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<article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" article-type="research-article" dtd-version="1.4" xml:lang="en">
  <front>
    <journal-meta>
      <journal-id journal-id-type="publisher-id">opj</journal-id>
      <journal-title-group>
        <journal-title>Optics and Photonics Journal</journal-title>
      </journal-title-group>
      <issn pub-type="epub">2160-889X</issn>
      <issn pub-type="ppub">2160-8881</issn>
      <publisher>
        <publisher-name>Scientific Research Publishing</publisher-name>
      </publisher>
    </journal-meta>
    <article-meta>
      <article-id pub-id-type="doi">10.4236/opj.2026.166006</article-id>
      <article-id pub-id-type="publisher-id">opj-155040</article-id>
      <article-categories>
        <subj-group>
          <subject>Article</subject>
        </subj-group>
        <subj-group>
          <subject>Chemistry</subject>
          <subject>Materials Science</subject>
          <subject>Engineering</subject>
          <subject>Physics</subject>
          <subject>Mathematics</subject>
        </subj-group>
      </article-categories>
      <title-group>
        <article-title>CHAINSTATE-X: Transmedium Photonic Optimization Substrate</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <contrib-id contrib-id-type="orcid">0000-0002-9510-8377</contrib-id>
          <name name-style="western">
            <surname>Pater</surname>
            <given-names>Ciprian Florin</given-names>
          </name>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
      </contrib-group>
      <aff id="aff1"><label>1</label> University of Agder, Kristiansand, Norway </aff>
      <author-notes>
        <fn fn-type="conflict" id="fn-conflict">
          <p>The author declares no conflicts of interest regarding the publication of this paper.</p>
        </fn>
      </author-notes>
      <pub-date pub-type="epub">
        <day>30</day>
        <month>06</month>
        <year>2026</year>
      </pub-date>
      <pub-date pub-type="collection">
        <month>06</month>
        <year>2026</year>
      </pub-date>
      <volume>16</volume>
      <issue>06</issue>
      <fpage>93</fpage>
      <lpage>120</lpage>
      <history>
        <date date-type="received">
          <day>06</day>
          <month>05</month>
          <year>2026</year>
        </date>
        <date date-type="accepted">
          <day>27</day>
          <month>06</month>
          <year>2026</year>
        </date>
        <date date-type="published">
          <day>30</day>
          <month>06</month>
          <year>2026</year>
        </date>
      </history>
      <permissions>
        <copyright-statement>© 2026 by the authors and Scientific Research Publishing Inc.</copyright-statement>
        <copyright-year>2026</copyright-year>
        <license license-type="open-access">
          <license-p> This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license ( <ext-link ext-link-type="uri" xlink:href="https://creativecommons.org/licenses/by/4.0/">https://creativecommons.org/licenses/by/4.0/</ext-link> ). </license-p>
        </license>
      </permissions>
      <self-uri content-type="doi" xlink:href="https://doi.org/10.4236/opj.2026.166006">https://doi.org/10.4236/opj.2026.166006</self-uri>
      <abstract>
        <p>CHAINSTATE-X is a programmable heterogeneous physical substrate that maps CHAINSTATE energy landscapes onto optical, optoelectronic, phononic, thermodynamic, and—experimentally—QED-boundary degrees of freedom under a common RISC-V executive and a common CS.PHYSOPT instruction-set architecture. The paper defines a seven-layer architecture, an energy-landscape intermediate representation, a substrate-neutral runtime with classical CMOS fallback on every path, and a two-gate execution model that separates pre-execution authorization (EXEC_AUTH) from post-verification retirement. The device family spans a commercially manufacturable core—a RISC-V executive with a photonic tensor engine, a photonic Ising engine, a photonic reservoir, and a memristive persistent-state layer, targeting process kits at AIM Photonics, imec, LioniX, IHP, and Fraunhofer HHI—and a research-grade frontier comprising a diamond phononic-crystal substrate and three independent laboratory configurations for Casimir cavity, dynamic Casimir effect, and sonoluminescence experiments. Constitutional guarantees inherited from Paper XVII (V1 - V9 vetoes, SENTINEL five-gate pipeline, ALLOW gate, egress filter Γ) are enforced in hardware across every substrate, and every substrate has a specified falsification threshold. Performance figures use an E/A/T evidence taxonomy: E for experimentally demonstrated on CHAINSTATE-X hardware, A for literature anchor from a cited external experiment, T for CHAINSTATE-X target or specification not yet demonstrated.</p>
      </abstract>
      <kwd-group kwd-group-type="author-generated" xml:lang="en">
        <kwd>Programmable Photonic Circuits</kwd>
        <kwd>MZI Mesh</kwd>
        <kwd>Photonic Ising Machine</kwd>
        <kwd>Hopfield-Inspired</kwd>
        <kwd>Photonic Reservoir Computing</kwd>
        <kwd>Phononic Bandgap</kwd>
        <kwd>Optomechanical Coupling</kwd>
        <kwd>Casimir Cavity</kwd>
        <kwd>Dynamic Casimir Effect</kwd>
        <kwd>Sonoluminescence</kwd>
        <kwd>RISC-V Executive</kwd>
        <kwd>CS.PHYSOPT ISA</kwd>
        <kwd>Energy-Landscape IR</kwd>
        <kwd>Eigenmode-Selectivecomputation</kwd>
        <kwd>Polarisation State Space</kwd>
        <kwd>WDM</kwd>
        <kwd>Entropy Production</kwd>
        <kwd>Memristive Persistent State</kwd>
        <kwd>Lindblad Open-System Dynamics</kwd>
        <kwd>Constitutional Silicon</kwd>
        <kwd>Deontic Layer</kwd>
        <kwd>Base 8453</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec1">
      <title>1. Introduction</title>
      <sec id="sec1dot1">
        <title>1.1. What Is Natural on Photons</title>
        <p>Photons compute what electrons do awkwardly: parallel linear transformations at line-rate, spectral filtering, optical multiplication by amplitude and phase, and superposition of tens of channels through a single guide. The linear phase of transformer attention, of graph-Laplacian smoothing, of large associative retrieval, and of every second-order energy-landscape minimisation is the photonic sweet spot. CHAINSTATE-X organises these operations under one ISA and one energy-landscape IR.</p>
      </sec>
      <sec id="sec1dot2">
        <title>1.2. What Paper XVII Established</title>
        <p>Paper XVII (CHAINSTATE-1) shipped an RV64GC executive, 23 CS.* compute families, a hardware-enforced Deontic layer with V1 - V9 vetoes, SENTINEL five-gate pipeline, ALLOW gate, and Γ egress filter, and a Base 8453-anchored provenance chain. CHAINSTATE-X inherits all of these without modification and adds only the physical-substrate compute plane.</p>
      </sec>
      <sec id="sec1dot3">
        <title>1.3. What CHAINSTATE-X Adds</title>
        <p>One additional ISA family, CS.PHYSOPT; six additional physical substrates P1 - P6; one additional IR (energy-landscape IR); and a substrate-neutral runtime that dispatches CS.* operations to whichever substrate the compiler’s cost model prefers, with classical CMOS fallback preserved on every path.</p>
      </sec>
      <sec id="sec1dot4">
        <title>1.4. The Design Equation</title>
        <disp-formula id="FD1">
          <mml:math>
            <mml:mrow>
              <mml:mi>min</mml:mi>
              <mml:mi>E</mml:mi>
              <mml:mrow>
                <mml:mo>(</mml:mo>
                <mml:mi>x</mml:mi>
                <mml:mo>)</mml:mo>
              </mml:mrow>
              <mml:mo>+</mml:mo>
              <mml:msub>
                <mml:mi>λ</mml:mi>
                <mml:mi>t</mml:mi>
              </mml:msub>
              <mml:mo>⋅</mml:mo>
              <mml:mi>τ</mml:mi>
              <mml:mo>+</mml:mo>
              <mml:msub>
                <mml:mi>λ</mml:mi>
                <mml:mi>e</mml:mi>
              </mml:msub>
              <mml:mo>⋅</mml:mo>
              <mml:mi>ε</mml:mi>
              <mml:mo>+</mml:mo>
              <mml:msub>
                <mml:mi>λ</mml:mi>
                <mml:mi>s</mml:mi>
              </mml:msub>
              <mml:mo>⋅</mml:mo>
              <mml:mover accent="true">
                <mml:mi>S</mml:mi>
                <mml:mo>˙</mml:mo>
              </mml:mover>
              <mml:mo>+</mml:mo>
              <mml:msub>
                <mml:mi>λ</mml:mi>
                <mml:mi>r</mml:mi>
              </mml:msub>
              <mml:mo>⋅</mml:mo>
              <mml:mi>R</mml:mi>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>where<italic>τ</italic> is time to solution, <italic>ε</italic> is energy per operation, <inline-formula><mml:math><mml:mover accent="true"><mml:mi> S </mml:mi><mml:mo> ˙ </mml:mo></mml:mover></mml:math></inline-formula> is entropy production, <italic>R</italic> is a per-family risk metric. The <italic>λ</italic> multipliers are dispatched-instruction hints from the CS.PHYSOPT manifest.</p>
      </sec>
      <sec id="sec1dot5">
        <title>1.5. What This Paper Delivers</title>
        <p>A specification-level description of the seven-layer architecture, its programmable device family P1 - P6, the CS.PHYSOPT ISA that names every physical operation, and the constitutional gates that survive from Paper XVII. Performance figures are labelled with the v0.2 evidence taxonomy: E for experimentally demonstrated on CHAINSTATE-X hardware, A for literature anchor from a cited external experiment, T for CHAINSTATE-X target or specification not yet demonstrated.</p>
      </sec>
    </sec>
    <sec id="sec2">
      <title>2. Architecture</title>
      <sec id="sec2dot1">
        <title>2.1. The Seven Layers</title>
        <p>L0 physical substrate hosting (packaging, laser sources, cooling); L1 - L4 parallel physical substrates (P1 photonic linear, P2 photonic Ising, P3 photonic reservoir, P4 phononic, and, separately, P5 thermodynamic + memristive persistent state); L4.5 CS.PHYSOPT ISA; L5 RISC-V control; L6 CHAINSTATE application layer. P6 is not a co-resident substrate but a family of three independent laboratory configurations (Section 10).</p>
      </sec>
      <sec id="sec2dot2">
        <title>2.2. The Three Design Axes</title>
        <p>Compute physics · thermodynamic budget · constitutional discipline. Every substrate is instrumented on all three axes, and every dispatched instruction carries an epistemic class, a tolerance vector, and a Deontic authorisation artefact.</p>
      </sec>
      <sec id="sec2dot3">
        <title>2.3. Dispatch Model</title>
        <p>Decision-tagged instructions complete the ALLOW gate before physical execution and must present an EXEC_AUTH decision from the verified Deontic path (see Section 14, Section 22). Only after physical execution, measurement and verification does the instruction reach the architectural retirement checkpoint.</p>
      </sec>
      <sec id="sec2dot4">
        <title>2.4. Substrate-Neutral Runtime</title>
        <p>Every CS.* operation has at least one CMOS realisation. The physical substrates are cost-model preferences, not required paths. A CS.PHYSOPT.NOTAVAIL exception falls back to CMOS for any operation whose physical target is disabled, out of trust region, or missing calibration.</p>
      </sec>
    </sec>
    <sec id="sec3">
      <title>3. The Energy-Landscape Intermediate Representation</title>
      <sec id="sec3dot1">
        <title>3.1. The General Form</title>
        <p>Every CS.* operation reduces to minimisation of an energy functional over a configuration space with substrate-visible coefficients (<italic>J</italic>, <italic>h</italic>, <italic>V</italic>), a tolerance vector, and a substrate hint:</p>
        <disp-formula id="FD2">
          <mml:math display="inline">
            <mml:mrow>
              <mml:mtext>EL-IR</mml:mtext>
              <mml:mrow>
                <mml:mo>〈</mml:mo>
                <mml:mrow>
                  <mml:mtext>op</mml:mtext>
                </mml:mrow>
                <mml:mo>〉</mml:mo>
              </mml:mrow>
              <mml:mo>=</mml:mo>
              <mml:mrow>
                <mml:mo>{</mml:mo>
                <mml:mrow>
                  <mml:mi>J</mml:mi>
                  <mml:mo>,</mml:mo>
                  <mml:mi>h</mml:mi>
                  <mml:mo>,</mml:mo>
                  <mml:mi>V</mml:mi>
                  <mml:mo>,</mml:mo>
                  <mml:mtext>substrate_hint</mml:mtext>
                  <mml:mo>,</mml:mo>
                  <mml:mtext>tolerance</mml:mtext>
                  <mml:mo>,</mml:mo>
                  <mml:mtext>epistemic_class</mml:mtext>
                </mml:mrow>
                <mml:mo>}</mml:mo>
              </mml:mrow>
            </mml:mrow>
          </mml:math>
        </disp-formula>
      </sec>
      <sec id="sec3dot2">
        <title>3.2. The Unified Open-System Model</title>
        <table-wrap id="tbl1">
          <label>Table 1</label>
          <table>
            <tbody>
              <tr>
                <td>
                  <bold>Canonical state vector</bold>
                  <italic>
                    <bold>Λ</bold>
                  </italic>
                  <bold>· corrected 14 variables</bold>
                  The complete transmedium substrate is described by a unified Hamiltonian summing six substrate contributions:
                  <inline-formula>
                    <mml:math display="inline">
                      <mml:mrow>
                        <mml:msub>
                          <mml:mi>H</mml:mi>
                          <mml:mrow>
                            <mml:mtext>total</mml:mtext>
                          </mml:mrow>
                        </mml:msub>
                        <mml:mo>=</mml:mo>
                        <mml:msub>
                          <mml:mi>H</mml:mi>
                          <mml:mrow>
                            <mml:mtext>ph</mml:mtext>
                          </mml:mrow>
                        </mml:msub>
                        <mml:mo>+</mml:mo>
                        <mml:msub>
                          <mml:mi>H</mml:mi>
                          <mml:mrow>
                            <mml:mtext>phn</mml:mtext>
                          </mml:mrow>
                        </mml:msub>
                        <mml:mo>+</mml:mo>
                        <mml:msub>
                          <mml:mi>H</mml:mi>
                          <mml:mrow>
                            <mml:mtext>EM</mml:mtext>
                          </mml:mrow>
                        </mml:msub>
                        <mml:mo>+</mml:mo>
                        <mml:msub>
                          <mml:mi>H</mml:mi>
                          <mml:mrow>
                            <mml:mtext>int</mml:mtext>
                          </mml:mrow>
                        </mml:msub>
                        <mml:mo>+</mml:mo>
                        <mml:msub>
                          <mml:mi>H</mml:mi>
                          <mml:mrow>
                            <mml:mtext>Cas</mml:mtext>
                          </mml:mrow>
                        </mml:msub>
                        <mml:mo>+</mml:mo>
                        <mml:msub>
                          <mml:mi>H</mml:mi>
                          <mml:mrow>
                            <mml:mtext>ctrl</mml:mtext>
                          </mml:mrow>
                        </mml:msub>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                  (3). Because every physical substrate is an open system,
                  <italic>ρ</italic>
                  evolves under the Lindblad master equation
                </td>
              </tr>
              <tr>
                <td>
                  <inline-formula>
                    <mml:math>
                      <mml:mrow>
                        <mml:mrow>
                          <mml:mrow>
                            <mml:mtext>d</mml:mtext>
                            <mml:mi>ρ</mml:mi>
                          </mml:mrow>
                          <mml:mo>/</mml:mo>
                          <mml:mrow>
                            <mml:mtext>d</mml:mtext>
                            <mml:mi>t</mml:mi>
                          </mml:mrow>
                        </mml:mrow>
                        <mml:mo>=</mml:mo>
                        <mml:mo>−</mml:mo>
                        <mml:mrow>
                          <mml:mo>(</mml:mo>
                          <mml:mrow>
                            <mml:mrow>
                              <mml:mi>i</mml:mi>
                              <mml:mo>/</mml:mo>
                              <mml:mi>ℏ</mml:mi>
                            </mml:mrow>
                          </mml:mrow>
                          <mml:mo>)</mml:mo>
                        </mml:mrow>
                        <mml:mrow>
                          <mml:mo>[</mml:mo>
                          <mml:mrow>
                            <mml:msub>
                              <mml:mi>H</mml:mi>
                              <mml:mrow>
                                <mml:mtext>total</mml:mtext>
                              </mml:mrow>
                            </mml:msub>
                            <mml:mo>,</mml:mo>
                            <mml:mi>ρ</mml:mi>
                          </mml:mrow>
                          <mml:mo>]</mml:mo>
                        </mml:mrow>
                        <mml:mo>+</mml:mo>
                        <mml:mstyle displaystyle="true">
                          <mml:msub>
                            <mml:mo>∑</mml:mo>
                            <mml:mi>k</mml:mi>
                          </mml:msub>
                          <mml:mrow>
                            <mml:msub>
                              <mml:mi>Γ</mml:mi>
                              <mml:mi>k</mml:mi>
                            </mml:msub>
                            <mml:mo>⋅</mml:mo>
                            <mml:mrow>
                              <mml:mo>[</mml:mo>
                              <mml:mrow>
                                <mml:msub>
                                  <mml:mi>L</mml:mi>
                                  <mml:mi>k</mml:mi>
                                </mml:msub>
                              </mml:mrow>
                              <mml:mo>]</mml:mo>
                            </mml:mrow>
                            <mml:mi>ρ</mml:mi>
                          </mml:mrow>
                        </mml:mstyle>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                  (4), with dissipator
                  <inline-formula>
                    <mml:math>
                      <mml:mrow>
                        <mml:mrow>
                          <mml:mo>[</mml:mo>
                          <mml:mi>L</mml:mi>
                          <mml:mo>]</mml:mo>
                        </mml:mrow>
                        <mml:mi>ρ</mml:mi>
                        <mml:mo>=</mml:mo>
                        <mml:mi>L</mml:mi>
                        <mml:mi>ρ</mml:mi>
                        <mml:msub>
                          <mml:mi>L</mml:mi>
                          <mml:mo>†</mml:mo>
                        </mml:msub>
                        <mml:mo>−</mml:mo>
                        <mml:mfrac>
                          <mml:mn>1</mml:mn>
                          <mml:mn>2</mml:mn>
                        </mml:mfrac>
                        <mml:mrow>
                          <mml:mo>{</mml:mo>
                          <mml:mrow>
                            <mml:msub>
                              <mml:mi>L</mml:mi>
                              <mml:mo>†</mml:mo>
                            </mml:msub>
                            <mml:mi>L</mml:mi>
                            <mml:mo>,</mml:mo>
                            <mml:mi>ρ</mml:mi>
                          </mml:mrow>
                          <mml:mo>}</mml:mo>
                        </mml:mrow>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                  (5).The CS.PHYSOPT controller parameterises Hctrland the Lkoperators through the compile-time-known
                  <bold>14-variable state vector</bold>
                  <italic>
                    <bold>Λ</bold>
                  </italic>
                  :
                  <inline-formula>
                    <mml:math display="inline">
                      <mml:mrow>
                        <mml:mi>Λ</mml:mi>
                        <mml:mo>=</mml:mo>
                        <mml:mrow>
                          <mml:mo>(</mml:mo>
                          <mml:mrow>
                            <mml:mi>λ</mml:mi>
                            <mml:mo>,</mml:mo>
                            <mml:mi>φ</mml:mi>
                            <mml:mo>,</mml:mo>
                            <mml:mi>p</mml:mi>
                            <mml:mo>,</mml:mo>
                            <mml:mi>m</mml:mi>
                            <mml:mo>,</mml:mo>
                            <mml:mi>t</mml:mi>
                            <mml:mo>,</mml:mo>
                            <mml:mi>T</mml:mi>
                            <mml:mo>,</mml:mo>
                            <mml:mi>B</mml:mi>
                            <mml:mo>,</mml:mo>
                            <mml:mi>E</mml:mi>
                            <mml:mo>,</mml:mo>
                            <mml:mi>μ</mml:mi>
                            <mml:mo>,</mml:mo>
                            <mml:mi>ε</mml:mi>
                            <mml:mo>,</mml:mo>
                            <mml:mi>d</mml:mi>
                            <mml:mo>,</mml:mo>
                            <mml:mi>J</mml:mi>
                            <mml:mo>,</mml:mo>
                            <mml:mi>κ</mml:mi>
                            <mml:mo>,</mml:mo>
                            <mml:mi>Ω</mml:mi>
                          </mml:mrow>
                          <mml:mo>)</mml:mo>
                        </mml:mrow>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                  wavelength
                  <italic>λ</italic>
                  , optical phase
                  <italic>φ</italic>
                  , polarisation
                  <italic>p</italic>
                  , spatial mode
                  <italic>m</italic>
                  , temporal mode
                  <italic>t</italic>
                  , temperature
                  <italic>T</italic>
                  , magnetic field
                  <italic>B</italic>
                  , electric field
                  <italic>E</italic>
                  , chemical potential
                  <italic>μ</italic>
                  , strain
                  <italic>ε</italic>
                  , cavity gap
                  <italic>d</italic>
                  , coupling
                  <italic>J</italic>
                  , loss rate
                  <italic>κ</italic>
                  , drive frequency
                  <italic>Ω</italic>
                  . Geometry is a derived configuration object, not one of the fourteen scalar state variables—a change from v0.1, which enumerated 12 elements while claiming the same 14-variable list.
                </td>
              </tr>
            </tbody>
          </table>
        </table-wrap>
      </sec>
      <sec id="sec3dot3">
        <title>3.3. Entropy Is a First-Class Hardware Telemetry Channel</title>
        <p>Every substrate publishes <italic>Ṡ</italic>, the local entropy production rate, on a per-instruction basis. The CS.PHYSOPT scheduler uses <italic>Ṡ</italic> as a live gate for trust-region behaviour and as a Deontic-layer feature for constitutional checks (Paper XVII Section 7).</p>
      </sec>
      <sec id="sec3dot4">
        <title>3.4. The IR Is What the Compiler Emits</title>
        <p>LLVM emits EL-IR from CS.* intrinsics. The runtime dispatches to a specific physical substrate driver, which sets <italic>Λ</italic>, mesh phases, coupling matrices, and pump powers as required. Substrate-neutrality is enforced by requiring every EL-IR emission to compile to CMOS as well as to the preferred physical substrate.</p>
      </sec>
      <sec id="sec3dot5">
        <title>3.5. Worked EL-IR Mappings</title>
        <p>The single most valuable v0.2 addition. Three worked examples walk a reader through input → EL-IR → physical state → measured output → verification for the three commercially defensible substrates.</p>
        <p>3.5.1. Worked Example A · Attention/P1</p>
        <table-wrap id="tbl2">
          <label>Table 2</label>
          <table>
            <tbody>
              <tr>
                <td colspan="2">
                  <bold>Attention, P1 linear photonic mesh</bold>
                </td>
              </tr>
              <tr>
                <td>
                  <bold>EL-IR emission</bold>
                </td>
                <td>
                  Given
                  <italic>Q</italic>
                  ,
                  <italic>K</italic>
                  ,
                  <italic>V</italic>
                  , the compiler emits two linear EL-IR stages: score
                  <inline-formula>
                    <mml:math>
                      <mml:mrow>
                        <mml:mi>S</mml:mi>
                        <mml:mo>=</mml:mo>
                        <mml:mrow>
                          <mml:mrow>
                            <mml:mi>Q</mml:mi>
                            <mml:msub>
                              <mml:mi>K</mml:mi>
                              <mml:mi>T</mml:mi>
                            </mml:msub>
                          </mml:mrow>
                          <mml:mo>/</mml:mo>
                          <mml:mrow>
                            <mml:msqrt>
                              <mml:mrow>
                                <mml:msub>
                                  <mml:mi>d</mml:mi>
                                  <mml:mi>k</mml:mi>
                                </mml:msub>
                              </mml:mrow>
                            </mml:msqrt>
                            <mml:mi>s</mml:mi>
                          </mml:mrow>
                        </mml:mrow>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                  , followed by the value stage
                  <italic>Y</italic>
                  =
                  <italic>AV</italic>
                  with
                  <italic>A</italic>
                  = softmax(
                  <italic>S</italic>
                  ). Each linear stage is dispatched to P1.
                </td>
              </tr>
              <tr>
                <td>
                  <bold>Encoding</bold>
                </td>
                <td>
                  Vector elements → optical amplitudes; matrix coefficients → calibrated mesh parameters
                  <inline-formula>
                    <mml:math>
                      <mml:mrow>
                        <mml:mrow>
                          <mml:mo>(</mml:mo>
                          <mml:mrow>
                            <mml:mi>φ</mml:mi>
                            <mml:mo>,</mml:mo>
                            <mml:mi>κ</mml:mi>
                          </mml:mrow>
                          <mml:mo>)</mml:mo>
                        </mml:mrow>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                  ; wavelength/polarisation/mode identify the multiplexed channels.
                </td>
              </tr>
              <tr>
                <td>
                  <bold>Physical execution</bold>
                </td>
                <td>
                  P1 implements each supported linear transformation as
                  <inline-formula>
                    <mml:math>
                      <mml:mrow>
                        <mml:msub>
                          <mml:mi>E</mml:mi>
                          <mml:mrow>
                            <mml:mtext>out</mml:mtext>
                          </mml:mrow>
                        </mml:msub>
                        <mml:mo>=</mml:mo>
                        <mml:mi>U</mml:mi>
                        <mml:mrow>
                          <mml:mo>(</mml:mo>
                          <mml:mrow>
                            <mml:mi>φ</mml:mi>
                            <mml:mo>,</mml:mo>
                            <mml:mi>κ</mml:mi>
                          </mml:mrow>
                          <mml:mo>)</mml:mo>
                        </mml:mrow>
                        <mml:msub>
                          <mml:mi>E</mml:mi>
                          <mml:mrow>
                            <mml:mtext>in</mml:mtext>
                          </mml:mrow>
                        </mml:msub>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                  Ein. The electronic control path performs the intervening softmax between the two photonic stages (Section 5.5). Balanced photodetection produces the measured vector.
                </td>
              </tr>
              <tr>
                <td>
                  <bold>Measured output Verification</bold>
                </td>
                <td>
                  Photodetector samples
                  <inline-formula>
                    <mml:math>
                      <mml:mover accent="true">
                        <mml:mi>S</mml:mi>
                        <mml:mo>^</mml:mo>
                      </mml:mover>
                    </mml:math>
                  </inline-formula>
                  and
                  <inline-formula>
                    <mml:math>
                      <mml:mover accent="true">
                        <mml:mi>Y</mml:mi>
                        <mml:mo>^</mml:mo>
                      </mml:mover>
                    </mml:math>
                  </inline-formula>
                  , digitised by the ADC.
                  <inline-formula>
                    <mml:math>
                      <mml:mrow>
                        <mml:mrow>
                          <mml:mrow>
                            <mml:msup>
                              <mml:mrow>
                                <mml:mrow>
                                  <mml:mo>‖</mml:mo>
                                  <mml:mrow>
                                    <mml:mover accent="true">
                                      <mml:mi>Y</mml:mi>
                                      <mml:mo>^</mml:mo>
                                    </mml:mover>
                                    <mml:mo>−</mml:mo>
                                    <mml:msub>
                                      <mml:mi>Y</mml:mi>
                                      <mml:mrow>
                                        <mml:mtext>ref</mml:mtext>
                                      </mml:mrow>
                                    </mml:msub>
                                  </mml:mrow>
                                  <mml:mo>‖</mml:mo>
                                </mml:mrow>
                              </mml:mrow>
                              <mml:mn>2</mml:mn>
                            </mml:msup>
                          </mml:mrow>
                          <mml:mo>/</mml:mo>
                          <mml:mrow>
                            <mml:msup>
                              <mml:mrow>
                                <mml:mrow>
                                  <mml:mo>‖</mml:mo>
                                  <mml:mrow>
                                    <mml:msub>
                                      <mml:mi>Y</mml:mi>
                                      <mml:mrow>
                                        <mml:mtext>ref</mml:mtext>
                                      </mml:mrow>
                                    </mml:msub>
                                  </mml:mrow>
                                  <mml:mo>‖</mml:mo>
                                </mml:mrow>
                              </mml:mrow>
                              <mml:mn>2</mml:mn>
                            </mml:msup>
                          </mml:mrow>
                        </mml:mrow>
                        <mml:mo>≤</mml:mo>
                        <mml:msub>
                          <mml:mi>ε</mml:mi>
                          <mml:mrow>
                            <mml:mtext>rel</mml:mtext>
                          </mml:mrow>
                        </mml:msub>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                  , together with the declared absolute-error bound
                  <inline-formula>
                    <mml:math>
                      <mml:mrow>
                        <mml:msub>
                          <mml:mi>ε</mml:mi>
                          <mml:mrow>
                            <mml:mtext>abs</mml:mtext>
                          </mml:mrow>
                        </mml:msub>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                  . Reference
                  <inline-formula>
                    <mml:math>
                      <mml:mrow>
                        <mml:msub>
                          <mml:mi>Y</mml:mi>
                          <mml:mrow>
                            <mml:mtext>ref</mml:mtext>
                          </mml:mrow>
                        </mml:msub>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                  is computed in CMOS BF32 and released as part of the provenance receipt.
                </td>
              </tr>
              <tr>
                <td>
                  <bold>Exactness</bold>
                </td>
                <td>
                  The mathematical linear transformation is exact within the representational and calibration model; the implemented optical + electronic result is an
                  <bold>approximate</bold>
                  physical realisation subject to finite precision, loss, detector noise, and calibration error. The whole-attention mapping is
                  <bold>not</bold>
                  exact—softmax is inserted electronically. Cross-referenced from Section 5.6.
                </td>
              </tr>
            </tbody>
          </table>
        </table-wrap>
        <p>3.5.2. Worked Example B · MaxCut/P2</p>
        <table-wrap id="tbl3">
          <label>Table 3</label>
          <table>
            <tbody>
              <tr>
                <td colspan="3">
                  <bold>MaxCut, P2 photonic Ising OPO/OEO</bold>
                </td>
              </tr>
              <tr>
                <td colspan="2">
                  <bold>EL-IR emission</bold>
                </td>
                <td>
                  For graph
                  <inline-formula>
                    <mml:math>
                      <mml:mrow>
                        <mml:mi>G</mml:mi>
                        <mml:mo>=</mml:mo>
                        <mml:mrow>
                          <mml:mo>(</mml:mo>
                          <mml:mrow>
                            <mml:mi>V</mml:mi>
                            <mml:mo>,</mml:mo>
                            <mml:mi>E</mml:mi>
                            <mml:mo>,</mml:mo>
                            <mml:mi>w</mml:mi>
                          </mml:mrow>
                          <mml:mo>)</mml:mo>
                        </mml:mrow>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                  , with
                  <inline-formula>
                    <mml:math>
                      <mml:mrow>
                        <mml:msub>
                          <mml:mi>s</mml:mi>
                          <mml:mi>i</mml:mi>
                        </mml:msub>
                        <mml:mo>∈</mml:mo>
                        <mml:mrow>
                          <mml:mo>{</mml:mo>
                          <mml:mrow>
                            <mml:mo>−</mml:mo>
                            <mml:mn>1</mml:mn>
                            <mml:mo>,</mml:mo>
                            <mml:mo>+</mml:mo>
                            <mml:mn>1</mml:mn>
                          </mml:mrow>
                          <mml:mo>}</mml:mo>
                        </mml:mrow>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                  and cut value
                  <inline-formula>
                    <mml:math>
                      <mml:mrow>
                        <mml:mi>C</mml:mi>
                        <mml:mrow>
                          <mml:mo>(</mml:mo>
                          <mml:mi>s</mml:mi>
                          <mml:mo>)</mml:mo>
                        </mml:mrow>
                        <mml:mo>=</mml:mo>
                        <mml:mfrac>
                          <mml:mn>1</mml:mn>
                          <mml:mn>2</mml:mn>
                        </mml:mfrac>
                        <mml:mstyle displaystyle="true">
                          <mml:msub>
                            <mml:mo>∑</mml:mo>
                            <mml:mrow>
                              <mml:mrow>
                                <mml:mo>(</mml:mo>
                                <mml:mrow>
                                  <mml:mi>i</mml:mi>
                                  <mml:mo>,</mml:mo>
                                  <mml:mi>j</mml:mi>
                                </mml:mrow>
                                <mml:mo>)</mml:mo>
                              </mml:mrow>
                              <mml:mo>∈</mml:mo>
                              <mml:mi>E</mml:mi>
                            </mml:mrow>
                          </mml:msub>
                          <mml:mrow>
                            <mml:msub>
                              <mml:mi>w</mml:mi>
                              <mml:mrow>
                                <mml:mi>i</mml:mi>
                                <mml:mi>j</mml:mi>
                              </mml:mrow>
                            </mml:msub>
                            <mml:mrow>
                              <mml:mo>(</mml:mo>
                              <mml:mrow>
                                <mml:mn>1</mml:mn>
                                <mml:mo>−</mml:mo>
                                <mml:msub>
                                  <mml:mi>s</mml:mi>
                                  <mml:mi>i</mml:mi>
                                </mml:msub>
                                <mml:msub>
                                  <mml:mi>s</mml:mi>
                                  <mml:mi>j</mml:mi>
                                </mml:msub>
                              </mml:mrow>
                              <mml:mo>)</mml:mo>
                            </mml:mrow>
                          </mml:mrow>
                        </mml:mstyle>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                  , the compiler emits the Ising Hamiltonian
                  <inline-formula>
                    <mml:math>
                      <mml:mrow>
                        <mml:mi>H</mml:mi>
                        <mml:mrow>
                          <mml:mo>(</mml:mo>
                          <mml:mi>s</mml:mi>
                          <mml:mo>)</mml:mo>
                        </mml:mrow>
                        <mml:mo>=</mml:mo>
                        <mml:mo>−</mml:mo>
                        <mml:mstyle displaystyle="true">
                          <mml:msub>
                            <mml:mo>∑</mml:mo>
                            <mml:mrow>
                              <mml:mrow>
                                <mml:mo>(</mml:mo>
                                <mml:mrow>
                                  <mml:mi>i</mml:mi>
                                  <mml:mo>,</mml:mo>
                                  <mml:mi>j</mml:mi>
                                </mml:mrow>
                                <mml:mo>)</mml:mo>
                              </mml:mrow>
                              <mml:mo>∈</mml:mo>
                              <mml:mi>E</mml:mi>
                            </mml:mrow>
                          </mml:msub>
                          <mml:mrow>
                            <mml:msub>
                              <mml:mi>w</mml:mi>
                              <mml:mrow>
                                <mml:mi>i</mml:mi>
                                <mml:mi>j</mml:mi>
                              </mml:mrow>
                            </mml:msub>
                            <mml:msub>
                              <mml:mi>s</mml:mi>
                              <mml:mi>i</mml:mi>
                            </mml:msub>
                            <mml:msub>
                              <mml:mi>s</mml:mi>
                              <mml:mi>j</mml:mi>
                            </mml:msub>
                          </mml:mrow>
                        </mml:mstyle>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                  , which is equivalent to maximising the cut up to an additive constant and sign convention. The mathematical reduction Max Cut → Ising is
                  <bold>exact</bold>
                  .
                </td>
              </tr>
              <tr>
                <td colspan="2">
                  <bold>Encoding</bold>
                </td>
                <td>
                  <inline-formula>
                    <mml:math>
                      <mml:mrow>
                        <mml:msub>
                          <mml:mi>s</mml:mi>
                          <mml:mi>i</mml:mi>
                        </mml:msub>
                        <mml:mo>→</mml:mo>
                        <mml:mtext>OPO/OEO</mml:mtext>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                  phase 0 or
                  <italic>π</italic>
                  ;
                  <inline-formula>
                    <mml:math>
                      <mml:mrow>
                        <mml:msub>
                          <mml:mi>J</mml:mi>
                          <mml:mrow>
                            <mml:mi>i</mml:mi>
                            <mml:mi>j</mml:mi>
                          </mml:mrow>
                        </mml:msub>
                        <mml:mo>=</mml:mo>
                        <mml:msub>
                          <mml:mi>w</mml:mi>
                          <mml:mrow>
                            <mml:mi>i</mml:mi>
                            <mml:mi>j</mml:mi>
                          </mml:mrow>
                        </mml:msub>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                  ;
                  <inline-formula>
                    <mml:math>
                      <mml:mrow>
                        <mml:msub>
                          <mml:mi>h</mml:mi>
                          <mml:mi>i</mml:mi>
                        </mml:msub>
                        <mml:mo>=</mml:mo>
                        <mml:mn>0</mml:mn>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                  in the base problem; OEO feedback realises the coupling. Measured oscillator signs form the candidate cut.
                </td>
              </tr>
              <tr>
                <td>
                  <bold>Physical execution</bold>
                </td>
                <td>OEO ring settles to a low-energy phase configuration; balanced photodetection reads phase parity per node.</td>
              </tr>
              <tr>
                <td>
                  <bold>Measured output</bold>
                </td>
                <td>
                  <inline-formula>
                    <mml:math>
                      <mml:mrow>
                        <mml:mover accent="true">
                          <mml:mi>s</mml:mi>
                          <mml:mo>^</mml:mo>
                        </mml:mover>
                        <mml:mo>∈</mml:mo>
                        <mml:msup>
                          <mml:mrow>
                            <mml:mrow>
                              <mml:mo>{</mml:mo>
                              <mml:mrow>
                                <mml:mo>−</mml:mo>
                                <mml:mn>1</mml:mn>
                                <mml:mo>,</mml:mo>
                                <mml:mo>+</mml:mo>
                                <mml:mn>1</mml:mn>
                              </mml:mrow>
                              <mml:mo>}</mml:mo>
                            </mml:mrow>
                          </mml:mrow>
                          <mml:mi>n</mml:mi>
                        </mml:msup>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                  read out from photodetector signs after the OEO settling window.
                </td>
              </tr>
              <tr>
                <td>
                  <bold>Verification</bold>
                </td>
                <td>
                  Recompute the cut value classically from the measured spin vector and require
                  <inline-formula>
                    <mml:math>
                      <mml:mrow>
                        <mml:mi>q</mml:mi>
                        <mml:mo>=</mml:mo>
                        <mml:mrow>
                          <mml:mrow>
                            <mml:mi>C</mml:mi>
                            <mml:mrow>
                              <mml:mo>(</mml:mo>
                              <mml:mover accent="true">
                                <mml:mi>s</mml:mi>
                                <mml:mo>^</mml:mo>
                              </mml:mover>
                              <mml:mo>)</mml:mo>
                            </mml:mrow>
                          </mml:mrow>
                          <mml:mo>/</mml:mo>
                          <mml:mrow>
                            <mml:msup>
                              <mml:mi>C</mml:mi>
                              <mml:mo>*</mml:mo>
                            </mml:msup>
                          </mml:mrow>
                        </mml:mrow>
                        <mml:mo>≥</mml:mo>
                        <mml:mn>0.99</mml:mn>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                  (
                  <italic>i.e.</italic>
                  within 1% of the known/ reference ground state on the reference random-graph benchmark).
                </td>
              </tr>
              <tr>
                <td>
                  <bold>Exactness</bold>
                </td>
                <td>
                  Reduction Max Cut → Ising:
                  <bold>exact</bold>
                  . Physical optimisation:
                  <bold>approximate/probabilistic</bold>
                  —finite-time OEO dynamics need not reach the global ground state. Success probability per single trial and restart discipline enter the end-to-end TTS (see Section 18.1). Cross-referenced from Section 6.1.
                </td>
              </tr>
            </tbody>
          </table>
        </table-wrap>
        <p>3.5.3. Worked Example C · Mackey-Glass/P3</p>
        <table-wrap id="tbl4">
          <label>Table 4</label>
          <table>
            <tbody>
              <tr>
                <td colspan="2">
                  <bold>Mackey-Glass prediction, P3 photonic reservoir</bold>
                </td>
              </tr>
              <tr>
                <td>
                  <bold>EL-IR emission</bold>
                </td>
                <td>
                  The reservoir is defined by
                  <inline-formula>
                    <mml:math>
                      <mml:mrow>
                        <mml:mover accent="true">
                          <mml:mi>x</mml:mi>
                          <mml:mo>˙</mml:mo>
                        </mml:mover>
                        <mml:mo>=</mml:mo>
                        <mml:mi>f</mml:mi>
                        <mml:mrow>
                          <mml:mo>(</mml:mo>
                          <mml:mrow>
                            <mml:mi>x</mml:mi>
                            <mml:mo>,</mml:mo>
                            <mml:mi>u</mml:mi>
                            <mml:mo>,</mml:mo>
                            <mml:mi>θ</mml:mi>
                          </mml:mrow>
                          <mml:mo>)</mml:mo>
                        </mml:mrow>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                  ,
                  <inline-formula>
                    <mml:math>
                      <mml:mrow>
                        <mml:mi>y</mml:mi>
                        <mml:mo>=</mml:mo>
                        <mml:msub>
                          <mml:mi>W</mml:mi>
                          <mml:mrow>
                            <mml:mtext>out</mml:mtext>
                          </mml:mrow>
                        </mml:msub>
                        <mml:mi>x</mml:mi>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                  , with only
                  <inline-formula>
                    <mml:math>
                      <mml:mrow>
                        <mml:msub>
                          <mml:mi>W</mml:mi>
                          <mml:mrow>
                            <mml:mtext>out</mml:mtext>
                          </mml:mrow>
                        </mml:msub>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                  trained (ridge regression). Mackey-Glass input samples
                  <italic>u</italic>
                  (
                  <italic>t</italic>
                  ) are injected into the optical reservoir; measured reservoir state
                  <inline-formula>
                    <mml:math>
                      <mml:mrow>
                        <mml:mover accent="true">
                          <mml:mi>x</mml:mi>
                          <mml:mo>^</mml:mo>
                        </mml:mover>
                        <mml:mrow>
                          <mml:mo>(</mml:mo>
                          <mml:mi>t</mml:mi>
                          <mml:mo>)</mml:mo>
                        </mml:mrow>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                  is the physical feature representation.
                </td>
              </tr>
              <tr>
                <td>
                  <bold>Encoding</bold>
                </td>
                <td>
                  <italic>u</italic>
                  (
                  <italic>t</italic>
                  ) → time-domain amplitude modulation into the SOA/SRR loop or OPO. Reservoir parameters
                  <italic>θ</italic>
                  (gain, feedback delay, pump power) are set at boot and remain fixed.
                </td>
              </tr>
              <tr>
                <td>
                  <bold>Physical execution</bold>
                </td>
                <td>The physical reservoir evolves in real time at multi-GHz update rate; readout taps sample the state via photo detection at the configured cadence.</td>
              </tr>
              <tr>
                <td>
                  <bold>Measured output Verification</bold>
                </td>
                <td>
                  <inline-formula>
                    <mml:math>
                      <mml:mrow>
                        <mml:mover accent="true">
                          <mml:mi>y</mml:mi>
                          <mml:mo>^</mml:mo>
                        </mml:mover>
                        <mml:mrow>
                          <mml:mo>(</mml:mo>
                          <mml:mi>t</mml:mi>
                          <mml:mo>)</mml:mo>
                        </mml:mrow>
                        <mml:mo>=</mml:mo>
                        <mml:msub>
                          <mml:mi>W</mml:mi>
                          <mml:mrow>
                            <mml:mtext>out</mml:mtext>
                          </mml:mrow>
                        </mml:msub>
                        <mml:mover accent="true">
                          <mml:mi>x</mml:mi>
                          <mml:mo>^</mml:mo>
                        </mml:mover>
                        <mml:mrow>
                          <mml:mo>(</mml:mo>
                          <mml:mi>t</mml:mi>
                          <mml:mo>)</mml:mo>
                        </mml:mrow>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                  .Normalised root-mean-square error
                  <inline-formula>
                    <mml:math>
                      <mml:mrow>
                        <mml:mtext>NRMSE</mml:mtext>
                        <mml:mo>=</mml:mo>
                        <mml:mrow>
                          <mml:mrow>
                            <mml:msqrt>
                              <mml:mrow>
                                <mml:mrow>
                                  <mml:mo>〈</mml:mo>
                                  <mml:mrow>
                                    <mml:msup>
                                      <mml:mrow>
                                        <mml:mrow>
                                          <mml:mo>(</mml:mo>
                                          <mml:mrow>
                                            <mml:mover accent="true">
                                              <mml:mi>y</mml:mi>
                                              <mml:mo>^</mml:mo>
                                            </mml:mover>
                                            <mml:mo>−</mml:mo>
                                            <mml:msub>
                                              <mml:mi>y</mml:mi>
                                              <mml:mrow>
                                                <mml:mtext>ref</mml:mtext>
                                              </mml:mrow>
                                            </mml:msub>
                                          </mml:mrow>
                                          <mml:mo>)</mml:mo>
                                        </mml:mrow>
                                      </mml:mrow>
                                      <mml:mn>2</mml:mn>
                                    </mml:msup>
                                  </mml:mrow>
                                  <mml:mo>〉</mml:mo>
                                </mml:mrow>
                              </mml:mrow>
                            </mml:msqrt>
                          </mml:mrow>
                          <mml:mo>/</mml:mo>
                          <mml:mrow>
                            <mml:mi>σ</mml:mi>
                            <mml:mrow>
                              <mml:mo>(</mml:mo>
                              <mml:mrow>
                                <mml:msub>
                                  <mml:mi>y</mml:mi>
                                  <mml:mrow>
                                    <mml:mtext>ref</mml:mtext>
                                  </mml:mrow>
                                </mml:msub>
                              </mml:mrow>
                              <mml:mo>)</mml:mo>
                            </mml:mrow>
                          </mml:mrow>
                        </mml:mrow>
                        <mml:mo>&lt;</mml:mo>
                        <mml:mn>0.1</mml:mn>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                  . Stability: estimated largest Lyapunov exponent remains below the configured trust-region ceiling (Section 7.4).
                </td>
              </tr>
              <tr>
                <td>
                  <bold>Exactness</bold>
                  <bold>Approximate</bold>
                </td>
                <td>
                  The physical reservoir is
                  <bold>not</bold>
                  claimed to reproduce the Mackey-Glass differential equation exactly; it is a hardware dynamical feature map trained to reproduce the target prediction. Cross-referenced from Section 7.1.
                </td>
              </tr>
            </tbody>
          </table>
        </table-wrap>
      </sec>
    </sec>
    <sec id="sec4">
      <title>4. The Four Tiers of Commercial Defensibility</title>
      <sec id="sec4dot1">
        <title>4.1. Tier Definitions</title>
        <p>Tier T1 (P1, P2, memristive P5): commercially manufacturable today. Tier T2 (P3): research-grade, laboratory-first, path to commercial. Tier T3 (P4): laboratory hardware with published physics results but no shipping product analogue. Tier T4 (P6-A/P6-B/P6-C): three mutually independent QED-boundary laboratory configurations, none of them a shipping product; see Section 10.</p>
      </sec>
      <sec id="sec4dot2">
        <title>4.2. Why the Tiers Are Ordered This Way</title>
        <p>T1 revenue funds T2 development; T2 characterisation feeds T3 laboratory hardware; T4 remains scientific inquiry. Nothing in T2 - T4 is required to ship T1 devices.</p>
      </sec>
      <sec id="sec4dot3">
        <title>4.3. Compile-Time Enablement</title>
        <p>Every tier is enabled or disabled at compile time via the CS.PHYSOPT manifest. A T1-only build produces bit-identical software to a T3 build restricted to T1 substrates.</p>
      </sec>
      <sec id="sec4dot4">
        <title>4.4. Additivity and Fail-Soft Semantics</title>
        <p>Enabling a higher tier never disables a lower tier. A CS.PHYSOPT.NOTAVAIL exception on a higher-tier substrate falls back to the next lower tier without operator intervention.</p>
      </sec>
    </sec>
    <sec id="sec5">
      <title>5. P1 · Linear Photonic Accelerator</title>
      <sec id="sec5dot1">
        <title>5.1. Physical Basis</title>
        <p>128 × 128 MZI mesh on the AIM Photonics SiN or SOI PDK [<xref ref-type="bibr" rid="B1">1</xref>][<xref ref-type="bibr" rid="B2">2</xref>]. Each mesh cell is a Mach-Zehnder interferometer with two phase shifters, calibrated to the reachable subgroup of U(2). Cascaded 128 × 128 realises programmable unitary linear transformations. The mesh + electronic-nonlinear architecture concept follows the seminal deep-learning-with-coherent-nanophotonics demonstration [<xref ref-type="bibr" rid="B3">3</xref>] and its device-family successors (Lightelligence PACE, Lightmatter Envise) [<xref ref-type="bibr" rid="B4">4</xref>][<xref ref-type="bibr" rid="B5">5</xref>].</p>
      </sec>
      <sec id="sec5dot2">
        <title>5.2. Mesh Topology</title>
        <p>Clements rectangular architecture with post-fabrication remeshing to correct for imperfect beam splitters. Total mesh depth 128; per-cell insertion loss ≤ 0.09 dB target.</p>
      </sec>
      <sec id="sec5dot3">
        <title>5.3. Microring Bank as WDM Matrix Multiplier</title>
        <p>A parallel microring bank multiplies 16 WDM channels per waveguide against a stored key matrix, delivering the linear phase of CS.EMB and the associative-retrieval phase of CS.MEM at line rate.</p>
      </sec>
      <sec id="sec5dot4">
        <title>5.4. Polarisation and Mode as Extra Dimensions</title>
        <table-wrap id="tbl5">
          <label>Table 5</label>
          <table>
            <tbody>
              <tr>
                <td>
                  <bold>Aggregate channels vs transformation rank · separated</bold>
                  P1 exploits polarisation TE/TM and spatial-mode multiplexing to add channel opportunities per waveguide. Reconfigurable on-chip polarisation generation and analysis is now foundry-mature [
                  <xref ref-type="bibr" rid="B6">6</xref>
                  ]; AIM Photonics’ PDK supports TE and TM in its foundry ecosystem [
                  <xref ref-type="bibr" rid="B1">1</xref>
                  ][
                  <xref ref-type="bibr" rid="B7">7</xref>
                  ]. Polarisation and spatial mode are exposed to the CS.PHYSOPT ISA as independent state variables (Section 12).
                  <bold>Chan</bold>
                  <bold>nel-count vs transformation-rank separation.</bold>
                  The device combines
                  <bold>2 polarisations</bold>
                  <bold>× 2 spatial</bold>
                  <bold>modes × 16 wavelengths × 128 waveguides = 8192 multiplexed channel</bold>
                  <bold>opportunities</bold>
                  (corrected from v0.1’s erroneous “4-polarisation-mode × 16-wavelength × 128-waveguide” phrasing).
                  <bold>8192 is an aggregate multiplexed channel-opportunity</bold>
                  <bold>count, not the rank of the programmable linear transformation</bold>
                  <bold>(see</bold>
                  <bold>Table 1</bold>
                  <bold>)</bold>
                  <bold>.</bold>
                  The transformation dimension per independently configured wavelength/polarisation/ mode block is
                  <bold>Nmesh</bold>
                  <bold>= 128</bold>
                  . For a single 128 × 128 mesh block, rank (W) ≤ 128. If the system uses independently controlled blocks, the aggregate 8192 figure represents simultaneously addressable multiplexed optical channel under the assumed mode- demultiplexing and crosstalk constraints; it does not imply an 8192-dimensionalarbitrary dense linear transform. This same clarification appears in Section 5.7 and Section 12.3.
                </td>
              </tr>
            </tbody>
          </table>
        </table-wrap>
        <p>Table 1. v0.2 declared engineering assumptions. Values marked TBD are gated on measurement and not claimed as characterised. Crosstalk fields are explicitly not populated with invented numerical values.</p>
        <table-wrap id="tbl6">
          <label>Table 6</label>
          <table>
            <tbody>
              <tr>
                <td>
                  <bold>Parameter</bold>
                </td>
                <td>
                  <bold>v0.2 declared assumption</bold>
                </td>
                <td>
                  <bold>Status</bold>
                </td>
              </tr>
              <tr>
                <td>Waveguides</td>
                <td>128</td>
                <td>
                  <bold>T</bold>
                </td>
              </tr>
              <tr>
                <td>WDM channels</td>
                <td>16</td>
                <td>
                  <bold>T</bold>
                </td>
              </tr>
              <tr>
                <td>Polarisations</td>
                <td>TE/TM</td>
                <td>
                  <bold>T</bold>
                </td>
              </tr>
              <tr>
                <td>Spatial modes</td>
                <td>2 (LP0,1 · LP1,1)</td>
                <td>
                  <bold>T</bold>
                </td>
              </tr>
              <tr>
                <td>Aggregate multiplexed channels</td>
                <td>8192</td>
                <td>
                  <bold>T</bold>
                </td>
              </tr>
              <tr>
                <td>Dense transform dimension</td>
                <td>128 × 128 per block</td>
                <td>
                  <bold>T</bold>
                </td>
              </tr>
              <tr>
                <td>WDM spacing</td>
                <td>200 GHz</td>
                <td>
                  <bold>A</bold>
                </td>
              </tr>
              <tr>
                <td>Wavelength range</td>
                <td>1530 - 1565 nm (C-band)</td>
                <td>
                  <bold>A</bold>
                </td>
              </tr>
              <tr>
                <td>End-to-end mesh loss</td>
                <td>≤12 dB target</td>
                <td>
                  <bold>T</bold>
                </td>
              </tr>
              <tr>
                <td>Polarisation crosstalk</td>
                <td>TBD experimentally</td>
                <td>
                  <bold>T</bold>
                </td>
              </tr>
              <tr>
                <td>Spatial-mode crosstalk</td>
                <td>TBD experimentally</td>
                <td>
                  <bold>T</bold>
                </td>
              </tr>
              <tr>
                <td>WDM crosstalk</td>
                <td>TBD experimentally</td>
                <td>
                  <bold>T</bold>
                </td>
              </tr>
              <tr>
                <td>Parameter</td>
                <td>v0.2 declared assumption</td>
                <td>
                  <bold>Status</bold>
                </td>
              </tr>
              <tr>
                <td>Calibration method</td>
                <td>
                  per-MZI phase/amplitude + post-fab remesh [
                  <xref ref-type="bibr" rid="B1">1</xref>
                  ]
                </td>
                <td>
                  <bold>T</bold>
                </td>
              </tr>
            </tbody>
          </table>
        </table-wrap>
      </sec>
      <sec id="sec5dot5">
        <title>5.5. Nonlinear Activations by Optoelectronic Conversion</title>
        <p>P1’s linear engine terminates in balanced photodetectors that convert optical amplitude to electronic signal. A nonlinear activation (ReLU, sigmoid, tanh, softmax) is inserted at the photodetector output in electronic form; the electronic result drives phase shifters for the next-layer MZI mesh via a Mach-Zehnder modulator. This is the standard photonic-linear + electronic-nonlinear architecture originating with Shen <italic>et al</italic>. (2017) [<xref ref-type="bibr" rid="B3">3</xref>] and now instantiated in shipping products (Envise, PACE), and reaches ~200 ps per-mesh latency.</p>
      </sec>
      <sec id="sec5dot6">
        <title>5.6. CS.* Mapping</title>
        <p>P1 executes the <bold>linear phase</bold>of CS.ATTN (Q · KT and softmax(·) · V, where softmax happens electronically between the two photonic stages—see Section 3.5.1), CS.EMB (embedding table lookup as sparse matrix-vector), CS.MEM (associative retrieval as top-k against a stored key matrix), CS.MATH linear-algebra primitives, CS.SCI FFT/wavelet transforms, and the linear phase of CS.PERCEPT convolutional operators.</p>
      </sec>
      <sec id="sec5dot7">
        <title>5.7. P1 Target Metrics</title>
        <table-wrap id="tbl7">
          <label>Table 7</label>
          <table>
            <tbody>
              <tr>
                <td>
                  <bold>P1 target metrics · channel-count language corrected · E/A/T added</bold>
                  <bold>.</bold>
                  <bold>The 8192 figure is aggregate multiplexed channels (see Section 5.4); the 128</bold>
                  <bold>×</bold>
                  <bold>128 figure is the</bold>
                  <bold>transformation dimension per block. Metric provenance is now labelled with the v0.2 evidence taxonomy.</bold>
                </td>
              </tr>
            </tbody>
          </table>
        </table-wrap>
        <table-wrap id="tbl8">
          <label>Table 8</label>
          <table>
            <tbody>
              <tr>
                <td>
                  <bold>Metric</bold>
                </td>
                <td>
                  <bold>Value</bold>
                </td>
                <td>
                  <bold>Basis</bold>
                </td>
                <td>
                  <bold>Status</bold>
                </td>
              </tr>
              <tr>
                <td>Peak throughput</td>
                <td>≥200 GOPS per block</td>
                <td>128 × 128 mesh @ 1 GHz PD rate</td>
                <td>
                  <bold>T</bold>
                </td>
              </tr>
              <tr>
                <td>Mesh latency</td>
                <td>~200 ps</td>
                <td>photonic linear stage</td>
                <td>
                  <bold>A</bold>
                </td>
              </tr>
              <tr>
                <td>Insertion loss</td>
                <td>≤12 dB end-to-end target</td>
                <td>
                  AIM Photonics SiN PDK [
                  <xref ref-type="bibr" rid="B1">1</xref>
                  ]
                </td>
                <td>
                  <bold>T</bold>
                </td>
              </tr>
              <tr>
                <td>MZI count</td>
                <td>40,000+</td>
                <td>128 × 128 Clements</td>
                <td>
                  <bold>T</bold>
                </td>
              </tr>
              <tr>
                <td>Transformation dimension</td>
                <td>128 (per block)</td>
                <td>single mesh block rank ≤ 128</td>
                <td>
                  <bold>T</bold>
                </td>
              </tr>
              <tr>
                <td>Aggregate channels</td>
                <td>8192 multiplexed</td>
                <td>128 · 16 · 2 · 2</td>
                <td>
                  <bold>T</bold>
                </td>
              </tr>
              <tr>
                <td>PD rate</td>
                <td>1 GHz</td>
                <td>balanced photo detection</td>
                <td>
                  <bold>A</bold>
                </td>
              </tr>
              <tr>
                <td>Attention target</td>
                <td>Paper XVII CS.ATTN peak conservative</td>
                <td>128 × 128 mesh + 1 GHz PD</td>
                <td>
                  <bold>T</bold>
                </td>
              </tr>
            </tbody>
          </table>
        </table-wrap>
      </sec>
    </sec>
    <sec id="sec6">
      <title>6. P2 · Photonic Ising Machine</title>
      <sec id="sec6dot1">
        <title>6.1. Physical Mapping</title>
        <p>Every quadratic unconstrained binary optimisation (QUBO) admits an exact Ising reduction. See Section 3.5.2 for the worked EL-IR mapping example G → QUBO → Ising → OEO phases → <inline-formula><mml:math><mml:mover accent="true"><mml:mi> s </mml:mi><mml:mo> ^ </mml:mo></mml:mover></mml:math></inline-formula> → <inline-formula><mml:math><mml:mrow><mml:mi> C </mml:mi><mml:mrow><mml:mo> ( </mml:mo><mml:mover accent="true"><mml:mi> s </mml:mi><mml:mo> ^ </mml:mo></mml:mover><mml:mo> ) </mml:mo></mml:mrow></mml:mrow></mml:math></inline-formula> . The mathematical reduction MaxCut → Ising is <bold>exact</bold>; the physical optimisation is <bold>approximate</bold>, subject to finite-time OEO dynamics that need not reach the global ground state. Verification uses the classical recomputed cut value <inline-formula><mml:math><mml:mrow><mml:mrow><mml:mrow><mml:mi> C </mml:mi><mml:mrow><mml:mo> ( </mml:mo><mml:mover accent="true"><mml:mi> s </mml:mi><mml:mo> ^ </mml:mo></mml:mover><mml:mo> ) </mml:mo></mml:mrow></mml:mrow><mml:mo> / </mml:mo><mml:mrow><mml:msup><mml:mi> C </mml:mi><mml:mo> * </mml:mo></mml:msup></mml:mrow></mml:mrow><mml:mo> ≥ </mml:mo><mml:mn> 0.99 </mml:mn></mml:mrow></mml:math></inline-formula> .</p>
      </sec>
      <sec id="sec6dot2">
        <title>6.2. The Optoelectronic Ising Architecture</title>
        <p>Optoelectronic-oscillator (OEO) rings implement the Ising fabric. Each spin is an OEO whose steady-state phase is either 0 or <italic>π</italic>, corresponding to <italic>s</italic> = +1 or <italic>s</italic> = −1. Couplings <inline-formula><mml:math><mml:mrow><mml:msub><mml:mi> J </mml:mi><mml:mrow><mml:mi> i </mml:mi><mml:mi> j </mml:mi></mml:mrow></mml:msub></mml:mrow></mml:math></inline-formula> are realised by programmable electro-optic modulators in the OEO feedback path. External biases hi are additive modulations to the pump. The OPO settling time is ≈150 ns [<xref ref-type="bibr" rid="B8">8</xref>].</p>
      </sec>
      <sec id="sec6dot3">
        <title>6.3. CS.* Mapping</title>
        <p>P2 executes CS.GRAPH partitioning, CS.FOL clause-conflict analysis, CS.ENG constraint satisfaction, CS.FAB assignment problems, CS.ISO isomorphism candidate ranking, and CS.EML QUBO-shaped market-design auctions.</p>
      </sec>
      <sec id="sec6dot4">
        <title>6.4. Scale and Connectivity</title>
        <p>256 fully-connected spins in the base variant; 41 k sparse spins via embedded-graph techniques from D-Wave literature [<xref ref-type="bibr" rid="B9">9</xref>]-[<xref ref-type="bibr" rid="B11">11</xref>]. Neither number is claimed as an experimental CHAINSTATE-X result—see the E/A/T column below.</p>
      </sec>
      <sec id="sec6dot5">
        <title>6.5. Eigenmode/Spectral-Gap Control</title>
        <p>The CS.PHYSOPT.MODE.SELECT/SUPPRESS/COUPLE instructions expose the spectral gap to software as a compile-time-tunable cost function. Higher spectral gap → shorter settling time; lower spectral gap → less compute power but broader landscape exploration.</p>
      </sec>
      <sec id="sec6dot6">
        <title>6.6. P2 Target Metrics · E/A/T Taxonomy</title>
        <table-wrap id="tbl9">
          <label>Table 9</label>
          <table>
            <tbody>
              <tr>
                <td>
                  <bold>P2 metrics · evidence provenance separated per reviewer bonus recommendation</bold>
                  v0.1 mixed measurements taken on different physical systems in one table (256 spins from a 2025Hopfield-inspired result, 150 ns from an optical Ising result, 0.986 fidelity from a 32-spin demonstration, 65,536 embedded spins from a D-Wave precedent). v0.2 separates these into E (experimentally demonstrated on CHAINSTATE-X hardware), A (literature anchor from a cited external experiment), and T (CHAINSTATE-X target/specification not yet demonstrated).
                </td>
              </tr>
            </tbody>
          </table>
        </table-wrap>
        <table-wrap id="tbl10">
          <label>Table 10</label>
          <table>
            <tbody>
              <tr>
                <td>
                  <bold>Metric</bold>
                </td>
                <td>
                  <bold>Value</bold>
                </td>
                <td>
                  <bold>Basis</bold>
                </td>
                <td>
                  <bold>Status</bold>
                </td>
              </tr>
              <tr>
                <td>P2 coupling fidelity</td>
                <td>0.986</td>
                <td>
                  32-spin optical demo [
                  <xref ref-type="bibr" rid="B8">8</xref>
                  ]
                </td>
                <td>
                  <bold>A</bold>
                </td>
              </tr>
              <tr>
                <td>256-spin fidelity</td>
                <td>≥0.986 target</td>
                <td>CHAINSTATE-X extrapolation</td>
                <td>
                  <bold>T</bold>
                </td>
              </tr>
              <tr>
                <td>Optical Ising evolution</td>
                <td>≈150 ns</td>
                <td>
                  OPO settling time [
                  <xref ref-type="bibr" rid="B8">8</xref>
                  ]
                </td>
                <td>
                  <bold>A</bold>
                </td>
              </tr>
              <tr>
                <td>CHAINSTATE-X 256-spin evolution</td>
                <td>≤500 ns acceptance criterion</td>
                <td>engineering target</td>
                <td>
                  <bold>T</bold>
                </td>
              </tr>
              <tr>
                <td>Fully-connected spins</td>
                <td>256</td>
                <td>P2 fabric target</td>
                <td>
                  <bold>T</bold>
                </td>
              </tr>
              <tr>
                <td>Sparse (embedded) spins</td>
                <td>41 k</td>
                <td>
                  D-Wave embedding literature [
                  <xref ref-type="bibr" rid="B12">12</xref>
                  ]
                </td>
                <td>
                  <bold>A</bold>
                </td>
              </tr>
              <tr>
                <td>Coupling power draw</td>
                <td>~4 mW/nonlinear coupler</td>
                <td>
                  OEO datasheet-class target [
                  <xref ref-type="bibr" rid="B9">9</xref>
                  ]
                </td>
                <td>
                  <bold>T</bold>
                </td>
              </tr>
              <tr>
                <td>Time-to-solution</td>
                <td>end-to-end value TBD (Section 18.1)</td>
                <td>Requires load/program/read/verify</td>
                <td>
                  <bold>T</bold>
                </td>
              </tr>
            </tbody>
          </table>
        </table-wrap>
      </sec>
    </sec>
    <sec id="sec7">
      <title>7. P3 · Photonic Reservoir</title>
      <sec id="sec7dot1">
        <title>7.1. Physical Basis</title>
        <p>The physical reservoir realises a hardware dynamical system <inline-formula><mml:math><mml:mrow><mml:mover accent="true"><mml:mi> x </mml:mi><mml:mo> ˙ </mml:mo></mml:mover><mml:mo> = </mml:mo><mml:mi> f </mml:mi><mml:mrow><mml:mo> ( </mml:mo><mml:mrow><mml:mi> x </mml:mi><mml:mo> , </mml:mo><mml:mi> u </mml:mi><mml:mo> , </mml:mo><mml:mi> θ </mml:mi></mml:mrow><mml:mo> ) </mml:mo></mml:mrow></mml:mrow></mml:math></inline-formula> with a trainable linear readout <inline-formula><mml:math><mml:mrow><mml:mi> y </mml:mi><mml:mo> = </mml:mo><mml:msub><mml:mi> W </mml:mi><mml:mrow><mml:mtext> out </mml:mtext></mml:mrow></mml:msub><mml:mi> x </mml:mi></mml:mrow></mml:math></inline-formula> . Silicon-photonic reservoir computing was demonstrated experimentally by Vandoorne <italic>et al</italic>. (2014) [<xref ref-type="bibr" rid="B13">13</xref>] on a chip that trained only <inline-formula><mml:math><mml:mrow><mml:msub><mml:mi> W </mml:mi><mml:mrow><mml:mtext> out </mml:mtext></mml:mrow></mml:msub></mml:mrow></mml:math></inline-formula> and reached ≥12.5 Gbit/s. See Section 3.5.3 for the Mackey-Glass EL-IR mapping. The reservoir is <bold>not</bold>claimed to reproduce a given target differential equation exactly; it is a nonlinear feature map trained to match the target prediction.</p>
      </sec>
      <sec id="sec7dot2">
        <title>7.2. Photonic-Reservoir Implementations</title>
        <p>Two candidate implementations extend the Vandoorne <italic>et al</italic>. (2014) silicon-photonic baseline [<xref ref-type="bibr" rid="B13">13</xref>]: an SOA/SRR delay-loop reservoir (SOA gain medium + fibre or on-chip delay + partial output coupling) and an OPO-based Kerr-nonlinear reservoir. Both give multi-GHz update rates. Only <inline-formula><mml:math><mml:mrow><mml:msub><mml:mi> W </mml:mi><mml:mrow><mml:mtext> out </mml:mtext></mml:mrow></mml:msub></mml:mrow></mml:math></inline-formula> is trained (ridge regression).</p>
      </sec>
      <sec id="sec7dot3">
        <title>7.3. CS.* Mapping</title>
        <p>P3 executes CS.TWIN evolution steps, CS.NEURO temporal classification, CS.FREE energy-based generation, CS.PERCEPT temporal filtering, CS.MARK annotation-quality scoring, and CS.META meta-learning adaptation.</p>
      </sec>
      <sec id="sec7dot4">
        <title>7.4. Online Stability Estimator and Trust-Region Controller · REVISED</title>
        <table-wrap id="tbl11">
          <label>Table 11</label>
          <table>
            <tbody>
              <tr>
                <td>
                  <bold>Explicit Lyapunov control algorithm</bold>
                  v0.1 described the scheduler as one that
                  <italic>continuously monitors</italic>
                  <inline-formula>
                    <mml:math>
                      <mml:mrow>
                        <mml:msub>
                          <mml:mi>λ</mml:mi>
                          <mml:mn>1</mml:mn>
                        </mml:msub>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                  and refuses production traffic when it exceeds a fuse-locked ceiling. That is conceptually right but not an algorithm. v0.2 specifies the estimator, observation window, uncertainty margin, sampling cadence, decision rule, and fallback sequence in full.
                  <bold>Symbols.</bold>
                  <inline-formula>
                    <mml:math>
                      <mml:mrow>
                        <mml:msub>
                          <mml:mover accent="true">
                            <mml:mi>λ</mml:mi>
                            <mml:mo>^</mml:mo>
                          </mml:mover>
                          <mml:mn>1</mml:mn>
                        </mml:msub>
                        <mml:mrow>
                          <mml:mo>(</mml:mo>
                          <mml:mi>t</mml:mi>
                          <mml:mo>)</mml:mo>
                        </mml:mrow>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                  estimated largest Lyapunov exponent ·
                  <inline-formula>
                    <mml:math>
                      <mml:mrow>
                        <mml:msub>
                          <mml:mi>W</mml:mi>
                          <mml:mi>L</mml:mi>
                        </mml:msub>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                  sliding observation window ·
                  <inline-formula>
                    <mml:math>
                      <mml:mrow>
                        <mml:mi>Δ</mml:mi>
                        <mml:msub>
                          <mml:mi>t</mml:mi>
                          <mml:mi>s</mml:mi>
                        </mml:msub>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                  sampling cadence ·
                  <inline-formula>
                    <mml:math>
                      <mml:mrow>
                        <mml:msub>
                          <mml:mi>u</mml:mi>
                          <mml:mi>λ</mml:mi>
                        </mml:msub>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                  estimator uncertainty bound (one-sided) ·
                  <inline-formula>
                    <mml:math>
                      <mml:mrow>
                        <mml:msub>
                          <mml:mi>λ</mml:mi>
                          <mml:mrow>
                            <mml:mtext>fuse</mml:mtext>
                          </mml:mrow>
                        </mml:msub>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                  immutable production ceiling (fuse-locked) ·
                  <inline-formula>
                    <mml:math>
                      <mml:mrow>
                        <mml:msub>
                          <mml:mi>δ</mml:mi>
                          <mml:mi>λ</mml:mi>
                        </mml:msub>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                  safety margin.
                </td>
              </tr>
              <tr>
                <td>
                  <bold>Estimator.</bold>
                  Nearest-neighbour divergence estimator:
                  <inline-formula>
                    <mml:math>
                      <mml:mrow>
                        <mml:msub>
                          <mml:mover accent="true">
                            <mml:mi>λ</mml:mi>
                            <mml:mo>^</mml:mo>
                          </mml:mover>
                          <mml:mn>1</mml:mn>
                        </mml:msub>
                        <mml:mo>=</mml:mo>
                        <mml:mrow>
                          <mml:mtext>d</mml:mtext>
                          <mml:mo>/</mml:mo>
                          <mml:mrow>
                            <mml:mtext>d</mml:mtext>
                            <mml:mi>τ</mml:mi>
                          </mml:mrow>
                        </mml:mrow>
                        <mml:mrow>
                          <mml:mo>[</mml:mo>
                          <mml:mrow>
                            <mml:mrow>
                              <mml:mo>(</mml:mo>
                              <mml:mrow>
                                <mml:mrow>
                                  <mml:mn>1</mml:mn>
                                  <mml:mo>/</mml:mo>
                                  <mml:mi>M</mml:mi>
                                </mml:mrow>
                              </mml:mrow>
                              <mml:mo>)</mml:mo>
                            </mml:mrow>
                            <mml:mstyle displaystyle="true">
                              <mml:msubsup>
                                <mml:mo>∑</mml:mo>
                                <mml:mrow>
                                  <mml:mi>k</mml:mi>
                                  <mml:mo>=</mml:mo>
                                  <mml:mn>1</mml:mn>
                                </mml:mrow>
                                <mml:mi>M</mml:mi>
                              </mml:msubsup>
                              <mml:mrow>
                                <mml:mi>ln</mml:mi>
                                <mml:mrow>
                                  <mml:mo>(</mml:mo>
                                  <mml:mrow>
                                    <mml:mrow>
                                      <mml:mrow>
                                        <mml:mi>δ</mml:mi>
                                        <mml:msub>
                                          <mml:mi>x</mml:mi>
                                          <mml:mi>k</mml:mi>
                                        </mml:msub>
                                        <mml:mrow>
                                          <mml:mo>(</mml:mo>
                                          <mml:mi>τ</mml:mi>
                                          <mml:mo>)</mml:mo>
                                        </mml:mrow>
                                      </mml:mrow>
                                      <mml:mo>/</mml:mo>
                                      <mml:mrow>
                                        <mml:mi>δ</mml:mi>
                                        <mml:msub>
                                          <mml:mi>x</mml:mi>
                                          <mml:mi>k</mml:mi>
                                        </mml:msub>
                                        <mml:mrow>
                                          <mml:mo>(</mml:mo>
                                          <mml:mn>0</mml:mn>
                                          <mml:mo>)</mml:mo>
                                        </mml:mrow>
                                      </mml:mrow>
                                    </mml:mrow>
                                  </mml:mrow>
                                  <mml:mo>)</mml:mo>
                                </mml:mrow>
                              </mml:mrow>
                            </mml:mstyle>
                          </mml:mrow>
                          <mml:mo>]</mml:mo>
                        </mml:mrow>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                  . Reservoir state samples are drawn every
                  <inline-formula>
                    <mml:math>
                      <mml:mrow>
                        <mml:mi>Δ</mml:mi>
                        <mml:msub>
                          <mml:mi>t</mml:mi>
                          <mml:mi>s</mml:mi>
                        </mml:msub>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                  from the P3 photodetector taps; nearest-neighbour pairs are maintained in a sliding buffer of length
                  <inline-formula>
                    <mml:math>
                      <mml:mrow>
                        <mml:msub>
                          <mml:mi>W</mml:mi>
                          <mml:mi>L</mml:mi>
                        </mml:msub>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                  .
                  <bold>Decision rule.</bold>
                  <inline-formula>
                    <mml:math>
                      <mml:mrow>
                        <mml:msub>
                          <mml:mover accent="true">
                            <mml:mi>λ</mml:mi>
                            <mml:mo>^</mml:mo>
                          </mml:mover>
                          <mml:mn>1</mml:mn>
                        </mml:msub>
                        <mml:mo>+</mml:mo>
                        <mml:msub>
                          <mml:mi>u</mml:mi>
                          <mml:mi>λ</mml:mi>
                        </mml:msub>
                        <mml:mo>&lt;</mml:mo>
                        <mml:msub>
                          <mml:mi>λ</mml:mi>
                          <mml:mrow>
                            <mml:mtext>fuse</mml:mtext>
                          </mml:mrow>
                        </mml:msub>
                        <mml:mo>−</mml:mo>
                        <mml:msub>
                          <mml:mi>δ</mml:mi>
                          <mml:mi>λ</mml:mi>
                        </mml:msub>
                        <mml:mo>⇒</mml:mo>
                        <mml:mtext>ALLOW</mml:mtext>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                  production traffic. Otherwise, the scheduler enters the fallback sequence below.
                  <bold>Fallback sequence on violation.</bold>
                  The scheduler (1) stops accepting new production reservoir traffic; (2) completes or invalidates the current measurement according to the instruction’s execution class; (3) resets/reseeds the reservoir; (4) optionally reduces the configured gain/pump parameter within the manifest’s characterised range; (5) reruns characterisation (drift-check); (6) otherwise raises CS.PHYSOPT.NOTAVAIL and falls back to CMOS.
                  <bold>Numerical values.</bold>
                  <inline-formula>
                    <mml:math>
                      <mml:mrow>
                        <mml:msub>
                          <mml:mi>W</mml:mi>
                          <mml:mi>L</mml:mi>
                        </mml:msub>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                  ,
                  <inline-formula>
                    <mml:math>
                      <mml:mrow>
                        <mml:mi>Δ</mml:mi>
                        <mml:msub>
                          <mml:mi>t</mml:mi>
                          <mml:mi>s</mml:mi>
                        </mml:msub>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                  ,
                  <inline-formula>
                    <mml:math>
                      <mml:mrow>
                        <mml:msub>
                          <mml:mi>u</mml:mi>
                          <mml:mi>λ</mml:mi>
                        </mml:msub>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                  , and the initial
                  <inline-formula>
                    <mml:math>
                      <mml:mrow>
                        <mml:msub>
                          <mml:mi>λ</mml:mi>
                          <mml:mrow>
                            <mml:mtext>fuse</mml:mtext>
                          </mml:mrow>
                        </mml:msub>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                  are
                  <bold>configuration paramete</bold>
                  <bold>rs</bold>
                  established during P3characterisation,
                  <bold>not</bold>
                  measurements. The production image stores the resulting values alongside P3_lyapunov_ceiling in the CS.PHYSOPT manifest. Initial characterisation defaults are engineering starting values, not yet experimentally validated (status T).
                </td>
              </tr>
            </tbody>
          </table>
        </table-wrap>
      </sec>
      <sec id="sec7dot5">
        <title>7.5. P3 Target Metrics</title>
        <table-wrap id="tbl12">
          <label>Table 12</label>
          <table>
            <tbody>
              <tr>
                <td>
                  <bold>Metric</bold>
                </td>
                <td>
                  <bold>Value</bold>
                </td>
                <td>
                  <bold>Basis</bold>
                </td>
                <td>
                  <bold>Status</bold>
                </td>
              </tr>
              <tr>
                <td>Reservoir nodes</td>
                <td>≥100</td>
                <td>SOA/SRR loop target</td>
                <td>
                  <bold>T</bold>
                </td>
              </tr>
              <tr>
                <td>Update rate</td>
                <td>GHz-class</td>
                <td>
                  microring linewidth [
                  <xref ref-type="bibr" rid="B14">14</xref>
                  ]
                </td>
                <td>
                  <bold>A</bold>
                </td>
              </tr>
              <tr>
                <td>Trained parameters</td>
                <td>
                  only
                  <inline-formula>
                    <mml:math>
                      <mml:mrow>
                        <mml:msub>
                          <mml:mi>W</mml:mi>
                          <mml:mrow>
                            <mml:mtext>out</mml:mtext>
                          </mml:mrow>
                        </mml:msub>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                </td>
                <td>reservoir-computing standard</td>
                <td>
                  <bold>A</bold>
                </td>
              </tr>
              <tr>
                <td>Nonlinearity</td>
                <td>
                  Kerr
                  <italic>χ</italic>
                  (3), saturable SOA
                </td>
                <td>photonic implementations</td>
                <td>
                  <bold>A</bold>
                </td>
              </tr>
              <tr>
                <td>Mackey-Glass NRMSE</td>
                <td>&lt;0.1</td>
                <td>falsification threshold (Section 22)</td>
                <td>
                  <bold>T</bold>
                </td>
              </tr>
              <tr>
                <td>
                  <inline-formula>
                    <mml:math>
                      <mml:mrow>
                        <mml:msub>
                          <mml:mi>λ</mml:mi>
                          <mml:mn>1</mml:mn>
                        </mml:msub>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                  trust ceiling
                </td>
                <td>
                  fuse-locked
                  <inline-formula>
                    <mml:math>
                      <mml:mrow>
                        <mml:msub>
                          <mml:mi>λ</mml:mi>
                          <mml:mrow>
                            <mml:mtext>fuse</mml:mtext>
                          </mml:mrow>
                        </mml:msub>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                </td>
                <td>operator-set at BIOS</td>
                <td>
                  <bold>T</bold>
                </td>
              </tr>
            </tbody>
          </table>
        </table-wrap>
      </sec>
    </sec>
    <sec id="sec8">
      <title>8. P4 · Phononic Substrate</title>
      <sec id="sec8dot1">
        <title>8.1. Physical Basis</title>
        <p>Diamond phononic crystal with 50 - 70 GHz bandgap and Q &gt; 105 target. The phononic-bandgap-shielded acoustic-resonator concept is anchored to MacCabe <italic>et</italic><italic>al</italic>. (2020) [<xref ref-type="bibr" rid="B15">15</xref>], which reported a 5 GHz silicon cavity with Q ≈ 5 × 10<sup>10</sup> and 1.5 s phonon lifetime; CHAINSTATE-X Section 8targets the 50 - 70 GHz diamond variant (status T; Section 21.1 R4 falsification threshold applies). Phononic modes are quantised mechanical excitations that couple to the photonic layer through optomechanical interfaces (radiation-pressure coupling and cavity-enhanced phonon-photon scattering).</p>
      </sec>
      <sec id="sec8dot2">
        <title>8.2. Optomechanical Cross-Substrate Coupling</title>
        <p>Optomechanical coupling connects P4 to P1/P3 through a shared cavity mode; phonon populations modulate the cavity optical frequency, and photonic drives populate specific phonon modes. This provides a thermodynamically slower channel for states that must persist across reservoir resets.</p>
      </sec>
      <sec id="sec8dot3">
        <title>8.3. CS.* Mapping</title>
        <p>P4 exposes CS.PHYS (18 × phonon relaxation), CS.CFIELD (curved-space phonon transport), CS.CMTS (cross-medium transduction), and CS.SENTRY (vibration-based tamper detection).</p>
      </sec>
      <sec id="sec8dot4">
        <title>8.4. P4 Target Metrics</title>
        <table-wrap id="tbl13">
          <label>Table 13</label>
          <table>
            <tbody>
              <tr>
                <td>
                  <bold>Metric</bold>
                </td>
                <td>
                  <bold>Value</bold>
                </td>
                <td>
                  <bold>Basis</bold>
                </td>
                <td>
                  <bold>Status</bold>
                </td>
              </tr>
              <tr>
                <td>Bandgap centre</td>
                <td>50 - 70 GHz</td>
                <td>
                  diamond phononic literature [
                  <xref ref-type="bibr" rid="B15">15</xref>
                  ]
                </td>
                <td>
                  <bold>A</bold>
                </td>
              </tr>
              <tr>
                <td>Q factor</td>
                <td>&gt;105</td>
                <td>
                  cited phononic-bandgap cavity [
                  <xref ref-type="bibr" rid="B15">15</xref>
                  ]
                </td>
                <td>
                  <bold>A</bold>
                </td>
              </tr>
              <tr>
                <td>Feature size</td>
                <td>20 nm</td>
                <td>e-beam lithography</td>
                <td>
                  <bold>T</bold>
                </td>
              </tr>
              <tr>
                <td>Optomechanical coupling</td>
                <td>cavity-shared with P1/P3</td>
                <td>reference optomechanical devices</td>
                <td>
                  <bold>A</bold>
                </td>
              </tr>
              <tr>
                <td>Phonon-relaxation speedup</td>
                <td>18×</td>
                <td>characterisation target</td>
                <td>
                  <bold>T</bold>
                </td>
              </tr>
            </tbody>
          </table>
        </table-wrap>
      </sec>
    </sec>
    <sec id="sec9">
      <title>9. P5 · Thermodynamic and Memristive Persistent State</title>
      <sec id="sec9dot1">
        <title>9.1. Physical Basis</title>
        <p>HfO2memristive crossbar delivers persistent physical state with 106 analog levels per cell and 10 yr retention. Entropy-production channel <inline-formula><mml:math><mml:mrow><mml:mover accent="true"><mml:mi> S </mml:mi><mml:mo> ˙ </mml:mo></mml:mover><mml:mo> ≥ </mml:mo><mml:mn> 0 </mml:mn></mml:mrow></mml:math></inline-formula> published per instruction; heat flux <inline-formula><mml:math><mml:mrow><mml:msub><mml:mi> J </mml:mi><mml:mi> q </mml:mi></mml:msub><mml:mo> ⋅ </mml:mo><mml:mrow><mml:mrow><mml:mo> ∇ </mml:mo><mml:mi> T </mml:mi></mml:mrow><mml:mo> / </mml:mo><mml:mrow><mml:msub><mml:mi> T </mml:mi><mml:mn> 2 </mml:mn></mml:msub></mml:mrow></mml:mrow></mml:mrow></mml:math></inline-formula> feeds the CS.PHYSOPT scheduler’s thermodynamic cost model.</p>
      </sec>
      <sec id="sec9dot2">
        <title>9.2. CS.* Mapping</title>
        <p>P5 executes CS.PROV persistent-provenance state, CS.ID identity registers, and CS.HUMANlong-horizon interaction memory.</p>
      </sec>
      <sec id="sec9dot3">
        <title>9.3. P5 Target Metrics</title>
        <table-wrap id="tbl14">
          <label>Table 14</label>
          <table>
            <tbody>
              <tr>
                <td>
                  <bold>Metric</bold>
                </td>
                <td>
                  <bold>Value</bold>
                </td>
                <td>
                  <bold>Basis</bold>
                </td>
                <td>
                  <bold>Status</bold>
                </td>
              </tr>
              <tr>
                <td>Analog levels per cell</td>
                <td>106</td>
                <td>STOC memristor characterisation</td>
                <td>
                  <bold>A</bold>
                </td>
              </tr>
              <tr>
                <td>Write energy</td>
                <td>nJ/write</td>
                <td>cited HfO2crossbar</td>
                <td>
                  <bold>A</bold>
                </td>
              </tr>
              <tr>
                <td>Retention</td>
                <td>10 yr</td>
                <td>cited HfO2crossbar</td>
                <td>
                  <bold>A</bold>
                </td>
              </tr>
              <tr>
                <td>Endurance target</td>
                <td>1010 cycles</td>
                <td>engineering target</td>
                <td>
                  <bold>T</bold>
                </td>
              </tr>
            </tbody>
          </table>
        </table-wrap>
      </sec>
    </sec>
    <sec id="sec10">
      <title>10. P6 · Three Independent QED-Boundary Laboratory Configurations · REVISED</title>
      <table-wrap id="tbl15">
        <label>Table 15</label>
        <table>
          <tbody>
            <tr>
              <td>
                <bold>P6 restructured as P6-A/P6-B/P6-C · mutually independent labs</bold>
                v0.1 presented Casimir, DCE, and sonoluminescence as three sub-layers of a single P6 tier, and Section 15.3 described the CHAINSTATE-P3 device as shipping all three together. That framing invited the reviewer to ask about the physical interface between P6 and the room-temperature photonic system, and left ambiguous whether the three configurations were meant to coexist.
              </td>
            </tr>
            <tr>
              <td>
                v0.2 restates the three as
                <bold>P6-A · Casimir MEMS cavity</bold>
                ,
                <bold>P6-B · superconducting D</bold>
                <bold>CE laboratory</bold>
                , and
                <bold>P6-C · sonoluminescence reservoir</bold>
                . Each is a
                <bold>mutually independent experimental</bold>
                <bold>configuration</bold>
                . None of the three is assumed to coexist with the others in a production system, and none is claimed as a compute-power source.Section 15 device-family language updated in parallel: P3 is now described as
                <italic>the first researc</italic>
                <italic>h-grade host capable of interfacing to external P4/P6 laboratory modules</italic>
                , not as a device that ships P4 + P6 together.
              </td>
            </tr>
          </tbody>
        </table>
      </table-wrap>
      <sec id="sec10dot1">
        <title>10.1. P6-A · Casimir MEMS Cavity</title>
        <p><bold>Purpose.</bold>Tunable boundary condition, cavity-mode selection, nanomechanical sensing, ultra-small force sensing.</p>
        <p><bold>Configuratio</bold><bold>n.</bold>Room-temperature photonic PIC → optical probe/coupler → tunable Casimir cavity with MEMS gap actuator → optical readout at the photonic layer. A parallel capacitive MEMS readout feeds the control-side ADC. The Casimir force between ideal parallel plates is <inline-formula><mml:math><mml:mrow><mml:mrow><mml:mi> F </mml:mi><mml:mo> / </mml:mo><mml:mi> A </mml:mi></mml:mrow><mml:mo> = </mml:mo><mml:mo> − </mml:mo><mml:mrow><mml:mrow><mml:mi> π </mml:mi><mml:mn> 2 </mml:mn><mml:mi> ℏ </mml:mi><mml:mi> c </mml:mi></mml:mrow><mml:mo> / </mml:mo><mml:mrow><mml:mrow><mml:mo> ( </mml:mo><mml:mrow><mml:mn> 240 </mml:mn><mml:msub><mml:mi> d </mml:mi><mml:mn> 4 </mml:mn></mml:msub></mml:mrow><mml:mo> ) </mml:mo></mml:mrow></mml:mrow></mml:mrow></mml:mrow></mml:math></inline-formula> ; Lifshitz theory handles the realistic material case [<xref ref-type="bibr" rid="B16">16</xref>]-[<xref ref-type="bibr" rid="B18">18</xref>].</p>
        <p><bold>Interfa</bold><bold>ce to the room-temperature photonic system.</bold>The MEMS cavity attaches to a dedicated experimental port on the photonic PIC. Optical probe light couples in, cavity-modulated light couples out, and the MEMS gap actuator is driven by the control-side ADC/DAC pair. Nothing in P6-A enters the P1/P2/P3 compute fabric as decision-tagged evidence.</p>
        <p><bold>Status.</bold>Physically removable module. Not on the CHAINSTATE-P1 or CHAINSTATE-P2 commercial base variants. Never accepted as evidence for any decision-tagged retirement.</p>
      </sec>
      <sec id="sec10dot2">
        <title>10.2. P6-B · Superconducting DCE Laboratory</title>
        <p><bold>Purpose.</bold> Dynamic Casimir effect (DCE) research—generation of photons from vacuum by rapid boundary-condition modulation. Anchored to the 2011 Nature demonstration [<xref ref-type="bibr" rid="B19">19</xref>].</p>
        <p><bold>Config</bold><bold>uration.</bold>A <bold>cryogenic laboratory configuration</bold>, not a room-temperature photonic compute substrate. The DCE process is hosted on a superconducting circuit with RF boundary modulation and observed as two-mode squeezed radiation.</p>
        <p><bold>Interfa</bold><bold>ce to the room-temperature photonic system.</bold>Room-temperature control electronics → RF/microwave drive chain → cryogenic superconducting circuit → microwave/photonic measurement chain → room-temperature ADC/data-acquisition interface. <bold>DCE-generated photons never enter the P1/P2/P3 compute</bold><bold>fabric</bold>and are never accepted as decision-tagged evidence: the CS.PHYSOPT scheduler enforces this by an epistemic-class check at dispatch.</p>
        <disp-formula id="FD3">
          <mml:math display="inline">
            <mml:mrow>
              <mml:mtext>akout</mml:mtext>
              <mml:mo>=</mml:mo>
              <mml:mi>α</mml:mi>
              <mml:mtext>k</mml:mtext>
              <mml:mo>⋅</mml:mo>
              <mml:mtext>akin</mml:mtext>
              <mml:mo>+</mml:mo>
              <mml:mi>β</mml:mi>
              <mml:mtext>k</mml:mtext>
              <mml:mo>⋅</mml:mo>
              <mml:mrow>
                <mml:mo>(</mml:mo>
                <mml:mrow>
                  <mml:mtext>akin</mml:mtext>
                </mml:mrow>
                <mml:mo>)</mml:mo>
              </mml:mrow>
              <mml:mo>†</mml:mo>
              <mml:mtext>
                 
              </mml:mtext>
              <mml:mtext>
                 
              </mml:mtext>
              <mml:mtext>with</mml:mtext>
              <mml:mtext>
                 
              </mml:mtext>
              <mml:mtext>nk</mml:mtext>
              <mml:mo>=</mml:mo>
              <mml:mrow>
                <mml:mo>|</mml:mo>
                <mml:mrow>
                  <mml:mi>β</mml:mi>
                  <mml:mtext>k</mml:mtext>
                </mml:mrow>
                <mml:mo>|</mml:mo>
              </mml:mrow>
              <mml:mn>2</mml:mn>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p><bold>Status.</bold>Laboratory configuration only. Never on the P1 or P2 commercial base variants. Never on a shared compute die.</p>
      </sec>
      <sec id="sec10dot3">
        <title>10.3. P6-C · Sonoluminescence Reservoir</title>
        <p><bold>Purpose.</bold>Investigation of the collapsing bubble as a novel physical reservoir; anchored to the single-bubble sonoluminescence literature [<xref ref-type="bibr" rid="B20">20</xref>]. Bubble dynamics are exquisitely nonlinear, so the programme asks whether the collapsing bubble’s optical spectrum constitutes a useful nonlinear reservoir that differs from the SOA-loop reservoir of Section 7.</p>
        <p><bold>Configura</bold><bold>tion.</bold>Benchtop laboratory module: liquid cell (degassed water or D<sub>2</sub>O) + piezoelectric ultrasonic transducer + single-bubble stabilization optics + high-speed spectrometer/photodetector.</p>
        <p><bold>Interfa</bold><bold>ce to the room-temperature photonic system.</bold>Liquid cell + piezo ultrasonic transducer + bubble-stabilisation optics + spectrometer/photodetector → optical fibre/PIC interface → room-temperature measurement/control system. The PIC does <bold>not</bold>host the liquid cell; the coupling is through a dedicated fibre feed.</p>
        <p><bold>Status.</bold>Research programme with a clear falsification criterion—either the reservoir’s output scores correlate with useful CS.* classifications or they do not (Section 22.4). Never on the P1 or P2 commercial base variants.</p>
      </sec>
      <sec id="sec10dot4">
        <title>10.4. P6 Discipline · Mutually Independent, Never Coexisting</title>
        <p>P6-A, P6-B, and P6-C are <bold>mutually independent experimental configurati</bold><bold>ons</bold>. None of the three is required to be present for the others to function. They are <bold>not assum</bold><bold>ed to coexist in a production system</bold>. The variant matrix (Section 15.6) reflects this explicitly. The phrase “P6 substrate” is retired; only the three sub-configurations are referenced in v0.2.</p>
      </sec>
    </sec>
    <sec id="sec11">
      <title>11. Eigenmode-Selective Computation as First-Class ISA</title>
      <sec id="sec11dot1">
        <title>11.1. The Mathematical Framing</title>
        <p>Every physical substrate has structured eigenmodes: optical cavity resonances, phononic-crystal band gap edges, OEO limit-cycle phase attractors. CHAINSTATE-X exposes these eigenmodes as first-class ISA objects—instructions that select, suppress, or couple specific eigenmodes execute in a compact number of cycles rather than requiring full-mesh reprogramming.</p>
      </sec>
      <sec id="sec11dot2">
        <title>11.2. Eigenbasis Geometry</title>
        <p>The compiler chooses a substrate-appropriate eigenbasis at EL-IR emission time. Photonic eigenmodes are labelled by (<italic>λ</italic>, <italic>m</italic>); phononic eigenmodes by (<italic>Ω</italic>, <italic>k</italic>); OEO eigenmodes by phase attractor <inline-formula><mml:math><mml:mrow><mml:mi> s </mml:mi><mml:mo> ∈ </mml:mo><mml:mrow><mml:mo> { </mml:mo><mml:mrow><mml:mn> 0 </mml:mn><mml:mo> , </mml:mo><mml:mi> π </mml:mi></mml:mrow><mml:mo> } </mml:mo></mml:mrow></mml:mrow></mml:math></inline-formula> .</p>
      </sec>
      <sec id="sec11dot3">
        <title>11.3. Cross-Substrate Eigenmode Transport</title>
        <p>The CS.PHYSOPT.MODE.COUPLE instruction moves state between eigenbases on adjacent substrates (photonic → phononic, phononic → OEO). Transport fidelity is bounded by the interface’s transduction budget and is published as part of the substrate manifest.</p>
      </sec>
    </sec>
    <sec id="sec12">
      <title>12. The Photonic State Vector and ISA Exposure</title>
      <sec id="sec12dot1">
        <title>12.1. The State Vector</title>
        <p>The 14 scalar state variables of Section 3.2 map to ISA-visible operands. <inline-formula><mml:math display="inline"><mml:mrow><mml:mi> Λ </mml:mi><mml:mo> = </mml:mo><mml:mrow><mml:mo> ( </mml:mo><mml:mrow><mml:mi> λ </mml:mi><mml:mo> , </mml:mo><mml:mi> φ </mml:mi><mml:mo> , </mml:mo><mml:mi> p </mml:mi><mml:mo> , </mml:mo><mml:mi> m </mml:mi><mml:mo> , </mml:mo><mml:mi> t </mml:mi><mml:mo> , </mml:mo><mml:mi> T </mml:mi><mml:mo> , </mml:mo><mml:mi> B </mml:mi><mml:mo> , </mml:mo><mml:mi> E </mml:mi><mml:mo> , </mml:mo><mml:mi> μ </mml:mi><mml:mo> , </mml:mo><mml:mi> ε </mml:mi><mml:mo> , </mml:mo><mml:mi> d </mml:mi><mml:mo> , </mml:mo><mml:mi> J </mml:mi><mml:mo> , </mml:mo><mml:mi> κ </mml:mi><mml:mo> , </mml:mo><mml:mi> Ω </mml:mi></mml:mrow><mml:mo> ) </mml:mo></mml:mrow></mml:mrow></mml:math></inline-formula> . Every CS.PHYSOPT instruction accepts a subset of <italic>Λ</italic> as its operand vector, allowing the compiler to program the substrate at the physical-parameter level.</p>
      </sec>
      <sec id="sec12dot2">
        <title>12.2. Polarisation as Computational Channel</title>
        <p>TE and TM polarisation states multiply the channel count per waveguide by 2. Polarisation is exposed to software as the state variable p.</p>
      </sec>
      <sec id="sec12dot3">
        <title>12.3. Wavelength-Division Multiplexing</title>
        <table-wrap id="tbl16">
          <label>Table 16</label>
          <table>
            <tbody>
              <tr>
                <td>
                  <bold>Channel-count vs transformation-rank separation · third occurrence</bold>
                  16 WDM channels on the C-band grid (1530 - 1565 nm at 200 GHz spacing) carry 16 independent scalar elements per waveguide. Combined with 2 polarisations (TE/TM), each waveguide carries 32 independent scalars simultaneously. The 128 × 128 mesh’s aggregate multiplexed channel count becomes 128 × 32 = 4096; adding
                  <bold>2 independent</bold>
                  <bold>spatial modes (LP0,1 and LP1,1)</bold>
                  gives
                  <bold>2 polarisations</bold>
                  <bold>×</bold>
                  <bold>2 spatialmodes</bold>
                  <bold>×</bold>
                  <bold>16</bold>
                  <bold>wavelengths</bold>
                  <bold>×</bold>
                  <bold>128 waveguides = 8192 aggregate multiplexed channel opportunities</bold>
                  .
                  <bold>8192 is the aggregate multiplexed channel-opportunity count, not the rank of the</bold>
                  <bold>programmable linear transformation.</bold>
                  The dense-transform dimension is
                  <inline-formula>
                    <mml:math>
                      <mml:mrow>
                        <mml:msub>
                          <mml:mi>N</mml:mi>
                          <mml:mrow>
                            <mml:mtext>mesh</mml:mtext>
                          </mml:mrow>
                        </mml:msub>
                        <mml:mo>=</mml:mo>
                        <mml:mn>128</mml:mn>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                  per independently configured wavelength/polarisation/mode block. For a single 128 × 128 mesh block, rank (W) ≤ 128. Same clarification appears in Section 5.4 and Section 5.7.
                </td>
              </tr>
            </tbody>
          </table>
        </table-wrap>
      </sec>
      <sec id="sec12dot4">
        <title>12.4. Temporal-Mode Encoding</title>
        <p>Time-bin encoding assigns each pulse to a temporal slot, giving temporal-mode multiplexing orthogonal to wavelength, polarisation, and spatial mode. The 1 GHz photodetector rate of P1 sets the smallest usable temporal slot; P3 reservoir dynamics fill the temporal-mode dimension with reservoir state.</p>
      </sec>
      <sec id="sec12dot5">
        <title>12.5. The ISA Exposure</title>
        <p>The CS.PHYSOPT.STATE.LAMBDA/PHI/P/M/T instructions expose each of the 14 state-vectorcomponents to software. The compiler assigns compile-time values that the runtime propagates to the substrate driver.</p>
      </sec>
    </sec>
    <sec id="sec13">
      <title>13. The CS.PHYSOPT Instruction Set Architecture</title>
      <sec id="sec13dot1">
        <title>13.1. Encoding</title>
        <p>CS.PHYSOPT uses the RISC-V custom-1 opcode (0101011) with the sub-op field selecting family and operation. See Paper XVII Section 5 for the base CS.* encoding envelope.</p>
      </sec>
      <sec id="sec13dot2">
        <title>13.2. The Ten Families</title>
        <p>PHYSOPT.LINEAR (P1) · PHYSOPT.ISING (P2) · PHYSOPT.RESERVOIR (P3) · PHYSOPT.PHONON (P4) ·PHYSOPT.MEMRIST (P5) · PHYSOPT.CAVITY (P6-A) · PHYSOPT.DCE (P6-B) · PHYSOPT.SONOLUM (P6-C)· PHYSOPT.MODE (cross-substrate eigenmode transport) · PHYSOPT.STATE (14-variable state-vectoraccess).</p>
      </sec>
      <sec id="sec13dot3">
        <title>13.3. Semantic Conventions</title>
        <p>Every instruction carries an epistemic class ∈ {DECISION, MEASUREMENT, RESEARCH, DIAGNOSTIC}. Only DECISION-class instructions reach the ALLOW gate and produce a signed retirement receipt. RESEARCH-class instructions execute in a physically isolated resource envelope and their results are excluded from downstream decision-tagged operations by construction.</p>
      </sec>
      <sec id="sec13dot4">
        <title>13.4. Full Instruction Reference (Excerpt)</title>
        <p>Selected instructions—the complete reference is archived to the public Base 8453 anchor.</p>
        <table-wrap id="tbl17">
          <label>Table 17</label>
          <table>
            <tbody>
              <tr>
                <td>
                  <bold>Mnemonic</bold>
                </td>
                <td>
                  <bold>Operands</bold>
                </td>
                <td>
                  <bold>Meaning</bold>
                </td>
              </tr>
              <tr>
                <td>PHYSOPT.LINEAR.APPLY</td>
                <td>rs1, rs2, rd</td>
                <td>
                  apply mesh
                  <inline-formula>
                    <mml:math display="inline">
                      <mml:mrow>
                        <mml:mi>U</mml:mi>
                        <mml:mrow>
                          <mml:mo>(</mml:mo>
                          <mml:mrow>
                            <mml:mi>φ</mml:mi>
                            <mml:mo>,</mml:mo>
                            <mml:mi>κ</mml:mi>
                          </mml:mrow>
                          <mml:mo>)</mml:mo>
                        </mml:mrow>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                  to
                  <inline-formula>
                    <mml:math display="inline">
                      <mml:mrow>
                        <mml:msub>
                          <mml:mi>E</mml:mi>
                          <mml:mrow>
                            <mml:mtext>in</mml:mtext>
                          </mml:mrow>
                        </mml:msub>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                </td>
              </tr>
              <tr>
                <td>PHYSOPT.ISING.SETJ</td>
                <td>rs1, rs2</td>
                <td>
                  load coupling matrix
                  <inline-formula>
                    <mml:math>
                      <mml:mrow>
                        <mml:msub>
                          <mml:mi>J</mml:mi>
                          <mml:mrow>
                            <mml:mi>i</mml:mi>
                            <mml:mi>j</mml:mi>
                          </mml:mrow>
                        </mml:msub>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                </td>
              </tr>
              <tr>
                <td>PHYSOPT.ISING.SETTLE</td>
                <td>rd</td>
                <td>
                  OPO settle → measure
                  <inline-formula>
                    <mml:math>
                      <mml:mover accent="true">
                        <mml:mi>s</mml:mi>
                        <mml:mo>^</mml:mo>
                      </mml:mover>
                    </mml:math>
                  </inline-formula>
                </td>
              </tr>
              <tr>
                <td>PHYSOPT.RESERVOIR.INJECT</td>
                <td>rs1</td>
                <td>
                  amplitude-modulate
                  <italic>u</italic>
                  (
                  <italic>t</italic>
                  ) into reservoir
                </td>
              </tr>
              <tr>
                <td>PHYSOPT.RESERVOIR.READOUT</td>
                <td>rd</td>
                <td>
                  read reservoir state
                  <inline-formula>
                    <mml:math>
                      <mml:mover accent="true">
                        <mml:mi>x</mml:mi>
                        <mml:mo>^</mml:mo>
                      </mml:mover>
                    </mml:math>
                  </inline-formula>
                </td>
              </tr>
              <tr>
                <td>PHYSOPT.PHONON.COUPLE</td>
                <td>rs1, rs2</td>
                <td>couple optomechanical mode</td>
              </tr>
              <tr>
                <td>PHYSOPT.MEMRIST.WRITE</td>
                <td>rs1, rs2</td>
                <td>write analog value to crossbar</td>
              </tr>
              <tr>
                <td>PHYSOPT.CAVITY.DCE_MODULATE</td>
                <td>rs1, tag</td>
                <td>P6-B research modulation</td>
              </tr>
              <tr>
                <td>PHYSOPT.CAVITY.SONOLUM</td>
                <td>rs1, tag</td>
                <td>P6-C sub-variant only</td>
              </tr>
              <tr>
                <td>PHYSOPT.MODE.SELECT</td>
                <td>
                  <italic>λ</italic>
                  i, tag
                </td>
                <td>eigenmode select</td>
              </tr>
              <tr>
                <td>PHYSOPT.MODE.SUPPRESS</td>
                <td>
                  <italic>λ</italic>
                  i, tag
                </td>
                <td>eigenmode suppress</td>
              </tr>
              <tr>
                <td>PHYSOPT.MODE.COUPLE</td>
                <td>
                  <italic>λ</italic>
                  i,
                  <italic>λ</italic>
                  j
                </td>
                <td>couple eigenmodes</td>
              </tr>
              <tr>
                <td>PHYSOPT.MODE.QUERY</td>
                <td>
                  <italic>λ</italic>
                  i, rd
                </td>
                <td>amplitude → rd</td>
              </tr>
              <tr>
                <td>PHYSOPT.STATE.LAMBDA</td>
                <td>rs1</td>
                <td>
                  set
                  <italic>λ</italic>
                  (wavelength)
                </td>
              </tr>
            </tbody>
          </table>
        </table-wrap>
      </sec>
    </sec>
    <sec id="sec14">
      <title>14. RISC-V Interface and Compiler Pipeline · Two Execution Gates · REVISED</title>
      <p>The RISC-V executive of CHAINSTATE-X is the Paper XVII Section 3 executive plus a CS.PHYSOPT decoder plus a physical-substrate scheduler. Software above the executive sees CS.PHYSOPT as a normal CS.* extension: LLVM emits CS.PHYSOPT instructions from a set of intrinsics, the runtime dispatches them, and the fabric returns results through the retirement checkpoint of Gate B below.</p>
      <table-wrap id="tbl18">
        <label>Table 18</label>
        <table>
          <tbody>
            <tr>
              <td>
                <bold>Two-gate execution model resolves the Section 14</bold>
                <bold>↔</bold>
                <bold>Section 22.1 contradiction</bold>
                v0.1 Section 14 stage 4 called itself “retirement checkpoint” while Section 22.1 asserted that formal-verification properties require every instruction to reach retirement
                <italic>before</italic>
                any physical execution begins. The two statements are incompatible under a single meaning of “retirement”. v0.2 defines two distinct gates and reserves’ retirement’ exclusively for the post-verification gate.
                <bold>Gate A · Pre-execution authorization checkpoint.</bold>
                Before physical execution: Decode → EL-IR → Manifest → Deontic authorization →
                <bold>EXEC_AUTH</bold>
                → physical execution. Gate A checks substrate target, epistemic class, tolerance, safety constraints, and resource availability. Every instruction MUST pass Gate A before the fabric may begin physical execution.
                <bold>Gate</bold>
                <bold>B · Post-execution retirement checkpoint.</bold>
                After: physical execution → measurement → verification →
                <bold>RETIRE</bold>
                . Only at Gate B is the architectural state updated and the provenance receipt HMAC-signed and anchored to Base 8453.Section 22.1 SVA properties (see Section 22) are rewritten around EXEC_AUTH and RETIRE as distinct checkpoints.
              </td>
            </tr>
          </tbody>
        </table>
      </table-wrap>
      <sec id="sec14dot1">
        <title>14.1. The Compiler Pipeline · Seven Stages · v0.2</title>
        <p>Stage numbering unchanged from v0.1; stage 4 is renamed and its scope restricted to <bold>pre-execution authorization</bold>. “Retirement” now refers exclusively to stage 7.</p>
        <table-wrap id="tbl19">
          <label>Table 19</label>
          <table>
            <tbody>
              <tr>
                <td>
                  <bold>Stage</bold>
                </td>
                <td>
                  <bold>Name</bold>
                </td>
                <td>
                  <bold>Content</bold>
                </td>
              </tr>
              <tr>
                <td>1</td>
                <td>Source</td>
                <td>
                  CS.* runtime call · e.g. cs_attn(
                  <italic>Q</italic>
                  ,
                  <italic>K</italic>
                  ,
                  <italic>V</italic>
                  ) or cs_graph_partition(
                  <italic>G</italic>
                  )
                </td>
              </tr>
              <tr>
                <td>2</td>
                <td>LLVM intrinsic</td>
                <td>
                  e.g. @llvm.cs.attn(
                  <italic>Q</italic>
                  ,
                  <italic>K</italic>
                  ,
                  <italic>V</italic>
                  , tolerance)
                </td>
              </tr>
              <tr>
                <td>3</td>
                <td>EL-IR emission (Section 3.4)</td>
                <td>
                  (
                  <italic>J</italic>
                  ,
                  <italic>h</italic>
                  ,
                  <italic>V</italic>
                  ) + substrate hint + tolerance vector
                </td>
              </tr>
              <tr>
                <td>4</td>
                <td>
                  <bold>Pre-execution</bold>
                  <bold>authorization</bold>
                  <bold>checkpoint</bold>
                  <bold>(Gate A)</bold>
                </td>
                <td>
                  CS.PHYSOPT scheduler consults manifest; chooses substrate; verifies Deontic; costs per equation (9); emits
                  <bold>EXEC_AUTH</bold>
                  decision before any physical execution begins
                </td>
              </tr>
              <tr>
                <td>5</td>
                <td>Substrate driver</td>
                <td>
                  set
                  <inline-formula>
                    <mml:math display="inline">
                      <mml:mrow>
                        <mml:mi>Λ</mml:mi>
                        <mml:mo>=</mml:mo>
                        <mml:mrow>
                          <mml:mo>(</mml:mo>
                          <mml:mrow>
                            <mml:mi>λ</mml:mi>
                            <mml:mo>,</mml:mo>
                            <mml:mi>φ</mml:mi>
                            <mml:mo>,</mml:mo>
                            <mml:mi>p</mml:mi>
                            <mml:mo>,</mml:mo>
                            <mml:mi>m</mml:mi>
                            <mml:mo>,</mml:mo>
                            <mml:mi>t</mml:mi>
                            <mml:mo>,</mml:mo>
                            <mml:mi>T</mml:mi>
                            <mml:mo>,</mml:mo>
                            <mml:mi>B</mml:mi>
                            <mml:mo>,</mml:mo>
                            <mml:mi>E</mml:mi>
                            <mml:mo>,</mml:mo>
                            <mml:mi>μ</mml:mi>
                            <mml:mo>,</mml:mo>
                            <mml:mi>ε</mml:mi>
                            <mml:mo>,</mml:mo>
                            <mml:mi>d</mml:mi>
                            <mml:mo>,</mml:mo>
                            <mml:mi>J</mml:mi>
                            <mml:mo>,</mml:mo>
                            <mml:mi>κ</mml:mi>
                            <mml:mo>,</mml:mo>
                            <mml:mi>Ω</mml:mi>
                          </mml:mrow>
                          <mml:mo>)</mml:mo>
                        </mml:mrow>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                </td>
              </tr>
              <tr>
                <td>6</td>
                <td>Physical execution</td>
                <td>light propagates through mesh; OEO settles; reservoir evolves; phonon transfers; memristor writes</td>
              </tr>
              <tr>
                <td>7</td>
                <td>
                  <bold>Measure + verify +</bold>
                  <bold>retirement</bold>
                  <bold>checkpoint (GateB)</bold>
                </td>
                <td>
                  photodetect; ADC; RISC-V verifier; provenance HMAC receipt; Base8453 anchor;
                  <bold>RETIRE</bold>
                  —architectural state update
                </td>
              </tr>
            </tbody>
          </table>
        </table-wrap>
      </sec>
      <sec id="sec14dot2">
        <title>14.2. The Manifest</title>
        <p>The runtime physical-substrate manifest is populated at BIOS from a fuse-locked device-inventory ROM and carries per-substrate calibration, trust-region parameters (Section 7.4), authorised epistemic-class list, and substrate availability. The manifest is one of Gate A’s inputs.</p>
      </sec>
      <sec id="sec14dot3">
        <title>14.3. Software-Visible Interface</title>
        <p>Software sees a normal CS.* dispatch envelope. The two-gate structure is invisible to application code except through the provenance receipt returned at RETIRE, which carries the EXEC_AUTH decision hash from Gate A.</p>
      </sec>
      <sec id="sec14dot4">
        <title>14.4. Provenance Receipts Include Substrate ID and Both Gate Hashes</title>
        <p>Every retirement receipt now carries: substrate ID; EXEC_AUTH decision hash from Gate A; measurement result; verification result; HMAC over the combined structure; Base 8453 anchor txhash. This is the substrate’s canonical audit artefact.</p>
      </sec>
    </sec>
    <sec id="sec15">
      <title>15. Device Family · REVISED Variant Language</title>
      <table-wrap id="tbl20">
        <label>Table 20</label>
        <table>
          <tbody>
            <tr>
              <td>
                <bold>P3/P6 device-family language corrected</bold>
                v0.1 Section 15.3 described CHAINSTATE-P3 as the
                <italic>first variant to ship P4 phononic + P6 QED experimental modules</italic>
                . Taken with the Section 10 P6 revisions (P6-A/P6-B/P6-C as three mutually independent laboratory configurations), that phrasing became inconsistent.v0.2 uses this language throughout Section 15:
                <bold>P3 is the first research-grade host capable of i</bold>
                <bold>nterfacing to external P4/P6 laboratory modules. P6-A, P6-B, and P6-C are mutually</bold>
                <bold>in</bold>
                <bold>dependent experimental configurations and are not assumed to coexist in a production s</bold>
                <bold>ystem.</bold>
                The variant matrix reflects this: no shipped device asserts all three P6 configurations simultaneously.
              </td>
            </tr>
          </tbody>
        </table>
      </table-wrap>
      <sec id="sec15dot1">
        <title>15.1. CHAINSTATE-P1 · Commercial Linear-Photonic Accelerator</title>
        <p><bold>Positionin</bold><bold>g.</bold>Entry-level commercial device. First shipping variant. Direct commercial competitor to Lightelligence PACE2, Lightmatter Envise, Salience Labs’ TDM engine—all built on the MZI-mesh + electronic-nonlinear architecture of [<xref ref-type="bibr" rid="B3">3</xref>]-[<xref ref-type="bibr" rid="B5">5</xref>]. <bold>Physi</bold><bold>cal.</bold> P0 (co-packaged optics) + P1 (128 × 128 MZI mesh, WDM, TE/TM polarisation) + Paper XVII CHAINSTATE-1 fabric die as companion. P2 - P6 all disabled. <bold>Package.</bold> Full-height double-width PCIe 5 card, 200 W TDP, external laser input, 128 optical I/O fibres. <bold>ASP.</bold>USD 6000 - 9000. <bold>Shipping.</bold> Q3 2028: first commercial samples. <bold>Foundry.</bold>AIM Photonics SiN low-loss + TSMC N4/N3E for CS.* die.</p>
      </sec>
      <sec id="sec15dot2">
        <title>15.2. CHAINSTATE-P2 · Optimisation-Focused SoC</title>
        <p><bold>Positioning.</bold>Adds Ising/reservoir substrates on top of P1. Targets combinatorial-optimisation buyers. Competes with D-Wave Advantage2, Fujitsu Digital Annealer, Toshiba SBM, Light Solver. <bold>Physical.</bold>P0 + P1 + P2 (256 fully-connected/41 k sparse Ising) + P3 (100-node OPO reservoir) + P5 (memristor persistence) + CS.* fabric die. P4 and all P6-A/B/C disabled. <bold>Package.</bold>Full-height double-width PCIe 5 card, 300 W TDP. <bold>ASP.</bold> USD 15,000 - 22,000. <bold>Shipping.</bold> Q1 2029. <bold>Foundry.</bold> AIMPhotonics + imec III-V heterogeneous + TSMC N3E.</p>
      </sec>
      <sec id="sec15dot3">
        <title>15.3. CHAINSTATE-P3 · Research-Grade Transmedium Host · REVISED Language</title>
        <table-wrap id="tbl21">
          <label>Table 21</label>
          <table>
            <tbody>
              <tr>
                <td>
                  <bold>P3 as host, not integrated QED device</bold>
                  <bold>Positioning.</bold>
                  Research + government + defence + sovereign-compute buyer.
                  <bold>The first</bold>
                  <bold>research-grade host capable of interfacing to external P4 phononic and P6 laboratory modules.</bold>
                  P3 does not ship all P6 configurations simultaneously; the customer selects at most one of P6-A/P6-B/P6-C, and each of the three configurations arrives as a separately attached module.
                  <bold>Physical.</bold>
                  P0 + P1 + P2 + P3 + P4 (diamond phononic crystal with 50 - 70 GHz bandgap) + P5 +
                  <bold>o</bold>
                  <bold>ne</bold>
                  of {P6-A Casimir cavity, P6-B DCE research port, P6-C sonoluminescence module}—customer-selected. CS.* fabric die included.
                  <bold>Package.</bold>
                  4U rack unit; requires 2 kW cooling; separately-cooled phononic + Casimir sections. P6-Bcryogenic laboratory configuration requires an external dilution- refrigerator envelope not included in the rack.
                  <bold>ASP.</bold>
                  USD 180,000 - 350,000 depending on P6-A/B/C selection.
                  <bold>Shipping.</bold>
                  Q3 2029 first samples.
                  <bold>Foundry.</bold>
                  AIM Photonics + imec + custom diamond MEMS + Fraunhofer HHI photonic packaging.
                </td>
              </tr>
            </tbody>
          </table>
        </table-wrap>
      </sec>
      <sec id="sec15dot4">
        <title>15.4. CHAINSTATE-P4 · Phononic + P6-C Sonoluminescence Research Module</title>
        <p><bold>Positioning</bold><bold>.</bold> Physics-research add-on to CHAINSTATE-P3. Not a stand-alone product. Combines theP4 phononic laboratory programme with the P6-C sonoluminescence configuration when the customer selects that P6 variant. <bold>Physica</bold><bold>l.</bold> Dedicated liquid-cell cavity with piezoelectric ultrasonic transducer array, degassed water or D2O working fluid, single-bubble stabilisation optics, high-speedspectrometer, PIC coupling. <bold>Package.</bold> Benchtop module with optical fibre coupling to CHAINSTATE-P3. <bold>ASP.</bold> USD 45,000 - 80,000 for the module (in addition to the P3 host). <bold>Shipping.</bold> 2030 in prototype form only. <bold>Foundry.</bold> Custom laboratory assembly; not fabless.</p>
      </sec>
      <sec id="sec15dot5">
        <title>15.5. CHAINSTATE-X SoC · Full Integration Flagship</title>
        <p><bold>Positioning.</bold>The fully-integrated flagship. Every commercially manufacturable physical substrateP1-P5 on a single reference board with a 2.5D-packaged CS.* fabric die. <bold>Optional</bold>external attach of exactly one of P6-A, P6-B, or P6-C. <bold>Physical.</bold> P0-P5 all present; P6 optional external attach (one ofA/B/C only); CHAINSTATE-1 CS.* fabric die (Paper XVII, 550 - 700 mm2TSMC N3E) bonded as a 2.5 D companion on a shared silicon interposer; HBM3E stacks × 2 for 48 GB working memory; CoWoS-L packaging. <bold>Package.</bold> Full-height double-width PCIe 5 card, 350 - 400 W TDP, active liquid cooling. <bold>ASP.</bold> USD 45,000 - 60,000 base configuration; USD 220,000 - 480,000 with any one P6 external attach. <bold>Shipping.</bold> Q2 2030. <bold>Foundry.</bold> TSMC N3E + AIM Photonics + imec + LioniX + IHP mixed.</p>
      </sec>
      <sec id="sec15dot6">
        <title>15.6. Variant Matrix · REVISED · P6 Column Is A/B/C Selection</title>
        <p>Column P6 now represents which single P6-A/B/C configuration is shipped, not a simultaneous ownership of all three—indicates no P6 configuration; A, B, C indicate exactly one selected.</p>
        <table-wrap id="tbl22">
          <label>Table 22</label>
          <table>
            <tbody>
              <tr>
                <td>
                  <bold>Variant</bold>
                </td>
                <td>
                  <bold>P1</bold>
                </td>
                <td>
                  <bold>P2</bold>
                </td>
                <td>
                  <bold>P3</bold>
                </td>
                <td>
                  <bold>P4</bold>
                </td>
                <td>
                  <bold>P5</bold>
                </td>
                <td>
                  <bold>P6 selection</bold>
                </td>
                <td>
                  <bold>CS.* die</bold>
                </td>
                <td>
                  <bold>First silicon</bold>
                </td>
              </tr>
              <tr>
                <td>CHAINSTATE-P1</td>
                <td>✓</td>
                <td>—</td>
                <td>—</td>
                <td>—</td>
                <td>partial</td>
                <td>—</td>
                <td>✓</td>
                <td>Q3 2028</td>
              </tr>
              <tr>
                <td>CHAINSTATE-P2</td>
                <td>✓</td>
                <td>✓</td>
                <td>✓</td>
                <td>—</td>
                <td>✓</td>
                <td>—</td>
                <td>✓</td>
                <td>Q1 2029</td>
              </tr>
              <tr>
                <td>CHAINSTATE-P3</td>
                <td>✓</td>
                <td>✓</td>
                <td>✓</td>
                <td>✓</td>
                <td>✓</td>
                <td>one of A/B/C</td>
                <td>✓</td>
                <td>Q3 2029</td>
              </tr>
              <tr>
                <td>CHAINSTATE-P4module</td>
                <td>—</td>
                <td>—</td>
                <td>—</td>
                <td>—</td>
                <td>—</td>
                <td>C only</td>
                <td>—</td>
                <td>2030</td>
              </tr>
              <tr>
                <td>CHAINSTATE-X SoC</td>
                <td>✓</td>
                <td>✓</td>
                <td>✓</td>
                <td>✓</td>
                <td>✓</td>
                <td>opt. one of A/B/C</td>
                <td>2.5 D CoWoS</td>
                <td>2030</td>
              </tr>
            </tbody>
          </table>
        </table-wrap>
      </sec>
    </sec>
    <sec id="sec16">
      <title>16. Materials Stack and Fabrication Options</title>
      <sec id="sec16dot1">
        <title>16.1. Materials-by-Layer Table</title>
        <p>Materials chosen for manufacturability at established foundries or in established laboratory processes with published performance envelopes [<xref ref-type="bibr" rid="B2">2</xref>].</p>
        <table-wrap id="tbl23">
          <label>Table 23</label>
          <table>
            <tbody>
              <tr>
                <td>
                  <bold>Layer</bold>
                </td>
                <td>
                  <bold>Material</bold>
                </td>
                <td>
                  <bold>Process</bold>
                </td>
                <td>
                  <bold>Basis</bold>
                </td>
              </tr>
              <tr>
                <td>P1 mesh</td>
                <td>SiN or SOI</td>
                <td>AIM Photonics PDK 5.5</td>
                <td>commercial</td>
              </tr>
              <tr>
                <td>P1 laser source</td>
                <td>III-V InP</td>
                <td>imec heterogeneous</td>
                <td>commercial</td>
              </tr>
              <tr>
                <td>P2 OEO</td>
                <td>SOI + III-V bonded</td>
                <td>imec + AIM</td>
                <td>commercial</td>
              </tr>
              <tr>
                <td>P3 SOA loop</td>
                <td>In Ga As P</td>
                <td>III-V bonded</td>
                <td>commercial</td>
              </tr>
              <tr>
                <td>P4 phononic crystal</td>
                <td>diamond, 20 nm features</td>
                <td>e-beam lithography</td>
                <td>laboratory</td>
              </tr>
              <tr>
                <td>P5 memristor</td>
                <td>HfO2</td>
                <td>back-end integration</td>
                <td>cited</td>
              </tr>
              <tr>
                <td>P6-A Casimir cavity</td>
                <td>silicon MEMS</td>
                <td>custom fab</td>
                <td>laboratory</td>
              </tr>
              <tr>
                <td>P6-B DCE circuit</td>
                <td>superconducting Al or Nb</td>
                <td>custom cryogenic</td>
                <td>laboratory</td>
              </tr>
              <tr>
                <td>P6-C sonoluminescence</td>
                <td>quartz cell + piezo</td>
                <td>benchtop assembly</td>
                <td>laboratory</td>
              </tr>
              <tr>
                <td>CS.* companion die</td>
                <td>TSMC N3E</td>
                <td>Paper XVII</td>
                <td>commercial</td>
              </tr>
            </tbody>
          </table>
        </table-wrap>
      </sec>
      <sec id="sec16dot2">
        <title>16.2. Foundry Options</title>
        <p>Primary foundries: AIM Photonics (P1 mesh, packaging), imec (III-V bonding), Lioni X (SiN low-loss), IHP (BiCMOS driver ICs), Fraunhofer HHI (packaging), TSMC N3E (CS.* die). Secondary sources documented per Section 17.1.</p>
      </sec>
      <sec id="sec16dot3">
        <title>16.3. Fabrication Flow · Base P1 Variant</title>
        <p>Nine-step flow: SiN waveguide layer → mesh definition → phase-shifter loading → microring bank → III - V bonding → detector integration → electrical top metal → laser attach → optical packaging.</p>
      </sec>
    </sec>
    <sec id="sec17">
      <title>17. Supply Chain</title>
      <sec id="sec17dot1">
        <title>17.1. Critical-Path Components with Dual-Sourcing</title>
        <p>AIM Photonics SiN + LioniX SiN as parallel PDKs; imec III - V + Fraunhofer HHI III-V as parallel bonding paths; TSMC N3E + Samsung SF3 as parallel N3-class options for the CS.* companion die. Diamondphononic-crystal fabrication triple-sourced across three e-beam-capable laboratories.</p>
      </sec>
      <sec id="sec17dot2">
        <title>17.2. IP Licensing Per-Unit Cost</title>
        <p>SiFive P670 or Andes AX65 RV64GC core IP: USD 3 - 6/unit at scale. AIM Photonics PDK royalty: USD 12 - 25/unit. Tenstorrent Tensix (used as CS.* companion accelerator on select variants): open-sourceISA, no per-unit licence.</p>
      </sec>
      <sec id="sec17dot3">
        <title>17.3. First-Silicon Budget · CHAINSTATE-X SoC Full Variant</title>
        <table-wrap id="tbl24">
          <label>Table 24</label>
          <table>
            <tbody>
              <tr>
                <td>
                  <bold>Line item</bold>
                </td>
                <td>
                  <bold>USD</bold>
                </td>
                <td>
                  <bold>Notes</bold>
                </td>
              </tr>
              <tr>
                <td>Mask set (N3E, CS.* die)</td>
                <td>$34 M</td>
                <td>TSMC N3E</td>
              </tr>
              <tr>
                <td>MPW tape-out (P1 photonic)</td>
                <td>$0.9 M</td>
                <td>AIM Photonics</td>
              </tr>
              <tr>
                <td>MPW tape-out (P2/P3 III-V)</td>
                <td>$1.4 M</td>
                <td>imec</td>
              </tr>
              <tr>
                <td>Prototype packaging (CoWoS-L)</td>
                <td>$3.2 M</td>
                <td>TSMC OSAT</td>
              </tr>
              <tr>
                <td>Diamond phononic crystal lot</td>
                <td>$1.1 M</td>
                <td>custom lab run</td>
              </tr>
              <tr>
                <td>Casimir MEMS lot</td>
                <td>$0.6 M</td>
                <td>silicon MEMS</td>
              </tr>
              <tr>
                <td>Superconducting DCE circuit build</td>
                <td>$0.9 M</td>
                <td>cryogenic lab build</td>
              </tr>
              <tr>
                <td>Sonoluminescence cell prototypes</td>
                <td>$0.15 M</td>
                <td>benchtop</td>
              </tr>
              <tr>
                <td>Test &amp; characterisation (12 months)</td>
                <td>$4.8 M</td>
                <td>internal team</td>
              </tr>
              <tr>
                <td>Total first-silicon budget</td>
                <td>$47.05 M</td>
                <td>excludes NRE</td>
              </tr>
            </tbody>
          </table>
        </table-wrap>
      </sec>
    </sec>
    <sec id="sec18">
      <title>18. Benchmark Protocol and Performance Figures · Formal TTS · REVISED</title>
      <sec id="sec18dot1">
        <title>18.1. End-to-End Time-to-Solution · NEW Definition</title>
        <table-wrap id="tbl25">
          <label>Table 25</label>
          <table>
            <tbody>
              <tr>
                <td>
                  <bold>Formal TTS definition</bold>
                  v0.1 presented a Max Cut figure of 150 ns and a ~4000× perf-per-watt ratio against D-Wave in the same table. The 150 ns is the OEO physical evolution/settling time; competitors are typically benchmarked on end-to-end time-to-solution, which includes loading, programming, readout, verification, and restarts. Comparing a physical evolution time against end-to-end solve times is not a like-for-like comparison. v0.2defines TTS formally and separates the two rows in every relevant table.
                  <bold>Definition of one trial.</bold>
                  <inline-formula>
                    <mml:math>
                      <mml:mrow>
                        <mml:msub>
                          <mml:mi>T</mml:mi>
                          <mml:mrow>
                            <mml:mtext>trial</mml:mtext>
                          </mml:mrow>
                        </mml:msub>
                        <mml:mo>=</mml:mo>
                        <mml:msub>
                          <mml:mi>T</mml:mi>
                          <mml:mrow>
                            <mml:mtext>load</mml:mtext>
                          </mml:mrow>
                        </mml:msub>
                        <mml:mo>+</mml:mo>
                        <mml:msub>
                          <mml:mi>T</mml:mi>
                          <mml:mrow>
                            <mml:mtext>program</mml:mtext>
                          </mml:mrow>
                        </mml:msub>
                        <mml:mo>+</mml:mo>
                        <mml:msub>
                          <mml:mi>T</mml:mi>
                          <mml:mrow>
                            <mml:mtext>evolve</mml:mtext>
                          </mml:mrow>
                        </mml:msub>
                        <mml:mo>+</mml:mo>
                        <mml:msub>
                          <mml:mi>T</mml:mi>
                          <mml:mrow>
                            <mml:mtext>read</mml:mtext>
                          </mml:mrow>
                        </mml:msub>
                        <mml:mo>+</mml:mo>
                        <mml:msub>
                          <mml:mi>T</mml:mi>
                          <mml:mrow>
                            <mml:mtext>verify</mml:mtext>
                          </mml:mrow>
                        </mml:msub>
                        <mml:mo>+</mml:mo>
                        <mml:msub>
                          <mml:mi>T</mml:mi>
                          <mml:mrow>
                            <mml:mtext>restart</mml:mtext>
                          </mml:mrow>
                        </mml:msub>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                  <bold>Definition of TTS.</bold>
                  If
                  <inline-formula>
                    <mml:math>
                      <mml:mrow>
                        <mml:msub>
                          <mml:mi>p</mml:mi>
                          <mml:mi>s</mml:mi>
                        </mml:msub>
                        <mml:mrow>
                          <mml:mo>(</mml:mo>
                          <mml:mi>q</mml:mi>
                          <mml:mo>)</mml:mo>
                        </mml:mrow>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                  is the probability that one independent trial returns a solution satisfying quality threshold
                  <italic>q</italic>
                  , then the time to obtain success probability
                  <inline-formula>
                    <mml:math>
                      <mml:mrow>
                        <mml:msup>
                          <mml:mi>p</mml:mi>
                          <mml:mo>*</mml:mo>
                        </mml:msup>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                  is
                  <inline-formula>
                    <mml:math>
                      <mml:mrow>
                        <mml:mtext>TTS</mml:mtext>
                        <mml:mrow>
                          <mml:mo>(</mml:mo>
                          <mml:mrow>
                            <mml:msup>
                              <mml:mi>p</mml:mi>
                              <mml:mo>*</mml:mo>
                            </mml:msup>
                            <mml:mo>,</mml:mo>
                            <mml:mi>q</mml:mi>
                          </mml:mrow>
                          <mml:mo>)</mml:mo>
                        </mml:mrow>
                        <mml:mo>=</mml:mo>
                        <mml:msub>
                          <mml:mi>T</mml:mi>
                          <mml:mrow>
                            <mml:mtext>trial</mml:mtext>
                          </mml:mrow>
                        </mml:msub>
                        <mml:mo>⋅</mml:mo>
                        <mml:mrow>
                          <mml:mo>[</mml:mo>
                          <mml:mrow>
                            <mml:mrow>
                              <mml:mrow>
                                <mml:mi>ln</mml:mi>
                                <mml:mrow>
                                  <mml:mo>(</mml:mo>
                                  <mml:mrow>
                                    <mml:mn>1</mml:mn>
                                    <mml:mo>−</mml:mo>
                                    <mml:msup>
                                      <mml:mi>p</mml:mi>
                                      <mml:mo>*</mml:mo>
                                    </mml:msup>
                                  </mml:mrow>
                                  <mml:mo>)</mml:mo>
                                </mml:mrow>
                              </mml:mrow>
                              <mml:mo>/</mml:mo>
                              <mml:mrow>
                                <mml:mi>ln</mml:mi>
                                <mml:mrow>
                                  <mml:mo>(</mml:mo>
                                  <mml:mrow>
                                    <mml:mn>1</mml:mn>
                                    <mml:mo>−</mml:mo>
                                    <mml:msub>
                                      <mml:mi>p</mml:mi>
                                      <mml:mi>s</mml:mi>
                                    </mml:msub>
                                    <mml:mrow>
                                      <mml:mo>(</mml:mo>
                                      <mml:mi>q</mml:mi>
                                      <mml:mo>)</mml:mo>
                                    </mml:mrow>
                                  </mml:mrow>
                                  <mml:mo>)</mml:mo>
                                </mml:mrow>
                              </mml:mrow>
                            </mml:mrow>
                          </mml:mrow>
                          <mml:mo>]</mml:mo>
                        </mml:mrow>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                  .
                  <bold>Quality threshold.</bold>
                  For MaxCut:
                  <inline-formula>
                    <mml:math display="inline">
                      <mml:mrow>
                        <mml:mi>q</mml:mi>
                        <mml:mo>=</mml:mo>
                        <mml:mrow>
                          <mml:mrow>
                            <mml:mi>C</mml:mi>
                            <mml:mrow>
                              <mml:mo>(</mml:mo>
                              <mml:mover accent="true">
                                <mml:mi>s</mml:mi>
                                <mml:mo>^</mml:mo>
                              </mml:mover>
                              <mml:mo>)</mml:mo>
                            </mml:mrow>
                          </mml:mrow>
                          <mml:mo>/</mml:mo>
                          <mml:mrow>
                            <mml:msup>
                              <mml:mi>C</mml:mi>
                              <mml:mo>*</mml:mo>
                            </mml:msup>
                          </mml:mrow>
                        </mml:mrow>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                  , with
                  <italic>q</italic>
                  ≥ 0.99 corresponding to the paper’s existing “within1% of the reference ground state” wording. Same
                  <italic>q</italic>
                  used in the Section 22.4 falsification threshold.
                </td>
              </tr>
              <tr>
                <td>
                  <bold>Renamed rows in the benchmark table.</bold>
                  The 150 ns entry is renamed
                  <bold>Physical evolution time</bold>
                  . A new row
                  <bold>End-to-end TTS @ 99% success, ≥99% quality</bold>
                  is added; its value is currently marked TBD until the load/program/readout/verification times and single-trial success probability are experimentally established.
                  <bold>Withdrawn claim.</bold>
                  The v0.1 Section 18.2
                  <italic>~</italic>
                  4000×
                  <italic>vs D-Wave</italic>
                  perf-per-watt ratio is withdrawn from v0.2 because it was derived from the physical evolution time rather than end-to-end TTS. Replacement text:
                  <italic>not yet established; physical-evolution target =</italic>
                  150
                  <italic>ns; end-to-end TTS TBD.</italic>
                </td>
              </tr>
            </tbody>
          </table>
        </table-wrap>
      </sec>
      <sec id="sec18dot2">
        <title>18.2. Benchmark Table · E/A/T Status Column Added</title>
        <p>Rows previously merging demonstrated components with target metrics are now separated. Numerical values from cited external experiments are labelled A; CHAINSTATE-X targets are labelled T; nothing on CHAINSTATE-X hardware has yet been experimentally demonstrated (no E rows).</p>
        <table-wrap id="tbl26">
          <label>Table 26</label>
          <table>
            <tbody>
              <tr>
                <td>
                  <bold>Device</bold>
                </td>
                <td>
                  <bold>Class</bold>
                </td>
                <td>
                  <bold>MaxCut 256</bold>
                  <bold>T</bold>
                  <bold>evolve</bold>
                </td>
                <td>
                  <bold>MaxCut 256</bold>
                  <bold>end-</bold>
                  <bold>to-end TTS</bold>
                </td>
                <td>
                  <bold>Power/card</bold>
                </td>
                <td>
                  <bold>Constitutional</bold>
                </td>
                <td>
                  <bold>Status</bold>
                </td>
              </tr>
              <tr>
                <td>Nvidia B200</td>
                <td>General GPU</td>
                <td>100 μs (MCMC)</td>
                <td>100 μs+</td>
                <td>1000 W</td>
                <td>none</td>
                <td>
                  <bold>A</bold>
                </td>
              </tr>
              <tr>
                <td>AMD MI450</td>
                <td>General GPU</td>
                <td>90 μs</td>
                <td>90 μs+</td>
                <td>1000 W</td>
                <td>none</td>
                <td>
                  <bold>A</bold>
                </td>
              </tr>
              <tr>
                <td>Google TPU v5p</td>
                <td>Purpose GPU</td>
                <td>300 μs</td>
                <td>300 μs+</td>
                <td>280 W</td>
                <td>none</td>
                <td>
                  <bold>A</bold>
                </td>
              </tr>
              <tr>
                <td>Groq LPU</td>
                <td>Data flow SRAM</td>
                <td>100 μs</td>
                <td>100 μs+</td>
                <td>400 W</td>
                <td>none</td>
                <td>
                  <bold>A</bold>
                </td>
              </tr>
              <tr>
                <td>Cerebras WSE-3</td>
                <td>Wafer-scale</td>
                <td>50 μs</td>
                <td>50 μs+</td>
                <td>15 kW</td>
                <td>none</td>
                <td>
                  <bold>A</bold>
                </td>
              </tr>
              <tr>
                <td>D-Wave Advantage 2</td>
                <td>Quantum annealer</td>
                <td>10 μs (7 k qubits)</td>
                <td>end-to-end TBD</td>
                <td>25 kW</td>
                <td>none</td>
                <td>
                  <bold>A</bold>
                </td>
              </tr>
              <tr>
                <td>Fujitsu Digital Annealer 4</td>
                <td>Digital annealer</td>
                <td>50 μs</td>
                <td>50 μs+</td>
                <td>700 W</td>
                <td>none</td>
                <td>
                  <bold>A</bold>
                </td>
              </tr>
              <tr>
                <td>Toshiba SBM</td>
                <td>Sim. bifurcation</td>
                <td>40 μs</td>
                <td>40 μs+</td>
                <td>400 W</td>
                <td>none</td>
                <td>
                  <bold>A</bold>
                </td>
              </tr>
              <tr>
                <td>CHAINSTATE-P2</td>
                <td>Constitutional</td>
                <td>150 ns (physical evolution)</td>
                <td>TBD experimentally</td>
                <td>300 W</td>
                <td>hw</td>
                <td>
                  <bold>T</bold>
                </td>
              </tr>
              <tr>
                <td>CHAINSTATE-XSoC</td>
                <td>Full transmedium</td>
                <td>150 ns (physical evolution)</td>
                <td>TBD experimentally</td>
                <td>380 W</td>
                <td>hw</td>
                <td>
                  <bold>T</bold>
                </td>
              </tr>
            </tbody>
          </table>
        </table-wrap>
        <p><inline-formula><mml:math><mml:mrow><mml:msub><mml:mi> T </mml:mi><mml:mrow><mml:mtext> evolve </mml:mtext></mml:mrow></mml:msub></mml:mrow></mml:math></inline-formula> for CHAINSTATE-P2/CHAINSTATE-X SoC is the photonic OEO settling time [<xref ref-type="bibr" rid="B9">9</xref>][<xref ref-type="bibr" rid="B12">12</xref>]. End-to-end TTS additionally counts <inline-formula><mml:math><mml:mrow><mml:msub><mml:mi> T </mml:mi><mml:mrow><mml:mtext> load </mml:mtext></mml:mrow></mml:msub></mml:mrow></mml:math></inline-formula> , <inline-formula><mml:math><mml:mrow><mml:msub><mml:mi> T </mml:mi><mml:mrow><mml:mtext> program </mml:mtext></mml:mrow></mml:msub></mml:mrow></mml:math></inline-formula> , <inline-formula><mml:math><mml:mrow><mml:msub><mml:mi> T </mml:mi><mml:mrow><mml:mtext> read </mml:mtext></mml:mrow></mml:msub></mml:mrow></mml:math></inline-formula> , <inline-formula><mml:math><mml:mrow><mml:msub><mml:mi> T </mml:mi><mml:mrow><mml:mtext> verify </mml:mtext></mml:mrow></mml:msub></mml:mrow></mml:math></inline-formula> , <inline-formula><mml:math><mml:mrow><mml:msub><mml:mi> T </mml:mi><mml:mrow><mml:mtext> restart </mml:mtext></mml:mrow></mml:msub></mml:mrow></mml:math></inline-formula> , and single-trial success probability against the <italic>q</italic> = 0.99 quality threshold; these are TBD experimentally.</p>
      </sec>
      <sec id="sec18dot3">
        <title>18.3. Perf-per-Watt · ~4000× Claim Withdrawn</title>
        <table-wrap id="tbl27">
          <label>Table 27</label>
          <table>
            <tbody>
              <tr>
                <td>
                  <bold>Perf-per-watt table restated</bold>
                  <bold>.</bold>
                  <bold>The v0.1 Section 18.2 perf-per-watt table gave a ~4000</bold>
                  <bold>×</bold>
                  <bold>ratio for MaxCut 256 against D-Wave, using the physical-evolution time as CHAINSTATE-X</bold>
                  <bold>’</bold>
                  <bold>s figure of merit. v0.2 withdraws this ratio.</bold>
                </td>
              </tr>
            </tbody>
          </table>
        </table-wrap>
        <table-wrap id="tbl28">
          <label>Table 28</label>
          <table>
            <tbody>
              <tr>
                <td>
                  <bold>Workload</bold>
                </td>
                <td>
                  <bold>Best merchant device</bold>
                </td>
                <td>
                  <bold>CHAINSTATE-X SoC status</bold>
                </td>
                <td>
                  <bold>Status</bold>
                </td>
              </tr>
              <tr>
                <td>MaxCut 256 (end-to-end TTS)</td>
                <td>D-Wave Advantage2</td>
                <td>not yet established · physical- evolution target = 150 ns</td>
                <td>
                  <bold>T</bold>
                </td>
              </tr>
              <tr>
                <td>Twin-step BF16</td>
                <td>Cerebras WSE-3</td>
                <td>
                  target ≥ 2.6 × 10
                  <sup>6</sup>
                  steps/s/W
                </td>
                <td>
                  <bold>T</bold>
                </td>
              </tr>
              <tr>
                <td>128 × 128 dense matmul(photonic)</td>
                <td>
                  Lightelligence PACE2 [
                  <xref ref-type="bibr" rid="B3">3</xref>
                  ]
                </td>
                <td>comparable target (≈109 ops/s/W)</td>
                <td>
                  <bold>T</bold>
                </td>
              </tr>
              <tr>
                <td>Constitutional receipt-signedops</td>
                <td>—</td>
                <td>only device with all ops signed</td>
                <td>
                  <bold>T</bold>
                </td>
              </tr>
            </tbody>
          </table>
        </table-wrap>
      </sec>
    </sec>
    <sec id="sec19">
      <title>19. Game Theory of the Market and Classified Programmes</title>
      <sec id="sec19dot1">
        <title>19.1. The Four Games</title>
        <p>G1 commercial photonic accelerator market · G2 combinatorial-optimisation market · G3sovereign-compute market · G4 classified programmes. CHAINSTATE-X strategically enters G1 first with P1, expands into G2 with P2, and offers G3/G4 buyers the P3 research host with selectable P6-A/B/C configuration.</p>
      </sec>
      <sec id="sec19dot2">
        <title>19.2. The Classified-Programme Landscape (G4)</title>
        <p>DARPA HIVE/DPRIVE/MOSAICS, UK ARIA, Euro HPC JU, and equivalent sovereign programmes are prospective buyers of the P3 research variant. The constitutional layer is the primary technical differentiator against merchant photonic accelerators.</p>
      </sec>
      <sec id="sec19dot3">
        <title>19.3. Strategic Dimensions and Dominance Analysis</title>
        <p>Six strategic dimensions: manufacturability, constitutional discipline, compute-density-per-watt, tolerance to non-Deontic customers, supply-chain-diversification, and ISA sovereignty. CHAINSTATE-X occupies dominance regions on constitutional discipline, ISA sovereignty, and supply-chain diversification; competes on manufacturability and compute-density-per-watt; and does not compete on tolerance to non-Deontic customers by design.</p>
      </sec>
      <sec id="sec19dot4">
        <title>19.4. What CHAINSTATE-X Wins</title>
        <p>Sovereign-compute contracts where hardware-enforced constitutional guarantees are required (Deontic V1 - V9 vetoes, SENTINEL 5-gate, ALLOW, Γ). CHAINSTATE-X is the only device family in this comparison with a hardware-enforced constitutional layer (Paper XVII Section 7).</p>
      </sec>
      <sec id="sec19dot5">
        <title>19.5. What CHAINSTATE-X Does Not Win</title>
        <p>Non-constitutional dense-inference workloads at scale, where B200/MI450/TPU v5p dominate on raw perf-per-watt. CHAINSTATE-X’s response in G1 is to concede these workloads and target CHAINSTATE-native workloads instead.</p>
      </sec>
      <sec id="sec19dot6">
        <title>19.6. The Classified-Programme Response Function</title>
        <p>Sovereign programmes value: (a) auditable provenance chain; (b) hardware-enforced constitutional discipline; (c) supply-chain independence from any single foreign foundry. CHAINSTATE-X delivers all three by design.</p>
      </sec>
    </sec>
    <sec id="sec20">
      <title>20. Phase Timeline</title>
      <sec id="sec20dot1">
        <title>Milestones</title>
        <table-wrap id="tbl29">
          <label>Table 29</label>
          <table>
            <tbody>
              <tr>
                <td>
                  <bold>Milestone</bold>
                </td>
                <td>
                  <bold>Date</bold>
                </td>
                <td>
                  <bold>Status</bold>
                </td>
              </tr>
              <tr>
                <td>Paper XIX v0.2 revision publication</td>
                <td>14 Sep 2026</td>
                <td>
                  <bold>T</bold>
                </td>
              </tr>
              <tr>
                <td>CS.PHYSOPT ISA specification frozen</td>
                <td>Q1 2027</td>
                <td>
                  <bold>T</bold>
                </td>
              </tr>
              <tr>
                <td>P1 MPW tape-out at AIM Photonics</td>
                <td>Q3 2027</td>
                <td>
                  <bold>T</bold>
                </td>
              </tr>
              <tr>
                <td>P1 first-silicon characterisation</td>
                <td>Q1 2028</td>
                <td>
                  <bold>T</bold>
                </td>
              </tr>
              <tr>
                <td>CHAINSTATE-P1 first commercial samples</td>
                <td>Q3 2028</td>
                <td>
                  <bold>T</bold>
                </td>
              </tr>
              <tr>
                <td>P2 MPW tape-out with III-V bonding</td>
                <td>Q4 2028</td>
                <td>
                  <bold>T</bold>
                </td>
              </tr>
              <tr>
                <td>CHAINSTATE-P2 first commercial samples</td>
                <td>Q1 2029</td>
                <td>
                  <bold>T</bold>
                </td>
              </tr>
              <tr>
                <td>P3 host qualification</td>
                <td>Q2 2029</td>
                <td>
                  <bold>T</bold>
                </td>
              </tr>
              <tr>
                <td>CHAINSTATE-P3 first research samples</td>
                <td>Q3 2029</td>
                <td>
                  <bold>T</bold>
                </td>
              </tr>
              <tr>
                <td>CHAINSTATE-X SoC full integration</td>
                <td>Q2 2030</td>
                <td>
                  <bold>T</bold>
                </td>
              </tr>
              <tr>
                <td>P6-A/B/C laboratory characterisation reports</td>
                <td>2028-2031</td>
                <td>
                  <bold>T</bold>
                </td>
              </tr>
            </tbody>
          </table>
        </table-wrap>
      </sec>
    </sec>
    <sec id="sec21">
      <title>21. Risk Register and Aggregate Exposure</title>
      <sec id="sec21dot1">
        <title>21.1. Technology Risks</title>
        <p>R1: MZI mesh loss exceeds 12 dB (P1). R2: OEO fidelity below 0.90 at 256 spins (P2). R3: reservoir Lyapunov exponent instability (P3). R4: diamond phononic crystal Q insufficient (P4). R5: memristor endurance below 108cycles (P5). R6: any P6-A/P6-B/P6-C laboratory result fails to reproduce the cited literature anchor. Each falsification threshold is spelled out in Section 22.4.</p>
      </sec>
      <sec id="sec21dot2">
        <title>21.2. Fabrication and Supply Risks</title>
        <p>Triple-source diamond phononic-crystal e-beam capacity; dual-source SiN PDK; dual-source III - V heterogeneous bonding; dual-source N3-class CS.* die manufacturing. Amkor SLIM and TSMCCo WoS-L as parallel advanced-packaging paths.</p>
      </sec>
      <sec id="sec21dot3">
        <title>21.3. Regulatory and Market Risks</title>
        <p>US export-control classification of the CS.PHYSOPT ISA and CHAINSTATE-X SoC. EU AI Act general-purpose model rules on downstream CHAINSTATE AGI applications. UK ARIA/Euro HPC procurement rules for the P3 research variant.</p>
      </sec>
      <sec id="sec21dot4">
        <title>21.4. Constitutional Risks</title>
        <p>Any post-silicon change to the Deontic policy ROM would require a public disclosure and a new anchor on Base 8453. The v0.2 policy ROM contents are public per Paper XVII Section 7.4.</p>
      </sec>
      <sec id="sec21dot5">
        <title>21.5. Aggregate Risk Exposure</title>
        <p>Aggregate technology-risk-adjusted first-silicon budget: 2.05 - 2.51 for merchant competitors (Section 19.3). CHAINSTATE-X’s constitutional-layer premium prices in against this exposure.</p>
      </sec>
    </sec>
    <sec id="sec22">
      <title>22. Formal Verification and Peer-Review Protocol</title>
      <sec id="sec22dot1">
        <title>22.1. Formal-Verification Methodology · Two-Gate SVA · REVISED</title>
        <table-wrap id="tbl30">
          <label>Table 30</label>
          <table>
            <tbody>
              <tr>
                <td>
                  <bold>Safety properties rewritten around EXEC_AUTH/RETIRE distinction</bold>
                  v0.1 Section 22.1 required every dispatched instruction to
                  <italic>reach the retirement checkpoint before any physical</italic>
                  <italic>execution begins</italic>
                  , which was incompatible with Section 14’s stage-4 → stage-6 → stage-7 ordering. v0.2 Section 14 defines two distinct gates (Section 14 REVISED) and Section 22.1 SVA properties are rewritten to match.Every Deontic-layer block is formally verified with Cadence Jasper Gold + Synopsys VC Formal. Each V1-V9veto is expressed as an SVA assertion pair (liveness + safety) per Paper XVII Section 7.4. The CS.PHYSOPT decoder adds ten SVA assertion pairs—one per CS.PHYSOPT family (Section 13.2)—verifying that:(a) every dispatched instruction passes the
                  <bold>pre-execution authorization checkpoi</bold>
                  <bold>nt (Gate A ·</bold>
                  <bold>EXEC_AUTH)</bold>
                  before physical execution begins on the target substrate;(b) no physical substrate can complete without producing a signed receipt at the
                  <bold>post-execution retirement checkpoint (Gate B · RETIRE)</bold>
                  ; and(c) no P6-A/P6-B/P6-C tagged result can influence any decision-tagged operation downstream (equation25). Machine-checked artefacts are archived to the same Base 8453 anchor chain the substrate uses in operation, so the verification is auditable end-to-end.
                </td>
              </tr>
            </tbody>
          </table>
        </table-wrap>
        <p>SVA Properties · v0.2 Canonical Form</p>
        <p>The three canonical SVA safety properties written against the two-gate model.</p>
        <p>Safety 1 EXECUTE ⇒ EXEC_AUTH</p>
        <p>No substrate may execute an instruction that has not received an EXEC_AUTH decision from the verified Deontic path at Gate A.</p>
        <p>Safety 2 RETIRE ⇒ VERIFY</p>
        <p>No instruction may reach the architectural RETIRE checkpoint at Gate B without completing measurement and verification.</p>
        <p>Safety 3 DECISION_USE(P6_RESULT) ⇒ FALSE</p>
        <p>No decision-tagged operation may consume a P6-A, P6-B, or P6-C tagged result unless the result has passed the appropriate non-research path (<italic>i.e.</italic> has been re-classified out of the RESEARCH epistemic class via the ALLOW gate). This preserves the epistemic-class check of Paper XVII Section 7 and Section 10.4 of this paper.</p>
      </sec>
      <sec id="sec22dot2">
        <title>22.2. Physical-Substrate Self-Test</title>
        <p>Each substrate P1 - P5 has a dedicated boot-time self-test. P1 mesh calibration measures every MZI’s insertion loss and phase-shifter range and fails safe if any cell exceeds fabricated tolerance. P2 Ising engine self-test runs a known 32-spin MaxCut and checks against the known ground state. P3 reservoir self-test measures <italic>λ</italic>1 on a known input signal and fails safe if outside the Section 7.4 trust region. P4 phononic self-test measures bandgap edges via a swept optical probe. P5 memristor self-testwrites and reads a checkerboard pattern to every crossbar row. P6-A (if attached) self-tests the Casimir gap through capacitive readout and refuses to enable if calibration fails. P6-B and P6-C follow analogous laboratory-configuration self-tests.</p>
      </sec>
      <sec id="sec22dot3">
        <title>22.3. Peer-Review Protocol</title>
        <p>This v0.2 paper is intended for peer review as follows: (a) archival version submitted to ResearchGate under Paper XIX numbering, v0.2; (b) supplementary artefacts (RTL, SVA properties, EL-IR compiler, benchmark suite) archived to a public Base 8453 anchor and mirrored on Git Hub <italic>Red Ciprian Pater/CHAINSTATE-X</italic>; (c) SVA formal-verification archive released as an OSS repository under Apache-2.0; (d) benchmark reproduction kit provided to independent reviewers on request. Reviewers are asked to independently reproduce three benchmarks: (i) a 128 × 128 photonic MZI mesh linear transformation, (ii) a 256-spin fully-connected MaxCut convergence, (iii) a P3 reservoir time-series prediction on the Mackey-Glass benchmark. Reproduction failure on any of these constitutes falsification of the corresponding section’s performance claims.</p>
      </sec>
      <sec id="sec22dot4">
        <title>22.4. Falsification Criteria per Section · Updated for v0.2</title>
        <table-wrap id="tbl31">
          <label>Table 31</label>
          <table>
            <tbody>
              <tr>
                <td>
                  <bold>Section</bold>
                </td>
                <td>
                  <bold>Substrate</bold>
                </td>
                <td>
                  <bold>Falsification threshold</bold>
                </td>
              </tr>
              <tr>
                <td>Section 5</td>
                <td>P1</td>
                <td>
                  MZI mesh insertion loss exceeds 12 dB end-to-end [
                  <xref ref-type="bibr" rid="B9">9</xref>
                  ]
                </td>
              </tr>
              <tr>
                <td>Section 6</td>
                <td>P2</td>
                <td>Ising coupling-matrix fidelity falls below 0.90 (relaxed from 0.986 target)</td>
              </tr>
              <tr>
                <td>Section 7</td>
                <td>P3</td>
                <td>
                  Reservoir stability trust region fails on Mackey-Glass benchmark (NRMSE ≥ 0.1) or
                  <inline-formula>
                    <mml:math display="inline">
                      <mml:mrow>
                        <mml:msub>
                          <mml:mover accent="true">
                            <mml:mi>λ</mml:mi>
                            <mml:mo>^</mml:mo>
                          </mml:mover>
                          <mml:mn>1</mml:mn>
                        </mml:msub>
                        <mml:mo>−</mml:mo>
                        <mml:msub>
                          <mml:mi>u</mml:mi>
                          <mml:mi>λ</mml:mi>
                        </mml:msub>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                  exceeds
                  <inline-formula>
                    <mml:math display="inline">
                      <mml:mrow>
                        <mml:msub>
                          <mml:mi>λ</mml:mi>
                          <mml:mrow>
                            <mml:mtext>fuse</mml:mtext>
                          </mml:mrow>
                        </mml:msub>
                        <mml:mo>−</mml:mo>
                        <mml:msub>
                          <mml:mi>δ</mml:mi>
                          <mml:mi>λ</mml:mi>
                        </mml:msub>
                      </mml:mrow>
                    </mml:math>
                  </inline-formula>
                </td>
              </tr>
              <tr>
                <td>Section 8</td>
                <td>P4</td>
                <td>Diamond phononic crystal bandgap fails to demonstrate 50 - 70 GHz</td>
              </tr>
              <tr>
                <td>Section 9</td>
                <td>P5</td>
                <td>HfO2crossbar shows fewer than 104distinct analog states</td>
              </tr>
              <tr>
                <td>Section 10.1</td>
                <td>P6-A</td>
                <td>
                  Casimir cavity Q or force-sensitivity fails to reproduce cited [
                  <xref ref-type="bibr" rid="B16">16</xref>
                  ] envelope
                </td>
              </tr>
              <tr>
                <td>Section 10.2</td>
                <td>P6-B</td>
                <td>
                  DCE photon statistics fail to reproduce [
                  <xref ref-type="bibr" rid="B19">19</xref>
                  ] Bogoliubov signature
                </td>
              </tr>
              <tr>
                <td>Section 10.3</td>
                <td>P6-C</td>
                <td>Sonoluminescence spectrum fails to correlate with any CS.* classification (per programme criterion)</td>
              </tr>
              <tr>
                <td>Section 18.1</td>
                <td>TTS</td>
                <td>End-to-end TTS at q = 0.99, p* = 0.99 exceeds 100 μs on the 256-spin reference graph (matching best merchant competitor)</td>
              </tr>
            </tbody>
          </table>
        </table-wrap>
      </sec>
    </sec>
    <sec id="sec23">
      <title>Appendix: CHAINSTATE-X Architecture Summary</title>
      <p>The complete architecture spans seven physical layers L0 - L6 with a common CS.PHYSOPT ISA, an RV64GCexecutive, six parallel physical substrates P1 - P6, and a measurement + provenance chain that anchors every retired instruction to Base 8453.</p>
      <table-wrap id="tbl32">
        <label>Table 32</label>
        <table>
          <tbody>
            <tr>
              <td>
                <bold>Symbol</bold>
              </td>
              <td>
                <bold>Meaning</bold>
              </td>
              <td>
                <bold>Symbol</bold>
              </td>
              <td>
                <bold>Meaning</bold>
              </td>
            </tr>
            <tr>
              <td>
                <italic>λ</italic>
              </td>
              <td>wavelength</td>
              <td>
                <italic>T</italic>
              </td>
              <td>temperature</td>
            </tr>
            <tr>
              <td>
                <italic>φ</italic>
              </td>
              <td>optical phase</td>
              <td>
                <italic>B</italic>
              </td>
              <td>magnetic field</td>
            </tr>
            <tr>
              <td>
                <italic>p</italic>
              </td>
              <td>polarisation</td>
              <td>
                <italic>E</italic>
              </td>
              <td>electric field</td>
            </tr>
            <tr>
              <td>
                <italic>m</italic>
              </td>
              <td>spatial mode</td>
              <td>
                <italic>μ</italic>
              </td>
              <td>chemical potential</td>
            </tr>
            <tr>
              <td>
                <italic>t</italic>
              </td>
              <td>temporal mode</td>
              <td>
                <italic>ε</italic>
              </td>
              <td>strain</td>
            </tr>
            <tr>
              <td>
                <italic>d</italic>
              </td>
              <td>cavity gap</td>
              <td>
                <italic>J</italic>
              </td>
              <td>coupling</td>
            </tr>
            <tr>
              <td>
                <italic>κ</italic>
              </td>
              <td>loss rate</td>
              <td>
                <italic>Ω</italic>
              </td>
              <td>drive frequency</td>
            </tr>
          </tbody>
        </table>
      </table-wrap>
      <p><italic>Canonical state vector</italic><italic>Λ</italic> = (<italic>λ</italic>, <italic>φ</italic>, <italic>p</italic>, <italic>m</italic>, <italic>t</italic>, <italic>T</italic>, <italic>B</italic>, <italic>E</italic>, <italic>μ</italic>, <italic>ε</italic>, <italic>d</italic>, <italic>J</italic>, <italic>κ</italic>, <italic>Ω</italic>) ·<bold>14 scalar variables</bold>. Geometry is a derived configuration object rather than one of the fourteen scalar state variables. This corrects the earlier v0.1 Section 3.2, which enumerated 12 elements while claiming the same 14-variable list.</p>
    </sec>
    <sec id="sec24">
      <title>NOTES</title>
      <p>*A Programmable Heterogeneous Physical Substrate That Maps CHAINSTATE Energy Landscapes onto Optical, Optoelectronic, Phononic, Thermodynamic and—Experimentally—QED Boundary Degrees of Freedom, with a RISC-V Executive, a Common CS.PHYSOPT Instruction Set, and Hardware-Enforced Constitutional Guarantees Inherited from Paper XVII.</p>
    </sec>
  </body>
  <back>
    <ref-list>
      <title>References</title>
      <ref id="B1">
        <label>1.</label>
        <citation-alternatives>
          <mixed-citation publication-type="web">American Institute for Manufacturing Integrated Photonics (AIM Photonics). Process Design Kit (PDK) Documentation. Foundry Documentation, Current Release. https://www.aimphotonics.com/pdk</mixed-citation>
          <element-citation publication-type="web">
            <person-group person-group-type="author">
              <string-name>Documentation, C</string-name>
            </person-group>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B2">
        <label>2.</label>
        <citation-alternatives>
          <mixed-citation publication-type="journal">Fahrenkopf, N.M., McDonough, C., Leake, G.L., Su, Z., Timurdogan, E. and Coolbaugh, D.D. (2019) The AIM Photonics MPW: A Highly Accessible Cutting Edge Technology for Rapid Prototyping of Photonic Integrated Circuits. <italic>IEEE Journal of Selected Topics in Quantum Electronics</italic>, 25, 1-6. https://doi.org/10.1109/jstqe.2019.2935698 <pub-id pub-id-type="doi">10.1109/jstqe.2019.2935698</pub-id><ext-link ext-link-type="uri" xlink:href="https://doi.org/10.1109/jstqe.2019.2935698">https://doi.org/10.1109/jstqe.2019.2935698</ext-link></mixed-citation>
          <element-citation publication-type="journal">
            <person-group person-group-type="author">
              <string-name>Fahrenkopf, N.M.</string-name>
              <string-name>McDonough, C.</string-name>
              <string-name>Leake, G.L.</string-name>
              <string-name>Su, Z.</string-name>
              <string-name>Timurdogan, E.</string-name>
              <string-name>Coolbaugh, D.D.</string-name>
            </person-group>
            <year>2019</year>
            <article-title>The AIM Photonics MPW: A Highly Accessible Cutting Edge Technology for Rapid Prototyping of Photonic Integrated Circuits</article-title>
            <source>IEEE Journal of Selected Topics in Quantum Electronics</source>
            <volume>25</volume>
            <pub-id pub-id-type="doi">10.1109/jstqe.2019.2935698</pub-id>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B3">
        <label>3.</label>
        <citation-alternatives>
          <mixed-citation publication-type="other">Shen, Y., Harris, N.C., Skirlo, S., Prabhu, M., Baehr-Jones, T., Hochberg, M., <italic>et al</italic>. (2017) Deep Learning with Coherent Nanophotonic Circuits. <italic>Nature Photonics</italic>, 11, 441-446. https://doi.org/10.1038/nphoton.2017.93 <pub-id pub-id-type="doi">10.1038/nphoton.2017.93</pub-id><ext-link ext-link-type="uri" xlink:href="https://doi.org/10.1038/nphoton.2017.93">https://doi.org/10.1038/nphoton.2017.93</ext-link></mixed-citation>
          <element-citation publication-type="other">
            <person-group person-group-type="author">
              <string-name>Shen, Y.</string-name>
              <string-name>Harris, N.C.</string-name>
              <string-name>Skirlo, S.</string-name>
              <string-name>Prabhu, M.</string-name>
              <string-name>Baehr-Jones, T.</string-name>
              <string-name>Hochberg, M.</string-name>
            </person-group>
            <year>2017</year>
            <article-title>Deep Learning with Coherent Nanophotonic Circuits</article-title>
            <source>Nature Photonics</source>
            <volume>11</volume>
            <pub-id pub-id-type="doi">10.1038/nphoton.2017.93</pub-id>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B4">
        <label>4.</label>
        <citation-alternatives>
          <mixed-citation publication-type="web">Lightmatter, Inc. Envise Product Page. Product Documentation. https://lightmatter.co/products/envise/</mixed-citation>
          <element-citation publication-type="web">
            <person-group person-group-type="author">
              <string-name>Lightmatter, I</string-name>
            </person-group>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B5">
        <label>5.</label>
        <citation-alternatives>
          <mixed-citation publication-type="web">Lightelligence, Inc. PACE Product Overview. Product Documentation. https://www.lightelligence.co/</mixed-citation>
          <element-citation publication-type="web">
            <person-group person-group-type="author">
              <string-name>Lightelligence, I</string-name>
            </person-group>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B6">
        <label>6.</label>
        <citation-alternatives>
          <mixed-citation publication-type="other">Pruessner, M.W., Rabinovich, W.S., Stievater, T.H., Kozak, D.A. and Sanghera, J.S. (2022) Broadband Silicon Nitride Integrated Polarization Rotators at 780 nm. <italic>Optics Express</italic>, 30, 45514-45528.</mixed-citation>
          <element-citation publication-type="other">
            <person-group person-group-type="author">
              <string-name>Pruessner, M.W.</string-name>
              <string-name>Rabinovich, W.S.</string-name>
              <string-name>Stievater, T.H.</string-name>
              <string-name>Kozak, D.A.</string-name>
              <string-name>Sanghera, J.S.</string-name>
            </person-group>
            <year>2022</year>
            <article-title>Broadband Silicon Nitride Integrated Polarization Rotators at 780 nm</article-title>
            <source>Optics Express</source>
            <volume>30</volume>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B7">
        <label>7.</label>
        <citation-alternatives>
          <mixed-citation publication-type="other">Dai, D. and Bowers, J.E. (2014) Silicon-Based On-Chip Multiplexing Technologies and Devices for Peta-bit Optical Interconnects. <italic>Nanophotonics</italic>, 3, 283-311. https://doi.org/10.1515/nanoph-2013-0021 <pub-id pub-id-type="doi">10.1515/nanoph-2013-0021</pub-id><ext-link ext-link-type="uri" xlink:href="https://doi.org/10.1515/nanoph-2013-0021">https://doi.org/10.1515/nanoph-2013-0021</ext-link></mixed-citation>
          <element-citation publication-type="other">
            <person-group person-group-type="author">
              <string-name>Dai, D.</string-name>
              <string-name>Bowers, J.E.</string-name>
            </person-group>
            <year>2014</year>
            <article-title>Silicon-Based On-Chip Multiplexing Technologies and Devices for Peta-bit Optical Interconnects</article-title>
            <source>Nanophotonics</source>
            <volume>3</volume>
            <pub-id pub-id-type="doi">10.1515/nanoph-2013-0021</pub-id>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B8">
        <label>8.</label>
        <citation-alternatives>
          <mixed-citation publication-type="other">Honjo, T., Sonobe, T., Inaba, K., Inagaki, T., Ikuta, T., Yamada, Y., <italic>et al</italic>. (2021) 100,000-Spin Coherent Ising Machine. <italic>Science Advances</italic>, 7, eabh0952. https://doi.org/10.1126/sciadv.abh0952 <pub-id pub-id-type="doi">10.1126/sciadv.abh0952</pub-id><pub-id pub-id-type="pmid">34586855</pub-id><ext-link ext-link-type="uri" xlink:href="https://doi.org/10.1126/sciadv.abh0952">https://doi.org/10.1126/sciadv.abh0952</ext-link></mixed-citation>
          <element-citation publication-type="other">
            <person-group person-group-type="author">
              <string-name>Honjo, T.</string-name>
              <string-name>Sonobe, T.</string-name>
              <string-name>Inaba, K.</string-name>
              <string-name>Inagaki, T.</string-name>
              <string-name>Ikuta, T.</string-name>
              <string-name>Yamada, Y.</string-name>
            </person-group>
            <year>2021</year>
            <article-title>100,000-Spin Coherent Ising Machine</article-title>
            <source>Science Advances</source>
            <volume>7</volume>
            <pub-id pub-id-type="doi">10.1126/sciadv.abh0952</pub-id>
            <pub-id pub-id-type="pmid">34586855</pub-id>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B9">
        <label>9.</label>
        <citation-alternatives>
          <mixed-citation publication-type="other">Inagaki, T., Haribara, Y., Igarashi, K., Sonobe, T., Tamate, S., Honjo, T., <italic>et al</italic>. (2016) A Coherent Ising Machine for 2000-Node Optimization Problems. <italic>Science</italic>, 354, 603-606. https://doi.org/10.1126/science.aah4243 <pub-id pub-id-type="doi">10.1126/science.aah4243</pub-id><pub-id pub-id-type="pmid">27811271</pub-id><ext-link ext-link-type="uri" xlink:href="https://doi.org/10.1126/science.aah4243">https://doi.org/10.1126/science.aah4243</ext-link></mixed-citation>
          <element-citation publication-type="other">
            <person-group person-group-type="author">
              <string-name>Inagaki, T.</string-name>
              <string-name>Haribara, Y.</string-name>
              <string-name>Igarashi, K.</string-name>
              <string-name>Sonobe, T.</string-name>
              <string-name>Tamate, S.</string-name>
              <string-name>Honjo, T.</string-name>
            </person-group>
            <year>2016</year>
            <article-title>A Coherent Ising Machine for 2000-Node Optimization Problems</article-title>
            <source>Science</source>
            <volume>354</volume>
            <pub-id pub-id-type="doi">10.1126/science.aah4243</pub-id>
            <pub-id pub-id-type="pmid">27811271</pub-id>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B10">
        <label>10.</label>
        <citation-alternatives>
          <mixed-citation publication-type="other">King, A.D., Raymond, J., Lanting, T., Harris, R., Zucca, A., Altomare, F., <italic>et al</italic>. (2023) Quantum Critical Dynamics in a 5,000-Qubit Programmable Spin Glass. <italic>Nature</italic>, 617, 61-66. https://doi.org/10.1038/s41586-023-05867-2 <pub-id pub-id-type="doi">10.1038/s41586-023-05867-2</pub-id><pub-id pub-id-type="pmid">37076625</pub-id><ext-link ext-link-type="uri" xlink:href="https://doi.org/10.1038/s41586-023-05867-2">https://doi.org/10.1038/s41586-023-05867-2</ext-link></mixed-citation>
          <element-citation publication-type="other">
            <person-group person-group-type="author">
              <string-name>King, A.D.</string-name>
              <string-name>Raymond, J.</string-name>
              <string-name>Lanting, T.</string-name>
              <string-name>Harris, R.</string-name>
              <string-name>Zucca, A.</string-name>
              <string-name>Altomare, F.</string-name>
            </person-group>
            <year>2023</year>
            <article-title>Quantum Critical Dynamics in a 5,000-Qubit Programmable Spin Glass</article-title>
            <source>Nature</source>
            <volume>617</volume>
            <pub-id pub-id-type="doi">10.1038/s41586-023-05867-2</pub-id>
            <pub-id pub-id-type="pmid">37076625</pub-id>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B11">
        <label>11.</label>
        <citation-alternatives>
          <mixed-citation publication-type="web">Boothby, K., Bunyk, P., Raymond, J. and Roy, A. (2020) Next-Generation Topology of D-Wave Quantum Processors. https://arxiv.org/abs/2003.00133</mixed-citation>
          <element-citation publication-type="web">
            <person-group person-group-type="author">
              <string-name>Boothby, K.</string-name>
              <string-name>Bunyk, P.</string-name>
              <string-name>Raymond, J.</string-name>
              <string-name>Roy, A.</string-name>
            </person-group>
            <year>2020</year>
            <article-title>Next-Generation Topology of D-Wave Quantum Processors</article-title>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B12">
        <label>12.</label>
        <citation-alternatives>
          <mixed-citation publication-type="other">Böhm, F., Verschaffelt, G. and Van der Sande, G. (2019) A Poor Man’s Coherent Ising Machine Based on Opto-Electronic Feedback Systems for Solving Optimization Problems. <italic>Nature Communications</italic>, 10, Article No. 3538. https://doi.org/10.1038/s41467-019-11484-3 <pub-id pub-id-type="doi">10.1038/s41467-019-11484-3</pub-id><pub-id pub-id-type="pmid">31395872</pub-id><ext-link ext-link-type="uri" xlink:href="https://doi.org/10.1038/s41467-019-11484-3">https://doi.org/10.1038/s41467-019-11484-3</ext-link></mixed-citation>
          <element-citation publication-type="other">
            <person-group person-group-type="author">
              <string-name>Verschaffelt, G.</string-name>
              <string-name>Sande, G.</string-name>
            </person-group>
            <year>2019</year>
            <article-title>A Poor Man’s Coherent Ising Machine Based on Opto-Electronic Feedback Systems for Solving Optimization Problems</article-title>
            <source>Nature Communications</source>
            <volume>10</volume>
            <elocation-id>No</elocation-id>
            <pub-id pub-id-type="doi">10.1038/s41467-019-11484-3</pub-id>
            <pub-id pub-id-type="pmid">31395872</pub-id>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B13">
        <label>13.</label>
        <citation-alternatives>
          <mixed-citation publication-type="other">Vandoorne, K., Mechet, P., Van Vaerenbergh, T., Fiers, M., Morthier, G., Verstraeten, D., <italic>et</italic><italic>al</italic>. (2014) Experimental Demonstration of Reservoir Computing on a Silicon Photonics Chip. <italic>Nature Communications</italic>, 5, Article No. 3541. https://doi.org/10.1038/ncomms4541 <pub-id pub-id-type="doi">10.1038/ncomms4541</pub-id><pub-id pub-id-type="pmid">24662967</pub-id><ext-link ext-link-type="uri" xlink:href="https://doi.org/10.1038/ncomms4541">https://doi.org/10.1038/ncomms4541</ext-link></mixed-citation>
          <element-citation publication-type="other">
            <person-group person-group-type="author">
              <string-name>Vandoorne, K.</string-name>
              <string-name>Mechet, P.</string-name>
              <string-name>Vaerenbergh, T.</string-name>
              <string-name>Fiers, M.</string-name>
              <string-name>Morthier, G.</string-name>
              <string-name>Verstraeten, D.</string-name>
            </person-group>
            <year>2014</year>
            <article-title>Experimental Demonstration of Reservoir Computing on a Silicon Photonics Chip</article-title>
            <source>Nature Communications</source>
            <volume>5</volume>
            <elocation-id>No</elocation-id>
            <pub-id pub-id-type="doi">10.1038/ncomms4541</pub-id>
            <pub-id pub-id-type="pmid">24662967</pub-id>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B14">
        <label>14.</label>
        <citation-alternatives>
          <mixed-citation publication-type="other">Bogaerts, W., De Heyn, P., Van Vaerenbergh, T., De Vos, K., Kumar Selvaraja, S., Claes, T., <italic>et al</italic>. (2012) Silicon Microring Resonators. <italic>Laser &amp; Photonics Reviews</italic>, 6, 47-73. https://doi.org/10.1002/lpor.201100017 <pub-id pub-id-type="doi">10.1002/lpor.201100017</pub-id><ext-link ext-link-type="uri" xlink:href="https://doi.org/10.1002/lpor.201100017">https://doi.org/10.1002/lpor.201100017</ext-link></mixed-citation>
          <element-citation publication-type="other">
            <person-group person-group-type="author">
              <string-name>Bogaerts, W.</string-name>
              <string-name>Heyn, P.</string-name>
              <string-name>Vaerenbergh, T.</string-name>
              <string-name>Vos, K.</string-name>
              <string-name>Selvaraja, S.</string-name>
              <string-name>Claes, T.</string-name>
            </person-group>
            <year>2012</year>
            <article-title>Silicon Microring Resonators</article-title>
            <source>Laser &amp; Photonics Reviews</source>
            <volume>6</volume>
            <pub-id pub-id-type="doi">10.1002/lpor.201100017</pub-id>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B15">
        <label>15.</label>
        <citation-alternatives>
          <mixed-citation publication-type="other">MacCabe, G.S., Ren, H., Luo, J., Cohen, J.D., Zhou, H., Sipahigil, A., <italic>et al</italic>. (2020) Nano-Acoustic Resonator with Ultralong Phonon Lifetime. <italic>Science</italic>, 370, 840-843. https://doi.org/10.1126/science.abc7312 <pub-id pub-id-type="doi">10.1126/science.abc7312</pub-id><pub-id pub-id-type="pmid">33184212</pub-id><ext-link ext-link-type="uri" xlink:href="https://doi.org/10.1126/science.abc7312">https://doi.org/10.1126/science.abc7312</ext-link></mixed-citation>
          <element-citation publication-type="other">
            <person-group person-group-type="author">
              <string-name>MacCabe, G.S.</string-name>
              <string-name>Ren, H.</string-name>
              <string-name>Luo, J.</string-name>
              <string-name>Cohen, J.D.</string-name>
              <string-name>Zhou, H.</string-name>
              <string-name>Sipahigil, A.</string-name>
            </person-group>
            <year>2020</year>
            <article-title>Nano-Acoustic Resonator with Ultralong Phonon Lifetime</article-title>
            <source>Science</source>
            <volume>370</volume>
            <pub-id pub-id-type="doi">10.1126/science.abc7312</pub-id>
            <pub-id pub-id-type="pmid">33184212</pub-id>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B16">
        <label>16.</label>
        <citation-alternatives>
          <mixed-citation publication-type="other">Klimchitskaya, G.L., Mohideen, U. and Mostepanenko, V.M. (2009) The Casimir Force between Real Materials: Experiment and Theory. <italic>Reviews of Modern Physics</italic>, 81, 1827-1885. https://doi.org/10.1103/revmodphys.81.1827 <pub-id pub-id-type="doi">10.1103/revmodphys.81.1827</pub-id><ext-link ext-link-type="uri" xlink:href="https://doi.org/10.1103/revmodphys.81.1827">https://doi.org/10.1103/revmodphys.81.1827</ext-link></mixed-citation>
          <element-citation publication-type="other">
            <person-group person-group-type="author">
              <string-name>Klimchitskaya, G.L.</string-name>
              <string-name>Mohideen, U.</string-name>
              <string-name>Mostepanenko, V.M.</string-name>
            </person-group>
            <year>2009</year>
            <article-title>The Casimir Force between Real Materials: Experiment and Theory</article-title>
            <source>Reviews of Modern Physics</source>
            <volume>81</volume>
            <pub-id pub-id-type="doi">10.1103/revmodphys.81.1827</pub-id>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B17">
        <label>17.</label>
        <citation-alternatives>
          <mixed-citation publication-type="other">Chan, H.B., Aksyuk, V.A., Kleiman, R.N., Bishop, D.J. and Capasso, F. (2001) Quantum Mechanical Actuation of Microelectromechanical Systems by the Casimir Force. <italic>Science</italic>, 291, 1941-1944. https://doi.org/10.1126/science.1057984 <pub-id pub-id-type="doi">10.1126/science.1057984</pub-id><pub-id pub-id-type="pmid">11239149</pub-id><ext-link ext-link-type="uri" xlink:href="https://doi.org/10.1126/science.1057984">https://doi.org/10.1126/science.1057984</ext-link></mixed-citation>
          <element-citation publication-type="other">
            <person-group person-group-type="author">
              <string-name>Chan, H.B.</string-name>
              <string-name>Aksyuk, V.A.</string-name>
              <string-name>Kleiman, R.N.</string-name>
              <string-name>Bishop, D.J.</string-name>
              <string-name>Capasso, F.</string-name>
            </person-group>
            <year>2001</year>
            <article-title>Quantum Mechanical Actuation of Microelectromechanical Systems by the Casimir Force</article-title>
            <source>Science</source>
            <volume>291</volume>
            <pub-id pub-id-type="doi">10.1126/science.1057984</pub-id>
            <pub-id pub-id-type="pmid">11239149</pub-id>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B18">
        <label>18.</label>
        <citation-alternatives>
          <mixed-citation publication-type="other">Lamoreaux, S.K. (1997) Demonstration of the Casimir Force in the 0.6 to 6 μm Range. <italic>Physical Review Letters</italic>, 78, 5-8. https://doi.org/10.1103/physrevlett.78.5 <pub-id pub-id-type="doi">10.1103/physrevlett.78.5</pub-id><ext-link ext-link-type="uri" xlink:href="https://doi.org/10.1103/physrevlett.78.5">https://doi.org/10.1103/physrevlett.78.5</ext-link></mixed-citation>
          <element-citation publication-type="other">
            <person-group person-group-type="author">
              <string-name>Lamoreaux, S.K.</string-name>
            </person-group>
            <year>1997</year>
            <article-title>Demonstration of the Casimir Force in the 0</article-title>
            <source>6 to 6 μm Range. Physical Review Letters</source>
            <volume>78</volume>
            <pub-id pub-id-type="doi">10.1103/physrevlett.78.5</pub-id>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B19">
        <label>19.</label>
        <citation-alternatives>
          <mixed-citation publication-type="other">Wilson, C.M., Johansson, G., Pourkabirian, A., Simoen, M., Johansson, J.R., Duty, T., <italic>et al</italic>. (2011) Observation of the Dynamical Casimir Effect in a Superconducting Circuit. <italic>Nature</italic>, 479, 376-379. https://doi.org/10.1038/nature10561 <pub-id pub-id-type="doi">10.1038/nature10561</pub-id><pub-id pub-id-type="pmid">22094697</pub-id><ext-link ext-link-type="uri" xlink:href="https://doi.org/10.1038/nature10561">https://doi.org/10.1038/nature10561</ext-link></mixed-citation>
          <element-citation publication-type="other">
            <person-group person-group-type="author">
              <string-name>Wilson, C.M.</string-name>
              <string-name>Johansson, G.</string-name>
              <string-name>Pourkabirian, A.</string-name>
              <string-name>Simoen, M.</string-name>
              <string-name>Johansson, J.R.</string-name>
              <string-name>Duty, T.</string-name>
            </person-group>
            <year>2011</year>
            <article-title>Observation of the Dynamical Casimir Effect in a Superconducting Circuit</article-title>
            <source>Nature</source>
            <volume>479</volume>
            <pub-id pub-id-type="doi">10.1038/nature10561</pub-id>
            <pub-id pub-id-type="pmid">22094697</pub-id>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B20">
        <label>20.</label>
        <citation-alternatives>
          <mixed-citation publication-type="other">Brenner, M.P., Hilgenfeldt, S. and Lohse, D. (2002) Single-Bubble Sonoluminescence. <italic>Reviews of Modern Physics</italic>, 74, 425-484. https://doi.org/10.1103/revmodphys.74.425 <pub-id pub-id-type="doi">10.1103/revmodphys.74.425</pub-id><ext-link ext-link-type="uri" xlink:href="https://doi.org/10.1103/revmodphys.74.425">https://doi.org/10.1103/revmodphys.74.425</ext-link></mixed-citation>
          <element-citation publication-type="other">
            <person-group person-group-type="author">
              <string-name>Brenner, M.P.</string-name>
              <string-name>Hilgenfeldt, S.</string-name>
              <string-name>Lohse, D.</string-name>
            </person-group>
            <year>2002</year>
            <article-title>Single-Bubble Sonoluminescence</article-title>
            <source>Reviews of Modern Physics</source>
            <volume>74</volume>
            <pub-id pub-id-type="doi">10.1103/revmodphys.74.425</pub-id>
          </element-citation>
        </citation-alternatives>
      </ref>
    </ref-list>
  </back>
</article>