TITLE:
Risk Measure Contextuality by Quantum Weak Value in Quantum Decision Theory
AUTHORS:
Miwaka Yamashita
KEYWORDS:
Quantum Decision Theory, Weak Value, Risk Measure, Time Evolution, Moral Hazard
JOURNAL NAME:
Journal of Mathematical Finance,
Vol.16 No.2,
April
30,
2026
ABSTRACT: This paper introduces decision-making and risk-measure models based on advanced quantum theory, which address the contextuality of decisions more flexibly than previous approaches. Contextuality affects how risk is perceived, and changes in decision-making are modeled using quantum time evolution and weak values. Numerical simulations reveal that the weak value model captures contextual shifts in risk magnitude in both directions—amplification and reduction—which cannot be expressed by simple projection or time evolution alone. Empirical applications include moral hazard and inverse moral hazard, where contextuality renders the risk either more or less severe, such as governmental monetary aids examples.