TITLE:
Quantum Heat Engines; Multiple-State 1D Box System
AUTHORS:
Eny Latifah, Agus Purwanto
KEYWORDS:
Quantum Heat Engine; Quantum Thermodynamic Processes; Quantum First Law of Thermodynamic
JOURNAL NAME:
Journal of Modern Physics,
Vol.4 No.8,
August
13,
2013
ABSTRACT: We evaluate quantum Otto, Diesel and Brayton cycles employing
multiple-state 1D box system instead of ideal gas filled cylinder. The work and
heat are extracted using the change in the expectation of Hamiltonian of the
system which leads to the first law of thermodynamics to quantum system. The
first law makes available to redefine the force which is in fact not well
defined in a quantum mechanical system and then it is applied to define the
quantum version of thermodynamic processes, i.e.
isobaric, isovolume and adiabatic. As the results, the efficiency of quantum
Otto engine depends only on the compression ratio and will be higher than the
efficiency of quantum Diesel which can decrease by the widening of expansion
under isobaric process. The efficiency of quantum Brayton engine may reach
maximum on certain combination between the wide of box under isobaric expansion
and compression, under certain conditions. The amount of levels participated in
the quantum heat engine system will potentially reduce the performance of the
quantum heat cycles consisting isobaric process, but it can be resisted using
isobaric process controller.