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Updated: Mar 8, 2026

A Rapid Method for Modeling a Variable Cycle Engine
Published on: August 13, 2019
Speed and efficiency limits of multilevel incoherent heat engines
V Mukherjee1, W Niedenzu1, A G Kofman1,2
1Department of Chemical Physics, Weizmann Institute of Science, Rehovot 7610001, Israel.
Abstract:
We present a comprehensive theory of heat engines (HE) based on a quantum-mechanical "working fluid" (WF) with periodically modulated energy levels. The theory is valid for any periodicity of driving Hamiltonians that commute with themselves at all times and do not induce coherence in the WF. Continuous and stroke cycles arise in opposite limits of this theory, which encompasses hitherto unfamiliar cycle forms, dubbed here hybrid cycles. The theory allows us to discover the speed, power, and efficiency limits attainable by incoherently operating multilevel HE depending on the cycle form and the dynamical regimes.
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