Quantum Brayton Engine of Non-Interacting Fermions in a One-Dimensional Box

TL;DR

This paper analyzes a quantum Brayton cycle using non-interacting fermions in a one-dimensional box, deriving efficiency and power characteristics, and exploring effects of finite cycle speed and length ratios.

Contribution

It provides analytical expressions for efficiency and power of the quantum Brayton cycle, highlighting the independence from particle number and the influence of length ratios.

Findings

Efficiency depends on length ratios, not particle number.

Power increases as the length ratio decreases.

Efficiency at maximum power improves with shorter length ratios.

Abstract

We consider the quantum Brayton cycle, constructed from non-interacting fermions, trapped in a one-dimensional box. The work and heat in this cycle are calculated from the expectation values of the Hamiltonian. We analytically calculated the efficiency of the cycle, efficiency at maximum work and Clausius relation as the function of the ratio of the lengths. We found that the efficiency of the cycle does not depend on the number of fermions. It depends on the ratios of the lengths of the cycle. While the power depends on the number of fermions. The irreversibility of the cycle also does not depend on the number of particles. It only depends on the ratio of the box lengths. Moreover, We also analysed the efficiency and the power of the cycle for the finite speed of the movement of the potential wall. We found that as we decrease the ratio of the lengths, the efficiency at maximum power and the maximum power of the cycle increases.