Quantum thermodynamic cycles in the forward and time-reversed regimes

TL;DR

This paper introduces a quantum engine model based on thermodynamic cycles with qubits, highlighting the existence of a quantum limit cycle that remains invariant under forward and reverse protocols, demonstrated using the Ising model.

Contribution

It reveals the existence of a quantum limit cycle in thermodynamic cycles, invariant under time reversal, providing a new quantum perspective on engine operation.

Findings

Quantum limit cycle exists at a purely quantum level.

Limit cycle remains the same under forward and reverse protocols.

Illustrated using a one-dimensional Ising model.

Abstract

A quantum engine with n qubits performing thermodynamic cycles with two thermal reservoirs is presented. While such constructions have been aplenty, here we show the existence of what we term as "limit cycle" at a purely quantum level of description owing to the properties of superoperators governing the evolution of states. It is shown that the limit cycle is the same under forward and reverse protocol of cycle operations. This limit cycle becomes the basis of the quantum engine. One dimensional Ising model has been used to illustrate these ideas.