Revisiting the quantum Szilard engine with fully quantum considerations

TL;DR

This paper analyzes the quantum Szilard engine considering level shifting, deriving expressions for heat and work, and distinguishing the roles of quantum versus classical information in energy extraction.

Contribution

It provides the first demonstration of how quantum and classical information differently affect heat absorption and work in the QSZE.

Findings

Quantum information contributes to heat absorption.

Classical information acts as a feedback controller.

In the limit of large well width or temperature, QSZE reduces to classical Szilard engine.

Abstract

By considering level shifting during the insertion process we revisit the quantum Szilard engine (QSZE) with fully quantum consideration. We derive the general expressions of the heat absorbed from thermal bath and the total work done to the environment by the system in a cycle with two different cyclic strategies. We find that only the quantum information contributes to the absorbed heat, and the classical information acts like a feedback controller and has no direct effect on the absorbed heat. This is the first demonstration of the different effects of quantum information and classical information for extracting heat from the bath in the QSZE. Moreover, when the well width $L\rightarrow \infty $ or the temperature of the bath $T\rightarrow \infty $ the QSZE reduces to the classical Szilard engine (CSZE), and the total work satisfies the relation $W_{\mathtt{tot}}=k_{B}T \mathtt{ln}2$ as obtained by Sang Wook Kim et al. [Phys. Rev. Lett. 106, 070401 (2011)] for one particle case.