Work extraction via quantum nondemolition measurements of qubits in cavities: Non-Markovian effects

TL;DR

This paper demonstrates that frequent quantum nondemolition measurements can extract work from a system-bath interaction in non-Markovian environments, even without information gain or at zero temperature, highlighting a new quantum work resource.

Contribution

It introduces a novel method of work extraction using nondemolition measurements within non-Markovian baths, expanding quantum thermodynamics understanding.

Findings

Work can be extracted without information gain.

Work extraction is possible at zero bath temperature.

The method relies on bath memory effects.

Abstract

We show that frequent nondemolition measurements of a quantum system immersed in a thermal bath allow the extraction of work in a closed cycle from the system-bath interaction (correlation) energy, a hitherto unexploited work resource. It allows for work even if no information is gathered or the bath is at zero temperature, provided the cycle is within the bath memory time. The predicted work resource may be the basis of quantum engines embedded in a bath with long memory time, such as the electromagnetic bath of a high-Q cavity coupled to two-level systems.