Work measurement as a generalized quantum measurement

TL;DR

This paper introduces a novel method for measuring work in quantum systems using a single generalized quantum measurement, enabling efficient sampling of work distribution and potential quantum computational applications.

Contribution

It demonstrates that work can be measured via a single POVM, simplifying the process and enabling new quantum algorithms for estimating free energies.

Findings

Work measurement can be achieved with a single POVM.

The method enables efficient sampling of work distribution.

Potential for quantum algorithms to estimate free energies.

Abstract

We present a new method to measure the work $w$ performed on a driven quantum system and to sample its probability distribution $P(w)$. The method is based on a simple fact that remained unnoticed until now: Work on a quantum system can be measured by performing a generalized quantum measurement at a single time. Such measurement, which technically speaking is denoted as a POVM (positive operator valued measure) reduces to an ordinary projective measurement on an enlarged system. This observation not only demystifies work measurement but also suggests a new quantum algorithm to efficiently sample the distribution $P(w)$. This can be used, in combination with fluctuation theorems, to estimate free energies of quantum states on a quantum computer.