Work measurement as a generalized quantum measurement

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.

4 pages

References in corpus (3)

• Fluctuation theorems: Work is not an observable
• Employing trapped cold ions to verify the quantum Jarzynski equality
• Fluctuation theorems for continuously monitored quantum fluxes

Cited by in corpus (3)

• Nonequilibrium fluctuations in quantum heat engines: Theory, example, and possible solid state experiments
• Quantum Otto cycle with inner friction: finite-time and disorder effects
• Measuring work and heat in ultracold quantum gases