Two-point measurement of entropy production from the outcomes of a single experiment with correlated photon pairs

TL;DR

This paper demonstrates a quantum fluctuation theorem by directly measuring entropy production from entangled photon pairs in an optical experiment, avoiding destructive detection and enabling precise non-equilibrium thermodynamics analysis.

Contribution

It introduces a novel experimental method to directly measure entropy production in quantum systems using entangled photons and two-point measurements.

Findings

Successful direct measurement of entropy production distribution

Implementation of a two-point measurement scheme with entangled photons

Avoidance of destructive photo-detection in quantum thermodynamics experiments

Abstract

Fluctuation theorems are one of the pillars of non-equilibrium thermodynamics. Broadly speaking, they concern the statistical distribution of quantities such as heat, work or entropy production. Quantum experiments, however, usually can only assess these distributions indirectly. In this letter we provide an experimental demonstration of a quantum fluctuation theorem where the distribution of entropy production is obtained directly from the outcomes (clicks) of an optical experiment. The setup consists of entangled photon pairs, one of which is sent an interferometer emulating a finite temperature amplitude damping device. Blocking specific paths of the interferometer is tantamount to restricting the possible configurations of the reservoir. And by measuring its entangled pair, we can directly implement the two-point measurement scheme, thus avoiding the destructive nature of photo-detection.