Measurement of Stochastic Entropy Production

TL;DR

This paper experimentally measures the entropy production in a single two-level quantum system using fluorescence spectroscopy, validating theoretical relations for stochastic entropy in finite time trajectories.

Contribution

It provides the first direct experimental measurement of stochastic entropy production at the single-system level, confirming theoretical predictions.

Findings

Total entropy production obeys exact finite-time relations

Entropy can be decomposed into system and medium contributions

Experimental validation of stochastic thermodynamics principles

Abstract

Using fluorescence spectroscopy we directly measure entropy production of a single two-level system realized experimentally as an optically driven defect center in diamond. We exploit a recent suggestion to define entropy on the level of a single stochastic trajectory (Seifert, Phys. Rev. Lett. {\bf 95}, 040602 (2005)). Entropy production can then be split into one of the system itself and one of the surrounding medium. We demonstrate that the total entropy production obeys various exact relations for finite time trajectories.