Distribution of Entropy Production in a Single-Electron Box

TL;DR

This study experimentally measures the distribution of microscopic entropy production in a non-equilibrium single-electron box, confirming fluctuation relations and revealing universal aspects of entropy in small thermodynamic systems.

Contribution

First experimental observation of microscopic entropy production distribution in a non-equilibrium single-electron system, validating fluctuation relations and universal formulas.

Findings

Verified fluctuation relations in a non-equilibrium system

Established a universal relation between coarse-grained and bare entropy production

Demonstrated the fundamental role of entropy production in small systems

Abstract

Recently, the fundamental laws of thermodynamics have been reconsidered for small systems. The discovery of the fluctuation relations has spurred theoretical and experimental studies on thermodynamics of systems with few degrees of freedom. The concept of entropy production has been extended to the microscopic level by considering stochastic trajectories of a system coupled to a heat bath. However, the experimental observation of the microscopic entropy production remains elusive. We measure distributions of the microscopic entropy production in a single-electron box consisting of two islands with a tunnel junction. The islands are coupled to separate heat baths at different temperatures, maintaining a steady thermal non-equilibrium. As Jarzynski equality between work and free energy is not applicable in this case, the entropy production becomes the relevant parameter. We verify experimentally that the integral and detailed fluctuation relations are satisfied. Furthermore, the coarse-grained entropy production from trajectories of electronic transitions is related to the bare entropy production by a universal formula. Our results reveal the fundamental roles of irreversible entropy production in non-equilibrium small systems.