Nonequilibrium fluctuations in a resistor

TL;DR

This paper experimentally investigates nonequilibrium fluctuations in a resistor driven by a small current, demonstrating the validity of Fluctuation Theorems and their use in measuring dissipated power.

Contribution

It provides experimental validation of Fluctuation Theorems in an electrical system and shows how these theorems can be used to measure dissipation from fluctuation data.

Findings

FT are experimentally validated in a resistor system.

Fluctuation PDFs exhibit symmetry properties predicted by FT.

Dissipated power can be measured from fluctuation symmetry.

Abstract

In small systems where relevant energies are comparable to thermal agitation, fluctuations are of the order of average values. In systems in thermodynamical equilibrium, the variance of these fluctuations can be related to the dissipation constant in the system, exploiting the Fluctuation-Dissipation Theorem (FDT). In non-equilibrium steady systems, Fluctuations Theorems (FT) additionally describe symmetry properties of the probability density functions (PDFs) of the fluctuations of injected and dissipated energies. We experimentally probe a model system: an electrical dipole driven out of equilibrium by a small constant current $I$, and show that FT are experimentally accessible and valid. Furthermore, we stress that FT can be used to measure the dissipated power $\bar{\cal P}=RI^2$ in the system by just studying the PDFs symmetries.