Work fluctuations in a nematic liquid crystal

TL;DR

This paper investigates the fluctuations of work in a nematic liquid crystal near the Fréedericksz transition, confirming the Transient Fluctuation Theorem through experiments and theoretical analysis.

Contribution

It provides experimental validation of the Transient Fluctuation Theorem for work fluctuations in a liquid crystal system near a second-order phase transition.

Findings

Work fluctuations obey the Transient Fluctuation Theorem

Calibration of work using Fluctuation-Dissipation Theorem

Analytical justification of the fluctuation relation

Abstract

The orientation fluctuations of the director of a liquid crystal are measured, by a sensitive polarization interferometer, close to the Fr\'eedericksz transition, which is a second order transition driven by an electric field. Using mean field theory, we define the work injected into the system by a change of the electric field and we calibrate it using Fluctuation-Dissipation Theorem. We show that the work fluctuations satisfy the Transient Fluctuation Theorem. An analytical justification of this result is given. The open problems for the out of equilibrium case are finally discussed.