Aging and effective temperatures near a critical point

TL;DR

This study investigates aging phenomena and effective temperatures in liquid crystals near a second-order transition, revealing critical slowing down and non-equilibrium properties through experimental measurements of fluctuations and responses.

Contribution

It provides experimental evidence of aging and effective temperature in liquid crystals near a critical point, highlighting the role of critical slowing down in non-equilibrium dynamics.

Findings

Liquid crystals exhibit aging behavior after a quench near the transition.

An effective temperature higher than the bath temperature is measurable.

Correlation and response functions follow power-law scaling over time.

Abstract

The orientation fluctuations of the director of a liquid crystal(LC) are measured after a quench near the Fr\'eedericksz transition, which is a second order transition driven by an electric field. We report experimental evidence that, because of the critical slowing down, the LC presents, after the quench, several properties of an aging system, such as power law scaling versus time of correlation and response functions. During this slow relaxation, a well defined effective temperature, much larger than the heat bath temperature, can be measured using the fluctuation dissipation relation.