On the transient fluctuation dissipation theorem after a quench at a critical point
Université de Lyon Laboratoire de Physique, École Normale Supérieure, C.N.R.S. UMR5672 46 Allée d'Italie, 69364 Lyon, France
Received: 23 April 2015
Accepted: 17 August 2015
The Modified Fluctuation Dissipation Theorem (MFDT) proposed by G. Verley et al. (EPL, 93 (2011) 10002) for non-equilibrium transient states is experimentally studied. We apply MFDT to the transient relaxation dynamics of the director of a liquid crystal after a quench close to the critical point of the Fréedericksz Transition (FrTr), which has several properties of a second-order phase transition driven by an electric field. Although the standard Fluctuation Dissipation Theorem (FDT) is not satisfied, because the system is strongly out of equilibrium, the MFDT is perfectly verified during the transient in a system which is only partially described by a Landau-Ginzburg (LG) equation, to which our observations are compared. The results can be useful in the study of material aging.
PACS: 05.40.-a – Fluctuation phenomena, random processes, noise, and Brownian motion / 05.70.Jk – Critical point phenomena / 64.60.-i – General studies of phase transitions
© EPLA, 2015