Observation of Fluctuation-Dissipation-Theorem Violations in a Structural Glass

TL;DR

This study observed violations of the fluctuation-dissipation theorem in glycerol below its glass transition, indicating non-equilibrium energy flow between relaxation modes over extended timescales.

Contribution

First experimental evidence of FDT violations in a structural glass, revealing non-equilibrium dynamics persisting well beyond typical relaxation times.

Findings

FDT violations observed after quenching below Tg

Violations persisted up to 10^5 times the equilibration time

Excess energy flows from slower to faster modes

Abstract

The fluctuation-dissipation theorem (FDT), connecting dielectric susceptibility and polarization noise was studied in glycerol below its glass transition temperature Tg. Weak FDT violations were observed after a quench from just above to just below Tg, for frequencies above the alpha peak. Violations persisted up to 10^5 times the thermal equilibration time of the configurational degrees of freedom under study, but comparable to the average relaxation time of the material. These results suggest that excess energy flows from slower to faster relaxing modes.