Fluctuation-Dissipation Theorem for Metastable Systems

TL;DR

This paper extends the fluctuation-dissipation theorem to metastable states in Markovian systems, valid before nucleation, supported by numerical simulations of a 2D Ising model.

Contribution

It introduces a generalized fluctuation-dissipation theorem applicable to metastable states, based on a superposition of ground and first excited states.

Findings

The theorem holds for times shorter than nucleation time.

Numerical validation with a 2D Ising model confirms the theoretical predictions.

Provides a framework for analyzing metastable systems using fluctuation-dissipation relations.

Abstract

We show that an appropriately defined fluctuation-dissipation theorem, connecting generalized susceptibilities and time correlation functions, is valid for times shorter than the nucleation time of the metastable state of Markovian systems satisfying detailed balance. This is done by assuming that such systems can be described by a superposition of the ground and first excited states of the master equation. We corroborate our results numerically for the metastable states of a two-dimensional Ising model.