Kinetic Equality for Susceptibility and Dynamical Activity

TL;DR

This paper introduces a universal kinetic equality linking susceptibilities and dynamical activity in nonequilibrium Markovian systems, unifying several existing kinetic relations.

Contribution

It presents a general kinetic equality (KSE) that encompasses known relations like the kinetic uncertainty relation and extends fluctuation theorems.

Findings

Derivation of a kinetic generalization of the fluctuation theorem

Establishment of an equality between susceptibility and observable-frenetic covariance

Unification of various kinetic relations under a single master equality

Abstract

We show a general kinetic equality for susceptibilities (KSE) of general fluctuating quantities and for the dynamical activity of nonequilibrium systems described by Markovian master equations. As special limiting cases, KSE reproduces the so-called kinetic uncertainty relation and its multivariate extension. To derive KSE, we also show a kinetic generalization of fluctuation theorem, and an equality for the susceptibility and the observable-frenetic covariance. Hence, KSE provides a master relation of these nonequilibrium kinetic relations.