Process interpretation of current entropic bounds

TL;DR

This paper interprets the quadratic entropic bounds for nonequilibrium currents in Markov diffusion processes as arising from an effective process that modifies only the non-reversible drift, clarifying their physical significance and relation to fluctuation theory.

Contribution

It provides a physical interpretation of the quadratic entropic bounds by linking them to an effective process altering only the non-reversible part of the dynamics.

Findings

The bound is produced by an effective process modifying the non-reversible drift.

The interpretation explains the relation to fluctuation relations and linear response.

Discussion of more general bounds and uncertainty relations for other quantities.

Abstract

We show for Markov diffusion processes that the quadratic entropic bound, recently derived for the rate functions of nonequilibrium currents, can be seen as being produced by an effective process that creates current fluctuations in a sub-optimal way by modifying only the non-reversible part of the drift or force of the process considered while keeping its reversible part constant. This provides a clear interpretation of the bound in terms of a physical process, which explains, among other things, its relation to the fluctuation relation, linear response, and reversible limits. The existence of more general quadratic bounds, and related uncertainty relations, for physical quantities other than currents is also discussed.