Nonequilibrium Phenomena in Driven and Active Coulomb Field Theories

TL;DR

This paper explores novel nonequilibrium phenomena in Coulomb-like systems, revealing long-range correlations and critical behaviors driven by external forces and active responses, expanding understanding of long-range interactions in nonequilibrium statistical physics.

Contribution

It introduces two new examples of nonequilibrium behaviors in Coulomb systems, highlighting the effects of external driving and activity on long-range interactions.

Findings

Unscreened long-range correlations in driven electrolytes

Fluctuation-induced forces in Casimir geometry

Out-of-equilibrium critical behavior in self-chemotactic models

Abstract

The classical Coulomb gas model has served as one of the most versatile frameworks in statistical physics, connecting a vast range of phenomena across many different areas. Nonequilibrium generalisations of this model have so far been studied much more scarcely. With the abundance of contemporary research into active and driven systems, one would naturally expect that such generalisations of systems with long-ranged Coulomb-like interactions will form a fertile playground for interesting developments. Here, we present two examples of novel macroscopic behaviour that arise from nonequilibrium fluctuations in long-range interacting systems, namely (1) unscreened long-ranged correlations in strong electrolytes driven by an external electric field and the associated fluctuation-induced forces in the confined Casimir geometry, and (2) out-of-equilibrium critical behaviour in self-chemotactic models that incorporate the particle polarity in the chemotactic response of the cells. Both of these systems have nonlocal Coulomb-like interactions among their constituent particles, namely, the electrostatic interactions in the case of the driven electrolyte, and the chemotactic forces mediated by fast-diffusing signals in the case of self-chemotactic systems. The results presented here hint to the rich phenomenology of nonequilibrium effects that can arise from strong fluctuations in Coulomb interacting systems, and a rich variety of potential future directions, which are discussed.