Correlated escape of active particles across a potential barrier

TL;DR

This study investigates how active particles escape from a double-well potential, revealing non-monotonic escape times, the influence of activity persistence, and the effects of particle interactions on escape behavior.

Contribution

It introduces a comprehensive analysis of active particle escape dynamics, including a new theoretical framework for large persistence times and insights into multi-particle interactions.

Findings

Escape time shows non-monotonic dependence on persistence time.

Effective potential approach works for small persistence times.

Particle interactions can either facilitate or hinder escape depending on persistence.

Abstract

We study the dynamics of one-dimensional active particles confined in a double-well potential, focusing on the escape properties of the system, such as the mean escape time from a well. We first consider a single-particle both in near and far-from-equilibrium regimes by varying the persistence time of the active force and the swim velocity. A non-monotonic behavior of the mean escape time is observed with the persistence time of the activity, revealing the existence of an optimal choice of the parameters favoring the escape process. For small persistence times, a Kramers-like formula with an effective potential obtained within the Unified Colored Noise Approximation is shown to hold. Instead, for large persistence times, we developed a simple theoretical argument based on the first passage theory which explains the linear dependence on the escape time with the persistence of the active force. In the second part of the work, we consider the escape of two active particles mutually repelling. Interestingly, the subtle interplay of active and repulsive forces may lead to a correlation between particles favoring the simultaneous jump across the barrier. This mechanism cannot be observed in the escape process of two passive particles. Finally, we find that, in the small-persistence regime, the repulsion favors the escape, like in passive systems, in agreement with our theoretical predictions, while for large persistence times, the repulsive and active forces produce an effective attraction which hinders the barrier crossing.