Self-propulsion protocols for swift non-equilibrium state transitions and enhanced cooling in active systems

TL;DR

This paper introduces a control framework for actively inducing rapid non-equilibrium state transitions in confined active matter by manipulating self-propulsion statistics, enabling more efficient cooling protocols.

Contribution

It defines the control space based on positivity and bounds on correlations, and demonstrates how initial states with negative correlations can accelerate cooling.

Findings

Non-stationary initial states enable faster state transitions.

Active cooling protocols outperform passive methods.

Speed-limits are imposed by positivity and correlation bounds.

Abstract

A control framework is proposed for inducing non-equilibrium state transitions in confined active matter, where the statistics of self-propulsion serve as the only control parameter. Positivity of the noise amplitudes and fundamental bounds on position-propulsion correlations define the admissible control space and impose speed-limits on transitions between non-equilibrium states. We show that non-stationary initial states facilitate additional speed-ups, corresponding to pre-loading the state with negative correlations. This enables active cooling protocols that outperform their passive counterparts.