Play. Pause. Rewind. Measuring local entropy production and extractable work in active matter

TL;DR

This paper introduces a local measure of entropy production in active matter systems, linking it to work extractability, validated through theory, simulations, and experiments involving active particles and bacteria.

Contribution

It presents a novel local entropy production measure and a protocol to estimate it, connecting microscopic irreversibility to macroscopic work in active matter.

Findings

Local entropy production correlates with extractable work.

Time-reversal asymmetry influences macroscopic behavior.

Method validated in experiments with active particles and bacteria.

Abstract

Time-reversal symmetry breaking and entropy production are universal features of nonequilibrium phenomena. Despite its importance in the physics of active and living systems, the entropy production of systems with many degrees of freedom has remained of little practical significance because the high-dimensionality of their state space makes it difficult to measure. Here we introduce a local measure of entropy production and a numerical protocol to estimate it. We establish a connection between the entropy production and extractability of work in a given region of the system and show how this quantity depends crucially on the degrees of freedom being tracked. We validate our approach in theory, simulation, and experiments by considering systems of active Brownian particles undergoing motility induced phase separation, as well as active Brownian particles and E. Coli in a rectifying device in which the time-reversal asymmetry of the particle dynamics couples to spatial asymmetry to reveal its effects on a macroscopic scale.