How Far from Equilibrium Is Active Matter?

Condensed Matter journal club

How Far from Equilibrium Is Active Matter?

Event details

Abstract

Active matter systems are driven out of thermal equilibrium by a lack of generalized Stokes-Einstein relation between injection and dissipation of energy at the microscopic scale. We consider such a system of interacting particles, propelled by persistent noises, and show that, at small but finite persistence time, their dynamics still satisfy a time-reversal symmetry. To do so, we compute perturbatively their steady-state measure and show that, for short persistent times, the entropy production rate vanishes. This endows such systems with an effective fluctuation-dissipation theorem akin to that of thermal equilibrium systems. Last, we show how interacting particle systems with viscous drags and correlated noises can be seen as in equilibrium with a viscoelastic bath but driven out of equilibrium by nonconservative forces, hence providing energetic insight into the departure of active systems from equilibrium.
PRL 117 article 038103 (2016)
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Authors

Étienne odor, Cesare Nardini, Michael E. Cates, Julien Tailleur, Paolo Visco, Frédéric van Wijland