학술논문

How far from equilibrium is active matter?
Document Type
Working Paper
Source
Phys. Rev. Lett. 117, 038103 (2016)
Subject
Condensed Matter - Statistical Mechanics
Condensed Matter - Soft Condensed Matter
Language
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 visco-elastic bath but driven out of equilibrium by non-conservative forces, hence providing an energetic insight on the departure of active systems from equilibrium.
Comment: 5 pages, 2 figures