TitleBreakdown of effective temperature, power law interactions, and self-propulsion in a momentum-conserving active fluid
Publication TypeJournal Article
Year of Publication2019
AuthorsVishen ASingh, Prost J, Rao M
JournalPhys. Rev. E
Date Published12/2019

The simplest extensions of single-particle dynamics in a momentum-conserving active fluid—an active suspension of two colloidal particles or a single particle confined by a wall—exhibit strong departures from Boltzmann behavior, resulting in either a breakdown of an effective temperature description or a steady state with nonzero-entropy production rate. This is a consequence of hydrodynamic interactions that introduce multiplicative noise in the stochastic description of particle positions. This results in fluctuation-induced interactions that depend on distance as a power law. We find that the dynamics of activated colloids in a passive fluid, with stochastic forcing localized on the particle, is different from that of passive colloids in an active fluctuating fluid.