Linear response of hydrodynamically-coupled particles under a nonequilibrium reservoir

Abstract

A recent experiment driving colloids electromagnetically, by Bérut et al. [2014 Europhys. Lett. 107, 60004], is an ideal paradigm for illustrating a linear response theory for nonequilibrium overdamped systems including hydrodynamic interactions and, unusually, a reservoir itself out of equilibrium. Indeed, in this setup one finds a nonequilibrium environment in which the mobility and diffusivity of free particles are not simply proportional to each other. We derive both the response to a mechanical forcing and to temperature variations in terms of correlations between an observable and a path-weight action. The time-antisymmetric component of the latter turns out not to be simply proportional to the heat flowing into the environment. These results are visualized with simulations resembling conditions and protocols easily realizable in the experiment, thereby tracing a path for experimental verifications of the theory.

24 pages, 3 figures; added footnote, removed incorrect citation, updated a reference, fixed overall sign in Eqs. (30) and (34)

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Cited by in corpus (5)

• Nonequilibrium temperature response for stochastic overdamped systems
• A general fluctuation-response relation for noise variations and its application to driven hydrodynamic experiments
• Thermal response of nonequilibrium RC-circuits
• Irreversibility of mesoscopic processes with hydrodynamic interactions
• Thermal response of a Fermi-Pasta-Ulam chain with Andersen thermostats