Fluctuation theorem and linear response in a non-equilibrium bath

by Ralf Eichhorn (Nordita)

Tuesday 7 Nov 2017, 13:30 → 14:30 Europe/Stockholm

112:028

In the typical setting of non-equilibrium Brownian motion, a small object of interest is in contact with a heat bath, which itself has equilibrium properties. Examples are colloidal particles or small biological complexes which are suspended in an aqueous solution at room temperature. Stochastic thermodynamics as a sub-field of statistical mechanics has been developed to characterize the properties of such systems, by extending the notions of equilibrium thermodynamics to the non-equilibrium realm. While the system can be driven far away from equilibrium with its environment, the central results in stochastic thermodynamics are obtained under the assumption that the thermal environment is always at equilibrium.
On the other hand, experimental progress in recent years has opened the possibility to study conditions under which the ``thermal’’ bath itself has non-equilibrium properties, for instance, due to permanent energy conversion taking place in the bath. These experimental advances are complemented by theoretical attempts to find a thermodynamics-like theory for such situations. We here study a simple model of a non-equilibrium bath and derive an exact fluctuation theorem for the ``generalized entropy production” in the non-equilibrium bath. We also show that this ``generalized entropy production” is relevant for the linear response behavior of the system, and that it might be interpreted in information-theoretic terms.
This is unfinished work in progress, the talk will therefore be very informal with hopefully many discussions.