Dresden 2006 – scientific programme

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AKB: Biologische Physik

AKB 24: Brownian Motion and Fluctuation Theorems

AKB 24.2: Talk

Thursday, March 30, 2006, 17:30–17:45, ZEU 255

Fluctuation-Dissipation Relations for Non-Equilibrium Steady States — •Thomas Speck and Udo Seifert — II. Institut für Theoretische Physik, Universität Stuttgart, Pfaffenwaldring 57/III, 70550 Stuttgart

In non-equilibrium, the fluctuation-dissipation theorem (FDT) relating the response function of an observable with its auto-correlation is violated. This violation has been studied intensely, especially in the context of aging systems and glasses, where it allows to define an effective temperature. In the case of colloidal systems, the heat permanently dissipated in order to maintain the violation of detailed balance has been identified as “housekeeping” heat [1,2]. As the crucial ingredient, this heat involves two aspects of the velocity, namely the actual velocity and the local mean velocity. Studying a paradigmatic single colloidal particle moving in a periodic potential, we discuss the close connection between the violation of the velocity FDT and the violation of detailed balance. We derive an explicit expression for this violation and illustrate our results with numerical simulations.

[1] T. Hatano and S. Sasa, Phys. Rev. Lett. 86, 3463 (2001)

[2] T. Speck and U. Seifert, J. Phys. A: Math. Gen. 38, L581 (2005)