Berlin 2012 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 28: Colloids and Complex Liquids I

CPP 28.8: Vortrag

Mittwoch, 28. März 2012, 17:15–17:30, C 130

How Hidden Degrees of Freedom affect Fluctuation-Theorems — •Jakob Mehl¹, Boris Lander², Udo Seifert², Clemens Bechinger¹, and Valentin Blickle¹ — ¹2. Physikalisches Institut, Universität Stuttgart, Germany — ²II. Institut für Theoretische Physik, Universität Stuttgart, Germany

Fluctuation-theorems (FT) are one of the few exact relations, which are valid for systems driven out of equilibrium. The connection between the free energy difference and the work done to a system, known as Jarzynski equality, is certainly the most prominent example of the FT for the total entropy production Δ s_tot. So far, experimental studies concentrated only on simple systems with one degree of freedom.

By combining paramagnetic colloidal particles and rotating laser tweezers, we study two nonequilibrium steady states, which can be coupled by an externally controlled magnetic field. Using video microscopy, we can simultaneously follow both particles’ nonequilibrium fluctuations with high accuracy. As derived from stochastic thermodynamics, all degrees of freedom have to be taken into account to maintain the FT of Δ s_tot. It is unknown whether such relations change, when only parts of the system are accessible, i.e. when in our experiment only the fluctuations of one particle are regarded. We show that for the prevailing majority of experimental cases the FT is only violated slightly, i.e. only linear correction terms contribute. For extreme situations, strong deviations are present and higher order terms are not longer negligible.