Berlin 2005 – wissenschaftliches Programm

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DY: Dynamik und Statistische Physik

DY 51: Einstein Symposium Brownian Motion, Diffusion and Beyond (SYBM) – Contributed Talks II

DY 51.2: Vortrag

Mittwoch, 9. März 2005, 10:30–10:45, TU H2032

Jarzynski’s relation: When is the work distribution a Gaussian? — •Thomas Speck and Udo Seifert — II. Institut für Theoretische Physik, Universität Stuttgart

Jarzynski’s relation constrains the distribution of dissipated work spent in externally driven non-equilibrium processes like the mechanical stretching of biopolymers. Using this constraint, free energy differences can be extracted from non-equilibrium data. If the work distribution is a Gaussian, its mean and variance are related. We prove constructively that for slow driving this distribution is always Gaussian even for an underlying non-linear Langevin equation of motion [1]. For a linear Langevin equation, this distribution remains Gaussian even at fast driving. For this case, we determine its mean (and variance) as given by a non-local integral kernel [2]. This general result is illustrated for stretching Rouse polymers.
[1] T. Speck and U. Seifert, Phys. Rev. E, in press.
T. Speck and U. Seifert, Eur. Phys. J. B, submitted.