Dresden 2009 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 16: Stochastic Processes
BP 16.5: Vortrag
Mittwoch, 25. März 2009, 17:00–17:15, ZEU 260
Optimal potentials for temperature ratchets — •Florian Berger2, Tim Schmiedl1, and Udo Seifert1 — 1II. Institut für Theoretische Physik, Universität Stuttgart, 70550 Stuttgart — 2Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14424 Potsdam
Since the introduction by Feynman, temperature ratchets have served as a model for a microscopic heat engine which operates between two heat baths. More generally, directed transport of an overdamped Brownian particle can be induced along a periodic potential in a spatially periodic temperature profile. With a load force applied to the particle, this setup can perform as a heat engine. The dependence of the current on the potential evokes the question: What is the optimal shape of the potential that maximizes the current and thus the power output of the engine for a given load? Using variational calculus, we determine the optimal potential for a sinusoidal temperature profile analytically up to a numerical root search. We discuss the dependence of the optimal potential on scaled model parameters such as the temperature amplitude and the load force.