Regensburg 2010 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 6: Poster Session I

DY 6.19: Poster

Monday, March 22, 2010, 16:00–18:00, Poster B2

Quantitative analysis of fluctuations and irreversibility of optically trapped microspheres — •Olaf Ueberschär and Friedrich Kremer — Universität Leipzig; Institut für Experimentelle Physik I; Linnéstraße 5; D-04103 Leipzig

We present an experimental verification of several universal theorems of stochastic thermodynamics by means of optical tweezers. The theoretical and experimental investigation of this novel branch of modern thermodynamics promises in various ways to be of great benefit for the quantitative understanding and application of processes at the micro- and nanometre scale in the fields of physics, biochemistry and applied technology. Utilizing the formal framework established by U. Seifert and others around 2005 and following the experimental approaches of G. M. Wang et al. first published in 2002, we experimentally demonstrate the validity of several pertinent fluctuation theorems for special non-equilibrium states of optically trapped colloids. Our results in this context exceed the scope of Wang et al. 2002-2005 by a considerable margin. Fluctuation theorems which came into the focus of theoretical research about 15 years ago describe the emergence and quantitative evolution of macroscopic irreversibility from the microscopic point of view of stochastic thermodynamics. Moreover, we present a new method for the experimental determination of the radius and the temperature of a single optically trapped colloid by directly analyzing the thermal equilibriums fluctuations of the bead. This technique may be utilized for the optimisation of several other optical tweezers experiments which show a high requirement for quantitative precision.