Regensburg 2010 – wissenschaftliches Programm
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DY: Fachverband Dynamik und Statistische Physik
DY 1: Statistical Physics (general) I
DY 1.2: Vortrag
Montag, 22. März 2010, 10:30–10:45, H47
Calculating statistical field theories beyond the mean-field level by employing self-interaction renormalized actions — •Stephan Baeurle1, Garii Efimov2, and Evgenij Nogovitsin3 — 1Institut für Physikalische und Theoretische Chemie, Universität Regensburg, Universitätstr. 31, 93053 Regensburg, Germany — 2Bogoliubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, 141980 Dubna, Russia — 3Institute of Solution Chemistry, Russian Academy of Sciences, 153045 Ivanovo, Russia
Mean-field theories are widely used as comparative theoretical tools throughout all areas of natural and engineering sciences. They are capable in many instances to deliver useful insights in properties and behavior of multi-body systems at relatively moderate computational costs. However, there are a multitude of cases where the mean-field approach provides either inaccurate or even qualitatively wrong results. In this presentation we introduce a new beyond mean field calculation approach based on an alternative exact formulation of the partition function integral, which relies on the method of Gaussian equivalent representation GER originally developed in quantum field theory. With this new approach, we remove divergent contributions from the action, related to particle self-interaction, by employing the concept of normal product in conjunction with Cauchy's integral theorem. We show that the related thermodynamic and structural quantities possess better approximation characteristics and statistical convergence properties in Monte-Carlo sampling, than the ones derived from the original field-theoretic formulation of the partition function integral.