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DY: Fachverband Dynamik und Statistische Physik

DY 28: Statistical Physics far from Equilibrium

DY 28.7: Talk

Thursday, March 17, 2011, 12:00–12:15, HÜL 186

Non-perturbative renormalization of a diffusion-limited decay process — •Anton Winkler and Erwin Frey — Arnold Sommerfeld Center and CeNS, Department of Physics, Ludwig-Maximilians-Universität München, Theresienstraße 37, 80333 München, Germany

Many quantitative results for stochastic processes are restricted to one dimension, where a plethora of methods is available. However, in higher dimensions they often fail. Furthermore, the major part of renormalization group analysis focuses on low dimensions, i.e. lower than or equal to the upper critical dimension. For magnetic O(n) models this is of course very reasonable since in this case the upper critical dimension is four.

In our work we have studied the decay process A+A → 0 in the framework of reaction diffusion processes. The critical dimension of our decay process is two. In three dimensions, fluctuations are not strong enough to obliterate the microscopic structure of space and the shape of the particles. This poses a problem to the usual perturbative approach because it works best for studying universal features.

Our non-perturbative approach is known to cope also with non-universal properties. It allowed us to tackle the intriguing question of how the microscopic structure enters the dynamics of the process in three and higher dimensions by providing exact results for the non-equilibrium Gibbs energy.