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DY: Fachverband Dynamik und Statistische Physik

DY 16: Statistical Physics 3 - organized by Barbara Drossel (Darmstadt), Sabine Klapp (Berlin) and Thomas Speck (Mainz)

DY 16.3: Vortrag

Montag, 22. März 2021, 17:10–17:30, DYb

Evaluation of memory effects at phase transitions — •Hugues Meyer — Department of Theoretical Physics and Center for Biophysics, Universität des Saarlandes, Saarbrücken, Germany

Modeling the dynamics of order parameters at phase transitions is often done in terms of stochastic equations of motion but there is to this day no consensus about a systematic strategy to tackle this problem. In particular, the detailed structure of the equations that needs to be used is still debated. Motivated by recent works on crystal nucleation, we propose to describe the dynamics of phase transitions in terms of a non-stationary Generalized Langevin Equation for the order parameter. By construction, this equation is non-local in time, i.e. it involves memory effects whose intensity is governed by a memory kernel. Here we do not aim at investigating the physical origin of memory effects at phase transitions in general, but rather to relate the extent of the memory kernel to quantities that are experimentally observed such as the induction time and the duration of the phase transformation process. Using a simple kinematic model and a recently developed numerical procedure, we show that the extent of the memory kernel is positively correlated with the duration of the transition and of the same order of magnitude, while the distribution of induction times does not have an effect. This theoretical observation is finally tested at the example of several model systems.