Dresden 2014 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
DY: Fachverband Dynamik und Statistische Physik
DY 10: Nonlinear Stochastic Systems
DY 10.6: Vortrag
Dienstag, 1. April 2014, 10:45–11:00, ZEU 160
Critical manifold and tricritical point of nonlinear globally coupled systems with additive noise — •Rüdiger Kürsten1,2 and Ulrich Behn1 — 1Institut für Theoretische Physik, Universität Leipzig, Germany — 2International Max Planck Research School Mathematics in the Sciences, Leipzig, Germany
An infinite array of globally coupled overdamped constituents moving in a double-well potential under the influence of additive Gaussian white noise is closely related to a discretized version of the mean field ϕ4-Ginzburg-Landau model. The system exhibits a continuous phase transition from a symmetric phase to a symmetry broken phase [1]. The qualitative behavior is the same for higher order saturation terms ϕn, where n ≥ 6 is even. The critical point is calculated for strong and for weak noise, these limits are also bounds for the critical point. Introducing an additional nonlinearity, such that the potential can have up to three minima, leads to richer behavior. Then the parameter space divides in three regions, a region with a symmetric phase, a region with a phase of broken symmetry and a region where both phases coexist. The region of coexistence collapses into one of the others via a discontinuous phase transition whereas the transition between the symmetric phase and the phase of broken symmetry is continuous. The tricritical point where the three regions intersect, can be calculated for strong and for weak noise. These limiting values are the optimal bounds for the tricritical point.
[1] R. Kürsten, S. Gütter, U. Behn, Phys. Rev. E 88, 022114 (2013)