Dresden 2011 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 16: Statistical Physics II

DY 16.2: Talk

Wednesday, March 16, 2011, 10:45–11:00, HÜL 186

Real-Time Monte Carlo Simulations for a two-level-system within a Sub-Ohmic environment — •Denis Kast¹, Charlotte Escher², and Joachim Ankerhold¹ — ¹Institut für Theoretische Physik, Universität Ulm — ²Physikalisches Institut, Albert-Ludwigs-Universität Freiburg

The two-level system (TLS) coupled to a dissipative environment (spin-boson-model) is studied within the numerically exact path integral Monte-Carlo (PIMC) approach. Well studied in all ranges of parameter space (e.g. temperature, coupling strength, cut-off frequency) is the real-time dynamics for ohmic spectral bath densities including a phase transition from a delocalized to localised regime at T=0. Much less is known for the sub-ohmic case which has recently gained considerable interest. Most studies, however, have been restricted to properties at T=0. Here we present real-time PIMC simulations for finite temperatures over a wide domain of parameters. Out of the TLS-dynamics estimates for the critical coupling strengths of the transition delocalized/localized are derived. Comparisons with alternative methods at T=0 are discussed.