Berlin 2008 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 17: Poster I

DY 17.14: Poster

Dienstag, 26. Februar 2008, 16:00–18:00, Poster C

Phase transition of the sub-Ohmic spin-boson model — •Andre Winter and Heiko Rieger — Theoretische Physik, Universität des Saarlandes, PF 151150, D-66041 Saarbrücken

We study the spin-boson model in the sub-Ohmic case via path integral Monte Carlo methods. An algorithm in continuous imaginary time is applied, which avoids the usual Trotter-discretization, that is supposed to violate the quantum-classical mapping to the long-range Ising spin chain with algebraically decaying interaction. The phase transition between localized and delocalized phase is investigated by finite size scaling procedures, which take the corrections to scaling incoming due to long-range interaction into account. Critical Exponents are determined in both the mean-field and the non-classical regime, divided by the bath exponent of the spectral function.