Regensburg 2013 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 7: Poster I

DY 7.2: Poster

Montag, 11. März 2013, 17:30–19:30, Poster C

Quantum-classical correspondence in the dynamics of the Dicke model — •Lutz Bakemeier, Andreas Alvermann, and Holger Fehske — Institut für Physik, Ernst-Moritz-Arndt Universität Greifswald, Deutschland

The Dicke model describes an ensemble of two-level systems coupled to a quantum oscillator. It shows several interesting properties in its classical limits. While the ground state features a quantum phase transition, the classical dynamics shows a transition from regular to chaotic motion.

We consider the question how the signatures of the classical model evolve in the quantum model when the classical limit is approached. Based on Chebyshev expansion and kernel polynomial numerical methods we give an overview of the quantum-classical correspondence observable in the dynamical spectral functions, the time evolution of individual states, and the global dynamics in phase space. We analyze the excitations in the dynamical spectral function which correspond to the collective modes of the classical model characterizing the quantum phase transition. For the global dynamics we discuss a quantum equivalent to the classical Poincaré surface of section on phase space. This quantity shows how the systems eigenstates localize on different parts of the energy shell and thus adequately describes the transition from regular to chaotic motion.