Dresden 2011 – wissenschaftliches Programm
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DY: Fachverband Dynamik und Statistische Physik
DY 6: Quantum Dynamics, Decoherence, and Quantum Information I
DY 6.8: Vortrag
Montag, 14. März 2011, 16:00–16:15, ZEU 255
The Periodically Driven Dicke Model — •Victor Manuel Bastidas Valencia1, John Henry Reina2, Benjamin Regler1, Clive Emary1, and Tobias Brandes1 — 1Institut für Theoretische Physik, Technische Universität Berlin, Hardenbergstr. 36, 10623 Berlin, Deutschland — 2Universidad del Valle, Departamento de Fisica, A. A. 25360, Cali, Colombia
We study the nonequilibrium quantum phase transition (NEQPT) in a periodically-driven Dicke model. The normal-superradiant quantum phase transition in equilibrium conditions has been extensively studied [1,2]. However, the physics of superradiance in nonequilibrium conditions is not completely understood. In order to investigate the nonequilibrium properties of the quantum phase transition in the case of time-dependent atom-field coupling we derive two effective time-independent Hamiltonians by using the rotating wave approximation (RWA) and perturbation theory in the high-driving frequency regime. These effective Hamiltonians allow the description of the quantum phase transition using the well known formulation of quantum phase transitions in time-independent systems. However, in the nonequilibrium case, the character of the quantum phase transition is dynamical and the spectrum of the effective Hamiltonians corresponds to the quasienergy spectrum of the original driven system in perturbation theory.
[1] R. H. Dicke, Phys. Rev. 93, 99 (1954).
[2] C. Emary and T. Brandes, Phys. Rev. E 67, 066203 (2003).