Berlin 2015 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 26: Quantum Dynamics, Decoherence and Quantum Information (jointly with DY)

TT 26.12: Talk

Monday, March 16, 2015, 18:00–18:15, BH-N 334

Dynamics of the dissipative Dicke Model for a large number of atoms — •Christos Bokas, Björn Kubala, and Joachim Ankerhold — Institute for Complex Quantum Systems, Ulm University, Ulm, Germany

The Dicke Hamiltonian is used to model the coupling of a cloud of atoms to a harmonic oscillator mode. In the thermodynamic limit, a phase transition occurs when increasing the coupling strength, shifting the system from a ’normal’ to a ’superradiant’ state, which exhibits strong correlations between the two subsystems.

Dynamics close to this equilibrium state is described by the well-known Holstein-Primakov approach [1] in terms of two effective Hamiltonians containing two coupled harmonic degrees of freedom.

We aim to describe the full coherent and dissipative dynamics by deriving a mapping to a single effective potential valid for a large number of atoms. Starting from a highly excited atomic state, oscillations of excitations between atoms and cavity and the eventual decay to equilibrium can, hence, be studied within this approach.

[1] C. Emary and T. Brandes, Phys. Rev. E 67, 066203 (2003).