Max Planck Institute for Dynamics and Self-Organization -- Department for Nonlinear Dynamics and Network Dynamics Group
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Arbeitsgruppen-Seminar

Thursday, 17.07.2008 17:15 c.t.

Manyparticle and meanfield description of ultracold atoms in a leaking double-well trap

by Dr. Eva-Maria Graefe
from Technische Universität Kaiserslautern

Contact person: Ragnar Fleischmann

Location

Seminarraum Haus 2, 4. Stock (Bunsenstr.)

Abstract

Recently some attention has been paid to the description of decay, scattering and transport behaviour of Bose-Einstein condensatess phenomenologically described by effective non-Hermitian meanfield theories. However, a derivation of a meanfield approximation starting from a non-Hermitian manyparticle system seems to be still missing. In the present talk we therefore address this question for an open two-mode Bose-Hubbard Hamiltonian, which serves as a model for a BEC in a leaking double-well trap. Starting from the dynamics of operators, we derive a non-Hermitian meanfield description. The resulting generalized nonlinear Bloch dynamics is mainly influenced by the number and characteristics of the fixed points, whose dependence on the systems parameters is analysed in detail. We argue that the manyparticle manifestation of the different meanfield regimes is the occurrence of exceptional points in the many particle spectrum, whose structure is clarified using perturbational methods.

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