Dresden 2014 – scientific programme
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DY: Fachverband Dynamik und Statistische Physik
DY 40: Poster - Quantum Systems/ Stat. Phys./ Diffusive Process
DY 40.20: Poster
Thursday, April 3, 2014, 17:00–19:00, P3
Generalized Bose-Einstein condensation into multiple states in driven-dissipative systems — •Daniel Vorberg1,2, Waltraut Wustmann1,2, Roland Ketzmerick1,2, and André Eckardt1 — 1Max-Planck-Institut für Physik komplexer Systeme, Nöthnitzer Str. 38, 01187 Dresden, Germany — 2Technische Universität Dresden, Institut für Theoretische Physik, 01062 Dresden, Germany
Bose-Einstein condensation, the macroscopic occupation of a single quantum state, appears in equilibrium quantum statistical mechanics and persists also in the hydrodynamic regime close to equilibrium. Here we show that even when a degenerate Bose gas is driven into a steady state far from equilibrium, where the notion of a single-particle ground state becomes meaningless, Bose-Einstein condensation survives in a generalized form: the unambiguous selection of an odd number of states acquiring large occupations. Within mean-field theory, we derive a criterion for when a single and when multiple states are Bose selected in a non-interacting gas. We study the effect in several driven-dissipative model systems, and propose a quantum switch for heat conductivity based on shifting between one and three selected states.