Nonperturbative dynamical many-body theory of a Bose-Einstein condensate
A dynamical many-body theory is presented which systematically extends beyond mean-field and perturbative quantum-field theoretical procedures. It allows us to study the dynamics of strongly interacting quantum-degenerate atomic gases. The nonperturbative approximation scheme is based on a systemati...
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| Hauptverfasser: | , , , |
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| Dokumenttyp: | Article (Journal) |
| Sprache: | Englisch |
| Veröffentlicht: |
5 December 2005
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| In: |
Physical review. A, Atomic, molecular, and optical physics
Year: 2005, Jahrgang: 72, Heft: 6 |
| ISSN: | 1094-1622 |
| DOI: | 10.1103/PhysRevA.72.063604 |
| Online-Zugang: | Verlag, Volltext: http://dx.doi.org/10.1103/PhysRevA.72.063604 Verlag, Volltext: https://link.aps.org/doi/10.1103/PhysRevA.72.063604 
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| Verfasserangaben: | Thomas Gasenzer, Jürgen Berges, Michael G. Schmidt, and Marcos Seco |
| Zusammenfassung: | A dynamical many-body theory is presented which systematically extends beyond mean-field and perturbative quantum-field theoretical procedures. It allows us to study the dynamics of strongly interacting quantum-degenerate atomic gases. The nonperturbative approximation scheme is based on a systematic expansion of the two-particle irreducible effective action in powers of the inverse number of field components. This yields dynamic equations which contain direct scattering, memory, and “off-shell” effects that are not captured by the Gross-Pitaevskii equation. This is relevant to account for the dynamics of, e.g., strongly interacting quantum gases atoms near a scattering resonance, or of one-dimensional Bose gases in the Tonks-Girardeau regime. We apply the theory to a homogeneous ultracold Bose gas in one spatial dimension. Considering the time evolution of an initial state far from equilibrium we show that it quickly evolves to a nonequilibrium quasistationary state and discuss the possibility to attribute an effective temperature to it. The approach to thermal equilibrium is found to be extremely slow. |
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| Beschreibung: | Gesehen am 10.12.2019 |
| Beschreibung: | Online Resource |
| ISSN: | 1094-1622 |
| DOI: | 10.1103/PhysRevA.72.063604 |