Nonperturbative dynamical many-body theory of a Bose-Einstein condensate

• Verfasst von: Gasenzer, Thomas [VerfasserIn]
• Verfasst von: Berges, Jürgen [VerfasserIn]
• Verfasst von: Schmidt, Michael G. [VerfasserIn]
• Verfasst von: Seco, Marcos [VerfasserIn]
• Titel: Nonperturbative dynamical many-body theory of a Bose-Einstein condensate
• Verf.angabe: Thomas Gasenzer, Juergen Berges, Michael G. Schmidt, and Marcos Seco, Institut für Theoretische Physik, Universität Heidelberg, Philosophenweg 16, 69120 Heidelberg, Germany
• Fussnoten: Gesehen am 06.03.2018
• Titel Quelle: Enthalten in: De.arxiv.org
• Jahr Quelle: 2005
• Band/Heft Quelle: (2005) Artikel-Nummer 0507480, 21 Seiten
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 1570429294

Abstract

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 non-perturbative 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 non-equilibrium quasistationary state and discuss the possibility to attribute an effective temperature to it. The approach to thermal equilibrium is found to be extremely slow.