Journal article

Density ripples in expanding low-dimensional gases as a probe of correlations

  • Imambekov, A. Department of Physics, Yale University, New Haven USA - Department of Physics and Astronomy, Rice University, Houston, USA
  • Mazets, I. E. Atominstitut, Fakultät für Physik, TU-Wien, Austria - Ioffe Physico-Technical Institute, St. Petersburg, Russia
  • Petrov, D. S. Laboratoire Physique Théorique et Modéles Statistique, Université Paris Sud, Orsay, France - Russian Research Center Kurchatov Institute, Moscow, Russia
  • Gritsev, Vladimir Physics Department, University of Fribourg, Switzerland
  • Manz, S. Atominstitut, Fakultät für Physik, TU-Wien, Austria
  • Hofferberth, S. Department of Physics, Harvard University, Cambridge, USA
  • Schumm, T. Atominstitut, Fakultät für Physik, TU-Wien, Austria - Wolfgang Pauli Institute, University of Vienna Austria
  • Demler, Eugene Department of Physics, Harvard University, Cambridge, USA
  • Schmiedmayer, J. Atominstitut, Fakultät für Physik, TU-Wien, Austria
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    09.09.2009
Published in:
  • Physical Review A. - 2009, vol. 80, p. 033604
English We investigate theoretically the evolution of the two-point density correlation function of a low-dimensional ultracold Bose gas after release from a tight transverse confinement. In the course of expansion thermal and quantum fluctuations present in the trapped systems transform into density fluctuations. For the case of free ballistic expansion relevant to current experiments, we present simple analytical relations between the spectrum of “density ripples” and the correlation functions of the original confined systems. We analyze several physical regimes, including weakly and strongly interacting one-dimensional (1D) Bose gases and two-dimensional (2D) Bose gases below the Berezinskii-Kosterlitz-Thouless (BKT) transition. For weakly interacting 1D Bose gases, we obtain an explicit analytical expression for the spectrum of density ripples which can be used for thermometry. For 2D Bose gases below the BKT transition, we show that for sufficiently long expansion times the spectrum of the density ripples has a self-similar shape controlled only by the exponent of the first-order correlation function. This exponent can be extracted by analyzing the evolution of the spectrum of density ripples as a function of the expansion time.
Faculty
Faculté des sciences
Department
Physique
Language
  • English
Classification
Physics
License
License undefined
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Persistent URL
https://folia.unifr.ch/unifr/documents/301422
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