Eur. Phys. J. Plus (2016) 131: 363
https://doi.org/10.1140/epjp/i2016-16363-4

Regular Article

Depletion of the condensate in a dipolar Bose condensed gas in the presence of impurities

Department of Physics, University of Isfahan, 81746, Isfahan, Iran

^* e-mail: h.yavary@sci.ui.ac.ir

Received: 4 April 2016
Accepted: 26 September 2016
Published online: 19 October 2016

Abstract

The depletion of the condensate in a dipolar, trapped Bose condensed gas due to the contact, dipole-dipole interactions in the presence of impurities is investigated. By using the effective action in the mean-field approximation and Bogoliubov transformation for a homogeneous Bose gas, we will show that the quantum depletion due to the impurities is independent of the density of condensate and the system will collapse if the density of the impurities is large. For this case we will also show that the thermal depletion changes as T² for all interactions in the low-temperatures limit. For a trapped Bose condensed gas based on an extension of Bogoliubov theory to non-uniform systems at finite temperature and semiclassical approximation for the excited states, the depletion of the condensate is evaluated. In this case interactions are also responsible for a significant enhancement of the thermal and quantum excitations.