Eur. Phys. J. D 65, 19-24 (2011)
https://doi.org/10.1140/epjd/e2011-20066-7

Regular Article

Mean field effects on the scattered atoms in condensate collisions

¹ Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw, Poland
² The Andrzej Sołtan Institute for Nuclear Studies, Hoża 69, 00-681 Warsaw, Poland
³ Institute of Theoretical Physics, Physics Department, University of Warsaw, Hoża 69, 00-681 Warsaw, Poland

^a e-mail: marek.trippenbach@fuw.edu.pl

Received: 28 January 2011
Received in final form: 6 May 2011
Published online: 28 June 2011

Abstract

We consider the collision of two Bose Einstein condensates at supersonic velocities and focus on the halo of scattered atoms. This halo is the most important feature for experiments and is also an excellent testing ground for various theoretical approaches. In this study we find that the typical reduced Bogoliubov description, commonly used, is often not accurate in the region of parameters where experiments are performed. Surprisingly, besides the halo pair creation terms, one should take into account the evolving mean field of the remaining condensate and on-condensate pair creation. We present examples where the difference is clearly seen, and where the reduced description still holds. We also demostrate how to investigate separately the effects of various physical processes that influence the properties of the halo.