Eur. Phys. J. Special Topics 217, 189-195 (2013)
https://doi.org/10.1140/epjst/e2013-01768-4

Regular Article

Critical velocity of antiferromagnetic spin-1 Bose-Einstein condensates at finite temperature

Institute for Solid State Physics and Optics, Wigner Research Centre, Hungarian Academy of Sciences, PO Box 49, 1525 Budapest, Hungary

^a e-mail: szirmai.gergely@wigner.mta.hu

Received: 7 September 2012
Revised: 15 January 2013
Published online: 11 March 2013

Abstract

We study the instability of a moving spinor Bose-Einstein condensate when the speed of flow reaches the critical velocity. This we identify on the basis of Landau's criterion, i.e. the velocity above which some elementary excitation energy becomes negative. We show that the first-to-become unstable excitations are spin-carrying quasiparticles. We also discuss the temperature dependence of the critical velocity in a more advanced mean-field approximation.