Condensation of quasiparticles and density modulation beyond the superfluid critical velocity

András Süto, P. Szépfalusy

Research output: Contribution to journalArticle

Abstract

We extend our earlier study of the ground state of a bosonic quasiparticle Hamiltonian by investigating the effect of a constant external velocity field. Below a critical velocity the ground state is a quasiparticle vacuum, corresponding to a pure superfluid phase at zero temperature. Beyond the critical velocity energy minimization leads to a macroscopic condensation of quasiparticles at a nonzero wave vector kv parallel to the velocity v. Simultaneously, physical particles also undergo a condensation at k v and, to a smaller extent, at -kv. Together with the Bose-Einstein condensation at k=0, the three coexisting condensates give rise to density modulations of wave vectors kv and 2kv. For larger |v| our model predicts a bifurcation of kv with corresponding two pure condensates and no density modulation.

Original languageEnglish
Article number043640
JournalPhysical Review A
Volume88
Issue number4
DOIs
Publication statusPublished - Oct 29 2013

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critical velocity
condensation
modulation
condensates
ground state
velocity distribution
vacuum
optimization
temperature
energy

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

Cite this

Condensation of quasiparticles and density modulation beyond the superfluid critical velocity. / Süto, András; Szépfalusy, P.

In: Physical Review A, Vol. 88, No. 4, 043640, 29.10.2013.

Research output: Contribution to journalArticle

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