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arXiv:1206.7066 · Physical Review A

Landau critical velocity in weakly interacting Bose gases

Gordon Baym, C. J. Pethick

Published Aug 2, 2012• 43 citations
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Abstract

The flow of a uniform Bose gas at speeds greater than the Landau critical velocity ${v}_{c}$ does not necessarily destroy superfluidity, but rather needs only to lead to a decrease of the superfluid mass density ${\ensuremath{\rho}}_{s}$. Analyzing a weakly interacting Bose gas with a finite-range interparticle interaction that leads to a Landau critical velocity at nonzero quasiparticle momentum, we explicitly construct the (nonuniform) condensate for fluid flow faster than ${v}_{c}$ and calculate the accompanying decrease in ${\ensuremath{\rho}}_{s}$. We briefly comment on the relation of the physics to other problems in superfluids, e.g., solitons and vortices in Bose-Einstein condensates, and critical currents in superconductors.

DOI
10.1103/physreva.86.023602

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The flow of a uniform Bose gas at speeds greater than the Landau critical velocity vc{v}_{c}vc​ does not necessarily destroy superfluidity, but rather needs only to lead to a decrease of the superfluid mass density \ensuremathρs{\ensuremath{\rho}}_{s}\ensuremathρs​. Analyzing a weakly interacting Bose gas with a finite-range interparticle interaction that leads to a Landau critical velocity at nonzero quasiparticle momentum, we explicitly construct the (nonuniform) condensate for fluid flow faster than vc{v}_{c}vc​ and calculate the accompanying decrease in \ensuremathρs{\ensuremath{\rho}}_{s}\ensuremathρs​. We briefly comment on the relation of the physics to other problems in superfluids, e.g., solitons and vortices in Bose-Einstein condensates, and critical currents in superconductors.
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