2005/10/06 by Patrick Navez, Robert Graham, Navez, Patrick +1
Engineering · Mathematics · Physics and Astronomy · #FOS: Physical sciences #Fluid Dynamics and Turbulent Flows #Gas Dynamics and Kinetic Theory #Phase Equilibria and Thermodynamics #Statistical Mechanics (cond-mat.stat-mech) #cond-mat.stat-mech
paper · pdf · doi:10.48550/arxiv.cond-mat/0510134
4 pages, 5 figures
arxiv created 2005/10/06 · openalex publication_date 2005/10/06 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Based on the dielectric formalism in the generalised random phase approximation, we generalise the description of a Bose condensed gas to allow for a relative velocity between the superfluid and normal fluid. In this model, we determine the critical velocity dynamically as the transition point between stable and unstable dynamics. Unlike the zero temperature case, at finite temperature the relative critical velocity of a dilute Bose gas is lower than the sound velocity. This result illustrates one relevant difference that exists between a conserving and gapless approximation and other approaches.