# Subsonic critical velocity of a Bose-Einstein condensate at finite temperature

## Abstract

Based on the dielectric formalism in the generalized random phase approximation, we generalize the description of a Bose-Einstein 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-Einstein gas is lower than the sound velocity. The requirement of Galilean invariance essential to obtain an invariant result necessitates the use of a gapless and conserving approximation.

- Authors:

- Universitaet Duisburg-Essen, Universitaetsstrasse 5, 45117 Essen (Germany)
- (Belgium)

- Publication Date:

- OSTI Identifier:
- 20787147

- Resource Type:
- Journal Article

- Resource Relation:
- Journal Name: Physical Review. A; Journal Volume: 73; Journal Issue: 4; Other Information: DOI: 10.1103/PhysRevA.73.043612; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 74 ATOMIC AND MOLECULAR PHYSICS; BOSE-EINSTEIN CONDENSATION; BOSE-EINSTEIN GAS; CRITICAL VELOCITY; DIELECTRIC MATERIALS; FLUIDS; RANDOM PHASE APPROXIMATION; SOUND WAVES; SUPERFLUIDITY

### Citation Formats

```
Navez, Patrick, Labo Vaste-Stoffysica en Magnetisme, Katholieke Universiteit Leuven, Celestijnenlaan 200D, B-3001 Leuven, and Graham, Robert.
```*Subsonic critical velocity of a Bose-Einstein condensate at finite temperature*. United States: N. p., 2006.
Web. doi:10.1103/PHYSREVA.73.0.

```
Navez, Patrick, Labo Vaste-Stoffysica en Magnetisme, Katholieke Universiteit Leuven, Celestijnenlaan 200D, B-3001 Leuven, & Graham, Robert.
```*Subsonic critical velocity of a Bose-Einstein condensate at finite temperature*. United States. doi:10.1103/PHYSREVA.73.0.

```
Navez, Patrick, Labo Vaste-Stoffysica en Magnetisme, Katholieke Universiteit Leuven, Celestijnenlaan 200D, B-3001 Leuven, and Graham, Robert. Sat .
"Subsonic critical velocity of a Bose-Einstein condensate at finite temperature". United States.
doi:10.1103/PHYSREVA.73.0.
```

```
@article{osti_20787147,
```

title = {Subsonic critical velocity of a Bose-Einstein condensate at finite temperature},

author = {Navez, Patrick and Labo Vaste-Stoffysica en Magnetisme, Katholieke Universiteit Leuven, Celestijnenlaan 200D, B-3001 Leuven and Graham, Robert},

abstractNote = {Based on the dielectric formalism in the generalized random phase approximation, we generalize the description of a Bose-Einstein 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-Einstein gas is lower than the sound velocity. The requirement of Galilean invariance essential to obtain an invariant result necessitates the use of a gapless and conserving approximation.},

doi = {10.1103/PHYSREVA.73.0},

journal = {Physical Review. A},

number = 4,

volume = 73,

place = {United States},

year = {Sat Apr 15 00:00:00 EDT 2006},

month = {Sat Apr 15 00:00:00 EDT 2006}

}

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