Critical superfluid velocity in a trapped dipolar gas
| Autor: | Shai Ronen, John L. Bohn, Ryan Wilson |
|---|---|
| Rok vydání: | 2009 |
| Předmět: |
Quantum fluid
Physics Condensed Matter::Quantum Gases Condensed matter physics Condensed Matter::Other Direct numerical simulation General Physics and Astronomy FOS: Physical sciences Critical ionization velocity Roton law.invention Superfluidity law Quantum Gases (cond-mat.quant-gas) Quasiparticle Condensed Matter - Quantum Gases Superfluid helium-4 Bose–Einstein condensate |
| Zdroj: | Physical review letters. 104(9) |
| ISSN: | 1079-7114 |
| Popis: | We investigate the superfluid properties of a dipolar Bose-Einstein condensate (BEC) in a fully three-dimensional trap. Specifically, we calculate a superfluid critical velocity for this system by applying the Landau criterion to its discrete quasiparticle spectrum. We test this critical velocity by direct numerical simulation of condensate depletion as a blue-detuned laser moves through the condensate. In both cases, the presence of the roton in the spectrum serves to lower the critical velocity beyond a critical particle number. Since the shape of the dispersion, and hence the roton minimum, is tunable as a function of particle number, we thereby propose an experiment that can simultaneously measure the Landau critical velocity of a dipolar BEC and demonstrate the presence of the roton in this system. 5 pages, 4 figures, version accepted to PRL |
| Databáze: | OpenAIRE |
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