Renormalization of the superfluid density in the two-dimensional BCS-BEC crossover
In: International Journal of Modern Physics B 32, 1840022 (2018); (2017)
Online
report
Zugriff:
We analyze the theoretical derivation of the beyond-mean-field equation of state for a two-dimensional gas of dilute, ultracold alkali-metal atoms in the Bardeen-Cooper-Schrieffer (BCS) to Bose-Einstein condensate (BEC) crossover. We show that at zero temperature our theory -- considering Gaussian fluctuations on top of the mean-field equation of state -- is in very good agreement with experimental data. Subsequently, we investigate the superfluid density at finite temperature and its renormalization due to the proliferation of vortex-antivortex pairs. By doing so, we determine the Berezinskii-Kosterlitz-Thouless (BKT) critical temperature -- at which the renormalized superfluid density jumps to zero -- as a function of the inter-atomic potential strength. We find that the Nelson-Kosterlitz criterion overestimates the BKT temperature with respect to the renormalization group equations, this effect being particularly relevant in the intermediate regime of the crossover.
Comment: 9 pages, 3 figures, presented to the International Conference "Electron correlation in superconductors and nanostructures", 17-20 August 2017, Odessa (Ukraine). To be published in the Proceedings
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Renormalization of the superfluid density in the two-dimensional BCS-BEC crossover
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Autor/in / Beteiligte Person: | Bighin, G. ; Salasnich, L. |
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Quelle: | International Journal of Modern Physics B 32, 1840022 (2018); (2017) |
Veröffentlichung: | 2017 |
Medientyp: | report |
DOI: | 10.1142/S0217979218400222 |
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