Renormalization of the superfluid density in the two-dimensional BCS-BEC crossover

G. Bighin, L. Salasnich, International Journal of Modern Physics B 32 (2018) 1840022.


Journal Article | Published | English
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Abstract
We analyze the theoretical derivation of the beyond-mean-field equation of state for 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.
Publishing Year
Date Published
2018-07-10
Journal Title
International Journal of Modern Physics B
Volume
32
Issue
17
Page
1840022
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Cite this

Bighin G, Salasnich L. Renormalization of the superfluid density in the two-dimensional BCS-BEC crossover. International Journal of Modern Physics B. 2018;32(17):1840022. doi:10.1142/S0217979218400222
Bighin, G., & Salasnich, L. (2018). Renormalization of the superfluid density in the two-dimensional BCS-BEC crossover. International Journal of Modern Physics B, 32(17), 1840022. https://doi.org/10.1142/S0217979218400222
Bighin, Giacomo, and Luca Salasnich. “Renormalization of the Superfluid Density in the Two-Dimensional BCS-BEC Crossover.” International Journal of Modern Physics B 32, no. 17 (2018): 1840022. https://doi.org/10.1142/S0217979218400222.
G. Bighin and L. Salasnich, “Renormalization of the superfluid density in the two-dimensional BCS-BEC crossover,” International Journal of Modern Physics B, vol. 32, no. 17, p. 1840022, 2018.
Bighin G, Salasnich L. 2018. Renormalization of the superfluid density in the two-dimensional BCS-BEC crossover. International Journal of Modern Physics B. 32(17), 1840022.
Bighin, Giacomo, and Luca Salasnich. “Renormalization of the Superfluid Density in the Two-Dimensional BCS-BEC Crossover.” International Journal of Modern Physics B, vol. 32, no. 17, World Scientific Publishing, 2018, p. 1840022, doi:10.1142/S0217979218400222.

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