抄録
The superfluid density is a fundamental quantity describing the response to a rotation as well as in two-fluid collisional hydrodynamics. We present extensive calculations of the superfluid density Ïs in the BCS-BEC crossover regime of a uniform superfluid Fermi gas at finite temperatures. We include strong-coupling or fluctuation effects on these quantities within a Gaussian approximation. We also incorporate the same fluctuation effects into the BCS single-particle excitations described by the superfluid order parameter Î" and Fermi chemical potential Î, using the NoziÃresâ€"Schmitt-Rink approximation. This treatment is shown to be necessary for consistent treatment of Ïs over the entire BCS-BEC crossover. We also calculate the condensate fraction Nc as a function of the temperature, a quantity which is quite different from the superfluid density Ïs. We show that the mean-field expression for the condensate fraction Nc is a good approximation even in the strong-coupling BEC regime. Our numerical results show how Ïs and Nc depend on temperature, from the weak-coupling BCS region to the BEC region of tightly bound Cooper pair molecules. In a companion paper, we derive an equivalent expression for Ïs from the thermodynamic potential, which exhibits the role of the pairing fluctuations in a more explicit manner.
| 元の言語 | English |
|---|---|
| 記事番号 | 033609 |
| ジャーナル | Physical Review A - Atomic, Molecular, and Optical Physics |
| 巻 | 75 |
| 発行部数 | 3 |
| DOI | |
| 出版物ステータス | Published - 2007 3 21 |
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ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
- Physics and Astronomy(all)
これを引用
Superfluid density and condensate fraction in the BCS-BEC crossover regime at finite temperatures. / Fukushima, N.; Ohashi, Yoji; Taylor, E.; Griffin, A.
：: Physical Review A - Atomic, Molecular, and Optical Physics, 巻 75, 番号 3, 033609, 21.03.2007.研究成果: Article
}
TY - JOUR
T1 - Superfluid density and condensate fraction in the BCS-BEC crossover regime at finite temperatures
AU - Fukushima, N.
AU - Ohashi, Yoji
AU - Taylor, E.
AU - Griffin, A.
PY - 2007/3/21
Y1 - 2007/3/21
N2 - The superfluid density is a fundamental quantity describing the response to a rotation as well as in two-fluid collisional hydrodynamics. We present extensive calculations of the superfluid density Ïs in the BCS-BEC crossover regime of a uniform superfluid Fermi gas at finite temperatures. We include strong-coupling or fluctuation effects on these quantities within a Gaussian approximation. We also incorporate the same fluctuation effects into the BCS single-particle excitations described by the superfluid order parameter Î" and Fermi chemical potential Î, using the NoziÃresâ€"Schmitt-Rink approximation. This treatment is shown to be necessary for consistent treatment of Ïs over the entire BCS-BEC crossover. We also calculate the condensate fraction Nc as a function of the temperature, a quantity which is quite different from the superfluid density Ïs. We show that the mean-field expression for the condensate fraction Nc is a good approximation even in the strong-coupling BEC regime. Our numerical results show how Ïs and Nc depend on temperature, from the weak-coupling BCS region to the BEC region of tightly bound Cooper pair molecules. In a companion paper, we derive an equivalent expression for Ïs from the thermodynamic potential, which exhibits the role of the pairing fluctuations in a more explicit manner.
AB - The superfluid density is a fundamental quantity describing the response to a rotation as well as in two-fluid collisional hydrodynamics. We present extensive calculations of the superfluid density Ïs in the BCS-BEC crossover regime of a uniform superfluid Fermi gas at finite temperatures. We include strong-coupling or fluctuation effects on these quantities within a Gaussian approximation. We also incorporate the same fluctuation effects into the BCS single-particle excitations described by the superfluid order parameter Î" and Fermi chemical potential Î, using the NoziÃresâ€"Schmitt-Rink approximation. This treatment is shown to be necessary for consistent treatment of Ïs over the entire BCS-BEC crossover. We also calculate the condensate fraction Nc as a function of the temperature, a quantity which is quite different from the superfluid density Ïs. We show that the mean-field expression for the condensate fraction Nc is a good approximation even in the strong-coupling BEC regime. Our numerical results show how Ïs and Nc depend on temperature, from the weak-coupling BCS region to the BEC region of tightly bound Cooper pair molecules. In a companion paper, we derive an equivalent expression for Ïs from the thermodynamic potential, which exhibits the role of the pairing fluctuations in a more explicit manner.
UR - http://www.scopus.com/inward/record.url?scp=33947516624&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33947516624&partnerID=8YFLogxK
U2 - 10.1103/PhysRevA.75.033609
DO - 10.1103/PhysRevA.75.033609
M3 - Article
AN - SCOPUS:33947516624
VL - 75
JO - Physical Review A
JF - Physical Review A
SN - 2469-9926
IS - 3
M1 - 033609
ER -