Strong-Coupling Effects and Shear Viscosity in an Ultracold Fermi Gas

D. Kagamihara, Y. Ohashi

研究成果: Article査読

2 被引用数 (Scopus)

抄録

We theoretically investigate the shear viscosity η, as well as the entropy density s, in the normal state of an ultracold Fermi gas. Including pairing fluctuations within the framework of a T-matrix approximation, we calculate these quantities in the Bardeen–Cooper–Schrieffer (BCS)–Bose–Einstein condensation (BEC) crossover region. We also evaluate η/ s, to compare it with the lower bound of this ratio, conjectured by Kovtun, Son, and Starinets (KSS bound). In the weak-coupling BCS side, we show that the shear viscosity η is remarkably suppressed near the superfluid phase transition temperature Tc, due to the so-called pseudogap phenomenon. In the strong-coupling BEC side, we find that, within the neglect of the vertex corrections, one cannot correctly describe η. We also show that η/ s decreases with increasing the interaction strength, to become very close to the KSS bound, ħ/ 4 πkB, on the BEC side.

本文言語English
ページ(範囲)692-698
ページ数7
ジャーナルJournal of Low Temperature Physics
187
5-6
DOI
出版ステータスPublished - 2017 6 1

ASJC Scopus subject areas

  • 原子分子物理学および光学
  • 材料科学(全般)
  • 凝縮系物理学

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