Shear viscosity and strong-coupling corrections in the BCS–BEC crossover regime of an ultracold Fermi gas

Daichi Kagamihara, Daisuke Inotani, Yoji Ohashi

Research output: Contribution to journalArticle

Abstract

We theoretically investigate the shear viscosity η in the BCS–BEC crossover regime of an ultracold Fermi gas with a Feshbach resonance. Within the framework of the strong-coupling self-consistent T-matrix approximation, we examine how a strong pairing interaction associated with a Feshbach resonance affects this transport coefficient, in the normal state above the superfluid phase transition temperature Tc. We show that, while η diverges in both the weak-coupling BCS and strong-coupling BEC limits, it becomes small in the unitary regime. The minimum of η is obtained, not at the unitarity, but slightly in the strong-coupling BEC side. This deviation is consistent with the recent experiment on a 6Li Fermi gas. In the weak-coupling BCS regime, we also find that η exhibits anomalous temperature dependence near Tc, which is deeply related to the pseudogap phenomenon originating from strong pairing fluctuations.

Original languageEnglish
Article number114001
JournalJournal of the Physical Society of Japan
Volume88
Issue number11
DOIs
Publication statusPublished - 2019 Jan 1

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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