Spin susceptibility and strong coupling effects in an ultracold Fermi gas

H. Tajima, R. Hanai, R. Watanabe, Y. Ohashi

Research output: Contribution to journalArticle

Abstract

We investigate magnetic properties and strong coupling corrections in the BCS (Bardeen-Cooper-Schrieffer)-BEC (Bose-Einstein condensation) crossover regime of an ultracold Fermi gas. Within the framework of an extended T-matrix theory, we calculate the spin susceptibility χ above the superfluid phase transition temperature Tc. In the crossover region, the formation of preformed Cooper pairs is shown to cause a non-monotonic temperature dependence of χ, which is similar to the so-called spin-gap phenomenon observed in the under-doped regime of high-T c cuprates. From this behavior of χ, we determine the spin-gap temperature as the temperature at which χ takes a maximum value, in the BCS-BEC crossover region. Since the spin susceptibility is sensitive to the formation of singlet Cooper pairs, our results would be useful in considering the temperature region where pairing fluctuations are important in the BCS-BEC crossover regime of an ultracold Fermi gas.

Original languageEnglish
Pages (from-to)279-286
Number of pages8
JournalJournal of Low Temperature Physics
Volume175
Issue number1-2
DOIs
Publication statusPublished - 2014 Apr

Keywords

  • BCS-BEC crossover
  • Fermi superfluid
  • Spin-gap phenomenon

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Materials Science(all)
  • Condensed Matter Physics

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