Spin Susceptibility and Effects of Inhomogeneous Strong Pairing Fluctuations in a Trapped Ultracold Fermi Gas

H. Tajima, R. Hanai, Yoji Ohashi

Research output: Contribution to journalArticle

Abstract

We theoretically investigate magnetic properties of a unitary Fermi gas in a harmonic trap. Including strong pairing fluctuations within the framework of an extended T-matrix approximation, as well as effects of a trap potential within the local density approximation, we calculate the local spin susceptibility (Formula presented.) above the superfluid phase transition temperature (Formula presented.). We show that the formation of preformed singlet Cooper pairs anomalously suppresses (Formula presented.) in the trap center near (Formula presented.). We also point out that, in the unitarity limit, the spin-gap temperature in a uniform Fermi gas can be evaluated from the observation of the spatial variation of (Formula presented.). Since a real ultracold Fermi gas is always in a trap potential, our results would be useful for the study of how this spatial inhomogeneity affects thermodynamic properties of an ultracold Fermi gas in the BCS–BEC crossover region.

Original languageEnglish
Pages (from-to)1-8
Number of pages8
JournalJournal of Low Temperature Physics
DOIs
Publication statusAccepted/In press - 2015 Dec 7

Fingerprint

Gases
magnetic permeability
traps
gases
Local density approximation
Superconducting transition temperature
Magnetic properties
approximation
Thermodynamic properties
Phase transitions
crossovers
inhomogeneity
thermodynamic properties
transition temperature
magnetic properties
harmonics
Temperature
temperature

Keywords

  • BCS–BEC crossover
  • Fermi superfluid
  • Spin gap
  • Strong-coupling effects

ASJC Scopus subject areas

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

Cite this

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abstract = "We theoretically investigate magnetic properties of a unitary Fermi gas in a harmonic trap. Including strong pairing fluctuations within the framework of an extended T-matrix approximation, as well as effects of a trap potential within the local density approximation, we calculate the local spin susceptibility (Formula presented.) above the superfluid phase transition temperature (Formula presented.). We show that the formation of preformed singlet Cooper pairs anomalously suppresses (Formula presented.) in the trap center near (Formula presented.). We also point out that, in the unitarity limit, the spin-gap temperature in a uniform Fermi gas can be evaluated from the observation of the spatial variation of (Formula presented.). Since a real ultracold Fermi gas is always in a trap potential, our results would be useful for the study of how this spatial inhomogeneity affects thermodynamic properties of an ultracold Fermi gas in the BCS–BEC crossover region.",
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AU - Hanai, R.

AU - Ohashi, Yoji

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N2 - We theoretically investigate magnetic properties of a unitary Fermi gas in a harmonic trap. Including strong pairing fluctuations within the framework of an extended T-matrix approximation, as well as effects of a trap potential within the local density approximation, we calculate the local spin susceptibility (Formula presented.) above the superfluid phase transition temperature (Formula presented.). We show that the formation of preformed singlet Cooper pairs anomalously suppresses (Formula presented.) in the trap center near (Formula presented.). We also point out that, in the unitarity limit, the spin-gap temperature in a uniform Fermi gas can be evaluated from the observation of the spatial variation of (Formula presented.). Since a real ultracold Fermi gas is always in a trap potential, our results would be useful for the study of how this spatial inhomogeneity affects thermodynamic properties of an ultracold Fermi gas in the BCS–BEC crossover region.

AB - We theoretically investigate magnetic properties of a unitary Fermi gas in a harmonic trap. Including strong pairing fluctuations within the framework of an extended T-matrix approximation, as well as effects of a trap potential within the local density approximation, we calculate the local spin susceptibility (Formula presented.) above the superfluid phase transition temperature (Formula presented.). We show that the formation of preformed singlet Cooper pairs anomalously suppresses (Formula presented.) in the trap center near (Formula presented.). We also point out that, in the unitarity limit, the spin-gap temperature in a uniform Fermi gas can be evaluated from the observation of the spatial variation of (Formula presented.). Since a real ultracold Fermi gas is always in a trap potential, our results would be useful for the study of how this spatial inhomogeneity affects thermodynamic properties of an ultracold Fermi gas in the BCS–BEC crossover region.

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