Superfluid transition temperature in a trapped gas of Fermi atoms with a Feshbach resonance

doi:https://doi.org/10.1103/PhysRevA.67.033603

Title: Superfluid transition temperature in a trapped gas of Fermi atoms with a Feshbach resonance

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Abstract

We investigate strong-coupling effects on the superfluid phase transition in a gas of Fermi atoms with a Feshbach resonance. The Feshbach resonance describes a composite quasiboson that can give rise to an additional pairing interaction between the Fermi atoms. This attractive interaction becomes stronger as the threshold energy 2{nu} of the Feshbach resonance two-particle bound state is lowered. In a recent paper, we showed that in the uniform Fermi gas, this tunable pairing interaction naturally leads to a crossover from a BCS state to a Bose-Einstein condensate (BEC) of the Nozieres and Schmitt-Rink kind, in which the BCS-type superfluid phase transition continuously changes into the BEC type as the threshold energy is decreased. In this paper, we extend our previous work by including the effect of a harmonic trap potential, treated within the local-density approximation. We also give results for both weak and strong coupling to the Feshbach resonance. We show that the BCS-BEC crossover phenomenon strongly modifies the shape of the atomic density profile at the superfluid phase-transition temperature T{sub c}, reflecting the change of the dominant particles going from Fermi atoms to composite bosons. In the BEC regime, these composite bosons are shown to first appear well abovemore »« less

Authors:

Ohashi, Y ^[1]; Griffin, A ^[1]

Department of Physics, University of Toronto, Toronto, Ontario, M5S 1A7 (Canada)

Publication Date:: 2003-03-01

OSTI Identifier:: 20633868

Resource Type:: Journal Article

Journal Name:: Physical Review. A

Additional Journal Information:: Journal Volume: 67; Journal Issue: 3; Other Information: DOI: 10.1103/PhysRevA.67.033603; (c) 2003 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1050-2947

Country of Publication:: United States

Language:: English

Subject:: 74 ATOMIC AND MOLECULAR PHYSICS; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ATOMS; BINDING ENERGY; BOSE-EINSTEIN CONDENSATION; BOSONS; BOUND STATE; DENSITY; FERMI GAS; FLUCTUATIONS; MOLECULES; PAIRING INTERACTIONS; PHASE DIAGRAMS; PHASE TRANSFORMATIONS; POTENTIALS; RESONANCE; SUPERFLUIDITY; THRESHOLD ENERGY; TRANSITION TEMPERATURE; TRAPPING; TRAPS

Citation Formats


                    Ohashi, Y, Institute of Physics, University of Tsukuba, Ibaraki 305, and Griffin, A. Superfluid transition temperature in a trapped gas of Fermi atoms with a Feshbach resonance.  United States: N. p., 2003. 
        Web.  doi:10.1103/PhysRevA.67.033603.

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                    Ohashi, Y, Institute of Physics, University of Tsukuba, Ibaraki 305, & Griffin, A. Superfluid transition temperature in a trapped gas of Fermi atoms with a Feshbach resonance.  United States.  https://doi.org/10.1103/PhysRevA.67.033603

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                    Ohashi, Y, Institute of Physics, University of Tsukuba, Ibaraki 305, and Griffin, A. Sat .  
        "Superfluid transition temperature in a trapped gas of Fermi atoms with a Feshbach resonance".  United States.  https://doi.org/10.1103/PhysRevA.67.033603.

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@article{osti_20633868,

  title        = {Superfluid transition temperature in a trapped gas of Fermi atoms with a Feshbach resonance},

  author       = {Ohashi, Y and Institute of Physics, University of Tsukuba, Ibaraki 305 and Griffin, A},

  abstractNote = {We investigate strong-coupling effects on the superfluid phase transition in a gas of Fermi atoms with a Feshbach resonance. The Feshbach resonance describes a composite quasiboson that can give rise to an additional pairing interaction between the Fermi atoms. This attractive interaction becomes stronger as the threshold energy 2{nu} of the Feshbach resonance two-particle bound state is lowered. In a recent paper, we showed that in the uniform Fermi gas, this tunable pairing interaction naturally leads to a crossover from a BCS state to a Bose-Einstein condensate (BEC) of the Nozieres and Schmitt-Rink kind, in which the BCS-type superfluid phase transition continuously changes into the BEC type as the threshold energy is decreased. In this paper, we extend our previous work by including the effect of a harmonic trap potential, treated within the local-density approximation. We also give results for both weak and strong coupling to the Feshbach resonance. We show that the BCS-BEC crossover phenomenon strongly modifies the shape of the atomic density profile at the superfluid phase-transition temperature T{sub c}, reflecting the change of the dominant particles going from Fermi atoms to composite bosons. In the BEC regime, these composite bosons are shown to first appear well above T{sub c}. We also discuss the 'phase diagram' above T{sub c} as a function of the tunable threshold energy 2{nu}. We introduce a characteristic temperature T*(2{nu}) describing the effective crossover in the normal phase from a Fermi gas of atoms to a gas of stable molecules.},

  doi          = {10.1103/PhysRevA.67.033603},

  url          = {https://www.osti.gov/biblio/20633868},
  journal      = {Physical Review. A},

  issn         = {1050-2947},

  number       = 3,

  volume       = 67,

  place        = {United States},

  year         = {2003},

  month        = {3}

}

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