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

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 » 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.« less

Authors:
 [1];  [1]
  1. Department of Physics, University of Toronto, Toronto, Ontario, M5S 1A7 (Canada)
Publication Date:
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.
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
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.
@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}
}