We consider the superfluid phase transition that arises when a Feshbach resonance pairing occurs in a dilute Fermi gas. We apply our theory to consider a specific resonance in potassium ((40)K), and find that for achievable experimental conditions, the transition to a superfluid phase is possible at the high critical temperature of about 0.5T(F). Observation of superfluidity in this regime would provide the opportunity to experimentally study the crossover from the superfluid phase of weakly coupled fermions to the Bose-Einstein condensation of strongly bound composite bosons.We consider the superfluid phase transition that arises when a Feshbach resonance pairing occurs in a dilute Fermi gas. We apply our theory to consider a specific resonance in potassium ((40)K), and find that for achievable experimental conditions, the transition to a superfluid phase is possible at the high critical temperature of about 0.5T(F). Observation of superfluidity in this regime would provide the opportunity to experimentally study the crossover from the superfluid phase of weakly coupled fermions to the Bose-Einstein condensation of strongly bound composite bosons.

arXiv:cond-mat/0103479Physical Review LettersAug 31, 2001506 citations

Phase transitions in ideal Bose gases

B. Ya. Balagurov, Валентин Григорьевич Вакс

Jan 1, 19750 citations

SUPERFLUIDITY AND A NON-IDEAL BOSE GAS

WORLD SCIENTIFIC eBooksDec 1, 20090 citations

Finite-momentum superfluidity and phase transitions in a p -wave resonant Bose gas

Sungsoo Choi, Leo Radzihovsky

We study a degenerate two-species gas of bosonic atoms interacting through a $p$ -wave Feshbach resonance as, for example, realized in a ${}^{85}$ Rb- ${}^{87}$ Rb mixture. We show that, in addition to a conventional atomic and a $p$ -wave molecular spinor-1 superfluidity at large positive and negative detunings, respectively, the system generically exhibits a finite-momentum atomic-molecular superfluidity at intermediate detuning around the unitary point. We analyze the detailed nature of the corresponding phases and the associated quantum and thermal phase transitions.We study a degenerate two-species gas of bosonic atoms interacting through a $p$-wave Feshbach resonance as, for example, realized in a ${}^{85}$Rb-${}^{87}$Rb mixture. We show that, in addition to a conventional atomic and a $p$-wave molecular spinor-1 superfluidity at large positive and negative detunings, respectively, the system generically exhibits a finite-momentum atomic-molecular superfluidity at intermediate detuning around the unitary point. We analyze the detailed nature of the corresponding phases and the associated quantum and thermal phase transitions.

arXiv:1106.5765Physical Review AOct 10, 201113 citations

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

Yutaro OHASHI, Adam Griffin

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 $2\ensuremath{\nu}$ 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 Nozi\`eres 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 ${T}_{\mathrm{c}},$ 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 ${T}_{\mathrm{c}}.$ We also discuss the ``phase diagram'' above ${T}_{\mathrm{c}}$ as a function of the tunable threshold energy $2\ensuremath{\nu}.$ We introduce a characteristic temperature ${T}^{*}(2\ensuremath{\nu})$ describing the effective crossover in the normal phase from a Fermi gas of atoms to a gas of stable molecules.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 $2\ensuremath{\nu}$ 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 Nozi\`eres 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 ${T}_{\mathrm{c}},$ 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 ${T}_{\mathrm{c}}.$ We also discuss the ``phase diagram'' above ${T}_{\mathrm{c}}$ as a function of the tunable threshold energy $2\ensuremath{\nu}.$ We introduce a characteristic temperature ${T}^{*}(2\ensuremath{\nu})$ describing the effective crossover in the normal phase from a Fermi gas of atoms to a gas of stable molecules.

arXiv:cond-mat/0210185Physical Review AMar 14, 2003108 citations

PHASE TRANSITIONS IN ULTRA-COLD TWO-DIMENSIONAL BOSE GASES

David A. W. Hutchinson, P. B. Blakie

Recent Progress in Many-Body TheoriesSep 1, 20060 citations

We study a degenerate two-species gas of bosonic atoms interacting through a

p

-wave Feshbach resonance as, for example, realized in a

{}^{85}

Rb-

{}^{87}

Rb mixture. We show that, in addition to a conventional atomic and a

p

-wave molecular spinor-1 superfluidity at large positive and negative detunings, respectively, the system generically exhibits a finite-momentum atomic-molecular superfluidity at intermediate detuning around the unitary point. We analyze the detailed nature of the corresponding phases and the associated quantum and thermal phase transitions.

{T}_{\mathrm{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}_{\mathrm{c}}.

We also discuss the ``phase diagram'' above

{T}_{\mathrm{c}}

as a function of the tunable threshold energy $2\ensuremath{\nu}.$ We introduce a characteristic temperature ${T}^{*}(2\ensuremath{\nu})$ describing the effective crossover in the normal phase from a Fermi gas of atoms to a gas of stable molecules.