The self-trapping of superfluid Fermi gases in the Bose-Einstein condensation regime and in unitarity

We discuss the superfluid phase transition in a gas of Fermi atoms with a Feshbach resonance. A tunable pairing interaction associated with the Feshbach resonance is shown to naturally lead to the BCS-BEC crossover, where the character of superfluidity continuously changes from the weak-coupling Bardeen-Cooper-Schrieffer (BCS) type to the Bose-Einstein condensation (BEC) of tightly bound molecules, as one decreases the threshold energy 2ν of the Feshbach resonance. We also discuss effects of a trap, as well as the p-wave BCS-BEC crossover adjusted by a p-wave Feshbach resonance.

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Effect of the particle-hole channel on BCS–Bose-Einstein condensation crossover in atomic Fermi gases

Scientific Reports ◽

10.1038/srep25772 ◽

2016 ◽

Vol 6 (1) ◽

Cited By ~ 5

Author(s):

Qijin Chen

Keyword(s):

Fermi Gases ◽

Einstein Condensation ◽

Bose Einstein Condensation ◽

Bose Einstein

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SUPERFLUID REGIMES IN DEGENERATE ATOMIC FERMI GASES

International Journal of Modern Physics B ◽

10.1142/s0217979206035242 ◽

2006 ◽

Vol 20 (19) ◽

pp. 2739-2754

Author(s):

G. V. SHLYAPNIKOV

Keyword(s):

Scattering Length ◽

Fermi Gases ◽

Einstein Condensation ◽

Weakly Bound ◽

Future Studies ◽

Bose Einstein Condensation ◽

Ultracold Fermi Gases ◽

Fermionic Atoms ◽

Atom Interaction ◽

Bose Einstein

We give a brief overview of recent studies of quantum degenerate regimes in ultracold Fermi gases. The attention is focused on the regime of Bose-Einstein condensation of weakly bound molecules of fermionic atoms, formed at a large positive scattering length for the interspecies atom-atom interaction. We analyze remarkable collisional stability of these molecules and draw prospects for future studies.

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Is FeSe a superconductor in the Bose-Einstein condensation limit?

10.36471/jccm_november_2017_01 ◽

2017 ◽

Keyword(s):

Einstein Condensation ◽

Bose Einstein Condensation ◽

Bose Einstein

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Systems with Condensates and Pairing

10.1093/oso/9780198797241.003.0012 ◽

2018 ◽

Author(s):

Klaus Morawetz

Keyword(s):

Critical Parameters ◽

Einstein Condensation ◽

Cooper Pairs ◽

Pair Breaking ◽

Systematic Theory ◽

Bose Einstein Condensation ◽

T Matrix ◽

The Stability ◽

Bose Einstein

The Bose–Einstein condensation and appearance of superfluidity and superconductivity are introduced from basic phenomena. A systematic theory based on the asymmetric expansion of chapter 11 is shown to correct the T-matrix from unphysical multiple-scattering events. The resulting generalised Soven scheme provides the Beliaev equations for Boson’s and the Nambu–Gorkov equations for fermions without the usage of anomalous and non-conserving propagators. This systematic theory allows calculating the fluctuations above and below the critical parameters. Gap equations and Bogoliubov–DeGennes equations are derived from this theory. Interacting Bose systems with finite temperatures are discussed with successively better approximations ranging from Bogoliubov and Popov up to corrected T-matrices. For superconductivity, the asymmetric theory leading to the corrected T-matrix allows for establishing the stability of the condensate and decides correctly about the pair-breaking mechanisms in contrast to conventional approaches. The relation between the correlated density from nonlocal kinetic theory and the density of Cooper pairs is shown.

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