Effective action for superconductors and BCS-Bose crossover

Palo, S. De; Castellani, C.; Castro, C. Di; Chakraverty, B. K.

doi:10.1103/physrevb.60.564

Cited by 81 publications

(128 citation statements)

References 32 publications

(28 reference statements)

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“…In order to introduce the fermionic atom density in the path-integral expressions, a transformation was proposed by De Palo et al [10] based on the identity…”

Section: Expliciting the Fermionic Densitymentioning

confidence: 99%

Path-integral mean-field description of the vortex state in the BEC-to-BCS crossover

2005

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We derive a path-integral description of the vortex state of a fermionic superfluid in the crossover region between the molecular condensate (BEC) regime and the Cooper pairing (BCS) regime.This path-integral formalism, supplemented by a suitable choice for the saddle point value of the pairing field in the presence of a vortex, offers a unified description that encompasses both the BEC and BCS limits. The vortex core size is studied as a function of the tunable interaction strength between the fermionic atoms. We find that in the BEC regime, the core size is determined by the molecular healing length, whereas in the BCS regime, the core size is proportional only to the Fermi wave length. The observation of such quantized vortices in dilute Fermi gases would provide an unambiguous proof of the realization of superfluidity in these gases.

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“…In order to introduce the fermionic atom density in the path-integral expressions, a transformation was proposed by De Palo et al [10] based on the identity…”

Section: Expliciting the Fermionic Densitymentioning

confidence: 99%

Path-integral mean-field description of the vortex state in the BEC-to-BCS crossover

2005

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“…[9] and start from the path integral representation of the partition function for a system consisting of layers of 2D fermions…”

Section: The Effective Actionmentioning

confidence: 99%

Path integral formulation of the tunneling dynamics of a superfluid Fermi gas in an optical potential

2004

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To describe the tunneling dynamics of a stack of two-dimensional fermionic superfluids in an optical potential, we derive an effective action functional from a path integral treatment. This effective action leads, in the saddle point approximation, to equations of motion for the density and the phase of the superfluid Fermi gas in each layer. In the strong coupling limit (where bosonic molecules are formed) these equations reduce to a discrete nonlinear Schrödinger equation, where the molecular tunneling amplitude is reduced for large binding energies. In the weak coupling (BCS) regime, we study the evolution of the stacked superfluids and derive an approximate analytical expression for the Josephson oscillation frequency in an external harmonic potential. Both in the weak and intermediate coupling regimes the detection of the Josephson oscillations described by our path integral treatment constitutes experimental evidence for the fermionic superfluid regime.

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“…Since we are interested in the low-energy regime of S ef f , corrections that go beyond this regime are neglected [15]. Since we are dealing with T = 0 dynamics, the normal component is absent and the superfluid is stiff.…”

Section: The Effective Action and The Hydrodynamic Equations In Amentioning

confidence: 99%

Bogoliubov spectrum of a cigar-shaped Fermi superfluid in an optical lattice at the BEC–BCS crossover

Bhattacherjee

2007

J. Phys. B: At. Mol. Opt. Phys.

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We study the Bogoliubov spectrum of an elongated Fermi superfluid confined in a one-dimensional superfluid along the Bose-Einstein-condensate (BEC)-Bardeen-Cooper-Schrieffer (BCS) crossover. We derive analytic expressions for the effective mass and the Bogoliubov excitation spectrum of the axial quasiparticles along the crossover based on the hydrodynamic theory. Our investigation reveal interesting signatures of BEC-BCS crossover in an optical lattice which deserve experimental investigation.

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Effective action for superconductors and BCS-Bose crossover

Cited by 81 publications

References 32 publications

Path-integral mean-field description of the vortex state in the BEC-to-BCS crossover

Path-integral mean-field description of the vortex state in the BEC-to-BCS crossover

Path integral formulation of the tunneling dynamics of a superfluid Fermi gas in an optical potential

Bogoliubov spectrum of a cigar-shaped Fermi superfluid in an optical lattice at the BEC–BCS crossover

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