BCS to Bose crossover: Broken-symmetry state

Engelbrecht, Jan R.; Randeria, Mohit; Melo, C. A. R. Sá de

doi:10.1103/physrevb.55.15153

Cited by 416 publications

(587 citation statements)

References 12 publications

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“…14. The zero point motion is largely influenced by the presence of the Bogoliubov spectrum of the diquark zero mode, discussed in Appendix B [8,37,41,48]. The pressure curves in Fig.…”

Section: Equation Of State Of Quark-hadron Mattermentioning

confidence: 99%

Quark–hadron matter at finite temperature and density in a two-color PNJL model

2013

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Quark-hadron matter at finite temperature and density is studied using a two-flavor, color SU(2) (P)NJL model. The hadronic effective Lagrangian, derived by bosonization of the quark fields and renormalized using the Eguchi method, emerges in the form of an extended linear σ model with meson and diquark-baryon fields. Chiral and diquark condensates are studied as functions of temperature and baryon density. Masses of mesons and diquarkbaryons are calculated with and without the Polyakov loop effect. We investigate the equation of state of quark-hadron matter by taking into account the contributions of mesons and diquark-baryons in addition to the quark quasiparticles.

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“…14. The zero point motion is largely influenced by the presence of the Bogoliubov spectrum of the diquark zero mode, discussed in Appendix B [8,37,41,48]. The pressure curves in Fig.…”

Section: Equation Of State Of Quark-hadron Mattermentioning

confidence: 99%

Quark–hadron matter at finite temperature and density in a two-color PNJL model

2013

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“…Statements about binding energies of the pairs χ x,↑ (t p ) χ x,↓ (t p ) can be calculated by various saddle point considerations from the coherent state path integral (24) [25,26]. However, the exact expression of the saddle point is not needed for the derivation of the nonlinear sigma model with actions (54) and (55) for the time development of a condensate composed of fermionic atoms.…”

Section: Summary and Discussionmentioning

confidence: 99%

Nonlinear sigma model for a condensate composed of fermionic atoms

Mieck

2005

Physica A: Statistical Mechanics and its Applications

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A nonlinear sigma model is derived for the time development of a Bose-Einstein condensate composed of fermionic atoms. Spontaneous symmetry breaking of a Sp(2) symmetry in a coherent state path integral with anticommuting fields yields Goldstone bosons in a Sp(2)\U (2) coset space. After a Hubbard-Stratonovich transformation from the anticommuting fields to a local self-energy matrix with anomalous terms, the assumed short-ranged attractive interaction reduces this symmetry to a SO(4)\U (2) coset space with only one complex Goldstone field for the singlett pairs of fermions. This bosonic field for the anomalous term of fermions is separated in a gradient expansion from the density terms. The U (2) invariant density terms are considered as a background field or unchanged interacting Fermi sea in the spontaneous symmetry breaking of the SO(4) invariant action and appear as coefficients of correlation functions in the nonlinear sigma model for the Goldstone boson. The time development of the condensate composed of fermionic atoms results in a modified Sine-Gordon equation.

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“…[5], we can straightforwardly infer that in the BEC limit ξ/k −1 ∆ ∝ |κ| 1/4 . It follows that ξ/k −1 ∆ → ∞ in the BEC limit, which seems to suggest that this limit is out of the application scope of our theory, since the latter is intrinsically valid for physics at distances longer than ξ.…”

Section: Experimental Parameters and Conditionsmentioning

confidence: 99%

“…Vortices have been studied for decades, experimentally and/or theoretically, in a variety of systems as diverse as type-II superconductors, superfluid Helium liquids, rotating ultracold atomic Bose and Fermi gases, and neutron stars. [1] Among these systems, the quantum gas of resonantly interacting fermionic atoms with equal populations of both (hyperfine) spin components, a prototype system for the interesting BEC-BCS crossover physics, [2,3,4,5,6] has been intensively studied over the past several years. The first experimental observation of vortices in 2005 by the MIT group provided a definitive evidence for superfluidity in atomic Fermi gases.…”

Section: Introductionmentioning

confidence: 99%

Unconventional interaction between vortices in a polarized Fermi gas

2008

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Recently, a homogeneous superfluid state with a single gapless Fermi surface was predicted to be the ground state of an ultracold Fermi gas with spin population imbalance in the regime of molecular Bose-Einstein condensation. We study vortices in this novel state using a symmetry-based effective field theory, which captures the low-energy physics of gapless fermions and superfluid phase fluctuations. This theory is applicable to all spin-imbalanced ultracold Fermi gases in the superfluid regime, regardless of whether the original fermion pairing interaction is weak or strong. We find a remarkable, unconventional form of the interaction between vortices. The presence of gapless fermions gives rise to a spatially oscillating potential, akin to the RKKY indirect-exchange interaction in non-magnetic metals. We compare the parameters of the effective theory to the experimentally measurable quantities and further discuss the conditions for the verification of the predicted new feature. Our study opens up an interesting question as to the nature of the vortex lattice resulting from the competition between the usual repulsive logarithmic (2D Coulomb) and predominantly attractive fermion-induced interactions.

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BCS to Bose crossover: Broken-symmetry state

Cited by 416 publications

References 12 publications

Quark–hadron matter at finite temperature and density in a two-color PNJL model

Quark–hadron matter at finite temperature and density in a two-color PNJL model

Nonlinear sigma model for a condensate composed of fermionic atoms

Unconventional interaction between vortices in a polarized Fermi gas

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