On the influence of a uniform exchange field acting on the spins of the conduction electrons in a superconductor

Sarma, G.

doi:10.1016/0022-3697(63)90007-6

Cited by 626 publications

(639 citation statements)

References 5 publications

Supporting

Mentioning

596

Contrasting

Order By: Relevance

“…In the most of the literature concerning the pairing phases of the quark matter [11,23,25], the strange quark mass is treated as a parameter just like an external magnetic field applied to a metallic superconductor [26]. In QCD, however, the strong attraction exists in the scaler quark-antiquark channel which leads to a non-perturbative phenomenon called the dynamical chiral condensation in the low density regime.…”

Section: Introductionmentioning

confidence: 99%

Extensive study of phase diagram for charge-neutral homogeneous quark matter affected by dynamical chiral condensation: unified picture for thermal unpairing transitions from weak to strong coupling

2006

View full text Add to dashboard Cite

We study the phase structures of charge neutral quark matter under the β-equilibrium for a wide range of the quark-quark coupling strength within a four-Fermion model. A comprehensive and unified picture for the phase transitions from weak to strong coupling is presented. We first develop a technique to deal with the gap equation and neutrality constraints without recourse to numerical derivatives, and show that the off-diagonal color densities automatically vanish with the standard assumption for the diquark condensates. The following are shown by the numerical analyses: (i) The thermally-robustest pairing phase is the two-flavor pairing (2SC) in any coupling case, while the second one for relatively low density is the up-quark pairing (uSC) phase or the color-flavor locked (CFL) phase depending on the coupling strength and the value of strange quark mass. (ii) If the diquark coupling strength is large enough, the phase diagram is much simplified and is free from the instability problems associated with imaginary Meissner masses in the gapless phases. (iii) The interplay between the chiral and diquark dynamics may bring a non-trivial first order transition even in the pairing phases at high density. We confirm (i) also by using the Ginzburg-Landau analysis expanding the pair susceptibilities up to quartic order in the strange quark mass. We obtain the analytic expression for the doubly critical density where the two lines for the second order phase transitions merge, and below which the down-quark pairing (dSC) phase is taken over by the uSC phase. Also we study how the phase transitions from fully gapped states to partially ungapped states are smeared at finite temperature by introducing the order parameters for these transitions.

show abstract

Section: Introductionmentioning

confidence: 99%

Extensive study of phase diagram for charge-neutral homogeneous quark matter affected by dynamical chiral condensation: unified picture for thermal unpairing transitions from weak to strong coupling

2006

View full text Add to dashboard Cite

show abstract

“…In past ten years, these exotic superfluid phases have been extensively studied, both theoretically [1,2,3,4,5] and experimentally [6,7,8,9,10,11] in ultra-cold atomic gases and in quark-gluon plasma which resides in the core of neutron stars [12,13]. Similar imbalanced fermionic systems were studied in electron superconductors in a magnetic field as early as nineteen-sixties [14,15], and showed the possibility of tricritical points where the second-order and the first-order lines meet along with the line separating stable and unstable superconducting phases. That the tricritical point is fundamental to the understanding of superfluidity of polarized, two-component Fermi gases was first pointed out by Parish et al [16].…”

Section: Introductionmentioning

confidence: 99%

Competing order parameters and a tricritical point with a difference

Dutta

Bhattacharjee

2012

Physica B: Condensed Matter

View full text Add to dashboard Cite

We propose a mean-field, phenomenological Ginzburg-Landau free energy functional with two competing order parameters for a two-component, spin-polarized Fermi gas. This free energy supports a tricritical point which is different from the conventional one and this change offers a correct understanding of the experimental phase diagram of imbalanced Fermi systems ( Shin et al, Nature, 2008). The specific heat also happens to be different than in standard theory.

show abstract

“…The theoretical interest in pairing with mismatched Fermi surfaces has been revitalized by the proposal of breachedpairing superfluidity, with a number of exotic superfluid states being proposed or revisited. [13,14] Breached-pairing superfluid phase with two gapless Fermi surfaces (BP2), related to the unstable Sarma phase, [15] was found to be stable under the introduction of new effects, such as the mass imbalance and/or momentum-dependent pairing interaction. [16,17] Important developments in the subject are recent studies by various groups [18,19,20] investigating the Feshbach-resonant regime of strong interactions.…”

Section: Introductionmentioning

confidence: 99%

Unconventional interaction between vortices in a polarized Fermi gas

2008

View full text Add to dashboard Cite

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.

show abstract

On the influence of a uniform exchange field acting on the spins of the conduction electrons in a superconductor

Cited by 626 publications

References 5 publications

Extensive study of phase diagram for charge-neutral homogeneous quark matter affected by dynamical chiral condensation: unified picture for thermal unpairing transitions from weak to strong coupling

Extensive study of phase diagram for charge-neutral homogeneous quark matter affected by dynamical chiral condensation: unified picture for thermal unpairing transitions from weak to strong coupling

Competing order parameters and a tricritical point with a difference

Unconventional interaction between vortices in a polarized Fermi gas

Contact Info

Product

Resources

About