Higgs instability in gapless superfluidity/superconductivity

Giannakis, Ioannis; Hou, Defu; Huang, Mei; Ren, Hai-cang

doi:10.1103/physrevd.75.011501

Cited by 20 publications

(30 citation statements)

References 48 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…To do this in the NJL model, additional chemical potentials related to the electric charge density of quarks and electrons as well as to color charges must be introduced. Recently, an intensive theoretical study of neutral color superconducting quark matter has been given (see, e. g., [16,17,18,19,20,21,22,23,24,25,26]), which revealed a new possible ground state of the 2SC phase, where some additional number of quasiparticles with a gapless dispersion law is appeared [19] (it is the so-called gapless color superconductivity g2SC, an antipode to the usual, gapped 2SC).…”

Section: Introductionmentioning

confidence: 99%

Mesons and diquarks in neutral color superconducting quark matter withβequilibrium

2007

View full text Add to dashboard Cite

The spectrum of meson and diquark excitations in cold color-superconducting (2SC) quark matter is investigated under local color and electric neutrality constraints with β-equilibrium. A 2-flavored Nambu-Jona-Lasinio type model including a baryon µB, color µ8, and electric µQ chemical potentials is used. The contribution from free electrons to the free energy is added to take into account the β-equilibrium. The sensitivity of the model to the tuning of the interaction constants in the diquark (H) and quark-antiquark (G) channels is examined for two different parameterization schemes by choosing the ratio H/G to be 3/4 and 1, respectively. At H = 3G/4 the gapless-and at H = G the gapped neutral color superconductivity is realized. It is shown that color and electrical neutrality together with β-equilibrium lead to a strong mass splitting within the pion isotriplet in the 2SC phase (both gapped and gapless), in contrast with non-neutral matter. The π-and σ-meson masses are evaluated to be ∼ 300 MeV. It is also shown that the properties of the physical SU (2)c-singlet diquark excitation in the 2SC ground state varies for different parameterization schemes. Thus, for H = 3G/4 one finds a heavy resonance with mass ∼ 1100 MeV in the non-neutral (gapped) case, whereas, if neutrality is imposed, a stable diquark with mass ∼ |µQ| ∼ 200 MeV appears in the gapless 2SC environment. For a stronger attraction in the diquark channel (H = G), there is again a resonance (with the mass ∼ 300 MeV) in the neutral gapped 2SC phase. Hence, the existence of the stable massive SU(2)c-singlet diquark excitation is a new peculiarity of the gapless 2SC. In addition, the behaviour of the diquark mass in vacuum, i. e. , at µB = 0, as a function of H has been investigated.

show abstract

Section: Introductionmentioning

confidence: 99%

Mesons and diquarks in neutral color superconducting quark matter withβequilibrium

2007

View full text Add to dashboard Cite

show abstract

“…(47) and (48). The Higgs self-energy function (46) goes to the expression derived from the GinzburgLandau theory [34]. The Ginzburg-Landau free energy for g2SC can be easily obtained from that of an electronic superconductor by replacing the Fermi momentum k F withμ, the Fermi velocity with one and multiplying the whole expression by four (four pairing configurations per momentum for g2SC versus one for the electronic SC).…”

Section: Higgs Instabilitymentioning

confidence: 99%

“…(In the case of homogeneous superconducting phase, k min = 0, and l → ∞.) Considering that the coherence length ξ of a superconductor is proportianl to the inverse of the gap magnitude, i.e., ξ ≃ ∆ −1 [34], therefore, a rather large ratio of k min /∆ means a rather small ratio of l/ξ. When l/ξ < 1, a phase separation state is more favorable [38].…”

Section: Nonzero Momentum Casementioning

confidence: 99%

“…In Refs. [28] and [29], a new type of instability, Higgs instability, was discovered. The Higgs instability, being an instability with respect to an inhomogeneous fluctuation of the gap magnitude, may favor non-uniform mixed state or LO state more than the single-plane wave FF state or Nambu-Goldstone current state.…”

Section: Introductionmentioning

confidence: 99%

“…We try the first step toward this direction by exploring the Higgs instability of a homogeneous 2SC. The Higgs instability is a straightforward extension of the Sarma instability but has not received much attention until recently [28,29]. The Higgs instability refers to the instability of a homogeneous CSC state against an inhomogeneous fluctuation of the magnitude of the gap parameter, which is not protected by globally imposed constraints, its salient features have been discussed in the short letter [29].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Inhomogeneity driven by Higgs instability in a gapless superconductor

et al. 2007

Self Cite

View full text Add to dashboard Cite

The fluctuations of the Higgs and pseudo Nambu-Goldstone fields in the 2SC phase with mismatched pairing are described in the nonlinear realization framework of the gauged Nambu-JonaLasinio model. In the gapless 2SC phase, not only Nambu-Goldstone currents can be spontaneously generated, but the Higgs field also exhibits instablity. The Nambu-Goldstone currents generation indicates the formation of the single plane wave LOFF state and breaks rotation symmetry, while the Higgs instability favors spatial inhomogeneity and breaks translation invariance. In this paper, we focus on the Higgs instability which has not drawn much attention yet. The Higgs instability cannot be removed without a long range force, thus it persists in the gapless superfluidity and induces phase separation. In the case of g2SC state, the Higgs instability can only be partially removed by the electric Coulomb energy. However, it is not excluded that the Higgs instability might be completely removed in the charge neutral gCFL phase by the color Coulomb energy.

show abstract

Collective modes in asymmetric ultracold Fermi systems

2010

View full text Add to dashboard Cite

We derive the low energy effective action for the collective modes in systems of fermions interacting via a short-range s-wave attraction, featuring unequal chemical potentials for the two fermionic species (asymmetric systems). As a consequence of the attractive interaction, fermions form a condensate that spontaneously breaks the U(1) symmetry associated with total number conservation. Therefore at sufficiently small temperatures and asymmetries, the system is a superfluid. We reproduce previous results for the stability conditions of the system as a function of the four-fermion coupling and asymmetry. We obtain these results analyzing the coefficients of the low energy effective Lagrangian of the modes describing fluctuations in the magnitude (Higgs mode) and in the phase (Goldstone mode) of the difermion condensate. We find that for certain values of parameters, the mass of the Higgs mode decreases with increasing mismatch between the chemical potentials of the two populations, if we keep the scattering length and the gap parameter constant. Furthermore, we find that the energy cost for creating a position dependent fluctuation of the condensate is constant in the gapped region and increases in the gapless region. These two features may lead to experimentally detectable effects. As an example, we argue that if the superfluid is put in rotation, the square of the radius of the outer core of a vortex should sharply increase on increasing the asymmetry, when we pass through the relevant region in the gapless superfluid phase. Finally, by gauging the global U(1) symmetry, we relate the coefficients of the effective Lagrangian of the Goldstone mode with the screening masses of the gauge field.Comment: 41 pages, 6 figures. Expanded introduction, improved figures, conclusions unchanged. Version to match the published versio

show abstract

Higgs instability in gapless superfluidity/superconductivity

Cited by 20 publications

References 48 publications

Mesons and diquarks in neutral color superconducting quark matter withβequilibrium

Mesons and diquarks in neutral color superconducting quark matter withβequilibrium

Inhomogeneity driven by Higgs instability in a gapless superconductor

Collective modes in asymmetric ultracold Fermi systems

Contact Info

Product

Resources

About