Charge neutrality effects on two-flavor color superconductivity

Huang, Mei; Zhuang, Pengfei; Chao, W. Q.

doi:10.1103/physrevd.67.065015

Cited by 126 publications

(143 citation statements)

References 24 publications

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“…Integrating out the quark fields and working in the framework of the Matsubara and Nambu-Gorkov formalism we obtain the following MFA quark thermodynamical potential (a detailed procedure of calculation can be found in Refs. [17][18][19] )…”

Section: The Quark Matter Phasementioning

confidence: 99%

Deconfinement transition in protoneutron stars: Analysis within the Nambu–Jona-Lasinio model

et al. 2010

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We study the effect of color superconductivity and neutrino trapping on the deconfinement transition of hadronic matter into quark matter in a protoneutron star. To describe the strongly interacting matter a two-phase picture is adopted. For the hadronic phase we use different parameterizations of a non-linear Walecka model which includes the whole baryon octet. For the quark matter phase we use an SU (3) f Nambu-Jona-Lasinio effective model which includes color superconductivity. We impose color and flavor conservation during the transition in such a way that just deconfined quark matter is transitorily out of equilibrium with respect to weak interactions. We find that deconfinement is more difficult for small neutrino content and it is easier for lower temperatures although these effects are not too large. In addition they will tend to cancel each other as the protoneutron star cools and deleptonizes, resulting a transition density that is roughly constant along the evolution of the protoneutron star. According to these results the deconfinement transition is favored after substantial cooling and contraction of the protoneutron star.

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Section: The Quark Matter Phasementioning

confidence: 99%

Deconfinement transition in protoneutron stars: Analysis within the Nambu–Jona-Lasinio model

et al. 2010

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“…As a result, one may deal with a thermodynamic potential Ω which depends on two variables ∆, σ or, equivalently, ∆, m ≡ m 0 + σ , only. Then, the expression for the thermodynamic potential Ω can be calculated with the help of (13) (see also, e.g., [11]):…”

Section: Gap Equations and Color Neutrality Conditionmentioning

confidence: 99%

“…Indeed, since the lump of quark matter, which might be created after heavy ion collisions, originated from color neutral objects and is surrounded by a color neutral medium, it is expected to be globally color neutral. To fulfill this requirement, usually the local color neutrality constraint is imposed by introducing several new chemical potentials, µ 3 , µ 8 , etc, into a NJL model [4,10,11]. Otherwise, there will be produced a chromo-electric field resulting in the flow of color charges, so a homogeneous and color conducting quark medium with nonzero color charge densities is not allowed to be a stable one [10].…”

Section: Introductionmentioning

confidence: 99%

Mesons and diquarks in the color neutral superconducting phase of dense cold quark matter

2005

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The spectrum of meson and diquark excitations of dense color neutral cold quark matter is investigated in the framework of a 2-flavored Nambu-Jona-Lasinio type model, including a quark µ-and color µ8 chemical potential. It was found out that in the color superconducting (2SC) phase, i.e. at µ > µc = 342 MeV, µ8 aquires rather small values ∼ 10 MeV in order to ensure the color neutrality. In this phase the π-and σ meson masses are evaluated around ∼ 330 MeV. The spectrum of scalar diquarks in the color neutral 2SC phase consists of a heavy (SUc(2)-singlet) resonance with mass ∼ 1100 MeV, four light diquarks with mass 3|µ8|, and one Nambu -Goldstone boson which is in accordance with the Goldstone theorem. Moreover, in the 2SC phase there are five light stable particles as well as a heavy resonance in the spectrum of pseudo-scalar diquarks. In the color symmetric phase, i.e. for µ < µc, a mass splitting of scalar diquarks and antidiquarks is shown to arise if µ = 0, contrary to the case of µ = 0, where the masses of scalar antidiquarks and diquarks are degenerate at the value ∼ 700 MeV. If the coupling strength in the pseudo-scalar diquark channel is the same as in the scalar diquark one (as for QCD-inspired NJL models), then in the color symmetric phase pseudo-scalar diquarks are not allowed to exist as stable particles.

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“…It was proposed in the 1960s that the competition between the pair breaking and the pair condensation would induce an unconventional superconducting phase, the Larkin-OvchinnikovFulde-Ferrel (LOFF) state [1]. Recently it was found that if the mismatch is larger than the gap magnitude, a gapless superconducting phase [2,3] or a breached pairing (BP) [4] can be formed in a charge neutral quark matter or in a constrained imbalanced cold atom system, respectively. Another scenario for the ground state at moderate mismatch is the phase separation [5] between of superfluid/superconducting and normal phases.…”

mentioning

confidence: 99%

“…The explicit form of Ω M has been given in Ref. [2] with the Sarma instability [19], 12) in weak coupling, i.e. δµ <<μ.…”

mentioning

confidence: 99%

Higgs instability in gapless superfluidity/superconductivity

et al. 2007

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In this letter we explore the Higgs instability in the gapless superfluid/superconducting phase. This is in addition to the (chromo)magnetic instability that is related to the fluctuations of the Nambu-Goldstone bosonic fields. While the latter may induce a single-plane-wave LOFF state, the Higgs instability favors spatial inhomogeneity and cannot be removed without a long range force. In the case of the g2SC state the Higgs instability can only be partially removed by the electric Coulomb energy. But this does not exclude the possibility that it can be completely removed in other exotic states such as the gCFL state. 12.38.Aw, 26.60.+c Superfluidity or superconductivity with mismatched Fermi momenta appears in many systems such as the charge neutral dense quark matter, the asymmetric nuclear matter, and in imbalanced cold atomic gases. The mismatch plays the role of breaking the Cooper pairing. But it is not understood how a BCS superconductor is destroyed as the mismatch is increased. It was proposed in the 1960s that the competition between the pair breaking and the pair condensation would induce an unconventional superconducting phase, the Larkin-OvchinnikovFulde-Ferrel (LOFF) state [1]. Recently it was found that if the mismatch is larger than the gap magnitude, a gapless superconducting phase [2,3] or a breached pairing (BP) [4] can be formed in a charge neutral quark matter or in a constrained imbalanced cold atom system, respectively. Another scenario for the ground state at moderate mismatch is the phase separation[5] between of superfluid/superconducting and normal phases.Both gapless superconducting and BP phases exhibit instabilities. The former exhibits a chromomagnetic instability [6,7] while the latter a superfluid density instability [8]. Recent studies have demonstrated that this type of instability is related to the local phase fluctuation of the superconducting order parameter, i.e., the Nambu-Goldstone boson fields [9,10,11,12]. This type of instability induces the formation of the single-planewave FF-like state [13,14,15,16,17].The imbalanced cold atom systems such as the 40 K and 6 Li offer an intriguing experimental opportunity to understand the pair breaking states. However, recent experiments [18] on these systems did not show explicit evidence of the BP state or the LOFF state, rather they produced strong evidence of the phase separation at moderate mismatch. We explain in this letter that the BP state or the FF state maybe prevented to form there because of the Higgs instability induced by the mismatch. The Higgs instability is related to the magnitude fluctuation of the superconducting order parameter, i.e., the Higgs field. It causes spatial inhomogeneity that may lead to phase separation. The Higgs instability was also considered in [20], where it was named "amplitude instability".The Higgs instability is an inhomogeneous extension of the Sarma instability against a homogeneous variation of the order parameter. Consider a system described by the Hamiltonian H with a spontaneous ...

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Charge neutrality effects on two-flavor color superconductivity

Cited by 126 publications

References 24 publications

Deconfinement transition in protoneutron stars: Analysis within the Nambu–Jona-Lasinio model

Deconfinement transition in protoneutron stars: Analysis within the Nambu–Jona-Lasinio model

Mesons and diquarks in the color neutral superconducting phase of dense cold quark matter

Higgs instability in gapless superfluidity/superconductivity

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