Interacting Quark Matter Equation of State for Compact Stars

Fraga, Eduardo S.; Kurkela, Aleksi; Vuorinen, Aleksi

doi:10.1088/2041-8205/781/2/l25

Cited by 204 publications

(215 citation statements)

References 48 publications

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“…Here one notes that the gluon resummation gives the enhanced ratio (P (µ)/P ideal (µ) ∼ 1.1 at µ = 1 GeV), while inclusion of the quark resummation gives the reduced ratio (P (µ)/P ideal (µ) ∼ 0.8 at µ = 1 GeV). The reduction of pressure due to the inclusion of quark contributions is consistent with previous studies that include a massive strangeness and the quark interaction part up to O(α 2 s ) [52,53]. Based on the result of Ref.…”

Section: B Hdl Resumed Thermodynamic Potentialsupporting

confidence: 91%

Symmetry energy in cold dense matter

Jeong

Lee

2016

Nuclear Physics A

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We calculate the symmetry energy in cold dense matter both in the normal quark phase and in the 2-color superconductor (2SC) phase. For the normal phase, the thermodynamic potential is calculated by using hard dense loop (HDL) resummation to leading order, where the dominant contribution comes from the longitudinal gluon rest mass. The effect of gluonic interaction to the symmetry energy, obtained from the thermodynamic potential, was found to be small. In the 2SC phase, the non-perturbative BCS paring gives enhanced symmetry energy as the gapped states are forced to be in the common Fermi sea reducing the number of available quarks that can contribute to the asymmetry. We used high density effective field theory to estimate the contribution of gluon interaction to the symmetry energy. Among the gluon rest masses in 2SC phase, only the Meissner mass has iso-spin dependence although the magnitude is much smaller than the Debye mass. As the iso-spin dependence of gluon rest masses is even smaller than the case in the normal phase, we expect that the contribution of gluonic interaction to the symmetry energy in the 2SC phase will be minimal. The different value of symmetry energy in each phase will lead to different prediction for the particle yields in heavy ion collision experiment.

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Section: B Hdl Resumed Thermodynamic Potentialsupporting

confidence: 91%

Symmetry energy in cold dense matter

Jeong

Lee

2016

Nuclear Physics A

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“…We are showing here that if the vacuum energy, which is presumably included in the MIT bag model as part of the bag constant, was to be relaxed towards negligible values, larger values of M max could easily be obtained, improving consistency with observations (see also [26,27]). Nevertheless, it is certainly crucial that a reliable EoS for the matter component is obtained [28][29][30] before making any definitive conclusions.…”

Section: Jhep06(2016)104mentioning

confidence: 99%

Cosmological and astrophysical probes of vacuum energy

Bellazzini

Csáki

Serra

et al. 2016

J. High Energ. Phys.

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Vacuum energy changes during cosmological phase transitions and becomes relatively important at epochs just before phase transitions. For a viable cosmology the vacuum energy just after a phase transition must be set by the critical temperature of the next phase transition, which exposes the cosmological constant problem from a different angle. Here we propose to experimentally test the properties of vacuum energy under circumstances different from our current vacuum. One promising avenue is to consider the effect of high density phases of QCD in neutron stars. Such phases have different vacuum expectation values and a different vacuum energy from the normal phase, which can contribute an order one fraction to the mass of neutron stars. Precise observations of the mass of neutron stars can potentially yield information about the gravitational properties of vacuum energy, which can significantly affect their mass-radius relation. A more direct test of cosmic evolution of vacuum energy could be inferred from a precise observation of the primordial gravitational wave spectrum at frequencies corresponding to phase transitions. While traditional cosmology predicts steps in the spectrum determined by the number of degrees of freedom both for the QCD and electroweak phase transitions, an adjustment mechanism for vacuum energy could significantly change this. In addition, there might be other phase transitions where the effect of vacuum energy could show up as a peak in the spectrum.

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“…The modified bag model EoS has already been used to calculate the structure of non-spinning strange stars (Fraga et al 2001;Alford et al 2005;Weissenborn et al 2011;Fraga et al 2014) and hybrid stars (Alford et al 2005;Weissenborn et al 2011).…”

Section: Introductionmentioning

confidence: 99%

Fast spinning strange stars: possible ways to constrain interacting quark matter parameters

Bhattacharyya

Bombaci

Logoteta

et al. 2016

Mon. Not. R. Astron. Soc.

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For a set of equation of state (EoS) models involving interacting strange quark matter, characterized by an effective bag constant (B eff ) and a perturbative QCD corrections term (a 4 ), we construct fully general relativistic equilibrium sequences of rapidly spinning strange stars for the first time. Computation of such sequences is important to study millisecond pulsars and other fast spinning compact stars. Our EoS models can support a gravitational mass (M G ) and a spin frequency (ν) at least up to ≈ 3.0M ⊙ and ≈ 1250 Hz respectively, and hence are fully consistent with measured M G and ν values. This paper reports the effects of B eff and a 4 on measurable compact star properties, which could be useful to find possible ways to constrain these fundamental quark matter parameters, within the ambit of our EoS models. We confirm that a lower B eff allows a higher mass. Besides, for known M G and ν, measurable parameters, such as stellar radius, radius-to-mass ratio and moment of inertia, increase with the decrease of B eff . Our calculations also show that a 4 significantly affects the stellar rest mass and the total stellar binding energy. As a result, a 4 can have signatures in evolutions of both accreting and non-accreting compact stars, and the observed distribution of stellar mass and spin and other source parameters. Finally, we compute the parameter values of two important pulsars, PSR J1614-2230 and PSR J1748-2446ad, which may have implications to probe their evolutionary histories, and for constraining EoS models.

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Interacting Quark Matter Equation of State for Compact Stars

Cited by 204 publications

References 48 publications

Symmetry energy in cold dense matter

Symmetry energy in cold dense matter

Cosmological and astrophysical probes of vacuum energy

Fast spinning strange stars: possible ways to constrain interacting quark matter parameters

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