scholarly journals Holographic quark matter with color superconductivity and a stiff equation of state for compact stars

2021 ◽  
Vol 103 (2) ◽  
Author(s):  
Kazem Bitaghsir Fadafan ◽  
Jesús Cruz Rojas ◽  
Nick Evans
Keyword(s):  
Equation Of State ◽  
Quark Matter ◽  
Compact Stars ◽  
Color Superconductivity ◽  
Stiff Equation

scholarly journals Relativistic Cowling approximation for fluid oscillation modes of color superconducting self-bound stars

2012 ◽  
Vol 8 (S291) ◽  
pp. 451-451
Author(s):  
German Lugones ◽  
Cesar Vasquez Flores
Keyword(s):  
Equation Of State ◽  
Gravitational Waves ◽  
Internal Structure ◽  
Quark Matter ◽  
Normal Modes ◽  
Pressure Oscillation ◽  
Compact Stars ◽  
Color Superconductivity ◽  
Strange Stars ◽  
Oscillation Modes

AbstractThe investigation of the quasi-normal modes of oscillation of compact stars can reveal much information about their equation of state and internal structure mainly through the analysis of the expected emission of gravitational waves. In this work we study non-radial oscillation modes of strange stars consisting of color superconducting quark matter. We focus on the fundamental and pressure oscillation modes within the frame of the Cowling approximation. We discuss the observable features that may allow a differentiation among hadronic stars, strange stars, and strange stars with color superconductivity.

scholarly journals CAN COLD QUARK MATTER BE SOLID?

2010 ◽  
Vol 19 (08n10) ◽  
pp. 1437-1446 ◽  
Author(s):  
R. XU
Keyword(s):  
Solid State ◽  
Interaction Energy ◽  
Ground State ◽  
Quark Matter ◽  
Fermi Gas ◽  
The State ◽  
Compact Stars ◽  
Color Superconductivity ◽  
Many Body ◽  
Coupling Treatment

The state of cold quark matter challenges both astrophysicists and particle physicists, and even many-body physicists. It is conventionally suggested that BCS-like color superconductivity occurs in cold quark matter; however, other scenarios with a ground state rather than of Fermi gas could still be possible. It is addressed that quarks are dressed and clustered in cold quark matter at realistic baryon densities of compact stars, since a weakly coupling treatment of the interaction between constituent quarks would not be reliable. Cold quark matter is conjectured to be in a solid state if thermal kinematic energy is much lower than the interaction energy of quark clusters, and such a state could be relevant to different manifestations of pulsar-like compact stars.

scholarly journals Compact Star Properties from an Extended Linear Sigma Model

Universe ◽  
2019 ◽  
Vol 5 (7) ◽  
pp. 174
Author(s):  
János Takátsy ◽  
Péter Kovács ◽  
Zsolt Szép ◽  
György Wolf
Keyword(s):  
Equation Of State ◽  
Quark Matter ◽  
Sigma Model ◽  
Equations Of State ◽  
Compact Star ◽  
Axial Vector ◽  
Compact Stars ◽  
Linear Sigma Model ◽  
Axial Vector Meson ◽  
Effective Models

The equation of state provided by effective models of strongly interacting matter should comply with the restrictions imposed by current astrophysical observations of compact stars. Using the equation of state given by the (axial-)vector meson extended linear sigma model, we determine the mass–radius relation and study whether these restrictions are satisfied under the assumption that most of the star is filled with quark matter. We also compare the mass–radius sequence with those given by the equations of state of somewhat simpler models.

scholarly journals INVESTIGATION OF THE EXISTENCE OF HYBRID STARS USING NAMBU–JONA–LASINIO MODELS

2010 ◽  
Vol 19 (08n10) ◽  
pp. 1521-1524 ◽  
Author(s):  
J. G. COELHO ◽  
C. H. LENZI ◽  
M. MALHEIRO ◽  
R. M. MARINHO ◽  
M. FIOLHAIS
Keyword(s):  
Phase Transition ◽  
Equation Of State ◽  
Neutron Stars ◽  
Quark Matter ◽  
Chemical Potential ◽  
Compact Stars ◽  
Vector Coupling ◽  
Njl Model ◽  
Hybrid Stars ◽  
Quark Phase

We investigate the hadron-quark phase transition inside neutron stars and obtain mass–radius relations for hybrid stars. The equation of state for the quark phase using the standard NJL model is too soft, leading to an unstable star and suggesting a modification of the NJL model by introducing a momentum cutoff dependent on the chemical potential. However, even in this approach, the instability remains. In order to remedy the instability we suggest the introduction of a vector coupling in the NJL model, which makes the EoS stiffer, reducing the instability. We conclude that the possible existence of quark matter inside the stars require high densities, leading to very compact stars.

SELF-LENSING EFFECTS FOR COMPACT STARS AND THEIR MASS–RADIUS RELATION

2004 ◽  
Vol 19 (32) ◽  
pp. 2431-2435
Author(s):  
A. R. PRASANNA ◽  
SUBHARTHI RAY
Keyword(s):  
General Relativity ◽  
Neutron Star ◽  
Equation Of State ◽  
Quark Matter ◽  
Strange Quark ◽  
Strange Quark Matter ◽  
Compact Stars ◽  
Strange Stars ◽  
Lensing Effect ◽  
R Relation

During the last couple of years astronomers and astrophysicists have been debating on the fact whether the so-called "strange stars" — stars made up of strange quark matter, have been discovered with the candidates like SAX J1808.4–3658, 4U 1728–34, RX J1856.5–3754, etc. The main contention has been the estimation of radius of the star for an assumed mass of ~ 1.4 M⊙ and to see whether the point overlaps with the graphs for the neutron star equation of state or whether it goes to the region of stars made of strange matter equation of state. Using the well-established formulae from general relativity for the gravitational redshift and the "lensing effect" due to bending of photon trajectories, we, in this letter, relate the parameters M and R with the observable parameters, the redshift z and the radiation radius R∞, thus constraining both M and R for specific ranges, without any other arbitrariness. With the required inputs from observations, one ought to incorporate the effects of self-lensing of the compact stars which has been otherwise ignored in all of the estimations done so far. Nonetheless, these effects of self-lensing make a marked difference for constraints on the M–R relation.

COLOR SUPERCONDUCTIVITY IN DENSE QUARK MATTER

2007 ◽  
Vol 16 (09) ◽  
pp. 2748-2762
Author(s):  
MICHAEL BUBALLA
Keyword(s):  
Phase Diagram ◽  
Quark Matter ◽  
Low Temperatures ◽  
Compact Stars ◽  
Color Superconductivity ◽  
Qcd Phase Diagram ◽  
Dense Quark Matter

The possible structure of the QCD phase diagram is discussed focusing on color superconducting quark matter in the region of low temperatures and moderately large densities which could be relevant for compact stars.

scholarly journals INTERACTING QUARK MATTER EQUATION OF STATE FOR COMPACT STARS

2014 ◽  
Vol 781 (2) ◽  
pp. L25 ◽  
Author(s):  
Eduardo S. Fraga ◽  
Aleksi Kurkela ◽  
Aleksi Vuorinen
Keyword(s):  
Equation Of State ◽  
Quark Matter ◽  
Compact Stars
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