scholarly journals Identifying QCD Phase Transitions via the Gravitational Wave Frequency from a Supernova Explosion

2021 ◽  
Vol 922 (2) ◽  
pp. 266
Author(s):  
Zhan Bai ◽  
Wei-jie Fu ◽  
Yu-xin Liu
Keyword(s):  
Strange Quark ◽  
Degrees Of Freedom ◽  
Supernova Explosion ◽  
Strange Quark Matter ◽  
The Other ◽  
Qcd Phase Transition ◽  
Quark Stars ◽  
Mit Bag Model ◽  
Strong Interaction Matter ◽  
Nonradial Oscillations

Abstract We investigate the nonradial oscillations of newly born neutron stars (NSs) and strange quark stars (SQSs). This is done with the relativistic nuclear field theory with hyperon degrees of freedom employed to describe the equation of state (EoS) for the stellar matter in NSs, and with both the MIT bag model and the Nambu–Jona-Lasinio model adopted to construct the configurations of the SQSs. We find that the gravitational-mode (g-mode) eigenfrequencies of newly born SQSs are significantly lower than those of NSs, which is independent of models implemented to describe the EoS for the strange quark matter. Meanwhile, the eigenfrequencies of the other modes of nonradial oscillations, e.g., fundamental (f)- and pressure (p)-modes, are much larger than those of the g-mode, and are related to the stiffness of the EoSs. In light of the first direct observation of gravitational waves (GWs), it is promising to employ GWs to identify the QCD phase transition in high-density strong-interaction matter.

scholarly journals MASS–RADIUS RELATION FOR MAGNETIZED STRANGE QUARKS STARS

2010 ◽  
Vol 19 (08n10) ◽  
pp. 1511-1519 ◽  
Author(s):  
A. P. MARTÍNEZ ◽  
R. G. FELIPE ◽  
D. M. PARET
Keyword(s):  
Magnetic Field ◽  
Quark Matter ◽  
Strange Quark ◽  
Baryon Density ◽  
Strange Quark Matter ◽  
Strange Quarks ◽  
Quark Stars ◽  
Mit Bag Model ◽  
The Stability ◽  
The Magnetic Field

We review the stability of magnetized strange quark matter (MSQM) within the phenomenological MIT bag model, taking into account the variation of the relevant input parameters, namely, the strange quark mass, baryon density, magnetic field and bag parameter. A comparison with magnetized asymmetric quark matter in β-equilibrium as well as with strange quark matter (SQM) is presented. We obtain that the energy per baryon for MSQM decreases as the magnetic field increases, and its minimum value at vanishing pressure is lower than the value found for SQM, which implies that MSQM is more stable than non-magnetized SQM. The mass–radius relation for magnetized strange quark stars is also obtained in this framework.

Strange Quark Matter as Dark Matter

2019 ◽  
Vol 22 (4) ◽  
pp. 311-317
Author(s):  
Hidezumi Terazawa
Keyword(s):  
Dark Matter ◽  
Quark Matter ◽  
Strange Quark ◽  
Strange Quark Matter ◽  
Quark Stars

New forms of matter such as super-hypernuclei (strange quark matter) and superhypernuclear stars (strange quark stars) as candidates for dark matter are discussed in some detail, based on the so-called "Bodmer–Terazawa–Witten hypothesis" assuming that they are stable absolutely or quasi-stable (decaying only weakly).

scholarly journals Strange Quark Stars — A Review

2003 ◽  
Vol 214 ◽  
pp. 191-198 ◽  
Author(s):  
R. X. Xu
Keyword(s):  
Neutron Stars ◽  
Quark Matter ◽  
Strange Quark ◽  
Major Part ◽  
Strange Quark Matter ◽  
Strange Stars ◽  
Quark Stars

A pedagogical overview of strange quark matter and strange stars is presented. After a historical notation of the research and an introduction to quark matter, a major part is devoted to the physics and astrophysics of strange stars, with attention being paid to the possible ways by which neutron stars and strange stars can be distinguished in astrophysics. Recent possible evidence for bare strange stars is also discussed.

scholarly journals QUARK STARS AND QUANTUM-MAGNETICALLY INDUCED COLLAPSE

2005 ◽  
Vol 14 (11) ◽  
pp. 1959-1969 ◽  
Author(s):  
A. PÉREZ MARTÍNEZ ◽  
H. PÉREZ ROJAS ◽  
H. J. MOSQUERA CUESTA ◽  
M. BOLIGAN ◽  
M. G. ORSARIA
Keyword(s):  
Neutron Stars ◽  
Magnetic Moment ◽  
Anomalous Magnetic Moment ◽  
Quark Matter ◽  
Strange Quark ◽  
Vacuum Energy Density ◽  
Bag Model ◽  
X Ray ◽  
Quark Stars ◽  
Mit Bag Model

Quark matter is expected to exist in the interior of compact stellar objects as neutron stars or even the more exotic strange stars, based on the Bodmer–Witten conjecture. Bare strange quark stars and (normal) strange quark-matter stars, those possessing a baryon (electron-supported) crust, are hypothesized as good candidates to explain the properties of a set of peculiar stellar sources such as the enigmatic X-ray source RX J1856.5-3754, some pulsars such as PSR B1828-11 and PSR B1642-03, and the anomalous X-ray pulsars and soft γ-ray repeaters. In the MIT bag model, quarks are treated as a degenerate Fermi gas confined to a region of space having a vacuum energy density B bag (the Bag constant). In this note, we modify the MIT bag model by including the electromagnetic interaction. We also show that this version of the MIT model implies the anisotropy of the bag pressure due to the presence of the magnetic field. The equations of state of the degenerate quarks gases are studied in the presence of ultra strong magnetic fields. The behavior of a system made up of quarks having (or not) anomalous magnetic moment is reviewed. A structural instability is found, which is related to the anisotropic nature of the pressures in this highly magnetized matter. The conditions for the collapse of this system are obtained and compared to a previous model of neutron stars that is built on a neutron gas having anomalous magnetic moment.

MAGNETIC FIELD AND TEMPERATURE EFFECTS ON STRANGELETS

2011 ◽  
Vol 20 (supp02) ◽  
pp. 42-49
Author(s):  
ERNESTO LÓPEZ FUNE ◽  
AURORA PÉREZ MARTÍNEZ ◽  
DARYEL MANREZA PARET ◽  
RICARDO GONZÁLEZ FELIPE
Keyword(s):  
Magnetic Field ◽  
Electric Charge ◽  
Quark Matter ◽  
Temperature Effects ◽  
Strange Quark ◽  
Strange Quark Matter ◽  
Mit Bag Model ◽  
Phase Temperature ◽  
Matter Phase ◽  
The Magnetic Field

The main properties of magnetized strangelets, namely, their energy per baryon, radius and electric charge, are studied in the unpaired strange quark matter phase. Temperature effects are taken into account in order to study their stability compared to the 56Fe isotope and non-magnetized strangelets within the framework of the MIT bag model. It is concluded that the presence of a magnetic field tends to stabilize more the strangelets, even when temperature is considered. We find that the electric charge is modified in the presence of the magnetic field, leading to higher charge values for magnetized strangelets, when compared to the non-magnetized case.

scholarly journals Properties of strange quark matter and strange quark stars

2021 ◽  
Vol 81 (9) ◽  
Author(s):  
Manisha Kumari ◽  
Arvind Kumar
Keyword(s):  
Quark Matter ◽  
Strange Quark ◽  
Present Model ◽  
Constituent Quark ◽  
Mean Field ◽  
Strange Quark Matter ◽  
Model Calculations ◽  
Quark Stars ◽  
Star Evolution ◽  
Constituent Quark Mass

AbstractA Polyakov chiral $$\text {SU(3)}$$ SU(3) quark mean-field (PCQMF) model is applied to study the properties of strange quark matter (SQM) and strange quark star (SQS) in $$\beta $$ β -equilibrium. The effect of increasing the strength of vector interactions on the effective constituent quark mass, particle fractions, and the thermodynamical properties such as pressure, energy density, and the speed of sound is investigated. We investigate the above properties for the SQM relevant for various stages of star evolution, i.e., considering with/without trapped neutrinos and zero/finite entropy. The finite lepton fraction and the entropy of the medium is observed to cause the stiffness in the equation of state (EoS). Finally, we calculate the mass-radius relation and the dimensionless tidal deformability within the present model calculations and compare the results to the recent studies.

STRANGE STARS AT VACUUM PRESSURE DEPENDENT ON QUARK DENSITY

2017 ◽  
Vol 51 (1 (242)) ◽  
pp. 71-76
Author(s):  
Yu.L. Vartanyan ◽  
A.K. Grigoryan ◽  
H.A. Shahinyan
Keyword(s):  
Quark Matter ◽  
Strange Quark ◽  
Equations Of State ◽  
Strange Quark Matter ◽  
Vacuum Pressure ◽  
Equilibrium Equations ◽  
Strange Stars ◽  
Mit Bag Model ◽  
Limiting Value ◽  
Tov Equation

Equation of state of strange quark matter has been studied in the framework of MIT bag model, when vacuum pressure $B$ depends on concentration of baryons $n$. The actuality of such studies is conditioned by the increasing of quark matter density from surface to star center. In the literature there exist different representations of function $B(n)$. In the present work Gaussian parametrization is used, which is based on the idea of existence of asymptotic limiting value of this parameter. For four groups of parameters the equations of state of quark matter were determined. The main integral parameters of star configurations were obtained by numerically integrating of star equilibrium equations (the TOV equation). In the considered case it turns that when vacuum pressure dependence on concentration of baryons is taken into account, configurations of strange stars have maximal masses less than two solar masses.   Erratum: Proc. YSU A: Phys. Math. Sci. 52 (2018), 68

scholarly journals Reduction of the Mass of the Proto-Quark Star during Cooling

Particles ◽  
2021 ◽  
Vol 4 (1) ◽  
pp. 37-44
Author(s):  
Gevorg Hajyan
Keyword(s):  
Quark Matter ◽  
Finite Temperature ◽  
Supernova Explosion ◽  
Neutrino Emission ◽  
Quark Star ◽  
Bag Model ◽  
Quark Stars ◽  
Mit Bag Model

The integral parameters (mass, radius) of hot proto-quark stars that are formed in supernova explosion are studied. We use the MIT bag model to determine the pressure of up-down and strage quark matter at finite temperature and in the regime where neutrinos are trapped. It is shown that such stars are heated to temperatures of the order of tens of MeV. The maximum possible values of the central temperatures of these stars are determined. It is shown that the energy of neutrinos that are emitted from proto-quark stars is of the order of 250÷300 MeV. Once formed, the proto-quark stars cool by neutrino emission, which leads to a decrease in the mass of these stars by about 0.16–0.25 M⊙ for stars with the rest masses that are in the range Mb=1.22−1.62M⊙.

RIGIDLY ROTATING STRANGE QUARK STARS

2005 ◽  
Vol 14 (03n04) ◽  
pp. 697-705 ◽  
Author(s):  
İHSAN YILMAZ ◽  
HÜSNÜ BAYSAL
Keyword(s):  
General Relativity ◽  
Electromagnetic Field ◽  
Quark Matter ◽  
Strange Quark ◽  
Fluid Model ◽  
Strange Quark Matter ◽  
Rigid Rotation ◽  
Field Equations ◽  
Quark Stars ◽  
Gödel Universe

In this article, we study rotating strange quark stars in the context of general relativity. For this purpose we consider perfect fluid model composed of strange quark matter with electromagnetic field in the Gödel Universe which has rigid rotation. We solve Einstein's field equations by using equation of state for strange quark matter. Also, we discuss the features of obtained solutions.

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