scholarly journals Nonstrange quark stars from an NJL model with proper-time regularization

2019 ◽  
Vol 100 (12) ◽  
Author(s):  
Qingwu Wang ◽  
Chao Shi ◽  
Hong-Shi Zong
Keyword(s):  
Proper Time ◽  
Quark Stars ◽  
Njl Model

scholarly journals Strange quark stars within proper time regularized ( 2+1 )-flavor NJL model

2020 ◽  
Vol 101 (6) ◽  
Author(s):  
Cheng-Ming Li ◽  
Shu-Yu Zuo ◽  
Yan Yan ◽  
Ya-Peng Zhao ◽  
Fei Wang ◽  
...  
Keyword(s):  
Strange Quark ◽  
Proper Time ◽  
Quark Stars ◽  
Njl Model

Conversion of neutron stars to 2 + 1 flavor Nambu–Jona-Lasinio quark stars as a mechanism for gamma-ray bursts

2017 ◽  
Vol 32 (37) ◽  
pp. 1750209
Author(s):  
Xiao-Yu Shu ◽  
Yong-Feng Huang ◽  
Hong-Shi Zong
Keyword(s):  
Phase Transition ◽  
Gamma Ray ◽  
Chemical Potential ◽  
Proper Time ◽  
Mean Field ◽  
Gamma Ray Bursts ◽  
Compact Stars ◽  
Relativistic Mean Field ◽  
Quark Stars ◽  
Njl Model

The phase transition from a neutron star to a quark star and its relation to gamma-ray bursts are investigated. A new model: the 2 + 1 flavor Nambu–Jona-Lasinio (NJL) model with the method of proper-time regularization (PTR) is utilized for the quark phase; while the Relativistic Mean Field (RMF) theory is used for the hadronic phase. The process of phase transition is studied by considering the chemical potential, paying special attention to the phase transition point and the emergence of strange quark matter. Characteristics of compact stars are illustrated, and the energy release during the phase transition is found to be [Formula: see text] erg.

Studies on proper time regularization and the QCD chiral phase transition

2019 ◽  
Vol 34 (01) ◽  
pp. 1950003
Author(s):  
Yu-Qiang Cui ◽  
Zhong-Liang Pan
Keyword(s):  
Phase Transition ◽  
Small Parameter ◽  
Effective Mass ◽  
Finite Temperature ◽  
Chemical Potential ◽  
Proper Time ◽  
Chiral Phase ◽  
Chiral Phase Transition ◽  
Njl Model ◽  
The Difference

We investigate the finite-temperature and zero quark chemical potential QCD chiral phase transition of strongly interacting matter within the two-flavor Nambu–Jona-Lasinio (NJL) model as well as the proper time regularization. We use two different regularization processes, as discussed in Refs. 36 and 37, separately, to discuss how the effective mass M varies with the temperature T. Based on the calculation, we find that the M of both regularization schemes decreases when T increases. However, for three different parameter sets, quite different behaviors will show up. The results obtained by the method in Ref. 36 are very close to each other, but those in Ref. 37 are getting farther and farther from each other. This means that although the method in Ref. 37 seems physically more reasonable, it loses the advantage in Ref. 36 of a small parameter dependence. In addition, we also, find that two regularization schemes provide similar results when T [Formula: see text] 100 MeV, while when T is larger than 100 MeV, the difference becomes obvious: the M calculated by the method in Ref. 36 decreases more rapidly than that in Ref. 37.

Proper time regularization at finite quark chemical potential

2016 ◽  
Vol 31 (14) ◽  
pp. 1650086 ◽  
Author(s):  
Jin-Li Zhang ◽  
Yuan-Mei Shi ◽  
Shu-Sheng Xu ◽  
Hong-Shi Zong
Keyword(s):  
Phase Transition ◽  
Chemical Potential ◽  
Chiral Limit ◽  
Proper Time ◽  
Quark Confinement ◽  
Chiral Phase ◽  
Chiral Phase Transition ◽  
Njl Model ◽  
Potential Case ◽  
Chiral Susceptibility

In this paper, we use the two-flavor Nambu–Jona-Lasinio (NJL) model to study the quantum chromodynamics (QCD) chiral phase transition. To deal with the ultraviolet (UV) issue, we adopt the popular proper time regularization (PTR), which is commonly used not only for hadron physics but also for the studies with magnetic fields. This regularization scheme can introduce the infrared (IR) cutoff to include quark confinement. We generalize the PTR to zero temperature and finite chemical potential case use a completely new method, and then study the chiral susceptibility, both in the chiral limit case and with finite current quark mass. The chiral phase transition is second-order in [Formula: see text] and [Formula: see text] and crossover at [Formula: see text] and [Formula: see text]. Three sets of parameters are used to make sure that the results do not depend on the parameter choice.

The two-flavor NJL model with two-cutoff proper time regularization

2014 ◽  
Vol 29 ◽  
pp. 1460232 ◽  
Author(s):  
Zhu-Fang Cui ◽  
Yi-Lun Du ◽  
Hong-Shi Zong
Keyword(s):  
Phase Transition ◽  
Finite Temperature ◽  
Chemical Potential ◽  
Proper Time ◽  
Model Parameters ◽  
Chiral Phase ◽  
Chiral Phase Transition ◽  
Regularization Scheme ◽  
Njl Model

In this paper, we use the two-flavor Nambu–Jona-Lasinio model together with the proper time regularization that has both ultraviolet and infrared cutoffs to study the chiral phase transition at finite temperature and zero chemical potential. The involved model parameters in our calculation are determined in the traditional way. Our calculations show that the dependence of the results on the choice of the parameters are really small, which can then be regarded as an advantage besides such a regularization scheme is Lorentz invariant.

On the stability of two-flavor and three-flavor quark matter in quark stars within the framework of NJL model

2020 ◽  
Vol 35 (39) ◽  
pp. 2050321 ◽  
Author(s):  
Qianyi Wang ◽  
Tong Zhao ◽  
Hongshi Zong
Keyword(s):  
Quark Matter ◽  
Mean Field ◽  
Field Approximation ◽  
Mean Field Approximation ◽  
Chiral Phase ◽  
Quark Stars ◽  
Njl Model ◽  
The Stability ◽  
Chiral Susceptibility ◽  
Strong Interaction Matter

Following our recently proposed self-consistent mean field approximation approach, we have done some researches on the chiral phase transition of strong interaction matter within the framework of Nambu-Jona-Lasinio (NJL) model. The chiral susceptibility and equation of state (EOS) are computed in this work for both two-flavor and three-flavor quark matter for contrast. The Pauli–Villars scheme, which can preserve gauge invariance, is used in this paper. Moreover, whether the three-flavor quark matter is more stable than the two-flavor quark matter or not in quark stars is discussed in this work. In our model, when the bag constant are the same, the two-flavor quark matter has a higher pressure than the three-flavor quark matter, which is different from what Witten proposed in his pioneering work.

scholarly journals NAMBU–JONA–LASINIO MODEL IN CURVED SPACETIME WITH MAGNETIC FIELD

1996 ◽  
Vol 11 (25) ◽  
pp. 2053-2063 ◽  
Author(s):  
B. GEYER ◽  
L.N. GRANDA ◽  
S.D. ODINTSOV
Keyword(s):  
Magnetic Field ◽  
Gravitational Field ◽  
Chiral Symmetry ◽  
Proper Time ◽  
Chiral Symmetry Breaking ◽  
Curved Spacetime ◽  
Njl Model ◽  
Nonzero Curvature ◽  
Curvature Approximation ◽  
The Magnetic Field

We discuss the phase structure of the NJL model in curved spacetime with magnetic field using 1/N-expansion and linear curvature approximation. The effective potential for composite fields [Formula: see text] is calculated using the proper-time cutoff in the following cases: (a) at nonzero curvature, (b) at nonzero curvature and nonzero magnetic field, and (c) at nonzero curvature and nonzero covariantly constant gauge field. Chiral symmetry breaking is studied numerically. We show that the gravitational field may compensate the effect of the magnetic field what leads to restoration of chiral symmetry.

scholarly journals Structure of Hot Strange Quark Stars: an NJL Model Approach at Finite Temperature

Astrophysics ◽  
2019 ◽  
Vol 62 (2) ◽  
pp. 276-290 ◽  
Author(s):  
G. H. Bordbar ◽  
R. Hosseini ◽  
F. Kayanikhoo ◽  
A. Poostforush
Keyword(s):  
Finite Temperature ◽  
Strange Quark ◽  
Quark Stars ◽  
Njl Model ◽  
Model Approach

scholarly journals Solving the Gap Equation of the NJL Model through Iterations: Unexpected Chaos

Symmetry ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 492
Author(s):  
Angelo Martínez ◽  
Alfredo Raya
Keyword(s):  
Magnetic Field ◽  
Iterative Procedure ◽  
Proper Time ◽  
Thermal Bath ◽  
Coupling Constant ◽  
Regularization Scheme ◽  
Gap Equation ◽  
A Value ◽  
Njl Model

We explore the behavior of the iterative procedure to obtain the solution to the gap equation of the Nambu-Jona-Lasinio (NLJ) model for arbitrarily large values of the coupling constant and in the presence of a magnetic field and a thermal bath. We find that the iterative procedure shows a different behavior depending on the regularization scheme used. It is stable and very accurate when a hard cut-off is employed. Nevertheless, for the Paul-Villars and proper time regularization schemes, there exists a value of the coupling constant (different in each case) from where the procedure becomes chaotic and does not converge any longer.

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