scholarly journals PHASE TRANSITION AND HYBRID STAR IN AN SU(2) CHIRAL SIGMA MODEL

2002 ◽  
Vol 17 (40) ◽  
pp. 2633-2646 ◽  
Author(s):  
P. K. JENA ◽  
L. P. SINGH
Keyword(s):  
Phase Transition ◽  
Nuclear Matter ◽  
Quark Matter ◽  
Sigma Model ◽  
Mean Field ◽  
Maximum Mass ◽  
Hybrid Star ◽  
Field Approach ◽  
Stable Solutions ◽  
Hybrid Stars

We use a modified SU(2) chiral sigma model to study nuclear matter at high density using mean field approach. We also study the phase transition of nuclear matter to quark matter in the interior of highly dense neutron stars. Stable solutions of Tolman–Oppenheimer–Volkoff equations representing hybrid stars are obtained with a maximum mass of 1.69M⊙, radii around 9.3 km and a quark matter core constituting nearly 55–85% of the star radii.

scholarly journals SU(2) Chiral Sigma Model Study of Phase Transition in Hybrid Stars

2003 ◽  
Vol 18 (30) ◽  
pp. 2135-2145 ◽  
Author(s):  
P. K. Jena ◽  
L. P. Singh
Keyword(s):  
Phase Transition ◽  
Neutron Star ◽  
Nuclear Matter ◽  
Quark Matter ◽  
Sigma Model ◽  
Maximum Mass ◽  
Model Study ◽  
Stable Solutions ◽  
Hybrid Stars ◽  
Matter Component

We use a modified SU(2) chiral sigma model to study nuclear matter component and simple bag model for quark matter constituting a neutron star. We also study the phase transition of nuclear matter to quark matter with the mixed phase characterized by two conserved charges in the interior of highly dense neutron stars. Stable solutions of Tolman–Oppenheimer–Volkoff equations representing hybrid stars are obtained with a maximum mass of 1.67M⊙ and radius around 8.9 km.

scholarly journals PHASE TRANSITION AND HYBRID STAR IN A NONLINEAR σ–ω MODEL

1999 ◽  
Vol 08 (02) ◽  
pp. 107-120 ◽  
Author(s):  
S. ACHARYA ◽  
L. MAHARANA ◽  
R. MOHANTY ◽  
P. K. PANDA
Keyword(s):  
Phase Transition ◽  
Nuclear Matter ◽  
Quark Matter ◽  
Equations Of State ◽  
Mean Field Theory ◽  
Mean Field ◽  
Coupling Constant ◽  
Hybrid Star ◽  
Relativistic Mean Field ◽  
Outer Periphery

The phase transition between nuclear matter and quark matter is examined. The relativistic mean field theory (RMF) is considered with interacting nucleons and mesons using TM1 parameter set for the nuclear matter equations of state. It is found that the transition point depends on coupling constant αs and bag pressure. From the study of the structure of a hybrid neutron star, it is observed that the star contains quark matter in the interior and neutron matter on the outer periphery.

scholarly journals Hybrid Stars in the Framework of NJL Models

2017 ◽  
Vol 45 ◽  
pp. 1760026 ◽  
Author(s):  
Gustavo A. Contrera ◽  
Milva Orsaria ◽  
I. F. Ranea-Sandoval ◽  
Fridolin Weber
Keyword(s):  
Phase Transition ◽  
Quark Matter ◽  
Mean Field ◽  
Field Approximation ◽  
Hadronic Matter ◽  
High Mass ◽  
Mean Field Approximation ◽  
Soft Phase ◽  
Non Local ◽  
Hybrid Stars

We compute models for the equation of state (EoS) of the matter in the cores of hybrid stars. Hadronic matter is treated in the non-linear relativistic mean-field approximation, and quark matter is modeled by three-flavor local and non-local Nambu−Jona-Lasinio (NJL) models with repulsive vector interactions. The transition from hadronic to quark matter is constructed by considering either a soft phase transition (Gibbs construction) or a sharp phase transition (Maxwell construction). We find that high-mass neutron stars with masses up to [Formula: see text] may contain a mixed phase with hadrons and quarks in their cores, if global charge conservation is imposed via the Gibbs conditions. However, if the Maxwell conditions is considered, the appearance of a pure quark matter core either destabilizes the star immediately (commonly for non-local NJL models) or leads to a very short hybrid star branch in the mass-radius relation (generally for local NJL models).

scholarly journals Simplified Thermal Evolution of Proto-Hybrid Stars

2017 ◽  
Vol 45 ◽  
pp. 1760041 ◽  
Author(s):  
Mauro Mariani ◽  
Milva Orsaria ◽  
Héctor Vucetich
Keyword(s):  
Phase Transition ◽  
Neutron Stars ◽  
Thermal Evolution ◽  
Late Phase ◽  
Hadronic Matter ◽  
Maximum Mass ◽  
Hybrid Star ◽  
Star Evolution ◽  
Hybrid Stars ◽  
Quark Phase

We study the possibility of a hadron-quark phase transition in the interior of neutron stars, taking into account different schematic evolutionary stages at finite temperature. Furthermore, we analyze the astrophysical properties of hot and cold hybrid stars, considering the constraint on maximum mass given by the pulsars J1614-2230 and J1614-2230. We obtain cold hybrid stars with maximum masses [Formula: see text] M[Formula: see text]. Our study also suggest that during the proto-hybrid star evolution a late phase transition between hadronic matter and quark matter could occur, in contrast with previous studies of proto-neutron stars.

MODIFIED FORM OF VECTOR MESON COUPLING TO STUDY NUCLEAR MATTER AND ITS PHASE TRANSITION TO QUARK MATTER

2000 ◽  
Vol 15 (21) ◽  
pp. 3303-3313
Author(s):  
BINAY MALAKAR
Keyword(s):  
Phase Transition ◽  
Energy Density ◽  
Vector Meson ◽  
Nuclear Matter ◽  
Quark Matter ◽  
Mean Field Theory ◽  
Mean Field ◽  
Theoretic Model ◽  
Vector Mesons ◽  
Scalar Type

In the proposed field theoretic model to study nuclear matter and its phase transition to quark matter, vector mesons (ωμ) have the usual coupling to fermionic currents and also scalar type coupling involving ωμωμ with fermionic fields and scalar mesons. The effect of this modified vector meson interaction for cold symmetric nuclear matter is investigated using relativistic mean-field theory. One of the striking features of the model is that at extremely high density part of the energy density due to vector mesons is proportional to the density ρ (instead of ρ2 as in Walecka model, Boguta model etc.) where Fermi gas energy density varies as ρ4/3.

scholarly journals Maximum mass of hybrid star formed via shock induced phase transition in cold neutron stars

2021 ◽  
Author(s):  
Ritam Mallick ◽  
Shailendra Singh ◽  
Rana Nandi
Keyword(s):  
Phase Transition ◽  
Neutron Star ◽  
Cold Neutron ◽  
Local Maximum ◽  
Global Maximum ◽  
Maximum Pressure ◽  
Maximum Mass ◽  
Hybrid Star ◽  
External Energy ◽  
Hybrid Stars

Abstract This article studies the maximum mass limit of the hybrid star formed after the shock-induced phase transition of a cold neutron star. By employing hadronic and quark equation of state that satisfies the current mass bound, we use combustion adiabat conditions to find such a limit. The combustion adiabat condition results in a local or a global maximum pressure at an intermediate density range. The maximum pressure corresponds to a local or global maximum mass for the phase transformed hybrid star. The phase transition is usually exothermic if we have a local maximum mass. The criteria for exothermic or endothermic phase transition depend on whether the quark pressure/energy ratios to nuclear pressure/energy are smaller or greater than 1. We find that exothermic phase transition in a cold neutron star usually results in hybrid stars whose mass is smaller than a parent neutron star. The phase transition is endothermic for a global maximum pressure; thereby, one gets a global maximum mass. Hybrid stars much massive than phase transformed local maximum mass can be formed, provided there is some external energy source during the phase transition process. However, for some cases, even massive hybrid stars can form with exothermic phase transition for equations of state having global maximum pressure.

NUCLEAR MATTER WITH CONSTITUENT MESON QUANTA

1990 ◽  
Vol 05 (17) ◽  
pp. 3391-3399 ◽  
Author(s):  
AMRUTA MISHRA ◽  
H. MISHRA ◽  
S.P. MISRA
Keyword(s):  
Field Theory ◽  
Nuclear Matter ◽  
Mass Shell ◽  
Mean Field ◽  
S Wave ◽  
Field Approach ◽  
Physical Insight ◽  
The Mean

We discuss here some nonperturbative techniques of field theory, where we dress nuclear matter as a whole with off-mass-shell pions. Here s-wave pion pairs simulate the effect of σ-meson of the mean field approach of Walecka. The signatures are in agreement with earlier results along with new physical insight.

EFFECT OF MAGNETIC FIELD ON THE PHASE TRANSITION FROM NUCLEAR MATTER TO QUARK MATTER DURING PROTO-NEUTRON STAR EVOLUTION

2002 ◽  
Vol 11 (04) ◽  
pp. 545-559 ◽  
Author(s):  
V. K. GUPTA ◽  
ASHA GUPTA ◽  
S. SINGH ◽  
J. D. ANAND
Keyword(s):  
Magnetic Field ◽  
Phase Transition ◽  
Quark Matter ◽  
Mean Field Theory ◽  
Mean Field ◽  
Relativistic Mean Field ◽  
Electron Neutrinos ◽  
Hadron Phase ◽  
Frame Work ◽  
Trapped Electron

We have studied phase transition from hadron matter to quark matter in the presence of high magnetic fields incorporating the trapped electron neutrinos at finite temperatures. We have used the density dependent quark mass (DDQM) model for the quark phase while the hadron phase is treated in the frame-work of relativistic mean field theory. It is seen that the energy density in the hadron phase at phase transition decreases with both magnetic field and temperature.

Sign in / Sign up

Export Citation Format

Share Document