scholarly journals Effects of Hadron-Quark Phase Transitions in Hybrid Stars within the NJL Model

Symmetry ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 425 ◽  
Author(s):  
Ignacio Ranea-Sandoval ◽  
Milva Orsaria ◽  
Germán Malfatti ◽  
Daniela Curin ◽  
Mauro Mariani ◽  
...  
Keyword(s):  
Phase Transition ◽  
Mean Field ◽  
Temperature Limit ◽  
Hadronic Matter ◽  
Transition Diagram ◽  
Mean Field Model ◽  
Relativistic Mean Field ◽  
Non Local ◽  
Gibbs Formalism ◽  
Hybrid Stars

We study local and non-local Polyakov Nambu-Jona-Lasinio models and analyze their respective phase transition diagram. We construct hybrid stars using the zero temperature limit of the local and non-local versions of Nambu-Jona-Lasinio model for quark matter and the modern GM1(L) parametrization of the non-linear relativistic mean field model for hadronic matter. We compare our models with data from PSR J1614-2230 and PSR J0343+0432 and also from GW170817 and its electromagnetic counterpart GRB170817A and AT2017gfo. We study observational signatures of the appearance of a mixed phase as a result of modeling a phase transition that mimics the Gibbs formalism and compare the results with the sharp first-order phase transition obtained using the Maxwell construction. We also study in detail the g-mode associated with discontinuities in the equation of state, and calculate non-radial oscillation modes using relativistic Cowling approximation.

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).

RADIAL PULSATIONS OF HYBRID NEUTRON STARS

2012 ◽  
Vol 18 ◽  
pp. 105-108 ◽  
Author(s):  
C. VÁSQUEZ FLORES ◽  
C. H. LENZI ◽  
G. LUGONES
Keyword(s):  
Stability Criterion ◽  
Mean Field ◽  
Oscillation Mode ◽  
Maximum Mass ◽  
Mean Field Model ◽  
Relativistic Mean Field ◽  
Hadron Phase ◽  
Njl Model ◽  
Hybrid Stars ◽  
The Stability

In this work we investigate the adiabatic radial oscillations of hybrid stars. We use a relativistic-mean-field model equation of state (EOS) to describe the hadron phase and the Nambu-Jona-Lasinio (NJL) model for the quark matter phase. We integrate the equations of relativistic radial oscillations using different parameterizations for the NJL model and investigate the effect of a first order hadron-quark phase transition on the fundamental oscillation mode. The results show that the period τ of the fundamental mode is characterized by a cusp on the maximum mass and is finite for some configurations beyond the maximum mass. We conclude that for hybrid stars with sharp discontinuities the standard stability criterion ∂M/∂εc > 0 is not coincident with the stability criterion based on the finiteness of τ.

scholarly journals PROPERTIES OF MAGNETIZED QUARK-HYBRID STARS

2011 ◽  
Vol 20 (supp02) ◽  
pp. 25-28
Author(s):  
MILVA ORSARIA ◽  
IGNACIO F. RANEA-SANDOVAL ◽  
H. VUCETICH ◽  
FRIDOLIN WEBER
Keyword(s):  
Magnetic Field ◽  
Field Equation ◽  
Equation Of State ◽  
Uniform Magnetic Field ◽  
Mean Field ◽  
Hadronic Matter ◽  
Relativistic Mean Field ◽  
Standard Neutron ◽  
Hybrid Stars ◽  
Mean Field Equation

The structure of a magnetized quark-hybrid stars (QHS) is modeled using a standard relativistic mean-field equation of state (EoS) for the description of hadronic matter. For quark matter we consider a bag model EoS which is modified perturbatively to account for the presence of a uniform magnetic field. The mass-radius (M-R) relationship, gravitational redshift and rotational Kepler periods of such stars are compared with those of standard neutron stars (NS).

scholarly journals Phases of Hadron-Quark Matter in (Proto) Neutron Stars

Universe ◽  
2019 ◽  
Vol 5 (7) ◽  
pp. 169 ◽  
Author(s):  
Fridolin Weber ◽  
Delaney Farrell ◽  
William M. Spinella ◽  
Germán Malfatti ◽  
Milva G. Orsaria ◽  
...  
Keyword(s):  
Neutron Stars ◽  
Quark Matter ◽  
Mean Field Theory ◽  
Mean Field ◽  
Hadronic Matter ◽  
Relativistic Mean Field ◽  
Quark Flavor ◽  
Flavor Mixing ◽  
Non Local ◽  
Quark Deconfinement

In the first part of this paper, we investigate the possible existence of a structured hadron-quark mixed phase in the cores of neutron stars. This phase, referred to as the hadron-quark pasta phase, consists of spherical blob, rod, and slab rare phase geometries. Particular emphasis is given to modeling the size of this phase in rotating neutron stars. We use the relativistic mean-field theory to model hadronic matter and the non-local three-flavor Nambu–Jona-Lasinio model to describe quark matter. Based on these models, the hadron-quark pasta phase exists only in very massive neutron stars, whose rotational frequencies are less than around 300 Hz. All other stars are not dense enough to trigger quark deconfinement in their cores. Part two of the paper deals with the quark-hadron composition of hot (proto) neutron star matter. To this end we use a local three-flavor Polyakov–Nambu–Jona-Lasinio model which includes the ’t Hooft (quark flavor mixing) term. It is found that this term leads to non-negligible changes in the particle composition of (proto) neutron stars made of hadron-quark matter.

EVOLUTION OF SHELL STRUCTURE IN NUCLEI

2011 ◽  
Vol 20 (08) ◽  
pp. 1663-1675 ◽  
Author(s):  
A. BHAGWAT ◽  
Y. K. GAMBHIR
Keyword(s):  
Shell Structure ◽  
Crucial Role ◽  
Field Model ◽  
Mean Field ◽  
Mass Region ◽  
The Other ◽  
Mean Field Model ◽  
Relativistic Mean Field ◽  
Shell Closures ◽  
Low Mass

Systematic investigations of the pairing and two-neutron separation energies which play a crucial role in the evolution of shell structure in nuclei, are carried out within the framework of relativistic mean-field model. The shell closures are found to be robust, as expected, up to the lead region. New shell closures appear in low mass region. In the superheavy region, on the other hand, it is found that the shell closures are not as robust, and they depend on the particular combinations of neutron and proton numbers. Effect of deformation on the shell structure is found to be marginal.

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.

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