scholarly journals Hadron-quark phase transition in dense matter and neutron stars

2002 ◽  
Vol 66 (2) ◽  
Author(s):  
G. F. Burgio ◽  
M. Baldo ◽  
P. K. Sahu ◽  
H.-J. Schulze
Keyword(s):  
Phase Transition ◽  
Neutron Stars ◽  
Dense Matter ◽  
Quark Phase

scholarly journals Does a hadron-quark phase transition in dense matter preclude the existence of massive neutron stars?

2012 ◽  
Vol 8 (S291) ◽  
pp. 356-358 ◽  
Author(s):  
N. Chamel ◽  
A. F. Fantina ◽  
J. M. Pearson ◽  
S. Goriely
Keyword(s):  
Phase Transition ◽  
Equation Of State ◽  
Neutron Stars ◽  
Nuclear Energy ◽  
Dense Matter ◽  
Density Functionals ◽  
Nuclear Mass ◽  
Neutron Star Mass ◽  
The Impact ◽  
Quark Phase

AbstractWe study the impact of a hadron-quark phase transition on the maximum neutron-star mass. The hadronic part of the equation of state relies on the most up-to-date Skyrme nuclear energy density functionals, fitted to essentially all experimental nuclear mass data and constrained to reproduce the properties of infinite nuclear matter as obtained from microscopic calculations using realistic forces. We show that the softening of the dense matter equation of state due to the phase transition is not necessarily incompatible with the existence of massive neutron stars like PSR J1614–2230.

scholarly journals Stellar Collapse with Hadron-Quark Phase Transition of Hot and Dense Matter

2008 ◽  
Vol 174 ◽  
pp. 76-79
Author(s):  
Ken'ichiro Nakazato ◽  
Kohsuke Sumiyoshi ◽  
Shoichi Yamada
Keyword(s):  
Phase Transition ◽  
Dense Matter ◽  
Stellar Collapse ◽  
Quark Phase

scholarly journals Non-local quark models for description of dense matter in the cores of neutron stars

2020 ◽  
Author(s):  
◽  
Germán Malfatti
Keyword(s):  
Phase Transition ◽  
Neutron Stars ◽  
Quark Matter ◽  
Equations Of State ◽  
Cold Neutron ◽  
Dense Matter ◽  
Superconducting Phase ◽  
Coupling Constants ◽  
Hadronic Matter ◽  
Free Parameters

This thesis work focuses on studying the possible existence of phase transitions in the immediate compact remnants of core collapse supernova, neutron stars, and the theoretical models that describe the interior of dense matter. Specifically, we are interested in analyzing the feasibility of a transition from hadronic matter to quark matter in the cores of these objects. The density of matter inside neutron stars is several times that of atomic nuclei, and the equation of state that describes such matter in such a regime is still unknown. In this context, it is known that the interaction between the constituents of nucleons, the quarks, weakens with increasing density due to the intrinsic property of the QCD known as it asymptotic freedom. Therefore, matter should either dissolve into a quark-free state at high densities, or else form a superconduct- ing state of color. This superconducting phase of color would be energetically favorable, if it were present in a cold neutron star, since a system of fermions that interact weakly at low temperature is unstable with respect to the formation of Cooper pairs. Although it is impossible to know both theoretically and experimentally whether these phases exist in neutron stars, the interpolation of the resolvable part of QCD at high densities, together with the hadronic equations of state at low densities, suggest that they could appear in the interior of compact objects. For the phase transition we will use two different formalisms: the Maxwell formalism, in which an abrupt phase transition between hadronic and quark matter without mixed phase formation is assumed, and the Gibbs formalism, in which a mixed phase in which hadrons and quarks coexist. For the description of hadronic matter, we will use different parametrizations of the relativistic mean field model with density-dependent coupling constants. For the description of quark matter we will use an effective nonlocal Nambu Jona-Lasinio model of three flavors with vector interactions, in which we will include the possibility of formation of diquarks to model a superconducting phase of color in SU (3), which we will call 2SC + s. Phase diagrams and equations of state of quark matter at finite temperature are presented, and the influence of that kind of matter on observables associated with neutron stars is investigated. Likewise, using hybrid equations of state, the simplified thermal evolution of compact stars during their formation is studied, from their state of proto-neutron stars to that of cold neutron stars, and the results obtained are compared with recent astrophysical observations. The pa- rameterizations used in this work are adjusted to the most recent measurements of masses and coupling constants of the QCD, which imposes strong restrictions on the existence of quark matter in proto-stars, unlike what happens with less realistic models or with more free parameters. However, the results obtained indicate that even considering these restrictions, the occurrence of quark matter in the nuclei of these stars remains a promis- ing possibility. The remaining free parameters of the models were adjusted taking into account the observational restrictions, coming from precise determinations of the pulsars masses of ∼ 2 M⊙, and the event corresponding to the fusion of two neutron stars, known as GW170817. The fact that the use of more realistic models for the description of the dense matter in these objects indicates the presence of quark matter inside neutron stars, could be an answer to the question of the behavior of that kind of matter and the determination of its corresponding equation of state.

scholarly journals Evolution of proto-neutron stars with hadron–quark phase transition

2012 ◽  
Vol 342 ◽  
pp. 012001 ◽  
Author(s):  
Ignazio Bombaci ◽  
Domenico Logoteta ◽  
Constança Providencia ◽  
Isaac Vidaña
Keyword(s):  
Phase Transition ◽  
Neutron Stars ◽  
Quark Phase

ON THE CONFINED–DECONFINED PHASE TRANSITION IN NUCLEAR MATTER AND NEUTRON STARS

2010 ◽  
Vol 19 (08n10) ◽  
pp. 1563-1568 ◽  
Author(s):  
L. N. BURIGO ◽  
B. E. J. BODMANN ◽  
R. B. JACOBSEN ◽  
C. A. Z. VASCONCELLOS ◽  
F. FERNÁNDEZ
Keyword(s):  
Phase Transition ◽  
Neutron Stars ◽  
Baryon Number ◽  
Local Conservation ◽  
Independent Components ◽  
First Order ◽  
Mit Bag Model ◽  
Effective Theories ◽  
Quark Phase ◽  
Hadronic Model

In this work we focus our study on the transition from hadron to deconfined quark matter, and we shall assume that the phase transition is first-order with two independent components, which are related to the local conservation of baryon number and the global conservation of electric charge. Relativistic effective theories are employed to describe the hadron and quark phase. Two different hadronic models are adopted: an adjustable model and the well known Boguta–Bodmer model. Deconfined phase is described employing the MIT bag model. Previous studies showed that the choice of the hadronic model as well as its parameters (including nucleon effective mass and hyperonic coupling schemes) have influence on phase transition properties. Our aim is to analyze if such results on phase transition play an important role on the modeling of neutron stars. To carry out such analysis, the Tolman–Oppenheimer–Volkoff equations are employed to determine the maximum mass for each combination of hadronic model and parameters.

HADRON-QUARK PHASE TRANSITION AND ANTIKAON CONDENSATION IN NEUTRON STARS

2008 ◽  
Vol 23 (27n30) ◽  
pp. 2481-2484
Author(s):  
H. SHEN ◽  
F. YANG ◽  
P. YUE
Keyword(s):  
Field Theory ◽  
Phase Transition ◽  
Equation Of State ◽  
Neutron Stars ◽  
Mean Field Theory ◽  
Mean Field ◽  
Maximum Mass ◽  
Relativistic Mean Field ◽  
The Core ◽  
Quark Phase

We study the hadron-quark phase transition and antikaon condensation which may occur in the core of massive neutron stars. The relativistic mean field theory is used to describe the hadronic phase, while the Nambu-Jona-Lasinio model is adopted for the quark phase. We find that the hadron-quark phase transition is very sensitive to the models used. The appearance of deconfined quark matter and antikaon condensation can soften the equation of state at high density and lower the maximum mass of neutron stars.

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