scholarly journals Lattice Constraints on the QCD Chiral Phase Transition at Finite Temperature and Baryon Density

Symmetry ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2079
Author(s):  
Owe Philipsen
Keyword(s):  
Phase Transition ◽  
Chemical Potential ◽  
Baryon Density ◽  
Variable Number ◽  
Current Data ◽  
Crossover Region ◽  
Chiral Phase ◽  
Quark Masses ◽  
Sign Problem ◽  
Genuine Solution

The thermal restoration of chiral symmetry in QCD is known to proceed by an analytic crossover, which is widely expected to turn into a phase transition with a critical endpoint as the baryon density is increased. In the absence of a genuine solution to the sign problem of lattice QCD, simulations at zero and imaginary baryon chemical potential in a parameter space enlarged by a variable number of quark flavours and quark masses constitute a viable way to constrain the location of a possible non-analytic phase transition and its critical endpoint. In this article I review recent progress towards an understanding of the nature of the transition in the massless limit, and its critical temperature at zero density. Combined with increasingly detailed studies of the physical crossover region, current data bound a possible critical point to μB ≳ 3T.

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.

PHASE TRANSITION PATTERNS OF NUCLEAR MATTER BASED ON EXTENDED LINEAR SIGMA MODEL

2013 ◽  
Vol 22 (11) ◽  
pp. 1350077 ◽  
Author(s):  
TRAN HUU PHAT ◽  
NGUYEN TUAN ANH ◽  
PHUNG THI THU HA
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
Nuclear Matter ◽  
Degrees Of Freedom ◽  
Sigma Model ◽  
Chemical Potential ◽  
Linear Sigma Model ◽  
Baryon Chemical Potential ◽  
Chiral Phase ◽  
The Relationship

We study systematically various types of phase transitions in nuclear matter at finite temperature T and baryon chemical potential μ based on the extended linear sigma model with nucleon degrees of freedom. It is shown that there are three types of phase transitions in nuclear matter: the chiral symmetry nonrestoration (SNR) at high temperature, the well-known liquid–gas (LG) phase transition at sub-saturation density and the Lifshitz phase transition (LPT) from the fully-gapped state to the state with Fermi surface. Their phase diagrams are established in the (T, μ)-plane and their physical properties are investigated in detail. The relationship between the chiral phase transition and the LG phase transition in nuclear matter is discussed.

scholarly journals Chiral phase transition in two-flavor QCD from an imaginary chemical potential

2014 ◽  
Vol 90 (7) ◽  
Author(s):  
Claudio Bonati ◽  
Philippe de Forcrand ◽  
Massimo D’Elia ◽  
Owe Philipsen ◽  
Francesco Sanfilippo
Keyword(s):  
Phase Transition ◽  
Chemical Potential ◽  
Chiral Phase ◽  
Chiral Phase Transition

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.

scholarly journals Chiral symmetry restoration and the critical end point in QCD

Open Physics ◽  
2017 ◽  
Vol 15 (1) ◽  
pp. 1039-1044 ◽  
Author(s):  
Jose Rubén Morones-Ibarra ◽  
Armando Enriquez-Perez-Gavilan ◽  
Abraham Israel Hernández Rodriguez ◽  
Francisco Vicente Flores-Baez ◽  
Nallaly Berenice Mata-Carrizalez ◽  
...  
Keyword(s):  
Phase Transition ◽  
Phase Diagram ◽  
Chemical Potential ◽  
Quark Condensate ◽  
Number Density ◽  
Chiral Symmetry Restoration ◽  
Chiral Phase ◽  
Quark Number ◽  
Quark Number Susceptibility ◽  
Transition Type

AbstractIn a system of quark matter we study the chiral phase transition, the behavior of the chiral and quark number susceptibility and the CEP at finite temperature and chemical potential. This is done within the framework of two-flavor Nambu and Jona-Lasinio model. We have calculated the chiral quark condensate and the quark number density and, with this, we have found the phase transition type. With these quantities we have determined the phase diagram for QCD and the CEP.

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.

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