scholarly journals Study of phases in a holographic QCD model

Author(s):  
Varun Sethi

Witten–Sakai–Sugimoto model is used to study Yang–Mills theory with flavors and large number of colors at finite temperature and in the presence of chemical potential for baryon number and isospin. Sources for [Formula: see text] and [Formula: see text] gauge fields on the flavor 8-branes are D4-branes wrapped on [Formula: see text] part of the background. Here, gauge symmetry on the flavor branes has been decomposed as [Formula: see text] and [Formula: see text] is within [Formula: see text] and generated by the diagonal generator. We show various brane configurations, along with the phases in the boundary theory they correspond to, and explore the possibility of phase transition between various pairs of phases.

2008 ◽  
Vol 23 (14n15) ◽  
pp. 2251-2252 ◽  
Author(s):  
MASAFUMI ISHIHARA ◽  
KAZUO GHOROKU ◽  
AKIHIRO NAKAMURA

N = 2 supersymmetric Yang-Mills theory with flavor hypermultiplets at finite temperature is studied for finite quark number density (nb) by a dual supergravity background with nontrivial dilaton and axion. The quarks and their number density nb are introduced by embeddings a probe D7 brane. We find a critical value of the chemical potential at the limit of nb = 0, and it coincides with the effective quark mass for nb = 0. At this point, a transition of the D7 embedding configurations occurs between their two typical ones. The phase diagrams of this transition are shown in the plane of chemical potential versus temperature for Yang-Mills theory at finite temperature. In this phase transition, the order parameter is considered as nb. This result seems to be reasonable since this theory is in the quark deconfiment phase.


2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Xun Chen ◽  
Lin Zhang ◽  
Danning Li ◽  
Defu Hou ◽  
Mei Huang

Abstract We investigate rotating effect on deconfinement phase transition in an Einstein-Maxwell-Dilaton (EMD) model in bottom-up holographic QCD approach. By constructing a rotating black hole, which is supposed to be dual to rotating strongly coupled nuclear matter, we investigate the thermodynamic quantities, including entropy density, pressure, energy density, trace anomaly, sound speed and specific heat for both pure gluon system and two-flavor system under rotation. It is shown that those thermodynamic quantities would be enhanced by large angular velocity. Also, we extract the information of phase transition from those thermodynamic quantities, as well as the order parameter of deconfinement phase transition, i.e. the loop operators. It is shown that, in the T − ω plane, for two-flavor case with small chemical potential, the phase transition is always crossover. The transition temperature decreases slowly with angular velocity and chemical potential. For pure gluon system with zero chemical potential, the phase transition is always first order, while at finite chemical potential a critical end point (CEP) will present in the T − ω plane.


2019 ◽  
Vol 34 (01) ◽  
pp. 1950003
Author(s):  
Yu-Qiang Cui ◽  
Zhong-Liang Pan

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.


2003 ◽  
Vol 655 (1-2) ◽  
pp. 170-184 ◽  
Author(s):  
K. Farakos ◽  
P. de Forcrand ◽  
C.P. Korthals Altes ◽  
M. Laine ◽  
M. Vettorazzo

1993 ◽  
Vol 08 (07) ◽  
pp. 1295-1312 ◽  
Author(s):  
D. EBERT ◽  
YU. L. KALINOVSKY ◽  
L. MÜNCHOW ◽  
M.K. VOLKOV

An extended NJL model with [Formula: see text] and (qq)-interactions is studied at finite temperature and baryon number density. We investigate the chiral symmetry breaking, its restoration and the behavior of meson and diquark masses, decay and coupling constants as functions of T and µ.


Author(s):  
Zhu-Fang Cui ◽  
Yi-Lun Du ◽  
Hong-Shi Zong

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.


Sign in / Sign up

Export Citation Format

Share Document