scholarly journals A QCD chiral critical point at small chemical potential: is it there or not?

Author(s):  
Philippe de Forcrand
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.


2018 ◽  
Vol 182 ◽  
pp. 02066
Author(s):  
Evgeni E. Kolomeitsev ◽  
Maxim E. Borisov ◽  
Dmitry N. Voskresensky

We consider a non-ideal hot pion gas with the dynamically fixed number of particles in the model with the λφ4 interaction. The effective Lagrangian for the description of such a system is obtained by dropping the terms responsible for the change of the total particle number. Within the self-consistent Hartree approximation, we compute the effective pion mass, thermodynamic characteristics of the system and identify a critical point of the induced Bose-Einstein condensation when the pion chemical potential reaches the value of the effective pion mass. The normalized variance, skewness, and kurtosis of the particle number distributions are calculated. We demonstrate that all these characteristics remain finite at the critical point of the Bose-Einstein condensation. This is due to the non-perturbative account of the interaction and is in contrast to the ideal-gas case.


2011 ◽  
Author(s):  
Kim Splittorff ◽  
Maria-Paola Lombardo ◽  
Jacobus Verbaarschot

2020 ◽  
Vol 29 (01) ◽  
pp. 2050003 ◽  
Author(s):  
Masatoshi Morimoto ◽  
Yasuhiko Tsue ◽  
João da Providência ◽  
Constança Providência ◽  
Masatoshi Yamamura

A possibility of a quark spin polarization originating from a pseudovector condensate is investigated in the three-flavor Nambu–Jona–Lasinio model with the Kobayashi–Maskawa–’t Hooft interaction which leads to flavor mixing. It is shown that a pseudovector condensate related to the strange quark easily occurs compared with pseudovector condensate related to light quarks. Further, it is shown that the pseudovector condensate related to the strange quark appears at a slightly small chemical potential by the effect of the flavor mixing due to the Kobayashi–Maskawa–’t Hooft interaction.


2020 ◽  
Vol 2020 (10) ◽  
Author(s):  
Navid Abbasi ◽  
Sara Tahery

Abstract We develop a method to study coupled dynamics of gauge-invariant variables, constructed out of metric and gauge field fluctuations on the background of a AdS5 Reissner-Nordström black brane. Using this method, we compute the numerical spectrum of quasinormal modes associated with fluctuations of spin 0, 1 and 2, non-perturbatively in μ/T . We also analytically compute the spectrum of hydrodynamic excitations in the small chemical potential limit. Then, by studying the spectral curve at complex momenta in every spin channel, we numerically find points at which hydrodynamic and non-hydrodynamic poles collide. We discuss the relation between such collision points and the convergence radius of the hydrodynamic derivative expansion. Specifically in the spin 0 channel, we find that within the range $$ 1.1\underset{\sim }{<}\mu /T\underset{\sim }{<}2 $$ 1.1 < ∼ μ / T < ∼ 2 , the radius of convergence of the hydrodynamic sound mode is set by the absolute value of the complex momentum corresponding to the point at which the sound pole collides with the hydrodynamic diffusion pole. It shows that in holographic systems at finite chemical potential, the convergence of the hydrodynamic derivative expansion in the mentioned range is fully controlled by hydrodynamic informa- tion. As the last result, we explicitly show that the relevant information about quantum chaos in our system can be extracted from the pole-skipping points of energy density re- sponse function. We find a threshold value for μ/T , lower than which the pole-skipping points can be computed perturbatively in a derivative expansion.


2007 ◽  
Vol 75 (11) ◽  
Author(s):  
K. Splittorff ◽  
J. J. M. Verbaarschot

2003 ◽  
Vol 119 ◽  
pp. 541-543 ◽  
Author(s):  
Ph. de Forcrand ◽  
S. Kim ◽  
T. Takaishi

2012 ◽  
Vol 26 (29) ◽  
pp. 1250144
Author(s):  
N. KRISTOFFEL ◽  
P. RUBIN

The pseudogap (PG) excitation is analyzed as a natural event in multiband superconductivity. It corresponds to minimal quasiparticle excitation energy of an electron band not touched by the chemical potential. The critical points of the phase diagram are determined by vanishing conditions for normal state pseudogaps (NPG). For two bands (gapped or overlapping) these are positioned on edges of the superconducting dome. Theoretical background for a three-band system with two interband pairing channels is developed. There are three independent superconducting gaps (SCG). The PG is associated with the band component possessing a bare gap which can be quenched by doping. At low doping the PG and the SCG of another band component coexist. The critical point is not fixed in respect of the transition temperature (Tc) dome background. The depletion of the PG associated states is restored here. This effect can also be indirect by the participation of these states in determining the chemical potential position. At the critical point the PG looses its normal state contribution and continues as the SCG of the same band. Illustrative examples on the doping scale have been calculated.


Sign in / Sign up

Export Citation Format

Share Document