Quark number susceptibility with finite chemical potential in holographic QCD (original) (raw)
Related papers
Quark Number Susceptibility with Finite Quark Mass in Holographic QCD
2010
We study the effect of a finite quark mass on the quark number susceptibility in the framework of holographic QCD. We work in a bottom-up model with a deformed AdS black hole and D3/D7 model to calculate the quark number susceptibility at finite temperature with/without a finite quark chemical potential. As expected the finite quark mass suppresses the quark number susceptibility. We find that at high temperatures Tge600T\ge 600Tge600 MeV the quark number susceptibility of light quarks and heavy quarks are almost equal in the bottom-up model. This indicates that the heavy quark like charm contribution to thermodynamics of a QCD-like system may start to become significant at temperatures Tsim600T\sim 600Tsim600 MeV. In D3/D7 model, we focus on the competition between the quark chemical potential, which enhances the quark number susceptibility, and the quark mass that suppresses the susceptibility. We observe that depending on the relative values of the quark mass and the quark chemical potential, the quark number susceptibility shows a diverging or converging behavior. We also calculate the chiral susceptibility in D3/D7 model to support the observation made with the quark number susceptibility.
Quark Number Susceptibilities and Equation of State in QCD at Finite μB
Proceedings
One of the main goals of the cold baryonic matter (CBM) experiment at FAIR is to explore the phases of strongly interacting matter at finite temperature and baryon chemical potential μ B . The equation of state of quantum chromodynamics (QCD) at μ B > 0 is an essential input for the CBM experiment, as well as for the beam energy scan in the Relativistic Heavy Ion Collider(RHIC) experiment. Unfortunately, it is highly nontrivial to calculate the equation of state directly from QCD: numerical Monte Carlo studies on lattice are not useful at finite μ B . Using the method of Taylor expansion in chemical potential, we estimate the equation of state, namely the baryon number density and its contribution to the pressure, for two-flavor QCD at moderate μ B . We also study the quark number susceptibilities. We examine the technicalities associated with summing the Taylor series, and explore a Pade resummation. An examination of the Taylor series can be used to get an estimate of the locat...
1999
We explore the phase diagram of SU(2) Lattice Gauge Theory with dynamical fermions in the temperature, mass, chemical potential space. We observe qualitative changes of the dependence of the particle density on mu\mumu and TTT, which is compatible with that expected of a gas of free massless quarks nproptomu3n \propto \mu^3nproptomu3 only for TsimeqTcT \simeq T_cTsimeqTc. At the onset for thermodynamics the interquark potential flattens at large separations, indicating enhanced fermion screening and the transition to a deconfined phase. Temporal and spatial Polyakov loops behave in different ways, the latter being nearly insensitive to the chemical potential. The rotation of the chiral condensate to a baryonic condensate, as inferred from the susceptibilities, might occur together with a reduction of its magnitude in the chiral limit, possibly leading to a critical temperature for diquark condensation smaller than the deconfinement temperature. We further asses the r\^ole of the chemical potential into the gauge dynamics by carrying out a partial quenched calculation. We speculate on the relevance, or lack thereof, of our findings to real QCD.
0 10 30 13 v 1 1 5 M ar 2 00 1 Quark number susceptibilities , strangeness and dynamical confinement
2008
We report first results on the strange quark number susceptibility, χs, over a large range of temperatures, mainly in the plasma phase of QCD. χs jumps across the phase transition temperature, Tc, and grows rapidly with temperature above but close to Tc. For all quark masses and susceptibilities in the entire temperature range studied, we found significant departures from ideal-gas values. We also observed a strong correlation between these quantities and the susceptibility in the scalar/pseudo-scalar channel, supporting ideas of “dynamical confinement” in the high temperature phase of the QCD plasma.
Holographic QCD and magnetic fields
The European Physical Journal A
We review the holographic approach to electromagnetic phenomena in large N QCD. After a brief discussion of earlier holographic models, we concentrate on the improved holographic QCD model extended to involve magnetically induced phenomena. We explore the influence of magnetic fields on the QCD ground state, focusing on (inverse) magnetic catalysis of chiral condensate, investigate the phase diagram of the theory as a function of magnetic field, temperature and quark chemical potential, and, finally discuss effects of magnetic fields on the quark–anti-quark potential, shear viscosity, speed of sound and magnetization.
Phys Rev D, 2007
We explore the highly non-perturbative hot region of the QCD phase diagram close to Tc by use of an imaginary chemical potential mu which avoids the sign problem. The number density and the quark number susceptibility are consistent with a critical behaviour associated with the transition line in the negative mu^2 half-plane. We compare the analytic continuation of these results with various phenomenological models, none of which provides a satisfactory description of data, a failure on which we make some comments. These results complement and extend the information obtained via the analysis of the susceptibilities evaluated at zero mu, yielding a simple description of the candidate strongly interacting QGP phase. As a byproduct of our analysis we investigate the Polyakov loop and its hermitian conjugate. Our data offer a vivid evidence of the importance of the complex nature of the functional integral measure, which results in L (mu) ne \bar L(mu) for a real chemical potential.