Holographic anisotropic model for light quarks with confinement-deconfinement phase transition

Abstract

We present a five-dimensional anisotropic holographic model for light quarks supported by Einstein-dilaton-two-Maxwell action. This model generalizing isotropic holographic model with light quarks is characterized by a Van der Waals-like phase transition between small and large black holes. We compare the location of the phase transition for Wilson loops with the positions of the phase transition related to the background instability and describe the QCD phase diagram in the thermodynamic plane — temperature T and chemical potential μ. The Cornell potential behavior in this anisotropic model is also studied. The asymptotics of the Cornell potential at large distances strongly depend on the parameter of anisotropy and orientation. There is also a nontrivial dependence of the Cornell potential on the boundary conditions of the dilaton field and parameter of anisotropy. With the help of the boundary conditions for the dilaton field one fits the results of the lattice calculations for the string tension as a function of temperature in isotropic case and then generalize to the anisotropic one.

Holographic model for heavy quarks in anisotropic hot dense QGP with external magnetic field

“…The form of deformation is chosen to reproduce a typical for heavy quarks phase structure, supported by lattice calculations. Deformation of the metric for light quarks is different [16,28,47], and this agrees with the so-called Columbia plot [78][79][80].…”

“…To deal with anisotropic HQCD one considers Einstein-dilaton-two Maxwell model with additional Maxwell field to support the anisotropy in metrics. Such anisotropic model was considered to reconstruct the picture of the phase transition characteristic of heavy quarks [30] and light quarks [47]. Note that we do not actually calculate quark masses and include them into the action and EOM.…”

“…and V (φ) is the scalar field potential. Thus (2.1) is the extended version of the action used in [30,47], where we add an external magnetic field F (B) µν . To consider action (2.1) let us take the ansatz in the following view:…”

“…µν . Choice of A(z) determines the heavy/light quarks version of the model, so we follow previous works and consider A(z) = − cz 2 /4 for "heavy quarks" [30] and A(z) = − a ln(bz 2 + 1) for "light quarks" [47].…”

“…The form of the integration boundary z 0 = z 0 (z h ) determines the string tension behavior in the model. This aspect was discussed in more details in [47,54]. Excluding anisotropy and normalizing to the AdS-radius, i.e.…”