Refractive index in the viscous quark-gluon plasma

Abstract

Under the framework of the viscous chromohydrodynamics, the gluon self-energy is derived for the quark-gluon plasma with shear viscosity. The viscous electric permittivity and magnetic permeability are evaluated from the gluon self-energy, through which the refraction index is investigated. The numerical analysis indicates that the refractive index becomes negative in some frequency range. The start point for that frequency range is around the electric permittivity pole, and the magnetic permeability pole determines the end point. As the increase of η/s, the frequency range for the negative refraction becomes wider.

Color-electric conductivity in a viscous quark-gluon plasma

“…[23,24], the authors have extended the ideal chromohydrodynamic equations [47,85,86] to the viscous ones by expanding the collisionless kinetic equation ( 2) in momentum moments in terms of distribution function modified by shear viscosity (4). It is argued that chromohydrodynamics can describe the polarization effect as the kinetic theory [24,86]. In addition, the fluid equations dealing with conservative equations of the macroscopic physical quantities are much simpler than those of the kinetic theory.…”

“…In those equations, n, ǫ and p represent the particle density, the energy density and pressure respectively. Usually, hydrodynamic quantities have both colorless and colorful parts, as an example, the particle density can be written as [23,24,86]…”

“…The relativistic hydrodynamic simulations associated with a small shear viscosity rather successfully explain the flow data and transverse momentum spectra of ultimate hadron from heavy ion collisions, for reviews please refer to Refs [1][2][3][4][5]. Soon afterwards the viscous effects on the diverse aspects of the hot QGP, including photon and dilepton production [6,7], heavy quarkonium dissolution [8,9], energy loss suffered by the fast parton traveling through the QGP [10][11][12][13] and the induced wakes [14][15][16][17][18], the quark polarization [19] and the chiral magnetic/vortical effects [20][21][22], the dielectric properties of the QGP medium [23][24][25] and the dynamical evolution of QCD matter during the first-order phase transition from hadronic matter to quark matter [26], have been addressed in recent years.…”

Electromagnetic response of strongly coupled plasmas

“…The former implies that the electromagnetic energy flux and the phase velocity of an electromagnetic wave through the medium propagate in opposite directions [6,[12][13][14][15][16][17][18][19][20][21][22]; the latter means that, even if isotropic, a medium supports multiple electromagnetic waves with the same frequency but different wave-vectors [7][8][9][10][11]. Following these results, various authors investigated these topics in a wide variety of different setups, see for example [26][27][28][29][30][31][32][33][34][35][36]. In particular [37] provides an analysis of the actual signature of the abovementioned phenomena in condensed matter systems and it proposes suitable experiments to measure such effects.…”

Refractive index in generalized superconductors with Born–Infeld electrodynamics

“…Other investigations based on the refractive index in the holographic dual models can be found, for example, in Refs. [23][24][25][26][27][28][29][30][31][32].…”