Collective modes in anisotropic plasmas

TL;DR

This paper investigates the collective excitations in anisotropic quark-gluon plasmas, revealing complex dispersion relations and enhanced imaginary modes influenced by anisotropy and chiral chemical potential, using a comprehensive tensor basis and quasi-particle approach.

Contribution

It introduces a complete tensor basis for analyzing gluon polarization in anisotropic plasmas with chiral asymmetry, expanding understanding of collective modes beyond simple deformations.

Findings

Dispersion relations are richer with generalized anisotropic distributions.

Imaginary modes are more prominent and sensitive to anisotropy.

Small chiral chemical potentials have amplified effects in anisotropic conditions.

Abstract

We study collective modes in anisotropic plasmas of quarks and gluons using a quasi-particle picture and a hard loop approximation. We use a general class of anisotropic distribution functions, and we consider chirally asymmetric systems. We introduce a complete tensor basis to decompose the gluon polarization tensor into a set of nine scalar functions. We derive and solve the corresponding dispersion equations. Imaginary modes are particularly important because of their potential influence on plasma dynamics. We explore in detail their dependence on the chiral chemical potential and the parameters that characterise the anisotropy of the system. We show that our generalized distributions produce dispersion relations that are much richer in structure than those obtained with a simple one parameter deformation of an isotropic distribution. In addition, the size and domain of the imaginary solutions are enhanced, relative to those obtained with a one parameter deformation. Finally, we show that the influence of even a very small chiral chemical potential is significantly magnified when anisotropy is present.