Thermodynamics and Instabilities of a Strongly Coupled Anisotropic Plasma

TL;DR

This paper investigates the thermodynamics and stability of a strongly coupled, anisotropic plasma using holographic duality, revealing phase structures, instabilities, and connections to QCD phenomena.

Contribution

It extends supergravity solutions to analyze anisotropic plasmas, uncovering phase behavior, instabilities, and the role of conformal anomalies in thermodynamics.

Findings

Identification of homogeneous and inhomogeneous phases.

Discovery of instabilities similar to weakly coupled plasmas.

Analysis of phase diagram with anisotropic and mixed phases.

Abstract

We extend our analysis of a IIB supergravity solution dual to a spatially anisotropic finite-temperature N=4 super Yang-Mills plasma. The solution is static, possesses an anisotropic horizon, and is completely regular. The full geometry can be viewed as a renormalization group flow from an AdS geometry in the ultraviolet to a Lifshitz-like geometry in the infrared. The anisotropy can be equivalently understood as resulting from a position-dependent theta-term or from a non-zero number density of dissolved D7-branes. The holographic stress tensor is conserved and anisotropic. The presence of a conformal anomaly plays an important role in the thermodynamics. The phase diagram exhibits homogeneous and inhomogeneous (i.e. mixed) phases. In some regions the homogeneous phase displays instabilities reminiscent of those of weakly coupled plasmas. We comment on similarities with QCD at finite baryon density and with the phenomenon of cavitation.