Dynamic critical phenomena at a holographic critical point

TL;DR

This paper investigates the behavior of transport coefficients near a holographic critical point in a five-dimensional black hole model of the QCD phase diagram, revealing finite coefficients but diverging derivatives and vanishing diffusion at criticality.

Contribution

It provides a detailed analysis of transport properties near a holographic critical point, highlighting the suppression of convective transport in large-N_c gauge theories.

Findings

Transport coefficients remain finite at the critical point.

Diffusion constant approaches zero near the critical point.

Divergence observed in low-temperature bulk viscosity.

Abstract

We study time-dependent perturbations to a family of five-dimensional black hole spacetimes constructed as a holographic model of the QCD phase diagram. We use the results to calculate two transport coefficients, the bulk viscosity and conductivity, as well as the associated baryon diffusion constant, throughout the phase diagram. Near the critical point in the T-mu plane, the transport coefficients remain finite, although their derivatives diverge, and the diffusion goes to zero. This provides further evidence that large-N_c gauge theories suppress convective transport. We also find a divergence in the low-temperature bulk viscosity, outside the region expected to match QCD, and compare the results to the transport behavior of known R-charged black holes.