A Topology-Changing Phase Transition and the Dynamics of Flavour

TL;DR

This paper investigates a first order phase transition in a large N_c SU(N_c) gauge theory with fundamental quarks at finite temperature, using holographic duality, revealing topology changes in D-brane configurations and effects on the meson spectrum.

Contribution

It demonstrates a topology-changing phase transition in the holographic dual of a gauge theory, linking D-brane topology shifts to physical phase changes and meson spectrum modifications.

Findings

Identification of a first order phase transition at finite quark mass.

Topology change in D-brane solutions corresponds to the phase transition.

Observable effects on the meson spectrum near the transition.

Abstract

In studying the dynamics of large N_c, SU(N_c) gauge theory at finite temperature with fundamental quark flavours in the quenched approximation, we observe a first order phase transition. A quark condensate forms at finite quark mass, and the value of the condensate varies smoothly with the quark mass for generic regions in parameter space. At a particular value of the quark mass, there is a finite discontinuity in the condensate's vacuum expectation value, corresponding to a first order phase transition. We study the gauge theory via its string dual formulation using the AdS/CFT conjecture, the string dual being the near-horizon geometry of N_c D3-branes at finite temperature, AdS_5--Schwarzschild X S^5, probed by a D7-brane. The D7-brane has topology R^4 X S^3 X S^1 and allowed solutions correspond to either the S^3 or the S^1 shrinking away in the interior of the geometry. The phase transition represents a jump between branches of solutions having these two distinct D-brane topologies. The transition also appears in the meson spectrum.