Large N Phase Transitions and Multi-Critical Behaviour in Generalized 2D QCD

TL;DR

This paper explores the complex phase structure of generalized 2D Yang-Mills theory at large N, revealing multi-critical points and third order phase transitions across various topologies, unlike ordinary 2D Yang-Mills.

Contribution

It introduces a matrix model approach to analyze the phase transitions and multi-critical behavior of generalized 2D Yang-Mills theory at large N.

Findings

Identifies multi-critical points in the phase diagram.

Discovers third order phase transitions at all genera except the torus.

Contrasts the phase structure with ordinary 2D Yang-Mills theory.

Abstract

Using matrix model techniques we investigate the large N limit of generalized 2D Yang-Mills theory. The model has a very rich phase structure. It exhibits multi-critical behavior and reveals a third order phase transitions at all genera besides {\it torus}. This is to be contrasted with ordinary 2D Yang-Mills which, at large N, exhibits phase transition only for spherical topology.