Lowest eigenvalues of the Dirac operator for two color QCD at nonzero chemical potential

TL;DR

This paper studies the eigenvalue spectrum of the Dirac operator in two-color QCD and related gauge theories at finite chemical potential, revealing universal behavior in some regimes and non-universality in others.

Contribution

It provides a detailed analysis of the low-lying Dirac spectrum across different gauge theories and phases, highlighting where random matrix theory applies and where it does not.

Findings

Universal spectral behavior along the strong-coupling axis up to phase transition

No universality observed in microscopic spectral densities in the chirally symmetric phase

Different spectral properties for theories with minimal coupling

Abstract

We investigate the eigenvalue spectrum of the staggered Dirac matrix in SU(3) and U(1) gauge theory as well as in full QCD with two colors and finite chemical potential. Along the strong-coupling axis up to the phase transition, the low-lying Dirac spectrum of these quantum field theories is well described by random matrix theory and exhibits universal behavior. Related results for gauge theories with minimal coupling are discussed in the chirally symmetric phase and no universality is seen for the microscopic spectral densities.