Phase transitions and gluodynamics in 2-colour matter at high density

TL;DR

This study explores the phase structure of 2-colour QCD at high density, revealing weak dependence of the superfluid transition on chemical potential, a decreasing deconfinement temperature, and complex gluon propagator behavior.

Contribution

It provides new insights into the phase transitions and gluodynamics of 2-colour matter at high density and temperature, with detailed lattice simulation results.

Findings

Superfluid to normal transition temperature is weakly dependent on chemical potential.

Deconfinement crossover temperature decreases with increasing chemical potential.

Evidence of a deconfined but superfluid phase at high chemical potential.

Abstract

We investigate 2-colour QCD with 2 flavours of Wilson fermion at nonzero temperature T and quark chemical potential mu, with a pion mass of 700 MeV (m_pi/m_rho=0.8). From temperature scans at fixed mu we find that the critical temperature for the superfluid to normal transition depends only very weakly on mu above the onset chemical potential, while the deconfinement crossover temperature is clearly decreasing with mu. We find indications of a region of superfluid but deconfined matter at high mu and intermediate T. The static quark potential determined from the Wilson loop is found to exhibit a 'string tension' that increases at large mu in the 'deconfined' region. The electric (longitudinal) gluon propagator in Landau gauge becomes strongly screened with increasing temperature and chemical potential. The magnetic (transverse) gluon shows little sensitivity to temperature, and exhibits a mild enhancement at intermediate mu before becoming suppressed at large mu.