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

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.

11 pages, 22 eps figures, to be published in special issue of EPJA. v2: expanded introduction with additional references; improved analysis of Polyakov loop and static quark potential leading to some changes in results and conclusions; some changes to discussion and presentation. Accepted for publication