Thermal quarks and gluon propagators in two-color dense QCD

Toru Kojo,Daiki Suenaga

doi:10.1103/physrevd.103.094008

Abstract

We study Landau gauge gluon propagators in two-color QCD at finite quark chemical potential ($\mu_q$) and temperature ($T$). We include medium polarization effects at one-loop by quarks into massive gluon propagators, and compared the analytic results with the available lattice data. We particularly focus on the high density phase of color-singlet diquark condensates whose critical temperature is $\sim 100$ MeV with weak dependence on $\mu_q$. At zero temperature the color singlet condensates protect the IR limit of electric and magnetic gluon propagators from the medium screening effects. At finite temperature, this behavior remains true for the magnetic sector, but the electric screening mass should be generated by thermal, and hence gapless, particles which are unbound from the diquark condensates. Treating thermal excitations as quasi-quarks, we found that the electric screening develops too fast compared to the lattice results. Beyond the critical temperature for diquark condensates the analytic results are consistent with the lattice results.

Highlights

There have been growing interests on the dynamics at baryon density ranging from ∼5n0 to ∼40n0 in the context of neutron star physics [1,2,3,4,5]
We focus on the high density phase of color-singlet diquark condensates whose critical temperature is ∼100 MeV with a weak dependence on μq
The color singlet condensates protect the IR limit of electric and magnetic gluon propagators from the medium screening effects. This behavior remains true for the magnetic sector, but the electric screening mass should be generated by thermal, and gapless, particles which are unbound from the diquark condensates

Summary

INTRODUCTION

There have been growing interests on the dynamics at baryon density ranging from ∼5n0 to ∼40n0 in the context of neutron star physics [1,2,3,4,5]. Including the gluon mass tempers the impact of medium polarization effects both in electric and magnetic propagators, while the presence of diquark gaps substantially weakens the electric corrections. These two effects seem necessary to reproduce the lattice and not to spoil the systematics of computations. This liberation of colors is driven by entropic effects that compensate the Boltzmann factor, like in the case of a Hagedorn gas [78,79,80,81] In this picture of deconfinement, the critical temperature decreases as density increases, as more phase space is available for low energy excitations, and the entropy increases (provided that ΔT is not sensitive to density or μq).

ANALYTIC RESULTS

COMPARISON WITH THE LATTICE DATA

SUMMARY AND DISCUSSION