Bump of sound velocity in dense 2-color QCD

Abstract

We obtain the equation of state (EoS) and the sound velocity for 2-color QCD at low temperature and high density and find that in the superfluid phase, $c_s^2/c^2>1/3$, where $1/3$ is the value at the relativistic limit. Several independent Monte Carlo studies on 2-color QCD have been conducted intensively in recent years. These works have shown a clear evidence of phase transition between hadronic and superfluid phases. In our paper[1], we have investigated the EoS and sound velocity in both phases. Our result is consistent with chiral perturbation theory in a low $\mu$ regime of the superfluid phase including the Bose-Einstein condensed phase, and shows a peak of sound velocity in the high-density BCS phase. We also give detailed simulation results and a comment on the holography bound in this proceedings.

Comments: 9pages, 5figures, Proceedings of the 39th International Symposium on Lattice Field Theory,8th-13th August 2022, Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Germany. arXiv admin note: substantial text overlap with arXiv:2207.01253