Speaker
Description
Dense QCD matter is expected to exhibit color-superconducting phases, such as the color-flavor-locked (CFL) phase. In the CFL phase, the color gauge symmetry is Higgsed, and the global $U(1)_B$ baryon-number symmetry is spontaneously broken. An interesting observation is that a hadronic superfluid phase at intermediate densities realizes the same pattern of global symmetry breaking. This motivates the conjecture of quark–hadron continuity, namely that the hadronic superfluid and CFL phases may be smoothly connected without a thermodynamic phase transition. Because direct lattice simulations of dense QCD suffer from the sign problem, gauge–Higgs models with analogous symmetry structures provide useful laboratories for studying this question.
In this work, we study a two-color, two-flavor $SU(2)$ gauge–Higgs model with a color–flavor-locking potential. The Higgs field carries both color and flavor indices, and the potential favors a color–flavor-locked configuration. This model possesses a global $U(1)$ symmetry analogous to the baryon-number symmetry in QCD, and its $U(1)$-broken phase contains both confinement and Higgs(CFL) regimes. We investigate the phase diagram of this model and Higgs–confinement continuity in the $U(1)$-broken phase. This study serves as a tractable lattice approach to quark–hadron continuity in QCD through the corresponding Higgs–confinement continuity in a gauge–Higgs model.