Delineating chiral separation effect in two-color dense QCD

Abstract

We study the chiral separation effect (CSE) in two-color and two-flavor QCD (QC2D) to delineate quasiparticle pictures in dense matter from low to high temperatures. Both massless and massive quarks are discussed. We particularly focus on the high density domain where diquarks form a color singlet condensate with the electric charge 1/3. The condensate breaks baryon number and U (1)A axial symmetry, and induces the electromagnetic Meissner effects. Within a quark quasiparticle picture, we compute the chiral separation conductivity at one-loop. We have checked that Nambu-Goldstone modes, which should appear in the improved vertices as required by the Ward-Takahashi identities, do not contribute to the chiral separation conductivity due to their longitudinal natures. In the static limit, the destructive interferences in the particle-hole channel, as in usual Meissner effects, suppress the conductivity (in chiral limit, to 1/3 of the normal phase's) This locally breaks the universality of the CSE coefficients, provided quasiparticle pictures are valid in the bulk matter.

Stiffening of matter in quark-hadron continuity

“…In fact, this is a crucial step to establish the quark-hadron continuity or the quarkyonic matter scenario, because the response in EoS as well as in the transports to changes in temperature is entirely different for hadronic and quark excitations [83]. In two-color QCD there is a hint from the lattice QCD for hadronic excitations at high density [84,85], although more data is needed to establish this idea.…”