Quark-Hadron Crossover with Vortices

Abstract

The quark-hadron crossover conjecture was proposed as a continuity between hadronic matter and quark matter with no phase transition. It is based on matching of symmetry and excitations in both the phases. It connects hyperon matter and color-flavor locked (CFL) phase of color superconductivity in the limit of light strange quark mass. We study generalization of this conjecture in the presence of topological vortices. We propose a picture where hadronic superfluid vortices in hyperon matter could be connected to non-Abelian vortices (color magnetic flux tubes) in the CFL phase during this crossover. We propose that three hadronic superfluid vortices must join together to three non-Abelian vortices with different color fluxes with the total color magnetic fluxes canceled out, where the junction is called a colorful boojum.

Aharonov-Bohm defects

“…Two-gap superconductors can be in fact regarded as such an example of a gap composed of fermion-fermion condensation with a non-trivial AB phase. A non-Abelian vortex in dense QCD [28][29][30][31][32][33] provides a non-trivial AB phase for charged particles [34] as well as a Z 3 AB phase for quarks [35][36][37][38], and so if (further) diquark condensation forms, it may give a fermion example of AB defects.…”

“…Non-Abelian vortices in supersymmetric gauge theory [9][10][11][12][13][14][15][16][17][18][19][20][21] exhibit AB effects [22][23][24] including non-Abelian generalization of AB effects [25], once a part of flavor symmetry is gauged [26]. In dense QCD which may be relevant for cores of neutron stars, a color magnetic flux tube in the 2SC phase exhibits AB effects for quarks [27], while a non-Abelian vortex (color magnetic flux tube) in the color-flavor locked phase [28][29][30][31][32][33] also exhibits (electromagnetic) AB effects for charged particles [34] as well as Z 3 (color) AB effects for quarks [35][36][37][38].…”

Confinement and moduli locking of Alice strings and monopoles

“…(color magnetic flux tube) in the color-flavor locked phase [25][26][27][28][29][30] exhibits (electromagnetic) AB effects for charged particles [31] as well as Z 3 (color) AB effects for quarks [32][33][34][35][36]. Non-Abelian Alice strings in two-flavor dense QCD exhibit nontrivial AB phases [37].…”

Topological confinement of vortices in two-flavor dense QCD

“…It is interesting to point out that in this definition, non-Abelian vortices in the CFL phase are already confined as they are [70,71].…”

“…A single non-Abelian vortex carries the so-called orientational moduli (collective coordinates) of the complex projective space CP 2 as Nambu-Goldstone modes trapped in its core [56,59,65,66] as well as a triplet of gapless Majorana fermions [67,68]. Recently, in the context of quark-hadron continuity, vortices penetrating through the CFL phase into hyperon matter have been extensively discussed [35,36,[69][70][71][72][73] (see also ref. [74] for the similar attempt in two-flavor setup).…”