Quark-hadron continuity under rotation: Vortex continuity or boojum?

Quark-hadron continuity was proposed as a crossover between hadronic matter and quark matter without a phase transition, based on the matching of the symmetries and excitations in both phases. In the limit of a light strange-quark mass, it connects hyperon matter and the color-flavor-locked (CFL) phase exhibiting color superconductivity. Recently, it was proposed that this conjecture could be generalized in the presence of superfluid vortices penetrating both phases [arXiv:1803.05115], and it was suggested that one hadronic superfluid vortex in hyperon matter could be connected to one non-Abelian vortex (color magnetic flux tube) in the CFL phase. Here, we argue that their proposal is consistent only at large distances; instead, we show that three hadronic superfluid vortices must combine with three non-Abelian vortices with different colors with the total color magnetic fluxes canceled out, where the junction is called a colorful boojum. We rigorously prove this in both a macroscopic theory based on the Ginzburg-Landau description in which symmetry and excitations match (including vortex cores), and a microscopic theory in which the Aharonov-Bohm phases of quarks around vortices match.

Figure 1

A schematic diagram of connection of three $\mathrm{\Lambda }\mathrm{\Lambda }$ vortices in the hadronic phase with three different CFL vortices via a single $U(1)$ CFL vortex.