Emergent Conformal Symmetry on Superfluid Vortices in Two-Color QCD and Pseudoreal Gauge Theories

Abstract

Two-color QCD provides a unique first-principles laboratory for strongly interacting matter at finite baryon density, where a diquark condensate realizes a baryonic superfluid. We investigate the internal physics of its quantized superfluid vortices in the chiral limit. We find that a vortex localizes an exact and normalizable $S^3\simeq SU(2)$ family of pion modes. Remarkably, the bulk Wess--Zumino--Witten (WZW) term induces a quantized WZW term for these modes, driving the vortex theory in the infrared to the $SU(2)_1$ WZW conformal field theory with central charge $c=1$. Thus a strongly coupled conformal theory emerges on a vortex in a nonconformal bulk theory. The mechanism extends to pseudoreal $Sp(2N)$ gauge theories, where the corresponding minimal vortex theory flows to $SU(2)_N$, with the level directly encoding the microscopic anomaly coefficient.