Berry Curvature and Spin-One Color Superconductivity

TL;DR

This paper investigates the topological properties of spin-one color superconductors, revealing how Berry curvature relates to gap structures and uncovering novel topological nodes and gapless excitations driven by internal quantum numbers.

Contribution

It generalizes the relation between Berry flux and topological nodes to systems with internal degrees of freedom like color, identifying new topological structures in color superconductors.

Findings

Identification of chirality-induced topological nodes in certain phases.

Discovery of gapless excitations with Berry monopole charges of ±3/2.

Extension of topological relations to systems with internal quantum numbers.

Abstract

We explore the interplay between Berry curvature and topological properties in single-flavor color superconductors, where quarks form spin-one Cooper pairs. By deriving a new relation, we connect the topological nodal structure of the gap function in momentum space to the (nonabelian) Berry flux associated with paired quarks. This generalizes the early work by Li and Haldane [Phys. Rev. Lett. 120, 067003 (2018)] to systems with additional internal quantum numbers, such as color. In the ultrarelativistic limit, we uncover rich topological structures driven by the interplay of spin, chirality, and color. Specifically, we identify chirality-induced topological nodes in the transverse (opposite chirality pairing) polar and A phases. In contrast, the color-spin-locking phase lacks these nodes due to a nontrivial color Berry flux, which in turn induces gapless excitations with total Berry monopole charges of $\pm 3/2-$differing from conventional Weyl fermions. Our findings can be potentially extended to other fermionic systems carrying additional internal degrees of freedom.