Time-reversal invariant vortex in topological superconductors and gravitational ${\mathbb{Z}}_2$ topology

Kazuki Yamamoto, Naoto Kan, Hidenori Fukaya

We study a time-reversal invariant vortex, namely a spin vortex, in helical superconductors by focusing on its emergent gravitational structure. The topology of the time-reversal i…