# Two roads to antispacetime in polar distorted B phase: Kibble wall and half-quantum vortex

## TL;DR

This paper explores how emergent antispacetime in superfluid helium-3 can be realized through two different defect configurations, providing insights into discrete symmetry formation from continuous symmetries.

## Contribution

It introduces two distinct pathways to achieve antispacetime in superfluid helium-3, linking defect structures to symmetry emergence.

## Key findings

- Antispacetime can be realized via two routes: around Alice strings or through Kibble walls.
- The study suggests a scenario for discrete parity symmetry formation from continuous symmetries.
- Experimental analogs of emergent gravity and antispacetime are discussed.

## Abstract

We consider the emergent tetrad gravity and the analog of antispacetime realized in the recent experiments ( J.T. Makinen, et al., Nat. Comm. 10, 237 (2019)) on the composite defects in superfluid $^3$He: the Kibble walls bounded by strings (the half quantum vortices). The antispacetime can be reached in two different ways: by the "safe" route around the Alice string or by dangerous route across the Kibble wall. This consideration also suggests the scenario of the formation of the discrete symmetry -- the parity $P$ in Dirac equations -- from the continuous symmetry existing on the more fundamental level.