Effective spacetime and Hawking radiation from moving domain wall in thin film of 3He-A

TL;DR

This paper explores how a moving topological soliton in superfluid 3He-A creates an effective spacetime with horizons, analyzing the potential for Hawking radiation and the behavior of quasiparticles near these horizons.

Contribution

It introduces a model of effective spacetime in superfluid 3He-A with moving solitons creating horizons, and discusses the implications for Hawking radiation in this system.

Findings

Effective horizons are formed by moving solitons in 3He-A.

Quasiparticles experience an effective gravitational field with horizons.

Nonrelativistic corrections prevent quasiparticles from escaping at singularities.

Abstract

An event horizon for "relativistic" fermionic quasiparticles can be constructed in a thin film of superfluid 3He-A. The quasiparticles see an effective "gravitational" field which is induced by a topological soliton of the order parameter. Within the soliton the "speed of light" crosses zero and changes sign. When the soliton moves, two planar event horizons (black hole and white hole) appear, with a curvature singularity between them. Aside from the singularity, the effective spacetime is incomplete at future and past boundaries, but the quasiparticles cannot escape there because the nonrelativistic corrections become important as the blueshift grows, yielding "superluminal" trajectories. The question of Hawking radiation from the moving soliton is discussed but not resolved.