Semiclassical ultraextremal horizons

TL;DR

This paper investigates how quantum massive fields affect ultraextremal horizons, demonstrating that such horizons shift position but remain as self-consistent solutions within semiclassical gravity.

Contribution

It shows that quantum backreaction causes ultraextremal horizons to move but still exist as consistent solutions in semiclassical field equations.

Findings

Ultraextremal horizons shift position due to quantum backreaction.

Self-consistent solutions of semiclassical equations still include ultraextremal horizons.

The metric's asymptotics remain unchanged after the horizon shift.

Abstract

We examine backreaction of quantum massive fields on multiply-degenerate (ultraextremal) horizons. It is shown that, under influence of the quantum backreaction, the horizon of such a kind moves to a new position, near which the metric does not change its asymptotics, so the ultraextremal black holes and cosmological spacetimes do exist as self-consistent solutions of the semiclassical field equations.