Black hole remnants may exist if Starobinsky inflation occurred

TL;DR

This paper explores the possibility that macroscopic zero temperature black hole remnants could exist if Starobinsky inflation took place, based on solutions to semiclassical backreaction equations involving quantum fields.

Contribution

It demonstrates that zero temperature black hole solutions are possible under certain conditions related to higher derivative terms in the gravitational Lagrangian, linked to Starobinsky inflation.

Findings

Zero temperature black hole solutions may exist with specific Lagrangian coefficients.

Quantum stress-energy tensor components depend mainly on local horizon geometry.

Conditions for black hole remnants are connected to early Universe inflation parameters.

Abstract

Zero temperature black hole solutions to the semiclassical backreaction equations are investigated. Evidence is provided that certain components of the stress-energy tensors for free quantum fields at the horizon only depend on the local geometry near the horizon. This allows the semiclassical backreaction equations to be solved near the horizon. It is found that macroscopic uncharged zero temperature black hole solutions to the equations may exist if the coefficient of one of the higher derivative terms in the gravitational Lagrangian is large enough and of the right sign for Starobinsky inflation to have occurred in the early Universe.