Are quantization rules for horizon areas universal?

TL;DR

This paper investigates the universality of horizon area quantization rules in black holes, demonstrating through examples that these rules do not generally hold in dynamical, non-stationary black hole spacetimes.

Contribution

The study provides evidence that horizon area quantization rules are not universal and do not apply to realistic, time-dependent black holes in general relativity.

Findings

Quantization rules fail in dynamical black hole spacetimes

Rules may only hold at isolated moments in time

Quantization is not universal across different black hole models

Abstract

Doubts have been expressed on the universality of holographic/string-inspired quantization rules for the horizon areas of stationary black holes or the products of their radii, already in simple 4-dimensional general relativity. Realistic black holes are not stationary but time-dependent. Using two examples of 4D general-relativistic spacetimes containing dynamical black holes for at least part of the time, it is shown that the quantization rules (even counting virtual horizons) cannot hold, except possibly at isolated instants of time, and do not seem to be universal.