Kinematics of evaporating black holes

TL;DR

This paper explores the kinematic properties of evaporating black holes within the semiclassical regime, demonstrating that their metrics can be described purely through Bondi charges without detailed quantum calculations.

Contribution

It introduces a purely kinematic description of black hole metrics in the semiclassical region using Bondi charges, bypassing complex quantum computations.

Findings

The metric in the semiclassical region is expressed through Bondi charges.

Quantum calculations are limited to radiation at infinity.

Ultraviolet ignorance does not affect the metric description.

Abstract

The correspondence principle and causality divide the spacetime of a macroscopic collapsing mass into three regions: classical, semiclassical, and ultraviolet. The semiclassical region covers the entire evolution of the black hole from the macroscopic to the microscopic scale if the latter is reached. It is shown that the metric in the semiclassical region is expressed purely kinematically through the Bondi charges. The only quantum calculation needed is the one of radiation at infinity. The ultraviolet ignorance of semiclassical theory is irrelevant. The metric with arbitrary Bondi charges is obtained and studied.