Hawking radiation and secularly growing loop corrections

TL;DR

This paper investigates the behavior of the energy momentum tensor during black hole formation, revealing that two-loop quantum corrections grow secularly, indicating potential limitations of perturbation theory in describing Hawking radiation.

Contribution

It introduces a two-loop calculation of quantum corrections during black hole formation, demonstrating secular growth that challenges the validity of perturbative approaches.

Findings

Tree-level energy flux shows Hawking-like thermal behavior.

Two-loop corrections exhibit secular growth over time.

Perturbation theory may break down due to secular effects.

Abstract

We study the expectation value of the energy momentum tensor during thin shell collapse for a massive, real, scalar field theory. At tree-level, we find thermal, Hawking-type, behaviour for the energy flux. Using the Schwinger-Keldysh technique, we calculate two-loop corrections to the tree-level correlation functions and show that they exhibit secular growth, suggesting the breakdown of the perturbation theory.