Tunnelling black-hole radiation with $\phi^3$ self-interaction: one-loop computation for Rindler Killing horizons

TL;DR

This paper demonstrates that black hole radiation retains its thermal character at one-loop quantum correction level for a scalar field with self-interaction, confirming the robustness of Hawking radiation under perturbative quantum effects.

Contribution

It provides a perturbative quantum field theory analysis of black hole tunnelling with self-interactions, including renormalisation, showing the thermal nature persists at one-loop order.

Findings

Thermal form of tunnelling probability is preserved with one-loop corrections.

Renormalisation does not alter the exponential dependence on Hawking temperature.

Results are applicable to Minkowski and Unruh states near the horizon.

Abstract

Tunnelling processes through black hole horizons have recently been investigated in the framework of WKB theory discovering interesting interplay with the Hawking radiation. A more precise and general account of that phenomenon has been subsequently given within the framework of QFT in curved spacetime by two of the authors of the present paper. In particular, it has been shown that, in the limit of sharp localization on opposite sides of a Killing horizon, the quantum correlation functions of a scalar field appear to have thermal nature, and the tunnelling probability is proportional to $\exp\{-\beta_{Hawking} E\}$. This local result is valid in every spacetime including a local Killing horizon, no field equation is necessary, while a suitable choice for the quantum state is relevant. Indeed, the two point function has to verify a short-distance condition weaker than the Hadamard one. In this paper we consider a massive scalar quantum field with a $\phi^3$ self-interaction and we investigate the issue whether or not the black hole radiation can be handled at perturbative level, including the renormalisation contributions. We prove that, for the simplest model of the Killing horizon generated by the boost in Minkowski spacetime, and referring to Minkowski vacuum, the tunnelling probability in the limit of sharp localization on opposite sides of the horizon preserves the thermal form proportional to $\exp\{-\beta_H E\}$ even taking the one-loop renormalisation corrections into account. A similar result is expected to hold for the Unruh state in the Kruskal manifold, since that state is Hadamard and looks like Minkowski vacuum close to the horizon.