Black/White hole radiation from dispersive theories

TL;DR

This paper investigates how dispersive theories affect black and white hole radiation, revealing that dispersion modifies spectral fluxes and introduces a critical frequency, with implications for black hole physics and Bose-Einstein condensates.

Contribution

It provides a numerical analysis of dispersive effects on black hole radiation spectra, including deviations from the standard flux and the role of asymptotic background properties.

Findings

Fluxes are governed by a 3x3 Bogoliubov transformation.

A critical frequency determines the cutoff for radiation.

Low-frequency flux remains nearly thermal but with altered temperature.

Abstract

We study the fluxes emitted by black holes when using dispersive field theories. We work with stationary one dimensional backgrounds which are asymptotically flat on both sides of the horizon. The asymptotic fluxes are governed by a 3x3 Bogoliubov transformation. The fluxes emitted by the corresponding white holes are regular and governed by the inverse transformation. We numerically compute the spectral properties of these fluxes for both sub- and superluminal quartic dispersion. The leading deviations with respect to the dispersionless flux are computed and shown to be governed by a critical frequency above which there is no radiation. Unlike the UV scale governing dispersion, its value critically depends on the asymptotic properties of the background. We also study the flux outside the robust regime. In particular we show that its low frequency part remains almost thermal but with a temperature which significantly differs from the standard one. Application to four dimensional black holes and Bose-Einstein condensates are in preparation.