Emerging Hawking-like Radiation from Gravitational Bremsstrahlung Beyond the Planck Scale

TL;DR

This paper explores how high-energy gravitational scattering beyond the Planck scale produces a Hawking-like radiation spectrum with sub-Planckian energies, revealing new insights into quantum gravity effects.

Contribution

It introduces a novel description of graviton bremsstrahlung at trans-Planckian energies using helicity phases, linking quantum scattering with Hawking-like radiation features.

Findings

Spectrum shows sub-Planckian energies of order M_P^2/E

Identifies a suppressed fragmentation region in the spectrum

Findings align with recent classical estimates of gravitational radiation

Abstract

We argue that, as a consequence of the graviton's spin-2, its bremsstrahlung in trans-planckian-energy ($E\gg M_P$) gravitational scattering at small deflection angle can be nicely expressed in terms of helicity-transformation phases and their transfer within the scattering process. The resulting spectrum exhibits deeply sub-planckian characteristic energies of order $M_P^2/E \ll M_P$ (reminiscent of Hawking radiation), a suppressed fragmentation region, and a reduced rapidity plateau, in broad agreement with recent classical estimates.