Black Hole Radiation with Modified Dispersion Relation in Tunneling Paradigm: Static Frame

TL;DR

This paper investigates how modified dispersion relations at high energies affect Hawking radiation and black hole entropy, finding that the thermal spectrum remains robust with suppressed corrections, and the leading entropy term depends on the dispersion modifications.

Contribution

It introduces a Hamilton-Jacobi method analysis of dispersive field models in a static black hole frame, revealing the robustness of Hawking radiation spectrum against high-energy modifications.

Findings

Corrections to Hawking temperature are suppressed by Planck mass.

Leading entropy term depends on dispersion relation modifications.

Black hole luminosities are computed using geometric optics approximation.

Abstract

Due to the exponential high gravitational red shift near the event horizon of a black hole, it might appears that the Hawking radiation would be highly sensitive to some unknown high energy physics. To study possible deviations from the Hawking's prediction, the dispersive field theory models have been proposed, following the Unruh's hydrodynamic analogue of a black hole radiation. In the dispersive field theory models, the dispersion relations of matter fields are modified at high energies, which leads to modifications of equations of motion. In this paper, we use the Hamilton-Jacobi method to investigate the dispersive field theory models. The preferred frame is the static frame of the black hole. The dispersion relation adopted agrees with the relativistic one at low energies but is modified near the Planck mass $m_{p}$. We calculate the corrections to the Hawking temperature for massive and charged particles to $\mathcal{O}\left(m_{p}^{-2}\right) $ and massless and neutral particles to all orders. Our results suggest that the thermal spectrum of radiations near horizon is robust, e.g. corrections to the Hawking temperature are suppressed by $m_{p}$. After the spectrum of radiations near the horizon is obtained, we use the brick wall model to compute the thermal entropy of a massless scalar field near the horizon of a 4D spherically symmetric black hole. We find that the leading term of the entropy depends on how the dispersion relations of matter fields are modified, while the subleading logarithmic term does not. Finally, the luminosities of black holes are computed by using the geometric optics approximation.