A Status Report on the Phenomenology of Black Holes in Loop Quantum Gravity: Evaporation, Tunneling to White Holes, Dark Matter and Gravitational Waves

Abstract

The understanding of black holes in loop quantum gravity is becoming increasingly accurate. This review focuses on the possible experimental or observational consequences of the underlying spinfoam structure of space-time. It adresses both the aspects associated with the Hawking evaporation and the ones due to the possible existence of a bounce. Finally, consequences for dark matter and gravitational waves are considered. * Electronic address: Aurelien.Barrau@cern.ch † Electronic address: martineau@lpsc.in2p3.fr ‡ Electronic address: moulin@lpsc.in2p3.fr and conclude with prospective for gravitational waves.

Black-bounce to traversable wormhole

“…For a ∈ (0, 2m) the Carter-Penrose diagram is in some sense "as close as possible" to that for the maximally extended Kruskal-Szekeres version of Schwarzschild, except that the singularity is converted into a spacelike hypersurface representing a "bounce" into a future incarnation of the universe. This is qualitatively different from the picture where the collapsing regular black hole "bounces" back into our own universe [30][31][32][33][34][35][36][37][38][39][40][41][42], and is a scenario that deserves some attention in its own right. The specific model introduced above also has the very nice feature that it analytically interpolates between black holes and traversable wormholes in a particularly clear and tractable manner.…”

An Overview of Quasinormal Modes in Modified and Extended Gravity

“…with γ BI the Barbero-Immirzi parameter. Black holes are usually described in LQG through an isolated horizon puncturing a spin network [48] and the phenomenology is very rich, depending on the precise setting chosen [49]. We focus here on the model developed in [50], as this is the one leading to metric modifications outside the horizon, where a regular lattice with edges of lengths δ b and δ c is considered.…”

Resolving Spacetime Singularities within Asymptotic Safety

“…Conversely, any candidate for such a theory should explain the fate of these spacetime singularities. In Loop Quantum Gravity, black hole singularities may be removed by quantum geometry effects [4][5][6], also see [7] for a recent review. Similarly, the fuzzball proposal [8,9] provides a mechanism for obtaining regular black holes in the framework of string theory.…”

“…(7) and (10) where, by definition, the couplings become independent of k. Eq. (7) entails that at such a fixed point η N = −2. Substituting this value into eq.…”