Self-dual Black Holes in LQG: Theory and Phenomenology

TL;DR

This paper explores the self-dual properties of loop quantum black holes, their stability, potential role as dark matter, and implications for high-energy cosmic-ray emissions, linking quantum gravity with observable astrophysical phenomena.

Contribution

It introduces the self-dual metric in LQG black holes, analyzes their stability, and proposes their possible contribution to dark matter and cosmic-ray production.

Findings

Self-dual LQBH metric is invariant under r <-> a0/r exchange.

Small LQBHs are stable and could be dark matter candidates.

Ultra-light LQBHs could produce observable high-energy cosmic rays.

Abstract

In this paper we have recalled the semiclassical metric obtained from a classical analysis of the loop quantum black hole (LQBH). We show that the regular Reissner-Nordstrom-like metric is self-dual in the sense of T-duality: the form of the metric obtained in Loop quantum Gravity (LQG) is invariant under the exchange "r <-> a0/r" where "a0" is proportional to the minimum area in LQG and "r" is the standard Schwarzschild radial coordinate at asymptotic infinity. Of particular interest, the symmetry imposes that if an observer at "r" close to infinity sees a black hole of mass "m" an observer in the other asymptotic infinity beyond the horizon (at "r" close to "0") sees a dual mass "mp/m" ("mp" is the Planck mass). We then show that small LQBH are stable and could be a component of dark matter. Ultra-light LQBHs created shortly after the Big Bang would now have a mass of approximately "10^(-5) mp" and emit radiation with a typical energy of about 10^(13) - 10^(14) eV but they would also emit cosmic rays of much higher energies, albeit few of them. If these small LQBHs form a majority of the dark matter of the Milky Way's Halo, the production rate of ultra-high-energy-cosmic-rays (UHECR) by these ultra light black holes would be compatible with the observed rate of the Auger detector.