Self-organized criticality in boson clouds around black holes

TL;DR

This paper models boson clouds around black holes using cellular automata and demonstrates that their dynamics exhibit self-organized criticality, providing insights into black hole spin-down and cloud collapse phenomena.

Contribution

It introduces a simple cellular automaton model to simulate the unstable behavior of boson clouds, revealing self-organized criticality in their evolution.

Findings

Cellular automaton model exhibits self-organized criticality.

Boson cloud evolution linked to self-organized criticality on the Regge plane.

Collapse events resemble Bosenova phenomena.

Abstract

Boson clouds around black holes exhibit interesting physical phenomena through the Penrose process of superradiance, leading to black hole spin-down. Axionic clouds are of particular interest, since the axion Compton wavelength could be comparable to the Schwarzschild radius, leading to the formation of "gravitational atoms" with a black hole nucleus. These clouds collapse under certain conditions, leading to a "Bosenova". We model the dynamics of such unstable boson clouds by a simple cellular automaton and show that it exhibits self-organized criticality. Our results suggest that the evolution through the black hole Regge plane is due to self-organized criticality.