Hot Halos and Galactic Glasses

TL;DR

This paper explores the complex state space of non-extremal black hole bound states in supergravity, revealing stable configurations with glass-like properties and mapping their stability regions.

Contribution

It introduces a systematic analysis of black hole bound states, highlighting their stable 'halo' formations and drawing parallels with glassy systems in physics.

Findings

Existence of exponentially many stable black hole bound states

Identification of thermodynamically stable and metastable regions

Observation of glass-like relaxation timescales in black hole systems

Abstract

We initiate a systematic study of the state space of non-extremal, stationary black hole bound states in four-dimensional N = 2 supergravity. Specifically, we show that an exponential multitude of classically stable "halo" bound states can be formed between large finite temperature D4-D0 black hole cores and much smaller, arbitrarily charged black holes at the same temperature. We map out in full the regions of existence for thermodynamically stable and metastable bound states in terms of the core's charges and temperature, as well as the region of stability of the core itself. Several features of these systems, such as a macroscopic configurational entropy and exponential relaxation timescales, are similar to those of the extended family of glasses. We draw parallels between the two with a view toward understanding complex systems in fundamental physics.