Micro Black Holes and the Democratic Transition

TL;DR

This paper proposes a classical process during microscopic black hole evaporation that leads to a democratic sharing of the black hole among multiple branes, resolving a unitarity and species differentiation puzzle.

Contribution

It introduces a new classical time-scale during black hole evaporation that causes black holes to become democratic across species in models with extra dimensions.

Findings

Black holes evolve to a democratic state by accreting neighboring branes.

The process occurs in models with large extra dimensions and multiple branes.

All species end up sharing the same Hawking temperature and black hole.

Abstract

Unitarity implies that the evaporation of microscopic quasi-classical black holes cannot be universal in different particle species. This creates a puzzle, since it conflicts with the thermal nature of quasi-classical black holes, according to which all the species should see the same horizon and be produced with the same Hawking temperatures. We resolve this puzzle by showing that for the microscopic black holes, on top the usual quantum evaporation time, there is a new time-scale which characterizes a purely classical process during which the black hole looses the ability to differentiate among the species, and becomes democratic. We demonstrate this phenomenon in a well-understood framework of large extra dimensions, with a number of parallel branes. An initially non-democratic black hole is the one localized on one of the branes, with its high-dimensional Schwarzschild radius being much shorter than the interbrane distance. Such a black hole seemingly cannot evaporate into the species localized on the other branes, that are beyond its reach. We demonstrate that in reality the system evolves classically in time, in such a way that the black hole accretes the neighboring branes. The end result is a completely democratic static configuration, in which all the branes share the same black hole, and all the species are produced with the same Hawking temperature. Thus, just like their macroscopic counterparts, the microscopic black holes are universal bridges to the hidden sector physics.