Extremal Black Holes in Cosmology from Colliding Light Beams

TL;DR

This paper explores how extremal Reissner-Nordstrom black holes can form from colliding electromagnetic waves, suggesting a new way to understand cosmological black holes generated by light.

Contribution

It demonstrates that extremal black holes can originate from pure electromagnetic wave collisions, linking colliding wave solutions to black hole formation in cosmology.

Findings

Pure electromagnetic wave collisions can produce near horizon geometries of extremal black holes.

Quantum restrictions limit the horizon radii of such black holes to above 10^8 meters.

Impulsive gravitational waves generated in the process could aid in detecting black holes formed from light.

Abstract

From the duality between the interaction region of colliding waves and black holes (BHs) it is known that certain BH solutions can be obtained from colliding gravity coupled electromagnetic (em) waves. In the limit of vanishing gravity waves, we show that extremal Reissner-Nordstrom (RN) BH can form. We show also that direct collision of pure em waves creates the near horizon geometry (NHG) of the same BH, supporting our point. Due to the quantum restrictions such BHs can have horizon radii in the range $R>10^{8}m$. If such BHs from pure light do exist this may open a new frontier in our understanding of cosmological BHs at large. The generation of impulsive gravitational waves in the process may be instrumental in the detection of a BH created from pure light.