Absorption of a Particle by a Rotating Black Hole: The Potential Barrier

Abstract

For a test particle approaching a rapidly rotating black hole we find a range of values of the particle's energy and angular momentum, on the order of 1\% or more of the corresponding values of the hole, such that three conditions are satisfied. 1) The particle can reach the horizon. 2) After absorption the new hole still has a horizon. 3) The area of the new hole is less than the area of the original one, in apparent violation of a theorem of Hawking. We offer support for the claim that the test particle approximation is the cause of the violation.