Revisiting collisional Penrose processes in term of escape probabilities for spinning particles

TL;DR

This paper investigates how the escape probability of spinning particles emitted from Kerr black holes varies with particle spin and black hole parameters, revealing complex dependencies that influence energy extraction efficiency in collisional Penrose processes.

Contribution

It provides a detailed analysis of escape probabilities for spinning particles in Kerr black holes and their relation to energy extraction efficiency, considering both extreme and non-extreme cases.

Findings

Escape probability increases with particle spin near the extreme Kerr black hole.

Escape probability decreases near the horizon but increases far from it as spin increases.

Energy extraction efficiency correlates with escape probability, varying between extreme and non-extreme Kerr black holes.

Abstract

We first study the escape probability of the spinning particle emitted from the Kerr black hole and find that the escape probability increases with the spin of the particle around the extreme Kerr black hole; in contrast, the escape probability decreases at the position near the horizon but increases at the position far away from the horizon with the increasing spin of the particle. We then probe the relation between the escape probabilities and the energy extraction efficiencies of collisional Penrose processes for the particles with varying spin. For the extreme Kerr black hole, the efficiency increases with the escape probability; for the non-extreme Kerr black hole, the near-horizon-efficiency decreases with the escape probability whilst the efficiency may increase with the escape probability in the ergosphere. In the event horizon limit, we also find that the average escape probability of the spinning particle produced in the collisional Penrose process decreases with the rotation parameter of the Kerr black hole.