Super-Penrose process for extremal charged white holes

TL;DR

This paper investigates the super-Penrose process near extremal charged white holes, showing it is generally impossible with finite angular momenta but possible if angular momenta are unbounded, contrasting with black hole scenarios.

Contribution

It demonstrates that super-Penrose processes are not feasible with finite angular momenta near white holes, highlighting a key difference from black hole cases.

Findings

Super-Penrose process is impossible with finite angular momenta near white holes.

Unbounded angular momenta enable the super-Penrose process for white holes.

White hole scenarios differ fundamentally from black hole cases regarding energy extraction.

Abstract

We consider collision of two particles 1 and 2 near the horizon of the extremal Reissner-Nordstr\"{o}m (RN) black hole that produce two other particles 3 and 4. There exists such a scenario that both new particles fall in a black hole. One of them emerges from the white hole horizon in the asymptotically flat region, the other one oscillates between turning points. However, the unbounded energies $E$ at infinity (super-Penrose process - SPP) turn out to be impossible for any finite angular momenta $L_{3.4}$. In this sense, the situation for such a white hole scenarios is opposite to the black hole ones, where the SPP is found earlier to be possible for the RN metric even for all $L_{i}=0$. However, if $L_{3,4}$ themselves are unbounded, the SPP does exist for white holes.