Evolution of Braneworld Kerr-Newman Naked Singularities

We study evolution of the braneworld Kerr--Newman (K-N) naked singularities, namely their mass $M$ , spin $a$, and tidal charge $b$ characterizing the role of the bulk space, due to matter in-falling from Keplerian accretion disk. We construct the evolution in two limiting cases applied to the tidal charge. In the first case we assume $b$ = const during the evolution, in the second one we assume that the dimensionless tidal charge $β\equiv b/M^2$ = const. For positive values of the tidal charge the evolution is equivalent to the case of the standard K-N naked singularity under accretion of electrically neutral matter. We demonstrate that counter-rotating accretion always converts a K-N naked singularity into an extreme K-N black hole and that the corotating accretion leads to variety of outcomes. The conversion to an extreme K-N black hole is possible for naked singularity with dimensionless tidal charge $β< 0.25$, and $β\in (0.25, 1)$ with sufficiently low spin. In other cases the accretion ends in a transcendental state. For $0.25 < β< 1$ this is a mining unstable K-N naked singularity enabling formally unlimited energy extraction from the naked singularity. In the case of $β> 1$, the corotating accretion creates unlimited torodial structure of mater orbiting the naked singularity. Both non-standard outcomes of the corotating accretion imply a transcendence of such naked singularity due to nonlinear gravitational effects.

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