Strong Cosmic Censorship in higher-dimensional Reissner-Nordström-de Sitter spacetime

Abstract

It was recently shown that Strong Cosmic Censorship might be violated for near-extremally-charged black holes in 4-dimensional de Sitter space under scalar perturbations. Here, we extend the study of neutral massless scalar perturbations in higher dimensions and discuss the dimensional influence on the validity of Strong Cosmic Censorship hypothesis. By giving an elaborate description of neutral massless scalar perturbations of Reissner-Nordström-de Sitter black holes in d = 4, 5 and 6 dimensions we conclude that Strong Cosmic Censorship is violated near extremality.

Superradiant instability of charged scalar fields in higher-dimensional Reissner-Nordström-de Sitter black holes

“…Intriguingly, we will show that the superradiant instability originates from a new family of QNMs which exists only in asymptotically de Sitter (dS) BHs and can be very well approximated by the QNMs of pure d−dimensional dS space. This novel family was very recently identified in asymptotically dS BHs for both scalar [54][55][56][57] and fermionic perturbations [58]. Finally, we will demonstrate that as the spacetime dimensions increase, the instability is amplified, occurs for a larger region of the subextremal parameter space and still satisfies the superradiant condition.…”

“…is the surface gravity of the cosmological horizon of pure d−dimensional dS space. The fundamental n = 0 BH dS QNMs reported in [54,55,57] are approximated, with high accuracy, by (14), while higher overtones have larger deformations to (14) and (15). Equivalent results have been obtained for fermionic perturbations on RNdS spacetime [58].…”

Cosmic censorship and the evolution of d -dimensional charged evaporating black holes

“…Recently, strong cosmic censorship of charged black holes in asymptotically de Sitter spacetime has attracted a lot of interest [22][23][24]. The situation in higher dimensions is not so straightforward [25]: it is indeed easier to violate strong cosmic censorship in higher dimensions, provided that the black holes are "large" (in the sense of large Λ/Λ max , where Λ is the cosmological constant, and Λ max is the value for which if Λ > Λ max , then the spacetime admits at most one horizon). If the black holes are small, then it becomes harder to violate the censorship.…”

“…Actually the situation is even more complicated: there exists range of Λ/Λ max for which the difficulty to violate strong cosmic censorship is not monotonic as one increases the dimensionality. For example, it could be that it is easiest to achieve this in 6-dimensions, but hardest to do so in 4-dimensions, and then followed by 5-dimensions (see Table 1 of [25]). In short, it is not easy to tell if under a given process, whether going to higher dimensions makes it easier to violate cosmic censorship (of either version).…”

Strong cosmic censorship conjecture in higher curvature gravity

“…In the absence of a general proof for strong cosmic censorship conjecture, such an analysis plays a very crucial role in order to test the conjecture, i.e., by looking for possible counterexamples. This approach have been used recently by several authors in order to test the validity of strong cosmic censorship conjecture conjecture for general relativity on various asymptotically de Sitter black hole spacetimes in four and higher dimensions [12][13][14][15][16][17][18][19][20][21][22][23]. The central result arising out of these analyses is the realization that the strong cosmic censorship conjecture is violated in the near extremal regime for non-rotating black holes, while for rotating black holes, the violation can be avoided.…”