Corrigendum to “The instability spectra of near-extremal Reissner-Nordström-de Sitter black holes” [Phys. Lett. B 786 (2018) 217–222]

Physics Letters B 796 (2019) 256

Contents lists available at ScienceDirect

Physics Letters B www.elsevier.com/locate/physletb

Corrigendum

Corrigendum to “The instability spectra of near-extremal Reissner-Nordström-de Sitter black holes” [Phys. Lett. B 786 (2018) 217–222] Shahar Hod a,b,∗ a b

The Ruppin Academic Center, Emeq Hefer 40250, Israel The Hadassah Institute, Jerusalem 91010, Israel

a r t i c l e

i n f o

a b s t r a c t

Article history: Available online 29 March 2019 Editor: M. Cvetiˇc

We point out that the instability spectrum of the near-extremal Reissner-Nordström-de Sitter black holes discussed in Hod (2018) [1] lies outside the superradiant regime of the system. © 2018 The Author(s). Published by Elsevier B.V. All rights reserved.

1. Introduction In a recently published paper [1] we have explicitly shown that near-extremal Reissner-Nordström-de Sitter black holes may become unstable to perturbations of charged massive scalar fields. In particular, we have identified two families of complex resonant modes whose real parts are given by the simple relation ±

ωR =

qQ r+

−

qQ 1 − 2( Q /r+ )2



 1±

1+

 μr 2  +

qQ

1 − 2( Q /r+ )2





2 r+ ) . · κ+ + O (κ+

(1)

Here {r+ , rc } are the horizon radii of the non-asymptotically flat black-hole spacetime, Q is the electric charge of the black hole, and {μ, q} are the proper mass and electric charge of the scalar field. It was pointed out in [1] that the minus family of resonant modes is characterized by the inequality ωR− > q Q /r+ and it therefore lies outside the superradiant regime q Q /rc < ω < q Q /r+ of the system. In addition, it was claimed in [1] that the plus modes should be regarded as superradiant modes with the property ωR+ < q Q /r+ . However, it should be pointed out that this family of resonant modes is also characterized by the inequality ωR+ < q Q /rc [2]. Thus, these resonant modes should not be regarded as superradiant modes of the composed system. Acknowledgements This research is supported by the Carmel Science Foundation. I would like to thank Yael Oren, Arbel M. Ongo, Ayelet B. Lata, and Alona B. Tea for helpful discussions. References [1] S. Hod, Phys. Lett. B 786 (2018) 217. [2] I would like to thank Professor Ran Li for pointing out the fact that the resonant frequency

*

DOI of original article: https://doi.org/10.1016/j.physletb.2018.09.039. Correspondence to: The Ruppin Academic Center, Emeq Hefer 40250, Israel. E-mail address: [email protected].

https://doi.org/10.1016/j.physletb.2018.12.024 0370-2693/© 2018 The Author(s). Published by Elsevier B.V. All rights reserved.

ωR+ is characterized by the inequality ωR+ < q Q /rc .