Spin-Charge induced spontaneous scalarization of Kerr-Newman black holes

Abstract

We investigate the tachyonic instability of Kerr-Newman (KN) black holes in the Einstein-Maxwell-scalar (EMS) theory with a positive coupling parameter $\alpha$. This corresponds to exploring the onset of spontaneous scalarization for KN black holes. For this purpose, we use the hyperboloidal foliation method (HFM) to solve the linearized scalar equation numerically. We obtain a 3D graph [${\log }_{10}\alpha (a,Q)$] which indicates the onset surface for spontaneous scalarization of KN black holes in the EMS theory. We find that there is no lower bound on the rotational parameter $a$, but its upper bound is given by $M^2-Q^2\ge a^2$. Also, we confirm that the high rotation enhances spontaneous scalarization of KN black holes in the EMS theory.

21 pages, 6 figures, Version accepted for publication in PRD. arXiv admin note: text overlap with arXiv:2206.11587

References in corpus (3)

• Spontaneously scalarised Kerr black holes
• Black hole scalarisation from the breakdown of scale-invariance
• Scalar Fields in Black Hole Spacetimes