Lifetime of scalar cloud formation around a rotating regular black hole

Does circumventing the curvature singularity of the Kerr black hole affect the timescale of the scalar cloud formation around it? By definition, the scalar cloud, forms a gravitational atom with hydrogen-like bound states, lying on the threshold of a massive scalar field's superradiant instability regime (timegrowing quasibound states) and beyond (time-decaying quasibound states). By taking a novel type of rotating hollow regular black hole proposed by Simpson and Visser which unlike its standard rivals has an asymptotically Minkowski core, we address this question. The metric has a minimal extension relative to the standard Kerr, originating from a single regularization parameter l, with length dimension. We show with the inclusion of the regularization length scale l into the Kerr spacetime, without affecting the standard superradiant instability regime, the timescale of scalar cloud formation gets shorter. Since the scalar cloud after its formation, via energy dissipation, can play the role of a continuum source for gravitational waves, such a reduction in the instability growth time improves the phenomenological detection prospects of new physics because the shorter the time, the more astrophysically important.

Automated summary

The study examines the impact of a novel rotating black hole on the timescale of scalar cloud formation, showing that including a regularization length scale l can shorten the formation time. This reduction in instability growth time improves the prospects for phenomenological detection of new physics.