Aspects of Nonlinear Effect on Black Hole Superradiance

TL;DR

This paper investigates how nonlinear interactions of boson fields affect black hole superradiance, revealing that such effects can saturate the instability and induce boson emission, with implications for photons, axions, and hidden photons.

Contribution

It introduces the impact of nonlinear effects on superradiance instability, showing potential saturation and emission phenomena not previously detailed.

Findings

Boson cloud growth can be saturated by nonlinear interactions.

Nonlinear effects induce boson emission during superradiance.

Revisits superradiance for photons, axions, and hidden photons.

Abstract

Under some conditions, light boson fields grow exponentially around a rotating black hole, called the superradiance instability. We discuss effects of nonlinear interactions of the boson on the instability. In particular, we focus on the effect of the particle production and show that the growth of the boson cloud may be saturated much before the black hole spin is extracted by the boson cloud, while the nonlinear interactions also induce the boson emission. For application, we revisit the superradiant instability of the standard model photon, axion and hidden photon.