Superradiant scattering by a black hole binary

Abstract

I present evidence of a novel guise of superradiance that arises in black hole binary spacetimes. Given the right initial conditions, a wave will be amplified as it scatters off the binary. This process, which extracts energy from the orbital motion, is driven by absorption across the horizons and is most pronounced when the individual black holes are not spinning. Focusing on real scalar fields, I demonstrate how modern effective field theory (EFT) techniques enable the computation of the superradiant amplification factor analytically when there exist large separations of scales. Although exploiting these hierarchies inevitably means that the amplification factor is always negligible (it is never larger than about one part in $10^{10}$) in the EFT's regime of validity, this work has interesting theoretical implications for our understanding of general relativity and lays the groundwork for future studies on superradiant phenomena in binary systems.

Version accepted for publication. 5 pages. A few extra details added, technical details moved to an appendix

References in corpus (27)

• An Effective Field Theory of Gravity for Extended Objects
• Instability of the massive Klein-Gordon field on the Kerr spacetime
• The Effective Field Theorist's Approach to Gravitational Dynamics
• Black holes in scalar-tensor gravity
• Superradiant Instability and Backreaction of Massive Vector Fields around Kerr Black Holes
• Massive spin-2 fields on black hole spacetimes: Instability of the Schwarzschild and Kerr solutions and bounds on the graviton mass
• Observation of superradiance in a vortex flow
• Superradiant instabilities in astrophysical systems
• Perturbations of slowly rotating black holes: massive vector fields in the Kerr metric
• The many faces of superradiance
• Gravitational radiative corrections from effective field theory
• Dissipative Effects in the Worldline Approach to Black Hole Dynamics
• The First Law of Binary Black Hole Mechanics in General Relativity and Post-Newtonian Theory
• Primordial black hole evolution in tensor-scalar cosmology
• Black holes and fundamental fields in Numerical Relativity: initial data construction and evolution of bound states
• Numerical simulations of single and binary black holes in scalar-tensor theories: circumventing the no-hair theorem
• Thermodynamics of binary black holes and neutron stars
• Late Inspiral and Merger of Binary Black Holes in Scalar-Tensor Theories of Gravity
• Nonlinear interactions between black holes and Proca fields
• Cosmic Black-Hole Hair Growth and Quasar OJ287
• Generalised superradiant scattering
• A Modern Approach to Superradiance
• Superradiance in stars
• Superradiance in rotating stars and pulsar-timing constraints on dark photons
• Superradiance without event horizons in General Relativity
• Effective field theory for black holes with induced scalar charges
• The physics of black hole binaries: geodesics, relaxation modes and energy extraction

Cited by in corpus (15)

• Prospects for Fundamental Physics with LISA
• Black hole merger simulations in wave dark matter environments
• The effect of wave dark matter on equal mass black hole mergers
• Growth of accretion driven scalar hair around Kerr black holes
• Black hole binaries and light fields: Gravitational molecules
• Spin-orbit effects for compact binaries in scalar-tensor gravity
• Evolution of black hole shadows from superradiance
• Moving black holes: energy extraction, absorption cross-section and the ring of fire
• Evolution of diffuse scalar clouds around binary black holes
• Accessing the axion via compact object binaries
• Energy Extraction From Non-Coalescing Black Hole Binaries
• Energy extraction in electrostatic extreme binary black holes
• Binary superradiance: a numerical study
• Scalar field dynamics around black holes: superradiant instabilities and binary evolution
• The Gravity of Classical Fields: And Its Effect on the Dynamics of Gravitational Systems