Abstract The Laser Interferometer Space Antenna (LISA) has the potential to reveal wonders
about the fundamental theory of nature at play in the extreme gravity regime, where the …

In this paper, which is of programmatic rather than quantitative nature, we aim to further
delineate and sharpen the future potential of the LISA mission in the area of fundamental …

It was recently shown that a scalar field suitably coupled to the Gauss-Bonnet invariant G
can undergo a spin-induced linear tachyonic instability near a Kerr black hole. This …

Massive vector fields feature in several areas of particle physics, eg, as carriers of weak
interactions, dark matter candidates, or an effective description of photons in a plasma. Here …

We study extreme mass-ratio binary systems in which a stellar mass compact object spirals
into a supermassive black hole surrounded by a scalar cloud. Scalar clouds can form …

We compute the quasi-bound state spectra of ultralight scalar and vector fields around
rotating black holes. These spectra are determined by the gravitational fine structure …

We study the imprints of new ultralight particles on the gravitational-wave signals emitted by
binary black holes. Superradiant instabilities may create large clouds of scalar or vector …

We study the electrodynamics of a kinetically mixed dark photon cloud that forms through
superradiance around a spinning black hole, and design strategies to search for the …

We derive the quadratic action for the physical degrees of freedom of massless spin-0, spin-
1, and spin-2 perturbations on a Schwarzschild-(A) dS background in arbitrary dimensions …

Because of coherent superradiant amplification, massive bosonic fields can trigger an
instability in spinning black holes, tap** their energy and angular momentum and forming …