We provide a theoretical model of F (R) gravity in which it is possible to describe in a unified
way inflation, an early and a late dark energy era, in the presence of a light axion particle …

We perform an extensive analysis of the statistics of axion masses and interactions in
compactifications of type IIB string theory, and we show that black hole superradiance …

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 …

Clouds of ultralight bosons—such as axions—can form around a rapidly spinning black
hole, if the black hole radius is comparable to the bosons' wavelength. The cloud rapidly …

Wormholes are hypothetical topologically-non-trivial structures of spacetime. From the
theoretical point of view, the possibility of their existence is challenging but cannot be ruled …

Ultralight bosons are well-motivated particles from various physical and cosmological
theories and can be spontaneously produced during the superradiant process, forming a …

Black Hole measurements have grown significantly in the new age of gravitation wave
astronomy from LIGO observations of binary black hole mergers. As yet unobserved massive …

A sensitive test for whether a black hole is a wormhole, using astronomical observations,
would be to look for perturbations in the orbit of a pulsar around the black hole, caused by a …

We propose to use pulsar–black hole binaries as a probe of gravitational collider physics.
Induced by the gravitation of the pulsar, the atomic transitions of the boson cloud around the …

A rotating black hole can be clouded by light bosons via superradiance and thus acquire an
atom-like structure. If such a gravitational atom system is accompanied by a pulsar, the …