Related papers: High-frequency gravitational wave transients from …
Slow first-order phase transitions generate large inhomogeneities that can lead to the formation of primordial black holes (PBHs). We show that the gravitational wave (GW) spectrum then consists of a primary component sourced by bubble…
Ultralight scalar fields around spinning black holes can trigger superradiant instabilities, forming a long-lived bosonic condensate outside the horizon. We use numerical solutions of the perturbed field equations and astrophysical models…
Ultralight bosons around comparable-mass binaries can form gravitationally bound states analogous to molecules once the binary separation decreases below the boson's Bohr radius, with the inner region co-moving with the binary. We simulate…
We find the inferred properties of the putative gravitational wave background in the second data release of the European Pulsar Timing Array to be in better agreement with theoretical expectations under the improved noise model. In…
Binary Systems are the most studied sources of gravitational waves. The mechanisms of emission and the behavior of the orbital parameters are well known and can be written in analytic form in several cases. Besides, the strongest indication…
In this brief article, we pursue the systematic investigation of possible gravitational wave sources in the gigahertz band. We focus on hyperbolic encounters of light black holes and evaluate precisely the expected signal when accounting…
We show that for detections of gravitational-wave transients, constraints can be given on physical parameters of the source without using any specific astrophysical models. Relying only on fundamental principles of general relativity, we…
Gravitational waves at kilohertz and higher frequencies offer a unique probe of the early Universe at temperatures well beyond the reach of the cosmic microwave background, corresponding to energy scales $\gtrsim 10^9$GeV. Existing detector…
Superradiance clouds of kinetically-mixed dark photons around spinning black holes can produce observable multi-messenger electromagnetic and gravitational wave signals. The cloud generates electric fields of up to a Teravolt-per-meter,…
Gravitational waves with frequencies below 1~nHz are notoriously difficult to detect. With periods exceeding current experimental lifetimes, they induce slow drifts in observables rather than periodic correlations. Observables with…
In this paper, we investigate periodic bound orbits and gravitational wave (GW) emission in the Schwarzschild-Bertotti-Robinson (Schwarzschild-BR) spacetime-an exact electrovacuum solution describing a static black hole (BH) immersed in a…
We examine the main properties of gravitational waves (GWs) emitted by transient hyperbolic encounters of black holes. We begin by building the set of basic variables most relevant to setting our problem. After exposing the ranges of masses…
We give a detailed treatment of electromagnetic signals generated by gravitational waves (GWs) in resonant cavity experiments. Our investigation corrects and builds upon previous studies by carefully accounting for the gauge dependence of…
We perform a comprehensive study of gravitational waves in the context of the higher-order quadratic scalar curvature gravity, which encompasses the ordinary Einstein-Hilbert term in the action plus an $R^{2}$ contribution and a term of the…
We show that the nonperturbative decay of ultralight scalars into Abelian gauge bosons, recently proposed as a possible solution to the Hubble tension, produces a stochastic background of gravitational waves which is constrained by the…
We study the phenomenology of string bosenova explosions in vector superradiance clouds around spinning black holes, focusing on the observable consequences in gravitational wave detectors and accelerometers. During the growth of the…
Particles in a yet unexplored dark sector with sufficiently large mass and small gauge coupling may form purely gravitational atoms (quantum gravitational bound states) with a rich phenomenology. In particular, we investigate the…
We investigate gravitational-wave backgrounds (GWBs) of primordial origin that would manifest only at ultra-high frequencies, from kilohertz to 100 gigahertz, and leave no signal at either LIGO, Einstein Telescope, Cosmic Explorer, LISA, or…
Gravitational wave detectors are formidable tools to explore strong-field gravity, especially black holes and neutron stars. These compact objects are extraordinarily efficient at producing electromagnetic and gravitational radiation. As…
Motivated by the new heavy dark matter production mechanism from cosmic phase transition, we propose a novel mechanism for the generation of microscopic gravitational waves (GWs) during cosmological first-order phase transitions arising…