General Relativity and Quantum Cosmology
We present a new analytic model of a force-free electromagnetic jet launched from a disk-fed rotating black hole. The jet solution is force-free to first order in the black hole spin and is obtained through a systematic construction based…
We study the linear stability of nonrelativistic Proca stars under generic perturbations. Using a combination of analytic and numerical methods, we demonstrate that, as expected, the ground state is always mode-stable. Additionally, we…
Horizon-scale images of black holes provide a potential probe of fundamental physics, including tests of gravity and black hole hair. To assess the impact of scalar hair on accretion-flow imaging self-consistently, we construct an…
The detection of the gravitational waves produced after the coalescence of two neutron stars is greatly anticipated because it will be able to provide information about matter in extreme conditions, especially if the remnant turns out to go…
In this paper, we examine the physical consequences of a recently introduced black hole solution in bumblebee gravity [1]. The geometry is first presented and then reformulated through suitable coordinate adjustments, which make its global…
Ever since gravity-induced entanglement (GIE) experiments have been proposed as a witness of the quantum nature of gravity, more and more theories of classical gravity coupled to quantum matter have been shown to predict GIE, despite the…
Searching for a modified dispersion relation is one of the general relativity tests performed by the LIGO-Virgo-KAGRA collaboration with each new cumulative Gravitational Wave Transient Catalog (GWTC). It considers classes of theories that…
String theories naturally predict a negative, while observations on the exponential expansion of the present Universe require a positive value for the cosmological constant. Solution to resolve this discrepancy is known in the framework of…
We study gravitational waves induced by scalar primordial fluctuations in Gleyzes-Langlois-Piazza-Vernizzi (GLPV), beyond Horndeski, scalar-tensor theories. We uncover, at the level of the action, a new scalar-scalar-tensor interaction,…
The cosmological application of a dark viscous fluid in a spatially flat Friedmann-Robertson-Walker (FRW) universe with a modified logarithmic equation of state (EoS), being an analogue of the equation associated with the isotropic…
Seven years after the first direct detection of gravitational waves, from the collision of two black holes, the field of gravitational wave astronomy is firmly established. A first detection of continuous gravitational waves from…
Unlike electromagnetic telescopes, gravitational-wave (GW) detectors cannot produce pretty pictures, but we can convert GW signals into sound. I compute what the Universe actually sounds like by averaging over $\sim10^6$ synthetic compact…
A particular solution to the three-body problem is the circular Lagrange three-body system, where the masses move in circular orbits such that they always constitute an equilateral triangle. Such a system has been found to emit…
In Loop Quantum Gravity, the quantum action of the volume operator is crucial in understanding quantum dynamics. In this work, we implement a generalized numerical algorithm that can compute the quantum action of the volume operator on a…
We derive an asymptotic expansion for off-diagonal coherent-state matrix elements of non-polynomial operators in gauge theories admitting holomorphic coherent-state representations. The derivation combines stationary-phase analysis with an…
We present Q-Transform Amplitude Modulation (QTAM), a novel, fully invertible implementation of the Constant-Q Transform algorithm, designed to enable robust signal denoising and the disentanglement of overlapping transient events in…
Over the past decade, gravitational-wave astronomy has opened a new window onto the extreme states of matter inside compact stars. At some point during the inspiral of a binary system, each star starts to experience adiabatic tides,…
In this work, we investigate the relation between bound states and quasinormal modes within black hole perturbation theory in the context of spectral instability. Our analysis indicates that the reliability of such spectral mapping…
The theory of gravitational wave turbulence describes the long-term statistical behaviour of a set of weakly nonlinear interacting waves. In this paper, we aim to study aspects of gravitational turbulence within the framework of general…
The pulsar magnetosphere is a potential source of continuous gravitational waves due to the rapid charge-discharge process in short timescale, varying the electric-field energy density. We estimate the strain of the continuous gravitational…