General Relativity and Quantum Cosmology
Next-generation gravitational-wave detectors will require significant improvements in current theoretical waveform models, particularly in the case of asymmetric-mass binaries. Here we provide one such improvement by calculating fully…
It is commonly believed that a quantum field theory of General Relativity requires a non-perturbative formulation. In addition, the background independence of classical General Relativity supplies a physical selection criterion for suitable…
We investigate the thermodynamic structure of charged AdS black holes in ModMax nonlinear electrodynamics coupled to dRGT-like massive gravity, incorporating Sharma--Mittal entropy corrections. The thermodynamic geometry is analyzed using…
In this article, we study the cosmic evolution of a generalized dilatonic ghost condensate field as a dark energy candidate, formulated from a Lagrangian density with two dominant kinetic terms; one linear and one of arbitrary integer $n>2$…
We settle the global nonlinear stability problem for the family of Kerr black holes in the full subextremal range: spacetimes evolving from initial data close to those of a subextremal Kerr black hole as solutions of the Einstein vacuum…
The primary challenge for space-borne gravitational wave (GW) detectors lies in extracting the weak GW signal from instrumental noise that exceeds the signal level by many orders of magnitude. Time-delay interferometry (TDI) addresses this…
Axion clouds around rotating black holes form gravitational atoms whose tidal transitions can radiate gravitational waves in binaries. For strongly coupled Bohr crossings, transition radiation is governed by the outgoing two-level…
A line-of-sight acceleration (LOSA) of a compact-binary center of mass, imparted for example by a nearby tertiary perturber, imprints a Doppler modulation on the gravitational-wave signal and provides a single-event diagnostic of dynamical…
Space-based gravitational-wave (GW) laser interferometers, including LISA and Taiji, are designed to observe gravitational waves in the millihertz band and are expected to open up a frequency range that is otherwise inaccessible. The…
We obtain an exact analytical vacuum solution of Einstein-Aether theory with a strictly static aether configuration and investigate its maximal extension. The solution depends only on the coupling $c_{14}$ and reduces to the Schwarzschild…
We study primordial-black-hole (PBH) dark matter in the two-dark-dimensions (2DD) framework, a six-dimensional brane-world scenario with two compact extra dimensions and a fundamental gravity scale of order $10\,\mathrm{TeV}$. We calculate…
We investigate the dynamics of a charged massive scalar field around Kerr-Bertotti-Robinson Black Holes. By mapping the Klein-Gordon equation into a one-dimensional Schr\"odinger-like form and employing matched asymptotic expansions, we…
It is well known that the Einstein-scalar system of general relativity can in principle yield non-unique exact spinning naked singularities, which lead to unique Kerr black hole when the scalar field is switched off. It is a challenging…
We compute $\langle\hat{\Phi}^{2}\rangle_\text{ren}$ as well as the energy fluxes $\langle \hat{T}_{uu}\rangle_\text{ren}$ and $\langle \hat{T}_{vv}\rangle_\text{ren}$ (where $u$ and $v$ are the standard Eddington-Finkelstein coordinates)…
The hoop conjecture, due to Thorne, is a fundamental aspect of black holes in classical general relativity. Recently, generalized classes of regular spherically symmetric static black holes with arbitrary exponents coupled to nonlinear…
It is well-established that the Minkowski limit of pure $f(R)=R^2$ gravity breaks down, unlike that of full Starobinsky theory $f(R)=R+\alpha R^2$. We provide a novel interpretation of this phenomenon using the recent thermal analogy…
The dark shadow cast by a black hole, determined by the outermost unstable null circular geodesics (the photon sphere), provides a direct probe of strong-field gravity. In this work, we derive model-independent lower and upper bounds on the…
We propose a Lagrangian formulation for a non-conservative gravity model in which the divergence of the energy-momentum tensor in curved spacetime does not vanish. This is accomplished by introducing an arbitrary vector field that couples…
To answer the question posed in the title, we consider a novel diagnostic, viz., the difference in the times of arrival (TOA) at the observer of two light rays that simultaneously emanate from a source behind a spinning lens and pass by…
Increasing the circulating power in gravitational-wave detectors to the megawatt level is essential for future sensitivity improvement, but this is critically limited by optomechanical parametric instabilities. Current mitigation strategies…