General Relativity and Quantum Cosmology Papers of the Week

We present the results for gravitational-wave lensing searches on the data from the first part of the fourth LIGO–Virgo–KAGRA observing run (O4a).

We investigate general properties of quasi-topological theories of gravity involving infinite towers of polynomial densities and of their regular vacuum black hole solutions.

The nontrivial asymptotic structure of rotating black holes in the Bertotti-Robinson universe complicates a direct determination of their conserved mass, leading previous studies to rely on a priori thermodynamic input. We address this long-standing problem using integrability methods, establish local analytic existence and uniqueness via the Cauchy-Kovalevskaja theorem, and obtain a closed expression via a rescaled recurrence whose termination is proved at all orders.

We develop and validate a physics-informed neural network (PINN) framework for computing the tidal Love numbers of black holes directly from their perturbation equations.

In this thesis, we study classical black hole scattering, systematically including spin---an important feature of real astrophysical systems---to describe Kerr black hole dynamics.

We show that the answer is no for static, spherically symmetric RBHs supported by a radial scalar field within a broad class of ST theories.

We show that the convergence region of the QNM representation of the retarded Green's function of the Kerr spacetime is set by complex-time bouncing singularities, as in our previous work for the Schwarzschild case.

Non-rotating calculations or approximate rotational corrections can bias equation of state inference and limit the fidelity of population synthesis in tracing the evolutionary history of progenitors and propagating equation of state uncertainties. In this \textit{Letter}, we develop physics-informed neural operators that can solve the axisymmetric problem with high accuracy and negligible computational cost.

In this work, we investigate extra-dimensional modifications to GW generation within a compactified Kaluza--Klein framework.

We present a systematic study of the spin evolution of accreting black holes.

In this work, we introduce the structured pseudospectrum into black hole perturbation theory.

In this work, we calculate Kerr metric perturbations with a new computational approach based on numerical relativity methods, extending recent scalar self-force results to full general relativity.

We study axial (odd-parity) perturbations about static and spherically-symmetric curvaturised black hole solutions of purely-metric Horndeski theories.

We derive the wave functional of the field on the nucleation slice from the half-bounce path integral, and use it to compute the root-mean-square quadrupole moment of a bubble at nucleation.

The large-order behavior of the expansion coefficients encodes physical information inaccessible at any finite order, so cosmological EFTs contain hidden data. Using resurgence analysis, we show how this information can be systematically extracted to recover exact and non-perturbative predictions from the perturbative expansion.

We investigate gravitational waves from extreme mass ratio inspirals in an axisymmetric Finslerian extension of the Schwarzschild spacetime.

We present a calculation of the first-order metric perturbation arising from a point mass moving on a circular, equatorial orbit in Kerr spacetime.

A finite test body is nevertheless not a passive probe: it distorts the scalar field that accelerates it. We show that this field distortion produces a differential acceleration between concentric test masses, even when their microscopic coupling is universal.

In the weak-field regime of quantum electrodynamics (QED) the relative mass correction is $-1.5\times10^{-5}(E_{\max}/E_c)^2$, so the larger couplings describe the quartic model as an effective nonlinear electrodynamics rather than a controlled QED correction.

Because runs differing by as little as $\sim 10^{-10}$ in the metric decorrelate completely once the shock-cone instability saturates, we compare models statistically using ensembles of independent realizations.