Specialty
A mathematical study reports a continuous way to extend a family of theoretical black-hole spacetimes beyond a surface where the radial coordinate approaches infinity, but the global picture depends on direction and the chosen construction.
Scientific publication3 min read
A formal analysis finds exactly two symmetry-preserving directions for splitting a gravity connection into shape and scale, while the resulting choices form a smooth one-dimensional family. It recovers Palatini dynamics in the exact sector but does not establish that the broader construction describes a physical theory.
Scientific publication4 min read
A preprint comparing two f(Q) gravity models finds that one is favored by several data combinations, but the result changes with the Type Ia supernova compilation.
Scientific publication4 min read
A theoretical preprint derives pair-creation probabilities across three field spins and estimates an extremely low massless rate for HM Cancri, with larger figures appearing only in an extrapolation beyond the model's nonrelativistic regime.
Scientific publication4 min read
A theoretical analysis finds that two effective quantum-corrected black-hole metrics make different predictions for horizons, photon spheres, shadows and parameter bounds.
Scientific publication4 min read
A Horndeski model produces a less negative 21-cm signal than ΛCDM in the selected redshift range, while its spin temperature remains a first approximation.
Scientific publication3 min read
A mathematical analysis gives a sufficient condition for telling pure singularities apart from points at infinity. The result works under specific geometric assumptions and classifies the Penrose boundary of maximally extended Schwarzschild spacetime.
Scientific publication4 min read
A new arXiv preprint reports a fully 3D scheme for linear waves on compactified hyperboloidal slices of fixed Minkowski space. Its tests reached infinity, kept discrete energy aligned with the continuum reference and showed near-second-order convergence, while a massive case exposed weaker radial convergence.
Scientific publication3 min read
A mathematical analysis of massive Dirac fields around rotating black holes reports that stationary source-free condensates cannot remain nonzero on the horizon under the paper's boundary conditions. It also finds a filled, oblate angular structure rather than a hollow torus for rotating modes.
Scientific publication4 min read
A theoretical preprint finds that reconstructing metric f(R) gravity from generalized horizon entropy produces branch-dependent Lagrangians and stability conditions.
Scientific publication3 min read
A theoretical preprint reports selected parameter cases with continued expansion and curvature approaching zero, while another modeled case reaches a singularity.
Scientific publication4 min read
An arXiv preprint reports a mathematical theorem ruling out nontrivial outgoing massless scalar-wave modes with a nonnegative imaginary part of the frequency across the full subextremal Kerr-de Sitter range. It leaves extremal black holes, lower-half-plane modes and general-spin Teukolsky equations open.
Scientific publication3 min read
A modeling study finds atmospheric pressure fluctuations are unlikely to limit present torsion-balance measurements of G under its benchmark assumptions. The authors say the issue will become more important as experiments pursue lower uncertainty.
Scientific publication5 min read
A methods preprint sets out a common way to turn calibrated torsion-balance spectra into bounds on known torque signals and additional stochastic noise, then tests the approach against two illustrative benchmarks.
Scientific publication4 min read
A mathematical model of a detector falling toward a Schwarzschild–MOG black hole finds a horizon thermal factor only after near-horizon and branch-isolation conditions are imposed.
Scientific publication4 min read
A theoretical study links the small variation in neutron-star universal relations to fading interior information, while numerical phase-transition sequences show larger departures.
Scientific publication4 min read
The largest sampled distance shift was 2176.407 picometres in the Sun-Jupiter-Saturn benchmark, while the calculations showed no evidence of monotonic or secular growth.
Scientific publication3 min read
A theoretical Einstein–Maxwell calculation follows one time-dependent charged, radiating stellar interior. It reports favorable and unfavorable diagnostics, while its exact solution is limited to a special mathematical construction.
Scientific publication5 min read
A theoretical calculation coupling freezing gravity to a minimally coupled perfect fluid retains the model’s separation between background and perturbation physics and its linear large-scale freezing. It also derives analytic conditions for ghost and gradient stability, while leaving nonlinear behavior and strong coupling unresolved.
Scientific publication4 min read
The study models a family of asymptotically de Sitter spacetimes and compares their simulated shadows, photon rings and axial gravitational quasinormal modes. Its main contrast is between modest optical changes and more pronounced shifts in part of the calculated spectrum.
Scientific publication3 min read
A numerical arXiv preprint reports that five simulated compact-binary inspirals with spin inversions were matched extremely closely by physically evolving waveforms in which spin projections never crossed zero. The result points to a modeling degeneracy that future complete-waveform studies will need to test.
Scientific publication5 min read
A new arXiv preprint models a spherical star whose core contains ordinary matter and a second component interpreted as dark matter. The calculations identify where the model has finite positive central pressure, trace how its critical compactness changes with core parameters, and show that the same overall compactness can conceal different internal matter distributions.
Scientific publication5 min read
A theoretical preprint presents a target-space method for generating exact Einstein–sigma-model and tensor–multiscalar solutions from selected Ricci-flat geometries. Its strongest results are local and conditional, and one black-hole example develops a curvature singularity in the nontrivial scalar branch.
Scientific publication3 min read
A computational study finds a sharp split in performance: the model was internally calibrated when it generated and recovered its own waveforms, but showed systematic bias when machine-learning waveforms recovered effective-one-body signals.
Scientific publication3 min read