广义相对论与量子宇宙学

We unveil the dynamical equivalence of field theories with non-canonical kinetic terms and canonical theories with a volume element invariant under transverse diffeomorphisms. The proof of the equivalence also reveals a subtle connection…

We construct the Hamiltonian formulation of the isotropic Universe in a generic metric f(R)-theory in the Jordan frame. We canonically quantize the Universe volume via a polymer formulation, and we adopt the scalar field naturally arising…

Effective models inspired by loop quantum gravity typically resolve the central singularity by replacing it with a bounce of the matter density in the Planckian regime. In the specific model analyzed here, this bounce is generally followed…

In this work, we introduce a novel framework to investigate ringdown gravitational waveforms in the presence of dynamical matter fields outside the horizon of a black hole. We systematically analyze two distinct scenarios of dynamical…

For the centennial of quantum mechanics, we offer an overview of the central role played by quantum information and thermalization in problems involving fundamental properties of spacetime and gravitational physics. This is an open area of…

The standard $\Lambda$CDM model, based on a highly symmetric FLRW geometry, successfully explains many observations but faces unresolved issues, motivating the exploration of alternative cosmological frameworks. We investigate the influence…

We present an asymptotically flat spherically symmetric non-singular metric that describes gravitational collapse and matter bounce with transient black hole and white hole regions. The metric provides a dynamical counterpart to proposed…

The evolution of density perturbations is analysed in a modified theory of gravity with a nonminimal coupling between curvature and matter. We consider the broken degeneracy between the choices of matter Lagrangian for a perfect fluid,…

Galactic double white dwarf (DWD) binaries are among the guaranteed sources for the Laser Interferometer Space Antenna (LISA), an upcoming space-based gravitational wave (GW) detector. Most DWDs in the LISA band are far from merging and…

We develop the covariant phase space formulation of Weyl-transverse gravity (WTG) in the presence of general timelike and spacelike boundaries. WTG is classically equivalent to General Relativity (GR) but possesses a reduced gauge symmetry…

The formation of a cusp on a black hole shadow is a striking signature of physics beyond the Kerr paradigm. We demonstrate that this morphological change fundamentally alters the shadow's topology with the topological charge flipping from 1…

Inspired by regular black holes (RBHs) sourced by dark matter halos, we generalize the anisotropic energy-momentum tensor by relaxing the $P_r = -\rho$ condition between radial pressure and density. We demonstrate that while RBHs are a…

We present a closed-form surrogate for the equivalent diameter of the Kerr black-hole shadow, defined as the diameter of the circle with the same area as the shadow's critical curve. The construction enforces the exact face-on (polar) limit…

Accurately calibrating the center-of-mass (CoM) offset between the spacecraft (SC) and the inertial sensor test mass (TM) is crucial for space-based gravitational-wave (GW) antennas, such as LISA and Taiji. Current calibration methods…

Pulsar timing arrays (PTAs) are limited in localizing nanohertz continuous gravitational waves (CGWs) by uncertainties in pulsar distances. We introduce a method to infer pulsar distances in two dimensions, using phase information from the…

We study the dynamics of spatially homogeneous Friedmann--Robertson--Walker universes filled with a massive scalar field in a neighbourhood of the massless transition $s=1$. At this point the Einstein--scalar system exhibits a…

Spacetimes in general relativity can be uniquely decomposed into a set of multipole moments. Given the usefulness of moments in the categorization of radiation patterns, tidal deformations, and other phenomena associated with compact…

We provide a short introduction to ``Lorentzian metric spaces" i.e., spacetimes defined solely in terms of the two-point Lorentzian distance. As noted in previous work, this structure is essentially unique if minimal conditions are imposed,…

The quantum nature of the Schwarzschild black hole interior is investigated through the Wheeler-DeWitt (WDW) equation. The interior of a static, spherically symmetric black hole is described by the Kantowski-Sachs (KS) metric, which…

The LIGO, Virgo, and KAGRA (LVK) gravitational-wave observatories have opened new scientific research in astrophysics, fundamental physics, and cosmology. The collaborations that build and operate these observatories release the…