gr-qc

Quantum-information diagnostics of cosmological perturbations with nontrivial sound speed in inflation

Accelerating scaling solutions from dark matter particle creation

This paper demonstrates that accelerating scaling attractors in a two-fluid cosmological system with dark matter particle creation can emerge without dark energy, but only when the energy exchange is driven by dark matter density and flows from dark matter to the second fluid.

Unitary Time Evolution and Vacuum for a Quantum Stable Ghost

This paper demonstrates that a quantum system comprising a harmonic oscillator polynomially coupled to a ghost with negative kinetic energy can be consistently quantized with a well-defined vacuum and manifestly unitary evolution, provided the system possesses an integral of motion with a positive discrete spectrum that ensures stability despite the Hamiltonian's unbounded spectrum.

Mitigating Systematic Errors in Parameter Estimation of Binary Black Hole Mergers in O1-O3 LIGO-Virgo Data

This study demonstrates that a data-driven parameter estimation framework incorporating broad priors on waveform phase and amplitude uncertainties effectively mitigates systematic errors in LIGO-Virgo O1-O3 binary black hole merger analyses, thereby resolving inconsistencies across different waveform models and data processing methods for key events like GW191109\_010717 and GW200129\_065458.

Basic geometric and kinematic features of the Standard Cosmological Model

This paper presents a historical overview and quantitative analysis of the Standard Cosmological Model ($\Lambda$CDM), deriving key geometric and kinematic equations to determine critical moments in cosmic evolution, such as the onset of accelerated expansion and component density equalities, while also exploring concepts like horizons and the universe's remote future.

Ti and Spi, Carrollian extended boundaries at timelike and spatial infinity

This paper defines invariant, Carrollian-geometric extended boundaries at timelike and spatial infinity (Ti and Spi) for asymptotically flat spacetimes, demonstrating their utility in characterizing asymptotic symmetries, realizing massive field scattering data, and naturally recovering the BMS and Poincaré groups along with Strominger's matching conditions.

Exploring Born-Infeld f(T) teleparallel gravity through accretion disk dynamics

This study investigates the impact of Teleparallel Born-Infeld gravity on thin accretion disk dynamics, demonstrating that X-ray spectral observations can effectively distinguish its predictions from General Relativity and potentially constrain the theory.

Derivative coupling in horizon brightened acceleration radiation: a quantum optics approach

This paper investigates Horizon Brightened Acceleration Radiation (HBAR) using derivative coupling between atoms and field momentum to resolve infrared divergences, revealing that point-like detectors exhibit frequency-independent transition probabilities due to local gravitational effects and that finite-size detectors may induce non-equilibrium thermodynamic states.

Disentangling spinning and nonspinning binary black hole populations with spin sorting

This study demonstrates that by sorting binary black hole components by spin magnitude rather than mass, researchers can reliably distinguish between spinning and nonspinning populations despite current modeling limitations, concluding that observed data rules out a fully nonspinning population but supports scenarios where up to 80% of sources are nonspinning or only one component per binary is spinning.

Testing Gauss-Bonnet Gravity with DESI BAO Data

Using Pantheon Plus supernovae, cosmic chronometer, and DESI BAO data, this study employs MCMC simulations to show that both power-law and exponential f(G) gravity models are statistically favored over the standard ΛCDM model, with the exponential variant uniquely predicting a future transition back to a decelerating phase.