⚛️ Category

gr-qc

3099 papers

Quantum gravity represents the frontier where the very large meets the very small, attempting to unify Einstein's theory of gravity with the strange rules of quantum mechanics. This field explores the fundamental fabric of spacetime, seeking to understand how the universe behaves at its most extreme scales, from the heart of black holes to the moment of the Big Bang. Because these concepts often involve complex mathematics, they can feel distant to non-specialists, yet they hold the key to a complete picture of physical reality.

At Gist.Science, we bridge this gap by processing every new preprint in this category directly from arXiv. Our team provides both plain-language explanations and detailed technical summaries for each paper, ensuring that groundbreaking research is accessible to everyone, from curious students to seasoned researchers. Below are the latest papers in quantum gravity, offering fresh insights into the nature of our cosmos.

⚛️ general relativity

General Relativistic Entropic Acceleration at the perturbation level: a CLASS implementation and first Boltzmann-code constraints

This paper presents the first implementation of General Relativistic Entropic Acceleration (GREA) within the CLASS Boltzmann solver and provides the first cosmological constraints on its coupling parameter α\alpha using CMB, BAO, and supernova data, demonstrating that the model fits observations nearly as well as Λ\LambdaCDM while predicting a distinctive phantom-divide crossing at z≃2z \simeq 2.

Simone D'Onofrio, Dong Ha Lee, Eleonora Di Valentino, Juan García-Bellido2026-07-29
⚛️ general relativity

Analytic backreaction of a scalar wig on a Schwarzschild black hole

This paper analytically determines the leading-order backreaction of a spherically symmetric massive scalar quasi-bound state on a Schwarzschild black hole in the small-coupling regime, deriving explicit metric perturbations and demonstrating that the black hole's mass grows monotonically as it absorbs the decaying scalar cloud while maintaining perturbative consistency.

Marco de Cesare, Manuel Del Piano, Carlos A. R. Herdeiro2026-07-29
⚛️ phenomenology

Probing Fundamental Constant Oscillation in the Galactic Center with S-Star Spectroscopy

This paper proposes using precise, time-resolved spectroscopy of S-stars orbiting the supermassive black hole Sgr A* to detect coherent temporal oscillations of the fine-structure constant induced by ultralight scalar fields, thereby enabling stringent constraints on scalar-photon couplings within the Galactic Center's high-density environment.

Zhaoyu Bai, Vitor Cardoso, Yifan Chen, Tuan Do, Aurélien Hees, Huangyu Xiao, Xiao Xue2026-07-28
⚛️ general relativity

A Modified Gravitational Theory of the Matter Sector of the Type ϕ(R,T)Lm\phi(R,T)\mathcal{L}_{m}

This paper proposes a modified gravitational theory where the matter Lagrangian is weighted by a function of the energy-momentum trace, ϕ(T)\phi(T), to naturally resolve cosmological singularities through a nonsingular bounce while preserving the empirical successes of standard Λ\LambdaCDM cosmology and local gravity tests.

Gines R. Pérez Teruel, Antonio Peña Peña2026-07-28
⚛️ general relativity

Optical appearance of regularized compact objects without an exterior photon sphere

This paper demonstrates that regularized compact objects lacking an exterior photon sphere can produce shadow appearances indistinguishable from Schwarzschild black holes, with their dark regions determined by the regular core rather than unstable photon orbits, while remaining consistent with Event Horizon Telescope observations of Sgr A* and M87.

Ashok B. Joshi, Vishva Patel, Parth C. Varasani2026-07-28
⚛️ general relativity

Black hole solutions with a linear equation of state in Hořava gravity and Einstein--æther theory

This paper presents a procedure for deriving spherically symmetric black hole solutions in Hořava gravity and Einstein--æther theory by specifying linear equations of state rather than energy density profiles, revealing exotic physical and thermodynamic behaviors such as effective electric-potential terms, nn-fold degenerate extremal horizons, and black hole remnants with central singularities.

Milko Estrada2026-07-28