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.

Constraints on primordial black holes from the first part of LIGO-Virgo-KAGRA fourth observing run

Using LIGO-Virgo-KAGRA O4a data, this study establishes the strongest constraints to date on the abundance of primordial black holes in the 0.6100M0.6-100 M_\odot mass range, finding no compelling evidence for their contribution to observed gravitational wave events despite allowing for a subset of cataloged mergers to be primordial in origin.

M. Andrés-Carcasona, A. J. Iovino, E. Vallejo-Pagès, V. Vaskonen, H. Veermäe, M. Martínez, Ll. M. Mir2026-05-18⚛️ gr-qc

Hamiltonians to all Orders in Perturbation Theory and Higher Loop Corrections in Single Field Inflation with PBHs Formation

This paper derives all-order interaction Hamiltonians and non-linear field relations for single-field inflation with a transient ultra-slow-roll phase, demonstrating that loop corrections to long-wavelength perturbations grow rapidly as (ΔNPeL)L(\Delta N \mathcal{P}_e L)^L, thereby causing a breakdown of perturbative control at the fourth loop order in standard models used for primordial black hole formation.

Hassan Firouzjahi, Bahar Nikbakht2026-05-15⚛️ hep-ph

On the Limits of the Thermofield-Double Interpretation of the Minkowski Vacuum

This paper argues that while the Thermofield-Double (TFD) interpretation of the Minkowski vacuum is a useful calculational tool for capturing thermal features, it is not an exact description of the vacuum's Hilbert space structure, as evidenced by systematic mismatches in higher-derivative correlators and the fact that TFD-like forms can be artificially generated through alternative coordinate choices.

Vaibhav Wasnik2026-05-15⚛️ gr-qc