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Recent years have witnessed a rise in interest in the geometrical trinity of General Relativity and its extensions. This interest has been fuelled by novel insights into the nature of gravity, the possibility to address computational and conceptual questions—such as the determination of black hole entropy or the definition of gravitational energy–momentum—from a new perspective. In particular, f (Q) gravity has also inspired numerous works on black holes, wormholes, and cosmology. In the latter case, f (Q) models have the potential to elucidate phenomena in both early and late-time cosmology without necessitating the inclusion of dark energy, the inflaton field, or dark matter. Particularly noteworthy is the role of f (Q) theories in addressing cosmological tensions, presenting exciting possibilities for reshaping our understanding of gravity and its manifestations in cosmology. The emergence of intriguing new black hole solutions and the potential existence of wormhole solutions suggest the presence of novel physics within the realm of strong gravity. These phenomena have become increasingly measurable only in recent times, opening up exciting avenues for further exploration and discovery. This review is tailored to students and researchers alike. It offers a self-contained and pedagogical introduction to metric-affine geometry—The mathematical foundation and indispensable tool upon which the geometrical trinity of General Relativity as well as its various extensions are built. [ABSTRACT FROM AUTHOR]

Under high power UV irradiation, radicals can be generated from double bonds through photodissociation, H‐abstraction, or oxygen initiation mechanisms. This eliminates the need for externally added initiators in photopolymerization. This study investigates high‐power sunlight‐simulated UV‐induced free radical polymerization under various experimental conditions, including the presence of inhibitors, open or closed systems, and partial degassing. Additionally, high‐power sunlight‐simulated UV‐induced atom transfer radical polymerization is explored by externally adding CuBr2/ligand (1:2) catalyst at 100 or 1000 ppm molar concentration of copper. Delicate fabrication of real‐world thin films, coatings, and delicate 3D composites further demonstrates the high reliability and versatility of this technology. [ABSTRACT FROM AUTHOR]

Gravitational waveforms play a crucial role in comparing observed signals with theoretical predictions. However, obtaining accurate analytical waveforms directly from general relativity (GR) remains challenging. Existing methods involve a complex blend of post-Newtonian theory, effective-one-body formalism, numerical relativity and interpolation, introducing systematic errors. As gravitational wave astronomy advances with new detectors, these errors gain significance, particularly when testing GR in the nonlinear regime. A recent development proposes a novel approach to address this issue. By deriving precise constraints—or balance laws—directly from full nonlinear GR, this method offers a means to evaluate waveform quality, detect template weaknesses and ensure internal consistency. Before delving into the intricacies of balance laws in full nonlinear GR, we illustrate the concept using a detailed mechanical analogy. We will examine a dissipative mechanical system as an example, demonstrating how mechanical balance laws can gauge the accuracy of approximate solutions in capturing the complete physical scenario. While mechanical balance laws are straightforward, deriving balance laws in electromagnetism and GR demands a rigorous foundation rooted in mathematically precise concepts of radiation. Following the analogy with electromagnetism, we derive balance laws in GR. As a proof of concept, we employ an analytical approximate waveform model, showcasing how these balance laws serve as a litmus test for the model's validity. This article is part of the theme issue 'The particle-gravity frontier'. [ABSTRACT FROM AUTHOR]

This article discusses the interface between particle physics and gravity in our quest to understand the deep structure of the Universe. It highlights open puzzles in physics, such as the nature of neutrinos, the matter-antimatter asymmetry, the existence of dark matter and dark energy, and the stability of the Higgs vacuum. The article also explores experimental and theoretical approaches to address these questions, including high-energy collider experiments, precision measurements, astroparticle physics, and cosmology surveys. It concludes by emphasizing the importance of interdisciplinary collaboration and inspiring young scientists to join this field of research. [Extracted from the article]