Fundamental Cosmic Anisotropy and its Ramifications II: Perturbations in Bianchi spacetimes, and fixed in the Newtonian gaugeThe standard cosmological model is challenged by an ever-growing collection of observations, which invites (and stimulates) inquiry into possible additions and/or alterations. One such alteration…Robbert W. Scholtens, Marcello Seri, Holger Waalkens et al.·Apr 21, 2026SaveLearn
Abstract null hypersurfaces and characteristic initial value problems in General RelativityThis thesis is framed within the field of Mathematical Relativity and is organized into six chapters. After an introduction to the topic in Chapter 1, Chapter 2 reviews and further develops the…Gabriel Sánchez-Pérez·Apr 21, 2026SaveLearn
Understanding supernova gravitational waves with protoneutron star asteroseismologySupernovae are one of the most promising gravitational wave sources. But, since the system of the supernovae is nearly spherically symmetric, the expected gravitational waves from them are relatively…Hajime Sotani·Apr 21, 2026SaveLearn
Viability of Big Bang Nucleosynthesis in Some Generalized Horizon EntropiesIn this work, we investigate the viability of some cosmological models derived from generalized horizon entropies, using Big Bang Nucleosynthesis (BBN) constraints. By analyzing the deviations in the…Kajal Phukan, Rajdeep Mazumdar, Kalyan Malakar et al.·Apr 21, 2026SaveLearn
Quantum Spacetime, Quantum Gravity and Gravitized Quantum TheoryGeneral relativity is a background-independent theory of a dynamical classical spacetime geometry. Quantum theory is formulated in a classical spacetime, as an intrinsically probabilistic, contextual…Tristan Hübsch, Djordje Minic·Apr 21, 2026SaveLearn
Extrinsic geometry and Hamiltonian analysis of symmetric teleparallel gravityWe analyze the properties of foliations in presence of non-metricity, deriving the generalized Gauss-Codazzi relations in full generality. These results are employed to study the teleparallel…Salvatore Capozziello, Dario Sauro·Apr 21, 2026SaveLearn
The Flat Critical Branch Between Nariai and Bertotti-Robinson Geometries as a Solution of Cosmological Einstein-Maxwell TheoryWe analyze a class of product geometries of the form R1,1× Σ2 supported by electric, magnetic, or dyonic flux in the Einstein-Maxwell-Λ theory. These spacetimes belong to a…Metin Gurses, Tahsin Cagri Sisman, Bayram Tekin·Apr 21, 2026SaveLearn
Geometric Buoyancy-like Effects of Static Structures with Internal Stress in Schwarzschild SpacetimeIn curved spacetime, deformable bodies can undergo a displacement of their center of mass through cyclic internal motions without the use of propellant, as shown by Wisdom. In this paper, we…Yuji Takeuchi·Apr 20, 2026SaveLearn
Thermodynamic behavior of cosmological models with fractional entropyWe investigate the thermodynamic and phenomenological implications of a cosmological model governed by fractional entropy applied to the apparent horizon of a flat Friedmann-Lemaître-Robertson-Walker…Miguel Cruz, Diego da Silva, Simón González et al.·Apr 20, 2026SaveLearn
Van der Waals Gravity TheoryIn this study, we propose an extension of general relativity inspired by the van der Waals equation of state, incorporating non-ideal thermodynamic effects into the gravitational sector. Our approach…H. R. Fazlollahi·Apr 20, 2026SaveLearn
String-inspired Gauss-Bonnet Gravity Inflation and ACTIn this article we present a systematic observational verification of the ghost-free string-inspired f(R,G) model, where the Gauss-Bonnet invariant is non-minimally coupled to an…S. D. Odintsov, V. K. Oikonomou, Pyotr Tsyba et al.·Apr 20, 2026SaveLearn
Beyond Three Terms: Continued Fractions for Rotating Black Holes in Modified GravityBlack-hole ringdown offers a clean probe of strong gravity, but one of its most accurate tools--Leaver's continued-fraction method--requires a three-term recurrence relation. Beyond general…Georgios Karikos, Jayana A. Saes, Pratik Wagle et al.·Apr 20, 2026SaveLearn
Holographic dark energy as a source for slowly rotating wormholes: Implications for null geodesics and shadowsIn this work, we explore for the first time slowly rotating traversable wormholes embedded in holographic dark energy. We focus on three representative holographic dark energy models -- Rényi, mixed,…A. Errehymy, S. K. Maurya, M. Govender et al.·Apr 20, 2026SaveLearn
Macroscopic Optical Nonreciprocity: A Black Hole as an Optical DiodeOptical reciprocity--the principle that light retraces the same path when source and detector are interchanged--is a foundational concept in geometric optics. In this Letter, we demonstrate that this…Wentao Liu, Di Wu, Xiongjun Fang et al.·Apr 20, 2026SaveLearn
Including higher-order modes in a quadrupolar eccentric numerical relativity surrogate using universal eccentric modulation functionsgwNRHME is a framework that converts multi-modal (i.e., containing several spherical harmonic modes) quasi-circular waveforms into their eccentric counterparts, provided the quadrupolar…Tousif Islam, Adhrit Ravichandran, Peter James Nee et al.·Apr 20, 2026SaveLearn
Quantum-Deformed Phase-Space Geometry and Emergent Inflation in Effective Four-Dimensional SpacetimeWe develop a phase-space approach to quantum-deformed gravity. Reducing it to an effective four-dimensional spacetime structure facilitates reanalyzing cosmic inflation and quantum gravity dynamics.…Swapnil Kumar Singh, Saleh O. Allehabi, Azzah A. Alshehri et al.·Apr 19, 2026SaveLearn
Sachs Equations and Plane Waves VI: Penrose LimitsLet (M,g) be a Lorentzian manifold whose local space N of unparametrized null geodesics is smooth. We show that its Penrose limits assemble into a smooth bundle of plane-wave germs with…Jonathan Holland, George Sparling·Apr 19, 2026SaveLearn
Geometric deformations of symmetric spacetimes with a string cloudWe establish a deformation framework for highly symmetric solutions to the Einstein equations. In this framework, four-dimensional metrics are constructed from three-dimensional η-Einstein metrics…Hiroshi Kozaki, Satsuki Matsuno, Tatsuhiko Koike et al.·Apr 19, 2026SaveLearn
Parameter Estimation of the Gravitational-Wave Angular Power Spectrum in the Dirty-Map SpaceWe consider a search for the anisotropic stochastic gravitational-wave background (SGWB) that decomposes the sky map into its spherical harmonics components in order to obtain estimators of the…Erik Floden, Alex Granados, Vuk Mandic·Apr 19, 2026SaveLearn
Deterministic Trust Regions for Finite-Window Black-Hole Spectroscopy in GW250114We study finite-window black-hole spectroscopy in the loud-event regime and ask when a multimode ringdown fit supports a stable common-remnant Kerr interpretation. Starting from whitened, tapered…Ruiliang Li·Apr 19, 2026SaveLearn
Comment on Cosmological constraints on unimodular gravity models with diffusion (arXiv:2211.07424): thermodynamic inadmissibility of the H0 tension resolution mechanismWe show that the diffusion-based models proposed in Refs.~Perez2021,Landau2022 within the framework of Unimodular Gravity (UG) to alleviate the H0 tension are incompatible with the second…Mauricio Cataldo·Apr 19, 2026SaveLearn
Weak Gravitational Lensing: A Brief OverviewGravitational lensing constitutes one of the most direct observational manifestations of spacetime curvature and provides a powerful probe of compact astrophysical objects. In this work, we present a…Partha Pratim Basumallick, Saheb Das, Bhaswati Mandal et al.·Apr 19, 2026SaveLearn
Generalized relative locality and causal setsIn this paper we introduce a new general framework for the study of phenomenological quantum gravity theories (PQG). The key idea is the introduction of two different types of spacetime, an…Andrea Bevilacqua, Alice Boldrin·Apr 19, 2026SaveLearn
Quasinormal modes of the generalized JMN naked singularity using exact WKB analysisIn this paper, we study the quasinormal modes of the generalized Joshi-Malafarina-Narayan (JMN) naked singularity spacetime using the exact Wentzel-Kramers-Brillouin (WKB) method. Working in the…Aryansh Saxena, Suresh C. Jaryal, K. K. Sharma·Apr 19, 2026SaveLearn
Signatures of Quantum Gravity In Relativistic Quantum SystemsIn this thesis, we have used a linearized quantum gravity setting to investigate the effects of gravitons on matter systems. Based on the graviton-matter interaction, we have then proposed detector…Soham Sen·Apr 18, 2026SaveLearn