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The immense computational cost of simulating turbulence has motivated the use of machine learning approaches for super-resolving turbulent flows. A central challenge is ensuring that learned models respect physical symmetries, such as…

Following Thurston's geometrisation picture in dimension three, we study geometric manifolds in a more general setting in arbitrary dimensions, with respect to the following problems: (i) The existence of maps of non-zero degree (domination…

Geometric Topology · Mathematics 2025-08-15 Christoforos Neofytidis

In this paper we present cosmological constraints on several well-known $f(R)$ models, but also on a new class of models that are variants of the Hu-Sawicki one of the form $f(R)=R-\frac{2\Lambda}{1+b\;y(R,\Lambda)}$, that interpolate…

Cosmology and Nongalactic Astrophysics · Physics 2018-01-29 Judit Pérez-Romero , Savvas Nesseris

We discuss the advantages of using metric theories of gravity with curvature-matter couplings in order to construct a relativistic generalisation of the simplest version of Modified Newtonian Dynamics (MOND), where Tully-Fisher scalings are…

General Relativity and Quantum Cosmology · Physics 2021-04-06 E. Barrientos , T. Bernal , S. Mendoza

We pursue a program to confront observations with inhomogeneous extensions of the FLRW metric. The main idea is to test the Copernican principle rather than assuming it a priori. We consider the $\Lambda$CDM model endowed with a spherical…

Cosmology and Nongalactic Astrophysics · Physics 2021-11-23 David Camarena , Valerio Marra , Ziad Sakr , Chris Clarkson

A new criterion for inextendibility of expanding cosmological models with symmetry is presented. It is applied to derive a number of new results and to simplify the proofs of existing ones. In particular it shows that the solutions of the…

General Relativity and Quantum Cosmology · Physics 2010-11-05 Mihalis Dafermos , Alan D. Rendall

Theoretical and observational challenges to standard cosmology such as the cosmological constant problem and tensions between cosmological model parameters inferred from different observations motivate the development and search of new…

Cosmology and Nongalactic Astrophysics · Physics 2023-06-30 Lucas Lombriser

We considered non-minimally coupled curvature-matter models of gravity in a FRW universe filled with perfect fluid and investigated its cosmological implications in the light of Pantheon compilation of 1048 Supernovae Ia data points along…

General Relativity and Quantum Cosmology · Physics 2023-08-31 Biswajit Jana , Anirban Chatterjee , Kumar Ravi , Abhijit Bandyopadhyay

A simple speed-up cosmology model is proposed to account for the dark energy puzzle. We condense contributions from dark energy and curvature term into one effective parameter in order to reduce parameter degeneracies and to find any…

Astrophysics · Physics 2007-10-10 Xin-He Meng , Meng Su , Zheng Wang

The tension between the Hubble constant obtained from the local measurements and from cosmic microwave background (CMB) measurements motivated us to consider the cosmological model beyond $\Lambda$CDM one. We investigate the cosmology in…

General Relativity and Quantum Cosmology · Physics 2022-06-15 Jing Li , Yongxiang Zhou , Xun Xue

Modified theories of gravity encompass a class of $f(R)$-models that seek to elucidate the observed late time accelerated expansion of the universe. In this study, we examine a set of viable $f(R)$ models (Hu-Sawicki: two cases,…

Cosmology and Nongalactic Astrophysics · Physics 2023-12-15 Kumar Ravi , Anirban Chatterjee , Biswajit Jana , Abhijit Bandyopadhyay

We present cosmological constraints for the flat $\Lambda$CDM model, including the sum of neutrino masses, by performing a multi-probe analysis of a total of 13 tomographic auto- and cross-angular power spectra. This is achieved by…

Cosmology and Nongalactic Astrophysics · Physics 2021-10-11 Raphael Sgier , Christiane Lorenz , Alexandre Refregier , Janis Fluri , Dominik Zürcher , Federica Tarsitano

We elaborate on nonmetric geometric flow theory and metric-affine gravity with applications in modern cosmology. Two main motivations for our research follow from the facts that 1) cosmological models for $f(Q)$ modified gravity theories,…

General Relativity and Quantum Cosmology · Physics 2024-10-08 L. Bubuianu , E. Nurlan , J. O. Seti , S. Vacaru , E. V. Veliev

We investigate anisotropic and homogeneous cosmological models in the scalar-tensor theory of gravity with non-minimal kinetic coupling of a scalar field to the curvature given by the function $\eta\cdot(\phi/2)\cdot G_{\mu\nu}\,\nabla^\mu…

General Relativity and Quantum Cosmology · Physics 2025-05-13 Ruslan K. Muharlyamov , Tatiana N. Pankratyeva , Shehabaldeen O. A. Bashir

Void models provide a possible explanation of the "accelerated expansion" of the Universe without dark energy. To make the conventional void models more realistic, we allow the void, an underdense region around us, to be anisotropic and…

Cosmology and Nongalactic Astrophysics · Physics 2009-06-29 Masayuki Tanimoto , Yasusada Nambu , Kazuhiro Iwata

Recent discoveries, e.g., by JWST and DESI, have elevated the level of tension with inflationary $\Lambda$CDM. For example, the empirical evidence now suggests that the standard model violates at least one of the energy conditions from…

General Physics · Physics 2026-02-18 Namit Chandak , Fulvio Melia , Junjie Wei

The cosmological principle assumes the isotropy of the Universe at large scales. It is a foundational assumption in the $\Lambda$CDM model, which is the current standard model of cosmology. Recent tensions give legitimacy to investigating…

We perform the first comprehensive constraints on two Finslerian models, i.e., the simplest Finslerian $\Lambda$CDM (F$\Lambda$) and non-flat F$\Lambda$ models using the Type Ia supernovae, baryonic acoustic oscillations, cosmic microwave…

Cosmology and Nongalactic Astrophysics · Physics 2021-03-30 Deng Wang , Xin-He Meng

Under the premise that the current observations of the cosmic microwave background radiation set a very stringent limit to the anisotropy of the universe, we consider an anistropic model in the presence of a barotropic perfect fluid and a…

General Relativity and Quantum Cosmology · Physics 2020-06-02 J. Socorro , S. Pérez-Payán , Abraham Espinoza-García , Luis Rey Díaz-Barrón

The Cosmic Microwave Background (CMB) anisotropy constrains the geometry of the Universe because the positions of the acoustic peaks of the angular power spectrum depend strongly on the curvature of underlying three-dimensional space. In…

Astrophysics · Physics 2009-11-13 J. Dunkley , M. Bucher , P. G. Ferreira , K. Moodley , C. Skordis
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