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A modified Mimetic gravity (MMG) is proposed as a generalization of general relativity. The model contain a physical metric which is function of an auxiliary (unphysical) metric and a Lyra's metric. We construct different kinds of…

General Relativity and Quantum Cosmology · Physics 2015-04-07 Davood Momeni , Aziza Altaibayeva , Ratbay Myrzakulov

We present the first field-level comparison of cosmological N-body simulations, considering various widely used codes: Abacus, CUBEP$^3$M, Enzo, Gadget, Gizmo, PKDGrav, and Ramses. Unlike previous comparisons focused on summary statistics,…

We propose a new cosmological framework in which the strength of the gravitational force acted on dark matter at late time can be weaker than that on the standard matter fields without introducing extra gravitational degrees of freedom. The…

Cosmology and Nongalactic Astrophysics · Physics 2021-04-14 Antonio De Felice , Shinji Mukohyama

Assuming a spatially flat universe, we study the cosmological viability of an infrared corrected teleparallel gravity model, which accounts for late acceleration by weakening gravity at later times on cosmological distances. The theory does…

Cosmology and Nongalactic Astrophysics · Physics 2023-01-11 Mahmoud Hashim , Waleed El Hanafy , Alexey Golovnev , Amr A. El-Zant

The reconstruction scheme is developed for modified $f(R)$ gravity with realistic matter (dark matter, baryons, radiation). Two versions of such theory are constructed: the first one describes the sequence of radiation and matter…

High Energy Physics - Theory · Physics 2008-11-26 Shin'ichi Nojiri , Sergei D. Odintsov

To effectively exploit large-scale structure surveys, we depend on accurate and reliable predictions of non-linear cosmological structure formation. Tools for efficient and comprehensive computational modelling are therefore essential to…

Cosmology and Nongalactic Astrophysics · Physics 2020-10-07 Benjamin Bose , Matteo Cataneo , Tilman Tröster , Qianli Xia , Catherine Heymans , Lucas Lombriser

In this work we present a novel approach for computing correspondences between non-rigid objects, by exploiting a reduced representation of deformation fields. Different from existing works that represent deformation fields by training a…

Computer Vision and Pattern Recognition · Computer Science 2022-11-29 Ramana Sundararaman , Riccardo Marin , Emanuele Rodola , Maks Ovsjanikov

A general nonperturvative loop quantization procedure for metric modified gravity is reviewed. As an example, this procedure is applied to scalar-tensor theories of gravity. The quantum kinematical framework of these theories is rigorously…

General Relativity and Quantum Cosmology · Physics 2013-04-09 Xiangdong Zhang , Yongge Ma

We compare and validate COLA (COmoving Lagrangian Acceleration) simulations against existing emulators in the literature, namely Bacco and Euclid Emulator 2. Our analysis focuses on the non-linear response function, i.e., the ratio between…

Cosmology and Nongalactic Astrophysics · Physics 2022-09-28 Guilherme Brando , Bartolomeo Fiorini , Kazuya Koyama , Hans A. Winther

Although consensus seems to exist about the validity of equations accounting for radiation reaction in curved space-time, their previous derivations were criticized recently as not fully satisfactory: some ambiguities were noticed in the…

General Relativity and Quantum Cosmology · Physics 2016-11-09 Dmitri Gal'tsov , Pavel Spirin , Simona Staub

Models that seek to explain cosmic acceleration through modifications to General Relativity (GR) evade stringent Solar System constraints through a restoring, screening mechanism. Down-weighting the high density, screened regions in favor…

Cosmology and Nongalactic Astrophysics · Physics 2018-01-30 Georgios Valogiannis , Rachel Bean

Extended theories of gravity have been extensively investigated during the last thirty years, aiming at fixing infrared and ultraviolet shortcomings of General Relativity and of the associated $\Lambda$CDM cosmological model. Recently,…

General Relativity and Quantum Cosmology · Physics 2022-08-10 Filippo Bouchè , Salvatore Capozziello , Vincenzo Salzano , Keiichi Umetsu

Using Subaru Hyper Suprime-Cam (HSC) year 1 data, we perform the first $k$-cut cosmic shear analysis constraining both $\Lambda$CDM and $f(R)$ Hu-Sawicki modified gravity. To generate the $f(R)$ cosmic shear theory vector, we use the matter…

Cosmology and Nongalactic Astrophysics · Physics 2021-10-22 Leah Vazsonyi , Peter L. Taylor , Georgios Valogiannis , Nesar S. Ramachandra , Agnès Ferté , Jason Rhodes

We employ a novel framework for accelerated cosmological inference, based on neural emulators and gradient-based sampling methods, to forecast constraints on dark energy models from Stage IV cosmic shear surveys. We focus on dark scattering…

Cosmology and Nongalactic Astrophysics · Physics 2025-04-23 Karim Carrion , Alessio Spurio Mancini , Davide Piras , Juan Carlos Hidalgo

We provide a cosmological test of modified gravity with two tensorial degrees of freedom and no extra propagating scalar mode. The theory of gravity we consider admits a cosmological model that is indistinguishable from the $\Lambda$CDM…

Cosmology and Nongalactic Astrophysics · Physics 2022-09-01 Takashi Hiramatsu , Tsutomu Kobayashi

We forecast the constraint on the Hu-Sawicki $f(R)$ model from the photometric survey operated by the Chinese Space Station Survey Telescope (CSST). The simulated $3\times2$pt data of galaxy clustering, weak lensing, and galaxy-galaxy…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-19 Jun-Hui Yan , Yan Gong , Qi Xiong , Xuelei Chen , Qi Guo , Ming Li , Yun Liu , Wenxiang Pei

We propose a simple and computationally fast method for performing N-body simulations for a large class of modified gravity theories with a screening mechanism such as chameleons, symmetrons and galileons. By combining the linear…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-22 Hans A. Winther , Pedro G. Ferreira

We look for exact solutions in scalar field cosmology. To achieve this we use $f(R)$ modified gravity with a scalar field and do not specify the the form of the $f(R)$ function. In particular, we study Friedmann universe assuming that…

General Relativity and Quantum Cosmology · Physics 2017-09-14 S. D. Maharaj , R. Goswami , S. V. Chervon , A. V. Nikolaev

Considering as usual that the underlying geometry of our universe is well described by the spatially flat Friedmann-Lemaitre-Robertson-Walker line element, we review how the background of holonomy corrected Loop Quantum Cosmology (LQC)…

General Relativity and Quantum Cosmology · Physics 2019-05-01 Jaume de Haro , Llibert Aresté Saló , Supriya Pan

Current constraints on gravity are relatively weak on galactic and intergalactic scales. Screened modified gravity models can exhibit complex behaviour there without violating stringent tests of gravity within our Solar System. They might…

Cosmology and Nongalactic Astrophysics · Physics 2018-08-15 Aneesh P. Naik , Ewald Puchwein , Anne-Christine Davis , Christian Arnold