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Theories in which gravity is weaker on cosmological scales have been proposed to explain the observed acceleration of the universe. The nonlinear regime in such theories is not well studied, though it is likely that observational tests of…

Astrophysics · Physics 2009-11-11 Hans F. Stabenau , Bhuvnesh Jain

Gravitational lensing is a crucial tool for exploring cosmic phenomena, providing insights into galaxy clustering, dark matter, and dark energy. Given the substantial computational demands of $N$-body simulations, approximate methods like…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-31 Viviane Alfradique , Tiago Castro , Valerio Marra , Miguel Quartin , Carlo Giocoli , Pierluigi Monaco

Accurate predictions for the non-linear matter power spectrum are needed to confront theory with observations in current and near future weak lensing and galaxy clustering surveys. We propose a computationally cheap method to create an…

Cosmology and Nongalactic Astrophysics · Physics 2020-01-01 Hans Winther , Santiago Casas , Marco Baldi , Kazuya Koyama , Baojiu Li , Lucas Lombriser , Gong-Bo Zhao

Modified gravity models with screening in local environments appear in three different guises: chameleon, K-mouflage and Vainshtein mechanisms. We propose to look for differences between these classes of models by considering cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2015-10-28 Philippe Brax , Anne-Christine Davis

We use N-body simulation to study the structure formation in the Cubic Galileon Gravity model where along with the usual kinetic and potential term we also have a higher derivative self-interaction term. We find that the large scale…

Cosmology and Nongalactic Astrophysics · Physics 2020-08-12 Jiajun Zhang , Bikash R. Dinda , Md. Wali Hossain , Anjan A. Sen , Wentao Luo

We study the stability of the Vainshtein screening solution of the massive/bi-gravity based on the massive nonlinear sigma model as the effective action inside the Vainshtein radius. The effective action is obtained by taking the…

High Energy Physics - Theory · Physics 2016-09-30 Katsuki Aoki , Shuntaro Mizuno

We present a formalism to study screening mechanisms in modified theories of gravity via perturbative methods in different cosmological scenarios. We consider Einstein frame posed theories that are recast as Jordan frame theories, where a…

Cosmology and Nongalactic Astrophysics · Physics 2019-01-30 Alejandro Aviles , Jorge L. Cervantes-Cota , David F. Mota

We extend the scale-dependent Gaussian Streaming Model (GSM) to produce analytical predictions for the anisotropic redshift-space correlation function for biased tracers in modified gravity models. Employing the Convolution Lagrangian…

Cosmology and Nongalactic Astrophysics · Physics 2020-02-03 Georgios Valogiannis , Rachel Bean , Alejandro Aviles

Geometry optimization is an important part of both computational materials and surface science because it is the path to finding ground state atomic structures and reaction pathways. These properties are used in the estimation of…

Materials Science · Physics 2021-07-07 Yilin Yang , Omar A. Jimenez-Negron , John R. Kitchin

We describe in detail the general methodology and numerical implementation of consistent N-body simulations for coupled scalar field cosmological models, including the background cosmology and the generation of initial conditions (with the…

Cosmology and Nongalactic Astrophysics · Physics 2012-07-04 Baojiu Li , John D. Barrow

Coarse grid projection (CGP) is a multiresolution technique for accelerating numerical calculations associated with a set of nonlinear evolutionary equations along with the stiff Poisson equations. In this article we use CGP for the first…

Computational Physics · Physics 2020-03-03 Ali Kashefi

This paper presents a novel neural network training approach for faster convergence and better generalization abilities in deep reinforcement learning. Particularly, we focus on the enhancement of training and evaluation performance in…

Machine Learning · Computer Science 2020-05-26 Mohammed Sharafath Abdul Hameed , Gavneet Singh Chadha , Andreas Schwung , Steven X. Ding

Modified gravity models require a screening mechanism to be able to evade the stringent constraints from local gravity experiments and, at the same time, give rise to observable astrophysical and cosmological signatures. Such screened…

Cosmology and Nongalactic Astrophysics · Physics 2015-11-04 Max Gronke , David F. Mota , Hans A. Winther

Screened modified gravity (SMG) is a kind of scalar-tensor theory with screening mechanisms, which can suppress the fifth force in dense regions and allow theories to evade the solar system and laboratory tests. In this paper, we…

General Relativity and Quantum Cosmology · Physics 2017-05-23 Xing Zhang , Tan Liu , Wen Zhao

We present a formalism to calculate the non-linear matter power spectrum in modified gravity models that explain the late-time acceleration of the Universe without dark energy. Any successful modified gravity models should contain a…

Cosmology and Nongalactic Astrophysics · Physics 2009-08-03 Kazuya Koyama , Atsushi Taruya , Takashi Hiramatsu

We investigate the viability of producing galaxy mock catalogues with COmoving Lagrangian Acceleration (COLA) simulations in Modified Gravity (MG) models employing the Halo Occupation Distribution (HOD) formalism. In this work, we focus on…

Cosmology and Nongalactic Astrophysics · Physics 2021-09-20 Bartolomeo Fiorini , Kazuya Koyama , Albert Izard , Hans A. Winther , Bill S. Wright , Baojiu Li

At early times dark matter has a thermal velocity dispersion of unknown amplitude which, for warm dark matter models, can influence the formation of nonlinear structure on observable scales. We propose a new scheme to simulate cosmologies…

Cosmology and Nongalactic Astrophysics · Physics 2020-06-10 Jens Stücker , Oliver Hahn , Raul E. Angulo , Simon D. M. White

Modifications of gravity have been considered to model the primordial inflation and the late-time cosmic acceleration. Provided that modified gravity models do not suffer from theoretical instabilities, they must be confronted with…

General Relativity and Quantum Cosmology · Physics 2016-10-13 Sandrine Schlögel

Reliable analytical modeling of the non-linear power spectrum (PS) of matter perturbations is among the chief pre-requisites for cosmological analyses from the largest sky surveys. This is especially true for the models that extend the…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-10 Suhani Gupta , Wojciech A. Hellwing , Maciej Bilicki

We examine the efficacy of the halo mass function as a probe of $f(R)$, symmetron and DGP gravity. We develop an excursion-set method to generalise a range of popular HMF fitting functions from GR to screened MG, considering the HMF…

Cosmology and Nongalactic Astrophysics · Physics 2018-12-26 Francesca von Braun-Bates , Julien Devriendt
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