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A cosmological model in an Einstein-Cartan framework endowed with torsion is studied. For a torsion function assumed to be proportional to Hubble expansion function, namely $\phi=-\alpha H$, the contribution of torsion function as a dark…

General Relativity and Quantum Cosmology · Physics 2022-04-27 S. H. Pereira , A. M. Vicente , J. F. Jesus , R. F. L. Holanda

The paper studies different observational features in the case of a specific cubic gravity theory, based on third order contractions of the Riemann tensor. Considering viable cosmic chronometers data, baryon acoustic oscillations, and…

General Relativity and Quantum Cosmology · Physics 2023-11-21 Mihai Marciu , Dana Maria Ioan , Mihai Dragomir

Complimenting recent work on the effective field theory of cosmological large scale structures, here we present detailed approximate analytical results and further pedagogical understanding of the method. We start from the collisionless…

Cosmology and Nongalactic Astrophysics · Physics 2014-04-02 Mark P. Hertzberg

An accurate modelling of baryonic feedback effects is required to exploit the full potential of future weak-lensing surveys such as Euclid or LSST. In this second paper in a series of two, we combine Euclid-like mock data of the cosmic…

We compare the cosmological first-order post-Newtonian (1PN) approximation with the relativistic cosmological linear perturbation theory in a zero-pressure medium with the cosmological constant. We compare equations and solutions in several…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 Hyerim Noh , Jai-chan Hwang

In this paper, convergence results on the solutions of a time and space discrete model approximation of the Boltzmann equation for a gas of Maxwellian particles in a bounded domain, obtained by Babovsky and Illner [1989], are extended to…

Numerical Analysis · Mathematics 2014-10-30 C. P. Grünfeld , D. Marinescu

The Lyman-$\alpha$ (Ly$\alpha$) three-dimensional correlation functions have been widely used to perform cosmological inference using the baryon acoustic oscillation (BAO) scale. While the traditional inference approach employs a data…

Cosmology and Nongalactic Astrophysics · Physics 2024-02-15 Francesca Gerardi , Andrei Cuceu , Benjamin Joachimi , Seshadri Nadathur , Andreu Font-Ribera

The coupled dark energy model provides a possible approach to mitigate the coincidence problem of cosmological standard model. Here, the coupling term is assumed as $\bar{Q}=3H\xi_x\bar{\rho}_x$, which is related to the interaction rate and…

Cosmology and Nongalactic Astrophysics · Physics 2016-10-11 Weiqiang Yang , Hang Li , Yabo Wu , Jianbo Lu

The Co-varying Physical Couplings (CPC) framework is a modified gravity set up assuming Einstein Field Equations wherein the quantities $\{G,c,\Lambda\}$ are promoted to space-time functions. Bianchi identity and the requirement of…

General Relativity and Quantum Cosmology · Physics 2022-09-15 R. R. Cuzinatto , R. P. Gupta , R. F. L. Holanda , J. F. Jesus , S. H. Pereira

We present a neural-network emulator for baryonic effects in the non-linear matter power spectrum. We calibrate this emulator using more than 50,000 measurements in a 15-dimensional parameters space, varying cosmology and baryonic physics.…

Cosmology and Nongalactic Astrophysics · Physics 2021-08-11 Giovanni Aricò , Raul E. Angulo , Sergio Contreras , Lurdes Ondaro-Mallea , Marcos Pellejero-Ibañez , Matteo Zennaro

There has been recent interest in the cosmological consequences of energy-momentum-powered gravity models, in which the matter side of Einstein's equations includes a term proportional to some power, $n$, of the energy-momentum tensor, in…

Cosmology and Nongalactic Astrophysics · Physics 2025-02-03 C. J. A. P. Martins , A. M. M. Vieira

We show that the widely used relaxation time approximation to the relativistic Boltzmann equation contains basic flaws, being incompatible with microscopic and macroscopic conservation laws. We propose a new approximation that fixes such…

Nuclear Theory · Physics 2021-07-28 Gabriel S. Rocha , Gabriel S. Denicol , Jorge Noronha

Known quantum and classical perturbative long-distance corrections to the Newton potential are extended into the short-distance regime using evolution equations for a `running' gravitational coupling, which is used to construct examples…

General Relativity and Quantum Cosmology · Physics 2021-08-24 Jan Smit

We consider the Einstein-Boltzmann system for massless particles in the Bianchi I space-time with scattering cross-sections in a certain range of soft potentials. We assume that the space-time has an initial conformal gauge singularity and…

General Relativity and Quantum Cosmology · Physics 2024-08-21 Ho Lee , Ernesto Nungesser , John Stalker , Paul Tod

The cosmic large-scale structure of our Universe is comprised of baryons and cold dark matter (CDM). Yet it is customary to treat these two components as a combined single-matter fluid with vanishing pressure, which is justified only for…

Cosmology and Nongalactic Astrophysics · Physics 2020-12-04 Cornelius Rampf , Cora Uhlemann , Oliver Hahn

We extend the Boltzmann equation in the relaxation time approximation to explicitly include transitions between particles forming an interacting mixture. Using the detailed balance condition as well as conditions of energy-momentum and…

High Energy Physics - Phenomenology · Physics 2020-12-23 Samapan Bhadury , Wojciech Florkowski , Amaresh Jaiswal , Radoslaw Ryblewski

Current and coming surveys will require sub-percent agreement in theoretical accuracy to test the different cosmological and gravity scenarios. This can be performed with Boltzmann solvers, i.e. codes that solve the linear evolution of…

Cosmology and Nongalactic Astrophysics · Physics 2020-10-13 Rubén Arjona

Maxwell-Amp\`{e}re-Nernst-Planck (MANP) equations were recently proposed to model the dynamics of charged particles. In this study, we enhance a numerical algorithm of this system with deep learning tools. The proposed hybrid algorithm…

Numerical Analysis · Mathematics 2023-12-12 Cheng Chang , Zhouping Xin , Tieyong Zeng

Atomic high-precision measurements have become a competitive and essential technique for tests of fundamental physics, the Standard Model, and our theory of gravity. It is therefore self-evident that such measurements call for a consistent…

Quantum Physics · Physics 2024-05-24 Tobias Asano , Enno Giese , Fabio Di Pumpo

This paper presents a systematic treatment of the linear theory of scalar gravitational perturbations in the synchronous gauge and the conformal Newtonian (or longitudinal) gauge. It differs from others in the literature in that we give, in…

Astrophysics · Physics 2015-06-24 Chung-Pei Ma , Edmund Bertschinger