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We study the implications of a combined analysis of cosmic standard candles and standard rulers on the viability of cosmological models beyond the cosmological concordance model. To this end, we employ well-established data in the form of…

Cosmology and Nongalactic Astrophysics · Physics 2020-10-19 Manfred Lindner , Kevin Max , Moritz Platscher , Jonas Rezacek

The fundamental constants at recombination can differ from their present-day values due to degeneracies in cosmological parameters, raising the possibility of yet-undiscovered physics coupled directly to the Standard Model. We study the…

Cosmology and Nongalactic Astrophysics · Physics 2025-08-20 Masha Baryakhtar , Olivier Simon , Zachary J. Weiner

Linear cosmological perturbations of a large class of modified gravity and dark energy models can be unified in the effective field theory of cosmic acceleration, encompassing Horndeski scalar-tensor theories and beyond. The fully available…

Cosmology and Nongalactic Astrophysics · Physics 2015-11-25 Lucas Lombriser , Andy Taylor

The primary purpose of this work is the provision of accurate, analytic, evolutionary templates for cosmological parameters and fundamental constants in a dynamical cosmology. A flat quintessence cosmology with a dark energy potential that…

Cosmology and Nongalactic Astrophysics · Physics 2023-05-17 Rodger I. Thompson

We present cosmo_learn, an open-source python-based software package designed to simulate cosmological data and perform data-driven inference using a range of modern statistical and machine learning techniques. Motivated by the growing…

Cosmology and Nongalactic Astrophysics · Physics 2025-08-29 Reginald Christian Bernardo , Daniela Grandón , Jackson Levi Said , Víctor H. Cárdenas , Gene Carlo Belinario , Reinabelle Reyes

Modified gravity theories may provide an alternative to dark energy to explain cosmic acceleration. We argue that the observational program developed to test dark energy needs to be augmented to capture new tests of gravity on astrophysical…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Bhuvnesh Jain

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

Decaying Dark Energy models modify the background evolution of the most common observables, such as the Hubble function, the luminosity distance and the Cosmic Microwave Background temperature-redshift scaling relation. We use the most…

Cosmology and Nongalactic Astrophysics · Physics 2018-09-05 Ivan de Martino

One of the main science goals of the Large Synoptic Survey Telescope (LSST) is to uncover the nature of cosmic acceleration. In the base analysis, possible deviations from the Lambda-Cold-Dark-Matter ($\Lambda$CDM) background evolution will…

Testing gravity and the concordance model of cosmology, $\Lambda$CDM, at large scales is a key goal of this decade's largest galaxy surveys. Here we present a comparative study of dark matter power spectrum predictions from different…

I review a class of nonlocally modified gravity models which were proposed to explain the current phase of cosmic acceleration without dark energy. Among the topics considered are deriving causal and conserved field equations, adjusting the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-18 R. P. Woodard

In this work we present 21cmFirstCLASS, a modified version of 21cmFAST, the most popular code in the literature for computing the anisotropies of the 21-cm signal. Our code uses the public cosmic microwave background (CMB) Boltzmann code…

Cosmology and Nongalactic Astrophysics · Physics 2024-05-29 Jordan Flitter , Ely D. Kovetz

In this work, a new generic parameterisation for $f(R)$ theories is presented. Our proposal for a new equation of state can reproduce an $f(R)$-like evolution that describes late and early time universe within 1-$\sigma$ C.L when we use a…

General Relativity and Quantum Cosmology · Physics 2020-11-20 N. M. Jiménez Cruz , Celia Escamilla-Rivera

Cosmology is living through fascinating times, where new observations from ground and space telescopes are questioning the established paradigm, the so-called Lambda Cold Dark Matter model. The particle nature of Dark Matter is severely…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-15 Juan Garcia-Bellido

Modified gravity theories are a popular alternative to dark energy as a possible explanation for the observed accelerating cosmic expansion, and their cosmological tests are currently an active research field. Studies in recent years have…

Cosmology and Nongalactic Astrophysics · Physics 2016-10-12 Juan J. Ceron-Hurtado , Jian-hua He , Baojiu Li

This study forges new tools to discriminate between dynamical and static dark energy. It provides accurate evolutionary templates of dynamical cosmological parameters and fundamental constants as analytic functions of the scale factor. They…

Cosmology and Nongalactic Astrophysics · Physics 2022-04-06 Rodger I. Thompson

A novel routine to investigate the scalar fields in a cosmological context is discussed in the framework of the Hamiltonian formalism. Starting from the Einstein-Hilbert action coupled to a Lagrangian density that contains two components -…

General Relativity and Quantum Cosmology · Physics 2013-09-16 Alex E. Bernardini , O. Bertolami

Our ignorance about the source of cosmic acceleration has stimulated study of a wide range of models and modifications to gravity. Cosmological scaling solutions in any of these theories are privileged because they represent natural…

High Energy Physics - Theory · Physics 2008-11-26 Shinji Tsujikawa , M. Sami

Higher order curvature gravity has recently received a lot of attention due to the fact that it gives rise to cosmological models which seem capable of solving dark energy and quintessence issues without using "ad hoc" scalar fields. Such…

Astrophysics · Physics 2014-10-13 S. Capozziello , V. F. Cardone , S. Carloni , A. Troisi

We consider nonlinear redshift-dependent equation of state parameters as dark energy models in a spatially flat Friedmann-Lema\^itre-Robertson-Walker universe. To depict the expansion history of the universe in such cosmological scenarios,…

General Relativity and Quantum Cosmology · Physics 2018-02-06 Weiqiang Yang , Supriya Pan , Andronikos Paliathanasis