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Related papers: Alternatives to $\Lambda$: Torsion, Generalized Co…

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In this work, we have considered a model independent approach to study the nature of the late time cosmic acceleration. We have used the Pade approximation to parametrize the comoving distance. Consequently, from this comoving distance, we…

Cosmology and Nongalactic Astrophysics · Physics 2020-01-09 Bikash R. Dinda

We discuss the connection among three distinct classes of models often used to explain the late cosmic acceleration: decaying cosmological term, bulk viscous pressure, and nonlinear fluids. We focus on models that are equivalent at zeroth…

Astrophysics · Physics 2007-05-23 Sandro Silva e Costa , Martin Makler

The current standard model of cosmology, the LambdaCDM model, is based on the homogeneous FLRW solutions of the Einstein equations to which some perturbations are added to account for the CMB features and structure formation at large…

Cosmology and Nongalactic Astrophysics · Physics 2012-03-14 Marie-Noëlle Célérier

Attempts at constraining theories of late time accelerated expansion often assume broad priors for the parameters in their phenomenological description. Focusing on shift-symmetric scalar-tensor theories with standard gravitational wave…

Cosmology and Nongalactic Astrophysics · Physics 2021-10-28 Dina Traykova , Emilio Bellini , Pedro G. Ferreira , Carlos García-García , Johannes Noller , Miguel Zumalacárregui

We present measurements of the spatial clustering statistics in redshift space of various scalar field modified gravity simulations. We utilise the two-point and the three-point correlation functions to quantify the spatial distribution of…

Cosmology and Nongalactic Astrophysics · Physics 2016-07-20 Cristiano G. Sabiu , David F. Mota , Claudio Llinares , Changbom Park

This paper explores models of the FLRW universe that incorporate a time-varying cosmological term $\Lambda(t)$. Specifically, we assume a power-law form for the cosmological term as a function of the scale factor: $\Lambda(t)=\Lambda_{0}…

Cosmology and Nongalactic Astrophysics · Physics 2024-05-14 M. Koussour , N. Myrzakulov , J. Rayimbaev

We carry out an analysis of the cosmological perturbations in general relativity for three different models which are good candidates to describe the current acceleration of the Universe. These three set-ups are described classically by…

Cosmology and Nongalactic Astrophysics · Physics 2017-05-31 Imanol Albarran , Mariam Bouhmadi-López , João Morais

There has been much debate over whether or not one could explain the observed acceleration of the Universe with inhomogeneous cosmological models, such as the spherically-symmetric Lemaitre-Tolman-Bondi (LTB) models. It has been claimed…

Astrophysics · Physics 2009-11-11 R. Ali Vanderveld , Eanna E. Flanagan , Ira Wasserman

We study flat Friedmann-Lemaitre-Robertson-Walker cosmological models for a scalar field coupled nonminimally to teleparallel gravity with generic coupling and potential functions. The goal of this paper is to determine the conditions under…

General Relativity and Quantum Cosmology · Physics 2016-08-08 Laur Jarv , Alexey Toporensky

The phenomenon of emergent physics in condensed-matter many-body systems has become the paradigm of modern physics, and can probably also be applied to high-energy physics and cosmology. This encouraging fact comes from the universal…

Strongly Correlated Electrons · Physics 2009-11-11 G. E. Volovik

The observational evidence for the acceleration of the universe demonstrates that canonical theories of gravitation and particle physics are incomplete, if not incorrect. A new generation of astronomical facilities will shortly be able to…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 C. J. A. P. Martins

Our fundamental lack of understanding of the acceleration of the Universe suggests that we consider a kinematic description. The simplest formalism involves the third derivative of the scale factor through a jerk parameter. A new approach…

Astrophysics · Physics 2007-05-23 R. D. Blandford , M. Amin , E. A. Baltz , K. Mandel , P. J. Marshall

In this work, we studied four types of cosmological models with different mechanisms driving the accelerated expansion of the universe, include Braneworld models, Chaplygin Gas models, Emergent Dark Energy models, and cosmological torsion…

Cosmology and Nongalactic Astrophysics · Physics 2024-05-02 Ziqiang Liu , Tonghua Liu , Xinyi Zhong , Yifei Xu , Xiaogang Zheng

Through likelihood analyses of both current and future data that constrain both the expansion history of the universe and the clustering of matter fluctuations, we provide falsifiable predictions for three broad classes of models that…

Cosmology and Nongalactic Astrophysics · Physics 2018-09-18 V Miranda , Cora Dvorkin

Recently, in [1], we presented the first combined non-parametric reconstruction of the three time-dependent functions that capture departures from the standard cosmological model, $\Lambda$CDM, in the expansion history and gravitational…

Cosmology and Nongalactic Astrophysics · Physics 2023-03-08 Marco Raveri , Levon Pogosian , Matteo Martinelli , Kazuya Koyama , Alessandra Silvestri , Gong-Bo Zhao

Late time cosmic acceleration may be achieved by modifying gravity on large scales. This should also have consequences on the evolution of perturbations. We thus extend our study of exponential infrared $f(T)$ teleparallel gravity to…

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

The recent observational data in cosmology seem to indicate that the universe is currently expanding in an accelerated way. An intriguing interpretation of these data is that they may just be signalling that Einstein's General Relativity is…

High Energy Physics - Theory · Physics 2018-05-18 Fulvio Sbisà

It is a very well established matter nowadays that many modified gravity models can offer a sound alternative to General Relativity for the description of the accelerated expansion of the universe. But it is also equally well known that no…

Cosmology and Nongalactic Astrophysics · Physics 2018-03-16 Ruth Lazkoz , María Ortiz-Baños , Vincenzo Salzano

In this work, we carry out a comprehensive perturbative analysis of four cosmological models featuring a sign-switching cosmological constant. Among these, we include the well-known $\Lambda_{\rm s}$CDM model, characterised by an abrupt…

General Relativity and Quantum Cosmology · Physics 2025-10-13 Mariam Bouhmadi-López , Beñat Ibarra-Uriondo

The cosmographic approach, which only relies upon the homogeneity and isotropy of the Universe on large scales, has become an essential tool in dealing with an increasing number of theoretical possibilities for explaining the late-time…

General Relativity and Quantum Cosmology · Physics 2016-04-26 Alvaro de la Cruz-Dombriz