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We study observational signatures of non-gravitational interactions between the dark components of the cosmic fluid, which can be either due to creation of dark particles from the expanding vacuum or an effect of the clustering of a…

Cosmology and Nongalactic Astrophysics · Physics 2019-12-10 Micol Benetti , Welber Miranda , Humberto A. Borges , Cassio Pigozzo , Saulo Carneiro , Jailson S. Alcaniz

This study investigates the potential of a cosmological model termed $\Lambda w$DM, in which a cosmological constant play the role of dark energy and dark matter is barotropic and has a constant equation of state parameter ($w_{\rm dm}$),…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-02 Yan-Hong Yao , Jian-Qi Liu

In order to deal with a large cosmological constant a relaxation mechanism based on modified gravity has been proposed recently. By virtue of this mechanism the effect of the vacuum energy density of a given quantum field/string theory (no…

General Relativity and Quantum Cosmology · Physics 2012-01-31 Spyros Basilakos , Florian Bauer , Joan Sola

The $\Lambda$CDM framework offers a remarkably good description of our universe with a very small number of free parameters, which can be determined with high accuracy from currently available data. However, this does not mean that the…

Cosmology and Nongalactic Astrophysics · Physics 2015-07-22 Yves Zolnierowski , Alain Blanchard

We use observations related to the variation of fundamental constants, in order to impose constraints on the viable and most used $f(T)$ gravity models. In particular, for the fine-structure constant we use direct measurements obtained by…

General Relativity and Quantum Cosmology · Physics 2017-04-18 Rafael C. Nunes , Alexander Bonilla , Supriya Pan , Emmanuel N. Saridakis

Cosmological observables could be used to construct cosmological models, however, a fixed number of observables limited on the light cone is not enough to uniquely determine a certain model. A reconstructed spherically symmetric,…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Siqi Liu , Tong-Jie Zhang

We suggest an alternative framework for interpreting the current state of the visible universe. Our approach is based on a dynamical ``Cosmological Constant'' and the starting point is that a decaying vacuum produces matter. As we point…

Astrophysics · Physics 2014-10-13 Manasse R. Mbonye

Gravitational lensing information from the two and higher point statistics of the CMB temperature and polarization fields are intrinsically correlated because they are lensed by the same realization of structure between last scattering and…

Cosmology and Nongalactic Astrophysics · Physics 2017-03-01 Pavel Motloch , Wayne Hu , Aurélien Benoit-Lévy

We consider a quintessence field which transitions from a matter-like to a cosmological constant behavior between recombination and the present time. We aim at easing the tension in the measurement of the present Hubble rate, and we assess…

Cosmology and Nongalactic Astrophysics · Physics 2019-09-24 Eleonora Di Valentino , Ricardo Z. Ferreira , Luca Visinelli , Ulf Danielsson

In the present work we analyze and compare the information coming from different observational data sets in the context of a sort of f(T) theories. We perform a joint analysis with measurements of the most recent type Ia supernovae (SNe…

Cosmology and Nongalactic Astrophysics · Physics 2011-01-27 Gabriel R. Bengochea

The decaying vacuum model (DV), treating dark energy as a varying vacuum, has been studied well recently. The vacuum energy decays linearly with the Hubble parameter in the late-times, $\rho_\Lambda(t) \propto H(t)$, and produces the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 M. L. Tong , H. Noh

We use the physically-consistent tilted spatially-flat and untilted non-flat $\Lambda$CDM inflation models to constrain cosmological parameter values with the Planck 2015 cosmic microwave background (CMB) anisotropy data and recent Type Ia…

Cosmology and Nongalactic Astrophysics · Physics 2019-09-19 Chan-Gyung Park , Bharat Ratra

We examine the dark energy and matter densities allowed by precision measurements of distances out to various redshifts, in the presence of spatial curvature and (near) arbitrary behavior of the dark energy equation of state. Degeneracies…

Cosmology and Nongalactic Astrophysics · Physics 2011-09-22 Arman Shafieloo , Eric V. Linder

The $\Lambda$CDM model faces several tensions with recent cosmological data and their increased accuracy. The mismatch between the values of the Hubble constant $H_0$ obtained from direct distance ladder measurements and from the cosmic…

Cosmology and Nongalactic Astrophysics · Physics 2024-05-03 Alain Blanchard , Jean-Yves Héloret , Stéphane Ilić , Brahim Lamine , Isaac Tutusaus

We show that a combined analysis of CMB anisotropy power spectra obtained by the Planck satellite and luminosity distance data simultaneously excludes a flat universe and a cosmological constant at $99 \%$ CL. These results hold separately…

Cosmology and Nongalactic Astrophysics · Physics 2021-02-17 Eleonora Di Valentino , Alessandro Melchiorri , Joseph Silk

The search for the physical mechanism underlying the observational evidence for the acceleration of the recent universe is a compelling goal of modern fundamental cosmology. Here we quantitatively study a class of homogeneous and isotropic…

Cosmology and Nongalactic Astrophysics · Physics 2022-04-19 E. -A. Kolonia , C. J. A. P. Martins

We use updated Hubble parameter and baryon acoustic oscillation data, as well as other lower-redshift Type Ia supernova, Mg II reverberation-measured quasar, quasar angular size, H II starburst galaxy, and Amati-correlated gamma-ray burst…

Cosmology and Nongalactic Astrophysics · Physics 2022-05-31 Shulei Cao , Bharat Ratra

We investigate an extension of the $\Lambda$CDM model where the dark matter (DM) is coupled to photons, inducing a nonconservation of the numbers of particles for both species, where the DM particles are allowed to dilute throughout the…

Cosmology and Nongalactic Astrophysics · Physics 2018-08-21 Suresh Kumar , Rafael C. Nunes , Santosh Kumar Yadav

In this paper, we perform a forecast analysis to test the capacity of future baryon acoustic oscillation (BAO) and cosmic microwave background (CMB) experiments to constrain phenomenological interacting dark energy models using the Fisher…

Cosmology and Nongalactic Astrophysics · Physics 2017-11-23 Larissa Santos , Wen Zhao , Elisa G. M. Ferreira , Jerome Quintin

In this work we examine what are the cosmological implications of allowing the geometrical curvature density to behave independently from the energy density contents. Using the full data extracted by Planck mission from CMB, combined with…

General Relativity and Quantum Cosmology · Physics 2017-10-02 Ziad Sakr , Alain Blanchard
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