English
Related papers

Related papers: Constraints on prospective deviations from the col…

200 papers

In this work, two different models, one with cosmological constant $\Lambda$, and baryonic and dark matter (with $\omega_{dm} \neq 0$), and the other with an $X$ dark energy (with $\omega_{de} \neq -1$), and baryonic and dark matter (with…

Cosmology and Nongalactic Astrophysics · Physics 2021-04-05 Emilio Elizalde , Janusz Gluza , Martiros Khurshudyan

The $H_{0}$ tension problem is studied in the light of a matter creation mechanism (an effective approach to replacing dark energy), the way to define the matter creation rate being of pure phenomenological nature. Bayesian (probabilistic)…

General Relativity and Quantum Cosmology · Physics 2024-07-31 Emilio Elizalde , Martiros Khurshudyan , Sergei D. Odintsov

The quintessence dark energy potential is reconstructed in a model-independent way. Reconstruction relies on a Gaussian process and on available expansion-rate data. Specifically, 40-point values of $H(z)$ are used, consisting of a 30-point…

General Relativity and Quantum Cosmology · Physics 2022-03-15 Emilio Elizalde , Martiros Khurshudyan , K. Myrzakulov , S. Bekov

Bayesian (Probabilistic) Machine Learning is used to probe the opacity of the Universe. It relies on a generative process where the model is the key object to generate the data involving the unknown parameters of the model, our prior…

Cosmology and Nongalactic Astrophysics · Physics 2020-08-17 Emilio Elizalde , Martiros Khurshudyan

The goal of this paper is to study new cosmological models where the dark energy is a varying Chaplygin gas. This specific dark energy model with non-linear EoS had been often discussed in modern cosmology. Contrary to previous studies, we…

General Relativity and Quantum Cosmology · Physics 2021-05-04 M. Khurshudyan , R. Myrzakulov

In this paper, two inhomogeneous single fluid models for the Universe, which are able to naturally solve the $H_{0}$ tension problem, are discussed. The analysis is based on a Bayesian Machine Learning approach that uses a generative…

General Relativity and Quantum Cosmology · Physics 2020-12-09 Emilio Elizalde , Martiros Khurshudyan , Sergei D. Odintsov , Ratbay Myrzakulov

An important issue in cosmology is reconstructing the effective dark energy equation of state directly from observations. With few physically motivated models, future dark energy studies cannot only be based on constraining a dark energy…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Marina Seikel , Chris Clarkson , Mathew Smith

Constraints on a dark energy dominated Universe are obtained from an interplay between Bayesian Machine Learning and string Swampland criteria. The approach here differs from previous studies, since in the generative process Swampland…

General Relativity and Quantum Cosmology · Physics 2021-05-05 Emilio Elizalde , Martiros Khurshudyan

In this paper, the implications of string Swampland criteria for a dark energy-dominated universe, where we have a deviation from the cold dark matter model, will be discussed. In particular, we have considered two models. One of them is…

General Relativity and Quantum Cosmology · Physics 2023-08-03 Martiros Khurshudyan

The possible slowing down of cosmic acceleration was widely studied. However, the imposition of dark energy parametrization brought some tensions. In our recent paper, we test this possibility using a model-independent method, Gaussian…

Cosmology and Nongalactic Astrophysics · Physics 2018-04-04 Ming-Jian Zhang , Jun-Qing Xia

We investigate an extended cosmological model motivated by the asymptotic safety of gravitational field theory, in which the matter and radiation densities and the cosmological constant receive a correction parametrized by the parameters…

Cosmology and Nongalactic Astrophysics · Physics 2021-07-07 Li-Yang Gao , Ze-Wei Zhao , She-Sheng Xue , Xin Zhang

We investigate deviations from the cosmic distance duality relation adopting model-dependent and -independent approaches using i) a Taylor expansion, ii) a power-law parameterization, iii) a logarithmic correction, iv) a (2;1) Pad\'e…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-05 Anna Chiara Alfano

In this paper, we investigate the process in which axion dark matter undergoes thermal friction, resulting in energy injection into dark radiation, with the aim of mitigating the Hubble tension and large-scale structure tension. In the…

Cosmology and Nongalactic Astrophysics · Physics 2024-05-17 Gang Liu , Yuhao Mu , Zhihuan Zhou , Lixin Xu

In the present work we analyze two different models of interaction between dark energy and dark matter, also known as vacuum decay models or $\Lambda(t)$CDM models. In both models, when the $H_0$ parameter is constrained by the Planck…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-23 L. S. Brito , J. F. Jesus , A. A. Escobal , S. H. Pereira

One of the key issues in cosmology is to establish the nature of dark energy, and to determine whether the equation of state evolves with time. When estimating this from distance measurements there is a degeneracy with the matter density.…

Cosmology and Nongalactic Astrophysics · Physics 2016-05-23 Vinicius C. Busti , Chris Clarkson

Gaussian processes (GP) provide an elegant and model-independent method for extracting cosmological information from the observational data. In this work, we employ GP to perform a joint analysis by using the geometrical cosmological probes…

Cosmology and Nongalactic Astrophysics · Physics 2021-02-11 Alexander Bonilla , Suresh Kumar , Rafael C. Nunes

The Hubble tension between the $\Lambda$CDM-model-dependent prediction of the current expansion rate $H_0$ using Planck data and direct, model-independent measurements in the local universe from the SH0ES collaboration disagree at…

Cosmology and Nongalactic Astrophysics · Physics 2020-07-14 Kanhaiya L. Pandey , Tanvi Karwal , Subinoy Das

Decaying dark matter models generically modify the equation of state around the time of dark matter decay, and this in turn modifies the expansion rate of the Universe through the Friedmann equation. Thus, a priori, these models could solve…

Cosmology and Nongalactic Astrophysics · Physics 2023-07-04 Andreas Nygaard , Emil Brinch Holm , Thomas Tram , Steen Hannestad

In the present paper, we investigate the dark energy equation of state using the Gaussian processes analysis method, without confining a particular parametrization. The reconstruction is carried out by adopting the background data including…

Cosmology and Nongalactic Astrophysics · Physics 2018-06-11 Ming-Jian Zhang , Hong Li

Current tensions in cosmology, including $H_0$ and $\sigma_8$, provide one of the strong reasons to suspect the existence of physics beyond the standard model of cosmology ($\Lambda$CDM). In this paper, we investigate if there is a relation…

Cosmology and Nongalactic Astrophysics · Physics 2022-08-31 Zahra Davari , Nima Khosravi
‹ Prev 1 2 3 10 Next ›