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Recent analyses of the Master Type Ia supernova (SN Ia) sample have revealed a mild redshift dependence in the inferred local Hubble parameter, often expressed as tilde{H}_0(z) = H_0 (1+z)^{-\alpha}, where \alpha quantifies possible…

General Physics · Physics 2025-11-12 Seokcheon Lee

We study a cosmological model featuring evolutionary dark energy, according to the idea that the creation of its constituents arises from the gravitational field of the expanding universe, whose non-equilibrium physics is described by a…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-01 Iolanda Navone , Maria Giovanna Dainotti , Elisa Fazzari , Giovanni Montani , Naoto Maki , Kazunori Kohri

In this work, we investigate a cosmological scenario with a time-dependent cosmological constant $\Lambda$(t) within the spatially flat Friedmann-Lema\^itre-Robertson-Walker (FLRW) framework. Here we study a power-law $\Lambda(t)$CDM model…

General Relativity and Quantum Cosmology · Physics 2025-10-28 Archana Dixit , Manish Yadav , Anirudh Pradhan , M. S. Barak

We analyze a model for Dark Energy - Dark Matter interaction, based on a decaying process of the former into the latter. The dynamical equations are constructed following a kinetic formulation, which separates the interacting fluctuations…

General Relativity and Quantum Cosmology · Physics 2025-02-24 Giovanni Montani , Nakia Carlevaro , Luis A. Escamilla , Eleonora Di Valentino

A matter-coupled scalar field model is presented in obtaining a scalar fifth force when the constraint of the current cosmological constant is satisfied. The interaction potential energy density between the scalar field and matter has a…

General Relativity and Quantum Cosmology · Physics 2020-04-22 Hai-Chao Zhang

Model-independent bounds on the Hubble constant $H_0$ are important to shed light on cosmological tensions. We work out a model-independent analysis based on the sum rule, which is applied to late- and early-time data catalogs to determine…

Cosmology and Nongalactic Astrophysics · Physics 2025-09-17 Orlando Luongo , Marco Muccino

We show that the $H_0$ tension can be alleviated in the framework of Horndeski/generalized galileon gravity. In particular, since the terms depending on $G_5$ control the friction in the Friedmann equation, we construct specific sub-classes…

General Relativity and Quantum Cosmology · Physics 2023-01-11 Maria Petronikolou , Spyros Basilakos , Emmanuel N. Saridakis

Forthcoming surveys will extend the understanding of cosmological large scale structures up to unprecedented redshift. According to this perspective, we present a fully relativistic framework to evaluate the impact of stochastic…

Cosmology and Nongalactic Astrophysics · Physics 2021-10-04 Giuseppe Fanizza , Bartolomeo Fiorini , Giovanni Marozzi

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

Current measurements of the Hubble constant $H_0$ on scale less than $\sim100$ Mpc appear to be controversial, while the observations made at high redshift seem to provide a relatively low value. On the other hand, the Hubble expansion is…

Astrophysics · Physics 2009-10-28 Xiang-Ping Wu , Bo Qin , Li-Zhi Fang

We present the idea that replacing the cosmological constant $\Lambda$ in the $\Lambda$CDM model by a distribution of walls, with very low tension compared to what one would expect from new physics, could help explaining the tension in the…

Cosmology and Nongalactic Astrophysics · Physics 2024-06-13 Colin D. Froggatt , Holger Bech Nielsen

The tension between measurements of the Hubble constant $H_0$ locally and the value inferred from Planck satellite have provided a strong motivation to explore theoretical frameworks beyond the standard cosmological model ($\Lambda$CDM). To…

General Relativity and Quantum Cosmology · Physics 2025-08-29 R. Mohebi , Kh. Saaidi T. Golanbari , K. Karami

The Hubble parameter is a critical measurement in cosmology, which contains the most direct information of the cosmic expansion history. Since discrepancy is found between low redshift and high redshift estimations of Hubble constant, we…

Cosmology and Nongalactic Astrophysics · Physics 2014-10-02 Jiaxin Wang , Xinhe Meng

The Hubble constant, $H_0$, tension is the tension among the local probes, Supernovae Ia, and the Cosmic Microwave Background Radiation. It has been almost a decade, and this tension still puzzles the community. Here, we add intermediate…

High Energy Astrophysical Phenomena · Physics 2024-07-18 Shahnawaz A. Adil , Maria G. Dainotti , Anjan A. Sen

The Universe may feature large-scale inhomogeneities beyond the standard paradigm, implying that statistical homogeneity and isotropy may be reached only on much larger scales than the usually assumed $\sim$100 Mpc. This means that we are…

Cosmology and Nongalactic Astrophysics · Physics 2022-09-05 David Camarena , Valerio Marra , Ziad Sakr , Chris Clarkson

The rate at which the universe is expanding today is a fundamental parameter in cosmology which governs our understanding of structure formation and dark energy. However, current measurements of the Hubble constant, $H_0$, show a…

Cosmology and Nongalactic Astrophysics · Physics 2020-06-02 Carlos A. P. Bengaly , Chris Clarkson , Roy Maartens

Recently released Planck data favor a lower value of the Hubble constant and a higher value of the fraction matter density in the standard $\Lambda$CDM model, which are discrepant with some of the low-redshift measurements. Within the…

Cosmology and Nongalactic Astrophysics · Physics 2014-07-23 Rong-Gen Cai , Zong-Kuan Guo , Bo Tang

A substantial body of phenomenological and theoretical work over the last few years strengthens the possibility that the vacuum energy density (VED) of the universe is dynamical, and in particular that it adopts the `running vacuum model'…

Cosmology and Nongalactic Astrophysics · Physics 2023-05-31 Joan Sola Peracaula , Adria Gomez-Valent , Javier de Cruz Perez , Cristian Moreno-Pulido

The $\Lambda$CDM model provides a good fit to a large span of cosmological data but harbors areas of phenomenology. With the improvement of the number and the accuracy of observations, discrepancies among key cosmological parameters of the…

Cosmology and Nongalactic Astrophysics · Physics 2021-07-14 Eleonora Di Valentino , Olga Mena , Supriya Pan , Luca Visinelli , Weiqiang Yang , Alessandro Melchiorri , David F. Mota , Adam G. Riess , Joseph Silk

The fundamental laws of physics are required to be invariant under local spatial scale change. In 3-dimensional space, this leads to a variation in Planck constant \hbar and speed of light c. They vary as \hbar ~ a^(1/2) and c ~ a^(-1/2), a…

General Physics · Physics 2013-02-28 Hoang K. Nguyen