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New measurements of the expansion rate of the Universe have plunged the standard model of cosmology into a severe crisis. In this letter, we propose a simple resolution to the problem that relies on a first order phase transition in a dark…

Cosmology and Nongalactic Astrophysics · Physics 2021-02-24 Florian Niedermann , Martin S. Sloth

Standard lore states that there is tension between the need to accommodate the relic density of a weakly interacting massive particle and direct searches for dark matter. However, the estimation of the relic density rests on an…

High Energy Physics - Phenomenology · Physics 2020-08-03 Dillon Berger , Seyda Ipek , Tim M. P. Tait , Michael Waterbury

We describe in the context of the particle physics (PP) standard model (SM) `PP-SM' the understanding of the primordial properties and composition of the Universe in the temperature range $130\GeV>T>20\keV$. The Universe evolution is…

High Energy Physics - Phenomenology · Physics 2025-10-09 Johann Rafelski , Jeremiah Birrell , Christopher Grayson , Andrew Steinmetz , Cheng Tao Yang

In a previous paper (Ref. [1]) the presence of dark energy in our universe was explained as the fingerprint of a comprehensive, much older and expanding multiverse with positive spatial curvature, whose space-time is spanned by this energy,…

General Relativity and Quantum Cosmology · Physics 2018-09-06 Rebhan Eckhard

We consider a cosmological model of the late universe constituted by standard cold dark matter plus a dark energy component with constant equation of state w and constant effective speed of sound. Neglecting fluctuations in the dark energy…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-04 O. F. Piattella , D. L. A. Martins , L. Casarini

By considering the logarithmic correction to the energy density, we study the behavior of Hubble parameter in the holographic dark energy model. We assume that the universe is dominated by interacting dark energy and matter and the…

General Physics · Physics 2011-05-09 H. Mohseni Sadjadi , Mubasher Jamil

One of the most important questions nowadays in physics concerns the nature of the so-called dark energy. It is also a consensus among cosmologists that such a question will not be answered on the basis only of observational data. However,…

Astrophysics · Physics 2008-11-26 Deepak Jain , J. S. Alcaniz , Abha Dev

We investigate the relic density n_\chi of non-relativistic long-lived or stable particles \chi in non-standard cosmological scenarios. We calculate the relic abundance starting from arbitrary initial temperatures of the radiation-dominated…

High Energy Physics - Phenomenology · Physics 2008-11-26 Manuel Drees , Hoernisa Iminniyaz , Mitsuru Kakizaki

The Evolutionary Map of the Universe (EMU) is an all-sky survey in radio-continuum which uses the Australian SKA Pathfinder (ASKAP). Using galaxy angular power spectrum and the integrated Sachs-Wolfe effect, we study the potential of EMU to…

Cosmology and Nongalactic Astrophysics · Physics 2019-02-19 José Luis Bernal , Alvise Raccanelli , Ely D. Kovetz , David Parkinson , Ray P. Norris , George Danforth , Courtney Schmitt

A specific class of flat Emergent Universe (EU) is considered and its viability is tested in view of the recent observations. Model parameters are constrained from Stern data for Hubble Parameter and Redshift ($H(z)$ vs. $z$) and from a…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-17 B. C. Paul , S. Ghose , P. Thakur

Cosmology is investigated within a new, scalar theory of gravitation, which is a preferred-frame bimetric theory with flat background metric. Before coming to cosmology, the motivation for an " ether theory " is exposed at length; the…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Mayeul Arminjon

In this work, we study the extended viscous dark energy models in the context of matter perturbations. To do this, we assume an alternative interpretation of the flat Friedmann-Lema\^itre-Robertson-Walker Universe, through the nonadditive…

Cosmology and Nongalactic Astrophysics · Physics 2021-05-13 W. J. C. da Silva , R. Silva

General relativity can be reconciled with quantum field theory without quantising the geometry only if the metric evolves stochastically. In this article, we explore the consequences of such a proposal at early cosmological times. We find…

General Relativity and Quantum Cosmology · Physics 2026-05-29 Jonathan Oppenheim , Emanuele Panella , Andrew Pontzen

21cm tomography opens a window to directly study astrophysics and fundamental physics of early epochs in our Universe's history, the Epoch of Reionisation (EoR) and Cosmic Dawn (CD). Summary statistics such as the power spectrum omit…

Cosmology and Nongalactic Astrophysics · Physics 2022-02-09 S. Neutsch , C. Heneka , M. Brüggen

We forecast the expected cosmological constraints from a combination of probes of both the universal expansion rate and matter perturbation growth, in the form of weak lensing tomography, galaxy tomography, supernovae, and the cosmic…

Cosmology and Nongalactic Astrophysics · Physics 2012-08-10 Shahab Joudaki , Manoj Kaplinghat

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

We examine a simple dark sector extension where the observed dark matter (DM) abundance arises from a freeze-in process through the decay of heavy vector-like quarks into a scalar dark matter candidate. The detection prospects of such DM…

High Energy Physics - Phenomenology · Physics 2025-09-23 Anupam Ghosh , Partha Konar , Sudipta Show

We investigate the dynamics of the generalized $\Lambda$CDM model, which the $\Lambda$ term is running with the cosmological time. The $\Lambda(t)$ term emerges from the covariant theory of the scalar field $\phi$ with the self-interacting…

Cosmology and Nongalactic Astrophysics · Physics 2017-09-29 Marek Szydlowski , Aleksander Stachowski

Early dark energy has emerged as one of the more promising approaches to address the Hubble tension - the statistically significant disparity between measurements of the Hubble constant made using data from different epochs in cosmic…

Cosmology and Nongalactic Astrophysics · Physics 2022-10-03 Mark Trodden

We present models of the extragalactic background light (EBL) based on several scenarios of galaxy formation and evolution. We have treated galaxy formation with the Press-Schecter approximation for both cold dark matter (CDM) and cold+hot…

Astrophysics · Physics 2008-02-03 Donn MacMinn , Joel R. Primack
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