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The hypothesis of existence of primordial black holes with large masses (\geq 10^6 M\odot), formed at the earliest stages of the Universe evolution, is considered in the paper. The possibility does not contradict some theories, see e.g.…

Cosmology and Nongalactic Astrophysics · Physics 2013-09-17 V. K. Dubrovich , S. I. Glazyrin

We address the emerging discrepancy between the Big Bang Nucleosynthesis data and standard cosmology, which asks for a bit longer evolution time. If this effect is real, one possible implication (in a framework of brane cosmology model) is…

High Energy Physics - Theory · Physics 2009-08-18 V. V. Flambaum , E. V. Shuryak

One hundred years ago we did not know how stars generate energy, the age of the Universe was thought to be only millions of years, and our Milky Way galaxy was the only galaxy known. Today, we know that we live in an evolving and expanding…

Astrophysics · Physics 2008-11-26 Michael S. Turner , J. Anthony Tyson

We investigate nucleosynthesis and element formation in the early universe in the framework of higher dimensional cosmology. For this purpose we utilize a previous solution of the present author, which may be termed as the generalized…

General Relativity and Quantum Cosmology · Physics 2015-05-14 S. Chatterjee

The initial cosmological singularity in the framework of the general theory of relativity is resolved by introducing the effect of the uncertainty principle of quantum theory without violating conventional laws of physics. A plausible…

Astrophysics · Physics 2009-11-07 D. C. Choudhury

A new varying-$c$ cosmological model constructed using two additional assumptions, which was introduced in our previous work, is briefly reviewed and the dynamic equation of the model is derived distinctly from a semi-Newtonian approach.…

General Relativity and Quantum Cosmology · Physics 2010-09-28 Hossein Shojaie , Mehrdad Farhoudi

We investigate whether Big Bang nucleosynthesis (BBN) remains compatible with the Covarying Coupling Constants plus Tired Light (CCC+TL) cosmology. In this framework, only quantities with explicit length dimensionality covary through a…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-27 Rajendra P. Gupta , Nikolaos Samaras

The standard model of cosmology assumes that our Universe began 14 Gyrs (billion years) ago from a singular Big Bang creation. This can explain a vast range of different astrophysical data from a handful of free cosmological parameters.…

Cosmology and Nongalactic Astrophysics · Physics 2022-04-26 Enrique Gaztanaga

We investigate the effects that arise from the inclusion of Weylian boundary terms in the Einstein gravitational field equations in the Big Bang Nucleosynthesis (BBN) framework. With the help of the generalized Friedmann equations for a…

General Relativity and Quantum Cosmology · Physics 2026-04-28 Teodora M. Matei , Cristian Croitoru , Tiberiu Harko

Recent measurement of the primordial $^4$He abundance $Y_p$ from EMPRESS suggests a cosmological scenario with the effective number of neutrino species deviated from the standard value and non-zero lepton asymmetry. We argue that the…

Cosmology and Nongalactic Astrophysics · Physics 2023-05-31 Tomo Takahashi , Sora Yamashita

A new evaluation of the constraint on the number of light neutrino species (N_nu) from big bang nucleosynthesis suggests a discrepancy between the predicted light element abundances and those inferred from observations, unless the inferred…

High Energy Physics - Phenomenology · Physics 2009-04-13 N. Hata , R. J. Scherrer , G. Steigman , D. Thomas , T. P. Walker , S. Bludman , P. Langacker

The fundamental paradox of the incompatibility of the observed large-scale uniformity of the Universe with the fact that the age of the Universe is finite is overcome by the introduction of an initial a period of superluminal expansion of…

High Energy Physics - Phenomenology · Physics 2010-11-02 Konstantinos Dimopoulos

A model for gravitational collapse where the event horizon is a quantum critical phase transition is extended to provide an explanation for the origin of the observable universe, where the expanding universe that we observe today was…

General Relativity and Quantum Cosmology · Physics 2016-02-09 George Chapline , James Barbieri

In the standard model of cosmology, the Universe began its expansion with an anomalously low entropy, which then grew dramatically to much larger values consistent with the physical conditions at decoupling, roughly 380,000 years after the…

Cosmology and Nongalactic Astrophysics · Physics 2021-03-22 Fulvio Melia

The origins of matter and radiation in the universe lie in a Hot Big Bang. We present a number of well-motivated cosmologies in which the Big Bang occurs through a strong first order phase transition -- either at the end of inflation, after…

Cosmology and Nongalactic Astrophysics · Physics 2022-11-30 Katherine Freese , Martin Wolfgang Winkler

We perform calculations of dark photon production and decay in the early universe for ranges of dark photon masses and vacuum coupling with standard model photons. Simultaneously and self-consistently with dark photon production and decay,…

Cosmology and Nongalactic Astrophysics · Physics 2021-01-05 Jung-Tsung Li , George M. Fuller , Evan Grohs

We show how recent data from observations of the cosmic microwave background may suggest the presence of additional radiation density which appeared after big bang nucleosynthesis. We propose a general scheme by which this radiation could…

Cosmology and Nongalactic Astrophysics · Physics 2011-05-10 Willy Fischler , Joel Meyers

The recently observed Deuterium abundance in a low- metallicity high-redshift hydrogen cloud, which is about ten times larger than that observed in the near interstellar medium, is that expected from the Standard Big Bang Nucleosynthesis…

Astrophysics · Physics 2009-10-28 Arnon Dar

The big bang hypothesis is widely accepted despite numerous physics conflicts. It rests upon two experimental supports, galactic red shift and the cosmic microwave background. Both are produced by dark matter, shown here to be hydrogen…

General Physics · Physics 2008-03-31 Robert K. Soberman , Maurice Dubin

In this work we consider quantum electromagnetic fields in an expanding universe. We start by reviewing the difficulties found when trying to impose the Lorenz condition in a time-dependent geometry. Motivated by this fact, we explore the…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-17 Jose Beltran Jimenez , Antonio L. Maroto