Related papers: Big Bang nucleosynthesis and physics beyond the St…
This essay is a nontechnical primer for a broader audience, in which I paint a broad-brush picture of modern cosmology. I begin by reviewing the evidence for the big bang, including the expansion of our Universe, the cosmic microwave…
Current observational data favor cosmological models which differ from the standard model due to the presence of some form of dark energy and, perhaps, by additional contributions to the more familiar dark matter. Primordial nucleosynthesis…
I propose a unified model of particle physic and cosmology based on both a new extension of the standard particle model and the fundamental principle of the standard cosmology. Beyond the SM, I introduce several species of dark fields with…
In the framework of the standard, hot big bang cosmological model the dynamics of the early evolution of the universe is controlled by the energy density of relativistic particles, among which neutrinos play an important role. In…
Although big bang cosmology effectively models even the most puzzling observational data, it offers no insight into why the cosmological expansion should occur at all. In this paper it is suggested that a finite Universe poses particular…
We investigate the sensitivity of a universe's nuclear entropy after Big Bang nucleosynthesis (BBN) to variations in both the baryon-to-photon ratio and the temporal evolution of cosmological expansion. Specifically, we construct…
Big Bang Nucleosynthesis (BBN) is the synthesis of the light nuclei, Deuterium, He3, He4 and Li7, during the first few minutes of the universe. This review concentrates on recent improvements in the measurement of the primordial (after BBN,…
The Standard Cosmological Model has experienced tremendous success at reproducing observational data by assuming a universe dominated by a cosmological constant and dark matter in a flat geometry. However, several studies, based on local…
In this review, we first reassess the supernova remnant paradigm for the origin of galactic cosmic rays in the light of recent cosmic-ray data acquired by the Voyager 1 spacecraft. We then describe the theory of light element…
Using thermodynamics-gravity conjecture, we present the formal derivation of the modified Friedmann equations inspired by the Barrow entropy, $S\sim A ^{1+\delta/2}$, where $0\leq\delta\leq 1$ is the Barrow exponent and $A$ is the horizon…
We consider the implications of the modified dispersion relations, due to the noncommutativity of the spacetime, for a photon gas filling the early Universe in the framework of the Big Bang Nucleosynthesis (BBN) processes, during the period…
We develop a string-inspired model for particle cosmology, based on a flipped SU(5)$\times$U(1) gauge group formulated in a no-scale supergravity framework. The model realizes Starobinsky-like inflation, which we assume to be followed by…
We have recently considered cosmologies in which the Universal scale factor varies as a power of the age of the Universe and concluded that they cannot satisfy the observational constraints on the present age, the magnitude-redshift…
Big Bang Nucleosynthesis (BBN) and the Cosmic Background Radiation (CBR) provide complementary probes of the early evolution of the Universe and of its particle content. Neutrinos play important roles in both cases, influencing the…
The conventional Big Bang model successfully anticipates the initial abundances of 2H(D), 3He, and 4He, aligning remarkably well with observational data. However, a persistent challenge arises in the case of 7Li, where the predicted…
We describe how cosmology has converged towards a beautiful model of the Universe: the Big Bang Universe. We praise this model, but show there is a dark side to it. This dark side is usually called ``the cosmological problems'': a set of…
We constrain proposed phenomenological models for a vacuum energy which decays with the expansion of the universe from considerations of standard big bang nucleosynthesis. Several such models which attempt to solve the cosmological age…
We propose a cosmological scenario in which the hot big bang universe is produced by the collision of a brane in the bulk space with a bounding orbifold plane, beginning from an otherwise cold, vacuous, static universe. The model addresses…
The early universe according to the big bang and the grand unified theories is discussed. The shortcomings of big bang are summarized together with their resolution by inflationary cosmology. Inflation, the subsequent oscillation and decay…
We propose a model of the Universe based on Minkowski flat space-time metric. In this model the space-time does not evolve. Instead the matter evolves such that all the mass parameters increase with time. We construct a model based on…