Related papers: Hierarchy problem in the shell-Universe model
I critically discuss in a pedagogical and phenomenological way a few crucial tests challenging the claims by Pietronero and collaborators that there is no evidence from available galaxy catalogues that the Universe is actually homogeneous…
From a broader perspective, the heliosphere and planetary magnetospheres provide a test bed to explore the plasma physics of the Universe. In particular, the underlying nonlinear coupling of different spatial and temporal scales plays a key…
Halo models of the large scale structure of the Universe are critically examined, focusing on the definition of halos as smooth distributions of cold dark matter. This definition is essentially based on the results of cosmological N-body…
The Cyclic Model is a radical, new cosmological scenario which proposes that the Universe undergoes an endless sequence of epochs which begin with a `big bang' and end in a `big crunch.' When the Universe bounces from contraction to…
Anthropic solutions to the cosmological constant problem require seemingly unnatural scalar field potentials with a very small slope or domain walls (branes) with a very small coupling to a four-form field. Here we introduce a class of…
The Cosmological Principle states that the universe is both homogeneous and isotropic. This, alone, is not enough to specify the global geometry of the spacetime. If we were able to measure both the Hubble constant and the energy density we…
We explore a cyclic universe due to phantom and quintessence fields. We find that, in every cycle of the evolution of the universe, the phantom dominates the cosmic early history and quintessence dominates the cosmic far future. In this…
A generalized quintessence model is presented which corresponds to a richer vacuum structure that, besides a time-dependent, slowly varying scalar field, contains a varying cosmological term. From first principles we determine a number of…
We discuss the way of solving the hierarchy problem. We show that starting at the Planck scale, the three energy scales -- inflationary, electroweak and the cosmological ones can be restored. The formation of small parameters is proposed…
We generalize solutions of Einstein's equations for intersecting branes in higher dimensional spacetimes to the nonstatic case, modeling an expanding universe. The relation between the Hubble rate, the brane tensions, and the bulk…
The Universe could be spatially flat, positively curved or negatively curved. Each option has been popular at various times, partly affected by an understanding that models tend to evolve away from flatness. The curvature of the Universe is…
After a short history of the $\Lambda$-term it is explained why the (effective) cosmological constant is expected to obtain contributions from short-distance physics, corresponding to an energy at least as large as the Fermi scale. The…
The matter content of the Universe is generally regarded as a perfect fluid on sufficiently large scales, for all epochs. But the recent cosmological matter distribution, consisting of an (ideally) random distribution of gravitationally…
We study some aspects of cosmology in a five-dimensional model with matter, radiation and cosmological constant on the four-dimensional brane(s) and without matter in the bulk. The action of the model does not contain explicit curvature…
Particles have tremendous potential as astronomical messengers, and conversely, studying the universe as a whole also teaches us about particle physics. This thesis encompasses both of these research directions. Many models predict a…
Standard quantum field theory arguments predict an enormous cosmological constant. But what would this mean observationally? For a homogeneous universe the answer is clear, but if the universe is inhomogeneous at the Planck scale, the…
In the standard model in universal extra dimensions (UED) the mass of the Higgs field is driven to the cutoff of the higher-dimensional theory. This re-introduces a small hierarchy since the compactification scale 1/R should not be smaller…
Invariablly justified representations of the Wave Universe Concept-WU Concept (see monography-Chechelnitsky A.M. Extremum, Stability and Resonance in Astrodynamics..., etc. and other publications) indicate a principle incorrectness of…
Cosmology is undergoing an explosive period of activity, fueled both by new, accurate astrophysical data and by innovative theoretical developments. Cosmological parameters such as the total density of the Universe and the rate of…
The source of the acceleration of the expansion of the Universe is still unknown. We examine some consequences of the possible scale invariance of the empty space at large scales. The central hypothesis of this work is that, at macroscopic…