Related papers: Cosmological scalar fields and Big-Bang nucleosynt…
We consider a dynamics of Higgs' field in the framework of cosmological models involving the scalar field from Nonsymmetric Kaluza-Klein (Jordan-Thiry) Theory. The field plays here a role of a quintessence field. We consider phase…
The cosmological evolution of a quintessence-like scalar field, phi, coupled to matter and gauge fields leads to effective modifications of the coupling constants and particle masses over time. We analyze a class of models where the scalar…
The scalar field plays an fundamental role in the investigation of confinement property characterising many particle physics models. This is achieved by coupling this particle directly with gauge fields at the lagrangian level. We have…
The two most popular candidates for dark energy, i.e. a cosmological constant and quintessence, are very difficult to distinguish observationally, mostly because the quintessence field does not have sizable fluctuations. We study a scalar…
I describe a new class of quintessence+CDM models in which late time scalar field oscillations can give rise to both quintessence and cold dark matter. Additionally, a versatile ansatz for the luminosity distance is used to reconstruct the…
We study the large-scale structure formation in the Universe in the frame of scalar-tensor theories as an alternative to general relativity. We review briefly the Newtonian limit of non-minimally coupled scalar-tensor theories and the…
In this work we investigate the effect of a kind of scalar field, called chameleon, on the evolution of universe. We put this scalar field in the bulk. It is displayed that this scalar field gives us an exponential expansion in early time…
In this paper we consider $\phi^2$ scalar field potential as a candidate to dark matter. If it is an ultralight boson particle, it condensates like a Bose-Einstein system at very early times and forms the basic structure of the Universe.…
We propose a mechanism for the generation of magnetic fields on cosmological scales that is operative after recombination. An essential ingredient is an instability (of parametric resonance type) of the electromagnetic field driven by an…
The dependence of the parameters of the evolution of scalarly charged Black Holes (BHs) in the early Universe on the parameters of field-theoretic theories of interaction, the influence of the geometric factor of the structure of the…
We study effect of superhorizon tensor perturbations on scalar perturbations, so called effect of clustering fossils, in cosmological model in which inflation is driven by both solid matter and scalar field. The effect deforms primordial…
The study of the Universe on ultra-large scales is one of the major science cases for the Square Kilometre Array (SKA). The SKA will be able to probe a vast volume of the cosmos, thus representing a unique instrument, amongst…
Recently it has been proposed that the main contributor to the dark energy of the Universe is a dynamical, slow evolving, spatially inhomogeneous scalar field called quintessence. We investigate the behavior of this scalar field at galactic…
The discovery of the accelerating universe indicates strongly the presence of a scalar field which is not only expected to solve today's version of the cosmological constant problem, or the fine-tuning and the coincidence problems, but also…
In the present work, an attempt has been made to explain the recent cosmic acceleration with two mutually interacting scalar fields, one being the Brans-Dicke scalar field and the other a quintessence scalar field. Conditions have been…
From higher dimensional theories, e.g. string theory, one expects the presence of non-minimally coupled scalar fields. We review the notion of conformal frames in cosmology and emphasize their physical equivalence, which holds at least at a…
In this paper, we investigate cosmological particle production using quantum field theory (QFT). We will consider how production of scalar particles can occur in an expanding universe. By introducing a time-dependent energy parameter…
Stable scalars can be copiously produced in the Early Universe even if they have no coupling to other fields. We study production of such scalars during and after (high scale) inflation, and obtain strong constraints on their mass scale.…
Specific action for isotropic fluctuations of scalar field is derived under the condition of 4D cut-off. It is implemented into the estimates of dark energy scale consistent with current cosmological data.
Despite the widespread presence of magnetic fields, their origin, evolution and role are still not well understood. Primordial magnetism sounds appealing but is not problem free. The magnetic implications for the large-scale structure of…