Related papers: Quintessential Haloes around Galaxies
We consider an alternative cold dark matter candidate, ultralight bosons ($m>10^{-22}$eV) described by a complex scalar field (SFDM) with global U(1) symmetry, with comoving particle number density conserved after particle production during…
What is the nature - continuous or discrete - of matter and of its fundamental interactions? The physical meaning, the properties and the consequences of a discrete scalar field are discussed; limits for the validity of a mathematical…
We consider the Abelian model of a complex scalar field coupled to a gauge field within the framework of General Relativity and search for cosmological solutions. For this purpose we assume a homogeneous, isotropic and uncharged Universe…
Dark matter in the universe seems to be one of the most important puzzles science has to face in this moment. In this essay we point out that dark matter could be a spin-0 fundamental interaction of Nature rather than a simple particle.…
We propose experimental schemes for detection an axionic condensate supposed to be cosmic dark matter. Various procedures are considered in dependence on the value of the axion mass. There are well known indications that a large part of the…
We discuss some of the issues which we encounter when we try to invoke the scalar-tensor theories of gravitation as a theoretical basis of quintessence. One of the advantages of appealing to these theories is that they allow us to implement…
Diverse cosmological and astrophysical observations strongly hint at the presence of dark matter and dark energy in the Universe. One of the main goals of Cosmology is to explain the nature of these two components. It may well be that both…
Cosmology with a three-form field interacting with cold dark matter is considered. In particular, the mass of the dark matter particles is assumed to depend upon the amplitude of the three-form field invariant. In comparison to coupled…
Observed rotational curves of neutral hydrogen clouds strongly support the fact that galactic halo contains huge amount of nonluminous matter, the so called gravitational dark matter. The nature of dark matter is a point of debate among the…
We study a spherically symmetric fluctuation of scalar dark matter in the cosmos and show that it could be the dark matter in galaxies, provided that the scalar field has an exponential potential whose overall sign is negative and whose…
We investigate whether there are any cosmological evidences for a scalar field with a mass and coupling to matter which change accordingly to the properties of the astrophysical system it "lives in", without directly focusing on the…
Many problems of cold dark matter models such as the cusp problem and the missing satellite problem can be alleviated, if galactic halo dark matter particles are ultra-light scalar particles and in Bose-Einstein condensate (BEC), thanks to…
In this paper, we propose a new approach to study the dark sector of the universe by considering the dark energy as emerging a q-deformed bosonic scalar field which is not only interacting with the dark matter, but also non-minimally…
Chameleon fields are scalar fields whose mass depends on the ambient matter density. We investigate the effects of these fields on the growth of density perturbations on sub-galactic scales and the formation of the first dark matter halos.…
Collisionless particles, such as cold dark matter, interact only by gravity and do not have any associated length scale, therefore the dark halos of galaxies should have negligible core radii. This expectation has been supported by…
We review the work done so far aimed at modeling in an alternative way the dark matter in the Universe: the scalar field/ Bose-Einstein condensate dark matter (SFDM/BEC) model. We discuss a number of important achievements and…
Dark energy models and modified gravity theories have been actively studied and the behaviors in the solar system have been also carefully investigated in a part of the models. However, the isotropic solutions of the field equations in the…
The observed accelerating universe indicates the presence of Dark Energy which is probably interpreted in terms of an extremely light gravitational scalar field. We suggest a way to probe this scalar field which contributes to optical…
We propose a new class of quintessence models in which late times oscillations of a scalar field give rise to an effective equation of state which can be negative and hence drive the observed acceleration of the universe. Our ansatz…
The main aim of this work is to explore the possibility that cold dark matter (CDM) and early dark energy (EDE) can be described by canonical scalar fields that are coupled at the level of its conservation equations. The formalism covers…