Related papers: Fluid Dark Matter
The galactic `dark matter' effect is regarded as one of the major problems in fundamental physics. Here it is explained as a self-interaction dynamical effect of space itself, and so is not caused by an unknown form of matter. Because it…
Dark matter constitutes $26\%$ of the total energy in our universe, but its nature remains elusive. Among the assortment of viable dark matter candidates, particles and fields with masses lighter than $40 \mathrm{eV}$, called ultralight…
Dark matter, one of the fundamental components of the universe, has remained mysterious in modern cosmology and particle physics, and hence, this field is of utmost importance at present moment. One of the foundational questions in this…
In this work we investigate the evolution of a Universe consisted of a scalar field, a dark matter field and non-interacting baryonic matter and radiation. The scalar field, which plays the role of dark energy, is non-minimally coupled to…
A cosmological model with pressurelless matter and a fluid of negative pressure is studied. At perturbative level, fluctuations of both fluids are considered. It is shown that at least at very large scales, the fluid of negative pressure,…
Treating dark matter at large scales as an effectively viscous fluid provides an improved framework for the calculation of the density and velocity power spectra compared to the standard assumption of an ideal pressureless fluid. We discuss…
In earlier work it was pointed out that for warped product spacetimes the conformal (geometrical moduli) excitations of the internal compactified factor spaces should be observable as massive scalar fields in the external spacetime. Here we…
If there exist fields of mass of the order of $10^{13}$ GeV and large field inflation occurs, their interaction with classical gravitation will generate enough particles to give the universe critical density today regardless of their…
We consider minimal extensions of the recently proposed Mimetic Dark Matter and show that by introducing a potential for the mimetic non-dynamical scalar field we can mimic nearly any gravitational properties of the normal matter. In…
Axions are produced during a period of dilaton-driven inflation by amplification of quantum fluctuations. We show that for some range of string cosmology parameters and some range of axion masses, primordial axions may constitute a large…
Motivated by the projectable Horava--Lifshitz model/mimetic matter scenario, we consider a particular modification of standard gravity, which manifests as an imperfect low pressure fluid. While practically indistinguishable from a…
Inflation driven by a single dark spinor field is discussed. We define the notion of a dark spinor field and derive the cosmological field equations for such a matter source. The conditions for inflation are determined and an exactly…
We propose a dark energy model with a logarithmic cosmological fluid which can result in a very small current value of the dark energy density and avoid the coincidence problem without much fine-tuning. We construct a couple of dynamical…
In the general frameworks of an earlier introduced quartet-metric/multi-component gravity, a theory of a massive scalar graviton supplementing the massless tensor one is consistently deduced. The peculiarities of the scalar-graviton field…
Owing to the renewed interest in dark matter after the upgrade of the large hadron collider and its dedication to dark matter research it is timely to reassess the whole problem. Considering dark matter is one way to reconcile the…
We study static configurations of dark matter coupled to a scalar field responsible for the dark energy of the Universe. The dark matter is modelled as a Fermi gas within the Thomas-Fermi approximation. The mass of the dark matter particles…
We propose a unified single-field description of the galactic Dark Matter and various uniform scalar fields for the inflation and cosmological constant. The two types of effects could originate from a fluid of both spatially and temporally…
Recently, it was proposed that a small true vacuum universe can inflate spontaneously, in principle. Furthermore, there should be matter creation in vacuum inflation due to quantum fluctuations, and the matter created will influence the…
Galactic dark matter is modelled by a scalar field. In particular, it is shown that an analytically solvable toy model with a non-linear self-interaction potential U(Phi) leads to dark halo models which have the form of quasi-isothermal…
One of the simplest possible candidates for dark matter is a stable scalar singlet beyond the Standard Model. If its mass is below the Hubble scale during inflation, long-wavelength modes of this scalar will be excited during inflation, and…