Related papers: Imperfect dark matter with higher derivatives
Recently modified gravitational theories which mimic the behaviour of dark matter, the so-called "Mimetic Dark Matter", have been proposed. We study the consistency of such theories with respect to the absence of ghost instability and…
Previous studies have examined the holographic principle as a means of producing dark energy. Here we propose instead the possibility of holographic dark matter. In this case, dark matter does not arise in the framework of particle physics…
In this study one resorts to the phenomenology of models endowed with a non-minimal coupling between matter and geometry, in order to develop a mechanism through which dynamics similar to that due to the presence of dark matter is…
We outline a dynamical dark energy scenario whose signatures may be simultaneously tested by astronomical observations and laboratory experiments. The dark energy is a field with slightly sub-gravitational couplings to matter, a logarithmic…
Under the existence of a massless spinor with respect to the total connection in a spacetime modeled as a Lorentzian manifold with internal boundaries, such as finite volume semi-classical Black Holes, we show that a topological mechanism…
We propose that dark matter is composed of particles that naturally have the correct thermal relic density, but have neither weak-scale masses nor weak interactions. These WIMPless models emerge naturally from gauge-mediated supersymmetry…
We introduce a new paradigm for dark matter (DM) interactions in which the interaction strength is asymptotically safe. In models of this type, the coupling strength is small at low energies but increases at higher energies, and…
We introduce a new proposal for the onset of cosmic acceleration based on mass-varying neutrinos. When massive neutrinos become nonrelativistic, the $Z_2$ symmetry breaks, and the quintessence potential becomes positive from its initially…
A set of temporal singularities (transients) in the mass-energy density and pressure, bearing a specific mathematical structure which represents a new solution to the continuity equation (\ie~conservation of mass-energy) and satisfying the…
We push ahead the idea developed in [24], that some fraction of the dark matter and the dark energy can be explained as a relativistic effect. The inhomogeneity matter generates gravitational distortions, which are general relativistically…
There are compelling reasons to believe that the dark matter of the universe is constituted, in large part, by non-baryonic collisionless particles with very small primordial velocity dispersion. Such particles are called cold dark matter…
Inelastic dark matter (IDM) models feature an energy threshold for scattering with Standard Model particles, which enables their consistency with the increasingly stringent limits placed by direct detection experiments. In a typical…
The observed excess of gravitational forces in galaxies and galactic clusters is usually referred as the existence of "dark matter particles" of unknown origin. An alternative explanation of the dark matter effect is presented here by…
We entertain the possibility that the phenomena typically attributed to dark matter may have a fundamentally emergent nature, rather than arising from new particle degrees of freedom. To illustrate this idea, we consider a field-theoretic…
The Special Relativity allows the possibility of a class of particles, known tachyons, that have spacelike 4-velocities, i.e., which move with velocity greater than speed of light in vacuum. In this existence frame, the tachyons have energy…
We review and develop a new class of "dark energy" models, in which the relativistic theory of solids is used to construct material models of dark energy. These are models which include the effects of a continuous medium with well defined…
A non-equilibrium thermodynamic analysis has been done for the interacting dark fluid in the universe bounded by the event horizon.From observational evidences it is assumed that at present the matter in the universe is dominated by two…
The standard paradigm of collisionless cold dark matter is in tension with measurements on large scales. In particular, the best fit values of the Hubble rate $H_0$ and the matter density perturbation $\sigma_8$ inferred from the cosmic…
We perform numerical evolutions of cosmological scenarios using a standard general relativistic code in spherical symmetry. We concentrate on two different situations: initial matter distributions that are homogeneous and isotropic, and…
This paper explores the possibility that dark matter particles are objects with a set of excitable levels, as for a string or drum. A change in excitation is associated with the absorption or emission of a photon, and the probability of…