Related papers: Changing universe model with applications
Recently the Chiral Cosmological Model (CCM) coupled to cold dark matter (CDM) has been investigated as $\sigma$CDM model to study the observed accelerated expansion of the Universe. Dark sector fields (as Dark Energy content) coupled to…
Over the last decades, cosmological simulations of galaxy formation have been instrumental for advancing our understanding of structure and galaxy formation in the Universe. These simulations follow the non-linear evolution of galaxies…
Recent observations of the Universe have led to a conclusion suppressing an up-to-now supposed deceleration of the Universe caused by attractive gravitational forces. Contrary, there is a renaissance of the cosmological member lambda and…
Over the past three years we have determined the basic features of the Universe -- spatially flat; accelerating; comprised of 1/3 a new form of matter, 2/3 a new form of energy, with some ordinary matter and a dash of massive neutrinos; and…
We show that a cosmology driven by gravitationally induced particle production of all non-relativistic species existing in the present Universe mimics exactly the observed flat accelerating $\Lambda$CDM cosmology with just one dynamical…
In the present article we have investigated a very natural question regarding the dynamics of the universe, namely, the possibility of its decelerating phase immediately after the present accelerating phase. To begin with, we have focused…
The traditional "explanation" for the observed acceleration of the universe is the existence of a positive cosmological constant. However, this can hardly be a truly convincing explanation, as an expanding universe is not expected to have a…
Creation of Cold Dark Matter (CCDM), in the context of Einstein Field Equations, leads to a negative creation pressure, which can be used to explain the accelerated expansion of the Universe. Recently, it has been shown that the dynamics of…
Present-day extragalactic observations are mostly rather well-modelled by a general-relativistic model, the $\Lambda$ CDM model. The model appears to surpass the limits of known physics by requiring that the Universe be dominated by "dark…
We carry out an analysis of the cosmological perturbations in general relativity for three different models which are good candidates to describe the current acceleration of the Universe. These three set-ups are described classically by…
The abundance of the most massive objects in the Universe at different epochs is a very sensitive probe of the cosmic background evolution and of the growth history of density perturbations, and could provide a powerful tool to distinguish…
Modified Dark Matter (MDM) is a phenomenological model of dark matter, inspired by gravitational thermodynamics, that naturally accounts for the universal acceleration constant observed in galactic rotation curve data; a critical…
In cosmology based on general relativity, the universe is modeled as a fluid. The transition from the Einstein field equation to its large-scale (cosmological) version is thus analogous to the transition, for a system consisting of a large…
The Standard Model of cosmology, $\Lambda$CDM, while enormously successful, is currently unable to account for several cosmological anomalies the most prominent of which are in the measurements of the Hubble parameter and $S_8$.…
The success of the Lambda-CDM model on large scales does not extend down to galaxy scales. We list a dozen problems of the dark matter hypothesis, some of which arise in specific models for the formation of structure in the universe, while…
In the Emergent scenario, the Universe should evolve from a non-singular state replacing the typical singularity of General Relativity, for any initial condition. For the scalar field model in [1] we show that only a set of measure zero of…
Perhaps the deepest mystery of our accelerating Universe in expansion is the existence of a tiny and rigid cosmological constant, $\Lambda$. Its size is many orders of magnitude below the expected one in the standard model of particle…
New systematic classification of cosmological models of the present Universe is introduced. After making the comparison of these models with all existing observational data three viable models remain: the cold dark matter model with the…
Interactions inside the cosmological dark sector influence the cosmological dynamics. As a consequence, the future evolution of the Universe may be different from that predicted by the $\Lambda$CDM model. We review main features of several…
Assuming that observers located inside the Universe measure a time flow which is different from the time appearing in the Friedmann-Lemaitre equation, and determining this time flow such that the Universe always appears flat to these…