Related papers: Theoretical basis for a solution to the cosmologic…
It is suggested that the true ground state of the world has exactly vanishing vacuum energy and that the cosmological constant that seems to have been observed is due to our region of the universe being stuck in a false vacuum, whose energy…
One of the most fundamental questions in cosmology is if dark energy is related just to a constant or it is something more complex. In this work, we call the attention to the fact that, under very general conditions, dark energy can be…
Increasing improvements in the independent determinations of the Hubble constant and the age of the universe now seem to indicate that we need a small non-vanishing cosmological constant to make the two independent observations consistent…
Quantum field theory predicts that vacuum energy (or what is the same, cosmological constant) should be 50-100 orders of magnitude larger than the existing astronomical limit. A very brief review of possible solutions of this problem is…
The physical nature of the presently dominating enigmatic dark energy in the expanding universe is demonstrated to be explainable as an excess of the kinetic energy with respect to its potential energy. According to traditional Friedman…
Motivated by results implying that the constituents of dark matter (DM) might be collisional, we consider a cosmological (toy-) model, in which the DM itself possesses some sort of thermodynamic properties. In this case, not only can the…
In this paper, it is shown that the cosmological model that was introduced in a sequence of three earlier papers under the title, A Dust Universe Solution to the Dark Energy Problem, can be used to resolve the problem of the great mismatch…
The standard cosmological model is based on general relativity and includes dark matter and dark energy. An important prediction of this model is a fixed relationship between the gravitational potentials responsible for gravitational…
Cold Dark Matter (CDM) has become the standard modern theory of cosmological structure formation. Its predictions appear to be in good agreement with data on large scales, and it naturally accounts for many properties of galaxies. But…
An alternative cosmological model is presented, which avoids the requirement of dark energy and dark matter. Based on the proposition that energy conservation should be valid not only locally but also globally, the energy tensor of general…
We suggest a new perspective on the Cosmological Constant Problem by scrutinizing its standard formulation. In classical and quantum mechanics without gravity, there is no definition of the zero point of energy. Furthermore, the Casimir…
Theoretical results on a conventional approach to the dark energy (DE) concept are reviewed and discussed. According to them, there is absolutely no need for a novel DE component in the Universe, provided that the associated matter-energy…
Combining general relativity and gravitational gauge theory, the cosmological constant is determined theoretically. The cosmological constant is related to the average vacuum energy of gravitational gauge field. Because the vacuum energy of…
Among the suggested solutions to the cosmological constant problem, we find the idea of a dynamic vacuum, with an energy density decaying with the universe expansion. We investigate the possibility of a variation in the gravitational…
In this review, I discuss briefly how the presence of a cosmological constant in the Universe may imply a decoherent evolution of quantum matter in it, and as a consequence a fundamental irreversibility of time unrelated in principle to CP…
It was recently suggested that the cosmological constant problem as viewed in a non-perturbative framework is intimately connected to the choice of time and a physical Hamiltonian. We develop this idea further by calculating the…
A cosmological constant fits all current dark energy data, but requires two extreme fine tunings, both of which are currently explained by anthropic arguments. Here we discuss anti-anthropic solutions to one of these problems: the cosmic…
This thesis deals with the averaging problem in cosmology, which has gained considerable interest in recent years, and is concerned with correction terms (after averaging inhomogeneities) that appear in the Einstein equations when working…
We explore the effects of a positive cosmological constant on astrophysical and cosmological configurations described by a polytropic equation of state. We derive the conditions for equilibrium and stability of such configurations and…
We show that the presence of a temporal electromagnetic field on cosmological scales generates an effective cosmological constant which can account for the accelerated expansion of the universe. Primordial electromagnetic quantum…