Related papers: Natural Quintessence with Gauge Coupling Unificati…
A cosmological model with perfect fluid and self-interacting quintessence field is considered in the framework of the spatially flat Friedmann-Robertson-Walker (FRW) geometry. By assuming that all physical quantities depend on the volume…
In a recent paper \cite{Artymowski:2020zwy} we suggested the possibility that the present acceleration of the Universe is due to thermodynamical behavior of unparticles. The model is free of scalar fields, modified gravity, a Cosmological…
Recent observations suggest that a large fraction of the energy density of the universe has negative pressure. One explanation is vacuum energy density; another is quintessence in the form of a scalar field slowly evolving down a potential.…
The action for gravity and the standard model includes, as well as the positive energy fermion and boson fields, negative energy fields. The Hamiltonian for the action leads through a positive and negative energy symmetry of the vacuum to a…
The current cosmological bound on the invisible axion scale may be avoided in the class of theories in which the gauge coupling constant is determined through the expectation value of some scalar field (e.g. moduli in supergravity and…
It has been proposed recently the existence of a non-minimal coupling between a canonical scalar field (quintessence) and gravity in the framework of teleparallel gravity, motivated by similar constructions in the context of General…
We perform a combined perturbation and observational investigation of the scenario of non-minimal derivative coupling between a scalar field and curvature. First we extract the necessary condition that ensures the absence of instabilities,…
Some properties of the world are fixed by physics derived from mathematical symmetries, while others are selected from an ensemble of possibilities. Several successes and failures of ``anthropic'' reasoning in this context are reviewed in…
We review recent developments in our understanding of the dynamics of strongly-coupled chiral $SU(N)$ gauge theories in four dimensions, problems which are potentially important in our quest to go beyond the standard $SU(3)_{QCD} \times…
If a scalar field couples to the Ricci scalar with a large non-minimal coupling, the Standard Model coupling parameters can differ above and below an intermediate field range of the scalar due to the non-renormalizability. In this paper, we…
Gravitational merging (or clustering) of cosmic objects is regarded as a possible source of the extra-acceleration of the universe at large scale. The merging/clustering of cosmic objects introduces a correction term in the equation of…
A recently proposed Asymptotically Safe cosmology provides an elegant mechanism towards understanding the nature of dark energy and its associated cosmic coincidence problem. The underlying idea is that the accelerated expansion of the…
It has recently been proposed that gravity-localized compactifications can generate the required gauge hierarchy without the need for hierarchically large extra spacetime dimensions. In this paper, we show that gauge coupling unification…
We consider a flat Universe filled with a vacuum energy coupled to matter and radiation by respectively positive coupling functions $Q_m$ and $Q_r$. We require that these functions be such as Universe exits from inflation to go to a…
Rolling tachyon field models are among the candidates suggested as explanations for the recent acceleration of the Universe. In these models the field is expected to interact with gauge fields and lead to variations of the fine-structure…
The principles of General Relativity allow for a non-vanishing cosmological constant, which can possibly be interpreted at least partially in terms of quantum-fluctuations of matter fields. Depending on sign and magnitude it can cause…
Gravity can arise in a conventional non-Abelian gauge theory in which a specific phenomenon takes place. Suppose there is a condensation of polarized instantons and antiinstantons in the vacuum state. Then the excitations of the gauge field…
The unification of gauge couplings suggests that there is an underlying (supersymmetric) unification of the strong, electromagnetic and weak interactions. The prediction of the unification scale may be the first quantitative indication that…
Using a simple Asymptotically Strong N=1 Susy SU(2) Gauge theory coupled to a {\bf{5}}-plet Chiral superfield we demonstrate the plausibility of the `` truly minimal '' Asymptotically Strong Grand Unification scenario proposed by us…
We construct the general model with only parallel positive tension 3-branes on $M^4 \times R^1$ and $M^4 \times R^1/Z_2$. The cosmology constant is sectional constant along the fifth dimension. In this general scenario, the 5-dimensional…