Related papers: Dark Energy from $\alpha$-Attractors
Dark energy can be characterized by a canonical scalar field, known as quintessence. Quintessence allows for a dynamical equation of state $-1 \le \omega \le -\frac{1}{3}$. A previous study by Oikonomou and Chatzarakis have shown that a…
Although equivalent to general relativity, teleparallel gravity is conceptually speaking a completely different theory. In this theory, the gravitational field is described by torsion, not by curvature. By working in this context, a new…
We propose a simple model for dark energy useful for comparison with observations. It is based on the idea that dark energy and inflation should be caused by the same physical process. As motivation, we note that Linde's simple chaotic…
We consider a physically viable cosmological model that has a field dependent Gauss-Bonnet coupling in its effective action, in addition to a standard scalar field potential. The presence of such terms in the four dimensional effective…
We investigate the inflationary attractors in models of inflation inspired from general conformal transformation of general scalar-tensor theories to the Einstein frame. The coefficient of the conformal transformation in our study depends…
It is shown that dark energy can be obtained from the interplay of the Higgs boson and the inflaton. A key element is the realization that electroweak symmetry breaking can trigger a second phase of rolling of the inflaton, which, when…
We consider the Brans-Dicke theory motivated by the $f(R) = R + \alpha R^n - \beta R^{2-n}$ model to obtain a stable minimum of the Einstein frame scalar potential of the Brans-Dicke field. As a result we have obtained an inflationary…
This study reviews the advances made in inflationary theory, especially regarding the seeming disparity between inflation energy and dark energy, and their significance to cosmic evolution as a whole. I attempt to connect the two sources of…
In light of the cosmological observations, we investigate dark energy models from the Horndeski theory of gravity. In particular, we consider cosmological models with the derivative self-interaction of the scalar field and the derivative…
The reheating phase after inflation is one of the least observationally constrained epochs in the evolution of the Universe. The forthcoming gravitational wave observatories will enable us to constrain at least some of the non-standard…
Starobinsky has suggested an inflation model which is obtained from the vacuum Einstein's equations modified by the one-loop corrections due to quantized matter fields. Although the one-loop gravitational action is not known for a general…
In this work we study the cosmological attractor models of inflation in connection with certain scalar-tensor theories of gravity, e.g $f(R)$ gravity and Brans-Dicke theory. For some particular choices of the functional degrees of freedom…
Using the evolution history of the universe, one can make constraint on the parameter space of dynamic dark energy models. We discuss two different parameterized dark energy models. Our results further restrict the combined constraints…
After Planck 2013, a broad class of inflationary models called \alpha-attractors was developed which has universal observational predictions. For small values of the parameter \alpha, the models have good consistency with the recent CMB…
We study a particular version of the theory of cosmological $\alpha$-attractors with $\alpha=1/3$, in which both the dilaton (inflaton) field and the axion field are light during inflation. The kinetic terms in this theory originate from…
We derive an $\alpha=1/3$ - attractor potential of slow-roll inflation in the geometric set-up of three intersecting $D7$ branes under $T^6/Z_N$ type of $CY_3$-compactification within type IIB/F theory with some near-conifold regions. The…
The formation of structure in the Universe offers some of the most powerful evidence in favour of the existence of dark matter in the Universe. We summarize recent work by ourselves and our collaborators, using linear and quasi-linear…
We consider the oscillating dark energy with periodic equation of state in two equivalent formulations: ideal fluid or scalar-tensor theory. It is shown that such dark energy suggests the natural way for the unification of early-time…
The class of Chaplygin gas models regarded as a candidate of dark energy can be realized by a scalar field, which could drive the variation of the fine structure constant $\alpha$ during the cosmic time. This phenomenon has been observed…
We present a model with a complex and a real scalar fields and a potential whose symmetry is explicitly broken by Planck-scale physics. For exponentially small breaking, the model accounts for the period of inflation in the early universe…