Related papers: Connecting inflation with late cosmic acceleration…
A rapid phase of accelerated expansion in the early universe, known as inflation, dilutes all matter except the vacuum induced quantum fluctuations. These are responsible for seeding the initial perturbations in the baryonic matter, the…
Cosmic inflation may exhibit stochastic periods during which quantum fluctuations dominate over the semi-classical evolution. Extracting observables in these regimes is a notoriously difficult program as quantum randomness makes them fully…
Current astronomical observations are successfully explained by the present cosmological paradigm based on the concordance model ($\Lambda_0$CDM + Inflation). However, such a scenario is composed of a heterogeneous mix of ingredients for…
Our primary objective is the formulation of a plausible cosmological inflationary model entirely in terms of a pure modified gravity without any a priori matter couplings within the formalism of non-Riemannian spacetime volume elements. The…
The union of high-energy particle theories and gravitation often gives rise to an evolving strength of gravity. The standard picture of the earliest universe would certainly deserve revision if the Planck mass, which defines the strength of…
We investigate the initiation of cosmic inflation, in full numerical relativity, from pre-inflationary scenarios with large tensor and vector fluctuations in the metric. These settings are characterized by having large values in the Weyl…
The big bang model and the history of the early universe according to the grand unified theories are introduced. The shortcomings of big bang are discussed together with their resolution by inflationary cosmology. Inflation, the subsequent…
We show that cosmic acceleration can arise due to very tiny corrections to the usual gravitational action of General Relativity of the form $R^n$, with $n<0$. This eliminates the need for dark energy, though it does not address the…
We show that an inflationary background might be realized by using any p-form non-minimally coupled to gravity. Standard scalar field inflation corresponds to the 0-form case and vector inflation to the 1-form. Moreover, we show that the 2-…
The coupling between spin and torsion in the Einstein-Cartan-Sciama-Kibble theory of gravity generates gravitational repulsion at very high densities, which prevents a singularity in a black hole and may create there a new universe. We show…
The simplest explanation for early time acceleration (inflation) and the late time acceleration indicated by recent data is that they have a common origin. We investigate another generic cosmological implication of this possiblity, that the…
If you fall into a real astronomical black hole (choosing a supermassive black hole, to make sure that the tidal forces don't get you first), then you will probably meet your fate not at a central singularity, but rather in the…
We construct a model of quintessential inflation in Palatini $R^2$ gravity employing a scalar field with a simple exponential potential and coupled to gravity with a running non-minimal coupling. At early times, the field acts as the…
In a variety of inflation models the motion of the inflaton may trigger the production of some non-inflaton particles during inflation, for example via parametric resonance or a phase transition. Particle production during inflation leads…
Understanding the behavior of the universe at large depends critically on insights about the smallest units of matter and their fundamental interactions. Inflationary cosmology is a highly successful framework for exploring these…
In the first part of this paper, we outline the construction of an inflationary cosmology in the framework where inflation is described by a universally evolving scalar field, with the Lagrangian ${\cal L}_\phi=-{1/2}(\partial\phi)^2…
The inflationary paradigm provides a robust description of the peculiar initial conditions which are required for the success of the Hot Big Bang model of cosmology, as well as of the recent precision measurements of temperature…
We deepen the analysis of the cosmological acceleration produced by quantum gravity dynamics in the formalism of group field theory condensate cosmology, treated at the coarse-grained level via a phenomenological model, in the language of…
We consider General Relativity with matter and radiation, one of these fluids being coupled to vacuum. We find that Universe dynamics starts by an inflation phase if the coupled fluid has a negative energy density at early time. Then, there…
We propose a model for early universe cosmology without the need for fundamental scalar fields. Cosmic acceleration and phenomenologically viable reheating of the universe results from a series of energy transitions, where during each…