Related papers: The early universe is $\textit{ACT}$-ing $\textit{…
Cosmologists have developed a phenomenally successful picture of structure in the universe based on the idea that the universe expanded exponentially in its earliest moments. There are three pieces of evidence for this exponential expansion…
Next generation of cosmological observations are expected to improve the measurements of several quantities connected to the primordial inflation in the early Universe. These quantities include for example improved measurements for the…
The theory of cosmic inflation has received a great amount of deserved attention in recent years due to it's stunning predictions about the early universe. Alongside the usual cold inflation paradigm, warm inflation has garnered a huge…
Until recently our knowledge of the primordial curvature perturbation was relatively modest. Ever since COBE delivered its map of data we know the scalar spectrum of primordial perturbations is approximately flat, with the power being only…
Observations of the temperature anisotropies in the Cosmic Microwave Background (CMB) radiation show that the models of inflation with the monomial potentials are inconsistent with the allowed $n_s-r$ bounds. However certain monomial…
We present a scenario where a $Z_2$-symmetric scalar field $\phi$ first drives cosmic inflation, then reheats the Universe but remains out-of-equilibrium itself, and finally comprises the observed dark matter abundance, produced by particle…
We study an inflation mechanism based on attractor properties in cosmological evolutions of a spatially flat Friedmann-Robertson-Walker spacetime based on the Einstein-scalar field theory. We find a new way to get the Hamilton-Jacobi…
We propose a model of inflation with a suitable potential for a single scalar field which falls in the wide class of hilltop inflation. We derive the analytical expressions for most of the physical quantities related to inflation and show…
Cosmological inflation remains to be a unique mechanism of generation of plausible initial conditions in the early universe. In particular, it generates the primordial quasiclassical perturbations with power spectrum determined by the…
Inflation is considered one of the cornerstones of modern cosmology. However, the account of the origin of cosmic structure, as provided by the standard inflationary paradigm, is not fully satisfactory. The fundamental issue is the…
In light of the recent results from the Atacama Cosmology Telescope (ACT), which have provided a notable shift in the constraints on $(n_s, r)$ and placed several otherwise viable models of inflation in tension with the latest data, we…
A period of rapidly accelerating expansion is expected in the early Universe implemented by a scalar field slowly rolling down along an asymptotically flat potential preferred by the current data. In this paper, we point out that this…
The standard model of cosmology is based on the hot Big Bang theory and the inflationary paradigm. Recent precise observations of the temperature and polarization anisotropies in the cosmic microwave background and the matter distribution…
Models of cosmic inflation suggest that our universe underwent an early phase of accelerated expansion, driven by the dynamics of one or more scalar fields. Inflationary models make specific, quantitative predictions for several observable…
We revisit the idea that the inflaton may have dissipated part of its energy into a thermal bath during inflation, considering monomial inflationary potentials and three different forms of dissipation rate. Using a numerical Fokker-Planck…
In the early Universe matter can be described as a conformal invariant ultra-relativistic perfect fluid, which does not contribute, on classical level, to the evolution of the isotropic and homogeneous metric. If we suppose that there is…
The mechanism of the initial inflation of the universe is based on gravitationally coupled scalar fields $\phi$. Various scenarios are distinguished by the choice of an {\it effective self--interaction potential} $U(\phi)$ which simulates a…
Cosmology is nowadays going through a true revolution in the quantity and quality of observations that are capable of providing crucial information about the origin and evolution of the universe. In the first years of the next millenium we…
Detailed analyses of the WMAP data indicate possible oscillatory features in the primordial curvature perturbation, which moreover appears to be suppressed beyond the present Hubble radius. Such deviations from the usual inflationary…
With the recent measurements of temperature and polarization anisotropies in the microwave background by WMAP, we have entered a new era of precision cosmology, with the cosmological parameters of a Standard Cosmological Model determined to…