Related papers: Non-Flat Power Spectra in the CDM Model
We consider double-inflationary models with two noninteracting scalar fields, a light scalar field $\phi_l$ with potential $\frac{1}{2}m_l^2\phi_l^2$ and a heavy scalar field $\phi_h$ with potential $\frac{\lambda}{n}\phi_h^n$ with $n=2,4$.…
It was proposed that five-dimensional (5D) inflation can blow up the size of a compact dimension from the 5D Planck length to the micron size, as required by the dark dimension proposal, relating the weakness of the actual gravitational…
The mixed cold-hot dark matter cosmological model (CHDM) with $\Omega_{tot}=1$ and a falling power-law initial spectrum of Gaussian adiabatic perturbations ($n>1$) is tested using recent obserbational data. It is shown that its fit to the…
We numerically investigate density perturbations generated in the smooth hybrid new inflation model, a kind of double inflation model that is designed to reproduce the running spectral index suggested by the WMAP results. We confirm that…
We present a consistent one-loop calculation for the inflationary tensor power spectrum in the presence of an excited spectator scalar field using the in-in formalism. We find that the super-horizon primordial power spectrum of the tensor…
In this paper, we suppose that the universe begins in a holographic thermal equilibrium phase with the diverged correlation length, and the phase transition to the radiation phase of standard cosmology goes with the abrupt reducing of…
Cosmological $\alpha$-attractors stand out as particularly compelling models to describe inflation in the very early universe, naturally meeting tight observational bounds from cosmic microwave background (CMB) experiments. We investigate…
In a recent paper [17], we studied the evolution of the background geometry and scalar perturbations in an inflationary, spatially closed Friedmann-Lema\^itre-Robertson-Walker (FLRW) model having constant positive spatial curvature and…
Primordial magnetic fields are generated during inflation by considering actions that break the conformal invariance of the electromagnetic field. To break the conformal invariance, the electromagnetic fields are coupled either to the…
Cosmic inflation, which describes an accelerated expansion of the early Universe, yields the most successful predictions regarding temperature anisotropies in the cosmic microwave background (CMB). Nevertheless, the precise origin of the…
We allow a more general (step-function) form of the primordial power spectrum than the usual featureless power-law Harrison--Zeldovich (with spectral index n=1) power spectrum, and fit it to the latest Cosmic Microwave Background data sets.…
In light of the latest Planck and Atacama Cosmology Telescope (P-ACT) joint results on the primordial scalar power spectrum, we show that the $R^2$ inflation model extended with a non-minimally coupled scalar field $\chi$--namely the…
A second--order perturbation theory approach is developed to calculate temperature anisotropies in the cosmic microwave background. Results are given for open universes and fluctuations corresponding to CDM models with either…
We build upon previous analytical treatments of scalar perturbations in curved inflationary universes to obtain analytical templates for the primordial tensor power spectrum in models with non-zero primordial spatial curvature. These…
Recently, it has been found that complete resolution of the Hubble tension might point to a scale-invariant Harrison-Zeldovich spectrum of primordial scalar perturbation, i.e. $n_s=1$ for $H_0\sim 73$km/s/Mpc. We show that for well-known…
A possible origin of the anomalous dip and bump in the primordial power spectrum, which are reconstructed from WMAP data corresponding to the multipole $\ell=100\sim 140$ by using the inversion method, is investigated as a consequence of…
We perform a cosmological analysis in which we allow the primordial power spectrum of scalar perturbations to assume a shape that is different from the usual power-law predicted by the simplest models of cosmological inflation. We…
To test the primordial power spectra predicted by a double inflationary model with a break of amplitude $\Delta=3$ at a scale of $2\pi/k\approx 10 \hm$ and CDM as dominant matter content, we perform PM simulations with 128$^3$ particles on…
We study the effects of a general type of features of the inflaton potential on the spectrum and bispectrum of primordial curvature perturbations. These features correspond to a discontinuity in the $n$-th order derivative of the potential…
(Shortened abstract) While a featureless, nearly scale invariant, primordial scalar power spectrum fits the most recent CMB data rather well, certain features in the spectrum are known to lead to a better fit to the data (although, the…