Related papers: Entangled Scalar and Tensor Fluctuations during In…
How sensitive are the predictions of inflation to pre-inflationary conditions when the number of efolds of inflation is not too large? In an attempt to address this question, we consider a simple model where the inflationary era is preceded…
For the inflaton perturbations it is shown that the evolution of the difference between the spectral indices can be translated into information on the scale dependence of the tensor to scalar amplitudes ratio, $r$, and how the scalar field…
We argue that the preferred classical variables that emerge from a pure quantum state are determined by its entanglement structure in the form of redundant records: information shared between many subsystems. Focusing on the early universe,…
We compute the spectrum of scalar and tensor metric perturbations generated, as amplified vacuum fluctuations, during an epoch of dilaton-driven inflation of the type occurring naturally in string cosmology. In the tensor case the…
The measurement of B-mode polarization of the cosmic microwave background at large angular scales by the BICEP experiment suggests a stochastic gravitational wave background from early-universe inflation with a surprisingly large amplitude.…
Spectrum of initial scalar and tensor perturbations created during an inflationary stage producing a closed or open FRW universe now is discussed. In the closed case, the CMB temperature anisotropy ${\Delta T/T}$ generated by scalar…
Recently, it was proposed that a small true vacuum universe can inflate spontaneously, in principle. Furthermore, there should be matter creation in vacuum inflation due to quantum fluctuations, and the matter created will influence the…
Future cosmic microwave background polarization experiments will search for evidence of primordial tensor modes at large angular scales, in the multipole range $4 \leq \ell \leq 50.$ Because in that range there is some mild evidence of…
How well can we constrain the initial quantum state of metric perturbations sourced during inflation? We exhibit an interesting new class of quantum states that entangle the scalar metric perturbations {\zeta} with other fields such as…
The linear and quadratic perturbations for a scalar-tensor model with non-minimal coupling to curvature, coupling to the Gauss-Bonnet invariant and non-minimal kinetic coupling to the Einstein tensor are developed. The quadratic action for…
In the context of the open inflationary universe, we calculate the amplitude of quantum fluctuations which deform the bubble shape. These give rise to scalar field fluctuations in the open Friedman-Robertson-Walker universe which is…
We show that if inflation lasted just longer than the required 60 or so e-folds $N$ both scalar and tensor contributions to the Cosmic Microwave Background (CMB) power spectra are expected to show a cut-off. However the behaviour of the…
We consider a quantum deformation of the wave equation on a cosmological background as a toy-model for possible trans-Planckian effects. We compute the power spectrum of scalar and tensor fluctuations for power-law inflation, and find a…
We consider the spectrum of primordial fluctuations produced by inflationary models where the inflaton potential is the sum of two exponential terms. A wide range of spectra result, with the only constraint being that the scalar spectrum…
Power spectra always play an important role in the theory of inflation. In particular, the ability to reproduce the galaxy matter power spectrum and the CMB temperature angular power spectrum coefficients to high accuracy is often…
The scalar and tensor fluctuations generated during inflation can be correlated, if arising from the same underlying mechanism. In this paper we investigate such correlation in the model of axion inflation, where the rolling inflaton…
We revisit the possibility of producing observable tensor modes through a continuous particle production process during inflation. Particularly, we focus on the multi-field realization of inflation where a spectator pseudo-scalar $\sigma$…
The effect of the length of inflation on the power spectra of scalar and tensor perturbations is estimated using the power-law inflation model with a scale factor of a(t) = t^q. Considering various pre-inflation models with…
The prediction of a nearly scale-invariant spectrum of curvature and tensor fluctuations is among the main features of cosmic inflation. The current measurements of the primordial fluctuations in the cosmic microwave background (CMB)…
It is plausible that the scalar density perturbations are created by a relatively low scale model of inflation which predicts the CMB anisotropy and excites Standard Model baryon and cold dark matter, but negligible gravity waves.…