相关论文: Just enough inflation: power spectrum modification…

We derive analytic bounds on the shape of the primordial power spectrum in the context of single-field inflation. In particular, the steepest possible growth has a spectral index of $n_s - 1 = 4$ once transients have died down. Its primary…

We investigate inflationary scenarios driven by a class of potentials which are similar in form to those that arise in certain minimal supersymmetric extensions of the standard model. We find that these potentials allow a brief period of…

We study the entire coupled evolution of the inflaton and the scale factor for general initial conditions at a given initial time. The generic early universe evolution has three stages: decelerated fast-roll followed by inflationary fast…

We consider that the pre-inflation era is radiation-dominated, transiting smoothly to the inflationary era. We work out in detail the dynamics of inflaton fluctuations across the phase transition and the proper choices of initial vacuum…

The effect of the initial condition of inflation on the power spectra of scalar and tensor perturbations is estimated assuming a slow-roll inflation model. By defining a more general initial state in inflation particular properties of the…

We consider the effects on the primordial power spectrum of a period of radiation-dominated expansion prior to the inflationary era. If inflation lasts a total of only 60 e-folds or so, the boundary condition for quantum modes cannot be…

We find the best-fit cosmological parameters for a scenario of inflation with only the sufficient amount of accelerated expansion for the $\lambda\phi^4$ potential. While for the simplest scenario of chaotic inflation all observable…

The observational constraints on the primordial power spectrum have tightened considerably with the release of the first year analysis of the WMAP observations, especially when combined with the results from other CMB experiments and galaxy…

Quantum fast-roll initial conditions for the inflaton which are different from the classical fast-roll conditions and from the quantum slow-roll conditions can lead to inflation that last long enough. These quantum fast-roll initial…

In numerical calculations of the primordial power spectrum of perturbations produced during inflation, for very little wavenumber $k$s, to implement the initial conditions required of the perturbation mode functions consistently, we must…

The observed power spectrum of the cosmic microwave background (CMB) is consistent with inflationary cosmology, which predicts a nearly scale-invariant power spectrum of quantum fluctuations of the inflaton field as they exit the Hubble…

Recent cosmic microwave background (CMB) observations put strong constraints on the spatial curvature via estimation of the parameter $\Omega_k$ assuming an almost scale invariant primordial power spectrum. We study the evolution of the…

If the inflationary era is preceded by a radiation dominated era in which the inflaton too was in thermal equilibrium at some very early time then the CMB data places an upper bound on the comoving temperature of the (decoupled) inflaton…

We initially consider two simple situations where inflationary slow roll parameters are large and modes no longer freeze out shortly after exiting the horizon, treating both cases analytically. We then consider applications to transient…

[Abridged] A sharp cut-off in the primordial scalar power spectrum on large scales has been known to improve the fit to the cosmic microwave background (CMB) data when compared to the more standard, nearly scale invariant power spectrum…

We study the amplification of the curvature perturbations due to a small sound speed and find that its origin is different completely from that due to the ultraslow-roll inflation. This is because when the sound speed is very small the…

In this paper we illustrate an interesting example of low scale inflation with an extremely large number of e-foldings. This realization can be implemented easily in hybrid inflation model where usually inflation ends via phase transition.…

In loop quantum cosmology (LQC) the big bang is replaced by a quantum bounce which is followed by a robust phase of super-inflation. Rather than growing unboundedly in the past, the Hubble parameter \emph{vanishes} at the bounce and attains…

The lack of power on large scales (l < 40) might have been observed by the PLANCK satellite. We argue that this putative feature can be explained by a phase of fast roll at the onset of inflation. We show that in the context of single field…

The inflationary and pre-inflationary evolution of scalar modes of cosmological perturbations in a closed universe is analyzed for a loop quantum cosmology model with an inflationary regime consistent with the constraints on inflation…