Related papers: Suppressing CMB Quadrupole with a Bounce from Cont…
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…
The Cosmic Microwave Background (CMB) anisotropy power on the largest angular scales observed both by WMAP and COBE DMR appears to be lower than the one predicted by the standard model of cosmology with almost scale free primordial…
Recent Planck data show the anomalies of CMB fluctuations on large angular scales, which confirms the early observations by WMAP. We continue studying an inflationary model, in which before the slow roll inflation the universe is in a…
The recent observation of the cosmic microwave background anisotropy by the WMAP confirmed that the lower multipoles are considerably suppressed. From the standpoint of the cosmic variance, it is nothing but a statistical accident.…
Probing correlations among short and long-wavelength cosmological fluctuations is known to be decisive for deepening the current understanding of inflation at the microphysical level. Spectral distortions of the CMB can be caused by…
The cosmic microwave background (CMB) temperature anisotropies from primordial magnetic fields are studied. In addition to the known passive and the compensated mode we discuss an inflationary magnetic mode in the curvature perturbation,…
Recent released WMAP data show a low value of quadrupole in the CMB temperature fluctuations, which confirms the early observations by COBE. In this paper we consider a model of two inflatons with different masses, $V(\phi_1,\phi_2)={1\over…
The low quadrupole of the cosmic microwave background (CMB), measured by COBE and confirmed by WMAP, has generated much discussion recently. We point out that the well-known correlation between temperature and polarization anisotropies of…
We generalize the treatment of inflationary perturbations to deal with the non-Markovian colored noise emerging from any realistic approach to stochastic inflation. We provide a calculation of the power-spectrum of the gauge-invariant…
It is well known that processes of first order phase transitions may have occurred in the inflationary era. If one or more occurred well before the end of inflation, the nucleated bubbles are stretched to large scales and the primordial…
According to inflationary cosmology, the CMB anisotropy gives an opportunity to test predictions of new physics hypotheses. The initial state of quantum fluctuations is one of the important options at high energy scale, as it can affect…
Within the effective field theory of inflation, an initialization of the classical dynamics of the inflaton with approximate equipartition between the kinetic and potential energy of the inflaton leads to a brief fast roll stage that…
Cosmic microwave background (CMB) anisotropy may result from both scalar and tensor perturbations. For a sufficiently narrow range of angular scales, CMB perturbations can be characterized by four parameters. Results from the Cosmic…
Inflation creates both scalar (density) and tensor (gravity wave) metric perturbations. We find that the tensor mode contribution to the CMB anisotropy on large-angular scales can only exceed that of the scalar mode in models where the…
The temperature perturbations of the cosmic microwave background radiation (CMB) appear systematically suppressed, at large angular scales, with respect to the prediction of the LambdaCDM concordance model. This behavior might be a glimpse…
We explicate the origin of the temperature quadrupole in the adiabatic dark energy model and explore the mechanism by which scale invariant isocurvature dark energy perturbations can lead to its sharp suppression. The model requires…
The first year results of WMAP tentatively indicate running of the spectral index as well as a deficit of power in the low multipoles in the CMB spectrum. The former can be rather easily understood in the noncommutative inflation model, and…
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…
Recent Planck measurements show some CMB anomalies on large angular scales, which confirms the early observations by WMAP. We show that an inflationary model, in which before the slow-roll inflation the Universe is in a superinflationary…
The possibility to have an infinite open inflationary universe inside a bubble of a finite size is one of the most interesting realizations extensively discussed in the literature. The original idea was based on the theory of tunneling and…