29 research outputs found
Density Perturbations of Thermal Origin During Inflation
We study thermally induced density perturbations during inflation. This
scenario is characterized by two thermodynamical conditions: (1) The primordial
perturbations originate in the epoch when the inflationary universe contains a
thermalized heat bath. (2) The perturbations of the inflationary scalar field
are given by the fluctuation-dissipation relation. We show that the spectrum of
the primordial perturbations is of power law, but tilted, and there is a
relation between the amplitude and the index of the power spectrum. Aside from
the mass scale of the inflation, the amplitude-index relation does not depend
on other parameters like -factor. These results are found to be well
consistent with observations of the temperature fluctuations of cosmic
microwave background if the mass scale of the inflation is about GeV.
Instead of the purely adiabatic case, the consequent density perturbation is an
admixture of adiabatic and isocurvature one. Therefore, the detection of
super-Hubble suppression of the spectrum would be effective for further
discrimination between the thermally originated models and others.Comment: 21 pages, 7 postscript figures, using revte
Production of high stellar-mass primordial black holes in trapped inflation
Trapped inflation has been proposed to provide a successful inflation with a
steep potential. We discuss the formation of primordial black holes in the
trapped inflationary scenario. We show that primordial black holes are
naturally produced during inflation with a steep trapping potential. In
particular, we have given a recipe for an inflaton potential with which
particle production can induce large non-Gaussian curvature perturbation that
leads to the formation of high stellar-mass primordial black holes. These
primordial black holes could be dark matter observed by the LIGO detectors
through a binary black-hole merger. At the end, we have given an attempt to
realize the required inflaton potential in the axion monodromy inflation, and
discussed the gravitational waves sourced by the particle production.Comment: 6 pages, 5 figures, match the version accepted by JHE
The origin of scale-scale correlations of the density perturbations during inflation
We show that scale-scale correlations are a generic feature of slow-roll
inflation theories. These correlations result from the long-time tails
characteristic of the time dependent correlations because the long wavelength
density perturbation modes are diffusion-like. A relationship between the
scale-scale correlations and time-correlations is established providing a way
to reveal the time correlations of the perturbations during inflation. This
mechanism provides for a testable prediction that the scale-scale correlations
at two different spatial points will vanish.Comment: Accepted for publication, International Journal of Modern Physics,
vol. 8 No.6 (Dec 1999