3 research outputs found
Anisotropic Inflation from Charged Scalar Fields
We consider models of inflation with U(1) gauge fields and charged scalar
fields including symmetry breaking potential, chaotic inflation and hybrid
inflation. We show that there exist attractor solutions where the anisotropies
produced during inflation becomes comparable to the slow-roll parameters. In
the models where the inflaton field is a charged scalar field the gauge field
becomes highly oscillatory at the end of inflation ending inflation quickly.
Furthermore, in charged hybrid inflation the onset of waterfall phase
transition at the end of inflation is affected significantly by the evolution
of the background gauge field. Rapid oscillations of the gauge field and its
coupling to inflaton can have interesting effects on preheating and
non-Gaussianities.Comment: minor changes, references added, figures are modified, conforms JCAP
published versio
Exact Analysis of Level-Crossing Statistics for (d+1)-Dimensional Fluctuating Surfaces
We carry out an exact analysis of the average frequency
in the direction of positive-slope crossing of a given level
such that, , of growing surfaces in spatial
dimension . Here, is the surface height at time , and
is its mean value. We analyze the problem when the surface growth
dynamics is governed by the Kardar-Parisi-Zhang (KPZ) equation without surface
tension, in the time regime prior to appearance of cusp singularities (sharp
valleys), as well as in the random deposition (RD) model. The total number
of such level-crossings with positive slope in all the directions is then
shown to scale with time as for both the KPZ equation and the RD
model.Comment: 22 pages, 3 figure