Inflaton field potential producing the exactly flat spectrum of adiabatic perturbations
A. A. Starobinsky
Landau Institute for Theoretical Physics RAS, 119334 Moscow, Russia
PACS: 98.80.-k
Abstract
Presented is the exact solution of the problem of finding a
potential of an inflaton scalar field for which adiabatic perturbations
generated during a de Sitter (inflationary) stage in the early
Universe have the exactly flat (or, the Harrison-Zeldovich) initial
spectrum. This solution lies outside the scope of the slow-roll
approximation and higher-order corrections to it. The potential found
depends on two arbitrary physical constants, one of those determines
an amplitude of perturbations. For small (zero) values of the other
constant, a long (infinite) inflationary stage with slow rolling of
the inflaton field exists.