Robustness of the inflationary perturbation spectrum to trans-Planckian physics
A. A. Starobinsky
Research Center for the Early Universe, The University of Tokyo, 113-0033 Tokyo, Japan
Landau Institute for Theoretical Physics RAS, 117334 Moscow, Russia
PACS: 04.62.+v, 98.70.Vc, 98.80.Cq
Abstract
It is investigated if predictions of the inflationary scenario
regarding spectra of scalar and tensor perturbations generated from
quantum vacuum fluctuations are robust with respect to a
modification of the dispersion law for frequencies beyond the Planck
scale. For a large class of such modifications of special and general
relativity, for which the WKB condition is not violated at super-high
frequencies, the predictions remain unchanged. The opposite
possibility is excluded by the absence of large amount of created
particles due to the present Universe expansion. Creation of
particles in the quantum state minimizing the energy density of a
given mode at the moment of Planck boundary crossing is prohibited
by the latter argument, too (contrary to creation in the adiabatic
vacuum state which is very small now).