5 research outputs found
Gravitational waves in an anomaly-induced inflation
The behaviour of gravitational waves in the anomaly-induced inflationary
phase is studied. The metric perturbations exhibit a stable behaviour, with a
very moderate growth in the amplitude of the waves. The spectral indice is
computed, revealing an almost flat spectrum.Comment: 4 pages. Talk presented at IRGA 2003 (Renormalization Group and
Anomalies in Gravitation and Cosmology, Ouro Preto, Brazil, 16-23 March,
2003
Quantum photon emission from a moving mirror in the nonperturbative regime
We consider the coupling of the electromagnetic vacuum field with an
oscillating perfectly-reflecting mirror in the nonrelativistic approximation.
As a consequence of the frequency modulation associated to the motion of the
mirror, low frequency photons are generated. We calculate the photon emission
rate by following a nonperturbative approach, in which the coupling between the
field sidebands is taken into account. We show that the usual perturbation
theory fails to account correctly for the contribution of TM-polarized vacuum
fluctuations that propagate along directions nearly parallel to the plane
surface of the mirror.
As a result of the modification of the field eigenfunctions, the resonance
frequency for photon emission is shifted from its unperturbed value.Comment: 11 pages, 3 figures. To be published in Optics Communication
On the stability of the anomaly-induced inflation
We analyze various phases of inflation based on the anomaly-induced effective
action of gravity (modified Starobinsky model), taking the cosmological
constant Lambda and k=0, +/- 1 topologies into account. The total number of the
inflationary e-folds may be enormous, but at the last 65 of them the inflation
greatly slows down due to the contributions of the massive particles. For the
supersymmetric particle content, the stability of inflation holds from the
initial point at the sub-Planck scale until the supersymmetry breaks down.
After that the universe enters into the unstable regime with the eventual
transition into the stable FRW-like evolution with small positive cosmological
constant. It is remarkable, that all this follows automatically, without
fine-tuning of any sort, independent on the values of Lambda and k. Finally, we
consider the stability under the metric perturbations during the last 65
e-folds of inflation and find that the amplitude of the ones with the
wavenumber below a certain cutoff has an acceptable range.Comment: 27 pages, LaTeX, 8 figures, some misprints correcte