Abstract

The spectra of adiabatic perturbations generated in a realistic double-inflationary model with two massive scalar fields is calculated, including the case when m_hm_l and there exists an intermediate power-law regime a(t)α t^2/3 between the two phases of inflation. In the latter case, the spectrum has a non-flat step-like behaviour in terms of the quantity k^3/2Φ(k) where Φ is a r.m.s. gravitational potential, with larger amplitude at large scales. Transition from the upper plateau to the lower one goes through a very short period of fall-off α k⁻³ (modulated by oscillations) followed by a k⁻¹ behaviour and, finally, by a fall-off α k^−5.5 until the lower plateau is reached. The spectrum of gravitational waves produced in this model is found, too. It has a different structure in the transition region between the two plateaus. Back reaction of generated inhomogeneities on the background is considered in the case of the power-law regime.

Article Outline

• References

*1 This paper was started when one of the authors (A.S.) was a visiting professor at Ecole Normale Supérieure, Paris, under agreement between ENS and Landau Institute for Theoretical Physics, and finished when he was a visiting professor at the Institute of Theoretical Physics, ETH, Zurich, A.S. thanks ENS and ETH for financial support and Profs. E. Brezin, B. Carter and C. Schmidt for their hodpitality in ENS, Observatoire de Paris-Meudon and ETH. D.P. thanks ETH, where this work was completed, for financial support and hospitality.

¹ Permanent address: Lab. de Modèles de Physique Mathématique, Université de Tours, France.

² Permanent address: Landau Institute for Theoretical Physics Russian Academy of Sciences, Moscow 117334, Russian Federation.