PREPRINT
FB18C621-CF04-4E51-9705-A7757E0A4623

# Status of String Cosmology: Phenomenological Aspects

M. Gasperini
arXiv:hep-th/9509127

Submitted on 23 September 1995

## Abstract

I report recent studies on the evolution of perturbations in the context of the pre-big-bang" scenario typical of string cosmology, with emphasis on the formation of a stochastic background of relic photons and gravitons, and its possible direct/indirect observable consequences. I also discuss the possible generation of a thermal microwave background by using, as example, a simple gravi-axio-dilaton model whose classical evolution connects smoothly inflationary expansion to decelerated contraction. By including the quantum back-reaction of the produced radiation the model eventually approaches the standard radiation-dominated (constant dilaton) regime.

## Preprint

Comment: 37 pages, Plain TEX, 3 figures available by fax upon request, to appear in Proc. of the Erice School on "String gravity and physics at the Planck scale" (Erice, 8-19 September 1995)

Subjects: High Energy Physics - Theory; Astrophysics; General Relativity and Quantum Cosmology