String cosmology

String Cosmology

String Cosmology

We present a brief review of recent advances in string cosmology. Starting with the Dilaton-Moduli Cosmology (known also as the Pre Big Bang), we go on to include the effects of axion fields and address the thorny issue of the Graceful Exit in String Cosmology. This is followed by a review of density perturbations arising in string cosmology and we finish with a brief introduction to the impact...

String Cosmology

“Old’ String Theory is a theory of one-dimensional extended objects, whose vibrations correspond to excitations of various target-space field modes including gravity. It is for this reason that strings present the first, up to now, mathematically consistent framework where quantum gravity is unified with the rest of the fundamental interactions in nature. In these lectures I will give an introd...

String Cosmology versus Standard and Inflationary Cosmology

This paper presents a review of the basic, model-independent differences between the pre-big bang scenario, arising naturally in a string cosmology context, and the standard inflationary scenario. We use an unconventional approach in which the introduction of technical details is avoided as much as possible, trying to focus the reader’s attention on the main conceptual aspects of both scenarios...

String cosmology and inflation.

Following a suggestion by Gasperini and Veneziano, that String Cosmology can be reconciled with Inflation and, hence, with the Standard Big Bang, we display an analytical solution which possesses four interesting properties: (1) it is non-singular; (2) it distinguishes the dynamics of the external scale factor, a(t), from that of the internal one, b(t); (3) it exhibits a non-monotonic behavior ...