Relic gravitons from the pre-big bang: what we know and what we do not know

2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/54653I discuss the status of present knowledge about a possible background of relic gravitons left by an early, pre-big bang cosmological epoch, whose existence in the past of our Universe is suggested by the duality symmetries of string theory.34 pages, LATEX, 12 figures included using epsf. See also http://www.to.infn.it/teorici/gasperini/High Energy Physics - TheoryGeneral Relativity and Quantum CosmologyRelic gravitons from the pre-big bang: what we know and what we do not knowtext