부산대학교 도서관

Summary: We present a cosmological scenario in which the hot big bang universe is produced by the collision of two branes bounding an extra dimension. The collision may occur only once (ekpyrotic scenario), or may repeat itself periodically (cyclic universe). The model addresses the cosmological horizon, flatness and monopole problems and generates a nearly scale-invariant spectrum of density perturbations without invoking a period of inflation. A prediction that distinguishes this scenario from standard inflationary cosmology is a strongly blue gravitational wave spectrum. Consequences for near-future CMB polarization experiments and gravitational wave detectors are discussed.