Λ=0 Cosmology of a Brane-like Universe

Abstract

We examine the possibility that Friedman-Robertson-Walker evolution is governed by an effective (rather then by the actual) energy density. A concrete example is provided by $Λ=0$ Regge-Teitelboim cosmology, where critical cosmology only requires subcritical matter density $(Ω_{m}<1)$, and the age of a flat matter dominated Universe gets enhanced by a factor of 9/8. Dual to the mature dilute Universe is the embryo Universe, the evolution of both is governed by $P_{eff}=-{1/9}ρ_{eff}$.