\Lambda=0 Cosmology of a Brane-like Universe

TL;DR

This paper explores a a0Lambda=0a0 cosmological model where the universe's evolution is driven by an effective energy density, leading to a longer universe age and novel dynamics in a brane-like universe setting.

Contribution

It introduces a a0Lambda=0a0 cosmology framework based on Regge-Teitelboim theory, highlighting how effective energy density influences universe evolution.

Findings

Critical cosmology with a0Omega_m<1a0 is possible.

The universe's age can be increased by a factor of 9/8.

Duality between mature and embryo universes governed by a0P_{eff}=-{1/9} ho_{eff}a0.

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 $\Lambda=0$ Regge-Teitelboim cosmology, where critical cosmology only requires subcritical matter density $(\Omega_{m}<1)$, 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 $P_{eff}=-{1/9}\rho_{eff}$.