Supernova constraints on higher-dimensional cosmology with a phantom field

Abstract

We use observational data on the magnitude-redshift relation for Type Ia supernovae (SNeIa) together with constraints on the ages of the oldest stars to rule out a higher-dimensional extension of General Relativity with a negative kinetic energy scalar field. This theory is of considerable physical interest because it produces accelerated expansion at both early and late times with a single new field, as in quintessential inflation scenarios. It is also of mathematical interest because it is characterized by an analytic expression for the macroscopic scale factor [Formula: see text]. We show that cosmological solutions of this theory can be usefully parametrized by a single quantity, the lookback time [Formula: see text] corresponding to the transition from deceleration to acceleration. Supernovae data from the recently released Supernova Cosmology Project (SCP) Union 2.1 compilation single out a narrow range of values for [Formula: see text]. In the context of the theory, however, these same values of [Formula: see text] imply that the universe is much older than the oldest observed stars.