Supernova constraints on higher-dimensional cosmology with a phantom field

摘要

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 a(t). We show that cosmological solutions of this theory can be usefully parametrized by a single quantity, the lookback time tau(tr) 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 ttr. In the context of the theory, however, these same values of ttr imply that the universe is much older than the oldest observed stars.