Supernova constraints on higher-dimensional cosmology with a phantom field

TL;DR

This paper tests a higher-dimensional cosmological model with a phantom field against supernova data and star age constraints, finding it incompatible with observations due to age discrepancies.

Contribution

It demonstrates that a specific higher-dimensional phantom field model cannot fit supernova and stellar age data simultaneously.

Findings

Supernova data constrains the transition time from deceleration to acceleration.

The model predicts an age of the universe incompatible with the oldest stars.

The theory is ruled out by observational age constraints.

Abstract

We use observational data on the magnitude-redshift relation for Type Ia supernovae 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 $\tau_{\text{tr}}$ corresponding to the transition from deceleration to acceleration. Supernovae data from the recently released Supernova Cosmology Project Union 2.1 compilation single out a narrow range of values for $\tau_{\text{tr}}$. In the context of the theory, however, these same values of $\tau_{\text{tr}}$ imply that the universe is much older than the oldest observed stars.