Decaying dark energy in higher-dimensional gravity

¹ Gravity Probe B, Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305-4085, USA e-mail: overduin@relgyro.stanford.edu
² Astronomy Group, Department of Physics, University of Waterloo, Waterloo, Ontario N2L 3G1, USA
³ Department of Physics and Astronomy, University of Missouri-Columbia, Columbia, MO 65211, USA

Received: 19 April 2007
Accepted: 3 August 2007

Abstract

Aims.We use data from observational cosmology to put constraints on higher-dimensional extensions of general relativity in which the effective four-dimensional dark-energy density (or cosmological “constant”) decays with time.

Methods.In particular we study the implications of this decaying dark energy for the age of the universe, large-scale structure formation, big-bang nucleosynthesis and the magnitude-redshift relation for type Ia supernovae.

Results.Two of these tests (age and the magnitude-redshift relation) place modest lower limits on the free parameter of the theory, a cosmological length scale L akin to the de Sitter radius. These limits will improve if experimental uncertainties on supernova magnitudes can be reduced around .