Predicting the cosmological constant with the scale-factor cutoff measure
Abstract
It is well known that anthropic selection from a landscape with a flat prior distribution of cosmological constant Lambda gives a reasonable fit to observation. However, a realistic model of the multiverse has a physical volume that diverges with time, and the predicted distribution of Lambda depends on how the spacetime volume is regulated. We study a simple model of the multiverse with probabilities regulated by a scale-factor cutoff, and calculate the resulting distribution, considering both positive and negative values of Lambda. The results are in good agreement with observation. In particular, the scale-factor cutoff strongly suppresses the probability for values of Lambda that are more than about ten times the observed value. We also discuss several qualitative features of the scale-factor cutoff, including aspects of the distributions of the curvature parameter Omega and the primordial density contrast Q.
Cite
@article{arxiv.0805.2173,
title = {Predicting the cosmological constant with the scale-factor cutoff measure},
author = {Andrea De Simone and Alan H. Guth and Michael P. Salem and Alexander Vilenkin},
journal= {arXiv preprint arXiv:0805.2173},
year = {2009}
}
Comments
16 pages, 6 figures, 2 appendices