Negative vacuum energy densities and the causal diamond measure

Abstract

Arguably a major success of the landscape picture is the prediction of a small, non-zero vacuum energy density. The details of this prediction depends in part on how the diverging spacetime volume of the multiverse is regulated, a question that remains unresolved. One proposal, the causal diamond measure, has demonstrated many phenomenological successes, including predicting a distribution of positive vacuum energy densities in good agreement with observation. In the string landscape, however, the vacuum energy density is expected to take positive and negative values. We find the causal diamond measure gives a poor fit to observation in such a landscape -- in particular, 99.6% of observers in galaxies seemingly just like ours measure a vacuum energy density smaller than we do, most of them measuring it to be negative.

9 pages, 3 figures; v2: minor error fixed (results essentially unchanged), reference added; v3: published version, includes a few clarifications

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Cited by in corpus (18)

• Making predictions in the multiverse
• Watchers of the multiverse
• Predictions from Star Formation in the Multiverse
• Global-Local Duality in Eternal Inflation
• Geometric origin of coincidences and hierarchies in the landscape
• Boundary definition of a multiverse measure
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• Dark Matter Annihilations in the Causal Diamond
• Measures for a Multidimensional Multiverse