2009/02/28 by Michael P. Salem · 22 citations
Chemistry · Physics and Astronomy · #Astrophysics #Black Holes and Theoretical Physics #Chemistry #Computer science #Cosmology and Gravitation Theories #Diamond #Energy (signal processing) #Galaxies: Formation, Evolution, Phenomena #Galaxy #Measure (data warehouse) #Physics #Quantum mechanics #Spacetime #Statistical physics #Theoretical physics #Vacuum energy #astro-ph.CO #hep-ph #hep-th
paper · pdf · doi:10.1103/physrevd.80.023502
published in Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D. Particles and fields 80(2) (American Physical Society) · 9 pages, 3 figures; v2: minor error fixed (results essentially unchanged), reference added; v3: published version, includes a few clarifications
arxiv created 2009/07/02 · openalex publication_date 2009/07/02 · arxiv updated 2010/04/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Arguably a major success of the landscape picture is the prediction of a small, nonzero vacuum energy density. The details of this prediction depend 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.