A Strong Constraint on Ever-Present Lambda

Abstract

We show that the causal set approach to creating an ever-present cosmological 'constant' in the expanding universe is strongly constrained by the isotropy of the microwave background. Fluctuations generated by stochastic lambda generation which are consistent with COBE and WMAP observations are far too small to dominate the expansion dynamics at z<1000 and so cannot explain the observed late-time acceleration of the universe. We also discuss other observational constraints from the power spectrum of galaxy clustering and show that the theoretical possibility of ever-present lambda arises only in 3+1 dimensional space-times.

5 pages, minor additions, published version

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• Echoes of Asymptotic Silence in Causal Set Quantum Gravity
• Everpresent Lambda - II: Structural Stability
• The CMB in a Causal Set Universe
• The Universe in a Soap Film
• Dark energy due to effective quantum field theory
• Causal Set Phenomenology
• Quantum theory, noncommutative gravity, and the cosmological constant problem
• On cosmological constant in Causal Set theory