The CMB in a Causal Set Universe

Abstract

We discuss Cosmic Microwave Background constraints on the causal set theory of quantum gravity, which has made testable predictions about the nature of dark energy. We flesh out previously discussed heuristic constraints by showing how the power spectrum of causal set dark energy fluctuations can be found from the overlap volumes of past light cones of points in the universe. Using a modified Boltzmann code we put constraints on the single parameter of the theory that are somewhat stronger than previous ones. We conclude that causal set theory cannot explain late-time acceleration without radical alterations to General Relativity.

5 pages, 2 figures

References in corpus (8)

• A Line of Sight Approach to Cosmic Microwave Background Anisotropies
• Cosmological Perturbation Theory in the Synchronous vs. Conformal Newtonian Gauge
• Cosmological Perturbation Theory in the Synchronous and Conformal Newtonian Gauges
• Forks in the Road, on the Way to Quantum Gravity
• Power Spectra in Global Defect Theories of Cosmic Structure Formation
• Everpresent Lambda
• CMBEASY:: an Object Oriented Code for the Cosmic Microwave Background
• A Strong Constraint on Ever-Present Lambda

Cited by in corpus (5)

• The causal set approach to quantum gravity
• Evolution of Universes in Causal Set Cosmology
• Cosmological Tests of Everpresent $\Lambda$
• The Universe in a Soap Film
• Causal Set Phenomenology