Model Independent Early Expansion History and Dark Energy

Abstract

We examine model independent constraints on the high redshift and prerecombination expansion history from cosmic microwave background observations, using a combination of principal component analysis and other techniques. This can be translated to model independent limits on early dark energy and the number of relativistic species $N_{\mathrm{eff}}$. Models such as scaling (Doran-Robbers), dark radiation ($\Delta N_{\mathrm{eff}}$), and barotropic aether fall into distinct regions of eigenspace and can be easily distinguished from each other. Incoming CMB data will map the expansion history from $z=0$--$10^5$, achieving subpercent precision around recombination, and enable determination of the amount of early dark energy and valuable guidance to its nature.

11 pages, 8 figures

References in corpus (5)

• Dynamics of dark energy
• Limits on Dark Radiation, Early Dark Energy, and Relativistic Degrees of Freedom
• Future CMB Constraints on Early, Cold, or Stressed Dark Energy
• From Cavendish to PLANCK: Constraining Newton's Gravitational Constant with CMB Temperature and Polarization Anisotropy
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• Insights for Early Dark Energy with Big Bang Nucleosynthesis