From Planck data to Planck era: Observational tests of Holographic Cosmology

From Planck data to Planck era: Observational tests of Holographic Cosmology We test a class of holographic models for the very early universe against cosmological observations
and find that they are competitive to the standard ΛCDM model of cosmology. These models are
based on three dimensional perturbative super-renormalizable Quantum Field Theory (QFT), and
while they predict a different power spectrum from the standard power-law used in ΛCDM, they
still provide an excellent fit to data (within their regime of validity). By comparing the Bayesian
evidence for the models, we find that ΛCDM does a better job globally, while the holographic
models provide a (marginally) better fit to data without very low multipoles (i.e. l . 30), where
the dual QFT becomes non-perturbative. Observations can be used to exclude some QFT models,
while we also find models satisfying all phenomenological constraints: the data rules out the dual theory being Yang-Mills theory coupled to fermions only, but allows for Yang-Mills theory coupled to non-minimal scalars with quartic interactions. Lattice simulations of 3d QFT’s can provide non-perturbative predictions for large-angle statistics of the cosmic microwave background, and
potentially explain its apparent anomalies.