Bayes' Theorem, Inflation, and the Ekpyrotic Universe
  We calculate the Bayesian evidences for a class of Ekpyrotic universe models,
and compare with a model of single field inflation with a Higgs-type potential.
Combining parsimony and observational constraints, this gives us a systematic
way to evaluate the degree to which Ekpyrotic models are constrained by CMB
data from Planck. We integrate the equations of motion numerically to define a
likelihood using Planck 2018 data and sample this likelihood to obtain Bayesian
evidences. Priors are justified and used to put Ekpyrotic models and inflation
on equal footing. We find reasonable preference for one of the considered
Ekpyrotic models over the others, but that even this one is disfavored compared
with Higgs inflation.
