http://arxiv.org/abs/1904.05874
Positivity bounds – the consequences of requiring a unitary, causal, local UV completion – place strong restrictions on theories of dark energy and/or modified gravity. We derive and investigate such bounds for Horndeski scalar-tensor theories and for the first time pair these bounds with a cosmological parameter estimation analysis, using CMB, redshift space distortion, matter power spectrum and BAO measurements from the Planck, SDSS/BOSS and 6dF surveys. Using positivity bounds as theoretical priors, we show that their inclusion in the parameter estimation drastically improves the constraints on dark energy/modified gravity parameters. For the class of models investigated here, only $\lesssim 1\%$ of the previously allowed parameter space survives.
S. Melville and J. Noller
Fri, 12 Apr 19
13/62
Comments: 7 pages