Positivity bounds on dark energy: when matter matters

Mar 11, 2021
6 pages
Published in:
  • JCAP 08 (2021) 018
  • Published: Aug 10, 2021
e-Print:

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Abstract: (IOP)
Positivity bounds — constraints on any low-energy effective field theory imposed by the fundamental axioms of unitarity, causality and locality in the UV — have recently been used to constrain scalar-tensor theories of dark energy. However, the coupling to matter fields has so far played a limited role. We show that demanding positivity when including interactions with standard matter fields leads to further constraints on the dark energy parameter space. We demonstrate how implementing these bounds as theoretical priors affects cosmological parameter constraints and explicitly illustrate the impact on a specific Effective Field Theory for dark energy. We also show in this model that the existence of a standard UV completion requires that gravitational waves must travel superluminally on cosmological backgrounds.
Note:
  • 14+6 pages, 2 figures; v2: minor clarifications added, matches published version
  • dark energy: parameter space
  • effective field theory
  • gravitational radiation
  • gravitation: scalar tensor
  • causality
  • unitarity
  • energy: low
  • field theory: scalar
  • matter: coupling
  • velocity