Speaker
Shinji Mukohyama
(YITP, Kyoto U & RESCEU, U of Tokyo)
Description
Many dark energy (DE) models are based on a scalar field with timelike
gradient while black holes (BHs) serve as probes of strong gravity. In
this talk we begin with a review of the systematic construction of the
effective field theory (EFT) describing perturbations around the
Minkowski background with a timelike scalar profile and its extension
to cosmological backgrounds, i.e. the ghost condensation and the EFT
of inflation/DE. We then extend the EFT to arbitrary backgrounds. In
this framework a set of consistency relations among EFT coefficients
ensures the spatial diffeo invariance. Finally, we discuss
applications of the general EFT to study perturbations of BH with a
timelike scalar field responsible for DE.