Non-perturbative aspects of galileon duality
  We study quantum aspects of the galileon duality, especially in the case of a
particular interacting galileon theory that is said to be dual to a free theory
through the action of a simultaneous field and coordinate transformation. This
would appear to map a theory with multiple vacua to one with a unique vacuum
state. However, by regulating the duality transformation using external
sources, we are able to preserve the full vacuum structure in the dual frame.
By explicitly calculating the one-particle irreducible effective action on a
maximally symmetric background, we identify a semi-classical contribution to
the Wightman functions that has not been taken into account in previous
analyses due to the singular point in the duality map. This may affect its
spectral properties at high energy scales. These observations cast doubt on the
main evidence in support of a non-local UV structure for galileons.
