Galileons on Cosmological Backgrounds
  We construct four-dimensional effective field theories of a generalized DBI
galileon field, the dynamics of which naturally take place on a
Friedmann-Robertson-Walker spacetime. The theories are invariant under
non-linear symmetry transformations, which can be thought of as being inherited
from five-dimensional bulk Killing symmetries via the probe brane technique
through which they are constructed. The resulting model provides a framework in
which to explore the cosmological role that galileons may play as the universe
evolves.
