Plane waves in the generalized Galileon theory

Understand

We present an exact plane wave solution of the most general shift-symmetric Horndeski (generalized Galileon) theory.

• The solution consists of the scalar part, and the gravitational part with two polarization modes.
• The former is due to the presence of the non-trivial Galileon scalar field, and it is parametrized by an arbitrary function of the light-cone coordinate.
• For a trivial scalar field configuration the solution is equivalent to the plane gravitational wave in General Relativity.