UV-completing infrared modifications of gravity
I will present a framework for embedding a class of modified gravity models with interesting infrared properties into a theory with high cutoff scale. The latter cutoff is parametrically unrelated to the scale of the infrared modification and can be as high as the Planck mass. The embedding theory violates Lorentz invariance and is based on the Einstein-aether model of Jacobson and Mattingly or its khronometric version. As explicit examples, I will consider the embeddings of the ghost condensate model and Lorentz violating massive gravity of Dubovsky. In the latter case the embedding mechanism can be viewed as the gravitational analog of the Higgs mechanism in gauge theories. Potential phenomenological applications of the proposed construction will be discussed.