| Nobody knows how to incorporate the classical theory of gravity and the quantum field theory which describes the Standard Model into a single consistent framework. We can, however, study gravity and the Standard Model together with techniques of self-consistent effective field theory, as long as we are content to probe distances larger than the Planck length, 10−33 cm. In this dissertation, I demonstrate a number of predictions coming from the effective field theory approach in two broad areas. First, I show that in curved spaces, gravity can be regulated in a position-dependent way. This regulator is used to understand the thermodynamics of black holes and other gravitational systems, as well as the unification of the Standard Model couplings in certain phenomenologically interesting extra-dimensional models. The second part of this dissertation is concerned with consequences of breaking general coordinate invariance. I provide a simple technique for studying massive gravitons, and use it not only to explain a number of peculiar features of massive gravity in a transparent way but also to pinpoint the reason that models with discrete gravitational dimensions are difficult to construct. These effective field theory investigations leave a number of clues about what properties a fundamental theory of gravity might possess. |
