Chern-Simons-like Theories of Gravity

Gravity is perhaps the most well-known force of nature to the majority of the people, but to a theoretical physicist it remains the most enigmatic one. In modern day physics the gravitational force is related to a number of deep mysteries of the universe in which we live. For instance: what is the correct quantum theory of gravity? How did the universe evolve? What are dark matter and dark energy? One way to look at gravity is as a theory for interacting spin 2 particles called gravitons. These gravitons are thought to be massless particles. In this thesis we explore the possibility and feasibility of theories describing gravitons with a small mass in a simplified setting: in two spatial dimensions. Most notably we consider massive gravitons interacting with massless ones and develop a theoretical framework which is classically self-consistent. The way these models are constructed is novel and it may lead to new cosmological applications if it can be successfully generalized to three spatial dimensions.