My research encompasses theoretical aspects of effective field theories, modified gravity, extra dimensions/brane worlds, early universe cosmology and screening mechanisms.
One area I work on is massive gravity, the idea that the graviton may have a small mass. Massive gravity has seen a resurgence of interest in recent years, due to progress which has overcome traditional problems. It is a potential avenue for addressing important open questions such as the cosmological constant naturalness problem. Related to massive gravity are the galileons. The galileons are an interesting and novel class of effective field theories which have turned out to be extremely universal. They arise generically when describing the short-distance behavior of the new degrees of freedom introduced during the process of modifying gravity in the infrared, and they arise in describing the brane bending modes of brane worlds. The galileons possess a screening mechanism, called the Vainshtein mechanism, and many other interesting properties. I have been active in exploring formal aspects of massive gravity/galileon theories, in generalizing their nice properties to wider classes of theories, and on subjecting them to tests.
Another aspect of my research focuses on the early universe and inflation. I am interested particularly in the the consequences of non-linearly realized symmetries on inflationary observables. I am also interested in potential alternatives to inflation, such as the psuedo-conformal universe, or conformal scenario, which aim to provide a viable alternative scenario for the early universe rooted in symmetry.