I am interested in many aspects of particle physics gravity and cosmology. My roots are in phenomenological studies of the Standard Model, and more recently I have moved into new areas. At present I am working mainly on gravitational field theory, although I retain interests in much of particle physics:
Gravity as an Effective Field Theory
This has been a long-standing interest of mine, going back to my early work on the subject. My collaborators and I have explored quantum corrections to the gravitational potential and to the bending of light. At present I am interested exploring non-local effects in cosmology and in classical solutions. Also I am interested in the high energy, but still long distance, scattering effects, which bring in very many interesting aspects of field theory.
Quantum gravity as complete quantum field theory All of the Standard Model is based on usual quantum field theory. However each new interaction requires new developments in our QFT techniques (Faddeev Popov ghosts, dimensional regularization, spontaneous symmetry breaking, confinement, etc.). Attempts to use usual QFT for a UV completion of gravity was explored early on, but was largely abandoned, for good reasons, because of serious obstacles. Most of the community moved on to far more exotic alternatives – such as strings, However, after 40 more years of development of QFT, it is possible that some of these obstacles can be overcome using new insights. I am making an attempt to revisit this possibility, and to see if it is truly excluded. At the moment, I can see some ways to circumvent at least some of the previous obstacles. Perhaps this possibility will still be ruled out, but I want to find out.
Field theory and effective field theory
There are many interesting developments going on in Quantum Field Theory in general and also in its relation to effective field theory. My particular expertise is at the interface of QFT and EFT. Some of my recent work has been exploring these connections. There is much more to be done. In particular, I am interested in new methods here, especially if they apply to gravitational field theory.