Research/Areas of Interest
Gravitational waves, cosmic strings, energy conditions in general relativity, anthropic reasoning in cosmology.
Biography
I am a research professor in the Tufts Institute of Cosmology. I primarily study gravitational waves and cosmic strings. I am a (full) member of NANOGrav (the North American Nanohertz Observatory for Gravitational Waves), which observes gravitational waves using precision timing of pulsars. I study cosmic strings, in particular their production of gravitational waves, which might enable us to detect the cosmic string network, if it exists. With my collaborators, I have developed a large-scale simulation of cosmic strings and their gravitational wave emission and gravitational back-reaction.
I have worked on the question of exotic phenomena such as superluminal travel and time travel in general relativity. My collaborators and I showed that, subject to certain conditions, a minimally-coupled quantum scalar field obeys the "achronal averaged null energy condition", which prohibits exotic spacetimes.
I have worked on issues of anthropic reasoning in cosmology and how to make sense of the infinite multiverse produced by eternal inflation. I study the structure of eternally inflating universes and also the philosophy of how to get from a model of what actually exists everywhere in the universe to an understanding of what we ourselves should expect to observe.
I'm not working actively on either of these latter projects.
I have worked on the question of exotic phenomena such as superluminal travel and time travel in general relativity. My collaborators and I showed that, subject to certain conditions, a minimally-coupled quantum scalar field obeys the "achronal averaged null energy condition", which prohibits exotic spacetimes.
I have worked on issues of anthropic reasoning in cosmology and how to make sense of the infinite multiverse produced by eternal inflation. I study the structure of eternally inflating universes and also the philosophy of how to get from a model of what actually exists everywhere in the universe to an understanding of what we ourselves should expect to observe.
I'm not working actively on either of these latter projects.