Faculty Directory

Research Interests

My current research falls in three main categories. The first and probably largest is the study of cosmological inflation and eternal inflation. Inflation is a compelling component of the standard model of cosmology with considerable observational success. Eternal inflation, which is generic in inflation models, describes a situation where inflation goes on forever, ending only locally and thus continually creating “pockets” or “bubbles” of non-inflation that might have diverse properties and one of which might contain our observable universe. (See here for a review article of mine.) My current research, which assesses whether collisions between expanding “bubble universes” could leave an observable imprint on the cosmic microwave background or other cosmological observables.

I'm also very interested in other topics in fundamental physics including: the nature of dark matter and dark energy, foundations of quantum mechanics, black hole evaporation and interiors, the role of information theory in physics, the thermodynamical and statistical arguments in an infinite universe (or multiverse!)

I've also over the years studied issues in galaxy formation and evolution, the intergalactic medium, population III stars, gamma-ray bursts and other topics.

Biography, Education and Training

I received my PhD in Astronomy at Harvard in 2000.  After a three-year stint at the Institute for Advanced Study in Princeton, I joined the UCSC faculty in 2003.