I am a physicist specialising in the very early universe. More broadly, I am interested in the ways in which speculative physics might influence astrophysical and cosmological processes. The hope is that observations of the universe today might enable us to learn about quantum gravity, string theory, grand unification and other extensions of known physics. More details about my work can be found on my research page. I have also posted slides from talks I've given since about early 2007 here. A nearly complete list of my publications may be found on SPIRES or 2the arXiv.

Here are slides from a talk given at DAMTP on June 20:

This talk explains some new results, from two recent papers (here and here) which tell us what is required to embed dark energy in theories with extra dimensions. These results tell you that eternally accelerating universes can only be embedded in a theory with extra dimensions when some of the energy conditions are violated -- in a variety of cases, the Null Energy Condition must be violated, which is worrisome. The results also show that future constraints on dark energy evolution, and modest improvements in constraints on variation of Newton's constant, will be powerful probes of extra-dimensional physics.

In early June, Paul Steinhardt gave a lecture about these results, and some new work we've been doing, at the PASCOS-O8 conference. You can watch a video of his talk on PIRSA. These results were first presented during a short presentation at the Perimeter Institute this past March, at their Novel Theories of the Early Universe workshop. You can see this earlier talk on video at PIRSA, and the slides at SlideShare.

*About me*

Currently I am a postdoctoral researcher in the Center for Particle Cosmology, in the Department of Physics and Astronomy at the University of Pennsylvania. From 2006-2009, I worked in the Centre for Theoretical Cosmology (CTC), within the Relativity and Gravitation Group, in the Department of Applied Mathematics and Theoretical Physics (DAMTP) at Cambridge University. I also have a departmental page. I earned my PhD in 2006 at Princeton University in the physics department, where my thesis advisor was Paul Steinhardt (also here). Before graduate school I completed the Mathematical Tripos (Part III), thanks to generous support from the Winston Churchill Foundation. I did my undergraduate at Princeton, graduating in 2000.