This award supports a broad range of research in gravitational physics, including quantum field theory in curved spacetime, classical general relativity, and cosmology. The specific research topics proposed for investigation include the analysis of a new mathematically rigorous framework for quantum fields in curved spacetime and the ramifications of this framework for interpretation of previous less rigorous calculations and potential new effects. The research program will also include investigations of issues arising in extra-dimensional "brane" models and further study of issues involving gravitational self-force on ?point particles? arising from a recent rigorous derivation of this effect.
The research areas have a common theme: To obtain a deeper understanding of the mathematical and physical properties of classical general relativity and of quantum phenomena occurring in strong gravitational fields. All aspects of this research will involve the direct participation of graduate students. The general areas of research supported by this award are of considerable interest to the public. This interest will be fostered by public lectures and by the PI's participation in the promotion of interdisciplinary conferences and research collaborations between physicists and philosophers and historians of science.
General relativity is the theory of space, time, and gravitation formulated by Einstein nearly a century ago. The main goal of this project was to obtain a deeper understanding of the predictions of general relativity for such phenomena as the motion of bodies, the properties of black holes, and the large scale evolution of our universe. We made significant progress towards determining the corrections to the motion of bodies due to "self-force" effects. We obtained a simple criterion for determining whether a black hole is stable with respect to small perturbations. This criterion strengthened the close association that had previously been known between the laws of black hole physics and the laws of ordinary thermodynamics. We determined the effects that the "lumpiness" of the matter distribution in our universe---i.e., the fact that matter is concentrated in galaxies and clusters of galaxies rather than being spread out in a completely homogeneous manner---can have on the expansion of the universe, and we showed that it cannot account for the observed acceleration of the universe. Five graduate students, one undergraduate student, and two postdoctoral research associates received signifcant training in general relativity and related areas as a result of their work on this project. The PI gave public lectures on black holes in Durban, Capetown, and Vancouver.
