Theoretical Investigations in Classical and Quantum Gravity

点击翻译按钮获取中文摘要

This project will aim at making significant contributions to several areas within gravitational physics. The topics range from understanding the signals observed by gravitational wave detectors such as NSF's Laser Interferometric Gravitational Wave Observatory (LIGO) and the European Virgo, to studying the nature of black holes and the origin of the Universe. As with the past research supported by ongoing NSF grants, these results are likely to feature as highlights in interdisciplinary conferences, enhancing communication between diverse communities. Research funded by this grant will also add to human resources in STEM disciplines since post-docs and students will acquire diverse skills, including advanced computational and modeling techniques.Research supported by this grant will cover the following main themes: (i) Gravitational waves. Recent discoveries at LIGO have opened a brand new window on the universe. The first set of projects in the proposed research will lay down foundations for production and propagation of gravitational waves in the realistic context of the accelerating universe with dark energy, which we inhabit. (ii) A second set of projects will focus on quantum mechanical properties of black holes. In the classical world of general relativity, black holes are sinks of matter, energy and information. But they evaporate through emission of quantum radiation. There is a general agreement that energy is conserved in this process but there has been an ongoing debate on whether information is still lost, or if it is fully encoded in the quantum radiation that is emitted. Previous work supported by this ongoing NSF grant strongly suggests that quantum gravity effects will remove the `singularity' at the center of the black hole, thereby clearing the way for information --that appeared to be lost there-- to come out. Details of this process will be worked out. (iii) The third project involves the very early universe. In the currently accepted cosmological paradigms, quantum physics is indispensable in the very early phase of the universe, and yet, soon thereafter it is customary to assume that the universe behaves classically, as in general relativity. How this classical behavior can emerge, and why all the subtleties and intricacies of quantum physics can be ignored, are issues of great interest both for foundational reasons and for bridging theory with observations. They will be addressed using a combination of methods from quantum field theory in curved space-times, equations governing dynamics of the early universe and geometric formulation of quantum mechanics. (iv) All three projects discussed above are of deep interest to researchers working at the interface of philosophy and frontiers of physical science, particularly general relativity, cosmology and quantum physics. The results will be discussed at conferences and workshops in these fields, and serve to train young scientists and philosophers in both disciplines.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.