Research in High Energy Physics and Cosmology

New York University, New York NY

Investigators

Abstract

This award funds the research activities of Professor Matthew B. Kleban at New York University. Some contemporary theories of fundamental physics predict the existence of a so-called "multiverse" containing many distinct bubble universes. These bubbles collide, and collisions with our own bubble produce "cosmic wakes" that travel across our universe, creating specific patterns that are potentially observable with cosmological data from satellite- and ground-based observatories. The detection of such a collision would be a transformative discovery, demonstrating that our observable universe is a tiny part of a vastly larger whole populated by bubbles containing regions of highly exotic physics. It would confirm a prediction of string theory, provide crucial evidence for the nature of "dark energy", and permanently alter our view of the big bang. Professor Kleban will advance a program of research focused on those aspects of string theory and quantum gravity that predict effects --- like bubble collisions --- that can be tested with cosmological observations. Professor Kleban's ongoing research seeks to determine the microphysical origin of cosmic inflation, a period of explosive expansion that took place in the very early universe. As such, Professor Kleban's research advances the national interest by promoting the progress of science in one of its most fundamental directions: the discovery and understanding of new physical laws. Professor Kleban's work will also continue to have broader impact in the form of public lectures and interviews, and in inspiring undergraduate and graduate physics students at NYU. On another front, Prof. Kleban will also train and assist in the professional development of a postdoctoral researcher who will participate in this project. More technically, Prof. Kleban will attempt to realize a model known as "unwinding inflation" in a consistent, stabilized string theory compactification. This model has a number of notable advantages that might make it a plausible explanation for inflation, particularly the fact that it begins spontaneously from a generic meta-stable de Sitter phase in the string landscape. He will also continue his work on inflationary signatures of bubble collisions, tunneling, and other initial-state effects, as well as dynamical features produced during inflation that might indicate its microphysical origin. Lastly, he will continue to study string theory in strongly time-dependent settings, such as cosmology and relativistic brane scattering.