Accelerating Universe: Landscape or Modified Gravity?

New York University, New York NY

Investigators

Abstract

This award funds the research activities of Professor Sergey Dubovskiy at New York University. The accelerated expansion of the Universe, first observed in 1998, is one of the most surprising discoveries in fundamental physics over the past several decades. Currently, the two most successful theoretical explanations of this observation are either that the laws of gravity change at cosmological distances, or that our Universe is randomly selected from a huge number of universes with different vacuum energies and laws of physics. Definite evidence favoring either of these two proposals will not only have crucial impact on our current picture of the Universe, but may even affect our understanding of the kinds of physics questions which may be amenable to traditional investigations. In his research, Professor Dubovskiy aims to develop methods to test these two alternative scenarios observationally and to develop new ideas capable of explaining the accelerated expansion of the Universe. One critical component of his work is to study the String Axiverse scenario --- a recent proposal by Professor Dubovskiy and his collaborators which describes how the existence of alternative universes may acquire observational support if a plethora of ultra-light particles ("axions") are discovered in our own Universe. An especially intriguing possibility being investigated by Professor Dubovskiy is to use the ongoing observations of astrophysical black holes as a tool to discover the axions predicted in the axiverse scenario. This project is also envisioned to have significant broader impacts. Professor Dubovskiy will involve graduate students and postdocs in his research, and thereby provide critical training to junior physicists beginning research in the fundamental physics. He also intends to give public lectures on his research results, including those aimed at high-school students, and develop new course curricula based on the most recent theoretical and observational results in particle physics and cosmology.