Research in String Theory, Supergravity and Cosmology

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This award funds the research activities of Professor Timm Wrase at Lehigh University.More than a hundred years after Albert Einstein discovered his theory of general relativity, we are still working on unifying it with quantum mechanics, the theory that governs the subatomic world. String theory, the leading candidate in this endeavor, has already provided deep insights into what is and what is not possible in a theory of quantum gravity. Some of these insights, like the requirement that the gravitational force be weaker than the other forces in any theoretically consistent universe, are widely accepted. However, there are also other much more speculative ideas. For example, our universe is filled with a mysterious so-called dark energy that counteracts gravity and pushes galaxies apart. It was recently conjectured that such a dark energy has to become weaker over time. As part of his research, Professor Wrase will study this and other related conjectures that make interesting predictions for our own universe. The goal of these investigations is to provide theoretical predictions that can be compared to on-going and future cosmological observations of dark energy and a period of so-called cosmological inflation that is believed to have taken place during the very early universe. This project is also expected to have significant broader impacts. Professor Wrase will involve graduate students and a postdoc in his research, and thereby provide critical training for junior physicists beginning research in this field. He also intends to give public lectures on the topics of his research.More technically, Professor Wrase will study cosmological applications of string theory such as inflation and dS vacua. There are a variety of related swampland conjectures that need to be better understood and made more precise. For example, the status of dS vacua and large-field inflation in string theory are highly debated. Improving our understanding of existing constructions and/or deriving potential no-go theorems will help us in either putting such conjectures on more solid footing or refuting them. This should help in confronting future cosmological observations with improved theoretical predictions for quantities such as the equation of state of dark energy or the tensor-to-scalar ratio during inflation. Another goal of this project is to improve our understanding of supersymmetry breaking in string theory, in particular by studying non-supersymmetric Dp-branes and their connections to non-linear and misaligned supersymmetry.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.