Cosmic Fields: Inflation and Dark Energy

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This award funds the research activities of Professors Marcelo Gleiser and Robert R. Caldwell at the Dartmouth College.One of the most remarkable scientific discoveries of the last decades is that our universe has a history: it emerged from a hot and dense initial state some 13.7 billion years ago and has been expanding and cooling ever since. As is the case with archeologists, modern cosmologists seek clues left over in the present to study the past. In particular, cosmologists seek to uncover the fundamental laws that govern the origin of matter and the evolution of material structures -- from atoms to stars and galaxies -- in the universe. Current observational evidence indicates that the rate at which our universe expands has passed through two anomalous periods when its rate accelerated dramatically: one within the first moments of its existence, and another in current times. The proposed research focuses on both periods of anomalous ultrafast expansion. During the first period, known as cosmic inflation, a fundamental open question is how the universe transitioned from the ultrafast expansion to a more moderate expansion rate. The answer is implicitly related to the mechanism that caused this fast expansion. As it ended, matter was explosively created and complex material structures emerged. Models describing the emergence of these structures and their properties will be developed, and their impact on the cosmic history will be investigated. The second period of fast expansion is believed to have been fueled by the still unknown "dark energy." The research outlined here will attempt to elucidate the fundamental properties of dark energy using techniques from high-energy physics, linking fundamental theory to observational evidence.This project is also envisioned to have significant broader impacts. Professors Gleiser and Caldwell will involve graduate and undergraduate students in their research, and thereby provide critical training to junior physicists beginning research in this field. They also intend to give public lectures on their research results, and write articles and essays in the popular media about cosmology and some of its cutting-edge ideas. Both are active in the public understanding of science through their articles in magazines and newspapers, their appearances in TV documentaries, and also as a blogger for National Public Radio (Gleiser).