Collaborative Research: New Avenues to Cosmic Acceleration

Regents Of The University Of Michigan - Ann Arbor, Ann Arbor MI

Investigators

Abstract

This project will consist of a theoretical investigation into the nature of dark energy - the agent that causes the accelerated expansion of the universe. This will be accomplished through the twin tools of fundamental particle-physics theory, along with cosmological observations, which include galaxy clustering, the hot and cold spots in the microwave background, and the bending of light by galaxies (gravitational lensing), to improve our knowledge of the mechanism responsible for the current period of acceleration. The project will focus on providing a further stress test of the data to search for any evidence of alternative theoretical explanations for the cosmic acceleration, including modifications of the General Theory of Relativity. Important to the success of this program is an outreach component, which will be coordinated with the SUPA program at Syracuse University. The outreach will include communicating our results to local high school students and more broadly to improving the science curriculum throughout the state of NY and beyond. The quality of data from cosmological probes of Dark Energy (DE) continues to grow at an impressive rate, whereas theoretical progress in our understanding of the underlying mechanism behind cosmic acceleration has been far more modest. As the accuracy of cosmological measurements continues to improve it is crucial to establish an economic and systematic way in which to use data to guide theoretical efforts to reveal the nature of DE. The Effective Field Theory (EFT) of DE provides such an approach. By focusing on the fundamental symmetries of different DE models, rather than the details of a particular model realization, the EFT groups DE models into universal classes based on their general properties. This approach is analogous to the use of EFT methods in particle physics and condensed matter, where it has been very successful in connecting theory and experiment. This project will focus on developing the EFT of DE to establish whether the EFT framework is robust enough to provide a uniform approach to the study of DE. On the practical side, the investigators will work to establish a parameterization of the EFT that is best suited for bridging the gap between fundamental theory and cosmological observations. 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.