RUI: Precision Cosmological Tests of Varying Fundamental Constants

This award funds the research activities of Professor Daniel Grin at Haverford College.

We are in the era of precision cosmology, where measurements of ancient light (the so-called "cosmic microwave background") have yielded a consensus picture in which the contents of the universe include mysterious dark matter and dark energy. The best framework for understanding dark matter and dark energy involves new ideas in theoretical particle physics which imply that the fundamental ‘constants’ of nature actually vary in space and time.

Professor Grin will develop new methods of testing these scenarios, using data from the cosmic microwave background as well as from other anticipated future measurements. Such research serves the national interest by strengthening fundamental science within the United States. This work will also have significant broader impacts.

The PI will supervise undergraduate research and lead curricular programming that promotes the representation and participation of first-generation and lower-income students in physics courses and research.

More technically, the PI will explore beyond-the-standard-model scenarios (based on string-inspired models) in which the fine-structure constant and electron mass are dynamical variables rather than constants. The work is motivated by puzzling observations of high-redshift quasars. The PI will compute cosmic microwave background statistics in these models, developing the relevant perturbation theory, implementing it in new cosmological Boltzmann codes, developing new statistical methods, obtaining constraints, and conducting forecasts for future ground-based experimental efforts.

This work will be applied to compute the non-Gaussian map signatures of these models, conducting forecasts and possibly tests for such phenomena with current data. The PI will also determine the impact of varying fundamental parameter models on observations of the high-redshift 21-cm emission line from neutral hydrogen.

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.