This CAREER grant supports the research of Professor Justin Khoury at the University of Pennsylvania.
As is now increasingly well understood, the energy density of the universe is dominated by contributions from a so-called "dark sector". As part of his research, Professor Khoury will explore the tantalizing prospect that the dark sector includes new light degrees of freedom that mediate long-range forces on cosmological scales, affecting both dark and baryonic matter. To ensure consistency with laboratory and solar system tests of gravity, some screening mechanism is necessary to "hide" these degrees of freedom locally. Professor Khoury therefore aims to probe the theoretical underpinnings of this idea, and fully develop the observational implications of existing screening theories. He also aims to devise novel screening mechanisms within the framework of consistent effective field theories. Professor Khoury will also study a new cosmological framework which he recently developed which might eliminate the need for an early inflationary period of cosmological evolution. This framework, which he calls the "pseudo-conformal universe", provides alternate solutions for many of the classic problems that are also solved by inflation.
Professor Khoury's activities are also envisioned to have significant broader impacts. Professor Khoury will design a freshman seminar for non-science majors, with invited guest lecturers from a new public lecture series hosted jointly by the Center for Particle Cosmology, Penn's Women Studies, and Penn Women's Center. The lecture series will contribute to broader representation of women in science by featuring leading women physicists. Professor Khoury will also build on the series of regular joint workshops he has helped established with Columbia, NYU, and Princeton in order to develop multi-institutional collaborations.
