Dark Components and Other Cosmological Mysteries Linked Through Extra Dimensions

Barnard College, New York NY

Investigators

Abstract

A remarkably cohesive description of our universe has emerged that confirms expectations with stunning precision yet simultaneously highlights compelling evidence for physics beyond our current understanding. Over 95% of the universe is in the unknown form of dark energy and dark matter. The scale of the dark energy is 15 orders of magnitude lower than the energy scale of dark matter, yet they fill the universe in comparable proportions today. The dark hierarchy is repeated, intriguingly, in a particle physics hierarchy between the electroweak scale and the Planck scale. Attempts to address the particle hierarchy have invoked the existence of extra dimensions bringing a seemingly unrelated list of cosmological mysteries: How are the dimensions stabilized? Why are only three dimensions large? What could have driven anisotropic inflation in the early universe? The PI proposes that the dark components of the universe are linked to these other seemingly unrelated cosmological mysteries through one simple facet of the cosmos its geometry. The dark energy, she suggests, is Casimir energy, a necessary consequence of quantum mechanics on a finite space. Casimir energy can push the volume of space out or in, depending on the underlying quantum fields. A superposition of fields allows one to balance the forces and stabilize the extra dimensions. The dark matter, following existing suggestions in the literature, could be related to a lightest Kaluza-Klein particle, another direct consequence of ordinary quantum mechanics on a finite space. The hierarchy between scales, stabilization of dimensions, as well as early universe anisotropic inflation can be understood as consequences of these Casimir energies. The broader impacts of this proposal are that each year one or two undergraduate students from Barnard College, a women's college affiliated with Columbia University, will be involved in this research on dark components and extra dimensions. The students will learn to solve simple systems of differential equations that describe the expansion of a higher-dimensional cosmology. A complementary aspect of her project will involve dissemination of the ideas through public outreach supported by Barnard to girls in NYC high schools.