Quantum Gases in an Optical Superlattice

University Of California-Berkeley, Berkeley CA

Investigators

Abstract

In recent years, various inventions and innovations have made it possible to produce dilute gases of atoms at extremely low temperature, essentially the coldest matter in the known Universe. By reducing the temperature of these gases, one reduces their disorder, allowing for two exciting scientific prospects. First, the low disorder implies that measurements made on conditions that effect the atomic gas--such as electric and magnetic field, or acceleration and rotation--will have very little noise, allowing for more precise measurements. Second, the atomic gas can be manipulated in a way that the interactions between atoms in the gas is similar to the interactions between electrons in a solid material. Through such mimicry, one can investigate properties that materials have been predicted to exhibit, but that have been obscured due to the excess disorder and temperature of real materials. This project promotes the progress of science and technology by advancing toward both these prospects. The principal and co-investigator, along with graduate students and postdocs, will develop techniques that allow for precise measurements with and of atomic gases. The researchers will also investigate properties of atomic gases that mimic the magnetic properties of complex materials, contributing in general to the understanding of magnetism in materials and devices that underlie so much of today's (and tomorrow's) information technology. The central involvement of young scientists in this work, including several from groups that have been traditionally underrepresented in the physical sciences, directly contributions toward the training of a diverse scientific workforce in the United States. Specifically, this project focuses on the behavior of cold gases of rubidium and potassium atoms that move within the spatially periodic intensity pattern generated at the intersection of several coherent beams of light. The optical pattern generates a spatially periodic potential that resembles the crystal potential in which electrons move in solid-state materials. The optical configuration can be rapidly tuned, resulting in various dynamics within the atomic gas. Such dynamics, which are the subject of the present investigation, allow for coherent control of atomic motion within the optical potential (relevant to precision measurements through matter-wave interferometry) and also reveal properties of materials in which the crystal structure tends to inhibit order and transport (geometric frustration, relevant to materials science). To improve one's ability to measure such dynamics, this project also investigates how methods of computational imaging (the improvement of imaging through computational methods) may be imported to the study of atomic gases. Finally, spin dynamics are used as a tool to measure how atoms diffuse within complex optical potentials, through an adaptation of methods used in magnetic resonance imaging, and also to isolate the effects of geometric frustration on atomic motion.