Experiments with Quantum Gases of Lithium in 1, 2, and 3 Dimensions

William Marsh Rice University, Houston TX

Investigators

Abstract

Research with ultracold atomic gases has greatly expanded by rapid advancement in the ability to trap, cool, and manipulate atomic gases, so that they may be applied to gain better understanding of complex phenomena in condensed matter, material, nuclear, and particle physics. Atomic gases can be cooled to the nano-Kelvin regime where atoms behave more as waves than as classical particles. In this "quantum regime," the atoms exhibit some of the most startling phenomenon known in the physical world, including superfluidity, an analog of superconductivity but with neutral atoms taking the place of electrons. Unlike real materials that possess defects, impurities, and random disorder, the atomic analogs are inherently clean and extraordinarily tunable enabling highly controllable tests of fundamental models. The experiments performed under this grant will use ultra-cold Fermionic lithium atoms, Li-6, to simulate the properties and characteristics of high-temperature superconductors, which are materials of great technological significance, but remain only partially understood. The group will also continue their studies of pairing of mixtures with unequal spin numbers to map out the phase diagram of this incredibly rich system. A particular focus is the "FFLO" phase, where pairing occurs with non-zero center of mass momentum. The FFLO phase has been long studied theoretically, but as of yet there are no clear experimental observations. These experiments will hopefully clarify differences in observations of phase separation with other experiments. Finally using a Bosonic form of lithium, Li-7, the group will investigate Anderson localization, the transition from a superfluid or conductor to an insulator due to disorder. A second experiment in the Boson system will explore a recently proposed dynamical stabilization scheme for creating two-dimensional solitons for the first time. The broader impact of this work is two-fold: firstly, greater understanding of fundamental models of materials may enable the design of real materials with improved performance, such as higher temperature superconductors; and secondly, this research will provide a broad scientific training for the students and post-doctoral scientists engaged in it.