Spin transport phenomena in ultracold atomic gases

点击翻译按钮获取中文摘要

Understanding the flow of particles – such as transport of electrons – is vital in designing and creating devices. As electronics become smaller and smaller, classical physics ceases to describe transport, and quantum mechanics becomes important. Additionally, next-generation devices make use of not just electric properties of materials, but also magnetic properties to form versatile circuit elements, such as computer memory. The flow of particles with magnetic properties, known as "spin" at the microscopic quantum level, forms the field of spin transport.*** I propose a program to explore spin transport in an ultracold gas. This proposal seeks to study the roles of magnetic (spin) orientation, dimensionality, and confinement geometry on spin transport in an atomic gas cooled to near absolute zero, where the crossover from classical to quantum transport behavior can be observed.*** A detailed understanding of spin transport is necessary for many applications, including development of devices that use atoms to carry and process information ("atomtronic" devices), spin-based sensor technology, and understanding out-of-equilibrium dynamics in the quantum regime. More fundamentally, spin transport can demonstrate how microscopic interactions lead to macroscopic dissipative and coherent effects. Subtle properties of individual two-atom interactions can lead to dramatically different behavior in bulk ensembles. Understanding these microscopic-macroscopic connections is a key goal in spin transport studies. *** Ultracold atomic gases are well suited to exploring spin dynamics in a controllable and precise way and, through comparisons with other systems, allow for tests of theoretical models. Linking seemingly disparate physical systems with similar theoretical descriptions is a powerful tool for testing theories and determining their critical components. Thus, studies of ultracold gases can both benefit from, as well as inform and enrich, studies in other fields.*** My approach to studying spin transport uses ultracold Rubidium atoms at the classical-quantum crossover. We will leverage our previous work using optical patterning techniques to create novel spin structures and confinement geometries, including sharp gradients in magnetization (spin), two-dimensional geometries, and corrugated confinement geometries. We will extend these techniques to explore diffusion, excitations, and coherence in new regimes, and couple spin currents to other phenomena like vibrations or thermal gradients. The impact of the proposed research program will be to contribute to a comprehensive understanding of quantum spin transport, which informs next-generation atom-based devices. It will also provide a high quality training environment for students, where they learn a broad array of experimental, analytical, and computational techniques as they train in cutting-edge quantum technology.