Spin transport phenomena in ultracold atomic gases

了解粒子的流动，如电子的传递，对于设计和制造设备是至关重要的。随着电子学变得越来越小，经典物理学不再描述传输，量子力学变得重要起来。此外，下一代设备不仅利用材料的电性能，还利用磁性来形成多功能电路元件，例如计算机存储器。具有磁性的粒子流，在微观量子水平上被称为“自旋”，形成了自旋输运场。***我提出了一个探索超冷气体中自旋输运的方案。本提案旨在研究磁（自旋）取向、维数和约束几何在原子气体冷却到接近绝对零度的自旋输运中的作用，在那里可以观察到从经典到量子输运行为的交叉。***详细了解自旋输运对于许多应用是必要的，包括开发使用原子携带和处理信息的设备（“原子电子”设备），基于自旋的传感器技术，以及理解量子状态中的非平衡动力学。更根本的是，自旋输运可以证明微观相互作用如何导致宏观耗散和相干效应。单个双原子相互作用的微妙性质可能导致体系综中显著不同的行为。了解这些微观-宏观联系是自旋输运研究的关键目标。***超冷原子气体非常适合以可控和精确的方式探索自旋动力学，并且通过与其他系统的比较，允许对理论模型进行测试。将看似不同的物理系统与相似的理论描述联系起来，是检验理论和确定其关键组成部分的有力工具。因此，对超冷气体的研究既可以从其他领域的研究中受益，也可以为其他领域的研究提供信息和丰富。***我研究自旋输运的方法是在经典量子交叉中使用超冷铷原子。我们将利用我们以前的工作，使用光学图形技术来创建新的自旋结构和约束几何，包括磁化（自旋）的急剧梯度，二维几何形状和波纹约束几何形状。我们将扩展这些技术来探索扩散，激发和相干在新的制度，和耦合自旋电流到其他现象，如振动或热梯度。所提出的研究计划的影响将有助于对量子自旋输运的全面理解，这将为下一代基于原子的器件提供信息。它还将为学生提供高质量的培训环境，在这里他们将学习广泛的实验、分析和计算技术，同时接受尖端量子技术的培训。

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.