Quantum Gases in an Optical Superlattice

近年来，各种发明和创新使得在极低的温度下产生原子的稀气体成为可能，这基本上是已知宇宙中最冷的物质。通过降低这些气体的温度，人们减少了它们的无序性，从而实现了两个令人兴奋的科学前景。首先，低无序意味着在影响原子气体的条件下进行的测量——比如电场和磁场，或者加速度和旋转——将会有非常小的噪声，从而允许更精确的测量。其次，原子气体可以通过一种类似于固体材料中电子之间相互作用的方式来操纵。通过这种模仿，人们可以研究材料已经被预测出的性能，但由于真实材料的过度无序和温度而被掩盖。本项目通过向这两个方向推进，促进了科学技术的进步。首席研究员和联合研究员，以及研究生和博士后，将开发能够精确测量原子气体和原子气体的技术。研究人员还将研究模拟复杂材料磁性的原子气体的特性，为理解材料和设备的磁性做出贡献，这些材料和设备是当今（以及未来）信息技术的基础。在这项工作中，年轻科学家的核心参与，包括一些来自传统上在物理科学领域代表性不足的群体，直接为培养美国多样化的科学劳动力做出了贡献。具体来说，这个项目的重点是铷和钾原子的冷气体的行为，它们在几个相干光束相交处产生的空间周期性强度模式内移动。光学图样产生一个空间周期势，类似于电子在固态材料中移动时的晶体势。光学结构可以快速调整，从而在原子气体中产生各种动态。这种动力学是本研究的主题，它允许在光势内对原子运动进行相干控制（与通过物质波干涉测量的精确测量有关），并且还揭示了晶体结构倾向于抑制秩序和传输的材料的特性（几何挫折，与材料科学有关）。为了提高测量这种动力学的能力，本项目还研究了如何将计算成像方法（通过计算方法改进成像）引入原子气体的研究。最后，自旋动力学被用作一种工具，通过磁共振成像中使用的方法来测量原子如何在复杂的光势中扩散，并且还可以隔离几何挫折对原子运动的影响。

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.