Quantum Gases in an Optical Superlattice

近年来，各种发明和创新使人们有可能在极低的温度下产生稀薄的原子气体，这基本上是已知的宇宙中最冷的物质。通过降低这些气体的温度，人们减少了它们的无序性，从而产生了两种令人兴奋的科学前景。首先，低无序度意味着，在影响原子气体的条件下进行的测量--如电场和磁场，或者加速度和自转--将会有非常小的噪音，从而可以进行更精确的测量。其次，可以通过一种方式来操纵原子气体，即气体中原子之间的相互作用类似于固体材料中电子之间的相互作用。通过这种模仿，人们可以研究材料的性质，这些性质已经被预测出来，但由于真实材料的过度无序和温度而被掩盖了。这一项目通过向这两个前景迈进，促进了科学技术的进步。首席研究员和合作研究员将与研究生和博士后一起开发技术，允许对原子气体进行精确测量。研究人员还将研究模拟复杂材料磁性的原子气体的性质，总体上有助于理解材料和设备中的磁性，这些材料和设备是当今(和未来)信息技术的基础。年轻科学家在这项工作中的核心参与，包括几个来自传统上在物理科学中代表性较低的团体的科学家，直接为美国多样化的科学队伍的培训做出了贡献。具体地说，这个项目关注的是在几束相干光束相交时产生的空间周期强度模式内移动的冷气体的行为。光学图案产生空间周期性势能，类似于电子在固态材料中运动的晶态势能。光学构型可以快速调谐，从而在原子气体中产生各种动力学。这种动力学是本研究的主题，它允许在光学势能范围内对原子运动进行相干控制(与通过物质波干涉法进行精确测量有关)，还揭示了晶体结构倾向于抑制有序性和输运的材料的性质(几何障碍，与材料科学有关)。为了提高人们测量这种动力学的能力，这个项目还调查了如何将计算成像的方法(通过计算方法改进成像)引入到原子气体研究中。最后，自旋动力学被用作一种工具，通过对磁共振成像中使用的方法的修改，测量原子如何在复杂的光学势中扩散，并分离几何受挫对原子运动的影响。

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.