Collaborative Research: Cold Rydberg Atoms

合作研究：冷里德伯原子

• 批准号: 1607335
• 负责人: Thomas Carroll
• 金额: $ 17.48万
• 依托单位: Ursinus College
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-09-01 至 2020-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1607335&HistoricalAwards=false
• 关键词: Collaborative; Research; Cold; Rydberg; Atoms

The goals of this collaborative project are twofold: first, to understand and control the movement of energy among strongly connected groups of atoms, and second, to improve an experimental technique for measuring the energy distribution among these atoms. These general goals are present in many areas of science (for example, in the study of the transport of energy in metals) but they are often difficult to realize for the simple reason that solids are densely packed with atoms and typically opaque. This work will be done in an "ultracold gas" of atoms that are cooled so that they move slowly like the atoms in a solid, but are at low density. Collections of these atoms are transparent and can be probed and controlled with lasers. If the outer electrons in these atoms are excited to high energy levels, then the atoms can exchange energy in ways that are similar to other quantum systems. Using a combination of simulation and experimental imaging techniques, the transport of energy will be measured. In this way, the project aims to create and study atomic systems that will yield insight into both fundamental quantum mechanics and the behavior of materials. The second goal of this project concerns a widely used experimental technique in which the energy level of an electron is measured by using a rapidly increasing electric field to rip off, or ionize, the outermost electron from the atom. The stripped electron is accelerated to a detector and the resulting signal is characteristic of the electron's original energy level. However, the ionization process is complex and nearby energy levels produce signals which are indistinguishable. This project will precisely shape the electric field pulse so that the signals from closely spaced energy levels can be distinguished, making new experiments possible in many areas of atomic physics.In this project, the valence electron of ultracold rubidium atoms in a magneto-optical trap is excited to a weakly bound state of high principle quantum number, or Rydberg state. Both the spatial distribution of the atoms and the internal states to which they are excited are precisely controlled. The atoms in such a sample exchange energy through a dipole-dipole interaction. Building upon earlier work implementing "state selective field ionization" with two parallel cylinders of atoms excited to two different Rydberg states, other geometries and state distributions will be explored. As the electron's amplitude traverses the many avoided crossings on the way to ionization it splits due to Landau-Zener transitions and spreads throughout many Stark levels, complicating the identification of the original electronic energy level. Previous attempts at manipulating the electron's path to ionization have focused on coarsely determining the slope of the electric field ramp. Since there are hundreds of avoided crossings on the way to ionization, a genetic algorithm will be used to design the electric field ramp. In addition, recent simulations have revealed the possibility of observing the anisotropic nature of the dipole-dipole interaction as well as Anderson localization.

这个协作项目的目标是双重的：首先，了解和控制强烈联系的原子组之间的能量运动，其次，以改善一种实验技术来测量这些原子之间的能量分布。这些一般目标存在于许多科学领域（例如，在金属中能量运输的研究中），但是由于固体密集包装有原子和通常不透明的简单原因，它们通常很难实现。这项工作将以冷却的原子的“超低气体”进行，使它们像原子一样缓慢移动，但处于低密度。这些原子的集合是透明的，可以用激光探测和控制。如果这些原子中的外电子兴奋至高能水平，那么原子可以以类似于其他量子系统的方式交换能量。结合模拟和实验成像技术，将测量能量的运输。通过这种方式，该项目旨在创建和研究原子系统，以洞悉基本量子力学和材料行为。该项目的第二个目标涉及一种广泛使用的实验技术，其中通过使用快速增加的电场撕下或电离原子中的最外部电子来测量电子的能级。剥离的电子被加速到检测器，所得信号是电子原始能级的特征。但是，电离过程很复杂，附近的能级产生的信号是无法区分的。该项目将精确地塑造电场脉冲，以便可以区分来自离子物理学的许多领域的新实验。精确控制原子的空间分布和所激发的内部状态。这种样品中的原子通过偶极 - 偶极相互作用交换能量。在实施“州选择性场电离”的早期工作的基础上，将探索两个平行的原子缸对两个不同的rydberg州激发的原子缸，将探索其他几何和州分布。随着电子的振幅越过许多避免的交叉口，由于Landau-Zener的过渡并在许多鲜明的水平上传播，因此它分裂了，这使原始电子能级的识别变得复杂。以前试图操纵电子电离路径的尝试重点是确定电场坡道的斜率。由于在进行电离的途中有数百个避免的交叉口，因此将使用遗传算法来设计电场坡道。此外，最近的模拟揭示了观察偶极 - 偶极相互作用以及安德森本地化的各向异性性质的可能性。