Contrast Interferometry with Quantum Degenerate Ytterbium Gases

量子简并镱气体的对比干涉测量

• 批准号: 1404075
• 负责人: Subhadeep Gupta
• 金额: $ 40.83万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-08-15 至 2017-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1404075&HistoricalAwards=false
• 关键词: Contrast; Interferometry; Quantum; Degenerate; Ytterbium

This grant will support a project to sensitively measure the interaction between light and matter. The experiments will be performed on an atomic gas cooled to very low temperatures in the laboratory, at which point it transforms into an exotic state called a Bose-Einstein condensate (BEC). Like a laser beam, the BEC can be split into multiple parts and then recombined. If the different parts interact differently with light, then this shows up in the properties of the recombined BEC. By using light pulses to split, recombine, and then observe BECs, the group will precisely measure the strength of the light-matter interaction. Their results will provide information regarding possible refinements of the underlying theory of this fundamental process. The atom they are studying (Ytterbium) has potential applications in the development of improved time standards for the global positioning system (GPS) and in the development of quantum computers; both of these efforts involve the sorts of laser-atom control techniques that the group is helping to advance in this project. The students working on the project will gain experience in experimental methods involving atoms, lasers, and electronics, and also be involved in data analysis, modeling, and connecting experimental results with theory. This will form good preparation for them to join the work force in academics and industry as part of the next generation of scientists and engineers. The kinetic energy of an atom recoiling due to absorption of a single photon will be precisely measured as a frequency, by further development of the group's demonstrated contrast interferometry technique with ytterbium BECs. This recoil frequency, combined with other measurements, will accurately determine the fine structure constant alpha, and test the theory of quantum electrodynamics (QED). The fine structure constant is ubiquitous in nature, and QED theory extends across various physics sub-fields. Continued refinement is of fundamental importance. The contrast interferometer utilizes pulsed optical standing waves to split and recombine BECs. The interferometer signal is obtained by monitoring the contrast of the resultant interference pattern via reflection of an optical traveling wave. In addition to testing QED, the group's interferometry technique will advance BEC manipulation methods, and will be used to study many-body phenomena, such as the BEC phase transition.

这笔赠款将支持一个敏感地测量光和物质之间相互作用的项目。这些实验将在实验室中对冷却到极低温度的原子气体进行，在这一点上，它会转变为一种称为玻色-爱因斯坦凝聚体(BEC)的奇异状态。就像激光一样，BEC可以被分成多个部分，然后重新组合。如果不同的部分对光的作用不同，那么这就表现在重组的BEC的性质上。通过使用光脉冲分裂、重组，然后观察BEC，该小组将精确测量光与物质相互作用的强度。他们的结果将提供有关这一基本过程的基本理论可能得到改进的信息。他们正在研究的原子(Yb)在为全球定位系统(Gps)制定改进的时间标准和开发量子计算机方面具有潜在的应用；这两项努力都涉及该小组在该项目中帮助推进的各种激光-原子控制技术。参与该项目的学生将获得涉及原子、激光和电子学的实验方法方面的经验，还将参与数据分析、建模以及将实验结果与理论联系起来。这将为他们加入学术界和工业界的工作大军，成为下一代科学家和工程师的一部分做好准备。通过进一步发展该小组展示的与Yb BECs的对比干涉技术，将精确测量由于吸收单个光子而产生的原子反冲的动能作为一个频率。这个反冲频率，结合其他测量，将准确地确定精细结构常数α，并检验量子电动力学(QED)理论。精细结构常数在自然界中无处不在，QED理论跨越了各个物理子领域。继续完善是至关重要的。对比度干涉仪利用脉冲光学驻波来分解和重组BEC。干涉仪信号是通过监测通过光学行波反射而产生的干涉图案的对比度来获得的。除了测试量子电动力学外，该小组的干涉测量技术还将改进BEC的操纵方法，并将用于研究多体现象，如BEC相变。

项目成果

Three-Path Atom Interferometry with Large Momentum Separation

• DOI: 10.1103/physrevlett.121.133201
• 发表时间: 2018-09-26
• 期刊: PHYSICAL REVIEW LETTERS
• 影响因子: 8.6
• 作者: Plotkin-Swing, Benjamin;Gochnauer, Daniel;Gupta, Subhadeep
• 通讯作者: Gupta, Subhadeep