Entangled States of Light and Atoms for Measurements Below the Standard Quantum Limit

用于低于标准量子极限测量的光和原子纠缠态

• 批准号: 1505862
• 负责人: Vladan Vuletic
• 金额: $ 45万
• 依托单位: Massachusetts Institute of Technology
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-01 至 2018-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1505862&HistoricalAwards=false
• 关键词: Entangled; States; Light; Atoms; Measurements

Quantum mechanics tells us that both matter and light can exhibit wave-like or particle-like behavior. Devices that use the interference of waves--the fact that waves can cancel each other out or enhance each other--enable highly sensitive measurements of almost anything: time, gravity, motion, or electric and magnetic fields. In particular, atomic clocks, that are based on wave interference, are the most accurate devices ever made by mankind, and have many important technological applications. Clocks and other interferometers operate by measuring many independent atoms in parallel to enhance the signal. The device readout is then subject to measurement noise (projection noise), not unlike the flipping of a collection of coins where the outcome is not always an equal number of heads and tails. Here it is proposed to develop methods to produce correlated states of many atoms (so-called entangled states) that can be used to reduce or eliminate the projection noise. Quantum mechanics allows one to prepare a situation where each coin individually still randomly shows head or tail, but the collection of coins always shows an equal number of heads and tails. By demonstrating the generation of such states, the proposed research program could boost the precision of atomic clocks and other interferometers, with significant implications for timekeeping, navigation, and precision measurements. The proposed work will unite research and educational goals by training graduate students, and by integrating undergraduate students and exceptional high-school students into the research effort. This project is aimed at the deterministic preparation of non-classical (many-body entangled) states of atomic ensembles and of light fields using collective atom-light interaction enhanced by an optical resonator. Such states can be used to improve the precision of atomic clocks and other atom interferometers beyond the standard quantum limit. The main goals of the project are to demonstrate a non-destructive measurement of the power of a traveling laser beam below the photon shot noise limit, to create Schroedinger cat states or strongly spin squeezed states of a large atomic ensemble via the detection of a single photon, and to use such states to operate an atomic clock below the standard quantum.

量子力学告诉我们，物质和光都可以表现出类似波或类似粒子的行为。利用波的干涉（波可以相互抵消或相互增强）的设备可以对几乎任何东西进行高灵敏度的测量：时间，重力，运动或电场和磁场。特别是基于波干涉的原子钟，是人类有史以来制造的最精确的装置，具有许多重要的技术应用。时钟和其他干涉仪通过并行测量许多独立的原子来增强信号。然后，设备读数会受到测量噪音（投影噪音）的影响，这与翻转一组硬币不同，其中结果并不总是正面和反面的数量相等。在这里，它建议开发的方法来产生关联态的多个原子（所谓的纠缠态），可以用来减少或消除投影噪声。量子力学允许我们准备这样一种情况：每个硬币仍然随机地显示正面或反面，但硬币的集合总是显示相等数量的正面和反面。通过证明这种状态的产生，拟议的研究计划可以提高原子钟和其他干涉仪的精度，对计时，导航和精密测量具有重大意义。拟议的工作将通过培养研究生，并通过将本科生和优秀高中生纳入研究工作，将研究和教育目标结合起来。该项目的目的是确定性的准备非经典（多体纠缠）状态的原子系综和光场使用集体原子-光相互作用增强的光学谐振腔。这种状态可以用来提高原子钟和其他原子干涉仪的精度，使其超过标准量子极限。该项目的主要目标是展示在光子散粒噪声极限以下的行进激光束功率的非破坏性测量，通过检测单个光子来创建薛定谔猫态或大原子系综的强自旋压缩态，并使用这些状态在标准量子以下操作原子钟。