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波浪状或类似颗粒的行为。使用波浪干扰的设备 - 波浪可以相互抵消或相互增强的事实 - 几乎可以对任何事物进行高度敏感的测量：时间，重力，运动或电场和磁场。特别是基于波动干扰的原子钟是人类有史以来最准确的设备，并且具有许多重要的技术应用。时钟和其他干涉仪通过平行测量许多独立原子以增强信号来运行。然后，设备读数会受到测量噪声（投影噪声）的约束，这与一组硬币集合的翻转不同，因为结果并非总是相等数量的头和尾巴。在这里，提议开发方法来产生可用于减少或消除投影噪声的许多原子（所谓的纠缠状态）的相关状态。量子力学允许一个人准备每个硬币单独显示头部或尾部的情况，但是硬币的收集总是显示出相等数量的头部和尾巴。通过证明这种状态的产生，提出的研究计划可以提高原子钟和其他干涉仪的精度，对时间管理，导航和精度测量产生重大影响。拟议的工作将通过培训研究生，并将本科生和杰出的高中生整合到研究工作中来团结研究和教育目标。该项目旨在使用光学谐振器增强的集体原子 - 光相互作用来确定原子集合和光场的非经典（多体纠缠）状态。这样的状态可用于提高原子钟和其他原子干涉仪的精度，超出了标准量子极限。该项目的主要目标是证明在光子射击噪声限制以下行进激光束的功率的非破坏性测量，以创建Schroedinger猫状态或通过检测单个光子的大量集合的强烈自旋挤压状态，并使用此类状态以低于标准量子的原子时钟操作。