Electron Magnetic Moment, Fine Structure Constant, Mass Ratios, Laser Spectroscopy and QED

电子磁矩、精细结构常数、质量比、激光光谱和 QED

• 批准号: 0555508
• 负责人: Gerald Gabrielse
• 金额: $ 125万
• 依托单位: Harvard University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-08-01 至 2011-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0555508&HistoricalAwards=false
• 关键词: Electron; Magnetic; Moment; Fine; Structure

This project represents a continuation of a long series of experiments that pose ever-increasingly more stringent tests of fundamental quantities and symmetries, including:1. the electron magnetic moment (often called its g value)2. the fine structure constant alpha3. most stringent test of CPT (charge-parity-time) invariance with leptons4. the ratio of the masses of the proton and electron5. the proton and antiproton magnetic momentsTechnological spinoffs of this research have been incorporated into ion cyclotron resonance spectroscopy and magnetic resonance imaging, and the improvement of promising new detectors continues, demonstrating broader applicability. A better value of alpha is crucial to determining a number of the set of fundamental constants that are needed by a technological society. Quantum electrodynamics (QED) incorporates alpha into its description of the interaction of matter and light. It is the prototype quantum field theory, serving as the model which theoretical efforts to describe strong interactions and gravity seek to emulate. An outstanding achievement of QED is the predicted relationship between the electron magnetic moment g and alpha, which allows alpha to be determined by measuring g, Given the success of calculating the parameters describing this relationship, QED theory now contributes 43 times less uncertainty to g than do previous measurements. A sufficiently improved measurement of g will thus determine alpha 43 time more accurately. An independent measurement of alpha, along with the measurement of g, will test QED to an unprecedented level of accuracy the most precise comparison of any theory and experiment. The experimental precision, with the theoretical accuracy expected in calculations underway, should allow distinguishing between inconsistent values of alpha measured from the quantum Hall effect, the ac Josephson effect, and from a neutron measurement. An iodine clock and optical comb developed for this work, technologies of much broader applicability for communications, will make possible absolute frequency measurements and more accurate measurements of frequency intervals.

该项目代表了一系列实验的延续，这些实验构成了对基本数量和对称性的更严格测试，包括：1。电子磁矩（通常称为其G值）2。精细结构常数alpha3。 leptons4的CPT（充电时间）不变性的最严格测试。质子和电子5的质量之比。这项研究的质子和抗磁磁矩技术衍生物已纳入离子回旋共振光谱和磁共振成像中，并且有希望的新探测器的改善仍在继续，显示出更广泛的适用性。 α的更高价值对于确定技术社会所需的一组基本常数至关重要。量子电动力学（QED）将alpha纳入对物质与光的相互作用的描述中。它是原型量子场理论，它是描述强烈相互作用和重力试图模仿的理论努力的模型。 QED的杰出成就是电子磁矩G和Alpha之间的预测关系，鉴于计算描述这种关系的参数的成功，QED理论现在，QED理论对G的不确定性少于先前的测量，因此可以通过测量G来确定alpha。因此，对G的测量值得到足够的改进将更准确地确定α43时间。对Alpha的独立测量以及G的测量，将测试QED至前所未有的准确性水平，即对任何理论和实验的最精确比较。 实验精度具有预期在计算中的理论准确性，应允许区分从量子霍尔效应，AC Josephson效应和中子测量值测得的α的不一致值。 为这项工作开发的碘时钟和光学梳，具有更广泛适用于通信的技术，将使可能的绝对频率测量和更准确的频率间隔测量。