RUI: Calculation of Higher Order Corrections to Positronium Energy Levels

RUI：正电子能级高阶修正的计算

基本信息

批准号：
2011762
负责人：
Gregory Adkins
金额：
$ 15万
依托单位：
Franklin and Marshall College
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2020
资助国家：
美国
起止时间：
2020-08-15 至 2023-07-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2011762&HistoricalAwards=false
关键词：
RUI Calculation Higher Order Corrections

项目摘要

Positronium is the bound system consisting of the electron and its antiparticle, the positron. As such, it forms an “exotic atom”, similar in many ways to traditional simple atoms such as hydrogen and helium, but different because of its unique composition and because of its tendency to annihilate, transforming into pure electromagnetic energy in the form of high-energy photons. Many properties of positronium, such as energy levels and lifetimes, are accessible to high-precision experiments. Positronium properties can also be calculated theoretically to high precision using the methods of bound-state Quantum Electrodynamics (QED) because strong and weak interaction effects are negligible. Consequently, positronium is an ideal system for testing the limits of QED bound state physics and for exploring the consequences of agreement or disagreement between theory and experiment at this high level of precision. The activities involved in calculating the positronium energy levels will be of great educational value to the undergraduate students at Franklin & Marshall College involved as collaborators in that work. The students will learn theoretical methods and techniques of calculation more advanced than those usually encountered at the undergraduate level. They will gain valuable experience by doing the research, by presenting their results at professional meetings, and by publishing their work as co-authors in research journals. Positronium energy levels of low-lying states (n=1 and n=2) have been measured with uncertainties of roughly 1 MHz, and experiments are presently being developed and performed to significantly reduce some of these uncertainties. The 1S-2S transition is of particular interest because it has the smallest natural line-width and thus the greatest potential for improvement. These transition energies and more will be calculated to a new and higher level of precision. The calculations will be based on the low-energy effective quantum field theory NRQED (Non-Relativistic QED), which provides a natural and efficient framework for the study of non-relativistic atoms such as positronium.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

正电子是由电子及其反粒子正电子组成的束缚系统，因此，它形成了一种“奇异原子”，在许多方面与氢和氦等传统简单原子相似，但由于其独特的组成和原因而有所不同。正电子素的许多特性，例如能级和寿命，都可以通过高精度实验获得。使用束缚态量子电动力学 (QED) 的计算方法理论上也可以实现高精度，因为强相互作用和弱相互作用效应可以忽略不计。正电子素是测试 QED 束缚态物理极限和探索一致性结果的理想系统计算正电子能级的活动对于作为合作者参与这项工作的富兰克林与马歇尔学院的本科生来说具有很大的教育价值。学生将学习理论方法。和技术他们将通过进行研究、在专业会议上展示他们的结果以及作为合著者在低正电子能级的研究期刊上发表他们的工作来获得宝贵的经验。卧态（n=1 和 n=2）的测量不确定度约为 1 MHz，目前正在开发和执行实验以显着降低其中一些不确定性。1S-2S 转变特别令人感兴趣，因为它具有最小的自然这些跃迁能量和更多的线宽将被计算到一个新的、更高的精度水平。计算将基于低能有效量子场论 NRQED（非相对论 QED），它为研究非相对论性原子（如正电子素）提供了一个自然而有效的框架。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。