RUI: Calculation of Higher Order Corrections to Positronium Energy Levels

RUI：正电子能级高阶修正的计算

• 批准号: 1707489
• 负责人: Gregory Adkins
• 金额: $ 18万
• 依托单位: Franklin and Marshall College
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-08-01 至 2021-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1707489&HistoricalAwards=false
• 关键词: RUI; Calculation; Higher; Order; Corrections; RUI; Calculation; Higher; Order; Corrections

Positronium is a bound state of an electron and its antiparticle, a positron. As such, it forms an "exotic atom," similar in many ways to the 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 in this system. Consequently, positronium is an ideal system for testing the limits of electromagnetic bound state physics. The activities involved in calculating the positronium energy levels will be of great educational value to the undergraduate students involved as collaborators in this 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 one MHz, and experiments are presently being developed to significantly reduce some of these uncertainties. The 2S-1S transition is of particular interest because it has the smallest natural linewidth and thus the greatest potential for improvement. The ground state hyperfine splitting is of interest because the most precise experimental results are not in accord with current theory. These transition energies and more will be calculated to a new 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.

正电子是电子及其反粒子的结合状态，一个正电子。 因此，它形成了一种“异国原子”，在许多方面与传统的简单原子（如氢和氦气）相似，但由于其独特的组成和趋于歼灭的趋势，以高增强光子的形式转化为纯电磁能。 高精度实验可以使用正电子的许多特性，例如能量水平和寿命。 在理论上，也可以使用界限量子电动力学（QED）的方法在理论上计算出正电子性能，因为在该系统中，强和弱相互作用效应可以忽略不计。 因此，正电子是测试电磁结合状态物理学极限的理想系统。 计算正电子能量水平的活动对这项工作的合作者的本科生将具有巨大的教育价值。 与本科生通常相比，学生将学习理论方法和计算技术更先进的方法。 他们将通过进行研究，在专业会议上呈现结果，并在研究期刊上发表其工作来获得宝贵的经验。低洼状态的positronium能量水平（n = 1和n = 2）已通过大约一个MHz的不确定性进行了测量，并且实验已开发出来，以显着降低了这些未经遗嘱的剂量。 2S-1S的转变特别令人感兴趣，因为它具有最小的自然线宽，因此最大的改进潜力。 基态超细分裂引起了人们的关注，因为最精确的实验结果与当前理论不符。 这些过渡能和更多的能量将被计算为新的精度水平。 该计算将基于低能量有效的量子场理论NRQED（非相关性QED），该理论为研究非相关原子的研究提供了自然有效的框架。