PM: Precision Low-Energy Quantum Electroynamic Theory and Fundamental Processes

从一般的角度来看，这个研究项目涉及影响束缚原子系统光谱的微小但重要的效应，在束缚原子系统中，两个基本粒子在量子轨迹上相互绕圈。当人们将量子理论与相对论结合起来，并将场量子化加入其中时，就会产生一个复杂的理论，称为量子电动力学。这个理论已经被实验验证了几十年，并且得到了证实。最近，除了量子电动力学之外，一些有趣的新效应可能以所谓的X17粒子的形式被发现，这种粒子只与那些被广泛接受的粒子物理学标准模型所描述的粒子弱耦合。由假想的新粒子介导的效应，在束缚系统的光谱中可见，应该用高精度的计算来探索。这只是许多基本量子场理论效应中的一个，这些效应将在该基金的背景下进行研究。其他效应与原子表面相互作用的温度依赖性有关，所谓的热场理论的效应可能已经在实验中看到，并且可以第一次与理论进行比较。这项工作将辅以投机性和高风险的工作，以克服几十年来确立标准的理论方法的预测局限性。该项目包括研究原子中量子电动力学效应的高阶修正和束缚电子g因子的高阶修正，以及研究重束缚系统中的高阶量子电动力学修正，其中轨道粒子比电子重。由于质子半径谜题以及所谓的ATOMKI异常（与标准模型中可能的暗光子添加有关），后一个系统引起了人们的兴趣。由假想的X17粒子引起的效应在重束缚系统中比轻束缚系统中显著增强。补充量子电动力学计算，并在高精度上探索量子场理论，将研究基本的温度依赖动态卡西米尔过程，涉及原子-表面相互作用，并将探索计算大环阶费曼图的新技术，可以想象，克服当前摄动理论的预测极限。在奖励期间，应完成一本770页的量子电动力学书籍，作为社区的参考。上述子项目对于低能域基本量子场论的普遍理解具有重要意义，其意义和影响超出了原有的研究领域。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Seen from a general perspective, this research project deals with tiny, but important, effects which influence the spectrum of bound atomic systems, where two fundamental elementary particles circle around each other on quantum trajectories. When one combines quantum theory with relativity and adds the field quantization into the mix, then a complicated theory results, which is called quantum electrodynamics. This theory has been tested against experiment for decades, and confirmed. Recently, some interesting new effects, beyond quantum electrodynamics, may have been seen in the form of a so-called X17 particle which only couples weakly to those particles that are described by the widely-accepted Standard Model of particle physics. Effects mediated by the hypothetical new particle, visible in the spectrum of bound systems, shall be explored with high-precision calculations. This is but one of many fundamental quantum-field theoretical effects which will be studied in the context of the grant. Other effects pertain to the temperature-dependence of atom-surface interactions where the effects of so-called thermal field theory may have been seen in an experiment, and could be compared to theory for the first time. The work will be supplemented by speculative and high-risk work on overcoming the predictive limits of theoretical approaches that have set the standard for decades.The project includes the study of higher-order corrections due to quantum electrodynamic effects in atoms and higher-order corrections to the bound-electron g-factor, and the investigation of higher-order quantum electrodynamic corrections in heavy bound systems, where the orbiting particle is heavier than the electron. The latter system is of interest due to the proton radius puzzle as well as the so-called ATOMKI anomaly (which pertains to conceivable dark-photon additions to the Standard Model). The effects due to the hypothetical X17 particle are drastically enhanced in heavy as opposed to light bound systems. Complementing the quantum electrodynamic calculations, and exploring quantum field theory at high precision, fundamental temperature-dependent dynamic Casimir processes will be investigated, pertaining to atom-surface interactions, and novel techniques will be explored for the calculation of large-loop-order Feynman diagrams, conceivably overcoming current predictive limits of perturbation theory. A 770-page book on quantum electrodynamics should be completed during the award period, serving as a reference for the community. All of the above mentioned subprojects have broader significance and impacts beyond the original field of study, because of their importance for the general understanding of fundamental quantum field theory in the low-energy domain.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.