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，其中两个基本粒子在量子轨道上相互环绕。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粒子的形式出现，这种粒子只与那些被广泛接受的粒子物理学标准模型描述的粒子弱耦合。应通过高精度计算探索在束缚系统光谱中可见的假想新粒子所介导的效应。 这仅仅是将在资助范围内研究的许多基本量子场论效应之一。其他效应与原子-表面相互作用的温度依赖性有关，其中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。该项目还将开展一些探索性和高风险的工作，以克服几十年来一直为标准的理论方法的预测极限。该项目包括研究原子中量子电动力学效应引起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，后一个系统由于质子半径之谜以及所谓的ATOMKI异常（与标准模型中可能的暗光子增加有关）而令人感兴趣。由于假设的X17粒子的影响在重束缚系统中大大增强，而不是轻束缚系统。补充量子电动力学计算，并探索量子场论的高精度，基本的温度依赖性动态卡西米尔过程将被调查，有关原子表面相互作用，并将探索新的技术来计算大回路阶费曼图，可以想象克服当前的预测限制微扰理论。一本770页的关于量子电动力学的书应该在颁奖期间完成，作为社区的参考。以上提到的所有子项目，由于其对低能领域基本量子场论的普遍理解的重要性，具有超出原有研究领域的更广泛意义和影响。该奖项反映了NSF的法定使命，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。

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.