Department of Quantum Science and Technology, Research School of Physics, The Australian National University, Canberra, ACT 2601, Australia.
Centre for Quantum and Optical Science, Swinburne University of Technology, Melbourne, VIC 3122, Australia.
Science. 2022 Apr 8;376(6589):199-203. doi: 10.1126/science.abk2502. Epub 2022 Apr 7.
Despite quantum electrodynamics (QED) being one of the most stringently tested theories underpinning modern physics, recent precision atomic spectroscopy measurements have uncovered several small discrepancies between experiment and theory. One particularly powerful experimental observable that tests QED independently of traditional energy level measurements is the "tune-out" frequency, where the dynamic polarizability vanishes and the atom does not interact with applied laser light. In this work, we measure the tune-out frequency for the 2 state of helium between transitions to the 2 and 3 manifolds and compare it with new theoretical QED calculations. The experimentally determined value of 725,736,700(260) megahertz differs from theory [725,736,252(9) megahertz] by 1.7 times the measurement uncertainty and resolves both the QED contributions and retardation corrections.
尽管量子电动力学（QED）是现代物理学中经过最严格测试的理论之一，但最近的高精度原子光谱测量结果表明，实验和理论之间存在一些小的差异。一个特别强大的实验可观测量，它可以独立于传统的能级测量来检验 QED，就是“调谐出”频率，在这个频率下，动态极化率为零，原子与外加激光光不相互作用。在这项工作中，我们测量了氦的 2 态在跃迁到 2 和 3 能级之间的调谐出频率，并将其与新的理论 QED 计算进行了比较。实验确定的值为 725,736,700(260)兆赫，与理论值[725,736,252(9)兆赫]相差 1.7 倍的测量不确定度，解决了 QED 贡献和延迟修正两个问题。
