近日，荷兰阿姆斯特丹大学的Florian Schreck及其研究团队取得一项新进展。他们揭示了具有原子束的连续腔量子电动力学。相关研究成果已于2024年12月26日在国际知名学术期刊《物理评论A》上发表。

据悉，原子与腔的耦合为研究通过共同通道介导的原子基本相互作用，提供了一个令人兴奋的领域。在腔量子电动力学（QED）和更广泛的冷原子实验中，许多应用都受到原子装载周期瞬态性质所带来的限制。为了推动这些系统达到更高水平的性能，开发连续运行方案是必不可少的。

该研究团队提出一种机器，它设计用于产生连续束流的准直原子，这些原子穿过一个光学腔。通过一个快速衰减的腔，增强了原子与光的相互作用，该腔非常适合研究原子特性占主导地位的现象。研究人员观察到了以正常模式分裂为标志的集体强耦合态的转变。

此外，研究人员还观察到二次相，其中由于原子平均速度的偏移，出现了二元的正常模式分裂。在集体强耦合态下，通过反转原子系综，研究人员测量到了连续的光增益。这项工作为研究连续集体现象（如连续超辐射激光）的阈值条件奠定了基础。

附：英文原文

Title: Continuous cavity QED with an atomic beam

Author: Francesca Famà1, Sheng Zhou1, Benedikt Heizenreder1, Mikkel Tang1,2, Shayne Bennetts1, Simon B. Jäger3, Stefan A. Schäffer1,2, and Florian Schreck1,4,*

Issue&Volume: 2024-12-26

Abstract: Atoms coupled to cavities provide an exciting playground for the study of fundamental interactions of atoms mediated through a common channel. Many of the applications of cavity QED and cold-atom experiments more broadly, suffer from limitations caused by the transient nature of an atomic loading cycle. The development of continuous operation schemes is necessary to push these systems to the next level of performance. Here we present a machine designed to produce a continuous flux of collimated atoms that traverse an optical cavity. The atom-light interaction is enhanced by a fast-decaying cavity optimal for studying phenomena where atomic properties dominate. We demonstrate the transition to a collective strong-coupling regime heralded by a normal-mode splitting. We observe a second phase with a binary normal-mode splitting born from an offset in the mean velocity of the atoms. Inverting the atomic ensemble in the collective strong-coupling regime, we measure continuous optical gain. This work sets the stage for studying threshold conditions for continuous collective phenomena, such as continuous superradiant lasing.

DOI: https://doi.org/10.1103/PhysRevA.110.063721

Source: https://journals.aps.org/pra/abstract/10.1103/PhysRevA.110.063721