Department of Physics, QSO-Centre for Quantum Science, and Dodd-Walls Centre for Photonic and Quantum Technologies, University of Otago, 730 Cumberland Street, Dunedin 9016, New Zealand.
Joint Quantum Institute and Centre for Quantum Information and Computer Science, National Institute of Standards and Technology and University of Maryland, Gaithersburg, MD, 20899, USA.
Nat Commun. 2018 Nov 20;9(1):4895. doi: 10.1038/s41467-018-07375-8.
Quantum mechanical scattering resonances for colliding particles occur when a continuum scattering state couples to a discrete bound state between them. The coupling also causes the bound state to interact with itself via the continuum and leads to a shift in the bound state energy, but, lacking knowledge of the bare bound state energy, measuring this self-energy via the resonance position has remained elusive. Here, we report on the direct observation of self-interaction by using a nano-eV atom collider to track the position of a magnetically-tunable Feshbach resonance through a parameter space spanned by energy and magnetic field. Our system of potassium and rubidium atoms displays a strongly non-monotonic resonance trajectory with an exceptionally large self-interaction energy arising from an interplay between the Feshbach bound state and a different, virtual bound state at a fixed energy near threshold.
当连续散射态与它们之间的离散束缚态耦合时，发生碰撞粒子的量子力学散射共振。这种耦合还导致束缚态通过连续态与自身相互作用，并导致束缚态能量发生移动，但是，由于缺乏对裸束缚态能量的了解，通过共振位置测量这种自能一直难以实现。在这里，我们报告了通过使用纳电子伏特原子对撞机直接观察自相互作用，通过跨越能量和磁场的参数空间来跟踪磁可调费希巴赫共振位置。我们的钾和铷原子系统显示出强烈的非单调共振轨迹，由于费希巴赫束缚态和固定阈值附近的不同虚拟束缚态之间的相互作用，自相互作用能量异常大。
