Nuclear spin conservation enables state-to-state control of ultracold molecular reactions
Nuclear spin conservation enables state-to-state control of ultracold molecular reactions
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DOI：
10.1038/s41557-020-00610-0
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发表时间：
2020-05
期刊：
影响因子：
21.8
通讯作者：
Ming-Guang Hu;Yu Liu;M. Nichols;Lingbang Zhu;G. Quéméner;O. Dulieu;Kang-kuen Ni
中科院分区：
文献类型：
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作者：
Ming-Guang Hu;Yu Liu;M. Nichols;Lingbang Zhu;G. Quéméner;O. Dulieu;Kang-kuen Ni
反应体系的量子态控制使得利用量子统计对潜在的相互作用势和反应速率的变化进行微观探测成为可能。然而，将这种控制扩展到反应结果的量子态仍然具有挑战性。在这里，我们通过在整个反应过程中利用核自旋守恒来实现这一目标。用共振增强多光子电离光谱研究了超冷KRb分子之间的双分子反应产物，发现该体系对反应物的核自旋具有近乎完美的记忆，表现为对产物旋转态的强烈宇称择优。我们利用这一效应通过改变初始核自旋态与外加磁场的相干叠加来改变这些乘积态的占据。通过这种方式，我们能够以量子态分辨率控制反应的输入和输出。本文所展示的技术为在状态水平上研究反应产物之间的量子纠缠和超冷反应动力学提供了可能性。
Quantum-state control of reactive systems has enabled microscopic probes of underlying interaction potentials and the alteration of reaction rates using quantum statistics. However, extending such control to the quantum states of reaction outcomes remains challenging. Here, we realize this goal by utilizing the conservation of nuclear spins throughout the reaction. Using resonance-enhanced multiphoton ionization spectroscopy to investigate the products formed in bimolecular reactions between ultracold KRb molecules we find that the system retains a near-perfect memory of the reactants’ nuclear spins, manifested as a strong parity preference for the rotational states of the products. We leverage this effect to alter the occupation of these product states by changing the coherent superposition of initial nuclear spin states with an external magnetic field. In this way, we are able to control both the inputs and outputs of a reaction with quantum-state resolution. The techniques demonstrated here open up the possibilities to study quantum entanglement between reaction products and ultracold reaction dynamics at the state-to-state level.