Raman sideband cooling of molecules in an optical tweezer array
Raman sideband cooling of molecules in an optical tweezer array
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DOI：
10.1038/s41567-023-02346-3
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发表时间：
2023-06
期刊：
影响因子：
19.6
通讯作者：
Yu Lu;Samuel J. Li;Connor M. Holland;L. Cheuk
中科院分区：
文献类型：
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作者：
Yu Lu;Samuel J. Li;Connor M. Holland;L. Cheuk
由于其丰富的内部结构和相互作用，超冷分子已被提出作为量子科学和精密测量的候选平台。直接激光冷却有望成为一种快速有效的方法，使分子达到超冷温度。然而，对于被捕获的分子，激光冷却到量子运动基态仍然是一个突出的挑战。一种能够达到运动基态的技术是拉曼边带冷却，首先在被捕获的离子和原子中得到证明。在这里，我们展示了被困在光镊阵列中的CaF分子的拉曼边带冷却。我们的方案不依赖于高磁场，并保持分子内部状态的纯度。我们测量了一个高基态分数，并获得了每个粒子的低运动熵。我们获得的低温可以实现更长的相干时间和更高保真度的分子量子比特门，这是量子信息处理和量子模拟所需要的。随着进一步的改进，拉曼边带冷却也将为大分子样品的量子简并提供一条途径，这可以扩展到多原子分子物种。
Ultracold molecules have been proposed as a candidate platform for quantum science and precision measurement because of their rich internal structures and interactions. Direct laser-cooling promises to be a rapid and efficient way to bring molecules to ultracold temperatures. However, for trapped molecules, laser-cooling to the quantum motional ground state remains an outstanding challenge. A technique capable of reaching the motional ground state is Raman sideband cooling, first demonstrated in trapped ions and atoms. Here we demonstrate Raman sideband cooling of CaF molecules trapped in an optical tweezer array. Our protocol does not rely on high magnetic fields and preserves the purity of molecular internal states. We measure a high ground-state fraction and achieve low motional entropy per particle. The low temperatures we obtain could enable longer coherence times and higher-fidelity molecular qubit gates, desirable for quantum information processing and quantum simulation. With further improvements, Raman sideband cooling will also provide a route to quantum degeneracy of large molecular samples, which could be extendable to polyatomic molecular species.