圆形里德堡原子内部的离子时钟量子比特
An ionic clock qubit inside a circular Rydberg atom
AI总结：
该研究构建了双离子-里德堡系统，利用同一碱土原子的两个电子编码两个量子比特，实现了相干耦合与类莫尔默-瑟伦森门操作，为量子模拟和计量学提供了新途径。
AI中文摘要：
被光镊捕获并激发至里德堡态的中性原子，与被囚禁的离子一同，是量子模拟和量子计算领域最先进的平台之一。当前实验常依赖相邻光阱中的额外原子，编码辅助量子比特以实现局域操控与读出。本文展示了一种双离子-里德堡系统，该系统包含两个编码于同一碱土原子的两个可单独控制的电子上的量子比特：第一个是微波量子比特，编码于一对圆形里德堡态；第二个是光学量子比特，编码于该里德堡原子离子实的窄四极跃迁上。我们实现了光学量子比特的相干操控，在动态去耦下获得了数百微秒的相干时间。此外，我们通过静电四极相互作用，在里德堡电子与离子实的大间距间实现了两个电子的相干耦合，并绘制了其角可调性。最后，我们演示了一种类似莫尔默-瑟伦森门的两量子比特操作，该操作通过四极耦合驱动，使两个量子比特演化至纠缠态。我们的工作为利用一对具有可调耦合的可单独控制的电子量子比特，开辟了通往量子模拟和量子计量学的途径。
英文摘要：
Neutral atoms trapped in optical tweezers and excited to Rydberg states, together with trapped ions, are among the most advanced platforms for quantum simulation and quantum computing. Current experiments often rely on additional atoms in neighboring traps to encode ancilla qubits for local manipulation and readout. Here, we demonstrate a dual ion-Rydberg system comprising two qubits encoded in two individually controlled electrons of the same alkaline-earth atom. The first, a microwave qubit, is encoded in a pair of circular Rydberg states, while the second, an optical qubit, is encoded on a narrow quadrupole transition of the Rydberg atom's ionic core. We demonstrate coherent control of the optical qubit and achieve coherence times of several hundred microseconds under dynamical decoupling. Furthermore, we realize coherent coupling between the two electrons via electrostatic quadrupole interactions over the large separation between the Rydberg electron and the ionic core, and map out its angular tunability. Finally, we demonstrate a two-qubit operation, reminiscent of a Mølmer-Sørensen gate, that evolves through an entangled state of the two qubits driven by the quadrupole coupling. Our work opens a pathway to exploit a pair of individually controlled electronic qubits with tunable coupling for quantum simulation and quantum metrology.
