Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA.
Department of Physics, Gordon College, Wenham, Massachusetts 01984, USA.
Phys Rev Lett. 2019 Oct 25;123(17):170503. doi: 10.1103/PhysRevLett.123.170503.
We report the implementation of universal two- and three-qubit entangling gates on neutral-atom qubits encoded in long-lived hyperfine ground states. The gates are mediated by excitation to strongly interacting Rydberg states and are implemented in parallel on several clusters of atoms in a one-dimensional array of optical tweezers. Specifically, we realize the controlled-phase gate, enacted by a novel, fast protocol involving only global coupling of two qubits to Rydberg states. We benchmark this operation by preparing Bell states with fidelity F≥95.0(2)%, and extract gate fidelity ≥97.4(3)%, averaged across five atom pairs. In addition, we report a proof-of-principle implementation of the three-qubit Toffoli gate, in which two control atoms simultaneously constrain the behavior of one target atom. These experiments demonstrate key ingredients for high-fidelity quantum information processing in a scalable neutral-atom platform.
我们报告了在编码于长寿命超精细基态中的中性原子量子比特上实现通用的双量子比特和三量子比特纠缠门。这些门是通过激发到强相互作用的里德堡态来介导的，并在一维光镊阵列中的几个原子簇上并行实现。具体来说，我们实现了受控相位门，该门由一种新的、快速协议来执行，该协议仅涉及将两个量子比特全局耦合到里德堡态。我们通过使用保真度 F≥95.0(2)％来验证此操作，并且在五个原子对中平均提取出≥97.4(3)％的门保真度。此外，我们还报告了三量子比特 Toffoli 门的原理证明实现，其中两个控制原子同时约束一个目标原子的行为。这些实验证明了在可扩展的中性原子平台中进行高保真量子信息处理的关键要素。
