论文标题
由共享可调节耦合器介导的超导量子位的受控控制式闸门
Controlled-Controlled-Phase Gates for Superconducting Qubits Mediated by a Shared Tunable Coupler
论文作者
论文摘要
嘈杂的中等规模量子计算设备的应用依赖于许多量子位的有效纠缠来达到潜在的量子优势。尽管纠缠通常是使用两倍的门产生的，但直接控制强多量相互作用可以提高过程的效率。在这里，我们研究了通过单个通量可调节耦合器耦合的三个超导型transmon型量子的系统。通过绝热通量脉冲来调整耦合器的频率，使我们能够控制Qubits之间的条件能量移动并直接实现多量相互作用。为了准确调整所得的受控相对相位，我们描述了涉及重新聚焦脉冲和可调相互作用时间的门协议。这可以实现完整的成对受控相（CPHASE）和受控控制的相（CCPHASE）门的家族。数值模拟使用当前可实现的系统参数和反谐波速率导致延迟约为99％，栅极时间低于300 ns。
Applications for noisy intermediate-scale quantum computing devices rely on the efficient entanglement of many qubits to reach a potential quantum advantage. Although entanglement is typically generated using two-qubit gates, direct control of strong multi-qubit interactions can improve the efficiency of the process. Here, we investigate a system of three superconducting transmon-type qubits coupled via a single flux-tunable coupler. Tuning the frequency of the coupler by adiabatic flux pulses enables us to control the conditional energy shifts between the qubits and directly realize multi-qubit interactions. To accurately adjust the resulting controlled relative phases, we describe a gate protocol involving refocusing pulses and adjustable interaction times. This enables the implementation of the full family of pairwise controlled-phase (CPHASE) and controlled-controlled-phase (CCPHASE) gates. Numerical simulations result in fidelities around 99 % and gate times below 300 ns using currently achievable system parameters and decoherence rates.
