Hua Ming, Tao Ming-Jie, Deng Fu-Guo
Department of Physics, Applied Optics Beijing Area Major Laboratory, Beijing Normal University, Beijing 100875, China.
Sci Rep. 2015 Mar 19;5:9274. doi: 10.1038/srep09274.
Stark shift on a superconducting qubit in circuit quantum electrodynamics (QED) has been used to construct universal quantum entangling gates on superconducting resonators in previous works. It is a second-order coupling effect between the resonator and the qubit in the dispersive regime, which leads to a slow state-selective rotation on the qubit. Here, we present two proposals to construct the fast universal quantum gates on superconducting resonators in a microwave-photon quantum processor composed of multiple superconducting resonators coupled to a superconducting transmon qutrit, that is, the controlled-phase (c-phase) gate on two microwave-photon resonators and the controlled-controlled phase (cc-phase) gates on three resonators, resorting to quantum resonance operations, without any drive field. Compared with previous works, our universal quantum gates have the higher fidelities and shorter operation times in theory. The numerical simulation shows that the fidelity of our c-phase gate is 99.57% within about 38.1 ns and that of our cc-phase gate is 99.25% within about 73.3 ns.
在先前的工作中,电路量子电动力学(QED)中超导量子比特上的斯塔克位移已被用于在超导谐振器上构建通用量子纠缠门。它是色散区域中谐振器与量子比特之间的二阶耦合效应,会导致量子比特上的慢态选择性旋转。在此,我们提出两个方案,用于在由多个耦合到超导三能级磁通量子比特的超导谐振器组成的微波光子量子处理器中,借助量子共振操作,在无任何驱动场的情况下,在超导谐振器上构建快速通用量子门,即两个微波光子谐振器上的受控相位(c相位)门和三个谐振器上的受控受控相位(cc相位)门。与先前的工作相比,我们的通用量子门在理论上具有更高的保真度和更短的操作时间。数值模拟表明,我们的c相位门在约38.1纳秒内保真度为99.57%,cc相位门在约73.3纳秒内保真度为99.25%。