Wang Ye, Crain Stephen, Fang Chao, Zhang Bichen, Huang Shilin, Liang Qiyao, Leung Pak Hong, Brown Kenneth R, Kim Jungsang
Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708, USA.
Department of Physics, Duke University, Durham, North Carolina 27708, USA.
Phys Rev Lett. 2020 Oct 9;125(15):150505. doi: 10.1103/PhysRevLett.125.150505.
In a large scale trapped atomic ion quantum computer, high-fidelity two-qubit gates need to be extended over all qubits with individual control. We realize and characterize high-fidelity two-qubit gates in a system with up to four ions using radial modes. The ions are individually addressed by two tightly focused beams steered using microelectromechanical system mirrors. We deduce a gate fidelity of 99.49(7)% in a two-ion chain and 99.30(6)% in a four-ion chain by applying a sequence of up to 21 two-qubit gates and measuring the final state fidelity. We characterize the residual errors and discuss methods to further improve the gate fidelity towards values that are compatible with fault-tolerant quantum computation.
在大规模囚禁原子离子量子计算机中，高保真两比特门需要在所有可单独控制的量子比特上扩展。我们利用径向模式在一个包含多达四个离子的系统中实现并表征了高保真两比特门。这些离子通过使用微机电系统镜子控制的两束紧密聚焦光束进行单独寻址。通过应用多达21个两比特门的序列并测量最终状态保真度，我们推导出在双离子链中的门保真度为99.49(7)%，在四离子链中的门保真度为99.30(6)%。我们表征了残余误差，并讨论了进一步提高门保真度以达到与容错量子计算兼容的值的方法。
