标题： 二次动态解耦与非均匀误差抑制 显示英文标题

标题： Quadratic Dynamical Decoupling with Non-Uniform Error Suppression

摘要： 我们数值分析了近最优二次动态解耦（QDD）单量子比特退相干误差抑制方法的性能 [J. West 等, Phys. Rev. Lett. 104, 130501 (2010)]。QDD 序列由嵌套两个最优 Uhrig 动态解耦序列组成，分别用于两个正交轴，分别包含 N1 和 N2 个脉冲。通过改变这些数字，我们直接研究 QDD 的退相干抑制特性，通过隔离系统-环境相互作用哈密顿量中每个系统基算符相关的误差。每个单独的误差与 Dyson 级数的最低阶成比例，因此立即得出退相干抑制的阶数。我们表明 QDD 的误差抑制特性取决于 N1 和 N2 的奇偶性，当 N1=N2 时，对于一般的单量子比特相互作用可以实现近最优性能。 显示英文摘要

摘要： We analyze numerically the performance of the near-optimal quadratic dynamical decoupling (QDD) single-qubit decoherence errors suppression method [J. West et al., Phys. Rev. Lett. 104, 130501 (2010)]. The QDD sequence is formed by nesting two optimal Uhrig dynamical decoupling sequences for two orthogonal axes, comprising N1 and N2 pulses, respectively. Varying these numbers, we study the decoherence suppression properties of QDD directly by isolating the errors associated with each system basis operator present in the system-bath interaction Hamiltonian. Each individual error scales with the lowest order of the Dyson series, therefore immediately yielding the order of decoherence suppression. We show that the error suppression properties of QDD are dependent upon the parities of N1 and N2, and near-optimal performance is achieved for general single-qubit interactions when N1=N2.