Fidelity of a Rydberg-blockade quantum gate from simulated quantum process tomography
Fidelity of a Rydberg-blockade quantum gate from simulated quantum process tomography
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DOI：
10.1103/physreva.85.042310
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发表时间：
2012-01
影响因子：
2.9
通讯作者：
X. L. Zhang;A. Gill;L. Isenhower;Thomas G. Walker;M. Saffman
中科院分区：
文献类型：
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作者：
X. L. Zhang;A. Gill;L. Isenhower;Thomas G. Walker;M. Saffman
我们提出了一个详细的错误分析的里德堡封锁介导的控制非量子门两个中性原子之间的最近在物理学评论。104，010503（2010）和Phys.Rev.A82，030306（2010）。门动态的主方程的数值解，包括所有已知的技术误差源，被证明是在良好的协议与实验。门误差的主要来源进行了鉴定，并为今后的改进提出了建议。我们还提出了量子过程层析成像的数值模拟，以找到内在的保真度，忽略技术误差，里德堡封锁控制的相位门。门保真度的特点是使用轨迹重叠和轨迹距离的措施。我们表明，跟踪距离是线性敏感的有限里德伯封锁移位所产生的错误，并引入一个修改后的脉冲序列，纠正线性错误。我们的分析表明，从模拟的量子过程层析提取的本征门误差可以在0.002以下的特定状态的$^{87}$Rb或Cs原子。讨论了容错阈值计算中所用的门错误概率与工艺保真度之间的关系。
We present a detailed error analysis of a Rydberg blockade mediated controlled-NOT quantum gate between two neutral atoms as demonstrated recently in Phys. Rev. Lett. 104, 010503 (2010) and Phys. Rev. A 82, 030306 (2010). Numerical solutions of a master equation for the gate dynamics, including all known sources of technical error, are shown to be in good agreement with experiments. The primary sources of gate error are identified and suggestions given for future improvements. We also present numerical simulations of quantum process tomography to find the intrinsic fidelity, neglecting technical errors, of a Rydberg blockade controlled phase gate. The gate fidelity is characterized using trace overlap and trace distance measures. We show that the trace distance is linearly sensitive to errors arising from the finite Rydberg blockade shift and introduce a modified pulse sequence which corrects the linear errors. Our analysis shows that the intrinsic gate error extracted from simulated quantum process tomography can be under 0.002 for specific states of $^{87}$Rb or Cs atoms. The relation between the process fidelity and the gate error probability used in calculations of fault tolerance thresholds is discussed.