工业多元时序数据质量评估方法

现有的数据质量评估(DQA)方法通常只从特定数据质量维度(DQD)的基本概念分析,忽略了能够反映数据质量(DQ)关键信息的细粒度的子维度对评估结果的影响。针对上述问题,提出一种工业多元时序数据质量评估(IMTSDQA)方法。首先,对于待评估的DQD,如完整性、规范性、一致性、唯一性和准确性等进行细粒度划分,考虑同一DQD内或不同DQD间各子维度的相关性以确定这些子维度的度量;其次,对完整性的属性完整性、记录完整性、数值完整性,规范性的类型规范性、精度规范性,一致性的顺序一致性、逻辑一致性,唯一性的属性唯一性、记录唯一性,准确性的范围准确性、数值准确性等子维度进行权重分配,进而充分挖掘DQD的深层次信息,从而获得反映DQ详情的评估结果。实验结果表明,与现有的基于框架定性分析、依据DQD基本定义构建模型的方法相比,IMTSDQA能更详细、更全面地评估DQ,且不同DQD的评估结果更能客观准确地反映DQ问题。

Quantum speed limit of the double quantum dot in pure dephasing environment under measurement

The quantum speed limit(QSL)of the double quantum dot(DQD)system has been theoretically investigated by adopting the detection of the quantum point contact(QPC)in the pure dephasing environment.The Mandelstam–Tamm(MT)type of the QSL bound which is based on the trace distance has been extended to the DQD system for calculating the shortest evolving time.The increase of decoherence rate can weaken the capacity for potential speedup(CPS)and delay the evolving process due to the frequently measurement localizing the electron in the DQD system.The system needs longer time to evolve to the target state as the enhancement of dephasing rate,because the strong interaction between pure dephasing environment and the DQD system could vary the oscillation of the electron.Increasing the dephasing rate can sharp the QSL bound,but the decoherence rate would weaken the former effect and vice versa.Moreover,the CPS would be raised by increasing the energy displacement,while the enhancement of the coupling strength between two quantum dots can diminish it.It is interesting that there has an inflection point,when the coupling strength is less than the value of the point,the increasing effect of the CPS from the energy displacement is dominant,otherwise the decreasing tendency of the CPS is determined by the coupling strength and suppress the action of the energy displacement if the coupling strength is greater than the point.Our results provide theoretical reference for studying the QSL time in a semiconductor device affected by numerous factors.

并联双量子点体系中的RKKY相互作用及局域磁矩

借助数值重整化群方法研究了并联双量子点体系中,在位库伦排斥作用及温度对体系局域态密度及磁矩的影响。计算表明:态密度中观察到的RKKY相互作用与在位库伦作用成反比关系;随着温度的变化,局域磁矩依次经历自由轨道区间、局域磁矩区间、自旋三重态区间以及Kondo屏蔽区间。计算结果和微扰理论的结果是吻合的。相关结论可以用来描述半导体量子点器件、磁性杂质、磁性分子结及相关团簇吸附问题的强关联效应。