论文标题
最佳的单个Qubit门的最佳带限制噪声过滤
Optimally Band-Limited Noise Filtering for Single Qubit Gates
论文作者
论文摘要
我们引入了一种量子控制协议,该协议可产生优化的平滑,可实现的控制序列,以应对单个Qubit系统的时间相关噪声。对照ANSATZ被专门选择为离散的pr酸球体序列的功能扩展,这是一个已知的离散时间基础,可最佳地集中在时间和频率上,并且在面对实验性控制硬件约束时非常有吸引力。我们利用过滤器功能形式主义将控制问题转换为滤波器设计问题,并证明可以仔细量身定制量子系统的频率响应,以避免噪声过程的最相关的动力学贡献。使用梯度上升,我们获得了优化的滤波器功能并利用它们,以阐明有关滤波器功能设计,控制带宽和噪声特征之间关系的重要细节。特别是,我们确定了最佳噪声抑制的模式,进而确定最佳控制带宽直接与噪声功率较大的频段大小成正比。除了提供过滤器设计的指导原理外,我们的方法还可以开发控制能够在各种复杂的噪声环境中同时产生强大的噪声过滤和高保真单量子逻辑操作。
We introduce a quantum control protocol that produces smooth, experimentally implementable control sequences optimized to combat temporally correlated noise for single qubit systems. The control ansatz is specifically chosen to be a functional expansion of discrete prolate spheroidal sequences, a discrete time basis known to be optimally concentrated in time and frequency, and quite attractive when faced with experimental control hardware constraints. We leverage the filter function formalism to transform the control problem into a filter design problem, and show that the frequency response of a quantum system can be carefully tailored to avoid the most relevant dynamical contributions of noise processes. Using gradient ascent, we obtain optimized filter functions and exploit them to elucidate important details about the relationship between filter function design, control bandwidth, and noise characteristics. In particular, we identify regimes of optimal noise suppression and in turn, optimal control bandwidth directly proportional to the size of the frequency bands where the noise power is large. In addition to providing guiding principles for filter design, our approach enables the development of controls that simultaneously yield robust noise filtering and high fidelity single qubit logic operations in a wide variety of complex noise environments.