We analytically evaluate the efficiency of continuous dynamical decoupling (CDD) to curb decoherence in generic qubit setups where diverse sources of noise can be present. Previous theoretical approaches to CDD have mainly focused on its potential to cope with longitudinal fluctuations. Here, the basic scenario tackled with CDD is generalized. Apart from dealing with pure dephasing induced by diagonal noise, we consider the impact of transverse fluctuations, usually present in the practical arrangements. In particular, the implications of anisotropic noisy inputs are studied. Additionally, we analyze the role of the fluctuations in the dressing of the qubit by the CDD field of control: since the driving field is usually switched on through linear ramps of its characteristic parameters, the associated dressing of the original states can be described in terms of noisy Landau-Zener transitions. In our approach, based on a sequence of unitary transformations, the noise entering the system is cast into effective stochastic terms whose spectral characteristics are dependent on the driving parameters. This description allows the design of strategies to mitigate the impact of the fluctuations using controlled changes in the effective-noise properties. Significant robustness of CDD against the generalization of the basic scenario can be achieved through an appropriate choice of the parameters of control.

翻译：我们解析评估了连续动态去耦（CDD）在抑制通用量子比特系统中由多种噪声源引发的退相干方面的效率。以往关于CDD的理论研究主要关注其应对纵向涨落的潜力。本文将CDD处理的基本场景进行了推广。除了处理对角噪声诱导的纯退相位外，我们还考虑了实际装置中通常存在的横向涨落的影响。特别地，研究了各向异性噪声输入的效应。此外，我们分析了CDD控制场对量子比特缀饰过程中涨落的作用：由于驱动场通常通过其特征参数的线性斜坡开启，原始态的关联缀饰可用含噪的Landau-Zener跃迁描述。基于一系列幺正变换的方法中，进入系统的噪声被转化为有效随机项，其谱特性取决于驱动参数。这一描述允许通过可控改变有效噪声特性来设计缓解涨落影响的策略。通过合理选择控制参数，CDD在基本场景推广下可实现显著的鲁棒性。