Ideal projective quantum measurement makes the system state collapse in one of the observable operator eigenstates |ϕα⟩ , making it a powerful tool for preparing the system in the desired pure state. Nevertheless, experimental realisations of projective measurement are not ideal. During the measurement time needed to overcome the classical noise of the apparatus, the system state is often (slightly) perturbed, which compromises the fidelity of initialisation. In this paper, we propose an analytical model to analyse the initialisation fidelity of the system performed by the single-shot readout. We derive a method to optimise parameters for the three most used cases of photon counting based readouts for NV colour centre in diamond, charge state, nuclear spin and low temperature electron spin readout. Our work is of relevance for the accurate description of initialisation fidelity of the quantum bit when the single-shot readout is used for initialisation via post-selection or real-time control.

中文翻译：

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有限拆卸单次读出的读出和初始化保真度

理想的射影量子测量使系统状态崩溃在可观察算子本征态之一 |φα⟩ ，使其成为将系统制备成所需纯净状态的强大工具。然而，投影测量的实验实现并不理想。在克服设备的经典噪声所需的测量时间内，系统状态经常（轻微）受到干扰，这会损害初始化的保真度。在本文中，我们提出了一种分析模型来分析单次读出执行的系统的初始化保真度。我们推导出一种方法来优化金刚石 NV 色心、电荷态、核自旋和低温电子自旋读出的三种最常用的基于光子计数的读出情况的参数。当单次读出用于通过后选择或实时控制进行初始化时，我们的工作与准确描述量子位的初始化保真度相关。