Detailed analysis of arbitrary measurement devices

任意测量设备的详细分析

• 批准号: 2742333
• 金额: --
• 依托单位: University of Bristol
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2742333
• 关键词: Detailed; analysis; arbitrary; measurement; devices

Measurement devices are often assumed to be perfect and are described using a projection operator, however more generally a measurement device is not ideal and is described by a positive operator valued measure (POVM). In the non-ideal case the measurement result is sampled from a probability distribution which is not consistent with the probability distribution of the state measured in the ideal case. For example, there is a non-zero probability when measuring a single qubit our measurement device may declare the qubit is in the 1 state when it is in fact in the 0 state. In [1] it was shown that given an arbitrary measurement device it is possible to approximate an ideal measurement using ancillary qubits and multiple copies of the arbitrary measurement. We can do this by applying a unitary gate to the state we want to measure and the ancillary qubits then measuring all of the qubits using our arbitrary measurement device. A protocol assigns all the possible outcomes to a result of either 0 or 1. Both the initial unitary and the outcome assignment protocol can be optimised to approximate an ideal measurement device. This proposal centres around numerous extensions of [1], on the general topic of measurement simulation, to turn this into a mature area of research. This builds upon the research started as part of Project B.

测量设备通常被认为是完美的，并使用投影算子来描述，然而更普遍的是，测量设备并不理想，并由正算子值测量（POVM）来描述。在非理想情况下，测量结果从与理想情况下测量状态的概率分布不一致的概率分布中采样。例如，在测量单个量子位时，我们的测量设备可能会声明量子位处于1状态，而实际上它处于0状态，这是非零概率的。在[1]中，证明了给定任意测量设备，可以使用辅助量子位和任意测量的多个副本来近似理想测量。我们可以通过在我们想要测量的状态和辅助量子位上应用一个统一门，然后使用我们的任意测量设备测量所有量子位来做到这一点。协议将所有可能的结果赋值为0或1。初始单位和结果分配方案都可以优化以近似理想的测量装置。本提案围绕[1]的众多扩展，围绕测量模拟的一般主题，将其转变为一个成熟的研究领域。这建立在作为项目B的一部分开始的研究的基础上。