论文标题
在弱测量和选择后的状态区分性：统一的系统和设备透视图
State distinguishability under weak measurement and post-selection: A unified system and device perspective
论文作者
论文摘要
我们量化了经过一系列观测的量子状态的干扰，尤其是专注于弱测量，然后进行选择后，并将这些结果与投射的对应物进行比较。考虑到系统和设备的区分性，我们获得了系统状态干扰与设备指针状态的更改之间的确切权衡。我们表明，对于特定的选择后程序，可以大大降低系统与设备之间的耦合强度，而不会失去测量灵敏度，该敏感性直接转移到了系统的状态干扰。我们观察到，仅弱测量并不能提供这一优势，但仅与选择后结合使用，就发现了提高的测量灵敏度和降低的状态干扰。我们进一步表明，在现实的实验条件下，这种状态干扰很小，而确切的选择后概率大大大于忽略系统状态干扰时初始和最终状态的重叠所给出的近似值。
We quantify the disturbance of a quantum state undergoing a sequence of observations, and particularly focus on a weak measurement followed by post-selection and compare these results to the projective counterpart. Taking into account the distinguishability of both, the system and the device, we obtain the exact trade-off between the system state disturbance and the change of the device pointer state. We show that for particular post-selection procedures the coupling strength between the system and the device can be significantly reduced without loosing measurement sensitivity, which is directly transferred to a reduced state disturbance of the system. We observe that a weak measurement alone does not provide this advantage but only in combination with post-selection a significant improvement in terms of increased measurement sensitivity and reduced state disturbance is found. We further show that under realistic experimental conditions this state disturbance is small, whereas the exact post-selection probability is considerably larger than the approximate value given by the overlap of the initial and final state when neglecting the system state disturbance.
