论文标题
通过三分之二图在相测量中实现Heisenberg限制
Achieving Heisenberg limit in the phase measurement through three-qubit graph states
论文作者
论文摘要
我们研究了平均量子Fisher信息（RMQFI）的倒数，对于一般的三个Qubit状态，具有图形和超图状态为特殊情况，用于识别以$χ^2 <1 $为特征的真正的多方纠缠。我们证明，最对称的图状态和GHz状态具有最低的RMQFI值，导致最高统计速度，表明这两种状态都达到了相位灵敏度的Heisenberg限制。与GHz状态不同，图形状态具有相同的RMQFI值，用于通过不同的参数（由HyperGraph State共享的属性）进行测量。三个Qubit图和超图状态可以违反贝尔的不平等为$ f_q> n $。 GHz状态和最对称的图形状态都具有等于3和最大QFI值的最高并发状态。
We study the reciprocal of the mean quantum Fisher information (RMQFI), $χ^2$ for general three qubit states, having graph and hypergraph states as special cases, for identifying genuine multi party entanglement characterized by $χ^2 <1$. We demonstrate that the most symmetric graph state and the GHZ state have the lowest RMQFI values leading to the highest statistical speed showing that both these states attain the Heisenberg limit in phase sensitivity. Unlike the GHZ state, graph states have the same RMQFI values for measurement through different parameters, a property shared by the hypergraph states. Three qubit graph and hypergraph states can violate Bell's inequality as $F_Q > N$. Both the GHZ state and the most symmetric graph state have the highest concurrence equalling 3 and the maximum QFI values.
