论文标题
用于状态制备和统一操作员合成的量子电路的数值分析
Numerical analysis of quantum circuits for state preparation and unitary operator synthesis
论文作者
论文摘要
我们执行最佳控制理论计算，以确定对量子态制备进行量子态制备和统一操作员合成所需的最小数量的两分之二cnot门的数量。通过考虑所有可能的门配置，我们确定最大可实现的保真度是量子电路大小的函数。此信息使我们能够确定特定目标操作所需的最小电路大小，并列举不同的门配置，以完美实现该操作。我们发现，即使在最小门数下，也有大量配置都产生所需的结果。我们还表明，如果我们使用多数纠缠的门而不是两分点cnot门，则可以减少纠缠门的数量，因为人们可能会根据参数计数计算所期望的那样。除了治疗任意目标状态或单一操作员的一般情况外，我们还将数值方法应用于合成多Qubit Toffoli Gate的特殊情况。这种方法可用于调查任何其他特定的少量任务，并洞悉文献中不同界限的紧密性。
We perform optimal-control-theory calculations to determine the minimum number of two-qubit CNOT gates needed to perform quantum state preparation and unitary operator synthesis for few-qubit systems. By considering all possible gate configurations, we determine the maximum achievable fidelity as a function of quantum circuit size. This information allows us to identify the minimum circuit size needed for a specific target operation and enumerate the different gate configurations that allow a perfect implementation of the operation. We find that there are a large number of configurations that all produce the desired result, even at the minimum number of gates. We also show that the number of entangling gates can be reduced if we use multi-qubit entangling gates instead of two-qubit CNOT gates, as one might expect based on parameter counting calculations. In addition to treating the general case of arbitrary target states or unitary operators, we apply the numerical approach to the special case of synthesizing the multi-qubit Toffoli gate. This approach can be used to investigate any other specific few-qubit task and provides insight into the tightness of different bounds in the literature.
