论文标题
双Qubit Bloch球
Two-Qubit Bloch Sphere
论文作者
论文摘要
三个单位球被用来表示两数数分的纯态。这三个球体被命名为基本球体，纠缠球和纤维球。基本球和纠缠球表示基本值的减少密度矩阵和非本地纠缠度量，同时同时，而纤维球则通过局部单量子单位操作下的简单旋转来代表纤维值。但是，在纠缠的两分状态下，纤维球没有有关纤维量子量降低密度基质的信息。当双分裂状态变得可分离时，碱基和纤维球无缝地成为每个量子的单Qubit Bloch球体。由于可以选择这三个球体的两个替代集，因此可以选择这三个球体的两个替代集，其中每个集合完全代表了两部分纯状态，并且每个集合都有其基本值的还原密度矩阵的信息。将此模型与代表两个量子位的密度矩阵降低密度矩阵的两个Bloch球进行比较，每个Bloch球对应于我们模型中的两个单位球体，即碱基和纠缠球。并发互互表示互补性通过单个角度明确显示在纠缠球上。
Three unit spheres were used to represent the two-qubit pure states. The three spheres are named the base sphere, entanglement sphere, and fiber sphere. The base sphere and entanglement sphere represent the reduced density matrix of the base qubit and the non-local entanglement measure, concurrence, while the fiber sphere represents the fiber qubit via a simple rotation under a local single-qubit unitary operation; however, in an entangled bipartite state, the fiber sphere has no information on the reduced density matrix of the fiber qubit. When the bipartite state becomes separable, the base and fiber spheres seamlessly become the single-qubit Bloch spheres of each qubit. Since either qubit can be chosen as the base qubit, two alternative sets of these three spheres are available, where each set fully represents the bipartite pure state, and each set has information of the reduced density matrix of its base qubit. Comparing this model to the two Bloch balls representing the reduced density matrices of the two qubits, each Bloch ball corresponds to two unit spheres in our model, namely, the base and entanglement spheres. The concurrence-coherence complementarity is explicitly shown on the entanglement sphere via a single angle.
