Quantum-information distributors: Quantum network for symmetric and asymmetric cloning in arbitrary dimension and continuous limit
Quantum-information distributors: Quantum network for symmetric and asymmetric cloning in arbitrary dimension and continuous limit
复制标题
DOI：
10.1103/physreva.63.052313
复制
发表时间：
2001-05-01
影响因子：
2.9
通讯作者：
Hillery, M
中科院分区：
文献类型：
--
作者：
Braunstein, SL;Buzek, V;Hillery, M
我们证明，对于任何希尔伯特空间维数，最佳的1->2通用量子克隆器可以从本质上相同的量子电路，即，我们找到了通用克隆机的通用设计。在无限维（包括连续变量量子系统）的情况下，通用克隆器基本上变成了经典设备。更一般地说，我们构造了一个通用的量子电路，用于在任何维度上分配量子，该量子电路在广义位移和动量踢下协变地起作用。这个协变分配器的行为由其初始状态控制。我们表明，合适的选择，这个初始状态产生通用克隆和优化克隆有限的字母表的广义相空间位移相关的状态。
We show that for any Hilbert-space dimension, the optimal 1-->2 universal quantum cloner can be constructed from essentially the same quantum circuit, i.e., we find a universal design for universal cloners. In the case of infinite dimensions (which includes continuous variable quantum systems) the universal cloner reduces to an essentially classical device. More generally, we construct a universal quantum circuit for distributing qudits in any dimension which acts covariantly under generalized displacements and momentum kicks. The behavior of this covariant distributor is controlled by its initial state. We show that suitable choices for this initial state yield both universal cloners and optimized cloners for limited alphabets of states related by generalized phase-space displacements.