We combine the long-distance quantum state transfer and simple operations with the elements of the transferred (nor perfectly) density matrix. These operations are turning some matrix elements to zero, rearranging the matrix elements and preparing their linear combinations with required coefficients. The basic tool performing these operations is the unitary transformation on the extended receiver. A system of linear algebraic equations can be solved in this way as well. Such operations are numerically simulated on the basis of 42-node spin-1/2 chain with the two-qubit sender and receiver.

中文翻译：

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通过扩展接收器上的酉变换对转移密度矩阵的元素进行操作

我们将长距离量子态转移和简单操作与转移（也不是完美）密度矩阵的元素结合起来。这些操作将一些矩阵元素归零，重新排列矩阵元素并准备它们与所需系数的线性组合。执行这些操作的基本工具是扩展接收器上的酉变换。线性代数方程组也可以用这种方式求解。此类操作是基于具有两个量子比特发送器和接收器的 42 节点自旋 1/2 链进行数值模拟的。