Quantum network communication is challenging, as the No-cloning theorem in quantum regime makes many classical techniques inapplicable. For long-distance communication, the only viable communication approach is teleportation of quantum states, which requires a prior distribution of entangled pairs (EPs) of qubits. Establishment of EPs across remote nodes can incur significant latency due to the low probability of success of the underlying physical processes. The focus of our work is to develop efficient techniques that minimize EP generation latency. Prior works have focused on selecting entanglement paths; in contrast, we select entanglement swapping trees--a more accurate representation of the entanglement generation structure. We develop a dynamic programming algorithm to select an optimal swapping-tree for a single pair of nodes, under the given capacity and fidelity constraints. For the general setting, we develop an efficient iterative algorithm to compute a set of swapping trees. We present simulation results which show that our solutions outperform the prior approaches by an order of magnitude and are viable for long-distance entanglement generation.

翻译：量子网络通信具有挑战性，因为量子领域的不可克隆定理使得许多经典技术无法适用。对于远距离通信而言，唯一可行的通信方式是通过量子态隐形传态，这需要预先分布量子比特的纠缠对。由于底层物理过程的成功概率较低，跨远程节点建立纠缠对可能产生显著延迟。本研究的重点是开发最小化纠缠对生成延迟的高效技术。以往工作侧重于选择纠缠路径；相比之下，我们选择纠缠交换树——一种更准确的纠缠生成结构表示方式。我们提出了一种动态规划算法，在给定容量和保真度约束条件下，为单对节点选择最优纠缠交换树。针对一般场景，我们开发了一种高效迭代算法来计算一组交换树。仿真结果表明，我们的解决方案比现有方法性能提升一个数量级，并且适用于远距离纠缠生成。