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 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. To reduce EP generation latency, prior works have looked at selection of efficient entanglement-routing paths and simultaneous use of multiple such paths for EP generation. In this paper, we propose and investigate a complementary technique to reduce EP generation latency--to pre-distribute EPs over certain (pre-determined) pairs of network nodes; these pre-distributed EPs can then be used to generate EPs for the requested pairs, when needed, with lower generation latency. For such an pre-distribution approach to be most effective, we need to address an optimization problem of selection of node-pairs where the EPs should be pre-distributed to minimize the generation latency of expected EP requests, under a given cost constraint. In this paper, we appropriately formulate the above optimization problem and design two efficient algorithms, one of which is a greedy approach based on an approximation algorithm for a special case. Via extensive evaluations over the NetSquid simulator, we demonstrate the effectiveness of our approach and developed techniques; we show that our developed algorithms outperform a naive approach by up to an order of magnitude.
翻译:量子网络通信具有挑战性,因为量子系统中的不克隆定理使许多古典技术无法适用。对于长距离通信,唯一可行的方法是将量子状态传送,这要求事先分配离心对方的量子;在偏僻节点上建立电源源,由于基本物理过程成功概率低,可能会出现显著的悬浮。为了减少EP产生延迟,先前的工作已经研究了高效的纠缠路由路径选择以及同时为EP一代同时使用多种此类路径。在本文中,我们提议并调查一种互补技术,以减少EP产生拉线对等(预先确定的)对方的量子。这些预先分配的量子网络节点可以在需要时产生对所请求的对等相配方的量。为了降低 EP 分配前的方法最为有效,我们需要解决一个最优化的选用不记分辨定路路路道的方法。 一种基于我们所开发的纸面要求的精度, 一种基于我们所开发的精度的精度的精度, 一种基于我们所开发的纸面要求的精度的精度的精度, 一种我们所开发的精度的对精度, 一种我们所研细的造的造的造纸面的精度, 一种我们所研磨的造的精度,一种我们所研磨的精度, 一种我们所研磨的精度的精度, 一种我们所研磨的精细的精细的造的造的精度,一个我们所研磨的精度的精度,一个我们所研磨的造的精度的精度的精度的精细的造的造的精度, 。