Quantum switches are envisioned to be an integral component of future entanglement distribution networks. They can provide high quality entanglement distribution service to end-users by performing quantum operations such as entanglement swapping and entanglement purification. In this work, we characterize the capacity region of such a quantum switch under noisy channel transmissions and imperfect quantum operations. We express the capacity region as a function of the channel and network parameters (link and entanglement swap success probability), entanglement purification yield and application level parameters (target fidelity threshold). In particular, we provide necessary conditions to verify if a set of request rates belong to the capacity region of the switch. We use these conditions to find the maximum achievable end-to-end user entanglement generation throughput by solving a set of linear optimization problems. We develop a max-weight scheduling policy and prove that the policy stabilizes the switch for all feasible request arrival rates. As we develop scheduling policies, we also generate new results for computing the conditional yield distribution of different classes of purification protocols. From numerical experiments, we discover that performing link-level entanglement purification followed by entanglement swaps provides a larger capacity region than doing entanglement swaps followed by end-to-end entanglement purification. The conclusions obtained in this work can yield useful guidelines for subsequent quantum switch designs.

翻译：量子开关被认为是未来缠绕分配网络的一个组成部分。 它们可以通过执行缠绕互换和缠绕净化等量子操作,向终端用户提供高质量的缠绕分配服务。 在这项工作中, 我们将这种量子开关的能力区域定性为噪音的频道传输和不完善的量子操作。 我们把能力区域表述为频道和网络参数( 链接和缠绕互换成功概率)、 缠绕净产值和应用水平参数( 目标对等临界值阈值)的函数。 我们尤其提供必要的条件, 以核实一套请求率是否属于开关能力区域。 我们利用这些条件来寻找最大可实现的端对端用户纠缠绕生成量, 解决一系列线性优化问题。 我们制定了最大量的时间安排政策, 并证明政策稳定了所有可行申请抵达率的开关。 随着我们制定时间安排政策, 我们还在计算不同类别净化协议的有条件收益分配方面产生了新的结果。 我们从数字实验中发现, 在进行连系缠绕式互换后, 以更大型的递动性净化调整后, 能够做出更大的递接式递接结果。