On Fidelity-Oriented Entanglement Distribution for Quantum Switches

We consider a star-shaped quantum network with a quantum switch in the center serving a number of requests, each characterized by two non-classical QoS requirements, the end-to-end entanglement delivery rate and the fidelity of the delivered entanglements. The central task of the switch is to allocate the limited entanglement resources among requests to maximize the system performance. We formulate the fundamental entanglement distribution problem where the switch decides 1) which requests to admit, and 2) as multiple requests may share a same quantum link, how to distributed the limited link-level entanglement resources among those competing requests. We then design a framework of joint entanglement purification scheduling and distribution for quantum switches. Our entanglement purification scheduling algorithm seeks to use minimal link-level entanglement resources to satisfy the QoS requirement of a single request. Our entanglement distribution algorithm further allocates the limited entanglement resources among multiple requests to maximize the overall utility by integrating the designed entanglement purification scheduling algorithm. We establish theoretical performance guarantee of our proposition, which is complemented by extensive numerical experiments demonstrating its effectiveness in a variety of network settings.