Most quantum network schemes delay entanglement generation until a request arrives, causing slower processing. To this end, an approach of pre-establishing an initial shared state has emerged. However, the initial shared state must be versatile enough to accommodate all possible requests and may consume considerable qubits. It is crucial to minimize the number of qubits used while satisfying every possible request. We first introduce a 2 -approximation algorithm for the special case where each request consists of only one Bell or GHZ state requirement. Afterward, the 2 -approximation algorithm is extended to handle any possible request that may contain one or more requirements. Finally, via extensive simulation results, we show that our algorithm can outperform existing approaches by up to 29% in used qubits.

Quantum teleportation enables high-security communications via quantum entanglement. However, decoherence, signal decay, and environmental interference may cause imperfect entangled pairs with low fidelity. Such entangled pairs may easily generate errors when used to teleport data qubits and cause fatal computation errors on quantum computers. Fortunately, data qubits can be encoded via quantum error correction (QEC) code to recover the detected error to some extent. Nevertheless, letting any repeaters process data qubits is dangerous because malicious repeaters may peep at, destroy, or fake the data qubits. Thus, in this paper, we propose a novel QEC-enabled routing framework MOON facilitated with the concept of social networks (SNs) for quantum networks (QNs). MOON selects only trusted repeaters to process data qubits and exhibits elastic routing with QEC to maximize the throughput without errors. Last, simulation results show that our framework can outperform existing approaches by up to 34% on network throughput without errors.

The conventional quantum teleportation schemes enable high-security network communications by establishing end-to-end entangled paths. However, those schemes focus on time synchronization and thus cause lots of idle time. Recent research suggests adopting an opportunistic scheme to forward data qubits as far as it can. However, this scheme lacks security since data qubits may be stored at malicious repeaters, which may peek at, destroy, or fake the data qubits. To this end, we design a new scheme called SOAR that considers trusted repeaters via social networks. Moreover, SOAR promotes the parallelism of swapping processes and thus leads to a less idle time of network resources than the other existing schemes. Furthermore, we design an algorithm called SAGE that can best fit SOAR by linking multiple subpaths via appropriate trusted repeaters to get an ideal path and augmenting least-hop paths to utilize the resources in quantum networks better. Simulation results manifest that SOAR outperforms the other schemes by 54%-89%; SAGE outperforms the other routing algorithms by 50% on average on SOAR.

Quantum teleportation via quantum entanglement enables high-security communications in networks. However, if two quantum nodes are far away, it may be difficult to create an entangled path due to the low success probability. Besides, existing approaches neglect social relations among nodes' owners. In this paper, we propose a new framework SEER to minimize the waiting time of all source-destination (SD) pairs' requests. SEER has two promising features: 1) Social-relation Consideration. SEER makes the first attempt to select trusted owners' nodes via social networks as intermediate nodes for requests to temporarily store data qubits to increase the success probability. 2) Starvation Mitigation. SEER divides long SD pairs and slices resources reasonably to remedy starvation due to their low success probability. To this end, we design RATE and PLAN to find the proper intermediate nodes and reduce the average waiting time. Simulation results manifest SEER outperforms others by 37%.