Optimal Routing for Quantum Networks

Abstract

To fully unleash the potentials of quantum computing, several new challenges and open problems need to be addressed. From a routing perspective, the optimal routing problem, i.e., the problem of jointly designing a routing protocol and a route metric assuring the discovery of the route providing the highest quantum communication opportunities between an arbitrary couple of quantum devices, is crucial. In this paper, the optimal routing problem is addressed for generic quantum network architectures composed by repeaters operating through single atoms in optical cavities. Specifically, we first model the entanglement generation through a stochastic framework that allows us to jointly account for the key physical-mechanisms affecting the end-to-end entanglement rate, such as decoherence time, atom-photon and photon-photon entanglement generation, entanglement swapping, and imperfect Bell-state measurement. Then, we derive the closed-form expression of the end-to-end entanglement rate for an arbitrary path and we design an efficient algorithm for entanglement rate computation. Finally, we design a routing protocol and we prove its optimality when used in conjunction with the entanglement rate as routing metric

6G and Beyond: The Future of Wireless Communications Systems

“…In order to overcome this restriction, quantum networks rely on the concept of entanglement [196] described earlier, along with quantum teleportation. The process of quantum teleportation [197] leverages entanglement to transmit unknown quantum states between remote quantum devices, through remote entanglement distribution [198]. Further, as shown in Figure 15, we note the following physical entities that constitute quantum networks [190]:…”

Towards Large-Scale Quantum Networks

“…The specific question of routing entanglement, i.e. making decisions on how end-to-end entanglement can be established quickly between users in future quantum networks, is seeing more attention [12,25,26,46,55,63]. Routing in quantum networks is a nontrivial problem due to the non-local and temporary nature of entangled pairs as well as different physical resource requirements necessary for delivering these pairs with a high enough fidelity.…”

EntangleNet: Theoretical Reestablishment of Entanglement in Quantum Networks †

“…An entanglement distribution scheme was recently proposed as an optimal routing protocol that ensures the greatest entanglement distribution rate between two arbitrary nodes in a quantum network [19]. It operates on a graph model of the network, while taking into account physical challenges such as the stochastic nature of entanglement generation, imperfect Bell measurement and short coherence time T ch of memories in quantum repeaters.…”