End-To-End Capacities of Hybrid Quantum Networks

Abstract

Future quantum networks will be hybrid structures, constructed from complex architectures of quantum repeaters interconnected by quantum channels that describe a variety of physical domains; predominantly optical-fiber and free-space links. In this hybrid setting, the interplay between the channel quality within network sub-structures must be carefully considered, and is pivotal for ensuring high-rate end-to-end quantum communication. In this work, we combine recent advances in the theory of point-to-point free-space channel capacities and end-to-end quantum network capacities in order to develop critical tools for the study of hybrid, free-space quantum networks. We present a general formalism for studying the capacities of arbitrary, hybrid quantum networks, before specifying to the regime of atmospheric and space-based quantum channels. We then introduce a class of modular quantum network architectures which offer a realistic and readily analysable framework for hybrid quantum networks. By considering a physically motivated, highly connected modular structure we are able to idealize network performance and derive channel conditions for which optimal performance is guaranteed. This allows us to reveal vital properties for which distance-independent rates are achieved, so that the end-to-end capacity has no dependence on the physical separation between users. Our analytical method elucidates key infrastructure demands for a future satellitebased global quantum internet, and for hybrid wired/wireless metropolitan quantum networks.

Complex quantum networks: a topical review

“…There are many excellent contemporary treatises on the topic [3,[400][401][402], however here a more concise account of the field is provided with a unique point of view emphasizing the network aspect. In particular, we focus on research where the architecture is fixed and it is asked what kind of topology it tends to lead to [403,404] or how a given topology controls its performance [405][406][407][408]. To this end we will also briefly introduce the relevant architectures.…”

“…In particular, it turns out that under reasonable additional assumptions and a fixed protocol a fiber network leads to a Poisson degree distribution but a satellite network to a log-normal distribution. We also present results showing how satellites are a game changer in long haul communications, making them a strong candidate for a backbone that connects smaller networks together [408,454].…”

“…As a side note, the classical capacities are still very rarely taken into account although they affect both use cases [450] as well as efficiency of QKD [492] and presumably other applications. Both sneakernet [401,491] and satellite links [408,454] have been proposed as the backbone for the quantum Internet. The backbone would stitch together networks where distances are in the short or intermediate regime.…”

First Request First Service Entanglement Routing Scheme for Quantum Networks

“…Recently, reconfigurable and flexible entanglement networks were established with wavelength selective switches (WSS), where adaptive bandwidth management was performed to satisfy the dynamic connection demands of distant users [ 35 , 36 , 37 , 38 , 39 , 40 , 41 ]. Therefore, the entanglement routing with active wavelength multiplexing schemes is desiderated for constructing entanglement distribution networks with various topologies [ 42 , 43 , 44 , 45 ]. In the meantime, existing quantum routing schemes [ 2 , 46 , 47 , 48 , 49 , 50 , 51 , 52 ] are mainly focused on trusted node networks and quantum memory-assisted networks, and cannot be applied to quantum entanglement distribution networks, where time division multiplexing (TDM) and wavelength division multiplexing (WDM) techniques need to be adopted to forward entangled photons.…”