Multipartite state generation in quantum networks with optimal scaling

Wallnöfer, Julius; Pirker, Alexander; Zwerger, Michael; Dür, W.

doi:10.1038/s41598-018-36543-5

Cited by 30 publications

(23 citation statements)

References 50 publications

(116 reference statements)

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“…In this way, we may achieve better long-distance scalings and further boost the rates by resorting to more complex routing strategies. The study of quantum repeaters and secure QKD networks is one of the hottest topics today [39][40][41][42][43][44][45][46][47][48].…”

Section: Imentioning

confidence: 99%

Advances in quantum cryptography

et al. 2020

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Section: Imentioning

confidence: 99%

Advances in quantum cryptography

et al. 2020

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“…If network devices would share only Bell-pairs among each other, then, depending on the requested graph states, the network devices have to apply more CZ gates, Bell-measurements and single qubit measurements in the Y or Z basis in contrast to a multipartite approach. Observe that if these operations are noisy, this will result in a state of smaller fidelity compared to directly using multipartite quantum states, see [76]. Furthermore, such a direct multipartite approach offers a storage advantage compared to bipartite schemes [51,76].…”

Section: Quantum Networkmentioning

confidence: 99%

“…Observe that if these operations are noisy, this will result in a state of smaller fidelity compared to directly using multipartite quantum states, see [76]. Furthermore, such a direct multipartite approach offers a storage advantage compared to bipartite schemes [51,76].…”

Section: Quantum Networkmentioning

confidence: 99%

“…On this layer, the techniques for establishing long-distance quantum communications reside. In particular, concrete technologies include quantum repeaters, bi- [28][29][30][31][32][33][34][36][37][38][39][40][41][42][43][44][45][46][47][48][49] or multipartite [57,76], but also the direct transmission of encoded quantum states [23][24][25][26] or percolation approaches [82,83] which generate entanglement structures in a noisy quantum network of networking devices by applying techniques from percolation theory. The main purpose of devices operating on this layer is to enable point-to-point or point-to-multipoint long-distance connectivity without any notion of requests.…”

Section: Layer 2-connectivity Layermentioning

confidence: 99%

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A quantum network stack and protocols for reliable entanglement-based networks

2019

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We present a stack model for breaking down the complexity of entanglement-based quantum networks. More specifically, we focus on the structures and architectures of quantum networks and not on concrete physical implementations of network elements. We construct the quantum network stack in a hierarchical manner comprising several layers, similar to the classical network stack, and identify quantum networking devices operating on each of these layers. The layers responsibilities range from establishing point-to-point connectivity, over intra-network graph state generation, to inter-network routing of entanglement. In addition we propose several protocols operating on these layers. In particular, we extend the existing intra-network protocols for generating arbitrary graph states to ensure reliability inside a quantum network, where here reliability refers to the capability to compensate for devices failures. Furthermore, we propose a routing protocol for quantum routers which enables the generation of arbitrary graph states across network boundaries. This protocol, in correspondence with classical routing protocols, can compensate dynamically for failures of routers, or even complete networks, by simply re-routing the given entanglement over alternative paths. We also consider how to connect quantum routers in a hierarchical manner to reduce complexity, as well as reliability issues arising in connecting these quantum networking devices. quantum network shall not be limited to the generation of Bell-pairs only [50][51][52][53], because many interesting applications require multipartite entangled quantum states. Therefore, the ultimate goal of quantum networks should be to enable their clients to share arbitrary entangled states to perform distributed quantum computational tasks. An important subclass of multipartite entangled states are so-called graph states [54], and many protocols in quantum information theory rely on this class of states.Here we consider entanglement-based quantum networks utilizing multipartite entangled states [51-53, 55-57] which are capable of generating arbitrary graph states among clients. In general, we identify three successive phases in entanglement-based quantum networks: dynamic, static, and adaptive. In the dynamic phase, which is the first phase, the quantum network devices utilize the quantum channels to distribute entangled states among each other. Once this phase completes, the quantum network devices share certain entangled quantum states, which results in the static phase. In this phase, the quantum network devices store these entangled states for future requests locally. Finally, in the adaptive phase, the network devices manipulate and adapt the entangled states of the static phase. This might be caused either due to requests of clients in networks, but also due to failures of devices in a quantum network.We follow the approach of [51] where a certain network state is stored in the static phase, and client requests to establish certain target (graph) states in the network ar...

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“…Bell measurements are typically used to obtain long-range bipartite entanglement, while multi-qubit measurements can be made in order to generate multipartite entanglement; see, e.g., Refs. [65][66][67][68][69][70][71][72][73][74][75][76].…”

Section: Network Architectures and Entanglement Distribution Protocolsmentioning

confidence: 99%

Practical figures of merit and thresholds for entanglement distribution in quantum networks

Khatri

Matyas

Siddiqui

et al. 2019

Phys. Rev. Research

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Before global-scale quantum networks become operational, it is important to consider how to evaluate their performance so that they can be suitably built to achieve the desired performance. In this work, we consider three figures of merit for the performance of a quantum network: the average global connection time, the average point-to-point connection time, and the average largest entanglement cluster size. These three quantities are based on the generation of elementary links in a quantum network, which is a crucial initial requirement that must be met before any long-range entanglement distribution can be achieved. We evaluate these figures of merit for a particular class of quantum repeater protocols consisting of repeat-until-success elementary link generation along with entanglement swapping at intermediate nodes in order to achieve long-range entanglement. We obtain lower and upper bounds on these three quantities, which lead to requirements on quantum memory coherence times and other aspects of quantum network implementations. Our bounds are based solely on the inherently probabilistic nature of elementary link generation in quantum networks, and they apply to networks with arbitrary topology. CONTENTS

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Multipartite state generation in quantum networks with optimal scaling

Cited by 30 publications

References 50 publications

Advances in quantum cryptography

Advances in quantum cryptography

A quantum network stack and protocols for reliable entanglement-based networks

Practical figures of merit and thresholds for entanglement distribution in quantum networks

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