scholarly journals Functional Quantum Nodes for Entanglement Distribution over Scalable Quantum Networks

Science ◽  
2007 ◽  
Vol 316 (5829) ◽  
pp. 1316-1320 ◽  
Author(s):  
C.-W. Chou ◽  
J. Laurat ◽  
H. Deng ◽  
K. S. Choi ◽  
H. de Riedmatten ◽  
...  
Author(s):  
Yuan Lee ◽  
Eric Bersin ◽  
Axel Dahlberg ◽  
Stephanie Wehner ◽  
Dirk Englund

Optica ◽  
2021 ◽  
Author(s):  
Navin Lingaraju ◽  
Hsuan-Hao Lu ◽  
Suparna Seshadri ◽  
Daniel Leaird ◽  
Andrew Weiner ◽  
...  

Quantum ◽  
2021 ◽  
Vol 5 ◽  
pp. 537
Author(s):  
Sumeet Khatri

Distributing entanglement over long distances is one of the central tasks in quantum networks. An important problem, especially for near-term quantum networks, is to develop optimal entanglement distribution protocols that take into account the limitations of current and near-term hardware, such as quantum memories with limited coherence time. We address this problem by initiating the study of quantum network protocols for entanglement distribution using the theory of decision processes, such that optimal protocols (referred to as policies in the context of decision processes) can be found using dynamic programming or reinforcement learning algorithms. As a first step, in this work we focus exclusively on the elementary link level. We start by defining a quantum decision process for elementary links, along with figures of merit for evaluating policies. We then provide two algorithms for determining policies, one of which we prove to be optimal (with respect to fidelity and success probability) among all policies. Then we show that the previously-studied memory-cutoff protocol can be phrased as a policy within our decision process framework, allowing us to obtain several new fundamental results about it. The conceptual developments and results of this work pave the way for the systematic study of the fundamental limitations of near-term quantum networks, and the requirements for physically realizing them.


2020 ◽  
Vol 7 (5) ◽  
pp. 921-928 ◽  
Author(s):  
Hua-Ying Liu ◽  
Xiao-Hui Tian ◽  
Changsheng Gu ◽  
Pengfei Fan ◽  
Xin Ni ◽  
...  

Abstract Satellites have shown free-space quantum-communication ability; however, they are orbit-limited from full-time all-location coverage. Meanwhile, practical quantum networks require satellite constellations, which are complicated and expensive, whereas the airborne mobile quantum communication may be a practical alternative to offering full-time all-location multi-weather coverage in a cost-effective way. Here, we demonstrate the first mobile entanglement distribution based on drones, realizing multi-weather operation including daytime and rainy nights, with a Clauser-Horne-Shimony-Holt S-parameter measured to be 2.41 ± 0.14 and 2.49 ± 0.06, respectively. Such a system shows unparalleled mobility, flexibility and reconfigurability compared to the existing satellite and fiber-based quantum communication, and reveals its potential to establish a multinode quantum network, with a scalable design using symmetrical lens diameter and single-mode-fiber coupling. All key technologies have been developed to pack quantum nodes into lightweight mobile platforms for local-area coverage, and arouse further technical improvements to establish wide-area quantum networks with high-altitude mobile communication.


2008 ◽  
Vol 77 (2) ◽  
Author(s):  
Sébastien Perseguers ◽  
J. Ignacio Cirac ◽  
Antonio Acín ◽  
Maciej Lewenstein ◽  
Jan Wehr

2018 ◽  
Vol 8 (10) ◽  
pp. 1935
Author(s):  
Mihai-Zicu Mina ◽  
Pantelimon Popescu

In the practical context of quantum networks, the most reliable method of transmitting quantum information is via teleportation because quantum states are highly sensitive. However, teleportation consumes a shared maximally entangled state. Two parties Alice and Bob located at separate nodes that wish to reestablish their shared entanglement will not send entangled qubits directly to achieve this goal, but rather employ a more efficient mechanism that ensures minimal time resources. In this paper, we present a quantum routing scheme that exploits entanglement swapping to reestablish consumed entanglement. It improves and generalizes previous work on the subject and reduces the entanglement distribution time by a factor of 4 k in an arbitrary scale quantum network, where N = 4 k - 1 is a required number of quantum nodes located between source and destination. In addition, k is the greatest positive integer considered by Alice or Bob, such that afterwards they choose N quantum switches.


2006 ◽  
Vol 84 (6-7) ◽  
pp. 639-644
Author(s):  
B C Sanders ◽  
G Gour ◽  
D A Meyer

We present a powerful theorem for tripartite remote entanglement distribution protocols, which provides an operational interpretation of concurrence as a type of entanglement capacity, and we establish that concurrence of assistance, which we show is an entanglement monotone, identifies capabilities of and limitations to producing pure bipartite entangled states from pure tripartite entangled states. In addition, we show that, if concurrence of assistance for the pure tripartite state is at least as large as the concurrence of the desired pure bipartite state, then the former may be transformed to the latter via local operations and classical communication, and we calculate the maximum probability for this transformation when this condition is not met.PACS Nos.: 03.67.Mn, 03.67.Hk, 03.65.Ud


2019 ◽  
Vol 1 (2) ◽  
Author(s):  
Sumeet Khatri ◽  
Corey T. Matyas ◽  
Aliza U. Siddiqui ◽  
Jonathan P. Dowling

2022 ◽  
Vol 12 (2) ◽  
pp. 701
Author(s):  
Jianxiong Liang ◽  
Xiaoguang Chen ◽  
Tianyi Wang

Quantum networks have good prospects for applications in the future. Compared with classical networks, small-world quantum networks have some interesting properties. The topology of the network can be changed through entanglement exchange operations, and different network topologies will result in different percolation thresholds when performing entanglement percolation. A lower percolation threshold means that quantum networks require fewer minimum resources for communication. Since a shared singlet between two nodes can still be a limitation, concurrency percolation theory (ConPT) can be used to relax the condition. In this paper, we investigate how entanglement distribution is performed in small-world quantum networks to ensure that nodes in the network can communicate with each other by establishing communication links through entanglement swapping. Any node can perform entanglement swapping on only part of the connected edges, which can reduce the influence of each node in the network during entanglement swapping. In addition, the ConPT method is used to reduce the percolation threshold even further, thus obtaining a better network structure and reducing the resources required.


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