Adaptive bandwidth management for entanglement distribution in quantum networks

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.

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Adaptive bandwidth binning for bandwidth management

Computer Networks ◽

10.1016/j.comnet.2018.12.019 ◽

2019 ◽

Vol 150 ◽

pp. 150-169 ◽

Cited By ~ 2

Author(s):

Gongbing Hong ◽

James Martin ◽

James Westall

Keyword(s):

Bandwidth Management ◽

Adaptive Bandwidth

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Drone-based entanglement distribution towards mobile quantum networks

National Science Review ◽

10.1093/nsr/nwz227 ◽

2020 ◽

Vol 7 (5) ◽

pp. 921-928 ◽

Cited By ~ 2

Author(s):

Hua-Ying Liu ◽

Xiao-Hui Tian ◽

Changsheng Gu ◽

Pengfei Fan ◽

Xin Ni ◽

...

Keyword(s):

Quantum Communication ◽

Single Mode ◽

Cost Effective ◽

Local Area ◽

Single Mode Fiber ◽

Full Time ◽

Mobile Platforms ◽

Quantum Networks ◽

Entanglement Distribution ◽

Scalable Design

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.

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