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Related papers: Limitations on Quantum Key Repeaters

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Quantum communication relies on the existence of entanglement between two nodes of a network. However, due to its fragile nature, it is nearly impossible to establish entanglement at large distances through the direct transmission of…

Quantum Physics · Physics 2021-10-18 Sowmitra Das , Md. Saifur Rahman , Mahbub Majumdar

Twin-field (TF) quantum key distribution (QKD) fundamentally alters the rate-distance relationship of QKD, offering the scaling of a single-node quantum repeater. Although recent experiments have demonstrated the new opportunities for…

Quantum key distribution allows for the generation of a secret key between distant parties connected by a quantum channel such as optical fibre or free space. Unfortunately, the rate of generation of a secret key by direct transmission is…

Quantum key distribution (QKD) is a cryptographic method enabling two parties to establish a private encryption key. The range of communication of ground-based QKD is limited to an order of 100km, due to in-fibre attenuations and…

Quantum Physics · Physics 2019-12-04 Olivia Lee , Tom Vergoossen

Quantum key distribution (QKD) enables information-theoretic secure communication, yet its ultimate tolerance to noise and achievable transmission distance remain fundamentally constrained. We establish the maximum quantum bit error rate…

Quantum Physics · Physics 2026-02-27 Stefano Pirandola

The feasibility of trust-free long-haul quantum key distribution (QKD) networks is addressed. We combine measurement-device-independent QKD (MDI-QKD), as an access technology, with a quantum repeater setup, at the core of future quantum…

Quantum Physics · Physics 2016-03-02 Nicoló Lo Piparo , Mohsen Razavi

Quantum key distribution (QKD) enables two remote parties to grow a shared key which they can use for unconditionally secure communication [1]. The applicable distance of a QKD protocol depends on the loss and the excess noise of the…

Quantum Physics · Physics 2012-10-08 Lars S. Madsen , Vladyslav C. Usenko , Mikael Lassen , Radim Filip , Ulrik L. Andersen

We introduce an alternative type of quantum repeater for long-range quantum communication with improved scaling with the distance. We show that by employing hashing, a deterministic entanglement distillation protocol with one-way…

Quantum Physics · Physics 2018-01-24 M. Zwerger , A. Pirker , V. Dunjko , H. J. Briegel , W. Dür

We present a "hybrid quantum repeater" protocol for the long-distance distribution of atomic entangled states beyond qubits. In our scheme, imperfect noisy entangled pairs of two qudits, i.e., two discrete-variable $d$-level systems, each…

Quantum Physics · Physics 2019-04-03 Marcel Bergmann , Peter van Loock

Quantum communications promise to revolutionise the way information is exchanged and protected. Unlike their classical counterpart, they are based on dim optical pulses that cannot be amplified by conventional optical repeaters.…

Quantum Physics · Physics 2019-10-07 M. Minder , M. Pittaluga , G. L. Roberts , M. Lucamarini , J. F. Dynes , Z. L. Yuan , A. J. Shields

High-quality long-distance entanglement is essential for both quantum communication and scalable quantum networks. Entanglement purification is to distill high-quality entanglement from low-quality entanglement in a noisy environment and it…

Entanglement based quantum communication offers an increased level of security in practical secret shared key distribution. One of the fundamental principles enabling this security -- the fact that interfering with one photon will destroy…

We propose a post-selection technique, based on quantum error detection, for quantum key distribution (QKD) systems that run over quantum repeaters with encoding. In such repeaters, quantum error correction techniques are used for…

Quantum Physics · Physics 2021-01-04 Yumang Jing , Daniel Alsina Leal , Mohsen Razavi

Realizing large-scale quantum networks requires the generation of high-fidelity quantum entanglement states between remote quantum nodes, a key resource for quantum communication, distributed computation and sensing applications. However,…

Quantum repeaters are essential for achieving long-distance quantum communication due to photon loss, which grows exponentially with the channel distance. Current quantum repeater generations use entanglement distillation protocols, where…

Quantum Physics · Physics 2025-10-09 Iftach Yakar , Michael Ben-Or

Quantum repeater networks that allow long-distance entanglement distribution will be the backbone of distributed quantum information processing. In this paper we explore entanglement distribution using quantum repeaters with optimized…

Quantum optical states are fragile and can become corrupted when passed through a lossy communication channel. Unlike for classical signals, optical amplifiers cannot be used to recover quantum signals. Quantum repeaters have been proposed…

Quantum Physics · Physics 2017-02-15 Josephine Dias , Timothy C Ralph

We present a quantum repeater protocol for distributing entanglement over long distances, where a dedicated communication stage enables trial rates not limited by the travel time between repeater nodes. To accomplish this, each node…

Quantum Physics · Physics 2025-04-25 Adam Kinos , Andreas Walther , Stefan Kröll , Lars Rippe

As quantum key distribution becomes increasingly practical, questions of how to effectively employ it in large-scale networks and over large distances becomes increasingly important. To that end, in this work, we model the performance of…

Quantum Physics · Physics 2020-08-03 Omar Amer , Walter O. Krawec , Bing Wang

Long-distance quantum communication requires reliable entanglement distribution, but direct generation with protocols such as Barrett--Kok suffers from exponentially decreasing success probability with distance, making it impractical over…

Quantum Physics · Physics 2025-10-10 Wenhan Li , Shiyu Zhang