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Related papers: Limitations on Quantum Key Repeaters

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Quantum repeaters enable the generation of reliable entanglement across long distances despite the underlying channel noise. Nevertheless, realizing quantum repeaters poses a difficult engineering challenge due to various device constraints…

Quantum Physics · Physics 2025-12-29 Shin Sun , Daniel Bhatti , Shaobo Gao , David Elkouss , Hiroki Takahashi

Quantum key distribution (QKD) is a method that distributes a secret key to a sender and a receiver by the transmission of quantum particles (e.g. photons). Device-independent quantum key distribution (DIQKD) is a version of QKD with a…

Quantum Physics · Physics 2021-04-27 Matthias Christandl , Roberto Ferrara , Karol Horodecki

Device-independent quantum key distribution (DI-QKD) is a key application of the quantum internet. We report the realization of DI-QKD between two single-atom nodes linked by 100-km fibers. To improve the entangling rate, single-photon…

A Quantum Key Distribution (QKD) protocol describes how two remote parties can establish a secret key by communicating over a quantum and a public classical channel that both can be accessed by an eavesdropper. QKD protocols using…

Information Theory · Computer Science 2020-01-27 Esmaeil Karimi , Emina Soljanin , Philip Whiting

Quantum cryptography is now considered as a promising technology due to its promise of unconditional security. In recent years, rigorous work is being done for the experimental realization of quantum key distribution (QKD) protocols to…

Quantum Physics · Physics 2024-01-02 Satish Kumar , Priya Malpani , Britant , Sandeep Mishra , Anirban Pathak

Quantum key distribution (QKD), the distribution of quantum secured keys useful for data encryption, is expected to have a crucial impact in the next decades. However, although the notable achievements accomplished in the last twenty years,…

Space-based entanglement distribution has the potential to extend the range of quantum communication beyond that achievable through optical fibres that are constrained by exponential losses. Quantum repeaters have been proposed to mitigate…

Standard quantum key distribution (QKD) protocols typically assume that the distant parties share a common reference frame. In practice, however, establishing and maintaining a good alignment between distant observers is rarely a trivial…

Quantum Physics · Physics 2014-04-04 Joshua A. Slater , Cyril Branciard , Nicolas Brunner , Wolfgang Tittel

Memory-assisted quantum key distribution (MA-QKD) systems are among novel promising solutions that can improve the key-rate scaling with channel loss. By using a middle node with quantum storage and measurement functionalities, they offer…

Quantum Physics · Physics 2022-10-25 Guillermo Currás-Lorenzo , Mohsen Razavi

Device-independent quantum key distribution (DIQKD) exploits the violation of a Bell inequality to extract secure key even if the users' devices are untrusted. Currently, all DIQKD protocols suffer from the secret key capacity bound, i.e.,…

Quantum Physics · Physics 2021-04-05 Yuan-Mei Xie , Bing-Hong Li , Yu-Shuo Lu , Xiao-Yu Cao , Wen-Bo Liu , Hua-Lei Yin , Zeng-Bing Chen

A prevalent issue in practical applications of quantum key distribution (QKD) is the emergence of correlations among the emitted signals. Although recent works have proved the security of QKD in the presence of this imperfection, they rest…

Quantum key distribution (QKD) uses individual light quanta in quantum superposition states to guarantee unconditional communication security between distant parties. In practice, the achievable distance for QKD has been limited to a few…

Quantum key distribution (QKD) is a key application in quantum communication, enabling secure key exchange between parties using quantum states. Twin-field (TF) QKD offers a promising solution that surpasses the repeaterless limits, and its…

Quantum Physics · Physics 2025-05-28 Chunfeng Huang , Rui Guan , Xin Liu , Wenjie He , Shizhuo Li , Hao Liang , Ziyang Luo , Zhenrong Zhang , Wei Li , Kejin Wei

We propose a quantum repeater for continuous variable (CV) quantum optical states. Our repeater relies on an error correction protocol for loss on CV states based on CV teleportation and entanglement distillation via noiseless linear…

Quantum Physics · Physics 2015-05-15 Josephine Dias , Tim Ralph

Many papers proved the security of quantum key distribution (QKD) system, in the asymptotic framework. The degree of the security has not been discussed in the finite coding-length framework, sufficiently. However, to guarantee any…

Quantum Physics · Physics 2009-11-13 Masahito Hayashi

Efficient quantum repeaters are needed to combat photon losses in fibers in future quantum networks. Single atom coupled with photonic cavity offers a great platform for photon-atom gate. Here I propose a quantum repeater scheme with…

Quantum Physics · Physics 2026-05-07 Yisheng Lei

The ability to transmit quantum states over long distances is a fundamental requirement of the quantum internet and is reliant upon quantum repeaters. Quantum repeaters involve entangled photon sources that emit and deliver photonic…

We propose a new approach to implement quantum repeaters for long distance quantum communication. Our protocol generates a backbone of encoded Bell pairs and uses the procedure of classical error correction during simultaneous entanglement…

Crucial problems of the quantum Internet are the derivation of stability properties of quantum repeaters and theory of entanglement rate maximization in an entangled network structure. The stability property of a quantum repeater entails…

Quantum Physics · Physics 2020-03-12 Laszlo Gyongyosi , Sandor Imre

W states are a valuable resource for various quantum information tasks, and several protocols to generate them have been proposed and implemented. We introduce a quantum repeater protocol to efficiently distribute three-qubit W states over…

Quantum Physics · Physics 2023-11-09 Jorge Miguel-Ramiro , Ferran Riera-Sàbat , Wolfgang Dür