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We study the equivalence between a realistic quantum key distribution protocol using coherent states and homodyne detection and a formal entanglement purification protocol. Maximally-entangled qubit pairs that one can extract in the formal…

Quantum Physics · Physics 2007-05-23 G. Van Assche , S. Iblisdir , N. J. Cerf

We analyze an entanglement-based quantum key distribution (QKD) architecture that uses a linear chain of quantum repeaters employing photon-pair sources, spectral-multiplexing, linear-optic Bell-state measurements, multi-mode quantum…

High-dimensional entanglement has shown to have significant advantages in quantum communication. It is available in many degrees of freedom and in particular in the time-domain routinely produced in down-conversion (SPDC). While…

Quantum Physics · Physics 2024-11-22 Alexandra Bergmayr , Florian Kanitschar , Matej Pivoluska , Marcus Huber

We present a fiber-based continuous-variable quantum key distribution system. In the scheme, a quantum signal of two non-orthogonal weak optical coherent states is sent through a fiber-based quantum channel. The receiver simultaneously…

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

We introduce a ternary quantum key distribution (QKD) protocol and asymptotic security proof based on three coherent states and homodyne detection. Previous work had considered the binary case of two coherent states and here we nontrivially…

Quantum Physics · Physics 2018-02-14 Kamil Bradler , Christian Weedbrook

We present a protocol for quantum key distribution using discrete modulation of coherent states of light. Information is encoded in the variable phase of coherent states which can be chosen from a regular discrete set ranging from binary to…

Quantum Physics · Physics 2015-05-13 Denis Sych , Gerd Leuchs

The Quantum Key Distribution protocol can encode a single quantum state and implements an information-theoretically secure key distribution protocol in communication. In the actual QKD experimental system, there are usually two encoding…

Quantum Physics · Physics 2020-08-26 Gao Feifei , Li Zhihui , Liu Chengji , Han Duo

We investigate the security of continuous-variable (CV) quantum key distribution (QKD) using coherent states in the presence of quadrature excess noise. We consider an eavesdropping attack which uses a linear amplifier and beam splitter.…

Quantum Physics · Physics 2009-11-11 Ryo Namiki , Takuya Hirano

We show that weakly entangled states can improve communication over a qubit channel using only separate, interference-free, measurements of individual photons. We introduce a communication task corresponding to the cryptographic primitive…

Quantum key distribution (QKD) is theoretically secure using the principle of quantum mechanics; therefore, QKD is a promising solution for the future of secure communication. Although several experimental demonstrations of QKD have been…

Quantum Physics · Physics 2022-02-02 Chunfeng Huang , Ye Chen , Long Jin , Minming Geng , Junwei Wang , Zhenrong Zhang , Kejin Wei

Protocols for probabilistic entanglement-assisted quantum teleportation and for entanglement swapping of material qubits are presented. They are based on a protocol for postselective Bell-state projection which is capable of projecting two…

Quantum Physics · Physics 2014-07-04 J. M. Torres , J. Z. Bernád , G. Alber

We assess the security of a quantum key distribution protocol relying on the transmission of Gaussian-modulated coherent states and homodyne detection. This protocol is shown to be equivalent to a squeezed state protocol based on a CSS code…

Quantum Physics · Physics 2009-11-10 S. Iblisdir , G. Van Assche , N. J. Cerf

We propose an efficient quantum key distribution scheme based on entanglement. The sender chooses pairs of photons in one of the two equivalent nonmaximally entangled states randomly, and sends a sequence of photons from each pair to the…

Quantum Physics · Physics 2009-11-07 Peng Xue , Chuan-Feng Li , Guang-Can Guo

An entanglement witness approach to quantum coherent state key distribution and a system for its practical implementation are described. In this approach, eavesdropping can be detected by a change in sign of either of two witness functions,…

Quantum Physics · Physics 2015-06-16 David S. Simon , Gregg Jaeger , Alexander V. Sergienko

Quantum key distribution (QKD) based on coherent states is well known for its implementation simplicity, but it suffers from loss-dependent attacks based on optimal unambiguous state discrimination. Crucially, previous research has…

Quantum Physics · Physics 2020-06-05 Li Liu , Yukun Wang , Emilien Lavie , Arno Ricou , Chao Wang , Fen Zhuo Guo , Charles Ci Wen Lim

Entanglement distribution is key to the success of secure communication schemes based on quantum mechanics, and there is a strong need for an ultimate architecture able to overcome the limitations of recent proposals such as those based on…

Quantum Physics · Physics 2015-09-10 Alexander Streltsov , Remigiusz Augusiak , Maciej Demianowicz , Maciej Lewenstein

Quantum key distribution (QKD) allows two users to exchange a provably secure key for cryptographic applications. In prepare-and-measure QKD protocols, the states must be indistinguishable to prevent information leakage to an eavesdropper…

The security of measurement device-independent quantum key distribution (MDI QKD) relies on a thorough characterization of one's optical source output, especially any noise in the state preparation process. Here, we provide an extension of…

Quantum Physics · Physics 2021-01-04 J. Eli Bourassa , Ignatius William Primaatmaja , Charles Ci Wen Lim , Hoi-Kwong Lo

Quantum communication in general helps deter potential eavesdropping in the course of transmission of bits to enable secure communication between two or more parties. In this paper, we propose a novel quasi-deterministic secure quantum…

Quantum Physics · Physics 2021-03-08 Sujan Vijayaraj , S. Balakrishnan , K. Senthilnathan