Article
Optics
Olena Kovalenko, Young-Sik Ra, Yin Cai, Vladyslav C. Usenko, Claude Fabre, Nicolas Treps, Radim Filip
Summary: Quantum key distribution using continuous variables offers high-speed, low-noise homodyne detection and can achieve secure key transmission over long distances. Increasing system clock rates and frequency-mode-multiplexing can further enhance the secret key rate.
PHOTONICS RESEARCH
(2021)
Article
Multidisciplinary Sciences
Nitin Jain, Hou-Man Chin, Hossein Mani, Cosmo Lupo, Dino Solar Nikolic, Arne Kordts, Stefano Pirandola, Thomas Brochmann Pedersen, Matthias Kolb, Bernhard Omer, Christoph Pacher, Tobias Gehring, Ulrik L. Andersen
Summary: This paper introduces a continuous-variable quantum key distribution (CVQKD) protocol that can generate composable keys secure against collective attacks. By using Gaussian-modulated coherent states and improving the security proof and system operation, this CVQKD protocol overcomes the difficulty of key generation in existing protocols. This advance brings CVQKD implementations closer to their discrete-variable counterparts in terms of practicality, performance, and security.
NATURE COMMUNICATIONS
(2022)
Article
Quantum Science & Technology
Aurelie Denys, Peter Brown, Anthony Leverrier
Summary: The study establishes an analytical lower bound for continuous-variable quantum key distribution, supporting efficient modulation schemes and proposing a solution suitable for large-scale deployment.
Article
Optics
Ping Wang, Peng Huang, Rui Chen, Guihua Zeng
Summary: Free-space continuous-variable quantum key distribution (CV-QKD) requires precise frame synchronization, and the fluctuation of channel transmittance increases the difficulty of synchronization. A novel method of inserting synchronization frames has been proposed and tested for feasibility and efficiency.
Article
Physics, Multidisciplinary
Qin Liao, Gang Xiao, Shaoliang Peng
Summary: This study investigates a practical scenario where the signal source is no longer protected and is placed in an untrusted atmospheric channel, leading to a reduction in the performance of ACVQKD. However, it is found that the performance can be improved by adopting a photon subtraction operation.
Article
Optics
Olena Kovalenko, Vladyslav C. Usenko, Radim Filip
Summary: Two-mode squeezed states are scalable and robust entanglement resources for quantum information protocols;
Optimizing initial squeezing, relative phase, and linear coupling can reduce the degradation of Gaussian entanglement in the presence of crosstalk;
Compensating crosstalk through mode interference improves the efficiency of using multimode continuous-variable photonic entanglement in quantum networks.
Article
Quantum Science & Technology
Twesh Upadhyaya, Thomas van Himbeeck, Jie Lin, Norbert Lutkenhaus
Summary: We propose a method to connect the infinite-dimensional description of optical continuous-variable QKD protocols to a finite-dimensional formulation, allowing for evaluation of secure key rates using reliable numerical methods. Our approach yields asymptotic key rates for discrete-modulated continuous-variable QKD protocols, offering practical advantages and avoiding the photon-number cutoff assumption used in previous works. This method also demonstrates benefits over existing techniques when applied to discrete-variable protocols.
Article
Quantum Science & Technology
Nitin Jain, Ivan Derkach, Hou-Man Chin, Radim Filip, Ulrik L. Andersen, Vladyslav C. Usenko, Tobias Gehring
Summary: This study identified a modulation leakage vulnerability in continuous-variable quantum key distribution systems, caused by inadequate suppression of certain sidebands during modulation. The leakage was found to impact the range of secret key obtainment and could potentially lead to security breaches, with additional trusted noise proving effective in countering this vulnerability.
QUANTUM SCIENCE AND TECHNOLOGY
(2021)
Article
Optics
Shaoping Shi, Yajun Wang, Long Tian, Wei Li, Yimiao Wu, Qingwei Wang, Yaohui Zheng, Kunchi Peng
Summary: This article presents a fully connected continuous-variable quantum teleportation network architecture, where a squeezed state of light distributes entangled sideband modes to each communication link, offering potential for various tasks of quantum information processing.
LASER & PHOTONICS REVIEWS
(2023)
Article
Mathematics
Yiwu Zhu, Lei Mao, Hui Hu, Yijun Wang, Ying Guo
Summary: The article discusses the negative impact of analog-to-digital converter's finite sampling bandwidth on continuous-variable quantum key distribution, and proposes a method to enhance system security using an adaptive optics unit. The research demonstrates the feasibility of this method for CVQKD in realistic free-space environments through numerical simulations.
Article
Physics, Multidisciplinary
Pu Wang, Yu Zhang, Zhenguo Lu, Xuyang Wang, Yongmin Li
Summary: Discrete-modulation continuous-variable (CV) quantum key distribution has the potential for large-scale deployment in secure quantum communication networks due to its low implementation complexity and compatibility with current coherent optical telecommunication. However, current protocols require large constellation sizes for comparable key rates to Gaussian modulation. This study demonstrates that a high key rate comparable to Gaussian modulation can be achieved using only ten or so coherent states through suitable key mapping and numerical convex optimization techniques.
NEW JOURNAL OF PHYSICS
(2023)
Article
Physics, Multidisciplinary
Mikolaj Lasota, Olena Kovalenko, Vladyslav C. Usenko
Summary: Discrete-variable (DV) and continuous-variable (CV) schemes are the two major families of quantum key distribution (QKD) protocols. This work compares the major entanglement-based DV and CV QKD protocols in terms of their resistance to channel noise, and finds the definite superiority of the DV family. The influence of DV QKD setup imperfections on the obtained results is also investigated.
NEW JOURNAL OF PHYSICS
(2023)
Article
Quantum Science & Technology
Adnan A. E. Hajomer, Nitin Jain, Hossein Mani, Hou-Man Chin, Ulrik L. Andersen, Tobias Gehring
Summary: This study proposes a CVQKD system without modulation leakage vulnerability, achieving state preparation and measurement using baseband modulation and an IQ modulator. The system can generate a composable secret key secure against collective attacks.
NPJ QUANTUM INFORMATION
(2022)
Article
Optics
Eneet Kaur, Saikat Guha, Mark M. Wilde
Summary: This study explores security proofs and achievable secret-key rates for discrete-modulation protocols in CV-QKD. The approach involves approximating a Gaussian probability distribution, applying entropic continuity bounds, and leveraging previous security proofs. In lossy thermal bosonic channels, the achievable secret-key rates for discrete-modulation protocols approach those of Gaussian-modulation protocols as the constellation size increases.
Article
Physics, Multidisciplinary
Yiwu Zhu, Lei Mao, Hui Hu, Yijun Wang
Summary: This study investigates the effects of oceanic turbulence on the performance of continuous variable quantum key distribution (CVQKD) systems and proposes the feasibility of passive CVQKD through oceanic turbulence-based channels. The channel transmittance, characterized by the transmission distance and depth of seawater, is achieved. Non-Gaussian approaches are used to improve performance by countering excess noise effects on the oceanic channel. Numerical simulations demonstrate that the photon operation (PO) unit reduces excess noise and improves performance in terms of transmission distance and depth when considering oceanic turbulence. The passive CVQKD, which exploits the intrinsic field fluctuations of a thermal source without an active scheme, has promising applications in chip integration for portable quantum communications.
