Article
Optics
Yan Tian, Pu Wang, Jianqiang Liu, Shanna Du, Wenyuan Liu, Zhenguo Lu, Xuyang Wang, Yongmin Li
Summary: Measurement-device-independent quantum key distribution (MDI-QKD) can eliminate all side-channel attacks on detectors. This research successfully demonstrated continuous-variable MDI-QKD over optical fiber and proved its feasibility in practical applications.
Article
Optics
Yan Tian, Yu Zhang, Shuaishuai Liu, Pu Wang, Zhenguo Lu, Xuyang Wang, Yongmin Li
Summary: We demonstrate the successful implementation of a high-rate discretely modulated continuous-variable quantum key distribution system over 80 km standard single-mode fiber. By using well-designed digital signal processing algorithms, we effectively suppress the excess noise of the system. The achieved secret key rates are 49.02 Mbits/s, 11.86 Mbits/s, and 2.11 Mbits/s over 25 km, 50 km, and 80 km optical fiber, respectively, which are 67.4%, 70.0%, and 66.5% of the secret key rate performance of a Gaussian-modulated protocol.
Article
Optics
Yan Pan, Heng Wang, Yun Shao, Yaodi Pi, Yang Li, Bin Liu, Wei Huang, Bingjie Xu
Summary: A high-rate continuous-variable quantum key distribution (CV-QKD) system based on high-order discrete modulation is experimentally investigated. The results demonstrate the potential application of the high-rate discrete-modulated CV-QKD system for high-speed security communication under tens of kilometers, achieving transmission results and secret key rates comparable to ideal Gaussian modulation.
Article
Optics
Zikang Su, Jintao Wang, Dajian Cai, Xiaojie Guo, Dawei Wang, Zhaohui Li
Summary: We propose and experimentally demonstrate a phase-sensitive continuous variable quantum key distribution system with improved secure key rate, utilizing multimode coherent states, phase-conjugated subcarrier modulation, and phase-sensitive detection. The experimental results confirm the higher secure key rate and better excess noise tolerance of the new scheme compared to the typical implementation of GG02.
PHOTONICS RESEARCH
(2023)
Article
Engineering, Electrical & Electronic
Tao Shen, Xiangyu Wang, Ziyang Chen, Huiping Tian, Song Yu, Hong Guo
Summary: The compensation process for the state of polarization (SOP) from quantum signal is crucial for practical implementation of CV-QKD. Instead of using an expensive digital dynamic polarization controller, this study utilizes a cheaper manual polarization controller and a digital algorithm based on Kalman filter to achieve polarization loss compensation when the SOP of the fiber is relatively stable. Other digital signal processing methods are also discussed for final secret key rate. Experimental results show that this polarization loss compensation method maintains the stability of the final secret key rate and achieves a secret key rate of 110 kbps within 20 km optical fiber (with 4 dB loss) under finite-size block of 1 x 10(6) over an extended time in the laboratory.
IEEE PHOTONICS JOURNAL
(2023)
Article
Physics, Multidisciplinary
Peng Huang, Tao Wang, Rui Chen, Ping Wang, Yingming Zhou, Guihua Zeng
Summary: This paper discusses the experimental implementation of Gaussian-modulated coherent-state continuous-variable quantum key distribution protocol using passive-state preparation method to generate secure keys in realistic optical fiber channels. By controlling excess noise and establishing correlation between data, the issues of finite-size effects and Gaussian attacks are successfully addressed.
NEW JOURNAL OF PHYSICS
(2021)
Article
Optics
Xiangyu Wang, Ziyang Chen, Zhenghua LI, Dengke Qi, Song Yu, Hong Guo
Summary: This research demonstrates the potential of continuous variable quantum key distribution in practical quantum access networks. A two-end-user network with a secret key rate of 390 kbits/s is achieved through technical upgrades. The network capacity in the case of multiple users is also analyzed.
Article
Optics
Yaodi Pi, Heng Wang, Yan Pan, Yun Shao, Yang Li, Jie Yang, Yichen Zhang, Wei Huang, Bingjie Xu
Summary: We demonstrated a sub-Mbps Gaussian-modulated coherent-state continuous-variable quantum key distribution system over a 100-km transmission distance. To control excess noise, the quantum signal and the pilot tone were co-transmitted in the fiber channel using wideband frequency and polarization multiplexing methods. A high-accuracy data-assisted time domain equalization algorithm was designed to compensate for phase noise and polarization variation. The experimentally calculated secure key rate over transmission distances of 50 km, 75 km, and 100 km was 7.55 Mbps, 1.87 Mbps, and 0.51 Mbps, respectively. This experiment significantly improved the transmission distance and secure key rate compared to previous state-of-the-art results, demonstrating the potential for long-distance and high-speed secure quantum key distribution.
Article
Optics
Mingqi Zhang, Peng Huang, Ping Wang, Shurong Wei, Guihua Zeng
Summary: The passive-state-preparation (PSP) continuous-variable quantum key distribution (CVQKD) protocol exploits the inherent field fluctuations of a thermal source. It does not require active modulations, making it promising for chip integration and portable free-space quantum key distribution.
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
Optics
Min Wei, Chun-Hui Zhang, Jian Li, Jia-Li Zhu, Qin Wang
Summary: Tomography is a beneficial technique in quantum information and quantum optics, and in this study, the authors conducted the first experimental demonstration of tomography-based quantum key distribution (TB-QKD). They compared it with reference-frame-independent QKD (RFI-QKD) and showed that TB-QKD outperformed RFI-QKD in certain channels.
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
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
Multidisciplinary Sciences
William P. Livingston, Machiel S. Blok, Emmanuel Flurin, Justin Dressel, Andrew N. Jordan, Irfan Siddiqi
Summary: Continuous quantum error correction using direct parity measurements in a resource-efficient manner is demonstrated, achieving high detection efficiency and increasing the relaxation time of protected logical qubits.
NATURE COMMUNICATIONS
(2022)
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
Physics, Mathematical
Anthony Leverrier
JOURNAL OF MATHEMATICAL PHYSICS
(2018)
Editorial Material
Optics
Mohsen Razavi, Anthony Leverrier, Xiongfeng Ma, Bing Qi, Zhiliang Yuan
JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS
(2019)
Article
Physics, Multidisciplinary
Shouvik Ghorai, Philippe Grangier, Eleni Diamanti, Anthony Leverrier
Article
Computer Science, Hardware & Architecture
Omar Fawzi, Antoine Grospellier, Anthony Leverrier
Summary: The paper investigates the asymptotic scaling of space overhead required for fault-tolerant quantum computation, showing that the polylogarithmic factor in the standard threshold theorem is unnecessary. A fault-tolerant construction is proposed that only uses a constant factor more qubits than the ideal computation. This result challenges the traditional concatenated code approach and suggests using quantum error-correcting codes with a constant encoding rate.
COMMUNICATIONS OF THE ACM
(2021)
Article
Quantum Science & Technology
Daniele Dequal, Luis Trigo Vidarte, Victor Roman Rodriguez, Giuseppe Vallone, Paolo Villoresi, Anthony Leverrier, Eleni Diamanti
Summary: Establishing secure communication links at a global scale using quantum information science is challenging but achievable, as shown by recent landmark experiments. Continuous-variable encoding in a satellite-to-ground downlink configuration can lead to positive secret key rates, especially in low-Earth-orbit scenarios, with limitations potentially arising in higher orbits due to finite-size effects. Our analysis helps determine parameters for successful secret key exchange and can guide further experimental efforts in this direction.
NPJ QUANTUM INFORMATION
(2021)
Article
Quantum Science & Technology
Antoine Grospellier, Lucien Groues, Anirudh Krishna, Anthony Leverrier
Summary: This research introduces new hybrid decoders that combine the belief propagation algorithm with the small-set-flip (SSF) decoder to improve the decoding performance of quantum low-density parity-check (LDPC) codes. Numerical simulations show that the error threshold of these codes performs well under different conditions.
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
Quantum Science & Technology
Anthony Leverrier, Simon Apers, Christophe Vuillot
Summary: This article introduces a variant of the three-dimensional hypergraph product code construction and explores the non-CSS quantum LDPC code and its related algebraic and combinatorial problems, aiming to find potential codes for self-correcting quantum memories.
Article
Quantum Science & Technology
Anthony Leverrier, Vivien Londe, Gilles Zemor
Summary: This study introduces a new family of quantum codes called hemicubic codes. These codes are obtained by associating qubits with the faces of the n-cube and stabilizer constraints with faces of dimension (p +/- 1). The resulting quantum codes display local testability and a decoding algorithm is developed to correct errors. The study also explores the extension of this code family by considering the quotient of the n-cube by arbitrary linear classical codes. These hemicubic codes have potential applications in quantum computing.
Proceedings Paper
Computer Science, Information Systems
Omar Fawzi, Lucien Groues, Anthony Leverrier
Summary: The decoder based on linear programming for quantum CSS codes has a different approach from previous definitions, but performs well in simulations, especially in hypergraph products, where it outperforms traditional methods.
2020 IEEE INFORMATION THEORY WORKSHOP (ITW)
(2021)
Article
Computer Science, Theory & Methods
Vivien Londe, Anthony Leverrier
QUANTUM INFORMATION & COMPUTATION
(2019)
Article
Optics
Shouvik Ghorai, Eleni Diamanti, Anthony Leverrier
Proceedings Paper
Computer Science, Theory & Methods
Omar Fawzi, Antoine Grospellier, Anthony Leverrier
STOC'18: PROCEEDINGS OF THE 50TH ANNUAL ACM SIGACT SYMPOSIUM ON THEORY OF COMPUTING
(2018)
Proceedings Paper
Computer Science, Theory & Methods
Omar Fawzi, Antoine Grospellier, Anthony Leverrier
2018 IEEE 59TH ANNUAL SYMPOSIUM ON FOUNDATIONS OF COMPUTER SCIENCE (FOCS)
(2018)
Article
Quantum Science & Technology
Marco Tomamichel, Anthony Leverrier