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We consider the security of continuous-variable quantum key distribution using thermal (or noisy) Gaussian resource states. Specifically, we analyze this against collective Gaussian attacks using direct and reverse reconciliation where both…

Quantum Physics · Physics 2013-04-17 Christian Weedbrook , Stefano Pirandola , Timothy C. Ralph

Continuous-variable (CV) quantum key distribution (QKD) allows for quantum secure communication with the benefit of being close to existing classical coherent communication. In recent years, CV QKD protocols using a discrete number of…

Parameter estimation is a critical step in continuous-variable quantum key distribution (CV-QKD), especially in the finite-size regime where worst-case confidence intervals can significantly reduce the achievable secret-key rate. We provide…

We report the first continuous-variable quantum key distribution experiment that enables the generation of secure key over a 60 km fiber channel with locally generated local oscillator. This is achieved by controlling the excess noise using…

We developed a one-way quantum key distribution (QKD) system based upon a planar lightwave circuit (PLC) interferometer. This interferometer is expected to be free from the backscattering inherent in commercially available two-way QKD…

Quantum Physics · Physics 2009-11-13 Yoshihiro Nambu , Ken'ichiro Yoshino , Akihisa Tomita

To improve the performance of a quantum key distribution (QKD) system, high speed, low dark count single photon detectors (or low noise homodyne detectors) are required. However, in practice, a fast detector is usually noisy. Here, we…

Quantum Physics · Physics 2009-11-13 Bing Qi , Yi Zhao , Xiongfeng Ma , Hoi-Kwong Lo , Li Qian

A noiseless linear amplifier (NLA) performs the highest quality amplification allowable under the rules of quantum physics. Unfortunately, these same rules conspire against us via the no-cloning theorem, which constrains NLA operations to…

Quantum Physics · Physics 2023-10-27 Joshua J. Guanzon , Matthew S. Winnel , Deepesh Singh , Austin P. Lund , Timothy C. Ralph

We present a practical method that can make quantum key distribution (QKD), for the first time, both ultra-long-distance and immune to all attacks in the detection system. This method is an important extension of the…

Quantum Physics · Physics 2013-08-22 Feihu Xu , Bing Qi , Zhongfa Liao , Hoi-Kwong Lo

In recent years, continuous-variable quantum key distribution (CV-QKD) has become a promising paradigm for enabling secure communication among multiple end users sharing the same telecommunication backbone. CV-QKD with reverse…

Proposed in 1984, quantum key distribution (QKD) allows two users to exchange provably secure keys via a potentially insecure quantum channel. Since then, QKD has attracted much attention and significant progress has been made in both…

We propose an efficient logical layer-based reconciliation method for continuous-variable quantum key distribution (CVQKD) to extract binary information from correlated Gaussian variables. We demonstrate that by operating on the raw-data…

Quantum Physics · Physics 2018-01-09 Laszlo Gyongyosi , Sandor Imre

We consider two remote parties connected to a relay by two quantum channels. To generate a secret key, they transmit coherent states to the relay, where the states are subject to a continuous-variable (CV) Bell detection. We study the ideal…

We use single homodyne detector to accomplish Continuous-Variable quantum key distribution(CV QKD) in a laboratory and urban environment free-space channel. This is based on Gaussian modulation with coherent-states in the polarization…

Quantum Physics · Physics 2019-07-24 Shi-Yang Shen , Ming-Wei Dai , Xue-Tao Zheng , Qi-Yao Sun , Bing Zhu , Guang-Can Guo , Zheng-Fu Han

As quantum key distribution (QKD) emerges as a robust defense against quantum computer threats, significant advancements have been realized by researchers. A pivotal focus has been the development of protocols that not only simplify…

Multi-carrier continuous-variable quantum key distribution (CV-QKD) is considered to be a promising way to boost the secret key rate (SKR) over the existing single-carrier CV-QKD scheme. However, the extra excess noise induced in the…

Quantum Physics · Physics 2023-03-22 Heng Wang , Yan Pan , Yun Shao , Yaodi Pi , Ting Ye , Yang Li , Tao Zhang , Jinlu Liu , Jie Yang , Li Ma , Wei Huang , Bingjie Xu

Excess noise is a major obstacle to high-performance continuous-variable quantum key distribution (CVQKD), which is mainly derived from the amplitude attenuation and phase fluctuation of quantum signals caused by channel instability. Here,…

Quantum Physics · Physics 2022-07-22 Kexin Liang , Geng Chai , Zhengwen Cao , Qing Wang , Lei Wang , Jinye Peng

Quantum key distribution (QKD) permits information-theoretically secure transmission of digital encryption keys, assuming that the behaviour of the devices employed for the key exchange can be reliably modelled and predicted. Remarkably, no…

Continuous-variable quantum key distribution (CV-QKD) has emerged as a promising approach for secure quantum communication, offering advantages such as high key generation rates, compatibility with standard telecommunication infrastructure,…

We present a rigorous security analysis of Continuous-Variable Measurement-Device Independent Quantum Key Distribution (CV MDI QKD) in a finite size scenario. The security proof is obtained in two steps: by first assessing the security…

Quantum Physics · Physics 2018-06-12 Cosmo Lupo , Carlo Ottaviani , Panagiotis Papanastasiou , Stefano Pirandola

Twin-field quantum key distribution (TF-QKD) overcomes the linear rate-loss limit, which promises a boost of secure key rate over long distance. However, the complexity of eliminating the frequency differences between the independent laser…