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Future global quantum communication networks, or quantum Internet, will realize high-rate secure communication and entanglement distribution for large-scale users over long distances. Continuous variable (CV) quantum key distribution (QKD)…

Quantum Physics · Physics 2026-02-26 Zhiyue Zuo , Masoud Ghalaii , Stefano Pirandola

We propose a continuous variable quantum key distribution protocol based on discrete modulation of eight-state coherent states. We present a rigorous security proof against the collective attacks considering both of realistic lossy, noisy…

Quantum Physics · Physics 2010-06-23 A. Becir , F. A. A. El-Orany , M. R. B. Wahiddin

Quantum key distribution(QKD) might be the most famous application of quantum information theory. The idea of QKD is not difficult to understand but in practical implementations, many problems are needed to be solved, for example, the noise…

Quantum Physics · Physics 2023-08-01 Hao Shu , Chang-Yue Zhang , Yue-Qiu Chen , Zhu-Jun Zheng , Shao-Ming Fei

Continuous-variable quantum key distribution (CVQKD) has potential advantages of high secret key rate, which is very suitable for high-speed metropolitan network application. However, the reported highest secret key rates of the CVQKD…

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

In this paper, we investigate and assess the performance of intra-channel nonlinearity compensation (IC-NLC) in long-haul coherent optical transmission systems with a symbol rate of 200 GBaud and beyond. We first evaluate the potential gain…

Optics · Physics 2025-07-29 Zhiyuan Yang , Mengfan Fu , Yihao Zhang , Qizhi Qiu , Lilin Yi , Weisheng Hu , Qunbi Zhuge

We propose a frequency-division multiplexed (FDM) continuous-variable quantum key distribution (CV-QKD) system with enhanced spectral efficiency through dense multiplexing of low-symbol-rate signals. A four-channel 10-Mbaud FDM-CV-QKD…

Quantum Physics · Physics 2026-03-24 Jahyeok Han , Donghyeok Le , Minseok Ryu , Syed Assad , Yong-Su Kim , Sunghyun Bae

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…

Many different quantum information communication protocols such as teleportation, dense coding and entanglement based quantum key distribution are based on the faithful transmission of entanglement between distant location in an optical…

We propose the Gaussian continuous-variable quantum key distribution using squeezed states in the composite channels including atmospheric propagation with transmittance fluctuations. We show that adjustments of signal modulation and use of…

Quantum Physics · Physics 2023-12-05 Ivan Derkach , Vladyslav C. Usenko , Radim Filip

A Low-Power Variable Gain (VG) mm-Wave Low Noise Amplifier (LNA) is designed and simulated in a 28-nm CMOS process. The LNA utilizes a simple, yet novel, technique presented in this paper to vary the small-signal output resistance to…

Signal Processing · Electrical Eng. & Systems 2025-12-02 Harshith Reddy , Pankaj Arora

Real-time CV-QKD receiver achieves peak 2.9 Mbit/s secret-key-rates over 12.8 km of fiber, while co-propagating 15 classical channels, separated 1 nm from the quantum signal. Performance degrades at higher launch powers due to crosstalk.

We study the operational regime of a noiseless linear amplifier based on quantum scissors that can nondeterministically amplify the one photon component of a quantum state with weak excitation. It has been shown that an arbitrarily large…

Quantum Physics · Physics 2014-11-04 J. Bernu , S. Armstrong , T. Symul , T. C. Ralph , P. K. Lam

Gaussian channel simulation is an essential paradigm in understanding the evolution of bosonic quantum states. It allows us to investigate how such states are influenced by the environment and how they transmit quantum information. This…

Theoretical results are presented which show that noiseless phase quadrature amplification is possible, and limited experimentally only by the efficiency of the phase detection system. Experimental results obtained using a Nd:YAG laser show…

Quantum Physics · Physics 2009-10-31 Ben C. Buchler , Elanor H. Huntington , Timothy C. Ralph

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

It is known that quantum scissors, as non-deterministic amplifiers, can enhance the performance of Gaussian-modulated continuous-variable quantum key distribution (CV-QKD) in noisy and long-distance regimes of operation. Here, we extend…

Quantum Physics · Physics 2020-04-06 Masoud Ghalaii , Carlo Ottaviani , Rupesh Kumar , Stefano Pirandola , Mohsen Razavi

In the Gaussian-modulated coherent state quantum key distribution (QKD) protocol, the sender first generates Gaussian distributed random numbers and then encodes them on weak laser pulses actively by performing amplitude and phase…

Heralded noiseless amplification based on single-photon sources and linear optics is ideally suited for long-distance quantum communication tasks based on discrete variables. We experimentally demonstrate such an amplifier, operating at…

Quantum Physics · Physics 2013-02-28 C. I. Osorio , N. Bruno , N. Sangouard , H. Zbinden , N. Gisin , R. T. Thew

The advent of quantum computers has significantly challenged the security of traditional cryptographic systems, prompting a surge in research on quantum key distribution (QKD). Among various QKD approaches, continuous-variable QKD (CVQKD)…

Quantum Physics · Physics 2025-03-26 Xiaojuan Liao , Yuehan Xu , Qijun Zhang , Peng Huang , Tao Wang , Kaizhi Wang , Guihua Zeng

The use of quantum scissors, as candidates for non-deterministic amplifiers, in continuous-variable quantum key distribution systems is investigated. Such devices rely on single-photon sources for their operation and as such, they do not…

Quantum Physics · Physics 2020-07-16 Masoud Ghalaii , Carlo Ottaviani , Rupesh Kumar , Stefano Pirandola , Mohsen Razavi