Variational Estimation of Optimal Signal States for Quantum Channels by Leonardo Oleynik, Junaid Ur Rehman, Hayder Al-Hraishawi, Symeon Chatzinotas

“…Instead of theoretically bounding the ultimate capacity of the channel, we adopt a signal processing perspective to estimate the achievable performance of a physically available but otherwise unknown quantum channel. …”
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Breaking fundamental limits of quantum entanglement distribution with quantum switch by XU Ruiqing, ZHOU Rigui, LI Yaochong

“…Then the tighter upper bound of channel capacity was derived by using teleportation simulation of quantum channel, the tighter lower bound was derived on the basis of Hash inequality. …”
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Channel capacity analysis of non-line-of-sight ultraviolet communication in noncoplanar geometry based on traversing tiny unit method by Peng SONG, Caixia SU, Taifei ZHAO, Jinni CHEN, Lei ZHU, Xiaodan ZHANG

“…Channel capacity reflects the ability of the system to transmit information without errors.The path loss and impulse response of the system were calculated based on traversing tiny unit method,and then the frequency response of the system was obtained by the discrete Fourier transform of the impulse response sampling sequence,and the 3 dB bandwidth of the system was calculated.Considering the shot noise caused by signal light,the signal-to-noise ratio of the system was obtained according to the quantum limit method,and then the relationship between the channel capacity and the geometric parameters of transmitter and receiver in non-line-of-sight noncoplanar ultraviolet communication system were simulated and analyzed by Shannon formula.The results show that the channel capacity decreases with the increase of the off axis angle and the communication distance.When the elevation angles of transmitter and receiver are less than 40°,the channel capacity decreases rapidly with the increase of the elevation angles of transmitter and receiver,and the transmitter elevation angle has a great influence on the channel capacity.The system channel capacity is almost constant with the increase of divergence angle,and the larger the receiver field of view angle,the greater the system channel capacity.…”
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Influence of thunderstorm cloud on the performance of satellite-to-ground quantum link and parameters simulation by Min NIE, Li SHI, Guang YANG, Chang-xing PEI

“…In order to investigate the effect of thunderstorm cloud on the performance of satellite-to-ground quantum link,according to the extinction cross section and the number concentration distribution function of the charged particle in the thunderstorm cloud,the relationships among the particle concentration,charge density and link attenuation of charged particles in atmosphere were established.The relationship between the atmospheric concentration of charged particles,the charge density on the average channel capacity,channel fidelity,channel survival function and bit error rate of quantum key distribution system were put out.The simulation results show that the thunderstorm cloud has a significant effect on the performance of the satellite-to-ground quantum link.So in order to improve the reliability of satellite-ground quantum communication,the system parameters should be adjusted according to the forecast of the thunderstorm cloud.…”
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Quantum public-key encryption protocol based on single-photon by Wen-jun LUO, Guan-li LIU

“…A quantum public-key encryption protocol based on single-photon was provided.Pseudo random sequence mapping to private keys to implement corresponding quantum operations and then obtaining quantum public-key to encode the plaintext was used.Employ the method of block classification to lower the requirement for storage capacity of the sender.A new quantum source as transmission carrier was introduced and simply encoding and decoding rules were designed based on the laws of quantum non-cloning and ciphertext indistinguishability.On the other hand,classical one-time pad technique is used to ensure the security of quantum key and plaintext in the transmission channel.At the same time,select different updating strategy of quantum public-key according to the results of error detection which can significantly reduce key consumption.Compared with the previous quantum public-key encryption based on entangled states and single-photon,there are no entangled states and decoyed particles are needed,so it is not only efficient to reduce the overhead of communication traffic between legitimate users,but also easier to carry out in practice.The analysis shows that the proposed scheme is secure.…”
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Multi-pulse Fourier codes for bit transmission at the quantum limit by Matteo Rosati

“…Bit-transmission can be enhanced by the use of quantum detection techniques, realizing a joint-detection receiver (JDR) that is able to decode transmitted signals via a collective operation and achieve the Holevo channel capacity. …”
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Noise suppression in the co-propagation of quantum signals and classical optical signals by Yongmei SUN, Jianing NIU, Yuefeng JI

“…At present,the technologies of device and system required for the fiber-based point-to-point quantum key distribution (QKD) are gradually becoming mature and showing the trend of commercial application.Therefore,how to multiplex quantum signals and classical optical signals in a single fiber to greatly increase the capacity and save fiber resources has been becoming one of the hotspots of academia in recent years.The noise impairments in the co-propagation of quantum signals and classical optical signals over a single fiber were mainly studied.Firstly,the influences of the main noises,four-wave mixing (FWM) and Raman scattering on the quantum channels were analyzed.Next,an unequal-frequency-spacing-based FWM noise suppression algorithm and a wavelength assignment algorithm for joint suppression of FWM and Raman scattering were proposed for different application scenarios with different channel space and transmission distance.Finally,the superiorities of the proposed algorithms were verified through numerical simulations.The research results provide feasible noise suppression schemes for different application scenarios in the future.…”
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Quantum key distribution implemented with d-level time-bin entangled photons by Hao Yu, Stefania Sciara, Mario Chemnitz, Nicola Montaut, Benjamin Crockett, Bennet Fischer, Robin Helsten, Benjamin Wetzel, Thorsten A. Goebel, Ria G. Krämer, Brent E. Little, Sai T. Chu, Stefan Nolte, Zhiming Wang, José Azaña, William J. Munro, David J. Moss, Roberto Morandotti

“…Our approach enables the manipulation of time-bin entangled qudits at processing speeds typical of standard telecommunications (10 s of GHz) with high quantum information capacity per single frequency channel, representing an important step towards an efficient implementation of high-data rate quantum communications in standard, multi-user optical fiber networks.…”
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Fault-Tolerant One-Way Noiseless Amplification for Microwave Bosonic Quantum Information Processing by Hany Khalifa, Riku Jantti, Gheorghe Sorin Paraoanu

“…Microwave quantum information networks require reliable transmission of single-photon propagating modes over lossy channels. …”
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New dimension in vortex electro-magnetic wave transmission with orbital angular momentum by Chao ZHANG, Yuanhe WANG

“…Consequence:In order to illustrate the application scope and the outstanding advantages utilized by quantum OAM electromagnetic waves and statistical OAM Beams, this paper classifies the typical OAM transmission systems into four regions based on channel capacity.From the high channel capacity to the low channel capacity, Region A belongs to the quantum OAM transmission system with the new dimension of OAM, using vortex microwave photon to convey information, and the corresponding capacity bound can be enhanced to surpass the traditional multi-antenna MIMO capacity bound;Regions B,C and D belong to the statistical OAM vortex beams,which do not own new dimensions in MIMO transmission but have outstanding performance in the Line-of-Sight (LoS) channel. …”
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Heralded interconversion between hyperentangled W state and hyperentangled KLM state assisted by nitrogen vacancy centers coupled with microresonators by Fang-Fang Du, Ming Ma, Qiu-lin Tan

“…Abstract As the hyperentanglement of photon systems holds lots of remarkable applications for enhancing channel capacity with less quantum resource, the interconversion of various hyperentangled states warrants in-depth investigation and becomes a vital work for quantum information technologies. …”
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Renormalized Phonon Microstructures at High Temperatures from First-Principles Calculations: Methodologies and Applications in Studying Strong Anharmonic Vibrations of Solids by Tian Lan, Zhaoyan Zhu

“…The review aims to introduce some recent developements of computational methodologies that are able to efficiently model the strong phonon anharmonicity based on quantum perturbation theory of many-body interactions and first-principles molecular dynamics simulations. …”
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