Article
Optics
Duo-Lun Chen, Zhou-Quan Zhou, Chuan-Feng Li, Guang-Can Guo
Summary: The paper proposes a DLCZ-like scheme based on noiseless photon echo in rare-earth ion-doped crystals to establish remote entanglements and realize large-scale quantum networks. By directly rephasing the optics, correlated photon pairs with controllable delay can be created. Theoretical analysis shows that the protocol is efficient in the low-optical-depth regime. This protocol could be feasibly implemented to establish long-lived quantum correlations between a photon and a spin-wave excitation in rare-earth ion-doped crystals.
Article
Quantum Science & Technology
Athena Karsa, Masoud Ghalaii, Stefano Pirandola
Summary: Quantum target detection aims to achieve performances not possible through classical means by utilizing quantum technologies. This paper investigates the use of a noiseless linear amplifier in the detection stage of a quantum illumination-based protocol, and derives the quantum Chernoff bound to analyze the detection error probability. The findings show that the potential quantum advantage is amplified in this scheme, extending the potential use of quantum illumination.
QUANTUM SCIENCE AND TECHNOLOGY
(2022)
Article
Optics
Mingjian He, Robert Malaney, Benjamin A. Burnett
Summary: This work investigates the use of entanglement structure to enhance multi-party quantum information applications, introducing a novel noiseless linear amplifier, the PC-NLA, and combining it with the QS-NLA. The impact of multimode entanglement on amplifier performance is studied, revealing that a multimode NLA is effective only beyond a certain threshold depending on the structure.
Article
Quantum Science & Technology
Peter E. Frenkel, Mihaly Weiner
Summary: Classical channels cannot increase their capacity or the sum of conditional probabilities for successful transmission through the use of shared entanglement or non-signaling resources. However, entanglement can still assist and enhance the chances of success in a one-way communication task using a noiseless classical channel. Researchers have found that if the resource is a bipartite quantum system in a maximally entangled state, an extra classical bit is always sufficient as a replacement.
Article
Physics, Multidisciplinary
Shicheng Zhang, Yifan Zhan, Shangqing Gong, Yueping Niu
Summary: In this article, the author proposes a noiseless single-photon isolator scheme in theory and demonstrates it experimentally using hot atoms.
COMMUNICATIONS PHYSICS
(2023)
Article
Engineering, Civil
Moaaz Ahmed, Muhammad Asim Atta, James Farmer, Zaher Dawy, Dominic O'Brien, Amine Bermak
Summary: This paper discusses various techniques to suppress ambient light interference in visible light communication systems, particularly focusing on VLC systems for vehicular communication. The study addresses the challenges of designing transceivers for outdoor VLC systems in dynamic environments with interference from different types of ambient light sources. It offers qualitative insights by considering multiple physical domains to tackle the issue of optical interference.
IEEE TRANSACTIONS ON INTELLIGENT TRANSPORTATION SYSTEMS
(2022)
Article
Engineering, Electrical & Electronic
Hiroto Kawakami, Takayuki Kobayashi, Yoshiaki Kisaka
Summary: In this paper, the authors discuss the beat-noise induced by a distributed Raman amplifier system with forward pumping and propose a technique to suppress it. They show that depolarization and suppression of pump light intensity noise are necessary techniques to construct a Raman amplifier. The authors also present experimental results demonstrating the advantages of their proposed noise suppression technique in optical data transmission.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2023)
Article
Quantum Science & Technology
Marco Pistoia, Omar Amer, Monik R. Behera, Joseph A. Dolphin, James F. Dynes, Benny John, Paul A. Haigh, Yasushi Kawakura, David H. Kramer, Jeffrey Lyon, Navid Moazzami, Tulasi D. Movva, Antigoni Polychroniadou, Suresh Shetty, Greg Sysak, Farzam Toudeh-Fallah, Sudhir Upadhyay, Robert Woodward, Andrew J. Shields
Summary: This article presents experimental research on implementing high-capacity quantum-secured optical channels in mission-critical metro-scale operational environments using quantum key distribution (QKD) technology. The study achieved an 800 Gbps quantum-secured optical channel, multiplexed with other dense wavelength division multiplexed channels, on distances up to 100 km. The research also demonstrated the secure transportation of a blockchain application over the established channel. These findings contribute to the deployment of QKD-secured optical channels in high-capacity, metro-scale, mission-critical operational environments.
QUANTUM SCIENCE AND TECHNOLOGY
(2023)
Article
Optics
Ke Di, Shuai Tan, Liyong Wang, Anyu Cheng, Xi Wang, Yuming Sun, Junqi Guo, Yu Liu, Jiajia Du
Summary: This paper investigates quantum noise suppression and phase-sensitive modulation for continuous variable of vacuum and squeezed fields in a hybrid resonant cavity system. Multiple dark windows similar to electromagnetic induction transparency (EIT) are observed in the quantum noise fluctuation curve. The effects of pumping light on both quantum noise suppression and controlling the widths of dark windows are analyzed, and the saturation point of pumping light for nonlinear crystal conversion is obtained. The results show that the noise suppression effect is highly sensitive to the pumping light power, with a degree of noise suppression up to 13.9 dB at a pumping light power of 0.65 & beta;th. Furthermore, a phase-sensitive modulation scheme is demonstrated, which addresses the challenge of multi-channel quantum noise suppression in the quadrature amplitude of squeezed field.
OPTICS AND LASER TECHNOLOGY
(2023)
Article
Engineering, Electrical & Electronic
Janis Noetzel, Matteo Rosati
Summary: This article examines all-optical networks from a quantum perspective and demonstrates the benefits of using quantum receivers in terms of energy consumption reduction and increased system capacity. Based on these findings, the article proposes a new approach to optical communication network design.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2023)
Article
Quantum Science & Technology
Yang Liu, Kaimin Zheng, Haijun Kang, Dongmei Han, Meihong Wang, Lijian Zhang, Xiaolong Su, Kunchi Peng
Summary: This study experimentally demonstrates the distillation of Gaussian EPR steering and entanglement in lossy and noisy environments, and discovers the phenomenon of an extended steerable region in the distillation of EPR steering, which is different from entanglement distillation.
NPJ QUANTUM INFORMATION
(2022)
Article
Chemistry, Multidisciplinary
Nima Taghipour, Guy L. Whitworth, Andreas Othonos, Mariona Dalmases, Santanu Pradhan, Yongjie Wang, Gaurav Kumar, Gerasimos Konstantatos
Summary: A binary blend of CQDs and ZnO nanocrystals is used to passivate trap states in PbS-CQD gain medium, leading to improved Auger lifetime and suppression of trap-assisted Auger recombination. Integration of this binary blend with a DFB resonator has demonstrated stable single-mode lasing emission with low threshold and continuous operation of 5 hours under room temperature and ambient conditions.
ADVANCED MATERIALS
(2022)
Article
Optics
Jeffrey H. Shapiro
Summary: This research proves that the error probability of a coherent-state radar is within a factor of two of the best possible quantum performance under certain conditions. However, first-photon radars can surpass this limit and achieve better performance.
Article
Optics
Vinod N. Rao, R. Srikanth
Summary: Counterfactual quantum key distribution protocols can be made more efficient by including noncounterfactual bits, potentially leading to noiseless attacks. Counterfactual security can enhance key rate without compromising security in various existing protocols.
Article
Engineering, Electrical & Electronic
Hiroto Kawakami, Shoichiro Kuwahara, Yoshiaki Kisaka
Summary: This study investigates random intensity noises in forward-pumped distributed Raman amplifier systems, showing characteristics of pump-to-signal intensity noise transfer and proposing solutions for noise induced in pump light. A novel optical depolarizer for pump light is introduced to manage optical phases and suppress gain instability. Measurement results demonstrate improved 16-QAM transmission specifications with acceptable noise levels during operation.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2021)
Article
Physics, Multidisciplinary
Josef Hlousek, Miroslav Jezek, Jaromir Fiurasek
Summary: This paper proposes and experimentally demonstrates a method for directly certifying the non-Gaussianity and Wigner function negativity of photonic quantum detectors, using only two classical thermal states and a vacuum state for probing. The results show the feasibility of benchmarking photonic quantum detectors with a few measurements on classical states.
PHYSICAL REVIEW LETTERS
(2021)
Article
Optics
Martin Bielak, Robert Starek, Vojtech Krcmarsky, Michal Micuda, Miroslav Jezek
Summary: Liquid crystal devices are essential in optical metrology, optical communications, polarization-sensitive imaging, and photonic information processing, and can achieve fast preparation and detection of polarization states with unprecedented accuracy.
Article
Optics
Jaromir Fiurasek
Summary: We propose and theoretically analyze a teleportation-based scheme for the high-fidelity noiseless quantum amplification of coherent states of light. In this scheme, the probabilistic noiseless quantum amplification operation is encoded into a suitable auxiliary two-mode entangled state and then applied to the input coherent state via continuous-variable quantum teleportation. This scheme requires conditioning on the outcomes of homodyne measurements in the teleportation protocol. Compared to existing high-fidelity noiseless quantum amplifiers, this scheme only requires photon subtraction combined with auxiliary Gaussian squeezed vacuum states. The paper provides a pure-state description of the protocol and a comprehensive model based on phase-space representation, taking into account experimental imperfections.
Article
Instruments & Instrumentation
Glib Mazin, Ales Stejskal, Michal Dudka, Miroslav Jezek
Summary: The non-blocking high-resolution digital delay line based on asynchronous circuit design allows for an efficient trade-off between resolution and delay range, with minimized dead time operation. Experimental characterization revealed linear dependence of delay on temperature, increasing timing jitter over the delay dynamic range, and the use of pulse shrinking circuits to reduce pulse spreading effect. This delay line is suitable for applications requiring dead time minimization and acceptable excess jitter in advanced photonic networks.
REVIEW OF SCIENTIFIC INSTRUMENTS
(2021)
Article
Physics, Applied
Dominik Vasinka, Martin Bielak, Michal Neset, Miroslav Jezek
Summary: This study presents direct and inverse models for liquid crystal polarization transformation based on deep neural networks, radial basis functions, and linear interpolation. Using deep learning significantly improves accuracy, with decreasing errors as training data increases. The research has important implications for improving the control accuracy of liquid crystals in various fields.
PHYSICAL REVIEW APPLIED
(2022)
Article
Optics
Jan Grygar, Josef Hlousek, Jaromir Fiurasek, Miroslav Jezek
Summary: We experimentally certify the quantum non-Gaussian character of a photon number-resolving detector, demonstrating the adaptability of existing criteria for quantum non-Gaussianity to quantum measurements. We confirm the non-Gaussianity of a detector consisting of ten single-photon avalanche photodiodes and propose strategies such as injecting Gaussian background noise and using a third thermal state to expedite the certification process.
Article
Physics, Multidisciplinary
Stephan Grebien, Julian Goettsch, Boris Hage, Jaromir Fiurasek, Roman Schnabel
Summary: In this experiment, the multistep distillation of squeezed states was analyzed for the first time. By utilizing probabilistic subtraction and Gaussification, the squeeze factor was successfully increased, surpassing the limitations set by the pumped medium's effective nonlinearity.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Applied
Josef Hlousek, Ivo Straka, Miroslav Jezek
Summary: The linearity of single-photon detectors allows accurate optical measurements at low light levels and using non-classical light. However, the response of single-photon detectors can exhibit intriguing nonlinear effects that may influence the performed measurements.
APPLIED PHYSICS REVIEWS
(2023)
Article
Optics
Nikola Horova, Robert Starek, Michal Micuda, Jaromir Fiurasek, Michal Kolar, Radim Filip
Summary: In this study, we investigate states that maximize the mutual coherence in a two-qubit system and discover a nontrivial asymmetric optimal state. We experimentally generate this optimal state and also test the preparation of states with maximal mutual coherence. These results demonstrate the initial steps of controlling mutual quantum coherence in qubit systems.
Article
Optics
Jaromir Fiurasek
Summary: This article investigates interferometric schemes for linear optical noiseless quantum amplifiers. By using auxiliary Fock states and photon number measurements, optimal interferometric couplings are found to maximize the probability of success. The experiments show that the more general interferometric couplings can outperform the quantum scissors scheme. Additionally, the general form of single-mode linear optical quantum operations driven by auxiliary N-photon states is also discussed.
Article
Optics
Jaromir Fiurasek, Robert Starek, Michal Micuda
Summary: This study focuses on designing optimal interferometric schemes for the implementation of two-qubit linear-optical quantum filters diagonal in the computational basis. The filtering is achieved through the interference of two photons encoding the qubits and conditioning on the presence of a single photon in each output port. The optimal filters are those that maximize the overall success probability, which may require additional overhead in terms of reduced success probability.
Article
Optics
Radim Hosak, Ivo Straka, Ana Predojevic, Radim Filip, Miroslav Jezek
Summary: The study proposes a workflow for evaluating the quality of entanglement sources, estimating the potential performance of quantum entanglement sources in quantum key distribution protocols based on quantum state density matrices from theoretical models and experimental data. It highlights the trade-off between the generation rate and quality of entangled pairs due to the multiphoton nature of the generated quantum states. The research finds that the secure key rate of down-converted photon pairs is limited by intrinsic multiphoton contributions, and identifies an optimum gain for continuous-wave down-conversion sources.
Article
Optics
Ivo Straka, Miroslav Jezek
Summary: The proposed method allows for arbitrarily shaping and scaling the temporal intensity correlations of an optical signal locally, without periodic correlations. Experimental demonstration using stochastic intensity modulation was conducted, along with analysis and simulation of shaping both temporal correlations and photon statistics specified by the user. The study shows that temporal correlations, within the constraints of monotony and convexity, are independent of photon statistics and can take on any shape.
