Article
Physics, Multidisciplinary
Francisco Revson Fernandes Pereira, Stefano Mancini
Summary: This paper presents a general framework called quantum reading for statistical discrimination of an ensemble of quantum channels. A simple yet effective protocol is proposed to reduce the error probability in distinguishing the ensemble of channels using classical error-correcting codes. The results show that BCH codes in conjunction with Dolinar receivers are the optimal strategy for error mitigation in quantum reading.
Article
Physics, Multidisciplinary
Ang Liu, Xiu-Bo Chen, Shengwei Xu, Zhuo Wang, Zhengyang Li, Liwei Xu, Yanshuo Zhang, Ying Chen
Summary: Blockchain technology provides data integrity protection and trust mechanisms in transactions for distributed networks, but it faces threats from the breakthrough in quantum computation technology. This paper presents a practical and efficient quantum-secure blockchain scheme, incorporating a consensus mechanism and an identity-based quantum signature, to address the challenges in the quantum era.
Article
Physics, Multidisciplinary
Martin J. Renner, Armin Tavakoli, Marco Tulio Quintino
Summary: This article discusses the transmission of qubit states from Alice to Bob and general measurements in the form of positive operator-valued measures (POVMs). The research found that the statistics obtained in any quantum protocol can be simulated using shared randomness and only two bits of classical communication. Furthermore, it was proven that two bits of communication is the minimum cost for a perfect classical simulation. The methods were also applied to Bell scenarios, extending the well-known Toner and Bacon protocol, and demonstrating that two bits of communication are sufficient to simulate all quantum correlations associated with arbitrary local POVMs applied to any entangled two-qubit state.
PHYSICAL REVIEW LETTERS
(2023)
Article
Physics, Multidisciplinary
X. Ma, J. J. Viennot, S. Kotler, J. D. Teufel, K. W. Lehnert
Summary: In this study, non-classical states are created by quadratically coupling motion to the energy levels of a Cooper-pair box qubit. The mechanical oscillator is dissipatively stabilized in a state with a large mean phonon number and sub-Poissonian number fluctuations, showing a striking feature of the quadratic coupling: the recoil of the mechanical oscillator caused by qubit transitions.
Article
Quantum Science & Technology
Alok Shukla, Prakash Vedula
Summary: A hybrid classical-quantum approach for evaluating multi-dimensional Walsh-Hadamard transforms is proposed, along with its applications in quantum image processing. The proposed approach has lower computational complexity and efficiently utilizes qubits for image processing.
QUANTUM INFORMATION PROCESSING
(2022)
Article
Physics, Multidisciplinary
Alessandro Sergi, Antonino Messina, Carmelo M. Vicario, Gabriella Martino
Summary: The study introduces a quantum-classical Hamiltonian model for studying the interface between the quantum and the classical world in the brain. The model incorporates quantum variables represented by spinors and classical or semi-classical treatment of electromagnetic fields and phonon modes. Temperature control through dedicated thermostats allows incorporation of quantum zero-point effects. Numerical simulations are planned for future work.
Article
Cultural Studies
Helle Strandgaard Jensen, Josephine Moller Jensen, Alexander Ulrich Thygesen, Max Odsbjerg Pedersen
Summary: This article contributes methodologically to the field of digital memory studies by demonstrating a possible approach for memory studies scholars to use digital methods while remaining connected to traditional research. It showcases an analytical workflow for reading large quantities of tweets using the Twitter API and argues that this combination can greatly enhance data collection and analysis practices in memory studies. The article also shows how the Twitter API enables systematic and large-scale tweet collection, reducing dependence on the algorithmic bias of the platform's regular interface.
Article
Quantum Science & Technology
Avinash Chalumuri, Raghavendra Kune, B. S. Manoj
Summary: This study introduces the Quantum Multi-Class Classifier (QMCC), a hybrid model based on both quantum and classical computers for machine learning tasks, utilizing quantum properties such as superposition and entanglement to achieve high classification accuracy. Quantum simulations on benchmark datasets demonstrate that the proposed QMCC model achieved classification accuracy of 92.10% for the Iris dataset, 89.50% for the Banknote Authentication dataset, and 91.73% for the Wireless Indoor Localization dataset.
QUANTUM INFORMATION PROCESSING
(2021)
Article
Physics, Multidisciplinary
Perez-Delgado A. Carlos, Sai Vinjanampathy
Summary: Research has shown that algorithms based on higher-order Hamiltonians can achieve a quadratic speed-up over classical computation, and are grounded in the same physics as quantum advantage for metrology and battery charging. Therefore, advancements in implementing quantum advantage in these scenarios could potentially be utilized to speed up computation.
NEW JOURNAL OF PHYSICS
(2021)
Article
Chemistry, Analytical
Giuseppe Ortolano, Ivano Ruo-Berchera
Summary: This article analyzes the optimized quantum sensing protocol for enhancing the readout accuracy of optical memories in the presence of imprecise writing. The study shows that quantum entanglement technology can effectively improve the reading performance of ideal optical memories and the proposed strategy is feasible with current technology and relatively robust to detection and optical losses. Furthermore, the research has implications for pattern identification in biological systems, spectrophotometry, and optical measurements for extracting information.
Article
Quantum Science & Technology
H. Hajihoseinlou, B. Ahansaz, F. Eghbalifam, M. Behboudnia
Summary: This study investigates the dynamical behavior of quantum correlations between two identical atoms driven by classical fields and placed in two independent non-Markovian environments. It reveals that the global quantum discord and local quantum uncertainty, as measures of quantum correlations, can be controlled and preserved by manipulating the strength of the classical driving. Further, it demonstrates that the decay process of quantum correlations can be slowed down by adjusting the central frequency of the reservoir.
QUANTUM INFORMATION PROCESSING
(2023)
Article
Optics
S. Zhang, S. Seidelin, R. Le Targat, P. Goldner, B. Fang, Y. Le Coq
Summary: The possibility of generating a narrow spectral hole in a rare-earth doped crystal opens up various applications, including the realization of an ultrastable laser. Temperature-induced pressure changes in a buffer gas surrounding the crystal can help counterbalance the direct effect of temperature fluctuations on the spectral hole resonant frequency. By measuring frequency shifts as a function of temperature for different buffer gas pressures, a "magic environment" can be identified where the spectral hole is largely insensitive to temperature.
Article
Computer Science, Artificial Intelligence
Yanying Liang, Wei Peng, Zhu-Jun Zheng, Olli Silven, Guoying Zhao
Summary: Inspired by classical neural networks, a novel hybrid quantum-classical neural network with deep residual learning (Res-HQCNN) is proposed in this paper, which shows better performance in learning unknown unitary transformations and handling noisy data through experiments.
Review
Optics
Shi-Hai Wei, Bo Jing, Xue-Ying Zhang, Jin-Yu Liao, Chen-Zhi Yuan, Bo-Yu Fan, Chen Lyu, Dian-Li Zhou, You Wang, Guang-Wei Deng, Hai-Zhi Song, Daniel Oblak, Guang-Can Guo, Qiang Zhou
Summary: Quantum networks are crucial for quantum information science, enabling applications in quantum communication, computation, metrology, and fundamental tests. The main challenge lies in distributing entangled flying qubits to separate nodes, where quantum interfaces or transducers map the entanglement onto fixed qubits. Extensive efforts over the past two decades have led to significant progress in entangling quantum nodes and building a global quantum network using various physical systems. This review discusses the development of quantum networks and experimental advancements, comparing the potential and merits of systems such as single atoms, cold atomic ensembles, trapped ions, diamonds with nitrogen-vacancy centers, and solid-state hosts doped with rare-earth ions.
LASER & PHOTONICS REVIEWS
(2022)
Article
Multidisciplinary Sciences
Byoung S. Ham
Summary: The USCKD protocol is a completely different approach to achieving unconditional security in the purely classical regime, utilizing classical channels and orthogonal bases to provide unconditional security through path superposition-based reversible unitary transformations.
SCIENTIFIC REPORTS
(2021)
Article
Physics, Multidisciplinary
Masoud Ghalaii, Stefano Pirandola
Summary: Since the invention of the laser in the 60s, the free-space optical channel has been a fundamental communication channel. However, studying this channel is more difficult than a stable fiber-based link due to effects such as diffraction, refraction, atmospheric extinction, pointing errors, and turbulence. Recent research has shown that it is possible to achieve ultimate performances in quantum communications and extract composable keys in the challenging regime of moderate-to-strong turbulence in free-space channels.
COMMUNICATIONS PHYSICS
(2022)
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
Physics, Applied
Cillian Harney, Alasdair I. Fletcher, Stefano Pirandola
Summary: This research combines the theory of point-to-point free-space channel capacities and end-to-end quantum network capacities to develop important tools for studying hybrid free-space quantum networks. By using modular quantum network architectures and physically connected models, the performance of the networks can be idealized and channel conditions for optimal performance can be derived. This research reveals crucial infrastructure demands for future satellite-based global quantum internet and hybrid wired and wireless metropolitan quantum networks.
PHYSICAL REVIEW APPLIED
(2022)
Article
Quantum Science & Technology
Cillian Harney, Stefano Pirandola
Summary: This study examines the achievable end-to-end rates for noisy-repeater quantum networks by introducing internal losses and noise into repeater devices. It presents a general formalism to calculate tight performance bounds for high-rate quantum communications.
QUANTUM SCIENCE AND TECHNOLOGY
(2022)
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
Multidisciplinary Sciences
Alasdair Fletcher, Stefano Pirandola
Summary: A continuous variable, measurement device independent quantum key distribution protocol is analyzed, allowing three parties to connect for quantum conferencing. By utilizing a generalized Bell detection and a postselection procedure, the protocol achieves improved rate-distance performance under a collective pure-loss attack.
SCIENTIFIC REPORTS
(2022)
Article
Quantum Science & Technology
Masoud Ghalaii, Panagiotis Papanastasiou, Stefano Pirandola
Summary: In this paper, the authors address the issue of composable security in finite-sized Gaussian quantum networks, with generally untrusted nodes. They propose a general methodology for parameter estimation based on shared data and demonstrate its effectiveness using a chain of identical quantum links as an example. Additionally, they discuss the potential of quantum amplifier-assisted chains to surpass the fundamental limits and highlight the need for further research in network/chain designs.
NPJ QUANTUM INFORMATION
(2022)
Article
Optics
Alexander G. Mountogiannakis, Panagiotis Papanastasiou, Stefano Pirandola
Summary: This article focuses on the performance of a practical continuous-variable quantum key distribution protocol, particularly on the postprocessing steps involving finite-size effects in the reconciliation process. The quantum communication process is simulated and output data is postprocessed using parameter estimation, error correction, and privacy amplification, aiming to optimize the protocol's practical implementations.
Proceedings Paper
Quantum Science & Technology
Panagiotis Papanastasiou, Stefano Pirandola
Summary: We extend the security of continuous variable quantum key distribution by applying one-way and two-way quantum communication to a multi-way setting. We assume the signals are encoded using Gaussian-modulated coherent states and travel through Gaussian channels characterized by loss and thermal noise. We quantify the reverse-reconciliation performance of the protocol for even and odd numbers of signal exchange.
PHOTONICS FOR QUANTUM 2022
(2022)
Proceedings Paper
Quantum Science & Technology
Stefano Pirandola
Summary: This article provides a general overview of the different types of nodes and associated security levels that can be considered in a quantum key distribution network. It discusses various scenarios for QKD repeater chains and network architectures.
PHOTONICS FOR QUANTUM 2022
(2022)
Article
Physics, Multidisciplinary
Riccardo Laurenza, Nathan Walk, Jens Eisert, Stefano Pirandola
Summary: The derivation of ultimate limits to communication over certain quantum repeater networks has provided valuable benchmarks for assessing near-term quantum communication protocols, but the performance of practical implementations remains unanswered. This study quantifies the impact of loss in repeater stations on the maximum attainable rates for quantum communication over linear repeater chains and more complex networks. The results show that the maximum rate cannot exceed a quantity dependent on the loss of a single station, even with an increased number of repeater stations.
PHYSICAL REVIEW RESEARCH
(2022)
Article
Quantum Science & Technology
Naomi R. Solomons, Alasdair Fletcher, Djeylan Aktas, Natarajan Venkatachalam, Soren Wengerowsky, Martin Loncaric, Sebastian P. Neumann, Bo Liu, Zeljko Samec, Mario Stipcevic, Rupert Ursin, Stefano Pirandola, John G. Rarity, Siddarth Koduru Joshi
Summary: The global interest in quantum networks is driven by the security provided by the laws of physics. Deploying quantum networks faces challenges in scaling the physical hardware and optimizing the network layers. This article discusses the usefulness of authentication-transfer and flooding protocols through experimental demonstrations on an eight-user quantum network test bed.
Article
Quantum Science & Technology
Cillian Harney, Stefano Pirandola
Summary: In this work, a large-scale quantum network model called weakly regular architectures is introduced to study the design of global quantum networks. Through a comparison of theoretical performance and realistic satellite quantum communication protocols, the efficacy of satellite-based technologies for global quantum communications is rigorously proven.
Article
Physics, Multidisciplinary
Alexander G. Mountogiannakis, Panagiotis Papanastasiou, Boris Braverman, Stefano Pirandola
Summary: Continuous-variable quantum key distribution establishes a secret key between two remote parties using Gaussian-modulated coherent states. The secret key rate depends on the loss and noise in the communication channel, as well as the data processing steps of parameter estimation, error correction, and privacy amplification. High signal-to-noise regime requires high-rate low-density parity check codes.
PHYSICAL REVIEW RESEARCH
(2022)
Article
Optics
Athena Karsa, Jacques Carolan, Stefano Pirandola
Summary: Channel-position finding is the task of determining the location of a target channel, and using quantum states and entanglement can provide quantum advantages. By considering different quantum sources, quantum enhancement can be achieved.
