Article
Physics, Multidisciplinary
P. Vidil, K. Edamatsu
Summary: Measuring a nonlocal observable on a space-like separated quantum system is described as a challenging task. This study presents a new method to achieve this without necessarily requiring a maximally-entangled ancilla, opening up possibilities for more economical nonlocal measurements with applications in various fields. The explicit relationship between measurement strength and the amount of ancillary entanglement needed provides a new perspective on the connections between quantum nonlocality, entanglement, and information transmission.
NEW JOURNAL OF PHYSICS
(2021)
Article
Multidisciplinary Sciences
Hsuan-Hao Lu, Karthik Myilswamy, Ryan S. Bennink, Suparna Seshadri, Mohammed S. Alshaykh, Junqiu Liu, Tobias J. Kippenberg, Daniel E. Leaird, Andrew M. Weiner, Joseph M. Lukens
Summary: With the development of integrated biphoton frequency combs, quantum information processing in the frequency domain has attracted more attention in recent years. To address the scalability issue of frequency mixing operations, the authors propose a novel solution that utilizes pulse shapers and electro-optic phase modulators to perform random operations. They successfully verify the entanglement and reconstruct the full density matrix of biphoton frequency combs, achieving the highest dimension for frequency bins to date. The employed Bayesian statistical model can be tailored to various quantum systems with restricted measurement capabilities, providing an opportunistic tomographic framework.
NATURE COMMUNICATIONS
(2022)
Article
Physics, Multidisciplinary
Lorcan O. Conlon, Falk Eilenberger, Ping Koy Lam, Syed M. Assad
Summary: The study introduces a protocol for using collective measurements to distinguish quantum states, which achieves a lower probability of error compared to non-entangling measurements. Experimental results demonstrate the effectiveness of this approach.
COMMUNICATIONS PHYSICS
(2023)
Article
Physics, Multidisciplinary
Michael G. Jabbour, Jonatan Bohr Brask
Summary: We present a simple sufficient criterion to determine the locality of correlations obtained from measurements on a Gaussian quantum state. The criterion involves the construction of a local-hidden-variable model that utilizes a portion of the inherent Gaussian noise of the state for the measurements. We demonstrate the application of our criterion in the context of displaced photodetection on a two-mode squeezed state, where it reveals the presence of a local-hidden-variable model for a specific range of parameters despite the entanglement of the state.
PHYSICAL REVIEW LETTERS
(2023)
Article
Optics
David S. Simon, Christopher R. Schwarze, Alexander Sergienko
Summary: This paper investigates the properties of Grover multiports interferometers and discovers that they have capabilities beyond traditional beam-splitter-based interferometers, such as easily controlled interpolation between Hong-Ou-Mandel and anti-HOM behavior, as well as simultaneous measurement of three independent phases.
Article
Quantum Science & Technology
D. M. Tennant, X. Dai, A. J. Martinez, R. Trappen, D. Melanson, M. A. Yurtalan, Y. Tang, S. Bedkihal, R. Yang, S. Novikov, J. A. Grover, S. M. Disseler, J. Basham, R. Das, D. K. Kim, A. J. Melville, B. M. Niedzielski, S. J. Weber, J. L. Yoder, A. J. Kerman, E. Mozgunov, D. A. Lidar, A. Lupascu
Summary: In this study, the properties of a spin chain implemented with superconducting flux circuits are explored, serving as a connectivity medium between two superconducting qubits. The experiment demonstrates that the chain has long-range, cross-chain correlations and enables interactions between the two end qubits mediated by the coupler chain. This work is of direct relevance to near term quantum annealing processors for generating long-range, coherent coupling between qubits.
NPJ QUANTUM INFORMATION
(2022)
Article
Optics
Rikizo Ikuta, Toshiki Kobayashi, Tomohiro Yamazaki, Nobuyuki Imoto, Takashi Yamamoto
Summary: The research demonstrates a wide-bandwidth and efficient photonic Rabi oscillation based on cavity-enhanced nonlinear optical interaction, achieving full-cycle oscillation. The system shows versatile manipulation beyond the frequency degree of freedom, making it valuable for applications in photonic quantum information processing.
Article
Materials Science, Multidisciplinary
Dai-Gyoung Kim, Arfan Anjum, Muhammad Asif Farooq, Asif Mushtaq, Zahid Hussain Shamsi
Summary: In this paper, an innovative approach is proposed for quantum teleportation of multi-qubit physical state into an error correctable multi-qubit logical state. An efficient quantum error correction scheme is applied to detect and correct errors in the teleported logical state. The proposed mechanism is substantiated by teleporting an eight-qubit physical state via a four-qubit cluster state.
RESULTS IN PHYSICS
(2023)
Article
Physics, Multidisciplinary
Victor Montenegro, Gareth Sion Jones, Sougato Bose, Abolfazl Bayat
Summary: This study introduces a new method to achieve quantum-enhanced sensitivity in a many-body probe by utilizing the nature of quantum measurement without prior entanglement. By performing a sequence of local measurements, the sensing precision can be improved, reaching the Heisenberg limit.
PHYSICAL REVIEW LETTERS
(2022)
Article
Quantum Science & Technology
Mahdi Salehi, Seyed Javad Akhtarshenas, Mohsen Sarbishaei, Hakimeh Jaghouri
Summary: Mutually unbiased measurements generalize mutually unbiased bases, with a wide range of purities and the ability to construct orthogonal matrices through their spectra. Only two MUMs are needed to detect entanglement in bipartite states, with one assigning zero mean value and the other assigning negative mean value, proportional to an entanglement monotone.
QUANTUM INFORMATION PROCESSING
(2021)
Article
Quantum Science & Technology
Mateo Casariego, Yasser Omar, Mikel Sanz
Summary: In this paper, a quantum-enhanced, idler-free sensing protocol is proposed to measure the response of a target object to the frequency of a probe in a noisy and lossy scenario. The use of a bi-frequency quantum state as the resource allows for more accurate estimation of the parameter lambda, and the quantum enhancement is shown to be noise-resilient and dependent on the reflectivity of the probed object. The study also proposes an experimental scheme based on elementary quantum optical transformations and highlights potential applications in radar and medical imaging.
ADVANCED QUANTUM TECHNOLOGIES
(2022)
Review
Engineering, Electrical & Electronic
Mario Mastriani
Summary: In this study, an improved and generalized superdense coding protocol is developed, leading to a novel quantum key secure communication protocol utilizing an N-bit key, optical multiplexers and demultiplexers, and quantum repeaters based on entanglement swapping. The new protocol allows simultaneous transmission of N-bit encrypted information through optical channels. Implementations on the Quirk simulator and the IBM Q Experience program are conducted, along with an analysis of errors introduced by the number of quantum repeaters. Additionally, the advantages of using an optical link for quantum communication between submerged submarines in the presence of a third-party eavesdropper are discussed.
OPTICAL AND QUANTUM ELECTRONICS
(2023)
Article
Optics
Tian-Xiang Lu, Xing Xiao, Liu-Sha Chen, Qian Zhang, Hui Jing
Summary: In this study, the authors investigate the magnomechanically induced transparency effect in a cavity magnomechanical system, focusing on the role of magnon squeezing in enhancing and controlling the group delay of the transmitted light. They found that magnon squeezing strongly affects the magnon number and enables steerable transmission rate and controllable fast-to-slow light switching. Their results provide useful tools for engineering cavity magnomechanical devices with magnon squeezing for applications such as light propagation, storage, and precision measurements of weak signals.
Article
Quantum Science & Technology
Debadrita Ghosh, Thomas Jennewein, Urbasi Sinha
Summary: This paper fills the gap in determining entanglement monotones (EMs) in entangled qudit states. Analytical relations between statistical correlation measures and standard EMs are derived, and experimentally measured for two-qutrit pure states. The results provide valuable insights into the operational implications and non-monotonicity of EMs in bipartite pure qudit states.
QUANTUM SCIENCE AND TECHNOLOGY
(2022)
Article
Physics, Multidisciplinary
Amjad Sohail, Rizwan Ahmed, Rida Zainab, Chang-shui Yu
Summary: This study is based on a theoretical proposal for quantum steering, non-locality, and entanglement in a two microwave cavities based magnomechanical system. The system's dynamics show a complementary relationship among different bipartitions, with the entanglement of microwave cavity fields enhancing and being more robust against thermal effects. This highlights the importance and potential applications of the magnomechanical system in quantum tasks.
Article
Multidisciplinary Sciences
Kai Sun, Zheng-Hao Liu, Yan Wang, Ze-Yan Hao, Xiao-Ye Xu, Jin-Shi Xu, Chuan-Feng Li, Guang-Can Guo, Alessia Castellini, Ludovico Lami, Andreas Winter, Gerardo Adesso, Giuseppe Compagno, Rosario Lo Franco
Summary: This study experimentally demonstrates the different contributions to quantum coherence from identical and nonidentical particles, and proves that independent indistinguishable particles can serve as controllable resources of coherence and entanglement.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2022)
Article
Physics, Multidisciplinary
Benjamin Yadin, Hyejung H. Jee, Carlo Sparaciari, Gerardo Adesso, Alessio Serafini
Summary: In this study, the problem of state transformations in the presence of catalysts is examined within the framework of Gaussian thermal resource theory. The results show that strong catalysts are ineffective for the single mode case, while weak catalysts can achieve more final system states. Necessary conditions for Gaussian thermal state transformations are derived for different numbers of modes, including strong catalysts, approximate transformations, and weak catalysts with and without a thermal bath.
JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL
(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
Physics, Multidisciplinary
Ludovico Lami, Ladislav Mista Jr, Gerardo Adesso
Summary: The article establishes upper bounds on the amount of secret key that can be extracted from quantum Gaussian states using local Gaussian operations, local classical processing, and public communication. The authors prove that the key is bounded by the Renyi-2 Gaussian entanglement of formation EGF,2 for certain communication scenarios. They also propose that this bound coincides with the secret key rate of Gaussian states under specific conditions. Additionally, the authors demonstrate a gap between the secret key rates obtainable with arbitrary versus Gaussian operations.
PHYSICAL REVIEW RESEARCH
(2023)
Article
Physics, Multidisciplinary
Lorena C. Bianchet, Natalia Alves, Laura Zarraoa, Tomas Lamich, Vindhiya Prakash, Morgan W. Mitchell
Summary: In this study, we present precise subwavelength optical intensity measurements using a single trapped 87Rb atom as a sensor. The intensity is measured by the scalar ac Stark shift it produces on the hyperfine transition of the D2 line. We demonstrate the method by measuring the intensity at the focus of an optical tweezer.
PHYSICAL REVIEW RESEARCH
(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.
Article
Optics
Sven Bodenstedt, Morgan W. Mitchell, Michael C. D. Tayler
Summary: This study discusses procedures for error-tolerant spin control in environments that allow transient, large-angle reorientation of a magnetic bias field. By using short sequences of nonresonant magnetic-field pulses in a laboratory-frame meridional plane, robust z inversion in proton (H-1) nuclear magnetic resonance near Earth's field is demonstrated.
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
Optics
Emre Koese, Gerardo Adesso, Daniel Braun
Summary: In this study, we theoretically investigate the ultimate resolution achievable with passive remote sensing in the microwave regime used for satellite observations of Earth, such as the SMOS mission. We provide a fully quantum mechanical analysis of the problem, considering thermal distributions of microscopic currents on the surface to be imaged and their coherent mixture with the electromagnetic field, which is then measured using an array of antennas. We derive the optimal detection modes and measurement schemes that can saturate the quantum Cram??r-Rao bound for the chosen parameters, and find that a quantum enhancement of spatial resolution by more than a factor of 20 should be possible in certain parameter regimes.
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.