Article
Optics
Shashank Gupta, Debarshi Das, A. S. Majumdar
Summary: This study demonstrates that a perfectly genuine tripartite steerable assemblage can be distilled from partially genuine tripartite EPR steerable assemblages, with high efficiency even using a small number of initial assemblages.
Article
Physics, Multidisciplinary
Mao-Sheng Li, Zhu-Jun Zheng
Summary: This paper discusses quantum nonlocality without entanglement and presents a set with genuine hidden nonlocality. The authors eliminate doubt by constructing a series of non-entangled sets with genuinely activated nonlocality.
NEW JOURNAL OF PHYSICS
(2022)
Article
Optics
Ivan Supic, Jean-Daniel Bancal, Yu Cai, Nicolas Brunner
Summary: The network structure allows for the existence of novel forms of quantum nonlocal correlations that cannot be explained by standard quantum Bell nonlocality. We introduce the concept of genuine network quantum nonlocality and demonstrate its operational approach that views standard quantum nonlocality as a resource for producing correlations in networks. By considering the bilocality network of entanglement swapping, we present examples of genuine network nonlocal correlations, including an example of quantum self-testing that relies on the network structure.
Article
Physics, Multidisciplinary
Liang Huang, Xue-Mei Gu, Yang-Fan Jiang, Dian Wu, Bing Bai, Ming-Cheng Chen, Qi-Chao Sun, Jun Zhang, Sixia Yu, Qiang Zhang, Chao-Yang Lu, Jian-Wei Pan
Summary: Nonlocality is a counterintuitive feature of nature that defies classical intuition. Recent investigations show that our physical world's nonlocality is at least tripartite, meaning that genuine tripartite nonlocal correlations cannot be replicated by any causal theory involving bipartite nonclassical resources and unlimited shared randomness. This study experimentally demonstrates genuine tripartite nonlocality in a network under strict locality constraints, using fair sampling assumption and postselection.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Multidisciplinary
Sebastien Designolle, Vatshal Srivastav, Roope Uola, Natalia Herrera Valencia, Will McCutcheon, Mehul Malik, Nicolas Brunner
Summary: This study theoretically formalizes and experimentally demonstrates a notion of genuine high-dimensional quantum steering, showing that higher-dimensional quantum entanglement can lead to stronger steering. Simple two-setting steering inequalities are derived to certify the presence of genuine high-dimensional steering, based on the connection between steering and incompatibility of quantum measurements. The experimental violation of these inequalities using macropixel photon-pair entanglement certifies genuine high-dimensional steering, with a reported minimum Schmidt number of n = 15 for an entangled state in dimension d = 31.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Multidisciplinary
Mahasweta Pandit, Artur Barasinski, Istvan Marton, Tamas Vertesi, Wieslaw Laskowski
Summary: This paper proposes an optimal and efficient numerical test for witnessing genuine multipartite nonlocality based on a geometric approach. It applies general tests to detect and characterize genuine n-way nonlocal correlations for various quantum systems. The paper also explores the extension of measurements beyond two and proposes a simple procedure to detect nonlocal correlations with high efficiency.
NEW JOURNAL OF PHYSICS
(2022)
Article
Quantum Science & Technology
Seungbeom Chin, Jung-Hoon Chun
Summary: This work presents a comprehensive approach to analyzing entanglement between subsystems generated by identical particles using SEA and microcausality, while amending the NLA method for quantifying entanglement of any type of identical particles, especially fermions with the parity superselection rule. The formal correspondence between identical and non-identical particle systems is useful for quantifying non-locality generated by identical particles, such as the violation of the maximal CHSH inequality and the GHJW theorem of identical particles.
QUANTUM INFORMATION PROCESSING
(2021)
Article
Physics, Multidisciplinary
Valentin Gebhart, Luca Pezze, Augusto Smerzi
Summary: This study investigates the generation and verification of genuine multipartite nonlocality (GMN) for quantum technological applications such as quantum privacy. It demonstrates that GMN can be shown through a postselection strategy that involves communication among multiple parties.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Multidisciplinary
Ying-Hui Yang, Guang-Wei Mi, Shi-Jiao Geng, Qian-Qian Liu, Hui-Juan Zuo
Summary: This paper investigates the relationship between strong nonlocality and genuine entanglement in four or more party systems. The concept of k-strong nonlocality is introduced and 2-strong nonlocality with genuine entanglement is demonstrated using sets of GHZ-like states. The open problem raised by Wang et al is solved and a set of GHZ-like states with n (+)-strong nonlocality in n-partite quantum systems is constructed.
Article
Optics
Dongkai Zhang, Xiaodong Qiu, Wuhong Zhang, Lixiang Chen
Summary: High-dimensional entangled states provide more channels for quantum information, and the continuous variable of angular position can be conveniently represented in discrete bases experimentally. By testing Hardy’s paradox, we reveal the high-dimensional entanglement in the angular-position degree of freedom, which leads to a sharper contradiction between quantum mechanics and classical theories.
Article
Optics
Rui Qu, Yunlong Wang, Xiaolin Zhang, Shihao Ru, Feiran Wang, Hong Gao, Fuli Li, Pei Zhang
Summary: The article presents a more robust method for certifying genuine high-dimensional quantum steering in noisy environments, surpassing previous restrictions and demonstrating its practicality through experimental demonstrations.
Article
Physics, Multidisciplinary
Bartosz Regula, Ryuji Takagi
Summary: The study develops a unified framework for characterizing one-shot transformations of dynamical quantum resources, establishing universal conditions for exact and approximate transformations in general resource theories. The framework encompasses all dynamical resources represented as quantum channels and can be applied to a wide range of physical settings. Through specific applications to quantum communication, the study provides exact expressions for one-shot quantum capacity and simulation cost, as well as to non-locality, contextuality, and measurement incompatibility.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Multidisciplinary
Da Zhang, David Barral, Yanpeng Zhang, Min Xiao, Kamel Bencheikh
Summary: In this study, a set of sufficient and necessary conditions for separability of the broad family of spontaneously generated three-mode non-Gaussian states is proposed. State-of-the-art conditions for genuine tripartite non-Gaussian entanglement are further derived. Applying these criteria to triple-photon states reveals that they are fully inseparable and genuinely entangled in moments of order 3n. These results establish a systematic framework for characterizing the entanglement of triple-photon states and thus foster their application in quantum information protocols.
PHYSICAL REVIEW LETTERS
(2023)
Article
Physics, Multidisciplinary
Ya-Li Mao, Zheng-Da Li, Sixia Yu, Jingyun Fan
Summary: This article investigates the nonlocality in a multipartite system. Theoretical and experimental studies reveal that the genuine multipartite nonlocal correlations cannot be explained by causal theories involving fewer-partite resources and global shared randomness.
PHYSICAL REVIEW LETTERS
(2022)
Article
Optics
Sebastien Designolle
Summary: Quantum systems of high dimensions have interesting properties in observing entanglement or other forms of correlations, making them attractive for experiments in quantum communication or quantum cryptography due to their improved resistance to noise. However, verifying the high-dimensional nature remains challenging, especially when weak assumptions are made on the parties involved, such as considering one of them as a black box. Recently, the concept of genuine high-dimensional steering has been introduced, allowing for a one-sided device-independent certification of the dimension of a bipartite shared state using only two measurements. In this study, the author overcomes the limitations by developing universal bounds on the incompatibility robustness for more than two measurements, which can serve as meaningful dimension certificates.
Article
Quantum Science & Technology
Simone Evaldo D'Aurelio, Mauro Valeri, Emanuele Polino, Valeria Cimini, Ilaria Gianani, Marco Barbieri, Giacomo Corrielli, Andrea Crespi, Roberto Osellame, Fabio Sciarrino, Nicolo Spagnolo
Summary: This article evaluates the application of Bayesian methods in multiple phase estimation, taking into account bounds that go beyond the usual assumption of large samples in parameter estimation. Experimental data generated from the output statistics of a three-arm interferometer is used, providing a blueprint for more comprehensive data analysis in quantum metrology.
QUANTUM SCIENCE AND TECHNOLOGY
(2022)
Article
Physics, Multidisciplinary
Zheng-Hao Liu, Hui-Xian Meng, Zhen-Peng Xu, Jie Zhou, Jing-Ling Chen, Jin-Shi Xu, Chuan-Feng Li, Guang-Can Guo, Adan Cabello
Summary: We address the lack of robustness in existing examples of contextuality in high-dimensional systems by identifying a family of noncontextuality inequalities whose maximum quantum violation grows with the dimension of the system. We show the practicality of this result by presenting an experimental test of contextuality in a seven-dimensional system, where we report a violation of 68.7 standard deviations. Our findings advance the investigation of high-dimensional contextuality and its role in quantum computation.
PHYSICAL REVIEW LETTERS
(2023)
Article
Chemistry, Physical
Giulio Tavani, Chiara Barri, Erfan Mafakheri, Giorgia Franzo, Michele Celebrano, Michele Castriotta, Matteo Di Giancamillo, Giorgio Ferrari, Francesco Picciariello, Giulio Foletto, Costantino Agnesi, Giuseppe Vallone, Paolo Villoresi, Vito Sorianello, Davide Rotta, Marco Finazzi, Monica Bollani, Enrico Prati
Summary: Recent advancements in QKD protocols have explored the use of erbium-doped LEDs as nonlaser sources for quantum key distribution. Silicon LEDs based on electroluminescence of Er:O complexes in Si have been fabricated on a 220 nm SOI wafer. The Er:O diodes showed emission rates of 5 x 10^6 photons/s at 1550 nm at room temperature, and their integration on the SOI platform allows for the development of silicon photon sources suitable for arbitrary-statistic-tolerant QKD protocols.
Article
Quantum Science & Technology
Federico Berra, Costantino Agnesi, Andrea Stanco, Marco Avesani, Sebastiano Cocchi, Paolo Villoresi, Giuseppe Vallone
Summary: We propose a modular design for a Quantum Key Distribution (QKD) source using iPOGNAC, a stable and calibration-free polarization modulation scheme, for both intensity and polarization encoding. This source is resistant to security vulnerabilities such as side channels and quantum hacking attacks. Our intensity modulation scheme allows flexible adjustment of intensity ratio and reduces patterning effects. The source has been implemented and tested in the near-infrared band, making it suitable for satellite-based QKD. The modularity of the source simplifies development, testing, and qualification, especially for space missions. Our work paves the way for the development of second-generation QKD satellites with excellent performance at higher security levels.
EPJ QUANTUM TECHNOLOGY
(2023)
Article
Quantum Science & Technology
Ilaria Gianani, Alessio Belenchia, Stefano Gherardini, Vincenzo Berardi, Marco Barbieri, Mauro Paternostro
Summary: Quantum coherence, a fundamental concept in quantum physics, has significant theoretical and technological implications. This study investigates how the coherence generated by a quantum gate is affected by unitary errors in the form of rotation-angle and rotation-axis errors. Numerical evidence supports that the statistics of local energy measurements on the output states of the gate effectively capture this information. Experimental data from a quantum optics setting further corroborate these findings.
QUANTUM SCIENCE AND TECHNOLOGY
(2023)
Article
Quantum Science & Technology
Massimiliano Guarneri, Ilaria Gianani, Marco Barbieri, Andrea Chiuri
Summary: Characterization of quantum objects through previous knowledge and the use of neural networks can lead to routine procedures for real-life components. In this study, a convolutional stage is introduced in a neural network to improve the tomographic estimate of parameters in quantum process tomography. The results demonstrate the viability of this approach as an effective tool operating on classical data produced by quantum systems.
ADVANCED QUANTUM TECHNOLOGIES
(2023)
Article
Physics, Multidisciplinary
Rocco Duquennoy, Maja Colautti, Pietro Lombardi, Vincenzo Berardi, Ilaria Gianani, Costanza Toninelli, Marco Barbieri
Summary: Two-photon interference is crucial for many quantum photonics devices and for testing the indistinguishability of photons. However, extracting relevant parameters, such as the central frequency difference, can be difficult when the time-spectral profile becomes more complex. In this study, a semiparametric method using singular spectral analysis is proposed to reduce these effects and accurately evaluate frequency separation. This approach enables robust and efficient online monitoring of quantum emitters without the need for fitting.
PHYSICAL REVIEW RESEARCH
(2023)
Article
Physics, Multidisciplinary
Junior R. Gonzales-Ureta, Ana Predojevic, Adan Cabello
Summary: We have discovered a new type of Bell inequalities that are optimal for state-independent contextuality (SI-C) sets, allowing for robust nonlocality in the face of noise. This opens up possibilities for studying the applications of nonlocality and contextuality in experiments.
PHYSICAL REVIEW RESEARCH
(2023)
Correction
Optics
Ilaria Gianani, Vincenzo Berardi, Marco Barbieri
Article
Optics
Jan Sperling, Ilaria Gianani, Marco Barbieri, Elizabeth Agudelo
Summary: This paper explores measurements in the quantum domain, including the nature of the measurement process and their applications in quantum information processing protocols. The authors propose a method that allows for the determination of nonlocal quantum coherence in positive-operator-valued measures through negative contributions in a joint distribution. This approach is applied to experimental data for detectors that project onto Bell states, providing a versatile toolbox for analyzing measurements in quantum science and technology.
Article
Quantum Science & Technology
Ilaria Gianani, Claudia Benedetti
Summary: The study performs multiparameter estimation of the Hamiltonian parameters characterizing a continuous-time quantum walk using a deep neural network model fed with experimental probabilities. The results show that the neural network acts as a nearly optimal estimator when estimating two or three parameters.
AVS QUANTUM SCIENCE
(2023)
Article
Quantum Science & Technology
Kishor Bharti, Maharshi Ray, Zhen-Peng Xu, Masahito Hayashi, Leong-Chuan Kwek, Adan Cabello
Summary: This study addresses the problem of self-testing quantum correlations using tools from graph theory. It is found that the set of quantum correlations, BQ, is strictly contained in a set associated with a graph, 0(G), which is easier to characterize. When the optimum values of BQ and 0(G) coincide, self-testing can be demonstrated by proving self-testability with 0(G). This approach also connects self-testing to open problems in discrete mathematics.
Article
Optics
Ali Asadian, Adan Cabello
Summary: This article introduces a scheme to address the problem of producing contextual correlations in sequences of measurements on single quantum systems. By encoding quantum information in indistinguishable bosons in multiple modes and performing ideal measurements with auxiliary qubits, the authors were able to realize sequential quantum measurements on high-dimensional quantum systems and generate contextuality that cannot be simulated by classical light.
Article
Optics
Ilaria Gianani, Vincenzo Berardi, Marco Barbieri
Summary: Capturing specific types of quantum correlation in quantum networking is crucial, with different routes highlighting various aspects of these correlations. Recent experimental results demonstrate how steering affects the metrological abilities of a bipartite state, confirming its relevance and comparing it to existing alternatives.
Article
Optics
A. Chiuri, I Gianani, V Cimini, L. De Dominicis, M. G. Genoni, M. Barbieri
Summary: Frequency correlations are a powerful tool for spectral analysis of difficult-to-measure objects. This study compares the metrological capabilities of quantum and classical ghost spectrometers and demonstrates the potential advantages of quantum ghost spectrometry.
