Article
Physics, Multidisciplinary
Mladen Pavicic
Summary: This study presents a general method for generating non-Kochen-Specker hypergraphs and provides examples in high-dimensional spaces. The automated generation approach is able to meet the size and structure requirements.
Article
Physics, Multidisciplinary
Karol Horodecki, Jingfang Zhou, Maciej Stankiewicz, Roberto Salazar, Pawel Horodecki, Robert Raussendorf, Ryszard Horodecki, Ravishankar Ramanathan, Emily Tyhurst
Summary: Quantum contextuality, a recognized resource in quantum communication and computing, is quantified by the rank of contextuality (RC), representing the minimum number of non-contextual behaviors required to simulate a contextual behavior. The logarithm of RC serves as a natural contextuality measure, satisfying properties like faithfulness, monotonicity, and additivity under tensor product. Examples demonstrate the connection between this quantifier and the arboricity of an underlying hypergraph, highlighting its relevance in various research areas.
NEW JOURNAL OF PHYSICS
(2023)
Article
Multidisciplinary Sciences
D. P. Nadlinger, P. Drmota, B. C. Nichol, G. Araneda, D. Main, R. Srinivas, D. M. Lucas, C. J. Ballance, K. Ivanov, E. Y-Z Tan, P. Sekatski, R. L. Urbanke, R. Renner, N. Sangouard, J-D Bancal
Summary: This study presents the experimental realization of a complete quantum key distribution protocol immune to attacks, providing device-independent security. By generating entanglement between two trapped-ion qubits using an improved optical fibre link, a large number of key bits were obtained with device-independent security. Measures were taken to ensure the security of measurement results.
Article
Physics, Multidisciplinary
Martti Karvonen
Summary: The resource theory of contextuality does not allow for catalysts, which also applies to nonlocality; furthermore, even though entanglement can be transformed using catalysts, it behaves differently from nonlocality as a resource.
PHYSICAL REVIEW LETTERS
(2021)
Review
Physics, Multidisciplinary
Costantino Budroni, Adan Cabello, Otfried Guehne, Matthias Kleinmann, Jan-Ake Larsson
Summary: This article introduces the Kochen-Specker theorem, a central result in the foundations of quantum mechanics, and its conflict with classical models. It reviews several proofs of the theorem and different notions of contextuality, and discusses the connections between contextuality and nonlocality or graph theory. Finally, it reviews the applications of contextuality in quantum information processing.
REVIEWS OF MODERN PHYSICS
(2022)
Article
Computer Science, Artificial Intelligence
Ping Wang, Weiqian Chen, Songlian Lin, Liyan Liu, Zhiwei Sun, Fangguo Zhang
Summary: This paper proposes a consensus algorithm based on quantum random numbers, which improves the randomness and fairness of the consensus process by introducing verifiable quantum random numbers, and requires minimal computation for users.
INTERNATIONAL JOURNAL OF INTELLIGENT SYSTEMS
(2022)
Article
Quantum Science & Technology
Akash Kundu, Jaroslaw Adam Miszczak
Summary: This research describes a simple procedure based on the variational quantum eigensolver for comparing the similarity between quantum devices. The procedure combines Choi-Jamiolkowski isomorphism with the variational hybrid quantum-classical procedure for matrix diagonalization. By analyzing its action on random quantum channels and discussing its sensitivity to noise, numerical results demonstrate its feasibility in realistic scenarios.
QUANTUM SCIENCE AND TECHNOLOGY
(2022)
Article
Physics, Multidisciplinary
Konrad Schlichtholz, Antonio Mandarino, Marek Zukowski
Summary: This article discusses the paradoxical features of quantum theory in fixed number of particles in quantum fields. The authors introduce a representation of the su(2) algebra using boson number states in two modes to assess nonclassicality of bosonic fields states. They show contextuality, violation of local realism, and formulate entanglement indicators using this representation. They further derive a non-contextuality inequality, revealing a bosonic Peres-Mermin square. The effectiveness of non-classicality indicators is demonstrated using the 2 x 2 bright squeezed vacuum state and the bright-GHZ state resulting from multiple three photon emissions in a parametric process.
NEW JOURNAL OF PHYSICS
(2022)
Article
Computer Science, Information Systems
Harshil Bhatia, Edith Tretschk, Christian Theobalt, Vladislav Golyanik
Summary: This study explores how qubits in modern quantum annealers can generate truly random numbers. The researchers demonstrate how the annealing process can be used to measure thousands of random binary numbers simultaneously. These numbers can then be converted into uniformly distributed natural or real numbers within desired ranges. The study also discusses the properties of the observed qubits and various physical factors that impact the performance of the generator.
Article
Quantum Science & Technology
Francisco Orts, Ernestas Filatovas, Ester M. Garzon, Gloria Ortega
Summary: This paper proposes a customizable circuit design to generate random numbers that can be used by current quantum devices. It also presents a state-of-the-art comparator circuit, which is highly efficient in terms of qubits, T-count, and T-depth. Both circuits provide valuable tools for quantum applications and algorithms that require random number generation or comparison operations.
EPJ QUANTUM TECHNOLOGY
(2023)
Article
Quantum Science & Technology
Kaiyan Yang, Xiao Zeng, Yujing Luo, Guowu Yang, Lan Shu, Miguel Navascues, Zizhu Wang
Summary: There has been growing interest in treating many-body systems as Bell scenarios, investigating contextuality in three different scenarios in 1D models, and providing evidence on the dimension required for contextuality to emerge.
NPJ QUANTUM INFORMATION
(2022)
Article
Physics, Multidisciplinary
Dian Wu, Qi Zhao, Xue-Mei Gu, Han-Sen Zhong, You Zhou, Li-Chao Peng, Jian Qin, Yi-Han Luo, Kai Chen, Li Li, Nai-Le Liu, Chao-Yang Lu, Jian-Wei Pan
Summary: This study demonstrates robust self-testing for multiphoton genuinely entangled quantum states, certifying four-photon entanglement in Greenberger-Horne-Zeilinger states and linear cluster states with fidelities of 0.957 and 0.945, respectively. By observing input-output statistics, the qualities of these entangled states with respect to realistic noise were estimated in a device-independent manner.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Multidisciplinary
Philippe Grangier
Summary: The violation of Bell's inequality and classical local realism is attributed to quantum mechanics violating predictive completeness, allowing contextual inferences to be made. Completing the usual quantum state requires specifying the measurement context rather than searching for hidden variables.
Article
Physics, Multidisciplinary
Nicola Biagi, Martin Bohmann, Elizabeth Agudelo, Marco Bellini, Alessandro Zavatta
Summary: This article introduces a phase-space inequalities method for certifying nonclassicality of quantum states, and demonstrates its practicality and sensitivity through experiments. The results show that the inequality conditions can detect nonclassicality even in cases of high losses and where other methods fail to reveal it.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Multidisciplinary
Hollis Williams
Summary: This article discusses the issue of eigenvalues in quantum mechanics and proposes a possible solution through causal relations, which eliminates the need for and appeal of hidden variable models.
Review
Physics, Multidisciplinary
Weikang Li, Dong-Ling Deng
Summary: Machine learning has achieved significant success in various applications, and its integration with quantum physics opens up new frontiers for quantum machine learning. This review provides a comprehensive overview of quantum classifiers, with a focus on recent advancements. Different quantum classification algorithms are reviewed, along with the introduction of variational quantum classifiers and the challenges they face. The vulnerability of quantum classifiers in adversarial learning and recent experimental progress are also discussed.
SCIENCE CHINA-PHYSICS MECHANICS & ASTRONOMY
(2022)
Article
Quantum Science & Technology
Haoyuan Cai, Qi Ye, Dong-Ling Deng
Summary: This article proves that physical quantum circuits can be learned through empirical risk minimization on a quantum computer, and provides valuable guidance for the development of quantum machine learning in both theory and practice.
QUANTUM SCIENCE AND TECHNOLOGY
(2022)
Article
Physics, Multidisciplinary
Wenjie Jiang, Zhide Lu, Dong-Ling Deng
Summary: Research shows that catastrophic forgetting also occurs in quantum machine learning. However, by utilizing the local geometric information in the loss function landscape of the trained model, a uniform method can be used to overcome this issue.
CHINESE PHYSICS LETTERS
(2022)
Article
Physics, Applied
Bichen Zhang, Swarnadeep Majumder, Pak Hong Leung, Stephen Crain, Ye Wang, Chao Fang, Dripto M. Debroy, Jungsang Kim, Kenneth R. Brown
Summary: In this paper, a method for reducing coherent errors by using hidden inverses is demonstrated. The effectiveness of this method is numerically simulated and experimentally validated on a trapped-ion quantum computer.
PHYSICAL REVIEW APPLIED
(2022)
Article
Multidisciplinary Sciences
Xu Zhang, Wenjie Jiang, Jinfeng Deng, Ke Wang, Jiachen Chen, Pengfei Zhang, Wenhui Ren, Hang Dong, Shibo Xu, Yu Gao, Feitong Jin, Xuhao Zhu, Qiujiang Guo, Hekang Li, Chao Song, Alexey Gorshkov, Thomas Iadecola, Fangli Liu, Zhe-Xuan Gong, Zhen Wang, Dong-Ling Deng, H. Wang
Summary: This paper reports the observation of a non-equilibrium state of matter, Floquet symmetry-protected topological phases, implemented through digital quantum simulation with programmable superconducting qubits. The researchers observe robust long-lived temporal correlations and subharmonic temporal response for the edge spins.
Article
Multidisciplinary Sciences
Huili Zhang, Si Jiang, Xin Wang, Wengang Zhang, Xianzhi Huang, Xiaolong Ouyang, Yefei Yu, Yanqing Liu, Dong-Ling Deng, L-M Duan
Summary: This study demonstrates the vulnerability of machine learning techniques in classifying phases of matter through experimental tests, highlighting the need for further investigation in this area.
NATURE COMMUNICATIONS
(2022)
Article
Physics, Applied
Mingyu Kang, Ye Wang, Chao Fang, Bichen Zhang, Omid Khosravani, Jungsang Kim, Kenneth R. Brown
Summary: This study develops filter functions for Molmer-Sorensen gates in trapped-ion quantum computers, accurately predicting the change in gate error due to small parameter fluctuations at any frequency. Experimental results show that using these filter functions can significantly improve gate fidelity in a five-ion chain.
PHYSICAL REVIEW APPLIED
(2023)
Article
Quantum Science & Technology
Zidu Liu, Pei-Xin Shen, Weikang Li, L-M Duan, Dong-Ling Deng
Summary: The researchers introduce a quantum capsule network (QCapsNet) with an efficient quantum dynamic routing algorithm, which shows enhanced performance and potential explainability compared to conventional quantum classifiers. This work has important implications for quantum machine learning and explainable quantum AI.
QUANTUM SCIENCE AND TECHNOLOGY
(2023)
Article
Quantum Science & Technology
Xiaoxuan Pan, Xi Cao, Weiting Wang, Ziyue Hua, Weizhou Cai, Xuegang Li, Haiyan Wang, Jiaqi Hu, Yipu Song, Dong-Ling Deng, Chang-Ling Zou, Re-Bing Wu, Luyan Sun
Summary: Quantum computer can boost machine learning through its inherent quantum parallelism. In the pursuit of quantum advantages for machine learning with noisy intermediate-scale quantum devices, an end-to-end learning model design approach was proposed, where the quantum ansatz is parameterized by directly manipulable control pulses without circuit design and compilation. Experimental realization of quantum end-to-end machine learning on a superconducting processor is reported. The trained model achieved 98% recognition accuracy for two handwritten digits (via two qubits) and 89% for four digits (via three qubits) in the MNIST database, demonstrating great potential for resolving complex real-world tasks when more qubits are available.
NPJ QUANTUM INFORMATION
(2023)
Article
Physics, Multidisciplinary
Weiyuan Gong, Si Jiang, Dong-Ling Deng
Summary: We prove that it is impossible to compile an arbitrary channel to arbitrary precision with any given finite elementary channel set, regardless of the length of the decomposition sequence. However, for a fixed error bound e, we propose a general and systematic strategy to decompose arbitrary quantum channels using an e-dependent universal set of elementary channels followed by a unitary gate. We further optimize this approach using proximal policy optimization and numerically evaluate its performance in topological compiling of Majorana fermions, showing effective reduction in the use of expensive elementary operations.
PHYSICAL REVIEW RESEARCH
(2023)
Article
Computer Science, Interdisciplinary Applications
Wenhui Ren, Weikang Li, Shibo Xu, Ke Wang, Wenjie Jiang, Feitong Jin, Xuhao Zhu, Jiachen Chen, Zixuan Song, Pengfei Zhang, Hang Dong, Xu Zhang, Jinfeng Deng, Yu Gao, Chuanyu Zhang, Yaozu Wu, Bing Zhang, Qiujiang Guo, Hekang Li, Zhen Wang, Jacob Biamonte, Chao Song, Dong-Ling Deng, H. Wang
Summary: Quantum computing can enhance machine learning and artificial intelligence, but quantum classifiers are susceptible to adversarial perturbations. Experimental demonstration using programmable superconducting qubits showed that adversarial training can significantly improve the classifiers' resistance to perturbations.
NATURE COMPUTATIONAL SCIENCE
(2022)
Article
Multidisciplinary Sciences
Weiyuan Gong, Dong-Ling Deng
Summary: This paper explores the universality of adversarial examples and perturbations for quantum classifiers, providing evidence and proofs for the existence of universal adversarial risk and adversarial perturbations. The vulnerability of quantum machine learning systems revealed in this study is crucial for the practical applications of near-term and future quantum technologies in solving machine learning problems.
NATIONAL SCIENCE REVIEW
(2022)
Article
Physics, Multidisciplinary
Dong Yuan, Shun-Yao Zhang, Yu Wang, Dong-Ling Deng
Summary: This study investigates the dynamics of quantum information scrambling in quantum many-body scarred systems, focusing on the PXP model. It is found that the out-of-time-ordered correlator (OTOC) and Holevo information exhibit linear light cone and periodic oscillations within the light cone for initial states within the scarred subspace. The results signify an unusual breakdown of quantum chaos.
PHYSICAL REVIEW RESEARCH
(2022)
Article
Multidisciplinary Sciences
Pengfei Wang, Junhua Zhang, Chun-Yang Luan, Mark Um, Ye Wang, Mu Qiao, Tian Xie, Jing-Ning Zhang, Adan Cabello, Kihwan Kim
Summary: In this study, the observation of quantum contextuality without detection, sharpness, and compatibility loopholes is reported. By adopting a hybrid two-ion system and highly efficient fluorescence measurements, the detection and sharpness loopholes are closed. The compatibility loophole is closed by targeting correlations between two different ions. The experimental results violate the bound for the most adversarial noncontextual models and provide a way to certify quantum systems.
Article
Physics, Multidisciplinary
Zidu Liu, L-M Duan, Dong-Ling Deng
Summary: Deep quantum neural networks provide a promising way to achieve a quantum learning advantage with noisy intermediate-scale quantum devices. This approach uses deep quantum feed-forward neural networks to represent the mixed states of open quantum many-body systems, and introduces a variational method with quantum derivatives to solve the dynamics and stationary states. The special structure of the quantum networks allows for efficient quantum analog of back-propagation algorithm, resource-saving reuse of hidden qubits, general applicability, and convenient implementation of symmetries.
PHYSICAL REVIEW RESEARCH
(2022)
