Article
Multidisciplinary Sciences
Xiaodong Yang, Xi Chen, Jun Li, Xinhua Peng, Raymond Laflamme
Summary: This study introduces a quantum metrology scheme that does not require complex offline design and can automatically optimize controls online, improving measurement precision. Successful experimental demonstration was conducted on a nuclear magnetic resonance processor.
SCIENTIFIC REPORTS
(2021)
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)
Review
Automation & Control Systems
Xiaozhen Ge, Re-Bing Wu, Herschel Rabitz
Summary: This review explores the landscapes of hybrid quantum-classical optimization algorithms prevalent in rapidly developing quantum technologies. It discusses how the objective function is computed by a quantum system while the optimizer is classical. The review shows that the landscape's geometry undergoes morphological changes from trap-free to rugged landscapes, eventually leading to barren-plateau landscapes where the optimizer can hardly move. This unified view is crucial for understanding different systems and finding ways to avoid traps or plateaus.
ANNUAL REVIEWS IN CONTROL
(2022)
Article
Quantum Science & Technology
Toru Aonishi, Kazushi Mimura, Masato Okada, Yoshihisa Yamamoto
Summary: A quantum-classical hybrid system is proposed for optimization in L0-regularization-based compressed sensing, potentially outperforming L1-regularization-based compressed sensing. The system utilizes a coherent Ising machine as the quantum machine and shows promising theoretical performance close to the limit of compressed sensing, surpassing L1-RBCS in estimation accuracy in practical applications such as magnetic resonance imaging data analysis.
QUANTUM SCIENCE AND TECHNOLOGY
(2022)
Article
Thermodynamics
Wei Fu, Haipeng Xie, Hao Zhu, Hefeng Wang, Lizhou Jiang, Chen Chen, Zhaohong Bie
Summary: Incorporating multiple resilient resources into coordinated post-disaster restoration strategy contributes positively to resilience enhancement of power distribution systems. However, considering multiple factors may increase model complexity, resulting in longer solution times and compromised practicality. This paper proposes a hybrid quantum-classical algorithm to address this problem and verifies its effectiveness and computational efficiency.
Article
Computer Science, Hardware & Architecture
Hyeokjea Kwon, Joonwoo Bae
Summary: This article presents a scheme to mitigate errors in measurement readout with NISQ devices by dealing with unknown quantum noise, which is implemented in two quantum algorithms and shows an enhancement in the statistics of measurement outcomes for both algorithms using NISQ devices.
IEEE TRANSACTIONS ON COMPUTERS
(2021)
Article
Physics, Multidisciplinary
Junhua Liu, Kwan Hui Lim, Kristin L. Wood, Wei Huang, Chu Guo, He-Liang Huang
Summary: The study introduces a hybrid quantum-classical convolutional neural network that can efficiently perform feature mapping on noisy intermediate-scale quantum computers, proposes a framework for automatic computation of loss function gradients, and demonstrates the architecture's potential in surpassing classical CNN in learning accuracy for classification tasks.
SCIENCE CHINA-PHYSICS MECHANICS & ASTRONOMY
(2021)
Article
Computer Science, Artificial Intelligence
Samuel Yen-Chi Chen, Chih-Min Huang, Chia-Wei Hsing, Ying-Jer Kao
Summary: The hybrid model combines a quantum-inspired tensor network and a variational quantum circuit for supervised learning tasks, allowing simultaneous training of classical and quantum parts. It outperforms principal component analysis as a feature extractor in binary and ternary classification of MNIST and Fashion-MNIST datasets. The architecture is highly adaptable, with the classical-quantum boundary adjustable based on quantum resource availability.
MACHINE LEARNING-SCIENCE AND TECHNOLOGY
(2021)
Article
Automation & Control Systems
Esmaeil Sharifi, Christopher J. Damaren
Summary: This paper presents a novel optimal control design framework for hybrid nonlinear dynamical systems, proposing two numerical algorithms to approximate the continuous-time and discrete-time portions of the hybrid Hamilton-Jacobi-Bellman equation. By combining Galerkin's spectral method and spectral collocation method, the desired hybrid nonlinear optimal control law is obtained, with illustrative examples provided to evaluate its functionality.
INTERNATIONAL JOURNAL OF CONTROL
(2021)
Article
Quantum Science & Technology
Samuel Fernandez-Lorenzo, Diego Porras, Juan Jose Garcia-Ripoll
Summary: The work presents tools for addressing combinatorial optimization problems with a cardinality constraint, including a new heuristic pruning method and analysis of using soft constraints to control the number of non-zero variables. The power of both techniques is illustrated through the index tracking problem, with a comparison of different state-of-the-art quantum variational optimization algorithms in the pruning method.
QUANTUM SCIENCE AND TECHNOLOGY
(2021)
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
A. R. Ramos Ramos, O. Kuehn
Summary: This study introduces a direct optimal control method for optimizing wavepacket dynamics by solving a nonlinear optimization problem, providing meaningful conditions for field optimization.
FRONTIERS IN PHYSICS
(2021)
Article
Quantum Science & Technology
Nicola Mariella, Sergiy Zhuk
Summary: Swap mapping is a quantum compiler optimization that uses SWAP gates to map a logical quantum circuit to a physically implementable one. The placement of SWAP gates is a discrete optimization process that ensures hardware connectivity constraints are met.
QUANTUM INFORMATION PROCESSING
(2023)
Article
Computer Science, Information Systems
Xiaodie Lin, Zhaohui Wei, Penghui Yao
Summary: This paper investigates two-stage hybrid protocols that combine quantum and classical resources to generate classical correlations shared by two separated players. The motivation behind the research is twofold: first, to enhance the capability of quantum schemes when quantum resources are insufficient, extra classical resources can be introduced; second, the paper provides new insights into the advantage of sharing prior quantum entanglement over sharing prior randomness, a fundamental open problem in communication complexity theory.
IEEE TRANSACTIONS ON INFORMATION THEORY
(2022)
Article
Physics, Multidisciplinary
Alessandro Sergi, Daniele Lamberto, Agostino Migliore, Antonino Messina
Summary: The conceptual analysis of quantum mechanics reveals that a theory consistent with observations should be capable of describing both quantum and classical systems, known as quantum-classical hybrids. We extended the Ehrenfest theorem to bipartite quantum systems and used a formalism based on operator-valued Wigner functions and quantum-classical brackets to study quantum-classical hybrids. Our results show that the time variation of the average energy of each component in a bipartite system is equal to the average of the symmetrized quantum dissipated power in both quantum and quantum-classical cases. These theoretical findings are expected to be valuable for analyzing quantum-classical hybrids and developing self-consistent numerical algorithms for Ehrenfest-type simulations.
Article
Physics, Applied
Shiming Song, Min Jiang, Yushu Qin, Yu Tong, Wenzhe Zhang, Xi Qin, Ren-Bao Liu, Xinhua Peng
Summary: This study demonstrates a spin-noise spectroscopic approach to investigate collision phenomena. By measuring optical polarization rotation noise, the approach provides a tool to observe collision-sensitive spin noise and determine key collision parameters.
PHYSICAL REVIEW APPLIED
(2022)
Article
Quantum Science & Technology
Ran Liu, Yu Chen, Min Jiang, Xiaodong Yang, Ze Wu, Yuchen Li, Haidong Yuan, Xinhua Peng, Jiangfeng Du
Summary: The study introduces a critical quantum metrology technique using an adiabatic scheme on a first-order quantum phase transition, encoding an unknown parameter and tuning the energy gap by introducing a small transverse magnetic field. Experimental implementation using nuclear magnetic resonance techniques shows high precision achieving Heisenberg scaling at the critical point.
NPJ QUANTUM INFORMATION
(2021)
Article
Quantum Science & Technology
Zhe Ding, Ran Liu, Chandrashekar Radhakrishnan, Wenchao Ma, Xinhua Peng, Ya Wang, Tim Byrnes, Fazhan Shi, Jiangfeng Du
Summary: Quantum coherence is the most fundamental quantifier in quantum physics, with local and global coherence existing in different ways and exhibiting a trade-off relation. Experimental studies have shown that coherence and monogamy have equivalent properties, demonstrating the utility of coherence as a characterization tool for quantum states.
NPJ QUANTUM INFORMATION
(2021)
Article
Physics, Multidisciplinary
Min Jiang, Yushu Qin, Xin Wang, Yuanhong Wang, Haowen Su, Xinhua Peng, Dmitry Budker
Summary: This study investigates the amplification of magnetic-field signals using periodically driven Xe-129 spins and observes signal amplification at frequencies of transitions between Floquet spin states. The findings enable simultaneous enhancement and measurement of multiple magnetic fields with at least one order of magnitude improvement, offering the capability of femtotesla-level measurements.
PHYSICAL REVIEW LETTERS
(2022)
Article
Quantum Science & Technology
Zidong Lin, Lin Zhang, Xinyue Long, Yu-ang Fan, Yishan Li, Kai Tang, Jun Li, XinFang Nie, Tao Xin, Xiong-Jun Liu, Dawei Lu
Summary: In this experiment, we perform a quantum simulation of the two-dimensional non-Hermitian quantum anomalous Hall model using a nuclear magnetic resonance processor. We develop a stochastic average approach based on the stochastic Schrodinger equation to realize the non-Hermitian dissipative quantum dynamics. The experiment demonstrates the stability of dynamical topology against weak noise and observes two types of dynamical topological transitions driven by strong noise, as well as a region where the emergent topology is always robust regardless of the noise strength.
NPJ QUANTUM INFORMATION
(2022)
Article
Physics, Multidisciplinary
Xinfang Nie, Xuanran Zhu, Keyi Huang, Kai Tang, Xinyue Long, Zidong Lin, Yu Tian, Chudan Qiu, Cheng Xi, Xiaodong Yang, Jun Li, Ying Dong, Tao Xin, Dawei Lu
Summary: Indefinite causal order (ICO) plays a crucial role in quantum technologies, and this study focuses on quantum thermodynamics and the performance evaluation of ICO refrigerator. By proposing the density matrix exponentiation (DME) approach, the coefficient of performance (COP) is significantly enhanced.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Applied
Xiaodong Yang, Yunrui Ge, Bo Zhang, Jun Li
Summary: This study investigates the combination of dynamical decoupling and robust optimal control for high-fidelity control of quantum systems. By using robust optimal control to find robust control pulses and incorporating them into dynamical decoupling sequences, a remarkable improvement in robustness against multiple error channels is achieved.
PHYSICAL REVIEW APPLIED
(2022)
Article
Multidisciplinary Sciences
Yuanhong Wang, Ying Huang, Chang Guo, Min Jiang, Xiang Kang, Haowen Su, Yushu Qin, Wei Ji, Dongdong Hu, Xinhua Peng, Dmitry Budker
Summary: Quantum sensing offers sensitive tools for searching for exotic spin-dependent interactions beyond the standard model. This study develops a technique called SAPPHIRE to resonantly search for parity-odd spin-spin interactions with an effective amplification factor of about 200. The results set stringent constraints on axial-vector electron-neutron couplings and explore a previously unexplored parameter space for axial-vector couplings between nucleons. These findings complement existing astrophysical and laboratory studies on potential standard model extensions.
Article
Physics, Applied
Yifan Zhang, Hao Wu, Xiaodong Yang, Tianyu Xie, Ye-Xin Wang, Chang Liu, Qing Zhao, Jiyang Ma, Jun Li, Bo Zhang
Summary: Noise-resilient quantum gates designed with robust optimal control (ROC) algorithms are experimentally demonstrated using nitrogen-vacancy centers in diamond, achieving tailored robustness against detunings and Rabi errors simultaneously. With 10% off-resonance detuning and 10% deviation of a Rabi frequency, an average single-qubit gate fidelity of up to 99.89% is achieved. ROC-based multipulse quantum sensing sequences can also suppress spurious responses caused by finite widths and imperfections of microwave pulses, enhancing the performance of existing multipulse quantum sensing sequences.
PHYSICAL REVIEW APPLIED
(2023)
Article
Optics
Yue Zhai, Xiaodong Yang, Kai Tang, Xinyue Long, Xinfang Nie, Tao Xin, Dawei Lu, Jun Li
Summary: Quantum metrology aims to improve parameter estimation precision using suitable quantum resources, but realistic noises can severely distort the predicted precision. To address this issue, we propose a control-enhanced quantum metrology scheme that can automatically adjust the parameter-encoding dynamics to mitigate the effects of noises, leading to optimal resultant states. Numerical simulations and a proof-of-principle experiment in a nuclear magnetic resonance system demonstrate that our scheme outperforms the standard scheme and the ancilla-assisted scheme, improving the estimation precision by approximately one order of magnitude. This research is significant for harnessing the power of quantum metrology in realistic noise environments.
Article
Optics
Xiaodong Yang, Xinfang Nie, Yunlan Ji, Tao Xin, Dawei Lu, Jun Li
Summary: This paper presents a method for optimizing quantum control design using Trotter decomposition. By substituting time evolution segments with their Trotter decompositions, the computational speed can be significantly improved while maintaining an acceptable level of propagator error. Experimental results demonstrate that this strategy leads to performance improvements in gradient ascent pulse engineering and variational quantum algorithms, and it is applicable to many other quantum optimization and simulation tasks.
Article
Optics
Yunlan Ji, Feifei Zhou, Xi Chen, Ran Liu, Zhaokai Li, Hui Zhou, Xinhua Peng
Summary: In this study, a counterdiabatic (CD) scheme for rapid and high-fidelity transfer of quantum state across a one-dimensional spin chain is proposed. By optimizing the control couplings, the resulting scheme allows a significant increase in state-transfer fidelity in a short time compared to traditional adiabatic protocols, and it demonstrates robustness against imperfections in control fields and evolution time.
Article
Optics
Ze Zhang, Xinyue Long, Xiuzhu Zhao, Zidong Lin, Kai Tang, Hongfeng Liu, Xiaodong Yang, Xinfang Nie, Jiansheng Wu, Jun Li, Tao Xin, Keren Li, Dawei Lu
Summary: This paper proposes a method based on quantum scattering circuit to directly and efficiently measure the modular transformation matrix of topological orders. The method is successfully implemented in a nuclear magnetic resonance quantum simulator to simulate both Abelian and non-Abelian topological orders. This work opens up new possibilities for studying topological orders in circuit-based quantum simulators.
