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quantum self-attention neural networks for text classification

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science China(information sciences) 2024年第4期67卷 301-313页

作者： Guangxi LI Xuanqiang ZHAO Xin WANG Institute for quantum Computing Baidu Research Centre for quantum Software and information University of Technology Sydney QICI quantum information and Computation Initiative Department of Computer ScienceThe University of Hong Kong Thrust of Artificial Intelligence Information HubHong Kong University of Science and Technology(Guangzhou)

An emerging direction of quantum computing is to establish meaningful quantum applications in various fields of artificial intelligence, including natural language processing(NLP). Although some efforts based on syntactic analysis have opened the door to research in quantum NLP(QNLP), limitations such as heavy syntactic preprocessing and syntax-dependent network architecture make them impracticable on larger and real-world data sets. In this paper, we propose a new simple network architecture, called the quantum selfattention neural network(QSANN), which can compensate for these limitations. Specifically, we introduce the self-attention mechanism into quantum neural networks and then utilize a Gaussian projected quantum self-attention serving as a sensible quantum version of self-attention. As a result, QSANN is effective and scalable on larger data sets and has the desirable property of being implementable on near-term quantum devices. In particular, our QSANN outperforms the best existing QNLP model based on syntactic analysis as well as a simple classical self-attention neural network in numerical experiments of text classification tasks on public data sets. We further show that our method exhibits robustness to low-level quantum noises and showcases resilience to quantum neural network architectures.

关键词： quantum neural networks self-attention natural language processing text classification parameterized quantum circuits

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Measuring small longitudinal phase shifts via weak measurement amplification

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Chinese Physics B 2024年第3期33卷 105-111页

作者：徐凯胡晓敏胡孟军王宁宁张超黄运锋柳必恒李传锋郭光灿张永生 CAS Key Laboratory of quantum information University of Science and Technology of ChinaHefei 230026China CAS Center For Excellence in quantum information and quantum Physics University of Science and Technology of ChinaHefei 230026China Hefei National Laboratory University of Science and Technology of ChinaHefei 230088China Beijing Academy of quantum information sciences Beijing 100193China

Weak measurement amplification,which is considered as a very promising scheme in precision measurement,has been applied to various small physical quantities *** many physical quantities can be converted into phase signals,it is interesting and important to consider measuring small longitudinal phase shifts by using weak ***,we propose and experimentally demonstrate a novel weak measurement amplification-based small longitudinal phase estimation,which is suitable for polarization *** realize one order of magnitude amplification measurement of a small phase signal directly introduced by a liquid crystal variable retarder and show that it is robust to the imperfection of ***,we analyze the effect of magnification error which is never considered in the previous works,and find the constraint on the *** results may find important applications in high-precision measurements,e.g.,gravitational wave detection.

关键词： weak measurement phase estimation quantum optics

Stimulated Brillouin interaction between guided phonons and photons in a lithium niobate waveguide

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science China(Physics,Mechanics & Astronomy) 2024年第1期67卷 173-175页

作者： Yuan-Hao Yang Jia-Qi Wang Zheng-Xu Zhu Xin-Biao Xu Qiang Zhang Juanjuan Lu Yu Zeng Chun-Hua Dong Luyan Sun Guang-Can Guo Chang-Ling Zou CAS Key Laboratory of quantum information University of Science and Technology of ChinaHefei 230026China CAS Center for Excellence in quantum information and quantum Physics University of Science and Technology of ChinaHefei 230026China Key Laboratory of quantum Optics and quantum Optics Devices Institute of Opto-ElectronicsShanxi UniversityTaiyuan 030006China School of information science and Technology ShanghaiTech UniversityShanghai 201210China Center for quantum information Institute for Interdisciplinary Information SciencesTsinghua UniversityBeijing 100084China

The Brillouin scattering is one of the strongest nonlinear optical effects in dielectrics[1].In particular,the backward Brillouin scattering(BBS)provides an efficient method to achieve low-noise optical gain for active photonics[2]and the coherent interconnects between 10 GHz phonons and photons[3].However,previous studies on BBS are primarily limited to the unconfined phonons[1]or phonon confined in suspended structures[4-6].

关键词： scattering waveguide Brillouin

Maxwell Demon and Einstein–Podolsky–Rosen Steering

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Chinese Physics Letters 2024年第5期41卷 12-16页

作者：胡孟军胡晓敏张永生 Beijing Academy of quantum information sciences Beijing 100193China Laboratory of quantum information University of Science and Technology of ChinaHefei 230026China Synergetic Innovation Center of quantum information and quantum Physics University of Science and Technology of ChinaHefei 230026China Hefei National Laboratory University of Science and Technology of ChinaHefei 230088China

Research of Maxwell demon and quantum entanglement is important because of its foundational significance in physics and its potential applications in quantum information. Previous studies on the Maxwell demon have primarily focused on thermodynamics, taking into account quantum correlations. Here we consider from another perspective and ask whether quantum non-locality correlations can be simulated by performing work. The Maxwell demon-assisted Einstein–Podolsky–Rosen(EPR) steering is thus proposed, which implies a new type of loophole. The application of Landauer's erasure principle suggests that the only way to close this loophole during a steering task is by continuously monitoring the heat fluctuation of the local environment by the *** construct a quantum circuit model of Maxwell demon-assisted EPR steering, which can be demonstrated by current programmable quantum processors, such as superconducting quantum computers. Based on this quantum circuit model, we obtain a quantitative formula describing the relationship between energy dissipation due to the work of the demon and quantum non-locality correlation. The result is of great physical interest because it provides a new way to explore and understand the relationship between quantum non-locality, information, and thermodynamics.

关键词： quantum Maxwell Einstein

Breaking the efficiency limitations of dissipative Kerr solitons using nonlinear couplers

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science China(Physics,Mechanics & Astronomy) 2024年第3期67卷 88-94页

作者： Ming Li Xiao-Xiao Xue Yan-Lei Zhang Xin-Biao Xu Chun-Hua Dong Guang-Can Guo Chang-Ling Zou CAS Key Laboratory of quantum information University of Science and Technology of ChinaHefei 230026China CAS Centerfor Excellence in quantum information and quantum Physics University of Science and Technology of ChinaHefei 230026China Department of Electronic Engineering Beijing National Research Center for Information Science and TechnologyTsinghua University Beijing 100084China

Dissipative Kerr solitons(DKS) have long been suffering from poor power conversion efficiency when driven by continuous-wave lasers. By deriving the critical coupling condition of a multimode nonlinear optics system in a generalized theoretical framework,two efficiency limitations of the conventional pump method of DKS are revealed: the effective coupling rate is too small and is also power-dependent. A general approach is provided to resolve this challenge by introducing two types of nonlinear couplers to couple the soliton cavity and CW input through nonlinear processes. The collective coupler opens multiple coupling channels and the self-adaptive coupler builds a power-independent effective external coupling rate to the DKS for approaching the generalized critical coupling condition, which promises near-unity power conversion efficiencies. For instance, a conversion efficiency exceeding 90% is predicted for aluminum nitride microrings with a nonlinear coupler utilizing second-harmonic generation. The mechanism applies to various nonlinear processes, including Raman and Brillouin scattering, and thus paves the way for micro-solitons toward practical applications.

关键词： Kerr frequency comb conversion efficiency nonlinear coupler

Proposal for sequential Stern-Gerlach experiment with programmable quantum processors

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Chinese Physics B 2024年第2期33卷 131-136页

作者：胡孟军缪海兴张永生 Beijing Academy of quantum information sciences Beijing 100193China State Key Laboratory of Low Dimensional quantum Physics Department of PhysicsTsinghua UniversityBeijing 100084China Laboratory of quantum information University of Science and Technology of ChinaHefei 230026China Synergetic Innovation Center of quantum information and quantum Physics University of Science and Technology of ChinaHefei 230026China Hefei National Laboratory University of Science and Technology of ChinaHefei 230088China

The historical significance of the Stern–Gerlach(SG)experiment lies in its provision of the initial evidence for space *** time,its sequential form has evolved into an elegant paradigm that effectively illustrates the fundamental principles of quantum *** date,the practical implementation of the sequential SG experiment has not been fully *** this study,we demonstrate the capability of programmable quantum processors to simulate the sequential SG *** specific parametric shallow quantum circuits,which are suitable for the limitations of current noisy quantum hardware,are given to replicate the functionality of SG devices with the ability to perform measurements in different ***,it has been demonstrated that Wigner’s SG interferometer can be readily implemented in our sequential quantum *** the utilization of the identical circuits,it is also feasible to implement Wheeler’s delayed-choice *** propose the utilization of cross-shaped programmable quantum processors to showcase sequential experiments,and the simulation results demonstrate a strong alignment with theoretical *** the rapid advancement of cloud-based quantum computing,such as BAQIS Quafu,it is our belief that the proposed solution is well-suited for deployment on the cloud,allowing for public *** findings not only expand the potential applications of quantum computers,but also contribute to a deeper comprehension of the fundamental principles underlying quantum theory.

关键词： sequential Stern-Gerlach quantum circuit quantum processor

Security analysis of satellite-to-ground reference-frame-independent quantum key distribution with beam wandering

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Chinese Physics B 2024年第8期33卷 192-201页

作者：周淳赵燕美杨晓亮陆宜飞周雨姜晓磊汪海涛汪洋李家骥江木生汪翔张海龙李宏伟鲍皖苏 Henan Key Laboratory of quantum information and Cryptography SSF IEUZhengzhou 450001China Synergetic Innovation Centre of quantum information and quantum Physics University of Science and Technology of ChinaHefei 230026China

The reference-frame-independent(RFI)quantum key distribution(QKD)is suitable for satellite-based links by removing the active alignment on the reference ***,how the beam wandering influences the performance of RFI-QKD remains a pending issue in satellite-to-ground *** this paper,based on the mathematical model for characterizing beam wandering,we present the security analysis for satellite-to-ground RFI-QKD and analytically derive formulas for calculating the secret key rate with beam *** simulation results show that the performance of RFI-QKD is better than the Bennett–Brassard 1984(BB84)QKD with beam wandering in asymptotic ***,the degree of influences of beam wandering is specifically presented for satellite-to-ground RFI-QKD when statistical fluctuations are taken into *** work can provide theoretical support for the realization of RFI-QKD using satellite-to-ground links and have implications for the construction of large-scale satellite-based quantum networks.

关键词： quantum key distribution satellite-to-ground beam wandering

Quantized anomalous Hall resistivity achieved in molecular beam epitaxy-grown Mn Bi2Te4 thin films

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National science Review 2024年第2期11卷 24-32页

作者： Yunhe Bai Yuanzhao Li Jianli Luan Ruixuan Liu Wenyu Song Yang Chen Peng-Fei Ji Qinghua Zhang Fanqi Meng Bingbing Tong Lin Li Yuying Jiang Zongwei Gao Lin Gu Jinsong Zhang Yayu Wang Qi-Kun Xue Ke He Yang Feng Xiao Feng State Key Laboratory of Low Dimensional quantum Physics Department of Physics Tsinghua University Institute of Physics Chinese Academy of Sciences School of Materials science and Engineering Tsinghua University Beijing Academy of quantum information sciences Frontier science Center for quantum information Hefei National Laboratory Southern University of science and Technology

The intrinsic magnetic topological insulator MnBi2Te4provides a feasible pathway to the high-temperature quantum anomalous Hall（QAH） effect as well as various novel topological quantum phases. Although quantized transport properties have been observed in exfoliated MnBi2Te4thin flakes, it remains a big challenge to achieve molecular beam epitaxy（MBE）-grown MnBi2Te4thin films even close to the quantized regime. In this work, we report the realization of quantized anomalous Hall resistivity in MBE-grown MnBi2Te4thin films with the chemical potential tuned by both controlled in situ oxygen exposure and top gating. We find that elongated post-annealing obviously elevates the temperature to achieve quantization of the Hall resistivity, but also increases the residual longitudinal resistivity, indicating a picture of high-quality QAH puddles weakly coupled by tunnel barriers. These results help to clarify the puzzles in previous experimental studies on MnBi2Te4and to find a way out of the big difficulty in obtaining MnBi2Te4samples showing quantized transport properties.

关键词： intrinsic magnetic topological insulator quantized anomalous Hall resistivity molecular beam epitaxy quantized transport property

General Method of Combining Grover and Simon for Attacking Block Ciphers

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China Communications 2024年第6期21卷 237-245页

作者： Fu Xiangqun Bao Wansu Shi Jianhong Li Tan Henan Key Laboratory of quantum information and Cryptography PLA SSF IEUZhengzhou 450001China Synergetic Innovation Center of quantum information and quantum Physics University of Science and Technology of ChinaHefei 230026China

The compatibility of different quantum algorithms should be considered when these algorithms are *** this paper,the method of combining Grover and Simon is studied for the first time,under some preconditions or ***,we give two preconditions of applying Grover’s algorithm,which ensure that the success probability of finding the marked element is close to ***,based on these two preconditions,it is found out that the success probability of the quantum algorithm for FXconstruction is far less than ***,we give the design method of the Oracle function,and then present the general method of combining Grover and Simon algorithm for attacking block ciphers,with success probability close to 1.

关键词： block ciphers post-quantum crypto quantum algorithms