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Communications in Theoretical Physics 2014年第9期61卷 430-442页

作者： H.R.Baghshahi M.K.Tavassoly A.Behjat Atomic and Molecular Group Faculty of Physics Yazd University Department of Physics Faculty of Science Vali-e-Asr University of Rafsanjan The laboratory of quantum information processing Yazd University Photonics Research Group Engineering Research Center Yazd University

The interaction between a◇-type four-level atom and a single-mode field in the presence of Kerr medium with intensity-dependent coupling involving multi-photon processes has been studied. Using the generalized(nonlinear)Jaynes–Cummings model, the exact analytical solution of the wave function for the considered system under particular condition, has been obtained when the atom is initially excited to the topmost level and the field is in a coherent state. Some physical properties of the atom-field entangled state such as linear entropy showing the entanglement degree, Mandel parameter, mean photon number and normal squeezing of the resultant state have been calculated. The effects of Kerr medium, detuning and the intensity-dependent coupling on the temporal behavior of the latter mentioned nonclassical properties have been investigated. It is shown that by appropriately choosing the evolved parameters in the interaction process, each of the above nonclassicality features, which are of special interest in quantum optics as well as quantum information processing, can be revealed.

关键词： Jaynes–Cummings model intensity-dependent coupling Kerr medium entanglement Mandel parameter squeezing

A new route to associating ultracold polar molecules in the absolute ground state

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Science China(Physics,Mechanics & Astronomy) 2023年第11期66卷 235-236页

作者： Jun Rui Shanghai Research Center for quantum Science CAS Center for Excellence in Quantum Information and Quantum PhysicsUniversity of Science and Technology of ChinaShanghai201315China Hefei National laboratory University of Science and Technology of ChinaHefei230088China

Ultracold polar molecules have emerged as a new research frontier in quantum physics and chemistry[1].These molecules exhibit rich internal rotational,vibrational,and electronic levels,providing new resources for quantum control and quantum *** intrinsic permanent electric dipole moment of polar molecules enables the strong longrange and anisotropic dipole-dipole interaction between spatially displaced molecules and constitutes a valuable tool for simulating novel long-range many-body physics and processing quantum information.

关键词： quantum dipole polar

Controllable microwave frequency comb generation in a tunable superconducting coplanar-waveguide resonator

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Chinese Physics B 2021年第4期30卷 591-595页

作者： Shuai-Peng Wang Zhen Chen Tiefu Li quantum Physics and quantum information Division Beijing Computational Science Research CenterBeijing 100193China Institute of Microelectronics Tsinghua UniversityBeijing 100084China Beijing Academy of quantum information Sciences Beijing 100193China Frontier Science Center for quantum information Beijing 100084China

Frequency combs are useful in a wide range of applications,such as optical metrology and high-precision *** experimentally study a controllable frequency comb generated in a tunable superconducting coplanarwaveguide resonator in the microwave regime.A two-tone drive is applied on one of the resonance modes of the resonator and comb generation is observed around the resonance frequency of the *** central frequency and teeth density of the comb are precisely controllable,and the teeth spacing can be adjusted from Hz to ***,we show that a few hundreds of sidebands can be generated using a sufficiently strong drive power and the weakest drive power needed to generate the comb can be reduced to approach the quantum *** experimental results can be qualitatively explained via theoretical analysis.

关键词： superconducting circuit SQUID microwave frequency comb

First-principles design of spintronics materials

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National Science Review 2016年第3期3卷 365-381页

作者： Xingxing Li Jinlong Yang Hefei National laboratory for Physical Sciences at the Microscale University of Science and Technology of China Synergetic Innovation Center of quantum information& quantum Physics University of Science and Technology of China

Spintronics is one of the most promising next generation information technology, which uses the spins of electrons as information carriers and possesses potential advantages of speeding up data processing, high circuit integration density, and low energy consumption. However, spintronics faces a number of challenges, including spin generation and injection, long distance spin transport, and manipulation and detection of spin orientation. In solving these issues, new concepts and spintronics materials were proposed one after another, such as half metals, spin gapless semiconductors, and bipolar magnetic *** insulators can also be viewed as a special class of spintronics materials, with their surface states used for pure spin generation and transportation. In designing these spintronics materials, first-principles calculations play a very important role. This article attempts to give a brief review of the basic principles and theoretical design of these materials. Meanwhile, we also give some attentions to the antiferromagnetic spintronics, which is mainly based on antiferromagnets and has aroused much interest in recent years.

关键词： spintronics antiferromagnetic spintronics half metals magnetic semiconductors topological insulators

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

Energy-Efficient Bandwidth and Power Allocation in Relay-Assisted Multi-Layer Heterogeneous Networks with Energy Harvesting

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Journal of Shanghai Jiaotong university(Science) 2023年第6期28卷 822-830页

作者：高锦程赵宜升陈加法陈忠辉 Fujian Key laboratory for Intelligent processing and Wireless Transmission of Media information College of Physics and Information EngineeringFuzhou UniversityFuzhou 350108China

Aiming at excessive users existing in a pico base station(PBS)in the multi-layer heterogeneous networks,the resource allocation problem of maximizing the energy efficiency of the networks is investigated in this *** deploying a relay node with energy harvesting function,the data of some users in the PBS can be transferred to an adjacent idle *** bandwidth and transmitting power of users and the relay node are both considered to formulate the resource allocation optimization *** objective is to maximize the energy eficiency of the whole heterogeneous networks under the constraints of the user's minimum data rate and energy *** suboptimal solution is obtained by using the particle swarm optimization(PSO)algorithm and quantum-behaved particle swarm optimization(QPSO)*** results show that the adopted methods have higher energy efficiency than the conventional fixed power and bandwidth *** addition,the time complexity of the adopted methods is relatively low.

关键词： energy harvesting heterogeneous networks energy efficiency

Correction of microwave pulse reflection by digital filters in superconducting quantum circuits

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Chinese Physics B 2024年第9期33卷 117-123页

作者： Liang-Liang Guo Peng Duan Lei Du Hai-Feng Zhang Hao-Ran Tao Yong Chen Xiao-Yan Yang Chi Zhang Zhi-Long Jia Wei-Cheng Kong Zhao-Yun Chen Guo-Ping Guo CAS Key laboratory of quantum information University of Science and Technology of ChinaHefei 230026China CAS Center for Excellence and Synergetic Innovation Center in quantum information and quantum Physics University of Science and Technology of ChinaHefei 230026China Origin quantum Computing Company Limited Hefei 230088China Institute of Artificial Intelligence Hefei Comprehensive National Science CenterHefei 230088China

Reducing the control error is vital for high-fidelity digital and analog quantum *** superconducting circuits,one disagreeable error arises from the reflection of microwave signals due to impedance mismatch in the control ***,we demonstrate a reflection cancelation method when considering that there are two reflection nodes on the control *** propose to generate the pre-distortion pulse by passing the envelopes of the microwave signal through digital filters,which enables real-time reflection correction when integrated into the field-programmable gate array(FPGA).We achieve a reduction of single-qubit gate infidelity from 0.67%to 0.11%after eliminating microwave ***-time correction of microwave reflection paves the way for precise control and manipulation of the qubit state and would ultimately enhance the performance of algorithms and simulations executed on quantum processors.

关键词： reflection cancelation digital filter single-qubit gate superconducting circuit

Contrasting room-temperature hydrogen sensing capabilities of Pt-SnO2 and Pt-TiO2 composite nanoceramics

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Nano Research 2016年第11期9卷 3528-3535页

作者： Yao Xiong Wanping Chen Yesheng Li Ping Cui Shishang Guo Wei Chen Zilong Tang Zijie Yan Zhenyu Zhang School of Physics and Technology Wuhan University Wuhan 430072 China School of Materials Science and Engineering State Key Laboratory of New Ceramics and Fine Processing Tsinghua University Beijing 100084 China International Center for quantum Design of Functional Materials (ICQD) Hefei Laboratory for Physical Sciences at Microscale (HFNL) and Synergetic Innovation Center of Notional Quantum Information and Quantum Physics University of Science and Technology of China Hefei 230026 China Department of Chemical and Biomolecular Engineering Clarkson University Potsdam New York 13699 USA

Contrasting room-temperature hydrogen sensing behaviors have been revealed for Pt-TiO2 and Pt-SnO2 composite nanoceramics. In the case of the Pt-TiO2 nanoceramics, the ultrahigh hydrogen sensitivities are lost abruptly when the oxygen/hydrogen concentration ratio in ambient atmosphere reaches a critical value. However, in the case of the Pt-SnO2 nanoceramics, such a phenomenon does not occur, and the extraordinary room-temperature hydrogen sensing capabilities are observed in the presence of oxygen in air. Our combined experimental and theoretical investigations establish a unified mechanism for both the systems, which is rooted in hydrogen chemisorption on the surface and interstitial lattice sites of SnO2 and TiO2; the difference in stability of the chemisorbed hydrogen on SnO2 and TiO2 is considered responsible for the contrasting hydrogen sensing capabilities. The central findings are helpful in enriching our microscopic understanding of hydrogen interaction with various metal oxide semiconductors （MOSs） at room temperature in varying mixed gaseous concentrations, and they could be instrumental in developing reliable room-temperature hydrogen sensors based on bulk MOSs.

关键词： Sn02 nanoceramics sensors hydrogen room-temperature

Delayed error verification in quantum key distribution

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Chinese Science Bulletin 2014年第23期59卷 2825-2828页

作者： Chun-Mei Zhang Xiao-Tian Song Patcharapong Treeviriyanupab Mo Li Chao Wang Hong-Wei Li Zhen-Qiang Yin Wei Chen Zheng-Fu Han Key laboratory of quantum information CASUniversity of Science and Technology of China Synergetic Innovation Center of quantum information and quantum Physics University of Science and Technology of China Department of Computer Science Faculty of Science and TechnologyPhranakhon Rajabhat University

quantum key distribution(QKD)provides an unconditional secure key generation method between two distant legitimate parties Alice and Bob based on the fundamental properties of quantum mechanics,in the presence of an eavesdropper *** key reconciliation cannot always assure that the reconciled keys between Alice and Bob are identical,error verification is an important step in *** this paper,we propose a scheme of delayed error verification using extra keys gained by privacy amplification with an arbitrarily small failure *** proposed scheme simplifies the post-processing procedure in QKD,which can be applied in practical QKD systems.

关键词：量子密钥分配误差检定延迟量子密钥分发无条件安全生成方法量子力学误差校验

Effects of quantum noise on teleportation of arbitrary two-qubit state via five-particle Brown state

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Chinese Physics B 2024年第8期33卷 204-211页

作者：汪澳魏玉震姜敏李泳成陈虹黄旭 School of Electronics&information Engineering Soochow UniversitySuzhou 215006China Key laboratory of System Control and information processing Ministry of EducationShanghai 200240China School of information Engineering Huzhou UniversityHuzhou 313000China

We propose a new protocol for quantum teleportation(QT)which adopts the Brown state as the quantum *** work focuses on the teleportation of a single unknown two-qubit state via a Brown state channel in an ideal *** validate the effectiveness of our proposed scheme,we conduct experiments by using the quantum circuit simulator ***,we investigate the effects of four noisy channels,namely,the phase damping noise,the bit-flip noise,the amplitude damping noise,and the phase-flip ***,we employ Monte Carlo simulation to elucidate the fidelity density under various noise *** analysis demonstrates that the fidelity of the protocol in a noisy environment is influenced significantly by the amplitude of the initial state and the noise factor.

关键词： quantum communication Brown state fidelity