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Room-Temperature Implementation of the Deutsch-Jozsa Algorithm with a Single Electronic Spin in Diamond

Physical Review Letters 2010年第4期105卷 040504-040504页

作者： Fazhan Shi Xing Rong Nanyang Xu Ya Wang Jie Wu Bo Chong Xinhua Peng Juliane Kniepert Rolf-Simon Schoenfeld Wolfgang Harneit Mang Feng Jiangfeng Du Hefei National Laboratory for Physics Sciences at Microscale and Department of Modern Physics University of Science and Technology of China Hefei 230026 China Institut für Experimentalphysik Freie Universität Berlin Arnimallee 14 14195 Berlin Germany State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics Wuhan Institute of Physics and Mathematics Chinese Academy of Sciences Wuhan 430071 China

The nitrogen-vacancy defect center (N−V center) is a promising candidate for quantum information processing due to the possibility of coherent manipulation of individual spins in the absence of the cryogenic requirement. We report a room-temperature implementation of the Deutsch-Jozsa algorithm by encoding both a qubit and an auxiliary state in the electron spin of a single N−V center. By thus exploiting the specific S=1 character of the spin system, we demonstrate how even scarce quantum resources can be used for test-bed experiments on the way towards a large-scale quantum computing architecture.

关键词： Room temperature

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Self-powered solar-blind photodiodes based on EFG-grown(100)-dominant β-Ga_(2)O_(3) substrate

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Chinese physics B 2021年第1期30卷 483-486页

作者： Xu-Long Chu Zeng Liu Yu-Song Zhi Yuan-Yuan Liu Shao-Hui Zhang Chao Wu Ang Gao Pei-Gang Li Dao-You Guo Zhen-Ping Wu Wei-Hua Tang Laboratory of Information Functional Materials and Devices School of Science&State Key Laboratory of Information Photonics and Optical CommunicationsBeijing University of Posts and TelecommunicationsBeijing 100876China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China The Engineering Research Center for Semiconductor Integrated Technology Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China China Aerospace System Simulation Technology Co. Ltd.(Beijing)Beijing 100195China Division of Interdisciplinary and Comprehensive Research&Platform for Characterization and Test Suzhou Institute of Nano-Tech and Nano-BionicsChinese Academy of SciencesSuzhou 215123China Center for Optoelectronics Materials and Devices&Key Laboratory of Optical Field Manipulation of Zhejiang Province Department of PhysicsZhejiang Sci-Tech UniversityHangzhou 310018China School of Nano-Tech and Nano-Bionics University of Science and Technology of ChinaHefei 230026China College of Electronic and Optical Engineering&College of Microelectronics Nanjing University of Posts and TelecommunicationsNanjing 210046China National and Local Joint Engineering Laboratory for RF Integration and Micro-Packing Technologies Nanjing University of Posts and TelecommunicationsNanjing 210046China

We report the edge-defined-film-fed(EFG)-grown β-Ga_(2)O_(3)-based Schottky *** device has a reverse leakage current of ~nA and a rectified ratio of ~10^(4) at ±5 *** addition,the photodiode detector shows a dark current of 0.3 pA,a photo-responsivity(R) of 2.875 mA/W,a special detectivity(D*) of 10^(10) Jones,and an external quantum efficiency(EQE) of 1.4% at zero bias,illustrating a self-powered *** work may advance the development of the Ga_(2)O_(3)-based Schottky diode solar-blind photodetectors.

关键词： β-Ga_(2)O_(3)substrate Schottky photodiode solar-blind detection

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Circulation Variation Over the Western North Pacific and Its Association with Tropical Ssta Over the Indian Ocean and the Pacific

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Chinese Journal of Geophysics 2013年第4期56卷 382-399页

作者： YAN Hong‐Ming LI Qin‐Quan YUAN Yuan LI Chong‐Yin Yunnan Climate Center Kunming China National Climate Center Beijing China National Climate Center Beijing China State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China Institute of Meteorology PLA University of Science and Technology Nanjing China

The circulation variation over the western North Pacific and its relationship between circulation and tropical SSTA were investigated in this paper. The results show that western North Pacific (WNP) anticyclone/cyclone are two significantly anomalous phenomena at mid-low troposphere over WNP, and their variation is related to PJ wave line and zonal wave line at mid-high latitudes of Eurasia. Owing to this interrelation, WNP anticyclone/cyclone can influence the climate over East Asia and Eurasia. The results also show that the relationship between WNP anticyclone/cyclone in summer and SSTA is obviously asymmetric. Generally, evident WNP anticyclone occurs in summer of feeble El Niño years, related with warm SSTA in winter of mature El Niño years over the equatorial east Pacific and warm SSTA in spring and summer of weakening El Niño years over the Indian Ocean, which further displays that the WNP anticyclone plays an important bridge role in El Niño event influence on summer climate over East Asia. But the relationship between the obvious WNP cyclone and SSTA in the Indian Ocean is not steady. The formation and maintain of WNP anticyclone are mainly related to anomalous westerlies resulting from thermal contrast between SSTA over the Indian Ocean and SSTA over the Pacific. The possible cause of asymmetry is further investigated. The results show that the thermal contrasts between Indo-Pacific in El Niño and La Niña summer are accordant, which possibly results in asymmetric relationship between WNP anticyclone/cyclone and SSTA.

关键词： Western North Pacific (WNP) anticyclone/cyclone Indian Ocean basin model (IOBM) El Niño/La Niña event Walker circulation Indo‐Pacific thermal contrast

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A local character based method for solving linear systems of radiation diffusion problemsI

arXiv

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arXiv 2020年

作者： Ye, Shuai An, Hengbin Xu, Xinhai State Key Laboratory of High Performance Computing National University of Defense Technology Changsha410073 China Laboratory of Computational Physics Institute of Applied Physics and Computational Mathematics Beijing100094 China CAEP Software Center for High Performance Numerical Simulation Beijing100088 China Artificial Intelligence Research Center National Innovation Institute of Defense Technology Beijing100071 China

The radiation diffusion problem is a kind of time-dependent nonlinear equations. For solving the radiation diffusion equations, many linear systems are obtained in the nonlinear iterations at each time step. The cost of linear equations dominates the numerical simulation of radiation diffusion applications, such as inertial confinement fusion, etc. Usually, iterative methods are used to solve the linear systems in a real application. Moreover, the solution of the previous nonlinear iteration or the solution of the previous time step is typically used as the initial guess for solving the current linear equations. Because of the strong local character in ICF, with the advancing of nonlinear iteration and time step, the solution of the linear system changes dramatically in some local domain, and changes mildly or even has no change in the rest domain. In this paper, a local character-based method is proposed to solve the linear systems of radiation diffusion problems. The proposed method consists of three steps: Firstly, a local domain (algebraic domain) is constructed;secondly, the subsystem on the local domain is solved;and lastly, the whole system will be solved. Two methods are given to construct the local domain. One is based on the spatial gradient, and the other is based on the residual. numerical tests for a two-dimensional heat conduction model problem, and two real application models, the multi-group radiation diffusion equations and the three temperature energy equations, are conducted. The test results show that the solution time for solving the linear system can be reduced dramatically by using the local character-based method. Copyright © 2020, The Authors. All rights reserved.

关键词： Linear systems

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Accelerating relaxation through Liouvillian exceptional point

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Physical Review Research 2023年第4期5卷 043036-043036页

作者： Yan-Li Zhou Xiao-Die Yu Chun-Wang Wu Xie-Qian Li Jie Zhang Weibin Li Ping-Xing Chen Institute for Quantum Science and Technology College of Science National University of Defense Technology Changsha 410073 China Hunan Key Laboratory of Mechanism and technology of Quantum Information Changsha 410073 China Hefei National Laboratory Hefei 230088 Anhui China College of Science National University of Defense Technology Changsha 410073 China School of Physics and Astronomy and Centre for the Mathematics and Theoretical Physics of Quantum Non-equilibrium Systems University of Nottingham Nottingham NG7 2RD United Kingdom

We investigate speeding up of relaxation of Markovian open quantum systems with the Liouvillian exceptional point (LEP), where the slowest decay mode degenerates with a faster decay mode. The degeneracy significantly increases the gap of the Liouvillian operator, which determines the time scale of such systems in converging to stationarity and thus accelerates the relaxation process. We explore an experimentally relevant three-level atomic system whose eigenmatrices and eigenspectra are obtained completely analytically. This allows us to gain insights into the LEP and examine the respective dynamics with details. We illustrate that the gap can be further widened by Floquet engineering, which further accelerates the relaxation process. Finally, we extend this approach to analyze laser cooling of trapped ions, where vibrations (phonons) couple to the electronic states. An optimal cooling condition is obtained analytically, which agrees with both existing experiments and numerical simulations. In this paper, we provide analytical insights into understanding LEP as well as controlling and optimizing the dissipative dynamics of atoms and trapped ions.

关键词： Open quantum systems & decoherence Quantum control

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INTERDECADAL VARIATION OF THE RELATIONSHIP BETWEEN ENSO AND SUMMER INTERANNUAL CLIMATE VARIABILITY IN CHINA

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Journal of Tropical Meteorology 2007年第2期13卷 132-136页

作者：朱益民杨修群陈晓颖赵珊珊孙旭光 State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences Institute of Severe Weather and Climate Nanjing University Institute of meteorology PLA University of Science and Technology National Climate Center China Meteorological Administration

Interdecadal variation of the relationships between ENSO and the summer interannual climate variability in China is investigated by using techniques of sliding correlation analysis with the tropical Pacific SSTA and the observed surface air temperature and precipitation from stations in China. The results indicate that there are stable and robust relations that the Northern China is relatively dry during the developing phase of ENSO while the Yangtze River valley is relatively wet during the decaying phase of ENSO. On the other hand, interdecadal variations of the relations are also found in other regions. Over the time both prior to the Pacific decadal climate shift (before the late 1970s) and after it (after the late 1970s), during the developing phases of ENSO the summer precipitation anomaly in South China changed from below to above normal, whereas that in Northeast China changed from above to below normal; the summer surface air temperature anomaly in North and Northeast China changed from cooling to warming, whereas that in South China changed to cooling; during the decaying phases of ENSO the North China changed from wetter to dryer while the Huai River valley changed from dryer to normal; North China, Yangtze River valley and South China tend to be warmer. Based on the composite analysis of the NCAR/NCEP reanalyze datasets, significant differences existing in ENSO-related atmospheric circulation anomaly in East Asia during pre- and post-shift periods may be responsible for the interdecadal variation of relationships between ENSO and surface air temperature and precipitation in China.

关键词： ENSO PDO summer precipitation and temperature interannual variability interdecadal variation

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Cooling a mechanical resonator to the quantum regime by heating it

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Physical Review A 2016年第5期94卷 053836-053836页

作者： Yue Ma Zhang-qi Yin Pu Huang W. L. Yang Jiangfeng Du Center for Quantum Information Institute for Interdisciplinary Information Sciences Tsinghua University Beijing 100084 China Department of Physics Tsinghua University Beijing 100084 China Hefei National Laboratory for Physics Sciences at Microscale and Department of Modern Physics University of Science and Technology of China Hefei 230026 China State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics Wuhan Institute of Physics and Mathematics Chinese Academy of Sciences Wuhan 430071 China

We consider a mechanical resonator made of diamond, which contains a nitrogen-vacancy center (NV center) locating at the end of the oscillator. A second-order magnetic gradient is applied and induces coupling between mechanical modes and the NV center. By applying a proper external magnetic field, the energy difference between NV center electron spin levels can be tuned to match the energy difference between two mechanical modes a and b. A laser is used for continuously initializing the NV center electron spin. The mode a with lower frequency is driven by a thermal bath. We find that the temperature of the mode b is significantly cooled when the heating bath temperature is increased. We discuss the conditions that quantum regime cooling requires and confirm the results by numerical simulation. Finally we give the intuitive physical explanation of this unusual effect.

关键词： Cavity quantum electrodynamics Cooling & trapping Hybrid quantum systems Optomechanics Micromechanical & nanomechanical oscillators Nitrogen vacancy centers in diamond

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The Predictability of Ocean Environments that Contributed to the 2020/21 Extreme Cold Events in China:2020/21 La Niña and 2020 Arctic Sea Ice Loss

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Advances in Atmospheric sciences 2022年第4期39卷 658-675页

作者： Fei ZHENG Ji-Ping LIU Xiang-Hui FANG Mi-Rong SONG Chao-Yuan YANG Yuan YUAN Ke-Xin LI Ji WANG Jiang ZHU International Center for Climate and Environment Science(ICCES) Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science&TechnologyNanjing 210044China Department of Atmospheric and Environmental Sciences University at Albany State University of New YorkAlbanyNY 12222USA Department of Atmospheric and Oceanic Sciences&Institute of Atmospheric Sciences Fudan UniversityShanghai 200438China State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics(LASG) Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China School of Atmospheric Sciences Sun Yat-sen UniversityZhuhai 519082China National Climate Center Beijing 100081China University of Chinese Academy of Sciences Beijing 100049China Beijing Municipal Climate Center Beijing 100089China

Several consecutive extreme cold events impacted China during the first half of winter 2020/21,breaking the low-temperature records in many *** to make accurate climate predictions of extreme cold events is still an urgent *** synergistic effect of the warm Arctic and cold tropical Pacific has been demonstrated to intensify the intrusions of cold air from polar regions into middle-high latitudes,further influencing the cold conditions in ***,climate models failed to predict these two ocean environments at expected lead *** seasonal climate forecasts only predicted the 2020/21 La Niña after the signal had already become apparent and significantly underestimated the observed Arctic sea ice loss in autumn 2020 with a 1-2 month *** this work,the corresponding physical factors that may help improve the accuracy of seasonal climate predictions are further *** the 2020/21 La Niña prediction,through sensitivity experiments involving different atmospheric-oceanic initial conditions,the predominant southeasterly wind anomalies over the equatorial Pacific in spring of 2020 are diagnosed to play an irreplaceable role in triggering this cold event.A reasonable inclusion of atmospheric surface winds into the initialization will help the model predict La Niña development from the early spring of *** predicting the Arctic sea ice loss in autumn 2020,an anomalously cyclonic circulation from the central Arctic Ocean predicted by the model,which swept abnormally hot air over Siberia into the Arctic Ocean,is recognized as an important contributor to successfully predicting the minimum Arctic sea ice extent.

关键词： extreme cold event predictability La Niña Arctic sea ice loss

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A high-resolution land model with groundwater lateral flow,water use and soil freeze-thaw front dynamics and its applications in an endorheic basin

A high-resolution land model with groundwater lateral flow,w...

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第35届中国气象学会年会

作者： Zhenghui Xie Shuang Liu Yujin Zeng Junqiang Gao Peihua Qin Binghao Jia Jinbo Xie Bin Liu Ruichao Li Yan Wang Longhuan Wang State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences College of Earth Science University of Chinese Academy of Sciences Program in Atmospheric and Oceanic Sciences Princeton University School of Mathematics and Statistics Nanjing University of Information Science and Technology

Human water regulation(HWR), groundwater lateral flow(GLF) and the movement of frost and thaw fronts(FTFs) affect soil water and thermal processes, as well as energy and water exchanges between the land surface and atmosphere. Reasonable representation of these processes in land surface models is very important to improving the understanding of land-atmosphere interactions. In this study,mathematical descriptions of GLF, HWR and FTFs were synchronously incorporated into a high-resolution community land model named the Land Surface Model for Chinese Academy of sciences(CAS-LSM). With a series of atmospheric forcings and high-resolution land surface data from the Heihe Watershed Allied Telemetry Experimental Research(Hi WATER) program, numerical simulations of the period1981–2013 using CAS-LSM with 1-km resolution were conducted for an endorheic basin, the Heihe River Basin in China. Compared with observations, CAS-LSM reproduced the distributions of groundwater, evapotranspiration and permafrost reasonably, and well matched the temporal changes in ground temperature, heat fluxes and FTFs. Results illuminate the temporal and spatial characteristics of frozen soil and the changes in the land-atmosphere exchange of carbon, water and energy. The permafrost and seasonally frozen soil were distinguished. In the seasonally frozen areas, the maximum soil frost depth increased by 0.65 mm/year within natural areas and decreased by 2.12 mm/year in human-dominated areas. The active layer thickness increased 8.63 mm/year for permafrost. In the permafrost zone evapotranspiration and latent heat flux increased, and the sensible heat flux declined. In the human-dominated areas water use raised the latent heat flux and reduced the sensible heat flux, net ecosystem exchange and streamflow recharging to the eco-fragile region in the lower reaches. Results suggested that the land surface model CAS-LSM is a potential tool for studying land surface processes, especially in cold and arid r

关键词： A high-resolution land model with groundwater lateral flow,water use and soil freeze-thaw front dynamics and its applications in an endorheic basin CAS

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Constraining the spin-gravity coupling effects to the 10−10-level with dual-species atom interferometers

arXiv

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arXiv 2024年

作者： Gao, Dongfeng Zhou, Lin Wang, Jin Zhan, Mingsheng State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics Wuhan Institute of Physics and Mathematics Innovation Academy for Precision Measurement Science and Technology Chinese Academy of Sciences Wuhan430071 China Hefei National Laboratory Hefei230088 China Wuhan Institute of Quantum Technology Wuhan430206 China

Spin is one fundamental property of microscopic particles. A lot of theoretical work has postulated the possible coupling between spin and gravitation, which could result in the violation of equivalence principle. In our recent joint mass-and-energy test of the weak equivalence principle with a 10-meter 85Rb-87Rb dual-species atom interferometer, the Eötvös parameters of four 85Rb-87Rb combinations with specific atomic spin states were measured to the 10−10-level (L. Zhou et al., Phys. Rev. A 104, 022822). Here these experimental results are used to constrain the postulated spin-gravity coupling effects. The bounds on the spin-independent and spin-dependent anomalous passive gravitational mass tensors in Lämmerzahl’s model are set to the 10−10-level, which improves existing bounds by three orders of magnitude. The constraints to the spin-independent electron- and proton-gravity coupling parameters in the gravitational standard-model extension are set to the 10−6 GeV-level. Copyright © 2024, The Authors. All rights reserved.

关键词： Atoms

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