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Nonlinear dynamics in an artificial feedback spin maser

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arXiv 2024年

作者： Feng, Mingjun Wu, Lan Liu, Guobin National Time Service Center Chinese Academy of Sciences Xi’an710600 China University of Chinese Academy of Sciences Beijing100049 China Key Laboratory of Time Reference and Applications Chinese Academy of Sciences Xi’an710600 China

Spin masers with optical detection and artificial feedback are widely used in fundamental and practical applications. However, a full picture of the maser dynamics is still absent. By solving the feedback driven Bloch equations, we simulated the dynamics of an ideal spin maser in a broad parameter space. Rich nonlinear dynamics including high order harmonics generation, nonperiodic spin oscillations and frequency comb were revealed when the artificial feedback interaction exceeds the normal spin-field interaction. We also propose a pulse feedback spin maser protocol, which constructs an ultralow field magnetic frequency comb and could be useful in precision atomic magnetometers in searching for spin-dependent exotic interactions. Copyright © 2024, The Authors. All rights reserved.

关键词： Spin dynamics

Dynamic temperature compensation for wavelength-stable entangled biphoton generation

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arXiv 2024年

作者： Liu, Yuting Hong, Huibo Xiang, Xiao Quan, Runai Liu, Tao Cao, Mingtao Zhang, Shougang Dong, Ruifang Key Laboratory of Time Reference and Applications National Time Service Center Chinese Academy of Sciences Xi’an710600 China School of Astronomy and Space Science University of Chinese Academy of Sciences Beijing100049 China Hefei National Laboratory Hefei230088 China

A dynamic temperature compensation method is presented to stabilize the wavelength of the entangled biphoton source, which is generated via the spontaneous parametric down-conversion based on a MgO: PPLN waveguide. Utilizing the dispersive Fourier transformation technique combined with a digital proportional-integral-differential algorithm, the small amount of wavelength variation can be instantly identified and then compensated with active temperature correction. The long-term wavelength stability, assessed though Allan deviation, shows nearly a hundredfold enhancement, reaching 2.00 × 10−7 at the averaging time of 10000 s. It offers a simple, ready-to-use solution for precise wavelength control in quantum information processing. Copyright © 2024, The Authors. All rights reserved.

关键词： Magnesia

ALMA observations of massive clouds in the central molecular zone: slim filaments tracing parsec-scale shocks

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arXiv 2025年

作者： Yang, Kai Lu, Xing Zhang, Yichen Liu, Xunchuan Ginsburg, Adam Liu, Hauyu Baobab Cheng, Yu Feng, Siyi Liu, Tie Zhang, Qizhou Mills, Elisabeth A.C. Walker, Daniel L. Inutsuka, Shu-Ichiro Battersby, Cara Longmore, Steven N. Tang, Xindi Kauffmann, Jens Gu, Qilao Li, Shanghuo Luo, Qiuyi Kruijssen, J.M. Diederik Pillai, Thushara Qiao, Hai-Hua Qiu, Keping Shen, Zhiqiang Department of Astronomy School of Physics and Astronomy Shanghai Jiao Tong University 800 Dongchuan Rd. Minhang Shanghai200240 China School of Astronomy and Space Science Nanjing University 163 Xianlin Avenue Nanjing210023 China Ministry of Education Nanjing210023 China Shanghai Astronomical Observatory Chinese Academy of Sciences 80 Nandan Road Shanghai200030 China Department of Astronomy University of Florida P.O. Box 112055 GainesvilleFL32611 United States Department of Physics National Sun Yat-Sen University No. 70 Lien-Hai Road Kaohsiung City80424 Taiwan Center of Astronomy and Gravitation National Taiwan Normal University Taipei116 Taiwan National Astronomical Observatory of Japan 2-21-1 Osawa Mitaka Tokyo181-8588 Japan Department of Astronomy Xiamen University Zengcuo’an West Road Xiamen361005 China Center for Astrophysics Harvard & Smithsonian 60 Garden Street CambridgeMA02138 United States Department of Physics and Astronomy University of Kansas 1251 Wescoe Hall Drive LawrenceKS66045 United States UK ALMA Regional Centre Node Jodrell Bank Centre for Astrophysics The University of Manchester ManchesterM13 9PL United Kingdom Department of Physics Graduate School of Science Nagoya University Furo-cho Chikusa-ku Nagoya464-8602 Japan Department of Physics University of Connecticut 196A Auditorium Road StorrsCT06269 United States Astrophysics Research Institute Liverpool John Moores University IC2 Liverpool Science Park 146 Brownlow Hill LiverpoolL3 5RF United Kingdom Research DAO Munich Germany Xinjiang Astronomical Observatory 150 Science 1-Street Xinjiang Urumqi830011 China University of Chinese Academy of Sciences Beijing100080 China Key Laboratory of Radio Astronomy Chinese Academy of Sciences Urumqi830011 China Xinjiang Key Laboratory of Radio Astrophysics Urumqi830011 China Haystack Observatory Massachusetts Institute of Technology 99 Millstone Road WestfordMA01886 United States Chair of Remote Se

The central molecular zone (CMZ) of our Galaxy exhibits widespread emission from SiO and various complex organic molecules (COMs), yet the exact origin of such emission is uncertain. Here we report the discovery of a ... 详细信息

关键词： Molecules

Indoor UWB Localization Based on Improved Intelligent Optimization Algorithms

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Indoor UWB Localization Based on Improved Intelligent Optimi...

Internet of Things, Automation and Artificial Intelligence (IoTAAI), International Conference on

作者： Shuaichen Li Jianfeng Wu National Time Service Center Chinese Academy of Sciences Xian China Key Laboratory of Time Reference and Applications Chinese Academy of Sciences Xi’an China School of Integrated Circuits University of Chinese Academy of Sciences Beijing China College of Electronic Electrical and Communication Engineering University of Chinese Academy of Sciences Beijing China

ISBN: (数字)9798350386974

ISBN: (纸本)9798350386981

In response to the slow convergence of the original intelligent optimization algorithm and the possibility of converging to locally optimal solutions, this paper proposes the Logistic Mapping-Gaussian Mutation-Spiral Flight improvement strategy. The improvement in performance by the proposed strategy for the intelligent optimization algorithm is verified using the Grey Wolf Optimization Algorithm (GWO) and Egret Swarm Optimization Algorithm (ESOA). First, the improved GWO algorithm was tested with both unimodal and multimodal standard test functions, and the results were compared. The results show that the improved algorithm has a significant improvement in the accuracy and stability. Next, the improvement strategy was applied to the ESOA algorithm to solve for indoor positioning in UWB. The experimental results show that the improved algorithm significantly reduces both positioning error and standard deviation, which was reduced by 17.69% compared with the algorithm before the improvement, and the standard deviation is approximately 1/10 of the pre improvement level. Moreover, Improved algorithm requires a smaller minimum population and fewer iterations and has better convergence ability. These results indicate that the proposed improvement strategy can effectively enhance the performance of intelligent optimization algorithms and provide new ideas and methods for better solving optimization problems and indoor UWB positioning problems.

关键词： Location awareness Accuracy Spirals Heuristic algorithms Position measurement Approximation algorithms Optimization Standards Convergence Logistics

Versatile quantum microwave photonic signal processing platform based on coincidence window selection technique

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Advanced Photonics Nexus 2024年第5期3卷 130-139页

作者： Xinghua Li Yifan Guo Xiao Xiang Runai Quan Mingtao Cao Ruifang Dong Tao Liu Ming Li Shougang Zhang Chinese Academy of Sciences National Time Service CenterKey Laboratory of Time Reference and ApplicationsXi’anChina University of Chinese Academy of Sciences School of Astronomy and Space ScienceBeijingChina Hefei National Laboratory HefeiChina Chinese Academy of Sciences Institute of SemiconductorsState Key Laboratory on Integrated OptoelectronicsBeijingChina University of Chinese Academy of Sciences School of ElectronicElectrical and Communication EngineeringBeijingChina University of Chinese Academy of Sciences Center of Materials Science and Optoelectronics EngineeringBeijingChina

Quantum microwave photonics(QMWP)is an innovative approach that combines energy-time entangled biphoton sources as the optical carrier with time-correlated single-photon detection for highspeed radio frequency(RF)signal *** groundbreaking method offers unique advantages,such as nonlocal RF signal encoding and robust resistance to dispersion-induced frequency *** explore the versatility of processing the quantum microwave photonic signal by utilizing coincidence window selection on the biphoton coincidence *** demonstration includes finely tunable RF phase shifting,flexible multitap transversal filtering(with up to 14 taps),and photonically implemented RF mixing,leveraging the nonlocal RF mapping characteristic of *** accomplishments significantly enhance the capability of microwave photonic systems in processing ultraweak signals,opening up new possibilities for various applications.

关键词： microwave photonics quantum entanglement source window postselection

Precision determination of the oscillating-magnetic-field-induced second-order Zeeman shift of a single-Ca+40-ion optical clock

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Physical Review A 2024年第6期110卷 063102-063102页

作者： Zixiao Ma Baolin Zhang Yao Huang Ruming Hu Mengyan Zeng Kelin Gao Hua Guan State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics Innovation Academy of Precision Measurement Science and Technology Chinese Academy of Sciences Wuhan 430071 China University of Chinese Academy of Sciences Beijing 100049 China Key Laboratory of Time Reference and Applications Chinese Academy of Sciences Wuhan 430071 China Present address: School of Physics Peking University. Hefei National Laboratory University of Science and Technology of China Hefei 230088 China Wuhan Institute of Quantum Technology Wuhan 430206 China

A detailed investigation of the radio-frequency-induced oscillating magnetic field in a laboratory Ca+40-ion optical clock was conducted using the Autler-Townes (AT) splitting and Zeeman precession methods. It was determined that the corresponding relative second-order Zeeman shifts are below 1×10−20. By accounting for the quadratic Zeeman shift caused by the oscillating magnetic field, we accurately determined the Landé g-factor ratio of D5/2 and S1/2 states, gD/gS, to be 0.599 488 79(2). Moreover, we proposed a technique to determine the oscillating magnetic field by evaluating the variation of the measured Landé g-factor. This methodology can be easily utilized to determine the oscillating magnetic field in transportable trapped ion optical clocks.

关键词： Atomic & molecular processes in external fields Cooling & trapping Optical pumping Stark effect Zeeman effect

Observation of Continuous time Crystal in a Spin Maser System

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arXiv 2024年

作者： Wang, Weiyu Feng, Mingjun Ma, Qianjin Cai, Zi Li, Erwei Liu, Guobin National Time Service Center Chinese Academy of Sciences Xi’an710600 China Key Laboratory of Time Reference and Applications Chinese Academy of Sciences Xi’an710600 China University of Chinese Academy of Sciences Beijing100049 China Wilczek Quantum Center Key Laboratory of Artificial Structures and Quantum Control School of Physics and Astronomy Shanghai Jiao Tong University Shanghai200240 China Shanghai Research Center for Quantum Sciences Shanghai201315 China

Pair interaction potentials between atoms in a crystal are in general non-monotonic in distance, with a local minimum whose position gives the lattice constant of the crystal. A temporal analogue of this idea of crystal formation is still pending despite intensive studies on the time crystal phase. In a hybrid spin maser system with a time delay feedback, we report the observation of a continuous time crystal induced by a retarded interaction with a characteristic time scale. This nonequilibrium phase features a self-sustained oscillation with an emergent frequency other than the intrinsic Larmor precession frequency of the spin maser system. It is shown that the amplitude of the oscillation is robust against perturbation, while its time phase randomly distributes from 0 to 2π for different realizations, a signature of spontaneous continuous time translation symmetry breaking. This CTC phase emerges only when the feedback strength exceeds a critical value, at which the system experiences a first order phase transition. Such a retarded interaction induced CTC is closer to the original idea of crystal, compared to mechanisms in other time crystal proposals. Copyright © 2024, The Authors. All rights reserved.

关键词： Crystals

Maximization of rf-signal recovery in quantum microwave photonics systems

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Physical Review Applied 2024年第2期21卷 024020-024020页

作者： Yaqing Jin Xinghua Li Ye Yang Ruifang Dong Xiao Xiang Runai Quan Huibo Hong Tao Liu Mingtao Cao Baihong Li Xiaofei Zhang Ming Li Shougang Zhang Key Laboratory of Time Reference and Applications National Time Service Center Chinese Academy of Sciences Xi’an 710600 China School of Astronomy and Space Science University of Chinese Academy of Sciences Beijing 100049 China State Key Laboratory on Integrated Optoelectronics Institute of Semiconductors Chinese Academy of Sciences Beijing 100083 China The 29th Research Institute of China Electronics Technology Group Corporation Chengdu 610029 China Hefei National Laboratory Hefei 230088 China Department of Physics Shaanxi University of Science and Technology Xi’an 710021 China School of Electronic Electrical and Communication Engineering University of Chinese Academy of Sciences Beijing 100049 China

Quantum microwave photonics (QMWP) technology, which harnesses energy-time-entangled biphotons as optical carriers and employs time-correlated single-photon detection for high-speed rf-signal recovery, has demonstrated remarkable potential in achieving nonlocal rf-signal coding and efficient rf-signal recovery from significant dispersion interference. In this paper, we expound on the principle of maximizing the recovered rf signals in QMWP systems. Through theoretical analysis and experimental validation, we establish a precise relationship between the recovered rf signal’s magnitude, the input rf signal’s frequency, involved dispersions, and the width of the coincidence selection window. This enables us to determine the optimal width for the coincidence selection window and the corresponding magnitude of the maximized rf signal given the dispersion. These findings offer valuable guidance for improving QMWP systems, thus expanding their potential applications.

关键词： Optical quantum information processing Photon pairs & parametric down-conversion Photonics Quantum correlations in quantum information Quantum entanglement Quantum state transfer Radio frequency techniques Microwave techniques

A versatile quantum microwave photonic signal processing platform based on coincidence window selection technique

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arXiv 2024年

作者： Li, Xinghua Guo, Yifan Xiang, Xiao Quan, Runai Cao, Mingtao Dong, Ruifang Liu, Tao Li, Ming Zhang, Shougang Key Laboratory of Time Reference and Applications National Time Service Center Chinese Academy of Sciences Xi’an710600 China School of Astronomy and Space Science University of Chinese Academy of Sciences Beijing100049 China Hefei National Laboratory Hefei230088 China State Key Laboratory on Integrated Optoelectronics Institute of Semiconductors Chinese Academy of Sciences Beijing100083 China School of Electronic Electrical and Communication Engineering University of Chinese Academy of Sciences Beijing100049 China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of Sciences Beijing100190 China

Quantum microwave photonics (QMWP) is an innovative approach that combines energy-time entangled biphoton sources as the optical carrier with time-correlated single-photon detection for high-speed RF signal recovery. This groundbreaking method offers unique advantages such as nonlocal RF signal encoding and robust resistance to dispersion-induced frequency fading. This paper explores the versatility of processing the quantum microwave photonic signal by utilizing coincidence window selection on the biphoton coincidence distribution. The demonstration includes finely-tunable RF phase shifting, flexible multi-tap transversal filtering (with up to 15 taps), and photonically implemented RF mixing, leveraging the nonlocal RF mapping characteristic of QMWP. These accomplishments significantly enhance the capability of microwave photonic systems in processing ultra-weak signals, opening up new possibilities for various applications. © 2024, CC BY.

关键词： Microwave photonics