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Experimental research on Carrier Redistribution in InAs/GaAs quantum Dots

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Chinese Physics Letters 2012年第9期29卷 147-150页

作者： LI Chuan-Feng CHEN Geng GONG Ming LI Hai-Qiao NIU Zhi-Chuan Key laboratory of quantum Information University of Science and Technology of ChinaHefei 230026 State Key laboratory for Superlattices and Microstructures Institute of SemiconductorsChinese Academy of SciencesBeijing 100083

In order to investigate the carrier redistribution mechanisms in InAs/GaAs self-assembled quantum dots,the photoluminescent energy peak shift is studied with increasing excitation *** for samples of relatively low density,it is shown that the energy peak position could recover slowly after a fast redshift,associated with the increasing excitation power.A theoretical model is presented,which involves the Auger effect assisting carrier recapture as important mechanisms during the relaxation process.

关键词： process. excitation slowly

The detection, extraction and parameter estimation of extreme-mass-ratio inspirals with deep learning

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Science China(Physics,Mechanics & Astronomy) 2025年第1期Mechanics & Astronomy) .卷 86-96页

作者： Qianyun Yun Wen-Biao Han Yi-Yang Guo He Wang Minghui Du Hangzhou Institute for Advanced Study University of Chinese Academy of Sciences Shanghai Astronomical Observatory Chinese Academy of Sciences School of Physics and Astronomy Shanghai Jiao Tong University School of Astronomy and Space Science University of Chinese Academy of Sciences Taiji laboratory for Gravitational Wave Universe (Beijing/Hangzhou) University of Chinese Academy of Sciences Lanzhou Center for Theoretical Physics Key Laboratory of Theoretical Physics of Gansu Province Key Laboratory of Quantum Theory and Applications of MoE Lanzhou University Institute of Theoretical Physics & research Center of Gravitation Lanzhou University International Centre for Theoretical Physics Asia-Pacific (ICTP-AP) University of Chinese Academy of Sciences (UCAS) Center for Gravitational Wave Experiment National Microgravity Laboratory Institute of Mechanics Chinese Academy of Sciences

One of the primary goals of space-borne gravitational wave detectors is to detect and analyze extreme-mass-ratio inspirals(EMRIs). This task is particularly challenging because EMRI signals are complex, lengthy, and faint. In this work, we introduce a2-layer convolutional neural network(CNN) approach to detect EMRI signals for space-borne detectors, achieving a true positive rate(TPR) of 96.9% at a 1% false positive rate(FPR) for signal-to-noise ratio(SNR) from 50 to 100. Especially, the key intrinsic parameters of EMRIs such as the mass, spin of the supermassive black hole(SMBH) and the initial eccentricity of the orbit can also be inferred directly by employing a neural network. The mass and spin of the SMBH can be determined at 99% and 92% respectively. This will greatly reduce the parameter spaces and computing cost for the following Bayesian parameter *** model also has a low dependency on the accuracy of the waveform model. This study underscores the potential of deep learning methods in EMRI data analysis, enabling the rapid detection of EMRI signals and efficient parameter estimation.

关键词： gravitational wave EMRIs deep-learing

Amino acid assisted aqueous synthesis of highly stable CsPbBr_(3)nanocrystals for cell imaging

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Nano research 2025年第1期18卷 675-683页

作者： Xue Li Yanan Guo Guoying Tan Qingyi Liu Nan Song Yu Tang State Key laboratory of Applied Organic Chemistry Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu ProvinceCollege of Chemistry and Chemical EngineeringLanzhou UniversityLanzhou 730000China State Key laboratory of Baiyunobo Rare Earth Resource researches and Comprehensive Utilization Baotou Research Institute of Rare EarthsBaotou 014030China

Lead halide perovskite nanocrystals(NCs)exhibit excellent optoelectronic performance and have drawn great interests in the fields of biological imaging and ***,the poor stability of CsPbX_(3)(X=Cl,Br,I)in water is still a challenge to hinder their practical *** this work,a facile strategy has been developed for aqueous synthesis of CsPbX_(3) nanocrystals,in which L-glutamic acid(LGlu)has been used to replace oleic acid in the synthetic *** from the synergic effects of L-Glu and oleylamine(OAm),CsPbBr_(3)nanocrystals(L-Glu/OAm-CsPbBr_(3)NCs)with high water stability have been directly prepared under a mild condition at room temperature in water,facilitated by the process of crystal phase transformation from Cs_(4)PbBr_(6) to CsPbBr_(3).L-Glu/OAm-CsPbBr_(3)NCs exhibit a high quantum yield of 85%and a narrow full width at half maximum of 16 nm,demonstrating their efficient luminescence in ***,L-Glu on the surface have contributed greatly to an acidic environment and passivation of surface defects,improving the water stability and dispersibility of CsPbBr_(3)***,L-Glu/OAm-CsPbBr_(3)NCs exhibit great biocompatibility due to the presence of L-Glu,resulting in their good performance for HeLa cell ***,we propose a facile and effective method to prepare CsPbBr_(3)nanocrystals with excellent water stability by using L-Glu and OAm as cooperated ligands and expand their application in cell imaging.

关键词： aqueous synthesis cell imaging lead halide perovskite nanocrystals L-glutamic acid phase transformation

Theory of the magnon Kerr effect in cavity magnonics

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Science China(Physics,Mechanics & Astronomy) 2019年第8期62卷 93-103页

作者： GuoQiang Zhang YiPu Wang JianQiang You quantum Physics and quantum Information Division Beijing Computational Science Research Center Interdisciplinary Center of quantum Information and Zhejiang Province Key laboratory of quantum Technology and Device Department of Physics and State Key Laboratory of Modern Optical Instrumentation Zhejiang University

We develop a theory for the magnon Kerr effect in a cavity magnonics system, consisting of magnons in a small yttrium iron garnet(YIG) sphere strongly coupled to cavity photons, and use it to study the bistability in this hybrid system. To have a complete picture of the bistability phenomenon, we analyze two different cases in driving the cavity magnonics system, i.e.,directly pumping the YIG sphere and the cavity, respectively. In both cases, the magnon frequency shifts due to the Kerr effect exhibit a similar bistable behavior but the corresponding critical powers are different. Moreover, we show how the bistability of the system can be demonstrated using the transmission spectrum of the cavity. Our results are valid in a wide parameter regime and generalize the theory of bistability in a cavity magnonics system.

关键词： magnon Kerr effect cavity magnonics bistability hybrid system

Nonadiabatic holonomic quantum computation and its optimal control

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Science China(Information Sciences) 2023年第8期66卷 23-44页

作者： Yan LIANG Pu SHEN Tao CHEN Zheng-Yuan XUE Key laboratory of Atomic and Subatomic Structure and quantum Control (Ministry of Education) School of Physics South China Normal University Guangdong Provincial Key laboratory of quantum Engineering and quantum Materials Guangdong-Hong Kong Joint Laboratory of Quantum Matter Frontier Research Institute for PhysicsSouth China Normal University Hefei National laboratory

The geometric phase has the intrinsic property of being resistant to some types of local noises as it only depends on global properties of the evolution path. Meanwhile, the non-Abelian geometric phase is in the matrix form, and thus can naturally be used to implement high performance quantum gates,i.e., the so-called holonomic quantum computation. This article reviews recent advances in nonadiabatic holonomic quantum computation, and focuses on various optimal control approaches that can improve the gate performance, in terms of gate fidelity and robustness. Besides, we also pay special attention to its possible physical realizations and some concrete examples of experimental realizations. Finally, with all these efforts, within state-of-the-art technology, the performance of the implemented holonomic quantum gates can outperform the conventional dynamical ones, under certain conditions.

关键词： quantum computation geometric phases quantum gates optimal control

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quantum machine learning

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National Science Review 2019年第1期6卷 26-28页

作者： Jonathan Allcock Shengyu Zhang Tencent quantum laboratory

INTRODUCTION quantum machine learning is at the crossroads of two of the most exciting current areas of research:quantum computing and classical machine learning. Although the field is still in its infancy,the body of literature is already large enough to warrant several review articles [1–3]. This short survey focuses on a selection of significant recent results on the subtopic of quantum neural net-

关键词： RBM quantum machine learning

The laser-intensity dependence of the photoassociation spectrum of the ultracold Cs_2(6S_(1/2) + 6P_(1/2))0_u^+ long-range molecular state

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Chinese Physics B 2013年第8期22卷 732-737页

作者：金丽冯国胜武寄洲马杰汪丽蓉肖连团贾锁堂 State Key laboratory of quantum Optics and quantum Optics Devices Laser Spectroscopy Laboratory Shanxi University

The high-resolution photoassociation spectrum of the ultracold cesium molecular 0＋ state below the 6S1/2 ＋ 6PI/2 limit is presented in this paper. The saturation of the photoassociation scattering probability is observed from the depen dence of the trap-loss probability on the photoassociation laser intensity. The corresponding resonant line width is also demonstrated to increase linearly with increasing photoassociation laser intensity. Our experimental data have good con sistency with the theoretical saturation model of Bohn and Julienne [Bohn J L and Julienne P S 1999 Phys. Rev. A 60 1].

关键词： photoassociation spectrum intensity dependence high resolution

Photon counts modulation in optical time domain reflectometry

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Chinese Physics B 2011年第6期20卷 258-262页

作者：王晓波王晶晶张国锋肖连团贾锁堂 State Key laboratory of quantum Optics and quantum Optics Devices Laser Spectroscopy Laboratory Shanxi University

The quantum fluctuation of photon counting limits the field application of optical time domain reflection. A method of photon counts modulation optics time domain reflection with single photon detection at 1.55 μm is presented. The influence of quantum fluctuation can be effectively controlled by demodulation technology since quantum fluctuation shows a uniform distribution in the frequency domain. Combined with the changing of the integration time of the lock-in amplifier, the signal to noise ratio is significantly enhanced. Accordingly the signal to noise improvement ratio reaches 31.7 dB compared with the direct photon counting measurement.

关键词： single photon detection optical time domain reflection modulation quantum fluctuation

Single-photon modulation spectrum

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Chinese Physics B 2014年第1期23卷 30-34页

作者：刘岩于波何博张国峰肖连团贾锁堂 State Key laboratory of quantum Optics and quantum Optics Devices Laser Spectroscopy Laboratory Shanxi University

We present a robust method of single-photon modulation by directly modulating the single photons and observe its fre- quency spectrum. Compared with conventional photon counting technique, the single-photon modulation spectrum shows that the method could not only realize high-frequency modulation but also obtain higher signal-to-noise ratio. Moreover, the theoretical calculations show good agreement with the experimental results.

关键词： signal-to-noise ratio single-photon modulation spectrum