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Emergence of steady currents due to strong prethermalization

Physical Review A 2023年第2期107卷 022220-022220页

作者： Xiansong Xu Chu Guo Dario Poletti Science Mathematics and Technology Cluster Singapore University of Technology and Design 8 Somapah Road Singapore 487372 Singapore College of Physics and Electronic Engineering and Center for Computational Sciences Sichuan Normal University Chengdu 610068 China Henan Key Laboratory of Quantum Information and Cryptography Zhengzhou Henan 450000 China Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education Department of Physics and Synergetic Innovation Center for Quantum Effects and Applications Hunan Normal University Changsha 410081 China EPD Pillar Singapore University of Technology and Design 8 Somapah Road Singapore 487372 Singapore The Abdus Salam International Centre for Theoretical Physics Strada Costiera 11 34151 Trieste Italy Centre for Quantum Technologies National University of Singapore Singapore 117543 Singapore

A steady current between baths is a manifestation of the prethermalization phenomenon, a quasiequilibrium dynamic process with weak breaking of conserved quantities. We consider two finite nonintegrable many-body baths, each following the eigenstate thermalization hypothesis and each prepared in a random product state with fixed and different energy constraints, i.e., within the mean energy ensemble. Such an initialization, not being constrained to superpositions or mixtures of many-body eigenstates, opens the door to experimental realization and also significantly simplifies numerical simulations. We show that such a dynamic process is typical as the current variance decreases exponentially with respect to the size of baths. We also demonstrate that the emerging current is prethermalized in a strong sense, analogous to strong thermalization, meaning that the current values stay close to the microcanonical one most of the time.

关键词： Eigenstate thermalization Nonequilibrium statistical mechanics Open quantum systems & decoherence Nonequilibrium systems

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Deep representation method for radar emitter signal using wavelet packets decomposition

Deep representation method for radar emitter signal using wa...

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IET International Radar Conference 2018, IRC 2018

作者： Cao, Yang Bai, Jin Liang Li, Hongbo Zhao, Jian Liu, Shuo Gao, Zhiyong National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing China School of Electronics and Information Engineering Harbin Institute of Technology Harbin China

Signal representation is to transform the intercepted original signal into feature parameters, which is the basis for the electronic reconnaissance system to analyse and identify a radar. The traditional method is to manually design a limited number of features with prior knowledge, which can only achieve the desired results in specific applications. Therefore, it is necessary to study signal representation methods that are more adaptable, reasonable, and effective. This study proposes a feature-level design scheme that extracts multi-level signal feature parameters to obtain deep essential feature representations, which is consistent with deep-learning frameworks. Through the decomposition through wavelet packet transform (WPT), the best sub-band tree structure of the signal can be obtained, and the depth representation of the signal can be well achieved, which can meet requirements of time-frequency analysis automatically. Here, Symlets wavelet packet decomposition (WPD) is used as an example to implement multi-layer signal feature representation. The combination of characteristic parameters at different levels can reflect the different information contained in different radar signals. The simulation results show that the method can effectively identify the modulation mode of radar signals and enhance the information mining ability from radar signals. © 2019 Institution of Engineering and technology. All rights reserved.

关键词： Radar

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Pressure level of maximum radiative heating enhancement in response to increasing CO_(2) over the global monsoon area

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Atmospheric and Oceanic science Letters 2021年第3期14卷 19-24页

作者： Xia Qu Gang Huang Xiaocong Wang Center for Monsoon System Research Institute of Atmospheric PhysicsChinese Academy of SciencesBeijingChina State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of SciencesBeijingChina Laboratory for Regional Oceanography and Numerical Modeling Qingdao National Laboratory for Marine Science and TechnologyQingdaoChina University of Chinese Academy of Sciences BeijingChina

Based on the 1%CO_(2) experiment of CMIP6,in response to increasing CO_(2),the summer-mean radiative heating(RH)over the global monsoon area(MA)generally features an increasing response in the mid-troposphere and a decreasing response in the lower and upper *** pressure level of the maximum RH increase over the Asian MA is the highest and largest in range(500–775 hPa);the maximum increases over the North African,South American,and Australian MA are at 550–600 hPa;throughout the North American MA,the maximum heating increase is at 600 hPa;and the levels of the maximum over South Africa are 600 and 775 *** most of the global MA,the maximum enhancement of RH is at 500,550,and 600 *** is mainly led by the increase in cloud water at and above the maximum level and the decrease in cloud water below,which leads to similar changes in total cloud *** of the longwave heating(cooling)effect at the cloud base(top),the RH enhancements peak at those *** the northeast part of the Asian MA and southeast part of the South African MA,RH enhancement peaks at 700 and 775 hPa,mainly attributable to the cloud water reduction *** reduction leads to similar changes in total *** to the longwave cooling effect at the cloud top,the reduction contributes to the RH enhancement at the corresponding maximum levels.

关键词： Radiative heating Increasing CO_(2) Global monsoon area Cloud

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Complex-valued K-means clustering of interpolative separable density fitting algorithm for large-scale hybrid functional enabled ab initio molecular dynamics simulations within plane waves

arXiv

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arXiv 2022年

作者： Jiao, Shizhe Li, Jielan Qin, Xinming Wan, Lingyun Hu, Wei Yang, Jinlong Hefei National Research Center for Physical Sciences at the Microscale Anhui Center for Applied Mathematics University of Science and Technology of China Anhui Hefei230026 China Key Laboratory of Precision and Intelligent Chemistry Department of Chemical Physics University of Science and Technology of China Anhui Hefei230026 China

K-means clustering, as a classic unsupervised machine learning algorithm, is the key step to select the interpolation sampling points in interpolative separable density fitting (ISDF) decomposition. Real-valued K-means clustering for accelerating the ISDF decomposition has been demonstrated for large-scale hybrid functional enabled ab initio molecular dynamics (hybrid AIMD) simulations within plane-wave basis sets where the Kohn-Sham orbitals are real-valued. However, it is unclear whether such K-means clustering works for complex-valued Kohn-Sham orbitals. Here, we apply the K-means clustering into hybrid AIMD simulations for complex-valued Kohn-Sham orbitals and use an improved weight function defined as the sum of the square modulus of complex-valued Kohn-Sham orbitals in K-means clustering. numerical results demonstrate that this improved weight function in K-means clustering algorithm yields smoother and more delocalized interpolation sampling points, resulting in smoother energy potential, smaller energy drift and longer time steps for hybrid AIMD simulations compared to the previous weight function used in the real-valued K-means algorithm. In particular, we find that this improved algorithm can obtain more accurate oxygen-oxygen radial distribution functions in liquid water molecules and more accurate power spectrum in crystal silicon dioxide compared to the previous K-means algorithm. Finally, we describe a massively parallel implementation of this ISDF decomposition to accelerate large-scale complex-valued hybrid AIMD simulations containing thousands of atoms (2,744 atoms), which can scale up to 5,504 CPU cores on modern supercomputers. © 2022, CC BY.

关键词： Molecular dynamics

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Station Layout Optimization Genetic Algorithm for Four Stations TDOA Location

Station Layout Optimization Genetic Algorithm for Four Stati...

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第二届人工智能、网络与信息技术国际研讨会

作者： Ruiqi Sun Zhonghang He Lu Gao Jinliang Bai National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics

Station layout has a direct impact on localization precision for four-station TDOA(time difference of arrival) location system. In order to optimize the overall location precision of targets in certain area, genetic algorithm for station layout optimization is presented. GDOP is regarded as the measurement rule of location precision. Then the multi-object programming mathematical model of station layout optimization is built. The optimal solution is searched by genetic algorithm. Consequently, the optimal layout of station is obtained. The simulation provides the GDOP distribution of two station layouts. One is the initial station layout, and the other is the optimal station layout. The simulation results show that for the optimal station layout, the effect of improving the location precision is obvious, and also indicate the validity of genetic algorithm.

关键词： Station Layout Optimization Genetic Algorithm for Four Stations TDOA Location

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Topology Optimization of Complex Network based on NSGA-II 4

Topology Optimization of Complex Network based on NSGA-II

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4th IEEE Advanced Information technology, Electronic and Automation Control Conference, IAEAC 2019

作者： Bin, Zhang Gan, Zhi-Chun Wen, Chen Hu, Qiang-Qiang Hou, Jian-Feng National University of Defense Technology Departments of Information and Communication China Science and Technology on Test Physics Numerical Mathematic Laboratory China

ISBN: (纸本)9781728119076

This paper proposes a complex network topology optimization method based on NSGA-II with degrees and edges number unchanged. The method selects the elite parent networks by applying non-dominated layer sorting and congestion degree calculation through the network crossover and mutation operation to achieve maximum network efficiency and network invulnerability. Simulation analysis shows that the method can significantly improve the invulnerability and network efficiency of the initial networks at the same time. Optimizing the network efficiency makes the network connection show a negative correlation. The network presents a "multi-core decentralized" structure;optimizing the network invulnerability makes the connection show a positive correlation, the network presents a "close core and scattered periphery" structure;the cooperative optimization makes the network present a "tighter core and large periphery" structure, which is proved with good theoretical generality and practical application value. © 2019 IEEE.

关键词： Complex networks

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Data block processing structure for airship-borne passive bistatic radar

Data block processing structure for airship-borne passive bi...

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IET International Radar Conference 2018, IRC 2018

作者： Xu, Feng Liu, Xin Liu, Li Wang, Chao Wang, YiFei National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing100076 China DFH Satellite Co. Ltd Beijing100094 China

Serious ground clutter is of significant influence for target detection in an airship-borne passive bistatic radar (ABPBR) using frequency modulated broadcasting signals. The authors propose a data segment processing scheme to recover the direct signal from multi-path clutter and suppress the multi-path in the surveillance channel in an ABPBR. Super exponential (SE) equaliser and sample matrix inversion algorithm are exploited to recover the transmitted signal and suppress the serious multi-path interference, respectively. It is shown that the proposed algorithms can accomplish the target detection task effectively by computer simulations. © 2019 Institution of Engineering and technology. All rights reserved.

关键词： Airships

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DRUM: Diffusion-based runoff model for probabilistic flood forecasting

arXiv

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arXiv 2024年

作者： Ou, Zhigang Nai, Congyi Pan, Baoxiang Pan, Ming Shen, Chaopeng Jiang, Peishi Liu, Xingcai Tang, Qiuhong Li, Wenqing Zheng, Yi School of Environmental Science and Engineering Southern University of Science and Technology Shenzhen China Key Laboratory of Earth System Numerical Modeling and Application Institute of Atmospheric Physics Chinese Academy of Science Beijing China Scripps Institution of Oceanography University of California La Jolla San DiegoCA United States Civil and Environmental Engineering The Pennsylvania State University University ParkPA United States Atmospheric Climate and Earth Sciences Division Pacific Northwest National Laboratory RichlandWA United States Key Laboratory of Water Cycle and Related Land Surface Processes Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing China State Key Laboratory of Stimulation and Regulation of Water Cycles in River Basins China Institute of Water Resources and Hydropower Research Beijing China

Reliable flood forecasting remains a critical challenge due to persistent underestimation of peak flows and inadequate uncertainty quantification in current approaches. We present DRUM (Diffusion-based Runoff Model), a generative AI solution for probabilistic runoff prediction. DRUM builds up an iterative refinement process that generates ensemble runoff estimates from noise, guided by past meteorological conditions, present meteorological forecasts, and static catchment attributes. This framework allows learning complex hydrological behaviors without imposing explicit distributional assumptions, particularly benefiting extreme event prediction and uncertainty quantification. Using data from 531 representative basins across the contiguous United States, DRUM outperforms state-of-the-art deep learning methods in runoff forecasting regarding both deterministic and probabilistic skills, with particular advantages in extreme flow (1%) predictions. DRUM demonstrates superior flood early warning skill across all magnitudes and lead times (1–7 days), achieving F1 scores near 0.4 for extreme events under perfect forecasts and maintaining robust performance with operational forecasts, especially for longer lead times and high-magnitude floods. When applied to climate projections through the 21st century, DRUM reveals increasing flood vulnerability in 47.8–57.1% of basins across emission scenarios, with particularly elevated risks along the West Coast and Southeast regions. These advances demonstrate significant potential for improving both operational flood forecasting and long-term risk assessment in a changing climate. © 2024, CC BY-NC-SA.

关键词： Floods

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Micro-mechanism of low-density lipoproteins (LDL) transport in multi-layered arterial wall 5

Micro-mechanism of low-density lipoproteins (LDL) transport ...

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2020 5th International Seminar on Computer technology, Mechanical and Electrical Engineering, ISCME 2020

作者： Wang, Erhui Zhang, Xuelan Suleiman, Kheder Shu, Chang Zheng, Liancun School of Energy and Environmental Engineering University of Science and Technology Beijing Beijing100083 China State Key Laboratory of Cardiovascular Disease Center of Vascular Surgery Fuwai Hospital National Center for Cardiovascular Diseases Chinese Academy of Medical Sciences and Peking Union Medical College Beijing100037 China School of Mathematics and Physics University of Science and Technology Beijing Beijing100083 China

This paper investigates micro-mechanism of LDL transport numerically in a multi-layer arterial wall. A novel comprehensive 3D model is developed by considering the coupling interactions between vascular layers, and numerical simulations are carried out for a two-layer structure arterial wall. Results displayed the effects of dynamic viscosity on LDL transport. Moreover, we present data demonstrating that endothelial cells have a great blocking effect on the permeation and transmission of macromolecules by the different vascular wall. Furthermore, to verify the reliability and efficiency, a comparison is presented which shows that our numerical results are in good consistency with the experimental data in the literature. © Published under licence by IOP Publishing Ltd.

关键词： Endothelial cells

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Contributions to the Interannual Summer Rainfall Variability in the Mountainous Area of Central China and Their Decadal Changes

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Advances in Atmospheric sciences 2020年第3期37卷 259-268页

作者： Kaiming HU Yingxue LIU Gang HUANG Zhuoqi HE Shang-Min LONG Center for Monsoon System Research Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China State key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Joint Center for Global Change Studies(JCGCS) Beijing 100875China University of Chinese Academy of Sciences Beijing 100049China Laboratory for Regional Oceanography and Numerical Modeling Qingdao National Laboratory for Marine Science and TechnologyQingdao 266237China State Key Laboratory of Tropical Oceanography South China Sea Institute of OceanologyChinese Academy of SciencesGuangzhou 510301China College of Oceanography Hohai UniversityNanjing 210098China

Using a high-resolution precipitation dataset,the present study detected that the mountainous area of central China(MACA)is a hotspot of ENSO’s impact on the summer rainfall *** analysis suggests that both ENSO and atmospheric forcing make contributions to the summer rainfall variability in *** dominant rainfall-related SST mode features as a seasonal transition from an El Niño-like warming in the preceding winter to a La Nina-like cooling in the following autumn,and it explains about 29%of the total variance of the rainfall during 1951–*** indicates that ENSO with a rapid phase transition is responsible for inducing summer rainfall anomalies in ***,an upperlevel circumglobal wave mode in the Northern Hemisphere during summer also explains about 29%of the summer rainfall *** of both the SST and the atmospheric modes have experienced interdecadal *** influence of the SST mode gradually increases and plays a dominant role in the recent decades,suggesting that ENSO with a rapid phase transition becomes more important for rainfall prediction in MACA.

关键词： summer rainfall ENSO atmospheric internal variability interdecadal change

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