The brittleness analysis and important nodes detection have been a hot spot in the complex networks.How to get the overall feature of the whole network and how to find out some important nodes are requisites to solve ...The brittleness analysis and important nodes detection have been a hot spot in the complex networks.How to get the overall feature of the whole network and how to find out some important nodes are requisites to solve these problems. In this paper, we adopt the trace of the adjacency matrix and the centrality of the complex networks to give a quantitative and qualitative analysis of networks being studied. Results show that the k-shell plays a more important role than the degree centrality and the betweenness in finding important nodes, and it can also be used to give direction on the immunization and maintenance of complex networks.展开更多
Based on the model of a contaminated sea surface that was proposed by Lombardini et al., the influence of the damping effect of oil films on the sea surface roughness spectrum and the geometrical structure of the sea ...Based on the model of a contaminated sea surface that was proposed by Lombardini et al., the influence of the damping effect of oil films on the sea surface roughness spectrum and the geometrical structure of the sea surface is examined in detail by comparing with a clean sea surface. Fhrthermore, based on a quasi-stationary algorithm, a time series of backscattered echoes from a time-evolving sea surface covered by oil slicks is obtained by utilizing the frequency-domain numerical method of the parallel fast multiple method. Then, the Doppler spectrum is evaluated by performing a standard spectral estimation technique. Finally, the influence of the oil film damping effect on the Doppler spectrum of the backscattered echoes from time-evolving sea surface is investigated in detail by making a comparison of the Doppler spectrum of an oil-covered sea surface with the Doppler spectrum of a dean sea surface. The numerical simulations show that the damping effect of oil films has an influence on the Doppler spectrum signature for both horizontal-to-horizontal and vertical-to-vertical polarizations.展开更多
The infinite time-evolving block decimation algorithm(i TEBD)provides an efficient way to determine the ground state and dynamics of the quantum lattice systems in the thermodynamic limit.In this paper we suggest an o...The infinite time-evolving block decimation algorithm(i TEBD)provides an efficient way to determine the ground state and dynamics of the quantum lattice systems in the thermodynamic limit.In this paper we suggest an optimized way to take the i TEBD calculation,which takes advantage of additional reduced decompositions to speed up the calculation.The numerical calculations show that for a comparable computation time our method provides more accurate results than the traditional i TEBD,especially for lattice systems with large on-site degrees of freedom.展开更多
Correcting wavefront distortion caused by atmospheric turbulence is crucial for atmospheric optics.To evaluate correction systems,a real and fast atmospheric turbulence time-evolving model is needed.We proposed a mode...Correcting wavefront distortion caused by atmospheric turbulence is crucial for atmospheric optics.To evaluate correction systems,a real and fast atmospheric turbulence time-evolving model is needed.We proposed a model for a time-evolving turbulence phase screen(PS)based on its fractal nature,which achieves scale transformation under time or space.According to fractional Brownian motion,an interpolation algorithm is proposed to enhance the spatio-temporal resolution of PS efficiently.Additionally,a grid-based time-evolving PS generation method is proposed combining the covariance matrix and temporal spectra.The results demonstrate that our method can efficiently generate time-evolving PS with high spatio-temporal resolution and accuracy,and the interpolation algorithm introduces a slight deviation of less than 2%,which has a minimal impact on the overall results.The fractal nature of atmospheric turbulence has enabled the generation of PS with high accuracy,efficiency,and flexibility.This advancement is meaningful for atmospheric turbulence simulation and related atmospheric optics fields.展开更多
An approach for time-evolving sound speed profiles tracking in shallow water is discussed. The inversion of time-evolving sound speed profiles is modeled as a state-space estimation problem, which includes a state equ...An approach for time-evolving sound speed profiles tracking in shallow water is discussed. The inversion of time-evolving sound speed profiles is modeled as a state-space estimation problem, which includes a state equation for predicting the time-evolving sound speed profile and a measurement equation for incorporating local acoustic measurements. In the paper, auto-regression （AR） method is introduced to obtain a high-order AR evolution model of the sound speed field time variations, and the ensemble Kalman filter is utilized to track the sound speed field. To validate the approach, the accuracy in sound speed estimation is analyzed via a numerical implementation using the ASIAEX experimental environment and the sound velocity measurement data. Compared with traditional approaches based on the state evolution represented as a random walk, simulation results show the proposed AR method can effectively reduce the tracking errors of sound speed, and still keep good tracking performance at low signal-to-noise ratios.展开更多
We study the critical scaling and dynamical signatures of fractionalized excitations at two different deconfined quantum critical points(DQCPs)in an S=1/2 spin chain using the time evolution of infinite matrix product...We study the critical scaling and dynamical signatures of fractionalized excitations at two different deconfined quantum critical points(DQCPs)in an S=1/2 spin chain using the time evolution of infinite matrix product states.The scaling of the correlation functions and the dispersion of the conserved current correlations explicitly show the emergence of enhanced continuous symmetries at these DQCPs.The dynamical structure factors in several different channels reveal the development of deconfined fractionalized excitations at the DQCPs.Furthermore,we find an effective spin-charge separation at the DQCP between the ferromagnetic(FM)and valence bond solid(VBS)phases,and identify two continua associated with different types of fractionalized excitations at the DQCP between the X-direction and Z-direction FM phases.Our findings not only provide direct evidence for the DQCP in one dimension but also shed light on exploring the DQCP in higher dimensions.展开更多
The ground-state phase diagram and nonlocal order parameters of an infinite spin tetrahedron chain with inhomogeneous exchange couplings are investigated.It is shown that the phase boundaries of the three phases in th...The ground-state phase diagram and nonlocal order parameters of an infinite spin tetrahedron chain with inhomogeneous exchange couplings are investigated.It is shown that the phase boundaries of the three phases in the model can be determined precisely,in line with the precision of its ground-state energy.Numerical calculations using the regularized time-evolving block decimation(rTEBD)algorithm yield the locations of the two quantum critical points with an accuracy about 10 digits.Moreover,we explain how to calculate the parity-associated string order for the output wave function obtained through the rTEBD procedure,which not only reveals the presence of long-range correlations but also identifies the symmetry-protected topological order within the intermediate phase of the model.展开更多
文摘The brittleness analysis and important nodes detection have been a hot spot in the complex networks.How to get the overall feature of the whole network and how to find out some important nodes are requisites to solve these problems. In this paper, we adopt the trace of the adjacency matrix and the centrality of the complex networks to give a quantitative and qualitative analysis of networks being studied. Results show that the k-shell plays a more important role than the degree centrality and the betweenness in finding important nodes, and it can also be used to give direction on the immunization and maintenance of complex networks.
基金Supported by the National Science Foundation for Distinguished Young Scholars of China under Grant No 61225002the Aeronautical Science Fund and Aviation Key Laboratory of Science and Technology on AISSS of China under Grant No20132081015
文摘Based on the model of a contaminated sea surface that was proposed by Lombardini et al., the influence of the damping effect of oil films on the sea surface roughness spectrum and the geometrical structure of the sea surface is examined in detail by comparing with a clean sea surface. Fhrthermore, based on a quasi-stationary algorithm, a time series of backscattered echoes from a time-evolving sea surface covered by oil slicks is obtained by utilizing the frequency-domain numerical method of the parallel fast multiple method. Then, the Doppler spectrum is evaluated by performing a standard spectral estimation technique. Finally, the influence of the oil film damping effect on the Doppler spectrum of the backscattered echoes from time-evolving sea surface is investigated in detail by making a comparison of the Doppler spectrum of an oil-covered sea surface with the Doppler spectrum of a dean sea surface. The numerical simulations show that the damping effect of oil films has an influence on the Doppler spectrum signature for both horizontal-to-horizontal and vertical-to-vertical polarizations.
基金Project supported by Fundamental Research Funds for the Central Universities(Grant No.FRF-TP-19-013A3)。
文摘The infinite time-evolving block decimation algorithm(i TEBD)provides an efficient way to determine the ground state and dynamics of the quantum lattice systems in the thermodynamic limit.In this paper we suggest an optimized way to take the i TEBD calculation,which takes advantage of additional reduced decompositions to speed up the calculation.The numerical calculations show that for a comparable computation time our method provides more accurate results than the traditional i TEBD,especially for lattice systems with large on-site degrees of freedom.
基金supported by the National Natural Science Foundation of China(Nos.62371437,62271463,and 62171424)the Fundamental Research Funds for the Central Universities(No.KY2470000006)the Innovation Program for Quantum Science and Technology(No.2021ZD0300701)。
文摘Correcting wavefront distortion caused by atmospheric turbulence is crucial for atmospheric optics.To evaluate correction systems,a real and fast atmospheric turbulence time-evolving model is needed.We proposed a model for a time-evolving turbulence phase screen(PS)based on its fractal nature,which achieves scale transformation under time or space.According to fractional Brownian motion,an interpolation algorithm is proposed to enhance the spatio-temporal resolution of PS efficiently.Additionally,a grid-based time-evolving PS generation method is proposed combining the covariance matrix and temporal spectra.The results demonstrate that our method can efficiently generate time-evolving PS with high spatio-temporal resolution and accuracy,and the interpolation algorithm introduces a slight deviation of less than 2%,which has a minimal impact on the overall results.The fractal nature of atmospheric turbulence has enabled the generation of PS with high accuracy,efficiency,and flexibility.This advancement is meaningful for atmospheric turbulence simulation and related atmospheric optics fields.
基金supported by the National Natural Science Foundation of China(41576103)
文摘An approach for time-evolving sound speed profiles tracking in shallow water is discussed. The inversion of time-evolving sound speed profiles is modeled as a state-space estimation problem, which includes a state equation for predicting the time-evolving sound speed profile and a measurement equation for incorporating local acoustic measurements. In the paper, auto-regression （AR） method is introduced to obtain a high-order AR evolution model of the sound speed field time variations, and the ensemble Kalman filter is utilized to track the sound speed field. To validate the approach, the accuracy in sound speed estimation is analyzed via a numerical implementation using the ASIAEX experimental environment and the sound velocity measurement data. Compared with traditional approaches based on the state evolution represented as a random walk, simulation results show the proposed AR method can effectively reduce the tracking errors of sound speed, and still keep good tracking performance at low signal-to-noise ratios.
基金Project supported by the National Science Foundation of China(Grant No.12174441)the Fundamental Research Funds for the Central Universities,Chinathe Research Funds of Remnin University of China(Grant No.18XNLG24)。
文摘We study the critical scaling and dynamical signatures of fractionalized excitations at two different deconfined quantum critical points(DQCPs)in an S=1/2 spin chain using the time evolution of infinite matrix product states.The scaling of the correlation functions and the dispersion of the conserved current correlations explicitly show the emergence of enhanced continuous symmetries at these DQCPs.The dynamical structure factors in several different channels reveal the development of deconfined fractionalized excitations at the DQCPs.Furthermore,we find an effective spin-charge separation at the DQCP between the ferromagnetic(FM)and valence bond solid(VBS)phases,and identify two continua associated with different types of fractionalized excitations at the DQCP between the X-direction and Z-direction FM phases.Our findings not only provide direct evidence for the DQCP in one dimension but also shed light on exploring the DQCP in higher dimensions.
基金supported by the National Natural Science Foundation of China(Grant No.12471443).
文摘The ground-state phase diagram and nonlocal order parameters of an infinite spin tetrahedron chain with inhomogeneous exchange couplings are investigated.It is shown that the phase boundaries of the three phases in the model can be determined precisely,in line with the precision of its ground-state energy.Numerical calculations using the regularized time-evolving block decimation(rTEBD)algorithm yield the locations of the two quantum critical points with an accuracy about 10 digits.Moreover,we explain how to calculate the parity-associated string order for the output wave function obtained through the rTEBD procedure,which not only reveals the presence of long-range correlations but also identifies the symmetry-protected topological order within the intermediate phase of the model.
