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Dynamics of Jaynes-Cummings Model in the Absence of Rotating-Wave Approximation 被引量:2
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作者 FAN Yun-Xia LIU Tao +1 位作者 FENG Mang WANG Ke-Lin 《Communications in Theoretical Physics》 SCIE CAS CSCD 2007年第5期781-786,共6页
The Jaynes-Cummings model (JCM) is studied in the absence of the rotating-wave approximation (RWA) by a coherent-state expansion technique. In comparison with the previous paper in which the coherent-state expansi... The Jaynes-Cummings model (JCM) is studied in the absence of the rotating-wave approximation (RWA) by a coherent-state expansion technique. In comparison with the previous paper in which the coherent-state expansion was performed only to the third order, we carry out in this paper a complete expansion to demonstrate exactly the dynamics of the JCM without the RWA. Our study gives a systematic method to solve the non-RWA problem, which would be useful in various physical systems, e.g., in a system with an ultracold trapped ion experiencing the running waves of lasers. 展开更多
关键词 coherent-state expansion rotating-wave approximation (RWA) Jaynes-Cummings model (JCM)
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Weak-Coupling Theory for Semiclassical Periodically Driven Two-Level Systems: Beyond Rotating-Wave Approximation 被引量:2
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作者 YANG Xiao-Xue WU Ying 《Communications in Theoretical Physics》 SCIE CAS CSCD 2007年第2X期339-342,共4页
We present a weak-coupling theory of semiclassical periodically driven two-level systems. The explicit analytical approximating solution is shown to reproduce highly accurately the exact results well beyond the regime... We present a weak-coupling theory of semiclassical periodically driven two-level systems. The explicit analytical approximating solution is shown to reproduce highly accurately the exact results well beyond the regime of the rotating-wave approximation. 展开更多
关键词 periodically driven two-level systems weak-coupling theory beyond rotating-wave approximation
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Geometric phases in qubit-oscillator system beyond conventional rotating-wave approximation
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作者 王月明 杜冠 梁九卿 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第4期319-323,共5页
In this work we investigated the geometric phases of a qubit-oscillator system beyond the conventional rotating- wave approximation. We find that in the limiting of weak coupling the results coincide with that obtaine... In this work we investigated the geometric phases of a qubit-oscillator system beyond the conventional rotating- wave approximation. We find that in the limiting of weak coupling the results coincide with that obtained under rotating-wave approximation while there exists an increasing difference with the increase of coupling constant. It was shown that the geometric phase is symmetric with respect to the sign of the detuning of the quantized field from the one-photon resonance under the conventional rotating-wave approximation while a red-blue detuning asymmetry occurs beyond the conventional rotating-wave approximation. 展开更多
关键词 geometric phase rotating-wave approximation red-blue detuning asymmetry
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Entanglement evolution of a two-qubit system with decay beyond the rotating-wave approximation
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作者 杨青 杨名 +1 位作者 李大创 曹卓良 《Chinese Physics B》 SCIE EI CAS CSCD 2009年第11期4662-4666,共5页
The entanglement property of two identical atoms, initially entangled in Bell states, coupled to a single-mode cavity is considered. Based on the reduced non-perturbative quantum master equation method, the entangleme... The entanglement property of two identical atoms, initially entangled in Bell states, coupled to a single-mode cavity is considered. Based on the reduced non-perturbative quantum master equation method, the entanglement evolution of the two atoms with decay is investigated beyond the conventional rotating-wave approximation. We show that the counter-rotating wave terms, usually neglected, have a great influence on the disentanglement behaviour of the system. The phenomena of entanglement sudden death and entanglement sudden birth will occur. In addition, we show that the entanglement can be strengthened by introducing the dipole-dipole interaction of the two atoms. 展开更多
关键词 quantum entanglement beyond rotating-wave approximation
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Formalism of rotating-wave approximation in high-spin system with quadrupole interaction
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作者 丁文魁 王晓光 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第3期72-78,共7页
We investigate the rotating wave approximation applied in the high-spin quantum system driven by a linearly polarized alternating magnetic field in the presence of quadrupole interactions.The conventional way to apply... We investigate the rotating wave approximation applied in the high-spin quantum system driven by a linearly polarized alternating magnetic field in the presence of quadrupole interactions.The conventional way to apply the rotating wave approximation in a driven high-spin system is to assume the dynamics being restricted in the reduced Hilbert space.However,when the driving strength is relatively strong or the driving is off resonant,the leakage from the target resonance subspace cannot be neglected for a multi-level quantum system.We propose the correct formalism to apply the rotating wave approximation in the full Hilbert space by taking this leakage into account.By estimating the operator fidelity of the time propagator,our formalism applied in the full Hilbert space unambiguously manifests great advantages over the conventional method applied in the reduced Hilbert space. 展开更多
关键词 rotating wave approximation quadrupole interaction high-spin system
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Effective Hamiltonian of the Jaynes–Cummings model beyond rotating-wave approximation
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作者 Yi-Fan Wang Hong-Hao Yin +2 位作者 Ming-Yue Yang An-Chun Ji Qing Sun 《Chinese Physics B》 SCIE EI CAS CSCD 2021年第6期300-305,共6页
The Jaynes–Cummings model with or without rotating-wave approximation plays a major role to study the interaction between atom and light. We investigate the Jaynes–Cummings model beyond the rotating-wave approximati... The Jaynes–Cummings model with or without rotating-wave approximation plays a major role to study the interaction between atom and light. We investigate the Jaynes–Cummings model beyond the rotating-wave approximation. Treating the counter-rotating terms as periodic drivings, we solve the model in the extended Floquet space. It is found that the full energy spectrum folded in the quasi-energy bands can be described by an effective Hamiltonian derived in the highfrequency regime. In contrast to the Z_(2) symmetry of the original model, the effective Hamiltonian bears an enlarged U(1)symmetry with a unique photon-dependent atom-light detuning and coupling strength. We further analyze the energy spectrum, eigenstate fidelity and mean photon number of the resultant polaritons, which are shown to be in accordance with the numerical simulations in the extended Floquet space up to an ultra-strong coupling regime and are not altered significantly for a finite atom-light detuning. Our results suggest that the effective model provides a good starting point to investigate the rich physics brought by counter-rotating terms in the frame of Floquet theory. 展开更多
关键词 Jaynes–Cummings model Floquet theory high-frequency approximation
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An Approximation Method for Singular Trudinger-Moser Inequality
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作者 ZHU Maochun XU Wenyan JIANG Rou 《应用数学》 北大核心 2025年第1期64-70,共7页
In this paper,we construct a power type functional which is the approximation functional of the Singular Trudinger-Moser functional.Moreover,we obtain the concentration level of the functional and show it converges to... In this paper,we construct a power type functional which is the approximation functional of the Singular Trudinger-Moser functional.Moreover,we obtain the concentration level of the functional and show it converges to the concentration level of singular Trudinger-Moser functional on the unit ball. 展开更多
关键词 Singular Trudinger-Moser inequality approximation functional Concentration level
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Statistical analysis on the validity of the cold plasma approximation for chorus waves based on Van Allen Probe observations and their effects on radiation belt electrons
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作者 AoJun Ren Jiang Yu +2 位作者 Jing Wang ZuZheng Chen XiaoMan Liu 《Earth and Planetary Physics》 EI CAS 2025年第1期159-170,共12页
Theoretical analysis has demonstrated that the dispersion relation of chorus waves plays an essential role in the resonant interaction and energy transformation between the waves and magnetospheric electrons.Previous ... Theoretical analysis has demonstrated that the dispersion relation of chorus waves plays an essential role in the resonant interaction and energy transformation between the waves and magnetospheric electrons.Previous quantitative analyses often simplified the chorus dispersion relation by using the cold plasma assumption.However,the applicability of the cold plasma assumption is doubtful,especially during geomagnetic disturbances.We here present a systematic statistical analysis on the validity of the cold plasma dispersion relation of chorus waves based on observations from the Van Allen Probes over the period from 2012 to 2018.The statistical results show that the observed magnetic field intensities deviate substantially from those calculated from the cold plasma dispersion relation and that they become more pronounced with an increase in geomagnetic activity or a decrease in background plasma density.The region with large deviations is mainly concentrated in the nightside and expands in both the radial and azimuthal directions as the geomagnetic activity increases or the background plasma density decreases.In addition,the bounce-averaged electron scattering rates are computed by using the observed and cold plasma dispersion relation of chorus waves.Compared with usage of the cold plasma dispersion relation,usage of the observed dispersion relation considerably lowers the minimum resonant energy of electrons and lowers the scattering rates of electrons above tens of kiloelectronvolts but enhances those below.Furthermore,these differences are more pronounced with the enhancement of geomagnetic activity or the decrease in background plasma density. 展开更多
关键词 chorus waves cold plasma approximation dispersion relations scattering rates
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Exceptional Set for Diophantine Approximation with Primes of Two Squares and Three Biquadrates
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作者 LIU Minmin ZHANG Min LI Jinjiang 《数学进展》 北大核心 2025年第1期18-36,共19页
Suppose thatλ_(1),λ_(2),λ_(3),λ_(4),λ_(5)are nonzero real numbers,not all of the same sign,andλ_(1)/λ_(2)is irrational and algebraic.Let V be a well-spaced sequence,δ>0.In this paper,it is proved that,for ... Suppose thatλ_(1),λ_(2),λ_(3),λ_(4),λ_(5)are nonzero real numbers,not all of the same sign,andλ_(1)/λ_(2)is irrational and algebraic.Let V be a well-spaced sequence,δ>0.In this paper,it is proved that,for anyε>0,the number of v∈V with v≤N such that the following inequality|λ_(1)p_(1)~2+λ_(2)p_(2)~2+λ_(3)p_(3)~4+λ_(4)p_(4)~4+λ_5p_5~4-v|<v^(-δ)has no solution in prime variables p_(1),p_(2),p_(3),p_(4),p_(5)does not exceed O(N^(29/32+2δ+ε)). 展开更多
关键词 Diophantine approximation exponential sum Davenport-Heilbronn method prime variable
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Smoluchowski-Kramers Approximation for Stochastic Differential Equations under Discretization
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作者 Li Ge 《应用概率统计》 北大核心 2025年第4期622-635,共14页
This paper studies the Smoluchowski–Kramers approximation for a discrete-time dynamical system modeled as the motion of a particle in a force field.We show that the approximation holds for the drift-implicit Euler–M... This paper studies the Smoluchowski–Kramers approximation for a discrete-time dynamical system modeled as the motion of a particle in a force field.We show that the approximation holds for the drift-implicit Euler–Maruyama discretization and derive its convergence rate.In particular,the solution of the discretized system converges to the solution of the first-order limit equation in the mean-square sense,and this convergence is independent of the order in which the mass parameterμand the step size h tend to zero. 展开更多
关键词 stochastic differential equations Smoluchowski-Kramers approximation driftimplicit Euler-Maruyama scheme convergence rate
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A reconfigurable array with adaptive approximation using dual threshold accuracy
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作者 SHAN Rui SONG Yupeng LIAO Wang 《High Technology Letters》 2025年第3期226-237,共12页
With the growing demand for compute-intensive applications such as artificial intelligence(AI)and video processing,traditional reconfigurable array processors fail to meet the requirements of high-performance computin... With the growing demand for compute-intensive applications such as artificial intelligence(AI)and video processing,traditional reconfigurable array processors fail to meet the requirements of high-performance computing and related domains,primarily due to their high power consumption and low energy efficiency.To address this limitation,this paper proposes an accuracy-adaptive approxi-mate reconfigurable array architecture featuring preset dual thresholds and support for four computa-tional accuracy levels,enabling flexible adaptation to diverse application needs.The architecture in-tegrates a self-adaptive mechanism that dynamically adjusts computational precision based on real-time error threshold feedback.To evaluate the proposed architecture,the you only look once version 5(YOLOv5)deep neural network algorithm is parallelized and deployed on the approximate recon-figurable array.Experimental results demonstrate that the architecture achieves an 18.93%reduc-tion in power consumption compared with conventional reconfigurable structures operating in full-pre-cision mode.Additionally,the design exhibits superior energy efficiency and reduced computational resource utilization,thereby significantly enhancing the overall performance and applicability of reconfigurable array processors in power-sensitive scenarios. 展开更多
关键词 reconfigurable computing approximate computing low power ENERGY-EFFICIENT
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On approximation of Bernstein-Stancu operators in movable interval
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作者 WAGN Feng-feng YU Dan-sheng 《Applied Mathematics(A Journal of Chinese Universities)》 2025年第1期85-101,共17页
In the present paper,we obtain the converse results of approximation of a newly introduced genuine Bernstein-Durrmeyer operators in movable interval.We also get the moments properties of an auxiliary operator which ha... In the present paper,we obtain the converse results of approximation of a newly introduced genuine Bernstein-Durrmeyer operators in movable interval.We also get the moments properties of an auxiliary operator which has its own independent values.The moments of the auxiliary operators play important roles in establishing the main result(Theorem 4). 展开更多
关键词 Bernstein-Stancu operators movable interval approximation rates Voronovskaja's asymptotic estimate
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Optimal convex approximations of qubit states based on l_(1)-norm of coherence
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作者 Li-Qiang Zhang Yan-Dong Du Chang-Shui Yu 《Chinese Physics B》 2025年第8期475-491,共17页
Determining the minimal distance between the target state and the convex combination of given states is a fundamental problem in quantum resource theory,offering critical guidance for experimental implementations.In t... Determining the minimal distance between the target state and the convex combination of given states is a fundamental problem in quantum resource theory,offering critical guidance for experimental implementations.In this paper,we embark on an in-depth exploration of the use of a quantum state prepared by the convex combination of given qubit states to optimally approximate the l_(1)-norm of coherence of the target quantum state,striving to make the prepared state and the target state as similar as possible.Here,we present the analytical solution for the optimal distance for any N given quantum states.We find that the optimal approximation problem for any N>4 quantum states can be transformed into an optimal approximation problem for no more than four quantum states,which not only significantly streamlines the problem but also proves advantageous for laboratories in terms of material conservation.Ultimately,a one-to-one comparison between the analytical and numerical solutions verifies the effectiveness of our approach. 展开更多
关键词 quantum information processing quantum resource theory quantum coherence optimal convex approximations
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Multi-Interval-Aggregation Failure Point Approximation for Remaining Useful Life Prediction
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作者 Linchuan Fan Xiaolong Chen +1 位作者 Shuo Li Yi Chai 《IEEE/CAA Journal of Automatica Sinica》 2025年第3期639-641,共3页
Dear Editor,This letter focuses on the remaining useful life(RUL)prediction task under limited labeled samples.Existing machine-learning-based RUL prediction methods for this task usually pay attention to mining degra... Dear Editor,This letter focuses on the remaining useful life(RUL)prediction task under limited labeled samples.Existing machine-learning-based RUL prediction methods for this task usually pay attention to mining degradation information to improve the prediction accuracy of degradation value or health indicator for the next epoch.However,they ignore the cumulative prediction error caused by iterations before reaching the failure point. 展开更多
关键词 remaining useful life prediction failure point degradation value health indicator multi interval aggregation failure point approximation machine learning based mining degradation information
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Fast Ion Gates without the Lamb-Dicke Approximation by Robust Quantum Optimal Control
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作者 Ran Liu Xiaodong Yang +2 位作者 Yiheng Lin Yao Lu Jun Li 《Chinese Physics Letters》 2025年第8期75-82,共8页
We present a robust quantum optimal control framework for implementing fast entangling gates on ion-trap quantum processors.The framework leverages tailored laser pulses to drive the multiple vibrational sidebands of ... We present a robust quantum optimal control framework for implementing fast entangling gates on ion-trap quantum processors.The framework leverages tailored laser pulses to drive the multiple vibrational sidebands of the ions to create phonon-mediated entangling gates and,unlike the state of the art,requires neither weakcoupling Lamb-Dicke approximation nor perturbation treatment.With the application of gradient-based optimal control,it enables finding amplitude-and phase-modulated laser control protocols that work without the Lamb-Dicke approximation,promising gate speeds on the order of microseconds comparable to the characteristic trap frequencies.Also,robustness requirements on the temperature of the ions and initial optical phase can be conveniently included to pursue high-quality fast gates against experimental imperfections.Our approach represents a step in speeding up quantum gates to achieve larger quantum circuits for quantum computation and simulation,and thus can find applications in near-future experiments. 展开更多
关键词 quantum optimal control framework gradient based optimal control quantum computation Lamb Dicke approximation fast ion gates tailored laser pulses entangling gates robust quantum optimal control
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An Overview of Sequential Approximation in Topology Optimization of Continuum Structure 被引量:1
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作者 Kai Long Ayesha Saeed +6 位作者 Jinhua Zhang Yara Diaeldin Feiyu Lu Tao Tao Yuhua Li Pengwen Sun Jinshun Yan 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第4期43-67,共25页
This paper offers an extensive overview of the utilization of sequential approximate optimization approaches in the context of numerically simulated large-scale continuum structures.These structures,commonly encounter... This paper offers an extensive overview of the utilization of sequential approximate optimization approaches in the context of numerically simulated large-scale continuum structures.These structures,commonly encountered in engineering applications,often involve complex objective and constraint functions that cannot be readily expressed as explicit functions of the design variables.As a result,sequential approximation techniques have emerged as the preferred strategy for addressing a wide array of topology optimization challenges.Over the past several decades,topology optimization methods have been advanced remarkably and successfully applied to solve engineering problems incorporating diverse physical backgrounds.In comparison to the large-scale equation solution,sensitivity analysis,graphics post-processing,etc.,the progress of the sequential approximation functions and their corresponding optimizersmake sluggish progress.Researchers,particularly novices,pay special attention to their difficulties with a particular problem.Thus,this paper provides an overview of sequential approximation functions,related literature on topology optimization methods,and their applications.Starting from optimality criteria and sequential linear programming,the other sequential approximate optimizations are introduced by employing Taylor expansion and intervening variables.In addition,recent advancements have led to the emergence of approaches such as Augmented Lagrange,sequential approximate integer,and non-gradient approximation are also introduced.By highlighting real-world applications and case studies,the paper not only demonstrates the practical relevance of these methods but also underscores the need for continued exploration in this area.Furthermore,to provide a comprehensive overview,this paper offers several novel developments that aim to illuminate potential directions for future research. 展开更多
关键词 Topology optimization sequential approximate optimization convex linearization method ofmoving asymptotes sequential quadratic programming
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Design of a 14-Bit 1 MS/s Successive Approximation Analog-to-Digital Converter 被引量:1
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作者 Qinghong Li Xianguo Cao +1 位作者 Liangbin Wang Mingjun Song 《Journal of Power and Energy Engineering》 2024年第11期59-71,共13页
A 14-bit successive approximation analog-to-digital converter (SAR ADC) with capacitive calibration has been designed based on the SMIC. 18 μm CMOS process. The overall architecture is in fully differential form to e... A 14-bit successive approximation analog-to-digital converter (SAR ADC) with capacitive calibration has been designed based on the SMIC. 18 μm CMOS process. The overall architecture is in fully differential form to eliminate the effect caused by common mode noise. Meanwhile, the digital-to-analog converter (DAC) is a two-stage structure, which can greatly reduce the area of the capacitor array compared with the traditional DAC structure. The capacitance calibration module is mainly divided into the mismatch voltage acquisition phase and the calibration code backfill phase, which effectively reduces the impact of the DAC mismatch on the accuracy of the SAR ADC. The design of this paper is based on cadence platform simulation verification, simulation results show that when the sampling rate is 1 MS/s, the power supply voltage is 5 V and the reference voltage is 4.096 V, the effective number of bits (ENOB) of the ADC is 13.49 bit, and the signal-to-noise ratio (SNR) is 83.3 dB. 展开更多
关键词 Analog-to-Digital Converter Capacitor Mismatch CALIBRATION Successive approximation
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Evolutionary Safe Padé Approximation Scheme for Dynamical Study of Nonlinear Cervical Human Papilloma Virus Infection Model
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作者 Javaid Ali Armando Ciancio +4 位作者 Kashif Ali Khan Nauman Raza Haci Mehmet Baskonus Muhammad Luqman Zafar-Ullah Khan 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第9期2275-2296,共22页
This study proposes a structure-preserving evolutionary framework to find a semi-analytical approximate solution for a nonlinear cervical cancer epidemic(CCE)model.The underlying CCE model lacks a closed-form exact so... This study proposes a structure-preserving evolutionary framework to find a semi-analytical approximate solution for a nonlinear cervical cancer epidemic(CCE)model.The underlying CCE model lacks a closed-form exact solution.Numerical solutions obtained through traditional finite difference schemes do not ensure the preservation of the model’s necessary properties,such as positivity,boundedness,and feasibility.Therefore,the development of structure-preserving semi-analytical approaches is always necessary.This research introduces an intelligently supervised computational paradigm to solve the underlying CCE model’s physical properties by formulating an equivalent unconstrained optimization problem.Singularity-free safe Padérational functions approximate the mathematical shape of state variables,while the model’s physical requirements are treated as problem constraints.The primary model of the governing differential equations is imposed to minimize the error between approximate solutions.An evolutionary algorithm,the Genetic Algorithm with Multi-Parent Crossover(GA-MPC),executes the optimization task.The resulting method is the Evolutionary Safe PadéApproximation(ESPA)scheme.The proof of unconditional convergence of the ESPA scheme on the CCE model is supported by numerical simulations.The performance of the ESPA scheme on the CCE model is thoroughly investigated by considering various orders of non-singular Padéapproximants. 展开更多
关键词 Nonlinear cervical cancer epidemic non-singular Padéapproximants approximate solutions computational biology
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Eikonal approximation for Floquet scattering
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作者 Yaru Liu Peng Zhang 《Communications in Theoretical Physics》 SCIE CAS CSCD 2024年第11期48-53,共6页
The eikonal approximation(EA)is widely used in various high-energy scattering problems.In this work we generalize this approximation from the scattering problems with time-independent Hamiltonian to the ones with peri... The eikonal approximation(EA)is widely used in various high-energy scattering problems.In this work we generalize this approximation from the scattering problems with time-independent Hamiltonian to the ones with periodical Hamiltonians,i.e.,the Floquet scattering problems.We further illustrate the applicability of our generalized EA via the scattering problem with respect to a shaking spherical square-well potential,by comparing the results given by this approximation and the exact ones.The generalized EA we developed is helpful for the research of manipulation of high-energy scattering processes with external field,e.g.the manipulation of atom,molecule or nuclear collisions or reactions via strong laser fields. 展开更多
关键词 Eikonal approximation Floquet Scattering high-energy scattering
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The Degree of Approximation by(E,q)(C,α,β)Means in Orlicz Spaces
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作者 CHEN Lin WU Ga-ridi 《Chinese Quarterly Journal of Mathematics》 2024年第4期399-406,共8页
In this paper,we study the trigonometric approximation problems of functions which belong to the Lipαclass,the Lip(ξ(t))class,and the W(L_(M)^(*);ξ(t))class in Orlicz spaces by using the tools Hölder inequalit... In this paper,we study the trigonometric approximation problems of functions which belong to the Lipαclass,the Lip(ξ(t))class,and the W(L_(M)^(*);ξ(t))class in Orlicz spaces by using the tools Hölder inequality in Orlicz spaces,the second mean value theorem for integrals,and(E,q)(C,α,β)means etc.At the same time,we give the corresponding degree of approximation. 展开更多
关键词 Orlice space Trigonometric approximation Degree of approximation
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