An analytical variational method for the ground state of the biased quantum Rabi model in the ultra-strong coupling regime is presented. This analytical variational method can be obtained by a unitary transformation o...An analytical variational method for the ground state of the biased quantum Rabi model in the ultra-strong coupling regime is presented. This analytical variational method can be obtained by a unitary transformation or alternatively by assuming the form of the ground state wave function. The key of the method is to introduce a variational parameter λ,which can be determined by minimizing the energy functional. Using this method, we calculate the physical observables with high accuracy in comparison with the numerical exact ones. Our method evidently improves over the widely used general rotating-wave approximation（GRWA） in both qualitative and quantitative aspects.展开更多
In this paper, we present a simple theoretical approach to calculate the multiple ionization of big atoms and molecules induced by very high-q fast projectiles in a strong coupling regime （q/v 〉 1）. The results obt...In this paper, we present a simple theoretical approach to calculate the multiple ionization of big atoms and molecules induced by very high-q fast projectiles in a strong coupling regime （q/v 〉 1）. The results obtained from this approach are in excellent agreement with the available experimental data. A probable scenario of molecular multiple ionization by fast and very high-q projectiles is discussed. The very small computational time required here and the good agreement with the existing experimental data make it a good candidate for studying the multiple ionization of complex molecules under high linear energy transfers.展开更多
We investigate the dynamics of two qubits coupled with a quantum oscillator by using the adiabatic approximation method. We take account of the interaction between the qubits and show how the entanglement is affected ...We investigate the dynamics of two qubits coupled with a quantum oscillator by using the adiabatic approximation method. We take account of the interaction between the qubits and show how the entanglement is affected by the interaction parameter. The most interesting result is that we can prolong the entanglement time or improve the entanglement degree by using an appropriate interaction parameter. As the generation and preservation of entanglement of qubits are crucial for quantum information processing, our research will be useful.展开更多
From the viewpoint of interaction mechanics for solid and gas, a coupled mathematical model was presented for solid coal/rock deformation and gas leak flow in parallel deformable coal seams. Numerical solutions using ...From the viewpoint of interaction mechanics for solid and gas, a coupled mathematical model was presented for solid coal/rock deformation and gas leak flow in parallel deformable coal seams. Numerical solutions using the SIP (Strong Implicit Proce- dure) method to the coupled mathematical model for double parallel coal seams were also developed in detail. Numerical simulations for the prediction of the safety range using protection layer mining were performed with experimental data from a mine with potential danger of coal/gas outbursts. Analyses show that the numerical simulation results are consistent with the measured data in situ.展开更多
Using adiabatic approximation, a two arbitrary qubits Rabi model has been studied in ultra-strong coupling. The analytical expressions of the eigenvalues and the eigenvalues are obtained. They are in accordance with t...Using adiabatic approximation, a two arbitrary qubits Rabi model has been studied in ultra-strong coupling. The analytical expressions of the eigenvalues and the eigenvalues are obtained. They are in accordance with the numerical determined results. The dynamical behavior of the system and the evolution of entanglement have also been discussed. The collapse and revival phenomena has garnered particular attention. The influence of inconsistent coupling strength on them is studied. These results will be applied in quantum information processing.展开更多
Strain localization frequently occurs in cohesive materials with friction(e.g.,composites,soils,rocks)and is widely recognized as a fundamental cause of progressive structural failure.Nonetheless,achieving high-fideli...Strain localization frequently occurs in cohesive materials with friction(e.g.,composites,soils,rocks)and is widely recognized as a fundamental cause of progressive structural failure.Nonetheless,achieving high-fidelity simulation for this issue,particularly concerning strong discontinuities and tension-compression-shear behaviors within localized zones,remains significantly constrained.In response,this study introduces an integrated algorithmwithin the finite element framework,merging a coupled cohesive zone model(CZM)with the nonlinear augmented finite elementmethod(N-AFEM).The coupledCZMcomprehensively describes tension-compression and compressionshear failure behaviors in cohesive,frictional materials,while the N-AFEM allows nonlinear coupled intraelement discontinuities without necessitating extra nodes or nodal DoFs.Following CZM validation using existing experimental data,this integrated algorithm was utilized to analyze soil slope failure mechanisms involving a specific tensile strength and to assess the impact of mechanical parameters(e.g.,tensile strength,weighting factor,modulus)in soils.展开更多
In this paper,we develop the teleportation scheme in[Zheng in Phys Rev A 69,064302,2004],in the sense that,we work in the strong atom-field coupling regime wherein the rotating wave approximation(RWA)is no longer vali...In this paper,we develop the teleportation scheme in[Zheng in Phys Rev A 69,064302,2004],in the sense that,we work in the strong atom-field coupling regime wherein the rotating wave approximation(RWA)is no longer valid.To achieve the purpose,a scheme consisting of a qubit interacting with a single-mode quantized field is described via the Rabi model(counter rotation terms are taken into account).Our first aim is to teleport an unknown atomic state of a qubit(which interacts with the quantized field in a cavity)to a second qubit(exists in another distant cavity field),beyond the RWA and without the Bell-state measurement method.In the continuation,in a similar way,we teleport an unknown state of a single-mode field too.In fact,it is shown that,in this regime,after applying some particular conditions,containing the interaction time of atom-field in the cavities,adjusting the involved frequencies,as well as the atom-field coupling in the model,if a proper measurement is performed on the state of the first qubit(the related field in the cavity),the unknown states of the qubit(field)can be teleported from the first qubit(cavity field)to the second qubit(cavity field),appropriately.We show that in both considered cases,the teleportation protocol is successfully performed with the maximum possible fidelity,1,and the acceptable success probability,0.25.展开更多
A new coupled map lattic (CML) model is given by using some stability analysis for the related difference equations. Numerical results show that the new model is an effective one of studying spatiotemporal chaos, espe...A new coupled map lattic (CML) model is given by using some stability analysis for the related difference equations. Numerical results show that the new model is an effective one of studying spatiotemporal chaos, especially for strongly coupled systems.展开更多
A novel variational approach is proposed to calculate the ground-state （GS） properties of the two-site Holstein model. By the linear superposition of two coherent states, which simulate the behaviour of the weak and...A novel variational approach is proposed to calculate the ground-state （GS） properties of the two-site Holstein model. By the linear superposition of two coherent states, which simulate the behaviour of the weak and strong coupling limits, we can obtain very accurate GS energy for arbitrary electron-phonon coupling constant. Other GS properties are also discussed. Moreover, the present concise approach is hopefully generalized to many other Holstein models.展开更多
The aim of this paper is the introduction of a new approach to 3D modelling of elastic piecewise homogeneous media, in particular Earth crust and upper Mantle. The method is based on the principle of tomography with E...The aim of this paper is the introduction of a new approach to 3D modelling of elastic piecewise homogeneous media, in particular Earth crust and upper Mantle. The method is based on the principle of tomography with Earthquake as a source of the signal and receiver stations on the surface. The wave propagation in solid media is described by a system of three strongly coupled hyperbolic equations with piece - wise constant coefitients. The characteristic set and hi-characteristic curves of this system are computed in a homogeneous half-space with free boundary and the formulae of reflection and diffraction of the hi-characteristics on the internal boundaries of the media. Applications of the characteristic set and bi-eharacteristic curves for the inverse problem in geophysics and Earth modelling are given.展开更多
Based on first-principles calculations within the framework of density functional theory, we study the electronic properties of phosphorene/graphene heterostructures. Band gaps with different sizes are observed in the...Based on first-principles calculations within the framework of density functional theory, we study the electronic properties of phosphorene/graphene heterostructures. Band gaps with different sizes are observed in the heterostructure, and charges transfer from graphene to phosphorene, causing the Fermi level of the heterostructure to shift downward with respect to the Dirac point of graphene. Significantly, strong coupling between two layers is discovered in the band spectrum even though it has a van der Waals heterostructure. A tight-binding Hamiltonian model is used to reveal that the resonance of the Bloch states between the phosphorene and graphene layers in certain K points combines with the symmetry matching between band states, which explains the reason for the strong coupling in such heterostructures. This work may enhance the understanding of interlayer interaction and composition mechanisms in van der Waals heterostructures consisting of two-dimensional layered nanomaterials, and may indicate potential reference information for nanoelectronic and optoelectronic applications.展开更多
The entanglement of two qubits is investigated in the range of their ultra-strongly coupling with a quantum oscillator. The two qubits are initially in four Bell states and they are under the control mechanism of the ...The entanglement of two qubits is investigated in the range of their ultra-strongly coupling with a quantum oscillator. The two qubits are initially in four Bell states and they are under the control mechanism of the coherent state of the quantum oscillator. There are four parameters: the average number of the coherent state, the ultra-strong coupling strength, the ratio of two frequencies of qubit and oscillator, and the inter-interaction coupling of the two qubits in the mechanism, and they all are influential parameters on the entanglement of the two qubits. One Bell state |0 is easyily kept and is trivial case. The novel results show that there is one state |I0 among the other three Bell states which the entanglement of the two qubits could be almost completely preserved. The possibility is made into reality by the appropriate choice of the four influential parameters. We give two different schemes to choose the respective parameters to maintain the entanglment of |I0 almost undiminished. The results will be useful for the quantum information process.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11674139,11604009,and 11704025)the Program for Changjiang Scholars and Innovative Research Team in University,China(Grant No.IRT-16R35)+1 种基金the Fundamental Research Funds for the Central Universities,Chinathe financial support of the Future and Emerging Technologies(FET)programme within the Seventh Framework Programme for Research of the European Commission,under FET-Open Grant No.618083(CNTQC)
文摘An analytical variational method for the ground state of the biased quantum Rabi model in the ultra-strong coupling regime is presented. This analytical variational method can be obtained by a unitary transformation or alternatively by assuming the form of the ground state wave function. The key of the method is to introduce a variational parameter λ,which can be determined by minimizing the energy functional. Using this method, we calculate the physical observables with high accuracy in comparison with the numerical exact ones. Our method evidently improves over the widely used general rotating-wave approximation（GRWA） in both qualitative and quantitative aspects.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11174116 and 11175075)
文摘In this paper, we present a simple theoretical approach to calculate the multiple ionization of big atoms and molecules induced by very high-q fast projectiles in a strong coupling regime （q/v 〉 1）. The results obtained from this approach are in excellent agreement with the available experimental data. A probable scenario of molecular multiple ionization by fast and very high-q projectiles is discussed. The very small computational time required here and the good agreement with the existing experimental data make it a good candidate for studying the multiple ionization of complex molecules under high linear energy transfers.
基金supported by the National Natural Science Foundation of China(Grant Nos.10875018 and 60578043)
文摘We investigate the dynamics of two qubits coupled with a quantum oscillator by using the adiabatic approximation method. We take account of the interaction between the qubits and show how the entanglement is affected by the interaction parameter. The most interesting result is that we can prolong the entanglement time or improve the entanglement degree by using an appropriate interaction parameter. As the generation and preservation of entanglement of qubits are crucial for quantum information processing, our research will be useful.
文摘From the viewpoint of interaction mechanics for solid and gas, a coupled mathematical model was presented for solid coal/rock deformation and gas leak flow in parallel deformable coal seams. Numerical solutions using the SIP (Strong Implicit Proce- dure) method to the coupled mathematical model for double parallel coal seams were also developed in detail. Numerical simulations for the prediction of the safety range using protection layer mining were performed with experimental data from a mine with potential danger of coal/gas outbursts. Analyses show that the numerical simulation results are consistent with the measured data in situ.
基金Project supported by the National Natural Science Foundation of China(Grant No.10875018)
文摘Using adiabatic approximation, a two arbitrary qubits Rabi model has been studied in ultra-strong coupling. The analytical expressions of the eigenvalues and the eigenvalues are obtained. They are in accordance with the numerical determined results. The dynamical behavior of the system and the evolution of entanglement have also been discussed. The collapse and revival phenomena has garnered particular attention. The influence of inconsistent coupling strength on them is studied. These results will be applied in quantum information processing.
基金supported by Zhejiang Provincial Natural Science Foundation of China under Grant Nos.LQ23E080001 and LTGG23E080002National Natural Science Foundation of China under Grant No.12272334Zhejiang Engineering Research Center of Intelligent Urban Infrastructure(No.IUI2023-YB-07).
文摘Strain localization frequently occurs in cohesive materials with friction(e.g.,composites,soils,rocks)and is widely recognized as a fundamental cause of progressive structural failure.Nonetheless,achieving high-fidelity simulation for this issue,particularly concerning strong discontinuities and tension-compression-shear behaviors within localized zones,remains significantly constrained.In response,this study introduces an integrated algorithmwithin the finite element framework,merging a coupled cohesive zone model(CZM)with the nonlinear augmented finite elementmethod(N-AFEM).The coupledCZMcomprehensively describes tension-compression and compressionshear failure behaviors in cohesive,frictional materials,while the N-AFEM allows nonlinear coupled intraelement discontinuities without necessitating extra nodes or nodal DoFs.Following CZM validation using existing experimental data,this integrated algorithm was utilized to analyze soil slope failure mechanisms involving a specific tensile strength and to assess the impact of mechanical parameters(e.g.,tensile strength,weighting factor,modulus)in soils.
文摘In this paper,we develop the teleportation scheme in[Zheng in Phys Rev A 69,064302,2004],in the sense that,we work in the strong atom-field coupling regime wherein the rotating wave approximation(RWA)is no longer valid.To achieve the purpose,a scheme consisting of a qubit interacting with a single-mode quantized field is described via the Rabi model(counter rotation terms are taken into account).Our first aim is to teleport an unknown atomic state of a qubit(which interacts with the quantized field in a cavity)to a second qubit(exists in another distant cavity field),beyond the RWA and without the Bell-state measurement method.In the continuation,in a similar way,we teleport an unknown state of a single-mode field too.In fact,it is shown that,in this regime,after applying some particular conditions,containing the interaction time of atom-field in the cavities,adjusting the involved frequencies,as well as the atom-field coupling in the model,if a proper measurement is performed on the state of the first qubit(the related field in the cavity),the unknown states of the qubit(field)can be teleported from the first qubit(cavity field)to the second qubit(cavity field),appropriately.We show that in both considered cases,the teleportation protocol is successfully performed with the maximum possible fidelity,1,and the acceptable success probability,0.25.
文摘A new coupled map lattic (CML) model is given by using some stability analysis for the related difference equations. Numerical results show that the new model is an effective one of studying spatiotemporal chaos, especially for strongly coupled systems.
基金Supported by the National Natural Science Foundation of China under Grant Nos 19804009 and 10274067.
文摘A novel variational approach is proposed to calculate the ground-state （GS） properties of the two-site Holstein model. By the linear superposition of two coherent states, which simulate the behaviour of the weak and strong coupling limits, we can obtain very accurate GS energy for arbitrary electron-phonon coupling constant. Other GS properties are also discussed. Moreover, the present concise approach is hopefully generalized to many other Holstein models.
文摘The aim of this paper is the introduction of a new approach to 3D modelling of elastic piecewise homogeneous media, in particular Earth crust and upper Mantle. The method is based on the principle of tomography with Earthquake as a source of the signal and receiver stations on the surface. The wave propagation in solid media is described by a system of three strongly coupled hyperbolic equations with piece - wise constant coefitients. The characteristic set and hi-characteristic curves of this system are computed in a homogeneous half-space with free boundary and the formulae of reflection and diffraction of the hi-characteristics on the internal boundaries of the media. Applications of the characteristic set and bi-eharacteristic curves for the inverse problem in geophysics and Earth modelling are given.
基金Thanks to Professor Zhipei Sun （Aalto University, Finland） for valuable discussions. This work was supported by the International Cooperative Program （Grant No. 2014DFR10780）, the National Natural Science Foundation of China （Grant No. 61275105）, tile Natural Science Foundation of Shaanxi Province （Grant No. 2014JM2-1008）, and the State Key Laboratory of Transient Optics and Photonic Technology 2015 An- nual Open Fund （Grant No. SKLST200915）.
文摘Based on first-principles calculations within the framework of density functional theory, we study the electronic properties of phosphorene/graphene heterostructures. Band gaps with different sizes are observed in the heterostructure, and charges transfer from graphene to phosphorene, causing the Fermi level of the heterostructure to shift downward with respect to the Dirac point of graphene. Significantly, strong coupling between two layers is discovered in the band spectrum even though it has a van der Waals heterostructure. A tight-binding Hamiltonian model is used to reveal that the resonance of the Bloch states between the phosphorene and graphene layers in certain K points combines with the symmetry matching between band states, which explains the reason for the strong coupling in such heterostructures. This work may enhance the understanding of interlayer interaction and composition mechanisms in van der Waals heterostructures consisting of two-dimensional layered nanomaterials, and may indicate potential reference information for nanoelectronic and optoelectronic applications.
基金Supported by the Major State Basic Research Development Program of China(973 Program:No.2010CB923202)the National Natural Science of China under Grant No.10875018
文摘The entanglement of two qubits is investigated in the range of their ultra-strongly coupling with a quantum oscillator. The two qubits are initially in four Bell states and they are under the control mechanism of the coherent state of the quantum oscillator. There are four parameters: the average number of the coherent state, the ultra-strong coupling strength, the ratio of two frequencies of qubit and oscillator, and the inter-interaction coupling of the two qubits in the mechanism, and they all are influential parameters on the entanglement of the two qubits. One Bell state |0 is easyily kept and is trivial case. The novel results show that there is one state |I0 among the other three Bell states which the entanglement of the two qubits could be almost completely preserved. The possibility is made into reality by the appropriate choice of the four influential parameters. We give two different schemes to choose the respective parameters to maintain the entanglment of |I0 almost undiminished. The results will be useful for the quantum information process.
