We propose an efficient scheme to generate a macroscopical quantum superposition state with a cavity optomechanical system,which is composed of a quantum Rabi-Stark model coupling to a mechanical oscillator.In a low-e...We propose an efficient scheme to generate a macroscopical quantum superposition state with a cavity optomechanical system,which is composed of a quantum Rabi-Stark model coupling to a mechanical oscillator.In a low-energy subspace of the Rabi-Stark model,the dressed states and then the effective Hamiltonian of the system are given.Due to the coupling of the mechanical oscillator and the atom-cavity system,if the initial state of the atom-cavity system is one of the dressed states,the mechanical oscillator will evolve into a corresponding coherent state.Thus,if the initial state of the atom-cavity system is a superposition of two dressed states,a coherent state superposition of the mechanical oscillator can be generated.The quantum coherence and their distinguishable properties of the two coherent states are exhibited by Wigner distribution.We show that the Stark term can enhance significantly the feasibility and quantum coherence of the generated macroscopic quantum superposition state of the oscillator.展开更多
It is well known that the macroscopic Maxwell’s equations can be obtained from the corresponding microscopic or atomic equations by a proper averaging process. The purpose of this paper is to present the macroscopic ...It is well known that the macroscopic Maxwell’s equations can be obtained from the corresponding microscopic or atomic equations by a proper averaging process. The purpose of this paper is to present the macroscopic Maxwell’s equations which are valid in all regions of space, including an interface between two different media; and the boundary conditions can naturally emerge from the macroscopic equations as an effect of average of the microscopic Maxwell’s equations. In addition, the application of the unit step functions and the Dirac delta function to our discussion not only permits great mathematical simplicity but also gives rise to convenient physical concepts for the description and representation of the actual fields in the vicinity of the interface.展开更多
70-30 brass is rolled with 90% reduction by cross shear rolling in single direction with speed ra- tio 1.39.The sheet is divided into five layers along rolling plane normal to measure macroscopic statis- tical unsymme...70-30 brass is rolled with 90% reduction by cross shear rolling in single direction with speed ra- tio 1.39.The sheet is divided into five layers along rolling plane normal to measure macroscopic statis- tical unsymmetric textures in every layer are des- cribed and analysed by means of three dimensional orientation distribution function.The results indi- cate that the main textures in every layer of brass rolled by cross shear rolling in single direction are the same as the main textures of brass rolled by conventional rolling.But the intensities,peak posi- tions and scatters of every texture component in {110}<112>are different,namely,there is a macroscopic statistical unsymmetry.It is found that the textures in every layer of brass rolled by cross shear rolling in single direction can be considered as the textures of brass rolled by common rolling in single direction at identical shear forces,the macroscopic statistical unsymmetry depends on the shear forces which are exerted on the layer.展开更多
Effective transportation systems lead to the efficient movement of goods and people, which significantly contribute to the quality of life in every society. In the heart of every economic and social development, there...Effective transportation systems lead to the efficient movement of goods and people, which significantly contribute to the quality of life in every society. In the heart of every economic and social development, there is always a transportation system. Mathematically the problem of modeling vehicle traffic flow can be solved at two main observation scales: The microscopic and the macroscopic levels. In the microscopic level, every vehicle is considered individually, and therefore, for every vehicle, we have an equation that is usually an ordinary differential equation (ODE). At a macroscopic level, we use from the dynamics models, where we have a system of partial differential equation, which involves variables such as density, speed, and flow rate of traffic stream with respect to time and space. Therefore, considering above content, this study has tried to compare solution of equation of macroscopic flow considering linear form (speed-density) and applying boundary condition that resulting to form solved is non-linear one-order partial differential equation (sharpy method) with non-linear assuming (speed and density) and consequently homographic nonlinear relation (speed-density). The recent case clearly gives more significant speeds than linear case of speed and density that can be a good scientific basis. In terms of safety for accidents and traffic signal, just as a reminder, but it is resulted of the reality that generally solutions of partial differential equations can have different forms. Therefore, the solution of partial differential equation (macroscopic flow) can have different answers and solutions so that all of these solutions apply in PDE (equation of macroscopic flow). Thus, under this condition, we can have solution of linear equation similar to greenberg or greenshield & android that are explained in logarithm and exponential function, but this article is based mostly on nonlinear solution of macroscopic equation, provided that existing nonlinear relationship between speed and density (homogra展开更多
文摘We propose an efficient scheme to generate a macroscopical quantum superposition state with a cavity optomechanical system,which is composed of a quantum Rabi-Stark model coupling to a mechanical oscillator.In a low-energy subspace of the Rabi-Stark model,the dressed states and then the effective Hamiltonian of the system are given.Due to the coupling of the mechanical oscillator and the atom-cavity system,if the initial state of the atom-cavity system is one of the dressed states,the mechanical oscillator will evolve into a corresponding coherent state.Thus,if the initial state of the atom-cavity system is a superposition of two dressed states,a coherent state superposition of the mechanical oscillator can be generated.The quantum coherence and their distinguishable properties of the two coherent states are exhibited by Wigner distribution.We show that the Stark term can enhance significantly the feasibility and quantum coherence of the generated macroscopic quantum superposition state of the oscillator.
文摘It is well known that the macroscopic Maxwell’s equations can be obtained from the corresponding microscopic or atomic equations by a proper averaging process. The purpose of this paper is to present the macroscopic Maxwell’s equations which are valid in all regions of space, including an interface between two different media; and the boundary conditions can naturally emerge from the macroscopic equations as an effect of average of the microscopic Maxwell’s equations. In addition, the application of the unit step functions and the Dirac delta function to our discussion not only permits great mathematical simplicity but also gives rise to convenient physical concepts for the description and representation of the actual fields in the vicinity of the interface.
文摘70-30 brass is rolled with 90% reduction by cross shear rolling in single direction with speed ra- tio 1.39.The sheet is divided into five layers along rolling plane normal to measure macroscopic statis- tical unsymmetric textures in every layer are des- cribed and analysed by means of three dimensional orientation distribution function.The results indi- cate that the main textures in every layer of brass rolled by cross shear rolling in single direction are the same as the main textures of brass rolled by conventional rolling.But the intensities,peak posi- tions and scatters of every texture component in {110}<112>are different,namely,there is a macroscopic statistical unsymmetry.It is found that the textures in every layer of brass rolled by cross shear rolling in single direction can be considered as the textures of brass rolled by common rolling in single direction at identical shear forces,the macroscopic statistical unsymmetry depends on the shear forces which are exerted on the layer.
文摘Effective transportation systems lead to the efficient movement of goods and people, which significantly contribute to the quality of life in every society. In the heart of every economic and social development, there is always a transportation system. Mathematically the problem of modeling vehicle traffic flow can be solved at two main observation scales: The microscopic and the macroscopic levels. In the microscopic level, every vehicle is considered individually, and therefore, for every vehicle, we have an equation that is usually an ordinary differential equation (ODE). At a macroscopic level, we use from the dynamics models, where we have a system of partial differential equation, which involves variables such as density, speed, and flow rate of traffic stream with respect to time and space. Therefore, considering above content, this study has tried to compare solution of equation of macroscopic flow considering linear form (speed-density) and applying boundary condition that resulting to form solved is non-linear one-order partial differential equation (sharpy method) with non-linear assuming (speed and density) and consequently homographic nonlinear relation (speed-density). The recent case clearly gives more significant speeds than linear case of speed and density that can be a good scientific basis. In terms of safety for accidents and traffic signal, just as a reminder, but it is resulted of the reality that generally solutions of partial differential equations can have different forms. Therefore, the solution of partial differential equation (macroscopic flow) can have different answers and solutions so that all of these solutions apply in PDE (equation of macroscopic flow). Thus, under this condition, we can have solution of linear equation similar to greenberg or greenshield & android that are explained in logarithm and exponential function, but this article is based mostly on nonlinear solution of macroscopic equation, provided that existing nonlinear relationship between speed and density (homogra
