Precessing ball solitons (PBS) in a ferromagnet during the first order phase transition induced by a magnetic field directed along the axis of anisotropy, while the additional action of high-frequency field perpendicu...Precessing ball solitons (PBS) in a ferromagnet during the first order phase transition induced by a magnetic field directed along the axis of anisotropy, while the additional action of high-frequency field perpendicular to the main magnetic field, are analyzed. It is shown that the spatial motion of solitons, associated with thermal fluctuations in the crystal, does not destroy the equilibrium of self-organized PBS.展开更多
In this paper,symplectic schemes and symmetric schemes are presented to simulate Nonlinear Schrodinger Equation(NLSE)in case of dark soliton motion.Firstly,by Ablowitz–Ladik model(A–L model),the NLSE is discretized...In this paper,symplectic schemes and symmetric schemes are presented to simulate Nonlinear Schrodinger Equation(NLSE)in case of dark soliton motion.Firstly,by Ablowitz–Ladik model(A–L model),the NLSE is discretized into a non-canonical Hamiltonian system.Then,different kinds of coordinate transformations can be used to standardize the non-canonical Hamiltonian system.Therefore,the symplectic schemes and symmetric schemes can be employed to simulate the solitons motion and test the preservation of the invariants of the A–L model and the conserved quantities approximations of the original NLSE.The numerical experiments show that symplectic schemes and symmetric schemes have similar simulation effect,and own significant superiority over non-symplectic and non-symmetric schemes in long-term tracking the motion of solitons,preserving the invariants and the approximations of conserved quantities.Moreover,it is obvious that coordinate transformations with more symmetry have a better simulation effect.展开更多
Using a nonadiabatic evolution method, we investigate the spin-flip process of polaron in polymers with a magnetic impurity. Our results show that when the spin orientation of this impurity is fixed to be perpendicula...Using a nonadiabatic evolution method, we investigate the spin-flip process of polaron in polymers with a magnetic impurity. Our results show that when the spin orientation of this impurity is fixed to be perpendicular to the spin of polaron （θ = π/2）, the magnetic impurity causes a spin-flip process. The probability of the spin-flip increases with the increase of exchange integral J up to about 0.35 eV and then decreases with the increase of J. In the case J is fixed while the spin orientation is adjustable, we find the probability of the spin-flip varies with the impurity orientation and reaches a maximum value at θ=π/2.展开更多
Using a nonadiabatic evolution method, we investigate the spin filter effect in organic polymers in the presence of a local magnetic field. Through a spin-dependent magnetic field, polarons （charge carrier） with dif...Using a nonadiabatic evolution method, we investigate the spin filter effect in organic polymers in the presence of a local magnetic field. Through a spin-dependent magnetic field, polarons （charge carrier） with different spins will feel repulsive or attractive force determined by their spins. Our simulations show that in a single-site magnetic field （affecting electrons at a single site）, for example V150 = 0.35 eV, or V150 = 0.45 eV, a spin-up polaron accelerated to saturated velocity by an electric field can pass through the field while the spin-down polaron is trapped. When the local field extends over several sites （Vn～ exp[-（n - nc）2/nw^2]）, similar behaviour is also found. Simultaneously we find that it is more likely to realize the spin filter effect in a comparatively large field since the polaron which feels attractive force is easily trapped by a local magnetic field.展开更多
A 2-D KdV equation is derived under condition of arbitrary continuous density profiles. A non-fission version of initial internal solitary waves propagating onto the continental shelf is studied by means of the 2-D Kd...A 2-D KdV equation is derived under condition of arbitrary continuous density profiles. A non-fission version of initial internal solitary waves propagating onto the continental shelf is studied by means of the 2-D KdV equation. Under non-Bohr and Sommerfeld's condition, numerical calculations are carried out based on the KdV equation. The result shows that the initial internal solitary waves in deep ocean break down into internal undular bores on the continental shelf. And the bores have a like-soliton leading fronts and undular trails.展开更多
文摘Precessing ball solitons (PBS) in a ferromagnet during the first order phase transition induced by a magnetic field directed along the axis of anisotropy, while the additional action of high-frequency field perpendicular to the main magnetic field, are analyzed. It is shown that the spatial motion of solitons, associated with thermal fluctuations in the crystal, does not destroy the equilibrium of self-organized PBS.
基金This work was supported by the Fundamental Research Funds for the Central Universities(Nos.2018ZY14,2019ZY20 and 2015ZCQ-LY-01)Beijing Higher Education Young Elite Teacher Project(YETP0769)the National Natural Science Foundation of China(Grant Nos.61571002,61179034 and 61370193).
文摘In this paper,symplectic schemes and symmetric schemes are presented to simulate Nonlinear Schrodinger Equation(NLSE)in case of dark soliton motion.Firstly,by Ablowitz–Ladik model(A–L model),the NLSE is discretized into a non-canonical Hamiltonian system.Then,different kinds of coordinate transformations can be used to standardize the non-canonical Hamiltonian system.Therefore,the symplectic schemes and symmetric schemes can be employed to simulate the solitons motion and test the preservation of the invariants of the A–L model and the conserved quantities approximations of the original NLSE.The numerical experiments show that symplectic schemes and symmetric schemes have similar simulation effect,and own significant superiority over non-symplectic and non-symmetric schemes in long-term tracking the motion of solitons,preserving the invariants and the approximations of conserved quantities.Moreover,it is obvious that coordinate transformations with more symmetry have a better simulation effect.
基金Supported by National Natural Science Foundation of China under Grant Nos 10674026 and 10321003, and the EC Project of SPIN （NMP3-CT-2006-033370）.
文摘Using a nonadiabatic evolution method, we investigate the spin-flip process of polaron in polymers with a magnetic impurity. Our results show that when the spin orientation of this impurity is fixed to be perpendicular to the spin of polaron （θ = π/2）, the magnetic impurity causes a spin-flip process. The probability of the spin-flip increases with the increase of exchange integral J up to about 0.35 eV and then decreases with the increase of J. In the case J is fixed while the spin orientation is adjustable, we find the probability of the spin-flip varies with the impurity orientation and reaches a maximum value at θ=π/2.
基金Supported by the National Natural Science Foundation of China under Grant Nos 90403110, 10374017, and 10321003.
文摘Using a nonadiabatic evolution method, we investigate the spin filter effect in organic polymers in the presence of a local magnetic field. Through a spin-dependent magnetic field, polarons （charge carrier） with different spins will feel repulsive or attractive force determined by their spins. Our simulations show that in a single-site magnetic field （affecting electrons at a single site）, for example V150 = 0.35 eV, or V150 = 0.45 eV, a spin-up polaron accelerated to saturated velocity by an electric field can pass through the field while the spin-down polaron is trapped. When the local field extends over several sites （Vn～ exp[-（n - nc）2/nw^2]）, similar behaviour is also found. Simultaneously we find that it is more likely to realize the spin filter effect in a comparatively large field since the polaron which feels attractive force is easily trapped by a local magnetic field.
文摘A 2-D KdV equation is derived under condition of arbitrary continuous density profiles. A non-fission version of initial internal solitary waves propagating onto the continental shelf is studied by means of the 2-D KdV equation. Under non-Bohr and Sommerfeld's condition, numerical calculations are carried out based on the KdV equation. The result shows that the initial internal solitary waves in deep ocean break down into internal undular bores on the continental shelf. And the bores have a like-soliton leading fronts and undular trails.
