A class of nonlinear problems with real parameters is defined. Generally, in this class of problems, when the parametric values are very large, the problems become ill-posed and numerical difficulties are encountered ...A class of nonlinear problems with real parameters is defined. Generally, in this class of problems, when the parametric values are very large, the problems become ill-posed and numerical difficulties are encountered when trying to solve these problems. In this paper, the nonlinear problems are reformulated to overcome the numerical difficulties associated with large parametric values. A novel iterative algorithm, which is suitable for large scale problems and can be easily parallelized, is proposed to solve the reformulated problems. Numerical tests indicate that the proposed algorithm gives stable solutions. Convergence properties of the proposed algorithm are investigated. In the limiting case, when the corresponding constraint is exactly satisfied, the proposed method is equivalent to the standard augmented Lagrangian method.展开更多
Cavity magnomechanics has recently become a new platform for studying macroscopic quantum phenomena.The magnetostriction induced vibration mode of a large-size ferromagnet or ferrimagnet reaching its ground state repr...Cavity magnomechanics has recently become a new platform for studying macroscopic quantum phenomena.The magnetostriction induced vibration mode of a large-size ferromagnet or ferrimagnet reaching its ground state represents a genuine macroscopic quantum state.Here we study the ground-state cooling of the mechanical vibration mode in a cavity magnomechanical system,and focus on the role of magnon squeezing in improving the cooling efficiency.The magnon squeezing is obtained by exploiting the magnon self-Kerr nonlinearity.We find that the magnon squeezing can significantly and even completely suppress the magnomechanical Stokes scattering.It thus becomes particularly useful in realizing ground-state cooling in the unresolved-sideband regime,where the conventional sideband cooling protocols become inefficient.We also find that the coupling to the microwave cavity plays only an adverse effect in mechanical cooling.This makes essentially the two-mode magnomechanical system(without involving the microwave cavity)a preferred system for cooling the mechanical motion,in which the magnon mode is established by a uniform bias magnetic field and a microwave drive field.展开更多
文摘A class of nonlinear problems with real parameters is defined. Generally, in this class of problems, when the parametric values are very large, the problems become ill-posed and numerical difficulties are encountered when trying to solve these problems. In this paper, the nonlinear problems are reformulated to overcome the numerical difficulties associated with large parametric values. A novel iterative algorithm, which is suitable for large scale problems and can be easily parallelized, is proposed to solve the reformulated problems. Numerical tests indicate that the proposed algorithm gives stable solutions. Convergence properties of the proposed algorithm are investigated. In the limiting case, when the corresponding constraint is exactly satisfied, the proposed method is equivalent to the standard augmented Lagrangian method.
基金supported by Zhejiang Province Program for Science and Technology(2020C01019)the National Natural Science Foundation of China(U1801661,11874249,11934010,12174329).
文摘Cavity magnomechanics has recently become a new platform for studying macroscopic quantum phenomena.The magnetostriction induced vibration mode of a large-size ferromagnet or ferrimagnet reaching its ground state represents a genuine macroscopic quantum state.Here we study the ground-state cooling of the mechanical vibration mode in a cavity magnomechanical system,and focus on the role of magnon squeezing in improving the cooling efficiency.The magnon squeezing is obtained by exploiting the magnon self-Kerr nonlinearity.We find that the magnon squeezing can significantly and even completely suppress the magnomechanical Stokes scattering.It thus becomes particularly useful in realizing ground-state cooling in the unresolved-sideband regime,where the conventional sideband cooling protocols become inefficient.We also find that the coupling to the microwave cavity plays only an adverse effect in mechanical cooling.This makes essentially the two-mode magnomechanical system(without involving the microwave cavity)a preferred system for cooling the mechanical motion,in which the magnon mode is established by a uniform bias magnetic field and a microwave drive field.
