Study On Magnon Blockade Based On A Parity-time-symmetric-like Cavity Magnomechanical System

In recent years,thanks to the rapid development of the micro-nano manufacturing industry,the magnomechanical system has become one of the best candidates for studying the quantum effects of matter and quantum information processing on a macro scale.The traditional cavity magnomechanical system is a special quantum system which is hybridized with a microwave cavity and a ferromagnetic yttrium iron garnet spheres.Compared with the traditional cavity optomechanical system,the unique high spin density and lower damping rate of the cavity magnomechanical system can not be achieved in most optomechanical systems,and the relevant physical characteristics of the magnon can be adjusted by applying a static magnon field,that is,the relevant application of the system can be realized by adjusting a single degree of freedom.In recent years,with the further development of cavity magnomechanical systems,it has become an important research topic to obtain high-efficiency and stable single magnon sources in quantum communication and other fields.Therefore,magnon blockade has become the primary problem in the cavity magnomechanical system,which can be realized by adjusting the external bias magnetic field.It is the characteristic that is dependent on the magnetic field that the cavity magnetomechanical system provides theoretical support for realizing the quantum manipulation of the single magnon energy level.In this thesis,the magnon blockade effect is studied in a parity-time(PT)-symmetric-like cavity magnetomechanical system,and the main contents are as follows:Based on the PT-symmetric-like three-mode cavity magnomechanical system,the magnon blockade effect including magnon-photon and magnon-phonon interactions is investigated.A theoretical scheme is proposed to adjust different system parameters to realize magnon blocking.Generally speaking,the PT-symmetric optomechanical system is a two-mode system,and what is considered here is a three-mode system composed of a microwave cavity mode,a magnon mode and a phonon mode.At the same time,the phase transition behavior is studied based on broken and unbroken P T-symmetric regions.By analytically solving the Schr?dinger equation and the numerical simulation master equation of the second-order correlation function respectively,the optimal detuning value of the ideal magnon blockade can be obtained.Particularly,the anharmonicity of the eigenenergy spectrum are also analyzed,and the optimal condition of the magnon blockade are studied.In addition,it is also find that the magnon blockade effect can be achieved by either adjusting the coupling strength or the nonlinear parameter.In order to further understand the phenomenon of magnon blockade,different blockade mechanisms are also discussed.The results indicate that one dip corresponds to the unconventional magnon blockade while two new dips to the conventional magnon blockade.The scheme provides a feasible method for realizing magnon blockade in the weak parameter regime,which greatly reducing the difficulty of the experiment,paving the way for realizing magnon blockade in the experiment,and providing a theoretical basis for realizing a single magnon source.