Theoretical Research Of Cross-energy Quantum Entanglement In Hybrid Quantum Systems

In recent decades,quantum information science has rapidly developed,in which quantum entanglement and other special quantum resources only exist in the quantum world play an important role.However,the decoherence caused by the inevitable interaction between the quantum system and the environment has always been an important obstacle that limits the development of quantum entanglement and its corresponding quan-tum technology.Therefore,realizing steady-state quantum entanglement in appropriate quantum systems is a significant research direction for the further development of quantum information science.With the concept of quantum network and quantum internet emerges,it is no longer enough to produce quantum entanglement in a single quantum system to keep up with the demand of quantum technology.Realizing cross-energy quantum entanglement in hybrid quantum systems is the future trend.The so-called hybrid quantum system is a mixed system that consists of two or more single quantum systems.Due to the effective coupling between the subsystems,the hybrid quantum system can combine the advantages of its subsystems,so as to complement each other and more effectively satisfy the demands of the development of quantum technology.The cross-energy quantum entanglement refers to the establishment of quantum entanglement between physical carriers in different energy domains,such as quantum entanglement between microwave photons of different frequencies,quantum entanglement between optical frequency pho-tons and microwave photons,etc.,which is of vital importance of the quantum network or the quantum internet.Based on this,this thesis mainly studies the theoretical schemes to generate steady-state quantum entanglement in hybrid quantum systems.The main content includes the following parts:1.Based on the radiation pressure between photon and microwave photon and the mechanical resonator,this paper proposes a theoretical scheme of continuous-variable quantum entanglement between microwave modes of different frequencies and between optical and microwave modes in a hybrid electro-optomechanical system.Under the experimentally feasible parameter regime,the influence of relevant important parameters on quantum entanglement between different energy domain is studied;2.On the basis of part 1,this paper analyzes the pairwise continuous-variable quan-tum entanglement in the hybrid electro-optomechanical system.Under the experimentally feasible parameter regime,referring to the discrete-variable pairwise quantum entanglement characteristics,the influence of each important physical parameter on continuous-variables pairwise quantum entanglement is studied;3.In the novel hybrid magnon-based quantum system,based on the optomagnonic coupling generated by the magnon-based Brillouin scattering and the electromagnonic coupling generated by the dipole-dipole action,this paper proposes a scheme to generate magnon-mediated optical-microwave steady-state entanglement.The same as the previous two works,this part uses logarithmic negativity as the measure of quantum entanglement and gives a detailed theoretical derivation.While analyzing the influence of various important physical parameters on the steady-state entanglement between light and microwave,we also give several schemes to improve the proposed optical-microwave entanglement;4.This part discusses the application of optical-microwave entanglement in hybrid magnon-based quantum systems-microwave quantum illumination.Assuming that using equal transmitted energy to detect the unknown targets,compared with the microwave classical illumination and quantum illumination based on the hybrid electro-optomechanical system,our scheme exhibits orders of magnitude lower detecting error probability.