Research On Blockade Effect Based On Radiation Pressure Interaction

As a non-classical light source,single-photon source plays an extensive and vital role in quantum communication,quantum simulation,quantum sensing,quantum precision measurement,etc.At present,the methods to realize single-photon source mainly include laser attenuation method and photon blockade.Photon blockade means that the first photon excited in the system will prevent the excitation of the second photon under the driving of classical light,which can reduce the probability of multiphoton in the cavity and the probability of multi-photon in the output field.In terms of mechanism,photon blockade can be divided into conventional photon blockade and unconventional photon blockade.Conventional photon blockade is due to the nonlinear effect that breaks the anharmonic of the energy level and makes 0 and 2 non-resonant,while unconventional photon blockade is due to the destructive interference between different channels of two-photon state that reduces the probability of two-photon generation.Like photon blockade,phonon blockade has the same mechanism.In this paper,we propose two methods to enhance the photon and phonon blockade effects,respectively.First,based on the optomechanical system,the influence of dissipation on the photon blockade is discussed.It finds that the greater the dissipation,the worse the blockade effect.Then we propose a scheme based on coherent feedback to reduce the system dissipation,thus enhancing the photon blockade effect.In addition,the influence of coherent feedback on the photon induced tunneling and cat state preparation is also discussed.The results show that the reduction of dissipation enhances the three-photons tunneling,It is also beneficial to the preparation of twocomponent cat state.In addition,based on the quadratically coupled optomechanical system,we propose a scheme to improve the phonon blockade effect by using a mechanical parametric amplification device.This scheme combines the advantages of conventional phonon blockade and unconventional phonon blockade.It improves the phonon blockade effect and makes the time-delay second-order correlation function not oscillate,so the observation does not need high time resolution.Our research provides a new theoretical solution for exploring photon blockade and phonon blockade,which may reduce the difficulty of realizing photon blockade and phonon blockade in experiments.The research contents of this paper are as follows:1.The first chapter introduces the theoretical background,research content and significance of photon and phonon blockade.2.The second chapter introduces the theoretical knowledge used in this paper,which include the system and the computational simulation methods of blockade effect.3.In the third chapter,we study the realization of conventional photon blockade in the system based on optomechanical system,we discuss how to use the coherent feedback to enhance the photon blockade effect.In addition,we discuss the application of coherent feedback in Schrodinger cat state.4.In the fourth chapter,based on quadratically coupled optomechanical system,a two-phonon driver is added,the advantages of conventional phonon blockade and unconventional phonon blockade are combined to further improve the phonon blockade.5.The fifth chapter summarizes the photon and phonon blockade effects in the scheme and makes a prospect.