The Manipulation Of Photon Based On Cavity Quantum Electrodynamics System And Cavity Optomechanical System

It is well known that photons,as the carrier of the information,play an important role in quantum information processing and quantum communication.Some optical nonlinear behaviors such as photon blockade,optical bistability and optical multistability could enable photons to be controlled effectively in applications of optical quantum information processing,communication and the photon manipulation.In addition,quantum entanglement and quan-tum coherence are the important physical resources in quantum information processing,and it can be said that all quantum information processing tasks require quantum entanglement or quantum coherence.Therefore,seeking for a suitable quantum system as the“hardware”to perform these characteristics has become a crucial research topic.Compared to other systems,cavity quantum electrodynamics(cavity QED)system and cavity optomechanical system have distinct advantages in some aspects,which attract a lot of attention.This thesis is mainly focusing on two aspects:One is to find the relation between the photon statistics and quantum entanglement,quantum coherence in the cavity QED system;Another one is to study the effect of the atomic center-of-mass motion on the photon statistics and perfect photon absorption,optical bistability/multistability in a hybrid atom-optomechanical sys-tem.The thesis consists of seven chapters in which Chaps.3 to 6 covers the main research work performed during my doctoral study.In Chapter 1,we introduce the background of this thesis and the developments of the quantum information and quantum optics,and also present briefly the nonlinear optical effect and cavity QED system,cavity optomechanical system.In Chapter 2,we introduce the basic concepts and knowledge,including the quantum qubit,coherence function,quantum entanglement measure,quantum master equation,quan-tum Langevin equation and input-output relation.In Chapter 3,we design a cavity QED model with two atoms trapped in to demonstrate the connection between the steady-state photon statistics and the two-atom entanglement.The effects of photon bunching and anti-bunching correspond to the classical and quantum features of the electromagnetic field.No direct evidence suggests whether these effects can be potentially related to quantum entanglement.The atomic entanglement as an intriguing quantum feature perfectly correspond to not only the quantum feature of the electromagnetic field—the optimal photon antibunching,but also the classical feature—the optimal photon bunching.In addition,we also find that the maximal photon bunching point corresponds to the almost vanishing entanglement due to the dark-state process.We also investigate how the correspondence is affected by thermal noises and pure dephasing.In Chapter 4,we systematically study the system parameters' dependence on the photon statistics and atomic coherence by designing a weakly driven cavity QED system with a two-level atom trapped.Here instead of only illustrating the photon statistics,we use the analytical and numerical methods to show the interesting relation between the steady-state photon blockade and the atomic coherence.It is shown that the maximal atomic coherence presents a perfect correspondence with the optimal photon blockade.In Chapter 5,we study the effect of the atomic center-of-mass motion on the photon statistics.With the resonant interaction among atom,photon and phonon,it is shown that the bunching and anti-bunching of photons can occur with properly driving frequency.Our study provides an attempt to take advantage of the center of-mass motion.In Chapter 6,we propose a scheme to investigate the perfect photon absorption in a hybrid atom-optomechanical system under and beyond the low-excitation limit.We find that the perfect photon absorption is present in both cases and always accompanied by the optical bistability or multistability,and especially induces an additional perfect absorption point will be induced and optical nonlinearities enhanced once beyond the low-excitation limit.In addition,all the parameters employed in the numerical procedure are taken from the practical experiments,and the present scheme can be realized with the current experimental techniques.Finally,we present the conclusion and propose an outlook for the further work.