Four-mode Optomechanics,intra-cavity Tunneling Induced Transparency And Thermal Light Cross-kerr Effect

Although the quantum correlations boost various innovative applications of quantum states,it is very sensitive to any noise from environment.In usual protocols in quantum information processing and quantum technology,it is necessary for preparation of quantum state to be isolated from environmental noises.Although this endeavor has created many techniques to precisely prepare and control the quantum state of single particles or few particles,it is still difficult to deal with complex quantum systems of multi-particles.Beyond the major schemes,two unusal approaches has attracted much attention to prepare the quantum state in quantum information processing in the past decade.One is involved in reservoir engineering,and the other is about dynamics of weak interaction.Reservoir engineering regards the environments of the quantum system as resources to create a stationary state.Althrough the noise still takes effect,pure entanglement state or states with hight quantum correlations can be obtained with special choosen dissipation channel.In this field,many schemes and basic mechanisms have been fully discussed and experimentally verified.For weak interaction,the interaction time is very short,and the interaction strength is very weak,which makes quantum evolution changed very small.Thus dissipation in this weak process can be also omitted and high pure quantum state can be prepared.Recently,the idea combining the weak interaction and postselection attracts much attenstion.This is usually called postselection weak measurement.This scheme can be taken as implement of the standerd measurement in postselection of the quantum state.However,up to now,this perspective has beyond a measurement scheme to play an important role in preparation of a quantum state and to do precisemetrology.Quantum optomechanics has been a hot topic in experimental quantum optics,which stimulates many creative theoretical researches.For the mechanical oscillator in a macroscopic object,the quantum correlations introduced by it is vital to our understanding on the quantum fundamental problems.A major problem in this field is how to effectively create entanglement or even strong entanglement.Based on the existing work,we firstly use the idea of dissipative engineering to dicuss entanglement in a four-mode optomechanical system at room temperature.In the past,it is widely accepted that the entanglement between two boson modes is below 0.7,and there is none entanglement at room temperature.However,Yingdan Wang et al provided new method to generate strong entanglement.They care about situation at zero degree Kelvin but don’t discuss that at room temperature.We find that prominent entanglement can also exist at room-temperature,which can not be found before.Meanwhile this system is also a typical example without subspaces of quantummechanics.In the following,we discuss with issues of the conherent state coversion between two fields with different frequencies based on the same four-mode setup.Converting informations between different fields is a basic problem in quantum networks.In the existing scheme,if high conversion efficiency is expected,the driving strengths between two cavity modes and the two driving modes must be large enough and the losses of the two target cavities are nearly the same.However,on one hand,too large intensities of driving lights are against controlling and thus easily induce the mechanical oscillator hot,and degrade the conversion effiency.On the other hand,the qualitiy designing for the two cavites needs to be high.We proposed and analysised the idea of driving the cavity mode at blue-detuned sideband for the first time.We demonstrated that the optomechanical cooperativity can be greatly decreased and losses of the two target modes can be different.We revealed a simple mode-removing method,which can be very useful for other quantum controlling problems.In my work using semiconductor microcavity,cavity can be used to reduce thedissipation of the quantum system,and can also greatly increase the coupling strength between light fields and the quantum system.A common dissipation channel is utilized to create tunnelling induced transperancy and to interfere two adjacent quantum states,inducing transperancy.In this thesis,two quantum devices based on this microcavity system is discussed at the intermediate infrared region for lights.One can be used to postpone the propagating time,and another can used to control two color lights simultaneously.From its apperence,postselection weak measurement has caused a lot of controvers.Using this idea to amplify the single-photon cross-Kerr nonlinearity,its unexpected amplification effect has been confirmed by many experiments.Different form much existing work,that only coherent light is used to do as the probe,we study the single-photon cross-Kerr effect using a thermal light as a meter.We find the results using thermal light cross-Kerr effect different from that induced by the coherent light.We disuss the strong effect induced by the thermal meter itself,which is beyond the traditional opinions.We find the weak value is not useful to explain the strong effects.Furthermore we present the postseletion induced reduction and large probability amplification.Thermal light cross-Kerr effect also reveals that the imaginary amplification is a pure classical effect,and we give the general dynamics for it based on the balanced weak measurement.