Investigation Of Properties Of Quantum State Based On Quantum Scissors

With the development of quantum information technology,people have higher requirements for the efficiency and accuracy of information transmission.As the basis of quantum information processing,the preparation of light field quantum state is particularly important.However,as the information carrier,the classical light field cannot meet the existing development needs.When the non-classical quantum state as the input state of the interferometer,the standard quantum limit can be broken.Therefore,it is very important to prepare non classical quantum states.In this paper,we propose several new preparation methods of non-Gaussian states,and analyze the properties of the prepared non-Gaussian states by using Wigner function and antibunching effect,et al.The details are as follows:First,we propose a scheme for preparing non classical state by introduce the local squeezing operation into the quantum scissor device.By selecting the coherent state as the input state,we can truncate the input coherent state into the superposition form of vacuum,single photon and two-photon.The results show that the increase of the local squeezing parameter not only makes the average photon number increase obviously,but also increases the volume of the negative part of the Wigner function.In addition,the increase of the amplitude of the coherent state can increase the average photon number,but it will also lead to the decrease of the volume of the negative part of the Wigner function.These results show that compared with the case without local squeezing,the quantum scissor device with local squeezing has a significant advantage in the preparation of strongly nonclassical non-Gaussian states.Second,we propose a new scheme to generate non-Gaussian entangled states by two catalytic quantum shears(CQS)acting on two mode squeezed vacuum states(TMSVS).The output state is truncated into the superposition form of single photon and two-photon.The results show that when the transmission coefficient and initial compression of the beam splitter are appropriate,we can not only greatly improve the success probability,but also improve the fidelity between the input state and the output state.Through Wigner function and EPR correlation,we analyze and optimize the nonclassical properties of the generated state,and we find that,in the case of small initial squeezing,the entanglement of the generated state is obviously enhanced in the region of high transmission and low transmission,respectively.These results may have potential applications in future quantum communication.Finally,we still propose a new method to prepare the nonclassical states.For different input states,such coherent state,single-mode squeezed vacuum state,and thermal state,the different non classical states are prepared after the displacementbased single-side quantum scissor,which is a superposition of zero-photon state and single photon state.The nonclassical properties of the output state are analyzed by Wigner function,SRN and APN.The results show that the signal-to-noise ratio can be improved by embedding large local shift operation in the system.The volume of the negative part of Wigner function increases with the increase of displacement coherent amplitude,which indicates that the generated state is highly nonclassical.