Application Of Bell Inequality And Nonlinear Bell-like Inequality In Quantum Information

Quantum nonlocality,as a widely used quantum resource,plays an important role in quantum information processing,quantum cryptography,quantum computing and so on.Bell's inequality,as a criterion of nonlocality,has also aroused great interest.This paper first introduces the historical background and research significance of nonlocality and Bell's inequality,and reviews the important theoretical and experimental achievements of quantum nonlocality and Bell's inequality in the past decades.After introducing the basic knowledge of quantum information and optical experimental platform,the principle of the common entanglement light source preparation--the spontaneous parametric down conversion process is described in this paper,and on this basis,the preparation of two-photon entanglement source is realized by using nonlinear crystal,and the maximum fidelity of the source can reach 99.04%.With the development of quantum mechanics,many forms and generalizations of Bell-like inequalities have appeared.Compared with the linear Bell inequality,the nonlinear Bell inequality provides a new method for discriminating quantum correlation.It is of great practical significance to study the properties of entangled states by using the nonlinear Bell inequality.Considering that entangled states with noise parameters can simulate the actual quantum communication process,numerical optimization is performed to find the optimal measurement operator for the maximal violation of nonlinear Bell inequality,and the influence of noise parameters is studied on the violation of the nonlinear Bell inequality.The results show that the entangled states with noise can also violate the nonlinear Bell inequality under certain conditions,and the more the number of measurements,the more demanding the entangled states are.This paper introduces a scheme to estimate the quantum random access code by using the computational tool based on the input and output probability distribution set,and finally realize the quantum randomness authentication.Compared with the similar schemes,the scheme reduces the requirement of state preparation..