Research On Determination Methods Of Bell's Nonlocality

Bell nonlocality is one of the strongest quantum correlations in a compound quantum system and becomes an important resource of quantum information processing.In this paper,we study the determination methods of Bell nonlocality using some methods from operator theory and operator algebras.The thesis is divided into three chapters and its specific structures are as follows.In Chapter 1,we introduce some research background and current situation of the topic and list some basic concepts and existing results used in the paper.In Chapter 2,we study the Bell nonlocality of quantum state in two body system.Firstly,we prove some necessary conditions for bipartite state to be Bell local.Secondly,we obtain some sufficient conditions for Bell's nonlocality according to the necessary conditions for Bell's locality of bipartite state.Finally,by using this sufficient condition,we verify the Bell nonlocality of a 2-qubit entangled pure state by constructing a general observable measurement and obtain the maximum probability of success that the 2-qubit entangled pure state is a bipartite Bell nonlocal state.In Chapter 3,we generalize the results for two-body system to the multi body system.Firstly,we get some necessary conditions for multipartite state to be Bell local.Secondly,we get some sufficient conditions to distinguish Bell nonlocality of a multi-body quantum state according to the necessary conditions of Bell locality.Finally,by using this sufficient condition,we verify t he Bell nonlocality of an n-qubit entangled pure state by constructing general observables and obtain the maximum success probability of n-qubit entangled pure state being Bell nonlocal.