title: Maximal violation of Bell's inequalities for continuous variable systems.
abstract: We generalize Bell's inequalities to biparty systems with continuous quantum variables. This is achieved by introducing the Bell operator in perfect analogy to the usual spin- 1/2 systems. It is then demonstrated that two-mode squeezed vacuum states display quantum nonlocality by using the generalized Bell operator. In particular, the original Einstein-Podolsky-Rosen states, which are the limiting case of the two-mode squeezed vacuum states, can maximally violate Bell's inequality due to Clauser, Horne, Shimony, and Holt. The experimental aspect of our scheme is briefly considered.
authors.affiliation: Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230027, People's Republic of China.
authors.forename: Zeng-Bing
authors.initials: ZB
authors.lastname: Chen
authors.forename: Jian-Wei
authors.initials: JW
authors.lastname: Pan
authors.forename: Guang
authors.initials: G
authors.lastname: Hou
authors.forename: Yong-De
authors.initials: YD
authors.lastname: Zhang