论文部分内容阅读
Two orthonormal bases of a d-dimensional Hilbert space are called mutually unbiased (MU) if the d^2 transition probabilities from any state of one basis to any state of the other basis coincide (cf.[1] for a recent review).This property expresses the notion of complementarity for discrete variables,by analogy with the eigenbases of the canonical position and momentum operators of a quantum particle.It is always possible to construct three MU bases in the state space of a finite quantum system with d orthogonal states.If the dimension d is a prime number or a prime power,even (d+1) pairwise MU bases can be found.Pairs as well as larger sets of MU bases have a number of useful applications.