Non-locality Reconsidered

Tian-Hai Zeng

The interaction between two parts in a compound quantum system may be reconsidered more completely than before and some new understandings and conclusions different from current quantum mechanics are obtained, including the conservation law in the evolution in an isolated quantum system, new understandings of duality of particle and wave and the superposition principle of states, three laws corresponding to Newton's laws, new understandings of measurement and the uncertainty relation, arguments against the non-locality of any entangled state and a simple criterion of coherence which is obtained for the experimenter to examine the correctness of the non-locality. These may make quantum mechanics be easily understood intuitively and some strange properties will not appear.

Frank Verstraete, Norbert Schuch, J. I. Cirac

Effective superselection rules severely alter the possible operations that can be implemented on a distributed quantum system. Superselection rules appear in e.g. the context of experiments with entangled cold gases: in this case all local operations have to conserve the local particle number. These superselection rules enforces us to reconsider the notion of nonlocality, as the new constraint implies limitations on the local operations that can be implemented. This gives rise to a novel form of nonlocality, and it is possible to associate a new nonlocal resource to it. In this paper we characterize this new resource, quantify it and discuss some applications.

Peder Voetmann Christiansen

Akira Saitoh, Robabeh Rahimi, Mikio Nakahara

It is a popular idea that a multi-partite quantum system represented by a density matrix having no product eigenbasis possesses non-classical correlation. Supporting this idea, we define an entropic measure of non-classical correlation on the basis of the minimum uncertainty about a joint-system after we collect reports of particular local measurements. Numerical computation of this measure for several examples is performed.