Measurements of semi-local and non-maximally entangled states

Abstract

Consistency with relativistic causality narrows down dramatically the class of measurable observables. We argue that by weakening the preparation role of ideal measurements, many of these observables become measurable. Particularly, we show by applying entanglement assisted remote operations, that all Hermitian observable of a $2\times2$-dimensional bipartite system are measurable.

13 pages, one figure, typo corrected in eq. 9, and tables on pages 10 and 11