ua nt - p h / 04 11 09 8 v 1 1 5 N ov 2 00 4 A class of 2 N × 2 N bound entangled states revealed by non - decomposable maps

ua nt - p h / 01 11 01 2 v 2 1 5 N ov 2 00 1 Measurements of semi - local and non - maximally entangled states

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 × 2dimensional bipartite system are measurable.

ar X iv : q ua nt - p h / 04 11 17 2 v 1 2 3 N ov 2 00 4 Information and Entropy in Quantum Theory

ua nt - p h / 01 11 01 2 v 1 1 N ov 2 00 1 Measurements of semi - local and non - maximally entangled states

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 an explicit construction, that all Hermitian observable of a 2 × 2-dimensional bipartite system are measurable.

ar X iv : q ua nt - p h / 06 11 14 4 v 1 1 4 N ov 2 00 6 Geometrical structure of entangled states and secant variety

We show that the secant variety of the Segre variety gives useful information about the geometrical structure of an arbitrary multipartite quantum system. In particular, we investigate the relation between arbitrary bipartite and three-partite entangled states and this secant variety. We also discuss the geometry of an arbitrary general multipartite state.

ua nt - p h / 00 11 09 6 v 1 2 3 N ov 2 00 0 su ( 2 ) and su ( 1 , 1 ) displaced number states and their nonclassical properties

We study su(2) and su(1,1) displaced number states. Those states are eigenstates of density-dependent interaction systems of quantized radiation field with classical current. Those states are intermediate states interpolating between number and displaced number states. Their photon number distribution, statistical and squeezing properties are studied in detail. It is show that these states exhi...