Theory of Packaged Entangled States

Representation of Entangled States

It is impossible to know the probability amplitudes of an unknown state, because if one could do so, one can clone the state. This means that identifying a pair of correlated qubits with the perfectly entangled state 1 2 (|00〉+ |11〉) is an idealization unless it is certified by tests on identically produced pairs from a coherent source. Questions related to the reference frame for measurement o...

Geometry of entangled states

Geometric properties of the set of quantum entangled states are investigated. We propose an explicit method to compute the dimension of local orbits for any mixed state of the general K3M problem and characterize the set of effectively different states ~which cannot be related by local transformations!. Thus, we generalize earlier results obtained for the simplest 232 system, which lead to a st...

Multipartite entangled coherent states

We propose a scheme for generating multipartite entangled coherent states via entanglement swapping, with an example of a physical realization in ion traps. Bipartite entanglement of these multipartite states is quantified by the concurrence. We also compute multipartite entanglement for certain systems. Finally we establish that these results for entanglement can be applied to more general mul...

Collective entangled dark states

Mixed maximally entangled states

We find that the mixed maximally entangled states exist and prove that the form of the mixed maximally entangled states is unique in terms of the entanglement of formation. Moreover, even if the entanglement is quantified by other entanglement measures, this conclusion is still proven right. This result is a supplementary to the generally accepted fact that all maximally entangled states are pu...