On the local unitary equivalence of states of multi-partite systems

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Authors	ZIMAN Mario STELMACHOVIC P. BŮŽEK Vladimír
Year of publication	2001
Type	Article in Periodical
Magazine / Source	FORTSCHRITTE DER PHYSIK-PROGRESS OF PHYSICS
MU Faculty or unit	Faculty of Informatics
Citation
Field	Informatics
Description	Two pure states of a multi-partite system are alway are related by a unitary transformation acting on the Hilbert space of the hole system. This transformation involves multi-partite transformations. On the other hand some quantum information protocols such as the quantum teleportation and quantum dense coding are based on equivalence of some classes of states of bi-partite systems under the action of local (one-particle) unitary operations. In this paper we adress the question: "Under what conditions are the two states states, Q and a, of a multi-partite system locally unitary equivalent?" We present a set of conditions which have to be satisfied in order that the two states are locally unitary equivalent. In addition, we study whether it is possible to prepare a state of a multi-qudit system. Which is devided into two parts A and B, by unitary operations acting only on the systems A and B, separately.
Related projects:	Informatics as the third methodology Non-sequential Models of Computing -- Quantum and Concurrent Distributed Models of Computing