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Seminário do grupo de Óptica e Informação Quântica

Data: Sexta-Feira 01/06/2011 Sala A5-01, 11:00

Palestrante: Helena Braga (UFsCar)

Título: D-7 manifold for two qubits in compact Minkowski space

Resumo: The entanglement properties as well as the existing criteria such as the partial positive transposition and concurrence when described through an isomorphism of the density operator (for a two-qubit system) in a R³ space provides a quantitave physical understood of the fenomena, This understood became transparent by choosing a subset of X states according to elements of SU(2)⊗U(1)⊗SU(2) group algebra. This quantitative analysis consist of detemining invariant squared distances strongly based on positive partial transposition, in a very similar form as those written in the relativity space-time with a Minkowski metric, s²=t²-r². Similarly to Minkowski diagram it is also possible to divide the space through a conic shaped surface where inside there are separable like states and outside the entangled like ones. This method provides not just the determination of separability but also a measure of quantity of entanglement, and a symmetry based explanation for the existing criteria. In this work we show that the method of distances of entanglement can be aplied to other classes of the subalgebra of X states, in a more general way to any D-7 manifold class and not just the traditional X state.