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Seminários do grupo de Óptica e Informação Quântica

Data: Sexta-Feira 29/04/2016, Sala A5-01, 11 am.

Palestrante: Peter Alexander Bouvrie Morales (CBPF)

Título: Multipartite concurrence for identical-fermion systems

Abstract: The characterization of multipartite entanglement is tricky, but when the parts are fermions it might become even controversial; the elementary (antisymmetric) pure state of a quantum system composed by N identical fermions is a single Slater determinant, hence it formally looks entangled (in contrast, for example, with a separable pure state of distinguishable qubits). Nevertheless, there exists some extended consensus that a pure fermion state is separable if it is a single antisymmetric product state given by a single Slater determinant. Under this statement, we study the problem of detecting multipartite entanglement among indistinguishable fermionic particles. A multipartite concurrence for pure states of N identical fermions, each one having a d-dimensional single-particle Hilbert space, is introduced. Such an entanglement measure, in particular, is optimized for maximally entangled states of three identical fermions that play a role analogous to the usual (qubit) Greenberger-Horne-Zeilinger state. In addition, it is shown that the fermionic multipartite concurrence can be expressed as the mean value of an observable, provided two copies of the composite state are available