Description

2009/10/06,  Bernd Oliver Viehmann (U. of Regensburg & UPV/EHU)

Place: Sala de Seminarios del Departamento de Física Teórica e Historia de la Ciencia
Time: 12h.
Title: Theory of multipartite entanglement in terms of the tangle measures

Abstract
Classification and quantification of multipartite entanglement can be tackled by means of certain locally SL-invariant polynomials in the coefficients of quantum states - the tangle measures. The entanglement of two- and three-qubit systems as measured by these quantities may be already considered as thoroughly understood. However, the major
challenges in this context are, first, the construction and interpretation of the corresponding polynomial invariants for more general Hilbert spaces, and, second, the explicit evaluation of the tangle measures for mixed states.

This talk tries to shed some light on both issues: The relation of polynomial invariants of four-qubit states and the so-called SLOCC classification of entanglement will be investigated. Furthermore, a theorem about the 1-tangle of rank two states will be presented.