title: Evaluating convex roof entanglement measures.
abstract: We show a powerful method to compute entanglement measures based on convex roof constructions. In particular, our method is applicable to measures that, for pure states, can be written as low order polynomials of operator expectation values. We show how to compute the linear entropy of entanglement, the linear entanglement of assistance, and a bound on the dimension of the entanglement for bipartite systems. We discuss how to obtain the convex roof of the three-tangle for three-qubit states. We also show how to calculate the linear entropy of entanglement and the quantum Fisher information based on partial information or device independent information. We demonstrate the usefulness of our method by concrete examples.
authors.affiliation: Department of Theoretical Physics, University of the Basque Country UPV/EHU, E-48080 Bilbao, Spain.|IKERBASQUE, Basque Foundation for Science, E-48011 Bilbao, Spain.|Wigner Research Centre for Physics, Hungarian Academy of Sciences, H-1525 Budapest, Hungary.
authors.forename: Géza
authors.initials: G
authors.lastname: Tóth
authors.affiliation: Naturwissenschaftlich-Technische Fakultät, Universität Siegen, Walter-Flex-Straße 3, 57068 Siegen, Germany.
authors.forename: Tobias
authors.initials: T
authors.lastname: Moroder
authors.affiliation: Naturwissenschaftlich-Technische Fakultät, Universität Siegen, Walter-Flex-Straße 3, 57068 Siegen, Germany.
authors.forename: Otfried
authors.initials: O
authors.lastname: Gühne