Berlin 2014 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 37: Quantum information: Concepts and methods I

Q 37.8: Talk

Thursday, March 20, 2014, 12:15–12:30, Kinosaal

Negativity as a counter of entangled dimensions — •Christopher Eltschka¹ and Jens Siewert^2,3 — ¹Institut für Theoretische Physik, Universität Regensburg, Regensburg, Germany — ²Departamento de Química Física, Universidad del País Vasco UPV/EHU, Bilbao, Spain — ³IKERBASQUE, Basque Foundation for Science, E-48011 Bilbao, Spain

Among all entanglement measures negativity arguably is the best known and most popular tool to quantify bipartite quantum correlations. It is easily computed for arbitrary states, including mixed states, of a composite system and can therefore be applied to discuss entanglement in an ample variety of situations. We show that the negativity can be viewed as an estimator of the number of degrees of freedom in which two subsystems are entangled. As it is possible to give lower bounds for the negativity even in a device-independent setting, it is the appropriate quantity to certify quantumness of both parties in a bipartite system and to determine the minimum number of dimensions that contribute to the quantum correlations. Unlike other methods to certify the dimension of a system, it does not need an independent upper bound to the number of dimensions in order to certify quatumness.