Vidal Bonafont, GuifréTarrach, R., 1948-2009-10-062009-10-0619991050-2947https://hdl.handle.net/2445/9553In the quest to completely describe entanglement in the general case of a finite number of parties sharing a physical system of finite-dimensional Hilbert space an entanglement magnitude is introduced for its pure and mixed states: robustness. It corresponds to the minimal amount of mixing with locally prepared states which washes out all entanglement. It quantifies in a sense the endurance of entanglement against noise and jamming. Its properties are studied comprehensively. Analytical expressions for the robustness are given for pure states of two-party systems, and analytical bounds for mixed states of two-party systems. Specific results are obtained mainly for the qubit-qubit system (qubit denotes quantum bit). As by-products local pseudomixtures are generalized, a lower bound for the relative volume of separable states is deduced, and arguments for considering convexity a necessary condition of any entanglement measure are put forward.15 p.application/pdfeng(c) The American Physical Society, 1999Teoria quànticaTeoria de la informacióQuantum informationinfo:eu-repo/semantics/article146068info:eu-repo/semantics/openAccess