2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/113230The experimental determination of entanglement is a major goal in the quantum information field. In general the knowledge of the state is required in order to quantify its entanglement. Here we express a lower bound to the robustness of entanglement of a state based only on the measurement of the energy observable and on the calculation of a separability energy. This allows the estimation of entanglement dismissing the knowledge of the state in question.3 pages, 1 figure. Comments welcome. V2: references updated. Accepted version by Applied Physics LettersQuantum PhysicsStrongly Correlated Electronstext