2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/102457The problem of estimating the spectrum of a density matrix is considered. Other problems, such as bipartite pure state entanglement, can be reduced to spectrum estimation. A local operations and classical communication (LOCC) measurement strategy is shown which is asymptotically optimal. This means that, for a very large number of copies, it becomes unnecessary to perform collective measurements which should be more difficult to implement in practice.12 pages, uses iopart.cls and iopart10.clo. Improved version. v3: Reference updated, added journal referenceQuantum Physicstext