2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/146451We show that weighted unitary 2-designs define optimal measurements on the system-ancilla output state for ancilla-assisted process tomography of unital quantum channels. Examples include complete sets of mutually unbiased unitary-operator bases. Each of these specifies a minimal series of optimal orthogonal measurements. General quantum channels are also considered.28 pagesQuantum Physicstext