2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/145390We present a new method for quantum process tomography. The method enables us to efficiently estimate, with fixed precision, any of the parameters characterizing a quantum channel. It is selective since one can choose to estimate the value of any specific set of matrix elements of the super-operator describing the channel. Also, we show how to efficiently estimate all the average survival probabilities associated with the channel (i.e., all the diagonal elements of its $χ$--matrix.4 pagesQuantum Physicstext