2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/97401Quantum state tomography--the practice of estimating a quantum state by performing measurements on it--is useful in a variety of contexts. We introduce "gentle tomography" as a version of tomography that preserves the measured quantum data. As an application of gentle tomography, we describe a simple polynomial-time method for universal source coding.4 pages, revtex4Quantum Physicstext