2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/92383In this paper we present a solution of the Einstein's boxes paradox by modern Quantum Mechanics in which a notion of density matrix is equivalent to a notion of a quantum state of a system. We use a secondary quantization formalism in the attempt to make a description particularly clear. The aim of this paper is to provide pedagogical help to the students of quantum mechanics.Latex, 9 pagesQuantum Physicstext