2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/106717A stochastic model for nondemolition continuous measurement in a quantum system is given. It is shown that the posterior dynamics, including a continuous collapse of the wave function, is described by a nonlinear stochastic wave equation. For a particle in an electromagnetic field it reduces the Schroedinger equation with extra imaginary stochastic potentials.7 pages. See also related papers at http://www.maths.nott.ac.uk/personal/vpb/research/evo_equ.html and http://www.maths.nott.ac.uk/personal/vpb/research/fil_con.htmlQuantum Physicstext