Continuous Stern-Gerlach effect and the quantum-state diffusion model of state reduction

A quantum-mechanical description of the continuous Stern-Gerlach effect is developed in which environmental effects, as well as effects arising from the continuous measurement of the electronic z motion, are taken into account. Master equations are presented that describe the behavior of a quantum statistical ensemble of continuous measurement processes. On the basis of these master equations and with the help of the quantum-state diffusion model a theoretical description of individual continuous measurement processes is developed. © 1996 The American Physical Society.