Abstract
A quantum beam of conserved particles is described as a Stationary Incoherent Superposition of Wave packets (SISOW). Mean values of a SISOW are time-independent confirming that the SISOW describes a stationary flux of particles. The SISOW is a general entity that contains the Hamiltonian eigenstates as a particular limit. The decomposition of the SISOW into wave packets provides intrinsic dynamic information which is not accessible from Hamiltonian eigenstates. Within the SISOW approach an exhaustive framework can be developed to be able to study dynamic phenomena in quantum electronic devices such us current fluctuations, relaxation and transient phenomena.