de Broglie's Exact Trajectories

De Broglie's quest for a wave-like approach capable of representing the position of a moving particle, is satisfied, in the case of time-independent external fields, by assuming that each particle runs along the virtual trajectories associated, under assigned starting conditions, with a time-independent Schr\"odinger (or Klein-Gordon) equation. Just like in classical Dynamics, indeed, the starting conditions determine, from the beginning, a set of virtual particle trajectories independent from the very presence of the particles.