R.E Callaghan, P. Van Reeth and B. J. Hiley
Quantum trajectories: real or surreal? the stern-gerlach experiment revisited
The notion of a quantum particle trajectory as evaluated from the Bohmian approach to quantum mechanics is certainly controversial and has been debated by many authors over the years. One of these critiques has lead to the conclusion that the trajectories should be called surreal as they disagree with so-called observed tracts in a two-magnet Stern-Gerlach thought experiment . We have investigated both the two- and three-magnet Stern-Gerlach set-up with the Bohmian approach using both the propagator and the impulse approximation methods and show that the trajectories are real and follow the flow of momentum flux, contradicting the implications of the analysis given in . Together with the trajectories we will also present results for the osmotic/imaginary velocities and the quantum potential and discuss potential experimental implications.
 B.Englert, M. O. Scully, G. Süssmann, and H. Walther Z. Naturforsch. 47A, 1175 (1992)