Remarks on the Formulation of Quantum Mechanics with Classical Pictures and on Relations between Linear Scalar Fields and Hydrodynamical Fields

The formulation of quantum mechanics in terms of-the picture of trajectory ensemble or of the hydrodynamical picture, developed in a previous article, is further supplemented for some points. Indi­ vidual trajectories for some typical non-stationary state are explicitly obtained, illustrating that they generally show complicated fluctuations due to the action of quantum potential. Next, emphasis is placed. on the fact that the Schrodinger: field admits a mechanical model. Also the Klein-Gordon field is- represented with a quasi~irrotationa[ flow under some additional scalar field. This representation of Klein-Gordon field suggests its possible generalization to include the vortieal motion. Such treatments of interacting Klein.Gordon and electromagnetic fields involve the formalism of Dirac's recent classical electrodynamics as a limiting case. Some remarks are given on this Dirac's theory.. Finally; the picture of trajectory ensemble is generalized so as to represent wave equations with sources. In an appendix criticism is gi\1en on the attempt to interpret quantum mechanics ,in terms of Markoff process.