Sech wave packets, their Wigner functions and Bohmian trajectories

The free particle non-relativistic Schrödinger evolution of a sech wave packet, and the corresponding Wigner function and Bohmian trajectories, are studied. The overall translation and dispersion dynamics are qualitatively similar to corresponding Gaussian wave packets, as is to be expected. On the other hand, certain bizarre and completely unexpected features are also observed, such as wave packet pinching and the instantaneous formation of infinitely many nodes, despite the apparent lack of an interference source.