On the validity of quantum hydrodynamics for describing antidot array devices

Quantum hydrodynamic models are becoming increasingly used for modelling both conventional and novel semiconductor devices. However, there are several controversial problems which are unresolved including the form of the quantum potential in different formulations. It is shown here that present quantum hydrodynamics is not consistent with mixed quantum states in which spatial fluctuations are significant and that where transient bound state formation is possible it becomes important to add vorticity terms to account for multiply connected regions. These problems are of importance to transport studies of dense antidot systems.