The view that particle diffraction logically guarantees the need for a wave interpretation has been questioned. A recent experiment has carried out the two-slit protocol with helium atoms.  The basic physics of quantal momentum transfer considered here was originally pointed out in 1923, by William Duane , before quantum mechanics was invented.  It was later recognized by Heisenberg  and by Pauling .  It was championed against orthodox ridicule by Alfred Landé .  It has also recently been considered by Van Vliet .   If the diffracting slits are considered as classical objects, theoretically ideally seamless, then a wave interpretation seems necessary, but if the diffracting slits are considered physically, as quantal objects exhibiting collective quantal motions, then the particle-only and wave-only interpretations seem perhaps equally valid.
The analysis shows, that a slow Europeanization of the Danish family reunification policies has happened, but that especially two conditions have been crucial to the process. Firstly, it is the Danish perception of sovereignty; family reunification has traditionally been seen as a purely domestic matter, which is why the Danish authoritative actors still finds it difficult to accept the EU's influence on such policies. In continuation of this point, an institutionalized double game has been taking place, in which the Danish decision makers have tried to meet both EU demands regarding more lenient family reunification policies and domestic demands for tighter policies. These actions have been an attempt to act politically and pragmatically in a cross-pressure between domestic and European policies that have pointed in opposite directions. Read the final thesis here (in Danish).