Measuring the squared magnetisation of a molecule
  It is proposed to shoot a molecule through a pipe of mesoscopic scale. The molecule should effectifely carry two spins and antiferromagnetic chains should be embedded in the wall of the tube. If the momentum is detected before and behind the tube, a projection of the molecular spins s1 and s2 takes place. If the molecule did not loose momentum inside the tube, it has a vanishing squared total spin in the direction of its anisotropy axis L. Whereas [L(s1+s2)]^2=1 if it did so. 
Bj\"orn Michaelis