 It is straightforward to see that the hitting process leads, when it occurs, to the localization of states of the particle, which are initially delocalized over distances greater than \(d\). As a simple example we can consider a single particle whose wavefunction is different from zero only in two small and far apart regions \(h\) and \(t\). Suppose that a localization occurs around \(h\); the state after the hitting is then appreciably different from zero only in a region around \(h\) itself. A completely analogous argument holds if the hitting takes place around \(t\). Regarding the possibility for the state to collapse around points, which are far from both \(h\) and \(t\), one easily sees that the probability density for such hittings , according to the multiplication rule determining \(L_i\), is practically zero; moreover, that if such a hitting were to occur, after it is normalized, the wave function of the system would remain almost unchanged.