Boundary-induced quantisation does explain the limited set of acceptable/stable wavelengths around e.g. an atom. However, what it doesn't explain, is why the a

Boundary-induced quantisation does explain the limited set of acceptable/stable wavelengths around e.g. an atom. However, what it doesn't explain, is why the amplitudes of such wavefunctions should be what they are. For example, why should the integral of the squared norm of the wavefunction for an electron be 1, if it is not a particle?