  We argue that because of valence-fluctuation caused dynamical changes
(fluctuations) of impurity energies in the impurity band of SmB6, energies of
electrons occupying impurity sites can be due to the uncertainty principle only
estimated with corresponding uncertainty, so they can be represented by energy
intervals of non-zero width. As a conse- quence, both occupied as well as
unoccupied states can be found in the impurity band above as well as below
Fermi level even in the ground state. Therefore the subsystem of localized
charge carriers in the ground state of SmB6 cannot be described by an energy
distribution function expected for T = 0 K. This fundamental conclusion adds
another reason for absence of resistivity divergence in SmB6 at lowest
temperatures, and sheds new light on interpretation of experimental data
obtained for SmB6 and similar systems at lowest temperatures.
