number) in this case with the period corresponding to the flux quantum inside each loop. In the experiments we indeed observe such digital type oscillations of voltage, Fig. 3. The observed periodicity leaves no doubt that the voltage jumps up and down are a consequence of the change of $n _{u}$ and $n _{d}$. The period of the digital type oscillations in magnetic field $B _{0}  =  \Phi _{0}/S$ corresponds to the flux quantum $\Phi _{0} \approx 20.7  \ Oe \ \mu m^{2}$ inside the loop both with square side $a \approx  20 \ \mu m$ and with $a \approx  4 \ \mu m$: the period $B _{0} \approx 0.053 \ Oe $ observed in the first case corresponds to the area $S = \Phi _{0}/B _{0} \approx 390 \ \mu m^{2} \approx a^{2} $ and the period $B _{0} \approx 1.2 \ Oe $ observed in the second case corresponds to the area $S = \Phi _{0}/B _{0} \approx 17 \ \mu m^{2} \approx a^{2}$. We observed more than 110 voltage jump up and down at measurement of the structure with square side $a \approx  20 \ \mu m$ in the magnetic field from $B = -3 \ Oe$ 