## 4 Discussion  
From the analysis of the graphs in Figures 6-9, it is clear that theoretical curves \(3^{\prime}\)-\(6^{\prime}\)(computed by a stricter theory, taking into account the tunneling of protons) are situated slightly higher and closer, and theoretical curves 3-6 (calculated according to the classical model of dipole polarization, taking into account only the thermal activation of protons) are located lower and a little further along the amplitude of the current density relative to the corresponding experimental maximums 2-6. In fact, this situation is quite qualitative and reflects both methods (both classical and quantum) regarding the description of properties and theoretical spectra parameters of density TSDC in HBC in the temperature range T = 100-235 K, where polarization is dipole and is related to the relaxation movement of Bjerrum orientation defects and the rotation of water molecules in the electric field.  
The theoretical curves \(2^{\prime}\) are markedly closer and curve 2 is noticeably further along the amplitude to the experimental maximum 1. Thus, considering the effects of proton tunneling on low-temperature polarization (50-100 K), the results of or the model of a double-symmetric potential pit (not considering the influence of electric field irregularities in the matter) show a marked convergence with the results of the theory and experiment (the same can be seen in Tables 1-4).  
The theoretical curves 7, 8 (calculated according to the classical linear model of dipole polarization, taking into account only the thermal activation of protons) are situated significantly lower (by three to four orders) by amplitude to the experimental maxima 6, 7. At the same time, considering the effects of proton tunneling on the nonlinear polarization model at the theoretical level, according to the curves \(7^{\prime},8^{\prime}\), provides an almost complete consistency with the results of the theory and experiment on the amplitude density TSDC in HBC.  
Thus, taking into account the effects of proton tunneling against the background of the nonlinear dependences embedded in Equation (24) on the dimensionless polarization parameters \(\mathrm{\xi_{0,pol}}\), \(\mathrm{\eta_{0,pol}}\) leads to a more rigorous effect, in comparison with the classical linear theory according to Equation (27), of the polarizing field strength \(\mathrm{E_{pol,0}}\) on polarization at high temperatures (230-550 K). First of all, this effect refers to the volume-charge polarization (290-450 K), the formation of which, in the HBC, proceeds with a significant dependence on quantum effects (the same can be seen in Tables 1-4).  
The results obtained in this paper are relevant and scientifically significant for a number of areas of modern science, particularly for the development of theoretical ideas about the quantum mechanisms of the formation of the ferroelectric state due to the tunnel motion of protons in the hydrogen sublattice of KDP, DKDP crystals, which are of significant practical importance for laser technology (regulators of radiation parameters), nonlinear optics and optoelectronics (electro-optical sensors, strain sensors of hard rocks and building materials, machine parts and mechanisms, etc.) [45; 46; 47; 48; 49; 50; 51; 52; 53; 54], and information technology (thin-film ferroelectric elements of microcircuits for high-speed, non-volatile storage devices with an abnormally long time maintaining the residual polarization (up to 10 years)) [29; 30; 31; 32; 33; 34; 35; 36; 37; 38; 39; 40; 41; 42; 43; 44].