arXiv subjects

Nikolay Dementev

Publications and source records attributed to Nikolay Dementev.

2 recordsLinked to original sources

arXiv2010

Thermodynamical insight on the role of additives in shifting the equilibrium between white and grey tin

In this study methods of statistical thermodynamics were applied to white tin - grey tin equilibrium to find if there is any correlation between Debye temperature of an additive and its effect on the equilibrium. Gibbs free energy of the transition was calculated for a composite system comprised of tin and the additive in assumption of Debye temperature of the composite system being a linear combination of Debye temperatures of the components with their respective molar fractions as weighing coefficients. Calculations showed that additives which Debye temperatures are above 214oK should stabilize grey tin, while the additives with Debye temperatures below 214oK should stabilize the white one. Devised rule corroborates with all previously reported experimental data on the effect of different additives on the transition. Predictions of the rule about non reported additives provide a mean for its experimental verification.

cond-mat.stat-mech↗

arXiv2010

Establishment of the conserved operators using variational principle

Operators play a substantial role in mathematical formalism of quantum mechanics. However, explicit forms of the operators are usually postulated, based on the intuitive assumptions. In this study, variational principle was applied to the basic equation for expectation value to vary a generalized form of operator while keeping psi-function invariable. A restriction of being expectation value invariable, allowed one to derive all possible forms of the operators corresponding to the conserved physical entities. As a result, it was found that only three distinctive forms of the conserved operators are possible, tentatively assigned to be angular momentum-like, momentum-like and total energy-like operators. Surprisingly, all operators included constant, the same one for each of the operators, therefore, making operators the quantum ones. Absence of the quantization in original assumptions suggests that quantum character of the operators and, therefore, the physical entities, is a direct consequence of the existence of the conservation laws.

quant-ph↗