T. P. Puzynina

Polaron Model of the Formation of Hydrated Electron States

A computer simulation of the formation of photoexcited electrons in water is performed within the framework of a dynamic model. The obtained results are discussed in comparison with experimental data and theoretical estimates.

Mathematical modeling of the evolution of polaron states

The evolution of polarons in a homogeneous medium is studied depending on model parameters and initial conditions that are chosen in the form of various combinations of stationary polaron states. A computational scheme and results of numerical modeling are presented.

Numerical simulations of heat and moisture transfer subject to the phase transition

A model for the description of the heat and moisture transfer in a porous material is proposed. The density of the saturated vapor and the transfer coefficients of the liquid and vapor moistures depend on the temperature. At the same time, the conductivity coefficient of the porous material depends on the moisture. On the basis of the proposed model, a numerical simulation of the heat and moisture transfer for a drying process has been performed.

Scheme of splitting with respect to physical processes for a model of heat and moisture transfer

A difference scheme of splitting with respect to physical processes for a model of heat and moisture transfer is proposed. The model involves three physical processes—heat, liquid and saturated vapor transfer in the porous material. The density of saturated vapor and the transfer coefficients of liquid and vapor moistures depend on the temperature. At the same time, the heat capacity and conductivity of the porous material depend on moisture. On the basis of the proposed scheme of the model, a numerical simulation of the heat and moisture transfer for a drying process has been performed.

A numerical method for determination of moisture transfer coefficient according to the diffusion moisture profiles

For a set of the measured diffusion moisture profiles, a numerical method for determination of moisture transfer coefficient D(w, t) is suggested. The transfer coefficient is found as a sum of the degree \( p_0 w^{p(t)} \) and exponential \( Ae^{\mu (w - v_0 )} \) functions of the moisture concentration w, as opposite to the previous works. The exponent p(t) of the power function depends on time t. The exponential function describes profiles for large times nearby the boundary of the sample, where the moisture evaporation takes place to the atmosphere. A conservative difference scheme for numerical solution of direct problem is suggested. An inverse problem for minimization of an error functional is solved by the Newton method. Thus, a more accurate coincidence of the calculated profiles of the moisture concentration to the measured profiles is gained.

Evolution of the Continuous-Atomistic Method for the Simulation of Processes of the Interaction between Heavy Ions and Metals

The evolution of the continuous-atomistic approach to the simulation of processes of the interaction between high-energy heavy ions and metals is presented in this paper. The continuous-atomistic model is described by two different classes of equations, namely, thermal-conductivity equations with a source in the thermal-spike model and equations of motion of material points irradiated with a beam in a model of molecular dynamics. A software package is developed for simulation within the framework of the continuous-atomistic model. The results of simulation of the processes of metal-target irradiation with high-energy heavy ions depending on the parameters of the source function and the electron–phonon interaction coefficient are obtained.

Modeling structural changes in metals upon irradiation with nanoclusters by means of molecular dynamics in combination with the thermal spike model

A model of structural changes in a copper target when irradiated with Cu(147) nanoclusters is studied by means of molecular dynamics, supplemented by the thermal spike model. The results from modeling structural changes include the density and depth of penetration of the nanocluster atoms into the bombarded target, depending on the energy of the nanoclusters. The shapes of the sources in the thermal spike model for describing the energy losses of nanoclusters in a target are determined.

Quantum information transmission between two qubits through an intermediary photon gas

The theory of the quantum information transmission between two semiconductor two-level quantum dots as two qubits through an intermediary photon gas in a cavity is presented. The reduced density matrix of each two-level quantum dot is the quantum information encoded into this qubit. The quantum information exchange between two distant qubits imbedded in the photon gas is performed in the form of the mutual dependence of their reduced density matrices due to the interaction between the electrons in the qubits and the photon gas. The system of rate equations for the reduced density matrix of the two-qubit system is derived. From the solution of this system of equations it follows the mutual dependence of the reduced density matrices of two distant qubits.

Numerical solution of two-body relativistic equations for the bound-state problem with confining and Coulomb potentials

Abstract Recent investigations of the meson spectroscopy often have been based on models considering mesons as quark–antiquark bound states. These models are described by three-dimensional relativistic equations with various generalizations of Coulomb and confining potentials in momentum space. Algorithms and codes are developed for numerical investigations of these equations. The modified Generalized Continuous analogue of the Newton method is used. The numerical results demonstrate the efficiency of the created software. The code allows obtaining a numerical solution with a required accuracy. The numerical results are compared with the same results obtained by other authors.

CANM in Numerical Investigation of QCD Problems

The iterative schemes based on the Continuous analogue of the Newtons method (CANM) have been applied to the solving a number of the QCD problems.