34 research outputs found
The pandemic of viruses with a long incubation phase in the small world
A model of the spread of viruses in selected city and in a network of cities
is considered, taking into account the delay caused by the long incubation
period of the virus. The effect of delay effects is shown in comparison with
pandemics without such delay. A temporary asymmetry of the spread of infection
has been identified, which means that the time for a pandemic to develop
significantly exceeds the time for its completion. Model calculations of the
spread of viruses in a network of interconnected large and small cities were
carried out, and dynamics features were revealed in comparison with the spread
of viruses in a single city, including the possibility of reinfection of
megalopolis
Control of the Exciton Transfer in Quantum Dots by the Stark Effect
Resonant transfer of energy between excited states in a system of two
semiconductor quantum dots is studied theoretically. The model Hamiltonian has
been formulated, which allowed describe the impact on the dynamics of the
resonant laser pulse, the Coulomb interaction, the static Stark effect, and the
relaxation of the exciton states. Examples of calculations for efficiency of
the energy transfer under different excitation conditions are presented. The
control of the process by the level shift in a constant electric field is
demonstrated
Scenarios of Destruction for Large Network and Increasing Reliability
Damage scenarios for large networks are considered. The cascade scenario is
described by means of powers of adjacency matrix. More difficult probabilistic
variants of the large network damage are modeling by Markov chains. For
reliability augmentation of networks we add a set of random intermediate agents
with big dimensionality. It provides high reliability of all system even with
low reliability of single components. Probabilistic estimation of reliability
for reinforced network is made
Mathematical Model of Age Aggression
We formulate a mathematical model of competition for resources between
representatives of different age groups. A nonlinear kinetic
integral-differential equation of the age aggression describes the process of
redistribution of resources. It is shown that the equation of the age
aggression has a stationary solution, in the absence of age-dependency in the
interaction of different age groups. A numerical simulation of the evolution of
resources for different initial distributions has done. It is shown the
instability of the system and the existence of regimes leading to a
concentration of resources in the certain age groups
Forced quantum inverted oscillator
New exact and asymptotic results for a quantum inverted oscillator, driven by
the variable external force, are presented. To illustrate the advantages of our
approach, we applied the obtained propagator to the descriptions of evolution
the initial Gaussian wave packet under arbitrary time-dependent force or a
{\delta}-pulse action. The alternative problem of tunneling a particle through
a parabolic barrier under the influence of a low-frequency harmonic force we
solve in the quasistatic approximation. Going to the Heisenberg picture in the
Caldeira-Leggett model, we describe the influence of a time-dependent force on
an open inverted oscillator. The resulting dynamics is presented in the form of
combination the evolution of the average value of a coordinate operator and the
stochastic diffusion, being induced the wave packet spreading and the Brownian
motion
Radiation of tunnel electron
The photorecombination radiation on a neighbor center of an electron ionized
in the nonlinear tunneling regime is discussed. In the framework of the active
electron model an analytical solution of the problem has been obtained. The
analytical solution for distribution of the radiation energy spectrum has been
derived both for one and three dimension problems. The optimal parameters of
the field and the distance between quantum wells for a process of effective
photorecombination with a broad spectrum have been formulated.Comment: 8 pages, 3 figure
Interference at the tunnel ionization from double-center potential
The tunnel ionization of an electron bounded by two delta potentials under
the influence of a constant electric field is considered. The equations for the
electron current density for two different initial states are obtained. The
dependence of the emission current on the orientation of the potential with
respect to the field direction and the distance between them is studied.
Appropriate conditions for observation essential interference effects are
defined.Comment: 7 pages, 2 figure
The complex-valued encoding for dicision-making based on aliasing data
It is proposed a complex valued channel encoding for multidimensional data.
The basic approach contains overlapping of complex nonlinear mappings. Its
development leads to sparse representation of multi-channel data, increasing
their dimensions and the distance between the images
Nonlinear electron emission under the action of ultrashort laser pulse
The process of nonlinear electron emission from a metal surface under the
action of femtosecond laser pulse with moderate intensity
~W/cm is considered. One-dimensional model is formulated,
taking into account the advantage of the -polarized light in the nonlinear
emission. The time dependent Schrodinger equation with fixed equilibrium
boundary conditions is solved in the half-space using the Laplace transform
technique. The energy spectrum of emitted electrons is obtained, and its
dependence on the laser pulse parameters in compare with experimental data is
discussed.Comment: 7 pages, 3 figure
The response of an electron in the image potential on the external steady fields
The exact wave functions, which describe the states of an electron, bound in
the image potential, and the magnetic field, which is perpendicular to surface
of a metal, are obtained. The correction terms to the energy of an electron in
the first order of the perturbation theory with respect to the interaction with
the external electric field are calculated. The possibility of experimental
measurement of a local electric field by the level shift is analyzed