321 research outputs found
Особенности и последствия импортозамещения в России
The article discusses the features of the import substitution policy and reveals both positive and negative effects on food self-sufficiency of the population of Russia in the sanctions period. The study identified the direct effect of economic sanctions and imposed embargoes (loss of income, rise in prices for food products, reduction in the food basket), as well as the attitude of the population to the policy of food import substitution. The results of the sociological survey in the form of a volunteer survey of the population on the example of a particular region by the method of handout questionnaire are presented. It is concluded that a reorientation to the consumption of domestic food items occurred in the region while reducing the consumption of certain food items.El artículo analiza las características de la política de sustitución de importaciones e identifica consecuencias positivas y negativas para la autosuficiencia alimentaria de la población Rusa durante el período de las sanciones. El estudio reveló el impacto directo de las sanciones económicas y los embargos (pérdida de ingresos, aumento de los precios de los alimentos, reducción de la canasta de alimentos), así como las actitudes públicas hacia la política de sustitución de importaciones de alimentos. Presenta los resultados de una encuesta sociológica en forma de una encuesta voluntaria a la población sobre el ejemplo de una región específica por el método de distribución de cuestionarios. Se concluye que la región se ha desplazado al consumo de alimentos domésticos al tiempo que reduce el consumo de ciertos alimentos.В статье рассматриваются особенности политики импортозамещения и выявляются как положительные, так и отрицательные последствия для продовольственной самообеспеченности населения России в период санкций. В исследовании было выявлено прямое влияние экономических санкций и введенных эмбарго (потеря доходов, рост цен на продукты питания, сокращение продовольственной корзины), а также отношение населения к политике импортозамещения продовольствия. Представлены результаты социологического опроса в виде волонтерского опроса населения на примере конкретного региона методом раздаточного анкетирования. Сделан вывод о том, что в регионе произошла переориентация на потребление внутренних продуктов питания при одновременном сокращении потребления определенных продуктов питания
Electric circuit networks equivalent to chaotic quantum billiards
We formulate two types of electric RLC resonance network equivalent to
quantum billiards. In the network of inductors grounded by capacitors squared
resonant frequencies are eigenvalues of the quantum billiard. In the network of
capacitors grounded by inductors squared resonant frequencies are given by
inverse eigen values of the billiard. In both cases local voltages play role of
the wave function of the quantum billiard. However as different from quantum
billiards there is a heat power because of resistance of the inductors. In the
equivalent chaotic billiards we derive the distribution of the heat power which
well describes numerical statistics.Comment: 9 pages, 7 figure
Hall-like effect induced by spin-orbit interaction
The effect of spin-orbit interaction on electron transport properties of a
cross-junction structure is studied. It is shown that it results in spin
polarization of left and right outgoing electron waves. Consequently, incoming
electron wave of a proper polarization induces voltage drop perpendicularly to
the direct current flow between source and drain of the considered
four-terminal cross-structure. The resulting Hall-like resistance is estimated
to be of the order of 10^-3 - 10^-2 h/e^2 for technologically available
structures. The effect becomes more pronounced in the vicinity of resonances
where Hall-like resistance changes its sign as function of the Fermi energy.Comment: 4 pages (RevTeX), 4 figures, will appear in Phys. Rev. Let
Two-component model of a spin-polarized transport
Effect of the spin-involved interaction of electrons with impurity atoms or
defects to the transport properties of a two-dimensional electron gas is
described by using a simplifying two-component model. Components representing
spin-up and spin-down states are supposed to be coupled at a discrete set of
points within a conduction channel. The used limit of the short-range
interaction allows to solve the relevant scattering problem exactly. By varying
the model parameters different transport regimes of two-terminal devices with
ferromagnetic contacts can be described. In a quasi-ballistic regime the
resulting difference between conductances for the parallel and antiparallel
orientation of the contact magnetization changes its sign as a function of the
length of the conduction channel if appropriate model parameters are chosen.
The effect is in agreement with recent experimental observations.Comment: 4 RevTeX pages with 4 figure
The brachistochrone problem in open quantum systems
Recently, the quantum brachistochrone problem is discussed in the literature
by using non-Hermitian Hamilton operators of different type. Here, it is
demonstrated that the passage time is tunable in realistic open quantum systems
due to the biorthogonality of the eigenfunctions of the non-Hermitian Hamilton
operator. As an example, the numerical results obtained by Bulgakov et al. for
the transmission through microwave cavities of different shape are analyzed
from the point of view of the brachistochrone problem. The passage time is
shortened in the crossover from the weak-coupling to the strong-coupling regime
where the resonance states overlap and many branch points (exceptional points)
in the complex plane exist. The effect can {\it not} be described in the
framework of standard quantum mechanics with Hermitian Hamilton operator and
consideration of matrix poles.Comment: 18 page
Observation of Caustics in the Trajectories of Cold Atoms in a Linear Magnetic Potential
We have studied the spatial and temporal dynamics of a cold atom cloud in the
conservative force field of a ferromagnetic guide, after laser cooling has been
switched off suddenly. We observe outgoing 'waves' that correspond to caustics
of individual trajectories of trapped atoms. This provides detailed information
on the magnetic field, the energy distribution and the spin states.Comment: 21 pages, incl. 12 figure
Bound states in the continuum in open Aharonov-Bohm rings
Using formalism of effective Hamiltonian we consider bound states in
continuum (BIC). They are those eigen states of non-hermitian effective
Hamiltonian which have real eigen values. It is shown that BICs are orthogonal
to open channels of the leads, i.e. disconnected from the continuum. As a
result BICs can be superposed to transport solution with arbitrary coefficient
and exist in propagation band. The one-dimensional Aharonov-Bohm rings that are
opened by attaching single-channel leads to them allow exact consideration of
BICs. BICs occur at discrete values of energy and magnetic flux however it's
realization strongly depend on a way to the BIC's point.Comment: 5 pgaes, 4 figure
Dynamical spin-electric coupling in a quantum dot
Due to the spin-orbital coupling in a semiconductor quantum dot, a freely
precessing electron spin produces a time-dependent charge density. This creates
a sizeable electric field outside the dot, leading to promising applications in
spintronics. The spin-electric coupling can be employed for non-invasive single
spin detection by electrical methods. We also consider a spin relaxation
mechanism due to long-range coupling to electrons in gates and elsewhere in the
system, and find a contribution comparable to, and in some cases dominant over
previously discussed mechanisms.Comment: 4 pages, 2 figure
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