91 research outputs found
Digital matrix of the Russian economy
The article analyses the problems of digitalisation, which has become dominant in recent years, which is justified by numerous data on scientific publications, the number of patents, the volume of investments and publications in various media. The article is based on the methodology of an integrated approach and system analysis. The theoretical basis of the article was the publications of Russian researchers devoted to the problems of the Russian economy҅s digitalisation. Familiarisation with regulatory documents and government programmes, methods of comparative analysis were chosen as research methods. The methods used also included the method of expert assessments, normative and logical methods. The analysis of methods, mechanisms, tools and other aspects of updating the track of digital transformation of the Russian economy is carried out. Based on and summarizing the results of the study, nine directions for the development of end-to-end technologies have been formulated and a block diagram of the model of the government programme «Digital Economy» is presented. Separately, the culture of organisations is considered, which is a barrier to the digital transformation of companies, which evolves into a «digital culture». In conclusion, a modern rating of end-to-end trends of the digitalisation process is presented, and global end-to-end trends of digitalisation in the sectoral context demonstrating the track of development of the digital matrix of the Russian economy. The presented information will allow to navigate in the established directions of development of end-to-end technologies of the Russian economy, and to make rational management decisions to representatives of Russian business and top management of Russian companies
Does theory of quantum correction to conductivity agree with experimental data in 2D systems?
The quantum correction to the conductivity have been studied in two types of
2D heterostructures: with doped quantum well and doped barriers. The consistent
analysis shows that in the structures where electrons occupy the states in
quantum well only, all the temperature and magnetic field dependencies of the
components of resistivity tensor are well described by the theories of quantum
corrections. The contribution of electron-electron interaction to the
conductivity have been determined reliably in the structures with different
electron density. A possible reason of large scatter in experimental data
concerning the contribution of electron-electron interaction, obtained in
previous papers, and the role of the carriers, occupied the states of the doped
layers, is discussed.Comment: 10 pages with 9 figure
The domain of partial attraction of a Poisson law
Groshev gave a characterization of the union of domains of partial attraction of all Poisson laws in 1941. His classical condition is expressed by the underlying distribution function and disguises the role of the mean λ of the attracting distribution. In the present paper we start out from results of the recent “probabilistic approach” and derive characterizations for any fixed λ>0 in terms of the underlying quantile function. The approach identifies the portion of the sample that contributes the limiting Poisson behavior of the sum, delineates the effect of extreme values, and leads to necessary and sufficient conditions all involving λ. It turns out that the limiting Poisson distributions arise in two qualitatively different ways depending upon whether λ>1 or λ<1. A concrete construction, illustrating all the results, also shows that in the boundary case when λ=1 both possibilities may occur.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45254/1/10959_2005_Article_BF01047000.pd
Interplay between Coulomb Blockade and Resonant Tunneling studied by the Keldysh Green's Function Method
A theory of tunneling through a quantum dot is presented which enables us to
study combined effects of Coulomb blockade and discrete energy spectrum of the
dot. The expression of tunneling current is derived from the Keldysh Green's
function method, and is shown to automatically satisfy the conservation at DC
current of both junctions.Comment: 4 pages, 3 figures(mail if you need), use revtex.sty, error
corrected, changed titl
Electron-electron interaction at decreasing
The contribution of the electron-electron interaction to conductivity is
analyzed step by step in gated GaAs/InGaAs/GaAs heterostructures with different
starting disorder. We demonstrate that the diffusion theory works down to , where is the Fermi quasimomentum, is the mean free
paths. It is shown that the e-e interaction gives smaller contribution to the
conductivity than the interference independent of the starting disorder and its
role rapidly decreases with decrease.Comment: 5 pages, 6 figure
Electron correlation resonances in the transport through a single quantum level
Correlation effects in the transport properties of a single quantum level
coupled to electron reservoirs are discussed theoretically using a
non-equilibrium Green functions approach. Our method is based on the
introduction of a second-order self-energy associated with the Coulomb
interaction that consistently eliminates the pathologies found in previous
perturbative calculations. We present results for the current-voltage
characteristic illustrating the different correlation effects that may be found
in this system, including the Kondo anomaly and Coulomb blockade. We finally
discuss the experimental conditions for the simultaneous observation of these
effects in an ultrasmall quantum dot.Comment: 4 pages (two columns), 3 figures under reques
Effect of the Coulomb repulsion on the {\it ac} transport through a quantum dot
We calculate in a linear response the admittance of a quantum dot out of
equilibrium. The interaction between two electrons with opposite spins
simultaneously residing on the resonant level is modeled by an Anderson
Hamiltonian. The electron correlations lead to the appearence of a new feature
in the frequency dependence of the conductance. For certain parameter values
there are two crossover frequencies between a capacitive and an inductive
behavior of the imaginary part of the admittance. The experimental implications
of the obtained results are briefly discussed.Comment: 13 pages, REVTEX 3.0, 2 .ps figures from [email protected],
NUB-308
Ultrametric Logarithm Laws, II
We prove positive characteristic versions of the logarithm laws of Sullivan
and Kleinbock-Margulis and obtain related results in Metric Diophantine
Approximation.Comment: submitted to Montasefte Fur Mathemati
Transport in Coupled Quantum Dots: Kondo Effect Versus Anti-Ferromagnetic Correlation
The interplay between the Kondo effect and the inter-dot magnetic interaction
in a coupled-dot system is studied. An exact result for the transport
properties at zero temperature is obtained by diagonalizing a cluster, composed
by the double-dot and its vicinity, which is connected to leads. It is shown
that the system goes continuously from the Kondo regime to an
anti-ferromagnetic state as the inter-dot interaction is increased. The
conductance, the charge at the dots and the spin-spin correlation are obtained
as a function of the gate potential.Comment: 4 pages, 3 postscript figures. Submitted to PR
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