Guided plasmons in graphene p-n junctions

Spatial separation of electrons and holes in graphene gives rise to existence of plasmon waves confined to the boundary region. Theory of such guided plasmon modes within hydrodynamics of electron-hole liquid is developed. For plasmon wavelengths smaller than the size of charged domains plasmon dispersion is found to be \omega ~ q^(1/4). Frequency, velocity and direction of propagation of guided plasmon modes can be easily controlled by external electric field. In the presence of magnetic field spectrum of additional gapless magnetoplasmon excitations is obtained. Our findings indicate that graphene is a promising material for nanoplasmonics.Comment: 4+ pages, 1 figure; published version, numerical estimates adde

Quantized Transport in Graphene p-n Junctions in Magnetic Field

Recent experimental work on locally gated graphene layers resulting in p-n junctions have revealed quantum Hall effect in their transport behavior. We explain the observed conductance quantization which is fractional in the bipolar regime and integer in the unipolar regime in terms of quantum Hall edge modes propagating along and across the p-n interface. In the bipolar regime the electron and hole modes can mix at the p-n boundary, leading to current partition and quantized shot noise plateaus similar to those of conductance, while in the unipolar regime transport is noiseless. These quantum Hall phenomena reflect the massless Dirac character of charge carriers in graphene, with particle-hole interplay manifest in mode mixing and noise in the bipolar regime.Comment: 4 pages, 3 figures, available online at: http://www.sciencemag.org/cgi/content/abstract/114467

Construction of n-Lie algebras and n-ary Hom-Nambu-Lie algebras

We present a procedure to construct (n+1)-Hom-Nambu-Lie algebras from n-Hom-Nambu-Lie algebras equipped with a generalized trace function. It turns out that the implications of the compatibility conditions, that are necessary for this construction, can be understood in terms of the kernel of the trace function and the range of the twisting maps. Furthermore, we investigate the possibility of defining (n+k)-Lie algebras from n-Lie algebras and a k-form satisfying certain conditions

NECESSARY AND SUFFICIENT CONDITIONS FOR WEAK CONVERGENCE OF FIRST-RARE-EVENT TIMES FOR SEMI-MARKOV PROCESSES. II

Necessary and sufficient conditions for weak convergence of first-rareevent times for semi-Markov processes, obtained in the first part of this paper Introduction In the first part of the present paper We use all notations and conditions introduced in the first part of the present paper as well as continue numbering of sections, theorems and lemmas began there. First-rare-event times for semi-Markov processes considered in the first part of the present paper reduce to random geometric sums in the case of degenerated imbedded Markov chain. In this way, our results are connected with asymptotical results for geometric sums. Here, we would like first to mention originating papers b

Ehrenfest time dependent suppression of weak localization

The Ehrenfest time dependence of the suppression of the weak localization correction to the conductance of a {\em clean} chaotic cavity is calculated. Unlike in earlier work, no impurity scattering is invoked to imitate diffraction effects. The calculation extends the semiclassical theory of K. Richter and M. Sieber [Phys. Rev. Lett. {\bf 89}, 206801 (2002)] to include the effect of a finite Ehrenfest time.Comment: 3 Pages, 1 Figure, RevTe

ENSURING ECONOMIC SECURITY OF RUSSIA IN THE CONTEXT OF AFRICAN DEVELOPMENT TRENDS: PROBLEMS AND PROSPECTS

Abstract Purpose: A new scientific problem is posed and substantiated: the need to take into account the African economic development trends in the system of ensuring the economic security of Russia. In this context, in order to assess the security of the national economy and the competitive position of Russia, the results of scientific studies of the main development trends and threats in Africa, the position of various countries on the African continent are analyzed. Methodology: The authors are based on the analysis of current scientific literature, government official documents, and statistical reports. The main methods of research are analytical review, comparison, systematic approach, cultural and civilizational approach. Result: The article substantiates the position that taking into account the development trends of the African continent is an important component in the system of assessing the national economic security of Russia in the current period and in the future, ensuring competitiveness and strengthening the economic sovereignty of Russia, analyzing the potential of interaction with African countries in the management practice. Applications: This research can be used for the universities, teachers and education students. Novelty/Originality: The authors formulate the main directions of the activation of scientific research and concentration of practical efforts to improve the national economic security of Russia in the context of the development trend of the African continent

Spin Effects and Transport in Quantum Dots with overlapping Resonances

The role of spin is investigated in the transport through a quantum dot with two overlapping resonances (one having a width larger than the level separation and the other very narrow, cf. Silvestrov and Imry, Phys. Rev. Lett. {\bf 85}, 2565 (2000)). For a series of consecutive charging resonances, one electron from the leads populates one and the same broad level in the dot. Moreover, there is the tendency to occupy the same level also by the second electron within the same resonance. This second electron is taken from the narrow levels in the dot. The narrow levels are populated (and broad level is depopulated) via sharp rearrangements of the electronic configuration in the Coulomb blockade valleys. Possible experimental manifestations of this scenario are considered. Among these there are sharp features in the valleys and in the Mixed Valence regime and an unusual Kondo effect.Comment: 7 pages, 3 figures, just a published versio

Investment development of Russian regions backed up by natural monopolies

The article considers the issues of the relationship between business investment activities and the economic and social development of the regions. Based on the statistical data analysis it is shown that the decrease in investment activities negatively affects all key indicators of regional development after a short period of time. The article shows that a peculiarity defining Russian economy is that its significant part is actually controlled by natural monopolies. At the same time, they are strongly sensitive to all the problems of socioeconomic development of the country's territories and, therefore, are parties concerned in ensuring sustainable and qualitative growth of regional economies. Today many of the natural monopolies implement large-scale investment programs with allocated substantial resources. The analysis of these investment programs showed that they all contain components that contribute to the development of the region where the manufacturing facilities or transportation capacities of these companies are located. It is concluded that a systemic state investment policy aimed at stimulating real investments, rather than "portfolio" ones, is required to address the problem of sustainable economic growth.peer-reviewe