Results for "Sergey P. Suetin"

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On the equivalence of the scalar and vector equilibrium problems for a pair of functions forming a Nikishin systemJun 11 2019We prove the equivalence of the vector and scalar equilibrium problems which arise naturally in the study of the limit zeros distribution of type I Hermite--Pad\'e polynomials for a pair of functions forming a Nikishin system.
On the distribution of zeros of the Hermite-Pade polynomials for three algebraic functions $1,f,f^2$ and the global topology of the Stokes lines for some differential equations of the third orderDec 26 2013The paper presents some heuristic results about the distribution of zeros of Hermite-Pade polynomials of first kind for the case of three functions $1,f,f^2$, where $f$ has the form $f(z): = \prod\limits_ {j = 1 } ^3 (z-a_j) ^ {\alpha_j} $, $\alpha_j ... More
Embedding AC Power Flow in the Complex Plane Part II: A Reliable Framework for Voltage Collapse AnalysisSep 01 2016Part II of this paper elaborates on the unique capability of the proposed power flow analysis framework to obtain the true solution corresponding to the stable operating point of a network. It explains the significance of obtaining the true solution for ... More
Embedding AC Power Flow with Voltage Control in the Complex Plane : The Case of Analytic Continuation via Padé ApproximantsMar 28 2015This paper proposes a method to embed the AC power flow problem with voltage magnitude constraints in the complex plane. Modeling the action of network controllers that regulate the magnitude of voltage phasors is a challenging task in the complex plane ... More
Heine, Hilbert, Pade, Riemann, and Stieltjes: a John Nuttall's work 25 years laterNov 26 2011In 1986 J. Nuttall published in Constructive Approximation the paper "Asymptotics of generalized Jacobi polynomials", where with his usual insight he studied the behavior of the denominators ("generalized Jacobi polynomials") and the remainders of the ... More
On the convergence of Chebyshev--Padé approximations to real-valued algebraic functionsSep 24 2010We announce some new results on the convergence of Chebyshev--Pad\'e approximations to real-valued algebraic function given on the segment $[-1,1]$. The rate of convergence on the segment and in the corresponding maximal domain of meromorphity of a given ... More
Embedding AC Power Flow in the Complex Plane Part I: Modelling and Mathematical FoundationMar 26 2016Jul 18 2016Part I of this paper embeds the AC power flow problem with voltage control and exponential load model in the complex plane. Modeling the action of network controllers that regulate the magnitude of voltage phasors is a challenging task in the complex ... More
On a new approach to the problem of the zero distribution of Hermite-Padé polynomials for a Nikishin systemMay 19 2018A new approach to the problem of the zero distribution of Hermite-Pad\'e polynomials of type I for a pair of functions $f_1,f_2$ forming a Nikishin system is discussed. Unlike the traditional vector approach, we give an answer in terms of a scalar equilibrium ... More
Trace formulas for a class of Jacobi operatorsOct 16 2013In this paper we study a class of Jacobi operators, such that each operator is generated by the unit Borel measure with a support consisting of a finite number of intervals on the real line R and a finite number of points in C, located outside the convex ... More
On the existence of compacta of minimal capacity in the theory of rational approximation of multi-valued analytic functionsMay 22 2015For an interval $E=[a,b]$ on the real line, let $\mu$ be either the equilibrium measure, or the normalized Lebesgue measure of $E$, and let $V^{\mu}$ denote the associated logarithmic potential. In the present paper, we construct a function $f$ which ... More
On the limit zero distribution of type I Hermite-Padé polynomialsJun 26 2015In this paper are discussed the results of new numerical experiments on zero distribution of type I Hermite-Pad\'e polynomials of order $n=200$ for three different collections of three functions $[1,f_1,f_2]$. These results are obtained by the authors ... More
On the convergence on nonlinear Padé--Chebyshev approximations to the multivalued analytic functions, variation of equilibrium energy and $S$-property of stationary compactsDec 01 2010Some new results on the convergence of nonlinear diagonal Pad\'e--Chebyshev approximations to multivalued analytic function given on the segment $[-1,1]$, are proved. We show that these approximations converge to the given function in the "maxmimal" domain ... More
Zero Distribution of Hermite-Padé Polynomials and Convergence Properties of Hermite Approximants for Multivalued Analytic FunctionsMar 10 2016In the paper, we propose two new conjectures about the convergence of Hermite Approximants of multivalued analytic functions of Laguerre class ${\mathscr L}$. The conjectures are based in part on the numerical experiments, made recently by the authors ... More
A Note on the Real Fermionic and Bosonic quadratic forms: Their Diagonalization and Topological InterpreationOct 28 2001Oct 31 2001We explain in this note how real fermionic and bosonic quadratic forms can be effectively diagonalized. Nothing like that exists for the general complex hermitian forms. Looks like this observation was missed in the Quantum Field theoretical literature. ... More
Plykin-like attractor in non-autonomous coupled oscillatorsNov 15 2008A system of two coupled non-autonomous oscillators is considered. Dynamics of complex amplitudes is governed by differential equations with periodic piecewise continuous dependence of the coefficients on time. The Poincar\'{e} map is derived explicitly. ... More
An example of physical system with hyperbolic attractor of Smale - Williams typeMar 18 2005A simple and transparent example of a non-autonomous flow system, with hyperbolic strange attractor is suggested. The system is constructed on a basis of two coupled van der Pol oscillators, the characteristic frequencies differ twice, and the parameters ... More
Interval regularization for imprecise linear algebraic equationsSep 27 2018In this paper, we consider the solution of ill-conditioned systems of linear algebraic equations that can be determined imprecisely. To improve the stability of the solution process, we "immerse" the original imprecise linear system in an interval system ... More
Electronic circuits manifesting hyperbolic chaos and their simulation with software package MultisimNov 24 2011We consider several electronic circuits, which represent dynamical systems with hyperbolic chaotic attractors of Smale-Williams type, and demonstrate results of their simulation using the software package NI Multisim 10. The developed approach is useful ... More
A non-autonomous flow system with Plykin type attractorJan 22 2009A non-autonomous flow system is introduced with an attractor of Plykin type that may serve as a base for elaboration of real systems and devices demonstrating the structurally stable chaotic dynamics. The starting point is a map on a two-dimensional sphere, ... More
On rational definite summationJul 24 2004We present a partial proof of van Hoeij-Abramov conjecture about the algorithmic possibility of computation of finite sums of rational functions. The theoretical results proved in this paper provide an algorithm for computation of a large class of sums ... More
Hyperbolic chaos in self-oscillating systems based on mechanical triple linkage: Testing absence of tangencies of stable and unstable manifolds for phase trajectoriesOct 13 2015Dynamical equations are formulated and a numerical study is provided for self-oscillatory model systems based on the triple linkage hinge mechanism of Thurston -- Weeks -- Hunt -- MacKay. We consider systems with holonomic mechanical constraint of three ... More
Torus Fractalization and IntermittencyDec 19 2001Apr 12 2002The bifurcation transition is studied for the onset of intermittency analogous to the Pomeau-Manneville mechanism of type-I, but generalized for the presence of a quasiperiodic external force. The analysis is concentrated on the torus-fractalization (TF) ... More
Belykh attractor in Zaslavsky map and its transformation under smoothingOct 21 2017Oct 30 2017If we allow non-smooth or discontinuous functions in definition of an evolution operator for dynamical systems, then situations of quasi-hyperbolic chaotic dynamics often occur like, for example, on attractors in model Lozi map and in Belykh map. The ... More
Numerical computation of formal solutions to interval linear systems of equationsMar 15 2019The work is devoted to the development of numerical methods for computing "formal solutions" of interval systems of linear algebraic equations. These solutions are found in Kaucher interval arithmetic, which extends and completes the classical interval ... More
The existence of a smooth interface in the evolutionary elliptic Muskat--Verigin problem with nonlinear sourceJun 29 2013Jul 02 2013We study the two-phase Muskat--Verigin free-boundary problem for elliptic equations with nonlinear sources. The existence of a smooth solution and a smooth free boundary is proved locally in time by applying the parabolic regularization of a condition ... More
Electronic properties and Fermi surface for new Fe-free layered superconductor BaTi2Bi2O from first principlesFeb 01 2013Very recently, as an important step in the development of layered Fe-free pnictide-oxide superconductors, the new phase BaTi2Bi2O was discovered which has the highest TC (about 4.6 K) among all related non-doped systems. In this Letter, we report for ... More
Fast Adaptation in Generative Models with Generative Matching NetworksDec 07 2016Despite recent advances, the remaining bottlenecks in deep generative models are necessity of extensive training and difficulties with generalization from small number of training examples. Both problems may be addressed by conditional generative models ... More
Analytical results for bond percolation and k-core sizes on clustered networksNov 27 2008Sep 22 2009An analytical approach to calculating bond percolation thresholds, sizes of $k$-cores, and sizes of giant connected components on structured random networks with non-zero clustering is presented. The networks are generated using a generalization of Trapman's ... More
Hyperdeterminants as integrable discrete systemsMar 23 2009Mar 24 2009We give the basic definitions and some theoretical results about hyperdeterminants, introduced by A. Cayley in 1845. We prove integrability (understood as 4d-consistency) of a nonlinear difference equation defined by the 2x2x2-hyperdeterminant. This result ... More
On the PSR B1133+16 optical counterpartAug 06 2013The aim of this work is confirming the optical identification of PSR B1133+16, whose candidate optical counterpart was detected in Very Large Telescope (VLT) images obtained back in 2003. We used new deep optical images of the PSR B1133+16 field obtained ... More
Attractor of Smale - Williams type in an autonomous time-delay systemNov 27 2010We propose an example of smooth autonomous system governed by differential delay equation manifesting chaotic dynamics apparently associated with hyperbolic attractor of Smale - Williams type. The general idea is to depart from a system generating successive ... More
Structural, electronic and magnetic properties of ether carbides (Fe3W3C, Fe6W6C, Co3W3C and Co6W6C) from first principles calculationsMar 31 2009First-principles FLAPW-GGA calculations have been performed with the purpose to determine the peculiarities of the structural, electronic, magnetic properties and stability for a family of related ether carbides M3W3C and M6W6C (where M= Fe and Co). The ... More
Simple and accurate analytical calculation of shortest path lengthsApr 19 2016We present an analytical approach to calculating the distribution of shortest paths lengths (also called intervertex distances, or geodesic paths) between nodes in unweighted undirected networks. We obtain very accurate results for synthetic random networks ... More
Numerical simulation of stochastic motion of vortex loops under action of random force. Evidence of the thermodynamic equilibriumOct 03 2008Numerical simulation of stochastic dynamics of vortex filaments under action of random (Langevin) force is fulfilled. Calculations are performed on base of the full Biot--Savart law for different intensities of the Langevin force. A new algorithm, which ... More
Hyperbolic attractor in a system of coupled non-autonomous van der Pol oscillators: Numerical test for expanding and contracting conesSep 04 2006We present numerical verification of hyperbolic nature for chaotic attractor in a system of two coupled non-autonomous van der Pol oscillators (Kuznetsov, Phys. Rev. Lett., 95, 144101, 2005). At certain parameter values, in the four-dimensional phase ... More
Structural, elastic and electronic properties of Ir-based carbides-antiperovskites Ir3MC (M = Ti, Zr, Nb and Ta) as predicted from first-principles calculationsJul 20 2015Structural, elastic, electronic properties and the features of inter-atomic bonding in hypothetical Ir-based carbides-antiperovskites Ir3MC (M=Ti, Zr, Nb and Ta), as predicted from first-principles calculations, have been investigated for a first time. ... More
Electronic properties of new low-temperature superconductors: 3.3K (Ni2P2)(Sr4Sc2O6) and 2.7K (Ni2As2)(Sr4Sc2O6) from first principlesNov 24 2010Based on first-principle FLAPW-GGA calculations, we have investigated structural and electronic properties of the recently synthesized tetragonal (space group P4/nmm) nickel-based pnictide oxide superconductors: 3.3K (Ni2P2)(Sr4Sc2O6) and 2.7K (Ni2As2)(Sr4Sc2O6). ... More
Diffusive Decay of the Vortex Tangle and Kolmogorov turbulence in quantum fluidsJul 03 2010The idea that chaotic set of quantum vortices can mimic classical turbulence, or at least reproduce many main features, is currently actively being developed. Appreciating significance of the challenging problem of the classical turbulence it can be expressed ... More
Heterogeneous CondensationOct 24 2007Vapor condensation on nanoparticle with radius smaller than the Kelvin radius is considered as fluctuation or as the heterogeneous nucleation. The expression for steady-state heterogeneous nucleation rate is obtained. Nucleation on negatively charged ... More
How clustering affects the bond percolation threshold in complex networksDec 21 2009Apr 16 2010The question of how clustering (non-zero density of triangles) in networks affects their bond percolation threshold has important applications in a variety of disciplines. Recent advances in modelling highly-clustered networks are employed here to analytically ... More
Prime (-1,1) and Jordan monsters and superalgebras of vector typeNov 29 2013It is proved that the prime degenerate (-1,1) algebra constructed in [13] (the (-1,1)-monster) generates the same variety of algebras as the Grassman (-1,1)-algebra. Moreover, the same variety is generated by the Grassmann envelope of any simple nonassociative ... More
Lyapunov analysis of strange pseudohyperbolic attractors: angles between tangent subspaces, local volume expansion and contractionMay 17 2018Sep 07 2018In this paper we analyze local structure of several chaotic attractors recently suggested in literature as pseudohyperbolic. The absence of tangencies and thus the presence of the pseudohyperbolicity is verified using the method of angles that includes ... More
Numerical test for hyperbolicity in chaotic systems with multiple time delaysAug 15 2017We develop an extension of the fast method of angles for hyperbolicity verification in chaotic systems with an arbitrary number of time-delay feedback loops. The adopted method is based on the theory of covariant Lyapunov vectors and provides an efficient ... More
On Brane Inflation With Volume StabilizationNov 10 2003Nov 26 2003The distance between BPS branes in string theory corresponds to a flat direction in the effective potential. Small deviations from supersymmetry may lead to a small uplifting of this flat direction and to brane inflation. However, this scenario can work ... More
Numerical test for hyperbolicity of chaotic dynamics in time-delay systemsApr 12 2016Jul 07 2016We develop a numerical test of hyperbolicity of chaotic dynamics in time-delay systems. The test is based on the angle criterion and includes computation of angle distributions between expanding, contracting and neutral manifolds of trajectories on the ... More
On Local Description of Two-Dimensional Geodesic Flows with a Polynomial First IntegralSep 10 2015In this paper we construct multiparametric families of two dimensional metrics with polynomial first integral. Such integrable geodesic flows are described by solutions of some semi-Hamiltonian hydrodynamic type system. We find infinitely many conservation ... More
Strange Nonchaotic Self-OscillatorJul 14 2016An example of strange nonchaotic attractor (SNA) is discussed in a dissipative system of mechanical nature driven by constant torque applied to one of the elements of the construction. So the external force is not oscillatory, and the system is autonomous. ... More
Violation of hyperbolicity in a diffusive medium with local hyperbolic attractorDec 28 2008May 13 2009Departing from a system of two non-autonomous amplitude equations, demonstrating hyperbolic chaotic dynamics, we construct a 1D medium as ensemble of such local elements introducing spatial coupling via diffusion. When the length of the medium is small, ... More
The effect of noise on a hyperbolic strange attractor in the system of two coupled van der Pol oscillatorsMay 01 2008We study the effect of noise for a physically realizable flow system with a hyperbolic chaotic attractor of the Smale - Williams type in the Poincare cross-section [S.P. Kuznetsov, Phys. Rev. Lett. 95, 2005, 144101]. It is shown numerically that slightly ... More
Network cloning unfolds the effect of clustering on dynamical processesAug 06 2014May 15 2015We introduce network $L$-cloning, a technique for creating ensembles of random networks from any given real-world or artificial network. Each member of the ensemble is an $L$-cloned network constructed from $L$ copies of the original network. The degree ... More
Collective Phase Chaos in the Dynamics of Interacting Oscillator EnsemblesDec 03 2010We study chaotic behavior of order parameters in two coupled ensembles of self-sustained oscillators. Coupling within each of these ensembles is switched on and off alternately, while the mutual interaction between these two subsystems is arranged through ... More
On weakly commutative triples of partial differential operatorsOct 26 2017We investigate algebraic properties of weakly commutative triples, appearing in the theory of integrable nonlinear partial differential equations. Algebraic technique of skew fields of formal pseudodifferential operators as well as skew Ore fields of ... More
Classical Mechanical Systems with one-and-a-half Degrees of Freedom and Vlasov Kinetic EquationJun 17 2013Aug 05 2013We consider non-stationary dynamical systems with one-and-a-half degrees of freedom. We are interested in algorithmic construction of rich classes of Hamilton's equations with the Hamiltonian H=p^2/2+V(x,t) which are Liouville integrable. For this purpose ... More
Semidefinite programming and arithmetic circuit evaluationDec 09 2005A rational number can be naturally presented by an arithmetic computation (AC): a sequence of elementary arithmetic operations starting from a fixed constant, say 1. The asymptotic complexity issues of such a representation are studied e.g. in the framework ... More
Cascades on a class of clustered random networksDec 16 2010Apr 05 2011We present an analytical approach to determining the expected cascade size in a broad range of dynamical models on the class of random networks with arbitrary degree distribution and nonzero clustering introduced in [M.E.J. Newman, Phys. Rev. Lett. 103, ... More
Observations of the X-ray Afterglows of GRB011211 and GRB001025 by XMM-NewtonMay 14 2002Oct 30 2002We present the XMM-Newton observations of X-ray afterglows of the gamma-ray bursts GRB 011211 and GRB 001025. For GRB 011211 XMM detected fading X-ray object with an average flux in 0.2-10 keV declining from 2.7$\times10^{-13}$ erg cm$^{-2}$ s$^{-1}$ ... More
Four-dimensional system with torus attractor birth via saddle-node bifurcation of limit cycles in content of family of blue sky catastrophesDec 02 2015A new four-dimensional model with quasi-periodic dynamics is suggested. The torus attractor originates via the saddle-node bifurcation, which may be regarded as a member of a bifurcation family embracing different types of blue sky catastrophes. Also ... More
Attractor of Smale-Williams type in autonomous distributed systemJan 02 2014We consider an autonomous system of partial differential equations for one-dimensional distributed medium with periodic boundary conditions. Dynamics in time consists of alternating birth and death of patterns with spatial phases transformed from one ... More
Gravitational fields and harmonic gauge in brane model of UniverseFeb 02 2019We suppose that our Universe is closed manifold in real embedding higher dimensional space. This model well describes expanding character of Universe where each point becomes more far from any other point with time. We have derived Klein-Gordon equation ... More
Comment on star-star relations in statistical mechanics and elliptic gamma-function identitiesJan 24 2013We prove a recently conjectured star-star relation, which plays the role of an integrability condition for a class of 2D Ising-type models with multicomponent continuous spin variables. Namely, we reduce this relation to an identity for elliptic gamma ... More
Berry-Esseen bounds in the entropic central limit theoremMay 20 2011Aug 22 2011Berry-Esseen-type bounds for total variation and relative entropy distances to the normal law are established for the sums of non-i.i.d. random variables.
Quasi-classical expansion of the star-triangle relation and integrable systems on quad-graphsFeb 23 2016Aug 18 2016In this paper we give an overview of exactly solved edge-interaction models, where the spins are placed on sites of a planar lattice and interact through edges connecting the sites. We only consider the case of a single spin degree of freedom at each ... More
A framework for analyzing contagion in assortative banking networksOct 13 2016We introduce a probabilistic framework that represents stylized banking networks with the aim of predicting the size of contagion events. Most previous work on random financial networks assumes independent connections between banks, whereas our framework ... More
Stochastic Dynamics of a Vortex Loop. Thermal EquilibriumNov 10 2000We study stochastic behavior of a single vortex loop appeared in imperfect Bose gas. Dynamics of Bose-condensate is supposed to obey Gross-Pitaevskii equation with additional noise satisfying fluctuation-dissipation relation. The corresponding Fokker-Planck ... More
RXTE observations of 4U 1630-47 during the peak of its 1998 outburstNov 18 1999We present an analysis of the RXTE observations of 4U 1630-47 during its outburst of 1998. The light curve and the spectral evolution of the outburst were distinctly different from the outbursts of the same source in 1996 and in 1999. Special emphasis ... More
Periodicity in Al/Ti superconducting single electron transistorsJun 03 2009Jun 08 2009We present experiments on single Cooper-pair transistors made of two different superconducting materials. We chose Ti and Al to create an energy gap profile such that the island has a higher gap than the leads, thereby acting as a barrier to quasiparticle ... More
The nonlinear-electrodynamic bending of the x-ray and gamma-ray in the magnetic field of pulsars and magnetarsOct 31 2001It was shown that according to the non-linear electrodynamics of vacuum electromagnetic rays should bend in the field of magnetic dipole. The angles of ray bending in the gravitational and magnetic fields of pulsars and magnetars were obtained. In the ... More
Recovery of a fast oscillating source in the heat equation by asymptotic of the solutionApr 18 2017Four problems about recovery of a high-frequency source in the one-dimension heat equation with homogeneous initial-boundary conditions by some information about partial asymptotic of its solution have solved. It is shown, that the source can be completely ... More
Meta-Learning Neural Bloom FiltersJun 10 2019There has been a recent trend in training neural networks to replace data structures that have been crafted by hand, with an aim for faster execution, better accuracy, or greater compression. In this setting, a neural data structure is instantiated by ... More
Chaotic Communication with Robust Hyperbolic Transmitter and ReceiverAug 09 2017New chaos-based communication schemes for transmission of analog and digital information are suggested. The carrier signal is produced by chaotic generator having well-defined oscillation phases at least on short time intervals. For data extraction, a ... More
Galaxies with conspicuous optical warpsJul 08 2016In this paper, we present results of a photometric and kinematic study for a sample of 13 edge-on spiral galaxies with pronounced integral-shape warps of their stellar discs. The global structure of the galaxies is analyzed on the basis of the Sloan Digital ... More
Constraining global properties of the Draco dwarf spheroidal galaxyNov 18 2005By fitting a flexible stellar anisotropy model to the observed surface brightness and line-of-sight velocity dispersion profiles of Draco we derive a sequence of cosmologically plausible two-component (stars + dark matter) models for this galaxy. The ... More
Rate of convergence and Edgeworth-type expansion in the entropic central limit theoremApr 20 2011Jul 24 2013An Edgeworth-type expansion is established for the entropy distance to the class of normal distributions of sums of i.i.d. random variables or vectors, satisfying minimal moment conditions.
Photogalvanic effect in HgTe/CdTe topological insulator due to edge-bulk optical transitionsMay 30 2015Sep 21 2015We study theoretically 2D HgTe/CdTe quantum well topological insulator (TI) illuminated by circularly polarized light with frequencies higher than the difference between the equilibrium Fermi level and the bottom of the conduction band (THz range). We ... More
Simulation of Many-Body Hamiltonians using Perturbation Theory with Bounded-Strength InteractionsMar 18 2008We show how to map a given n-qubit target Hamiltonian with bounded-strength k-body interactions onto a simulator Hamiltonian with two-body interactions, such that the ground-state energy of the target and the simulator Hamiltonians are the same up to ... More
Brillouin zone spin filtering mechanism of enhanced TMR and correlation effects in Co(0001)/h-BN/Co(0001) magnetic tunnel junctionApr 04 2015The 'Brillouin zone spin filtering' mechanism of enhanced tunneling magnetoresistance (TMR) is described for magnetic tunnel junctions (MTJ) and studied on an example of the MTJ with hcp Co electrodes and hexagonal BN (h-BN) spacer. Our calculations based ... More
Hyperbolic Chaos of Turing PatternsJan 19 2012May 10 2012We consider time evolution of Turing patterns in an extended system governed by an equation of the Swift-Hohenberg type, where due to an external periodic parameter modulation long-wave and short-wave patterns with length scales related as 1:3 emerge ... More
Dynamics of Small Perturbations of Orbits on a Torus in a Quasiperiodically Forced 2D Dissipative MapJun 22 2005Jun 22 2005We consider the dynamics of small perturbations of stable two-frequency quasiperiodic orbits on an attracting torus in the quasiperiodically forced Henon map. Such dynamics consists in an exponential decay of the radial component and in a complex behaviour ... More
A "saddle-node" bifurcation scenario for birth or destruction of a Smale-Williams solenoidJan 31 2012Formation or destruction of hyperbolic chaotic attractor under parameter variation is considered with an example represented by Smale--Williams solenoid in stroboscopic Poincar\'{e} map of two alternately excited non-autonomous van der Pol oscillators. ... More
Hyperbolic attractor of Smale-Williams type in a system of two coupled non-autonomous amplitude equationsApr 23 2008Recently, a system with uniformly hyperbolic attractor of Smale-Williams type has been suggested [Kuznetsov, Phys. Rev. Lett., 95, 144101, 2005]. This system consists of two coupled non-autonomous van der Pol oscillators and admits simple physical realization. ... More
Electron Beam Instability in Left-Handed MediaApr 08 2008We predict that two electron beams can develop an instability when passing through a slab of left-handed media (LHM). This instability, which is inherent only for LHM, originates from the backward Cherenkov radiation and results in a self-modulation of ... More
On the Correlated X-ray and Optical Evolution of SS CygniOct 15 2003We have analyzed the variability and spectral evolution of the prototype dwarf nova system SS Cygni using RXTE data and AAVSO observations. A series of pointed RXTE/PCA observations allow us to trace the evolution of the X-ray spectrum of SS Cygni in ... More
The limitations of discrete-time approaches to continuous-time contagion dynamicsFeb 22 2016Continuous-time Markov process models of contagions are widely studied, not least because of their utility in predicting the evolution of real-world contagions and in formulating control measures. It is often the case, however, that discrete-time approaches ... More
Transport and localization in periodic and disordered graphene superlatticesOct 06 2008Nov 02 2008We study charge transport in one-dimensional graphene superlattices created by applying layered periodic and disordered potentials. It is shown that the transport and spectral properties of such structures are strongly anisotropic. In the direction perpendicular ... More
The Determination of Microscopic Surface Tension of Liquids with a Curved Interphase Boundary by Means of Positron SpectroscopySep 30 2002The method for determination the microscopic surface tension $\sigma(R)$ of nanobubbles is developed based on the new elaboration of the positronium bubble model. In contrast to existing structureless Ps bubble models, our version contains experimentally ... More
Stellar Feedback in Dwarf Galaxy FormationNov 29 2007Dwarf galaxies pose significant challenges for cosmological models. In particular, current models predict a dark matter density that is divergent at the center, in sharp contrast with observations which indicate an approximately constant central density ... More
Stochastic Stability of Monotone Economies in Regenerative EnvironmentsSep 08 2014Feb 03 2016We introduce and analyse a new class of monotone stochastic recursions in a regenerative environment which is essentially broader than that of Markov chains. We prove stability theorems and apply our results to two canonical models in recursive economics, ... More
Generalized Zero Range Potentials and Multi-Channel Electron-Molecule ScatteringSep 09 2002A multi-channel scattering problem is studied from a point of view of integral equations system. The system appears while natural one-particle wave function equation of the electron under action of a potential with non-intersecting ranges is considered. ... More
Approximate Differentiability of Mappings of Carnot-Carathéodory SpacesJun 22 2012Feb 05 2013We study the approximate differentiability of measurable mappings of Carnot--Carath\'eodory spaces. We show that the approximate differentiability almost everywhere is equivalent to the approximate differentiability along the basic horizontal vector fields ... More
Interlayer tunneling spectroscopy of graphite at high magnetic field oriented parallel to the layersDec 20 2012Jun 10 2013Interlayer tunneling in graphite mesa-type structures is studied at a strong in-plane magnetic field $H$ up to 55 T and low temperature $T=1.4$ K. The tunneling spectrum $dI/dV$ vs. $V$ has a pronounced peak at a finite voltage $V_0$. The peak position ... More
Light modulation in planar aligned short-pitch deformed-helix ferroelectric liquid crystalsAug 20 2015We study both experimentally and theoretically modulation of light in a planar aligned deformed-helix ferroelectric liquid crystal (DHFLC) cell with subwavelength helix pitch, which is also known as a short-pitch DHFLC. In our experiments, azimuthal angle ... More
Asymptotics of type I Hermite-Padé polynomials for semiclassical functionsFeb 04 2015May 19 2015Type I Hermite--Pad\'e polynomials for a set of functions $f_0, f_1, ..., f_s$ at infinity, $Q_{n,0}$, $Q_{n,1}$, ..., $Q_{n,s}$, is defined by the asymptotic condition $$ R_n(z):=\bigl(Q_{n,0}f_0+Q_{n,1}f_1+Q_{n,2}f_2+...+Q_{n,s}f_s\bigr)(z) =\mathcal ... More
Partial hyperbolicity and central shadowingDec 19 2011Feb 11 2012We study shadowing property for a partially hyperbolic diffeomorphism $f$. It is proved that if $f$ is dynamically coherent then any pseudotrajectory can be shadowed by a pseudotrajectory with "jumps" along the central foliation. The proof is based on ... More
Some numerical results on the behavior of zeros of the Hermite-Padé polynomialsJan 28 2015We introduce and analyze some numerical results obtained by the authors experimentally. These experiments are related to the well known problem about the distribution of the zeros of Hermite--Pad\'e polynomials for a collection of three functions $[f_0 ... More
Study of internal wave breaking dependence on stratificationJun 26 2012Mixing effect in a stratified fluid is considered and examined. Euler equations for incompressible fluid stratified by a gravity field are applied to state a mathematical problem and describe the effect. It is found out that a system of Euler equations ... More
On uniquely k-determined permutationsOct 10 2006There are several approaches to study occurrences of consecutive patterns in permutations such as the inclusion-exclusion method, the tree representations of permutations, the spectral approach and others. We propose yet another approach to study occurrences ... More
About Landau-Hopf scenario in a system of coupled self-oscillatorsMar 22 2013The conditions are discussed for which an ensemble of interacting oscillators may demonstrate the Landau-Hopf scenario of successive birth of multi-frequency quasi-periodic motions. A model is proposed that is a network of five globally coupled oscillators ... More
The Complexity of Stoquastic Local Hamiltonian ProblemsJun 16 2006Oct 02 2007We study the complexity of the Local Hamiltonian Problem (denoted as LH-MIN) in the special case when a Hamiltonian obeys conditions of the Perron-Frobenius theorem: all off-diagonal matrix elements in the standard basis are real and non-positive. We ... More
The orbit and dynamical evolution of the Chelyabinsk objectDec 05 2014The orbit of the Chelyabinsk object is calculated, applying the least-squares method directly to astrometric positions. The dynamical evolution of this object in the past is studied by integrating equations of motion for particles with orbits from the ... More
On financial applications of the two-parameter Poisson-Dirichlet distributionJan 08 2015Jul 08 2015Capital distribution curve is defined as log-log plot of normalized stock capitalizations ranked in descending order. The curve displays remarkable stability over periods of time. Theory of exchangeable distributions on set partitions, developed for purposes ... More