WorldCat Identities

Shepelyansky, D. L. (Dima L.)

Works: 8 works in 17 publications in 3 languages and 119 library holdings
Genres: Conference papers and proceedings 
Roles: Opponent, Thesis advisor, 958, Author
Publication Timeline
Most widely held works by D. L Shepelyansky
Quantum computers, algorithms, and chaos = calcolatori quantistici, algoritmi e caos by International School of Physics "Enrico Fermi"( Book )

5 editions published in 2006 in English and held by 94 WorldCat member libraries worldwide

Quantum computers, algorithms and chaos : Varenna on Lake Como, Villa Monastero, 5-15 July 2005 by Giulio Casati( Book )

3 editions published in 2006 in English and held by 16 WorldCat member libraries worldwide

During the last ten years Quantum Information Processing and Communication (QIPC) has established itself as one of the new hot topic fields in physics, with the potential to revolutionize many areas of science and technology. QIPC replaces the laws of classical physics applied to computation and communication with the more fundamental laws of quantum mechanics. This becomes increasingly important due to technological progress going down to smaller and smaller scales where quantum effects start to be dominant. In addition to its fundamental nature, QIPC promises to advance computing power beyon
Application of the Google matrix methods for characterization of directed networks by Vivek Kandiah( Book )

2 editions published in 2014 in French and held by 2 WorldCat member libraries worldwide

The complex network theory is a recent field of great importance to study various systems under a graph perspective by considering a collection of interdependent objects. Among the different aspects of the complex networks, this thesis is focused on the analysis of structural properties of directed networks. The primary tool used in this work is the Google matrix method which is derived from the Markov chain theory. The construction of this matrix and its link with Markov chains are explored and the spectral properties of the eigenvalues are discussed with an emphasis on the dominant eigenvalue with its associated eigenvector(PageRank vector). The ranking system given by the PageRank is explained in detail and illustrated through several examples. The systems considered here are the DNA sequences of some animal species, the neural system of the C.elegans worm and the ancient strategy board game : the game of Go. In the first case, the statistical properties of symbolic chains are analyzed through a directed network viewpoint and a similarity measure of species based on PageRank is proposed. In the second case, the complementary ranking system (CheiRank vector) is introduced to provide a two dimensional characterization of the directed networks. In the third case, the dominant eigenvectors are used to highlight the most important moves during a game of Go and it is shown that those eigenvectors contain more information than mere frequency counts of the moves. It is also discussed that eigenvectors other than the dominant ones might contain information about some community structures of moves. These applications show how the information brought by the PageRank can be useful in various situations to gain some interesting or original insight about the studied system and how it is helping to understand the organization of the underlying directed network
Effects of Imperfections and Residual Inter-Qubit Interaction on Quantum Computing( Book )

2 editions published in 2004 in English and held by 2 WorldCat member libraries worldwide

We study the effects of static interqubit interactions on the accuracy of various quantum algorithms. Extensive numerical simulations show that their effect is stronger compared to external decoherence. Analytical approach based on Random Matrix Theory is developed. It gives universal law for fidelity decay induced by interqubit static interactions. This determines the time scale for reliable quantum computation in presence of realistic static imperfections and external decoherence. New polynomial algorithms are developed for simulation of complex dynamics in the regime of classical and quantum chaos, and Anderson metal- insulator transition. A generic quantum error correction method is developed; it allows to eliminate coherent effect of static errors. The theoretical results are confirmed by numerical computations with up to 28 qubits
Chaos dynamique dans le problème à trois corps restreint by Guillaume Rollin( Book )

2 editions published in 2015 in French and held by 2 WorldCat member libraries worldwide

This work is devoted to the study of the restricted 3-body problem and particularly to the capture-evolution-ejection process of particles by binary systems (star-planet, binary star, star-supermassive black hole, binary black hole, ...). First, using a generalized Kepler map, we describe, through the case of 1P/Halley, the chaotic dynamics of comets in the Solar System. The here considered binary system is the couple Sun-Jupiter. The symplectic application we use allows us to depict the main characteristics of the dynamics: chaotic trajectories, KAM islands associated to resonances with Jupiter orbital motion, ... We determine exactly and semi-analytically the exchange of energy (kick function) between the Solar System and 1P/Halley at its passage at perihelion. This kick function is the sum of the contributions of 3-body problems Sun-planet-comet associated to the eight planets. We show that each one of these contributions can be split in a keplerian term associated to the planet gravitational potential and a dipolar term due to the Sun movement around Solar System center of mass. We also use the generalized Kepler map to study the capture of dark matter particles by binary systems. We derive the capture cross section showing that long range capture is far more efficient than close encounter induced capture. We show the importance of the rotation velocity of the binary in the capture process. Particularly, a binary system with an ultrafast rotation velocity accumulates a density of captured matter up to 10^4 times the density of the incoming flow of matter. Finally, by direct integration of the planar restricted 3-body problem equations of motion, we study the ejection of particles initially captured by a binary system. In the case of a binary with two components of comparable masses, although almost all the particles are immediately ejected, we show, on Poincaré sections, that the trace of remaining particles in the vicinity of the binary form a fractal structure associated to a strange repeller associated to chaotic open systems. This fractal structure, also present in real space, has a shape of two arm spiral sharing similarities with spiral structures observed in galaxies such as the Milky Way
Intrication et imperfections dans le calcul quantique by Andrei A Pomeransky( Book )

1 edition published in 2004 in French and held by 1 WorldCat member library worldwide

L'information quantique est un nouveau domaine de la physique, qui consiste à employer les systèmes quantiques dans le calcul et la transmission de l'information. Les ordinateurs quantiques utilisent les lois de la mécanique quantique pour exécuter des calculs d'une manière bien plus efficace que les ordinateurs existants. Les ordinateurs quantiques seraient influencés par des perturbations diverses. Nous étudions, dans les cas de deux calculs quantiques très différents, l'efficacité des ordinateurs quantiques en présence d'imperfections statiques.Une des raisons fondamentales de l'efficacité extraordinaire de l'ordinateur quantique est l'effet de l'intrication quantique. Dans cette thèse nous étudions certaines propriétés importantes d'une certaine mesure quantitative d'intrication largement utilisée. Nous considérons également l'entropie informationnelle moyenne des états quantiques, puis nous trouvons une expression explicite pour cette quantité et étudions ses propriétés les plus importantes
Quelques aspects du chaos quantique dans les systèmes de N-corps en interaction : chaînes de spins quantiques et matrices aléatoires by Yasar Yilmaz Atas( )

1 edition published in 2014 in French and held by 1 WorldCat member library worldwide

My thesis is devoted to the study of some aspects of many body quantum interacting systems. In particular we focus on quantum spin chains. I have studied several aspects of quantum spin chains, from both numerical and analytical perspectives. I addressed especially questions related to the structure of eigenfunctions, the level densities and the spectral properties of spin chain Hamiltonians. In this thesis, I first present the basic numerical techniques used for the computation of eigenvalues and eigenvectors of spin chain Hamiltonians. Level densities of quantum models are important and simple quantities that allow to characterize spectral properties of systems with large number of degrees of freedom. It is well known that the level densities of most integrable models tend to the Gaussian in the thermodynamic limit. However, it appears that in certain limits of coupling of the spin chain to the magnetic field and for finite number of spins on the chain, one observes peaks in the level density. I will show that the knowledge of the first two moments of the Hamiltonian in the degenerate subspace associated with each peak give a good approximation to the level density. Next, I study the statistical properties of the eigenvalues of spin chain Hamiltonians. One of the main achievements in the study of the spectral statistics of quantum complex systems concerns the universal behaviour of the fluctuation of measure such as the distribution of spacing between two consecutive eigenvalues. These fluctuations are very well described by the theory of random matrices but the comparison with the theoretical prediction generally requires a transformation of the spectrum of the Hamiltonian called the unfolding procedure. For many-body quantum systems, the size of the Hilbert space generally grows exponentially with the number of particles leading to a lack of data to make a proper statistical study. These constraints have led to the introduction of a new measure free of the unfolding procedure and based on the ratio of consecutive level spacings rather than the spacings themselves. This measure is independant of the local level density. By following the Wigner surmise for the computation of the level spacing distribution, I obtained approximation for the distribution of the ratio of consecutive level spacings by analyzing random 3x3 matrices for the three canonical ensembles. The prediction are compared with numerical results showing excellent agreement. Finally, I investigate eigenfunction statistics of some canonical spin-chain Hamiltonians. Eigenfunctions together with the energy spectrum are the fundamental objects of quantum systems: their structure is quite complicated and not well understood. Due to the exponential growth of the size of the Hilbert space, the study of eigenfunctions is a very difficult task from both analytical and numerical points of view. I demonstrate that the groundstate eigenfunctions of all canonical models of spin chain are multifractal, by computing numerically the Rényi entropy and extrapolating it to obtain the multifractal dimensions
Teorii︠a︡ diffuznogo fotoėffekta v atome vodoroda by D. L Shepelyansky( Book )

in Russian and held by 1 WorldCat member library worldwide

Audience Level
Audience Level
  Kids General Special  
Audience level: 0.72 (from 0.68 for Quantum co ... to 0.99 for Quelques a ...)

Associated Subjects
Quantum computers, algorithms, and chaos = calcolatori quantistici, algoritmi e caos Quantum computers, algorithms and chaos : Varenna on Lake Como, Villa Monastero, 5-15 July 2005
Quantum computers, algorithms and chaos : Varenna on Lake Como, Villa Monastero, 5-15 July 2005
Alternative Names
Shepeli︠a︡nskiĭ, D. L.

Shepeli︠a︡nskiĭ, D. L. (Dima L.)

Shepelyansky, Dima L.