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Condensed Matter papers — page 92

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Energy price risk management
The price of electricity is far more volatile than that of other commodities normally noted for extreme volatility. Demand and supply are balanced on a knife-edge because electric power cannot be…
Rafal WeronMar 13, 2001
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Modeling electricity loads in California: a continuous-time approach
In this paper we address the issue of modeling electricity loads and prices with diffusion processes. More specifically, we study models which belong to the class of generalized Ornstein-Uhlenbeck…
Rafal Weron, B. Kozlowska, J. Nowicka-ZagrajekMar 12, 2001
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Levy-stable distributions revisited: tail index > 2 does not exclude the Levy-stable regime
Power-law tail behavior and the summation scheme of Levy-stable distributions is the basis for their frequent use as models when fat tails above a Gaussian distribution are observed. However, recent…
Rafal WeronMar 12, 2001
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Interplay of linear and nonlinear impurities in the formation of stationary localized states
Formation of stationary localized states in one-dimensional chain as well as in a Cayley tree due to a linear impurity and a nonlinear impurity is studied. Furthermore, a one-dimensional chain with…
Bikash C. Gupta, Sang Bub LeeMar 12, 2001
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Single hole spectral function and spin-charge separation in the t-J model
Worm algorithm quantum Monte Carlo simulations of the hole Green function with subsequent spectral analysis were performed for J/t 0.1, 0.2, 0.4 on lattices with up to LxL=32x32 sites at temperatures…
A. Mishchenko, N. V. Prokof'ev, B. V. SvistunovMar 12, 2001
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The low-lying excitations of polydiacetylene
The Pariser-Parr-Pople Hamiltonian is used to calculate and identify the nature of the low-lying vertical transition energies of polydiacetylene. The model is solved using the density matrix…
Alan Race, W. Barford, Robert J. BursillMar 11, 2001
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Monte Carlo simulation of O(2) phi4 field theory in three dimensions
Using standard numerical Monte Carlo lattice methods, we study non-universal properties of the phase transition of three-dimensional phi4 theory of a 2-component real field phi = (phi1,phi2) with…
Peter Arnold, Guy D. MooreMar 9, 2001
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Transition temperature of a dilute homogeneous imperfect Bose gas
The leading-order effect of interactions on a homogeneous Bose gas is theoretically predicted to shift the critical temperature by an amount Δ = # ascatt n1/3 T0 from the ideal gas result…
Peter Arnold, Guy D. MooreMar 9, 2001
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Resonant Andreev reflections in superconductor-carbon-nanotube devices
Resonant Andreev reflection through superconductor-carbon-nanotube devices was investigated theoretically with a focus on the superconducting proximity effect. Consistent with a recent experiment, we…
Yadong Wei, Jian Wang, Hong Guo et al.Mar 9, 2001
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Comment on ``Density-matrix renormalization-group method for excited states''
In a Physical Review B paper Chandross and Hicks claim that an analysis of the density-density correlation function in the dimerised Hubbard model of polyacetylene indicates that the optical exciton…
Robert J. BursillMar 8, 2001
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Surface effects in multiband superconductors. Application to MgB2
Metals with many bands at the Fermi level can have different band dependent gaps in the superconducting state. The absence of translational symmetry at an interface can induce interband scattering…
E. Bascones, F. GuineaMar 8, 2001
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Short wavelength spectrum and Hamiltonian stability of vortex rings
We compare dynamical and energetical stability criteria for vortex rings. It is argued that vortex rings will be intrinsically unstable against perturbations with short wavelengths below a critical…
Uwe R. Fischer, Nils SchopohlMar 8, 2001
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How to split the electron in one dimension
Using the example of the Davydov soliton - a large acoustic polaron in one dimension - we demonstrate that the electron wave function can be fissioned in two or more long-lived, well-localized and…
Eugene B. Kolomeisky, T. J. Newman, J. P. StraleyMar 7, 2001
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Electrostatic force spectroscopy of a single InAs quantum dot
Electrostatic force microscopy at cryogenic temperatures was used to probe the electrostatic interaction between a conductive atomic force microscopy tip and electronic charges trapped in an InAs…
Aykutlu Dâna, Charles Santori, Yoshihisa YamamotoMar 6, 2001
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The supersymmetric technique for random-matrix ensembles with zero eigenvalues
The supersymmetric technique is applied to computing the average spectral density near zero energy in the large-N limit of the random-matrix ensembles with zero eigenvalues: B, DIII-odd, and the…
D. A. IvanovMar 6, 2001
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Critical Temperature Shift in Weakly Interacting Bose Gas
With a high-performance Monte Carlo algorithm we study the interaction-induced shift of the critical point in weakly interacting three-dimensional |ψ|4-theory (which includes quantum Bose gas). In…
Nikolay Prokof'ev, Boris Svistunov, V. A. KashurnikovMar 6, 2001
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Worm algorithms for classical statistical models
We show that high-temperature expansions may serve as a basis for the novel approach to efficient Monte Carlo simulations. "Worm" algorithms utilize the idea of updating closed path…
Nikolay Prokof'ev, Boris SvistunovMar 6, 2001
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Rheology of a confined granular material
We study the rheology of a granular material slowly driven in a confined geometry. The motion is characterized by a steady sliding with a resistance force increasing with the driving velocity and the…
Guillaume Ovarlez, Evelyne Kolb, Eric ClémentMar 6, 2001
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Free Random Levy Variables and Financial Probabilities
We suggest that Free Random Variables, represented here by large random matrices with spectral Levy disorder, may be relevant for several problems related to the modeling of financial systems. In…
Z. Burda, J. Jurkiewicz, M. A. Nowak et al.Mar 6, 2001
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Localization transition in the Mermin model
We study the dynamical properties of the Mermin model, a simple quantum dissipative model with a monochromatic environment, using analytical and numerical methods. Our numerical results show that the…
Gregory Levine, V. N. MuthukumarMar 6, 2001
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Free Levy Matrices and Financial Correlations
We consider a covariance matrix composed of asymmetric and free random Levy matrices. We use the results of free random variables to derive an algebraic equation for the resolvent and solve it to…
Z. Burda, J. Jurkiewicz, M. A. Nowak et al.Mar 5, 2001
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Levy Matrices and Financial Covariances
In a given market, financial covariances capture the intra-stock correlations and can be used to address statistically the bulk nature of the market as a complex system. We provide a statistical…
Z. Burda, J. Jurkiewicz, M. A. Nowak et al.Mar 5, 2001
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Dynamic Ordering and Transverse Depinning of a Driven Elastic String in a Disordered Media
We examine the dynamics of an elastic string interacting with quenched disorder driven perpendicular and parallel to the string. We show that the string is the most disordered at the depinning…
C. Reichhardt, C. J. OlsonMar 5, 2001
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Excited states of linear polyenes
We present density matrix renormalisation group calculations of the Pariser- Parr-Pople-Peierls model of linear polyenes within the adiabatic approximation. We calculate the vertical and relaxed…
William Barford, Robert J. Bursill, Mikhail Yu LavrentievMar 5, 2001
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Bosons in cigar-shape traps: Thomas-Fermi regime, Tonks-Girardeau regime, and between
We present a quantitative analysis of the experimental accessibility of the Tonks-Girardeau gas in the current day experiments with cigar-trapped alkalis. For this purpose we derive, using a Bethe…
Vanja Dunjko, Vincent Lorent, Maxim OlshaniiMar 4, 2001
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