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chao-dyn/9303001
Far Dissipation Range of Turbulence
The very small scales of isotropic, Navier-Stokes turbulence at Reynolds number ${\cal R}_\lambda \approx 15$ are studied by high-resolution direct numerical simulation (DNS) and by integration of the direct-interaction (DIA) equations. The DNS follows the tail of the energy spectrum over more than thirty decades of ma...
1993-03-04
2009-10-22
[ "chao-dyn", "nlin.CD" ]
Shiyi Chen and Gary Doolen (CNLS, LANL), Jackson R. Herring (NCAR), Robert H. Kraichnan (Santa Fe, NM), Steven A. Orszag (Princeton Univ.), and Zhen Su She (Univ. of Arizona)
chao-dyn/9303007
On the equality of Hausdorff and box counting dimensions
By viewing the covers of a fractal as a statistical mechanical system, the exact capacity of a multifractal is computed. The procedure can be extended to any multifractal described by a scaling function to show why the capacity and Hausdorff dimension are expected to be equal.
1993-03-03
2009-10-22
[ "chao-dyn", "nlin.CD" ]
Ronnie Mainieri
chao-dyn/9302006
Teardrop and heart orbits of a swinging Atwood's Machine
An exact solution is presented for a swinging Atwood's machine. This teardrop-heart orbit is constructed using Hamilton-Jacobi theory. The example nicely illustrates the utility of the Hamilton-Jacobi method for finding solutions to nonlinear mechanical systems when more elementary techniques fail.
1993-02-23
2009-10-22
[ "chao-dyn", "nlin.CD" ]
Nicholas B. Tufillaro
chao-dyn/9302005
Cycles and Circles in Roundoff Errors
When a series of measurements is performed with increasingly coarse (or increasingly fine) precision, consecutive observations seem to be erratically distributed at first, and then organize themselves into cycles and patterns. The patterns, which arise because of roundoff errors, are related to a notion in number theor...
1993-02-23
2009-10-22
[ "chao-dyn", "nlin.CD" ]
George G. Szpiro
chao-dyn/9302004
Can averaged orbits be used to extract scaling functions?
Trajectory scaling functions are the basic element in the study of chaotic dynamical systems, from which any long time average can be computed. It has never been extracted from an experimental time series the reason being its sensitivity to noise. It is shown, by numerical simulations, that the sensitivity of the scali...
1993-02-17
2008-02-03
[ "chao-dyn", "nlin.CD" ]
Ronnie Mainieri
chao-dyn/9302003
Steady-State Electrical Conduction in the Periodic Lorentz Gas
We study nonequilibrium steady states in the Lorentz gas of periodic scatterers when an external field is applied and the particle kinetic energy is held fixed by a ``thermostat'' constructed according to Gauss' principle of least constraint (a model problem previously studied numerically by Moran and Hoover). The resu...
1993-02-08
2009-10-22
[ "chao-dyn", "nlin.CD" ]
N. I. Chernov, G. L. Eyink, J. L. Lebowitz and Ya. G. Sinai
chao-dyn/9302002
Periodic Orbit Theory of Anomalous Diffusion
We introduce a novel technique to find the asymptotic time behaviour of deterministic systems exhibiting anomalous diffusion. The procedure is tested for various classes of simple but physically relevant 1-D maps and possible relevance of our findings for more complicated problems is briefly discussed.
1993-02-05
2009-10-22
[ "chao-dyn", "nlin.CD" ]
Roberto Artuso, Giulio Casati, and Roberto Lombardi
chao-dyn/9302001
Topological organization of (low-dimensional) chaos
Recent progress toward classifying low-dimensional chaos measured from time series data is described. This classification theory assigns a template to the time series once the time series is embedded in three dimensions. The template describes the primary folding and stretching mechanisms of phase space responsible for...
1993-02-03
2008-02-03
[ "chao-dyn", "nlin.CD" ]
Nicholas B. Tufillaro
chao-dyn/9301003
Symbolic dynamics I. Finite dispersive billiards
Orbits in different dispersive billiard systems, e.g. the 3 disk system, are mapped into a topological well ordered symbol plane and it is showed that forbidden and allowed orbits are separated by a monotone pruning front. The pruning front can be approximated by a sequence of finite symbolic dynamics grammars.
1993-01-19
2009-10-22
[ "chao-dyn", "nlin.CD" ]
Kai T. Hansen
chao-dyn/9301004
Symbolic dynamics II. The stadium billiard
We construct a well ordered symbolic dynamics plane for the stadium billiard. In this symbolic plane the forbidden and the allowed orbits are separated by a monotone pruning front, and allowed orbits can be systematically generated by sequences of approximate finite grammars.
1993-01-19
2008-02-03
[ "chao-dyn", "nlin.CD" ]
Kai T. Hansen
chao-dyn/9301005
Symbolic dynamics III. Bifurcations in billiards and smooth potentials
The singular bifurcations in a dispersive billiard are discussed in terms of symbolic dynamics and is compared to an example of a bifurcation tree in a smooth potential. Possible generalizations to other smooth potentials are discussed.
1993-01-19
2009-10-22
[ "chao-dyn", "nlin.CD" ]
Kai T. Hansen
chao-dyn/9301002
An alternative to Plemelj-Smithies formulas on infinite determinants
An alternative to Plemelj - Smithies formulas for the p -regularized quantities $d^{(p)}(K)$ and $D^{(p)}(K)$ is presented which generalizes previous expressions with $p=1$ due to Grothendieck and Fredholm. It is also presented global upper bounds for these quantities. In particular we prove that $$ |d^{(p)}(K)| \le e^...
1993-01-11
2008-02-03
[ "chao-dyn", "nlin.CD" ]
Domingos H. U. Marchetti
chao-dyn/9301001
Zeta function for the Lyapunov exponent of a product of random matrices
A cycle expansion for the Lyapunov exponent of a product of random matrices is derived. The formula is non-perturbative and numerically effective, which allows the Lyapunov exponent to be computed to high accuracy. In particular, the free energy and the heat capacity are computed for the one-dimensional Ising model wit...
1993-01-11
2008-02-03
[ "chao-dyn", "nlin.CD" ]
Ronnie Mainieri
comp-gas/9312002
Cellular automaton model of reaction-transport processes
The transport and chemical reactions of solutes are modelled as a cellular automaton in which molecules of different species perform a random walk on a regular lattice and react according to a local probabilistic rule. The model describes advection and diffusion in a simple way, and as no restriction is placed on the n...
1993-12-10
2009-10-22
[ "comp-gas", "nlin.CG" ]
T. Karapiperis (Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland) and B. Blankleider (Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland, and School of Physical Sciences, Flinders University, Bedford Park, S.A. 5042, Australia (Present address))
comp-gas/9312001
Lattice Methods and Their Applications To Reacting Systems
The recent development of the lattice gas automata method and its extension to the lattice Boltzmann method have provided new computational schemes for solving a variety of partial differential equations and modeling chemically reacting systems. The lattice gas method, regarded as the simplest microscopic and kinetic a...
1993-12-08
2008-02-03
[ "comp-gas", "nlin.CG" ]
S. Chen, S. P. Dawson, G. D. Doolen, D. R. Janecky and A. Lawniczak (Theoretical Division and Center for Nonlinear Studies Los Alamos National Laboratory, Los Alamos, NM, USA)
comp-gas/9310002
Particle-Mesh Methods on the Connection Machine
We describe an efficient Particle-Mesh algorithm for the Connection Machine CM-5. Our particular method parallelizes well and the computation time per time step decreases as the particles become more clustered. We achieve floating-point computation rates of 4--5 MFlops/sec/processing node and total operations (the sum ...
1993-11-02
2009-10-22
[ "comp-gas", "astro-ph", "nlin.CG" ]
Robert Ferrell and Edmund Bertschinger
comp-gas/9310001
Elimination of Nonlinear Deviations in Thermal Lattice BGK Models
Abstracet: We present a new thermal lattice BGK model in D-dimensional space for the numerical calculation of fluid dynamics. This model uses a higher order expansion of equilibrium distribution in Maxwellian type. In the mean time the lattice symmetry is upgraded to ensure the isotropy of 6th order tensor. These manip...
1993-10-05
2008-02-03
[ "comp-gas", "nlin.CG" ]
Yu Chen, Hirotada Ohashi and Mamoru Akiyama (Department of Quantumn Engineering and Systems Science University of Tokyo, Japan)
comp-gas/9308002
Lattice Boltzmann-Langevin Equations
Intrinsic fluctuations around the solution of the lattice Boltzmann equation are described or modeled by addition of a white Gaussian noise source. For stationary states a fluctuation-dissipation theorem relates the variance of the fluctuations to the linearized Boltzmann collision operator and the pair correlation fun...
1993-09-01
2008-02-03
[ "comp-gas", "nlin.CG" ]
J.W. Dufty, M.H. Ernst
comp-gas/9308003
Instabilities and Patterns (minor technical modifications)
Violation of (semi)-detailed balance conditions in lattice gas automata gives rise to unstable spatial fluctuations that lead to phase separation and pattern formation in spinodal decomposition, unstable propagating modes, driven diffusive systems and unstable uniform flows.
1993-09-01
2008-02-03
[ "comp-gas", "nlin.CG", "nlin.PS", "patt-sol" ]
M.H. Ernst and H.J. Bussemaker (Institute for Theoretical Physics, University of Utrecht, The Netherlands)
comp-gas/9308001
Hydrodynamic behaviour of Lattice Boltzmann and Lattice BGK models
We present a numerical analysis of the validity of classical and generalized hydrodynamics for Lattice Boltzmann Equation (LBE) and Lattice BGK methods in two and three dimensions, as a function of the collision parameters of these models. Our analysis is based on the wave-number dependence of the evolution operator. G...
1993-08-30
2009-10-22
[ "comp-gas", "nlin.CG" ]
O. Behrend (Dept. of Physics, The Univ. of Edinburgh, UK), R. Harris (Dept. of Physics, The Univ. of Edinburgh, UK and Dept. of Physics and Centre for the Physics of Materials, McGill Univ., Montreal, Canada), and P. Warren (Unilever Research, Port Sunlight Laboratory, UK)
comp-gas/9307004
Abstracts on Pattern Formation and Lattice-Gas Automata
This article contains 39 pages of abstracts of invited and poster presentations for the FIELDS INSTITUTE FOR RESEARCH IN MATHEMATICAL SCIENCES AND NATO ADVANCED RESEARCH WORKSHOP PROGRAM ON PATTERN FORMATION and LATTICE-GAS AUTOMATA, JUNE 07-12, 1993
1993-08-06
2016-08-31
[ "comp-gas", "nlin.CG" ]
Gary Doolen (Los Alamos National Lab) and Anna Lawniczak (Guelph Univ.)
comp-gas/9307003
Accuracy of Discrete-Velocity BGK Models for the Simulation of the Incompressible Navier-Stokes Equations
Two discretizations of a 9-velocity Boltzmann equation with a BGK collision operator are studied. A Chapman-Enskog expansion of the PDE system predicts that the macroscopic behavior corresponds to the incompressible Navier-Stokes equations with additional terms of order Mach number squared. We introduce a fourth-order ...
1993-07-23
2008-02-03
[ "comp-gas", "nlin.CG" ]
Marc B. Reider and James D. Sterling (Center for Nonlinear Studies, Los Alamos National Laboratory)
comp-gas/9307002
A Vectorized Algorithm for Molecular Dynamics of Short Range Interacting Particles
We report on a lattice based algorithm, completely vectorized for molecular dynamics simulations. Its algorithmic complexity is of the order $O(N)$, where $N$ is the number of particles. The algorithm works very effectively when the particles have short range interaction, but it is applicable to each kind of interactio...
1993-07-19
2019-06-05
[ "comp-gas", "nlin.CG" ]
V.Buchholtz and T.P\"oschel
comp-gas/9307001
Numerical Solution of the Schroedinger Equation using a Quantum Lattice Boltzmann Equation}
The quantum Lattice Boltzmann equation (QLBe), a new variant of the lattice Boltzmann equation, specifically designed to describe non relativistic quantum motion, is validated for the case of a free-particle in (1+1) space-time dimensions. The proper parameter regime under which the method needs to be operated in order...
1993-07-07
2008-02-03
[ "comp-gas", "nlin.CG" ]
S. Succi( IBM European Center for Scientific and Engineering Computing, Roma, Italy)
comp-gas/9306005
Numerical Simulations of Particulate Suspensions via a Discretized Boltzmann Equation Part II. Numerical Results
A new and very general technique for simulating solid-fluid suspensions has been described in a previous paper (Part I); the most important feature of the new method is that the computational cost scales with the number of particles. In this paper (Part II), extensive numerical tests of the method are described; for cr...
1993-07-01
2009-10-22
[ "comp-gas", "nlin.CG" ]
Anthony J. C. Ladd (Lawrence Livermore National Laboratory)
comp-gas/9306004
Numerical Simulations of Particulate Suspensions via a Discretized Boltzmann Equation Part I. Theoretical Foundation
A new and very general technique for simulating solid-fluid suspensions is described; its most important feature is that the computational cost scales linearly with the number of particles. The method combines Newtonian dynamics of the solid particles with a discretized Boltzmann equation for the fluid phase; the many-...
1993-07-01
2009-10-22
[ "comp-gas", "nlin.CG" ]
Anthony J. C. Ladd (Lawrence Livermore National Laboratory)
comp-gas/9306003
Exact Results for the Asymmetric Simple Exclusion Process with a Blockage
We present new results for the current as a function of transmission rate in the one dimensional totally asymmetric simple exclusion process (TASEP) with a blockage that lowers the jump rate at one site from one to r < 1. Exact finite volume results serve to bound the allowed values for the current in the infinite syst...
1993-06-24
2016-08-31
[ "comp-gas", "nlin.CG" ]
Steven A. Janowsky (Rutgers) and Joel L. Lebowitz (Rutgers)
comp-gas/9306002
Initial and Boundary Conditions for the Lattice Boltzmann Method
A new approach of implementing initial and boundary conditions for the lattice Boltzmann method is presented. The new approach is based on an extended collision operator that uses the gradients of the fluid velocity. The numerical performance of the lattice Boltzmann method is tested on several problems with exact solu...
1993-06-19
2009-10-22
[ "comp-gas", "nlin.CG" ]
P. A. Skordos (LANL B258, Los Alamos, NM 87545, and Massachusetts Institute of Technology, 545 Technology Square, NE43-432, Cambridge, MA 02139)
comp-gas/9306001
Stability Analysis of Lattice Boltzmann Methods
The lattice Boltzmann equation describes the evolution of the velocity distribution function on a lattice in a manner that macroscopic fluid dynamical behavior is recovered. Although the equation is a derivative of lattice gas automata, it may be interpreted as a Lagrangian finite-difference method for the numerical si...
1993-06-15
2008-02-03
[ "comp-gas", "nlin.CG" ]
James D. Sterling (Advanced Projects Research Incorporated), and Shiyi Chen (Theoretical Division, Los Alamos National Laboratory)
comp-gas/9305005
A New Class of Cellular Automata for Reaction-Diffusion Systems
We introduce a new class of cellular automata to model reaction-diffusion systems in a quantitatively correct way. The construction of the CA from the reaction-diffusion equation relies on a moving average procedure to implement diffusion, and a probabilistic table-lookup for the reactive part. The applicability of the...
1993-05-30
2016-08-14
[ "comp-gas", "nlin.CG" ]
J\"org R. Weimar and Jean-Pierre Boon (Universit\'e Libre de Bruxelles)
comp-gas/9305004
Global Bifurcations in Rayleigh-Benard Convection: Experiments, Empirical Maps and Numerical Bifurcation Analysis
We use nonlinear signal processing techniques, based on artificial neural networks, to construct an empirical mapping from experimental Rayleigh-Benard convection data in the quasiperiodic regime. The data, in the form of a one-parameter sequence of Poincare sections in the interior of a mode-locked region (resonance h...
1993-05-27
2009-10-22
[ "comp-gas", "chao-dyn", "nlin.CD", "nlin.CG" ]
I. G. Kevrekidis and R. Rico-Martinez (Department of Chemical Engineering, Princeton University, Princeton, NJ 08544-5263), R. E. Ecke (Physics Division and Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, NM 87545), and R. M. Farber and A. S. Lapedes (Theoretical Division, Los Alamos N...
comp-gas/9305003
The non-linear response of the magnetosphere: 30 October 1978
Previous efforts to find evidence of deterministic nonlinear dynamics in the global geomagnetic system have treated the geomagnetic system as autonomous. However, the geomagnetic system is strongly driven by the stochastic solar wind. We consider the response of the magnetosphere, as given by the AE index, for one day ...
1993-05-26
2009-10-22
[ "comp-gas", "nlin.CG" ]
C. P. Price and D. Prichard (University of Alaska, Fairbanks)
comp-gas/9305002
Convergence of Convective-Diffusive Lattice Boltzmann Methods
Lattice Boltzmann methods are numerical schemes derived as a kinetic approximation of an underlying lattice gas. A numerical convergence theory for nonlinear convective-diffusive lattice Boltzmann methods is established. Convergence, consistency, and stability are defined through truncated Hilbert expansions. In this s...
1993-05-25
2008-02-03
[ "comp-gas", "nlin.CG" ]
Bracy H. Elton (Fujitsu America, Inc.), Garry H. Rodrigue (Lawrence Livermore National Laboratory and University of California, Davis), and C. David Levermore (University of Arizona)
comp-gas/9305001
Identification of Continuous-Time Dynamical Systems: Neural Network Based Algorithms and Parallel Implementation
Time-delay mappings constructed using neural networks have proven successful in performing nonlinear system identification; however, because of their discrete nature, their use in bifurcation analysis of continuous-time systems is limited. This shortcoming can be avoided by embedding the neural networks in a training a...
1993-05-13
2016-08-14
[ "comp-gas", "adap-org", "nlin.AO", "nlin.CG" ]
Robert M. Farber and Alan S. Lapedes (Theoretical Division, LANL), and Ramiro Rico-Mart\'inez and Ioannis G. Kevrekidis (Department of Chemical Engineering, Princeton University)
comp-gas/9304005
Hydrodynamic Spinodal Decomposition: Growth Kinetics and Scaling Functions
We examine the effects of hydrodynamics on the late stage kinetics in spinodal decomposition. From computer simulations of a lattice Boltzmann scheme we observe, for critical quenches, that single phase domains grow asymptotically like $t^{\alpha}$, with $\alpha \approx .66$ in two dimensions and $\alpha \approx 1.0$ i...
1993-04-28
2009-10-22
[ "comp-gas", "nlin.CG" ]
F. J. Alexander, S. Chen and D. W. Grunau (LANL)
comp-gas/9304007
Don't bleach chaotic data
A common first step in time series signal analysis involves digitally filtering the data to remove linear correlations. The residual data is spectrally white (it is ``bleached''), but in principle retains the nonlinear structure of the original time series. It is well known that simple linear autocorrelation can give r...
1993-04-28
2009-10-22
[ "comp-gas", "nlin.CG" ]
James Theiler (CNLS and T-division, LANL; and Santa Fe Institute), Stephen Eubank (CNLS and T-division, LANL; Santa Fe Institute, and Prediction Company)
comp-gas/9304006
Lattice Boltzmann Thermohydrodynamics
We introduce a lattice Boltzmann computational scheme capable of modeling thermohydrodynamic flows of monatomic gases. The parallel nature of this approach provides a numerically efficient alternative to traditional methods of computational fluid dynamics. The scheme uses a small number of discrete velocity states and ...
1993-04-28
2009-10-22
[ "comp-gas", "nlin.CG" ]
F. J. Alexander (LANL), S. Chen (LANL) and J. D. Sterling (LANL and Advanced Projects Research Incorporated)
comp-gas/9304003
The Lattice Boltzmann Equation Method for the Simulation of Compressible Fluid Flow
We systematically derived hydrodynamic equations and transport coefficients for a class of multi-speed lattice Boltzmann models in D dimensions, using the multi-scale technique. The constitutive relation of physical fluid is recovered by a modified equilibrium distribution in Maxwell-Boltzmann type. With the use of the...
1993-04-22
2008-02-03
[ "comp-gas", "nlin.CG" ]
Yu Chen, Hirotada Ohashi, and Mamoru Akiyama
comp-gas/9304004
Wavelets and Fast Numerical Algorithms
Wavelet based algorithms in numerical analysis are similar to other transform methods in that vectors and operators are expanded into a basis and the computations take place in this new system of coordinates. However, due to the recursive definition of wavelets, their controllable localization in both space and wave nu...
1993-04-22
2008-02-03
[ "comp-gas", "nlin.CG" ]
G. Beylkin (Program in Applied Mathematics, University of Colorado at Boulder)
comp-gas/9304002
Lattice Boltzmann Equation for Quantum Mechanics
It is shown that the Lattice Boltzmann equation for hydrodynamics can be extended in such a way as to describe non-relativistic quantum mechanics.
1993-04-21
2009-10-22
[ "comp-gas", "nlin.CG" ]
S. Succi (IBM ECSEC, European Center for Scientific and Engineering Computing, Rome, Italy) and R. Benzi(Physics Department, Universita' Roma II, Tor Vergata)
comp-gas/9304001
Domain Growth, Wetting and Scaling in Porous Media
The lattice Boltzmann (LB) method is used to study the kinetics of domain growth of a binary fluid in a number of geometries modeling porous media. Unlike the traditional methods which solve the Cahn-Hilliard equation, the LB method correctly simulates fluid properties, phase segregation, interface dynamics and wetting...
1993-04-21
2009-10-22
[ "comp-gas", "nlin.CG" ]
D. W. Grunau, T. Lookman, S. Y. Chen, and A. S. Lapedes (LANL)
comp-gas/9303003
Comparison of Spectral Method and Lattice Boltzmann Simulations of Two-Dimensional Hydrodynamics
We present numerical solutions of the two-dimensional Navier-Stokes equations by two methods; spectral and the novel Lattice Boltzmann Equation (LBE) scheme. Very good agreement is found for global quantities as well as energy spectra. The LBE scheme is, indeed, providing reasonably accurate solutions of the Navier-Sto...
1993-03-11
2009-10-22
[ "comp-gas", "nlin.CG" ]
D.O.Martinez and W.H.Matthaeus (Bartol Research Institute, University of Delaware), S. Chen (CNLS and Theoretical Division, Los Alamos), and D.C.Montgomery (Department of Physics and Astronomy, Dartmouth College)
comp-gas/9303002
Message-Passing Multi-Cell Molecular Dynamics on the Connection Machine 5
We present a new scalable algorithm for short-range molecular dynamics simulations on distributed memory MIMD multicomputer based on a message-passing multi-cell approach. We have implemented the algorithm on the Connection Machine 5 (CM-5) and demonstrate that meso-scale molecular dynamics with more than $10^8$ partic...
1993-03-09
2008-02-03
[ "comp-gas", "nlin.CG" ]
D. M. Beazley (Center for Nonlinear Studies, LANL) and P. S. Lomdahl (Theoretical Division, LANL)
comp-gas/9303001
A Lattice Boltzmann Model for Multi-phase Fluid Flows
We develop a lattice Boltzmann equation method for simulating multi-phase immiscible fluid flows with variation of density and viscosity, based on the model proposed by Gunstensen {\em et al} for two-component immiscible fluids. The numerical measurements of surface tension and viscosity agree well with theoretical pre...
1993-03-04
2009-10-22
[ "comp-gas", "nlin.CG" ]
Daryl Grunau (EESD, LANL), Shiyi Chen (T-Div and CNLS, LANL), and Kenneth Egger (EESD, LANL)
comp-gas/9302003
Detecting Nonlinearity in Data with Long Coherence Times
We consider the limitations of two techniques for detecting nonlinearity in time series. The first technique compares the original time series to an ensemble of surrogate time series that are constructed to mimic the linear properties of the original. The second technique compares the forecasting error of linear and no...
1993-02-26
2008-02-03
[ "comp-gas", "nlin.CG" ]
James Theiler (LANL/SFI), Paul S. Linsay (MIT), and David M. Rubin (USGS)
comp-gas/9302002
Statistical error in a chord estimator of correlation dimension: the ``rule of five''
The statistical precision of a chord method for estimating fractal dimension from a correlation integral is derived. The optimal chord length is determined, and a comparison is made to other estimators. These calculations use the approximation that all pairwise distances between the points are statistically independent...
1993-02-26
2019-06-05
[ "comp-gas", "nlin.CG" ]
James Theiler and Turab Lookman
comp-gas/9302001
Some comments on the correlation dimension of $1/f^\alpha$ noise
It has recently been observed that a stochastic (infinite degree of freedom) time series with a $1/f^\alpha$ power spectrum can exhibit a finite correlation dimension, even for arbitrarily large data sets. [A.R. Osborne and A.~Provenzale, {\sl Physica D} {\bf 35}, 357 (1989).] I will discuss the relevance of this obser...
1993-02-10
2008-02-03
[ "comp-gas", "nlin.CG" ]
James Theiler
cond-mat/9312096
Anomalous Magnetic Properties of Rh$_13$ Clusters
Electronic structures of 13-atom Rh clusters with three possible high-symmetry geometries are studied using the discrete-variational local-spin-density-functional method. The ground state is found to be the icosahedral structure, and a total magnetic moment of 15$\mu_B$ is obtained for the cluster. This value is anomal...
1993-12-31
2007-05-23
[ "cond-mat" ]
Yang Jinlong, F.Toigo, Wang Kelin, and Zhang Manhong
cond-mat/9312095
Spin-orbit Scattering and the Kondo Effect
The effects of spin-orbit scattering of conduction electrons in the Kondo regime are investigated theoretically. It is shown that due to time-reversal symmetry, spin-orbit scattering does not suppress the Kondo effect, even though it breaks spin-rotational symmetry, in full agreement with experiment. An orbital magneti...
1993-12-29
2009-10-22
[ "cond-mat" ]
Yigal Meir (Physics Department, University of California, Santa Barbara) and Ned S. Wingreen (NEC Research Institute)
cond-mat/9312094
Erratum: Properties of Odd Gap Superconductors
Erratum to cond-mat 9309014
1993-12-27
2007-05-23
[ "cond-mat" ]
A.V. Balatsky, E. Abrahams, D.J. Scalapino and J.R. Schrieffer
cond-mat/9312093
Conductance of Aharonov--Bohm Rings: From the Discrete to the Continuous Spectrum Limit
The dissipative conductance of an array of mesoscopic rings, subject to an a.c. magnetic flux is investigated. The magneto--conductance may change sign between canonical and grand-canonical statistical ensembles, as function of the inelastic level broadening and as function of the temperature. Differences between canon...
1993-12-27
2009-10-22
[ "cond-mat" ]
Alex Kamenev, Bertrand Reulet, Helene Bouchiat, and Yuval Gefen
cond-mat/9312092
Pattern Formation in Laser Induced Melting
A laser focussed onto a semiconductor film can create a disordered lamellae pattern of coexisting molten-solid regions. We present a continuum model based on the higher reflectivity of the molten regions. For large latent heat, this model becomes equivalent to a model of block copolymers. The characteristic wavenumber ...
1993-12-23
2009-10-22
[ "cond-mat" ]
Chuck Yeung and Rashmi Desai
cond-mat/9312089
Spin-gap formation in cuprates: gauge theory
We analyze the phase diagram of single and bi-layer cuprates using the gauge-field description of the t-J model. For $T>T_{\text{BE}}$ the in-plane fermion-pairing order parameter $\Delta_{\scriptscriptstyle\parallel}$ is eliminated by gauge field fluctuations, leading us to predict the absence of a spin-gap phase in s...
1993-12-22
2007-05-23
[ "cond-mat" ]
Menke U. Ubbens and Patrick A. Lee
cond-mat/9312091
Fractional Quantum Hall States in Low-Zeeman-Energy Limit
We investigate the spectrum of interacting electrons at arbitrary filling factors in the limit of vanishing Zeeman splitting. The composite fermion theory successfully explains the low-energy spectrum {\em provided the composite fermions are treated as hard-core}.
1993-12-22
2009-10-22
[ "cond-mat" ]
X.G. Wu and J.K. Jain
cond-mat/9312090
Hund's Rule for Composite Fermions
We consider the ``fractional quantum Hall atom" in the vanishing Zeeman energy limit, and investigate the validity of Hund's maximum-spin rule for interacting electrons in various Landau levels. While it is not valid for {\em electrons} in the lowest Landau level, there are regions of filling factors where it predicts ...
1993-12-22
2009-10-22
[ "cond-mat" ]
J.K. Jain and X.G.Wu
cond-mat/9312084
Magnetic Properties of the Spin-1/2 Ferromagnetic-Ferromagnetic-Antiferromagnetic Trimerized Heisenberg Chain:
The magnetic properties of the ferromagnetic-ferromagnetic-antiferromagnetic trimerized spin-1/2 Heisenberg chain are studied theoretically. The high temperature susceptibilty and the ground state saturation magnetic field are calculated and the exchange energies of the trimer compound 3CuCl${}_2\cdot$2dx are determine...
1993-12-21
2009-10-22
[ "cond-mat" ]
Kazuo Hida
cond-mat/9312087
Quantum Antiferromagnet at Finite Temperature: A Gauge Field Approach
Starting from the $CP^{N-1}$ model description of the thermally disordred phase of the $D=2$ quantum antiferromagnet, we examine the interaction of the Schwinger-boson spin-1/2 mean-field excitations with the generated gauge (chirality) fluctuations in the framework of the 1/N expansion. This interaction dramatically s...
1993-12-21
2009-10-22
[ "cond-mat" ]
Oleg Starykh and George Reiter
cond-mat/9312086
Non-Fermi Liquid Fixed Point in 2+1 Dimensions
We construct models of excitations about a Fermi surface that display calculable deviations from Fermi liquid behavior in the low-energy limit. They arise as a consequence of coupling to a Chern-Simons gauge field, whose fluctations are controlled through a ${1\over{k^x}}$ interaction. The Fermi liquid fixed point is s...
1993-12-21
2009-10-22
[ "cond-mat" ]
Chetan Nayak and Frank Wilczek
cond-mat/9312085
Parity Violation in Aharonov-Bohm Systems: The Spontaneous Hall Effect
We show how macroscopic manifestations of $P$ (and $T$) symmetry breaking can arise in a simple system subject to Aharonov-Bohm interactions. Specifically, we study the conductivity of a gas of charged particles moving through a dilute array of flux tubes. The interaction of the electrons with the flux tubes is taken t...
1993-12-21
2022-03-07
[ "cond-mat", "hep-th" ]
R. Emparan and M. A. Valle Basagoiti
cond-mat/9312083
Luttinger Liquid in a Solvable 2-Dimensional Model
We consider spinless electrons in two dimensions with the bare spectrum $\epsilon({\bf p})=|p_x|+|p_y|$. In momentum space, the interactions among electrons have a finite range $q_0$, which is small compared to the Fermi momentum. A golden rule calculation of the electron lifetime indicates a breakdown of the Landau Fe...
1993-12-21
2009-10-22
[ "cond-mat" ]
R. Hlubina
cond-mat/9312074
Electron--Vibron Interactions and Berry Phases in Charged Buckminsterfullerene: Part I
A simple model for electron-vibron interactions on charged buckminsterfullerene C$_{60}^{n-}$, $n=1,\ldots 5$, is solved both at weak and strong couplings. We consider a single $H_g$ vibrational multiplet interacting with $t_{1u}$ electrons. At strong coupling the semiclassical dynamical Jahn-Teller theory is valid. Th...
1993-12-20
2009-10-22
[ "cond-mat" ]
Assa Auerbach, Nicola Manini and Erio Tosatti
cond-mat/9312079
Magnetic Response of Disordered Ballistic Quantum Dots
The weak field average magnetic susceptibility of square shaped mesoscopic conductors is studied within a semiclassical framework. Long semiclassical trajectories are strongly affected by static disorder and differ sharply from those of clean systems. They give rise to a large linear paramagnetic susceptibility which i...
1993-12-20
2009-10-22
[ "cond-mat" ]
Yuval Gefen, Daniel Braun and Gilles Montambaux
cond-mat/9312082
Theory of Coexisting Transverse Spin Freezing and Long-Ranged Antiferromagnetic Order in Lightly Doped La_{2-x}Sr_x CuO_4
We provide an explanation of the spin-freezing transition recently observed by Chou et al. (Phys. Rev. Lett. 71, 2323 (1993)) in La_{2-x}Sr_x CuO_4 for x <= 0.02. We propose that topological excitations of the 2D Heisenberg quantum antiferromagnet having non-coplanar transverse components have a pair-interaction energy...
1993-12-20
2009-10-22
[ "cond-mat" ]
R.J. Gooding, N.M. Salem and A. Mailhot
cond-mat/9312081
Microscopic Theory of Josephson Mesoscopic Constrictions
We present a microscopic theory for the d.c. Josephson effect in model mesoscopic constrictions. Our method is based on a non-equilibrium Green function formalism which allows for a self-consistent determination of the order parameter profile along the constriction. The various regimes defined by the different length s...
1993-12-20
2009-10-22
[ "cond-mat" ]
A. Martin-Rodero, F.J. Garcia-Vidal and A. Levy-Yeyati
cond-mat/9312076
Electron--Vibron Interactions in Charged Buckminsterfullerene: Pair Energies and Spectra (Part II)
The ground state energy shifts and excitation spectra of charged buckminsterfullerene C$_{60}^{n-}$, $n=1,\ldots 5$ are calculated. The electron--vibron Hamiltonian of Part I is extended to include all $A_g$ and $H_g$ modes with experimentally determined frequencies and theoretically estimated coupling constants. Compl...
1993-12-20
2009-10-22
[ "cond-mat" ]
Nicola Manini, Erio Tosatti and Assa Auerbach
cond-mat/9312075
The orbital relaxation: a possible origin of t-J model with large J
Whereas the t-J model has gained wide popularity among physicists as a model for high-T_C superconductivity, its physical origin is not at all clear. In this communication we show that the Hubbard model with occupation-dependent hopping (t_1-t_2-t_3-U model), recently proposed to account for the relaxation of doubly-oc...
1993-12-20
2009-10-22
[ "cond-mat" ]
Alessandro Fortunelli and Anna Painelli
cond-mat/9312078
Dynamics of Nonequilibrium Processes: Surface Adsorption, Reaction-Diffusion Kinetics, Ordering and Phase Separation, a short review contributed to the book "Trends in Statistical Physics,"
This short review covers a wide selection of topics from a multidisciplinary area of dynamics of nonequilibrium systems in physics, chemistry, biology. Theoretical models of colloid particle and protein deposition and adhesion at surfaces, accompanied by relaxation processes, of reaction kinetics with and without diffu...
1993-12-20
2007-05-23
[ "cond-mat" ]
Vladimir Privman
cond-mat/9312073
Magnetic Phase Diagram of the Ferromagnetically Stacked Triangular XY Antiferromagnet: A Finite-Size Scaling Study
Histogram Monte-Carlo simulation results are presented for the magnetic-field -- temperature phase diagram of the XY model on a stacked triangular lattice with antiferromagnetic intraplane and ferromagnetic interplane interactions. Finite-size scaling results at the various transition boundaries are consistent with exp...
1993-12-19
2009-10-22
[ "cond-mat" ]
M.L. Plumer, A. Mailhot, and A. Caill\'e (Universit\'e de Sherbrooke, Sherbrooke, Qu\'ebec, Canada)
cond-mat/9312088
Quantum Group and Magnetic Translations. Bethe-Ansatz Solution for Azbel-Hofstadter Problem
We present a new approach to the problem of Bloch electrons in magnetic ( sometimes called Azbel-Hofstadter problem) field, by making explicit a natural relation between the group of magnetic translations and the quantum group $U_{q}(sl_2)$. The approach allows us to express the "mid" band spectrum of the model and the...
1993-12-19
2009-10-22
[ "cond-mat", "hep-th" ]
P.B Wiegmann and A.V.Zabrodin
cond-mat/9312072
Chaos In A Homogeneous Model For Earthquakes
We investigate the nonlinear properties of a system introduced by Burridge and Knopoff to model the dynamics of earthquakes. We find that a two-block system in a completely homogeneous configuration presents a complex behavior characterized by the presence of periodic, quasiperiodic and chaotic orbits. We have found ro...
1993-12-19
2007-05-23
[ "cond-mat" ]
Maria de Sousa Vieira
cond-mat/9312071
Effect of screening of the Coulomb interaction on the conductivity in the quantum Hall regime
We study variable range hopping in the quantum Hall effect regime in the presence of a metallic gate parallel to the plane of a two-dimensional electron gas. Screening of the Coulomb interaction by the gate causes the partial ``filling'' of the Coulomb gap in the density of localized states. At low enough temperatures ...
1993-12-18
2009-10-22
[ "cond-mat" ]
I. L. Aleiner and B. I. Shklovskii
cond-mat/9312070
A Calculation of the Exponent $\mu$ for the Gauge Glass model
Removed according to the author's request : Dear Administrator, Please,please could you remove the paper,tentatively assigned the number 9312070, with title "A calculation of the exponent mu for the gauge glass model" and just submitted to the cond-mat board as it contains an important error. Mike Moore
1993-12-17
2009-10-22
[ "cond-mat" ]
M.A. Moore and S. Murphy
cond-mat/9312069
Monte Carlo Studies of the Two-Dimensional Vortex Liquid: Absence of Transition and Dynamical Properties
Monte Carlo simulations are performed to study the properties of type-II superconducting films in a magnetic field in which the vortices move in the two-dimensional geometry represented by the surface of a sphere. No numerical evidence is found for any melting transition, although the correlation length over which vort...
1993-12-17
2009-10-22
[ "cond-mat" ]
H.H. Lee and M.A. Moore
cond-mat/9312065
Critical behaviour of a surface reaction model with infinitely many absorbing states
In a recent letter [J. Phys. A26, L801 (1993)], Yaldram et al. studied the critical behaviour of a simple lattice gas model of the CO-NO catalytic reaction. The model exhibits a second order nonequilibrium phase transition from an active state into one out of infinitely many absorbing states. Estimates for the critical...
1993-12-16
2009-10-22
[ "cond-mat" ]
Iwan Jensen
cond-mat/9312068
Propogation of Electromagnetic Waves in the Core of a String Defect in Liquid Crystals
We investigate the propagation of electromagnetic waves in the core of a winding number one string defect with isotropic core in nematic liquid crystals. We numerically solve wave equations for the TE mode and show the existence of guided modes arising due to the variation of the refractive index as a function of the s...
1993-12-16
2007-05-23
[ "cond-mat" ]
Ajit M. Srivastava and Michael Stone
cond-mat/9312066
A Monte-Carlo Analysis of Percolation of Line-Segments on a Square Lattice
We study the percolative properties of bi-dimensional systems generated by a random sequential adsorption of line-segments on a square lattice. As the segment length grows, the percolation threshold decreases, goes through a minimum and then increases slowly for large segments. We explain this non-monotonic behaviour b...
1993-12-16
2009-10-22
[ "cond-mat" ]
Y.Leroyer and E.Pommiers
cond-mat/9312067
Coulomb Interaction and the Fermi Liquid State: Solution by Bosonization
We investigate the effects of the Coulomb two-body interaction on Fermi liquids via bosonization. The Coulomb interaction is singular in the limit of low momentum transfer, and recent interest in the possibility that some singular interactions might destroy the Fermi liquid state motivate us to reexamine it. We calcula...
1993-12-16
2012-09-28
[ "cond-mat", "hep-th" ]
A. Houghton, H.-J. Kwon, J. B. Marston (Brown University) and R. Shankar (Yale University)
cond-mat/9312064
Novel Edge Excitations of Two-dimensional Electron Liquid in a Magnetic Field
We investigate the low-energy spectrum of excitations of a compressible electron liquid in a strong magnetic field. These excitations are localized at the periphery of the system. The analysis of a realistic model of a smooth edge yields new branches of acoustic excitation spectrum in addition to the well known edge ma...
1993-12-16
2009-10-22
[ "cond-mat" ]
I. L. Aleiner, and L. I. Glazman
cond-mat/9312062
Theory of spin and charge fluctuations in the Hubbard model
A self-consistent theory of both spin and charge fluctuations in the Hubbard model is presented. It is in quantitative agreement with Monte Carlo data at least up to intermediate coupling $(U\sim 8t)$. It includes both short-wavelength quantum renormalization effects, and long-wavelength thermal fluctuations which can ...
1993-12-15
2009-10-22
[ "cond-mat" ]
Y. M. Vilk, Liang Chen, and A.-M. S. Tremblay (D\'epartment de physique and Centre de recherche en physique du solide. Universit\'e de Sherbrooke, Sherbrooke, Qu\'ebec, Canada)
cond-mat/9312063
Correlations in Two-Dimensional Vortex Liquids
We report on a high temperature perturbation expansion study of the superfluid-density spatial correlation function of a Ginzburg-Landau-model superconducting film in a magnetic field. We have derived a closed form which expresses the contribution to the correlation function from each graph of the perturbation theory i...
1993-12-15
2009-10-22
[ "cond-mat" ]
Jun Hu and A. H. MacDonald (Department of Physics, Indiana University)
cond-mat/9312061
Multiband tight--binding approach to tunneling in semiconductor heterostructures: Application to $\Gamma X$ transfer in GaAs
We study tunneling in semiconductor heterostructures where the constituent materials can have a direct or indirect bandgap. In order to have a good description of the lowest conduction band, we have used the nearest-- neighbour $sp^3s^*$ tight--binding model put forward by P. Vogl {\em et al.}. A recursive Green--funct...
1993-12-15
2016-08-14
[ "cond-mat" ]
J. A. St{\o}vneng and P. Lipavsk\'y
cond-mat/9312059
Optimizing the RVB state on a triangular lattice: Presence of the long-range order
We present a Schwinger-boson approach for the RVB state of the spin-1/2 Heisenberg antiferromagnet on a triangular lattice. It is shown that Gutzwiller projection of the mean-field state that includes both antiferromagnetic and ferromagnetic decouplings leads to optimizing the RVB pair amplitudes within a self-consiste...
1993-12-15
2015-06-25
[ "cond-mat" ]
Yong-Cong Chen
cond-mat/9312060
1/z-renormalization of the mean-field behavior of the dipole-coupled singlet-singlet system HoF_3
The two main characteristics of the holmium ions in HoF_3 are that their local electronic properties are dominated by two singlet states lying well below the remaining 4f-levels, and that the classical dipole-coupling is an order of magnitude larger than any other two-ion interactions between the Ho-moments. This combi...
1993-12-15
2009-10-22
[ "cond-mat" ]
Jens Jensen
cond-mat/9312051
Nonlinear Stochastic Differential Equations and Self-Organized Criticality
Several nonlinear stochastic differential equations have been proposed in connection with self-organized critical phenomena. Due to the threshold condition involved in its dynamic evolution an infinite number of nonlinearities arises in a hydrodynamic description. We study two models with different noise correlations w...
1993-12-14
2016-11-03
[ "cond-mat" ]
Albert Diaz-Guilera (Dept. Fisica Fonamental, Univ. Barcelona)
cond-mat/9312055
Predictability of Self-Organizing Systems
We study the predictability of large events in self-organizing systems. We focus on a set of models which have been studied as analogs of earthquake faults and fault systems, and apply methods based on techniques which are of current interest in seismology. In all cases we find detectable correlations between precursor...
1993-12-14
2009-10-22
[ "cond-mat" ]
S. L. Pepke (Dept. of Physics, Univ. of California, Santa Barbara) and J. M. Carlson (Dept. of Physics, UCSB)
cond-mat/9312056
On the theory of the spin gap in bilayer cuprates
We formulate and solve a model of two planes of antiferromagnetically correlated electrons coupled together by a weak antiferromagnetic interaction of strength $\lambda$. We show that in-plane antiferromagnetic correlations dramatically enhance the pairing effect of the interplane interaction. For the case where the in...
1993-12-14
2007-05-23
[ "cond-mat" ]
L. B. Ioffe, A. I. Larkin, A. J. Millis, B. L. Altshuler
cond-mat/9312053
Accounting for both electron--lattice and electron--electron coupling in conjugated polymers: minimum total energy calculations on the Hubbard--Peierls hamiltonian
Minimum total energy calculations, which account for both electron--lattice and electron--electron interactions in conjugated polymers are performed for chains with up to eight carbon atoms. These calculations are motivated in part by recent experimental results on the spectroscopy of polyenes and conjugated polymers a...
1993-12-14
2009-10-22
[ "cond-mat" ]
Giuseppe Rossi (Ford Research Laboratory)
cond-mat/9312057
Finite-Temperature Transition into a Power-Law Spin Phase with an Extensive Zero-Point Entropy
We introduce an $xy$ generalization of the frustrated Ising model on a triangular lattice. The presence of continuous degrees of freedom stabilizes a {\em finite-temperature} spin state with {\em power-law} discrete spin correlations and an extensive zero-point entropy. In this phase, the unquenched degrees of freedom ...
1993-12-14
2009-10-22
[ "cond-mat" ]
P. Chandra, P. Coleman and L.B. Ioffe
cond-mat/9312054
Simulations of deposition growth models in various dimensions. Are overhangs important?
We present simulation results of deposition growth of surfaces in 2, 3 and 4 dimensions for ballistic deposition where overhangs are present, and for restricted solid on solid deposition where there are no overhangs. The values of the scaling exponents for the two models are found to be different, suggesting that they ...
1993-12-14
2009-10-22
[ "cond-mat" ]
David Y.K. Ko and Flavio Seno
cond-mat/9312052
Interstitials, Vacancies, and Supersolid Order in Vortex Crystals
Interstitials and vacancies in the Abrikosov phase of clean Type II superconductors are line imperfections, which cannot extend across macroscopic equilibrated samples at low temperatures. We argue that the entropy associated with line wandering nevertheless can cause these defects to proliferate at a sharp transition ...
1993-12-14
2009-10-22
[ "cond-mat" ]
Erwin Frey, David R. Nelson, and Daniel S. Fisher
cond-mat/9312058
Conductivity of CuO$_3$-Chains: Disorder versus Electron-Phonon Coupling
The optical conductivity of the CuO$_3$-chains, a subsystem of the 1-2-3 materials, is dominated by a broad peak in the mid-infrared ($\omega \approx 0.2$eV), and a slowly falling high-frequency tail. The 1D $t$-$J$-model is proposed as the relevant low-energy Hamiltonian describing the intrinsic electronic structure o...
1993-12-14
2009-10-22
[ "cond-mat" ]
Roland Fehrenbacher
cond-mat/9312049
Spectral properties of the one-dimensional Hubbard model
The spectral properties of the 1-D Hubbard model are obtained from quantum Monte Carlo simulations using the maximum entropy method. The one-particle excitations are characterized by dispersive cosine-like bands. Velocities for spin- and charge excitations are obtained that lead to a conformal charge c=0.98 +/- 0.05 fo...
1993-12-13
2009-10-22
[ "cond-mat" ]
R. Preuss, A. Muramatsu, W. von der Linden, F.F. Assaad and W. Hanke
cond-mat/9312050
Multiple Front Propagation Into Unstable States
The dynamics of transient patterns formed by front propagation in extended nonequilibrium systems is considered. Under certain circumstances, the state left behind a front propagating into an unstable homogeneous state can be an unstable periodic pattern. It is found by a numerical solution of a model of the Fr\'eederi...
1993-12-13
2015-06-25
[ "cond-mat" ]
R. Montagne, A. Amengual, E. Hernandez-Garcia (Departament de Fisica, Universitat de les Illes Balears, E-07071, Palma de Mallorca, Spain), and M. San Miguel (Departament of Mathematics, University of Arizona, Tucson, AZ)
cond-mat/9312048
Critical behavior of an interacting monomer-dimer model
We study a monomer-dimer model with repulsive interactions between the same species in one dimension. With infinitely strong interactions the model exhibits a continuous transition from a reactive phase to an inactive phase with two equivalent absorbing states. Monte Carlo simulations show that the critical behavior is...
1993-12-13
2007-05-23
[ "cond-mat" ]
Hyunggyu Park
cond-mat/9312047
Vortex Motion and Vortex Friction Coefficient in Triangular Josephson Junction Arrays
The dynamical response of triangular JJA is investigated using the RCSJ model. A flux flow regime is found to extend between a lower vortex-depinning current and a higher critical current, in agreement with previous calculations for square arrays. In the flux flow regime, the dynamical response to the bias current is r...
1993-12-12
2007-05-23
[ "cond-mat" ]
Wenbin and David G. Stroud
cond-mat/9312046
Anomalous low-temperature specific heat of the antiferromagnetic SU(N) Heisenberg model in a field
We discuss the low-temperature specific heat of the integrable SU(N)- invariant Heisenberg model in one dimension with degrees of freedom in the symmetric rank-$m$ tensor representation, especially for the antiferromagnetic coupling. It is known that the linear specific heat coefficient $\gam$ is a function of a field ...
1993-12-11
2007-05-23
[ "cond-mat" ]
K. Lee
cond-mat/9312045
Energy Decay in Burgers Turbulence and Interface Growth. the Problem of Random Initial Conditions - II
We present a study of the Burgers equation in one and two dimensions $d=1,2$ following the analytic approach indicated in the previous paper I. For the problem of the initial conditions decay we consider two classes of initial condition distributions $Q_{1,2} \sim \exp[-(1/4D)\int({\nabla}h)^2$d{\bf x}] where $h$-field...
1993-12-10
2009-10-22
[ "cond-mat" ]
Sergei E. Esipov
cond-mat/9312044
Generalized Hartree-Fock Theory and the Hubbard Model
The familiar unrestricted Hartree-Fock variational principle is generalized to include quasi-free states. As we show, these are in one-to-one correspondence with the one-particle density matrices and these, in turn provide a convenient formulation of a generalized Hartree-Fock variational principle, which includes the ...
1993-12-10
2009-10-22
[ "cond-mat" ]
Volker Bach, Elliott H. Lieb and Jan philip Solovej
cond-mat/9312039
Orbital Magnetism in Ensembles of Ballistic Billiards
We calculate the magnetic response of ensembles of small two-dimensional structures at finite temperatures. Using semiclassical methods and numerical calculation we demonstrate that only short classical trajectories are relevant. The magnetic susceptibility is enhanced in regular systems, where these trajectories appea...
1993-12-09
2007-05-23
[ "cond-mat" ]
Denis Ullmo, Klaus Richter, and Rodolfo A. Jalabert
cond-mat/9312038
Spin-Wave-Spin-Wave Interaction and the Thermodynamics of the Heisenberg Spin Chain
The low-temperature free energy of the spin S quantum Heisenberg ferromagnetic chain in a strong magnetic field is obtained in a two-particle approximation by using exact solution of two-spin-wave problem. The result is beyond the perturbation theory because it incorporates the both bound and scattering state contribut...
1993-12-09
2007-05-23
[ "cond-mat", "hep-lat", "hep-th" ]
Michael Teitelman