Weak Localization in Semiconductor Multi-Quantum Well StructuresWe have studied the phenomenon of weak localization in multi-quantum-well (MQW) structures in the regime of weak tunneling, when superlattice minibands are not formed. We have calculated the effect…F. G. Pikus, G. E. Pikus·Oct 17, 1997SaveLearn
Peculiarities of phonon spectra and lattice heat capacity in Ir and RhA simple pseudopotential model is proposed, which allows the phonon spectra and temperature dependence of the lattice heat capacity of Ir and Rh be described with a high enough accuracy. A careful…M. I. Katsnelson, I. I. Naumov, A. V. Trefilov et al.·Oct 17, 1997SaveLearn
Motion in Periodic PotentialsWe consider motion in a periodic potential in a classical, quantum, and semiclassical context. Various results on the distribution of asymptotic velocities are proven.J. Asch, A. Knauf·Oct 16, 1997SaveLearn
A projection method for statics and dynamics of lattice spin systemsA method based on Monte Carlo sampling of the probability flows projected onto the subspace of one or more slow variables is proposed for investigation of dynamic and static properties of lattice…M. Kolesik, M. A. Novotny, P. A. Rikvold·Oct 15, 1997SaveLearn
First principles calculations of monolayer compressibilitiesWe perform high quality, first principles calculations of the properties of Pb and Tl isolated monolayers. Among these, we consider the equilibrium lattice constant, the two dimensional…C. Sanchez, E. P. M. Leiva·Oct 15, 1997SaveLearn
Density Profiles, Casimir Amplitudes and Critical Exponents in the Two Dimensional Potts Model: A Density Matrix Renormalization StudyWe use the density matrix renormalization group (DMRG) to perform a detailed study of the critical properties of the two dimensional Q state Potts model, including the magnetization and…Enrico Carlon, Ferenc Igloi·Oct 15, 1997SaveLearn
Damping of low-energy excitations of a trapped Bose condensate at finite temperaturesWe present the theory of damping of low-energy excitations of a trapped Bose condensate at finite temperatures, where the damping is provided by the interaction of these excitations with the thermal…P. O. Fedichev, G. V. Shlyapnikov, J. T. M. Walraven·Oct 14, 1997SaveLearn
Damping of Hydrodynamic Modes in a Trapped Bose Gas above the Bose-Einstein Transition TemperatureWe calculate the damping of low-lying collective modes of a trapped Bose gas in the hydrodynamic regime, and show that this comes solely from the shear viscosity, since the contributions from bulk…G. M. Kavoulakis, C. J. Pethick, H. Smith·Oct 14, 1997SaveLearn
Kinetics, Hydrodynamics and Stochastodynamics of Cellular Structure CoarseningFor the first time the phenomenon of cellular structure coarsening are consistently analysed from the positions of kinetic, hydrodynamic and stochastodynamic theories of nonequilibrium statistical…S. B. Goryachev·Oct 14, 1997SaveLearn
Magneto-electrodynamics at high frequencies in the antiferromagnetic and superconducting states of DyNi2B2CWe report the observation of novel behaviour in the radio frequency (rf) and microwave response of DyNi2B2C over a wide range of temperature (T) and magnetic field (H) in the antiferromagnetic…Durga P. Choudhury, H. Srikanth, S. Sridhar et al.·Oct 14, 1997SaveLearn
Quantum state of two trapped Bose-Einstein condensates with a Josephson couplingWe consider the precise quantum state of two trapped, coupled Bose Einstein condensates in the two-mode approximation. We seek a representation of the state in terms of a Wigner-like distribution on…M. J. Steel, M. J. Collett·Oct 14, 1997SaveLearn
Quantum Fractal EigenstatesWe study quantum chaos in open dynamical systems and show that it is characterized by quantum fractal eigenstates located on the underlying classical strange repeller. The states with longest life…Giulio Casati, Giulio Maspero, Dima L. Shepelyansky·Oct 13, 1997SaveLearn
Optimal Energy Estimation in Path-Integral Monte Carlo SimulationsWe investigate the properties of two standard energy estimators used in path-integral Monte Carlo simulations. By disentangling the variance of the estimators and their autocorrelation times we…Wolfhard Janke, Tilman Sauer·Oct 13, 1997SaveLearn
Incremental expansions for Hubbard-Peierls systemsThe ground state energies of infinite half-filled Hubbard-Peierls chains are investigated combining incremental expansion with exact diagonalization of finite chain segments. The ground state energy…Jiri Malek, Konstantin Kladko, Sergej Flach·Oct 12, 1997SaveLearn
Test of Guttmann and Enting's conjecture in the eight-vertex modelWe investigate the analyticity property of the partially resummed series expansion(PRSE) of the partition function for the eight-vertex model. Developing a graphical technique, we have obtained a…Hiroshi Tsukahara, Takeo Inami·Oct 11, 1997SaveLearn
Models of stress fluctuations in granular mediaWe investigate in detail two models describing how stresses propagate and fluctuate in granular media. The first one is a scalar model where only the vertical component of the stress tensor is…P. Claudin, J. -P. Bouchaud, M. E. Cates et al.·Oct 10, 1997SaveLearn
Kinetic description of diffusion-limited reactions in random catalytic mediaWe study the kinetics of bimolecular, catalytically-activated reactions (CARs) in d-dimensions. The elementary reaction act between reactants takes place only when these meet in the vicinity of a…G. Oshanin, A. Blumen·Oct 10, 1997SaveLearn
Critical phenomena at perfect and non-perfect surfacesThe effect of imperfections on surface critical properties is studied for Ising models with nearest-neighbour ferromagnetic couplings on simple cubic lattices. In particular, results of Monte Carlo…M. Pleimling, W. Selke·Oct 10, 1997SaveLearn
Enhancement of Quantum Tunneling for Excited States in Ferromagnetic ParticlesA formula suitable for a quantitative evaluation of the tunneling effect in a ferromagnetic particle is derived with the help of the instanton method. The tunneling between n-th degenerate states of…J. -Q. Liang, Y. -B. Zhang, H. J. W. Mueller-Kirsten et al.·Oct 9, 1997SaveLearn
Average stresses and force fluctuations in non-cohesive granular materialsA lattice model is presented for investigating the fluctuations in static granular materials under gravitationally induced stress. The model is similar in spirit to the scalar q-model of Coppersmith…Joshua E. S. Socolar·Oct 9, 1997SaveLearn
Anisotropic GaAs island phase grown on flat GaP: spontaneously formed quantum wire arrayA dense phase of GaAs wires forms in the early stages of strained growth on GaP,assembling from elongated Stranski-Krastanow islands. The electron diffraction during growth is consistent with long,…B. Jonas Ohlsson, Mark S. Miller, Mats-Erik Pistol·Oct 9, 1997SaveLearn
Transition to self-organized criticality in a rice-pile modeThe self-organized critical state is characterized by a power law distribution of cluster sizes and other properties. However experiments with sand and rice piles reveal distributions of avalanche…A. Vazquez, O. Sotolongo-Costa·Oct 8, 1997SaveLearn
Quantum Decoherence in Disordered Mesoscopic SystemsWe point out that the low temperature saturation of the electron phase decoherence time in a disordered conductor can be explained within the existing theory of weak localization provided the effect…Dmitrii S. Golubev, Andrei D. Zaikin·Oct 8, 1997SaveLearn
Monte-Carlo simulations of the violation of the fluctuation-dissipation theorem in domain growth processesNumerical simulations of various domain growth systems are reported, in order to compute the parameter describing the violation of fluctuation dissipation theorem (FDT) in aging phenomena. We compute…A. Barrat·Oct 8, 1997SaveLearn
Sandpile Model for Relaxation in Complex SystemsThe relaxation in complex systems is in general nonexponential. After an initial rapid decay the system relax slowly following a long time tail. In the present paper a sandpile modelation of the…A. Vazquez, O. Sotolongo-Costa, F. Brouers·Oct 7, 1997SaveLearn