Melting of a colloidal crystalA melting transition for a system of hard spheres interacting by a repulsive Yukawa potential of DLVO form is studied. To find the location of the phase boundary, we propose a simple theory to…P. S. Kuhn, A. Diehl, Y. Levin et al.·May 21, 1997SaveLearn
A ``Tetris''-like model for the Compaction of Dry Granular MediaWe propose a two-dimensional geometrical model, based on the concept of geometrical frustration, conceived for the study of compaction in granular media. The dynamics exhibits an interesting inverse…E. Caglioti, V. Loreto, H. J. Herrmann et al.·May 20, 1997SaveLearn
Numerical Study of the Incommensurate Phase in Spin-Peierls SystemsWe analyze several properties of the lattice solitons in the incommensurate phase of spin-Peierls systems using exact diagonalization and quantum Monte Carlo. These systems are modelled by an…A. E. Feiguin, J. A. Riera, A. Dobry et al.·May 20, 1997SaveLearn
Spin-S bilayer Heisenberg models: Mean-field arguments and numerical calculationsSpin-S bilayer Heisenberg models (nearest-neighbor square lattice antiferromagnets in each layer, with antiferromagnetic interlayer couplings) are treated using dimer mean-field theory for general S…Martin P. Gelfand, Zheng Weihong, C. J. Hamer et al.·May 20, 1997SaveLearn
Near Critical States of Random Dirac FermionsRandom Dirac fermions in a two-dimensional space are studied numerically. We realize them on a square lattice using the π-flux model with random hopping. The system preserves two symmetries, the…Yoshifumi Morita, Yasuhiro Hatsugai·May 20, 1997SaveLearn
Folding and Misfolding of Designed Heteropolymer Chains with MutationsWe study the impact of mutations (changes in amino acid sequence) on the thermodynamics of simple protein-like heteropolymers consisting of N monomers, representing the amino acid sequence. The…G. Tiana, R. A. Broglia, H. E. Roman et al.·May 19, 1997SaveLearn
Coulomb Drag at the Onset of Anderson InsulatorsIt is shown that the Coulomb drag between two identical layers in the Anderson insulting state indicates a striking difference between the Mott and Efros-Shklovskii (ES) insulators. In the former,…Efrat Shimshoni·May 18, 1997SaveLearn
Competition between plaquette and dimer phases in Heisenberg chainsWe consider a class of one-dimensional Heisenberg spin models (plaquette chains) related to the recently found 1/5-depleted square-lattice Heisenberg system CaV4O9. A number of exact and…N. B. Ivanov, J. Richter·May 16, 1997SaveLearn
Stability of Uniform Shear FlowThe stability of idealized shear flow at long wavelengths is studied in detail. A hydrodynamic analysis at the level of the Navier-Stokes equation for small shear rates is given to identify the…Jose M. Montanero, Andres Santos, Mirim Lee et al.·May 15, 1997SaveLearn
Density of Topological Defects After a QuenchWe present results of numerical studies of the Landau-Ginzburg dynamics of the order parameter in one-dimensional models inspired by the condensed matter analogues of cosmological phase transitions.…Pablo Laguna, Wojciech Zurek·May 14, 1997SaveLearn
Variable-phase method and Levinson's theorem in two dimensions: Application to a screened Coulomb potentialThe variable-phase approach is applied to scattering and bound states in an attractive Coulomb potential, statically screened by a two-dimensional (2D) electron gas. A 2D formulation of…M. E. Portnoi, I. Galbraith·May 14, 1997SaveLearn
Two-Fluid Hydrodynamics for a Trapped Weakly-Interacting Bose GasWe derive the coupled equations of motion for the condensate (superfluid) and non-condensate (normal fluid) degrees of freedom in a trapped Bose gas at finite temperatures. Our results are based on…E. Zaremba, A. Griffin, T. Nikuni·May 14, 1997SaveLearn
Semiclassical wave functions and energy levels of Bose-condensed gases in spherically symmetric trapsThe WKB-approximation for the Bogoliubov-equations of the quasi-particle excitations in Bose-gases with condensate is worked out in the case of spherically symmetric trap potentials on the basis of…Andr'as Csord'as, Robert Graham, P'eter Sz'epfalusy·May 14, 1997SaveLearn
Soliton Confinement and the Excitation Spectrum of Spin-Peierls AntiferromagnetsThe excitation spectrum of spin-Peierls antiferromagnets is discussed taking into acount phonon dynamics but treating inter-chain elastic couplings in mean field theory. This gives a ladder of…Ian Affleck·May 14, 1997SaveLearn
Clean and As-covered zinc-blende GaN (001) surfaces: Novel surface structures and surfactant behaviorWe have investigated clean and As-covered zinc-blende GaN (001) surfaces, employing first-principles total-energy calculations. For clean GaN surfaces our results reveal a novel surface structure…Joerg Neugebauer, Tosja Zywietz, Matthias Scheffler et al.·May 13, 1997SaveLearn
Spin-Peierls vs. Peierls distortions in a family of conjugated PolymersDistortions in a family of conjugated polymers are studied within two complementary approaches, i.e. within a many-body Valence Bond (VB) approach using a transfer matrix technique to treat the…M. A. Garcia-Bach, R. Valenti, D. J. Klein·May 13, 1997SaveLearn
Orthorhombicity mixing of s- and d- gap components in YBa2Cu3O7 without involving the chainsMomentum decoupling develops when forward scattering dominates the pairing interaction and implies tendency for decorrelation between the physical behavior in the various regions of the Fermi…Georgios Varelogiannis·May 13, 1997SaveLearn
Doping Dependence of the Magnetic Resonance Peak in YBa2 Cu3 O6+xWe report inelastic neutron scattering experiments on the doping dependence of the energy and spectral weight of the sharp magnetic resonance peak in YBa2 Cu3 O6+x. These measurements also shed…B. Keimer, H. F. Fong, S. H. Lee et al.·May 12, 1997SaveLearn
Molecular-field approach to the spin-Peierls transition in CuGeO3We present a theory for the spin-Peierls transition in CuGeO3. We map the elementary excitations of the dimerized chain (solitons) on an effective Ising model. Inter-chain coupling (or phonons) then…Ralph Werner, Claudius Gros·May 12, 1997SaveLearn
On Experimental Evidence of Uncertainty of Quantized Electromagnetic Potential from QHEIt is shown that the observed potential drops on QHE samples can be considered as a realization of uncertainty relation for the quantized two dimensional electromagnetic potential.F. Ghaboussi·May 12, 1997SaveLearn
Localization Transitions from Free Random VariablesWe motivate and use the concept of free random variables for the studies of the de-pinning transition of flux lines in superconductors as recently discussed by Hatano and Nelson. We derive analytical…Romuald A. Janik, Maciej A. Nowak, Gabor Papp et al.·May 11, 1997SaveLearn
Toward semiclassical theory of quantum level correlations of generic chaotic systemsIn the present work we study the two-point correlation function R(ε) of the quantum mechanical spectrum of a classically chaotic system. Recently this quantity has been computed for chaotic and for…Daniel L. Miller·May 10, 1997SaveLearn
The two-point correlation function of three-dimensional O(N) models: critical limit and anisotropyIn three-dimensional O(N) models, we investigate the low-momentum behavior of the two-point Green's function G(x) in the critical region of the symmetric phase. We consider physical systems whose…M. Campostrini, A. Pelissetto, P. Rossi et al.·May 9, 1997SaveLearn
Quantum Scattering Theoretical Description of Thermodynamical Transport PhenomenaWe give a method of describing thermodynamical transport phenomena, based on a quantum scattering theoretical approach. We consider a quantum system of particles connected to thermodynamical…Tooru Taniguchi·May 9, 1997SaveLearn
Self Organized Criticality in Digging Myopic Ant ModelWe demonstrate the phenomenon of self organized criticality (SOC) in a simple random walk model described by a random walk of a myopic ant. The ant acts on the underlying lattice aiming at uniform…Prashant M. Gade, M. P. Joy·May 8, 1997SaveLearn