Quantum Evaporation from Superfluid Helium at Normal IncidenceWe study the scattering of atoms, rotons and phonons at the free surface of 4He at normal incidence and calculate the evaporation, condensation and reflection probabilities. Assuming elastic…F. Dalfovo, M. Guilleumas, A. Lastri et al.·Dec 4, 1996SaveLearn
Quasi-localized states in disordered metals and non-analyticity of the level curvature distribution functionIt is shown that the quasi-localized states in weakly disordered systems can lead to the non-analytical distribution of level curvatures. In 2D systems the distribution function P(K) has a branching…V. E. Kravtsov, I. V. Yurkevich·Dec 3, 1996SaveLearn
One-dimensional spin-liquid without magnon excitationsIt is shown that a sufficiently strong four-spin interaction in the spin-1/2 spin ladder can cause dimerization. Such interaction can be generated either by phonons or (in the doped state) by the…A. A. Nersesyan, A. M. Tsvelik·Dec 2, 1996SaveLearn
A cluster heat bath method on a quasi-onedimensional Ising modelWe have proposed a cluster heat bath(CHB) method of a quasi-one dimensional Ising model and demonstrated that it reproduces the exact results of the two dimensional Ising model with axially…Osamu Koseki, Fumitaka Matsubara·Dec 2, 1996SaveLearn
Evolution of wave packets in quasi-1D and 1D random media: diffusion versus localizationWe study numerically the evolution of wavepackets in quasi one-dimensional random systems described by a tight-binding Hamiltonian with long-range random interactions. Results are presented for the…F. M. Izrailev, T. Kottos, A. Politi et al.·Dec 2, 1996SaveLearn
Symmetrized DMRG studies of the properties of Low-lying states of Poly-para-phenylene (PPP) systemWe report the symmetrized density matrix renormalization group (DMRG) study of neutral and doped oligomers of PPP system within an extended Hubbard model. Model parameters are determined by comparing…Y. Anusooya, Swapan K. Pati, S. Ramasesha·Nov 30, 1996SaveLearn
Two interacting quasiparticles above the Fermi seaWe study numerically the interaction and disorder effects for two quasiparticles in two and three dimensions. The dependence of the interaction-induced Breit-Wigner width on the excitation energy…Ph. Jacquod, D. L. Shepelyansky·Nov 29, 1996SaveLearn
Periodic generation and propagation of traveling fronts in dc voltage biased semiconductor superlatticesThe continuum limit of a recently-proposed model for charge transport in resonant-tunneling semiconductor superlattices is analyzed. It is described by a nonlinear hyperbolic integrodifferential…Luis L. Bonilla, Manuel Kindelan, Miguel Moscoso et al.·Nov 28, 1996SaveLearn
The Anderson Model as a Matrix ModelIn this paper we describe a strategy to study the Anderson model of an electron in a random potential at weak coupling by a renormalization group analysis. There is an interesting technical analogy…J. Magnen, G. Poirot, V. Rivasseau·Nov 28, 1996SaveLearn
Coherent noise, scale invariance and intermittency in large systemsWe introduce a new class of models in which a large number of "agents" organize under the influence of an externally imposed coherent noise. The model shows reorganization events whose size…Kim Sneppen, M. E. J. Newman·Nov 28, 1996SaveLearn
Muon Spin Relaxation Investigation of the Spin Dynamics of Geometrically Frustrated Antiferromagnets Y2Mo2O7 and Tb2Mo2O7 Static Critical Behavior of the Spin-FreezingThe spin dynamics of geometrically frustrated pyrochlore antiferromagnets Y2Mo2O7 and Tb2Mo2O7 have been investigated using muon spin relaxation. A dramatic slowing down of the moment fluctuations…S. R. Dunsiger, R. F. Kiefl, K. H. Chow et al.·Nov 27, 1996SaveLearn
Higher Order Correlations in Quantum Chaotic SpectraThe statistical properties of the quantum chaotic spectra have been studied, so far, only up to the second order correlation effects. The numerical as well as the analytical evidence that random…Pragya Shukla·Nov 27, 1996SaveLearn
Universal Wide Correlators in Non-Gaussian Orthogonal, Unitary and Symplectic Random Matrix EnsemblesWe calculate wide distance connected correlators in non-gaussian orthogonal, unitary and symplectic random matrix ensembles by solving the loop equation in the 1/N-expansion. The multi-level…Chigak Itoi·Nov 27, 1996SaveLearn
Study of CO Oxidation over Ru(0001) at High Gas PressuresExperiments performed at high gas partial pressures have demonstrated that the kinetics of the CO oxidation reaction at Ru(0001) is different and somewhat anomalous compared to that over other…C. Stampfl, M. Scheffler·Nov 27, 1996SaveLearn
Collapses and revivals in the interference between two Bose-Einstein condensates formed in small atomic samplesWe investigate the quantum interference between two Bose-Einstein condensates formed in small atomic samples composed of a few thousand atoms both by imposing Bose broken gauge symmetry from the…E. M. Wright, T. Wong, M. J. Collett et al.·Nov 27, 1996SaveLearn
Quantum Versus Mean Field Behavior of Normal Modes of a Bose-Einstein Condensate in a Magnetic TrapQuantum evolution of a collective mode of a Bose-Einstein condensate containing a finite number N of particles shows the phenomena of collapses and revivals. The characteristic collapse time depends…A. B. Kuklov, N. Chencinski, A. M. Levine et al.·Nov 26, 1996SaveLearn
Microcanonical vs. canonical thermodynamicsThe microcanonical ensemble is in important physical situations different from the canonical one even in the thermodynamic limit. In contrast to the canonical ensemble it does not suppress spatially…D. H. E. Gross, M. E. Madjet·Nov 25, 1996SaveLearn
Morphological Instabilities in a growing Yeast Colony: Experiment and TheoryWe study the growth of colonies of the yeast Pichia membranaefaciens on agarose film. The growth conditions are controlled in a setup where nutrients are supplied through an agarose film suspended…Thomas Sams, Kim Sneppen, Mogens H. Jensen et al.·Nov 25, 1996SaveLearn
Nonequilibrium Phase Transition and 'Specific-heat' singularity in the kinetic Ising model: A Monte Carlo StudyThe nonequilibrium phase transition has been studied by Monte Carlo simulation in a ferromagnetically interacting (nearest neighbour) kinetic Ising model in presence of a sinusoidally oscillating…Muktish Acharyya·Nov 23, 1996SaveLearn
Dynamic Response of Ising System to a Pulsed FieldThe dynamical response to a pulsed magnetic field has been studied here both using Monte Carlo simulation and by solving numerically the meanfield dynamical equation of motion for the Ising model.…M. Acharyya, J. K. Bhattacharjee, B. K. Chakrabarti·Nov 23, 1996SaveLearn
Nonequilibrium Phase Transition in the Kinetic Ising model: Critical Slowing Down and Specific-heat SingularityThe nonequilibrium dynamic phase transition, in the kinetic Ising model in presence of an oscillating magnetic field, has been studied both by Monte Carlo simulation and by solving numerically the…Muktish Acharyya·Nov 23, 1996SaveLearn
Internal Forces and the Magnetoconductivity of a Nondegenerate 2D Electron FluidThe forces on individual electrons in an unscreened nondegenerate electron fluid, due to electron density fluctuations, have been calculated using Monte Carlo simulations and determined…P. Fozooni, P. J. Richardson, M. J. Lea et al.·Nov 23, 1996SaveLearn
Local susceptibilities in semi-infinite antiferromagnet chains: elementary perspectivesUsing conformal field theory methods Eggert and Affleck have shown that the semi-infinite S=1/2 Heisenberg antiferromagnetic chain exhibits a remarkable alternation in its local response to a uniform…Martin P. Gelfand, Elisabeth F. Gloeggler·Nov 22, 1996SaveLearn
Multiple Rayleigh scattering of electromagnetic wavesMultiple scattering of polarised electromagnetic waves in diffusive media is investigated by means of radiative transfer theory. The method becomes exact in several situations of interest, such as a…E. Amic, J. M. Luck, Th. M. Nieuwenhuizen·Nov 22, 1996SaveLearn
An Extension of Phenomenological Renormalization MethodWe present an extension of the so-called cumulant crossing method which is used for determination of critical point in Monte Carlo simulations.The new method uses linear combination of several…M. Itakura·Nov 22, 1996SaveLearn