Effective Gauge Theories, The Renormalization Group, and High-Temperature SuperconductivityThese lectures serve as an introduction to the renormalization group approach to effective field theories, with emphasis on systems with a Fermi surface. For such systems, demanding appropriate…A. Campbell-Smith, N. E. Mavromatos·Feb 18, 1999SaveLearn
Punctuated vortex coalescence and discrete scale invariance in two-dimensional turbulenceWe present experimental evidence and theoretical arguments showing that the time-evolution of freely decaying 2-d turbulence is governed by a discrete time scale invariance rather than a…Anders Johansen, Didier Sornette, Adam Espe Hansen·Feb 17, 1999SaveLearn
3D Anderson transition for two electrons in 2DIt is shown that the Coulomb interaction can lead to delocalization of two electron states in two-dimensional (2D) disordered potential in a way similar to the Anderson transition in three dimensions…D. L. Shepelyansky·Feb 17, 1999SaveLearn
Renormalization group study of one-dimensional systems with roughening transitionsA recently introduced real space renormalization group technique, developed for the analysis of processes in the Kardar-Parisi-Zhang universality class, is generalized and tested by applying it to a…G. Bianconi, M. A. Munoz, A. Gabrielli et al.·Feb 17, 1999SaveLearn
Spin-ordering in S = 1 anisotropic Heisenberg models with nondiagonal spin exchangeThe properties of S = 1 anisotropic Heisenberg models with nondiagonal exchange between axial and planar spin components are investigated using Monte Carlo techniques. The quantum nature is taken…M. Pleimling·Feb 17, 1999SaveLearn
Optical Conductivity of the Two-Dimensional Hubbard ModelCharge dynamics of the two-dimensional Hubbard model is investigated. Lancz os-diagonalization results for the optical conductivity and the Drude weight of this model are presented. Near…Hiroki Nakano, Masatoshi Imada·Feb 17, 1999SaveLearn
Comment on ``Mechanisms of synchronization and pattern formation in a lattice of pulse-coupled oscillators'' by Diaz-Guilera et al., Phys. Rev. E 57, 3820 (1998)In a recent paper, Diaz-Guilera et al. [Phys. Rev. E 57, 3820 (1998)] analyze the mechanisms of synchronization and pattern formation in a lattice of pulse-coupled oscillators. In essence, their…J. M. G. Vilar·Feb 17, 1999SaveLearn
Enhancement of de Haas-van Alphen Oscillation due to Spin in the Magnetic Breakdown SystemThe effects of the Zeeman term on the de Haas-van Alphen oscillation is studied in the magnetic breakdown system. We find that the amplitude of the oscillation with the frequencies of fβ + fα and…Keita Kishigi, Yasumasa Hasegawa, Mitake Miyazaki·Feb 16, 1999SaveLearn
Green Function Monte Carlo with Stochastic Reconfiguration: an effective remedy for the sign problem diseaseA recent technique, proposed to alleviate the ``sign problem disease'', is discussed in details. As well known the ground state of a given Hamiltonian H can be obtained by applying the…S. Sorella, L. Capriotti·Feb 15, 1999SaveLearn
Periodic Vortex Structures in Superfluid 3He-AWe discuss the general properties of periodic vortex arrangements in rotating superfluids. The different possible structures are classified according to the symmetry space-groups and the circulation…J. M. Karimaki, E. V. Thuneberg·Feb 15, 1999SaveLearn
AC Response of Thin Film Superconductors at Various Temperatures and Magnetic FieldsThe basic theory of the linear and nonlinear ac susceptibilities of type-II superconductors is outlined for various geometries, e.g. circular and elliptic disks, rings, and strips of thin films or of…Ernst Helmut Brandt·Feb 12, 1999SaveLearn
Analytic Solution for the Critical State in Superconducting Elliptic FilmsA thin superconductor platelet with elliptic shape in a perpendicular magnetic field is considered. Using a method originally applied to circular disks, we obtain an approximate analytic solution for…Grigorii P. Mikitik, Ernst Helmut Brandt·Feb 12, 1999SaveLearn
Ground state of a homogeneous Bose gas: a diffusion Monte Carlo calculationWe use a diffusion Monte Carlo method to calculate the lowest energy state of a uniform gas of bosons interacting through different model potentials, both strictly repulsive and with an attractive…S. Giorgini, J. Boronat, J. Casulleras·Feb 12, 1999SaveLearn
Interfacial adsorption in two-dimensional Potts modelsThe interfacial adsorption W at the first-order transition in two-dimensional q-state Potts models is studied. In particular, findings of Monte Carlo simulations and of density-matrix renormalization…E. Carlon, F. Igloi, W. Selke et al.·Feb 12, 1999SaveLearn
Comment on "Isotope Dependence of the Spin Gap in YBa2Cu4O8 as determined by Cu NQR Relaxation"Comment is made on the isotope dependence of the spin gap in YBa2Cu4O8.J. L. Tallon, G. V. M. Williams, D. J. Pringle·Feb 12, 1999SaveLearn
Chaos and energy spreading for time-Dependent Hamiltonians, and the various Regimes in the theory of Quantum DissipationWe make the first steps towards a generic theory for energy spreading and quantum dissipation. The Wall formula for the calculation of friction in nuclear physics and the Drude formula for the…Doron Cohen·Feb 11, 1999SaveLearn
The Surface of a Bose-Einstein Condensed Atomic CloudWe investigate the structure and collective modes of a planar surface of a trapped Bose-Einstein condensed gas at zero temperature. In the long-wavelength limit we find a mode similar to the gravity…U. Al Khawaja, C. J. Pethick, H. Smith·Feb 11, 1999SaveLearn
A two-dimensional interacting system obeying Fractional Exclusion StatisticsWe consider N fermions in a two-dimensional harmonic oscillator potential interacting with a very short-range repulsive pair-wise potential. The ground-state energy of this system is obtained by…M. K. Srivastava, R. K. Bhaduri, J. Law et al.·Feb 11, 1999SaveLearn
Evolution of a Bose-Einstein condensate of neutral atoms --- A field theoretical approachThe particle distribution in a Bose condensate under the trapping potential and its time evolution after switching off the trapping potential suddenly are calculated. We investigate the problem from…Koichi Nakamura, Yoshiya Yamanaka·Feb 11, 1999SaveLearn
Theory of strong outcoupling from Bose-Einstein condensatesWe study the dynamics of a magnetically trapped Bose-Einstein condensate in the presence of an external electromagnetic field coupling trapped, untrapped and antitrapped Zeeman sublevels. For large…Robert Graham, Dan F. Walls·Feb 10, 1999SaveLearn
Universal amplitude ratios in the 2D four state Potts modelWe present a Monte Carlo study of various universal amplitude ratios of the two dimensional q=4 Potts model. We simulated the model close to criticality in both phases taking care to keep the…Michele Caselle, Roberto Tateo, Stefano Vinti·Feb 10, 1999SaveLearn
Hierarchy of equations of motion for nonlinear coherent excitations applied to magnetic vorticesStarting from a travelling wave ansatz we show successively that the shape of a nonlinear excitation generally depends also on the 1st, 2nd, ... time derivative of the position X of the excitation.…F. G. Mertens, H. -J. Schnitzer, A. R. Bishop·Feb 10, 1999SaveLearn
Low Temperature Static and Dynamic Behavior of the Two-Dimensional Easy-Axis Heisenberg ModelWe apply the self-consistent harmonic approximation (SCHA) to study static and dynamic properties of the two-dimensional classical Heisenberg model with easy-axis anisotropy. The static properties…M. E. Gouvea, G. M. Wysin, S. A. Leonel et al.·Feb 10, 1999SaveLearn
Noise-induced switching between vortex states with different polarization in classical two-dimensional easy-plane magnetsIn the 2-dimensional anisotropic Heisenberg model with XY-symmetry there are non-planar vortices which exhibit a localized structure of the z-components of the spins around the vortex center. We…Y. Gaididei, T. Kamppeter, F. G. Mertens et al.·Feb 10, 1999SaveLearn
Stochastic vortex dynamics in two-dimensional easy-plane ferromagnets: Multiplicative versus additive noiseWe study how thermal fluctuations affect the dynamics of vortices in the two-dimensional classical, ferromagnetic, anisotropic Heisenberg model depending on their additive or multiplicative…Till Kamppeter, Franz G. Mertens, Esteban Moro et al.·Feb 10, 1999SaveLearn