Comment on "On the TS-Anomaly in Betaine Calcium Chloride Dihydrate"Recently, Hlinka and Ishibashi [J. Phys. Soc. Jpn. 67, 495 (1998)] discussed the TS-anomaly in betaine calcium chloride dihydrate (BCCD) in a Landau-type approach. We comment on the shortcomings…Boris Neubert, Michel Pleimling·May 25, 1998SaveLearn
Spin Dynamics for the t-J ModelThe spin dynamics at the finite temperature for the t-J model in the underdoped and optimal doped regimes is studied within the fermion-spin theory. It is shown that the dynamical spin structure…Zhongbing Huang, Shiping Feng·May 24, 1998SaveLearn
Spin-wave Scattering in the Effective Lagrangian PerspectiveNonrelativistic systems exhibiting collective magnetic behavior are analyzed in the framework of effective Lagrangians. The method, formulating the dynamics in terms of Goldstone bosons, allows to…Christoph P. Hofmann·May 22, 1998SaveLearn
On the driven Frenkel-Kontorova model: II. Chaotic sliding and nonequilibrium melting and freezingThe dynamical behavior of a weakly damped harmonic chain in a spatially periodic potential (Frenkel-Kontorova model) under the subject of an external force is investigated. We show that the chain can…Torsten Strunz, Franz-Josef Elmer·May 22, 1998SaveLearn
On the driven Frenkel-Kontorova model: I. Uniform sliding states and dynamical domains of different particle densitiesThe dynamical behavior of a harmonic chain in a spatially periodic potential (Frenkel-Kontorova model, discrete sine-Gordon equation) under the influence of an external force and a velocity…Torsten Strunz, Franz-Josef Elmer·May 22, 1998SaveLearn
On the theory of vortex quantum tunnelling in the dense Bose superfluid helium IIThe quantum tunnelling and nucleation theory of vortices in helium II is reviewed. Arguments are given that the only reliable method to calculate tunnelling probabilities in this highly correlated,…Uwe R. Fischer·May 21, 1998SaveLearn
Car-Parrinello Molecular Dynamics on excited state surfacesThis paper describes a method to do ab initio molecular dynamics in electronically excited systems within the random phase approximation (RPA). Using a dynamical variational treatment of the RPA…Eric R. Bittner, D. S. Kosov·May 21, 1998SaveLearn
The GW space-time method for the self-energy of large systemsWe present a detailed account of the GW space-time method. The method increases the size of systems whose electronic structure can be studied with a computational implementation of Hedin's GW…M. M. Rieger, L. Steinbeck, I. D. White et al.·May 20, 1998SaveLearn
Creation of gap solitons in Bose-Einstein condensatesWe discuss a method to launch gap soliton-like structures in atomic Bose-Einstein condensates confined in optical traps. Bright vector solitons consisting of a superposition of two hyperfine Zeeman…O. Zobay, E. M. Wright, P. Meystre·May 20, 1998SaveLearn
On the Theory of Magnets with Competing Double Exchange and Superexchange InteractionsIn the CMR materials, ferromagnetic double exchange (DE) presumably coexists with a direct nearest-neighbour antiferromagnetic interaction. We construct a single-site mean field theory that…D. I. Golosov, M. R. Norman, K. Levin·May 19, 1998SaveLearn
Tunneling in Paired Fractional Quantum Hall States: Conductance and Andreev Reflection of Non-AbelionsWe study the edge transport properties of paired fractional quantum Hall (FQH) states--- the Haldane-Rezayi (HR), Moore-Read (Pfaffian) and Halperin (331) states. A table of exponents is given for…Ken-ichiro Imura, Kazusumi Ino·May 19, 1998SaveLearn
Density of Bloch Waves after a QuenchProduction of Bloch waves during a rapid quench is studied by analytical and numerical methods. The density of Bloch waves decays exponentially with the quench time. It also strongly depends on…Jacek Dziarmaga·May 18, 1998SaveLearn
Fermion loops, loop cancellation and density correlations in two dimensional Fermi systemsWe derive explicit results for fermion loops with an arbitrary number of density vertices in two dimensions at zero temperature. The 3-loop is an elementary function of the three external momenta and…Arne Neumayr, Walter Metzner·May 18, 1998SaveLearn
Chaotic enhancement in microwave ionization of Rydberg atomsThe microwave ionization of internally chaotic Rydberg atoms is studied analytically and numerically. The internal chaos is induced by magnetic or static electric fields. This leads to a chaotic…Giuliano Benenti, Giulio Casati, Dima L. Shepelyansky·May 18, 1998SaveLearn
Continuum Field Description of Driven Lattice GasesWe review the critical behaviour of the Driven Lattice Gas (DLG) model. As a result, we obtain a novel Langevin equation for the DLG which depends on the microscopic transition probabilities. We then…F. de los Santos, P. L. Garrido·May 18, 1998SaveLearn
Periodic Instantons and Quantum-Classical Transitions in Spin SystemsSome models allowing explicit calculation of periodic instantons and evaluation of their action are studied with regard to transitions from classical to quantum behaviour as the temperature is…J. -Q. Liang, H. J. W. Mueller-Kirsten, D. K. Park et al.·May 18, 1998SaveLearn
Aging in K1-xLixTa03: a domain growth interpretationThe aging behaviour of the a.c. susceptibility of randomly substituted K1-xLixTa03 crystals reveals marked differences with spin-glasses in that cooling rate effects are very important.…F. Alberici-Kious, J. -P. Bouchaud, L. F Cugliandolo et al.·May 18, 1998SaveLearn
Symmetries and Universality Classes in Conservative Sandpile ModelsThe symmetry properties which determine the critical exponents and universality classes in conservative sandpile models are identified. This is done by introducing a set of models, including all…O. Biham, E. Milshtein, S. Solomon·May 18, 1998SaveLearn
Time and temperature dependent correlation functions of the 1D impenetrable electron gasWe consider the one-dimensional delta-interacting electron gas in the case of infinite repulsion. We use determinant representations to study the long time, large distance asymptotics of correlation…F. Göhmann, A. G. Izergin, V. E. Korepin et al.·May 15, 1998SaveLearn
Gauge Equivalence between Two-Dimensional Heisenberg Ferromagnets with Single-Site Anisotropy and Zakharov EquationsGauge equivalence between the two-dimensional continuous classical Heisenberg ferromagnets(CCHF) of spin 1/2 - the M-I equation with single site anisotropy and the Zakharov equation(ZE) is…R. Myrzakulov·May 15, 1998SaveLearn
The gauge equivalence of the Zakharov equations and (2+1)-dimensional continuous Heisenberg ferromagnetic modelsThe gauge equivalence between the (2+1)-dimensional Zakharov equations and (2+1)-dimensional integrable continuous Heisenberg ferromagnetic model is established. Also their integrable reductions are…R. Myrzakulov·May 15, 1998SaveLearn
Exact four-spinon dynamical correlation function in isotropic Heisenberg modelWe discuss some properties of the exact four-spinon dynamical correlation function S4 in the antiferromagnetic spin 1/2 XXX-model, the expression of which we derived recently. We show that the…A. Abada, A. H. Bougourzi, S. Seba et al.·May 15, 1998SaveLearn
Bose-Einstein Condensate: A Superposition of Macroscopically Squeezed StatesWe study the ground state of a uniform Bose gas at zero temperature in the Hartree-Fock-Bogoliubov (HFB) approximation. We find a solution of the HFB equations which obeys the Hugenholtz-Pines…Patrick Navez·May 14, 1998SaveLearn
Size-Dependent Surface Plasmon Dynamics in Metal NanoparticlesWe study the effect of Coulomb correlations on the ultrafast optical dynamics of small metal particles. We demonstrate that a surface-induced dynamical screening of the electron-electron interactions…T. V. Shahbazyan, I. E. Perakis, J. -Y. Bigot·May 13, 1998SaveLearn
A two--parametric family of asymmetric exclusion processes and its exact solutionA two--parameter family of asymmetric exclusion processes for particles on a one-dimensional lattice is defined. The two parameters of the model control the driving force and an effect which we call…M. Alimohammadi, V. Karimipour, M. Khorrami·May 13, 1998SaveLearn