Fermionization and Hubbard ModelsWe introduce a transformation which allows the fermionization of operators of any one-dimensional spin-chain. This fermionization procedure is independent of any eventual integrable structure and is…P. Dargis, Z. Maassarani·Jun 17, 1998SaveLearn
A Wannier function based ab initio Hartree-Fock approach extended to polymers: applications to the LiH chain and trans-polyacetyleneA recently proposed ab initio Hartree-Fock approach aimed at directly obtaining the Wannier functions of a crystalline insulator is applied to polymers. The systems considered are the LiH chain and…Alok Shukla, Michael Dolg, Hermann Stoll·Jun 17, 1998SaveLearn
Anharmonicity of flux lattices and thermal fluctuations in layered superconductorsWe study elasticity of a perpendicular flux lattice in a layered superconductor with Josephson coupling between layers. We find that the energy contains ln(flux displacement) terms, so that elastic…T. Ruth Goldin, Baruch Horovitz·Jun 16, 1998SaveLearn
Beyond the binary collision approximation for the large-q response of liquid 4HeWe discuss corrections to the linear response of a many-body system beyond the binary collision approximation. We first derive for smooth pair interactions an exact expression of the response…A. S. Rinat, M. F. Taragin·Jun 16, 1998SaveLearn
Derivative Expansion of One-Loop Effective Energy of Stiff Membranes with TensionWith help of a derivative expansion, the one-loop corrections to the energy functional of a nearly flat, stiff membrane with tension due to thermal fluctuations are calculated in the Monge…M. E. S. Borelli, H. Kleinert, Adriaan M. J. Schakel·Jun 15, 1998SaveLearn
Impurity effective mass in superfluid 4HeThe system of bose liquid + impurity is considered. The energy spectrum as well as effective mass of impurity is calculated. For the case of the 3He atom in superfluid 4He numerical…I. O. Vakarchuk, V. V. Babin·Jun 15, 1998SaveLearn
Mean field theory of critical coupled map latticesWe study the single-site approximation of the Perron-Frobenius equation for a coupled map lattice exhibiting a phase transition at a critical value gc of the coupling constant. We found that the…Stefano Lepri, Wolfram Just·Jun 15, 1998SaveLearn
Edge critical behavior at the surface transition of Ising magnetsUsing Monte Carlo techniques, Ising models with ferromagnetic nearest-neighbor interactions on a simple cubic lattice are studied. At the surface transition, the critical exponent β2 of the edge…M. Pleimling, W. Selke·Jun 15, 1998SaveLearn
Superconducting proximity effect in a mesoscopic ferromagnetic wireWe present an experimental study of the transport properties of a ferromagnetic metallic wire (Co) in metallic contact with a superconductor (Al). As the temperature is decreased below the Al…M. Giroud, H. Courtois, K. Hasselbach et al.·Jun 12, 1998SaveLearn
Edge Electron GasThe uniform electron gas, the traditional starting point for density-based many-body theories of inhomogeneous systems, is inappropriate near electronic edges. In its place we put forward the…Walter Kohn, Ann E. Mattsson·Jun 12, 1998SaveLearn
Phase conjugation of trapped Bose-Einstein condensatesWe consider a multicomponent atomic Bose-Einstein condensate optically trapped in a far-off resonant dipole trap. Drawing an analogy with the optical situation, we show that this system can be…Elena V. Goldstein, Pierre Meystre·Jun 12, 1998SaveLearn
The Chaotic Properties of the Q-state Potts Model on the Bethe Lattice:Q<2The Q- state Potts model on the Bethe lattice is investigated for Q<2. The magnetization of this model exhibits a complicated behavior including both the period doubling bifurcation and chaos. The…N. S. Ananikian, S. K. Dallakian, B. Hu·Jun 11, 1998SaveLearn
Density of hedgehogs just after a quenchDensity of vortices and monopoles after a rapid pressure quench is predicted. Critical exponents are worked out in overdamped and underdamped limits.Jacek Dziarmaga·Jun 11, 1998SaveLearn
Interface states in junctions of two semiconductors with intersecting dispersion curvesA novel type of shallow interface state in junctions of two semiconductors without band inversion is identified within the envelope function approximation, using the two-band model. It occurs in…A. V. Kolesnikov, R. Lipperheide, A. P. Silin et al.·Jun 10, 1998SaveLearn
Fractional charge in transport through a 1D correlated insulator of finite lengthTransport through a one channel wire of length L confined between two leads is examined when the 1D electron system has an energy gap 2M: M > TL vc/L induced by the interaction in…Vadim Ponomarenko, Naoto Nagaosa·Jun 10, 1998SaveLearn
Transmission and reflection in a perfectly amplifying and absorbing mediumWe study transmission and reflection properties of a perfectly amplifying as well as absorbing medium analytically by using the tight binding equation. Different expressions for transmittance and…P. K. Datta·Jun 10, 1998SaveLearn
Comment on the paper ``Bound States in the One-dimensional Hubbard Model''We comment on the preprint cond-mat/9805103 by D. Braak and N. Andrei BrAn98. We point out that the ``new'' Bethe Ansatz equations presented in BrAn98 are identical to the Bethe…F. H. L. Eßler, F. Göhmann, V. E. Korepin·Jun 9, 1998SaveLearn
Exciton condensates in semiconductor quantum wells emit coherent lightWe show that a quasi-two dimensional condensate of optically active excitons emits coherent light even in the absence of population inversion. This allows an unambiguous and clear experimental…J. Fernandez-Rossier, C. Tejedor, R. Merlin·Jun 9, 1998SaveLearn
From Neurons to Brain: Adaptive Self-Wiring of NeuronsDuring embryonic morpho-genesis, a collection of individual neurons turns into a functioning network with unique capabilities. Only recently has this most staggering example of emergent process in…Ronen Segev, Eshel Ben-Jacob·Jun 9, 1998SaveLearn
Hydrodynamic modes and pulse propagation in a cylindrical Bose gas above the Bose-Einstein transitionWe study hydrodynamic oscillations of a cylindrical Bose gas above the Bose-Einstein transition temperature using the hydrodynamic equations derived by Griffin, Wu and Stringari. This extends recent…T. Nikuni, A. Griffin·Jun 9, 1998SaveLearn
Exact Solution of a Electron System Combining Two Different t-J ModelsA new strongly correlated electron model is presented. This is formed by two types of sites: one where double occupancy is forbidden, as in the t-J model, and the other where double occupancy is…J. Abad, M. Ríos·Jun 8, 1998SaveLearn
Spin and density longitudinal response of quantum dots in time-dependent local-spin-density approximationThe longitudinal dipole response of a quantum dot has been calculated in the far-infrared regime using local spin density functional theory. We have studied the coupling between the collective spin…Ll. Serra, M. Barranco, A. Emperador et al.·Jun 8, 1998SaveLearn
Elements for a Theory of Financial RisksEstimating and controlling large risks has become one of the main concern of financial institutions. This requires the development of adequate statistical models and theoretical tools (which go…Jean-Philippe Bouchaud·Jun 8, 1998SaveLearn
Quantum Tunneling and Phase Transitions in Spin Systems with an Applied Magnetic FieldTransitions from classical to quantum behaviour in a spin system with two degenerate ground states separated by twin energy barriers which are asymmetric due to an applied magnetic field are…S. -Y. Lee, H. J. W. Mueller-Kirsten, D. K. Park et al.·Jun 8, 1998SaveLearn
Molecular dynamics in shape space and femtosecond vibrational spectroscopy of metal clustersWe introduce a method of molecular dynamics in shape space aimed at metal clusters. The ionic degrees of freedom are described via a dynamically deformable jellium with inertia parameters derived…Constantine Yannouleas, Uzi Landman·Jun 6, 1998SaveLearn