Transition to an Insulating Phase Induced by Attractive Interactions in the Disordered Three-Dimensional Hubbard ModelWe study numerically the interplay of disorder and attractive interactions for spin-1/2 fermions in the three-dimensional Hubbard model. The results obtained by projector quantum Monte Carlo…Bhargavi Srinivasan, Giuliano Benenti, Dima L. Shepelyansky·Mar 25, 2002SaveLearn
Crossover Temperature from Non-Fermi Liquid to Fermi Liquid Behavior in Two Types of Impurity Kondo ModelNumerical renormalization-group results on entropy of the anisotropic two-channel Kondo model with the band-width cutoff (D) in the presence of a magnetic field (h) are obtained to determine…Satoshi Yotsuhashi, Hideaki Maebashi·Mar 25, 2002SaveLearn
Molecular elasticity and the geometric phaseWe present a method for solving the Worm Like Chain (WLC) model for twisting semiflexible polymers to any desired accuracy. We show that the WLC free energy is a periodic function of the applied…Joseph Samuel, Supurna Sinha·Mar 24, 2002SaveLearn
Resonant Raman Scattering by quadrupolar vibrations of Ni-Ag Core-shell NanoparticlesLow-frequency Raman scattering experiments have been performed on thin films consisting of nickel-silver composite nanoparticles embedded in alumina matrix. It is observed that the Raman scattering…H. Portales, L. Saviot, E. Duval et al.·Mar 22, 2002SaveLearn
About the wording of Fermat`s principle for light propagation in media with negative refraction indexIn this work is elaborated the wording of Fermat`s principle for electromagnetic waves spreading in materials with negative index of refractions (MNR). The recent experiments with such material has…V. G. Veselago·Mar 21, 2002SaveLearn
Self-consistent quantum kinetics of condensate and non-condensate via a coupled equation of motion formalismThis paper extends an earlier quantum kinetics treatment for dilute, weakly-interacting, partially Bose-Einstein condensed gases, presented by the author elsewhere [J. Res. Natl. Inst. Stand.…N. P. Proukakis·Mar 21, 2002SaveLearn
Forbidden activation levels in a non-stationary tunneling processTunneling in the presence of an opaque barrier, part of which varies in time, is investigated numerically and analytically in one dimension. Clearly, due to the varying barrier a tunneling particle…Er'el Granot·Mar 21, 2002SaveLearn
Relaxation, the Boltzmann-Jeans Conjecture and ChaosSlow (logarithmic) relaxation from a highly excited state is studied in a Hamiltonian system with many degrees of freedom. The relaxation time is shown to increase as the exponential of the square…Naoko Nakagawa, Kunihiko Kaneko·Mar 21, 2002SaveLearn
A Dynamic Mechanism of Energy Conversion to a Mechanical WorkWe propose a dynamic mechanism of a molecular machine for energy conversion, by considering a simple model describing the dynamics of two components, the head and the chain. After injection of energy…Naoko Nakagawa, Kunihiko Kaneko·Mar 21, 2002SaveLearn
Basis-dependent dynamics of trapped Bose-Einstein condensates and analogies with semi-classical laser theoryWe present a consistent second order perturbation theory for the lowest-lying condensed modes of very small, weakly-interacting Bose-Einstein condensates in terms of bare particle eigenstates in a…N. P. Proukakis, P. Lambropoulos·Mar 21, 2002SaveLearn
Universality in the Three-Body Problem for 4He AtomsThe two-body scattering length a for 4He atoms is much larger than their effective range rs. As a consequence, low-energy few-body observables have universal characteristics that are independent of…Eric Braaten, H. -W. Hammer·Mar 20, 2002SaveLearn
Correlated Trapped Bosons and the Many-Body Efimov EffectWe study two-body correlations in systems of identical bosons. We use a Faddeev type of decomposition of the wave function where all pairs of particles are treated equally. We focus on a new…O. Sørensen, D. V. Fedorov, A. S. Jensen·Mar 20, 2002SaveLearn
Continuum mesoscale theory inspired by plasticityWe present a simple mesoscale field theory inspired by rate-independent plasticity that reflects the symmetry of the deformation process. We parameterize the plastic deformation by a scalar field…J. P. Sethna, M. Rauscher, J. -P. Bouchaud·Mar 20, 2002SaveLearn
Microscopic nonequilibrium dynamics of an inhomogeneous Bose gas beyond the Born approximationUsing the prescription of the nonequilibrium statistical operator method, we derive a non-Markovian generalization to the kinetic theory described by Walser et al. [Phys. Rev. A 59, 3878…S. G. Bhongale, R. Walser, M. J. Holland·Mar 20, 2002SaveLearn
Space-time evolution of electron cascades in diamondHere we describe model calculations to follow the spatio-temporal evolution of secondary electron cascades in diamond. The band structure of the insulator has been explicitly incorporated into the…Beata Ziaja, Abraham Szoeke, David van der Spoel et al.·Mar 20, 2002SaveLearn
Specific heat and magnetic measurements in Nd0.5Sr0.5MnO3, Nd0.5Ca0.5MnO3 and Ho0.5Ca0.5MnO3 samplesWe studied the magnetization as a function of temperature and magnetic field in the compounds Nd0.5Sr0.5MnO3, Nd0.5Ca0.5MnO3 and Ho0.5Ca0.5MnO3. It allowed us to identify the ferromagnetic,…J. Lopez, O. F. de Lima, P. N. Lisboa-Filho et al.·Mar 19, 2002SaveLearn
Persistent Non-ergodic Fluctuations in Mesoscopic InsulatorsWe give a detailed and rigorous picture of the mesoscopic conductance fluctuations in the deep insulating regime (DIR) within the Nguyen, Spivak and Shklovskii model including spin-orbit coupling…Rafael Rangel, Ernesto Medina·Mar 19, 2002SaveLearn
Magnetic contributions to the low-temperature specific heat of the ferromagnetic insulator: Pr0.8Ca0.2MnO3The Pr(1-xCaxMnO3 system exhibits a ferromagnetic insulating state for the composition range x<0.25. A metallic ferromagnetic state is never realized because of the low hole concentration and the…A. Wahl, V. Hardy, C. Martin et al.·Mar 19, 2002SaveLearn
Non-linear electrical response in a non-charge-ordered manganite: Pr0.8Ca0.2MnO3Up to now, electric field induced non-linear conduction in the Pr(1-x)CaxMnO3 system has been ascribed to a current-induced destabilization of the charge ordered phase. However, for x<0.25, a…S. Mercone, A. Wahl, Ch. Simon et al.·Mar 18, 2002SaveLearn
Non-universal ordering of spin and charge in stripe phasesWe study the interplay of topological excitations in stripe phases: charge dislocations, charge loops, and spin vortices. In two dimensions these defects interact logarithmically on large distances.…Frank Krüger, Stefan Scheidl·Mar 18, 2002SaveLearn
Quantum stochastic theory of phonon scattering between polaritonsQuantum stochastic operator equations are derived for inter-branch exciton and polariton processes caused by acoustic phonon scattering. The use of a fully quantum model combined with these recently…P. Kinsler·Mar 18, 2002SaveLearn
Criticality in self-dual sine-Gordon modelsWe discuss the nature of criticality in the β2 = 2 πN self-dual extention of the sine-Gordon model. This field theory is related to the two-dimensional classical XY model with a N-fold degenerate…P. Lecheminant, A. O. Gogolin, A. A. Nersesyan·Mar 14, 2002SaveLearn
Slow oscillations of magnetoresistance in quasi-two-dimensional metalsSlow oscillations of the interlayer magnetoresistance observed in the layered organic metal β-(BEDT-TTF)2IBr2 are shown to originate from the slight warping of its Fermi surface rather than…M. V. Kartsovnik, P. D. Grigoriev, W. Biberacher et al.·Mar 13, 2002SaveLearn
Linear energy bounds for Heisenberg spin systemsRecently obtained results on linear energy bounds are generalized to arbitrary spin quantum numbers and coupling schemes. Thereby the class of so-called independent magnon states, for which the…H. -J. Schmidt·Mar 13, 2002SaveLearn
Exact enumeration of the Critical States in the Oslo ModelWe determine analytically the number NR(L) of recurrent states in the 1d Oslo model as a function of system size L. The solution $NR(L) =…Alvin Chua, Kim Christensen·Mar 13, 2002SaveLearn