Quenched Spin Tunneling and Diabolical Points in Magnetic Molecules: II. Asymmetric ConfigurationsThe perfect quenching of spin tunneling first predicted for a model with biaxial symmetry, and recently observed in the magnetic molecule Fe8, is further studied using the discrete phase integral…Anupam Garg·Mar 9, 2000SaveLearn
Electronic structure of self-assembled quantum dots: comparison between density functional theory and diffusion quantum Monte CarloWe have calculated the exchange, correlation, and total electronic energy of a realistic InAs self-assembled quantum dot embedded in a GaAs matrix as a function of the number of electrons in the dot.…J. Shumway, L. R. C. Fonseca, J. P. Leburton et al.·Mar 9, 2000SaveLearn
Coulomb drag between one-dimensional conductorsWe have analyzed Coulomb drag between currents of interacting electrons in two parallel one-dimensional conductors of finite length L attached to external reservoirs. For strong coupling, the…Vadim Ponomarenko, Dmitri Averin·Mar 8, 2000SaveLearn
Synchronization in populations of globally coupled oscillators with inertial effectsA model for synchronization of globally coupled phase oscillators including ``inertial'' effects is analyzed. In such a model, both oscillator frequencies and phases evolve in time.…J. A. Acebron, L. L. Bonilla, R. Spigler·Mar 8, 2000SaveLearn
A critical review of techniques for Term Structure analysisFixed income markets share many features with the equity markets. However there are significant differences as well and many attempts have been done in the past to develop specific tools which…Livio Marangio, Alessandro Ramponi, Massimo Bernaschi·Mar 8, 2000SaveLearn
Tunnel splittings for one dimensional potential wells revisitedThe WKB and instanton answers for the tunnel splitting of the ground state in a symmetric double well potential are both reduced to an expression involving only the functionals of the potential,…Anupam Garg·Mar 8, 2000SaveLearn
Quenched Spin Tunneling and Diabolical Points in Magnetic Molecules: I. Symmetric ConfigurationsThe perfect quenching of spin tunneling that has previously been discussed in terms of interfering instantons, and has recently been observed in the magnetic molecule 8, is treated using a…Anupam Garg·Mar 8, 2000SaveLearn
Diabolical points in the magnetic spectrum of Fe8 moleculesThe magnetic molecule Fe8 has been predicted and observed to have a rich pattern of degeneracies in its spectrum as an external magnetic field is varied. These degeneracies have now been recognized…Anupam Garg·Mar 7, 2000SaveLearn
Diagonalization of a bosonic quadratic form using CCM: Application on a system with two interpenetrating square lattice antiferromagnetsWhile the diagonalization of a quadratic bosonic form can always be done using a Bogoliubov transformation, the practical implementation for systems with a large number of different bosons is a…Sven E. Krueger, Dirk Schmalfuss, Johannes Richter·Mar 7, 2000SaveLearn
Why does a protein fold?With the help of lattice Monte Carlo modelling of heteropolymers, we show that the necessary condition for a protein to fold on short call is to proceed through partially folded intermediates. These…R. A. Broglia, G. Tiana·Mar 7, 2000SaveLearn
Conductivity of composite systems: perturbation theory and multidimensional chessboardThe paper was withdrawn by the authorsI. M. Khalatnikov, A. Yu. Kamenshchik·Mar 7, 2000SaveLearn
Bose condensates at high angular momentaWe exploit the analogy with the Quantum Hall (QH) system to study weakly interacting bosons in a harmonic trap. For a δ-function interaction potential the ``yrast'' states with $L…S. Viefers, T. H. Hansson, S. M. Reimann·Mar 6, 2000SaveLearn
Three-dimensional vortex dynamics in Bose-Einstein condensatesWe simulate in the mean-field limit the effects of rotationally stirring a three-dimensional trapped Bose-Einstein condensate with a Gaussian laser beam. A single vortex cycling regime is found for a…B. M. Caradoc-Davies, R. J. Ballagh, P. B. Blakie·Mar 6, 2000SaveLearn
Bond-Ordering Model for the Glass TransitionWe consider the idea of bond ordering as a model for glass transition: a generic covalently bonded liquid may substantially reduce its energy through bond ordering, without undergoing significant…Saeid Davatolhagh, Bruce R. Patton·Mar 4, 2000SaveLearn
Mean parameter model for the Pekar-Fröhlich polaron in a multilayered heterostructureThe polaron energy and the effective mass are calculated for an electron confined in a finite quantum well constructed of GaAs/Alx Ga1-x As layers. To simplify the study we suggest a model in…M. A. Smondyrev, B. Gerlach, M. O. Dzero·Mar 1, 2000SaveLearn
Dependence of the physical properties of Nd0.5Ca0.5MnO3+δ on the oxydation state of MnWe present a comparative study of the magnetic, transport and structural properties of Nd0.5Ca0.5MnO3+δ [δ= 0.02(1) and 0.04(1)]. We have found significant differences between the low…Carlos Frontera, José Luis García-Muñoz, Anna Llobet et al.·Mar 1, 2000SaveLearn
Short, Medium and Long Range Spatial Correlations in Simple GlassesLocal stresses and pressures always exist in glasses. In this letter we consider their effects on the structure and structural correlations in simple glasses. We find that extreme values of local…Tamar Kustanovich, Zeev Olami·Mar 1, 2000SaveLearn
Reactive Hall responseThe zero temperature Hall constant RH, described by reactive (nondissipative) conductivities, is analyzed within linear response theory. It is found that in a certain limit, RH is directly related…X. Zotos, F. Naef, M. Long et al.·Feb 29, 2000SaveLearn
Long-range interaction and nonlinear localized modes in photonic crystal waveguidesWe develop the theory of nonlinear localised modes (intrinsic localised modes or discrete breathers) in two-dimensional (2D) photonic crystal waveguides. We consider different geometries of the…Serge F. Mingaleev, Yuri S. Kivshar, Rowland A. Sammut·Feb 29, 2000SaveLearn
Relationship between spiral and ferromagnetic states in the Hubbard model in the thermodynamic limitWe explore how the spiral spin(SP) state, a spin singlet known to accompany fully-polarized ferromagnetic (F) states in the Hubbard model, is related with the F state in the thermodynamic limit using…Ryotaro Arita, Hideo Aoki·Feb 29, 2000SaveLearn
Magnetic properties of the Hubbard model on three-dimensional lattices: fluctuation-exchange and two-particle self-consistent studiesThe relation between three-dimensional lattice structure and magnetism in correlated electron systems is explored for face centered cubic (FCC), body centered cubic (BCC), and simple cubic (SC)…Ryotaro Arita, Shigeki Onoda, Kazuhiko Kuroki et al.·Feb 29, 2000SaveLearn
d- and p-wave superconductivity mediated by spin fluctuations in two- and three-dimensional single-band repulsive Hubbard modelWe have systematically studied superconducting instabilities in the repulsive Hubbard model for d-wave and p-wave pairing in various 2D and 3D lattices. Using fluctuation exchange approximation, we…Ryotaro Arita, Kazuhiko Kuroki, Hideo Aoki·Feb 29, 2000SaveLearn
Response-theory for nonresonant hole burning: Stochastic dynamicsUsing non-linear response theory the time signals relevant for nonresonant spectral hole burning are calculated. The step-reponse function following the application of a high amplitude ac field…Gregor Diezemann·Feb 28, 2000SaveLearn
Nonlinear Effect of Transport Current on Response of Metals to Electromagnetic RadiationThe nonlinear interaction of DC current flowing in a thin metal film with an external low-frequency AC electromagnetic field is studied theoretically. The nonlinearity is related to the influence of…S. A. Derev'anko, G. B. Tkachev, V. A. Yampol'skii·Feb 28, 2000SaveLearn
Sonoluminescence as a Physical Vacuum ExcitationWe are discussing Schwinger'idea that physical mechanism of sonoluminescence is a physical vacuum excitation. This theory was based on the assumption that the sudden change of the rate of bubble…Yu. P. Stepanovsky, G. G. Sergeeva·Feb 28, 2000SaveLearn