Intersubband absorption linewidth in GaAs quantum wells due to scattering by interface roughness, phonons, alloy disorder, and impuritiesWe calculate the intersubband absorption linewidth in quantum wells (QWs) due to scattering by interface roughness, LO phonons, LA phonons, alloy disorder, and ionized impurities, and compare it with…Takeya Unuma, Masahiro Yoshita, Takeshi Noda et al.·Aug 9, 2002SaveLearn
On the nature of ferromagnetism in diluted magnetic semiconductors: GaAs:Mn, GaP:MnA microscopic Hamiltonian for interacting manganese impurities in diluted magnetic semiconductors (DMS) is derived. It is shown that in p -type III-V DMS the indirect exchange between Mn impurities…V. A. Ivanov, P. M. Krstajic, F. M. Peeters et al.·Aug 9, 2002SaveLearn
Atomic Scale Fractal Dimensionality in ProteinsThe soft condensed matter of biological organisms exhibits atomic motions whose properties depend strongly on temperature and hydration conditions. Due to the superposition of rapidly fluctuating…Duccio Medini, A. Widom·Aug 8, 2002SaveLearn
Relativistic treatment of harmonics from impurity systems in quantum wiresWithin a one particle approximation of the Dirac equation we investigate a defect system in a quantum wire. We demonstrate that by minimally coupling a laser field of frequency omega to such an…O. A. Castro-Alvaredo, A. Fring, C. Figueira de Morisson Faria·Aug 7, 2002SaveLearn
Polarization of superfluid turbulenceWe show that normal fluid eddies in turbulent helium II polarize the tangle of quantized vortex lines present in the flow, thus inducing superfluid vorticity patterns similar to the driving normal…Carlo F. Barenghi, Sarah Hulton, David C. Samuels·Aug 7, 2002SaveLearn
Investigation of the structure of beta-TantalumThe local structure of beta-tantalum was investigated by comparing experimental extended x-ray absorption fine structure (EXAFS) measurements with calculated spectra of proposed models. Four possible…Aiqin Jiang, Anto Yohannan, Neme O. Nnolim et al.·Aug 6, 2002SaveLearn
Low-temperature spin relaxation in n-type GaAsLow-temperature electron spin relaxation is studied by the optical orientation method in bulk n-GaAs with donor concentrations from 1014 cm-3 to 5x1017 cm-3. A peculiarity related to the…R. I. Dzhioev, K. V. Kavokin, V. L. Korenev et al.·Aug 5, 2002SaveLearn
Superfluidity in a Doped Helium DropletPath Integral Monte Carlo calculations of the superfluid density throughout 4He droplets doped with linear impurities (HCN)n are presented. After deriving a local estimator for the superfluid…E. W. Draeger, D. M. Ceperley·Aug 5, 2002SaveLearn
Entangled Vortices: Onsager's geometrical picture of superfluid phase transitionsSuperfluid phase transitions are discussed from a geometrical perspective as envisaged by Onsager. The approach focuses on vortex loops which close to the critical temperature form a fluctuating…Adriaan M. J. Schakel·Aug 4, 2002SaveLearn
Jahn-Teller instability in C6H6+ and C6H6- revisitedThe benzene cation (C6H6+) has a doublet (e1g) ground state in hexagonal ring (D6h) geometry. Therefore a Jahn-Teller (JT) distortion will lower the energy. The present theoretical study yields…Vasili Perebeinos, Philip B. Allen, Mark Pederson·Aug 2, 2002SaveLearn
Landau damping of transverse quadrupole oscillations of an elongated Bose-Einstein condensateWe study the interaction between low-lying transverse collective oscillations and thermal excitations of an elongated Bose-Einstein condensate by means of perturbation theory. We consider a…M. Guilleumas, L. P. Pitaevskii·Aug 2, 2002SaveLearn
The Physical Basis of Integrable Spin ModelsIntegrable models are often constructed with real systems in mind. The exact solvability of the models leads to results which are unambiguous and provide the correct physical picture. In this review,…Indrani Bose·Aug 2, 2002SaveLearn
Macroscopic entanglement jumps in model spin systemsIn this paper, we consider some frustrated spin models for which the ground states are known exactly. The concurrence, a measure of the amount of entanglement can be calculated exactly for entangled…Indrani Bose, Emily Chattopadhyay·Aug 1, 2002SaveLearn
Credit Risk Contributions to Value-at-Risk and Expected ShortfallThis paper presents analytical solutions to the problem of how to calculate sensible VaR (Value-at-Risk) and ES (Expected Shortfall) contributions in the CreditRisk+ methodology. Via the ES…Alexandre Kurth, Dirk Tasche·Jul 31, 2002SaveLearn
Microwave saturation of the Rydberg states of electrons on heliumWe present measurements of the resonant microwave excitation of the Rydberg energy levels of surface state electrons on superfluid helium. The temperature dependent linewidth agrees well with…E. Collin, W. Bailey, P. Fozooni et al.·Jul 31, 2002SaveLearn
X-ray Absorption Near-Edge Structure calculations with pseudopotentials. Application to K-edge in diamond and alpha-quartzWe present a reciprocal-space pseudopotential scheme for calculating X-ray absorption near-edge structure (XANES) spectra. The scheme incorporates a recursive method to compute absorption cross…Mathieu Taillefumier, Delphine Cabaret, Anne-Marie Flank et al.·Jul 31, 2002SaveLearn
Density of states for the π-flux state with bipartite real random hopping only: A weak disorder approachGade [R. Gade, Nucl. Phys. B 398, 499 (1993)] has shown that the local density of states for a particle hopping on a two-dimensional bipartite lattice in the presence of weak disorder and in…C. Mudry, S. Ryu, A. Furusaki·Jul 30, 2002SaveLearn
To the problem of Poincare recurrences in generic Hamiltonian systemsWe discuss the problem of Poincare recurrences in area-preserving maps and the universality of their decay at long times. The work is related to to the results presented in Refs. [1,2].B. V. Chirikov, D. L. Shepelyansky·Jul 30, 2002SaveLearn
Analysis of the elasto-plastic response of a polygonal packingWe investigate the constitutive response of two-dimensional packed samples of polygons using molecular dynamics simulation. The incremental elasto-plastic response is examined in the pre-failure…F. Alonso-Marroquin, H. J. Herrmann, S. Luding·Jul 30, 2002SaveLearn
Superfluidity and Swallowtails; Hysteretic Behavior in Bose CondensatesWe present a theory of hysteretic phenomena in Bose gases, using superfluidity in one dimensional rings and in optical lattices as primary examples. Through this study we are able to give a physical…Erich J. Mueller·Jul 29, 2002SaveLearn
Comment on "Wave Refraction in Negative-Index Materials: Always Positive and Very Inhomogeneous"Wave refraction in negative-index media is always negative.W. T. Lu, J. B. Sokoloff, S. Sridhar·Jul 29, 2002SaveLearn
Review of the k-Body Embedded Ensembles of Gaussian Random MatricesThe embedded ensembles were introduced by Mon and French as physically more plausible stochastic models of many--body systems governed by one--and two--body interactions than provided by standard…L. Benet, H. A. Weidenmueller·Jul 26, 2002SaveLearn
Large amplitude behavior of the Grinfeld instability, Part I: High-order weakly nonlinear analysisAmplitude expansions are used to determine steady states of a semi-infinite solid subject to the Grinfeld instability in systems with a fixed (wave)length. We present two methods to obtain high-order…Peter Kohlert, Klaus Kassner, Chaouqi Misbah·Jul 26, 2002SaveLearn
Unconventional Metallic Magnetism in LaCrSb3Neutron-diffraction measurements in LaCrSb3 show a coexistence of ferromagnetic and antiferromagnetic sublattices below Tc=126 K, with ordered moments of 1.65(4) and 0.49(4) Bohr magnetons per…E. Granado, H. Martinho, M. S. Sercheli et al.·Jul 26, 2002SaveLearn
Spin Wave Response in the Dilute Quasi-one Dimensional Ising-like Antiferromagnet CsCo0.83Mg0.17Br3Inelastic neutron scattering profiles of spin waves in the dilute quasi-one-dimensional Ising-like antiferromagnet CsCo0.83Mg0.17Br3 have been investigated. Calculations of Sxx(Q,omega),…Y. S. Yang, F. Marsiglio, M. Madsen et al.·Jul 26, 2002SaveLearn