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Condensed Matter papers — page 90

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Enhancement of Nuclear Spin Superradiance by Electron Resonator
Superradiance of nuclear spins is considered, when the nuclei interact via hyperfine forces with electrons of a ferromagnet. The consideration is based on a microscopic model. If the sample, coupled…
V. I. Yukalov, E. P. YukalovaApr 16, 2001
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Dipolar induced anisotropy in the random-field Ising model
The crystalline ferromagnet with dipole-dipole interactions is studied within the framework of the three-dimensional random-field Ising model. The field distribution function and the analytic…
L. L. Afremov, A. V. PanovApr 13, 2001
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Enhancement of Rabi Splitting in a Microcavity with an Embedded Superlattice
We have observed a large coupling between the excitonic and photonic modes of an AlAs/AlGaAs microcavity filled with an 84-( Å)/20( Å) GaAs/AlGaAs superlattice. Reflectivity measurements on…
J. H. Dickerson, E. E. Mendez, A. A. Allerman et al.Apr 12, 2001
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Kane Oscillator
The energy spectrum and wave functions for Kane oscillator describing the spectra of electrons, light hole and spin-orbit-splitting bands in a quantum dots with harmonic lateral confinement is found.
F. M. Gashimzade, A. M. BabevApr 12, 2001
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Phase of bi-particle localized states for the Cooper problem in two-dimensional disordered systems
The Cooper problem is studied numerically for the Anderson model with disorder in two-dimensions. It is shown that the attractive Hubbard interaction creates a phase of bi-particle localized states…
J. Lages, D. L. ShepelyanskyApr 11, 2001
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Fermi Surface Measurements on the Low Carrier Density Ferromagnet Ca1-xLaxB6 and SrB6
Recently it has been discovered that weak ferromagnetism of a dilute 3D electron gas develops on the energy scale of the Fermi temperature in some of the hexaborides; that is, the Curie temperature…
Donavan Hall, D. P. Young, Z. Fisk et al.Apr 10, 2001
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The simulation of the spin ground states of the coulomb clusters in a broad 2D parabolic well
By variational Monte-Carlo method developed Ceperley et al. for the simulation of fermi systems in macroscopic confining potential well we simulate various spin ground states of the coulomb clusters…
B. Abdullaev, A. D. Kidisyuk, M. M. MusakhanovApr 7, 2001
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Anomalous strength of membranes with elastic ridges
We report on a simulational study of the compression and buckling of elastic ridges formed by joining the boundary of a flat sheet to itself. Such ridges store energy anomalously: their resting…
B. A. DiDonna, T. A. WittenApr 6, 2001
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Temperature dependence of current self-oscillations and electric field domains in sequential tunneling doped superlattices
We examine how the current--voltage characteristics of a doped weakly coupled superlattice depends on temperature. The drift velocity of a discrete drift model of sequential tunneling in a doped…
David Sanchez, L. L. Bonilla, G. PlateroApr 6, 2001
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Polynomial Observables in the Graph Partitioning Problem
Although NP-Complete problems are the most difficult decisional problems, it is possible to discover in them polynomial (or easy) observables. We study the Graph Partitioning Problem showing that it…
M. A. MarchisioApr 6, 2001
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Two-Loop Effective Potential of O(N)-Symmetric Scalar QED in 4-epsilon Dimensions
The effective potential of scalar QED is computed analytically up to two loops in the Landau gauge. The result is given in 4-epsilon dimensions using minimal subtraction and epsilon-expansions. In…
H. Kleinert, B. Van den BosscheApr 6, 2001
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Nonlinear dynamics of the classical isotropic Heisenberg antiferromagnetic chain: the sigma model sector and the kink sector
We identify two distinct low-energy sectors in the classical isotropic antiferromagnetic Heisenberg spin-S chain. In the continuum limit, we show that two types of rotation generators arise for the…
Radha Balakrishnan, Rossen DandoloffApr 5, 2001
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Steady state quantum mechanics of thermally relaxing systems
A theoretical description of quantum mechanical steady states is developed. Applications for simple quantum mechanical systems described in terms of coupled level structures yield a formulation…
D. Segal, A. NitzanApr 3, 2001
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Software Corrections of Vocal Disorders
We discuss how vocal disorders can be post-corrected via a simple nonlinear noise reduction scheme. This work is motivated by the need of a better understanding of voice dysfunctions. This would…
Lorenzo Matassini, Claudia ManfrediApr 3, 2001
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Momentum transferred to a trapped Bose-Einstein condensate by stimulated light scattering
The response of a trapped Bose-Einstein condensed gas to a density perturbation generated by a two-photon Bragg pulse is investigated by solving the time-dependent Gross-Pitaevskii equation. We…
A. Brunello, F. Dalfovo, L. Pitaevskii et al.Apr 3, 2001
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Probabilistic Approach to Pattern Selection
The problem of pattern selection arises when the evolution equations have many solutions, whereas observed patterns constitute a much more restricted set. An approach is advanced for treating the…
V. I. YukalovApr 2, 2001
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Decoherence and dephasing in coupled Josephson-junction qubits
We investigate the decoherence and dephasing of two coupled Josephson qubits. With the interaction between the qubits being generated by current-current correlations, two different situations in…
Michele Governale, Milena grifoni, Gerd SchoenApr 2, 2001
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Twin model for orthorhombic perovskites
We present a detailed single crystal x-ray diffraction study of twinned orthorhombic perovskites. The diffraction pattern can be indexed on a 2apx2apx2ap lattice, but does not obey cubic…
Bas B. Van Aken, Auke Meetsma, Thomas T. M. PalstraMar 30, 2001
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Atom laser dynamics
An ideal atom laser would produce an atomic beam with highly stable flux and energy. In practice the stability is likely to be limited by technical noise and nonlinear dynamical effects. We…
Nicholas Robins, Craig Savage, Elena A. OstrovskayaMar 29, 2001
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Firm Diversification and the Law of Proportionate Effect
The paper presents an analysis performed over the worldwide top 150 firms in the pharmaceutical industry. It begins with a test of the Gibrat's Law of Proportionate Effect finding, in line with…
Giulio BottazziMar 28, 2001
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Solitons and vortices in ultracold fermionic gases
We investigate the possibilities of generation of solitons and vortices in a degenerate gas of neutral fermionic atoms. In analogy with, already experimentally demonstrated, technique applied to…
T. Karpiuk, M. Brewczyk, K. RzazewskiMar 27, 2001
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New superconducting states in the Hubbard model
By acting on the excited states at half-filling in the positive-U Hubbard model with the η-pairing operators, we found some new superconducting states in the Hubbard model away from half-filling.…
Sze-Shiang Feng, Bin Wang, Elcio AbdallaMar 27, 2001
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Coherent Effects under Suppressed Spontaneous Emission
An ensemble of resonance atoms is considered, which are doped into a medium with well developed polariton effect, when in the spectrum of polariton states there is a band gap. If an atom with a…
V. I. YukalovMar 27, 2001
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Non-Gaussian equilibrium in a long-range Hamiltonian system
We study the dynamics of a system of N classical spins with infinite-range interaction. We show that, when the thermodynamic limit is taken before the infinite-time limit, the system does not relax…
V. Latora, A. Rapisarda, C. TsallisMar 26, 2001
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Shot noise in coupled dots and the "fractional charges"
We consider the problem of shot noise in resonant tunneling through double quantum dots in the case of interacting particles. Using a many-body quantum mechanical description we evaluate the energy…
Brahim Elattari, S. A. GurvitzMar 26, 2001
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