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Condensed Matter papers — page 67

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Electron spin relaxation by nuclei in semiconductor quantum dots
We have studied theoretically the electron spin relaxation in semiconductor quantum dots via interaction with nuclear spins. The relaxation is shown to be determined by three processes: (i) -- the…
I. A. Merkulov, Al. L. Efros, M. RosenFeb 15, 2002
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Simple Simulational Model for Stocks Markets
A new model for stocks markets using integer values for each stock price is presented. In contrast with previously reported models, the variables used in the model are not of binary type, but of more…
Juan R. SanchezFeb 15, 2002
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Resistance and Resistance Fluctuations in Random Resistor Networks Under Biased Percolation
We consider a two-dimensional random resistor network (RRN) in the presence of two competing biased percolations consisting of the breaking and recovering of elementary resistors. These two processes…
C. Pennetta, L. Reggiani, Gy. Trefán et al.Feb 15, 2002
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Complex Diffusion Monte-Carlo method: tests by the simulations of 2D electron in magnetic field and 2D fermions-anyons in parabolic well
We propose a new Complex Diffusion Monte Carlo (CDMC) method for the simulation of quantum systems with complex wave function. In CDMC the modulus and phase of wave function are simulated both in…
B. Abdullaev, M. Musakhanov, A. NakamuraFeb 15, 2002
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Bistability and macroscopic quantum coherence in a BEC of 7Li
We consider a Bose-Einstein condensate (BEC) of 7Li in a situation where the density undergoes a symmetry breaking in real space. This occurs for a suitable number of condensed atoms in a double…
A. Montina, F. T. ArecchiFeb 14, 2002
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Rising Level of Public Exposure to Mobile Phones: Accumulation through Additivity and Reflectivity
A dramatic development occurring in our daily life is the increasing use of mobile equipment including mobile phones and wireless access to the Internet. They enable us to access several types of…
Tsuyoshi HondouFeb 14, 2002
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Viscous fingering and a shape of an electronic droplet in the Quantum Hall regime
We show that the semiclassical dynamics of an electronic droplet confined in the plane in a quantizing inhomogeneous magnetic field in the regime when the electrostatic interaction is negligible is…
Oded Agam, Eldad Bettelheim, P. Wiegmann et al.Feb 14, 2002
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Lower energy bounds for quantum lattice Hamiltonians
We derive general lower energy bounds for the ground state energy of any translationally invariant quantum lattice Hamiltonian. The bounds are given by the ground state energy of renormalized…
Dean Lee, Nathan SalwenFeb 13, 2002
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Magnetic order in the Shastry-Sutherland model
The ground state properties of the Shastry-Sutherland model in the presence of an external field are investigated by means of variational states built up from unpaired spins (monomers) and singlet…
A. Fledderjohann, K. -H. MuetterFeb 12, 2002
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Biological Networks
In this review, we give an introduction to the structural and functional properties of the biological networks. We focus on three major themes: topology of complex biological networks like the…
Indrani BoseFeb 12, 2002
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Lieb Mode in a Quasi One-Dimensional Bose-Einstein Condensate of Atoms
We calculate the dispersion relation associated with a solitary wave in a quasi-one-dimensional Bose-Einstein condensate of atoms confined in a harmonic, cylindrical trap in the limit of weak and…
A. D. Jackson, G. M. KavoulakisFeb 11, 2002
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Planar Dirac fermions in long-range-correlated random vector potential
We study the behavior of two-dimensional Dirac fermions in the presence of a static long-range-correlated random vector potential. By applying an exact path integral representation for the propagator…
D. V. Khveshchenko, A. G. YashenkinFeb 11, 2002
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Vortex Rings and Lieb Modes in a Cylindrical Bose-Einstein Condensate
We present a calculation of a solitary wave propagating along a cylindrical Bose-Einstein trap, which is found to be a hybrid of a one-dimensional (1D) soliton and a three-dimensional (3D) vortex…
S. Komineas, N. PapanicolaouFeb 11, 2002
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Stable Magnetostatic Solitons in Yttrium Iron Garnet Film Waveguides for Tilted in-Plane Magnetic Fields
The possibility of nonlinear pulses generation in Yttrium Iron Garnet thin films for arbitrary direction between waveguide and applied static in-plane magnetic field is considered. Up to now only the…
R. Khomeriki, L. TkeshelashviliFeb 10, 2002
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Ferromagnets and antiferromagnets in the effective Lagrangian perspective
Nonrelativistic systems exhibiting collective magnetic behavior are analyzed within the framework of effective Lagrangians. The method, which formulates the dynamics of the system in terms of…
Christoph P. HofmannFeb 9, 2002
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Greying of the Dark Soliton: Depletion in the Anomalous Mode of the Bogoliubov Theory
Quantum depletion from an atomic quasi one dimensional Bose-Einstein condensate with a dark soliton is studied in a framework of the Bogoliubov theory. Depletion is dominated by an anomalous mode…
Jacek Dziarmaga, Krzysztof SachaFeb 8, 2002
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Electron Spin Injection at a Schottky Contact
We investigate theoretically electrical spin injection at a Schottky contact between a spin-polarized electrode and a non-magnetic semiconductor. Current and electron density spin-polarizations are…
J. D. Albrecht, D. L. SmithFeb 7, 2002
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Compression and diffusion: a joint approach to detect complexity
The adoption of the Kolmogorov-Sinai (KS) entropy is becoming a popular research tool among physicists, especially when applied to a dynamical system fitting the conditions of validity of the Pesin…
P. Allegrini, V. Benci, P. Grigolini et al.Feb 7, 2002
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Competition Among Companies: Coexistence and Extinction
We study a spatially homogeneous model of a market where several agents or companies compete for a wealth resource. In analogy with ecological systems the simplest case of such models shows a kind of…
Marcelo Kuperman And Horacio WioFeb 6, 2002
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Equilibrium and stability properties of a coupled two-component Bose-Einstein condensate
The equilibrium and stability properties of a coupled two-component BEC is studied using a variational method and the one-dimensional model of Williams and collaborators. The variational parameters…
Chi-Yong Lin, E. J. V. de Passos, M. S. Hussein et al.Feb 6, 2002
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Low-dimensional Bose gases
We present an improved many-body T-matrix theory for partially Bose-Einstein condensed atomic gases by treating the phase fluctuations exactly. The resulting mean-field theory is valid in arbitrary…
U. Al Khawaja, J. O. Andersen, N. P. Proukakis et al.Feb 6, 2002
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New physical principles of contact thermoelectric cooling
We suggest a new approach to the theory of the contact thermoelectric cooling (Peltier effect). The metal-metal, metal-n-type semiconductor, metal-p-type semiconductor, p-n junction contacts are…
Yu. G. Gurevich, G. N. Logvinov, O. Yu. Titov et al.Feb 6, 2002
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X-ray fluorescence holography: going beyond the diffraction limit
X-ray fluorescence holography (XFH) is a method for obtaining diffraction-limited images of the local atomic structure around a given type of emitter. The reconstructed wave-field represents a…
S. Marchesini, C. S. Fadley, F. J. Garcia de AbajoFeb 5, 2002
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Yet another hysteresis model
A hysteresis model based on the assumption of fixed order magnetization reversals is proposed. The model uses one-dimensional diagram for representing states of a system despite of two-dimensional…
Sergey LangvagenFeb 5, 2002
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Occam factors and model-independent Bayesian learning of continuous distributions
Learning of a smooth but nonparametric probability density can be regularized using methods of Quantum Field Theory. We implement a field theoretic prior numerically, test its efficacy, and show that…
Ilya Nemenman, William BialekFeb 5, 2002
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