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Condensed Matter papers — page 119

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On the criterion for Bose-Einstein condensation for particles in traps
We consider the criterion for Bose condensation for particles in a harmonic trap. For a fixed angular momentum, the lowest energy state for a cloud of bosons with attractive interactions is the…
C. J. Pethick, L. P. PitaevskiiApr 12, 2000
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Multifractality in Time Series
We apply the concepts of multifractal physics to financial time series in order to characterize the onset of crash for the Standard & Poor's 500 stock index x(t). It is found that within the…
Enrique CanessaApr 11, 2000
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Generalized Entropy Composition with Different q Indices: A Trial
We analyze systematically composable composite entropy of two Tsallis subsystems with different q indices. H-theorem and thermal balance relation are commented.
K. Sasaki, M. HottaApr 11, 2000
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Systems with superabsorbing states
We report on some extensive analysis of a recently proposed model [A. Lipowski Phys. Rev. E 60, 6255 (1999)] with infinitely many absorbing states. By performing extensive Monte Carlo…
Pablo I. Hurtado, Miguel A. MunozApr 10, 2000
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Comment on "The Transition Temperature of the Dilute Interacting Bose Gas" and on "Transition Temperature of a Uniform Bose Gas"
It is pointed out that first, contrary to the claim by Baym et al.[Phys. Rev. Lett 83, 1703 (1999)], the shift in the transition temperature of a weakly interacting Bose gas can be calculated…
Adriaan M. J. SchakelApr 10, 2000
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A model of a pumped continuous atom laser
We present a model of a cw atom laser based on a system of coupled GP equations. The model incorporates continuous Raman outcoupling, pumping and three-body recombination. The outcoupled field has…
N. Robins, C. Savage, E. OstrovskayaApr 9, 2000
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Simple description of metastable phase decay on wide spectrum of activities
A new simple method for description of the nucleation process on the wide class of heterogeneous centers is given. The nucleation occurs on the heterogeneous centers with different heights of…
V. KurasovApr 9, 2000
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Magnetic Excitations in the Spin Gap System TlCuCl3
Single-crystal neutron inelastic scattering was performed in order to investigate the magnetic excitations in the spin gap system TlCuCl3. The constant- Q energy scan profiles were…
A. Oosawa, T. Kato, H. Tanaka et al.Apr 7, 2000
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Subdiffusive fluctuations of "pulled" fronts with multiplicative noise
We study the propagation of a ``pulled'' front with multiplicative noise that is created by a local perturbation of an unstable state. Unlike a front propagating into a metastable state,…
Andrea Rocco, Ute Ebert, Wim van SaarloosApr 6, 2000
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Bose-Einstein condensation in inhomogeneous Josephson arrays
We show that spatial Bose-Einstein condensation of non-interacting bosons occurs in dimension d < 2 over discrete structures with inhomogeneous topology and with no need of external confining…
R. Burioni, D. Cassi, I. Meccoli et al.Apr 6, 2000
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Periodic Ground States in the Neutral Falicov-Kimball Model in Two Dimensions
We consider the Falicov-Kimball model in two dimensions in the neutral case, i.e, the number of mobile electrons is equal to the number of ions. For rational densities between 1/3 and 2/5 we prove…
Karl Haller, Tom KennedyApr 6, 2000
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Magneto-optical control of bright atomic solitons
In previous work we showed that bright atomic solitons can arise in spinor Bose-Einstein condensates in the form of gap solitons even for repulsive many-body interactions. Here we further explore the…
S. Potting, O. Zobay, P. Meystre et al.Apr 6, 2000
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Generalized strategies in the Minority Game
We show analytically how the fluctuations (i.e. standard deviation) in the Minority Game (MG) can be made to decrease below the random coin-toss limit if the agents use more general behavioral…
M. Hart, P. Jefferies, N. F. Johnson et al.Apr 5, 2000
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Ratchet effect in dc SQUIDs
We analyzed voltage rectification for dc SQUIDs biased with ac current with zero mean value. We demonstrate that the reflection symmetry in the 2-dimensional SQUID potential is broken by an applied…
S. Weiss, D. Koelle, J. Mueller et al.Apr 5, 2000
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Applicability of Fermi golden rule and possibility of low-field runaway transport in nitrides
In order to justify applicability of the standard approach of perturbation theory for the description of transport phenomena in wide-band polar semiconductors with strong electron-phonon…
S. M. Komirenko, K. W. Kim, M. A. Stroscio et al.Apr 5, 2000
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Observation of Nanometer-Scale Rolling Motion Mediated by Commensurate Contact
We report, through experimental observations and computer simulations, that atomic lattice interlocking can determine whether an object rolls or slides on a surface. We have quantitatively…
M. R. Falvo, J. Steele, A. Buldum et al.Apr 5, 2000
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Novel type of orbital ordering: complex orbitals in doped Mott insulators
An orbital ordering, often observed in Mott insulators with orbital degeneracy, is usually supposed to disappear with doping, e.g. in the ferromagnetic metallic phase of manganites. We propose that…
Daniel KhomskiiApr 4, 2000
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On the Bragg, Leibfried, and Modified Leibfried Numbers
The Bragg, Leibfried, and modified Leibfried numbers are defined in the context of a theory of dislocation-mediated melting, and their values are determined from the properties of the dislocation…
Leonid Burakovsky, Dean L. Preston, Richard R. SilbarApr 4, 2000
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Quantum-Mechanical Non-Perturbative Response of Driven Chaotic Mesoscopic Systems
Consider a time-dependent Hamiltonian H(Q,P;x(t)) with periodic driving x(t)=A(Ωt). It is assumed that the classical dynamics is chaotic, and that its power-spectrum extends over some…
Doron Cohen, Tsampikos KottosApr 3, 2000
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Effective Charge and Spin Hamiltonian for the Quarter-Filled Ladder Compound α'-NaV2O5
An effective intra- and inter-ladder charge-spin hamiltonian for the quarter-filled ladder compound α'-NaV2O5 has been derived by using the standard canonical transformation method. In…
Debanand Sa, C. GrosApr 3, 2000
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Bloch electron in a magnetic field and the Ising model
The spectral determinant det(H-εI) of the Azbel-Hofstadter Hamiltonian H is related to Onsager's partition function of the 2D Ising model for any value of magnetic flux Φ=2πP/Q through an…
I. V. KrasovskyApr 3, 2000
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A class of N-body problems with nearest- and next-to-nearest neighbour interactions
We obtain the exact ground state and a part of the excitation spectrum in one dimension on a line and the exact ground state on a circle in a case where N particles are interacting via nearest- and…
Guy Auberson, Sudhir R. Jain, Avinash KhareApr 3, 2000
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Melting as a String-Mediated Phase Transition
We present a theory of the melting of elemental solids as a dislocation-mediated phase transition. We model dislocations near melt as non-interacting closed strings on a lattice. In this framework we…
Leonid Burakovsky, Dean L. Preston, Richard R. SilbarApr 3, 2000
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Absorption in periodic layered structures
Photonic band structure of metal-dielectric and semiconductor-dielectric layered structures are studied in the presence of a strong absorption. It is shown that absorption can enlarge some gaps by as…
Alexander Moroz, Adriaan Tip, Jean-Michel CombesApr 1, 2000
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Bose-Einstein condensation with magnetic dipole-dipole forces
Ground-state solutions in a dilute gas interacting via contact and magnetic dipole-dipole forces are investigated. To the best of our knowledge, it is the first example of studies of the…
K. Goral, K. Rzazewski, T. PfauMar 31, 2000
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