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Condensed Matter papers — page 262

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Ab Initio Calculation of Crystalline Electric Fields and Kondo Temperatures in Ce-Compounds
We have calculated the band-f hybridizations for CexLa1-xM3 compounds (x=1 and x→ 0; M=Pb, In, Sn, Pd) within the local density approximation and fed this into a…
J. E. Han, M. Alouani, D. L. CoxMay 20, 1996
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Finite Size Scaling Analysis of Biased Diffusion on Fractals
Diffusion on a T fractal lattice under the influence of topological biasing fields is studied by finite size scaling methods. This allows to avoid proliferation and singularities which would arise in…
G. Sartoni, A. L. StellaMay 20, 1996
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Umklapp Processes for Electrons and Their Renormalisation Group Flow
We study Umklapp couplings and their renormalisation group flow for electrons in a two dimensional lattice. It is shown that the effective low energy Hamiltonian involves not only forward scattering,…
Deepak Kumar, R. RajaramanMay 20, 1996
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Symmetries of an Extended Hubbard Model
An extended Hubbard model with phonons is considered on a D-dimensional lattice. The symmetries of the model are studied in various cases. It is shown that for a certain choice of the parameters a…
Bianca L. Cerchiai, Peter SchuppMay 20, 1996
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Effect of Interactions on the Critical Temperature of a Dilute Bose gas
Due to the observation of Bose-Einstein condensation in dilute atomic 87Rb and 23Na vapors last year, there is currently a great interest in the properties of a degenerate Bose gas. One…
M. Bijlsma, H. T. C. StoofMay 20, 1996
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Dynamics of Collapse of a Confined Bose Gas
Rigorous results on the nonlinear dynamics of a dilute Bose gas with a negative scattering length in an harmonic magnetic trap are presented and sufficient conditions for the collapse of the system…
L. P. PitaevskiiMay 20, 1996
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Excitation of Small Quantum Systems by High-Frequency Fields
The excitation by a high frequency field of multi--level quantum systems with a slowly varying density of states is investigated. A general approach to study such systems is presented. The Floquet…
Naama Brenner, Shmuel FishmanMay 20, 1996
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Composite fermions as solitons in the half-filled Landau level
Hold temporarily. Revised version in progress
Yong Baek KimMay 19, 1996
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Specific heat of high temperature superconductors: Role of ψ4 term in Ginzburg--Landau free energy
We have derived the expression for the specific heat by using Ginzburg-Landau (GL) theory by taking ψ4 into account in the Hartree approximation. Without this term, the specific heat…
Bikash. Ch. Gupta, K. K. NandaMay 19, 1996
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Inter-site Coulomb interaction and Heisenberg exchange
Based on exact diagonalization results for small clusters we discuss the effect of inter-site Coulomb repulsion in Mott-Hubbard or charge transfer insulators. Whereas the exchange constant J for…
R. Eder, J. van den Brink, G. A. SawatzkyMay 19, 1996
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Statistics of holons and spinons in the t-J model
We study the statistics of holons and spinons in the framework of the gauge theory. We start with the t-J model in the slave-boson formalism and use Chern-Simons gauge theory to study the statistics…
I. Ichinose, T. Matsui, K. SakakibaraMay 19, 1996
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Coherent Charge Transport in Metallic Proximity Structures
We develop a detailed microscopic analysis of electron transport in normal diffusive conductors in the presence of proximity induced superconducting correlation. We calculated the linear conductance…
A. A. Golubov, F. K. Wilhelm, A. D. ZaikinMay 18, 1996
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Integration Approach to Ising Models
An integral representation of the partition function for general n-dimensional Ising models with nearest or non-nearest neighbours interactions is given. The representation is used to derive some…
Sergio Albeverio, Shao-Ming FeiMay 18, 1996
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Quantum Griffiths Singularities in the Transverse-Field Ising Spin Glass
We report a Monte Carlo study of the effects of fluctuations in the bond distribution of Ising spin glasses in a transverse magnetic field, in the paramagnetic phase in the T 0…
Muyu Guo, R. N. Bhatt, David A. HuseMay 17, 1996
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Monte Carlo Simulations of Sexual Reproduction
Modifying the Redfield model of sexual reproduction and the Penna model of biological aging, we compare reproduction with and without recombination in age-structured populations. In contrast to…
D. Stauffer, P. M. C. de Oliveira, S. M. Moss de Oliveira et al.May 17, 1996
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The anharmonic electron-phonon problem
The anharmonic electron-phonon problem is solved in the infinite-dimensional limit using quantum Monte Carlo simulation. Charge-density-wave order is seen to remain at half filling even though the…
J. K. Freericks, Mark Jarrell, G. D. MahanMay 17, 1996
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Multigrid Method versus Staging Algorithm for PIMC Simulations
We present a comparison of the performance of two non-local update algorithms for path integral Monte Carlo (PIMC) simulations, the multigrid Monte Carlo method and the staging algorithm. Looking at…
Wolfhard Janke, Tilman SauerMay 17, 1996
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Anomalous density of states of a Luttinger liquid in contact with a superconductor
We study the frequency and space dependence of the local tunneling density of states of a Luttinger liquid (LL) which is connected to a superconductor. This coupling strongly modifies the…
C. Winkelholz, Rosario Fazio, F. W. J. Hekking et al.May 17, 1996
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One particle interchain hopping in coupled Hubbard chains
Interchain hopping in systems of coupled chains of correlated electrons is investigated by exact diagonalizations and Quantum-Monte-Carlo methods. For two weakly coupled Hubbard chains at…
D. Poilblanc, H. Endres, F. Mila et al.May 17, 1996
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Drude weight and total optical weight in a t-t'-J model
We study the Drude weight D and the total optical weight K for a t-t'-J model on a square lattice that exhibits a metallic phase-modulated antiferromagnetic ground state close to half-filling.…
Gregory C. PsaltakisMay 16, 1996
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Majority Rule at Low Temperatures on the Square and Triangular Lattices
We consider the majority rule renormalization group transformation applied to nearest neighbor Ising models. For the square lattice with 2 by 2 blocks we prove that if the temperature is sufficiently…
Tom KennedyMay 16, 1996
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Invaded cluster algorithm for Potts models
The invaded cluster algorithm, a new method for simulating phase transitions, is described in detail. Theoretical, albeit nonrigorous, justification of the method is presented and the algorithm is…
J. Machta, Y. S. Choi, A. Lucke et al.May 16, 1996
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A Phase-Field Model of Spiral Dendritic Growth
Domains of condensed-phase monolayers of chiral molecules exhibit a variety of interesting nonequilibrium structures when formed via pressurization. To model these domain patterns, we add a complex…
Royce Kam, Herbert LevineMay 16, 1996
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Anharmonic Decay of Vibrational States in Amorphous Silicon
Anharmonic decay rates are calculated for a realistic atomic model of amorphous silicon. The results show that the vibrational states decay on picosecond timescales and follow the two-mode density of…
Jaroslav Fabian, Philip B. AllenMay 16, 1996
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A more accurate analysis of Bose-Einstein condensation in harmonic traps
Using the Euler-Maclaurin summation we calculate analytically the internal energy for non-interacting bosons confined within a harmonic oscillator potential. The specific heat shows a sharp λ-like…
H. Haugerud, T. Haugset, F. RavndalMay 16, 1996
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