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Condensed Matter papers — page 272

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van Hove Singularity effects in Strongly Correlated Fermions
We examine the effects of a van Hove singularity (vHs) in the density of states (DOS) of a two dimensional, t-t'-U Hubbard model within the local approximation. Within our approximation the…
Pinaki Majumdar, H. R. KrishnamurthyApr 10, 1996
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Fermions on half-quantum vortex
The spectrum of the fermion zero modes in the vicinity of the vortex with fractional winding number is discussed. This is inspired by the observation of the 1/2 vortex in high-temperature…
G. E. VolovikApr 9, 1996
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Electrodynamical Properties of High Tc Superconductors Studied with Polarized Angle Resolved Infrared Spectroscopy
Using infrared spectroscopy at grazing angle of incidence we study the electrodynamical properties of high temperature superconductors. We review some of our experiments where transverse polarized…
D. van der Marel, J. Schützmann, H. S. Somal et al.Apr 9, 1996
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Density Matrix Renormalization Group Applied to the Ground State of the XY-Spin-Peierls System
We use the density matrix renormalization group (DMRG) to map out the ground state of a XY-spin chain coupled to dispersionless phonons of frequency % ω. We confirm the existence of a critical…
L. G. Caron, S. MoukouriApr 9, 1996
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Correlation functions in the two-dimensional random-bond Ising model
We consider long strips of finite width L ≤ 13 sites of ferromagnetic Ising spins with random couplings distributed according to the binary distribution: $P(Jij)= 1 2 ( δ(Jij -J0)…
S. L. A. de Queiroz, R. B. StinchcombeApr 9, 1996
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Using network-flow techniques to solve an optimization problem from surface-physics
The solid-on-solid model provides a commonly used framework for the description of surfaces. In the last years it has been extended in order to investigate the effect of defects in the bulk on the…
U. Blasum, W. Hochstättler, C. Moll et al.Apr 9, 1996
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The One-Dimensional ANNNI model in a Transverse Field: Analytic and numerical study of Effective Hamiltonians
We consider a spin-12 chain with competing nearest and next-nearest neighbor interactions within a transverse magnetic field, which is known to be an equiavelent to the ANNNI model. When…
H. Rieger, G. UiminApr 9, 1996
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The critical exponents of the two-dimensional Ising spin glass revisited: Exact Ground State Calculations and Monte Carlo Simulations
The critical exponents for T0 of the two-dimensional Ising spin glass model with Gaussian couplings are determined with the help of exact ground states for system sizes up to L=50 and by a…
H. Rieger, L. Santen, U. Blasum et al.Apr 9, 1996
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Non-Fermi liquid theory of a compactified Anderson single-impurity model
We consider a version of the symmetric Anderson impurity model (compactified) which has a non-Fermi liquid weak coupling regime. We find that in the Majorana fermion representation, perturbation…
Guang-Ming Zhang, A. C. HewsonApr 9, 1996
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Fluid mixtures of parallel hard cubes
The direct correlation function of a fluid mixture of parallel hard cubes is obtained by using Rosenfeld's fundamental measure approximation. This approximation is thermodynamically consistent…
Jose A. CuestaApr 9, 1996
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Semiclassical and field theoretic studies of Heisenberg antiferromagnetic chains with frustration and dimerization
The Heisenberg antiferromagnetic spin chain with both dimerization and frustration is studied. The classical ground state has three phases (a Neel phase, a spiral phase and a colinear phase), around…
Sumathi Rao, Diptiman SenApr 9, 1996
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Time evolution of models described by one-dimensional discrete nonlinear Schrödinger equation
The dynamics of models described by a one-dimensional discrete nonlinear Schrödinger equation is studied. The nonlinearity in these models appears due to the coupling of the electronic motion to…
P. K. Datta, K. KunduApr 8, 1996
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On the flux phase conjecture at half-filling: an improved proof
We present a simplification of Lieb's proof of the flux phase conjecture for interacting fermion systems -- such as the Hubbard model --, at half filling on a general class of graphs. The main…
Nicolas Macris, Bruno NachtergaeleApr 8, 1996
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Spectral Properties of Statistical Mechanics Models
The full spectrum of transfer matrices of the general eight-vertex model on a square lattice is obtained by numerical diagonalization. The eigenvalue spacing distribution and the spectral rigidity…
Hendrik Meyer, Jean-Christian Anglès d'Auriac, Henrik BruusApr 8, 1996
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Bistability of persistent currents in mesoscopic rings
We study the persistent currents flowing in a mesoscopic ring threaded by a magnetic flux and connected to a stub of finite length. Multistability processes and Coulomb blockade are demonstrated to…
E. Anda, V. Ferrari, G. ChiappeApr 8, 1996
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Chiral sound waves from a gauge theory of 1D generalized statistics
A topological gauge field theory in one spatial dimension is studied, with the gauge fields as generators of two commuting U(1) Kauc-Moody algebras. Coupling of these gauge fields to nonrelativistic…
Silvio J. Benetton RabelloApr 6, 1996
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Josephson and Quasiparticle Tunneling between Anisotropically Paired Superconductors
Charge transport in tunnel junctions between singlet anisotropically paired superconductors is investigated theoretically making use of the Eilenberger equations for the quasiclassical Green…
Yury S. Barash, Anatoly A. SvidzinskyApr 5, 1996
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Magnetic Phase Diagram of Hubbard Model in Three Dimensions: the Second-Order Local Approximation
A local, second-order (truncated) approximation is applied to the Hubbard model in three dimensions. Lowering the temperature, at half-filling, the paramagnetic ground state becomes unstable towards…
A. N. Tahvildar-Zadeh, J. K. Freericks, M. JarrellApr 5, 1996
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Log-periodic corrections to scaling: exact results for aperiodic Ising quantum chains
Log-periodic amplitudes of the surface magnetization are calculated analytically for two Ising quantum chains with aperiodic modulations of the couplings. The oscillating behaviour is linked to the…
Dragi Karevski, Loic TurbanApr 5, 1996
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Phase transition of a Bose gas in a harmonic potential
We consider a dilute Bose gas confined by a harmonic potential. We define an appropriate thermodynamic limit and analyze the properties of the phases and phase transition in this limit. Critical…
Kedar Damle, T. Senthil, Satya N. Majumdar et al.Apr 5, 1996
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Theory of the optical conductivity of (TMTSF)2PF6 in the mid-infrared range
We propose an explanation of the mid-infrared peak observed in the optical conductivity of the Bechgaard salt (TMTSF)2PF6 in terms of electronic excitations. It is based on a numerical…
Julien Favand, Frédéric MilaApr 5, 1996
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Charge-density-waves and superconductivity as an alternative to phase separation in the infinite-U Hubbard-Holstein model
We investigate the density instabilities present in the infinite-U Hubbard-Holstein model both at zero and finite momenta as well as the occurrence of Cooper instabilities with a specific emphasis on…
F. Becca, M. Tarquini, M. Grilli et al.Apr 5, 1996
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The Kondo screening cloud: what can we learn from perturbation theory?
We analyse the role which the distance scale ξK = vF/TK plays in the single-impurity Kondo problem using renormalization group improved perturbation theory. We derive the scaling functions for…
Victor Barzykin, Ian AffleckApr 4, 1996
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Gauge invariant nonlinear electric transport in mesoscopic conductors
We use the scattering approach to investigate the nonlinear current-voltage characteristic of mesoscopic conductors. We discuss the leading nonlinearity by taking into account the self-consistent…
T. Christen, M. ButtikerApr 4, 1996
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Low-temperature conductance and DC current noise in a quantum wire with impurity
The nonlinear conductance for tunneling through an impurity in a Luttinger liquid and the nonequilibrium DC current noise are calculated exactly for low temperatures. We present a pedestrian pathway…
Ulrich WeissApr 4, 1996
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