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cond-mat/9405090
On the Non-invasive Measurement of the Intrinsic Quantum Hall Effect
With a model calculation, we demonstrate that a non-invasive measurement of intrinsic quantum Hall effect defined by the local chemical potential in a ballistic quantum wire can be achieved with the aid of a pair of voltage leads which are separated by potential barriers from the wire. B\"uttiker's formula is used to d...
1994-05-31
2009-10-22
[ "cond-mat" ]
D. P. Chu and P. N. Butcher
cond-mat/9405089
Simulation of forces on polymers due to slippage
We consider the force on the end of a polymer chain being pulled through a network at velocity $v$, using computer simulations. We develop algorithms for measuring the force on the end of the chain using lattice models of polymers. Our algorithm attaches a spring to the end being pulled and uses its average extension t...
1994-05-31
2009-10-22
[ "cond-mat" ]
J.M. Deutsch and Hyoungsoo Yoon
cond-mat/9405088
Depinning in a Random Medium
We develop a renormalized continuum field theory for a directed polymer interacting with a random medium and a single extended defect. The renormalization group is based on the operator algebra of the pinning potential; it has novel features due to the breakdown of hyperscaling in a random system. There is a second-ord...
1994-05-30
2009-10-22
[ "cond-mat" ]
H. Kinzelbach and M. Lassig
cond-mat/9405087
Raman Scattering Spectra of Elementary Electronic Excitations in Coupled Double-Quantum Well Structures
Using the time-dependent-local-density-approximation (TDLDA) within a self-consistent linear response theory, we calculate the elementary excitation energies and the associated inelastic light-scattering spectra of a strongly coupled two-component plasma in a double-quantum well system with electron occupation of symme...
1994-05-29
2009-10-22
[ "cond-mat" ]
P. I. Tamborenea and S. Das Sarma
cond-mat/9405084
Exactly solvable random matrix models with additional two-body interactions
It has been argued that despite remarkable success, existing random matrix theories are not adequate to describe disordered conductors in the metallic regime, due to the presence of certain two-body interactions in the effective Hamiltonian for the eigenvalues, in addition to the standard logarithmic interaction that a...
1994-05-27
2007-05-23
[ "cond-mat" ]
K.A.Muttalib
cond-mat/9405086
Localized electronic states and photoemission superconducting condensate in Bi$_{2}$Sr$_{2}$Ca$_{1}$Cu$_{2}$O$_{8+x}$
We present the first detailed angle-resolved photoemission evidence that there are two types of carriers that contribute to the photoemission superconducting condensate in $Bi_{2}Sr_{2}Ca_{1}Cu_{2}O_{8+x}$. Our data indicate that both itinerant and somewhat localized normal state carriers can contribute to the formatio...
1994-05-27
2009-10-22
[ "cond-mat" ]
Jian Ma, C.Quitmann, R.J.Kelley, G. Margaritondo, and M.Onellion (Dept of Phys. & Applied Superconductivity Center, UW-Madison, and EPFL, Lausanne, Switzerland.)
cond-mat/9405085
Thermodynamics and spin gap of the Heisenberg ladder calculated by the look-ahead Lanczos algorithm
We have developed an improved version of the quantum transfer matrix algorithm. The extreme eigenvalues and eigenvectors of the transfer matrix are calculated by the recently developed look-ahead Lanczos algorithm for non-Hermitian matrices with higher efficiency and accuracy than by the power method. We have applied t...
1994-05-27
2007-05-23
[ "cond-mat" ]
Matthias Troyer, Hirokazu Tsunetsugu and Diethelm Wuertz
cond-mat/9405083
Gauge-invariant response functions of fermions coupled to a gauge field
We study a model of fermions interacting with a gauge field and calculate gauge-invariant two-particle Green's functions or response functions. The leading singular contributions from the self-energy correction are found to be cancelled by those from the vertex correction for small $q$ and $\Omega$. As a result, the re...
1994-05-26
2009-10-22
[ "cond-mat" ]
Yong Baek Kim, Akira Furusaki, Xiao-Gang Wen, and Patrick A. Lee
cond-mat/9405075
Self Induced Quenched Disorder: A Model for the Glass Transition
We consider a simple spin system without disorder which exhibits a glassy regime. We show that this model can be well approximated by a system with quenched disorder which is studied with the standard methods developped in spin glasses. We propose that the glass transition is a point where quenched disorder is self ind...
1994-05-26
2009-10-22
[ "cond-mat" ]
J.P. Bouchaud and M. Mezard
cond-mat/9405079
Metastable Dynamics above the Glass Transition
The element of metastability is incorporated in the fluctuating nonlinear hydrodynamic description of the mode coupling theory (MCT) of the liquid-glass transition. This is achieved through the introduction of the defect density variable $n$ into the set of slow variables with the mass density $\rho$ and the momentum d...
1994-05-26
2009-10-22
[ "cond-mat" ]
Joonhyun Yeo and Gene F. Mazenko
cond-mat/9405074
Suppression of Persistent Currents in 1-D Disordered Rings by Coulomb Interaction
Effects of Coulomb interaction on persistent currents in disordered one-dimensional rings are numerically investigated. First of all effectiveness of the Hartree-Fock approximation is established on small systems. Then the calculations are done for systems with 40 electrons in 100 sites. It is found that the amplitude ...
1994-05-26
2009-10-22
[ "cond-mat" ]
H. Kato and D. Yoshioka
cond-mat/9405076
Electrons in a Strong Magnetic Field on a Disk
The problem of interacting electrons moving under the influence of a strong magnetic field in two dimensions on a finite disk is reconsidered. First, the results of exact diagonalizations for up to $N=9$ electrons for Coulomb as well as for a short--range interaction are used in the search for a peculiar ground state c...
1994-05-26
2009-10-22
[ "cond-mat" ]
M. Kasner and W. Apel
cond-mat/9405080
On the Inequivalence of Weak-Localization and Coherent Backscattering
We define a current-conserving approximation for the local conductivity tensor of a disordered system which includes the effects of weak localization. Using this approximation we show that the weak localization effect in conductance is not obtained simply from the diagram corresponding to the coherent back-scattering p...
1994-05-26
2009-10-22
[ "cond-mat" ]
Matthew B. Hastings, A. Douglas Stone, and Harold U. Baranger
cond-mat/9405078
Spin gap and superconductivity in the three-dimensional attractive Hubbard model
We study the phase diagram for the attractive ({\it i.e.,} negative-$U$) Hubbard model on a simple cubic lattice, through Monte Carlo simulations. We obtain the critical temperature, $T_c$, for superconductivity from a finite-size scaling analysis of the data for the pairing correlations. For fixed on-site attraction, ...
1994-05-26
2007-05-23
[ "cond-mat" ]
Raimundo R dos Santos
cond-mat/9405081
Quantum Field Theory Description of Tunneling in the Integer Quantum Hall Effect
We study the tunneling between two quantum Hall systems, along a quasi one-dimensional interface. A detailed analysis relates microscopic parameters, characterizing the potential barrier, with the effective field theory model for the tunneling. It is shown that the phenomenon of fermion number fractionalization is expe...
1994-05-26
2009-10-22
[ "cond-mat", "hep-th" ]
D. G. Barci and L. Moriconi
cond-mat/9405082
Possible Metal/Insulator Transition at B=0 in Two Dimensions
We have studied the zero magnetic field resistivity of unique high- mobility two-dimensional electron system in silicon. At very low electron density (but higher than some sample-dependent critical value, $n_{cr}\sim 10^{11}$ cm$^{-2}$), CONVENTIONAL WEAK LOCALIZATION IS OVERPOWERED BY A SHARP DROP OF RESISTIVITY BY AN...
1994-05-26
2009-10-22
[ "cond-mat" ]
S. V. Kravchenko, G. V. Kravchenko, J. E. Furneaux, V. M. Pudalov, and M. D'Iorio
cond-mat/9405077
Weak-Localization in Chaotic Versus Non-Chaotic Cavities: A Striking Difference in the Line Shape
We report experimental evidence that chaotic and non-chaotic scattering through ballistic cavities display distinct signatures in quantum transport. In the case of non-chaotic cavities, we observe a linear decrease in the average resistance with magnetic field which contrasts markedly with a Lorentzian behavior for a c...
1994-05-26
2009-10-22
[ "cond-mat" ]
A. M. Chang, H. U. Baranger, L. N. Pfeiffer, and K. W. West
cond-mat/9405071
Evidence for a Pseudogap Above the Critical Temperature in the Attractive Hubbard Model
We explore the effect of fluctuations for $T \geq T_c$ in the 2-D negative Hubbard model within the framework of the selfconsistent T-matrix formalism, which goes beyond the BCS approximation and includes pair fluctuations. We enter the regime where correlations are important, namely, $U/t = -4.0$, where $t$ denotes th...
1994-05-25
2016-08-14
[ "cond-mat" ]
J.J. Rodr\'iguez-N\'u\~nez, S. Schafroth, R. Micnas, T. Schneider, H. Beck and M.H. Pedersen
cond-mat/9405070
Competition of Phonons and Magnetic Interaction in One-Dimensional Fermion Systems
We consider a system of spin-dependent fermions on a one-dimensional lattice which is coupled to phonons. The phonons create either a Peierls instability by breaking the translational invariance or create long range correlations. On the other hand, there is a spin-dependent Hubbard-like interaction which competes with ...
1994-05-25
2019-08-17
[ "cond-mat" ]
D.Braak, F.Sievers and K.Ziegler
cond-mat/9405073
Partially Asymmetric Exclusion Process with Open Boundaries
Exclusive diffusion on a one-dimensional lattice is studied. In the model particles hop stochastically into both directions with different rates. At the ends of the lattice particles are injected and removed. The exact stationary probability measure is represented in form of a matrix product as a generalization of the ...
1994-05-25
2009-10-22
[ "cond-mat" ]
Sven Sandow
cond-mat/9405072
Nonlinear Susceptibility: A Direct Test of the Quadrupolar Kondo Effect in UBe(13)
We present the nonlinear susceptibility as a direct test of the quadrupolar Kondo scenario for heavy fermion behavior, and apply it to the case of cubic crystal-field symmetry. Within a single-ion model we compute the nonlinear susceptibility resulting from low-lying \Gamma_3 (5f^2 and Kramers (5f^3) doublets. We find ...
1994-05-25
2009-10-22
[ "cond-mat" ]
A.P. Ramirez (ATT), P. Chandra (NECI), P. Coleman (RUTGERS), Z.Fisk (LANL), J.L. Smith (LANL) and H.R. Ott (ETH)
cond-mat/9405065
Dynamic Magneto-Conductance Fluctuations and Oscillations in Mesoscopic Wires and Rings
Using a finite-frequency recursive Green's function technique, we calculate the dynamic magneto-conductance fluctuations and oscillations in disordered mesoscopic normal metal systems, incorporating inter-particle Coulomb interactions within a self-consistent potential method. In a disordered metal wire, we observe erg...
1994-05-24
2007-05-23
[ "cond-mat" ]
D.Z. Liu, Ben Yu-Kuang Hu, C. A. Stafford, and S. Das Sarma
cond-mat/9405069
Direct Calculation of Spin-Stiffness for Spin-1/2 Heisenberg Models
The spin-stiffness of frustrated spin-1/2 Heisenberg models in one and two dimensions is computed for the first time by exact diagonalizations on small clusters that implement spin-dependent twisted boundary conditions. Finite-size extrapolation to the thermodynamic limit yields a value of $0.14\pm 0.01$ for the spin-s...
1994-05-24
2009-10-22
[ "cond-mat" ]
J. Bonca, J.P. Rodriguez, J. Ferrer and K.S. Bedell
cond-mat/9405066
Statistics of the One-Electron Current in a One-Dimensional Mesoscopic Ring at Arbitrary Magnetic Fields
The set of moments and the distribution function of the one-electron current in a one-dimensional disordered ring with arbitrary magnetic flux are calculated.
1994-05-24
2009-10-22
[ "cond-mat", "hep-th" ]
A.S. Cattaneo, A. Gamba and I.V. Kolokolov
cond-mat/9405067
Vortices on "rail road tracks": A possible realization of random matrix ensemble
The thermodynamics of interacting vortices constricted to move in one-dimensional tracks carved out on superconducting film in the extreme type-II limit is mapped onto the Coulomd gas model of random matrices.
1994-05-24
2009-10-22
[ "cond-mat" ]
Y Chen and H J Jensen
cond-mat/9405068
Distribution function for shotnoise in disordered multi-channel quantum conductors
We obtain the shot noise generating function for a multi-channel quantum conductor in the diffusive limit.
1994-05-24
2007-05-23
[ "cond-mat" ]
K A Muttalib and Y Chen
cond-mat/9405061
Non-equilibrium noise in a mesoscopic conductor: microscopic analysis
Current fluctuations are studied in a mesoscopic conductor using non-equilibrium Keldysh technique. We derive a general expression for the fluctuations in the presence of a time dependent voltage, valid for arbitrary relation between voltage and temperature. Two limits are then treated: a pulse of voltage and a DC volt...
1994-05-23
2007-05-23
[ "cond-mat" ]
B. L. Altshuler, L. S. Levitov, and A. Yu. Yakovets
cond-mat/9405062
Saddle Points and Stark Ladders: Exact Calculations of Exciton Spectra in Superlattices
A new, exact method for calculating excitonic absorption in superlattices is described. It is used to obtain high resolution spectra showing the saddle point exciton feature near the top of the miniband. The evolution of this feature is followed through a series of structures with increasing miniband width. The Stark l...
1994-05-23
2009-10-22
[ "cond-mat" ]
D. M. Whittaker (Department of Physics, University of Sheffield, Sheffield. UK)
cond-mat/9405064
The mechanism of spin and charge separation in one dimensional quantum antiferromagnets
We reconsider the problem of separation of spin and charge in one dimensional quantum antiferromagnets. We show that spin and charge separation in one dimensional strongly correlated systems cannot be described by the slave boson or fermion representation within any perturbative treatment of the interactions between th...
1994-05-23
2009-10-22
[ "cond-mat", "hep-th" ]
C. Mudry and E. Fradkin
cond-mat/9405063
Exact Dynamical Correlation Functions of Calogero-Sutherland Model and One-Dimensional Fractional Statistics
One-dimensional model of non-relativistic particles with inverse-square interaction potential known as Calogero-Sutherland Model (CSM) is shown to possess fractional statistics. Using the theory of Jack symmetric polynomial the exact dynamical density-density correlation function and the one-particle Green's function (...
1994-05-23
2009-10-22
[ "cond-mat", "hep-th" ]
Z. N. C. Ha
cond-mat/9405060
On the theory of diamagnetism in granular superconductors
We study a highly disordered network of superconducting granules linked by weak Josephson junctions in magnetic field and develop a mean field theory for this problem. The diamagnetic response to a slow {\it variations} of magnetic field is found to be analogous to the response of a type-II superconductor with extremel...
1994-05-21
2009-10-22
[ "cond-mat" ]
M. V. Feigelman and L. B. Ioffe
cond-mat/9405059
Nonlinear Conductance for the Two Channel Anderson Model
Using the integral equations of the Noncrossing Approximation, the differential conductance is computed as a function of voltage for scattering from a two channel Kondo impurity in a point contact. The results compare well to experimental data on Cu point contacts by Ralph and Buhrman. They support a recently proposed ...
1994-05-21
2009-10-22
[ "cond-mat" ]
Matthias H. Hettler, Johann Kroha, and Selman Hershfield
cond-mat/9405057
The Fermi Edge Singularity and Boundary Condition Changing Operators
The boundary conformal field theory approach to quantum impurity problems is used to study the Fermi edge singularity, occuring in the X-ray adsorption probablility. The deep-hole creation operator, in the effective low-energy theory, changes the boundary condition on the conduction electrons. By a conformal mapping, t...
1994-05-20
2009-10-22
[ "cond-mat", "hep-th" ]
Ian Affleck and Andreas W.W. Ludwig
cond-mat/9405052
Statistics of Oscillator Strengths in Chaotic Systems
The statistical description of oscillator strengths for systems like hydrogen in a magnetic field is developed by using the supermatrix nonlinear $\sigma$-model. The correlator of oscillator strengths is found to have a universal parametric and frequency dependence, and its analytical expression is given. This universa...
1994-05-20
2009-10-22
[ "cond-mat" ]
Nobuhiko Taniguchi, A. V. Andreev and Boris L. Altshuler
cond-mat/9405053
Slave Boson Formulation for Interacting Boson Systems and the Superfluid-Insulator Transition
A new formulation for the study of interacting bosons on a lattice is introduced. This approach is used to give analytical expressions for the Mott insulating lobes in the phase diagram and to calculate the density-density correlation function. It is also shown that, at mean-field level, this newly introduced slave bos...
1994-05-20
2007-05-23
[ "cond-mat" ]
Raymond Fresard (Institut fuer Theorie der Kondensierten Materie, U. Karlsruhe)
cond-mat/9405055
Conductance and conductance fluctuations of narrow disordered quantum wires
In this paper we present and discuss our results for the conductance and conductance fluctuations of narrow quantum wires with two types of disorder: boundary roughness (hard wall confining potential) and islands of strongly scattering impurities within the bulk of the wire. We use a tight--binding Hamiltonian to descr...
1994-05-20
2009-10-22
[ "cond-mat" ]
K Nikoli\'c and A MacKinnon (Imperial College London)
cond-mat/9405058
A Superconducting Instability in the Infinite-U Anderson Lattice in the Presence of Crystal Electric Fields
We report evidence of a superconducting instability (of $T_{1g}$ symmetry) in the infinite-U Anderson lattice in the presence of crystal fields of cubic symmetry. We assume a lattice of $4f$ sites, each with a total angular momentum of $J=5/2$ that is split by crystal fields into a low-lying doublet of $\Gamma_7$ symme...
1994-05-20
2009-10-22
[ "cond-mat" ]
B. R. Trees
cond-mat/9405054
Solution of the two impurity, two channel Kondo Model
We solve the two-impurity two-channel Kondo model using a combination of conformal invariance and bosonisation techniques. The odd-even symmetric case is analysed in detail. The RKKY interaction turns out to be exactly marginal, resulting in a line of non-Fermi liquid fixed points. Explicit formulae are given for the c...
1994-05-20
2009-10-22
[ "cond-mat", "chao-dyn", "nlin.CD" ]
A.Georges and A.Sengupta
cond-mat/9405056
On the Thermodynamics of Laughlin Liquid Freezing
The competition between liquid and solid states of strongly correlated electron systems occurs in a novel way in a strong magnetic field. The fact that certain Landau level filling factors are especially favorable for the formation of strongly correlated liquid states, gives rise to the fractional quantum Hall effect. ...
1994-05-20
2007-05-23
[ "cond-mat" ]
Anthony Chan and A.H. MacDonald (Department of Physics, Indiana University, Bloomington IN)
cond-mat/9405051
AC Response of Flux-Line Liquid in High $T_c$ Superconductors
We use a hydrodynamics theory to discuss the response of a viscous flux-line liquid to an ac perturbation applied at the surface of the sample. The theory incorporates viscoelastic effects and describes the crossover between liquid-like and solid-like response of the vortex array as the frequency of the perturbation in...
1994-05-19
2009-10-22
[ "cond-mat" ]
Lee-Wen Chen, M. Cristina Marchetti (Dept. of Physics, Syracuse U.)
cond-mat/9405050
Observation of a van Hove Singularity in $Bi_{2}Sr_{2}Ca_{1}Cu_{2}O_{8+x}$ with Angle Resolved Photoemission
We have performed high energy resolution angle-resolved photoemission studies of the normal state band structure of oxygen overdoped $Bi_{2}Sr_{2}Ca_{1}Cu_{2}O_{8+x}$. We find that there is an extended saddle point singularity in the density of states along $\Gamma-\bar{M}-Z$ direction. The data also indicate that ther...
1994-05-18
2016-08-14
[ "cond-mat" ]
Jian Ma, C.Quitmann, R.J.Kelley, P.Alm\'eras, H.Berger, G. Margaritondo, and M.Onellion (Dept.of Phys. & ASC, UW-Madison and EPFL Switzerland)
cond-mat/9405049
Resistivity of the Two-Channel Kondo Model in Infinite Dimensions
Analytic results for the resistivity of the two-channel Kondo lattice in a particular infinite dimensional limit (Lorentzian density of states) are presented. It is argued that in the absence of symmetry breaking phase transitions or applied fields there is a residual resistivity at zero temperature due to the spin dis...
1994-05-17
2008-02-03
[ "cond-mat" ]
D.L. Cox (Ohio State)
cond-mat/9405046
Interacting Electrons on a Square Fermi Surface
Electronic states near a square Fermi surface are mapped onto quantum chains. Using boson-fermion duality on the chains, the bosonic part of the interaction is isolated and diagonalized. These interactions destroy Fermi liquid behavior. Non-boson interactions are also generated by this mapping, and give rise to a new p...
1994-05-17
2009-10-22
[ "cond-mat" ]
A. Luther
cond-mat/9405047
Critical Behaviour of the Randomly Spin--Diluted 2-d Ising Model --- A Grand Ensemble Approach
The critical behaviour of the randomly spin-diluted Ising model in two space dimensions is investigated by a new method which combines a grand ensemble approach to disordered systems proposed by Morita with the phenomenological renormalization group scheme of Nightingale. Accurate approximations for the phase diagram a...
1994-05-17
2009-10-22
[ "cond-mat", "hep-lat" ]
R. K\"uhn
cond-mat/9405048
Kinetic Inductance of Josephson Junction Arrays: Dynamic and Equilibrium Calculations
We show analytically that the inverse kinetic inductance $L^{-1}$ of an overdamped junction array at low frequencies is proportional to the admittance of an inhomogeneous equivalent impedance network. The $ij^{th}$ bond in this equivalent network has an inverse inductance $J_{ij}\cos(\theta_i^0-\theta_j^0-A_{ij})$, whe...
1994-05-17
2009-10-22
[ "cond-mat" ]
Wenbin Yu and D. Stroud
cond-mat/9405044
Optical absorption spectra of A6C60 and A6C70: Reduction of effective Coulomb interactions in Frenkel excitons
We theoretically investigate optical absorption spectra of $\soc^{6-}$ and $\rug^{6-}$, and discuss relations with the optical properties of alkali metal doped fullerides $A_6\soc$ and $A_6\rug$. This is a valid approach for systems where Frenkel exciton effects are dominant. We use a tight binding model with long rang...
1994-05-16
2007-05-23
[ "cond-mat", "chem-ph" ]
Kikuo Harigaya (Fundamental Physics Section, Electrotechnical Laboratory, Japan)
cond-mat/9405045
Spin Gaps in Coupled t-J Ladders
Spin gaps in coupled $t$-$J$ ladders are investigated by exact diagonalization of small clusters up to 4$\times$8 sites. At half-filling, the numerical results for the triplet excitation spectrum are in very good agreement with a second order perturbation expansion in term of small inter-ladder and intra-ladder exchang...
1994-05-16
2009-10-22
[ "cond-mat" ]
D. Poilblanc, H. Tsunetsugu, and T.M. Rice
cond-mat/9405043
Dynamical T=0 correlations of the S=1/2 1D Heisenberg Anti-Ferromagnet with 1/r^2 exchange in a magnetic field
We present a new selection rule for matrix elements of local spin operators in the $S=1/2$ ``Haldane-Shastry'' model. Based on this rule we extend a recent exact calculation \cite{H93} of the ground-state dynamical spin correlation function $S^{ab}(n,t)$ = $\langle 0 | S^a(n,t)S^b(0,0)| 0 \rangle$ and its Fourier-trans...
1994-05-14
2009-10-22
[ "cond-mat" ]
J.C. Talstra and F.D.M. Haldane
cond-mat/9405042
Non-equilibrium dynamics in the random bond Ising chain: A reminiscence of aging in spin glasses
Results of extensive Monte-Carlo simulations that investigate the out-of-equilibrium dynamics of the one-dimensional Ising spin glass model with a Gaussian bond-distribution are presented. At low enough temperatures a typical (interrupted) aging scenario is established as in two- and similar to three-dimensional spin g...
1994-05-14
2007-05-23
[ "cond-mat", "hep-lat" ]
H.Rieger J. Kisker and M.Schreckenberg
cond-mat/9405041
Intensity Distribution of Waves Transmitted Through a Multiple Scattering Medium
The distributions of the angular transmission coefficient and of the total transmission are calculated for multiple scattered waves. The calculation is based on a mapping to the distribution of eigenvalues of the transmission matrix. The distributions depend on the profile of the incoming beam. The distribution functio...
1994-05-13
2009-10-22
[ "cond-mat" ]
Th. M. Nieuwenhuizen and M. C. W. van Rossum
cond-mat/9405038
New Family of Solvable 1D Heisenberg Models
Starting from a Calogero--Sutherland model with hyperbolic interaction confined by an external field with Morse potential we construct a Heisenberg spin chain with exchange interaction $\propto 1/\sinh^2 x$ on a lattice given in terms of the zeroes of Laguerre polynomials. Varying the strength of the Morse potential th...
1994-05-13
2017-01-18
[ "cond-mat" ]
Holger Frahm and Vladimir I. Inozemtsev
cond-mat/9405037
Re-Structuring Method for the Negative Sign Problem in Quantum Spin Systems
We present detailed discussions on a new approach we proposed in a previous paper to numerically study quantum spin systems. This method, which we will call re-structuring method hereafter, is based on rearrangement of intermediate states in the path integral formulation. We observed our approach brings remarkable impr...
1994-05-13
2017-02-01
[ "cond-mat" ]
Tomo Munehisa and Yasuko Munehisa
cond-mat/9405040
Flame propagation in random media
We introduce a phase-field model to describe the dynamics of a self-sustaining propagating combustion front within a medium of randomly distributed reactants. Numerical simulations of this model show that a flame front exists for reactant concentration $c > c^* > 0$, while its vanishing at $c^*$ is consistent with mean...
1994-05-13
2009-10-22
[ "cond-mat" ]
N. Provatas, T. Ala-Nissila, Martin Grant, K. R. Elder, Luc Pich
cond-mat/9405036
Double-tip STM for Surface Analysis
We explore the possibility of using a double-tip STM to probe the single electron Green function of a sample surface, and describe a few important applications: (1) Probing constant energy surfaces in $\k$-space by ballistic transport; (2) Measuring scattering phase shifts of defects; (3) Observing the transition from ...
1994-05-13
2008-02-03
[ "cond-mat" ]
Q.Niu, M.C.Chang, and C.K.Shih
cond-mat/9405039
Superconductivity in the Two-Dimensional $t$-$J$ Model at Low Hole Doping
By combining a generalized Lanczos scheme with the variational Monte Carlo method we can optimize the short- and long-range properties of the groundstate separately. This allows us to measure the long-range order of the groundstate of the $t$-$J$ model as a function of the coupling constant $J/t$, and identify a region...
1994-05-13
2016-08-31
[ "cond-mat" ]
Elmar S. Heeb and T. Maurice Rice
cond-mat/9405034
Flow equations for the Anderson Hamiltonian
Using a continuous unitary transformation recently proposed by Wegner \cite{Wegner} together with an approximation that neglects irrelevant contributions, we obtain flow equations for Hamiltonians. These flow equations yield a diagonal or almost diagonal Hamiltonian. As an example we investigate the Anderson Hamiltonia...
1994-05-12
2009-10-22
[ "cond-mat" ]
Stephan Kehrein and Andreas Mielke
cond-mat/9405035
$\eta$-pairing as a mechanism of superconductivity in models of strongly correlated electrons
We consider extended versions of the Hubbard model which contain additional interactions between nearest neighbours. In this letter we show that a large class of these models has a superconducting ground state in arbitrary dimensions. In some special cases we are able to find the complete phase diagram. The superconduc...
1994-05-12
2009-10-22
[ "cond-mat", "hep-th" ]
Jan de Boer, Vladimir E. Korepin and Andreas Schadschneider
cond-mat/9405032
Excitonic Instability and Origin of the Mid-Gap States
In the framework of the two-band model of a doped semiconductor the self-consistent equations describing the transition into the excitonic insulator state are obtained for the 2D case. It is found that due to the exciton-electron interactions the excitonic phase may arise with doping in a semiconductor stable initially...
1994-05-11
2009-10-22
[ "cond-mat" ]
Michael N. Kiselev
cond-mat/9405033
Infrared Spectroscopic Study of Phase Transisions in A1c60 Compounds (a=K,Rb,Cs)
Optical measurements on doped C$_{60}$ films provide evidence for a transition from a high temperature conducting phase to a low temperature insulating phase in quenched Rb$_1$C$_{60}$ and K$_1$C$_{60}$ compounds, while Cs$_1$C$_{60}$ did not exhibit this behavior. For slow cooled samples our study confirms earlier res...
1994-05-11
2007-05-23
[ "cond-mat" ]
Daniel Koller, Michael C. Martin and Laszlo Mihaly
cond-mat/9405031
Reaction-Diffusion Processes Described by Three-State Quantum Chains and Integrability
The master equation of one-dimensional three-species reaction-diffusion processes is mapped onto an imaginary-time Schr\"odinger equation. In many cases the Hamiltonian obtained is that of an integrable quantum chain. Within this approach we search for all $3$-state integrable quantum chains whose spectra are known and...
1994-05-11
2009-10-22
[ "cond-mat" ]
Silvio R. Dahmen (University of Bonn)
cond-mat/9405027
Kosterlitz-Thouless Transition in Bi${}_2$Sr${}_2$CaCu${}_2$O${}_8+\delta$ Thin Films
Current-voltage ($I-V$) characteristics and the increase of superconducting transition temperature $T_c$ as a function of the number of half-unit-cell layers $n$ are studied on Bi${}_2$Sr${}_2$CaCu${}_2$O${}_{8+\delta}$ thin films grown by molecular beam epitaxy. These observations are interpreted in terms of Kosterlit...
1994-05-10
2008-02-03
[ "cond-mat" ]
Vortex String, Tomoko Ota, Ichiro Tsukada, Ichiro Terasaki, and Kunimitsu Uchinokura
cond-mat/9405026
Current-voltage characteristics of a tunnel junction with resonant centers
We calculate the I-V characteristics of a tunnel junction containing impurities in the barrier. We consider the indirect resonant tunneling involving the impurities. The Coulomb repulsion energy $E_c$ between two electrons with opposite spins simultaneously residing on the impurity is introduced by an Anderson Hamilton...
1994-05-10
2009-10-22
[ "cond-mat" ]
T. Ivanov, and V. Valtchinov
cond-mat/9405029
Propagation and Extinction in Branching Annihilating Random Walks
We investigate the temporal evolution and spatial propagation of branching annihilating random walks in one dimension. Depending on the branching and annihilation rates, a few-particle initial state can evolve to a propagating finite density wave, or extinction may occur, in which the number of particles vanishes in th...
1994-05-10
2009-10-22
[ "cond-mat" ]
Daniel ben-Avraham, Francois Leyvraz, and Sid Redner
cond-mat/9405030
Can Impurity Effects Help to Identify the Symmetry of the Order Parameter of the Cuprates?
The effects of non-magnetic impurities on the properties of superconductors with order parameters (OP) of different symmetry are discussed. In particular, we contrast the case of a d_{x^2 - y^2} with various forms of an anisotropic s-wave (ASW) gap. The biggest qualitative difference occurs if the phase of the s-wave O...
1994-05-10
2009-10-22
[ "cond-mat" ]
R. Fehrenbacher and M.R. Norman
cond-mat/9405025
Iterated perturbation theory for the attractive Holstein and Hubbard models
A strictly truncated (weak-coupling) perturbation theory is applied to the attractive Holstein and Hubbard models in infinite dimensions. These results are qualified by comparison with essentially exact Monte Carlo results. The second order iterated perturbation theory is shown to be quite accurate in calculating trans...
1994-05-10
2009-10-22
[ "cond-mat" ]
J. K. Freericks and Mark Jarrell
cond-mat/9405028
Explicit Solutions of the Bethe Ansatz Equations for Bloch Electrons in a Magnetic Field
For Bloch electrons in a magnetic field, explicit solutions are obtained at the center of the spectrum for the Bethe ansatz equations recently proposed by Wiegmann and Zabrodin. When the magnetic flux per plaquette is $1/Q$ where $Q$ is an odd integer, distribution of the roots is uniform on the unit circle in the comp...
1994-05-10
2009-10-22
[ "cond-mat", "hep-th" ]
Yasuhiro Hatsugai, Mahito Kohmoto, and Yong-Shi Wu
cond-mat/9405022
Magnetization of Disordered Ballistic Quantum Billards
We study the magnetic response of mesoscopic quantum dots in the ballistic regime where the mean free path $l_e$ is larger that the size $L$ of the sample, yet smaller than $L (k_F L)^{d-1}$. In this regime, disorder plays an important role. Employing a semiclassical picture we calculate the contribution of long trajec...
1994-05-09
2009-10-22
[ "cond-mat" ]
Daniel Braun, Yuval Gefen and Gilles Montambaux
cond-mat/9405024
One-Dimensional Kondo Lattice at Half Filling: Charge Properties
The model of Kondo chain with $M$-fold degenerate band of conduction electrons of spin 1/2 at half filling interacting with localized spins $S$ is studied. It is shown that due to the instanton effects the spin sector reveals itself in optical conductivity. Namely, the density of the charge current at large wave vector...
1994-05-09
2007-05-23
[ "cond-mat" ]
A. M. Tsvelik (University of Oxford)
cond-mat/9405018
Construction of transferable spherically-averaged electron potentials
A new scheme for constructing approximate effective electron potentials within density-functional theory is proposed. The scheme consists of calculating the effective potential for a series of reference systems, and then using these potentials to construct the potential of a general system. To make contact to the refer...
1994-05-09
2016-08-14
[ "cond-mat" ]
K. Stokbro, N. Chetty, K. W. Jacobsen, and J. K. N{\o}rskov
cond-mat/9405023
Asymmetric exclusion model for mixed ionic condustors
The ionic conductivity of mixed alkali glasses exhibits a deep minimum as a function of the relative concentrations of the two alkali ions. To study this behaviour we consider a simple one-dimensional model for asymmetric diffusion of two kinds of particles. Different particles are assumed to repulse each other. We con...
1994-05-09
2008-02-03
[ "cond-mat" ]
Sven Sandow, Steffen Trimper, David Mukamel
cond-mat/9405019
An Effective-Medium Tight-Binding Model for Silicon
A new method for calculating the total energy of Si systems is presented. The method is based on the effective-medium theory concept of a reference system. Instead of calculating the energy of an atom in the system of interest a reference system is introduced where the local surroundings are similar. The energy of the ...
1994-05-09
2016-08-14
[ "cond-mat" ]
K. Stokbro, N. Chetty, K. W. Jacobsen, and J. K. N{\o}rskov
cond-mat/9405021
Planar random networks with flexible fibers
The transition in random fiber networks from two-dimensional to three-dimensional planar structure driven by increasing coverage (total fiber length per unit area) is studied with a deposition model. At low coverage the network geometry depends on the scale-free product of fiber length and coverage while at high covera...
1994-05-09
2009-10-22
[ "cond-mat" ]
K.J. Niskanen and M.J. Alava
cond-mat/9405020
Nematogenic Lattice Models in One or Two Dimensions and with Long-Range Interactions
Extending previous rigorous results, we prove existence of an ordering transition at finite temperature for a class of nematogenic lattice models, where spins are associated with a one- or two-dimensional lattice, and interact via long-range potentials.
1994-05-09
2019-08-17
[ "cond-mat" ]
N. Angelescu, S. Romano, V.A. Zagrebnov
cond-mat/9405016
Generalized $t$-$j$ Model
By parameterizing the t-j model we present a new electron correlation model with one free parameter for high-temperature superconductivity. This model is of $SU_{q}(1,2)$ symmetry. The energy spectrums are shown to be modulated by the free parameter in the model. The solution and symmetric structures of the Hilbert spa...
1994-05-06
2009-10-22
[ "cond-mat", "hep-th" ]
Shao-Ming Fei and Rui-Hong Yue
cond-mat/9405015
On the Formation of Transient (Na$_{19}$)$_2$ and (Na$_{20}$)$_2$ Cluster Dimers from Molecular Dynamics Simulations
By using tight binding molecular dynamics simulations, we discuss the possibilities to form (Na$_{19}$)$_2$ and (Na$_{20}$)$_2$ cluster dimers in sodium cluster collisions. In the case of Na$_{19}$ + Na$_{19}$, we show that the formation of a prolate dimer-like (Na$_{19}$)$_2$ maybe depend on the initial relative orien...
1994-05-06
2009-10-22
[ "cond-mat" ]
F.S. Zhang, F. Spiegelmann, E. Suraud, V. Fraysse, R. Poteau, R. Glowinski and F. Chatelin
cond-mat/9405013
Exact Solution of a One-Dimensional Multicomponent Lattice Gas with Hyperbolic Interaction
We present the exact solution to a one-dimensional multicomponent quantum lattice model interacting by an exchange operator which falls off as the inverse-sinh-square of the distance. This interaction contains a variable range as a parameter, and can thus interpolate between the known solutions for the nearest-neighbor...
1994-05-06
2016-08-14
[ "cond-mat" ]
Bill Sutherland, Rudolf A. R\"omer and B. Sriram Shastry
cond-mat/9405017
Exclusion Statistics: Low-Temperature Properties, Fluctuations, Duality, Applications
We derive some physical properties of ideal assemblies of identical particles obeying generalized exclusion statistics. We discuss fluctuations, and in this connection point out a fundamental contrast to conventional quantum statistics. We demonstrate a duality relating the distribution of particles at statistics $g$ t...
1994-05-06
2008-02-03
[ "cond-mat" ]
Frank Wilczek and Chetan Nayak
cond-mat/9405012
Critical behavior of nonequilibrium models with infinitely many absorbing states
I study the critical behavior of a two-dimensional dimer-trimer lattice model, introduced by K\"{o}hler and ben-Avraham [J. Phys. A {\bf 24}, L621 (1991)], for heterogeneous catalysis of the reaction $\frac{1}{2}A_{2}+\frac{1}{3}B_{3} \rightarrow AB$. The model possesses infinitely many absorbing states in which the la...
1994-05-06
2015-06-25
[ "cond-mat" ]
Iwan Jensen
cond-mat/9405014
Effect of the Coulomb repulsion on the {\it ac} transport through a quantum dot
We calculate in a linear response the admittance of a quantum dot out of equilibrium. The interaction between two electrons with opposite spins simultaneously residing on the resonant level is modeled by an Anderson Hamiltonian. The electron correlations lead to the appearence of a new feature in the frequency dependen...
1994-05-06
2009-10-22
[ "cond-mat" ]
T. Ivanov, V. Valtchinov, and L. T. Wille
cond-mat/9405011
Exotic and conventional superconductivity in a Dirac supersymmetric scheme
A new pairing theory for many-fermion systems is obtained via the Dirac supersymmetry framework recently introduced to describe Dirac particles in external potentials. It is shown that the standard Bogoliubov-Valatin canonical transformation treatment of the quasi-particle BCS singlet pairing mechanism naturally falls ...
1994-05-05
2016-08-14
[ "cond-mat", "hep-th" ]
M. Moreno, R. M. M\'endez-Moreno, S. Orozco and M. A. Ort\'iz and M. de Llano
cond-mat/9405007
Interfaces and Lower Critical Dimension in a Spin Glass Model
In this paper we try to estimate the lower critical dimension for replica symmetry breaking in spin glasses through the calculation of the additional free-energy required to create a domain wall between two different phases. This mechanism alone would say that replica symmetry would be restored at the lower critical di...
1994-05-04
2009-10-22
[ "cond-mat" ]
S. Franz, G. Parisi, M.A. Virasoro
cond-mat/9405008
Scaling laws and simulation results for the self--organized critical forest--fire model
We discuss the properties of a self--organized critical forest--fire model which has been introduced recently. We derive scaling laws and define critical exponents. The values of these critical exponents are determined by computer simulations in 1 to 8 dimensions. The simulations suggest a critical dimension $d_c=6$ ab...
1994-05-04
2009-10-22
[ "cond-mat" ]
S. Clar, B. Drossel, and F. Schwabl
cond-mat/9405010
Conductance Distributions in Random Resistor Networks: Self Averaging and Disorder Lengths
The self averaging properties of conductance $g$ are explored in random resistor networks with a broad distribution of bond strengths $P(g)\simg^{\mu-1}$. Distributions of equivalent conductances are estimated numerically on hierarchical lattices as a function of size $L$ and distribution tail parameter $\mu$. For netw...
1994-05-04
2009-10-22
[ "cond-mat" ]
R. F. Angulo and E. Medina
cond-mat/9405006
Critical Exponents for Branching Annihilating Random Walks with an Even Number of Offspring
Recently, Takayasu and Tretyakov [Phys. Rev. Lett. {\bf 68}, 3060 (1992)], studied branching annihilating random walks (BAW) with $n=1$-5 offspring. These models exhibit a continuous phase transition to an absorbing state. For odd $n$ the models belong to the universality class of directed percolation. For even $n$ the...
1994-05-04
2009-10-22
[ "cond-mat" ]
Iwan Jensen
cond-mat/9405009
Tricritical behavior of the frustrated XY antiferromagnet
Extensive histogram Monte-Carlo simulations of the XY antiferromagnet on a stacked triangular lattice reveal exponent estimates which strongly favor a scenario of mean-field tricritical behavior for the spin-order transition. The corresponding chiral-order transition occurs at the same temperature but appears to be dec...
1994-05-04
2009-10-22
[ "cond-mat" ]
M.L. Plumer, A. Mailhot, and A. Caill\'e (Centre de Recherche en Physique du Solide et D\'epartement de Physique, Universit\'e de Sherbrooke, Sherbrooke, Qu\'ebec, Canada)
cond-mat/9405003
Scaling and Crossover in the Large-N Model for Growth Kinetics
The dependence of the scaling properties of the structure factor on space dimensionality, range of interaction, initial and final conditions, presence or absence of a conservation law is analysed in the framework of the large-N model for growth kinetics. The variety of asymptotic behaviours is quite rich, including sta...
1994-05-03
2009-10-22
[ "cond-mat" ]
Antonio Coniglio, Patrizia Ruggiero and Marco Zannetti
cond-mat/9405004
Tunneling and the Band Structure of Chaotic Systems
We compute the dispersion laws of chaotic periodic systems using the semiclassical periodic orbit theory to approximate the trace of the powers of the evolution operator. Aside from the usual real trajectories, we also include complex orbits. These turn out to be fundamental for a proper description of the band structu...
1994-05-03
2009-10-22
[ "cond-mat", "chao-dyn", "nlin.CD" ]
P. Leboeuf & A. Mouchet
cond-mat/9405005
Electron-Electron Interactions and the Hall-Insulator
Using the Kubo formula, we show explicitly that a non-interacting electron system can not behave like a Hall-insulator, {\it ie.,} a DC resistivity matrix $\rho_{xx}\rightarrow\infty$ and $\rho_{xy}=$finite in the zero temperature limit, as has been observed recently in experiment. For a strongly interacting electron s...
1994-05-03
2009-10-22
[ "cond-mat" ]
Lian Zheng, and H.A. Fertig
cond-mat/9405001
Comment on "Evolution from BCS Superconductivity to Bose-Einstein Condensation: Role of the Parameter $k_{\rm F} \xi$ in Interpreting the Experimental Plot by Uemura et al.''}
The problem of crossover from BCS to Bose-Einstein condensation has recently attracted considerable interest owing to the discovery of high-$T_{\rm c}$ cuprates. Their short coherence length, $\xi$, places these materials in the interesting region between BCS and Bose-Einstein condensation. In the paper of F. Pistolesi...
1994-05-02
2016-08-16
[ "cond-mat" ]
J.J. Rodr\'iguez-N\'u\~nez, S. Schafroth, T. Schneider, M.H. Pedersen and C. Rossel
cond-mat/9405002
Metal-insulator and insulator-insulator transitions in the quarter-filled band organic conductors
The theory of the 2k_F and 4k_F instabilities in quarter-filled band organic conductors is revisited. The phase angles of the 2k_F bond and charge density waves are shown to change as electron correlation is turned on, and this switching of the phase angle is critical for understanding the bond distortion patterns in t...
1994-05-02
2009-10-22
[ "cond-mat" ]
K.C. Ung, S. Mazumdar, and D.Toussaint
cond-mat/9404101
Manifolds in random media: A variational approach to the spatial probability distribution
We develop a new variational scheme to approximate the position dependent spatial probability distribution of a zero dimensional manifold in a random medium. This celebrated 'toy-model' is associated via a mapping with directed polymers in 1+1 dimension, and also describes features of the commensurate-incommensurate ph...
1994-05-02
2009-10-22
[ "cond-mat" ]
Yadin Y. Goldschmidt
cond-mat/9404100
The Density Matrix Renormalization Group for Fermion Systems
We discuss techniques of the density matrix renormalization group and their application to interacting fermion systems in more than one dimension. We show numerical results for equal--time spin--spin and singlet pair field correlation functions, as well as the spin gap for the Hubbard model on two chains. The system is...
1994-04-30
2007-05-23
[ "cond-mat" ]
R.M. Noack, S.R. White, and D.J. Scalapino
cond-mat/9404098
Energy cost associated with vortex crossing in superconductors
Starting from the Ginzburg-Landau free energy of a type II superconductor in a magnetic field we estimate the energy associated with two vortices crossing. The calculations are performed by assuming that we are in a part of the phase diagram where the lowest Landau level approximation is valid. We consider only two vor...
1994-04-29
2009-10-22
[ "cond-mat" ]
M.A. Moore and N.K. Wilkin
cond-mat/9404099
Quantumdots
Atomic-like systems in which electronic motion is two dimensional are now realizable as ``quantum dots''. In place of the attraction of a nucleus there is a confining potential, usually assumed to be quadratic. Additionally, a perpendicular magnetic field $B$ may be present. We review some recent rigorous results for t...
1994-04-29
2007-05-23
[ "cond-mat" ]
E. H. Lieb, J. P. Solovej and J. Yngvason
cond-mat/9404096
Thermodynamics of an one-dimensional ideal gas with fractional exclusion statistics
We show that the particles in the Calogero-Sutherland Model obey fractional exclusion statistics as defined by Haldane. We construct anyon number densities and derive the energy distribution function. We show that the partition function factorizes in the form characteristic of an ideal gas. The virial expansion is exac...
1994-04-29
2009-10-22
[ "cond-mat" ]
M.V.N.Murthy and R.Shankar
cond-mat/9404097
Numerical Renormalization Group Study of Pseudo-Fermion and Slave-Boson Spectral Functions in the Single Impurity Anderson Model
We use the numerical renormalization group to calculate the auxiliary spectral functions of the $U=\infty$ Anderson impurity model. The slave--boson and pseudo--fermion spectral functions diverge at the threshold with exponents $\alpha_{b}$ and $\alpha_{f}$ given in terms of the conduction electron phase shifts by the ...
1994-04-29
2009-10-22
[ "cond-mat" ]
T. A. Costi, P. Schmitteckert, J. Kroha and P. Woelfle
cond-mat/9404090
A microscopic approach to the dimerization in the frustrated spin-1/2 antiferromagnetic chains
The spontaneous dimerization of the frustrated spin-$1\over2$ antiferromagnetic chains is studied by a microscopic approach based on a proper set of composite operators (i.e., pseudo-spin operators). Two approximation schemes are developed. Firstly, a spin-wave approximation is made by a Dyson-Mal\'eev-like boson trans...
1994-04-28
2009-10-22
[ "cond-mat" ]
Yang Xian
cond-mat/9404092
Binding of Holes to Magnetic Impurities in a Strongly Correlated System
The effect of a magnetic (S=1/2) impurity coupled to a 2D system of correlated electrons (described by the t--J model) is studied by exact diagonalisations. It is found that, if the exchange coupling of the impurity with the neighboring spins is ferromagnetic or weakly antiferromagnetic, an extra hole can form bound st...
1994-04-28
2016-08-31
[ "cond-mat" ]
D. Poilblanc, D. J. Scalapino, and W. Hanke
cond-mat/9404093
Dynamics of N-spins Quantum Ferromagnet with Uniform Exchange: Exact Solution
The transverse spin autocorrelation function at an arbitrary temperature are calculated rigorously for the system of $N$ uniformly exchanged quantum spins. At large $N$ the correlator in the para-phase is found to have a Gaussian bump at small times and a non vanishing tail at large times. A possible application of tho...
1994-04-28
2007-05-23
[ "cond-mat" ]
M. Chertkov and I. Kolokolov
cond-mat/9404095
t-J model Studied by the New Lanczos-Power Method
The initial trial wave function used in a simple ground-state projection method, the power method, is systematically improved by using Lanczos algorithm. Much faster convergence to the ground state achieved by using these wave functions significantly reduces the effect of the fermion sign problem. The energy, spin and ...
1994-04-28
2009-10-22
[ "cond-mat" ]
Y. C. Chen and T. K. Lee