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Condensed Matter papers — page 223

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Two-hole problem in the t-J model: A canonical transformation approach
The t-J model in the spinless-fermion representation is studied. An effective Hamiltonian for the quasiparticles is derived using canonical transformation approach. It is shown that the rather simple…
V. I. Belinicher, A. L. Chernyshev, V. A. ShubinNov 1, 1996
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Density Waves in a Transverse Electric Field
In a quasi-one-dimensional conductor with an open Fermi surface, a Charge or a Spin Density Wave phase can be destroyed by an electric field perpendicular to the direction of high conductivity. This…
Gilles MontambauxOct 31, 1996
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A Monte Carlo Renormalization Group Approach to the Bak-Sneppen model
A recent renormalization group approach to a modified Bak-Sneppen model is discussed. We propose a self-consistency condition for the blocking scheme to be essential for a successful RG-method…
Bernhard MikeskaOct 31, 1996
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Extended Aharonov-Bohm period analysis of strongly correlated electron systems
The `extended Aharonov-Bohm (AB) period' recently proposed by Kusakabe and Aoki [J. Phys. Soc. Jpn (65), 2772 (1996)] is extensively studied numerically for finite size systems of strongly correlated…
Ryotaro Arita, Koichi Kusakabe, Kazuhiko Kuroki et al.Oct 29, 1996
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Wigner Function Description of the A.C.-Transport Through a Two-Dimensional Quantum Point Contact
We have calculated the admittance of a two-dimensional quantum point contact (QPC) using a novel variant of the Wigner distribution function (WDF) formalism. In the semiclassical approximation, a…
Igor E. Aronov, Gennady P. Berman, David K. Campbell et al.Oct 29, 1996
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Hydrodynamic modes in a trapped Bose gas above the Bose-Einstein transition
We discuss the collective modes of a trapped Bose gas in the hydrodynamic regime where atomic collisions ensure local thermal equilibrium for the distribution function. Starting from the conservation…
A. Griffin, Wen-Chin Wu, S. StringariOct 25, 1996
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Alternate route to soliton solutions in hydrogen-bonded chains
In this paper we offer an alternate route for investigating soliton solutions in hydrogen-bonded chains. This is done by examining a class of systems of two coupled real scalar fields. We show that…
D. Bazeia, J. R. S. Nascimento, D. ToledoOct 25, 1996
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Two interacting Hofstadter butterflies
The problem of two interacting particles in a quasiperiodic potential is addressed. Using analytical and numerical methods, we explore the spectral properties and eigenstates structure from the weak…
Armelle Barelli, Jean Bellissard, Philippe Jacquod et al.Oct 25, 1996
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Weakly nonlinear quantum transport: an exactly solvable model
We have studied the weakly non-linear quantum transport properties of a two-dimensional quantum wire which can be solved exactly. The non-linear transport coefficients have been calculated and…
Jian Wang, Qingrong Zheng, Hong GuoOct 25, 1996
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Stability of optically-active charged excitons in quasi-two dimensional systems
A negatively charged quasi-two dimensional exciton (X-) is solved exactly numerically in the presence of a uniform perpendicular B-field. Various quasi-two dimensional geometries are studied. The…
James R. Chapman, Neil F. Johnson, V. Nikos NicopoulosOct 24, 1996
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Relaxation dynamics of multi-level tunneling systems
A quantum mechanical treatment of an asymmetric double-well potential (DWP) interacting with a heat bath is presented for circumstances where the contribution of higher vibrational levels to the…
P. Neu, A. HeuerOct 24, 1996
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Temperature and magnetic field dependence of the lattice constant in spin-Peierls cuprate CuGeO3 studied by capacitance dilatometry in fields up to 16 Tesla
We present high resolution measurements of the thermal expansion coefficient and the magnetostriction along the a-axis of CuGeO3 in magnetic fields up to 16 Tesla. From the pronounced anomalies of…
T. Lorenz, U. Ammerahl, T. Auweiler et al.Oct 23, 1996
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Room Temperature Molecular Single-Electron Transistor
A room temperature single-electron transistor based on the single cluster molecule has been demonstrated for the first time. Scanning tunneling microscope tip was used to study the transport via…
E. S. Soldatov, V. V. Khanin, A. S. Trifonov et al.Oct 22, 1996
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Thermodynamic Properties of the Incommensurate Phase of CuGeO3
We present high resolution measurements of the specific heat and the thermal expansion of the inorganic spin--Peierls cuprate CuGeO3 in a magnetic field of 16 Tesla. At the transition from the…
T. Lorenz, U. Ammerahl, R. Ziemes et al.Oct 22, 1996
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Percolation mechanism for Colossal Magnetoresistance
We argue that colossal magnetoresistance is a critical phenomenon and propose a mechanism to describe it. The mechanism relies on the halfmetallic behavior of the materials showing colossal…
Paul J. M. Bastiaansen, Hubert J. F. KnopsOct 22, 1996
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Critical Adsorption in Systems with Weak Surface Field: The Renormalization-Group Approach
We study the surface critical behavior of semi-infinite systems belonging to the bulk universality class of the Ising model. Special attention is paid to the local behavior of experimentally relevant…
A. Ciach, U. RitschelOct 22, 1996
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Diffusion and localization in chaotic billiards
We study analytically and numerically the classical diffusive process which takes place in a chaotic billiard. This allows to estimate the conditions under which the statistical properties of…
Fausto Borgonovi, Giulio Casati, Baowen LiOct 22, 1996
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A new experimental procedure for characterizing quantum effects in small magnetic particle systems
A new experimental procedure is discussed, which aims at separating thermal from quantum behavior independently of the energy barrier distribution in small particle systems. Magnetization relaxation…
R. Sappey, E. Vincent, M. Ocio et al.Oct 17, 1996
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Particle propagation in a random and quasiperiodic potential
We numerically investigate the Anderson transition in an effective dimension d (3 ≤ d ≤ 11) for one particle propagation in a model random and quasiperiodic potential. The found critical…
F. Borgonovi, D. L. ShepelyanskyOct 17, 1996
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Spin fluctuations in CuGeO3 probed by light scattering
We have measured temperature dependence of low-frequency Raman spectra in CuGeO3, and have observed the quasi-elastic scattering in the (c,c) polarization above the spin-Peierls transition…
Haruhiko Kuroe, Jun-ichi Sasaki, Tomoyuki Sekine et al.Oct 17, 1996
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Scattering approach to classical quasi-1D transport
General dynamical transport of classical particles in disordered quasi-1D samples is viewed in the framework of scattering approach. Simple equation for the transfer-matrix is obtained within this…
Eugene KoganOct 16, 1996
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Low Temperature Properties of Quantum Antiferromagnetic Chains with Alternating Spins S=1 and 1/2
We study the low-temperature properties of S=1 and 1/2 alternating spin chains with antiferromagnetic nearest-neighbor exchange couplings using analytical techniques as well as a quantum Monte Carlo…
S. Brehmer, H. -J. Mikeska, S. YamamotoOct 14, 1996
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Finite Size Scaling for Low Energy Excitations in Integer Heisenberg Spin Chains
In this paper we study the finite size scaling for low energy excitations of S=1 and S=2 Heisenberg chains, using the density matrix renormalization group technique. A crossover from 1/L…
Shaojin Qin, Yu-Liang Liu, Lu YuOct 11, 1996
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Matrix product states approach to the Heisenberg ferrimagnetic spin chains
We propose a new version of the matrix product (MP) states approach to the description of quantum spin chains, which allows one to construct MP states with certain total spin and its z-projection. We…
A. K. Kolezhuk, H. -J. Mikeska, Shoji YamamotoOct 11, 1996
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The two dimensional antiferromagnetic Heisenberg model in the presence of an external field
We present numerical results on the zero temperature magnetization curve and the static structure factors of the two dimensional antiferromagnetic Heisenberg model in the presence of an external…
M S Yang, K H MütterOct 10, 1996
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