8,647 research outputs found
Ground-state properties of the One-dimensional Kondo Lattice at partial Band-filling
We compute the magnetic structure factor, the singlet correlation function
and the momentum distribution of the one-dimensional Kondo lattice model at the
density . The density matrix-renormalization group method is used.
We show that in the weak-coupling regime, the ground state is paramagnetic. We
argue that a Luttinger liquid description of the model in this region is
consistent with our calculations . In the strong-coupling regime, the ground
state becomes ferromagnetic. The conduction electrons show a spinless-fermion
like behavior.Comment: 8 pages, Latex, 5 figures included, to be published in PRB (Rapid
Communications
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 . We confirm the existence of a critical spin-phonon coupling for the onset of the spin gap bearing the signature of
a Kosterlitz-Thouless transition. We also observe a classical-quantum crossover
when the spin-Peierls gap is of order . In the classical
regime, , the mean-field parameters are strongly renormalized
by non-adiabatic corrections. This is the first application of the DMRG to
phonons.Comment: 10 pages, 5 figures. To be published in PR
A mucus model to evaluate the diffusion of drugs for more efficient cystic fibrosis therapies
Fermi Surface of The One-dimensional Kondo Lattice Model
We show a strong indication of the existence of a large Fermi surface in the
one-dimensional Kondo lattice model. The characteristic wave vector of the
model is found to be , being the density of the
conduction electrons. This result is at first obtained for a variant of the
model that includes an antiferromagnetic Heisenberg interaction between
the local moments. It is then directly observed in the conventional Kondo
lattice , in the narrow range of Kondo couplings where the long
distance properties of the model are numerically accessible.Comment: 11 pages, 6 figure
Genetic heterogeneity of hepatitis E virus in Darfur, Sudan, and neighboring Chad.
The within-outbreak diversity of hepatitis E virus (HEV) was studied during the outbreak of hepatitis E that occurred in Sudan in 2004. Specimens were collected from internally displaced persons living in a Sudanese refugee camp and two camps implanted in Chad. A comparison of the sequences in the ORF2 region of 23 Sudanese isolates and five HEV samples from the two Chadian camps displayed a high similarity (>99.7%) to strains belonging to Genotype 1. But four isolates collected in one of the Chadian camps were close to Genotype 2. Circulation of divergent strains argues for possible multiple sources of infection
Density Matrix Renormalization Group Study of One-Dimensional Acoustic Phonons
We study the application of the density matrix renormalization group (DMRG)
to systems with one-dimensional acoustic phonons. We show how the use of a
local oscillator basis circumvents the difficulties with the long-range
interactions generated in real space using the normal phonon basis. When
applied to a harmonic atomic chain, we find excellent agreement with the exact
solution even when using a modest number of oscillator and block states (a few
times ten). We discuss the use of this algorithm in more complex cases and
point out its value when other techniques are deficient.Comment: 12 pages. To be published in PRB rapid co
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