Thermodynamic and statistical properties of charged topological defects

2002 ◽  
Vol 12 (9) ◽  
pp. 235-236
Author(s):  
S. Teber
Keyword(s):  
Domain Walls ◽  
Density Wave ◽  
Topological Defects ◽  
Statistical Properties ◽  
Dimensional System ◽  
Coulomb Interactions ◽  
One Dimensional ◽  
Long Range Interactions ◽  
Component Plasma ◽  
Stripe Phases

We focus on the statistical and thermodynamic properties of systems with competing long-range interactions. The studies are based on the physics of quasi-one dimensional system with special interest towards their topological defects, the so-called solitons. We have been considering ensembles of solitons resulting from the degeneracy of the ground state of the system. This is the case of various charge density-wave systems such as polyacetylene-like polymers where the solitons are the non-trivial excitations connecting different ground-states. We have been interested in particular with a one component plasma with $3D$ Coulomb interactions of such defects, mainly in 2 space dimensions. The $3D$ case has also been considered. The quasi-one dimensional nature of the system is responsible for the confinement of the solitons. This competition between confinement and Coulomb has been formulated and some of its non-trivial effects analyaed. This led us to study the statistical properties of charged interfaces: strings or domain walls in $3D$. We have found that shape instabilities, due to the competing interactions, play a fundamental role. The obtained results show similarities with experimental work in the field of stripe phases in cuprate oxides.

AGING IN A ONE-DIMENSIONAL EDWARDS–ANDERSON SPIN GLASS MODEL WITH LONG-RANGE INTERACTIONS

2003 ◽  
Vol 14 (03) ◽  
pp. 257-265 ◽  
Author(s):  
MARCELO A. MONTEMURRO ◽  
FRANCISCO A. TAMARIT
Keyword(s):  
Long Range ◽  
Nearest Neighbor ◽  
Dynamical Behavior ◽  
Mean Field ◽  
Dimensional System ◽  
One Dimensional ◽  
Long Range Interactions ◽  
Glass Model ◽  
The One ◽  
Aging Phenomena

In this work we study, by means of numerical simulations, the out-of-equilibrium dynamics of the one-dimensional Edwards–Anderson model with long-range interactions of the form ± Jr-α. In the limit α → 0 we recover the well known Sherrington–Kirkpatrick mean-field version of the model, which presents a very complex dynamical behavior. At the other extreme, for α → ∞ the model converges to the nearest-neighbor one-dimensional system. We focus our study on the dependence of the dynamics on the history of the sample (aging phenomena) for different values of α. The model is known to have mean-field exponents already for values of α = 2/3. Our results indicate that the crossover to the dynamic mean-field occurs at a value of α < 2/3.

scholarly journals ORDERING FROM FRUSTRATION IN A STRONGLY CORRELATED ONE-DIMENSIONAL SYSTEM

2009 ◽  
Vol 23 (18) ◽  
pp. 3687-3708
Author(s):  
SIDDHARTHA LAL ◽  
MUKUL S. LAAD
Keyword(s):  
Phase Diagram ◽  
Quantum Critical Point ◽  
Ground States ◽  
Charge Order ◽  
Dimensional System ◽  
Dimensional Crossover ◽  
Coulomb Interactions ◽  
One Dimensional ◽  
Spin Order ◽  
Quantum Critical

We study a one-dimensional extended Hubbard model with longer-range Coulomb interactions at quarter-filling in the strong coupling limit. We find two different charge-ordered (CO) ground states (Wigner and Peierls) as the strength of the longer range interactions is varied. At lower energies, the two CO states drive different spin-ordered ground states (Heisenberg antiferromagnet and dimerised respectively), reminiscent of the phase diagram of the TMTTF and TMTSF organic charge transfer salts. Several response functions computed in the quantum critical regime bear a remarkable resemblance to recent experimental observations related to CO in the organic TMTTF systems. RPA studies of coupled chains reveal a phase diagram with the ordered phase extended to finite temperatures and a phase boundary ending at a quantum critical point (QCP). Critical quantum fluctuations at the QCP enhance the transverse dispersion, leading to a dimensional crossover and a T = 0 deconfinement transition from insulating chains to anisotropic metallic planar behavior. Numerical estimates for the hierarchy of energy scales associated with charge and spin order and the dimensional crossover compare well with the values obtained experimentally. This leads us to propose that the TMTTF and TMTSF systems are proximate to a QCP associated with T = 0 charge order.

Simulation of a charge-density-wave transition in a quasi-one-dimensional system

1986 ◽  
Vol 34 (9) ◽  
pp. 6367-6371 ◽  
Author(s):  
D. J. Scalapino ◽  
R. L. Sugar ◽  
W. D. Toussaint
Keyword(s):  
Charge Density ◽  
Charge Density Wave ◽  
Density Wave ◽  
Dimensional System ◽  
One Dimensional ◽  
A Charge

Fermi surface and photoemission lineshape of incommensurate CDW systems

2000 ◽  
Vol 14 (29n31) ◽  
pp. 3679-3684 ◽  
Author(s):  
G. Seibold ◽  
C. Castellani ◽  
C. Di Castro ◽  
M. Grilli
Keyword(s):  
Fermi Surface ◽  
Density Wave ◽  
Surface States ◽  
Leading Edge ◽  
Spectral Weight ◽  
Dimensional Structure ◽  
Coulomb Interactions ◽  
One Dimensional ◽  
Particle Spectra ◽  
Charge Modulation

We study the single-particle spectra of a model which shows an incommensurate charge-density wave (CDW) instability arising from the competition between phase separation and long-range Coulomb interactions. Starting from an open Fermi surface we find that the resulting CDW is oriented along the (1,0)- and (or) (0,1)-direction which (besides a purely one-dimensional structure) allows for a two-dimensional "eggbox type" charge modulation. This leads to a substantial enhancement of the van Hove singularities and the spectral weight of Fermi surface states near the M-points tends to be suppressed. Remarkably, a leading edge gap arises near these points, which, in the eggbox case, leaves finite arcs of the Fermi surface gapless. Extending this approach to the inclusion of dynamic incommensurate CDW fluctuations in the superconducting state we calculate the photoemission lineshape which agrees well with experimental data of underdoped Bi2212 compounds.

scholarly journals ANISOTROPY IN THE COMPRESSIBLE QUANTUM HALL STATE

2001 ◽  
Vol 15 (10n11) ◽  
pp. 1373-1376
Author(s):  
NOBUKI MAEDA
Keyword(s):  
Mean Field Theory ◽  
Density Wave ◽  
Quantum Hall ◽  
Mean Field ◽  
Dimensional System ◽  
Von Neumann ◽  
One Dimensional ◽  
Hartree Fock ◽  
Fermion Systems ◽  
Lattice Fermion

Using a mean field theory on the von Neumann lattice, we study compressible anisotropic states around ν=l+1/2 in the quantum Hall system. The Hartree-Fock energy of the unidirectional charge density wave (UCDW) are calculated self-consistently. In these states the UCDW seems to be the most plausible state. We show that the UCDW is regarded as a collection of the one-dimensional lattice fermion systems which extend to the uniform direction. The kinetic energy of this one-dimensional system is induced from the Coulomb interaction term and the self-consistent Fermi surface is obtained.

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