Many-body properties of one-dimensional systems with contact interaction
Author
Demirel, Ekrem
Advisor
Tanatar, Bilal
Date
1999Publisher
Bilkent University
Language
English
Type
ThesisItem Usage Stats
85
views
views
26
downloads
downloads
Abstract
The one-dimensional electron systems are attracting a lot of interest because
of theoretical and technological implications. These systems are usually
fabricated on two-dimensional electron systems by confining the electrons in one
of the remaining free directions by using nanolithographic techniques. There
are also naturally occuring orgnanic conductors such as TTF-TCNQ whose
conductivity is thought to be largely one-dimensional. The one-dimensional
electron systems are important theoretically since they constitute one of the
simplest many-body systems of interacting fermions with properties very different
from three- and two-dimensional systems. The one-dimensional electron gas with
a repulsive contact interaction model can be a useful paradigm to investigate these
peculiar many-body properties.
The system of bosons are also very interesting because of the macroscopic
effects such as Bose-Einstein condensation and superfluidity. Another motivation
to study one-dimensional Bose gas is the theoretical thought that one-dimensional
electron gas gives boson gas characteristics. This work is based on the
study of correlation effects in one-dimensional electron and boson gases with repulsive contact interactions. The correlation effects are described by a localfield
correction which takes into account the short-range correlations. We
use Vashishta-Singwi approach to calculate static correlation effects in onedimensional
electron and boson gases. We find that Vashishta-Singwi approach
gives better results than the other approximations.
We also study the dynamical correlation effects in a one-dimensional electron
gas with contact interaction within the quantum version of the self-consistent
scheme of Singwi et al. (STLS) We calculate frequency dependent local-field
corrections for both density and spin fluctuations. We investigate the structure
factors, spin-dependent pair-correlation functions, and collective excitations. We
compare our results with other theoretical approaches.
Keywords
One-dimensional electron gasBose gas
contact interaction
correlation effects
local-field correction
STLS approximation
Vashishta-Singwi approximation
structure factors
paircorrelation functions
collective excitations