This book provides an attempt to convey the colorful facets of condensed
matter systems with reduced dimensionality. Some of the specific
features predicted for interacting one-dimensional electron systems,
such as charge- and spin-density waves, have been observed in many
quasi-one-dimensional materials. The two-dimensional world is even
richer: besides d-wave superconductivity and the Quantum Hall Effect -
perhaps the most spectacular phases explored during the last two
decades - many collective charge and spin states have captured the
interest of researchers, such as charge stripes or spontaneously
generated circulating currents.
Recent years have witnessed important progress in material preparation,
measurement techniques and theoretical methods. Today larger and better
samples, higher flux for neutron beams, advanced light sources, better
resolution in electron spectroscopy, new computational algorithms, and
the development of field-theoretical approaches allow an in-depth
analysis of the complex many-body behaviour of low-dimensional
materials. The epoch when simple mean-field arguments were sufficient
for describing the gross features observed experimentally is definitely
over.
The Editors' aim is to thoroughly explain a number of selected topics:
the application of dynamical probes, such as neutron scattering, optical
absorption and photoemission, as well as transport studies, both
electrical and thermal. Some of the more theoretical chapters are
directly relevant for experiments, such as optical spectroscopy,
transport in one-dimensional models, and the phenomenology of charge
inhomogeneities in layered materials, while others discuss more general
topics and methods, for example the concept of a Luttinger liquid and
bosonization, or duality transformations, both promising tools for
treating strongly interacting many-body systems.
