287 research outputs found
Self-Consistent Theory of Anderson Localization: General Formalism and Applications
The self-consistent theory of Anderson localization of quantum particles or
classical waves in disordered media is reviewed. After presenting the basic
concepts of the theory of Anderson localization in the case of electrons in
disordered solids, the regimes of weak and strong localization are discussed.
Then the scaling theory of the Anderson localization transition is reviewed.
The renormalization group theory is introduced and results and consequences are
presented. It is shown how scale-dependent terms in the renormalized
perturbation theory of the inverse diffusion coefficient lead in a natural way
to a self-consistent equation for the diffusion coefficient. The latter
accounts quantitatively for the static and dynamic transport properties except
for a region near the critical point. Several recent applications and
extensions of the self-consistent theory, in particular for classical waves,
are discussed.Comment: 25 pages, 2 figures; published version including correction
Transport through asymmetric two-lead junctions of Luttinger liquid wires
We calculate the conductance of a system of two spinless Luttinger liquid
wires with different interaction strengths g_1, g_2, connected through a short
junction, within the scattering state formalism. Following earlier work we
formulate the problem in current algebra language, and calculate the scale
dependent contribution to the conductance in perturbation theory keeping the
leading universal contributions to all orders in the interaction strength. From
that we derive a renormalization group (RG) equation for the conductance. The
analytical solution of the RG-equation is discussed in dependence on g_1, g_2.
The regions of stability of the two fixed points corresponding to conductance
G=0 and G=1, respectively, are determined.Comment: 6 pages, 3 figures, REVTE
Transport of interacting electrons through a potential barrier: nonperturbative RG approach
We calculate the linear response conductance of electrons in a Luttinger
liquid with arbitrary interaction g_2, and subject to a potential barrier of
arbitrary strength, as a function of temperature. We first map the Hamiltonian
in the basis of scattering states into an effective low energy Hamiltonian in
current algebra form. Analyzing the perturbation theory in the fermionic
representation the diagrams contributing to the renormalization group (RG)
\beta-function are identified. A universal part of the \beta-function is given
by a ladder series and summed to all orders in g_2. First non-universal
corrections beyond the ladder series are discussed. The RG-equation for the
temperature dependent conductance is solved analytically. Our result agrees
with known limiting cases.Comment: 6 pages, 5 figure
DMRG evaluation of the Kubo formula -- Conductance of strongly interacting quantum systems
In this paper we present a novel approach combining linear response theory
(Kubo) for the conductance and the Density Matrix Renormalization Group (DMRG).
The system considered is one-dimensional and consists of non-interacting tight
binding leads coupled to an interacting nanostructure via weak links. Electrons
are treated as spinless fermions and two different correlation functions are
used to evaluate the conductance.
Exact diagonalization calculations in the non-interacting limit serve as a
benchmark for our combined Kubo and DMRG approach in this limit. Including both
weak and strong interaction we present DMRG results for an extended
nanostructure consisting of seven sites. For the strongly interacting structure
a simple explanation of the position of the resonances is given in terms of
hard-core particles moving freely on a lattice of reduced size.Comment: 7 pages, 2 figures. Minor typos correcte
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