18 research outputs found
Explicit mapping between a 2D quantum Hall system and a 1D Luttinger liquid, I. Luttinger parameters
We study a simple model of a quantum Hall system with the electrons confined
to a linear, narrow channel. The system is mapped to a 1D system which in the
low-energy approximation has the form of a Luttinger liquid with different
interactions between particles of equal and of opposite chiralities. We study
this mapping at the microscopic level, and discuss the relation between the
parameters of the 2D system and the corresponding 1D Luttinger liquid
parameters. We focus in particular on how the parameters are renormalized by
the electron interactions and show that the velocity parameter of the current
is not modified by the interaction.Comment: Latex, 22 pages, 1 figur
Enhancing triplet superconductivity by the proximity to a singlet superconductor in oxide heterostructures
We show how in principle a coherent coupling between two superconductors of
opposite parity can be realized in a three-layer oxide heterostructure. Due to
strong intraionic spin-orbit coupling in the middle layer, singlet Cooper pairs
are converted into triplet ones and vice versa. This results in a large
enhancement of the triplet superconductivity, persisting well above the native
triplet critical temperature.Comment: Minor improvements, references added, published version. 5 pages, 3
figure
Charge Fractionalization on Quantum Hall Edges
We discuss the propagation and fractionalization of localized charges on the
edges of quantum Hall bars of variable widths, where interactions between the
edges give rise to Luttinger liquid behavior with a non-trivial interaction
parameter g. We focus in particular on the separation of an initial charge
pulse into a sharply defined front charge and a broader tail. The front pulse
describes an adiabatically dressed electron which carries a non-integer charge,
which is \sqrt{g} times the electron charge. We discuss how the presence of
this fractional charge can, in principle, be detected through measurements of
the noise in the current created by tunneling of electrons into the system. The
results are illustrated by numerical simulations of a simplified model of the
Hall bar.Comment: 15 page
Are there sharp fractional charges in Luttinger liquids?
We examine charge fractionalization by chiral separation in a one-dimensional
fermion system described by Luttinger liquid theory. The focus is on the
question of whether the fractional charges are quantum mechanically sharp, and
in the analysis we make a distinction between the global charge, which is
restricted by boundary conditions, and the local charge where a background
contribution is subtracted. We show, by way of examples, that fractional
charges of arbitrary values, all which are quantum mechanically sharp, can be
introduced by different initial conditions. Since the system is gapless,
excitations of arbitrary low frequency contribute to the fluctuations, it is
important to make a precise definition of sharp charges, and this we we do by
subtraction of the ground state contribution. We very briefly comment on the
relevance of our analysis for proposed experiments.Comment: One reference update