22,862 research outputs found
Geometrical Expression for the Angular Resolution of a Network of Gravitational-Wave Detectors
We report for the first time general geometrical expressions for the angular
resolution of an arbitrary network of interferometric gravitational-wave (GW)
detectors when the arrival-time of a GW is unknown. We show explicitly elements
that decide the angular resolution of a GW detector network. In particular, we
show the dependence of the angular resolution on areas formed by projections of
pairs of detectors and how they are weighted by sensitivities of individual
detectors. Numerical simulations are used to demonstrate the capabilities of
the current GW detector network. We confirm that the angular resolution is poor
along the plane formed by current LIGO-Virgo detectors. A factor of a few to
more than ten fold improvement of the angular resolution can be achieved if the
proposed new GW detectors LCGT or AIGO are added to the network. We also
discuss the implications of our results for the design of a GW detector
network, optimal localization methods for a given network, and electromagnetic
follow-up observations.Comment: 13 pages, for Phys. Rev.
Degeneracy of Multi-Component Quantum Hall States Satisfying Periodic Boundary Conditions
In systems subject to periodic boundary conditions, Haldane has shown that
states at arbitrary filling fraction possess a degeneracy with respect to
center of mass translations. An analysis is carried out for multi-component
electron systems and extra degeneracies are shown to exist. Their application
to numerical studies is discussed.Comment: 16 pages, REVTEX v3.0, revised manuscrip
Hall Drag in Correlated Double Layer Quantum Hall Systems
We show that in the limit of zero temperature, double layer quantum Hall
systems exhibit a novel phenomena called Hall drag, namely a current driven in
one layer induces a voltage drop in the other layer, in the direction
perpendicular to the driving current. The two-by-two Hall resistivity tensor is
quantized and proportional to the matrix that describes the
topological order of the quantum Hall state, even when the matrix
contains a zero eigenvalue, in which case the Hall conductivity tensor does not
exist. Relation between the present work and previous ones is also discussed.Comment: 4 pages, 1 eps figure. Accepted in PRB, R
Time correlations in 1D quantum impurity problems
We develop in this letter an analytical approach using form- factors to
compute time dependent correlations in integrable quantum impurity problems. As
an example, we obtain for the first time the frequency dependent conductivity
for the tunneling between the edges in the fractional
quantum Hall effect, and the spectrum of the spin-spin correlation in
the anisotropic Kondo model and equivalently in the double well system of
dissipative quantum mechanics, both at vanishing temperature.Comment: 4 pages, Revtex and 2 figure
QHE of Bilayer Systems in the Presence of Tunneling -- case --
Transport properties of bilayer quantum Hall systems at , where
is an odd integer, are investigated. The edge theory is used for the
investigation, since tunneling between the two layers is assumed to occur on
the edge of the sample because of the bulk incompressibility. It is shown that
in the case of the independent Laughlin state tunneling is irrelevant when
in the low temperature and long wave length limit. The temperature
dependence of two-terminal conductance of the system in which only one of the
two layers is contacted with electrode is discussed.Comment: 5 page
Structure formation in binary colloids
A theoretical study of the structure formation observed very recently [Phys.
Rev. Lett. 90, 128303 (2003)] in binary colloids is presented. In our model
solely the dipole-dipole interaction of the particles is considered,
electrohidrodynamic effects are excluded. Based on molecular dynamics
simulations and analytic calculations we show that the total concentration of
the particles, the relative concentration and the relative dipole moment of the
components determine the structure of the colloid. At low concentrations the
kinetic aggregation of particles results in fractal structures which show a
crossover behavior when increasing the concentration. At high concentration
various lattice structures are obtained in a good agreement with experiments.Comment: revtex, 4 pages, figures available from authors due to size problem
Thermal states of the Kitaev honeycomb model: a Bures metric analysis
We analyze the Bures metric over the canonical thermal states for the Kitaev
honeycomb mode. In this way the effects of finite temperature on topological
phase transitions can be studied. Different regions in the parameter space of
the model can be clearly identified in terms of different temperature scaling
behavior of the Bures metric tensor. Furthermore, we show a simple relation
between the metric elements and the crossover temperature between the
quasi-critical and the quasi-classical regions. These results extend the ones
of [29,30] to finite temperatures.Comment: 6 pages, 2 figure
Electron operator at the edge of the 1/3 fractional quantum Hall liquid
This study builds upon the work of Palacios and MacDonald (Phys. Rev. Lett.
{\bf 76}, 118 (1996)), wherein they identify the bosonic excitations of Wen's
approach for the edge of the 1/3 fractional quantum Hall state with certain
operators introduced by Stone. Using a quantum Monte Carlo method, we extend to
larger systems containing up to 40 electrons and obtain more accurate
thermodynamic limits for various matrix elements for a short range interaction.
The results are in agreement with those of Palacios and MacDonald for small
systems, but offer further insight into the detailed approach to the
thermodynamic limit. For the short range interaction, the results are
consistent with the chiral Luttinger liquid predictions.We also study
excitations using the Coulomb ground state for up to nine electrons to
ascertain the effect of interactions on the results; in this case our tests of
the chiral Luttinger liquid approach are inconclusive.Comment: 10 pages, 2 figure
Edge states in Open Antiferromagnetic Heisenberg Chains
In this letter we report our results in investigating edge effects of open
antiferromagnetic Heisenberg spin chains with spin magnitudes
using the density-matrix renormalization group (DMRG) method initiated by
White. For integer spin chains, we find that edge states with spin magnitude
exist, in agreement with Valence-Bond-Solid model picture. For
half-integer spin chains, we find that no edge states exist for spin
chain, but edge state exists in spin chain with , in
agreement with previous conjecture by Ng. Strong finite size effects associated
with spin dimmerization in half-integer spin chains will also be discussed.Comment: 4 pages, RevTeX 3.0, 5 figures in a separate uuencoded postscript
file. Replaced once to enlarge the acknowlegement
- …