1,121 research outputs found
Characterization of topological states on a lattice with Chern number
We study Chern numbers to characterize the ground state of strongly
interacting systems on a lattice. This method allows us to perform a numerical
characterization of bosonic fractional quantum Hall (FQH) states on a lattice
where conventional overlap calculation with known continuum case such as
Laughlin state, breaks down due to the lattice structure or dipole-dipole
interaction. The non-vanishing Chern number indicates the existence of a
topological order in the degenerate ground state manifold.Comment: 5 pages, 3 figures, V2: changes in the presentatio
Topologically Robust Transport of Photons in a Synthetic Gauge Field
Electronic transport in low dimensions through a disordered medium leads to
localization. The addition of gauge fields to disordered media leads to
fundamental changes in the transport properties. For example, chiral edge
states can emerge in two-dimensional systems with a perpendicular magnetic
field. Here, we implement a "synthetic'' gauge field for photons using
silicon-on-insulator technology. By determining the distribution of transport
properties, we confirm the localized transport in the bulk and the suppression
of localization in edge states, using the "gold standard'' for localization
studies. Our system provides a new platform to investigate transport properties
in the presence of synthetic gauge fields, which is important both from the
fundamental perspective of studying photonic transport and for applications in
classical and quantum information processing.Comment: 4.5 pages, 3 figures and supplementary materia
Photonic quantum transport in a nonlinear optical fiber
We theoretically study the transmission of few-photon quantum fields through a strongly nonlinear optical medium. We develop a general approach to investigate nonequilibrium quantum transport of bosonic fields through a finite-size nonlinear medium and apply it to a recently demonstrated experimental system where cold atoms are loaded in a hollow-core optical fiber. We show that when the interaction between photons is effectively repulsive, the system acts as a single-photon switch. In the case of attractive interaction, the system can exhibit either antibunching or bunching, associated with the resonant excitation of bound states of photons by the input field. These effects can be observed by probing statistics of photons transmitted through the nonlinear fiber
Impact of creatinine clearance on helicobacter pylori eradication rate in patients with peptic ulcer disease
Introduction. Gastrointestinal complaints are common in patients with kidney failure. The aim of this study was to investigate the effect of creatinine clearance on Helicobacter pylori (HP) eradication rate in patients with peptic ulcer disease. Materials and Methods. In this clinical trial, 132 patients with a range of kidney function (normal to end-stage renal disease) and peptic ulcer disease with HP infection were enrolled and divided into 5 groups by their creatinine clearance. For all patients, a 14-day standard regimen of triple therapy for peptic ulcer was started with omeprazole, 20 mg; clarithromycin, 500 mg; and amoxicillin, 1 g; twice per day. After 6 weeks, HP eradication rate were evaluated and compared between the groups with urea breath test. Results. The mean age of the participants was 44.84 ± 12.20 years and 68 (51.5%) were women. The five groups were not significantly different in terms of age, sex distribution, or body mass index. The results of urea breath test at 6 weeks were positive in 23 patients (17.4%). There was no significant difference in HP eradication rate (negative urea breath test) between the five groups. Conclusions. This study showed no association between the success rate of eradication of HP infection and kidney function. © 2015, Iranian Society of Nephrology. All rights reserved
High-Order Multipole Radiation from Quantum Hall States in Dirac Materials
We investigate the optical response of strongly disordered quantum Hall
states in two-dimensional Dirac materials and find qualitatively different
effects in the radiation properties of the bulk versus the edge. We show that
the far-field radiation from the edge is characterized by large multipole
moments (> 50) due to the efficient transfer of angular momentum from the
electrons into the scattered light. The maximum multipole transition moment is
a direct measure of the coherence length of the edge states. Accessing these
multipole transitions would provide new tools for optical spectroscopy and
control of quantum Hall edge states. On the other hand, the far-field radiation
from the bulk appears as random dipole emission with spectral properties that
vary with the local disorder potential. We determine the conditions under which
this bulk radiation can be used to image the disorder landscape. Such optical
measurements can probe sub-micron length scales over large areas and provide
complementary information to scanning probe techniques. Spatially resolving
this bulk radiation would serve as a novel probe of the percolation transition
near half-filling.Comment: v2: 8 pages, 4 figure
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