8,617 research outputs found
Momentum polarization: an entanglement measure of topological spin and chiral central charge
Topologically ordered states are quantum states of matter with topological
ground state degeneracy and quasi-particles carrying fractional quantum numbers
and fractional statistics. The topological spin is an
important property of a topological quasi-particle, which is the Berry phase
obtained in the adiabatic self-rotation of the quasi-particle by . For
chiral topological states with robust chiral edge states, another fundamental
topological property is the edge state chiral central charge . In this paper
we propose a new approach to compute the topological spin and chiral central
charge in lattice models by defining a new quantity named as the momentum
polarization. Momentum polarization is defined on the cylinder geometry as a
universal subleading term in the average value of a "partial translation
operator". We show that the momentum polarization is a quantum entanglement
property which can be computed from the reduced density matrix, and our
analytic derivation based on edge conformal field theory shows that the
momentum polarization measures the combination of
topological spin and central charge. Numerical results are obtained for two
example systems, the non-Abelian phase of the honeycomb lattice Kitaev model,
and the Laughlin state of a fractional Chern insulator described by a
variational Monte Carlo wavefunction. The numerical results verifies the
analytic formula with high accuracy, and further suggests that this result
remains robust even when the edge states cannot be described by a conformal
field theory. Our result provides a new efficient approach to characterize and
identify topological states of matter from finite size numerics.Comment: 13 pages, 8 figure
Turbulence control by developing a spiral wave with a periodic signal injection in the complex Ginzburg-Landau equation
Turbulence control in the two-dimensional complex Ginzburg-Landau equation is
investigated. A new approach is proposed for the control purpose. In the
presence of a small spiral wave seed initiation, a fully developed turbulence
can be completely annihilated by injecting a single periodic signal to a small
fixed space area around the spiral wave tip. The control is achieved in a
parameter region where the spiral wave of the uncontrolled system is absolutely
unstable. The robustness, convenience and high control efficiency of this
method is emphasized, and the mechanism underlying these practical advantages
are intuitively understood.Comment: 12 pages, figures can be found in the following journa
AGRICULTURAL TECHNOLOGY EXTENSION SYSTEM IN CHINAļ¼ CURRENT SITUATION AND REFORM DIRECTION
This paper presents the evolution of Chinaās Agricultural Technology Extension (ATE) System since its inception in 1920s. Chinaās ATE system has gone through 5 stages before the current system was formed. It evolved from basic-level extension network in 1950s, mid-level extension organizations in 1960sļ¼gradually into nation-wide extension system in 1980s. The participative extension network was reconstructed during āthe Cultural Revolutionā period. The reform of extension system of China has been intensified since 1992 and the five-level Agricultural Technology Extension organizations were basically established. Compared with those previous ones, the current extension system is much better in its setting hierarchy, functions and extension efficiency. However, at present, Chinaās ATE system is also facing such problems as investment deficiency, low-quality and redundant extension team, failure to meet the market needs and government domination, etc. Based on these problems, some reform directions and measures to perfect Chinaās ATE system are proposed. Key words: evolution, Chinaās Agricultural Extension Technology System, history, status quo, refor
Data on Breastfeeding and State Policies in the United States
Breastfeeding is critically important to maternal and child health in the United States. Examining the relationship between breastfeeding outcomes and state policies requires multidisciplinary efforts to link data from various sources. This article describes an integrated dataset that was used to understand the relationship between participation in a nutrition assistance program and low-income children\u27s breastfeeding outcomes [1]. This dataset merged public health information from the National Immunization Surveys Data from 2006 to 2016 and matching state policy data from the Correlates of State Policy Project (CSPP), the U.S. Department of Agriculture/Economic Research Services (USDA/ERS) Supplemental Nutrition Assistance Program (SNAP) Policy Index, the U.S. Bureau of Labor Statistics (BLS), Centers for Medicare & Medicaid Services (CMS), and the Census Bureau. The integrated dataset compiles variables in breastfeeding outcome, child\u27s and mother\u27s socio-demographic characteristics, and state-level policy measures, including SNAP participation rates, SNAP policy indices, unemployment rates, and Children\u27s Health Insurance Program (CHIP) enrollment rates. This multidisciplinary dataset included information on a total of 219,904 children with 98 variables
SPECT Molecular Imaging in Parkinson's Disease
Parkinson's disease (PD) is a common disorder, and the diagnosis of Parkinson's disease is clinical and relies on the presence of characteristic motor symptoms. The accuracy of the clinical diagnosis of PD is still limited. Functional neuroimaging using SPECT technique is helpful in patients with first signs of parkinsonism. The changes detected may reflect the disease process itself and/or compensatory responses to the disease, or they may arise in association with disease- and/or treatment-related complications. This paper addresses the value of SPECT in early differential diagnosis of PD and its potential as a sensitive tool to assess the pathophysiology and progression, as well as the therapeutic efficacy of PD
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