11,401 research outputs found
Inequalities for electron-field correlation functions
I show that there exists a class of inequalities between correlation
functions of different orders of a chaotic electron field. These inequalities
lead to the antibunching effect and are a consequence of the fact that
electrons are fermions -- indistinguishable particles with antisymmetric
states. The derivation of the inequalities is based on the known form of the
correlation functions for the chaotic state and on the properties of matrices
and determinants.Comment: 8 pages Latex2e, 2 eps figure
Word Adjacency Graph Modeling: Separating Signal From Noise in Big Data
There is a need to develop methods to analyze Big Data to inform patient-centered interventions for better health outcomes. The purpose of this study was to develop and test a method to explore Big Data to describe salient health concerns of people with epilepsy. Specifically, we used Word Adjacency Graph modeling to explore a data set containing 1.9 billion anonymous text queries submitted to the ChaCha question and answer service to (a) detect clusters of epilepsy-related topics, and (b) visualize the range of epilepsy-related topics and their mutual proximity to uncover the breadth and depth of particular topics and groups of users. Applied to a large, complex data set, this method successfully identified clusters of epilepsy-related topics while allowing for separation of potentially non-relevant topics. The method can be used to identify patient-driven research questions from large social media data sets and results can inform the development of patient-centered interventions
Topological phase for entangled two-qubit states and the representation of the SO(3)group
We discuss the representation of the group by two-qubit maximally
entangled states (MES). We analyze the correspondence between and the
set of two-qubit MES which are experimentally realizable. As a result, we offer
a new interpretation of some recently proposed experiments based on MES.
Employing the tools of quantum optics we treat in terms of two-qubit MES some
classical experiments in neutron interferometry, which showed the -phase
accrued by a spin- particle precessing in a magnetic field. By so doing,
we can analyze the extent to which the recently proposed experiments - and
future ones of the same sort - would involve essentially new physical aspects
as compared with those performed in the past. We argue that the proposed
experiments do extend the possibilities for displaying the double connectedness
of , although for that to be the case it results necessary to map
elements of onto physical operations acting on two-level systems.Comment: 25 pages, 9 figure
Chiral molecules split light: Reflection and refraction in a chiral liquid
A light beam changes direction as it enters a liquid at an angle from another
medium, such as air. Should the liquid contain molecules that lack mirror
symmetry, then it has been predicted by Fresnel that the light beam will not
only change direction, but will actually split into two separate beams with a
small difference in the respective angles of refraction. Here we report the
observation of this phenomenon. We also demonstrate that the angle of
reflection does not equal the angle of incidence in a chiral medium. Unlike
conventional optical rotation, which depends on the path-length through the
sample, the reported reflection and refraction phenomena arise within a few
wavelengths at the interface and thereby suggest a new approach to polarimetry
that can be used in microfluidic volumes
Image Coaddition with Temporally Varying Kernels
Large, multi-frequency imaging surveys, such as the Large Synaptic Survey
Telescope (LSST), need to do near-real time analysis of very large datasets.
This raises a host of statistical and computational problems where standard
methods do not work. In this paper, we study a proposed method for combining
stacks of images into a single summary image, sometimes referred to as a
template. This task is commonly referred to as image coaddition. In part, we
focus on a method proposed in previous work, which outlines a procedure for
combining stacks of images in an online fashion in the Fourier domain. We
evaluate this method by comparing it to two straightforward methods through the
use of various criteria and simulations. Note that the goal is not to propose
these comparison methods for use in their own right, but to ensure that
additional complexity also provides substantially improved performance
The Full Range of Predictions for B Physics From Iso-singlet Down Quark Mixing
We extend the range of predictions of the isosinglet (or vector) down quark
model to the fully allowed physical ranges, and also update this with the
effect of new physics constraints. We constrain the present allowed ranges of
sin(2*beta) and sin(2*alpha), gamma, x_s, and A_{B_s}. In models allowing
mixing to a new isosinglet down quark (as in E_6) flavor changing neutral
currents are induced that allow a Z^0 mediated contribution to B-Bbar mixing
and which bring in new phases. In (rho, eta), (x_s, sin(gamma)), and (x_s,
A_{B_s}) plots for the extra isosinglet down quark model which are herein
extended to the full physical range, we find new allowed regions that will
require experiments on sin(gamma) and/or x_s to verify or to rule out an extra
down quark contribution.Comment: 13 pages in RevTeX, 7 postscript figure
Iso-singlet Down Quark Mixing And CP Violation Experiments
We confront the new physics models with extra iso-singlet down quarks in the
new CP violation experimental era with and
measurements, events, and
limits. The closeness of the new experimental results to the standard
model theory requires us to include full SM amplitudes in the analysis. In
models allowing mixing to a new isosinglet down quark, as in E, flavor
changing neutral currents are induced that allow a mediated contribution
to mixing and which bring in new phases. In ,
, and plots we still find much
larger regions in the four down quark model than in the SM, reaching down to
, , , and down to zero, all at 1. We elucidate
the nature of the cancellation in an order four down quark mixing
matrix element which satisfies the experiments and reduces the number of
independent angles and phases. We also evaluate tests of unitarity for the
CKM submatrix.Comment: 14 pages, 16 figures, REVTeX
Family support and cardiac rehabilitation: A comparative study of the experiences of South Asian and White-European patients and their carer's living in the United Kingdom
Background: Effective lifestyle modification facilitated by cardiac rehabilitation is known to reduce the occurrence of adverse coronary events and mortality. South Asians have poorer outcomes after a myocardial infarction than the general UK population, but little is known about their experiences of family support, cardiac rehabilitation and lifestyle change. Aims: To explore the nature of family support available to a sample of South Asian and White-European cardiac patients and to highlight similarities and differences between these groups with regard to cardiac rehabilitation and lifestyle modification. Methods: Using a qualitative approach, semi-structured interviews (in 1 of 6 languages) were conducted by researchers with; 45 South Asian patients and 37 carers and 20 White-European patients and 17 carers. Interviews were conducted in a home setting, up to eighteen months after discharge from hospital following myocardial infarction, coronary artery bypass surgery or unstable angina. Results: The main themes that emerged related to the provision of advice and information, family support and burden, dietary change and exercise regimes. Conclusions: Several cultural and ethnic differences were identified between patients and their families alongside similarities, irrespective of ethnicity. These may represent generic characteristics of recovery after a cardiac event. Health professionals should develop a cultural repertoire to engage with diversity and difference. Not every difficulty a person encounters as they try to access appropriate service delivery can be attributed to ethnic background. By improving services generally, support for South Asian populations can be improved. The challenge is to know when ethnicity makes a difference and mediates a person's relationship with service support and when it does not. (C) 2007 European Society of Cardiology. Published by Elsevier B.V. All rights reserved
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