8,979 research outputs found
A Hybrid Long-Distance Entanglement Distribution Protocol
We propose a hybrid (continuous-discrete variable) quantum repeater protocol
for distribution of entanglement over long distances. Starting from entangled
states created by means of single-photon detection, we show how entangled
coherent state superpositions, also known as `Schr\"odinger cat states', can be
generated by means of homodyne detection of light. We show that
near-deterministic entanglement swapping with such states is possible using
only linear optics and homodyne detectors, and we evaluate the performance of
our protocol combining these elements.Comment: 4 pages, 3 figure
Inducing spin-dependent tunneling to probe magnetic correlations in optical lattices
We suggest a simple experimental method for probing antiferromagnetic spin
correlations of two-component Fermi gases in optical lattices. The method
relies on a spin selective Raman transition to excite atoms of one spin species
to their first excited vibrational mode where the tunneling is large. The
resulting difference in the tunneling dynamics of the two spin species can then
be exploited, to reveal the spin correlations by measuring the number of doubly
occupied lattice sites at a later time. We perform quantum Monte Carlo
simulations of the spin system and solve the optical lattice dynamics
numerically to show how the timed probe can be used to identify
antiferromagnetic spin correlations in optical lattices.Comment: 5 pages, 5 figure
Use of the County Health Rankings by Local Health Departments in Florida, 2010 - 2011
This paper describes how local health departments (LHDs) in Florida used the County Health Rankings over the first two years of their release (2010 – 2011). We surveyed LHD leadership to describe if, how and to what extent the Rankings were used by Florida’s 67 LHDs to improve the health of their communities and describe changes in use from the 2010 to the 2011 release. Our results indicate substantial use of the Rankings by Florida’s LHDs, particularly as applied to community health assessments, staff education, as a starting point for examining other indicators and databases, and in grant applications. From 2010 to 2011, we found significant increases in LHD use of the Rankings to build broad multisectoral community involvement in the solution of community health problems. However, media engagement with the Rankings appears to have decreased with time. A primary implication for public health practice is the apparent utility of the Rankings as a tool for community organizing around public health issues and communicating the multifactorial nature of health
SU(2)-invariant spin-1/2 Hamiltonians with RVB and other valence bond phases
We construct a family of rotationally invariant, local, S=1/2 Klein
Hamiltonians on various lattices that exhibit ground state manifolds spanned by
nearest-neighbor valence bond states. We show that with selected perturbations
such models can be driven into phases modeled by well understood quantum dimer
models on the corresponding lattices. Specifically, we show that the
perturbation procedure is arbitrarily well controlled by a new parameter which
is the extent of decoration of the reference lattice. This strategy leads to
Hamiltonians that exhibit i) RVB phases in two dimensions, ii) U(1) RVB
phases with a gapless ``photon'' in three dimensions, and iii) a Cantor
deconfined region in two dimensions. We also construct two models on the
pyrochlore lattice, one model exhibiting a RVB phase and the other a U(1)
RVB phase.Comment: 16 pages, 15 figures; 1 figure and some references added; some minor
typos fixe
The shift to authenticity: a framework for analysis of political truth claims
It is often claimed that political disinformation is more abundant than ever, that populists are particularly prone to lying, and that we live in an era of post-truth or epistemic relativism. Contrary to these views, we interpret this historical trend as a shift from objective to authentic forms of political truth claims. We develop a diagnostic framework that captures different types of political truth claims and their distinct elements. This framework enables interrogation and understanding of the current state of epistemic contestation and change. The rise of both populist and deliberative approaches to democracy, which we use as key examples, are indicators of a gradual shift towards a greater importance of authenticity in the public sphere. We nuance this proposition by distinguishing between different forms of authenticity employed by populist and deliberative politics: communicative authenticity in deliberative politics and original and personal authenticity in populist politics
Entanglement in a two-identical-particle system
The definition of entanglement in identical-particle system is introduced.
The separability criterion in two-identical particle system is given. The
physical meaning of the definition is analysed. Applications to two-boson and
two-fermion systems are made. It is found new entanglement and correlation
phenomena in identical-boson systems exist, and they may have applications in
the field of quantum information.Comment: 4 page
Towards a model for protein production rates
In the process of translation, ribosomes read the genetic code on an mRNA and
assemble the corresponding polypeptide chain. The ribosomes perform discrete
directed motion which is well modeled by a totally asymmetric simple exclusion
process (TASEP) with open boundaries. Using Monte Carlo simulations and a
simple mean-field theory, we discuss the effect of one or two ``bottlenecks''
(i.e., slow codons) on the production rate of the final protein. Confirming and
extending previous work by Chou and Lakatos, we find that the location and
spacing of the slow codons can affect the production rate quite dramatically.
In particular, we observe a novel ``edge'' effect, i.e., an interaction of a
single slow codon with the system boundary. We focus in detail on ribosome
density profiles and provide a simple explanation for the length scale which
controls the range of these interactions.Comment: 8 pages, 8 figure
Evidence from Identified Particles for Active Quark and Gluon Degrees of Freedom
Measurements of intermediate pT (1.5 < pT < 5.0 GeV/c) identified particle
distributions in heavy ion collisions at SPS and RHIC energies display striking
dependencies on the number of constituent quarks in the corresponding hadron.
One finds that elliptic flow at intermediate pT follows a constituent quark
scaling law as predicted by models of hadron formation through coalescence. In
addition, baryon production is also found to increase with event multiplicity
much faster than meson production. The rate of increase is similar for all
baryons, and seemingly independent of mass. This indicates that the number of
constituent quarks determines the multiplicity dependence of identified hadron
production at intermediate pT. We review these measurements and interpret the
experimental findings.Comment: 8 pages, 5 figures, proceedings for SQM2006 conference in Los Angele
Reconstruction on trees and spin glass transition
Consider an information source generating a symbol at the root of a tree
network whose links correspond to noisy communication channels, and
broadcasting it through the network. We study the problem of reconstructing the
transmitted symbol from the information received at the leaves. In the large
system limit, reconstruction is possible when the channel noise is smaller than
a threshold.
We show that this threshold coincides with the dynamical (replica symmetry
breaking) glass transition for an associated statistical physics problem.
Motivated by this correspondence, we derive a variational principle which
implies new rigorous bounds on the reconstruction threshold. Finally, we apply
a standard numerical procedure used in statistical physics, to predict the
reconstruction thresholds in various channels. In particular, we prove a bound
on the reconstruction problem for the antiferromagnetic ``Potts'' channels,
which implies, in the noiseless limit, new results on random proper colorings
of infinite regular trees.
This relation to the reconstruction problem also offers interesting
perspective for putting on a clean mathematical basis the theory of glasses on
random graphs.Comment: 34 pages, 16 eps figure
Suspended and Dissolved Solids Effects on Freshwater Biota: A Review
It is widely recognized that suspended and dissolved solids in lakes, rivers, streams, and reservoirs affect water quality. In this report the research needs appropriate to setting freshwater quality criteria or standards for suspeneded solids (not including bedload) and dissolveed solids are defined by determining the state of our knowledge from a critical review of the recent literature in this field. Common literature sources and computer searching routines were used as an initial source of information followed by detailed journal searches. Although some 185 journal articles, government reports, and other referecnes were cited herein (about 45 percent publicshed since 1974) and many other reports (about 300 citation) were reviewed, there is a dearth of quantitative information on the response of freshwater biota, especially at the community level, to suspended and dissolved solids. Consequently, the major research need was defined as the development and-or application of concepts of community response to suspended and dissolved solids concentrations and loads. These concepts need to be applied especially to the photosynthetic lebel and the microfauna and macrofauna levels. Fish studies are of lower priority since more and better research has been reported for these organisms. In addition, the role of suspended solids in transporting toix substances (organics, heavy metals), aesthetic evaluation of suspened solids in aquatic ecosystems and dissolved solids in drinking water, and economic aspects of dissolved solids in municipal-industrial water were defined as research needs
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