1,545 research outputs found
Matrix product representation of gauge invariant states in a Z_2 lattice gauge theory
The Gauss law needs to be imposed on quantum states to guarantee gauge
invariance when one studies gauge theory in hamiltonian formalism. In this
work, we propose an efficient variational method based on the matrix product
ansatz for a Z_2 lattice gauge theory on a spatial ladder chain. Gauge
invariant low-lying states are identified by evaluating expectation values of
the Gauss law operator after numerical diagonalization of the gauge
hamiltonian.Comment: 15 pages, 6 figures, minor corrections, accepted for publication in
JHE
Fitting Voronoi Diagrams to Planar Tesselations
Given a tesselation of the plane, defined by a planar straight-line graph
, we want to find a minimal set of points in the plane, such that the
Voronoi diagram associated with "fits" \ . This is the Generalized
Inverse Voronoi Problem (GIVP), defined in \cite{Trin07} and rediscovered
recently in \cite{Baner12}. Here we give an algorithm that solves this problem
with a number of points that is linear in the size of , assuming that the
smallest angle in is constant.Comment: 14 pages, 8 figures, 1 table. Presented at IWOCA 2013 (Int. Workshop
on Combinatorial Algorithms), Rouen, France, July 201
Various Super Yang-Mills Theories with Exact Supersymmetry on the Lattice
We continue to construct lattice super Yang-Mills theories along the line
discussed in the previous papers \cite{sugino, sugino2}. In our construction of
theories in four dimensions, the problem of degenerate vacua
seen in \cite{sugino} is resolved by extending some fields and soaking up
would-be zero-modes in the continuum limit, while in the weak coupling
expansion some surplus modes appear both in bosonic and fermionic sectors
reflecting the exact supersymmetry. A slight modification to the models is made
such that all the surplus modes are eliminated in two- and three-dimensional
models obtained by dimensional reduction thereof. models in
three dimensions need fine-tuning of three and one parameters respectively to
obtain the desired continuum theories, while two-dimensional models with do not require any fine-tuning.Comment: 28 pages, no figure, LaTeX, JHEP style; (v2) published version to
JHEP; (v3) argument on the vacuum degeneracy revised, 34 page
Generalized Theorems for Nonlinear State Space Reconstruction
Takens' theorem (1981) shows how lagged variables of a single time series can be used as proxy variables to reconstruct an attractor for an underlying dynamic process. State space reconstruction (SSR) from single time series has been a powerful approach for the analysis of the complex, non-linear systems that appear ubiquitous in the natural and human world. The main shortcoming of these methods is the phenomenological nature of attractor reconstructions. Moreover, applied studies show that these single time series reconstructions can often be improved ad hoc by including multiple dynamically coupled time series in the reconstructions, to provide a more mechanistic model. Here we provide three analytical proofs that add to the growing literature to generalize Takens' work and that demonstrate how multiple time series can be used in attractor reconstructions. These expanded results (Takens' theorem is a special case) apply to a wide variety of natural systems having parallel time series observations for variables believed to be related to the same dynamic manifold. The potential information leverage provided by multiple embeddings created from different combinations of variables (and their lags) can pave the way for new applied techniques to exploit the time-limited, but parallel observations of natural systems, such as coupled ecological systems, geophysical systems, and financial systems. This paper aims to justify and help open this potential growth area for SSR applications in the natural sciences
Magnitude and Sign Correlations in Heartbeat Fluctuations
We propose an approach for analyzing signals with long-range correlations by
decomposing the signal increment series into magnitude and sign series and
analyzing their scaling properties. We show that signals with identical
long-range correlations can exhibit different time organization for the
magnitude and sign. We find that the magnitude series relates to the nonlinear
properties of the original time series, while the sign series relates to the
linear properties. We apply our approach to the heartbeat interval series and
find that the magnitude series is long-range correlated, while the sign series
is anticorrelated and that both magnitude and sign series may have clinical
applications.Comment: 4 pages,late
Analysis of Iophenoxic Acid Analogues in Small Indian Mongoose (\u3ci\u3eHerpestes Auropunctatus\u3c/i\u3e) Sera for Use as an Oral Rabies Vaccination Biological Marker
The small Indian mongoose (Herpestes auropunctatus) is a reservoir of rabies virus (RABV) in Puerto Rico and comprises over 70% of animal rabies cases reported annually. The control of RABV circulation in wildlife reservoirs is typically accomplished by a strategy of oral rabies vaccination (ORV). Currently no wildlife ORV program exists in Puerto Rico. Research into oral rabies vaccines and various bait types for mongooses has been conducted with promising results. Monitoring the success of ORV relies on estimating bait uptake by target species, which typically involves evaluating a change in RABV neutralizing antibodies (RVNA) post vaccination. This strategy may be difficult to interpret in areas with an active wildlife ORV program or in areas where RABV is enzootic and background levels of RVNA are present in reservoir species. In such situations, a biomarker incorporated with the vaccine or the bait matrix may be useful. We offered 16 captive mongooses placebo ORV baits containing ethyl-iophenoxic acid (et-IPA) in concentrations of 0.4% and 1% inside the bait and 0.14% in the external bait matrix. We also offered 12 captive mongooses ORV baits containing methyl-iophenoxic acid (me-IPA) in concentrations of 0.035%, 0.07% and 0.14% in the external bait matrix. We collected a serum sample prior to bait offering and then weekly for up to eight weeks post offering. We extracted Iophenoxic acids from sera into acetonitrile and quantified using liquid chromatography/mass spectrometry. We analyzed sera for et-IPA or me-IPA by liquid chromatography-mass spectrometry. We found adequate marking ability for at least eight and four weeks for et- and me-IPA, respectively. Both IPA derivatives could be suitable for field evaluation of ORV bait uptake in mongooses. Due to the longevity of the marker in mongoose sera, care must be taken to not confound results by using the same IPA derivative during consecutive evaluations
Quantifying Robotic Swarm Coverage
In the field of swarm robotics, the design and implementation of spatial
density control laws has received much attention, with less emphasis being
placed on performance evaluation. This work fills that gap by introducing an
error metric that provides a quantitative measure of coverage for use with any
control scheme. The proposed error metric is continuously sensitive to changes
in the swarm distribution, unlike commonly used discretization methods. We
analyze the theoretical and computational properties of the error metric and
propose two benchmarks to which error metric values can be compared. The first
uses the realizable extrema of the error metric to compute the relative error
of an observed swarm distribution. We also show that the error metric extrema
can be used to help choose the swarm size and effective radius of each robot
required to achieve a desired level of coverage. The second benchmark compares
the observed distribution of error metric values to the probability density
function of the error metric when robot positions are randomly sampled from the
target distribution. We demonstrate the utility of this benchmark in assessing
the performance of stochastic control algorithms. We prove that the error
metric obeys a central limit theorem, develop a streamlined method for
performing computations, and place the standard statistical tests used here on
a firm theoretical footing. We provide rigorous theoretical development,
computational methodologies, numerical examples, and MATLAB code for both
benchmarks.Comment: To appear in Springer series Lecture Notes in Electrical Engineering
(LNEE). This book contribution is an extension of our ICINCO 2018 conference
paper arXiv:1806.02488. 27 pages, 8 figures, 2 table
Analysis of Iophenoxic Acid Analogues in Small Indian Mongoose (\u3ci\u3eHerpestes Auropunctatus\u3c/i\u3e) Sera for Use as an Oral Rabies Vaccination Biological Marker
The small Indian mongoose (Herpestes auropunctatus) is a reservoir of rabies virus (RABV) in Puerto Rico and comprises over 70% of animal rabies cases reported annually. The control of RABV circulation in wildlife reservoirs is typically accomplished by a strategy of oral rabies vaccination (ORV). Currently no wildlife ORV program exists in Puerto Rico. Research into oral rabies vaccines and various bait types for mongooses has been conducted with promising results. Monitoring the success of ORV relies on estimating bait uptake by target species, which typically involves evaluating a change in RABV neutralizing antibodies (RVNA) post vaccination. This strategy may be difficult to interpret in areas with an active wildlife ORV program or in areas where RABV is enzootic and background levels of RVNA are present in reservoir species. In such situations, a biomarker incorporated with the vaccine or the bait matrix may be useful. We offered 16 captive mongooses placebo ORV baits containing ethyl-iophenoxic acid (et-IPA) in concentrations of 0.4% and 1% inside the bait and 0.14% in the external bait matrix. We also offered 12 captive mongooses ORV baits containing methyl-iophenoxic acid (me-IPA) in concentrations of 0.035%, 0.07% and 0.14% in the external bait matrix. We collected a serum sample prior to bait offering and then weekly for up to eight weeks post offering. We extracted Iophenoxic acids from sera into acetonitrile and quantified using liquid chromatography/mass spectrometry. We analyzed sera for et-IPA or me-IPA by liquid chromatography-mass spectrometry. We found adequate marking ability for at least eight and four weeks for et- and me-IPA, respectively. Both IPA derivatives could be suitable for field evaluation of ORV bait uptake in mongooses. Due to the longevity of the marker in mongoose sera, care must be taken to not confound results by using the same IPA derivative during consecutive evaluations
Phase transition in the collisionless regime for wave-particle interaction
Gibbs statistical mechanics is derived for the Hamiltonian system coupling
self-consistently a wave to N particles. This identifies Landau damping with a
regime where a second order phase transition occurs. For nonequilibrium initial
data with warm particles, a critical initial wave intensity is found: above it,
thermodynamics predicts a finite wave amplitude in the limit of infinite N;
below it, the equilibrium amplitude vanishes. Simulations support these
predictions providing new insight on the long-time nonlinear fate of the wave
due to Landau damping in plasmas.Comment: 12 pages (RevTeX), 2 figures (PostScript
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