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2009.01651 | In this paper, we study relative deformations of maps into a family of
K\"ahler manifolds whose images are divisors. We show that if the map satisfies
a condition called semiregularity, then it allows relative deformations if and
only if the cycle class of the image remains Hodge in the family. This gives a
refinement of the so-called variational Hodge conjecture. We also show that the
semiregularity of maps is related to classical notions such as Cayley-Bacharach
conditions and d-semistability.
| [
"math.AG"
] | math.AG | Algebraic Geometry | 47Algebraic Geometry
|
|
nucl-th/0606042 | We use a correlated local Fermi gas (LFG) model, which accounts also for long
distance corrections of the RPA type and final-state interactions, to compute
the polarization of the final lepton in charged-current quasielastic neutrino
scattering. The present model has been successfully used in recent studies of
inclusive neutrino nucleus processes and muon capture. We investigate the
relevance of nuclear effects in the particular case of $\tau$ polarization in
tau-neutrino induced reactions for several kinematics of relevance for neutrino
oscillation experiments.
| [
"nucl-th",
"hep-ph"
] | nucl-th | hep-ph | Nuclear Theory;High Energy Physics - Phenomenology | 4,914Nuclear Theory;High Energy Physics - Phenomenology
|
1401.7911 | We consider a class of non-polynomial spline spaces over T-meshes, that is,
of spaces locally spanned both by polynomial and by suitably-chosen
non-polynomial functions, which we will refer to as generalized splines over
T-meshes. For such spaces, we provide, under certain conditions, a dimension
formula and a basis based on the notion of minimal determining set. We
explicitly examine some relevant cases, which enjoy a noteworthy behaviour with
respect to differentiation and integration; finally, we also study the
approximation power of the just constructed spline spaces.
| [
"math.NA"
] | math.NA | Numerical Analysis | 5,002Numerical Analysis
|
|
2203.11611 | In the recent past, greater accessibility to powerful computational resources
has enabled progress in the field of Deep Learning and Computer Vision to grow
by leaps and bounds. This in consequence has lent progress to the domain of
Autonomous Driving and Navigation Systems. Most of the present research work
has been focused on driving scenarios in the European or American roads. Our
paper draws special attention to the Indian driving context. To this effect, we
propose a novel architecture, DR-Gaze, which is used to map the driver's gaze
onto the road. We compare our results with previous works and state-of-the-art
results on the DGAZE dataset. Our code will be made publicly available upon
acceptance of our paper.
| [
"cs.CV"
] | cs.CV | Computer Vision and Pattern Recognition | 1,498Computer Vision and Pattern Recognition
|
|
1101.5465 | We propose the Kolmogorov stochasticity parameter, $\lambda$ for energy level
spectra to classify quantum systems with corresponding classical dynamics
ranging from integrable to chaotic. We also study the probability distribution
function (PDF) of $\lambda$. Remarkably, the PDF of all the integrable systems
studied here is the same and is found to be completely different from the PDF
of chaotic systems. We also note that $\lambda_n$ for $n$ energy levels scales
as $\lambda_n \sim n^{-\alpha}$. Furthermore, with $\alpha$, the stochastic
probability (calculated from PDF) is seen to jump by about an order of
magnitude as the systems turn chaotic.
| [
"nlin.CD"
] | nlin.CD | Chaotic Dynamics | 810Chaotic Dynamics
|
|
2111.12985 | We introduce the notion of Chern-Simons classes for curved DG-pairs and we
prove that a particular case of this general construction provides canonical
$L_\infty$ liftings of Buchweitz-Flenner semiregularity maps for coherent
sheaves on complex manifolds.
| [
"math.AG",
"math.DG",
"math.QA"
] | math.AG | math.DG | Algebraic Geometry;Differential Geometry;Quantum Algebra | 104Algebraic Geometry;Differential Geometry;Quantum Algebra
|
1007.3610 | We study the RHIC data on long range rapidity correlations, comparing their
main trends with different string model simulations. Particular attention is
paid to color percolation model and its similarities with color glass
condensate. As both approaches corresponds, at high density, to a similar
physical picture, both of them give rise to a similar behavior on the energy
and the centrality of the main observables. Color percolation explains the
transition from low density to high density.
| [
"hep-ph"
] | hep-ph | High Energy Physics - Phenomenology | 3,129High Energy Physics - Phenomenology
|
|
2211.12186 | The surface of lines in a cubic fourfold intersecting a fixed line splits
motivically into two parts, one of which resembles a K3 surface. We define the
analogue of the Beauville-Voisin class and study the push-forward map to the
Fano variety of all lines with respect to the natural splitting of the
Bloch-Beilinson filtration introduced by Mingmin Shen and Charles Vial.
| [
"math.AG"
] | math.AG | Algebraic Geometry | 47Algebraic Geometry
|
|
1511.06919 | Segmentation of histopathology sections is an ubiquitous requirement in
digital pathology and due to the large variability of biological tissue,
machine learning techniques have shown superior performance over standard image
processing methods. As part of the GlaS@MICCAI2015 colon gland segmentation
challenge, we present a learning-based algorithm to segment glands in tissue of
benign and malignant colorectal cancer. Images are preprocessed according to
the Hematoxylin-Eosin staining protocol and two deep convolutional neural
networks (CNN) are trained as pixel classifiers. The CNN predictions are then
regularized using a figure-ground segmentation based on weighted total
variation to produce the final segmentation result. On two test sets, our
approach achieves a tissue classification accuracy of 98% and 94%, making use
of the inherent capability of our system to distinguish between benign and
malignant tissue.
| [
"cs.CV"
] | cs.CV | Computer Vision and Pattern Recognition | 1,498Computer Vision and Pattern Recognition
|
|
1402.4800 | The observational signatures of multi-field inflation will generally evolve
as the Universe reheats. We introduce a general analytic formalism for tracking
this evolution through perturbative reheating, applicable to two field models
with arbitrary separable potentials. The various transitions, including the
onset of scalar field oscillations and the reheating of each field, can happen
in different orders and on arbitrary hypersurfaces. The effective equations of
state of the oscillating fields are also arbitrary. Nevertheless, our results
are surprisingly simple. Our formalism encapsulates and generalises a huge
range of previous calculations including two-field inflation, spectator models,
the inhomogeneous end of inflation scenario and numerous generalised curvaton
scenarios.
| [
"astro-ph.CO",
"hep-th"
] | astro-ph.CO | hep-th | Cosmology and Nongalactic Astrophysics;High Energy Physics - Theory | 1,765Cosmology and Nongalactic Astrophysics;High Energy Physics - Theory
|
2007.02037 | Modern statistical analyses often encounter datasets with massive sizes and
heavy-tailed distributions. For datasets with massive sizes, traditional
estimation methods can hardly be used to estimate the extreme value index
directly. To address the issue, we propose here a subsampling-based method.
Specifically, multiple subsamples are drawn from the whole dataset by using the
technique of simple random subsampling with replacement. Based on each
subsample, an approximate maximum likelihood estimator can be computed. The
resulting estimators are then averaged to form a more accurate one. Under
appropriate regularity conditions, we show theoretically that the proposed
estimator is consistent and asymptotically normal. With the help of the
estimated extreme value index, we can estimate high-level quantiles and tail
probabilities of a heavy-tailed random variable consistently. Extensive
simulation experiments are provided to demonstrate the promising performance of
our method. A real data analysis is also presented for illustration purpose.
| [
"stat.ME"
] | stat.ME | Methodology | 4,557Methodology
|
|
0802.4236 | Using the notions of frame transform and of square integrable projective
representation of a locally compact group $G$, we introduce a class of
isometries (tight frame transforms) from the space of Hilbert-Schmidt operators
in the carrier Hilbert space of the representation into the space of square
integrable functions on the direct product group $G\times G$. These transforms
have remarkable properties. In particular, their ranges are reproducing kernel
Hilbert spaces endowed with a suitable 'star product' which mimics, at the
level of functions, the original product of operators. A 'phase space
formulation' of quantum mechanics relying on the frame transforms introduced in
the present paper, and the link of these maps with both the Wigner transform
and the wavelet transform are discussed.
| [
"quant-ph"
] | quant-ph | Quantum Physics | 5,985Quantum Physics
|
|
0909.4356 | Extragalactic surveys in the emission line of [O III] 5007 have provided us
with the absolute line strengths of large, homogeneous sets of planetary
nebulae. These data have been used to address a host of problems, from the
measurement of the extragalactic distance scale, to the study of stellar
populations. I review our current understanding of the [O III] planetary nebula
luminosity function (PNLF), and discuss some of the physical processes that
effect its structure. I also describe the features of the H-alpha PNLF, a
function that, upon first glance, looks similar to the [O III] PNLF, but which
includes a very different set of objects. Finally, I discuss recent
measurements of alpha, the number of PNe found in a stellar population,
normalized to that population's bolometric luminosity. I show that, contrary to
expectations, the values of alpha found in actively star-forming spirals is
essentially the same as those measured in late-type elliptical and lenticular
systems. I discuss how this result sheds light on the physics of the planetary
nebula phenomenon.
| [
"astro-ph.CO",
"astro-ph.GA"
] | astro-ph.CO | astro-ph.GA | Cosmology and Nongalactic Astrophysics;Astrophysics of Galaxies | 1,727Cosmology and Nongalactic Astrophysics;Astrophysics of Galaxies
|
2206.07889 | This paper presents a methodology to construct a divergence-free polynomial
basis of an arbitrary degree in a simplex (triangles in 2D and tetrahedra in
3D) of arbitrary dimension. It allows for fast computation of all numerical
solutions from degree zero to a specified degree \textit{k} for certain PDEs.
The generated divergence-free basis is orthonormal, hierarchical, and robust in
finite-precision arithmetic. At the core is an Arnoldi-based procedure. It
constructs an orthonormal and hierarchical basis for multi-dimensional
polynomials of degree less than or equal to \textit{k}. The divergence-free
basis is generated by combining these polynomial basis functions. An efficient
implementation of the hybridized BDM mixed method is developed using these
basis functions. Hierarchy allows for incremental construction of the global
matrix and the global vector for all degrees (zero to \textit{k}) using the
local problem solution computed just for degree \textit{k}. Orthonormality and
divergence-free properties simplify the local problem. PDEs considered are
Helmholtz, Laplace, and Poisson problems in smooth domains and in a corner
domain. These advantages extend to other PDEs such as incompressible Stokes,
incompressible Navier-Stokes, and Maxwell equations.
| [
"math.NA",
"cs.NA"
] | math.NA | cs.NA | Numerical Analysis;Numerical Analysis | 5,059Numerical Analysis;Numerical Analysis
|
1604.00583 | The structural flexibility of the exponential propagation iterative methods
of Runge-Kutta type (EPIRK) enables construction of particularly efficient
exponential time integrators. While the EPIRK methods have been shown to
perform well on stiff problems, all of the schemes proposed up to now have been
derived using classical order conditions. In this paper we extend the stiff
order conditions and the convergence theory developed for the exponential
Rosenbrock methods to the EPIRK integrators. We derive stiff order conditions
for the EPIRK methods and develop algorithms to solve them to obtain specific
schemes. Moreover, we propose a new approach to constructing particularly
efficient EPIRK integrators that are optimized to work with an adaptive Krylov
algorithm. We use a set of numerical examples to illustrate the computational
advantages that the newly constructed EPIRK methods offer compared to
previously proposed exponential integrators.
| [
"math.NA"
] | math.NA | Numerical Analysis | 5,002Numerical Analysis
|
|
2106.13917 | In this paper, we discuss how certain radio access network optimization
problems can be modelled using the concept of constraint satisfaction problems
in artificial intelligence, and solved at scale using a quantum computer. As a
case study, we discuss root sequence index (RSI) assignment problem - an
important LTE/NR physical random access channel configuration related
automation use-case. We formulate RSI assignment as quadratic unconstrained
binary optimization (QUBO) problem constructed using data ingested from a
commercial mobile network, and solve it using a cloud-based commercially
available quantum computing platform. Results show that quantum annealing
solver can successfully assign conflict-free RSIs. Comparison with well-known
heuristics reveals that some classic algorithms are even more effective in
terms of solution quality and computation time. The non-quantum advantage is
due to the fact that current implementation is a semi-quantum proof-of-concept
algorithm. Also, the results depend on the type of quantum computer used.
Nevertheless, the proposed framework is highly flexible and holds tremendous
potential for harnessing the power of quantum computing in mobile network
automation.
| [
"cs.NI",
"cs.AI"
] | cs.NI | cs.AI | Networking and Internet Architecture;Artificial Intelligence | 4,713Networking and Internet Architecture;Artificial Intelligence
|
1705.00182 | In the paper we consider Lamperti type theorems for random fields. Together
with known results we present some new results on ${\mathbb R}^m$-valued
self-similar fields $\{{\bf X} ({\bf t}), \ {\bf t} \in {\mathbb R}^d \}$,
their domains of attraction and the so-called Lamperti transformations,
expressing the relation between self-similarity and stationarity. Also we
investigate regularly and slowly varying functions of several variables.
| [
"math.PR"
] | math.PR | Probability | 5,709Probability
|
|
physics/0003019 | The aim of the Swedish-Japanese EISCAT campaign in February 1999 was to
measure the ionospheric parameters inside and outside the auroral arcs. The ion
line radar experiment was optimised to probe the E-region and lower F-region
with as high a speed as possible. Two extra channels were used for the plasma
line measurements covering the same altitudes, giving a total of 3 upshifted
and 3 downshifted frequency bands of 25 kHz each. For most of the time the
shifted channels were tuned to 3 (both), 4 (up), 5.5 (down) and 6.5 (both) MHz.
Weak signals are seen whenever the radar is probing the diffuse aurora,
corresponding to the relatively low plasma frequencies. At times when auroral
arcs pass the radar beam, significant increases in return power are observed.
Many cases with simultaneously up and down shifted plasma lines are recorded.
In spite of the rather active environment, the highly optimised measurements
enable investigation of the properties of the plasma lines. A modified
theoretical incoherent scatter spectrum is used to explain the measurements.
The general trend is an upgoing field-aligned current in the diffuse aurora,
confirmed with a full fit of the combined ion and plasma line spectra. There
are also cases with strong suprathermal currents indicated by large differences
in signal strength between up- and downshifted plasma lines.
| [
"physics.space-ph"
] | physics.space-ph | Space Physics | 6,764Space Physics
|
|
2002.04086 | In this note, we propose a method to under-approximate finite-time reachable
sets and tubes for a class of continuous-time linear uncertain systems. The
class under consideration is the linear time-varying (LTV) class with
integrable time-varying system matrices and uncertain initial and input values
belonging to known convex compact sets. The proposed method depends upon the
iterative use of constant-input reachable sets which results in convergent
under-approximations in the sense of Hausdorff distance. We illustrate our
approach through two numerical examples.
| [
"eess.SY",
"cs.NA",
"cs.SY",
"math.NA"
] | eess.SY | cs.NA | Systems and Control;Numerical Analysis;Systems and Control;Numerical Analysis | 7,205Systems and Control;Numerical Analysis;Systems and Control;Numerical Analysis
|
0901.2239 | The probability distribution function (PDF) tails of the zonal flow structure
formation and the PDF tails of momentum flux by incorporating effect of a shear
flow in ion-temperature-gradient (ITG) turbulence are computed in the present
paper. The bipolar vortex soliton (modon) is assumed to be the coherent
structure responsible for bursty and intermittent events driving the PDF tails.
It is found that stronger zonal flows are generated in ITG turbulence than
Hasegawa-Mima (HM) turbulence as well as further from marginal stability. This
suggests that although ITG turbulence has a higher level of heat flux, it also
more likely generates stronger zonal flows, leading to a self-regulating
system. It is also shown that shear flows can significantly reduce the PDF
tails of Reynolds stress and structure formation.
| [
"physics.plasm-ph",
"physics.flu-dyn"
] | physics.plasm-ph | physics.flu-dyn | Plasma Physics;Fluid Dynamics | 5,578Plasma Physics;Fluid Dynamics
|
1903.06603 | This work studies the robustness certification problem of neural network
models, which aims to find certified adversary-free regions as large as
possible around data points. In contrast to the existing approaches that seek
regions bounded uniformly along all input features, we consider non-uniform
bounds and use it to study the decision boundary of neural network models. We
formulate our target as an optimization problem with nonlinear constraints.
Then, a framework applicable for general feedforward neural networks is
proposed to bound the output logits so that the relaxed problem can be solved
by the augmented Lagrangian method. Our experiments show the non-uniform bounds
have larger volumes than uniform ones and the geometric similarity of the
non-uniform bounds gives a quantitative, data-agnostic metric of input
features' robustness. Further, compared with normal models, the robust models
have even larger non-uniform bounds and better interpretability.
| [
"cs.LG",
"stat.ML"
] | cs.LG | stat.ML | Machine Learning;Machine Learning | 4,163Machine Learning;Machine Learning
|
1911.05315 | The classical inequality of Bohr asserts that if a power series converges in
the unit disk and its sum has modulus less than or equal to $1$, then the sum
of absolute values of its terms is less than or equal to $1$ for the subdisk
$|z|<1/3$ and $1/3$ is the best possible constant. Recently, there has been a
number of investigations on this topic. In this article, we present a refined
version of Bohr's inequality along with few other related improved versions of
previously known results.
| [
"math.CV"
] | math.CV | Complex Variables | 1,135Complex Variables
|
|
0904.3081 | Based on measurements with the Effelsberg 100-m telescope, a multi-line study
of molecular species is presented toward the gravitational lens system
PKS1830-211. Obtaining average radial velocities and performing Large Velocity
Gradient radiative transfer calculations, the aims of this study are (1) to
determine the density of the gas, (2) to constrain the temperature of the
cosmic microwave background, and (3) to evaluate the proton-to-electron mass
ratio at redshift 0.9. Analyzing data from six rotational HC3N transitions
(this includes the J=7-6 line, which is likely detected for the first time in
the interstellar medium) we obtain about 2000 cm-3 for the gas density of the
south-western absorption component. Again toward the south-western source,
excitation temperatures of molecular species with optically thin lines and
higher rotational constants are, on average, consistent with the expected
temperature of the cosmic microwave background, T_CMB = 5.14 K. However,
individually, there is a surprisingly large scatter which far surpasses
expected uncertainties. A comparison of CS J=1-0 and 4-3 optical depths toward
the weaker north-western absorption component results in an excitation
temperature of 11 K and a 1-sigma error of 3 K. For the south-eastern main
component, a comparison of velocities determined from ten optically thin NH3
inversion lines with those from five optically thin rotational transitions of
HC3N, observed at similar frequencies, constrains potential variations of the
proton-to-electron mass ratio, with respect to its present value, to <1.4 x
10^-6 with 3-sigma confidence. Also including optically thin rotational lines
from other molecular species, it is emphasized that systematic errors are
smaller than 1 km/s, corresponding to an uncertainty of 10-6.
| [
"astro-ph.CO"
] | astro-ph.CO | Cosmology and Nongalactic Astrophysics | 1,725Cosmology and Nongalactic Astrophysics
|
|
1012.5934 | We compare different methods for performing analytical continuation of
spectral data from the imaginary time or frequency axis to the real frequency
axis for the optical conductivity sigma(omega). We compare the maximum entropy
(MaxEnt), singular value decomposition (SVD), sampling and Pade methods for
analytical continuation. We also study two direct methods for obtaining
sigma(0). For the MaxEnt approach we focus on a recent modification. The data
are split up in batches, a separate MaxEnt calculation is done for each batch
and the results are averaged. For the problems studied here, we find that
typically the SVD, sampling and modified MaxEnt methods give comparable
accuracy, while the Pade approximation is usually less reliable.
| [
"cond-mat.str-el",
"physics.data-an"
] | cond-mat.str-el | physics.data-an | Strongly Correlated Electrons;Data Analysis, Statistics and Probability | 7,267longtail
|
0706.2408 | Unexpected spectral features are observed in the two photon spectrum of the
pure water in the forward direction when an 80 femtosecond laser pulse is
focused at 10^10Wcm-2 or less. Such intensity is much lower than the breakdown
or stimulated threshold of the liquid water. The two broad features are about
2700cm-1 and 5000cm-1 red shifted from the hyper-Rayleigh wavelength,
respectively, and they are quadratic with the laser intensity. They do not
match the known Raman or hyper-Raman frequencies of water, and they are both
centered at a narrow angle in the forward direction. Several other liquids also
exhibited similar but molecular specific spectral features.
| [
"physics.chem-ph",
"physics.optics"
] | physics.chem-ph | physics.optics | Chemical Physics;Optics | 911Chemical Physics;Optics
|
1801.02593 | We propose a scalable ion trap architecture for universal quantum
computation, which is composed of an array of ion traps with one ion confined
in each trap. The neighboring traps are designed capable of merging into one
single trap. The universal two-qubit $\sqrt{SWAP}$ gate is realized by direct
collision of two neighboring ions in the merged trap, which induces an
effective spin-spin interaction between two ions. We find that the
collision-induced spin-spin interaction decreases with the third power of two
ions' trapping distance. Even with a $200\ \mu m$ trapping distance between
atomic ions in Paul traps, it is still possible to realize a two-qubit gate
operation with speed in $0.1\ kHz$ regime. The speed can be further increased
up into $0.1\ MHz$ regime using electrons with $10\ mm$ trapping distance in
Penning traps.
| [
"quant-ph",
"cond-mat.mes-hall",
"physics.app-ph",
"physics.atom-ph"
] | quant-ph | cond-mat.mes-hall | Quantum Physics;Mesoscale and Nanoscale Physics;Applied Physics;Atomic Physics | 7,267longtail
|
1212.5886 | We have performed angle-resolved photoemission spectroscopy of the strongly
spin-orbit coupled low-carrier density superconductor Sn1-xInxTe (x = 0.045) to
elucidate the electronic states relevant to the possible occurrence of
topological superconductivity recently reported for this compound from
point-contact spectroscopy. The obtained energy-band structure reveals a small
holelike Fermi surface centered at the L point of the bulk Brillouin zone,
together with a signature of a topological surface state which indicates that
this superconductor is essentially a doped topological crystalline insulator
characterized by band inversion and mirror symmetry. A comparison of the
electronic states with a band-non-inverted superconductor possessing a similar
Fermi surface structure, Pb1-xTlxTe, suggests that the anomalous behavior in
the superconducting state of Sn1-xInxTe is likely to be related to the peculiar
orbital characteristics of the bulk valence band and/or the presence of a
topological surface state.
| [
"cond-mat.mes-hall",
"cond-mat.str-el",
"cond-mat.supr-con"
] | cond-mat.mes-hall | cond-mat.str-el | Mesoscale and Nanoscale Physics;Strongly Correlated Electrons;Superconductivity | 4,551Mesoscale and Nanoscale Physics;Strongly Correlated Electrons;Superconductivity
|
2104.13860 | We study the 3-\textsc{Coloring} problem in graphs with small diameter. In
2013, Mertzios and Spirakis showed that for $n$-vertex diameter-2 graphs this
problem can be solved in subexponential time $2^{\mathcal{O}(\sqrt{n \log
n})}$. Whether the problem can be solved in polynomial time remains a
well-known open question in the area of algorithmic graphs theory.
In this paper we present an algorithm that solves 3-\textsc{Coloring} in
$n$-vertex diameter-2 graphs in time $2^{\mathcal{O}(n^{1/3} \log^{2} n)}$.
This is the first improvement upon the algorithm of Mertzios and Spirakis in
the general case, i.e., without putting any further restrictions on the
instance graph.
In addition to standard branchings and reducing the problem to an instance of
2-\textsc{Sat}, the crucial building block of our algorithm is a combinatorial
observation about 3-colorable diameter-2 graphs, which is proven using a
probabilistic argument.
As a side result, we show that 3-\textsc{Coloring} can be solved in time
$2^{\mathcal{O}( (n \log n)^{2/3})}$ in $n$-vertex diameter-3 graphs. We also
generalize our algorithms to the problem of finding a list homomorphism from a
small-diameter graph to a cycle.
| [
"cs.DS",
"cs.DM"
] | cs.DS | cs.DM | Data Structures and Algorithms;Discrete Mathematics | 1,938Data Structures and Algorithms;Discrete Mathematics
|
1109.6810 | This article studies the sequence of iterative degrees of a birational map of
the plane. This sequence is known either to be bounded or to have a linear,
quadratic or exponential growth. The classification elements of infinite order
with a bounded sequence of degrees is achieved, the case of elements of finite
order being already known. The coefficients of the linear and quadratic growth
are then described, and related to geometrical properties of the map. The
dynamical number of base-points is also studied. Applications of our results
are the description of embeddings of the Baumslag-Solitar groups and GL(2,Q)
into the Cremona group.
| [
"math.AG",
"math.DS"
] | math.AG | math.DS | Algebraic Geometry;Dynamical Systems | 107Algebraic Geometry;Dynamical Systems
|
astro-ph/0403526 | Good tracking requires that the quintessence energy fraction slowly increase
while the roll $\lambda\equiv -d\ln V/\varkappa d\phi$ slowly decreases, but is
not yet truly slow-rolling. The supernova bound on the present quintessence
equation of state requires either (1) a cosmological constant or other
fine-tuned "crawling quintessence" or (2) "roll-over quintessence" that tracked
until recently, but now became slow rolling, because of a sharp increase in
potential curvature. Thus, fine-tuning is required by constant equation of
state and inverse power potentials, but can be avoided by the SUGRA and
Skordis-Albrecht potentials and other good trackers, provided quintessence
energy domination and slow roll {\em both} began only recently. This makes the
time in which we live special in {\em two} respects.
| [
"astro-ph"
] | astro-ph | Astrophysics | 463Astrophysics
|
|
2007.14465 | We explain theoretically how to reconstruct the 3D scene from successive
frames in order to see the video in 3D. To do this, features, associated to
moving rigid objects in 3D, are extracted in frames and matched. The vanishing
point computed in frame corresponding to the direction of moving object is used
for 3D positioning of the 3D structure of the moving object. First experiments
are conducted and the obtained results are shown and publicly available. They
demonstrate the feasibility of our method. We conclude this paper by future
works in order to improve this method tacking into account non-rigid objects
and the case of moving camera.
| [
"cs.CV"
] | cs.CV | Computer Vision and Pattern Recognition | 1,498Computer Vision and Pattern Recognition
|
|
1109.6251 | Observations of dust polarized emission toward star forming regions trace the
magnetic field component in the plane of the sky and provide constraints to
theoretical models of cloud collapse. We compare high-angular resolution
observations of the submillimeter polarized emission of the low-mass
protostellar source NGC 1333 IRAS 4A with the predictions of three different
models of collapse of magnetized molecular cloud cores. We compute the Stokes
parameters for the dust emission for the three models. We then convolve the
results with the instrumental response of the Submillimeter Array observation
toward IRAS 4A. Finally, we compare the synthetic maps with the data, varying
the model parameters and orientation, and we assess the quality of the fit by a
\chi^2 analysis. High-angular resolution observations of polarized dust
emission can constraint the physical properties of protostars. In the case of
IRAS 4A, the best agreements with the data is obtained for models of collapse
of clouds with mass-to-flux ratio >2 times the critical value, initial uniform
magnetic field of strength ~0.5 mG, and age of the order of a few 10^4 yr since
the onset of collapse. Magnetic dissipation, if present, is found to occur
below the resolution level of the observations. Including a previously measured
temperature profile of IRAS 4A leads to a more realistic morphology and
intensity distribution. We also show that ALMA has the capability of
distinguishing among the three different models adopted in this work. Our
results are consistent with the standard theoretical scenario for the formation
of low-mass stars, where clouds initially threaded by large-scale magnetic
fields become unstable and collapse, trapping the field in the nascent
protostar and the surrounding circumstellar disk. In the collapsing cloud, the
dynamics is dominated by gravitational and magnetic forces.
| [
"astro-ph.GA",
"astro-ph.IM",
"astro-ph.SR"
] | astro-ph.GA | astro-ph.IM | Astrophysics of Galaxies;Instrumentation and Methods for Astrophysics;Solar and Stellar Astrophysics | 499Astrophysics of Galaxies;Instrumentation and Methods for Astrophysics;Solar and Stellar Astrophysics
|
1304.0921 | We propose a simple renormalizable model for the spontaneous CP violation
based on $SU(2)_{L}\times U(1)_{Y}\times A_{4}$ symmetry in a radiative seesaw
mechanism, which can be guaranteed by an extra $Z_{2}$ symmetry. In our model
CP is spontaneously broken at high energies, after breaking of flavor symmetry,
by a complex vacuum expectation value of $A_{4}$-triplet and gauge singlet
scalar field. We show that the spontaneously generated CP phase could become a
natural source of leptogenesis, %CP violation for neutrino oscillation and
leptogenesis, respectively. Then, and also investigate CP violation at low
energies in the lepton sector and show how the CP phases in PMNS could be
arisen through spontaneous symmetry breaking mechanism.
As a numerical study, interestingly, we show that the normal mass hierarchy
favors relatively large values of $\theta_{13}$, large deviations from
maximality of $\theta_{23}<\pi/4$ and Dirac-CP phase
$0^{\circ}\leq\delta_{CP}\leq50^{\circ}$ and
$300^{\circ}\leq\delta_{CP}\leq360^{\circ}$. For the inverted hierarchy case,
the experimentally measured values of $\theta_{13}$ favors $\theta_{23}>\pi/4$
and discrete values of $\delta_{CP}$ around
$100^{\circ},135^{\circ},255^{\circ}$ and $300^{\circ}$. Finally, with a
successful leptogenesis our numerical results give more predictive values on
the Dirac CP phase: for the normal mass hierarchy
$1^{\circ}\lesssim\delta_{CP}\lesssim10^{\circ}$ and for inverted one
$\delta_{CP}\sim100^{\circ},135^{\circ},300^{\circ}$.
| [
"hep-ph"
] | hep-ph | High Energy Physics - Phenomenology | 3,129High Energy Physics - Phenomenology
|
|
2103.09139 | A $[k,n,1]$-graph is a $k$-partite graph with parts of order $n$ such that
the bipartite graph induced by any pair of parts is a matching. An independent
transversal in such a graph is an independent set that intersects each part in
a single vertex. A factor of independent transversals is a set of $n$
pairwise-disjoint independent transversals. Let $f(k)$ be the smallest integer
$n_0$ such that every $[k,n,1]$-graph has a factor of independent transversals
assuming $n \ge n_0$. Several known conjectures imply that for $k \ge 2$,
$f(k)=k$ if $k$ is even and $f(k)=k+1$ if $k$ is odd. While a simple greedy
algorithm based on iterating Hall's Theorem shows that $f(k) \le 2k-2$, no
better bound is known and in fact, there are instances showing that the bound
$2k-2$ is tight for the greedy algorithm. Here we significantly improve upon
the greedy algorithm bound and prove that $f(k) \le 1.78k$ for all $k$
sufficiently large, answering a question of MacKeigan.
| [
"math.CO"
] | math.CO | Combinatorics | 1,014Combinatorics
|
|
2003.08949 | The Simons Observatory (SO) is an upcoming polarization-sensitive Cosmic
Microwave Background (CMB) experiment on the Cerro Toco Plateau (Chile) with
large overlap with other optical and infrared surveys (e.g., DESI, LSST, HSC).
To enable the readout of \bigO(10,000) detectors in each of the four telescopes
of SO, we will employ the microwave SQUID multiplexing technology. With a
targeted multiplexing factor of \bigO{(1,000)}, microwave SQUID multiplexing
has never been deployed on the scale needed for SO. Here we present the design
of the cryogenic coaxial cable and RF component chain that connects room
temperature readout electronics to superconducting resonators that are coupled
to Transition Edge Sensor bolometers operating at sub-Kelvin temperatures. We
describe design considerations including cryogenic RF component selection,
system linearity, noise, and thermal power dissipation.
| [
"astro-ph.IM",
"physics.ins-det"
] | astro-ph.IM | physics.ins-det | Instrumentation and Methods for Astrophysics;Instrumentation and Detectors | 3,754Instrumentation and Methods for Astrophysics;Instrumentation and Detectors
|
2302.09720 | We derive a formula for the velocity distribution of an axially symmetric
galaxy where the mass density is corrected using the mass formula from special
relativity. We take some reasonable test mass densities and numerically compute
the resulting galaxy rotation curves. We then compare these to the rotation
curves obtained from a similar formula without a relativistic correction
factor. We find that the correction factor has a small dark-matter like effect.
Finally, we compare these to the corresponding Keplerian velocity curves. We
find that there is a large discrepancy in this case, where away from the
galactic center, up to the galactic edge, the curves computed using our
formulas give a noticeably higher velocity.
| [
"gr-qc",
"astro-ph.GA"
] | gr-qc | astro-ph.GA | General Relativity and Quantum Cosmology;Astrophysics of Galaxies | 2,678General Relativity and Quantum Cosmology;Astrophysics of Galaxies
|
2307.08696 | In this note, we compute the reproducing kernel for the RKHS of functions on
$\mathbb{R}^n$ in a sufficiently high Sobolev norm.
| [
"math.CA"
] | math.CA | Classical Analysis and ODEs | 934Classical Analysis and ODEs
|
|
2209.08126 | The exploration of the QCD phase diagram is the goal of many experiments in
the world. The low net baryon density region is relatively well studied, while
the one corresponding to higher net densities still contains multiple
unrevealed puzzles getting significant attention. In multiple experimental
complexes such as STAR or HADES, the heavy ions collide at relatively lower
energies than those obtained at LHC, creating "not the hottest soup" of nuclear
matter. The examination of it provides unique insights into understanding the
properties of matter production and its transitions. In this paper, several of
the significant experimental discoveries are reviewed.
| [
"nucl-ex",
"hep-ex"
] | nucl-ex | hep-ex | Nuclear Experiment;High Energy Physics - Experiment | 4,863Nuclear Experiment;High Energy Physics - Experiment
|
2205.13410 | There is a growing interest in developing data-driven reduced-order models
for atmospheric and oceanic flows that are trained on data obtained either from
high-resolution simulations or satellite observations. The data-driven models
are non-intrusive in nature and offer significant computational savings
compared to large-scale numerical models. These low-dimensional models can be
utilized to reduce the computational burden of generating forecasts and
estimating model uncertainty without losing the key information needed for data
assimilation to produce accurate state estimates. This paper aims at exploring
an equation-free surrogate modeling approach at the intersection of machine
learning and data assimilation in Earth system modeling. With this objective,
we introduce an end-to-end non-intrusive reduced-order modeling (NIROM)
framework equipped with contributions in modal decomposition, time series
prediction, optimal sensor placement, and sequential data assimilation.
Specifically, we use proper orthogonal decomposition (POD) to identify the
dominant structures of the flow, and a long short-term memory network to model
the dynamics of the POD modes. The NIROM is integrated within the deterministic
ensemble Kalman filter (DEnKF) to incorporate sparse and noisy observations at
optimal sensor locations obtained through QR pivoting. The feasibility and the
benefit of the proposed framework are demonstrated for the NOAA Optimum
Interpolation Sea Surface Temperature (SST) V2 dataset. Our results indicate
that the NIROM is stable for long-term forecasting and can model dynamics of
SST with a reasonable level of accuracy. Furthermore, the prediction accuracy
of the NIROM gets improved by one order of magnitude by the DEnKF algorithm.
This work provides a way forward toward transitioning these methods to fuse
information from Earth system models and observations to achieve accurate
forecasts.
| [
"physics.flu-dyn"
] | physics.flu-dyn | Fluid Dynamics | 2,452Fluid Dynamics
|
|
2012.13051 | We address the fully-developed wrinkle pattern formed upon stretching a
Hookean, rectangular-shaped sheet, when the longitudinal tensile load induces
transverse compression that far exceeds the stability threshold of a purely
planar deformation. At this "far from threshold" parameter regime, which has
been the subject of the celebrated Cerda-Mahadevan (CM) model, the wrinkle
pattern expands throughout the length of the sheet and the characteristic
wavelength of undulations is much smaller than its width. Employing Surface
Evolver simulations over a range of sheet thicknesses and tensile loads we
elucidate the theoretical underpinnings of the far-from-threshold framework in
this set-up. We show that the evolution of wrinkles comes in tandem with
collapse of transverse compressive stress, rather than vanishing transverse
strain, such that the stress field approaches asymptotically a compression-free
limit, describable by tension field theory. We compute the compression-free
stress field by simulating a Hookean sheet that has finite stretching modulus
but no bending rigidity, and show that this singular limit encapsulates the
geometrical nonlinearity underlying the amplitude-wavelength ratio of wrinkle
patterns in physical, highly bendable sheets, even though the actual strains
may be so small that the local mechanics is perfectly Hookean. Finally, we
revisit the balance of bending and stretching energies that gives rise to a
favorable wrinkle wavelength, and study the consequent dependence of the
wavelength on the tensile load as well as the thickness and length of the
sheet.
| [
"cond-mat.soft"
] | cond-mat.soft | Soft Condensed Matter | 6,537Soft Condensed Matter
|
|
hep-ph/0605313 | The PVLAS signal has renewed the interest in light bosons coupled to the
electromagnetic field. However, astrophysical bounds coming from the lifetime
of the sun and the CAST experiment are seemingly in conflict with this result.
We discuss effective models that allow to suppress production of axion-like
particles in the sun and thereby relax the bounds by some orders of magnitude.
This stresses the importance of laboratory searches.
| [
"hep-ph"
] | hep-ph | High Energy Physics - Phenomenology | 3,129High Energy Physics - Phenomenology
|
|
1010.5241 | There is a standard story about decay in multi-dimensional flux landscapes:
that from any state, the fastest decay is to take a small step, discharging one
flux unit at a time; that fluxes with the same coupling constant are
interchangeable; and that states with N units of a given flux have the same
decay rate as those with -N. We show that this standard story is false. The
fastest decay is a giant leap that discharges many different fluxes in unison;
this decay is mediated by a 'minimal' brane that wraps the internal manifold
and exhibits behavior not visible in the effective theory. We discuss the
implications for the cosmological constant.
| [
"hep-th",
"gr-qc"
] | hep-th | gr-qc | High Energy Physics - Theory;General Relativity and Quantum Cosmology | 3,321High Energy Physics - Theory;General Relativity and Quantum Cosmology
|
1108.4747 | This edition of the Australian Astronomical Observatory Observer contains
articles on the commissioning of the new SAMI instrument giving the first
hexabundle galaxy spectra; galaxy parameter variations across and through the
6dFGS Fundamental Plane; an introduction to the new Dragonfly stellar
interferometer; an update on the RAdial VElocity (RAVE) survey at half a
million spectra; the Magellanic Quasars Survey; the Integrated Photonic
Spectrograph's first look at the heart of the Scorpion; using AAOMega to
measure the age of the young open cluster IC2602; making MANIFEST fibres for
the Giant Magellan Telescope and a Voyage through Filaments of Galaxies. The
Observer also contains thoughts on diversity in the astronomy community and
reports on the recent Supernovae and their Host Galaxies conference and the
2011 Science Meets Parliament. In addition there are the usual features of the
AUSGO Corner, Epping News and Letter from Coona.
| [
"astro-ph.IM",
"astro-ph.CO",
"astro-ph.GA",
"astro-ph.SR"
] | astro-ph.IM | astro-ph.CO | Instrumentation and Methods for Astrophysics;Cosmology and Nongalactic Astrophysics;Astrophysics of Galaxies;Solar and Stellar Astrophysics | 3,710Instrumentation and Methods for Astrophysics;Cosmology and Nongalactic Astrophysics;Astrophysics of Galaxies;Solar and Stellar Astrophysics
|
1204.3499 | We discuss the SM-like Higgs boson mass in the MSSM in an R-invariant direct
gauge mediation model with the gravitino mass in the O(1) keV range. The
gravitino dark matter scenario in this mass range is a good candidate for a
slightly warm dark matter. We show that the Higgs boson mass around 125 GeV
suggested by the ATLAS and CMS experiments can be easily achieved in the direct
gauge mediation model with this gravitino mass range.
| [
"hep-ph"
] | hep-ph | High Energy Physics - Phenomenology | 3,129High Energy Physics - Phenomenology
|
|
1601.03154 | Explicit dependencies of the local density of states and the magnetization
local density of states have been obtained around magnetic point defects in a
two-dimensional electron gas with Rashba spin-orbit interaction . The
expressions are given in the Born approximation for arbitrary magnitude and
orientation of the defect magnetic moment, and for arbitrary size of the
constant of spin-orbit interaction alpha/. On the basis of our asymptotically
exact formulas a procedure for the determination of the constant alpha/ in STM
experiments is proposed. The novel analytical results are compared with the
numerical and approximate results of previous work. At variance with earlier
work we find that that magnetic scattering in the presence of spin-orbit
interaction does not modify the local density of states and that the spin
texture resulting from in-plain orientation of the defect magnetic moment, and
elastic scattering, is not a purely in-plane spin texture.
| [
"cond-mat.mes-hall"
] | cond-mat.mes-hall | Mesoscale and Nanoscale Physics | 4,450Mesoscale and Nanoscale Physics
|
|
1609.06606 | A spectral sequence is defined which converges to the \v{C}ech cohomology of
the Euclidean hull of a tiling of the plane with Euclidean finite local
complexity. The terms of the second page are determined by the so-called ePE
homology and ePE cohomology groups of the tiling, and the only potentially
non-trivial boundary map has a simple combinatorial description in terms of its
local patches. Using this spectral sequence, we compute the \v{C}ech cohomology
of the Euclidean hull of the Penrose tilings.
| [
"math.AT",
"math.DS",
"math.GN"
] | math.AT | math.DS | Algebraic Topology;Dynamical Systems;General Topology | 7,267longtail
|
1904.13393 | We firstly discuss classical stability for a dynamical system of two ions
levitated in a 3D Radio-Frequency (RF) trap, assimilated with two coupled
oscillators. We obtain the solutions of the coupled system of equations that
characterizes the associated dynamics. In addition, we supply the modes of
oscillation and demonstrate the weak coupling condition is inappropriate in
practice, while for collective modes of motion (and strong coupling) only a
peak of the mass can be detected. Phase portraits and power spectra are
employed to illustrate how the trajectory executes quasiperiodic motion on the
surface of torus, namely a Kolmogorov-Arnold-Moser (KAM) torus. In an attempt
to better describe dynamical stability of the system, we introduce a model that
characterizes dynamical stability and the critical points based on the Hessian
matrix approach. The model is then applied to investigate quantum dynamics for
many-body systems consisting of identical ions, levitated in 2D and 3D ion
traps. Finally, the same model is applied to the case of a combined 3D
Quadrupole Ion Trap (QIT) with axial symmetry, for which we obtain the
associated Hamilton function. The ion distribution can be described by means of
numerical modeling, based on the Hamilton function we assign to the system. The
approach we introduce is effective to infer the parameters of distinct types of
traps by applying a unitary and coherent method, and especially for identifying
equilibrium configurations, of large interest for ion crystals or quantum
logic.
| [
"physics.atom-ph",
"nlin.CD",
"nlin.SI",
"physics.comp-ph"
] | physics.atom-ph | nlin.CD | Atomic Physics;Chaotic Dynamics;Exactly Solvable and Integrable Systems;Computational Physics | 7,267longtail
|
1507.03966 | Detailed characterization of an extrasolar planet's atmosphere provides the
best hope for distinguishing the makeup of its outer layers, and the only hope
for understanding the interplay between initial composition, chemistry,
dynamics & circulation, and disequilibrium processes. In recent years, some
areas have seen rapid progress while developments in others have come more
slowly and/or have been hotly contested. This article gives an observer's
perspective on the current understanding of extrasolar planet atmospheres prior
to the considerable advances expected from the next generation of observing
facilities. Atmospheric processes of both transiting and directly-imaged
planets are discussed, including molecular and atomic abundances, cloud
properties, thermal structure, and planetary energy budgets. In the future we
can expect a continuing and accelerating stream of new discoveries, which will
fuel the ongoing exoplanet revolution for many years to come.
| [
"astro-ph.EP",
"astro-ph.IM"
] | astro-ph.EP | astro-ph.IM | Earth and Planetary Astrophysics;Instrumentation and Methods for Astrophysics | 2,376Earth and Planetary Astrophysics;Instrumentation and Methods for Astrophysics
|
0901.4580 | We modify the Relative State Interpretation (RSI) of Quantum Mechanics so
that it does not imply many worlds and parallel realities. We drop the
assumption that probability amplitudes correspond one-to-one with reality: Not
all information is contained in amplitudes, and not all amplitudes need be
realized. Amplitudes do not "collapse" after a measurement, but evolve
continuously, including unrealized ones. After each "event" only one possible
outcome is realized. Therefore, if a value is measured, that value is real, all
others are not; there is only one reality and one world. Reality content is
"quantized" : unity for realized outcomes, zero for all others. It is
"conserved": can move along any possible sequence of events, but only one at a
time. The modified RSI is is strictly deterministic in the sense that the
"global" probability amplitudes of the universe are determined for all times by
the laws of physics and the initial conditions. They guide all events. But it
is not deterministic in the sense that from the amplitudes one can not predict
which outcome actually happens; that represents new information that
accumulates as history unfolds. To the extent that information is part of the
physical world, the coming into being of the universe is ongoing, even after
the Big Bang. All predictions of the two versions agree, except possibly in
esoteric, untested cases.
| [
"quant-ph"
] | quant-ph | Quantum Physics | 5,985Quantum Physics
|
|
1901.02209 | In the \textsc{Subset Feedback Vertex Set (Subset-FVS)} problem the input is
a graph $G$, a subset \(T\) of vertices of \(G\) called the `terminal'
vertices, and an integer $k$. The task is to determine whether there exists a
subset of vertices of cardinality at most $k$ which together intersect all
cycles which pass through the terminals. \textsc{Subset-FVS} generalizes
several well studied problems including \textsc{Feedback Vertex Set} and
\textsc{Multiway Cut}. This problem is known to be \NP-Complete even in split
graphs. Cygan et al. proved that \textsc{Subset-FVS} is fixed parameter
tractable (\FPT) in general graphs when parameterized by $k$ [SIAM J. Discrete
Math (2013)]. In split graphs a simple observation reduces the problem to an
equivalent instance of the $3$-\textsc{Hitting Set} problem with same solution
size. This directly implies, for \textsc{Subset-FVS} \emph{restricted to split
graphs}, (i) an \FPT algorithm which solves the problem in $\OhStar(2.076^k)$
time \footnote{The \(\OhStar()\) notation hides polynomial factors.}% for
\textsc{Subset-FVS} in Chordal % Graphs [Wahlstr\"om, Ph.D. Thesis], and (ii) a
kernel of size $\mathcal{O}(k^3)$. We improve both these results for
\textsc{Subset-FVS} on split graphs; we derive (i) a kernel of size
$\mathcal{O}(k^2)$ which is the best possible unless $\NP \subseteq \coNP/{\sf
poly}$, and (ii) an algorithm which solves the problem in time
$\mathcal{O}^*(2^k)$. Our algorithm, in fact, solves \textsc{Subset-FVS} on the
more general class of \emph{chordal graphs}, also in $\mathcal{O}^*(2^k)$ time.
| [
"cs.DS"
] | cs.DS | Data Structures and Algorithms | 1,908Data Structures and Algorithms
|
|
1612.08210 | Neutron(n)-capture elements are produced by s-process nucleosynthesis in low-
and intermediate-mass AGB stars, and therefore can be enriched in planetary
nebulae (PNe). In the last ten years, n-capture elements have been detected in
more than 100 PNe in the Milky Way and nearby galaxies. In some objects,
several different n-capture elements have been detected, providing valuable
constraints to models of AGB nucleosynthesis and evolution. These detections
have motivated theoretical and experimental investigations of the atomic data
needed to derive accurate n-capture element abundances. In this review, I
discuss the methods and results of these atomic data studies, and their
application to abundance determinations in PNe.
| [
"astro-ph.SR"
] | astro-ph.SR | Solar and Stellar Astrophysics | 6,668Solar and Stellar Astrophysics
|
|
2201.01730 | The DART spacecraft will impact Didymos's secondary, Dimorphos, at the end of
2022 and cause a change in the orbital period of the secondary. For simplicity,
most previous numerical simulations of the impact used a spherical projectile
geometry to model the DART spacecraft. To investigate the effects of
alternative, simple projectile geometries on the DART impact outcome we used
the iSALE shock physics code in two and thee-dimensions to model vertical
impacts of projectiles with a mass and speed equivalent to the nominal DART
impact, into porous basalt targets. We found that the simple projectile
geometries investigated here have minimal effects on the crater morphology and
momentum enhancement. Projectile geometries modelled in two-dimensions that
have similar surface areas at the point of impact, affect the crater radius and
the crater volume by less than 5%. In the case of a more extreme projectile
geometry (i.e., a rod, modelled in three-dimensions), the crater was elliptical
and 50% shallower compared to the crater produced by a spherical projectile of
the same momentum. The momentum enhancement factor in these test cases,
commonly referred to as beta, was within 7% for the 2D simulations and within
10% for the 3D simulations, of the value obtained for a uniform spherical
projectile. The most prominent effects of projectile geometry are seen in the
ejection velocity as a function of launch position and ejection angle of the
fast ejecta that resides in the so-called `coupling zone'. These results will
inform the LICIACube ejecta cone analysis.
| [
"astro-ph.EP"
] | astro-ph.EP | Earth and Planetary Astrophysics | 2,351Earth and Planetary Astrophysics
|
|
1506.07147 | Let $R$ be a semilocal Dedekind domain. Under certain assumptions, we show
that two (not necessarily unimodular) hermitian forms over an $R$-algebra with
involution, which are rationally ismorphic and have isomorphic semisimple
coradicals, are in fact isomorphic. The same result is also obtained for
quadratic forms equipped with an action of a finite group. The results have
cohomological restatements that resemble the Grothendieck--Serre conjecture,
except the group schemes involved are not reductive. We show that these group
schemes are closely related to group schemes arising in Bruhat--Tits theory.
| [
"math.RA"
] | math.RA | Rings and Algebras | 6,272Rings and Algebras
|
|
0909.1072 | We study envy-free mechanisms for scheduling tasks on unrelated machines
(agents) that approximately minimize the makespan. For indivisible tasks, we
put forward an envy-free poly-time mechanism that approximates the minimal
makespan to within a factor of $O(\log m)$, where $m$ is the number of
machines. We also show a lower bound of $\Omega(\log m / \log\log m)$. This
improves the recent result of Hartline {\sl et al.} \cite{Ahuva:2008} who give
an upper bound of $(m+1)/2$, and a lower bound of $2-1/m$. For divisible tasks,
we show that there always exists an envy-free poly-time mechanism with optimal
makespan.
| [
"cs.GT"
] | cs.GT | Computer Science and Game Theory | 1,449Computer Science and Game Theory
|
|
1210.5816 | We present extensive first-principles calculations on the inverse
full-Heusler compounds having the chemical formula X$_2$YZ where (X = Sc, Ti,
V, Cr or Mn), (Z = Al, Si or As) and the Y ranges from Ti to Zn. Several of
these alloys are identified to be half-metallic magnets. We show that the
appearance of half-metallicity is associated in all cases to a Slater-Pauling
behavior of the total spin-magnetic moment. There are three different variants
of this rule for the inverse Heusler alloys depending on the chemical type of
the constituent transition-metal atoms. Simple arguments regarding the
hybridization of the d-orbitals of neighboring atoms can explain these rules.
We expect our results to trigger further experimental interest on this type of
half-metallic Heusler compounds.
| [
"cond-mat.mtrl-sci"
] | cond-mat.mtrl-sci | Materials Science | 4,287Materials Science
|
|
1810.00216 | The statistical properties of Synthetic Aperture Radar (SAR) image texture
reveals useful target characteristics. It is well-known that these images are
affected by speckle, and prone to contamination as double bounce and corner
reflectors. The $\mathcal{G}^0$ distribution is flexible enough to model
different degrees of texture in speckled data. It is indexed by three
parameters: $\alpha$, related to the texture, $\gamma$, a scale parameter, and
$L$, the number of looks which is related to the signal-to-noise ratio. Quality
estimation of $\alpha$ is essential due to its immediate interpretability. In
this article, we compare the behavior of a number of parameter estimation
techniques in the noisiest case, namely single look data. We evaluate them
using Monte Carlo methods for non-contaminated and contaminated data,
considering convergence rate, bias, mean squared error (MSE) and computational
cost. The results are verified with simulated and actual SAR images.
| [
"stat.AP",
"cs.CV"
] | stat.AP | cs.CV | Applications;Computer Vision and Pattern Recognition | 285Applications;Computer Vision and Pattern Recognition
|
2209.06758 | Modular Reconfigurable Robots (MRRs) represent an exciting path forward for
industrial robotics, opening up new possibilities for robot design. Compared to
monolithic manipulators, they promise greater flexibility, improved
maintainability, and cost-efficiency. However, there is no tool or standardized
way to model and simulate assemblies of modules in the same way it has been
done for robotic manipulators for decades. We introduce the Toolbox for
Industrial Modular Robotics (Timor), a Python toolbox to bridge this gap and
integrate modular robotics into existing simulation and optimization pipelines.
Our open-source library offers model generation and task-based configuration
optimization for MRRs. It can easily be integrated with existing simulation
tools - not least by offering URDF export of arbitrary modular robot
assemblies. Moreover, our experimental study demonstrates the effectiveness of
Timor as a tool for designing modular robots optimized for specific use cases.
| [
"cs.RO"
] | cs.RO | Robotics | 6,325Robotics
|
|
1410.5088 | This paper shows that it is possible to reason about the safety and
termination of programs handling potentially cyclic, singly-linked lists using
propositional reasoning even when the safety invariants and termination
arguments depend on constraints over the lengths of lists. For this purpose, we
propose the theory SLH of singly-linked lists with length, which is able to
capture non-trivial interactions between shape and arithmetic. When using the
theory of bit-vector arithmetic as a background, SLH is efficiently decidable
via a reduction to SAT. We show the utility of SLH for software verification by
using it to express safety invariants and termination arguments for programs
manipulating potentially cyclic, singly-linked lists with unrestricted,
unspecified sharing. We also provide an implementation of the decision
procedure and use it to check safety and termination proofs for several
heap-manipulating programs.
| [
"cs.LO"
] | cs.LO | Logic in Computer Science | 3,801Logic in Computer Science
|
|
2010.01970 | The intrinsic orbital Hall effect (OHE), the orbital counterpart of the spin
Hall effect, was predicted and studied theoretically for more than one decade,
yet to be observed in experiments. Here we propose a strategy to convert the
orbital current in OHE to the spin current via the spin-orbit coupling from the
contact. Furthermore, we find that OHE can induce large nonreciprocal
magnetoresistance when employing magnetic contact. Both the generated spin
current and the orbital Hall magnetoresistance can be applied to probe the OHE
in experiments and design orbitronic devices.
| [
"cond-mat.mtrl-sci"
] | cond-mat.mtrl-sci | Materials Science | 4,287Materials Science
|
|
2008.01902 | Transportation networks are highly complex and the design of efficient
traffic management systems is difficult due to lack of adequate measured data
and accurate predictions of the traffic states. Traffic simulation models can
capture the complex dynamics of transportation networks by using limited
available traffic data and can help central traffic authorities in their
decision-making, if appropriate input is fed into the simulator. In this paper,
we design an integrated simulation-prediction system which estimates the
Origin-Destination (OD) matrix of a road network using only flow rate
information and predicts the behavior of the road network in different
simulation scenarios. The proposed system includes an optimization-based OD
matrix generation method, a Neural Network (NN) model trained to predict OD
matrices via the pattern of traffic flow and a microscopic traffic simulator
with a Dynamic Traffic Assignment (DTA) scheme to predict the behavior of the
transportation system. We test the proposed system on the road network of the
central terminal area (CTA) of the Los Angeles International Airport (LAX),
which demonstrates that the integrated traffic simulation-prediction system can
be used to simulate the effects of several real world scenarios such as lane
closures, curbside parking and other changes. The model is an effective tool
for learning the impact and possible benefits of changes in the network and for
analyzing scenarios at a very low cost without disrupting the network.
| [
"eess.SP",
"cs.LG",
"cs.SY",
"eess.SY"
] | eess.SP | cs.LG | Signal Processing;Machine Learning;Systems and Control;Systems and Control | 6,444Signal Processing;Machine Learning;Systems and Control;Systems and Control
|
1805.05430 | The use of biocomposites on a daily basis for industrial products brings to
light the influence of environmental factors on the evolution of mechanical
properties. This aging has a major influence in the lifetime of any product
based on such materials. Among biobased composites, poly(lactic acid)
reinforced with plant fibers are known to be sensitive to hydrothermal aging
due to the intrinsic nature of their components. Although some papers studied
the influence of temperature and water absorption on such materials, so far the
difference between reversible and irreversible effects of aging has been hardly
studied. This distinction is the purpose of this study. Poly(lactic acid)
samples reinforced with various content of flax fibers (0%, 10%, and 30%) were
immersed in water at different temperature (20, 35, and 50{\textdegree}C) up to
51 days. The physical and chemical phenomena responsible for the changes in the
mechanical properties of biocomposites were evaluated. It was observed that
these changes were mainly reversible. However, irreversible effects of aging
turned out to increase drastically with the amount of fiber and the aging
temperature. While hydrolysis drastically deteriorated PLA for longer aging
times, the lifetime of biocomposites was significantly extended (+ 230% at
50{\textdegree}C from 0% to 10% in fiber content) by the presence of fibers
which postponed the failure of PLA.
| [
"physics.app-ph"
] | physics.app-ph | Applied Physics | 319Applied Physics
|
|
2006.01427 | We present Large-scale Known-committee Stake-based Agreement (LaKSA), a
chain-based Proof-of-Stake protocol that is dedicated, but not limited, to
cryptocurrencies. LaKSA minimizes interactions between nodes through
lightweight committee voting, resulting in a simpler, more robust, and more
scalable proposal than competing systems. It also mitigates other drawbacks of
previous systems, such as high reward variance and long confirmation times.
LaKSA can support large numbers of nodes by design, and provides probabilistic
safety guarantees in which a client makes commit decisions by calculating the
probability that a transaction is reverted based on its blockchain view. We
present a thorough analysis of LaKSA and report on its implementation and
evaluation. Furthermore, our new technique of proving safety can be applied
more broadly to other Proof-of-Stake protocols.
| [
"cs.CR"
] | cs.CR | Cryptography and Security | 1,782Cryptography and Security
|
|
2107.10285 | We use the method of Lightcone Conformal Truncation (LCT) to obtain form
factors and spectral densities of local operators $\mathcal{O}$ in $\phi^4$
theory in two dimensions. We show how to use the Hamiltonian eigenstates from
LCT to obtain form factors that are matrix elements of a local operator
$\mathcal{O}$ between single-particle bra and ket states, and we develop
methods that significantly reduce errors resulting from the finite truncation
of the Hilbert space. We extrapolate these form factors as a function of
momentum to the regime where, by crossing symmetry, they are form factors of
$\mathcal{O}$ between the vacuum and a two-particle asymptotic scattering
state. We also compute the momentum-space time-ordered two-point functions of
local operators in LCT. These converge quickly at momenta away from branch
cuts, allowing us to indirectly obtain the time-ordered correlator and the
spectral density at the branch cuts. We focus on the case where the local
operator $\mathcal{O}$ is the trace $\Theta$ of the stress tensor.
| [
"hep-th",
"cond-mat.str-el",
"hep-lat"
] | hep-th | cond-mat.str-el | High Energy Physics - Theory;Strongly Correlated Electrons;High Energy Physics - Lattice | 3,413High Energy Physics - Theory;Strongly Correlated Electrons;High Energy Physics - Lattice
|
math/0403312 | In connection with the classical Schwartz kernel theorem, we show that in the
framework of Colombeau generalized functions a large class of linear mappings
admit integral kernels. To do this, we need to introduce news spaces of
generalized functions with slow growth and the corresponding adapted linear
mappings. Finally, we show that in some sense Schwartz' result is contained in
our main theorem.
| [
"math.FA"
] | math.FA | Functional Analysis | 2,549Functional Analysis
|
|
2009.02858 | In the last decade, many semantic-based routing protocols had been designed
for peer-to-peer systems. However, they are not suitable for IoT systems,
mainly due to their high demands in memory and computing power which are not
available in many IoT devices. In this paper, we develop a semantic-based
routing protocol for dynamic IoT systems to facilitate dynamic IoT capability
discovery and composition. Our protocol is a fully decentralized routing
protocol. To reduce the space requirement for routing, each node maintains a
summarized routing table. We design an ontology-based summarization algorithm
to smartly group similar capabilities in the routing tables and support
adaptive routing table compression. We also design an ontology coding scheme to
code keywords used in the routing tables and query messages. To complete the
summarization scheme, we consider the metrics for choosing the summarization
candidates in an overflowing routing table. Some of these metrics are novel and
are difficult to measure, such as coverage and stability. Our solutions
significantly reduce the routing table size, ensuring that the routing table
size can be bounded by the available memory of the IoT devices, while
supporting efficient IoT capability lookup. Experimental results show that our
approach can yield significantly lower network traffic and memory requirement
for IoT capability lookup when compared with existing semantic-based routing
algorithms including a centralized solution, a DHT-based approach, a controlled
flooding scheme, and a cache-based solution.
| [
"cs.NI",
"cs.DC"
] | cs.NI | cs.DC | Networking and Internet Architecture;Distributed, Parallel, and Cluster Computing | 4,727Networking and Internet Architecture;Distributed, Parallel, and Cluster Computing
|
1907.12565 | We perform numerical evolutions of the fully non-linear Einstein-(complex,
massive)Klein-Gordon and Einstein-(complex)Proca systems, to assess the
formation and stability of spinning bosonic stars. In the scalar/vector case
these are known as boson/Proca stars. Firstly, we consider the formation
scenario. Starting with constraint-obeying initial data, describing a dilute,
axisymmetric cloud of spinning scalar/Proca field, gravitational collapse
towards a spinning star occurs, via gravitational cooling. In the scalar case
the formation is transient, even for a non-perturbed initial cloud; a
non-axisymmetric instability always develops ejecting all the angular momentum
from the scalar star. In the Proca case, by contrast, no instability is
observed and the evolutions are compatible with the formation of a spinning
Proca star. Secondly, we address the stability of an existing star, a
stationary solution of the field equations. In the scalar case, a
non-axisymmetric perturbation develops collapsing the star to a spinning black
hole. No such instability is found in the Proca case, where the star survives
large amplitude perturbations; moreover, some excited Proca stars decay to, and
remain as, fundamental states. Our analysis suggests bosonic stars have
different stability properties in the scalar/vector case, which we tentatively
relate to their toroidal/spheroidal morphology. A parallelism with
instabilities of spinning fluid stars is briefly discussed.
| [
"gr-qc",
"astro-ph.HE",
"hep-th"
] | gr-qc | astro-ph.HE | General Relativity and Quantum Cosmology;High Energy Astrophysical Phenomena;High Energy Physics - Theory | 2,734General Relativity and Quantum Cosmology;High Energy Astrophysical Phenomena;High Energy Physics - Theory
|
2401.02580 | We study $\mathfrak{sl}_2$ and $\mathfrak{sl}_3$ global conformal blocks on a
sphere and a torus, using the shadow formalism. These blocks arise in the
context of Virasoro and $\mathcal{W}_3$ conformal field theories in the large
central charge limit. In the $\mathfrak{sl}_2$ case, we demonstrate that the
shadow formalism yields the known expressions in terms of conformal partial
waves. Then, we extend this approach to the $\mathfrak{sl}_3$ case and show
that it allows to build simple integral representations for $\mathfrak{sl}_3$
global blocks. We demonstrate this construction on two examples: the four-point
block on the sphere and the one-point torus block.
| [
"hep-th"
] | hep-th | High Energy Physics - Theory | 3,266High Energy Physics - Theory
|
|
math/0311101 | Asymptotic cones of metric spaces were first invented by Gromov. They are
metric spaces which capture the 'large-scale structure' of the underlying
metric space. Later, van den Dries and Wilkie gave a more general construction
of asymptotic cones using ultrapowers. Certain facts about asymptotic cones,
like the completeness of the metric space, now follow rather easily from
saturation properties of ultrapowers, and in this survey, we want to present
two applications of the van den Dries-Wilkie approach. Using ultrapowers we
obtain an explicit description of the asymptotic cone of a semisimple Lie
group. From this description, using semi-algebraic groups and non-standard
methods, we can give a short proof of the Margulis Conjecture. In a second
application, we use set theory to answer a question of Gromov.
| [
"math.GT",
"math.LO"
] | math.GT | math.LO | Geometric Topology;Logic | 7,267longtail
|
1212.4484 | We perform a global fit of the most relevant neutrinoless double beta decay
experiments within the standard model with massive Majorana neutrinos. Using
Bayesian inference makes it possible to take into account the theoretical
uncertainties on the nuclear matrix elements in a fully consistent way. First,
we analyze the data used to claim the observation of neutrinoless double beta
decay in Ge-76, and find strong evidence (according to Jeffrey's scale) for a
peak in the spectrum and moderate evidence for that the peak is actually close
to the energy expected for the neutrinoless decay. We also find a significantly
larger statistical error than the original analysis, which we include in the
comparison with other data. Then, we statistically test the consistency between
this claim with that of recent measurements using Xe-136. We find that the two
data sets are about 40 to 80 times more probable under the assumption that they
are inconsistent, depending on the nuclear matrix element uncertainties and the
prior on the smallest neutrino mass. Hence, there is moderate to strong
evidence of incompatibility, and for equal prior probabilities the posterior
probability of compatibility is between 1.3% and 2.5%. If one, despite such
evidence for incompatibility, combines the two data sets, we find that the
total evidence of neutrinoless double beta decay is negligible. If one ignores
the claim, there is weak evidence against the existence of the decay. We also
perform approximate frequentist tests of compatibility for fixed ratios of the
nuclear matrix elements, as well as of the no signal hypothesis. Generalization
to other sets of experiments as well as other mechanisms mediating the decay is
possible.
| [
"hep-ph",
"hep-ex",
"nucl-ex",
"nucl-th"
] | hep-ph | hep-ex | High Energy Physics - Phenomenology;High Energy Physics - Experiment;Nuclear Experiment;Nuclear Theory | 3,215High Energy Physics - Phenomenology;High Energy Physics - Experiment;Nuclear Experiment;Nuclear Theory
|
1306.4090 | In this paper, we propose a model for evaluating the transmission performance
of multipath transport. Previous researches focused exclusively on single pair
users in simple scenarios. The distinct perspective in this paper is to build
models for analyzing the performance when multipath transport is used in the
entire network scope. We illustrate the influences on the transmission
performance caused by the variation of network topologies, the services'
arrival rate, the services' size and other parameters. We demonstrate through
simulation that multipath transport could conditionally increase the throughput
than single-path transport. And it has the capability to support higher
services' arrival rate in various network topologies. And higher multi-parent
probability will be beneficial for multipath transport to take its advantages.
| [
"cs.NI"
] | cs.NI | Networking and Internet Architecture | 4,711Networking and Internet Architecture
|
|
1906.04272 | Given the magnitude of online auction transactions, it is difficult to
safeguard consumers from dishonest sellers, such as shill bidders. To date, the
application of Machine Learning Techniques (MLTs) to auction fraud has been
limited, unlike their applications for combatting other types of fraud. Shill
Bidding (SB) is a severe auction fraud, which is driven by modern-day
technologies and clever scammers. The difficulty of identifying the behavior of
sophisticated fraudsters and the unavailability of training datasets hinder the
research on SB detection. In this study, we developed a high-quality SB
dataset. To do so, first, we crawled and preprocessed a large number of
commercial auctions and bidders' history as well. We thoroughly preprocessed
both datasets to make them usable for the computation of the SB metrics.
Nevertheless, this operation requires a deep understanding of the behavior of
auctions and bidders. Second, we introduced two new SB pattern s and
implemented other existing SB patterns. Finally, we removed outliers to improve
the quality of training SB data.
| [
"cs.LG",
"cs.CY"
] | cs.LG | cs.CY | Machine Learning;Computers and Society | 4,070Machine Learning;Computers and Society
|
2012.11129 | The Arnold-Beltrami-Childress (ABC) flow and the Kolmogorov flow are three
dimensional periodic divergence free velocity fields that exhibit chaotic
streamlines. We are interested in front speed enhancement in G-equation of
turbulent combustion by large intensity ABC and Kolmogorov flows. We give a
quantitative construction of the ballistic orbits of ABC and Kolmogorov flows,
namely those with maximal large time asymptotic speeds in a coordinate
direction. Thanks to the optimal control theory of G-equation (a convex but
non-coercive Hamilton-Jacobi equation), the ballistic orbits serve as
admissible trajectories for front speed estimates. To study the tightness of
the estimates, we compute the front speeds of G-equation based on a
semi-Lagrangian (SL) scheme with Strang splitting and weighted essentially
non-oscillatory (WENO) interpolation. Time step size is chosen so that the
Courant number grows sublinearly with the flow intensity. Numerical results
show that the front speed growth rate in terms of the flow intensity may
approach the analytical bounds from the ballistic orbits.
| [
"math.NA",
"cs.NA",
"math.AP"
] | math.NA | cs.NA | Numerical Analysis;Numerical Analysis;Analysis of PDEs | 5,061Numerical Analysis;Numerical Analysis;Analysis of PDEs
|
2103.06904 | Let $h$ be a harmonic function defined on a spherical disk. It is shown that
$\Delta^k |h|^2$ is nonnegative for all $k\in \mathbb{N}$ where $\Delta$ is the
Laplace-Beltrami operator. This fact is generalized to harmonic functions
defined on a disk in a normal homogeneous compact Riemannian manifold, and in
particular in a symmetric space of the compact type. This complements a similar
property for harmonic functions on $\mathbb{R}^n$ discovered by the first two
authors and is related to strong convexity of the $L^2$-growth function of
harmonic functions.
| [
"math.SP",
"math.AP",
"math.DG"
] | math.SP | math.AP | Spectral Theory;Analysis of PDEs;Differential Geometry | 6,783Spectral Theory;Analysis of PDEs;Differential Geometry
|
1004.1019 | In a recent paper [Phys. Rev. B 72, 153314 (2005)], the $k^{3}$-Dresselhaus
term in the contacts and the full form of the current operator are considered
for spin-dependent tunneling through a symmetric barrier. The authors found
that the full form of the current operator has a much larger influence on the
spin polarization than it was initially thought. In this Comment we will show
that their treatment of the other problem, the $k^{3}$-Dresselhaus term in the
contacts, is incorrect. Their proposed solution in the contacts simply does not
obey the Schr\"{o}dinger equation. In this context we also comment on the
definition and the suitability of spin polarization in contacts with spin-orbit
coupling.
| [
"cond-mat.mes-hall"
] | cond-mat.mes-hall | Mesoscale and Nanoscale Physics | 4,450Mesoscale and Nanoscale Physics
|
|
1809.03929 | The reaction between D$^+$ and H$_2$ plays an important role in
astrochemistry at low temperatures and also serves as a prototype for simple
ion-molecule reaction. Its ground $\tilde{X}~^1A^{\prime}$ state has a very
small thermodynamic barrier (up to 1.8$\times 10^{-2}$ eV) and the reaction
proceeds through the formation of an intermediate complex lying within the
potential well of depth of at least 0.2 eV thus representing a challenge for
dynamical studies. In the present work, we analyze the title reaction within
the temperature range of 20 $-$ 100 K by means of ring polymer molecular
dynamics (RPMD) and quasi-classical trajectory (QCT) methods over the
full-dimensional global potential energy surface developed by Aguado et al. [A.
Aguado, O. Roncero, C. Tablero, C. Sanz, and M. Paniagua, J. Chem. Phys., 2000,
112, 1240]. The computed thermal RPMD and QCT rate coefficients are found to be
almost independent of temperature and fall within the range of 1.34 $-$
2.01$\times$10$^{-9}$ cm$^3$ s$^{-1}$. They are also in a very good agreement
with the previous time-independent quantum mechanical and statistical quantum
method calculations. Furthermore, we observe that the choice of asymptotic
separation distance between the reactants can markedly alter the rate
coefficient in the low temperature regime (20 $-$ 50 K). Therefore it is of
utmost importance to correctly assign the value of this parameter for dynamical
studies, particularly at very low temperatures of astrochemical importance. We
finally conclude that experimental rate measurements for the title reaction are
highly desirable in future.
| [
"physics.chem-ph"
] | physics.chem-ph | Chemical Physics | 859Chemical Physics
|
|
hep-ph/9401250 | A model of a light $Z'$ boson is constructed and phenomenological bounds are
derived. This $Z'$ boson arises from a very simple extension to the Standard
Model, and it is constrained to be light because the vacuum expectation values
which generate its mass also break the electroweak gauge group. It is difficult
to detect experimentally because it couples exclusively or primarily (depending
on symmetry breaking details) to second and third generation leptons. However,
if the $Z'$ boson is sufficiently light, then there exists the possibility of
the two-body decay $\tau \rightarrow \mu Z'$ occuring. This will provide a
striking signature to test the model.
| [
"hep-ph"
] | hep-ph | High Energy Physics - Phenomenology | 3,129High Energy Physics - Phenomenology
|
|
1610.03293 | The analysis of the quantum Hall response of a small system of ultracold
bosonic atoms through the variation of its Hall resistivity against the applied
gauge magnetic field, provides a powerful method to unmask its strongly
correlated states in a quite eshaustive way. Within a fixed range of values of
the magnetic field in the lowest Landau-level regime, where the resistivity
displays two successive plateaux, we identify the implied states as the
Pfaffian and the state with filling factor \nu=2/3 in the thermodynamic limit.
We fix the conditions to have good observability.
| [
"cond-mat.quant-gas"
] | cond-mat.quant-gas | Quantum Gases | 5,914Quantum Gases
|
|
2012.02101 | In one-stage or non-adaptive group testing, instead of testing every sample
unit individually, they are split, bundled in pools, and simultaneously tested.
The results are then decoded to infer the states of the individual items. This
combines advantages of adaptive pooled testing, i. e. saving resources and
higher throughput, with those of individual testing, e. g. short detection time
and lean laboratory organisation, and might be suitable for screening during
outbreaks. We study the COMP and NCOMP decoding algorithms for non-adaptive
pooling strategies based on maximally disjunct pooling matrices with constant
row and column sums in the linear prevalence regime and in the presence of
noisy measurements motivated by PCR tests. We calculate sensitivity,
specificity, the probabilities of Type I and II errors, and the expected number
of items with a positive result as well as the expected number of false
positives and false negatives. We further provide estimates on the variance of
the number of positive and false positive results. We conduct a thorough
discussion of the calculations and bounds derived. Altogether, the article
provides blueprints for screening strategies and tools to help decision makers
to appropriately tune them in an outbreak.
| [
"stat.AP",
"cs.DM",
"q-bio.QM"
] | stat.AP | cs.DM | Applications;Discrete Mathematics;Quantitative Methods | 7,267longtail
|
cs/9905013 | Integrating the outputs of multiple classifiers via combiners or
meta-learners has led to substantial improvements in several difficult pattern
recognition problems. In the typical setting investigated till now, each
classifier is trained on data taken or resampled from a common data set, or
(almost) randomly selected subsets thereof, and thus experiences similar
quality of training data. However, in certain situations where data is acquired
and analyzed on-line at several geographically distributed locations, the
quality of data may vary substantially, leading to large discrepancies in
performance of individual classifiers. In this article we introduce and
investigate a family of classifiers based on order statistics, for robust
handling of such cases. Based on a mathematical modeling of how the decision
boundaries are affected by order statistic combiners, we derive expressions for
the reductions in error expected when such combiners are used. We show
analytically that the selection of the median, the maximum and in general, the
$i^{th}$ order statistic improves classification performance. Furthermore, we
introduce the trim and spread combiners, both based on linear combinations of
the ordered classifier outputs, and show that they are quite beneficial in
presence of outliers or uneven classifier performance. Experimental results on
several public domain data sets corroborate these findings.
| [
"cs.LG",
"cs.CV",
"cs.NE"
] | cs.LG | cs.CV | Machine Learning;Computer Vision and Pattern Recognition;Neural and Evolutionary Computing | 4,060Machine Learning;Computer Vision and Pattern Recognition;Neural and Evolutionary Computing
|
2303.18060 | This White Paper sets out to explain the value that metamodelling can bring
to air traffic management (ATM) research. It will define metamodelling and
explore what it can, and cannot, do. The reader is assumed to have basic
knowledge of SESAR: the Single European Sky ATM Research project. An important
element of SESAR, as the technological pillar of the Single European Sky
initiative, is to bring about improvements, as measured through specific key
performance indicators (KPIs), and as implemented by a series of so-called
SESAR 'Solutions'. These 'Solutions' are new or improved operational procedures
or technologies, designed to meet operational and performance improvements
described in the European ATM Master Plan.
| [
"cs.LG",
"cs.AI",
"cs.SY",
"eess.SY"
] | cs.LG | cs.AI | Machine Learning;Artificial Intelligence;Systems and Control;Systems and Control | 3,991Machine Learning;Artificial Intelligence;Systems and Control;Systems and Control
|
2002.12015 | We introduce and study a family of spaces of entire functions in one variable
that generalise the classical Paley-Wiener and Bernstein spaces. Namely, we
consider entire functions of exponential type $a$ whose restriction to the real
line belongs to the homogeneous Sobolev space $\dot{W}^{s,p}$ and we call these
spaces fractional Paley-Wiener if $p=2$ and fractional Bernstein spaces if
$p\in(1,\infty)$, that we denote by $PW^s_a$ and $\mathcal B^{s,p}_a$,
respectively. For these spaces we provide a Paley-Wiener type characterization,
we remark some facts about the sampling problem in the Hilbert setting and
prove generalizations of the classical Bernstein and Plancherel-P\'olya
inequalities. We conclude by discussing a number of open questions.
| [
"math.CV",
"math.FA"
] | math.CV | math.FA | Complex Variables;Functional Analysis | 1,154Complex Variables;Functional Analysis
|
astro-ph/0607372 | We present the adaptive optics assisted, near-infrared VLTI instrument -
GRAVITY - for precision narrow-angle astrometry and interferometric phase
referenced imaging of faint objects. Precision astrometry and phase-referenced
interferometric imaging will realize the most advanced vision of
optical/infrared interferometry with the VLT. Our most ambitious science goal
is to study motions within a few times the event horizon size of the Galactic
Center massive black hole and to test General Relativity in its strong field
limit. We define the science reference cases for GRAVITY and derive the top
level requirements for GRAVITY. The installation of the instrument at the VLTI
is planned for 2012.
| [
"astro-ph"
] | astro-ph | Astrophysics | 463Astrophysics
|
|
2005.08609 | Red-blue pebble games model the computation cost of a two-level memory
hierarchy. We present various hardness results in different red-blue pebbling
variants, with a focus on the oneshot model. We first study the relationship
between previously introduced red-blue pebble models (base, oneshot, nodel). We
also analyze a new variant (compcost) to obtain a more realistic model of
computation. We then prove that red-blue pebbling is NP-hard in all of these
model variants. Furthermore, we show that in the oneshot model, a
$\delta$-approximation algorithm for $\delta<2$ is only possible if the unique
games conjecture is false. Finally, we show that greedy algorithms are not good
candidates for approximation, since they can return significantly worse
solutions than the optimum.
| [
"cs.CC"
] | cs.CC | Computational Complexity | 1,280Computational Complexity
|
|
1106.4010 | We study defects of various dimensions moving through Anti-de Sitter space.
Using the AdS/CFT correspondence this allows us to probe aspects of the dual
quantum field theory. We focus on the energy loss experienced by these defects
as they move through the CFT plasma. We find that the behavior of these
physical quantities is governed by induced world-volume horizons. We identify
world-volume analogs for several gravitational phenomena including black holes,
the Hawking-Page phase transition and expanding cosmological horizons.
| [
"hep-th"
] | hep-th | High Energy Physics - Theory | 3,266High Energy Physics - Theory
|
|
quant-ph/0103016 | The set of all separable quantum states is compact and convex. We focus on
the two-qubit quanum system and study the boundary of the set. Then we give the
criterion to determine whether a separable state is on the boundary. Some
straightforward geometrical interpretations for entanglement are based on the
concept and presented subsequently.
| [
"quant-ph"
] | quant-ph | Quantum Physics | 5,985Quantum Physics
|
|
1110.2177 | We offer predictions of symmetron modified gravity in the neighborhood of
realistic dark matter halos. The predictions for the fifth force are obtained
by solving the nonlinear symmetron equation of motion in the spherical NFW
approximation. In addition, we compare the three major known screening
mechanisms: Vainshtein, Chameleon, and Symmetron around such dark matter
sources, emphasizing the significant differences between them and highlighting
observational tests which exploit these differences. Finally, we demonstrate
the host halo environmental screening effect ("blanket screening") on smaller
satellite halos by solving for the modified forces around a density profile
which is the sum of satellite and approximate host components.
| [
"astro-ph.CO",
"gr-qc"
] | astro-ph.CO | gr-qc | Cosmology and Nongalactic Astrophysics;General Relativity and Quantum Cosmology | 1,745Cosmology and Nongalactic Astrophysics;General Relativity and Quantum Cosmology
|
1507.06294 | Past studies have already shown that stars in open clusters are chemically
homogeneous (e.g. De Silva et al. 2006, 2007 and 2009). These results support
the idea that stars born from the same giant molecular cloud should have the
same chemical composition. In this context, the chemical tagging technique was
proposed by Freeman & Bland-Hawthorn 2002. The principle is to recover
disrupted stellar clusters by looking only to the stellar chemical composition.
In order to evaluate the feasibility of this approach, it is necessary to test
if we can distinguish between stars born from different molecular clouds. For
this purpose, we studied the chemical composition of stars in 32 old and
intermediate-age open clusters, and we applied machine learning algorithms to
recover the original cluster by only considering the chemical signatures.
| [
"astro-ph.SR",
"astro-ph.GA"
] | astro-ph.SR | astro-ph.GA | Solar and Stellar Astrophysics;Astrophysics of Galaxies | 6,669Solar and Stellar Astrophysics;Astrophysics of Galaxies
|
2010.00083 | By employing Pauli measurements, we present some nonlinear steering criteria
applicable for arbitrary two-qubit quantum systems and optimized ones for
symmetric quantum states. These criteria provide sufficient conditions to
witness steering, which can recover the previous elegant results for some
well-known states. Compared with the existing linear steering criterion and
entropic criterion, ours can certify more steerable states without selecting
measurement settings or correlation weights, which can also be used to verify
entanglement as all steerable quantum states are entangled.
| [
"quant-ph"
] | quant-ph | Quantum Physics | 5,985Quantum Physics
|
|
1705.04091 | This text surveys classical and recent results in the field of amenability of
groups, from a combinatorial standpoint. It has served as the support of
courses at the University of G\"ottingen and the \'Ecole Normale Sup\'erieure.
The goals of the text are (1) to be as self-contained as possible, so as to
serve as a good introduction for newcomers to the field; (2) to stress the use
of combinatorial tools, in collaboration with functional analysis, probability
etc., with discrete groups in focus; (3) to consider from the beginning the
more general notion of amenable actions; (4) to describe recent classes of
examples, and in particular groups acting on Cantor sets and topological full
groups.
| [
"math.GR",
"math.FA"
] | math.GR | math.FA | Group Theory;Functional Analysis | 2,946Group Theory;Functional Analysis
|
hep-ex/0406031 | The Standard Model of particle physics contains about two dozen parameters -
such as particle masses - whose origins are still unknown and cannot be
predicted, but whose values are constrained through their interactions. In
particular, the masses of the top (t) quark (M_t) and W boson constrain the
mass of the long-hypothesized, but thus far not observed, Higgs boson. A
precise measurement of the top-quark mass can therefore point to where to look
for the Higgs, and indeed whether the hypothesis of a SM Higgs is consistent
with experimental data. Since top quarks are produced in pairs and decay in
only ~10^-24 s into various final states, reconstructing their mass from their
decay products is very challenging. Here we report a technique that extracts
far more information from each top-quark event and yields a greatly improved
precision on the top mass of 5.3 GeV/c^2, compared to previous measurements.
When our new result is combined with our published measurement in a
complementary decay mode and with the only other measurements available, the
new world average for M_t becomes 178.0 +- 4.3 GeV/c^2. As a result, the most
likely Higgs mass increases from the experimentally excluded value of 96
GeV/c^2 to 117 GeV/c^2, which is beyond current experimental sensitivity. The
upper limit on the Higgs mass at 95% confidence level is raised from 219
GeV/c^2 to 251 GeV/c^2.
| [
"hep-ex",
"hep-ph"
] | hep-ex | hep-ph | High Energy Physics - Experiment;High Energy Physics - Phenomenology | 3,075High Energy Physics - Experiment;High Energy Physics - Phenomenology
|
astro-ph/0511765 | Verification of theoretical predictions of an oscillating behavior of the
fine-structure constant alpha with cosmic time requires high precision Delta
alpha/alpha measurements at individual redshifts, while in earlier studies the
mean Delta alpha/alpha values averaged over wide redshift intervals were
usually reported. This requirement can be met via the single ion differential
alpha measurement (SIDAM) procedure proposed in Levshakov et al. (2005). We
apply the SIDAM to the FeII lines associated with the damped Ly-alpha system
observed at z=1.15 in the spectrum of HE0515-4414. The weighted mean <Delta
alpha/alpha> calculated on base of carefully selected 34 FeII pairs {1608,X} (X
= 2344, 2374, and 2586 A) is <Delta alpha/alpha> = (-0.07+/-0.84) 10^{-6}
(1sigma C.L.). The precision of this estimate improves by a factor 2 the
previous one reported for the same system by Quast et al. (2004). The obtained
result represents an absolute improvement with respect to what has been done in
the measurements of Delta alpha/alpha.
| [
"astro-ph"
] | astro-ph | Astrophysics | 463Astrophysics
|
|
1410.3559 | A sufficient condition for $\bar{\partial}$ to have closed range is given for
pseudoconvex, possibly unbounded domains in $\mathbb{C}^n$.
| [
"math.CV"
] | math.CV | Complex Variables | 1,135Complex Variables
|
|
1709.00519 | We study birational geometry of the moduli space of parabolic bundles over a
projective line, in the framework of Mori's program. We show that the moduli
space is a Mori dream space. As a consequence, we obtain the finite generation
of the algebra of type A conformal blocks. Furthermore, we compute the
H-representation of the effective cone which was previously obtained by
Belkale. For each big divisor, the associated birational model is described in
terms of moduli space of parabolic bundles.
| [
"math.AG",
"math.QA",
"math.RT"
] | math.AG | math.QA | Algebraic Geometry;Quantum Algebra;Representation Theory | 146Algebraic Geometry;Quantum Algebra;Representation Theory
|
hep-th/0112012 | Quantum non-perturbative geometry of the universal hypermultiplet is
investigated. We consider the simple case when the D-instantons, originating
from the Calabi-Yau wrapped D2-branes, preserve a U(1)xU(1) symmetry of the
universal hypermultiplet moduli space. The cluster decomposition of
D-instantons is proved to be valid in a curved spacetime. We find an SL(2,Z)
duality-invariant quaternionic solution to the effective NLSM metric of the
universal hypermultiplet, which is governed by a modular-invariant function.
This function appears to be the same function found by Green and Gutperle, and
describing the modular invariant completion of the R^4 term by the D-instanton
effects in the type-II superstring/M-theory. We argue that our solution
interpolates between the perturbative (large CY volume) region and the
superconformal (Landau-Ginzburg) region in the universal hypermultiplet moduli
space. We also calculate a non-perturbative scalar potential in the
hyper-K\"ahler limit, when an abelian isometry of the universal hypermultiplet
moduli space is gauged in the presence of D-instantons.
| [
"hep-th"
] | hep-th | High Energy Physics - Theory | 3,266High Energy Physics - Theory
|
|
1908.01025 | By analyzing Fe-Ni-B compositional diagram we predict an energetically and
dynamically stable FeNiB2 compound. This system belongs to the class of highly
responsive state of material, as it is very sensitive to the external
perturbations. This state is also characterized by a high level of spin
fluctuations which strongly influence possible magnetic long- and short-range
orders. Furthermore, we demonstrate that these antiferromagnetically dominating
fluctuations could lead to the appearance of spin mediated superconductivity.
The obtained results suggest a promising avenue for the search of strong spin
fluctuation systems and related superconductors.
| [
"cond-mat.mtrl-sci"
] | cond-mat.mtrl-sci | Materials Science | 4,287Materials Science
|
|
1702.05114 | Sand fences are widely applied to prevent soil erosion by wind in areas
affected by desertification. Sand fences also provide a way to reduce the
emission rate of dust particles, which is triggered mainly by the impacts of
wind-blown sand grains onto the soil and affects the Earth's climate. Many
different types of fence have been designed and their effects on the sediment
transport dynamics studied since many years. However, the search for the
optimal array of fences has remained largely an empirical task. In order to
achieve maximal soil protection using the minimal amount of fence material, a
quantitative understanding of the flow profile over the relief encompassing the
area to be protected including all employed fences is required. Here we use
Computational Fluid Dynamics to calculate the average turbulent airflow through
an array of fences as a function of the porosity, spacing and height of the
fences. Specifically, we investigate the factors controlling the fraction of
soil area over which the basal average wind shear velocity drops below the
threshold for sand transport when the fences are applied. We introduce a cost
function, given by the amount of material necessary to construct the fences. We
find that, for typical sand-moving wind velocities, the optimal fence height
(which minimizes this cost function) is around $50\,$cm, while using fences of
height around $1.25\,$m leads to maximal cost.
| [
"physics.comp-ph",
"physics.flu-dyn"
] | physics.comp-ph | physics.flu-dyn | Computational Physics;Fluid Dynamics | 1,400Computational Physics;Fluid Dynamics
|
2109.04090 | One can derive a large class of new $\mathcal{N}=1$ SCFTs by turning on
$\mathcal{N}=1$ preserving deformations for $\mathcal{N}=2$ Argyres-Dougals
theories. In this work, we use $\mathcal{N}=2$ superconformal indices to get
indices of $\mathcal{N}=1$ SCFTs, then use these indices to derive chiral rings
of $\mathcal{N}=1$ SCFTs. For a large class of $\mathcal{N}=2$ theories, we
find that the IR theory contains only free chirals if we deform the parent
$\mathcal{N}=2$ theory using the Coulomb branch operator with smallest scaling
dimension. Our results provide interesting lessons on studies of
$\mathcal{N}=1$ theories, such as $a$-maximization, accidental symmetries,
chiral ring, etc.
| [
"hep-th"
] | hep-th | High Energy Physics - Theory | 3,266High Energy Physics - Theory
|
|
hep-lat/9607005 | We study the interface between two different Z(3) vacua in the deconfined
phase of SU(3) pure gauge theory in 2+1 dimensions just above the critical
temperature. In simulations of the Euclidean lattice gauge theory formulation
of the system we measure the fluctuations of the interface as the critical
temperature is approached and as a function of system size. We show that the
intrinsic width of the interface remains small even very close to the critical
temperature. Some dynamical exponents which govern the interaction of the
interface with our Monte Carlo algorithm are also estimated. We conclude that
the Z(3) interface has properties broadly similar to those in many other
comparable statistical mechanical systems.
| [
"hep-lat"
] | hep-lat | High Energy Physics - Lattice | 3,092High Energy Physics - Lattice
|
|
2110.12740 | In light of the LHCb observations about the $B_s \to D_s^{(*)}\ell \nu_\ell$
semileptonic decays, we study these channels within the Standard Model
framework of covariant confined quark model. The necessary transition form
factors are computed in the entire dynamical range of momentum transfer squared
with built-in infrared confinement. Our computed ratios of the decay widths
from tau mode to muon mode for $D_s$ and $D_s^*$ mesons are found to be $R(D_s)
= 0.271 \pm 0.069$ and $R(D_s^*) = 0.240 \pm 0.038$. We further determine the
ratio of the decay width from $D_s$ and $D_s^*$ channel for muon mode
$\Gamma(B_s \to D_s \mu^+ \nu_\mu)/\Gamma(B_s \to D_s^* \mu^+ \nu_\mu) = 0.451
\pm 0.093$. Our results are in excellent agreement with the data from the
latest LHCb experiments as well as lattice quantum chromodynamics simulations.
We also compare the shape of differential decay distribution for $B_s \to D_s^*
\mu^+ \nu_\mu$ with the LHCb data and our results are in very good agreement
throughout all the individual bins. Some other physical observables such as
forward-backward asymmetry and longitudinal polarizations of leptons in the
final state are also computed.
| [
"hep-ph"
] | hep-ph | High Energy Physics - Phenomenology | 3,129High Energy Physics - Phenomenology
|
|
2108.01531 | Quantum computation based on geometric phase is generally believed to be more
robust against certain errors or noises than the conventional dynamical
strategy. However, the gate error caused by the decoherence effect is
inevitable, and thus faster gate operations are highly desired. Here, we
propose a nonadiabatic holonomic quantum computation (NHQC) scheme with detuned
interactions on $\Delta$-type three-level system, which combines the
time-optimal control technique with the time-independent detuning adjustment to
further accelerate universal gate operations, {so that the gate-time can be
greatly shortened within the hardware limitation}, and thus high-fidelity gates
can be obtained. Meanwhile, our numerical simulations show that the gate
robustness is also stronger than previous schemes. Finally, we present an
implementation of our proposal on superconducting quantum circuits, with a
decoherence-free subspace encoding, based on the experimentally demonstrated
parametrically tunable coupling technique, which simplifies previous
investigations. Therefore, our protocol provides a more promising alternative
for future fault-tolerant quantum computation.
| [
"quant-ph"
] | quant-ph | Quantum Physics | 5,985Quantum Physics
|