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arxiv_dataset-55001408.4694 | Parity violating asymmetry with nuclear medium effects in deep inelastic
$\vec e$ scattering
nucl-th
Recently at JLab using polarised electron beam on unpolarised deuteron target
measurements have been performed for the parity violating asymmetry($A_{PV}$)
and there are future plans to measure this asymmetry using various nuclear
targets. In this paper, we study $A_{PV}$ in nuclear targets like $^{12}C$,
$^{56}Fe$ and $^{208}Pb$, in a local density approximation using spectral
function which takes into account Fermi motion, binding energy correction and
nucleon correlations. Furthermore, the pion and rho cloud contributions have
also been taken into account. The present model has been used earlier to study
medium effects in electromagnetic as well as weak interaction induced processes
in the DIS region.
| arxiv topic:nucl-th |
arxiv_dataset-55011408.4794 | On a nonlinear model for tumor growth with drug application
math.AP
We investigate the dynamics of a nonlinear system modeling tumor growth with
drug application. The tumor is viewed as a mixture consisting of proliferating,
quiescent and dead cells as well as a nutrient in the presence of a drug. The
system is given by a multi-phase flow model: the densities of the different
cells are governed by a set of transport equations, the density of the nutrient
and the density of the drug are governed by rather general diffusion equations,
while the velocity of the tumor is given by Brinkman's equation. The domain
occupied by the tumor in this setting is a growing continuum $\Omega$ with
boundary $\partial \Omega$ both of which evolve in time. Global-in-time weak
solutions are obtained using an approach based on penalization of the boundary
behavior, diffusion and viscosity in the weak formulation. Both the solutions
and the domain are rather general, no symmetry assumption is required and the
result holds for large initial data. This article is part of a research program
whose aim is the investigation of the effect of drug application in tumor
growth.
| arxiv topic:math.AP |
arxiv_dataset-55021408.4894 | Flow Curvature Method applied to Canard Explosion
math.DS
The aim of this work is to establish that the bifurcation parameter value
leading to a canard explosion in dimension two obtained by the so-called
Geometric Singular Perturbation Method can be found according to the Flow
Curvature Method. This result will be then exemplified with the classical Van
der Pol oscillator.
| arxiv topic:math.DS |
arxiv_dataset-55031408.4994 | Interference Alignment for Multicell Multiuser MIMO Uplink Channels
cs.IT math.IT
This paper proposes a linear interference alignment (IA) scheme which can be
used for uplink channels in a general multicell multiuser MIMO cellular
network. The proposed scheme aims to align interference caused by signals from
a set of transmitters into a subspace which is established by the signals from
only a subset of those transmitters, thereby effectively reducing the number of
interfering transmitters. The total degrees of freedom (DoF) achievable by the
proposed scheme is given in closed-form expression, and a numerical analysis
shows that the proposed scheme can achieve the optimal DoF in certain scenarios
and provides a higher total DoF than other related schemes in most cases.
| arxiv topic:cs.IT math.IT |
arxiv_dataset-55041408.5094 | Verifiable UML Artifact-Centric Business Process Models (Extended
Version)
cs.DB cs.SE
Artifact-centric business process models have gained increasing momentum
recently due to their ability to combine structural (i.e., data related) with
dynamical (i.e., process related) aspects. In particular, two main lines of
research have been pursued so far: one tailored to business artefact modeling
languages and methodologies, the other focused on the foundations for their
formal verification. In this paper, we merge these two lines of research, by
showing how recent theoretical decidability results for verification can be
fruitfully transferred to a concrete UML-based modeling methodology. In
particular, we identify additional steps in the methodology that, in
significant cases, guarantee the possibility of verifying the resulting models
against rich first-order temporal properties. Notably, our results can be
seamlessly transferred to different languages for the specification of the
artifact lifecycles.
| arxiv topic:cs.DB cs.SE |
arxiv_dataset-55051408.5194 | Reconstructing function fields from rational quotients of mod-$\ell$
Galois groups
math.AG math.KT
In this paper, we develop the main step in the global theory for the
mod-$\ell$ analogue of Bogomolov's program in birational anabelian geometry for
higher-dimensional function fields over algebraically closed fields. More
precisely, we show how to reconstruct a function field $K$ of transcendence
degree $\geq 5$ over an algebraically closed field, up-to inseparable
extensions, from the mod-$\ell$ abelian-by-central Galois group of $K$ endowed
with the collection of mod-$\ell$ rational quotients.
| arxiv topic:math.AG math.KT |
arxiv_dataset-55061408.5294 | Distributed Time-Varying Stochastic Optimization and Utility-Based
Communication
math.OC cs.IT math.IT
We devise a distributed asynchronous stochastic epsilon-gradient-based
algorithm to enable a network of computing and communicating nodes to solve a
constrained discrete-time time-varying stochastic convex optimization problem.
Each node updates its own decision variable only once every discrete time step.
Under some assumptions (among which, strong convexity, Lipschitz continuity of
the gradient, persistent excitation), we prove the algorithm's asymptotic
convergence in expectation to an error bound whose size is related to the
constant stepsize choice alpha, the variability in time of the optimization
problem, and to the accuracy epsilon. Moreover, the convergence rate is linear.
Then, we show how to compute locally stochastic epsilon-gradients that depend
also on the time-varying noise probability density function (PDF) of the
neighboring nodes, without requiring the neighbors to send such PDFs at each
time step. We devise utility-based policies to allow each node to decide
whether to send or not the most up-to-date PDF, which guarantee a given
user-specified error level epsilon in the computation of the stochastic
epsilon-gradient. Numerical simulations display the added value of the proposed
approach and its relevance for estimation and control of time-varying processes
and networked systems.
| arxiv topic:math.OC cs.IT math.IT |
arxiv_dataset-55071408.5394 | Metaplectic Demazure operators and Whittaker functions
math.RT math.NT
In a previous paper the first two named authors defined an action of a Weyl
group on rational functions and used it to construct multiple Dirichlet series.
These series are related to Whittaker functions on an n-fold metaplectic cover
of a reductive group. In this paper, we define metaplectic analogues of the
Demazure and Demazure-Lusztig operators. We show how these operators, together
with results of McNamara, can be used to compute Whittaker functions on
metaplectic groups over p-adic fields.
| arxiv topic:math.RT math.NT |
arxiv_dataset-55081408.5494 | Biharmonic submanifolds in a Riemannian manifold
math.DG
In this paper, we solve affirmatively B.-Y. Chen's conjecture for
hypersurfaces in the Euclidean space, under a generic condition. More
precisely, every biharmonic hypersurface of the Euclidean space must be minimal
if their principal curvatures are simple, and the associated frame field is
irreducible.
| arxiv topic:math.DG |
arxiv_dataset-55091408.5594 | Geodesic Transport Barriers in Jupiter's Atmosphere: A Video-Based
Analysis
nlin.CD
Jupiter's zonal jets and Great Red Spot are well known from still images. Yet
the planet's atmosphere is highly unsteady, which suggests that the actual
material transport barriers delineating its main features should be
time-dependent. Rare video footages of Jupiter's clouds provide an opportunity
to verify this expectation from optically reconstructed velocity fields.
Available videos, however, provide short-time and temporally aperiodic velocity
fields that defy classical dynamical systems analyses focused on asymptotic
features. To this end, we use here the recent theory of geodesic transport
barriers to uncover finite-time mixing barriers in the wind field extracted
from a video captured by NASA's Cassini space mission. More broadly, the
approach described here provides a systematic and frame-invariant way to
extract dynamic coherent structures from time-resolved remote observations of
unsteady continua.
| arxiv topic:nlin.CD |
arxiv_dataset-55101408.5694 | A systematic study of magnetic field in Relativistic Heavy-ion
Collisions in the RHIC and LHC energy regions
hep-ph nucl-th
The features of magnetic field in relativistic heavy-ion collisions are
systematically studied by using a modified magnetic field model in this paper.
The features of magnetic field distributions in the central point are studied
in the RHIC and LHC energy regions. We also predict the feature of magnetic
fields at LHC $\sqrt{s_{NN}}$= 900, 2760 and 7000 GeV based on the detailed
study at RHIC $\sqrt{s_{NN}}$ = 62.4, 130 and 200 GeV. The dependencies of the
features of magnetic fields on the collision energies, centralities and
collision time are systematically investigated, respectively.
| arxiv topic:hep-ph nucl-th |
arxiv_dataset-55111408.5794 | Decoupling, exponential sums and the Riemann zeta function
math.NT
We establish a new decoupling inequality for curves in the spirit of [B-D1],
[B-D2] which implies a new mean value theorem for certain exponential sums
crucial to the Bombieri-Iwaniec method as developed further in [H]. In
particular, this leads to an improved bound $|\zeta(\frac 12+it)|\ll
t^{53/342+\varepsilon}$ for the zeta function on the critical line
| arxiv topic:math.NT |
arxiv_dataset-55121408.5894 | Location Estimation Using Crowdsourced Geospatial Narratives
cs.DB
The "crowd" has become a very important geospatial data provider. Subsumed
under the term Volunteered Geographic Information (VGI), non-expert users have
been providing a wealth of quantitative geospatial data online. With spatial
reasoning being a basic form of human cognition, narratives expressing
geospatial experiences, e.g., travel blogs, would provide an even bigger source
of geospatial data. Textual narratives typically contain qualitative data in
the form of objects and spatial relationships. The scope of this work is (i) to
extract these relationships from user-generated texts, (ii) to quantify them
and (iii) to reason about object locations based only on this qualitative data.
We use information extraction methods to identify toponyms and spatial
relationships and to formulate a quantitative approach based on distance and
orientation features to represent the latter. Positional probability
distributions for spatial relationships are determined by means of a greedy
Expectation Maximization-based (EM) algorithm. These estimates are then used to
"triangulate" the positions of unknown object locations. Experiments using a
text corpus harvested from travel blog sites establish the considerable
location estimation accuracy of the proposed approach.
| arxiv topic:cs.DB |
arxiv_dataset-55131408.5994 | Attenuation of excitation decay rate due to collective effect
quant-ph
We study a series of $N$ oscillators each coupled to its nearest neighbours,
and linearly to a phonon field through the oscillator's number operator. We
show that the Hamiltonian of a pair of adjacent oscillators, or a dimer, within
the series of oscillators can be transformed to a form in which they are
collectively coupled to the phonon field as a composite unit. In the weak
coupling and rotating-wave approximation, the system behaves effectively like
the trilinear boson model in the one excitation subspace of the dimer
subsystem. The reduced dynamics of the one excitation subspace of the dimer
subsystem coupled weakly to a phonon bath is similar to that of a two-level
system, with a metastable state against the vacuum. The decay constant of the
subsystem is proportional to the dephasing rate of the individual oscillator in
a phonon bath, attenuated by a factor that depends on site asymmetry, intersite
coupling and the resonance frequency between the transformed oscillator modes,
or excitons. As a result of the collective effect, the excitation relaxation
lifetime is prolonged over the dephasing lifetime of an individual oscillator
coupled to the same bath.
| arxiv topic:quant-ph |
arxiv_dataset-55141408.6094 | Forming the cores of giant planets from the radial pebble flux in
protoplanetary discs
astro-ph.EP
The formation of planetary cores must proceed rapidly in order for the giant
planets to accrete their gaseous envelopes before the dissipation of the
protoplanetary gas disc (<3 Myr). In orbits beyond 10 AU, direct accumulation
of planetesimals by the cores is too slow. Fragments of planetesimals could be
accreted faster, but planetesimals are likely too large for fragmentation to be
efficient, and resonant trapping poses a further hurdle. Here we instead
investigate the accretion of small pebbles (mm-cm sizes) that are the natural
outcome of an equilibrium between the growth and radial drift of particles. We
construct a simplified analytical model of dust coagulation and pebble drift in
the outer disc, between 5 AU and 100 AU, which gives the temporal evolution of
the solid surface density and the dominant particle size. These two key
quantities determine how core growth proceeds at various orbital distances. We
find that pebble surface densities are sufficiently high to achieve the
inside-out formation of planetary cores within the disc lifetime. The overall
efficiency by which dust gets converted to planets can be high, close to 50 %
for planetary architectures similar to the Solar System. Growth by pebble
accretion in the outer disc is sufficiently fast to overcome catastrophic Type
I migration of the cores. These results require protoplanetary discs with large
radial extent (~100 AU) and assume a low number of initial seed embryos. Our
findings imply that protoplanetary discs with low disc masses, as expected
around low-mass stars (<1 M_sun), or with sub-solar dust-to-gas ratios, do not
easily form gas-giant planets (M > 100 M_E), but preferentially form
Neptune-mass planets or smaller (< 10 M_E). This is consistent with exoplanet
surveys which show that gas giants are relatively uncommon around stars of low
mass or low metallicity.
| arxiv topic:astro-ph.EP |
arxiv_dataset-55151408.6194 | Estereoscopio de Wheatstone 'Revival'
physics.ed-ph
We describe the making of a two-mirrors stereoscope, identical to the first
historical one, with the advantage of employing digital images on LCD monitors.
We surprised the public with it, because they do not imagine being possible to
watch 3D without needing goggless, neither the lack of knowledge of something
so simple and old. Nowadays it is common to have two monitors at the exit of a
computer, so that the system is still a simple one.
| arxiv topic:physics.ed-ph |
arxiv_dataset-55161408.6294 | Tunable Band gap of Iron-Doped Lanthanum-Modified Bismuth Titanate
Synthesized by the Thermal Decomposition of a Secondary Phase
cond-mat.mtrl-sci
The photoelectric properties of complex oxides have prompted interest in
materials with a tunable band gap, because the absorption The substitution of
iron atoms in La-modified bismuth titanate (BLT) can lead to dramatic
improvements in the band gap, however, the substitution of iron atoms in BLT
without forming a BiFeO3 secondary phase is quite challenging. Therefore, a
series of Fe-doped BLT (Fe-BLT) samples were characterized using a solid
reaction at various calcination temperatures (300~900{\deg}C) to remove the
secondary phase. The structural and optical properties were analyzed by X-ray
diffraction and ultraviolet-visible absorption spectroscopy. This paper reports
a new route to synthesize a pure Fe-BLT phase with a reduced optical band gap
by high temperature calcination due to the thermal decomposition of BiFeO3
during high temperature calcination. This simple route to reduce the second
phase can be adapted to other complex oxides for use in emerging oxide
optoelectronic devices.
| arxiv topic:cond-mat.mtrl-sci |
arxiv_dataset-55171408.6394 | A simple characterization of chaos for weighted composition
$C_0$-semigroups on Lebesgue and Sobolev spaces
math.FA
We give a simple characterization of chaos for weighted composition
$C_0$-semigroups on $L^p_\rho(\Omega)$ for an open interval
$\Omega\subseteq\mathbb{R}$. Moreover, we characterize chaos for these classes
of $C_0$-semigroups on the closed subspace $W^{1,p}_*(\Omega)$ of the Sobolev
space $W^{1,p}(\Omega)$ for a bounded interval $\Omega\subset\mathbb{R}$. These
characterizations simplify previously obtained characterization of chaos for
these classes of $C_0$-semigroups.
| arxiv topic:math.FA |
arxiv_dataset-55181408.6494 | On vector-valued Poincar\'e series of weight 2
math.CV math.NT
Given a pair $(\Gamma,\rho)$ of a Fuchsian group of the first kind, and a
unitary representation $\rho$ of $\Gamma$ of arbitrary rank, the problem of
construction of vector-valued Poincar\'e series of weight 2 is considered.
Implications in the theory of parabolic bundles are discussed. When the genus
of the group is zero, it is shown how an explicit basis for the space of these
functions can be constructed.
| arxiv topic:math.CV math.NT |
arxiv_dataset-55191408.6594 | Emission mechanism of GeV-quiet soft gamma-ray pulsars; A case for
peculiar geometry?
astro-ph.HE
There is a growing new class of young spin-down powered pulsars called
GeV-quiet soft gamma-ray pulsar; (1) spectral turnover appears around~10MeV,
(2) the X-ray spectra of below 20 keV can be described by power law with photon
index around 1.2 and (3) the light curve in X-ray/soft gamma-ray bands shows
single broad pulse. Their emission properties are distinct from the normal
gamma-ray pulsars, for which the spectral peak in $\nu F_{\nu}$ appears in GeV
energy bands and the X-ray/gamma-ray light curves show sharp and double (or
more) peaks. In this paper, we discuss that X-ray/soft gamma-ray emissions of
the GeV-quiet soft gamma-ray pulsars are caused bythe synchrotron radiation of
the electron/positron pairs, which are created by the magnetic pair-creation
process near the stellar surface. In our model, the viewing geometry is crucial
factor to discriminate between the normal gamma-ray pulsars and soft gamma-ray
pulsars. Our model suggests that the difference between the magnetic
inclination angle ($\alpha$) and the Earth viewing angle ($\beta$) of the soft
gamma-ray pulsars is small, so that the synchrotron emissions from the high
magnetic field region around the polar cap region dominates in the observed
emissions. Furthermore, the inclination angle of the soft gamma-ray pulsar is
relatively small, $\alpha\leq 30$~degree, and our line of sight is out of the
gamma-ray beam emitted via the curvature radiation process in the outer gap. We
also analysis the six year $Fermi$ data for four soft gamma-ray pulsars to
determine the upper limit of the GeV flux.
| arxiv topic:astro-ph.HE |
arxiv_dataset-55201408.6694 | Sampling through time and phylodynamic inference with coalescent and
birth-death models
q-bio.PE
Many population genetic models have been developed for the purpose of
inferring population size and growth rates from random samples of genetic data.
We examine two popular approaches to this problem, the coalescent and the
birth-death-sampling model, in the context of estimating population size and
birth rates in a population growing exponentially according to the birth-death
branching process. For sequences sampled at a single time, we found the
coalescent and the birth-death-sampling model gave virtually indistinguishable
results in terms of the growth rates and fraction of the population sampled,
even when sampling from a small population. For sequences sampled at multiple
time points, we find that the birth-death model estimators are subject to large
bias if the sampling process is misspecified. Since birth-death-sampling models
incorporate a model of the sampling process, we show how much of the
statistical power of birth-death-sampling models arises from the sequence of
sample times and not from the genealogical tree. This motivates the development
of a new coalescent estimator, which is augmented with a model of the known
sampling process and is potentially more precise than the coalescent that does
not use sample time information.
| arxiv topic:q-bio.PE |
arxiv_dataset-55211408.6794 | The family Floer functor is faithful
math.SG math.AG
Family Floer theory yields a functor from the Fukaya category of a symplectic
manifold admitting a Lagrangian torus fibration to a (twisted) category of
perfect complexes on the mirror rigid analytic space. This functor is shown to
be faithful by a degeneration argument involving moduli spaces of annuli.
| arxiv topic:math.SG math.AG |
arxiv_dataset-55221408.6894 | Correlation Detection and an Operational Interpretation of the Renyi
Mutual Information
quant-ph cs.IT math-ph math.IT math.MP
A variety of new measures of quantum Renyi mutual information and quantum
Renyi conditional entropy have recently been proposed, and some of their
mathematical properties explored. Here, we show that the Renyi mutual
information attains operational meaning in the context of composite hypothesis
testing, when the null hypothesis is a fixed bipartite state and the alternate
hypothesis consists of all product states that share one marginal with the null
hypothesis. This hypothesis testing problem occurs naturally in channel coding,
where it corresponds to testing whether a state is the output of a given
quantum channel or of a 'useless' channel whose output is decoupled from the
environment. Similarly, we establish an operational interpretation of Renyi
conditional entropy by choosing an alternative hypothesis that consists of
product states that are maximally mixed on one system. Specialized to classical
probability distributions, our results also establish an operational
interpretation of Renyi mutual information and Renyi conditional entropy.
| arxiv topic:quant-ph cs.IT math-ph math.IT math.MP |
arxiv_dataset-55231408.6994 | Complex mass definition and the concept of continuous mass
hep-ph
Propagators of unstable particles are considered in the spectral
representation which naturally follows from the concept of continuous mass. The
spectral functions are found with the help of the most general formal and
physical assumptions. Dressed propagators of unstable scalar, vector, and
spinor fields are derived in an analytical way for a variant of parameter
space.
The structure of the propagators is in a correspondence with the complex mass
scheme.
| arxiv topic:hep-ph |
arxiv_dataset-55241408.7094 | Improving the Effectiveness of Content Popularity Prediction Methods
using Time Series Trends
cs.SI physics.soc-ph
We here present a simple and effective model to predict the popularity of web
content. Our solution, which is the winner of two of the three tasks of the
ECML/PKDD 2014 Predictive Analytics Challenge, aims at predicting user
engagement metrics, such as number of visits and social network engagement,
that a web page will achieve 48 hours after its upload, using only information
available in the first hour after upload. Our model is based on two steps. We
first use time series clustering techniques to extract common temporal trends
of content popularity. Next, we use linear regression models, exploiting as
predictors both content features (e.g., numbers of visits and mentions on
online social networks) and metrics that capture the distance between the
popularity time series to the trends extracted in the first step. We discuss
why this model is effective and show its gains over state of the art
alternatives.
| arxiv topic:cs.SI physics.soc-ph |
arxiv_dataset-55251409.0075 | $L$-space surgeries on links
math.GT
An $L$-space link is a link in $S^3$ on which all large surgeries are
$L$-spaces. In this paper, we initiate a general study of the definitions,
properties, and examples of $L$-space links. In particular, we find many
hyperbolic $L$-space links, including some chain links and two-bridge links;
from them, we obtain many hyperbolic $L$-spaces by integral surgeries,
including the Weeks manifold. We give bounds on the ranks of the link Floer
homology of $L$-space links and on the coefficients in the multi-variable
Alexander polynomials. We also describe the Floer homology of surgeries on any
$L$-space link using the link surgery formula of Ozsv\'{a}th and Manolescu. As
applications, we compute the graded Heegaard Floer homology of surgeries on
2-component $L$-space links in terms of only the Alexander polynomial and the
surgery framing, and give a fast algorithm to classify $L$-space surgeries
among them.
| arxiv topic:math.GT |
arxiv_dataset-55261409.0175 | Study of formality for the Heisenberg algebra
math.QA
In this paper, we compute the Chevalley-Eilenberg cohomology of the
three-dimensionnal Heisenberg Lie algebra with values in its universal
enveloping algebra. We also compte the Schouten brackets on cochains and
cohomology level in order to write the formality equations. It turns out that
there is no formality, ans that the perturbed L-infinity structure on the
cohomology has non-trivial terms in infinitely manu degrees.
| arxiv topic:math.QA |
arxiv_dataset-55271409.0275 | Asymptotic pairs, stable sets and chaos in positive entropy systems
math.DS math.FA
We consider positive entropy $G$-systems for certain countable, discrete,
infinite left-orderable amenable groups $G$. By undertaking local analysis, the
existence of asymptotic pairs and chaotic sets will be studied in connecting
with the stable sets. Examples are given for the case of integer lattice
groups, the Heisenberg group, and the groups of integral unipotent upper
triangular matrices.
| arxiv topic:math.DS math.FA |
arxiv_dataset-55281409.0375 | Polynomial solvability of $NP$-complete problems
cs.CC
${ NP}$-complete problem "Hamiltonian cycle"\ for graph $G=(V,E)$ is extended
to the "Hamiltonian Complement of the Graph"\ problem of finding the minimal
cardinality set $H$ containing additional edges so that graph $G=(V,E\cup H)$
is Hamiltonian. The solving of "Hamiltonian Complement of a Graph"\ problem is
reduced to the linear programming problem {\bf P}, which has an optimal integer
solution. The optimal integer solution of {\bf P} is found for any its optimal
solution by solving the linear assignment problem {\bf L}. The existence of
polynomial algorithms for problems {\bf P} and {\bf L} proves the polynomial
solvability of ${ NP}$-complete problems.
| arxiv topic:cs.CC |
arxiv_dataset-55291409.0475 | New Minkowski type inequalities and entropic inequalities for quantum
states of qudits
quant-ph
The two-parameter Minkowski like inequality written for composite quantum
system state is obtained for arbitrary Hermitian nonnegative matrix with trace
equal to unity. The inequality can be used as entropic and information
inequality for density matrix of noncomposite finite quantum system, e.g., for
a single qudit state. The analogs of strong subadditivity condition for the
single qudit is discussed in context of obtained Minkowski like inequality.
| arxiv topic:quant-ph |
arxiv_dataset-55301409.0575 | ImageNet Large Scale Visual Recognition Challenge
cs.CV
The ImageNet Large Scale Visual Recognition Challenge is a benchmark in
object category classification and detection on hundreds of object categories
and millions of images. The challenge has been run annually from 2010 to
present, attracting participation from more than fifty institutions.
This paper describes the creation of this benchmark dataset and the advances
in object recognition that have been possible as a result. We discuss the
challenges of collecting large-scale ground truth annotation, highlight key
breakthroughs in categorical object recognition, provide a detailed analysis of
the current state of the field of large-scale image classification and object
detection, and compare the state-of-the-art computer vision accuracy with human
accuracy. We conclude with lessons learned in the five years of the challenge,
and propose future directions and improvements.
| arxiv topic:cs.CV |
arxiv_dataset-55311409.0675 | Affine differential geometry and smoothness maximization as tools for
identifying geometric movement primitives
q-bio.NC math.DG
Neuroscientific studies of drawing-like movements usually analyze neural
representation of either geometric (eg. direction, shape) or temporal (eg.
speed) features of trajectories rather than trajectory's representation as a
whole. This work is about empirically supported mathematical ideas behind
splitting and merging geometric and temporal features which characterize
biological movements. Movement primitives supposedly facilitate the efficiency
of movements' representation in the brain and comply with different criteria
for biological movements, among them kinematic smoothness and geometric
constraint. Criterion for trajectories' maximal smoothness of arbitrary order
$n$ is employed, $n = 3$ is the case of the minimum-jerk model. I derive a
class of differential equations obeyed by movement paths for which $n$-th order
maximally smooth trajectories have constant rate of accumulating geometric
measurement along the drawn path. Constant rate of accumulating equi-affine arc
corresponds to compliance with the two-thirds power-law model. Geometric
measurement is invariant under a class of geometric transformations and may be
chosen to be an arc in certain geometry. Equations' solutions presumably serve
as candidates for geometric movement primitives. The derived class of
differential equations consists of two parts. The first part is identical for
all geometric parameterizations of the path. The second part enforces
consistency with desired (geometric) parametrization of curves on solutions of
the first part. Equations in different geometries in plane and in space and
their known solutions are presented. Connection between geometric invariance,
motion smoothness, compositionality and performance of the compromised motor
control system is discussed. The derived class of differential equations is a
novel tool for discovering candidates for geometric movement primitives.
| arxiv topic:q-bio.NC math.DG |
arxiv_dataset-55321409.0775 | Feature selection in detection of adverse drug reactions from the Health
Improvement Network (THIN) database
cs.LG cs.CE
Adverse drug reaction (ADR) is widely concerned for public health issue. ADRs
are one of most common causes to withdraw some drugs from market. Prescription
event monitoring (PEM) is an important approach to detect the adverse drug
reactions. The main problem to deal with this method is how to automatically
extract the medical events or side effects from high-throughput medical events,
which are collected from day to day clinical practice. In this study we propose
a novel concept of feature matrix to detect the ADRs. Feature matrix, which is
extracted from big medical data from The Health Improvement Network (THIN)
database, is created to characterize the medical events for the patients who
take drugs. Feature matrix builds the foundation for the irregular and big
medical data. Then feature selection methods are performed on feature matrix to
detect the significant features. Finally the ADRs can be located based on the
significant features. The experiments are carried out on three drugs:
Atorvastatin, Alendronate, and Metoclopramide. Major side effects for each drug
are detected and better performance is achieved compared to other computerized
methods. The detected ADRs are based on computerized methods, further
investigation is needed.
| arxiv topic:cs.LG cs.CE |
arxiv_dataset-55331409.0875 | Massive MIMO with Non-Ideal Arbitrary Arrays: Hardware Scaling Laws and
Circuit-Aware Design
cs.IT math.IT
Massive multiple-input multiple-output (MIMO) systems are cellular networks
where the base stations (BSs) are equipped with unconventionally many antennas,
deployed on co-located or distributed arrays. Huge spatial degrees-of-freedom
are achieved by coherent processing over these massive arrays, which provide
strong signal gains, resilience to imperfect channel knowledge, and low
interference. This comes at the price of more infrastructure; the hardware cost
and circuit power consumption scale linearly/affinely with the number of BS
antennas $N$. Hence, the key to cost-efficient deployment of large arrays is
low-cost antenna branches with low circuit power, in contrast to today's
conventional expensive and power-hungry BS antenna branches. Such low-cost
transceivers are prone to hardware imperfections, but it has been conjectured
that the huge degrees-of-freedom would bring robustness to such imperfections.
We prove this claim for a generalized uplink system with multiplicative
phase-drifts, additive distortion noise, and noise amplification. Specifically,
we derive closed-form expressions for the user rates and a scaling law that
shows how fast the hardware imperfections can increase with $N$ while
maintaining high rates. The connection between this scaling law and the power
consumption of different transceiver circuits is rigorously exemplified. This
reveals that one can make the circuit power increase as $\sqrt{N}$, instead of
linearly, by careful circuit-aware system design.
| arxiv topic:cs.IT math.IT |
arxiv_dataset-55341409.0975 | Successive spin-flop transitions of Neel-type antiferromagnet
Li$_2$MnO$_3$ single crystal with honeycomb-lattice
cond-mat.str-el cond-mat.mtrl-sci
We have carried out high magnetic field studies of single-crystalline
Li$_2$MnO$_3$, a honeycomb lattice antiferromagnet. Its magnetic phase diagram
was mapped out using magnetization measurements at applied fields up to 35 T.
Our results show that it undergoes two successive meta-magnetic transitions
around 9 T fields applied perpendicular to the ab-plane (along the c*-axis).
These phase transitions are completely absent in the magnetization measured
with field applied along the ab-plane. In order to understand this magnetic
phase diagram, we developed a mean-field model starting from the correct
Neel-type magnetic structure, consistent with our single crystal neutron
diffraction data at zero field. Our model calculations succeeded in explaining
the two meta-magnetic transitions that arise when Li$_2$MnO$_3$ enters two
different spin-flop phases from the zero field Neel phase.
| arxiv topic:cond-mat.str-el cond-mat.mtrl-sci |
arxiv_dataset-55351409.1075 | Tur\'an type inequalities for confluent hypergeometric functions of the
second kind
math.CA
In this paper we deduce some tight Tur\'an type inequalities for Tricomi
confluent hypergeometric functions of the second kind, which in some cases
improve the existing results in the literature. We also give alternative proofs
for some already established Tur\'an type inequalities. Moreover, by using
these Tur\'an type inequalities, we deduce some new inequalities for Tricomi
confluent hypergeometric functions of the second kind. The key tool in the
proof of the Tur\'an type inequalities is an integral representation for a
quotient of Tricomi confluent hypergeometric functions, which arises in the
study of the infinite divisibility of the Fisher-Snedecor $F$ distribution.
| arxiv topic:math.CA |
arxiv_dataset-55361409.1175 | Pricing Spread Options under Stochastic Correlation and Jump-Diffusion
Models
q-fin.PR
This paper examines the problem of pricing spread options under some models
with jumps driven by Compound Poisson Processes and stochastic volatilities in
the form of Cox-Ingersoll-Ross(CIR) processes. We derive the characteristic
function for two market models featuring joint normally distributed jumps,
stochastic volatility, and different stochastic dependence structures. With the
use of Fast Fourier Transform(FFT) we accurately compute spread option prices
across a variety of strikes and initial price vectors at a very low
computational cost when compared to Monte Carlo pricing methods. We also look
at the sensitivities of the prices to the model specifications and find strong
dependence on the selection of the jump and stochastic volatility parameters.
Our numerical implementation is based on the method developed by Hurd and Zhou
(2009).
| arxiv topic:q-fin.PR |
arxiv_dataset-55371409.1275 | La fibration de Hitchin-Frenkel-Ngo et son complexe d'intersection
math.GR math.AG math.NT math.RT
In this article, we construct the Hitchin fibration for groups following the
scheme outlined by Frenkel-Ngo in the case of SL_{2}. This construction uses as
a decisive tool the Vinberg's semigroup. The total space of Hitchin is obtained
by taking the fiber product of the Hecke stack with the diagonal of the stack
of G-bundles $Bun_{G}$; we prove a transversality statement between the
intersection complex of the Hecke stack and the diagonal of $Bun_{G}$, over a
sufficiently big open subset, in order to get local applications, such that the
fundamental lemma for the spherical Hecke algebra. Along the proof of this
theorem, we establish a result concerning the integral conjugacy classes of the
points of a simply connected group in a local field.
| arxiv topic:math.GR math.AG math.NT math.RT |
arxiv_dataset-55381409.1375 | Gravitational radiation from magnetically funnelled supernova fallback
onto a magnetar
astro-ph.HE
Protomagnetars spun up to millisecond rotation periods by supernova fallback
are predicted to radiate gravitational waves via hydrodynamic instabilities for
~ 10^2 s before possibly collapsing to form a black hole. It is shown that
magnetic funnelling of the accretion flow (i) creates a magnetically confined
polar mountain, which boosts the gravitational wave signal, and (ii) "buries"
the magnetic dipole moment, delaying the propeller phase and assisting black
hole formation.
| arxiv topic:astro-ph.HE |
arxiv_dataset-55391409.1475 | Quantum correlation and entanglement between an ionizing system and a
neighbor atom interacting directly and via a quantized field
quant-ph
Quantum correlations between two neighbor atoms are studied. It is assumed
that one atomic system comprises a single auto-ionizing level and the other
atom does not contain any auto-ionizing level. The excitation of both atoms is
achieved by the interaction with the same mode of the quantized field. It is
shown that the long-time behavior of two atoms exhibits quantum correlations
even when the atoms do not interact directly. This can be shown using the
optical excitation of the neighbor atom. Also a measure of entanglement of two
atoms can be applied after reduction of the continuum to two levels.
| arxiv topic:quant-ph |
arxiv_dataset-55401409.1575 | Nonlocal Measurements via Quantum Erasure
quant-ph
Non-local observables play an important role in quantum theory, from Bell
inequalities and various post-selection paradoxes to quantum error correction
codes. Instantaneous measurement of these observables is known to be a
difficult problem, especially when the measurements are projective. The
standard von Neumann Hamiltonian used to model projective measurements cannot
be implemented directly in a non-local scenario and can, in some cases, violate
causality. We present a scheme for effectively generating the von Neumann
Hamiltonian for non-local observables without the need to communicate and
adapt. The protocol can be used to perform weak and strong (projective)
measurements, as well as measurements at any intermediate strength. It can also
be used in practical situations beyond non-local measurements. We show how the
protocol can be used to probe a version of Hardy's paradox with both weak and
strong measurements. The outcomes of these measurements provide a non-intuitive
picture of the pre- and post-selected system. Our results shed new light on the
interplay between quantum measurements, uncertainty, non-locality, causality
and determinism.
| arxiv topic:quant-ph |
arxiv_dataset-55411409.1675 | Cooperative effects and disorder: A scaling analysis of the spectrum of
the effective atomic Hamiltonian
cond-mat.mes-hall
We study numerically the spectrum of the non-Hermitian effective Hamiltonian
that describes the dipolar interaction of a gas of $N\gg 1$ atoms with the
radiation field. We analyze the interplay between cooperative effects and
disorder for both scalar and vectorial radiation fields. We show that for dense
gases, the resonance width distribution follows, both in the scalar and
vectorial cases, a power law $P(\Gamma) \sim \Gamma^{-4/3}$ that originates
from cooperative effects between more than two atoms. This power law is
different from the $ P(\Gamma) \sim \Gamma^{-1}$ behavior, which has been
considered as a signature of Anderson localization of light in random systems.
We show that in dilute clouds, the center of the energy distribution is
described by Wigner's semicircle law in the scalar and vectorial cases. For
dense gases, this law is replaced in the vectorial case by the Laplace
distribution. Finally, we show that in the scalar case the degree of resonance
overlap increases as a power law of the system size for dilute gases, but
decays exponentially with the system size for dense clouds.
| arxiv topic:cond-mat.mes-hall |
arxiv_dataset-55421409.1775 | Effect of Size of the Computational Domain on Spherical Nonlinear
Force-Free Modeling of Coronal Magnetic Field Using SDO/HMI Data
astro-ph.SR
The solar coronal magnetic field produces solar activity, including extremely
energetic solar flares and coronal mass ejections (CMEs). Knowledge of the
structure and evolution of the magnetic field of the solar corona is important
for investigating and understanding the origins of space weather. Although the
coronal field remains difficult to measure directly, there is considerable
interest in accurate modeling of magnetic fields in and around sunspot regions
on the Sun using photospheric vector magnetograms as boundary data. In this
work, we investigate effects of the size of the domain chosen for coronal
magnetic field modeling on resulting model solution. We apply spherical
Optimization procedure to vector magnetogram data of Helioseismic and Magnetic
Imager (HMI) onboard Solar Dynamics Observatory (SDO) with four Active Region
observed on 09 March 2012 at 20:55UT. The results imply that quantities like
magnetic flux density, electric current density and free magnetic energy
density of ARs of interest are significantly different from the corresponding
quantities obtained in the same region within the wider field of view. The
difference is even more pronounced in the regions where there are connections
to outside the domain.
| arxiv topic:astro-ph.SR |
arxiv_dataset-55431409.1875 | Theory of Coherent Van der Waals Matter
cond-mat.soft cond-mat.mtrl-sci cond-mat.stat-mech cond-mat.str-el
We explain in depth the previously proposed theory of the coherent Van der
Waals(cVdW) interaction - the counterpart of Van der Waals (VdW) force -
emerging in spatially coherently fluctuating electromagnetic fields. We show
that cVdW driven matter is dominated by many body interactions, which are
significantly stronger than those found in standard Van der Waals (VdW)
systems. Remarkably, the leading 2- and 3-body interactions are of the same
order with respect to the distance $(\propto R^{-6})$, in contrast to the
usually weak VdW 3-body effects ($\propto R^{-9}$). From a microscopic theory
we show that the anisotropic cVdW many body interactions drive the formation of
low-dimensional structures such as chains, membranes and vesicles with very
unusual, non-local properties. In particular, cVdW chains display a
logarithmically growing stiffness with the chain length, while cVdW membranes
have a bending modulus growing linearly with their size. We argue that the cVdW
anisotropic many body forces cause local cohesion but also a negative effective
"surface tension". We conclude by deriving the equation of state for cVdW
materials and propose new experiments to test the theory, in particular the
unusual 3-body nature of cVdW.
| arxiv topic:cond-mat.soft cond-mat.mtrl-sci cond-mat.stat-mech cond-mat.str-el |
arxiv_dataset-55441409.1975 | GeneNetMiner: accurately mining gene regulatory networks from literature
q-bio.MN q-bio.GN
GeneNetMiner is standalone software which parses the sentences of iHOP and
captures regulatory relations. The regulatory relations are either gene gene
regulations or gene biological processes relations. Capturing of gene
biological process relations is a unique feature for the tools of this kind.
These relations can be used to build up gene regulatory networks for specific
biological processes, diseases, or phenotypes. Users are able to search genes
and biological processes to find the regulatory relationships between them.
Each regulatory relationship has been assigned a confidence score, which
indicates the probability of the true relation. Furthermore, it reports the
sentence containing the queried terms, which allows users to manually checking
whether the relation is true if they wish. GeneNetMiner is able to accurately
capture the regulatory relationships between genes from literature.
| arxiv topic:q-bio.MN q-bio.GN |
arxiv_dataset-55451409.2075 | Quantum Monte Carlo study of the $S_4$ symmetric microscopic model for
iron-based superconductors
cond-mat.str-el
The $S_4$ symmetric microscopic model with two iso-spin components has been
studied via constrained-path quantum Monte Carlo simulation. Our results
demonstrate a stable $(\pi,0)$ or $(0,\pi)$ magnetic order which is
significantly enhanced on increasing both the Coulomb repulsion $U$ and Hund's
coupling strength $J$. Also, our simulation indicates that the magnetic order
tends to be in an orthomagnetic one, in which the nearest-neighbour magnetic
moment are orthogonal to each other, rather than in a collinear
antiferromagnetic state. Interestingly, when the system is doped away from half
filling, the magnetic order is obviously elevated in the low doping density,
and then significantly suppressed when more electrons are introduced.
Meanwhile, we find that an $A_{1g}$ $s_{\pm}$-wave pairing dominates all the
singlet nearest-neighbour pairings, and is significantly enhanced via electron
doping.
| arxiv topic:cond-mat.str-el |
arxiv_dataset-55461409.2175 | No-Free-Lunch Theorems in the continuum
math.OC math.PR
No-Free-Lunch Theorems state, roughly speaking, that the performance of all
search algorithms is the same when averaged over all possible objective
functions. This fact was precisely formulated for the first time in a now
famous paper by Wolpert and Macready, and then subsequently refined and
extended by several authors, always in the context of a set of functions with
discrete domain and codomain. Recently, Auger and Teytaud have shown that for
continuum domains there is typically no No-Free-Lunch theorems. In this paper
we provide another approach, which is simpler, requires less assumptions,
relates the discrete and continuum cases, and that we believe that clarifies
the role of the cardinality and structure of the domain.
| arxiv topic:math.OC math.PR |
arxiv_dataset-55471409.2275 | New Observational Constraints to Milky Way Chemodynamical models
astro-ph.SR astro-ph.GA
Galactic Archaeology, i.e. the use of chemo-dynamical information for stellar
samples covering large portions of the Milky Way to infer the dominant
processes involved in its formation and evolution, is now a powerful method
thanks to the large recently completed and ongoing spectroscopic surveys. It is
now important to ask the right questions when analyzing and interpreting the
information contained in these rich datasets. To this aim, we have developed a
chemodynamical model for the Milky Way that provides quantitative predictions
to be compared with the chemo-kinematical properties extracted from the stellar
spectra. Three key parameters are needed to make the comparison between data
and model predictions useful in order to advance in the field, namely: precise
proper-motions, distances and ages. The uncertainties involved in the estimate
of ages and distances for field stars are currently the main obstacles in the
Galactic Archaeology method. Two important developments might change this
situation in the near future: asteroseismology and the now launched Gaia. When
combined with the large datasets from surveys like RAVE, SEGUE, LAMOST,
Gaia-ESO, APOGEE , HERMES and the future 4MOST we will have the basic
ingredients for the reconstruction of the MW history in hands. In the light of
these observational advances, the development of detailed chemo-dynamical
models tailored to the Milky Way is urgently needed in the field. Here we show
the steps we have taken, both in terms of data analysis and modelling. The
examples shown here illustrate how powerful can the Galactic Archaeology method
become once ages and distances are known with better precision than what is
currently feasible.
| arxiv topic:astro-ph.SR astro-ph.GA |
arxiv_dataset-55481409.2375 | Towards Architectural Programming of Embedded Systems
cs.SE
Integrating architectural elements with a modern programming language is
essential to ensure a smooth combination of architectural design and
programming. In this position statement, we motivate a combination of
architectural description for distributed, asynchronously communicating systems
and Java as an example for such an integration. The result is an ordinary
programming language, that exhibits architecture, data structure and behavior
within one view. Mappings or tracing between different views is unnecessary. A
prototypical implementation of a compiler demonstrates the possibilities and
challenges of architectural programming.
| arxiv topic:cs.SE |
arxiv_dataset-55491409.2475 | Distributed Resource Allocation in 5G Cellular Networks
cs.NI cs.IT math.IT
The 5G cellular wireless systems will have a multi-tier architecture
consisting of macrocells, different types of licensed small cells and D2D
networks to serve users with different quality-of-service (QoS) requirements in
a spectrum efficient manner. Distributed resource allocation and interference
management is one of the fundamental research challenges for such multi-tier
heterogeneous networks. In this chapter, we consider the radio resource
allocation problem in a multi-tier orthogonal frequency division multiple
access (OFDMA)-based cellular (e.g., 5G LTE-A) network. In particular, we
present three novel approaches for distributed resource allocation in such
networks utilizing the concepts of stable matching, factor-graph based message
passing, and distributed auction. We illustrate each of the modeling schemes
with respect to a practical radio resource allocation problem. In particular,
we consider a multi-tier network consisting a macro base station (MBS), a set
of small cell base stations (SBSs) and corresponding small cell user equipments
(SUEs), as well as D2D user equipments (DUEs). There is a common set of radio
resources (e.g., resource blocks [RBs]) available to the network tiers (e.g.,
MBS, SBSs and DUEs). The SUEs and DUEs use the available resources (e.g., RB
and power level) in an underlay manner as long as the interference caused to
the macro tier (e.g., macro user equipments [MUEs]) remains below a given
threshold. Followed by a brief theoretical overview of the modeling tools
(e.g., stable matching, message passing and auction algorithm), we present the
distributed solution approaches for the resource allocation problem in the
aforementioned network setup. We also provide a brief qualitative comparison in
terms of various performance metrics such as complexity, convergence, algorithm
overhead etc.
| arxiv topic:cs.NI cs.IT math.IT |
arxiv_dataset-55501409.2575 | Custom v. Standardized Risk Models
q-fin.PM q-fin.RM
We discuss when and why custom multi-factor risk models are warranted and
give source code for computing some risk factors. Pension/mutual funds do not
require customization but standardization. However, using standardized risk
models in quant trading with much shorter holding horizons is suboptimal: 1)
longer horizon risk factors (value, growth, etc.) increase noise trades and
trading costs; 2) arbitrary risk factors can neutralize alpha; 3)
"standardized" industries are artificial and insufficiently granular; 4)
normalization of style risk factors is lost for the trading universe; 5)
diversifying risk models lowers P&L correlations, reduces turnover and market
impact, and increases capacity. We discuss various aspects of custom risk model
building.
| arxiv topic:q-fin.PM q-fin.RM |
arxiv_dataset-55511409.2675 | Comments on the Neyman-Fisher Controversy and Its Consequences
stat.ME
The Neyman-Fisher controversy considered here originated with the 1935
presentation of Jerzy Neyman's Statistical Problems in Agricultural
Experimentation to the Royal Statistical Society. Neyman asserted that the
standard ANOVA F-test for randomized complete block designs is valid, whereas
the analogous test for Latin squares is invalid in the sense of detecting
differentiation among the treatments, when none existed on average, more often
than desired (i.e., having a higher Type I error than advertised). However,
Neyman's expressions for the expected mean residual sum of squares, for both
designs, are generally incorrect. Furthermore, Neyman's belief that the Type I
error (when testing the null hypothesis of zero average treatment effects) is
higher than desired, whenever the expected mean treatment sum of squares is
greater than the expected mean residual sum of squares, is generally incorrect.
Simple examples show that, without further assumptions on the potential
outcomes, one cannot determine the Type I error of the F-test from expected
sums of squares. Ultimately, we believe that the Neyman-Fisher controversy had
a deleterious impact on the development of statistics, with a major consequence
being that potential outcomes were ignored in favor of linear models and
classical statistical procedures that are imprecise without applied contexts.
| arxiv topic:stat.ME |
arxiv_dataset-55521409.2775 | Ks band secondary eclipses of WASP-19b and WASP-43b with the
Anglo-Australian Telescope
astro-ph.EP
We report new Ks band secondary eclipse observations for the hot-Jupiters
WASP-19b and WASP-43b. Using the IRIS2 infrared camera on the Anglo-Australian
Telescope (AAT), we measured significant secondary eclipses for both planets,
with depths of 0.287 -0.020/+0.020% and 0.181 -0.027/+0.027% for WASP-19b and
WASP-43b respectively. We compare the observations to atmosphere models from
the VSTAR line-by-line radiative transfer code, and examine the effect of C/O
abundance, top layer haze, and metallicities on the observed spectra. We
performed a series of signal injection and recovery exercises on the observed
light curves to explore the detection thresholds of the AAT+IRIS2 facility. We
find that the optimal photometric precision is achieved for targets brighter
than Kmag = 9, for which eclipses as shallow as 0.05% are detectable at >5
sigma significance.
| arxiv topic:astro-ph.EP |
arxiv_dataset-55531409.2875 | Global Optimization for Future Gravitational Wave Detectors' Sites
astro-ph.IM
We consider the optimal site selection of future generations of gravitational
wave detectors. Previously, Raffai et al. optimized a 2-detector network with a
combined figure of merit. This optimization was extended to networks with more
than two detectors in a limited way by first fixing the parameters of all other
component detectors. In this work we now present a more general optimization
that allows the locations of all detectors to be simultaneously chosen. We
follow the definition of Raffai et al. on the metric that defines the
suitability of a certain detector network. Given the locations of the component
detectors in the network, we compute a measure of the network's ability to
distinguish the polarization, constrain the sky localization and reconstruct
the parameters of a gravitational wave source. We further define the
`flexibility index' for a possible site location, by counting the number of
multi-detector networks with a sufficiently high Figure of Merit that include
that site location. We confirm the conclusion of Raffai et al., that in terms
of flexibility index as defined in this work, Australia hosts the best
candidate site to build a future generation gravitational wave detector. This
conclusion is valid for either a 3-detector network or a 5-detector network.
For a 3-detector network site locations in Northern Europe display a comparable
flexibility index to sites in Australia. However for a 5-detector network,
Australia is found to be a clearly better candidate than any other location.
| arxiv topic:astro-ph.IM |
arxiv_dataset-55541409.2975 | Proximity effects at the interface of a superconductor and a topological
insulator in NbN - Bi_2Se_3 thin film bilayers
cond-mat.supr-con
In a search for a simple proximity system of a topological insulator and a
superconductor for studying the role of surface versus bulk effects by gating,
we report here on a first step toward this goal, namely the choice of such a
system and its characterization. We chose to work with thin film bilayers of
grainy 5 nm thick NbN films as the superconductor, overlayed with 20 nm thick
topological layer of $\rm Bi_2Se_3$ and compare the transport results to those
obtained on a 5 nm thick reference NbN film on the same wafer. Bilayers with
ex-situ and in-situ prepared $\rm NbN-Bi_2Se_3$ interfaces were studied and two
kinds of proximity effects were found. At high temperatures just below the
superconducting transition, all bilayers showed a conventional proximity effect
where the topological $\rm Bi_2Se_3$ suppresses the onset or mid-transition
$T_c$ of the superconducting NbN films by about 1 K. At low temperatures, a
cross-over of the resistance versus temperature curves of the bilayer and
reference NbN film occurs, where the bilayers show enhancement of $T_c(R=0)$,
$I_c$ (the supercurrent) and the Andreev conductance, as compared to the bare
NbN films. This indicates that superconductivity is induced in the $\rm
Bi_2Se_3$ layer at the interface region in between the NbN grains. Thus an
inverse proximity effect in the topological material is demonstrated.
| arxiv topic:cond-mat.supr-con |
arxiv_dataset-55551409.3075 | Some surprising results of the Kohn-Sham Density Functional
cond-mat.mtrl-sci
For some insulators we present a procedure to determine an electronic density
leading to a lower energy than that of the Kohn-Sham ground state.
| arxiv topic:cond-mat.mtrl-sci |
arxiv_dataset-55561409.3175 | A nonlinear plasma retroreflector for single pulse Compton
backscattering
physics.plasm-ph physics.acc-ph
Compton scattered x-rays can be generated using a configuration consisting of
a single, ultra-intense laser pulse, and a shaped gas target. The gas target
incorporates a hydrodynamically formed density spike, which nonlinearly
scatters the incident pump radiation, to produce a counter-propagating
electromagnetic wiggler. This self-generated wiggler field Compton scatters
from electrons accelerated in the laser wakefield of the pump radiation. The
nonlinear scattering mechanism in the density spike is examined theoretically
and numerically in order to optimize the Compton scattered radiation. It is
found that narrow-band x-rays are produced by moderate intensity pump radiation
incident on the quarter-critical surface of the density spike, while high
fluence, broadband x-rays are produced by high intensity pump radiation
reflected near the critical surface.
| arxiv topic:physics.plasm-ph physics.acc-ph |
arxiv_dataset-55571409.3275 | Efficient Soft-Input Soft-Output MIMO Chase Detectors for arbitrary
number of streams
cs.IT math.IT
We present novel soft-input soft-output (SISO) multiple-input multiple-output
(MIMO) detectors based on the Chase detection principle [1] in the context of
iterative and decoding (IDD). The proposed detector complexity is linear in the
signal modulation constellation size and the number of spatial streams. Two
variants of the SISO detector are developed, referred to as SISO B-Chase and
SISO L-Chase. An efficient method is presented that uses the decoder output to
modulate the signal constellation decision boundaries inside the detector
leading to the SISO detector architecture. The performance of these detectors
significantly improves with just a few number of IDD iterations. The effect of
transmit and receive antenna correlation is simulated. For the high-correlation
case, the superiority of SISO B-Chase over the SISO L-Chase is demonstrated.
| arxiv topic:cs.IT math.IT |
arxiv_dataset-55581409.3375 | Analytic description of SU(3) lattice thermodynamics in the whole
temperature range within the mass gap approach
hep-ph
A general approach how to analytically describe and understand $SU(3)$
lattice thermodynamics in the whole temperature range $[0, \infty)$ is
formulated and used. It is based on the effective potential approach for
composite operators properly extended to non-zero temperature and density. This
makes it possible to introduce into this general formalism the mass gap, which
is responsible for the large-scale dynamical structure of the QCD ground state.
The mass gap dependent gluon plasma pressure adjusted by this approach to the
corresponding lattice data is shown to be a continuously growing function of
temperature being thus differentiable in every point of its domain. At the same
time, the entropy and energy densities have finite jump discontinuities at some
characteristic temperature $T_c = 266.5 \ \MeV$ with latent heat
$\epsilon_{LH}= 1.41$. This is a firm evidence of the first-order phase
transition in $SU(3)$ pure gluon plasma. The heat capacity has a $\delta$-type
singularity (an essential discontinuity) at $T_c$, so that the velocity of
sound squared becomes zero at this point. All the independent thermodynamic
quantities are exponentially suppressed below $T_c$ and rather slowly approach
their respective Stefan-Boltzmann limits at high temperatures. Those
thermodynamic quantities which are the ratios of their independent counterparts
such as conformity, conformality and the velocity of sound squared approach
their Stefan-Boltzmann limits rather rapidly and demonstrate a non-trivial
dependence on the temperature below $T_c$. We also calculate the trace anomaly
relation (the interaction measure) and closely related to it the gluon
condensate, which are especially sensitive to the non-perturbative effects. An
analytical description of the dynamical structure of $SU(3)$ gluon plasma is
given.
| arxiv topic:hep-ph |
arxiv_dataset-55591409.3475 | Piecewise straightening and Lipschitz simplicial volume
math.GT math.DG
We study the Lipschitz simplicial volume, which is a metric version of the
simplicial volume. We introduce the piecewise straightening procedure for
singular chains, which allows us to generalize the proportionality principle
and the product inequality to the case of complete Riemannian manifolds of
finite volume with sectional curvature bounded from above. We obtain also yet
another proof of the proportionality principle in the compact case by a direct
approximation of the smearing map.
| arxiv topic:math.GT math.DG |
arxiv_dataset-55601409.3575 | AdS/CFT Duality User Guide
hep-th cond-mat.str-el gr-qc hep-ph nucl-th
This is the draft/updated version of a textbook on "real-world" applications
of the AdS/CFT duality for beginning graduate students in particle physics and
for researchers in the other fields. The aim of this book is to provide
background materials such as string theory, general relativity, nuclear
physics, nonequilibrium physics, and condensed-matter physics as well as some
key applications of the AdS/CFT duality in a single textbook. Contents: (1)
Introduction, (2) General relativity and black holes, (3) Black holes and
thermodynamics, (4) Strong interaction and gauge theories, (5) The road to
AdS/CFT, (6) The AdS spacetime, (7) AdS/CFT - equilibrium, (8) AdS/CFT - adding
probes, (9) Basics of nonequilibrium physics, (10) AdS/CFT - nonequilibrium,
(11) Other AdS spacetimes, (12) Applications to quark-gluon plasma, (13) Basics
of phase transition, (14) AdS/CFT - phase transition, (15) Exercises.
| arxiv topic:hep-th cond-mat.str-el gr-qc hep-ph nucl-th |
arxiv_dataset-55611409.3675 | Microcontroller-based locking in optics experiments
physics.optics physics.ins-det quant-ph
Optics experiments critically require the stable and accurate locking of
relative phases between light beams or the stabilization of Fabry-Perot cavity
lengths. Here, we present a simple and inexpensive technique based on a
stand-alone microcontroller unit to perform such tasks. Easily programmed in C
language, this reconfigurable digital locking system also enables automatic
relocking and sequential functioning. Different algorithms are detailed and
applied to fringe locking and to low- and high-finesse optical cavity
stabilization, without the need of external modulations or error signals. This
technique can readily replace a number of analog locking systems advantageously
in a variety of optical experiments.
| arxiv topic:physics.optics physics.ins-det quant-ph |
arxiv_dataset-55621409.3775 | Dark Energy and Mass Generation
hep-ph astro-ph.CO hep-th
We consider a set of solutions for a massless quartic scalar field, recently
devised, that satisfy a massive dispersion relation. We show that such
solutions have the property to give the correct behavior for the equation of
state of the dark energy. It seen that conformal invariance is restored and the
mass gap goes to zero on a time scale determined by the Hubble constant and the
strength of the self-interaction of the scalar field. When conformal invariance
is restored, the equation of state for the dark energy can apply.
| arxiv topic:hep-ph astro-ph.CO hep-th |
arxiv_dataset-55631409.3875 | $L^{p}$ estimates for the bilinear Hilbert transform for $1/2<p\leq2/3$:
A counterexample and generalizations to non-smooth symbols
math.CA
M. Lacey and C. Thiele proved in [27] (Annals of Math. (1997)) and [28]
(Annals of Math. (1999)) that the bilinear Hilbert transform maps
$L^{p_1}\times L^{p_2}\rightarrow L^{p}$ boundedly when
$\frac{1}{p_1}+\frac{1}{p_2}=\frac{1}{p}$ with $1<p_{1}, \, p_{2}\leq\infty$
and $\frac{2}{3}<p<\infty$. Whether the $L^p$ estimates hold in the range $p\in
(1/2,2/3]$ has remained an open problem since then. In this paper, we prove
that the bilinear Hilbert transform does not map $\mathcal{F}L^{p'_{1}}\times
L^{p_{2}}\rightarrow L^{p}$ for $p_1<2$ and $L^{p_{1}}\times
\mathcal{F}L^{p'_{2}}\rightarrow L^{p}$ for $p_2<2$ boundedly (Theorem 1.2). In
particular, this shows that the bilinear Hilbert transform neither maps
$\mathcal{F}L^{p'_{1}}\times L^{p_{2}}\rightarrow L^{p}$ nor $L^{p_{1}}\times
\mathcal{F}L^{p'_{2}}\rightarrow L^{p}$ for $\frac{1}{2}<p<\frac{2}{3}$.
Nevertheless, we can establish $L^p$ estimates for the bilinear Fourier
multipliers whose symbols are not identical to but arbitrarily close to that of
the bilinear Hilbert transform in the full range $p\in(1/2,\infty)$ (Theorem
1.3).
| arxiv topic:math.CA |
arxiv_dataset-55641409.3975 | Floer theory and topology of $Diff (S^2)$
math.SG math.DG
We say that a fixed point of a diffeomorphism is non-degenerate if 1 is not
an eigenvalue of the linearization at the fixed point. We use
pseudo-holomorphic curves techniques to prove the following: the inclusion map
$$i: \text{Diff} ^{1} (S ^{2} ) \to \text{Diff} (S^2)$$ vanishes on all
homotopy groups, where $\text{Diff} ^{1} (S^{2} ) \subset \text {Diff} (S^{2}
)$ denotes the space of orientation preserving diffeomorphisms of $S ^{2} $
with a prescribed non-degenerate fixed point. This complements the classical
results of Smale and Eels and Earl.
| arxiv topic:math.SG math.DG |
arxiv_dataset-55651409.4075 | Interplay and Characterization of Dark Matter Searches at Colliders and
in Direct Detection Experiments
hep-ex hep-ph
In this White Paper we present and discuss a concrete proposal for the
consistent interpretation of Dark Matter searches at colliders and in direct
detection experiments. Based on a specific implementation of simplified models
of vector and axial-vector mediator exchanges, this proposal demonstrates how
the two search strategies can be compared on an equal footing.
| arxiv topic:hep-ex hep-ph |
arxiv_dataset-55661409.4175 | Reducible deformations and smoothing of primitive multiple curves
math.AG
A primitive multiple curve is a Cohen-Macaulay irreducible projective curve
$Y$ that can be locally embedded in a smooth surface, and such that $C=Y_{red}$
is smooth. In this case, $L={\mathcal I}_C/{\mathcal I}_C^2$ is a line bundle
on $C$.
This paper continues the study of deformations of $Y$ to curves with smooth
irreducible components, when the number of components is maximal (it is then
the multiplicity $n$ of $Y$). We prove that a primitive double curve can be
deformed to reduced curves with smooth components intersecting transversally if
and only if $h^0(L^{-1})\not=0$. We give also some properties of reducible
deformations in the case of multiplicity $n>2$.
| arxiv topic:math.AG |
arxiv_dataset-55671409.4275 | Interference effects in the two-dimensional scattering of microcavity
polaritons by an obstacle: phase dislocations and resonances
cond-mat.quant-gas
We consider interference effects within the linear description of the
scattering of two-dimensional microcavity polaritons by an obstacle. The
polariton wave may exhibit phase dislocations created by the interference of
the incident and the scattered fields. We describe these structures within the
general framework of singular optics. We also discuss another type of
interference effects appearing due to the formation of (quasi)resonances in the
potential of a repulsive obstacle with sharp boundaries. We discuss the
relevance of our approach for the description of recent experimental results
and propose a criterion for evaluating the importance of nonlinear effects.
| arxiv topic:cond-mat.quant-gas |
arxiv_dataset-55681409.4375 | Quarkonium production and polarization in pp collisions with the CMS
detector
hep-ex hep-ph
The studies of heavy quarkonium inclusive production and polarization at LHC
are becoming crucial to solve the puzzle of hadron formation. The results by
CMS and the other LHC experiments are compactly presented for the five S-wave
states J/Psi, Psi(2S) and Y(nS) (n=1,2,3) and briefly discussed especially in
comparison to the theoretical predictions provided by Non Relativistic QCD.
| arxiv topic:hep-ex hep-ph |
arxiv_dataset-55691409.4475 | `C$_{60}$ spin-charging' with an eye on a quantum computer
physics.atom-ph
A question whether there exists an interaction between the spins of the
endohedral atom $A$@C$_{60}$ and the properties of the confining shell which
might affect the alignment of, or manipulation by, the spins for building a
register for a quantum computer is discussed. It is argued that an effect,
termed the `C$_{60}$ spin-charging' effect, can occur in endohedral atoms and
would affect the operation of a quantum register. The effect is exemplified by
choosing the $\rm 3d$ (Cr and Mn) and $\rm 4d$ (Mo and Tc) transition metal
atoms as well as a rare-earth Eu atom as the case study. A class of high-spin
atoms which are less suitable for building a quantum register is, thus,
identified.
| arxiv topic:physics.atom-ph |
arxiv_dataset-55701409.4575 | Stable Cosparse Recovery via \ell_p-analysis Optimization
cs.IT math.IT
In this paper we study the $\ell_p$-analysis optimization ($0<p\leq1$)
problem for cosparse signal recovery. We establish a bound for recovery error
via the restricted $p$-isometry property over any subspace. We further prove
that the nonconvex $\ell_q$-analysis optimization can do recovery with a lower
sample complexity and in a wider range of cosparsity than its convex
counterpart. In addition, we develop an iteratively reweighted method to solve
the optimization problem under a variational framework. Empirical results of
preliminary computational experiments illustrate that the nonconvex method
outperforms its convex counterpart.
| arxiv topic:cs.IT math.IT |
arxiv_dataset-55711409.4675 | Heavy-flavour production and multiplicity dependence in pp and p--Pb
collisions with ALICE
nucl-ex
The production of heavy quarks in pp collisions provides a precision test of
perturbative QCD calculations at the LHC energies. More complex collision
systems like p--Pb collisions allow studies of cold nuclear matter effects,
such as modifications of the parton distribution functions at small x and of
the $\kt$ broadening effect. We present the ALICE results of prompt D-meson
production as a function of the charged-particle multiplicity, in pp and p--Pb
collisions at $\sqrt{s}=7$ TeV and $\sqrt{s_{NN}}=5.02$ TeV respectively. The
per-event yield of D mesons in different multiplicity and $\pt$ intervals are
compared for pp and p--Pb collisions to study the contribution of multi-parton
interactions to open-charm production. Angular correlations of prompt D mesons
and heavy-flavour decay electrons with charged hadrons in pp and p-Pb
collisions are also shown in different kinematic ranges and compared to pQCD
models. These measurements provide information on the charm fragmentation
processes, on cold nuclear matter effects on charm production, and on the
participation of charm in the collective motion arising in small collision
systems like p-Pb.
| arxiv topic:nucl-ex |
arxiv_dataset-55721409.4775 | The Best and Brightest Metal-Poor Stars
astro-ph.SR astro-ph.GA
The chemical abundances of large samples of extremely metal-poor (EMP) stars
can be used to investigate metal-free stellar populations, supernovae, and
nucleosynthesis as well as the formation and galactic chemical evolution of the
Milky Way and its progenitor halos. However, current progress on the study of
EMP stars is being limited by their faint apparent magnitudes. The acquisition
of high signal-to-noise spectra for faint EMP stars requires a major telescope
time commitment, making the construction of large samples of EMP star
abundances prohibitively expensive. We have developed a new, efficient
selection that uses only public, all-sky APASS optical, 2MASS near-infrared,
and WISE mid-infrared photometry to identify bright metal-poor star candidates
through their lack of molecular absorption near 4.6 microns. We have used our
selection to identify 11,916 metal-poor star candidates with V < 14, increasing
the number of publicly-available candidates by more than a factor of five in
this magnitude range. Their bright apparent magnitudes have greatly eased
high-resolution follow-up observations that have identified seven previously
unknown stars with [Fe/H] <~ -3.0. Our follow-up campaign has revealed that
3.8^{+1.3}_{-1.1}% of our candidates have [Fe/H] <~ -3.0 and
32.5^{+3.0}_{-2.9}% have -3.0 <~ [Fe/H] <~ -2.0. The bulge is the most likely
location of any existing Galactic Population III stars, and an infrared-only
variant of our selection is well suited to the identification of metal-poor
stars in the bulge. Indeed, two of our confirmed metal-poor stars with [Fe/H]
<~ -2.7 are within about 2 kpc of the Galactic Center. They are among the most
metal-poor stars known in the bulge.
| arxiv topic:astro-ph.SR astro-ph.GA |
arxiv_dataset-55731409.4875 | Odd-frequency Two Particle Bose-Einstein Condensate
cond-mat.quant-gas
We introduce the concept of the {\em odd-frequency} Bose Einstein Condensate
(BEC), characterized by the odd frequency/time two-boson expectation value. To
illustrate the concept of odd frequency BEC we present simple classification of
pair boson condensates that explicitly permits this state. We point qualitative
differences of odd-frequency BEC with conventional BEC and introduce the order
parameter and wave function for the odd-frequency BEC.
| arxiv topic:cond-mat.quant-gas |
arxiv_dataset-55741409.4975 | The mysterious optical afterglow spectrum of GRB140506A at z=0.889
astro-ph.GA astro-ph.HE
Context. Gamma-ray burst (GRBs) afterglows probe sightlines to star-forming
regions in distant star-forming galaxies. Here we present a study of the
peculiar afterglow spectrum of the z = 0.889 Swift GRB 140506A. Aims. Our aim
is to understand the origin of the very unusual properties of the absorption
along the line-of-sight. Methods. We analyse spectroscopic observations
obtained with the X-shooter spectrograph mounted on the ESO/VLT at two epochs
8.8 h and 33 h after the burst as well as imaging from the GROND instrument. We
also present imaging and spectroscopy of the host galaxy obtained with the
Magellan telescope. Results. The underlying afterglow appears to be a typical
afterglow of a long-duration GRB. However, the material along the line-of-
sight has imprinted very unusual features on the spectrum. Firstly, there is a
very broad and strong flux drop below 8000 AA (4000 AA in the rest frame),
which seems to be variable between the two spectroscopic epochs. We can
reproduce the flux-drops both as a giant 2175 AA extinction bump and as an
effect of multiple scattering on dust grains in a dense environment. Secondly,
we detect absorption lines from excited H i and He i. We also detect molecular
absorption from CH+ . Conclusions. We interpret the unusual properties of these
spectra as reflecting the presence of three distinct regions along the
line-of-sight: the excited He i absorption originates from an H ii-region,
whereas the Balmer absorption must originate from an associated
photodissociation region. The strong metal line and molecular absorption and
the dust extinction must originate from a third, cooler region along the
line-of-sight. The presence of (at least) three separate regions is reflected
in the fact that the different absorption components have different velocities
relative to the systemic redshift of the host galaxy.
| arxiv topic:astro-ph.GA astro-ph.HE |
arxiv_dataset-55751409.5075 | Sum rules and spectral density flow in QCD and in superconformal
theories
hep-th
We discuss the signature of the anomalous breaking of the superconformal
symmetry in $\mathcal{N}=1$ super Yang Mills theory and its manifestation in
the form of anomaly poles. Moreover, we describe the massive deformations of
the $\mathcal{N}=1$ theory and the spectral densities of the corresponding
anomaly form factors. These are characterized by spectral densities which flow
with the mass deformation and turn the continuum contributions from the
two-particle cuts of the intermediate states into poles, with a single sum rule
satisfied by each component. The poles can be interpreted as signaling the
exchange of a composite axion/dilaton/dilatino (ADD) multiplet in the effective
Lagrangian. We conclude that global anomalous currents characterized by a
single flow in the perturbative picture always predict the existence of
composite interpolating fields.
| arxiv topic:hep-th |
arxiv_dataset-55761409.5175 | Colorful Associahedra and Cyclohedra
math.CO math.MG
Every n-edge colored n-regular graph G naturally gives rise to a simple
abstract n-polytope, the colorful polytope of G, whose 1-skeleton is isomorphic
to G. The paper describes colorful polytope versions of the associahedron and
cyclohedron. Like their classical counterparts, the colorful associahedron and
cyclohedron encode triangulations and flips, but now with the added feature
that the diagonals of the triangulations are colored and adjacency of
triangulations requires color preserving flips. The colorful associahedron and
cyclohedron are derived as colorful polytopes from the edge colored graph whose
vertices represent these triangulations and whose colors on edges represent the
colors of flipped diagonals.
| arxiv topic:math.CO math.MG |
arxiv_dataset-55771409.5275 | On Milnor fibrations of mixed functions, $a_f$-condition and boundary
stability
math.AG
Convenient mixed functions with strongly non-degenerate Newton boundaries
have Milnor fibrations, as the isolatedness of the singularity follows from the
convenience. In this paper, we consider the Milnor fibration for non-convenient
mixed functions. We also study geometric properties such as Thom's $a_f$
condition, the transversality of the nearby fibers and stable boundary property
of the Milnor fibration and their relations.
| arxiv topic:math.AG |
arxiv_dataset-55781409.5375 | Topological Phases of Sound and Light
cond-mat.mes-hall
Topological states of matter are particularly robust, since they exploit
global features insensitive to local perturbations. In this work, we describe
how to create a Chern insulator of phonons in the solid state. The proposed
implementation is based on a simple setting, a dielectric slab with a suitable
pattern of holes. Its topological properties can be wholly tuned in-situ by
adjusting the amplitude and frequency of a driving laser that controls the
optomechanical interaction between light and sound. The resulting chiral,
topologically protected phonon transport along the edges can be probed
completely optically. Moreover, we identify a regime of strong mixing between
photon and phonon excitations, which gives rise to a large set of different
topological phases. This would be an example of a Chern insulator produced from
the interaction between two physically very different particle species, photons
and phonons.
| arxiv topic:cond-mat.mes-hall |
arxiv_dataset-55791409.5475 | A Lattice Path Interpretation of the Diamond Product
math.CO
The diamond product is the poset operation that when applied to the face
lattices of two polytopes results in the face lattice of the Cartesian product
of the polytopes. Application of the diamond product to two Eulerian posets is
a bilinear operation on the cd-indices of the two posets, yielding a product on
cd-polynomials. A lattice path interpretation is provided for this product of
two cd-monomials.
| arxiv topic:math.CO |
arxiv_dataset-55801409.5575 | Renormalized solutions of nonlinear parabolic equations with general
measure data
math.AP
Let $\Omega\subseteq \mathbb{R}^N$ a bounded open set, $N\geq 2$, and let
$p>1$; we prove existence of a renormalized solution for parabolic problems
whose model is $$ \begin{cases} u_{t}-\Delta_{p} u=\mu & \text{in}\
(0,T)\times\Omega,\newline u(0,x)=u_0 & \text{in}\ \Omega,\newline u(t,x)=0
&\text{on}\ (0,T)\times\partial\Omega, \end{cases} $$ where $T>0$ is any
positive constant, $\mu\in M(Q)$ is a any measure with bounded variation over
$Q=(0,T)\times\Omega$, and $u_o\in L^1(\Omega)$, and $-\Delta_{p} u=-{\rm div}
(|\nabla u|^{p-2}\nabla u )$ is the usual $p$-laplacian.
| arxiv topic:math.AP |
arxiv_dataset-55811409.5675 | Beam Energy Dependence of Dielectron Production in Au+Au Collisions from
STAR at RHIC
nucl-ex hep-ex
We present the energy-dependent study of dielectron production in 0-80%
minimum-bias Au+Au collisions at $\sqrt{s_{NN}}$ energies of 19.6, 27, 39, and
62.4 GeV in STAR. Invariant mass ($M_{ee}$) and transverse momentum ($p_T$)
differential measurements of dielectron yields are compared to cocktail
simulations of known hadronic sources and semi-leptonic charmed decays. The
enhancement (excess yield) prominent in the Low-Mass Region (LMR) over the
cocktail at all energies, is further compared to calculations of $\rho$
in-medium modifications. Within statistical and systematic uncertainties, we
find that the model consistently describes this enhancement from SPS up to top
RHIC energies in its $M_{ee}$- as well as $p_T$-dependence. Dielectron
measurements drive the statistics for the future BES Phase-II program, which
promises to improve our understanding of the LMR enhancement's trend with total
baryon densities.
| arxiv topic:nucl-ex hep-ex |
arxiv_dataset-55821409.5775 | Unitarity bounds on scalar dark matter effective interactions at LHC
hep-ph hep-ex
We study the compatibility of the unitarity bound and the 8TeV LHC on the
effective theory of the scalar dark matter. In several signals of effective
interactions, mono-jet with missing energy events are studied. We found that,
at least, if the dark matter mass is about 800GeV or heavier, contributions of
events violating the unitarity are not negligible. The unitarity conditions in
the 14TeV LHC are also calculated.
| arxiv topic:hep-ph hep-ex |
arxiv_dataset-55831409.5875 | Distributed multipoles from a robust basis-space implementation of the
iterated stockholder atoms procedure
cond-mat.mtrl-sci physics.atm-clus physics.chem-ph physics.comp-ph quant-ph
The recently developed iterated stockholder atoms (ISA) approach of
Lillestolen and Wheatley (Chem. Commun. {\bf 2008}, 5909 (2008)) offers a
powerful method for defining atoms in a molecule. However, the real-space
algorithm is known to converge very slowly, if at all. Here we present a
robust, basis-space algorithm of the ISA method and demonstrate its
applicability on a variety of systems. We show that this algorithm exhibits
rapid convergence (taking around 10--80 iterations) with the number of
iterations needed being unrelated to the system size or basis set used.
Further, we show that the multipole moments calculated using this basis-space
ISA method are as good as, or better than those obtained from Stone's
distributed multipole analysis (J. Chem. Theory Comput. {\bf 1}, 1128 (2005) ),
exhibiting better convergence properties and resulting in better behaved
penetration energies. This can have significant consequences in the development
of intermolecular interaction models.
| arxiv topic:cond-mat.mtrl-sci physics.atm-clus physics.chem-ph physics.comp-ph quant-ph |
arxiv_dataset-55841409.5975 | Statistical Power Law due to Reservoir Fluctuations and the Universal
Thermostat Independence Principle
cond-mat.stat-mech
Certain fluctuations in particle number at fixed total energy lead exactly to
a cut-power law distribution in the one-particle energy, via the induced
fluctuations in the phase-space volume ratio. The temperature parameter is
expressed automatically by an equipartition relation, while the q-parameter is
related to the scaled variance and to the expectation value of the particle
number. For the binomial distribution q is smaller, for the negative binomial q
is larger than one. These results also represent an approximation for general
particle number distributions in the reservoir up to second order in the
canonical expansion. For general systems the average phase-space volume ratio
expanded to second order delivers a q parameter related to the heat capacity
and to the variance of the temperature. However, q differing from one leads to
non-additivity of the Boltzmann-Gibbs entropy. We demonstrate that a deformed
entropy, K(S), can be constructed and used for demanding additivity. This
requirement leads to a second order differential equation for K(S). Finally,
the generalized q-entropy formula contains the Tsallis, Renyi and
Boltzmann-Gibbs-Shannon expressions as particular cases. For diverging
temperature variance we obtain a novel entropy formula.
| arxiv topic:cond-mat.stat-mech |
arxiv_dataset-55851409.6075 | The Information Theoretically Efficient Model (ITEM): A model for
computerized analysis of large datasets
cs.LG
This document discusses the Information Theoretically Efficient Model (ITEM),
a computerized system to generate an information theoretically efficient
multinomial logistic regression from a general dataset. More specifically, this
model is designed to succeed even where the logit transform of the dependent
variable is not necessarily linear in the independent variables. This research
shows that for large datasets, the resulting models can be produced on modern
computers in a tractable amount of time. These models are also resistant to
overfitting, and as such they tend to produce interpretable models with only a
limited number of features, all of which are designed to be well behaved.
| arxiv topic:cs.LG |
arxiv_dataset-55861409.6175 | The QCD critical end point driven by an external magnetic field in
asymmetric quark matter
hep-ph
The effect of the isospin/charge asymmetry and an external magnetic field in
the location of the critical end point (CEP) in the QCD phase diagram is
investigated. By using the 2+1 flavor Nambu--Jona-Lasinio model with Polyakov
loop (PNJL), it is shown that the isospin asymmetry shifts the CEP to larger
baryonic chemical potentials and smaller temperatures, and in the presence of a
large enough isospin asymmetry the CEP disappears. Nevertheless, a sufficiently
high external magnetic field can drive the system into a first order phase
transition again.
| arxiv topic:hep-ph |
arxiv_dataset-55871409.6275 | The Enumerative Geometry of Hyperplane Arrangements
math.AG math.CO
We study enumerative questions on the moduli space $\mathcal{M}(L)$ of
hyperplane arrangements with a given intersection lattice $L$. Mn\"ev's
universality theorem suggests that these moduli spaces can be arbitrarily
complicated; indeed it is even difficult to compute the dimension $D =\dim
\mathcal{M}(L)$. Embedding $\mathcal{M}(L)$ in a product of projective spaces,
we study the degree $N=\mathrm{deg} \mathcal{M}(L)$, which can be interpreted
as the number of arrangements in $\mathcal{M}(L)$ that pass through $D$ points
in general position. For generic arrangements $N$ can be computed
combinatorially and this number also appears in the study of the Chow variety
of zero dimensional cycles. We compute $D$ and $N$ using Schubert calculus in
the case where $L$ is the intersection lattice of the arrangement obtained by
taking multiple cones over a generic arrangement. We also calculate the
characteristic numbers for families of generic arrangements in $\mathbb{P}^2$
with 3 and 4 lines.
| arxiv topic:math.AG math.CO |
arxiv_dataset-55881409.6375 | The shifts X-Ray Mn K{\alpha} and 2p spectra of Mn-Heusler alloys
cond-mat.mtrl-sci
X-ray emission K{\alpha}1,2 spectra of Mn in Heusler alloys Co2MnMe (Me = Al,
Ga, Sb), Ni2MnIn, Cu2MnAl were studied. Shifts of Mn K{\alpha}1,2 lines
relatively pure Mn in high-energy region and low-energy shifts of binding
energy Mn 2p XPS is detected. X-ray emission and XPS shifts are in qualitative
agreement.
| arxiv topic:cond-mat.mtrl-sci |
arxiv_dataset-55891409.6475 | "Nonlinear pullbacks" of functions and $L_{\infty}$-morphisms for
homotopy Poisson structures
math.DG math-ph math.MP math.SG
We introduce mappings between spaces of functions on (super)manifolds that
generalize pullbacks with respect to smooth maps but are, in general, nonlinear
(actually, formal). The construction is based on canonical relations and
generating functions. (The underlying structure is a formal category, which is
a "thickening" of the usual category of supermanifolds; it is close to the
category of symplectic micromanifolds and their micromorphisms considered
recently by A. Weinstein and A. Cattaneo--B. Dherin--Weinstein.) There are two
parallel settings, for even and odd functions. As an application, we show how
such nonlinear pullbacks give $L_{\infty}$-morphisms for algebras of functions
on homotopy Schouten or homotopy Poisson manifolds.
| arxiv topic:math.DG math-ph math.MP math.SG |
arxiv_dataset-55901409.6575 | Many-body Majorana operators and the equivalence of parity sectors
cond-mat.mes-hall
The one-dimensional p-wave topological superconductor model with
open-boundary conditions is examined in its topological phase. Using the
eigenbasis of the non-interacting system I show that, provided the interactions
are local and do not result in a closing of the gap, then even and odd parity
sectors are unitarily equivalent. Following on from this, it is possible to
define two many-body operators that connect each state in one sector with a
degenerate counterpart in the sector with opposite parity. This result applies
to all states in the system and therefore establishes, for a long enough wire,
that all even-odd eigenpairs remain essentially degenerate in the presence of
local interactions. Building on this observation I then set out a full
definition of the related many-body Majorana operators and point out that their
structure cannot be fully revealed using cross-correlation data obtained from
the ground state manifold alone. Although all results are formulated in the
context of the 1-dimensional p-wave model, I argue why they should also apply
to more realistic realisations (e.g. the multi-channel p-wave wire and
proximity coupled models) of topological superconductivity.
| arxiv topic:cond-mat.mes-hall |
arxiv_dataset-55911409.6675 | On the classification and modular extendability of E$_0$-semigroups on
factors
math.OA
In this paper we study modular extendability and equimodularity of
endomorphisms and E$_0$-semigroups on factors with respect to f.n.s. weights.
We show that modular extendability is a property that does not depend on the
choice of weights, it is a cocycle conjugacy invariant and it is preserved
under tensoring. We say that a modularly extendable E$_0$-semigroup is of type
EI, EII or EIII if its modular extension is of type I, II or III, respectively.
We prove that all types exist on properly infinite factors.
We also compute the coupling index and the relative commutant index for the
CAR flows and $q$-CCR flows. As an application, by considering repeated tensors
of the CAR flows we show that there are infinitely many non cocycle conjugate
non-extendable $E_0$-semigroups on the hyperfinite factors of types II$_1$,
II$_{\infty}$ and III$_\lambda$, for $\lambda \in (0,1)$.
| arxiv topic:math.OA |
arxiv_dataset-55921409.6775 | A Queueing Network Approach to the Analysis and Control of
Mobility-On-Demand Systems
cs.PF cs.SY
This paper presents a queueing network approach to the analysis and control
of mobility-on-demand (MoD) systems for urban personal transportation. A MoD
system consists of a fleet of vehicles providing one-way car sharing service
and a team of drivers to rebalance such vehicles. The drivers then rebalance
themselves by driving select customers similar to a taxi service. We model the
MoD system as two coupled closed Jackson networks with passenger loss. We show
that the system can be approximately balanced by solving two decoupled linear
programs and exactly balanced through nonlinear optimization. The rebalancing
techniques are applied to a system sizing example using taxi data in three
neighborhoods of Manhattan, which suggests that the optimal vehicle-to-driver
ratio in a MoD system is between 3 and 5. Lastly, we formulate a real-time
closed-loop rebalancing policy for drivers and demonstrate its stability (in
terms of customer wait times) for typical system loads.
| arxiv topic:cs.PF cs.SY |
arxiv_dataset-55931409.6875 | The thermoelectric properties of inhomogeneous holographic lattices
hep-th cond-mat.str-el
We consider inhomogeneous, periodic, holographic lattices of D=4
Einstein-Maxwell theory. We show that the DC thermoelectric conductivity matrix
can be expressed analytically in terms of the horizon data of the corresponding
black hole solution. We numerically construct such black hole solutions for
lattices consisting of one, two and ten wave-numbers. We numerically determine
the AC electric conductivity which reveals Drude physics as well as resonances
associated with sound modes. No evidence for an intermediate frequency scaling
regime is found. All of the monochromatic lattice black holes that we have
constructed exhibit scaling behaviour at low temperatures which is consistent
with the appearance of $AdS_2\times\mathbb{R}^2$ in the far IR at T=0.
| arxiv topic:hep-th cond-mat.str-el |
arxiv_dataset-55941409.6975 | Kepler detection of a new extreme planetary system orbiting the
subdwarf-B pulsator KIC10001893
astro-ph.EP astro-ph.SR
KIC10001893 is one out of 19 subdwarf-B (sdB) pulsators observed by the
Kepler spacecraft in its primary mission. In addition to tens of pulsation
frequencies in the g-mode domain, its Fourier spectrum shows three weak peaks
at very low frequencies, which is too low to be explained in terms of g modes.
The most convincing explanation is that we are seeing the orbital modulation of
three Earth-size planets (or planetary remnants) in very tight orbits, which
are illuminated by the strong stellar radiation. The orbital periods are
P1=5.273, P2=7.807, and P3=19.48 hours, and the period ratios P2/P1=1.481 and
P3/P2=2.495 are very close to the 3:2 and 5:2 resonances, respectively. One of
the main pulsation modes of the star at 210.68 {\mu}Hz corresponds to the third
harmonic of the orbital frequency of the inner planet, suggesting that we see,
for the first time in an sdB star, g-mode pulsations tidally excited by a
planetary companion. The extreme planetary system that emerges from the Kepler
data is very similar to the recent discovery of two Earth-size planets orbiting
the sdB pulsator KIC05807616 (Charpinet et al. 2011a).
| arxiv topic:astro-ph.EP astro-ph.SR |
arxiv_dataset-55951409.7075 | The Challenge of Realizing F-term Axion Monodromy Inflation in String
Theory
hep-th astro-ph.CO
A systematic analysis of possibilities for realizing single-field F-term
axion monodromy inflation via the flux-induced superpotential in type IIB
string theory is performed. In this well-defined setting the conditions arising
from moduli stabilization are taken into account, where we focus on the
complex-structure moduli but ignore the Kaehler moduli sector. Our analysis
leads to a no-go theorem, if the inflaton involves the universal axion. We
furthermore construct an explicit example of F-term axion monodromy inflation,
in which a single axion-like field is hierarchically lighter than all remaining
complex-structure moduli.
| arxiv topic:hep-th astro-ph.CO |
arxiv_dataset-55961409.7175 | Hamiltonian analysis of interacting fluids
hep-th gr-qc
Ideal fluid dynamics is studied as a relativistic field theory with
particular importance on its hamiltonian structure. The Schwinger condition,
whose integrated version yields the stress tensor conservation, is explicitly
verified both in equal-time and light-cone coordinate systems. We also consider
the hamiltonian formulation of fluids interacting with an external gauge field.
The complementary roles of the canonical(Noether) stress tensor and the
symmetric one obtained by metric variation are discussed. Finally, a
non-relativistic reduction of the system in light-cone coordinates has been
carried out which reproduces results found earlier in the literature.
| arxiv topic:hep-th gr-qc |
arxiv_dataset-55971409.7275 | The meaning-frequency law in Zipfian optimization models of
communication
cs.CL physics.data-an physics.soc-ph
According to Zipf's meaning-frequency law, words that are more frequent tend
to have more meanings. Here it is shown that a linear dependency between the
frequency of a form and its number of meanings is found in a family of models
of Zipf's law for word frequencies. This is evidence for a weak version of the
meaning-frequency law. Interestingly, that weak law (a) is not an inevitable of
property of the assumptions of the family and (b) is found at least in the
narrow regime where those models exhibit Zipf's law for word frequencies.
| arxiv topic:cs.CL physics.data-an physics.soc-ph |
arxiv_dataset-55981409.7375 | Tailoring Thermal Radiative Properties with Film-Coupled Concave Grating
Metamaterials
physics.optics cond-mat.mes-hall
This work numerically investigates the radiative properties of film-coupled
metamaterials made of a two-dimensional metallic concave grating on a
continuous metal film separated by an ultrathin dielectric spacer.
Spectrally-selective absorption is demonstrated in the visible and
near-infrared regime, and underlying mechanisms are elucidated to be either
localized magnetic polaritons (MPs) or surface plasmon polaritons (SPPs). The
unique behaviors of MPs and SPPs are explained with the help of electromagnetic
field distributions at respective resonance frequencies. An inductor-capacitor
model is utilized to further confirm the excitation of MP, while dispersion
relation is used to understand the behaviors of different SPP modes. Geometric
effects of ridge width and grating period on the resonance absorption peaks are
discussed. Moreover, directional responses at oblique incidences for different
polarization states are studied. Fundamental understanding gained here will
facilitate the design of novel metamaterials in energy harvesting and sensing
applications.
| arxiv topic:physics.optics cond-mat.mes-hall |
arxiv_dataset-55991409.7475 | Requisite Variety, Autopoiesis, and Self-organization
nlin.AO cs.OH
Ashby's law of requisite variety states that a controller must have at least
as much variety (complexity) as the controlled. Maturana and Varela proposed
autopoiesis (self-production) to define living systems. Living systems also
require to fulfill the law of requisite variety. A measure of autopoiesis has
been proposed as the ratio between the complexity of a system and the
complexity of its environment. Self-organization can be used as a concept to
guide the design of systems towards higher values of autopoiesis, with the
potential of making technology more "living", i.e. adaptive and robust.
| arxiv topic:nlin.AO cs.OH |
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