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arxiv_dataset-105001811.05367 | Prime number theorems for Basmajian-type identities
math.DS math.GT
We obtain asymptotic counting results with error terms for complex
orthospectrum for Schottky groups and orbit counting function for quadratic
polynomials. Moreover, we prove equidistribution of holonomy associated to
these dynamical systems. Our results are obtained by considering generalized
$L$-functions coming from the Basmajian-type identities introduced by the
author in \cite{He}. We study the associated summatory functions using tools
from analytic number theory and Thermodynamic Formalism, namely the Perron's
formula and a Dolgopyat-type estimate on the spectrum of transfer operators.
| arxiv topic:math.DS math.GT |
arxiv_dataset-105011811.05467 | Towards Neural Machine Translation for African Languages
cs.CL cs.LG stat.ML
Given that South African education is in crisis, strategies for improvement
and sustainability of high-quality, up-to-date education must be explored. In
the migration of education online, inclusion of machine translation for
low-resourced local languages becomes necessary. This paper aims to spur the
use of current neural machine translation (NMT) techniques for low-resourced
local languages. The paper demonstrates state-of-the-art performance on
English-to-Setswana translation using the Autshumato dataset. The use of the
Transformer architecture beat previous techniques by 5.33 BLEU points. This
demonstrates the promise of using current NMT techniques for African languages.
| arxiv topic:cs.CL cs.LG stat.ML |
arxiv_dataset-105021811.05567 | Estimation of High-Dimensional Seemingly Unrelated Regression Models
econ.EM
In this paper, we investigate seemingly unrelated regression (SUR) models
that allow the number of equations (N) to be large, and to be comparable to the
number of the observations in each equation (T). It is well known in the
literature that the conventional SUR estimator, for example, the generalized
least squares (GLS) estimator of Zellner (1962) does not perform well. As the
main contribution of the paper, we propose a new feasible GLS estimator called
the feasible graphical lasso (FGLasso) estimator. For a feasible implementation
of the GLS estimator, we use the graphical lasso estimation of the precision
matrix (the inverse of the covariance matrix of the equation system errors)
assuming that the underlying unknown precision matrix is sparse. We derive
asymptotic theories of the new estimator and investigate its finite sample
properties via Monte-Carlo simulations.
| arxiv topic:econ.EM |
arxiv_dataset-105031811.05667 | Finite-size scaling for four-dimensional Higgs-Yukawa model near the
Gaussian fixed point
hep-lat hep-ph
We analyse finite-size scaling behaviour of a four-dimensional Higgs-Yukawa
model near the Gaussian infrared fixed point. Through improving the mean-field
scaling laws by solving one-loop renormalisation group equations, the
triviality property of this model can be manifested in the volume-dependence of
moments of the scalar-field zero mode. The scaling formulae for the moments are
derived in this work with the inclusion of the leading-logarithmic corrections.
To test these formulae, we confront them with data from lattice simulations in
a simpler model, namely the O(4) pure scalar theory, and find numerical
evidence of good agreement. Our results of the finite-size scaling can in
principle be employed to establish triviality of Higgs-Yukawa models, or to
search for alternative scenarios in studying their fixed-point structure, if
sufficiently large lattices can be reached.
| arxiv topic:hep-lat hep-ph |
arxiv_dataset-105041811.05767 | An X-ray spectroscopic search for dark matter and unidentified line
signatures in the Perseus cluster with Hitomi
astro-ph.HE
We present results of a search for unidentified line emission and absorption
signals in the 2-12keV energy band of spectra extracted from Perseus Cluster
core region observations obtained with the 5eV energy resolution Hitomi Soft
X-ray Spectrometer. No significant unidentified line emission or absorption is
found. Line flux upper limits (1 sigma per resolution element) vary with photon
energy and assumed intrinsic width, decreasing from 100 photons cm$^{-2}$
s$^{-1}$ sr $^{-1}$ at 2keV to $<10$ cm$^{-2}$ s$^{-1}$ sr $^{-1}$ over most of
the 5-10 keV energy range for a Gaussian line with Doppler broadening of 640
km/s. Limits for narrower and broader lines have a similar energy dependence
and are systematically smaller and larger, respectively. These line flux limits
are used to constrain the decay rate of hypothetical dark matter candidates.
For the sterile neutrino decay rate, new constraints over the the mass range of
4-24 keV with mass resolution better than any previous X-ray analysis are
obtained. Additionally, the accuracy of relevant thermal spectral models and
atomic data are evaluated. The Perseus cluster spectra may be described by a
composite of multi-temperature thermal and AGN power-law continua. Superposed
on these, a few line emission signals possibly originating from unmodeled
atomic processes (including Si XIV and Fe XXV) are marginally detected and
tabulated. Comparisons with previous X-ray upper limits and future prospects
for dark matter searches using high-energy resolution spectroscopy are
discussed.
| arxiv topic:astro-ph.HE |
arxiv_dataset-105051811.05867 | Fermionic quantum carpets: From canals and ridges to solitonlike
structures
quant-ph cond-mat.quant-gas
We report a formation of sharp, solitonlike structures in an experimentally
accessible ultracold Fermi gas, as a quantum carpet solution is analyzed in a
many body system. The effect is perfectly coherent in a noninteracting gas, but
in the presence of repulsive interaction in a two-component system, the
structures vanish at a finite time. As they disappear, the system enters a
dynamical equilibrium, in which kinetic energies of atoms tend to the same
average value. The coherence is revived in a strong interaction regime, with
the onset of phase separation, and with a double quantum carpet appearing.
| arxiv topic:quant-ph cond-mat.quant-gas |
arxiv_dataset-105061811.05967 | No-Frills Human-Object Interaction Detection: Factorization, Layout
Encodings, and Training Techniques
cs.CV
We show that for human-object interaction detection a relatively simple
factorized model with appearance and layout encodings constructed from
pre-trained object detectors outperforms more sophisticated approaches. Our
model includes factors for detection scores, human and object appearance, and
coarse (box-pair configuration) and optionally fine-grained layout (human
pose). We also develop training techniques that improve learning efficiency by:
(1) eliminating a train-inference mismatch; (2) rejecting easy negatives during
mini-batch training; and (3) using a ratio of negatives to positives that is
two orders of magnitude larger than existing approaches. We conduct a thorough
ablation study to understand the importance of different factors and training
techniques using the challenging HICO-Det dataset.
| arxiv topic:cs.CV |
arxiv_dataset-105071811.06067 | Interpretable deep learning for guided structure-property explorations
in photovoltaics
cs.LG cs.CV stat.ML
The performance of an organic photovoltaic device is intricately connected to
its active layer morphology. This connection between the active layer and
device performance is very expensive to evaluate, either experimentally or
computationally. Hence, designing morphologies to achieve higher performances
is non-trivial and often intractable. To solve this, we first introduce a deep
convolutional neural network (CNN) architecture that can serve as a fast and
robust surrogate for the complex structure-property map. Several tests were
performed to gain trust in this trained model. Then, we utilize this fast
framework to perform robust microstructural design to enhance device
performance.
| arxiv topic:cs.LG cs.CV stat.ML |
arxiv_dataset-105081811.06167 | Simulating Z_2 topological insulators via a one-dimensional cavity
optomechanical cells array
quant-ph
We propose a novel scheme to simulate Z_2 topological insulators via
one-dimensional (1D) cavity optomechanical cells array. The direct mapping
between 1D cavity optomechanical cells array and 2D quantum spin Hall (QSH)
system can be achieved by using diagonalization and dimensional reduction
methods. We show that the topological features of the present model can be
captured using a 1D generalized Harper equation with an additional SU(2) guage
structure. Interestingly, spin pumping of effective photon-phonon bosons can be
naturally derived after scanning the additional periodic parameter, which means
that we can realize the transition between different QSH edge states.
| arxiv topic:quant-ph |
arxiv_dataset-105091811.06267 | Observers with constant proper acceleration, constant proper jerk, and
beyond
gr-qc
We discuss in Minkowski spacetime the differences between the concepts of
constant proper $n$-acceleration and of vanishing $(n+1)$-acceleration. By
$n$-acceleration we essentially mean the higher order time derivatives of the
position vector of the trajectory of a point particle, adapted to Minkowski
spacetime or eventually to curved spacetime. The $2$-acceleration is known as
the Jerk, the $3$-acceleration as the Snap, etc. As for the concept of {\sl
proper} $n$-acceleration we give a specific definition involving the
instantaneous comoving frame of the observer and we discuss, in such framework,
the difficulties in finding a characterization of this notion as a Lorentz
invariant statement. We show how the Frenet-Serret formalism helps to address
the problem. In particular we find that our definition of an observer with
constant proper acceleration corresponds to the vanishing of the third
curvature invariant $\kappa_3$ (thus the motion is three dimensional in
Minkowski spacetime) together with the constancy of the first and second
curvature invariants and the restriction $\kappa_2 < \kappa_1$, the particular
case $\kappa_2=0$ being the one commonly referred to in the literature. We
generalize these concepts to curved spacetime, in which the notion of
trajectory in a plane is replaced by the vanishing of the second curvature
invariant $\kappa_2$. Under this condition, the concept of constant proper
$n$-acceleration coincides with that of the vanising of the
$(n+1)$-acceleration and is characterized by the fact that the first curvature
invariant $\kappa_1$ is a $(n-1)$-degree polynomial of proper time. We
illustrate some of our results with examples in Minkowski, de Sitter and
Schwarzschild spacetimes.
| arxiv topic:gr-qc |
arxiv_dataset-105101811.06367 | Enhancing Operation of a Sewage Pumping Station for Inter Catchment
Wastewater Transfer by Using Deep Learning and Hydraulic Model
cs.CY cs.LG stat.ML
This paper presents a novel Inter Catchment Wastewater Transfer (ICWT) method
for mitigating sewer overflow. The ICWT aims at balancing the spatial mismatch
of sewer flow and treatment capacity of Wastewater Treatment Plant (WWTP),
through collaborative operation of sewer system facilities. Using a hydraulic
model, the effectiveness of ICWT is investigated in a sewer system in Drammen,
Norway. Concerning the whole system performance, we found that the S{\o}ren
Lemmich pump station plays a vital role in the ICWT framework. To enhance the
operation of this pump station, it is imperative to construct a multi-step
ahead water level prediction model. Hence, one of the most promising artificial
intelligence techniques, Long Short Term Memory (LSTM), is employed to
undertake this task. Experiments demonstrated that LSTM is superior to Gated
Recurrent Unit (GRU), Recurrent Neural Network (RNN), Feed-forward Neural
Network (FFNN) and Support Vector Regression (SVR).
| arxiv topic:cs.CY cs.LG stat.ML |
arxiv_dataset-105111811.06467 | Superconductivity in systems exhibiting the Altshuler-Aronov anomaly
cond-mat.supr-con
Making use of generalized Eliashberg equations, we describe the
Altshuler-Aronov (AA) effect and superconductivity on equal footing. We derive
explicit expressions for the Coulomb pseudopotential in 3D, taking into account
also the anomalous diffusion. We present a full numerical solution for two
normal-state and two anomalous self-energies. In the normal state, we amend the
known results for the purely electronic AA effect; with electron-phonon
coupling turned on, we find additional anomalies in the density of states close
to the phonon energy. We study how the critical temperature and density of
states of strongly disordered 3D superconductors change with normal-state
resistivity. We find that the type of transition from the superconducting to
the insulating state depends on the strength of electron-phonon coupling: at
weak coupling there exists an intermediate normal state, whereas at strong
coupling the transition is direct.
| arxiv topic:cond-mat.supr-con |
arxiv_dataset-105121811.06567 | Automatic Text Document Summarization using Semantic-based Analysis
cs.IR cs.CL
Since the advent of the web, the amount of data on wen has been increased
several million folds. In recent years web data generated is more than data
stored for years. One important data format is text. To answer user queries
over the internet, and to overcome the problem of information overload one
possible solution is text document summarization. This not only reduces query
access time, but also optimize the document results according to specific users
requirements. Summarization of text document can be categorized as abstractive
and extractive. Most of the work has been done in the direction of Extractive
summarization. Extractive summarized result is a subset of original documents
with the objective of more content coverage and lea redundancy. Our work is
based on Extractive approaches. In the first approach, we are using some
statistical features and semantic-based features. To include sentiment as a
feature is an idea cached from a view that emotion plays an important role. It
effectively conveys a message. So, it may play a vital role in text document
summarization.
| arxiv topic:cs.IR cs.CL |
arxiv_dataset-105131811.06667 | Evolutionary Game for Consensus Provision in Permissionless Blockchain
Networks with Shard
cs.GT cs.CR cs.DC
With the development of decentralized consensus protocols, permissionless
blockchains have been envisioned as a promising enabler for the general-purpose
transaction-driven, autonomous systems. However, most of the prevalent
blockchain networks are built upon the consensus protocols under the
crypto-puzzle framework known as proof-of-work. Such protocols face the
inherent problem of transaction-processing bottleneck, as the networks achieve
the decentralized consensus for transaction confirmation at the cost of very
high latency. In this paper, we study the problem of consensus formation in a
system of multiple throughput-scalable blockchains with sharded consensus.
Specifically, the protocol design of sharded consensus not only enables
parallelizing the process of transaction validation with sub-groups of
processors, but also introduces the Byzantine consensus protocols for
accelerating the consensus processes. By allowing different blockchains to
impose different levels of processing fees and to have different
transaction-generating rate, we aim to simulate the multi-service provision
eco-systems based on blockchains in real world. We focus on the dynamics of
blockchain-selection in the condition of a large population of consensus
processors. Hence, we model the evolution of blockchain selection by the
individual processors as an evolutionary game. Both the theoretical and the
numerical analysis are provided regarding the evolutionary equilibria and the
stability of the processors' strategies in a general case.
| arxiv topic:cs.GT cs.CR cs.DC |
arxiv_dataset-105141811.06767 | Planar Hall effect in the Dirac semimetal PdTe2
cond-mat.mtrl-sci cond-mat.mes-hall
We report the synthesis and magneto-transport measurements on the single
crystal of Dirac semimetal PdTe$_2$. The de Haas-van Alphen oscillations with
multiple frequencies have been clearly observed, from which the small effective
masses and nontrivial Berry phase are extracted, implying the possible
existence of the Dirac fermions in PdTe$_2$. The planar Hall effect and
anisotropic longitudinal resistivity originating from the chiral anomaly and
nontrivial Berry phase are observed, providing strong evidence for the
nontrivial properties in PdTe$_2$. With the increase of temperature up to 150
K, planar Hall effect still remains. The possible origin of mismatch between
experimental results and theoretical predictions is also discussed.
| arxiv topic:cond-mat.mtrl-sci cond-mat.mes-hall |
arxiv_dataset-105151811.06867 | Lattice Boltzmann Method simulations of high Reynolds number flows past
porous obstacles
physics.flu-dyn
Lattice Boltzmann Method (LBM) simulations for turbulent flows over a fractal
and non-fractal obstacles are presented. The wake hydrodynamics are compared
and discussed in terms of flow relaxation, Strouhal numbers and wake length for
different Reynolds numbers. Three obstacle topologies are studied, Solid (SS),
Porous Regular (PR) and Porous Fractal (FR). In particular we observe that the
oscillation present in the case of the solid square can be annihilated or only
pushed downstream depending on the topology ot the porous obstacle.
The Lattice Boltzmann Method (LBM) is implemented over a range of four
Reynolds numbers from 12352 to 49410. The suitability of LBM for these high
Reynolds number cases is studied. Its results are compared to available
experimental data and published literature. Compelling agreements between all
three tested obstacles show a significant validation of LBM as a tool to
investigate high Reynolds number flows in complex geometries. This is
particularly important as the LBM method is much less time consuming than a
classical Navier-Stokes equation based computing method and high Reynolds
numbers need to be achieved with enough details (i.e. resolution) to predict
for example canopy flows.
| arxiv topic:physics.flu-dyn |
arxiv_dataset-105161811.06967 | Adaptive Thouless--Anderson--Palmer equation for higher-order Markov
random fields
cond-mat.dis-nn cond-mat.stat-mech
The adaptive Thouless--Anderson--Palmer (TAP) mean-field approximation is one
of the advanced mean-field approaches, and it is known as a powerful accurate
method for Markov random fields (MRFs) with quadratic interactions (pairwise
MRFs). In this study, an extension of the adaptive TAP approximation for MRFs
with many-body interactions (higher-order MRFs) is developed. We show that the
adaptive TAP equation for pairwise MRFs is derived by naive mean-field
approximation with diagonal consistency. Based on the equivalence of the
approximate equation obtained from the naive mean-field approximation with
diagonal consistency and the adaptive TAP equation in pairwise MRFs, we
formulate approximate equations for higher-order Boltzmann machines, which is
one of simplest higher-order MRFs, via the naive mean-field approximation with
diagonal consistency.
| arxiv topic:cond-mat.dis-nn cond-mat.stat-mech |
arxiv_dataset-105171811.07067 | Oscillation theory and semibounded canonical systems
math.SP
Oscillation theory locates the spectrum of a differential equation by
counting the zeros of its solutions. We present a version of this theory for
canonical systems $Ju'=-zHu$ and then use it to discuss semibounded operators
from this point of view. Our main new result is a characterization of systems
with purely discrete spectrum in terms of the asymptotics of their coefficient
functions; we also discuss the exponential types of the transfer matrices.
| arxiv topic:math.SP |
arxiv_dataset-105181811.07167 | Central extensions of free periodic groups
math.GR
It is proved that any countable abelian group $D$ can be embedded as a centre
into a $m$-generated group $A$ such that the quotient group $A/D$ is isomorphic
to the free Burnside group $B(m,n)$ of rank $m>1$ and of odd period $n\ge665$.
The proof is based on some modification of the method which was used by
S.I.Adian in his monograph in 1975 for a positive solution of Kontorovich's
famous problem from Kourovka Notebook on the existence of a finitely generated
non-commutative analogue of the additive group of rational numbers. More
precisely, he proved that the desired analogues in which the intersection of
any two non-trivial subgroups is infinite, can be constructed as a central
extension of the free Burnside group $ B (m, n) $, where $ m> 1 $, and $ n
\ge665 $ is an odd number, using as its center the infinite cyclic group. The
paper also discusses other applications of the proposed generalization of
Adian's technique. In particular, we describe the free groups of the variety
defined by the identity $[x^n,y]=1$ and the Schur multipliers of the free
Burnside groups $B(m,n)$ for any odd $n\ge665$.
| arxiv topic:math.GR |
arxiv_dataset-105191811.07267 | Probabilistic Graphs for Sensor Data-driven Modelling of Power Systems
at Scale
stat.ML cs.LG
The growing complexity of the power grid, driven by increasing share of
distributed energy resources and by massive deployment of intelligent
internet-connected devices, requires new modelling tools for planning and
operation. Physics-based state estimation models currently used for data
filtering, prediction and anomaly detection are hard to maintain and adapt to
the ever-changing complex dynamics of the power system. A data-driven approach
based on probabilistic graphs is proposed, where custom non-linear, localised
models of the joint density of subset of system variables can be combined to
model arbitrarily large and complex systems. The graphical model allows to
naturally embed domain knowledge in the form of variables dependency structure
or local quantitative relationships. A specific instance where neural-network
models are used to represent the local joint densities is proposed, although
the methodology generalises to other model classes. Accuracy and scalability
are evaluated on a large-scale data set representative of the European
transmission grid.
| arxiv topic:stat.ML cs.LG |
arxiv_dataset-105201811.07367 | slimIoT: Scalable Lightweight Attestation Protocol For the Internet of
Things
cs.CR
The Internet of Things (IoT) is increasingly intertwined with critical
industrial processes, yet contemporary IoT devices offer limited security
features, creating a large new attack surface. Remote attestation is a
well-known technique to detect cyber threats by remotely verifying the internal
state of a networked embedded device through a trusted entity. Multi-device
attestation has received little attention although current single-device
approaches show limited scalability in IoT applications. Though recent work has
yielded some proposals for scalable attestation, several aspects remain
unexplored, and thus more research is required. This paper presents slimIoT, a
scalable lightweight attestation protocol that is suitable for all IoT devices.
slimIoT depends on an efficient broadcast authentication scheme along with
symmetric key cryptography. It is resilient against a strong adversary with
physical access to the IoT device. Our protocol is informative in the sense
that it identifies the precise status of every device in the network. We
implement and evaluate slimIoT considering many factors. On the one hand, our
evaluation results show a low overhead in terms of memory footprint and
runtime. On the other hand, simulations demonstrate that slimIoT is scalable,
robust and highly efficient to be used in static and dynamic networks
consisting of thousands of heterogenous IoT devices.
| arxiv topic:cs.CR |
arxiv_dataset-105211811.07467 | Electronic structure of the novel high-$T_{\rm C}$ ferromagnetic
semiconductor (Ga,Fe)Sb: x-ray magnetic circular dichroism and resonance
photoemission spectroscopy studies
cond-mat.str-el
The electronic structure and the magnetism of the novel ferromagnetic
semiconductor (Ga,Fe)Sb, whose Curie temperature $T_{\rm C}$ can exceed room
temperature, were investigated by means of x-ray absorption spectroscopy (XAS),
x-ray magnetic circular dichroism (XMCD), and resonance photoemission
spectroscopy (RPES). The line-shape analyses of the XAS and XMCD spectra
suggest that the ferromagnetism is of intrinsic origin. The orbital magnetic
moments deduced using XMCD sum rules were found to be large, indicating that
there is a considerable amount of 3$d^{6}$ contribution to the ground state of
Fe. From RPES, we observed a strong dispersive Auger peak and non-dispersive
resonantly enhanced peaks in the valence-band spectra. The latter is a
fingerprint of the correlated nature of Fe 3$d$ electrons, whereas the former
indicates their itinerant nature. It was also found that the Fe 3$d$ states
have finite contribution to the DOS at the Fermi energy. These states
presumably consisting of majority-spin $p$-$d$ hybridized states or
minority-spin $e$ states would be responsible for the ferromagnetic order in
this material.
| arxiv topic:cond-mat.str-el |
arxiv_dataset-105221811.07567 | Fine-grained Classification using Heterogeneous Web Data and Auxiliary
Categories
cs.CV
Fine-grained classification remains a very challenging problem, because of
the absence of well-labeled training data caused by the high cost of annotating
a large number of fine-grained categories. In the extreme case, given a set of
test categories without any well-labeled training data, the majority of
existing works can be grouped into the following two research directions: 1)
crawl noisy labeled web data for the test categories as training data, which is
dubbed as webly supervised learning; 2) transfer the knowledge from auxiliary
categories with well-labeled training data to the test categories, which
corresponds to zero-shot learning setting. Nevertheless, the above two research
directions still have critical issues to be addressed. For the first direction,
web data have noisy labels and considerably different data distribution from
test data. For the second direction, zero-shot learning is struggling to
achieve compelling results compared with conventional supervised learning. The
issues of the above two directions motivate us to develop a novel approach
which can jointly exploit both noisy web training data from test categories and
well-labeled training data from auxiliary categories. In particular, on one
hand, we crawl web data for test categories as noisy training data. On the
other hand, we transfer the knowledge from auxiliary categories with
well-labeled training data to test categories by virtue of free semantic
information (e.g., word vector) of all categories. Moreover, given the fact
that web data are generally associated with additional textual information
(e.g., title and tag), we extend our method by using the surrounding textual
information of web data as privileged information. Extensive experiments show
the effectiveness of our proposed methods.
| arxiv topic:cs.CV |
arxiv_dataset-105231811.07667 | Second order linear evolution equations with general dissipation
math.AP
The contraction semigroup $S(t)={\rm e}^{t\mathbb{A}}$ generated by the
abstract linear dissipative evolution equation $$ \ddot u + A u + f(A) \dot u=0
$$ is analyzed, where $A$ is a strictly positive selfadjoint operator and $f$
is an arbitrary nonnegative continuous function on the spectrum of $A$. A full
description of the spectrum of the infinitesimal generator $\mathbb{A}$ of
$S(t)$ is provided. Necessary and sufficient conditions for the stability, the
semiuniform stability and the exponential stability of the semigroup are found,
depending on the behavior of $f$ and the spectral properties of its zero-set.
Applications to wave, beam and plate equations with fractional damping are also
discussed.
| arxiv topic:math.AP |
arxiv_dataset-105241811.07767 | Injecting and removing malignant features in mammography with CycleGAN:
Investigation of an automated adversarial attack using neural networks
cs.CV
$\textbf{Purpose}$ To train a cycle-consistent generative adversarial network
(CycleGAN) on mammographic data to inject or remove features of malignancy, and
to determine whether these AI-mediated attacks can be detected by radiologists.
$\textbf{Material and Methods}$ From the two publicly available datasets, BCDR
and INbreast, we selected images from cancer patients and healthy controls. An
internal dataset served as test data, withheld during training. We ran two
experiments training CycleGAN on low and higher resolution images ($256 \times
256$ px and $512 \times 408$ px). Three radiologists read the images and rated
the likelihood of malignancy on a scale from 1-5 and the likelihood of the
image being manipulated. The readout was evaluated by ROC analysis (Area under
the ROC curve = AUC). $\textbf{Results}$ At the lower resolution, only one
radiologist exhibited markedly lower detection of cancer (AUC=0.85 vs 0.63,
p=0.06), while the other two were unaffected (0.67 vs. 0.69 and 0.75 vs. 0.77,
p=0.55). Only one radiologist could discriminate between original and modified
images slightly better than guessing/chance (0.66, p=0.008). At the higher
resolution, all radiologists showed significantly lower detection rate of
cancer in the modified images (0.77-0.84 vs. 0.59-0.69, p=0.008), however, they
were now able to reliably detect modified images due to better visibility of
artifacts (0.92, 0.92 and 0.97). $\textbf{Conclusion}$ A CycleGAN can
implicitly learn malignant features and inject or remove them so that a
substantial proportion of small mammographic images would consequently be
misdiagnosed. At higher resolutions, however, the method is currently limited
and has a clear trade-off between manipulation of images and introduction of
artifacts.
| arxiv topic:cs.CV |
arxiv_dataset-105251811.07867 | Prediction-Based Decisions and Fairness: A Catalogue of Choices,
Assumptions, and Definitions
stat.AP
A recent flurry of research activity has attempted to quantitatively define
"fairness" for decisions based on statistical and machine learning (ML)
predictions. The rapid growth of this new field has led to wildly inconsistent
terminology and notation, presenting a serious challenge for cataloguing and
comparing definitions. This paper attempts to bring much-needed order.
First, we explicate the various choices and assumptions made---often
implicitly---to justify the use of prediction-based decisions. Next, we show
how such choices and assumptions can raise concerns about fairness and we
present a notationally consistent catalogue of fairness definitions from the ML
literature. In doing so, we offer a concise reference for thinking through the
choices, assumptions, and fairness considerations of prediction-based decision
systems.
| arxiv topic:stat.AP |
arxiv_dataset-105261811.07967 | Hypergeometric function and Modular Curvature II. Connes-Moscovici
functional relation after Lesch's work
math-ph math.DG math.FA math.MP math.QA
As the second part of the sequel, we investigate the variation of
rearrangement operators (more precisely, the spectral functions behind) arising
in the study of modular geometry on noncommutative (two) tori. We initiate a
systematic approach by introducing transformations corresponding to basic
operations in calculus, like differentiation and integration by parts. As for
applications, we extend, in a uniform way, the Connes-Moscovici's functional
relations on noncommutative two tori attached to the variation of second heat
coefficients to noncommutative tori of arbitrary dimension. Moreover, those
transformations lead to more internal relations among the hypergeometric family
obtained in part I of the sequel, which allows us to obtain, the first time, a
computer-aid free verification of those Connes-Moscovici type functional
relations.
| arxiv topic:math-ph math.DG math.FA math.MP math.QA |
arxiv_dataset-105271811.08067 | Reinforcement Learning of Active Vision for Manipulating Objects under
Occlusions
cs.RO cs.CV cs.LG
We consider artificial agents that learn to jointly control their gripperand
camera in order to reinforcement learn manipulation policies in the presenceof
occlusions from distractor objects. Distractors often occlude the object of
in-terest and cause it to disappear from the field of view. We propose hand/eye
con-trollers that learn to move the camera to keep the object within the field
of viewand visible, in coordination to manipulating it to achieve the desired
goal, e.g.,pushing it to a target location. We incorporate structural biases of
object-centricattention within our actor-critic architectures, which our
experiments suggest tobe a key for good performance. Our results further
highlight the importance ofcurriculum with regards to environment difficulty.
The resulting active vision /manipulation policies outperform static camera
setups for a variety of clutteredenvironments.
| arxiv topic:cs.RO cs.CV cs.LG |
arxiv_dataset-105281811.08167 | Bayesian Inference for Structural Vector Autoregressions Identified by
Markov-Switching Heteroskedasticity
econ.EM
In this study, Bayesian inference is developed for structural vector
autoregressive models in which the structural parameters are identified via
Markov-switching heteroskedasticity. In such a model, restrictions that are
just-identifying in the homoskedastic case, become over-identifying and can be
tested. A set of parametric restrictions is derived under which the structural
matrix is globally or partially identified and a Savage-Dickey density ratio is
used to assess the validity of the identification conditions. The latter is
facilitated by analytical derivations that make the computations fast and
numerical standard errors small. As an empirical example, monetary models are
compared using heteroskedasticity as an additional device for identification.
The empirical results support models with money in the interest rate reaction
function.
| arxiv topic:econ.EM |
arxiv_dataset-105291811.08267 | Better than a lens -- Increasing the signal-to-noise ratio through pupil
splitting
physics.optics
Lenses are designed to fulfill Fermats principle such that all light
interferes constructively in its focus, guaranteeing its maximum concentration.
It can be shown that imaging via an unmodified full pupil yields the maximum
transfer strength for all spatial frequencies transferable by the system.
Seemingly also the signal-to-noise ratio (SNR) is optimal. The achievable SNR
at a given photon budget is critical especially if that budget is strictly
limited as in the case of fluorescence microscopy. In this work we propose a
general method which achieves a better SNR for high spatial frequency
information of an optical imaging system, without the need to capture more
photons. This is achieved by splitting the pupil of an incoherent imaging
system such that two (or more) sub-images are simultaneously acquired and
computationally recombined. We compare the theoretical performance of split
pupil imaging to the non-split scenario and implement the splitting using a
tilted elliptical mirror placed at the back-focal-plane (BFP) of a fluorescence
widefield microscope.
| arxiv topic:physics.optics |
arxiv_dataset-105301811.08367 | On the convergence of Ces\'aro means of negative order of
Vilenkin-Fourier series
math.CA
In 1971 Onnewer and Waterman establish sufficient condition which guarantees
uniform convergence of Vilenkin-Fourier series of continuous function. In the
paper we consider different classes of functions of generalized bounded
oscilation and in the terms of these classes there are established sufficient
conditions for uniform convergence of Ces\'aro means of negative order.
| arxiv topic:math.CA |
arxiv_dataset-105311811.08467 | Schur's Lemma for Coupled Reducibility and Coupled Normality
math.RA
Let $\mathcal A = \{A_{ij} \}_{i, j \in \mathcal I}$, where $\mathcal I$ is
an index set, be a doubly indexed family of matrices, where $A_{ij}$ is $n_i
\times n_j$. For each $i \in \mathcal I$, let $\mathcal V_i$ be an
$n_i$-dimensional vector space. We say $\mathcal A$ is reducible in the coupled
sense if there exist subspaces, $\mathcal U_i \subseteq \mathcal V_i$, with
$\mathcal U_i \neq \{0\}$ for at least one $i \in \mathcal I$, and $\mathcal
U_i \neq \mathcal V_i$ for at least one $i$, such that $A_{ij} (\mathcal U_j)
\subseteq \mathcal U_i$ for all $i, j$. Let $\mathcal B = \{B_{ij} \}_{i, j \in
\mathcal I}$ also be a doubly indexed family of matrices, where $B_{ij}$ is
$m_i \times m_j$. For each $i \in \mathcal I$, let $X_i$ be a matrix of size
$n_i \times m_i$. Suppose $A_{ij} X_j = X_i B_{ij}$ for all~$i, j$. We prove
versions of Schur's Lemma for $\mathcal A, \mathcal B$ satisfying coupled
irreducibility conditions. We also consider a refinement of Schur's Lemma for
sets of normal matrices and prove corresponding versions for $\mathcal A,
\mathcal B$ satisfying coupled normality and coupled irreducibility conditions.
| arxiv topic:math.RA |
arxiv_dataset-105321811.08567 | Feasibility analysis of ensemble sensitivity computation in turbulent
flows
physics.comp-ph math.DS
In chaotic systems, such as turbulent flows, the solutions to tangent and
adjoint equations exhibit an unbounded growth in their norms. This behavior
renders the instantaneous tangent and adjoint solutions unusable for
sensitivity analysis. The Lea-Allen-Haine ensemble sensitivity (ES) estimates
provide a way of computing meaningful sensitivities in chaotic systems by
utilizing tangent/adjoint solutions over short trajectories. In this paper, we
analyze the feasibility of ES computations under optimistic mathematical
assumptions on the flow dynamics. Furthermore, we estimate upper bounds on the
rate of convergence of the ES method in numerical simulations of turbulent
flow. Even at the optimistic upper bound, the ES method is computationally
intractable in each of the numerical examples considered.
| arxiv topic:physics.comp-ph math.DS |
arxiv_dataset-105331811.08667 | A linear programming approach to Markov reward error bounds for queueing
networks
math.PR
In this paper, we present a numerical framework for constructing bounds on
stationary performance measures of random walks in the positive orthant using
the Markov reward approach. These bounds are established in terms of stationary
performance measures of a perturbed random walk whose stationary distribution
is known explicitly. We consider random walks in an arbitrary number of
dimensions and with a transition probability structure that is defined on an
arbitrary partition of the positive orthant. Within each component of this
partition the transition probabilities are homogeneous. This enables us to
model queueing networks with, for instance, break-downs and finite buffers. The
main contribution of this paper is that we generalize the linear programming
approach of [1] to this class of models.
| arxiv topic:math.PR |
arxiv_dataset-105341811.08767 | Quantum correlation enhanced weak field detection in optomechanical
system
quant-ph
We propose a theoretical scheme to enhance the signal-to-noise ratio in
ultrasensitive detection with the help of quantum correlation. By introducing
the auxiliary oscillator and treated as an added probe for weak field
detection, the additional noise can be greatly suppressed and the measurement
accuracy may even break the standard quantum limit. We use the magnetic field
as an example to exhibit the detection capability of our scheme. The result
show that, comparing with the traditional detection protocol, our scheme can
have higher signal-to-noise ratio and better detection accuracy. Furthermore,
the signal intensity detection curve shows a good linearity. Our results
provide a promising platform for reducing the additional noise by utilizing
quantum correlation in ultrasensitive detection.
| arxiv topic:quant-ph |
arxiv_dataset-105351811.08867 | Beneficial influence of Hf and Zr additions to Nb4at.%Ta on the vortex
pinning of Nb$_{3}$Sn with and without an O source
cond-mat.supr-con
Here we show that addition of Hf to Nb4Ta can significantly improve the high
field performance of Nb$_{3}$Sn, making it suitable for dipole magnets for
Future Circular Collider (FCC). A big challenge for the FCC is that a realistic
production target for FCC Nb3Sn requires ~30% improvement over current
conductor performance. Recent success with internal oxidation(IO) of Nb-Zr
precursor has shown significant improvement in the layer J$_{c}$ of Nb$_{3}$Sn
wires, albeit the complication of providing an internal O$_{2}$ diffusion path
and avoiding degradation of irreversibility field($_{irr}$). We compare Zr and
Hf additions to the standard Nb4Ta alloy of maximum H$_{c2}$ and H$_{irr}$.
Nb4Ta rods with 1Zr or 1Hf were made into monofilament wires with and without
SnO$_{2}$ and their properties measured over the entire superconducting range
up to 31 T. We found that group IV alloying of Nb4Ta raises H$_{irr}$, though
adding O$_{2}$ still degrades this slightly. As noted in Nb1Zr studies, the
pinning force density F$_{p}$ is strongly enhanced and its peak value shifted
to higher field by IO. A surprising result of this work is that we found better
properties in Nb4Ta1Hf without SnO$_{2}$, F$_{pmax}$ achieving 2.35 times that
of the standard Nb4Ta alloy, while the oxidized Nb4Ta1Zr alloy achieved 1.54
times that of the Nb4Ta alloy. The highest layer J$_{c}$ (16 T, 4.2 K) of 3700
A/mm$^{2}$ was found in the SnO$_{2}$-free wire made with Nb4Ta1Hf alloy. Using
a standard A15 cross-section fraction of 60% for modern PIT and RRP wires, we
estimated that a non-Cu J$_{c}$ of 2200 A/mm$^{2}$ is obtainable in modern
conductors, well above the 1500A/mm$^{2}$ FCC specification. Moreover, the best
properties were obtained without SnO$_{2}$, the Nb4Ta1Hf alloy appears to open
a straightforward route to enhanced properties in Nb$_{3}$Sn wires.
| arxiv topic:cond-mat.supr-con |
arxiv_dataset-105361811.08967 | fPINNs: Fractional Physics-Informed Neural Networks
physics.comp-ph
Physics-informed neural networks (PINNs) are effective in solving
integer-order partial differential equations (PDEs) based on scattered and
noisy data. PINNs employ standard feedforward neural networks (NNs) with the
PDEs explicitly encoded into the NN using automatic differentiation, while the
sum of the mean-squared PDE-residuals and the mean-squared error in
initial/boundary conditions is minimized with respect to the NN parameters. We
extend PINNs to fractional PINNs (fPINNs) to solve space-time fractional
advection-diffusion equations (fractional ADEs), and we demonstrate their
accuracy and effectiveness in solving multi-dimensional forward and inverse
problems with forcing terms whose values are only known at randomly scattered
spatio-temporal coordinates (black-box forcing terms). A novel element of the
fPINNs is the hybrid approach that we introduce for constructing the residual
in the loss function using both automatic differentiation for the integer-order
operators and numerical discretization for the fractional operators. We
consider 1D time-dependent fractional ADEs and compare white-box (WB) and
black-box (BB) forcing. We observe that for the BB forcing fPINNs outperform
FDM. Subsequently, we consider multi-dimensional time-, space-, and
space-time-fractional ADEs using the directional fractional Laplacian and we
observe relative errors of $10^{-4}$. Finally, we solve several inverse
problems in 1D, 2D, and 3D to identify the fractional orders, diffusion
coefficients, and transport velocities and obtain accurate results even in the
presence of significant noise.
| arxiv topic:physics.comp-ph |
arxiv_dataset-105371811.09067 | Online Collective Animal Movement Activity Recognition
cs.LG stat.ML
Learning the activities of animals is important for the purpose of monitoring
their welfare vis a vis their behaviour with respect to their environment and
conspecifics. While previous works have largely focused on activity recognition
in a single animal, little or no work has been done in learning the collective
behaviour of animals. In this work, we address the problem of recognising the
collective movement activities of a group of sheep in a flock. We present a
discriminative framework that learns to track the positions and velocities of
all the animals in the flock in an online manner whilst estimating their
collective activity. We investigate the performance of two simple deep network
architectures and show that we can learn the collective activities with good
accuracy even when the distribution of the activities is skewed.
| arxiv topic:cs.LG stat.ML |
arxiv_dataset-105381811.09167 | Anticipation: an effective evolutionary strategy for a sub-optimal
population in a cyclic environment
q-bio.PE q-bio.QM
We built a two-state model of an asexually reproducing organism in a periodic
environment endowed with the capability to anticipate an upcoming environmental
change and undergo pre-emptive switching. By virtue of these anticipatory
transitions, the organism oscillates between its two states that is a time
$\theta$ out of sync with the environmental oscillation. We show that an
anticipation-capable organism increases its long-term fitness over an organism
that oscillates in-sync with the environment, provided $\theta$ does not exceed
a threshold. We also show that the long-term fitness is maximized for an
optimal anticipation time that decreases approximately as $1/n$, $n$ being the
number of cell divisions in time $T$. Furthermore, we demonstrate that optimal
"anticipators" outperforms "bet-hedgers" in the range of parameters considered.
For a sub-optimal ensemble of anticipators, anticipation performs better to
bet-hedging only when the variance in anticipation is small compared to the
mean and the rate of pre-emptive transition is high. Taken together, our work
suggests that anticipation increases overall fitness of an organism in a
periodic environment and it is a viable alternative to bet-hedging provided the
error in anticipation is small.
| arxiv topic:q-bio.PE q-bio.QM |
arxiv_dataset-105391811.09267 | The hiphive package for the extraction of high-order force constants by
machine learning
cond-mat.mtrl-sci physics.comp-ph
The efficient extraction of force constants (FCs) is crucial for the analysis
of many thermodynamic materials properties. Approaches based on the systematic
enumeration of finite differences scale poorly with system size and can rarely
extend beyond third order when input data is obtained from first-principles
calculations. Methods based on parameter fitting in the spirit of interatomic
potentials, on the other hand, can extract FC parameters from semi-random
configurations of high information density and advanced regularized regression
methods can recover physical solutions from a limited amount of data. Here, we
present the hiPhive Python package, that enables the construction of force
constant models up to arbitrary order. hiPhive exploits crystal symmetries to
reduce the number of free parameters and then employs advanced machine learning
algorithms to extract the force constants. Depending on the problem at hand
both over and underdetermined systems are handled efficiently. The FCs can be
subsequently analyzed directly and or be used to carry out e.g., molecular
dynamics simulations. The utility of this approach is demonstrated via several
examples including ideal and defective monolayers of MoS$_2$ as well as bulk
nickel.
| arxiv topic:cond-mat.mtrl-sci physics.comp-ph |
arxiv_dataset-105401811.09367 | Shell model results for nuclear $\beta^-$-decay properties of $sd$ shell
nuclei
nucl-th nucl-ex
We evaluate the allowed $\beta^-$-decay properties of nuclei with $Z = 8 -
15$ systematically under the framework of the nuclear shell model with the use
of the valence space Hamiltonians derived from modern $ab~intio$ methods, such
as in-medium similarity renormalization group and coupled-cluster theory. For
comparison we also show results obtained with fitted interaction derived from
the chiral effective field theory and phenomenological USDB interaction. We
have performed calculations for O $\rightarrow$ F, F $\rightarrow$ Ne, Ne
$\rightarrow$ Na, Na $\rightarrow$ Mg, Mg $\rightarrow$ Al, Al $\rightarrow$
Si, Si $\rightarrow$ P and P $\rightarrow$ S transitions. Theoretical results
of $B(GT)$, log$ft$ values and half-lives, are discussed and compared with the
available experimental data.
| arxiv topic:nucl-th nucl-ex |
arxiv_dataset-105411811.09467 | Melting and phase change for laser-shocked iron
physics.plasm-ph
Using the LCLS facility at the SLAC National Accelerator Laboratory, we have
observed X-ray scattering from iron compressed with laser driven shocks to
Earth-core like pressures above 400GPa. The data shows shots where melting is
incomplete and we observe hexagonal close packed (hcp) crystal structure at
shock compressed densities up to 14.0 gcm-3 but no evidence of a
double-hexagonal close packed (dhcp) crystal. The observation of a crystalline
structure at these densities, where shock heating is expected to be in excess
of the equilibrium melt temperature, may indicate superheating of the solid.
These results are important for equation of state modelling at high strain
rates relevant for impact scenarios and laser-driven shock wave experiments.
| arxiv topic:physics.plasm-ph |
arxiv_dataset-105421811.09567 | How does Lipschitz Regularization Influence GAN Training?
cs.CV cs.LG
Despite the success of Lipschitz regularization in stabilizing GAN training,
the exact reason of its effectiveness remains poorly understood. The direct
effect of $K$-Lipschitz regularization is to restrict the $L2$-norm of the
neural network gradient to be smaller than a threshold $K$ (e.g., $K=1$) such
that $\|\nabla f\| \leq K$. In this work, we uncover an even more important
effect of Lipschitz regularization by examining its impact on the loss
function: It degenerates GAN loss functions to almost linear ones by
restricting their domain and interval of attainable gradient values. Our
analysis shows that loss functions are only successful if they are degenerated
to almost linear ones. We also show that loss functions perform poorly if they
are not degenerated and that a wide range of functions can be used as loss
function as long as they are sufficiently degenerated by regularization.
Basically, Lipschitz regularization ensures that all loss functions effectively
work in the same way. Empirically, we verify our proposition on the MNIST,
CIFAR10 and CelebA datasets.
| arxiv topic:cs.CV cs.LG |
arxiv_dataset-105431811.09667 | Interpolatory HDG Method for Parabolic Semilinear PDEs
math.NA
We propose the interpolatory hybridizable discontinuous Galerkin
(Interpolatory HDG) method for a class of scalar parabolic semilinear PDEs. The
Interpolatory HDG method uses an interpolation procedure to efficiently and
accurately approximate the nonlinear term. This procedure avoids the numerical
quadrature typically required for the assembly of the global matrix at each
iteration in each time step, which is a computationally costly component of the
standard HDG method for nonlinear PDEs. Furthermore, the Interpolatory HDG
interpolation procedure yields simple explicit expressions for the nonlinear
term and Jacobian matrix, which leads to a simple unified implementation for a
variety of nonlinear PDEs. For a globally-Lipschitz nonlinearity, we prove that
the Interpolatory HDG method does not result in a reduction of the order of
convergence. We display 2D and 3D numerical experiments to demonstrate the
performance of the method.
| arxiv topic:math.NA |
arxiv_dataset-105441811.09767 | Survey on Secure Search Over Encrypted Data on the Cloud
cs.CR
Cloud computing has become a potential resource for businesses and
individuals to outsource their data to remote but highly accessible servers.
However, potentials of the cloud services have not been fully unleashed due to
users' concerns about security and privacy of their data in the cloud.
User-side encryption techniques can be employed to mitigate the security
concerns. Nonetheless, once the data in encrypted, no processing (e.g.,
searching) can be performed on the outsourced data. Searchable Encryption (SE)
techniques have been widely studied to enable searching on the data while they
are encrypted. These techniques enable various types of search on the encrypted
data and offer different levels of security. In addition, although these
techniques enable different search types and vary in details, they share
similarities in their components and architectures. In this paper, we provide a
comprehensive survey on different secure search techniques; a high-level
architecture for these systems, and an analysis of their performance and
security level.
| arxiv topic:cs.CR |
arxiv_dataset-105451811.09867 | On the asymptotic Dirichlet problem for a class of mean curvature type
partial differential equations
math.DG
We study the Dirichlet problem for the following prescribed mean curvature
PDE $$ \begin{cases} -\operatorname{div}\dfrac{\nabla v}{\sqrt{1+|\nabla
v|^{2}}}=f(x,v) \text{ in }\Omega\\ v=\varphi \text{ on }\partial\Omega.
\end{cases} $$ where $\Omega$ is a domain contained in a complete Riemannian
manifold $M,$ $f:\Omega\times\mathbb{R\rightarrow R}$ is a fixed function and
$\varphi$ is a given continuous function on $\partial\Omega$. This is done in
three parts. In the first one we consider this problem in the most general
form, proving the existence of solutions when $\Omega$ is a bounded
$C^{2,\alpha}$ domain, under suitable conditions on $f$, with no restrictions
on $M$ besides completeness. In the second part we study the asymptotic
Dirichlet problem when $M$ is the hyperbolic space $\mathbb{H}^n$ and $\Omega$
is the whole space. This part uses in an essential way the geometric structure
of $\mathbb{H}^n$ to construct special barriers which resemble the Scherk type
solutions of the minimal surface PDE. In the third part one uses these Scherk
type graphs to prove the non existence of isolated asymptotic boundary
singularities for global solutions of this Dirichlet problem.
| arxiv topic:math.DG |
arxiv_dataset-105461811.09967 | Learning Sound Events From Webly Labeled Data
cs.SD cs.MM eess.AS
In the last couple of years, weakly labeled learning has turned out to be an
exciting approach for audio event detection. In this work, we introduce webly
labeled learning for sound events which aims to remove human supervision
altogether from the learning process. We first develop a method of obtaining
labeled audio data from the web (albeit noisy), in which no manual labeling is
involved. We then describe methods to efficiently learn from these webly
labeled audio recordings. In our proposed system, WeblyNet, two deep neural
networks co-teach each other to robustly learn from webly labeled data, leading
to around 17% relative improvement over the baseline method. The method also
involves transfer learning to obtain efficient representations
| arxiv topic:cs.SD cs.MM eess.AS |
arxiv_dataset-105471811.10067 | Tau-decay determination of the strong coupling
hep-ph hep-ex
We review the current status of the determination of the strong coupling from
tau decay. Using the most recent release of the ALEPH data, a very
comprehensive phenomenological analysis has been performed, exploring all
strategies previously considered in the literature and several complementary
approaches. Once their actual uncertainties are properly assessed, the results
from all adopted methodologies are in excellent agreement, leading to a very
robust and reliable value of the strong coupling, $\alpha_s^{(n_f=3)}(m_\tau^2)
= 0.328\pm 0.013$, which implies $\alpha_s^{(n_f=5)}(M_Z^2) = 0.1197\pm
0.0015$.
| arxiv topic:hep-ph hep-ex |
arxiv_dataset-105481811.10167 | LSICC: A Large Scale Informal Chinese Corpus
cs.CL
Deep learning based natural language processing model is proven powerful, but
need large-scale dataset. Due to the significant gap between the real-world
tasks and existing Chinese corpus, in this paper, we introduce a large-scale
corpus of informal Chinese. This corpus contains around 37 million book reviews
and 50 thousand netizen's comments to the news. We explore the informal words
frequencies of the corpus and show the difference between our corpus and the
existing ones. The corpus can be further used to train deep learning based
natural language processing tasks such as Chinese word segmentation, sentiment
analysis.
| arxiv topic:cs.CL |
arxiv_dataset-105491811.10267 | Euclidean partons?
hep-lat hep-ph
In this talk we reexamine the possibility of evaluating parton distribution
functions from lattice simulations. We show that, while in principle individual
moments can be extracted from lattice data, in all cases the process of
renormalization, hindered by lattice momenta limitation, represents an
obstruction to a direct calculation of the full parton distribution function
from QCD simulations. We discuss the case of the Ji quasi-parton distribution
functions, the possibility of using the reduced Ioffe-time distributions and
the more recent proposal of directly subtracting power divergent mixings in
perturbation theory.
| arxiv topic:hep-lat hep-ph |
arxiv_dataset-105501811.10367 | The R-Process Alliance: Spectroscopic Follow-up of Low-Metallicity Star
Candidates from the Best & Brightest Survey
astro-ph.SR
We present results from an observing campaign to identify low-metallicity
stars in the Best & Brightest Survey. From medium-resolution (R ~ 1, 200 - 2,
000) spectroscopy of 857 candidates, we estimate the stellar atmospheric
parameters (Teff, log g, and [Fe/H]), as well as carbon and alpha-element
abundances. We find that 69% of the observed stars have [Fe/H] <= -1.0, 39%
have [Fe/H] <= -2.0, and 2% have [Fe/H] <= -3.0. There are also 133
carbon-enhanced metal-poor (CEMP) stars in this sample, with 97 CEMP Group I
and 36 CEMP Group II stars identified in the A(C) versus [Fe/H] diagram. A
subset of the confirmed low-metallicity stars were followed-up with
high-resolution spectroscopy, as part of the R-process Alliance, with the goal
of identifying new highly and moderately r-process-enhanced stars. Comparison
between the stellar atmospheric parameters estimated in this work and from
high-resolution spectroscopy exhibit good agreement, confirming our expectation
that medium-resolution observing campaigns are an effective way of selecting
interesting stars for further, more targeted, efforts.
| arxiv topic:astro-ph.SR |
arxiv_dataset-105511811.10467 | Dynamical phase transitions to optomechanical superradiance
quant-ph
We theoretically analyze superradiant emission of light from an ultracold gas
of bosonic atoms confined in a bad cavity. A metastable dipolar transition of
the atoms couples to the cavity field and is incoherently pumped, the
mechanical effects of cavity-atom interactions tend to order the atoms in the
periodic cavity potential. By means of a mean-field model we determine the
conditions on the cavity parameters and pump rate that lead to the buildup of a
stable macroscopic dipole emitting coherent light. We show that this occurs
when the superradiant decay rate and the pump rate exceed threshold values of
the order of the photon recoil energy. Above these thresholds superradiant
emission is accompanied by the formation of stable matter-wave gratings that
diffract the emitted photons. Outside of this regime, instead, the
optomechanical coupling can give rise to dephasing or chaos, for which the
emitted light is respectively incoherent or chaotic. These behaviors exhibit
the features of a dynamical phase transitions and emerge from the interplay
between global optomechanical interactions, quantum fluctuations, and noise.
| arxiv topic:quant-ph |
arxiv_dataset-105521811.10567 | Chromatic numbers of Kneser-type graphs
math.CO
Let $G(n, r, s)$ be a graph whose vertices are all $r$-element subsets of an
$n$-element set, in which two vertices are adjacent if they intersect in
exactly $s$ elements. In this paper we study chromatic numbers of $G(n, r, s)$
with $r, s$ being fixed constants and $n$ tending to infinity. Using a recent
result of Keevash on existence of designs we deduce an inequality $\chi(G(n, r,
s)) \le (1+o(1))n^{r-s} \frac{(r-s-1)!}{(2r-2s-1)!}$ for $r > s$ with $r, s$
fixed constants. This inequality gives sharp upper bounds for $r \le 2s+1$.
Also we develop an elementary approach to this problem and prove that
$\chi(G(n, 4, 2)) \sim \frac{n^2}{6}$ without use of Keevash's results.
Some bounds on the list chromatic number of $G(n, r, s)$ are also obtained.
| arxiv topic:math.CO |
arxiv_dataset-105531811.10667 | Embedding Uncertain Knowledge Graphs
cs.AI cs.CL
Embedding models for deterministic Knowledge Graphs (KG) have been
extensively studied, with the purpose of capturing latent semantic relations
between entities and incorporating the structured knowledge into machine
learning. However, there are many KGs that model uncertain knowledge, which
typically model the inherent uncertainty of relations facts with a confidence
score, and embedding such uncertain knowledge represents an unresolved
challenge. The capturing of uncertain knowledge will benefit many
knowledge-driven applications such as question answering and semantic search by
providing more natural characterization of the knowledge. In this paper, we
propose a novel uncertain KG embedding model UKGE, which aims to preserve both
structural and uncertainty information of relation facts in the embedding
space. Unlike previous models that characterize relation facts with binary
classification techniques, UKGE learns embeddings according to the confidence
scores of uncertain relation facts. To further enhance the precision of UKGE,
we also introduce probabilistic soft logic to infer confidence scores for
unseen relation facts during training. We propose and evaluate two variants of
UKGE based on different learning objectives. Experiments are conducted on three
real-world uncertain KGs via three tasks, i.e. confidence prediction, relation
fact ranking, and relation fact classification. UKGE shows effectiveness in
capturing uncertain knowledge by achieving promising results on these tasks,
and consistently outperforms baselines on these tasks.
| arxiv topic:cs.AI cs.CL |
arxiv_dataset-105541811.10767 | The Batched Set Cover Problem
cs.DS
We introduce the batched set cover problem, which is a generalization of the
online set cover problem. In this problem, the elements of the ground set that
need to be covered arrive in batches. Our main technical contribution is a
tight $\Omega(H_{m - 2^z + 1})$ lower bound on the competitive ratio of any
fractional batched algorithm given an adversary that is required to produce
batches of VC-dimension at least $z$, for some $z \in \mathbb{N}^0$. This
restriction on the adversary is motivated by the fact that, in some real world
applications, decisions are made after collecting batches of data of
non-trivial VC-dimension. In particular, ridesharing systems rely on the batch
assignment of trip requests to vehicles, and some related problems such as that
of optimal congregation points for passenger pickups and dropoffs can be
modeled as a batched set cover problem with VC-dimension greater than or equal
to two. Furthermore, we note that while any online algorithm may be used to
solve the batched set cover problem by artificially sequencing the elements in
a batch, this procedure may neglect the rich information encoded in the complex
interactions between the elements of a batch and the sets that contain them.
Therefore, we propose a minor modification to an online algorithm found in [8]
to obtain an algorithm that attempts to exploit such information.
Unfortunately, we are unable to improve its analysis in a way that reflects
this intuition. However, we present computational experiments that provide
empirical evidence of a constant factor improvement in the competitive ratio.
To the best of our knowledge, we are the first to use the VC-dimension in the
context of online (batched) covering problems.
| arxiv topic:cs.DS |
arxiv_dataset-105551811.10867 | Thermoelectric properties of (Ba,K)Cd2As2 crystallized in the
CaAl2Si2-type structure
cond-mat.mtrl-sci
As-Based Zintl compounds Ba1-xKxCd2As2 crystallized in the CaAl2Si2-type
structure (space group P3-m1) were prepared using solid-state reactions
followed by hot-pressing. We have successfully substituted K for Ba up to x =
0.08, producing hole-carrier doping with concentrations up to 1.60*1020 cm-3.
We have determined the band-gap value of non-doped BaCd2As2 to be 0.40 eV from
the temperature dependence of the electrical resistivity. Both the electrical
resistivity and the Seebeck coefficient decrease with hole doping, leading to a
power factor value of 1.28 mW m-1 K-2 at 762 K for x = 0.04. A first-principles
band calculation shows that the relatively large power factor mainly originates
from the two-fold degeneracy of the bands comprising As px,y orbitals and from
the anisotropic band structure at the valence-band maximum. The lattice thermal
conductivity is suppressed by the K doping to 0.46 W m-1 K-1 at 773 K for x =
0.08, presumably due to randomness. The effect of randomness is compensated by
an increase in the electronic thermal conductivity, which keeps the total
thermal conductivity approximately constant. In consequence, the dimensionless
figure-of-merit ZT reaches a maximum value of 0.81 at 762 K for x = 0.04.
| arxiv topic:cond-mat.mtrl-sci |
arxiv_dataset-105561811.10967 | Saxl Conjecture for triple hooks
math.RT
We make some progresses on Saxl conjecture. Firstly, we show that the
probability that a partition is comparable in dominance order to the staircase
partition tends to zero as the staircase partition grows. Secondly, for
partitions whose Durfee size is $k$ where $k\geq3$, by semigroup property, we
show that there exists a number $n_k$ such that if the tensor squares of the
first $n_k$ staircase partitions contain all irreducible representations
corresponding to partitions with Durfee size $k$, then all tensor squares
contain partitions with Durfee size $k$. Specially, we show that $n_3=14$ and
$n_4=28$. Furthermore, with the help of computer we show that the Saxl
conjecture is true for all triple-hooks (i.e. partitions with Durfee size 3).
Similar results for chopped square and caret shapes are also discussed.
| arxiv topic:math.RT |
arxiv_dataset-105571811.11067 | Learning State Representations in Complex Systems with Multimodal Data
cs.LG cs.AI stat.ML
Representation learning becomes especially important for complex systems with
multimodal data sources such as cameras or sensors. Recent advances in
reinforcement learning and optimal control make it possible to design control
algorithms on these latent representations, but the field still lacks a
large-scale standard dataset for unified comparison. In this work, we present a
large-scale dataset and evaluation framework for representation learning for
the complex task of landing an airplane. We implement and compare several
approaches to representation learning on this dataset in terms of the quality
of simple supervised learning tasks and disentanglement scores. The resulting
representations can be used for further tasks such as anomaly detection,
optimal control, model-based reinforcement learning, and other applications.
| arxiv topic:cs.LG cs.AI stat.ML |
arxiv_dataset-105581811.11167 | Integrated Object Detection and Tracking with Tracklet-Conditioned
Detection
cs.CV
Accurate detection and tracking of objects is vital for effective video
understanding. In previous work, the two tasks have been combined in a way that
tracking is based heavily on detection, but the detection benefits marginally
from the tracking. To increase synergy, we propose to more tightly integrate
the tasks by conditioning the object detection in the current frame on
tracklets computed in prior frames. With this approach, the object detection
results not only have high detection responses, but also improved coherence
with the existing tracklets. This greater coherence leads to estimated object
trajectories that are smoother and more stable than the jittered paths obtained
without tracklet-conditioned detection. Over extensive experiments, this
approach is shown to achieve state-of-the-art performance in terms of both
detection and tracking accuracy, as well as noticeable improvements in tracking
stability.
| arxiv topic:cs.CV |
arxiv_dataset-105591811.11267 | ALMA, ATCA, and Spitzer Observations of the Luminous Extragalactic
Supernova SN 1978K
astro-ph.HE
Only three extragalactic supernovae have been detected at late times at
millimeter wavelengths: SN 1987A, SN 1978K, and SN 1996cr. SN 1978K is a
remarkably luminous Type IIn supernova that remains bright at all wavelengths
40 years after its explosion. Here we present Atacama Large
Millimeter/submillimeter Array (ALMA) observations taken in 2016 using Bands 3,
4, 6, and 7 that show a steepening in the spectrum. An absorbed single power
law model broadly fits all the radio and millimeter observations, but would
require significant chromatic variability. Alternatively, a broken power law
fits the radio-millimeter spectrum: this can be explained using an
ultra-relativistic spherical blast wave in a wind scaling with a cooling break,
as in a gamma-ray burst afterglow. Using updated Australia Telescope Compact
Array (ATCA) light curves, we show the non-thermal radio continuum continues to
decay as $t^{-1.53}$; in the fireball model, this independently defines the
power law indices found in the radio-millimeter spectrum. Supernovae such as SN
1978K might be important contributors to the Universal dust budget: only SN
1978K was detected in a search for warm dust in supernovae in the transitional
phase (age 10-100 years). Using Spitzer Space Telescope observations, we show
that at least some of this dust emission has been decaying rapidly as
$t^{-2.45}$ over the past decade, suggesting it is being destroyed. Depending
on the modeling of the synchrotron emission, the ALMA observations suggest
there may be emission from a cold dust component.
| arxiv topic:astro-ph.HE |
arxiv_dataset-105601811.11367 | Duality Web on a 3D Euclidean Lattice and Manifestation of Hidden
Symmetries
hep-th cond-mat.str-el
We generalize our previous lattice construction of the abelian bosonization
duality in $2+1$ dimensions to the entire web of dualities as well as the
$N_f=2$ self-duality, via the lattice implementation of a set of modular
transformations in the theory space. The microscopic construction provides
explicit operator mappings, and allows the manifestation of some hidden
symmetries. It also exposes certain caveats and implicit assumptions beneath
the usual application of the modular transformations to generate the web of
dualities. Finally, we make brief comments on the non-relativistic limit of the
dualities.
| arxiv topic:hep-th cond-mat.str-el |
arxiv_dataset-105611811.11467 | Characteristic classes of orbit stratifications, the axiomatic approach
math.AG
Consider a complex algebraic group $G$ acting on a smooth variety $M$ with
finitely many orbits, and let $\Omega$ be an orbit. The following three
invariants of $\Omega\subset M$ can be characterized axiomatically: (1) the
equivariant fundamental class $[\overline{\Omega}, M]\in H^*_G(M)$, (2) the
equivariant Chern-Schwartz-MacPherson class $c(\Omega, M)\in H^*_G(M)$, and (3)
the equivariant motivic Chern class $mC(\Omega, M) \in K_G(M)[y]$. The axioms
for Chern-Schwartz-MacPherson and motivic Chern classes are motivated by the
axioms for cohomological and K-theoretic stable envelopes of Okounkov and his
coauthors. For $M$ a flag variety and $\Omega$ a Schubert cell---an orbit of
the Borel group acting---this implies that CSM and MC classes coincide with the
weight functions studied by Rimanyi-Tarasov-Varchenko. In this paper we review
the general theory and illustrate it with examples.
| arxiv topic:math.AG |
arxiv_dataset-105621811.11567 | A Beilinson-Bernstein theorem for twisted arithmetic differential
operators on the formal flag variety
math.RT
Let us suppose that $\mathbb{Q}_p$ is the field of $p$-adic numbers and
$\mathbb{G}$ is a split connected reductive group scheme over $\mathbb{Z}_p$.
In this work we will introduce a sheaf of twisted arithmetic differential
operators on the formal flag variety of $\mathbb{G}$, associated to a general
character. We will generalize the arguments of C. Huyghe and T. Schmidt,
concerning the $\mathcal{D}^{\dag}$-affinity of the formal flag variety of
$\mathbb{G}$, of certain sheaves of $p$-adically complete twisted arithmetic
differential operators associated to an algebraic character, and the
calculation of the global sections.
| arxiv topic:math.RT |
arxiv_dataset-105631811.11667 | The complexity of matrix multiplication: developments since 2014.
Extended abstract of 2018 Oberwolfach Complexity meeting plenary lecture
cs.CC math.AG
This is an overview of recent developments regarding the complexity of matrix
multiplication, with an emphasis on the uses of algebraic geometry and
representation theory in complexity theory.
| arxiv topic:cs.CC math.AG |
arxiv_dataset-105641811.11767 | The MOSDEF Survey: Significant Evolution in the Rest-Frame Optical
Emission Line Equivalent Widths of Star-Forming Galaxies at z=1.4-3.8
astro-ph.GA
We use extensive spectroscopy from the MOSFIRE Deep Evolution Field (MOSDEF)
survey to investigate the relationships between rest-frame optical emission
line equivalent widths ($W$) and a number of galaxy and ISM characteristics for
a sample of $1134$ star-forming galaxies at redshifts $1.4\lesssim z\lesssim
3.8$. We examine how the equivalent widths of [OII]$\lambda\lambda 3727, 3730$,
H$\beta$, [OIII]$\lambda\lambda 4960, 5008$, [OIII]$+$H$\beta$, H$\alpha$, and
H$\alpha$+[NII]$\lambda\lambda 6550, 6585$, depend on stellar mass, UV slope,
age, star-formation rate (SFR) and specific SFR (sSFR), ionization parameter
and excitation conditions (O32 and [OIII]/H$\beta$), gas-phase metallicity, and
ionizing photon production efficiency ($\xi_{\rm ion}$). The trend of
increasing $W$ with decreasing stellar mass is strongest for [OIII] (and
[OIII]+H$\beta$). More generally, the equivalent widths of all the lines
increase with redshift at a fixed stellar mass or fixed gas-phase metallicity,
suggesting that high equivalent width galaxies are common at high redshift.
This redshift evolution in equivalent widths can be explained by the increase
in SFR and decrease in metallicity with redshift at a fixed stellar mass.
Consequently, the dependence of $W$ on sSFR is largely invariant with redshift,
particularly when examined for galaxies of a given metallicity. Our results
show that high equivalent width galaxies, specifically those with high $W({\rm
[OIII]})$, have low stellar masses, blue UV slopes, young ages, high sSFRs, ISM
line ratios indicative of high ionization parameters, high $\xi_{\rm ion}$, and
low metallicities. As these characteristics are often attributed to galaxies
with high ionizing escape fractions, galaxies with high $W$ are likely
candidates for the population that dominates cosmic reionization.
| arxiv topic:astro-ph.GA |
arxiv_dataset-105651811.11867 | Imaging antiferromagnetic antiphase domain boundaries using magnetic
Bragg diffraction phase contrast
cond-mat.mes-hall
Manipulating magnetic domains is essential for many technological
applications. Recent breakthroughs in Antiferromagnetic Spintronics brought up
novel concepts for electronic device development. Imaging antiferromagnetic
domains is of key importance to this field. Unfortunately, some of the basic
domain types, such as antiphase domains, cannot be imaged by conventional
techniques. Herein, we present a new domain projection imaging technique based
on the localization of domain boundaries by resonant magnetic diffraction of
coherent x rays. Contrast arises from reduction of the scattered intensity at
the domain boundaries due to destructive interference effects. We demonstrate
this approach by imaging antiphase domains in a collinear antiferromagnet
Fe2Mo3O8, and observe evidence of domain wall interaction with a structural
defect. This technique does not involve any numerical algorithms. It is fast,
sensitive, produces large-scale images in a single-exposure measurement, and is
applicable to a variety of magnetic domain types.
| arxiv topic:cond-mat.mes-hall |
arxiv_dataset-105661811.11967 | Classical and quantum cosmology of $K$-essentially modified $R^2$ and
pure $R^p$ gravity
gr-qc
We present a gravitational action with a modified higher order term of a
combination of scalar curvature and Lagrangian density of a scalar field. This
type of models has been considered first by Cruz-Dombriz et al. The classical
and quantum cosmologies governed by the modified action are studied. Models
described by a positive-definite action and a pure arbitrary-powered scalar
curvature action without the standard Einstein-Hilbert term are also
investigated. We show some particular cases in which exact solutions can be
obtained.
| arxiv topic:gr-qc |
arxiv_dataset-105671811.12067 | Skyrmion lifetimes in ultrathin films
cond-mat.mes-hall
We show that thermal stability of magnetic skyrmions can be strongly affected
by entropic effects. The lifetimes of isolated skyrmions in atomic Pd/Fe
bilayers on Ir(111) and on Rh(111) are calculated in the framework of harmonic
transition state theory based on an atomistic spin model parametrized from
density functional theory. Depending on the system the attempt frequency for
skyrmion collapse can change by up to nine orders of magnitude with the
strength of the applied magnetic field. We demonstrate that this effect is due
to a drastic change of entropy with skyrmion radius which opens a novel route
towards stabilizing sub-10 nm skyrmions at room temperature.
| arxiv topic:cond-mat.mes-hall |
arxiv_dataset-105681811.12167 | Density Changes in Low Pressure Gas Targets for Electron Scattering
Experiments
physics.ins-det nucl-ex
A system of modular sealed gas target cells has been developed for use in
electron scattering experiments at the Thomas Jefferson National Accelerator
Facility (Jefferson Lab). This system was initially developed to complete the
MARATHON experiment which required, among other species, tritium as a target
material. Thus far, the cells have been loaded with the gas species 3H, 3He,
2H, 1H and 40Ar and operated in nominal beam currents of up to 22.5 uA in
Jefferson Lab's Hall A. While the gas density of the cells at the time of
loading is known, the density of each gas varies uniquely when heated by the
electron beam. To extract experimental cross sections using these cells,
density dependence on beam current of each target fluid must be determined. In
this study, data from measurements with several beam currents within the range
of 2.5 to 22.5 uA on each target fluid are presented. Additionally, expressions
for the beam current dependent fluid density of each target are developed.
| arxiv topic:physics.ins-det nucl-ex |
arxiv_dataset-105691811.12267 | Minimizing rf-induced excess micromotion of a trapped ion with the help
of ultracold atoms
cond-mat.quant-gas physics.atom-ph
We report on the compensation of excess micromotion due to parasitic
rf-electric fields in a Paul trap. The parasitic rf-electric fields stem from
the Paul trap drive but cause excess micromotion, e.g. due to imperfections in
the setup of the Paul trap. We compensate these fields by applying rf-voltages
of the same frequency but adequate phases and amplitudes to Paul trap
electrodes. The magnitude of micromotion is probed by studying elastic
collision rates of the trapped ion with a gas of ultracold neutral atoms.
Furthermore, we demonstrate that also reactive collisions can be used to
quantify micromotion. We achieve compensation efficiencies of about
1$\:\text{Vm}^{-1}$, which is comparable to other conventional methods.
| arxiv topic:cond-mat.quant-gas physics.atom-ph |
arxiv_dataset-105701811.12367 | Quantum Corrections to Central Charges and Supersymmetric Casimir Energy
in AdS$_3$/CFT$_2$
hep-th
We study the Casimir energy of bulk fields in AdS$_3$ and its relation to
subleading terms in the central charge of the dual CFT$_2$. Computing both
sides of the standard CFT$_2$ relation $E=-c/12$ independently we show that
this relation is not necessarily satisfied at the level of individual bulk
supergravity states, but in theories with sufficient supersymmetry it is
restored at the level of bulk supermultiplets. Assuming only $(0,2)$
supersymmetry (or more), we improve the situation by relating quantum
corrections to the central charge and the supersymmetric Casimir energy which
in turn is related to an index. These relations adapt recent progress on the
AdS$_5$/CFT$_4$ correspondence to AdS$_3$/CFT$_2$ holography. We test our
formula successfully in several examples, including the $(0,4)$ MSW theory
describing classes of 4D black holes and the large $(4,4)$ theory that is
interesting for higher spin holography. We also make predictions for the
subleading central charges in several recently proposed $(2,2)$ dualities where
the CFT$_2$ is not yet well-understood.
| arxiv topic:hep-th |
arxiv_dataset-105711811.12467 | Hand Gesture Recognition based on Radar Micro-Doppler Signature
Envelopes
eess.SP
We introduce a simple but effective technique in automatic hand gesture
recognition using radar. The proposed technique classifies hand gestures based
on the envelopes of their micro-Doppler signatures. These envelopes capture the
distinctions among different hand movements and their corresponding positive
and negative Doppler frequencies which are generated during each gesture act.
We detect the positive and negative envelopes separately, and form a feature
vector of their augmentation. We use the $k$-nearest neighbor ($k$NN)
classifier and Manhattan distance (L1) measure, in lieu of Euclidean distance
(L2), so as not to diminish small but critical envelope values. It is shown
that this method outperforms both low-dimension representation techniques based
on principal component analysis (PCA) and sparse reconstruction using
Gaussian-windowed Fourier dictionary, and can achieve very high classification
rates.
| arxiv topic:eess.SP |
arxiv_dataset-105721811.12567 | Stochastic Dynamics for Earthquake Ruptures
physics.geo-ph
In this paper, we propose a stochastic dynamic model for earthquake rupture
and suggest that the Langevin equation of frictions may be used for
interpreting the slip distributions of rupture processes in earthquakes. The
steady-state solution of the derived Langevin equation analytically attains the
truncated exponential (TEX) distribution that is empirically characterized in
many rupture models of earthquake events worldwide, as demonstrated by
Thingbaijam and Mai (2016, https://doi.org/10.1785/0120150291). Our proposed
stochastic dynamic faulting model for earthquake rupture intrinsically includes
fluctuations and uncertainties in the heterogeneity of faulting planes as
random variables. Specifically, we related the characteristic parameter u_c in
TEX functions to the ratio of diffusion and friction coefficients D and \gamma
of the Langevin equation.
| arxiv topic:physics.geo-ph |
arxiv_dataset-105731811.12667 | Improved Crowding Distance for NSGA-II
cs.NE cs.AI
Non-dominated sorting genetic algorithm II (NSGA-II) does well in dealing
with multi-objective problems. When evaluating validity of an algorithm for
multi-objective problems, two kinds of indices are often considered
simultaneously, i.e. the convergence to Pareto Front and the distribution
characteristic. The crowding distance in the standard NSGA-II has the property
that solutions within a cubic have the same crowding distance, which has no
contribution to the convergence of the algorithm. Actually the closer to the
Pareto Front a solution is, the higher priority it should have. In the paper,
the crowding distance is redefined while keeping almost all the advantages of
the original one. Moreover, the speed of converging to the Pareto Front is
faster. Finally, the improvement is proved to be effective by applying it to
solve nine Benchmark problems.
| arxiv topic:cs.NE cs.AI |
arxiv_dataset-105741811.12767 | High-order stroboscopic averaging methods for highly oscillatory delay
problems
math.NA
We introduce and analyze a family of heterogeneous multiscale methods for the
numerical integration of highly oscillatory systems of delay differential
equations with constant delays. The methodology suggested provides algorithms
of arbitrarily high accuracy.
| arxiv topic:math.NA |
arxiv_dataset-105751811.12867 | Normalizers of maximal tori and real forms of Lie groups
math.RT
Given a complex connected reductive Lie group $G$ with a maximal torus
$H\subset G$, Tits defined an extension $W_G^T$ of the corresponding Weyl group
$W_G$. The extended group is supplied with an embedding into the normalizer
$N_G(H)$, such that $W_G^T$ together with $H$ generate $N_G(H)$. In this paper
we propose an interpretation of the Tits classical construction in terms of the
maximal split real form $G(\mathbb{R})\subset G$, which leads to the simple
topological description of $W^T_G$. We also consider a variation of the Tits
construction associated with compact real form $U$ of $G$. In this case we
define an extension $W_G^U$ of the Weyl group $W_G$, naturally embedded into
the group extension $\widetilde{U}:=U\rtimes\Gamma$ of the compact real form
$U$ by the Galois group $\Gamma={\rm
Gal}(\mathbb{C}/\mathbb{R})$. Generators of $W^U_G$ are squared to identity
as in the Weyl group $W_G$. However, the non-trivial action of $\Gamma$ by
outer automorphisms requires $W^U_G$ to be a non-trivial extension of $W_G$.
This gives a specific presentation of the maximal torus normalizer of the group
extension $\widetilde{U}$. Finally, we describe explicitly the adjoint action
of $W_G^T$ and $W^U_G$ on the Lie algebra of $G$.
| arxiv topic:math.RT |
arxiv_dataset-105761812.00026 | Extended Riemannian Geometry III: Global Double Field Theory with
Nilmanifolds
hep-th math-ph math.MP
We describe the global geometry, symmetries and tensors for Double Field
Theory over pairs of nilmanifolds with fluxes or gerbes. This is achieved by a
rather straightforward application of a formalism we developed previously. This
formalism constructs the analogue of a Courant algebroid over the
correspondence space of a T-duality, using the language of graded manifolds,
derived brackets and we use the description of nilmanifolds in terms of
periodicity conditions rather than local patches. The strong section condition
arises purely algebraically, and we show that for a particularly symmetric
solution of this condition, we recover the Courant algebroids of both
nilmanifolds with fluxes. We also discuss the finite, global symmetries of
general local Double Field Theory and explain how this specializes to the case
of T-duality between nilmanifolds.
| arxiv topic:hep-th math-ph math.MP |
arxiv_dataset-105771812.00126 | Simple Confidence Intervals for MCMC Without CLTs
stat.ME math.PR
This short note argues that 95% confidence intervals for MCMC estimates can
be obtained even without establishing a CLT, by multiplying their widths by
2.3.
| arxiv topic:stat.ME math.PR |
arxiv_dataset-105781812.00226 | Leibniz's well-founded fictions and their interpretations
math.HO math.CA math.LO
Leibniz used the term fiction in conjunction with infinitesimals. What kind
of fictions they were exactly is a subject of scholarly dispute. The position
of Bos and Mancosu contrasts with that of Ishiguro and Arthur. Leibniz's own
views, expressed in his published articles and correspondence, led Bos to
distinguish between two methods in Leibniz's work: (A) one exploiting classical
`exhaustion' arguments, and (B) one exploiting inassignable infinitesimals
together with a law of continuity. Of particular interest is evidence stemming
from Leibniz's work Nouveaux Essais sur l'Entendement Humain as well as from
his correspondence with Arnauld, Bignon, Dagincourt, Des Bosses, and Varignon.
A careful examination of the evidence leads us to the opposite conclusion from
Arthur's. We analyze a hitherto unnoticed objection of Rolle's concerning the
lack of justification for extending axioms and operations in geometry and
analysis from the ordinary domain to that of infinitesimal calculus, and
reactions to it by Saurin and Leibniz. A newly released 1705 manuscript by
Leibniz (Puisque des personnes...) currently in the process of digitalisation,
sheds light on the nature of Leibnizian inassignable infinitesimals. In a pair
of 1695 texts Leibniz made it clear that his incomparable magnitudes violate
Euclid's Definition V.4, a.k.a. the Archimedean property, corroborating the
non-Archimedean construal of the Leibnizian calculus.
Keywords: Archimedean property; assignable vs inassignable quantity; Euclid's
Definition V.4; infinitesimal; law of continuity; law of homogeneity; logical
fiction; Nouveaux Essais; pure fiction; quantifier-assisted paraphrase;
syncategorematic; transfer principle; Arnauld; Bignon; Des Bosses; Rolle;
Saurin; Varignon
| arxiv topic:math.HO math.CA math.LO |
arxiv_dataset-105791812.00326 | Comparing optimization strategies for force field parameterization
physics.comp-ph cond-mat.mtrl-sci
Classical molecular dynamics (MD) simulations enable modeling of materials
and examination of microscopic details that are not accessible experimentally.
The predictive capability of MD relies on the force field (FF) used to describe
interatomic interactions. FF parameters are typically determined to reproduce
selected material properties computed from density functional theory (DFT)
and/or measured experimentally. A common practice in parameterizing FFs is to
use least-squares local minimization algorithms. Genetic algorithms (GAs) have
also been demonstrated as a viable global optimization approach, even for
complex FFs. However, an understanding of the relative effectiveness and
efficiency of different optimization techniques for the determination of FF
parameters is still lacking. In this work, we evaluate various FF parameter
optimization schemes, using as example a training data set calculated from DFT
for different polymorphs of Ir$O_2$. The Morse functional form is chosen for
the pairwise interactions and the optimization of the parameters against the
training data is carried out using (1) multi-start local optimization
algorithms: Simplex, Levenberg-Marquardt, and POUNDERS, (2) single-objective
GA, and (3) multi-objective GA. Using random search as a baseline, we compare
the algorithms in terms of reaching the lowest error, and number of function
evaluations. We also compare the effectiveness of different approaches for FF
parameterization using a test data set with known ground truth (i.e generated
from a specific Morse FF). We find that the performance of optimization
approaches differs when using the Test data vs. the DFT data. Overall, this
study provides insight for selecting a suitable optimization method for FF
parameterization, which in turn can enable more accurate prediction of material
properties and chemical phenomena.
| arxiv topic:physics.comp-ph cond-mat.mtrl-sci |
arxiv_dataset-105801812.00426 | GPSfM: Global Projective SFM Using Algebraic Constraints on Multi-View
Fundamental Matrices
cs.CV
This paper addresses the problem of recovering projective camera matrices
from collections of fundamental matrices in multiview settings. We make two
main contributions. First, given ${n \choose 2}$ fundamental matrices computed
for $n$ images, we provide a complete algebraic characterization in the form of
conditions that are both necessary and sufficient to enabling the recovery of
camera matrices. These conditions are based on arranging the fundamental
matrices as blocks in a single matrix, called the $n$-view fundamental matrix,
and characterizing this matrix in terms of the signs of its eigenvalues and
rank structures. Secondly, we propose a concrete algorithm for projective
structure-from-motion that utilizes this characterization. Given a complete or
partial collection of measured fundamental matrices, our method seeks camera
matrices that minimize a global algebraic error for the measured fundamental
matrices. In contrast to existing methods, our optimization, without any
initialization, produces a consistent set of fundamental matrices that
corresponds to a unique set of cameras (up to a choice of projective frame).
Our experiments indicate that our method achieves state of the art performance
in both accuracy and running time.
| arxiv topic:cs.CV |
arxiv_dataset-105811812.00526 | On the Geometry of Curvature Radiation and Implications for Subpulse
Drifting
astro-ph.HE
The phenomenon of subpulse drifting offers unique insights into the emission
geometry of pulsars, and is commonly interpreted in terms of a rotating
carousel of "spark" events near the stellar surface. We develop a detailed
geometric model for the emission columns above a carousel of sparks that is
entirely calculated in the observer's inertial frame, and which is consistent
with the well-understood rotational effects of aberration and retardation. We
explore the observational consequences of the model, including (1) the
appearance of the reconstructed beam pattern via the cartographic transform and
(2) the morphology of drift bands and how they might evolve as a function of
frequency. The model, which is implemented in the software package PSRGEOM, is
applicable to a wide range of viewing geometries, and we illustrate its
implications using PSRs B0809+74 and B2034+19 as examples. Some specific
predictions are made with respect to the difference between subpulse evolution
and microstructure evolution, which provides a way to further test our model.
| arxiv topic:astro-ph.HE |
arxiv_dataset-105821812.00626 | Exotic decay channels are not the cause of the neutron lifetime anomaly
nucl-ex hep-ex
Since long neutron lifetimes measured with a beam of cold neutrons are
significantly different from lifetimes measured with ultracold neutrons bottled
in a trap. It is often speculated that this "neutron anomaly" is due to an
exotic dark neutron decay channel of unknown origin. We show that this
explanation of the neutron anomaly can be excluded with a high level of
confidence when use is made of new data on neutron decay parameters.
Furthermore, data from neutron decay now compare well with Ft data derived from
nuclear \b{eta} decays.
| arxiv topic:nucl-ex hep-ex |
arxiv_dataset-105831812.00726 | Averaging Principle and Shape Theorem for a Growth Model with Memory
math.PR
We present a general approach to study a class of random growth models in
$n$-dimensional Euclidean space. These models are designed to capture basic
growth features which are expected to manifest at the mesoscopic level for
several classical self-interacting processes originally defined at the
microscopic scale. It includes once-reinforced random walk with strong
reinforcement, origin-excited random walk, and few others, for which the set of
visited vertices is expected to form a "limiting shape". We prove an averaging
principle that leads to such shape theorem. The limiting shape can be computed
in terms of the invariant measure of an associated Markov chain.
| arxiv topic:math.PR |
arxiv_dataset-105841812.00826 | Flat approximations of hypersurfaces along curves
math.DG
Given a smooth curve $\gamma$ in some $m$-dimensional surface $M$ in
$\mathbb{R}^{m+1}$, we study existence and uniqueness of a flat surface $H$
having the same field of normal vectors as $M$ along $\gamma$, which we call a
flat approximation of $M$ along $\gamma$. In particular, the well-known
characterisation of flat surfaces as torses (ruled surfaces with tangent plane
stable along the rulings) allows us to give an explicit parametric construction
of such approximation.
| arxiv topic:math.DG |
arxiv_dataset-105851812.00926 | Complex Structures for Klein-Gordon Theory on Globally Hyperbolic
Spacetimes
math-ph gr-qc hep-th math.MP
We develop a rigorous method to parametrize complex structures for
Klein-Gordon theory in globally hyperbolic spacetimes that satisfy a
completeness condition. The complex structures are conserved under
time-evolution and implement unitary quantizations. They can be interpreted as
corresponding to global choices of vacuum. The main ingredient in our
construction is a system of operator differential equations. We provide a
number of theorems ensuring that all ingredients and steps in the construction
are well-defined. We apply the method to exhibit natural quantizations for
certain classes of globally hyperbolic spacetimes. In particular, we consider
static, expanding and Friedmann-Robertson-Walker spacetimes. Moreover, for a
huge class of spacetimes we prove that the differential equation for the
complex structure is given by the Gelfand-Dikki equation.
| arxiv topic:math-ph gr-qc hep-th math.MP |
arxiv_dataset-105861812.01026 | Mass Deformations of the ABJM Theory: The Holographic Free Energy
hep-th
We find a class of new supersymmetric Euclidean solutions in four-dimensional
maximal gauged supergravity. The holographic dual description of these
backgrounds is given by a mass-deformation of the ABJM theory with general
values for the R-charges. We calculate the $S^3$ free energy for the
supergravity backgrounds and find agreement with the supersymmetric
localization calculation of the free energy in the large $N$ limit.
| arxiv topic:hep-th |
arxiv_dataset-105871812.01126 | Wideband Full-Duplex Wireless via Frequency-Domain Equalization: Design
and Experimentation
eess.SP cs.NI
Full-duplex (FD) wireless can significantly enhance spectrum efficiency but
requires tremendous amount of self-interference (SI) cancellation. Recent
advances in the RFIC community enabled wideband RF SI cancellation (SIC) in
integrated circuits (ICs) via frequency-domain equalization (FDE), where RF
filters channelize the SI signal path. Unlike other FD implementations, that
mostly rely on delay lines, FDE-based cancellers can be realized in
small-form-factor devices. However, the fundamental limits and higher layer
challenges associated with these cancellers were not explored yet. Therefore,
and in order to support the integration with a software-defined radio (SDR) and
to facilitate experimentation in a testbed with several nodes, we design and
implement an FDE-based RF canceller on a printed circuit board (PCB). We derive
and experimentally validate the PCB canceller model and present a canceller
configuration scheme based on an optimization problem. We then extensively
evaluate the performance of the FDE-based FD radio in the SDR testbed.
Experiments show that it achieves 95dB overall SIC (52dB from RF SIC) across
20MHz bandwidth, and an average link-level FD gain of 1.87x. We also conduct
experiments in: (i) uplink-downlink networks with inter-user interference, and
(ii) heterogeneous networks with half-duplex and FD users. The experimental FD
gains in the two types of networks confirm previous analytical results. They
depend on the users' SNR values and the number of FD users, and are 1.14x-1.25x
and 1.25x-1.73x, respectively. Finally, we numerically evaluate and compare the
RFIC and PCB implementations and study various design tradeoffs.
| arxiv topic:eess.SP cs.NI |
arxiv_dataset-105881812.01226 | Learning Vine Copula Models For Synthetic Data Generation
cs.LG stat.ML
A vine copula model is a flexible high-dimensional dependence model which
uses only bivariate building blocks. However, the number of possible
configurations of a vine copula grows exponentially as the number of variables
increases, making model selection a major challenge in development. In this
work, we formulate a vine structure learning problem with both vector and
reinforcement learning representation. We use neural network to find the
embeddings for the best possible vine model and generate a structure.
Throughout experiments on synthetic and real-world datasets, we show that our
proposed approach fits the data better in terms of log-likelihood. Moreover, we
demonstrate that the model is able to generate high-quality samples in a
variety of applications, making it a good candidate for synthetic data
generation.
| arxiv topic:cs.LG stat.ML |
arxiv_dataset-105891812.01326 | Values of Harmonic Weak Maass forms on Hecke orbits
math.NT
Let $q:=e^{2 \pi iz}$, where $z \in \mathbb{H}$. For an even integer $k$, let
$f(z):=q^h\prod_{m=1}^{\infty}(1-q^m)^{c(m)}$ be a meromorphic modular form of
weight $k$ on $\Gamma_0(N)$. For a positive integer $m$, let $T_m$ be the $m$th
Hecke operator and $D$ be a divisor of a modular curve with level $N$. Both
subjects, the exponents $c(m)$ of a modular form and the distribution of the
points in the support of $T_m. D$, have been widely investigated.
When the level $N$ is one, Bruinier, Kohnen, and Ono obtained, in terms of
the values of $j$-invariant function, identities between the exponents $c(m)$
of a modular form and the points in the support of $T_m.D$. In this paper, we
extend this result to general $\Gamma_0(N)$ in terms of values of harmonic weak
Maass forms of weight $0$. By the distribution of Hecke points, this applies to
obtain an asymptotic behaviour of convolutions of sums of divisors of an
integer and sums of exponents of a modular form.
| arxiv topic:math.NT |
arxiv_dataset-105901812.01426 | Combinatorial persistency criteria for multicut and max-cut
math.OC
In combinatorial optimization, partial variable assignments are called
persistent if they agree with some optimal solution. We propose persistency
criteria for the multicut and max-cut problem as well as fast combinatorial
routines to verify them. The criteria that we derive are based on mappings that
improve feasible multicuts, respectively cuts. Our elementary criteria can be
checked enumeratively. The more advanced ones rely on fast algorithms for upper
and lower bounds for the respective cut problems and max-flow techniques for
auxiliary min-cut problems. Our methods can be used as a preprocessing
technique for reducing problem sizes or for computing partial optimality
guarantees for solutions output by heuristic solvers. We show the efficacy of
our methods on instances of both problems from computer vision, biomedical
image analysis and statistical physics.
| arxiv topic:math.OC |
arxiv_dataset-105911812.01526 | On the uniqueness of infinity-categorical enhancements of triangulated
categories
math.AG math.AT
We study the problem of when triangulated categories admit unique
infinity-categorical enhancements. Our results use Lurie's theory of prestable
infinity-categories to give conceptual proofs of, and in many cases strengthen,
previous work on the subject by Lunts--Orlov and Canonaco--Stellari. We also
give a wide range of examples involving quasi-coherent sheaves, categories of
almost modules, and local cohomology to illustrate the theory of prestable
infinity-categories. Finally, we propose a theory of stable $n$-categories
which would interpolate between triangulated categories and stable
infinity-categories.
| arxiv topic:math.AG math.AT |
arxiv_dataset-105921812.01626 | Structure of a protobinary system: an asymmetric circumbinary disk and
spiral arms
astro-ph.SR
We investigate the gas structures around young binary stars by using
three-dimensional numerical simulations. Each model exhibits circumstellar
disks, spiral arms, and a circumbinary disk with an inner gap or cavity. The
circumbinary disk has an asymmetric pattern rotating at an angular velocity of
approximately one-fourth of the binary orbit of the moderate-temperature
models. Because of this asymmetry, the circumbinary disk has a density bump and
a vortex, both of which continue to exist until the end of our calculation. The
density bump and vortex are attributed to enhanced angular momentum, which is
promoted by the gravitational torque of the stars. In a hot model ($c \ge
2.0$), the asymmetry rotates considerably more slowly than in the
moderate-temperature models. The cold models ($c \le 0.02$) exhibit eccentric
circumbinary disks, the precession of which is approximated by a secular motion
of the ballistic particles. The asymmetry in the circumbinary disk does not
depend on the mass ratio, but it becomes less clear as the specific angular
momentum of the infalling envelope increases. The relative accretion rate onto
the stars is sensitive to the angular momentum of the infalling envelope. For
envelopes with constant angular momentum, the secondary tends to have a higher
accretion rate than the primary, except in very low angular momentum cases. For
envelopes with a constant angular velocity, the primary has a higher accretion
rate than the secondary because gas with low specific angular momentum falls
along the polar directions.
| arxiv topic:astro-ph.SR |
arxiv_dataset-105931812.01726 | NY Vir Eclipse timing observations: Two planet solution
astro-ph.EP
We report 18 new primary minima timing observations of the short-period
eclipsing binary system NY Virginis. We combined these minima with previously
published primary minima to update circumbinary exoplanet models in this system
based on O-C timing variations. We performed a non-linear least-squares
minimization search using a quadratic ephemeris and either one or two
exoplanets. The only model with an acceptable fit includes a period derivative
$\dot{P} = 2.83\times10^{-12}$ and two planets in eccentric orbits $e =
0.15,0.15$ with minimum masses 2.7 and 5.5 Jovian masses. Analysis of the orbit
stability shows that this solution is stable for at least $10^8$ yr, but a
small increase in eccentricity ($e\geq0.20$) for either planet renders the
orbits unstable in less than $10^6$ years. A number of model parameters are
significantly degenerate, so additional observations are required to determine
planetary parameters with high statistical confidence.
| arxiv topic:astro-ph.EP |
arxiv_dataset-105941812.01826 | Spectral gaps for the O-U/Stochastic heat processes on path space over a
Riemannian manifold with boundary
math.PR
Fang-Wu\cite{FW17} presented a explicit spectral gap for the O-U process on
path space over a Riemannian manifold without boundary under the bounded Ricci
curvature conditions. In this paper, we will extend these results to the case
of the Riemannian manifold with boundary. Moreover, we also derive the similar
results for the stochastic heat process.
| arxiv topic:math.PR |
arxiv_dataset-105951812.01926 | Entrance laws at the origin of self-similar Markov processes in high
dimensions
math.PR
In this paper we consider the problem of finding entrance laws at the origin
for self-similar Markov processes in $\mathbb{R}^d$, killed upon hitting the
origin. Under mild assumptions, we show the existence of an entrance law and
the convergence to this law when the process is started close to the origin. We
obtain an explicit description of the process started from the origin as the
time reversal of the original self-similar Markov process conditioned to hit
the origin.
| arxiv topic:math.PR |
arxiv_dataset-105961812.02026 | The structure monoid and algebra of a non-degenerate set-theoretic
solution of the Yang-Baxter equation
math.RA
For a finite involutive non-degenerate solution $(X,r)$ of the Yang--Baxter
equation it is known that the structure monoid $M(X,r)$ is a monoid of I-type,
and the structure algebra $K[M(X,r)]$ over a field $K$ share many properties
with commutative polynomial algebras, in particular, it is a Noetherian
PI-domain that has finite Gelfand--Kirillov dimension. In this paper we deal
with arbitrary finite (left) non-degenerate solutions. Although the structure
of both the monoid $M(X,r)$ and the algebra $K[M(X,r)]$ is much more
complicated than in the involutive case, we provide some deep insights.
In this general context, using a realization of Lebed and Vendramin of
$M(X,r)$ as a regular submonoid in the semidirect product
$A(X,r)\rtimes\mathrm{Sym}(X)$, where $A(X,r)$ is the structure monoid of the
rack solution associated to $(X,r)$, we prove that $K[M(X,r)]$ is a module
finite normal extension of a commutative affine subalgebra. In particular,
$K[M(X,r)]$ is a Noetherian PI-algebra of finite Gelfand--Kirillov dimension
bounded by $|X|$. We also characterize, in ring-theoretical terms of
$K[M(X,r)]$, when $(X,r)$ is an involutive solution. This characterization
provides, in particular, a positive answer to the Gateva-Ivanova conjecture
concerning cancellativity of $M(X,r)$.
These results allow us to control the prime spectrum of the algebra
$K[M(X,r)]$ and to describe the Jacobson radical and prime radical of
$K[M(X,r)]$. Finally, we give a matrix-type representation of the algebra
$K[M(X,r)]/P$ for each prime ideal $P$ of $K[M(X,r)]$. As a consequence, we
show that if $K[M(X,r)]$ is semiprime then there exist finitely many finitely
generated abelian-by-finite groups, $G_1,\dotsc,G_m$, each being the group of
quotients of a cancellative subsemigroup of $M(X,r)$ such that the algebra
$K[M(X,r)]$ embeds into $\mathrm{M}_{v_1}(K[G_1])\times\dotsb\times
\mathrm{M}_{v_m}(K[G_m])$.
| arxiv topic:math.RA |
arxiv_dataset-105971812.02126 | Dynamical signatures of topological order in the driven-dissipative
Kitaev chain
cond-mat.str-el cond-mat.mes-hall
We investigate the effects of dissipation and driving on topological order in
superconducting nanowires. Rather than studying the non-equilibrium steady
state, we propose a method to classify and detect dynamical signatures of
topological order in open quantum systems. Bulk winding numbers for the
Lindblad generator $\hat{\mathcal{L}}$ of the dissipative Kitaev chain are
found to be linked to the presence of Majorana edge master modes -- localized
eigenmodes of $\hat{\mathcal{L}}$. Despite decaying in time, these modes
provide dynamical fingerprints of the topological phases of the closed system,
which are now separated by intermediate regions where winding numbers are
ill-defined and the bulk-boundary correspondence breaks down. Combining these
techniques with the Floquet formalism reveals higher winding numbers and
different types of edge modes under periodic driving. Finally, we link the
presence of edge modes to a steady state current.
| arxiv topic:cond-mat.str-el cond-mat.mes-hall |
arxiv_dataset-105981812.02226 | Light-state Dominance from the Conformal Bootstrap
hep-th cond-mat.stat-mech cond-mat.str-el
We derive forms of light-state dominance for correlators in CFT$_d$, making
precise the sense in which correlators can be approximated by the contribution
of light operator exchanges. Our main result is that the four-point function of
operators with dimension $\Delta$ is approximated, with bounded error, by the
contribution of operators with scaling dimension below $\Delta_c > 2\Delta$ in
the appropriate OPE channel. Adapting an existing modular invariance argument,
we use crossing symmetry to show that the heavy-state contribution is
suppressed by a relative factor of $e^{2\Delta-\Delta_c}$. We extend this
result to the first sheet and derivatives of the correlator. Further exploiting
technical similarities between crossing and modular invariance, we prove
analogous results for the $2d$ partition function along the way.
We then turn to effective field theory in gapped theories and AdS/CFT, and
make some general comments about the effect of integrating out heavy particles
in the bulk. Combining our bounds with the Lorentzian OPE inversion formula we
show that, under certain conditions, light-state dominance implies that
integrating out heavy exchanges leads to higher-derivative couplings suppressed
at large $\Delta_{gap}$.
| arxiv topic:hep-th cond-mat.stat-mech cond-mat.str-el |
arxiv_dataset-105991812.02326 | Solar Neutrino Measurements
nucl-ex astro-ph.SR hep-ex
We present the most recent results from the two currently running solar
neutrino experiments, Borexino at the Gran Sasso laboratory in Italy and SuperK
at Kamioka mine in Japan. SuperK has released the most precise yet measurement
of the 8B solar neutrino interaction rate, with a precision better than 2\%,
consistent with a constant solar neutrino emission over more than a decade.
Borexino has released refined measurements of all neutrinos produced in the pp
fusion chain. For the first time, one single detector has measured the entire
range of solar neutrinos at once. These new data weakly favor a
high-metallicity Sun. Prospects for measuring CNO solar neutrinos with Borexino
are discussed, and a brief outlook on the field provided.
| arxiv topic:nucl-ex astro-ph.SR hep-ex |
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