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1602.08663 | In this paper, we consider a finite difference grid-based semi-Lagrangian
approach in solving the Vlasov-Poisson (VP) system. Many of existing methods
are based on dimensional splitting, which decouples the problem into solving
linear advection problems, see {\em Cheng and Knorr, Journal of Computational
Physics, 22(1976)}. However, such splitting is subject to the splitting error.
If we consider multi-dimensional problems without splitting, difficulty arises
in tracing characteristics with high order accuracy. Specifically, the
evolution of characteristics is subject to the electric field which is
determined globally from the distribution of particle densities via the
Poisson's equation. In this paper, we propose a novel strategy of tracing
characteristics high order in time via a two-stage multi-derivative
prediction-correction approach and by using moment equations of the VP system.
With the foot of characteristics being accurately located, we proposed to use
weighted essentially non-oscillatory (WENO) interpolation to recover function
values between grid points, therefore to update solutions at the next time
level. The proposed algorithm does not have time step restriction as Eulerian
approach and enjoys high order spatial and temporal accuracy. However, such
finite difference algorithm does not enjoy mass conservation; we discuss one
possible way of resolving such issue and its potential challenge in numerical
stability. The performance of the proposed schemes are numerically demonstrated
via classical test problems such as Landau damping and two stream
instabilities.
| [
"math.NA"
] | math.NA | Numerical Analysis | 5,002Numerical Analysis
|
|
2310.06574 | We propose an approach for early crop classification through identifying
important timesteps with eXplainable AI (XAI) methods. Our approach consists of
training a baseline crop classification model to carry out layer-wise relevance
propagation (LRP) so that the salient time step can be identified. We chose a
selected number of such important time indices to create the bounding region of
the shortest possible classification timeframe. We identified the period 21st
April 2019 to 9th August 2019 as having the best trade-off in terms of accuracy
and earliness. This timeframe only suffers a 0.75% loss in accuracy as compared
to using the full timeseries. We observed that the LRP-derived important
timesteps also highlight small details in input values that differentiates
between different classes and
| [
"cs.LG",
"stat.AP",
"stat.ML"
] | cs.LG | stat.AP | Machine Learning;Applications;Machine Learning | 3,888Machine Learning;Applications;Machine Learning
|
2304.01436 | We propose a method to learn a high-quality implicit 3D head avatar from a
monocular RGB video captured in the wild. The learnt avatar is driven by a
parametric face model to achieve user-controlled facial expressions and head
poses. Our hybrid pipeline combines the geometry prior and dynamic tracking of
a 3DMM with a neural radiance field to achieve fine-grained control and
photorealism. To reduce over-smoothing and improve out-of-model expressions
synthesis, we propose to predict local features anchored on the 3DMM geometry.
These learnt features are driven by 3DMM deformation and interpolated in 3D
space to yield the volumetric radiance at a designated query point. We further
show that using a Convolutional Neural Network in the UV space is critical in
incorporating spatial context and producing representative local features.
Extensive experiments show that we are able to reconstruct high-quality
avatars, with more accurate expression-dependent details, good generalization
to out-of-training expressions, and quantitatively superior renderings compared
to other state-of-the-art approaches.
| [
"cs.CV",
"cs.GR"
] | cs.CV | cs.GR | Computer Vision and Pattern Recognition;Graphics | 1,568Computer Vision and Pattern Recognition;Graphics
|
2107.13879 | In recent years, numerous studies have been published dealing with the effect
of individual characteristics of pedestrians on the fundamental diagram. These
studies compared cumulative data on individuals in a group homogeneous in terms
of one human factor such as age but heterogeneous in terms of other factors for
instance gender. In order to examine the effect of all determined as well as
undetermined human factors, individual fundamental diagrams are introduced and
analyzed using multiple linear regression. A single-file school experiment with
students of different age, gender, and height is therefore considered. Single
individuals appearing in different runs are analyzed to study the effect of
human factors such as height, age and gender and all other unknown individual
effects such as motivation or attention to the individual speed. The analysis
shows that for students age and height are strongly correlated and,
consequently, age can be ignored. Furthermore, the study shows that gender has
a weak effect and other nonmeasurable individual characteristics have a
stronger effect than height. In a further step, a mixed model is used as well
as the multiple linear model. Here, it is shown that the mixed model that
considers all other unknown individual effects of each person as a random
factor is preferable to the model where the individual speed only depends on
the variables of headway, height, and all other unknown individual effects as
fixed factors.
| [
"physics.soc-ph"
] | physics.soc-ph | Physics and Society | 5,463Physics and Society
|
|
1610.02742 | Providing users of HPC systems with a wide variety of up to date software
packages is a challenging task. Large software stacks built from source are
difficult to manage, requiring powerful package management tools. The Portage
package manager from Gentoo is a highly flexible tool that offers a mature
solution to this otherwise daunting task. The Gentoo Prefix project develops
and maintains a way of installing Gentoo systems in non-standard locations,
bringing the virtues of Gentoo to other operating systems. Here we demonstrate
how a Gentoo Prefix installation can be used to cross compile software packages
for the Intel Xeon Phi known as Knights Corner, as well as to manage large
software stacks in HPC environments.
| [
"cs.DC"
] | cs.DC | Distributed, Parallel, and Cluster Computing | 2,194Distributed, Parallel, and Cluster Computing
|
|
1202.5055 | This paper is dedicated to study weighted $L^p$ inequalities for
pseudo-differential operators with amplitudes and their commutators by using
the new class of weights $A_p^\vc$ and the new BMO function space BMO$_\vc$
which are larger than the Muckenhoupt class of weights $A_p$ and classical BMO
space BMO, respectively. The obtained results therefore improve substantially
some well-known results.
| [
"math.CA"
] | math.CA | Classical Analysis and ODEs | 934Classical Analysis and ODEs
|
|
0707.1868 | We present experimental magnetotunneling results and atomistic
pseudopotential calculations of quasiparticle electron and hole wave functions
of self-assembled InAs/GaAs quantum dots. The combination of a predictive
theory along with the experimental results allows us to gain direct insight
into the quantum states. We monitor the effects of (i) correlations, (ii)
atomistic symmetry and (iii) piezoelectricity on the confined carriers and (iv)
observe a peculiar charging sequence of holes that violates the Aufbau
principle.
| [
"cond-mat.mtrl-sci"
] | cond-mat.mtrl-sci | Materials Science | 4,287Materials Science
|
|
2305.02185 | We consider a panel data analysis to examine the heterogeneity in treatment
effects with respect to a pre-treatment covariate of interest in the staggered
difference-in-differences setting of Callaway and Sant'Anna (2021). Under
standard identification conditions, a doubly robust estimand conditional on the
covariate identifies the group-time conditional average treatment effect given
the covariate. Focusing on the case of a continuous covariate, we propose a
three-step estimation procedure based on nonparametric local polynomial
regressions and parametric estimation methods. Using uniformly valid
distributional approximation results for empirical processes and multiplier
bootstrapping, we develop doubly robust inference methods to construct uniform
confidence bands for the group-time conditional average treatment effect
function. The accompanying R package didhetero allows for easy implementation
of the proposed methods.
| [
"econ.EM",
"stat.ME"
] | econ.EM | stat.ME | Econometrics;Methodology | 2,406Econometrics;Methodology
|
astro-ph/0702732 | Filled arrays of bolometers are currently being employed for use in astronomy
from the far-infrared through millimeter parts of the electromagnetic spectrum.
Because of the large range of wavelengths for which such detectors are
applicable, the number of modes supported by a pixel will vary according to the
specific application of a given available technology. We study the dependence
of image fidelity and induced polarization on the size of the pixel by
employing a formalism in which diffraction due to the pixel boundary is treated
by propagating the second-order statistical correlations of the radiation field
through a model optical system. We construct polarized beam pattern images of
square pixels for various ratios of p/\lambda where p is the pixel size and
\lambda is the wavelength of the radiation under consideration. For the limit
in which few modes are supported by the pixel (p/\lambda<1), we find that the
diffraction due to the pixel edges is non-negligible and hence must be
considered along with the telescope diffraction pattern in modeling the
ultimate spatial resolution of an imaging system. For the case in which the
pixel is over-moded (p/\lambda>1), the geometric limit is approached as
expected. This technique gives a quantitative approach to optimize the imaging
properties of arrays of planar detectors in the few-mode limit.
| [
"astro-ph"
] | astro-ph | Astrophysics | 463Astrophysics
|
|
1810.00198 | In the last few years, there has been a resurgence of interest in obtaining
observational bounds on the graviton mass, following the detection of
gravitational waves, because of the versatility of massive graviton theories in
resolving multiple problems in cosmology and fundamental physics. In this work,
we apply the method proposed in Rana et al.(arXiv:1801.03309), which consists
of looking for Yukawa-like fall off in the gravitational potential, to stacked
galaxy cluster catalogs from three disparate surveys. These include catalogs
from 2500 sq. degree SPT-SZ survey, the Planck all-sky SZ catalog, and a
redMaPPer selected catalog from 10,000 sq. degree of SDSS-DR8 data. The 90\%
c.l. limits which we obtained on the graviton mass using SPT, Planck and SDSS
are: $m_g < 4.73 \times 10^{-30}$ eV, $3.0 \times 10^{-30}$ eV, and $1.27
\times 10^{-30}$ eV respectively; or in terms of Compton wavelength are
$\lambda_g >2.62 \times 10^{20}$ km, $4.12 \times 10^{20}$ km, $9.76 \times
10^{20}$ km. These limits are about five times more stringent than the previous
best bound from galaxy clusters.
| [
"astro-ph.CO",
"gr-qc"
] | astro-ph.CO | gr-qc | Cosmology and Nongalactic Astrophysics;General Relativity and Quantum Cosmology | 1,745Cosmology and Nongalactic Astrophysics;General Relativity and Quantum Cosmology
|
0901.0121 | For a graph $G$ let $L(G)$ and $l(G)$ denote the size of the largest and
smallest maximum matching of a graph obtained from $G$ by removing a maximum
matching of $G$. We show that $L(G)\leq 2l(G),$ and $L(G)\leq (3/2)l(G)$
provided that $G$ contains a perfect matching. We also characterize the class
of graphs for which $L(G)=2l(G)$. Our characterization implies the existence of
a polynomial algorithm for testing the property $L(G)=2l(G)$. Finally we show
that it is $NP$-complete to test whether a graph $G$ containing a perfect
matching satisfies $L(G)=(3/2)l(G)$.
| [
"cs.DM",
"math.CO"
] | cs.DM | math.CO | Discrete Mathematics;Combinatorics | 2,104Discrete Mathematics;Combinatorics
|
1709.03220 | With the rapid proliferation and adoption of social media among healthcare
professionals and organizations, social media-based HIV/AIDS intervention
programs have become increasingly popular. However, the question of the
effectiveness of the HIV/AIDS messages disseminated via social media has
received scant attention in the literature. The current study applies content
analysis to examine the relationship between Facebook messaging strategies
employed by 110 HIV/AIDS nonprofit organizations and audience reactions in the
form of liking, commenting, and sharing behavior. The results reveal that
HIV/AIDS nonprofit organizations often use informational messages as one-way
communication with their audience instead of dialogic interactions. Some
specific types of messages, such as medication-focused messages, engender
better audience engagement, in contrast, event-related messages and
call-to-action messages appear to translate into lower corresponding audience
reactions. The findings provide guidance to HIV/AIDS organizations in
developing effective social media communication strategies.
| [
"cs.CY"
] | cs.CY | Computers and Society | 1,646Computers and Society
|
|
physics/0008116 | We describe use of the Advanced Photon Source (APS) rf thermionic gun, alpha
magnet beamline, and linac to produce a stable high-brightness beam in excess
of 100 amperes peak current with normalized emittance of 10 pi mm-mrad. To
obtain peak currents greater than 100 amperes, the rf gun system must be tuned
to produce a FWHM bunch length on the order of 350 fs. Bunch lengths this short
are measured using coherent transition radiation (CTR) produced when the rf gun
beam, accelerated to 40 MeV, strikes a metal foil. The CTR is detected using a
Golay detector attached to one arm of a Michelson interferometer. The alpha
magnet current and gun rf phase are adjusted so as to maximize the CTR signal
at the Golay detector, which corresponds to the minimum bunch length. The
interferometer is used to measure the autocorrelation of the CTR radiation. The
minimum phase approximation is used to derive the bunch profile from the
autocorrelation. The high-brightness beam is accelerated to 217 MeV and used to
produce SASE in five APS undulators installed in the Low- Energy Undulator Test
Line (LEUTL) experiment hall. Initial optical measurements showed a gain length
of 1.3 m at 530 nm. * Work supported by U. S. Department of Energy, Office of
Basic Energy Sciences, under Contract No. W-31-109-ENG-38.
| [
"physics.acc-ph"
] | physics.acc-ph | Accelerator Physics | 0Accelerator Physics
|
|
1306.4394 | We compare the electronic characteristics of nanowire field-effect
transistors made using single pure wurtzite and pure zincblende InAs nanowires
with nominally identical diameter. We compare the transfer characteristics and
field-effect mobility versus temperature for these devices to better understand
how differences in InAs phase govern the electronic properties of nanowire
transistors.
| [
"cond-mat.mes-hall"
] | cond-mat.mes-hall | Mesoscale and Nanoscale Physics | 4,450Mesoscale and Nanoscale Physics
|
|
1908.02710 | This article describes a probabilistic formulation of a Weighted Power
minimization Distortionless response convolutional beamformer (WPD). The WPD
unifies a weighted prediction error based dereverberation method (WPE) and a
minimum power distortionless response beamformer (MPDR) into a single
convolutional beamformer, and achieves simultaneous dereverberation and
denoising in an optimal way. However, the optimization criterion is obtained
simply by combining existing criteria without any clear theoretical
justification. This article presents a generative model and a probabilistic
formulation of a WPD, and derives an optimization algorithm based on a maximum
likelihood estimation. We also describe a method for estimating the steering
vector of the desired signal by utilizing WPE within the WPD framework to
provide an effective and efficient beamformer for denoising and
dereverberation.
| [
"eess.AS",
"cs.SD"
] | eess.AS | cs.SD | Audio and Speech Processing;Sound | 667Audio and Speech Processing;Sound
|
1303.0330 | Many biological fluids have polymeric microstructures and display
non-Newtonian rheology. We take advantage of such nonlinear fluid behavior and
combine it with geometrical symmetry-breaking to design a novel small-scale
propeller able to move only in complex fluids. Its propulsion characteristics
are explored numerically in an Oldroyd-B fluid for finite Deborah numbers while
the small Deborah number limit is investigated analytically using a
second-order fluid model. We then derive expressions relating the propulsion
speed to the rheological properties of the complex fluid, allowing thus to
infer the normal stress coefficients in the fluid from the locomotion of the
propeller. Our simple mechanism can therefore be used either as a non-Newtonian
micro-propeller or as a micro-rheometer.
| [
"physics.flu-dyn"
] | physics.flu-dyn | Fluid Dynamics | 2,452Fluid Dynamics
|
|
1904.02914 | The quadratic cycle cover problem is the problem of finding a set of
node-disjoint cycles visiting all the nodes such that the total sum of
interaction costs between consecutive arcs is minimized. In this paper we study
the linearization problem for the quadratic cycle cover problem and related
lower bounds.
In particular, we derive various sufficient conditions for the quadratic cost
matrix to be linearizable, and use these conditions to compute bounds. We also
show how to use a sufficient condition for linearizability within an iterative
bounding procedure. In each step, our algorithm computes the best equivalent
representation of the quadratic cost matrix and its optimal linearizable matrix
with respect to the given sufficient condition for linearizability. Further, we
show that the classical Gilmore-Lawler type bound belongs to the family of
linearization based bounds, and therefore apply the above mentioned iterative
reformulation technique. We also prove that the linearization vectors resulting
from this iterative approach satisfy the constant value property.
The best among here introduced bounds outperform existing lower bounds when
taking both quality and efficiency into account.
| [
"math.OC"
] | math.OC | Optimization and Control | 5,234Optimization and Control
|
|
astro-ph/0612329 | The flux from distant type Ia supernovae (SN) is likely to be amplified or
de-amplified by gravitational lensing due to matter distributions along the
line-of-sight. A gravitationally lensed SN would appear brighter or fainter
than the average SN at a particular redshift. We estimate the magnification of
26 SNe in the GOODS fields and search for a correlation with the residual
magnitudes of the SNe. The residual magnitude, i.e. the difference between
observed and average magnitude predicted by the "concordance model" of the
Universe, indicates the deviation in flux from the average SN. The linear
correlation coefficient for this sample is r=0.29. For a similar, but
uncorrelated sample, the probability of obtaining a correlation coefficient
equal to or higher than this value is ~10%, i.e. a tentative detection of
lensing at ~90% confidence level. Although the evidence for a correlation is
weak, our result is in accordance with what could be expected given the small
size of the sample.
| [
"astro-ph"
] | astro-ph | Astrophysics | 463Astrophysics
|
|
2201.13294 | We investigate the early time development of the anisotropic transverse flow
and spatial eccentricities of a fireball with various particle-based transport
approaches using a fixed initial condition. In numerical simulations ranging
from the quasi-collisionless case to the hydrodynamic regime, we find that the
onset of $v_n$ and of related measures of anisotropic flow can be described
with a simple power-law ansatz, with an exponent that depends on the amount of
rescatterings in the system. In the few-rescatterings regime we perform
semi-analytical calculations, based on a systematic expansion in powers of time
and the cross section, which can reproduce the numerical findings.
| [
"nucl-th",
"hep-ph",
"physics.flu-dyn"
] | nucl-th | hep-ph | Nuclear Theory;High Energy Physics - Phenomenology;Fluid Dynamics | 4,916Nuclear Theory;High Energy Physics - Phenomenology;Fluid Dynamics
|
0908.3058 | Spin-1/2 Ising-Heisenberg model with XYZ Heisenberg pair interaction and two
different Ising quartic interactions is exactly solved with the help of the
generalized star-square transformation, which establishes a precise mapping
equivalence with the corresponding eight-vertex model on a square lattice
generally satisfying Baxter's zero-field (symmetric) condition. The
investigated model exhibits a remarkable weak-universal critical behavior with
two marked wings of critical lines along which critical exponents vary
continuously with the interaction parameters. Both wings of critical lines
merge together at a very special quantum critical point of the infinite order,
which can be characterized through diverging critical exponents. The
possibility of observing reentrant phase transitions in a close vicinity of the
quantum critical point is related to a relative strength of the exchange
anisotropy in the XYZ Heisenberg pair interaction.
| [
"cond-mat.stat-mech"
] | cond-mat.stat-mech | Statistical Mechanics | 6,821Statistical Mechanics
|
|
1908.01594 | The purpose of this work is to develop a deep learning-based method for knee
menisci segmentation in 3D ultrashort echo time (UTE) cones magnetic resonance
(MR) imaging, and to automatically determine MR relaxation times, namely the
T1, T1$\rho$, and T2* parameters, which can be used to assess knee
osteoarthritis (OA). Whole knee joint imaging was performed using 3D UTE cones
sequences to collect data from 61 human subjects. Regions of interest (ROIs)
were outlined by two experienced radiologists based on subtracted
T1$\rho$-weighted MR images. Transfer learning was applied to develop 2D
attention U-Net convolutional neural networks for the menisci segmentation
based on each radiologist's ROIs separately. Dice scores were calculated to
assess segmentation performance. Next, the T1, T1$\rho$, T2* relaxations, and
ROI areas were determined for the manual and automatic segmentations, then
compared.The models developed using ROIs provided by two radiologists achieved
high Dice scores of 0.860 and 0.833, while the radiologists' manual
segmentations achieved a Dice score of 0.820. Linear correlation coefficients
for the T1, T1$\rho$, and T2* relaxations calculated using the automatic and
manual segmentations ranged between 0.90 and 0.97, and there were no associated
differences between the estimated average meniscal relaxation parameters. The
deep learning models achieved segmentation performance equivalent to the
inter-observer variability of two radiologists. The proposed deep
learning-based approach can be used to efficiently generate automatic
segmentations and determine meniscal relaxations times. The method has the
potential to help radiologists with the assessment of meniscal diseases, such
as OA.
| [
"eess.IV",
"cs.CV",
"physics.med-ph"
] | eess.IV | cs.CV | Image and Video Processing;Computer Vision and Pattern Recognition;Medical Physics | 3,545Image and Video Processing;Computer Vision and Pattern Recognition;Medical Physics
|
2302.10155 | This work is focused on the exploration of the thermodynamics foundations of
the matter creation scenario when a generalized form of the second law of
thermodynamics for this scheme is implemented. In this scenario we consider an
expanding cosmology in which the created matter is trapped by the apparent
horizon. The scheme leads to phantom evolution but at first glance it lacks of
physical consistency. However, the inclusion of chemical potential into the
description solves the thermodynamics issues of the model and determines the
behavior of the cosmic fluid, in other words, the cosmic fluid now can behave
as phantom dark energy or as quintessence one.
| [
"gr-qc"
] | gr-qc | General Relativity and Quantum Cosmology | 2,674General Relativity and Quantum Cosmology
|
|
1508.02355 | For $p,q\geq2$, the Hardy and Littlewood inequalities for real bilinear
forms, in its unified formulation, assert that there is a constant
$C_{p,q}\geq1$ such that \begin{equation}
\left(\sum\limits_{j=1}^{\infty}\left(\sum\limits_{k=1}^{\infty}\left\vert
A(e_{j},e_{k})\right\vert ^{2}\right) ^{\frac{\lambda}{2}}\right) ^{\frac
{1}{\lambda}}\leq C_{p,q}\left\Vert A\right\Vert, \end{equation} with sharp
exponent $\lambda=\frac{pq}{pq-p-q},$ for all continuous bilinear forms
$A:\ell_{p}\times\ell_{q}\rightarrow\mathbb{R}$ (as usual, $c_{0}$ replaces
$\ell_{p}$ or $\ell_{q}$ when $p=\infty$ or $q=\infty$)$.$ In this note, among
other results, we show that the sharp constants $C_{p,\infty}$ are precisely \[
C_{p,\infty}=2^{\frac{1}{2}-\frac{1}{p}}% \] whenever
$p\geq\frac{p_{0}}{p_{0}-1}\approx2.18.$ The number $p_{0}\in(1,2)$ is the
unique real number satisfying \[ \Gamma\left(\frac{p_{0}+1}{2}\right)
=\frac{\sqrt{\pi}}{2}. \] In the remaining case, i.e., for
$2<p<\frac{p_{0}}{p_{0}-1}\approx 2.18,$ we obtain almost optimal constants,
with better precision than $4\cdot10^{-4}$. This last result extends a result
from Diniz et al. giving the sharp constant of the famous Littlewood's $4/3$
theorem for real scalars.
| [
"math.NT",
"math.FA"
] | math.NT | math.FA | Number Theory;Functional Analysis | 4,981Number Theory;Functional Analysis
|
2007.13699 | The growth in online goods delivery is causing a dramatic surge in urban
vehicle traffic from last-mile deliveries. On the other hand, ride-sharing has
been on the rise with the success of ride-sharing platforms and increased
research on using autonomous vehicle technologies for routing and matching. The
future of urban mobility for passengers and goods relies on leveraging new
methods that minimize operational costs and environmental footprints of
transportation systems.
This paper considers combining passenger transportation with goods delivery
to improve vehicle-based transportation. Even though the problem has been
studied with a defined dynamics model of the transportation system environment,
this paper considers a model-free approach that has been demonstrated to be
adaptable to new or erratic environment dynamics. We propose FlexPool, a
distributed model-free deep reinforcement learning algorithm that jointly
serves passengers & goods workloads by learning optimal dispatch policies from
its interaction with the environment. The proposed algorithm pools passengers
for a ride-sharing service and delivers goods using a multi-hop transit method.
These flexibilities decrease the fleet's operational cost and environmental
footprint while maintaining service levels for passengers and goods. Through
simulations on a realistic multi-agent urban mobility platform, we demonstrate
that FlexPool outperforms other model-free settings in serving the demands from
passengers & goods. FlexPool achieves 30% higher fleet utilization and 35%
higher fuel efficiency in comparison to (i) model-free approaches where
vehicles transport a combination of passengers & goods without the use of
multi-hop transit, and (ii) model-free approaches where vehicles exclusively
transport either passengers or goods.
| [
"cs.AI",
"cs.LG",
"cs.MA",
"cs.SY",
"eess.SY"
] | cs.AI | cs.LG | Artificial Intelligence;Machine Learning;Multiagent Systems;Systems and Control;Systems and Control | 7,267longtail
|
2005.09765 | We investigate the presence of vortex configurations in generalized
Maxwell-Chern-Simons models with nonminimal coupling, in which we introduce a
function that modifies the dynamical term of the scalar field in the
Lagrangian. We first follow a route already considered in previous works to
develop the Bogomol'nyi procedure, and, in this context, we use the first order
equations to obtain a vortex with a novel behavior at its core. We then go
further and introduce a novel procedure to develop the Bogomol'nyi methodology.
It supports distinct first order equations, and we then investigate another
model, in which the vortex may engender inversion of the magnetic flux, an
effect with no precedents in the study of vortices within the nonminimal
context.
| [
"hep-th"
] | hep-th | High Energy Physics - Theory | 3,266High Energy Physics - Theory
|
|
0908.3640 | We report on a search for new wide halo binary stars in SDSS Stripe 82. A
list of new halo wide binary candidates which satisfy common proper motion and
photometric constraints is provided. The projected separations of the sample
lie between 0.007-0.25pc. Although the sample is not large enough to improve
constraints on dark matter in the halo, we find the wide binary angular
separation function is broadly consistent with past work. We discuss the
significance of the new sample for a number of astrophysical applications,
including as a testbed for ideas about wide binary formation. For the subset of
candidates which have radial velocity information we make use of integrals of
motion to investigate one such scheme in which the origin of Galactic wide
binaries is associated with the accretion/disruption of stellar systems in the
Galaxy. Additional spectroscopic observations of these candidate binaries will
strengthen their usefulness in many of these respects. Based on our search
experience in Stripe 82 we estimate that the upcoming Pan-STARRS survey will
increase the sample size of wide halo binaries by over an order of magnitude.
| [
"astro-ph.GA"
] | astro-ph.GA | Astrophysics of Galaxies | 464Astrophysics of Galaxies
|
|
1407.3489 | First we study in detail the tensorization properties of weak gradients in
metric measure spaces $(X,d,m)$. Then, we compare potentially different notions
of Sobolev space $H^{1,1}(X,d,m)$ and of weak gradient with exponent 1.
Eventually we apply these results to compare the area functional
$\int\sqrt{1+|\nabla f|_w^2}\,dm$ with the perimeter of the subgraph of $f$, in
the same spirit as the classical theory.
| [
"math.FA"
] | math.FA | Functional Analysis | 2,549Functional Analysis
|
|
1812.04326 | Let R be a Dedekind domain, and let G be a simply connected
Chevalley-Demazure group scheme of rank =>2. We prove that
G(R[x_1,...,x_n])=G(R)E(R[x_1,...,x_n]) for any n=>1. This extends the
corresponding results of A. Suslin and F. Grunewald, J. Mennicke, and L.
Vaserstein for G=SL_n, Sp_2n. We also deduce some corollaries of the above
result for regular rings R of higher dimension and discrete Hodge algebras over
R.
| [
"math.KT",
"math.GR"
] | math.KT | math.GR | K-Theory and Homology;Group Theory | 3,792K-Theory and Homology;Group Theory
|
2105.07040 | The results of speckle interferometric observations at the 4.1 m Southern
Astrophysical Research Telescope (SOAR) in 2020, as well as earlier unpublished
data, are given, totaling 1735 measurements of 1288 resolved pairs and
non-resolutions of 1177 targets. We resolved for the first time 59 new pairs or
subsystems in known binaries, mostly among nearby dwarf stars. This work
continues our long-term speckle program. Its main goal is to monitor orbital
motion of close binaries, including members of high-order hierarchies and
Hipparcos pairs in the solar neighborhood. We also report observations of 892
members of young moving groups and associations, where we resolved 103 new
pairs.
| [
"astro-ph.SR"
] | astro-ph.SR | Solar and Stellar Astrophysics | 6,668Solar and Stellar Astrophysics
|
|
1804.02439 | We show that the (typical) quantitative considerations about proper (as too
big) and small classes are just tangential facts regarding the consistency of
Zermelo-Fraenkel Set Theory with Choice. Effectively, we will construct a
first-order logic theory D-ZFC (Dual theory of ZFC) strictly based on (a
particular sub-collection of) proper classes with a corresponding special
membership relation, such that ZFC and D-ZFC are meta-isomorphic frameworks
(together with a more general dualization theorem). More specifically, for any
standard formal definition, axiom and theorem that can be described and deduced
in ZFC, there exists a corresponding `dual' version in D-ZFC and vice versa.
Finally, we prove the meta-fact that (classic) mathematics (i.e. theories
grounded on ZFC) and dathematics (i.e. dual theories grounded on D-ZFC) are
meta-isomorphic. This shows that proper classes are as suitable (primitive
notions) as sets for building a foundational framework for mathematics.
| [
"math.LO"
] | math.LO | Logic | 3,800Logic
|
|
1509.08915 | We consider cosmological solutions to general relativity with a single
barotropic fluid, where the pressure is a general function of the density, $p =
f(\rho)$. We derive conditions for static and oscillating solutions and provide
examples, extending earlier work to these simpler and more general single-fluid
cosmologies. Generically we expect such solutions to suffer from instabilities,
through effects such as quantum fluctuations or tunneling to zero size. We also
find a classical instability ("no-go" theorem) for oscillating solutions of a
single barotropic perfect fluid due to a necessarily negative squared sound
speed.
| [
"hep-th",
"astro-ph.CO",
"gr-qc"
] | hep-th | astro-ph.CO | High Energy Physics - Theory;Cosmology and Nongalactic Astrophysics;General Relativity and Quantum Cosmology | 3,306High Energy Physics - Theory;Cosmology and Nongalactic Astrophysics;General Relativity and Quantum Cosmology
|
0704.3108 | An interplanetary (IP) type-II-like radio burst is analyzed. It occurred on
2003 June 17-18 in association with a fast halo coronal mass ejection (CME), an
M6.8 soft-X-ray (SXR) flare, and produced a solar proton event. Unlike coronal
type II bursts and the ma jority of IP type II radio emissions, the IP
type-II-like event associated with the fast halo CME on June 17-18 varies
smoothly in time and frequency and has a frequency bandwidth that is several
times larger than is typical for coronal and IP type II emissions. Moreover,
the frequency change with time is inconsistent with that expected from plasma
radiation associated with a CME-driven shock. I suggest that this IP
type-II-like event, referred to here as an IP type II-S event, is not due to
plasma radiation but, rather, incoherent synchrotron radiation from
near-relativistic electrons entrained in the CME magnetic field, or in the
sheath region between the shock and the CME driver. This event may be an
example of a new and distinct class of interplanetary radio phenomenon.
| [
"astro-ph"
] | astro-ph | Astrophysics | 463Astrophysics
|
|
1508.06584 | Despite many nice properties and numerous achievements, general relativity is
not a complete theory. One of actual approaches towards more complete theory of
gravity is its nonlocal modification. We present here a brief review of
nonlocal gravity with its cosmological solutions. In particular, we pay special
attention to two nonlocal models and their nonsingular bounce solutions for the
cosmic scale factor.
| [
"gr-qc",
"astro-ph.CO",
"hep-th"
] | gr-qc | astro-ph.CO | General Relativity and Quantum Cosmology;Cosmology and Nongalactic Astrophysics;High Energy Physics - Theory | 2,713General Relativity and Quantum Cosmology;Cosmology and Nongalactic Astrophysics;High Energy Physics - Theory
|
2204.01771 | We study a quantum Hot Big Bang in the connection representation, with a
matter constant of motion m whose conjugate defines time. Superpositions in m
induce a unitary inner product. The wavefunction reveals a resolution of the
singularity problem without new physics or supplementary boundary conditions.
Backtracking in time, the probability peak eventually halts at a maximum
curvature, its height dropping thereafter while a symmetric contracting peak
rises. The Big Bang is replaced by a superposition of contracting and expanding
regular Universes. We contrast these findings with the situation in the metric
representation, where boundary conditions at the singularity are needed for
unitary evolution.
| [
"hep-th",
"gr-qc"
] | hep-th | gr-qc | High Energy Physics - Theory;General Relativity and Quantum Cosmology | 3,321High Energy Physics - Theory;General Relativity and Quantum Cosmology
|
gr-qc/9806070 | We study in the physical frame the phenomenon of spontaneous scalarization
that occurs in scalar-tensor theories of gravity for compact objects. We
discuss the fact that the phenomenon occurs exactly in the regime where the
Newtonian analysis indicates it should not. Finally we discuss the way the
phenomenon depends on the equation of state used to describe the nuclear
matter.
| [
"gr-qc"
] | gr-qc | General Relativity and Quantum Cosmology | 2,674General Relativity and Quantum Cosmology
|
|
math/9202209 | Circle maps with a flat spot are studied which are differentiable, even on
the boundary of the flat spot. Estimates on the Lebesgue measure and the
Hausdorff dimension of the non-wandering set are obtained. Also, a sharp
transition is found from degenerate geometry similar to what was found earlier
for non-differentiable maps with a flat spot to bounded geometry as in critical
maps without a flat spot.
| [
"math.DS"
] | math.DS | Dynamical Systems | 2,265Dynamical Systems
|
|
nucl-th/9708005 | Several methods for the treatment of pion photoproduction in the region of
the Delta(1232) resonance are discussed, in particular the effective Lagrangian
approach and the speed plot analysis are compared to a dynamical treatment. As
a main topic, we discuss the extraction of the genuine resonance parts of the
magnetic dipole and electric quadrupole multipoles of the electromagnetic
excitation of the resonance. To this end, we try to relate the various values
for the ratio R_{EM} of the E2 to M1 multipole excitation strengths for the
Delta(1232) resonance as extracted by the different methods to corresponding
ratios of a dynamical model. Moreover, it is confirmed that all methods for
extracting resonance properties suffer from an unitary ambiguity which is due
to some phenomenological contributions entering the models.
| [
"nucl-th"
] | nucl-th | Nuclear Theory | 4,876Nuclear Theory
|
|
1805.05431 | Electricity is bought and sold in wholesale markets at prices that fluctuate
significantly. Short-term forecasting of electricity prices is an important
endeavor because it helps electric utilities control risk and because it
influences competitive strategy for generators. As the "smart grid" grows,
short-term price forecasts are becoming an important input to bidding and
control algorithms for battery operators and demand response aggregators. While
the statistics and machine learning literature offers many proposed methods for
electricity price prediction, there is no consensus supporting a single best
approach. We test two contrasting machine learning approaches for predicting
electricity prices, regression decision trees and recurrent neural networks
(RNNs), and compare them to a more traditional ARIMA implementation. We conduct
the analysis on a challenging dataset of electricity prices from ERCOT, in
Texas, where price fluctuation is especially high. We find that regression
decision trees in particular achieves high performance compared to the other
methods, suggesting that regression trees should be more carefully considered
for electricity price forecasting.
| [
"cs.CY",
"cs.LG",
"stat.ML"
] | cs.CY | cs.LG | Computers and Society;Machine Learning;Machine Learning | 1,681Computers and Society;Machine Learning;Machine Learning
|
2009.09800 | Given a large number of online services on the Internet, from time to time,
people are still struggling to find out the services that they need. On the
other hand, when there are considerable research and development on service
discovery and service recommendation, most of the related work are centralized
and thus suffers inherent shortages of the centralized systems, e.g.,
adv-driven, lack at trust, transparence and fairness. In this paper, we propose
a ServiceNet - a peer-to-peer (P2P) service network for service discovery and
service recommendation. ServiceNet is inspired by blockchain technology and
aims at providing an open, transparent and self-growth, and self-management
service ecosystem. The paper will present the basic idea, an architecture
design of the prototype, and an initial implementation and performance
evaluation the prototype design.
| [
"cs.DC",
"cs.CR"
] | cs.DC | cs.CR | Distributed, Parallel, and Cluster Computing;Cryptography and Security | 2,209Distributed, Parallel, and Cluster Computing;Cryptography and Security
|
2211.11736 | In recent years, much progress has been made in learning robotic manipulation
policies that follow natural language instructions. Such methods typically
learn from corpora of robot-language data that was either collected with
specific tasks in mind or expensively re-labelled by humans with rich language
descriptions in hindsight. Recently, large-scale pretrained vision-language
models (VLMs) like CLIP or ViLD have been applied to robotics for learning
representations and scene descriptors. Can these pretrained models serve as
automatic labelers for robot data, effectively importing Internet-scale
knowledge into existing datasets to make them useful even for tasks that are
not reflected in their ground truth annotations? To accomplish this, we
introduce Data-driven Instruction Augmentation for Language-conditioned control
(DIAL): we utilize semi-supervised language labels leveraging the semantic
understanding of CLIP to propagate knowledge onto large datasets of unlabelled
demonstration data and then train language-conditioned policies on the
augmented datasets. This method enables cheaper acquisition of useful language
descriptions compared to expensive human labels, allowing for more efficient
label coverage of large-scale datasets. We apply DIAL to a challenging
real-world robotic manipulation domain where 96.5% of the 80,000 demonstrations
do not contain crowd-sourced language annotations. DIAL enables imitation
learning policies to acquire new capabilities and generalize to 60 novel
instructions unseen in the original dataset.
| [
"cs.RO",
"cs.AI",
"cs.LG"
] | cs.RO | cs.AI | Robotics;Artificial Intelligence;Machine Learning | 6,340Robotics;Artificial Intelligence;Machine Learning
|
1204.2619 | Rapidly rotating nuclei provide us good testing grounds to study the pairing
correlations; in fact, the transition from the superfluid to the normal phase
is realized at high-spin states. The role played by the pairing correlations is
quite different in these two phases: The static (BCS like mean-field)
contribution is dominant in the superfluid phase, while the dynamic
fluctuations beyond the mean-field approximation are important in the normal
phase. The influence of the pairing fluctuations on the high-spin rotational
spectra and moments of inertia is discussed.
| [
"nucl-th",
"nucl-ex"
] | nucl-th | nucl-ex | Nuclear Theory;Nuclear Experiment | 4,924Nuclear Theory;Nuclear Experiment
|
2110.06451 | In this paper, we present a novel maximum entropy formulation of the
Differential Dynamic Programming algorithm and derive two variants using
unimodal and multimodal value functions parameterizations. By combining the
maximum entropy Bellman equations with a particular approximation of the cost
function, we are able to obtain a new formulation of Differential Dynamic
Programming which is able to escape from local minima via exploration with a
multimodal policy. To demonstrate the efficacy of the proposed algorithm, we
provide experimental results using four systems on tasks that are represented
by cost functions with multiple local minima and compare them against vanilla
Differential Dynamic Programming. Furthermore, we discuss connections with
previous work on the linearly solvable stochastic control framework and its
extensions in relation to compositionality.
| [
"math.OC",
"cs.RO"
] | math.OC | cs.RO | Optimization and Control;Robotics | 5,339Optimization and Control;Robotics
|
astro-ph/9712103 | The recent confirmation that at least some gamma-ray bursters (GRBs) are
indeed at cosmological distances raises the possibility that observations of
these could provide interesting constraints on the fundamental laws of physics.
Here we demonstrate that the fine-scale time structure and hard spectra of GRB
emissions are very sensitive to the possible dispersion of electromagnetic
waves in vacuo with velocity differences $\delta v \sim E/E_{\QG}$, as
suggested in some approaches to quantum gravity. A simple estimate shows that
GRB measurements might be sensitive to a dispersion scale $E_{QG}$ comparable
to the Planck energy scale $E_{P} \sim 10^{19}$ GeV, sufficient to test some of
these theories, and we outline aspects of an observational programme that could
address this goal.
| [
"astro-ph",
"gr-qc",
"hep-ph"
] | astro-ph | gr-qc | Astrophysics;General Relativity and Quantum Cosmology;High Energy Physics - Phenomenology | 518Astrophysics;General Relativity and Quantum Cosmology;High Energy Physics - Phenomenology
|
1405.3649 | We consider a special symmetric matrix and obtain a similar formula as the
one obtained by Weyl's criterion. Some applications of the formula are given,
where we give a new way to calculate the integral of $\ln\Gamma(x)$ on $[0,1]$,
and we claim that one class of matrices are not Hadamard matrices.
| [
"math.CA"
] | math.CA | Classical Analysis and ODEs | 934Classical Analysis and ODEs
|
|
1104.3188 | We suggest a thick braneworld model in the squared curvature gravity theory.
Despite the appearance of higher order derivatives, the localization of gravity
and various bulk matter fields is shown to be possible. The existence of the
normalizable gravitational zero mode indicates that our four-dimensional
gravity is reproduced. In order to localize the chiral fermions on the brane,
two types of coupling between the fermions and the brane forming scalar is
introduced. The first coupling leads us to a Schr\"odinger equation with a
volcano potential, and the other a P\"oschl-Teller potential. In both cases,
the zero mode exists only for the left-hand fermions. Several massive KK states
of the fermions can be trapped on the brane, either as resonant states or as
bound states.
| [
"hep-th",
"gr-qc"
] | hep-th | gr-qc | High Energy Physics - Theory;General Relativity and Quantum Cosmology | 3,321High Energy Physics - Theory;General Relativity and Quantum Cosmology
|
1406.6204 | The density of states and the band diagrams were computed for diamond, cubic
boron nitrde (cBN), and hexagonal boron nitride (hBN) using a
Korringa-Kohn-Rostoker (KKR) scheme to investigate the shift of the Fermi level
by impurity-atom doping below 10 at.%. The dopant atoms were B and N for
diamond, Be, Si, and C for cBN, and Be and C for hBN. It was found that the
Fermi level was located at the valence band maximum or the conduction band
minimum in the following seven cases: (i) the B concentration was 0.3 at.% in
B-doped diamond, (ii) the N concentration was 0.4 at.% in N-doped diamond,
(iii) the concentration of Be substituting B was 0.9 at.% in cBN, (iv) the
concentration of Si substituting B was 0.3 at.% in cBN, (v) the concentration
of C substituting B was 0.3 at.% in cBN, (vi) the concentration of C
substituting N was 0.9 at.% in cBN, and (vii) the concentration of Be
substituting B was ~2 at.% in hBN. Each of these values indicates the critical
dopant concentration for semiconductor-to-metal transition. In B-doped diamond,
it serves a measure for the occurrence of superconductivity at low temperature.
| [
"cond-mat.mtrl-sci"
] | cond-mat.mtrl-sci | Materials Science | 4,287Materials Science
|
|
1306.3090 | The surface tension of quark matter plays a crucial role for the possibility
of quark matter nucleation during the formation of compact stellar objects and
also for the existence of a mixed phase within hybrid stars. However, despite
its importance, this quantity does not have a well established numerical value.
Some early estimates have predicted that, at zero temperature, the value falls
within the wide range $\gamma_0\approx10-300{\rm\ MeV/fm^2}$ but, very
recently, different model applications have reduced these numerical values to
fall within the range $\gamma_0\approx5-30{\rm\ MeV/fm^2}$ which would favor
the phase conversion process as well as the appearance of a mixed phase in
hybrid stars. In magnetars one should also account for the presence of very
high magnetic fields which may reach up to about $ eB\approx 3-30\, m_\pi^2$
($B \approx 10^{19}-10^{20} \,G$) at the core of the star so that it may also
be important to analyze how the presence of a magnetic field affects the
surface tension. With this aim we consider magnetized two flavor quark matter,
described by the Nambu--Jona-Lasinio model. We show that although the surface
tension oscillates around its B=0 value, when $0 < eB \lesssim 10 \, m_\pi^2$,
it only reaches values which are still relatively small. For $eB \approx 5\,
m_\pi^2$ the B=0 surface tension value drops by about 30% while for $eB \gtrsim
10\, m_\pi^2$ it quickly raises with the field intensity so that the phase
conversion and the presence of a mixed phase should be suppressed if extremely
high fields are present. We also investigate how thermal effects influence the
surface tension for magnetized quark matter.
| [
"hep-ph",
"astro-ph.HE",
"nucl-th"
] | hep-ph | astro-ph.HE | High Energy Physics - Phenomenology;High Energy Astrophysical Phenomena;Nuclear Theory | 3,195High Energy Physics - Phenomenology;High Energy Astrophysical Phenomena;Nuclear Theory
|
2102.09710 | There is growing interest in mining software repository data to understand,
and predict, various aspects of team processes. In particular, text mining and
natural-language processing (NLP) techniques have supported such efforts.
Visualization may also supplement text mining to reveal unique
multi-dimensional insights into software teams' behavioral processes. We
demonstrate the utility of combining these approaches in this study. Future
application of these methods to the study of teams' behavioral processes offers
promise for both research and practice.
| [
"cs.SE"
] | cs.SE | Software Engineering | 6,626Software Engineering
|
|
2106.13438 | Hall instability in electron magnetohydrodynamics is interpreted as the
shear-Hall instability driven jointly by helicoidal oscillations and shear in
the electron current velocity. This explanation suggests an antiparallel
orientation of the background magnetic field and vorticity of the current
velocity as the necessary condition for Hall instability. The condition is
tested and generally confirmed by numerical computations in plane slab
geometry. Unstable eigenmodes are localized in the spatial regions of the
antiparallel field and vorticity. Computations of the tearing-type mode of the
instability are complemented by (and generally agree with) asymptotic
analytical estimations for large Hall numbers. The stabilizing effect of
perfect conductor boundary conditions is found and explained. For large Hall
numbers, the growth rates approach the power law dependence $\sigma \propto
B^\alpha\eta^{1-\alpha}$ on the magnetic field ($B$) and diffusivity ($\eta$).
Almost all computations give the power index $\alpha = 3/4$ with one exception
of the tearing-type mode with vacuum boundary conditions for which case $\alpha
= 2/3$.
| [
"physics.plasm-ph"
] | physics.plasm-ph | Plasma Physics | 5,556Plasma Physics
|
|
1003.1158 | We develop the theory of Weyl group multiple Dirichlet series for root
systems of type C. For an arbitrary root system of rank r and a positive
integer n, these are Dirichlet series in r complex variables with analytic
continuation and functional equations isomorphic to the associated Weyl group.
In type C, they conjecturally arise from the Fourier-Whittaker coefficients of
minimal parabolic Eisenstein series on an n-fold metaplectic cover of SO(2r+1).
For any odd n, we construct an infinite family of Dirichlet series
conjecturally satisfying the above analytic properties. The coefficients of
these series are exponential sums built from Gelfand-Tsetlin bases of certain
highest weight representations. Previous attempts to define such series by
Brubaker, Bump, and Friedberg in [6] and [7] required n to be sufficiently
large, so that coefficients could be described by Weyl group orbits. We
demonstrate that our construction agrees with that of [6] and [7] in the case
where both series are defined, and hence inherits the desired analytic
properties for n sufficiently large. Moreover our construction is valid even
for n=1, where we prove our series is a Whittaker coefficient of an Eisenstein
series. This requires the Casselman-Shalika formula for unramified principal
series and a remarkable deformation of the Weyl character formula of Hamel and
King [20].
| [
"math.NT",
"math.RT"
] | math.NT | math.RT | Number Theory;Representation Theory | 4,998Number Theory;Representation Theory
|
2001.02674 | Encoder-decoder based sequence-to-sequence models have demonstrated
state-of-the-art results in end-to-end automatic speech recognition (ASR).
Recently, the transformer architecture, which uses self-attention to model
temporal context information, has been shown to achieve significantly lower
word error rates (WERs) compared to recurrent neural network (RNN) based system
architectures. Despite its success, the practical usage is limited to offline
ASR tasks, since encoder-decoder architectures typically require an entire
speech utterance as input. In this work, we propose a transformer based
end-to-end ASR system for streaming ASR, where an output must be generated
shortly after each spoken word. To achieve this, we apply time-restricted
self-attention for the encoder and triggered attention for the encoder-decoder
attention mechanism. Our proposed streaming transformer architecture achieves
2.8% and 7.2% WER for the "clean" and "other" test data of LibriSpeech, which
to our knowledge is the best published streaming end-to-end ASR result for this
task.
| [
"cs.SD",
"cs.CL",
"cs.LG",
"eess.AS",
"stat.ML"
] | cs.SD | cs.CL | Sound;Computation and Language;Machine Learning;Audio and Speech Processing;Machine Learning | 7,267longtail
|
2104.06537 | We give an explicit description of the generator of finitely presented
objects of the coslice of a locally finitely presentable category under a given
object, as consisting of all pushouts of finitely presented maps under this
object. Then we prove that the comma category under the direct image part of a
morphism of locally finitely presentable category is still locally finitely
presentable, and we give again an explicit description of its generator of
finitely presented objects. We finally deduce that 2-category $\LFP$ has comma
objects computed in $\Cat$.
| [
"math.CT"
] | math.CT | Category Theory | 757Category Theory
|
|
2211.04237 | In this paper, we consider a system of equations arising from the
$\text{U}(1)\times \text{U}(1)$ Abelian Chern-Simons model
\begin{eqnarray*}\left\{\begin{aligned} \Delta u
&=\lambda\left(a(b-a)\mathrm{e}^u-b(b-a)\mathrm{e}^{\upsilon}+a^2\mathrm{e}^{2u}-ab\mathrm{e}^{2\upsilon}+b(b-a)\mathrm{e}^{u+\upsilon}
\right)+4\pi\sum\limits_{j=1}^{k_1}m_j\delta_{p_j},\\ \Delta
\upsilon&=\lambda\left(-b(b-a)\mathrm{e}^u+a(b-a)\mathrm{e}^{\upsilon}-ab\mathrm{e}^{2u}+a^2\mathrm{e}^{2\upsilon}+b(b-a)\mathrm{e}^{u+\upsilon}
\right)+4\pi\sum\limits_{j=1}^{k_2}n_j\delta_{q_j}, \end{aligned} \right.
\end{eqnarray*} on finite graphs. Here $\lambda>0$, $b>a>0$, $m_j>0\,
(j=1,2,\cdot\cdot\cdot,k_1)$, $n_j>0\,(j=1,2,\cdot\cdot\cdot,k_2)$,
$\delta_{p}$ is the Dirac delta mass at vertex $p$.
We establish the iteration scheme and prove existence of solutions. We also
develop a new method to get the asymptotic behaviors of solutions as $\lambda$
goes to infinity. This method is also applicable to the Chern-Simons system
$$\left\{\begin{aligned} \Delta u
&=\lambda\mathrm{e}^{\upsilon}(\mathrm{e}^{u}-1)
+4\pi\sum\limits_{j=1}^{k_1}m_j\delta_{p_j},\\ \Delta
\upsilon&=\lambda\mathrm{e}^{u}(\mathrm{e}^{\upsilon}-1)+4\pi\sum\limits_{j=1}^{k_2}n_j\delta_{q_j},
\end{aligned} \right. $$ and the classical Chern-Simons equation $$ \Delta
u=\lambda \mathrm{e}^u(\mathrm{e}^u-1)+4\pi\sum\limits_{j=1}^{N}\delta_{p_j}.$$
| [
"math.AP"
] | math.AP | Analysis of PDEs | 205Analysis of PDEs
|
|
1902.00134 | The discovery of the Higgs boson in 2012, by the ATLAS and CMS experiments,
was a success achieved with only a percent of the entire dataset foreseen for
the LHC. It opened a landscape of possibilities in the study of Higgs boson
properties, Electroweak Symmetry breaking and the Standard Model in general, as
well as new avenues in probing new physics beyond the Standard Model. Six years
after the discovery, with a conspicuously larger dataset collected during LHC
Run 2 at a 13 TeV centre-of-mass energy, the theory and experimental particle
physics communities have started a meticulous exploration of the potential for
precision measurements of its properties. This includes studies of Higgs boson
production and decays processes, the search for rare decays and production
modes, high energy observables, and searches for an extended electroweak
symmetry breaking sector. This report summarises the potential reach and
opportunities in Higgs physics during the High Luminosity phase of the LHC,
with an expected dataset of pp collisions at 14 TeV, corresponding to an
integrated luminosity of 3 ab$^{-1}$. These studies are performed in light of
the most recent analyses from LHC collaborations and the latest theoretical
developments. The potential of an LHC upgrade, colliding protons at a
centre-of-mass energy of 27 TeV and producing a dataset corresponding to an
integrated luminosity of 15 ab$^{-1}$, is also discussed.
| [
"hep-ph",
"hep-ex"
] | hep-ph | hep-ex | High Energy Physics - Phenomenology;High Energy Physics - Experiment | 3,198High Energy Physics - Phenomenology;High Energy Physics - Experiment
|
hep-th/0702181 | The massive spin-2 quantum gauge theory previously developed is applied to
calculate gravitational bremsstrahlung. It is shown that this theory is unique
and free from defects. In particular, there is no strong coupling if the
graviton mass becomes small. The cross sections go over smoothly into the ones
of the massless theory in the limit of vanishing graviton mass. The massless
cross sections are calculated for the full tensor theory.
| [
"hep-th"
] | hep-th | High Energy Physics - Theory | 3,266High Energy Physics - Theory
|
|
hep-ex/9603008 | Preliminary results on a measurement of the proton structure function F_2 are
reported for momentum transfers squared Q^2 between 1.5~GeV^2 and 5000 GeV^2
and for Bjorken x between 5.10^{-5} and 0.32 using data collected by the HERA
experiments H1 and ZEUS in 1994. F_2 increases significantly with decreasing x,
even in the lowest reachable Q^2 region. The data are well described by a Next
to Leading Order QCD fit, and support within the present precision that the
rise at low x within this Q^2 range is generated "radiatively" via the DGLAP
evolution equations. Prospects for future structure function measurements at
HERA are briefly mentioned.
| [
"hep-ex"
] | hep-ex | High Energy Physics - Experiment | 3,059High Energy Physics - Experiment
|
|
2010.11559 | We consider the problem of learning a graph under the Laplacian constraint
with a non-convex penalty: minimax concave penalty (MCP). For solving the MCP
penalized graphical model, we design an inexact proximal difference-of-convex
algorithm (DCA) and prove its convergence to critical points. We note that each
subproblem of the proximal DCA enjoys the nice property that the objective
function in its dual problem is continuously differentiable with a semismooth
gradient. Therefore, we apply an efficient semismooth Newton method to
subproblems of the proximal DCA. Numerical experiments on various synthetic and
real data sets demonstrate the effectiveness of the non-convex penalty MCP in
promoting sparsity. Compared with the existing state-of-the-art method, our
method is demonstrated to be more efficient and reliable for learning graph
Laplacian with MCP.
| [
"cs.LG",
"math.OC"
] | cs.LG | math.OC | Machine Learning;Optimization and Control | 4,235Machine Learning;Optimization and Control
|
2101.12631 | Approximate nearest neighbor search (ANNS) constitutes an important operation
in a multitude of applications, including recommendation systems, information
retrieval, and pattern recognition. In the past decade, graph-based ANNS
algorithms have been the leading paradigm in this domain, with dozens of
graph-based ANNS algorithms proposed. Such algorithms aim to provide effective,
efficient solutions for retrieving the nearest neighbors for a given query.
Nevertheless, these efforts focus on developing and optimizing algorithms with
different approaches, so there is a real need for a comprehensive survey about
the approaches' relative performance, strengths, and pitfalls. Thus here we
provide a thorough comparative analysis and experimental evaluation of 13
representative graph-based ANNS algorithms via a new taxonomy and fine-grained
pipeline. We compared each algorithm in a uniform test environment on eight
real-world datasets and 12 synthetic datasets with varying sizes and
characteristics. Our study yields novel discoveries, offerings several useful
principles to improve algorithms, thus designing an optimized method that
outperforms the state-of-the-art algorithms. This effort also helped us
pinpoint algorithms' working portions, along with rule-of-thumb recommendations
about promising research directions and suitable algorithms for practitioners
in different fields.
| [
"cs.IR",
"cs.DB"
] | cs.IR | cs.DB | Information Retrieval;Databases | 3,603Information Retrieval;Databases
|
1809.08010 | First-principles calculations of work function tuning induced by different
chemical terminations on Si(100) surface are presented and discussed. We find
that the presence of halogen atoms (I, Br, Cl, and F) leads to an increase of
the work function if compared to the fully hydrogenated surface. This is a
quite general effect and is directly linked to the chemisorbed atoms
electronegativity as well as to the charge redistribution at the interface. All
these results are examined with respect to previous theoretical works and
experimental data obtained for the (100) as well as other Si surface
orientations. Based on this analysis, we argue that the changes in the
electronic properties caused by variations of the interfacial chemistry
strongly depend on the chemisorbed species and much less on the surface crystal
orientation.
| [
"cond-mat.mtrl-sci"
] | cond-mat.mtrl-sci | Materials Science | 4,287Materials Science
|
|
2203.00189 | Quantum metrology exploits quantum resources and strategies to improve
measurement precision of unknown parameters. One crucial issue is how to
prepare a quantum entangled state suitable for high-precision measurement
beyond the standard quantum limit. Here, we propose a scheme to find optimal
pulse sequence to accelerate the one-axis twisting dynamics for entanglement
generation with the aid of deep reinforcement learning (DRL). We consider the
pulse train as a sequence of $\pi/2$ pulses along one axis or two orthogonal
axes, and the operation is determined by maximizing the quantum Fisher
information using DRL. Within a limited evolution time, the ultimate precision
bounds of the prepared entangled states follow the Heisenberg-limited scalings.
These states can also be used as the input states for Ramsey interferometry and
the final measurement precisions still follow the Heisenberg-limited scalings.
While the pulse train along only one axis is more simple and efficient, the
scheme using pulse sequence along two orthogonal axes show better robustness
against atom number deviation. Our protocol with DRL is efficient and easy to
be implemented in state-of-the-art experiments.
| [
"quant-ph"
] | quant-ph | Quantum Physics | 5,985Quantum Physics
|
|
1708.04355 | Only five binary systems have been found to emit at TeV energies. Each of
these systems is composed of a massive O or B type star and a compact object
(black hole or a pulsar). The type of compact object and the origin of the
gamma-ray emission is unknown for most of these systems. Extending spectral
observations to higher energies can help disentangle the nature of the compact
object as well as the particle acceleration mechanisms present. Interestingly,
the TeV emission from these systems does not always coincide with their
emission in GeV or X-ray, which is how many such systems have been originally
discovered. Increased coverage of these systems may allow HAWC to see precisely
when in the orbit the TeV emission begins and ends. The HAWC Observatory
detects TeV gamma-rays with high sensitivity, covering over two-thirds of the
overhead sky every day. Applying a stacking method to known TeV binary systems
can help HAWC enhance the signal from TeV binaries above the steady background
from other sources in the galaxy. We will present results from this stacking
analysis using 760 days of HAWC data.
| [
"astro-ph.HE",
"hep-ex"
] | astro-ph.HE | hep-ex | High Energy Astrophysical Phenomena;High Energy Physics - Experiment | 3,029High Energy Astrophysical Phenomena;High Energy Physics - Experiment
|
1805.11799 | This work explores the application of deep learning, a machine learning
technique that uses deep neural networks (DNN) in its core, to an automated
theorem proving (ATP) problem. To this end, we construct a statistical model
which quantifies the likelihood that a proof is indeed a correct one of a given
proposition. Based on this model, we give a proof-synthesis procedure that
searches for a proof in the order of the likelihood. This procedure uses an
estimator of the likelihood of an inference rule being applied at each step of
a proof. As an implementation of the estimator, we propose a
proposition-to-proof architecture, which is a DNN tailored to the automated
proof synthesis problem. To empirically demonstrate its usefulness, we apply
our model to synthesize proofs of propositional logic. We train the
proposition-to-proof model using a training dataset of proposition-proof pairs.
The evaluation against a benchmark set shows the very high accuracy and an
improvement to the recent work of neural proof synthesis.
| [
"cs.AI",
"cs.LG",
"cs.LO",
"cs.PL"
] | cs.AI | cs.LG | Artificial Intelligence;Machine Learning;Logic in Computer Science;Programming Languages | 7,267longtail
|
2210.00149 | Cycling of carbon dioxide between the atmosphere and interior of rocky
planets can stabilize global climate and enable planetary surface temperatures
above freezing over geologic time. However, variations in global carbon budget
and unstable feedback cycles between planetary sub-systems may destabilize the
climate of rocky exoplanets toward regimes unknown in the Solar System. Here,
we perform clear-sky atmospheric radiative transfer and surface weathering
simulations to probe the stability of climate equilibria for rocky,
ocean-bearing exoplanets at instellations relevant for planetary systems in the
outer regions of the circumstellar habitable zone. Our simulations suggest that
planets orbiting G- and F-type stars (but not M-type stars) may display
bistability between an Earth-like climate state with efficient carbon
sequestration and an alternative stable climate equilibrium where CO$_2$
condenses at the surface and forms a blanket of either clathrate hydrate or
liquid CO$_2$. At increasing instellation and with ineffective weathering, the
latter state oscillates between cool, surface CO$_2$-condensing and hot,
non-condensing climates. CO$_2$ bistable climates may emerge early in planetary
history and remain stable for billions of years. The carbon dioxide-condensing
climates follow an opposite trend in $p$CO$_2$ versus instellation compared to
the weathering-stabilized planet population, suggesting the possibility of
observational discrimination between these distinct climate categories.
| [
"astro-ph.EP"
] | astro-ph.EP | Earth and Planetary Astrophysics | 2,351Earth and Planetary Astrophysics
|
|
1205.2234 | In this paper, we propose and study a new semi-random model for graph
partitioning problems. We believe that it captures many properties of
real--world instances. The model is more flexible than the semi-random model of
Feige and Kilian and planted random model of Bui, Chaudhuri, Leighton and
Sipser.
We develop a general framework for solving semi-random instances and apply it
to several problems of interest. We present constant factor bi-criteria
approximation algorithms for semi-random instances of the Balanced Cut,
Multicut, Min Uncut, Sparsest Cut and Small Set Expansion problems. We also
show how to almost recover the optimal solution if the instance satisfies an
additional expanding condition. Our algorithms work in a wider range of
parameters than most algorithms for previously studied random and semi-random
models.
Additionally, we study a new planted algebraic expander model and develop
constant factor bi-criteria approximation algorithms for graph partitioning
problems in this model.
| [
"cs.DS",
"cs.CC"
] | cs.DS | cs.CC | Data Structures and Algorithms;Computational Complexity | 1,916Data Structures and Algorithms;Computational Complexity
|
2004.08349 | Bayesian optimisation is a popular approach for optimising expensive
black-box functions. The next location to be evaluated is selected via
maximising an acquisition function that balances exploitation and exploration.
Gaussian processes, the surrogate models of choice in Bayesian optimisation,
are often used with a constant prior mean function equal to the arithmetic mean
of the observed function values. We show that the rate of convergence can
depend sensitively on the choice of mean function. We empirically investigate 8
mean functions (constant functions equal to the arithmetic mean, minimum,
median and maximum of the observed function evaluations, linear, quadratic
polynomials, random forests and RBF networks), using 10 synthetic test problems
and two real-world problems, and using the Expected Improvement and Upper
Confidence Bound acquisition functions. We find that for design dimensions
$\ge5$ using a constant mean function equal to the worst observed quality value
is consistently the best choice on the synthetic problems considered. We argue
that this worst-observed-quality function promotes exploitation leading to more
rapid convergence. However, for the real-world tasks the more complex mean
functions capable of modelling the fitness landscape may be effective, although
there is no clearly optimum choice.
| [
"cs.LG",
"stat.ML"
] | cs.LG | stat.ML | Machine Learning;Machine Learning | 4,163Machine Learning;Machine Learning
|
1302.3370 | It is well known that longer Bi-2212 conductors have significantly lower
critical current density (Jc) than shorter ones, and recently it has become
clear that a major cause of this reduction is internal gas pressure generated
during heat treatment, which expands the wire diameter and dedensifies the
Bi-2212 filaments. Here we report on the length-dependent expansion of 5 to 240
cm lengths of state-of-the-art, commercial Ag alloy-sheathed Bi-2212 wire after
full and some partial heat treatments. Detailed image analysis along the wire
length shows that the wire diameter increases with distance from the ends,
longer samples often showing evident damage and leaks provoked by the internal
gas pressure. Comparison of heat treatments carried out just below the melting
point and with the usual melt process makes it clear that melting is crucial to
developing high internal pressure. The decay of Jc away from the ends is
directly correlated to the local wire diameter increase, which decreases the
local Bi-2212 filament mass density and lowers Jc, often by well over 50%. It
is clear that control of the internal gas pressure is crucial to attaining the
full Jc of these very promising round wires and that the very variable
properties of Bi-2212 wires are due to the fact that this internal gas pressure
has so far not been well controlled.
| [
"cond-mat.supr-con"
] | cond-mat.supr-con | Superconductivity | 7,066Superconductivity
|
|
2307.06381 | The goal of the present paper is to make a numerical analysis of parametric
optimization of low thrust orbital maneuver. An orbital maneuver occurs when it
is necessary to modify the orbit a space vehicle to change its function or to
correct effects of perturbations. A parametric optimization is made when the
thrust is not free to point to any direction, but has to follow some prescribed
law, like a linear or quadratic relation with time.
| [
"astro-ph.EP",
"math.OC"
] | astro-ph.EP | math.OC | Earth and Planetary Astrophysics;Optimization and Control | 7,267longtail
|
physics/0605195 | Building on insights about the classical pathways to double ionization in
strong laser fields we here propose a 1+1-dimensional model that captures
essentials of the 3-d potential landscape and allows efficient studies of the
process in reduced dimensions. The reduction to one degree of freedom for each
electron is obtained by confining their motion to lines at an angle of pi/6
with respect to the field axis; the justification for this choice is that upon
variation of the electric field the Stark saddles move along the same lines. In
this way we obtain a low-dimensional representation in which symmetric electron
escape is possible. As a demonstration of the advantages of this model we
confirm numerically the equivalent of the Wannier threshold behaviour for
constant electric field and identify several classes of trajectories that can
contribute to the ionization process.
| [
"physics.atom-ph"
] | physics.atom-ph | Atomic Physics | 569Atomic Physics
|
|
1212.3214 | Background: Predictive, stable and interpretable gene signatures are
generally seen as an important step towards a better personalized medicine.
During the last decade various methods have been proposed for that purpose.
However, one important obstacle for making gene signatures a standard tool in
clinics is the typical low reproducibility of these signatures combined with
the difficulty to achieve a clear biological interpretation. For that purpose
in the last years there has been a growing interest in approaches that try to
integrate information from molecular interaction networks. Results: We propose
a novel algorithm, called FrSVM, which integrates protein-protein interaction
network information into gene selection for prognostic biomarker discovery. Our
method is a simple filter based approach, which focuses on central genes with
large differences in their expression. Compared to several other competing
methods our algorithm reveals a significantly better prediction performance and
higher signature stability. More- over, obtained gene lists are highly enriched
with known disease genes and drug targets. We extendd our approach further by
integrating information on candidate disease genes and targets of disease
associated Transcript Factors (TFs).
| [
"q-bio.GN",
"stat.ML"
] | q-bio.GN | stat.ML | Genomics;Machine Learning | 2,806Genomics;Machine Learning
|
1602.08645 | Force sensors are at the heart of different technologies such as atomic force
microscopy or inertial sensing \cite{RMPforce2003, Rugar2004, YazdiIEEE}. These
sensors often rely on the measurement of the displacement amplitude of
mechanical oscillators under applied force. Examples for such mechanical
oscillators include micro-fabricated cantilevers \cite{YazdiIEEE}, carbon
nanotubes \cite{NanotubeForce} as well as single trapped ions \cite{Bollinger,
Udem} . The best sensitivity is typically achieved when the force is
alternating at the mechanical resonance frequency of the oscillator thus
increasing its response by the mechanical quality factor. The measurement of
low-frequency forces, that are below resonance, is a more difficult task as the
resulting oscillation amplitudes are significantly lower. Here we use a single
trapped $^{88}Sr^{+}$ ion as a force sensor. The ion is trapped in a linear
harmonic trap, and is electrically driven at a frequency much lower than the
trap resonance frequency. To be able to measure the small amplitude of motion
we combine two powerful techniques. The force magnitude is determined by the
measured periodic Doppler shift of an atomic optical clock transition and the
Quantum Lock-in technique is used to coherently accumulate the phases acquired
during different force half-cycles. We demonstrate force detection both when
the oscillating force is phase-synchronized with the quantum lock-in sequence
and when it is asynchronous and report frequency force detection sensitivity as
low as $5.3\times10^{-19}\frac{\mathrm{N}}{\sqrt{\mathrm{Hz}}}$ .
| [
"quant-ph",
"physics.atom-ph"
] | quant-ph | physics.atom-ph | Quantum Physics;Atomic Physics | 5,996Quantum Physics;Atomic Physics
|
1602.00193 | WeChat is a mobile messaging application that has 549 million active users as
of Q1 2015, and "WeChat Moments" (WM) serves its social-networking function
that allows users to post/share links of web pages. WM differs from the other
social networks as it imposes many restrictions on the information diffusion
process to mitigate the information overload. In this paper, we conduct a
measurement study on information diffusion in the WM network by crawling and
analyzing the spreading statistics of more than 160,000 pages that involve
approximately 40 million users. Specifically, we identify the relationship of
the number of posted pages and the number of views, the diffusion path length,
the similarity and distribution of users' locations as well as their
connections with the GDP of the users' province. For each individual WM page,
we measure its temporal characteristics (e.g., the life time, the popularity
within a time period); for each individual user, we evaluate how many of, or
how likely, one's friends will view his posted pages. Our results will help the
business to decide when and how to release the marketing pages over WM for
better publicity.
| [
"cs.CY",
"cs.SI"
] | cs.CY | cs.SI | Computers and Society;Social and Information Networks | 1,692Computers and Society;Social and Information Networks
|
0809.4094 | Spin polarization of the tunnel conductivity has been studied for Fe/GaAs
junctions with Schottky barriers. It is shown that band matching of resonant
interface states within the Schottky barrier defines the sign of spin
polarization of electrons transported through the barrier. The results account
very well for experimental results including the tunneling of photo-excited
electrons, and suggest that the spin polarization (from -100% to 100%) is
dependent on the Schottky barrier height. They also suggest that the sign of
the spin polarization can be controlled with a bias voltage.
| [
"cond-mat.mes-hall"
] | cond-mat.mes-hall | Mesoscale and Nanoscale Physics | 4,450Mesoscale and Nanoscale Physics
|
|
quant-ph/0601165 | We have studied statistical properties of the values of the Wigner function
W(x) of 1D quantum maps on compact 2D phase space of finite area V. For this
purpose we have defined a Wigner function probability distribution P(w) = (1/V)
int delta(w-W(x)) dx, which has, by definition, fixed first and second moment.
In particular, we concentrate on relaxation of time evolving quantum state in
terms of W(x), starting from a coherent state. We have shown that for a
classically chaotic quantum counterpart the distribution P(w) in the
semi-classical limit becomes a Gaussian distribution that is fully determined
by the first two moments. Numerical simulations have been performed for the
quantum sawtooth map and the quantized kicked top. In a quantum system with
Hilbert space dimension N (similar 1/hbar) the transition of P(w) to a Gaussian
distribution was observed at times t proportional to log N. In addition, it has
been shown that the statistics of Wigner functions of propagator eigenstates is
Gaussian as well in the classically fully chaotic regime. We have also studied
the structure of the nodal cells of the Wigner function, in particular the
distribution of intersection points between the zero manifold and arbitrary
straight lines.
| [
"quant-ph",
"nlin.CD"
] | quant-ph | nlin.CD | Quantum Physics;Chaotic Dynamics | 6,007Quantum Physics;Chaotic Dynamics
|
2011.00870 | Texture reconstruction techniques generally suffer from the errors in
keyframe poses. We present a non-iterative method for seamless texture
reconstruction of a given 3D scene. Our method finds the best texture alignment
in a single shot using a global optimisation framework. First, we automatically
select the best keyframe to texture each face of the mesh. This leads to a
decomposition of the mesh into small groups of connected faces associated to a
same keyframe. We call such groups fragments. Then, we propose a geometry-aware
matching technique between the 3D keypoints extracted around the fragment
borders, where the matching zone is controlled by the margin size. These
constraints lead to a least squares (LS) model for finding the optimal
alignment. Finally, visual seams are further reduced by applying a fast colour
correction. In contrast to pixel-wise methods, we find the optimal alignment by
solving a sparse system of linear equations, which is very fast and
non-iterative. Experimental results demonstrate low computational complexity
and outperformance compared to other alignment methods.
| [
"cs.CV"
] | cs.CV | Computer Vision and Pattern Recognition | 1,498Computer Vision and Pattern Recognition
|
|
1304.0904 | We introduce the dual isoperimetrix which solves the isoperimetric problem in
the dual Brunn-Minkowski theory. We then show how the dual isoperimetrix is
related to the isoperimetrix from the Brunn-Minkowski theory.
| [
"math.DG"
] | math.DG | Differential Geometry | 2,010Differential Geometry
|
|
1809.04946 | It has been suggested that dark matter is a superfluid of particles whose
masses are on the rough order of $10^{-22}$ eV. Since the occupation numbers
are huge, the state is coherent, and the speeds typical of orbital velocities
in halos, it has generally been assumed that a classical effective
non-relativistic treatment is adequate. However, the Compton wavelength would
be $\sim 1\, {\rm pc}$, and around the Compton scale concerns about some
aspects of quantum measurement theory, known in principle but not
quantitatively significant in previous cases, become pronounced. I estimate
here the stress--energy operator, averaged over a few Compton wavelengths; a
rough but useful approximation has a remarkably simple form. Conventional
quantum measurement theory gives physically unacceptable results: a
thought-experiment to measure the stress--energy is described which would
involve only a modest apparatus but would excite particles in the observation
volume to relativistic energies; these particles would escape the Galaxy, and
there would be a substantial violation of energy conservation. Related
foundational questions come up: the meaning of measurements of observables with
continuous spectra, and the problem of predicting when measurements occur. The
effective classical theory of fuzzy dark matter is not affected; however, the
underlying quantum theory cannot be regarded as satisfactory without resolving
these issues. But we may interpret the results more broadly. The macroscopic
Compton scale amplifies inadequacies of measurement theory which have not
previously seemed pressing.
| [
"gr-qc",
"astro-ph.GA",
"hep-ph",
"hep-th",
"quant-ph"
] | gr-qc | astro-ph.GA | General Relativity and Quantum Cosmology;Astrophysics of Galaxies;High Energy Physics - Phenomenology;High Energy Physics - Theory;Quantum Physics | 7,267longtail
|
1308.5156 | In the present work, we analyze the corrections caused by an anomalous
dispersion relation, suggested in several quantum gravity models, upon the
speed of sound in a weakly interacting Bose--Einstein Condensate, trapped in a
potential of the form $V(r)\sim r^{2}$. We show that the corresponding ground
state energy and consequently, the associated speed of sound, present
corrections respect to the usual case, which may be used to explore the
sensitivity to Planck--scale effects on these relevant properties associated
with the condensate. Indeed, we stress that this type of macroscopic bodies may
be more sensitive, under certain conditions, to Planck--scale manifestations
than its constituents. In addition, we prove that the inclusion of a trapping
potential, together with many--body contributions, improves the sensitivity to
Planck--scale signals, compared to the homogeneous system.
| [
"gr-qc"
] | gr-qc | General Relativity and Quantum Cosmology | 2,674General Relativity and Quantum Cosmology
|
|
0911.3354 | This is a survey of several exciting recent results in which techniques
originating in the area known as additive combinatorics have been applied to
give results in other areas, such as group theory, number theory and
theoretical computer science. We begin with a discussion of the notion of an
approximate group and also that of an approximate field, describing key results
of Freiman-Ruzsa, Bourgain-Katz-Tao, Helfgott and others in which the structure
of such objects is elucidated. We then move on to the applications. In
particular we will look at the work of Bourgain and Gamburd on expansion
properties of Cayley graphs on SL_2(F_p) and at its application in the work of
Bourgain, Gamburd and Sarnak on nonlinear sieving problems.
| [
"math.NT",
"math.CO"
] | math.NT | math.CO | Number Theory;Combinatorics | 4,960Number Theory;Combinatorics
|
2308.04243 | In recent years, deep neural networks have achieved remarkable accuracy in
computer vision tasks. With inference time being a crucial factor, particularly
in dense prediction tasks such as semantic segmentation, knowledge distillation
has emerged as a successful technique for improving the accuracy of lightweight
student networks. The existing methods often neglect the information in
channels and among different classes. To overcome these limitations, this paper
proposes a novel method called Inter-Class Similarity Distillation (ICSD) for
the purpose of knowledge distillation. The proposed method transfers high-order
relations from the teacher network to the student network by independently
computing intra-class distributions for each class from network outputs. This
is followed by calculating inter-class similarity matrices for distillation
using KL divergence between distributions of each pair of classes. To further
improve the effectiveness of the proposed method, an Adaptive Loss Weighting
(ALW) training strategy is proposed. Unlike existing methods, the ALW strategy
gradually reduces the influence of the teacher network towards the end of
training process to account for errors in teacher's predictions. Extensive
experiments conducted on two well-known datasets for semantic segmentation,
Cityscapes and Pascal VOC 2012, validate the effectiveness of the proposed
method in terms of mIoU and pixel accuracy. The proposed method outperforms
most of existing knowledge distillation methods as demonstrated by both
quantitative and qualitative evaluations. Code is available at:
https://github.com/AmirMansurian/AICSD
| [
"cs.CV"
] | cs.CV | Computer Vision and Pattern Recognition | 1,498Computer Vision and Pattern Recognition
|
|
2207.12559 | In this paper, we develop four spiking neural network (SNN) models for two
static American Sign Language (ASL) hand gesture classification tasks, i.e.,
the ASL Alphabet and ASL Digits. The SNN models are deployed on Intel's
neuromorphic platform, Loihi, and then compared against equivalent deep neural
network (DNN) models deployed on an edge computing device, the Intel Neural
Compute Stick 2 (NCS2). We perform a comprehensive comparison between the two
systems in terms of accuracy, latency, power consumption, and energy. The best
DNN model achieves an accuracy of 99.93% on the ASL Alphabet dataset, whereas
the best performing SNN model has an accuracy of 99.30%. For the ASL-Digits
dataset, the best DNN model achieves an accuracy of 99.76% accuracy while the
SNN achieves 99.03%. Moreover, our obtained experimental results show that the
Loihi neuromorphic hardware implementations achieve up to 20.64x and 4.10x
reduction in power consumption and energy, respectively, when compared to NCS2.
| [
"cs.LG",
"cs.AI",
"cs.CV",
"cs.HC",
"cs.NE"
] | cs.LG | cs.AI | Machine Learning;Artificial Intelligence;Computer Vision and Pattern Recognition;Human-Computer Interaction;Neural and Evolutionary Computing | 7,267longtail
|
2007.05485 | The Kuramoto model is a canonical model for understanding phase-locking
phenomenon. It is well-understood that, in the usual mean-field scaling, full
phase-locking is unlikely and that it is partially phase-locked states that are
important in applications. Despite this, while there has been much attention
given to the existence and stability of fully phase-locked states in the finite
N Kuramoto model, the partially phase-locked states have received much less
attention. In this paper, we present two related results. Firstly, we derive an
analytical criterion that, for sufficiently strong coupling, guarantees the
existence of a partially phase-locked state by proving the existence of an
attracting ball around a fixed point of a subset of the oscillators. We also
derive a larger invariant ball such that any point in it will asymptotically
converge to the attracting ball. Secondly, we consider the large N
(thermodynamic) limit for the Kuramoto system with randomly distributed
frequencies. Using some results of De Smet and Aeyels on partial entrainment,
we derive a deterministic condition giving almost sure existence of a partially
entrained state for sufficiently strong coupling when the natural frequencies
of the individual oscillators are independent identically distributed random
variables, as well as upper and lower bounds on the size of the largest cluster
of partially entrained oscillators. Interestingly in a series on numerical
experiments we find that the observed size of the largest entrained cluster is
predicted extremely well by the upper bound.
| [
"nlin.AO",
"math.CA"
] | nlin.AO | math.CA | Adaptation and Self-Organizing Systems;Classical Analysis and ODEs | 7,267longtail
|
2210.14356 | In the first part of this doctoral thesis we develop a regularity theory for
a polyconvex functional in compressible elasticity.
In the second part, we will concentrate on uniqueness questions in various
situations of finite elasticity. Here it is our main objective to establish
uniqueness criteria, which when present, guarantee the uniqueness of the
corresponding global minimizer. Then various applications and generalisations
are discussed one of which is the construction of a counterexample to
regularity.
| [
"math.AP"
] | math.AP | Analysis of PDEs | 205Analysis of PDEs
|
|
2310.20427 | Deep learning in digital pathology brings intelligence and automation as
substantial enhancements to pathological analysis, the gold standard of
clinical diagnosis. However, multiple steps from tissue preparation to slide
imaging introduce various image corruptions, making it difficult for deep
neural network (DNN) models to achieve stable diagnostic results for clinical
use. In order to assess and further enhance the robustness of the models, we
analyze the physical causes of the full-stack corruptions throughout the
pathological life-cycle and propose an Omni-Corruption Emulation (OmniCE)
method to reproduce 21 types of corruptions quantified with 5-level severity.
We then construct three OmniCE-corrupted benchmark datasets at both patch level
and slide level and assess the robustness of popular DNNs in classification and
segmentation tasks. Further, we explore to use the OmniCE-corrupted datasets as
augmentation data for training and experiments to verify that the
generalization ability of the models has been significantly enhanced.
| [
"eess.IV",
"cs.CV",
"cs.LG"
] | eess.IV | cs.CV | Image and Video Processing;Computer Vision and Pattern Recognition;Machine Learning | 3,535Image and Video Processing;Computer Vision and Pattern Recognition;Machine Learning
|
1511.01364 | Further development of the field of all-electric spintronics requires the
successful integration of spin transport channels with spin injector/generator
elements. While with the advent of graphene and related 2D materials high
performance spin channel materials are available, the use of nanostructured
spin generators remains a major challenge. Especially promising for the latter
purpose are 3D topological insulators, whose 2D surface states host massless
Dirac fermions with spin-momentum locking. Here, we demonstrate injection of
spin-polarized current from a topological insulator into graphene, enabled by
its intimate coupling to an ultrathin Bi2Te2Se nanoplatelet within a van der
Waals epitaxial heterostructure. The spin switching signal, whose magnitude
scales inversely with temperature, is detectable up to ~15 K. Our findings
establish topological insulators as prospective future components of spintronic
devices wherein spin manipulation is achieved by purely electrical means.
| [
"cond-mat.mes-hall"
] | cond-mat.mes-hall | Mesoscale and Nanoscale Physics | 4,450Mesoscale and Nanoscale Physics
|
|
1909.06252 | We prove a generalized version of Friedrichs and Gaffney inequalities for a
bounded $(\varepsilon,\delta)$ domain $\Omega\subset\mathbb{R}^n$, $n=2,3$, by
adapting the methods of Jones to our framework.
| [
"math.AP"
] | math.AP | Analysis of PDEs | 205Analysis of PDEs
|
|
1703.07568 | The main purpose of the present paper is to establish a link between
quadrature surfaces (potential theoretic concept) and sandpile dynamics
(Laplacian growth models). For this aim, we introduce a new model of Laplacian
growth on the lattice $\mathbb{Z}^d$ $(d\geq 2)$ which continuously deforms
occupied regions of the \emph{divisible sandpile} model of Levine and Peres, by
redistributing the total mass of the system onto $\frac 1m$-sub-level sets of
the odometer which is a function counting total emissions of mass from lattice
vertices. In free boundary terminology this goes in parallel with singular
perturbation, which is known to converge to a Bernoulli type free boundary.
We prove that models, generated from a single source, have a scaling limit,
if the threshold $m$ is fixed. Moreover, this limit is a ball, and the entire
mass of the system is being redistributed onto an annular ring of thickness
$\frac 1m$. By compactness argument we show that, when $m$ tends to infinity
sufficiently slowly with respect to the scale of the model, then in this case
also there is scaling limit which is a ball, with the mass of the system being
uniformly distributed onto the boundary of that ball, and hence we recover a
quadrature surface in this case.
Depending on the speed of decay of $m$, the visited set of the sandpile
interpolates between spherical and polygonal shapes. Finding a precise
characterisation of this shape-transition phenomenon seems to be a considerable
challenge, which we cannot address at this moment.
| [
"math.AP",
"math.CO",
"math.PR"
] | math.AP | math.CO | Analysis of PDEs;Combinatorics;Probability | 7,267longtail
|
1406.2695 | Originally designed for night-vision equipment, InGaAs detectors are
beginning to achieve background-limited performance in broadband imaging from
the ground. The lower cost of these detectors can enable multi-band
instruments, arrays of small telescopes, and large focal planes that would be
uneconomical with high-performance HgCdTe detectors. We developed a camera to
operate the FLIR AP1121 sensor using deep thermoelectric cooling and
up-the-ramp sampling to minimize noise. We measured a dark current of 163$~e$-
s$^{-1}$ pix$^{-1}$, a read noise of 87$~e$- up-the-ramp, and a well depth of
80k$~e$-. Laboratory photometric testing achieved a stability of 230 ppm
hr$^{-1/2}$, which would be required for detecting exoplanet transits. InGaAs
detectors are also applicable to other branches of near-infrared time-domain
astronomy, ranging from brown dwarf weather to gravitational wave follow-up.
| [
"astro-ph.IM",
"astro-ph.EP"
] | astro-ph.IM | astro-ph.EP | Instrumentation and Methods for Astrophysics;Earth and Planetary Astrophysics | 3,725Instrumentation and Methods for Astrophysics;Earth and Planetary Astrophysics
|
2109.11713 | We develop an optimization framework for the design of acoustic cloaks, with
the aim of overcoming the limitations of usual transformation-based cloaks in
terms of microstructure complexity and shape arbitrarity of the obstacle. This
is achieved by recasting the acoustic cloaking design as a nonlinear optimal
control problem constrained by a linear elliptic partial differential equation.
In this setting, isotropic material properties' distributions realizing the
cloak take the form of control functions and a system of first-order optimality
conditions is derived accordingly. Such isotropic media can then be obtained in
practice with simple hexagonal lattices of inclusions in water.
For this reason, the optimization problem is directly formulated to take into
account suitable partitions of the control domain Two types of inclusions are
considered, and long-wavelength homogenization is used to define the feasible
set of material properties that is employed as a constraint in the optimization
problem. In this manner, we link the stage of material properties optimization
with that of microstructure design, aiming at finding the optimal implementable
solution. As a test benchmark, cloaking of the silhouette of a ship is
considered, for various frequencies and directions of incidence. The resulting
cloak is numerically tested via coupled structural/acoustic simulations.
| [
"math.OC"
] | math.OC | Optimization and Control | 5,234Optimization and Control
|
|
0803.0200 | Angular momentum densities of electromagnetic beams are connected to helicity
(circular polarization) and topological charge (azimuthal phase shift and
vorticity). Computing the electromagnetic fields emitted by a circular antenna
array, analytic expressions are found for the densities of energy, linear and
angular momentum in terms of helicity and vorticity. It is found that the
angular momentum density can be separated into spin and orbital parts, a result
that is known to be true in a beam geometry. The results are of importance for
information-rich radio astronomy and space physics as well as novel radio,
radar, and wireless communication concepts.
| [
"physics.class-ph"
] | physics.class-ph | Classical Physics | 981Classical Physics
|
|
0910.0061 | In the Stueckelberg extension of the Standard Model (StSM), matter in the
hidden sector can act as dark matter. Due to an interplay of mixings produced
by the usual Higgs mechanism and the Stueckelberg mechanism in the neutral
gauge boson sector, the hidden sector matter acquires a milli charge. The
Stueckelberg extension also produces a narrow width Z prime which is detectable
at the Large Hadron Collider. The hidden sector dark matter naturally explains
the PAMELA positron excess by means of a Breit-Wigner enhancement through a Z
prime resonance. We also discuss the origin of milli charge in the context of
the kinetic mixing and the Stueckelberg mixing.
| [
"hep-ph"
] | hep-ph | High Energy Physics - Phenomenology | 3,129High Energy Physics - Phenomenology
|
|
1604.06448 | In this paper we establish a version of homological mirror symmetry for
punctured Riemann surfaces. Following a proposal of Kontsevich we model
A-branes on a punctured surface $\Sigma$ via the topological Fukaya category.
We prove that the topological Fukaya category of $\Sigma$ is equivalent to the
category of matrix factorizations of the mirror LG model $(X,W)$. Along the way
we establish new gluing results for the topological Fukaya category of
punctured surfaces which might be of independent interest.
| [
"math.AT",
"math.AG",
"math.SG"
] | math.AT | math.AG | Algebraic Topology;Algebraic Geometry;Symplectic Geometry | 165Algebraic Topology;Algebraic Geometry;Symplectic Geometry
|
1111.3844 | Different extensions of the classical single-strain SIR model for the host
population, motivated by modeling dengue fever epidemiology, have reported a
rich dynamic structure including deterministic chaos which was able to explain
the large fluctuations of disease incidences. A comparison between the basic
two-strain dengue model, which already captures differences between primary and
secondary infections, with the four-strain dengue model, that introduces the
idea of competition of multiple strains in dengue epidemics shows that the
difference between first and secondary infections drives the rich dynamics more
than the detailed number of strains to be considered in the model structure.
Chaotic dynamics were found to happen at the same parameter region of interest,
for both the two and the four-strain models, able to explain the fluctuations
observed in empirical data and showing a qualitatively good agreement between
empirical data and model simulation. Since the law of parsimony favors the
simplest of two competing models, the two-strain model would be the better
candidate to be analyzed, giving the expected complex behavior to explain the
fluctuations observed in empirical data, and indeed the better option for
estimating all initial conditions as well as the few model parameters based on
the available incidence data.
| [
"nlin.CD",
"math.DS",
"q-bio.PE"
] | nlin.CD | math.DS | Chaotic Dynamics;Dynamical Systems;Populations and Evolution | 7,267longtail
|
1901.03572 | Organometallic compounds constitute a very large group of substances that
contain at least one metal-to-carbon bond in which the carbon is part of an
organic group. They have played a major role in the development of the science
of chemistry. These compounds are used to a large extent as catalysts
(substances that increase the rate of reactions without themselves being
consumed) and as intermediates in the laboratory and in industry. Recently,
novel quantum phenormena such as topological insulators and superconductors
were also suggested in these materials. However, there has been no report on
the experimental exploration for the topological state. Evidence for
superconductivity from the zero-resistivity state in any organometallic
compound has not been achieved yet, though much efforts have been devoted. Here
we report the experimental realization of superconductivity with the critical
temperature of 3.6 K in a potassium-doped organometallic compound, $ i.e.$
tri-$o$-tolylbismuthine with the evidence of both the Meissner effect and the
zero-resistivity state through the $dc$ and $ac$ magnetic susceptibility and
resistivity measurements. The obtained superconducting parameters classify this
compound as a type-II superconductor. The benzene ring is identified to be the
essential superconducting unit in such a phenyl organometallic compound. The
superconducting phase and its composition are determined by the combined
studies of the X-ray diffraction and theoretical calculations as well as the
Raman spectroscopy measurements. These findings enrich the applications of
organometallic compounds in superconductivity and add a new electron-acceptor
family for organic superconductors. This work also points to a large pool for
finding superconductors from organometallic compounds.
| [
"cond-mat.supr-con",
"cond-mat.mtrl-sci"
] | cond-mat.supr-con | cond-mat.mtrl-sci | Superconductivity;Materials Science | 7,079Superconductivity;Materials Science
|
1309.3519 | An international consortium is presently constructing a beamformer for the
Atacama Large Millimeter/submillimeter Array (ALMA) in Chile that will be
available as a facility instrument. The beamformer will aggregate the entire
collecting area of the array into a single, very large aperture. The
extraordinary sensitivity of phased ALMA, combined with the extremely fine
angular resolution available on baselines to the Northern Hemisphere, will
enable transformational new very long baseline interferometry (VLBI)
observations in Bands 6 and 7 (1.3 and 0.8 mm) and provide substantial
improvements to existing VLBI arrays in Bands 1 and 3 (7 and 3 mm). The ALMA
beamformer will have impact on a variety of scientific topics, including
accretion and outflow processes around black holes in active galactic nuclei
(AGN), tests of general relativity near black holes, jet launch and collimation
from AGN and microquasars, pulsar and magnetar emission processes, the chemical
history of the universe and the evolution of fundamental constants across
cosmic time, maser science, and astrometry.
| [
"astro-ph.IM",
"astro-ph.CO",
"astro-ph.GA",
"astro-ph.SR"
] | astro-ph.IM | astro-ph.CO | Instrumentation and Methods for Astrophysics;Cosmology and Nongalactic Astrophysics;Astrophysics of Galaxies;Solar and Stellar Astrophysics | 3,710Instrumentation and Methods for Astrophysics;Cosmology and Nongalactic Astrophysics;Astrophysics of Galaxies;Solar and Stellar Astrophysics
|
1205.6855 | The real-time nature of Twitter means that term distributions in tweets and
in search queries change rapidly: the most frequent terms in one hour may look
very different from those in the next. Informally, we call this phenomenon
"churn". Our interest in analyzing churn stems from the perspective of
real-time search. Nearly all ranking functions, machine-learned or otherwise,
depend on term statistics such as term frequency, document frequency, as well
as query frequencies. In the real-time context, how do we compute these
statistics, considering that the underlying distributions change rapidly? In
this paper, we present an analysis of tweet and query churn on Twitter, as a
first step to answering this question. Analyses reveal interesting insights on
the temporal dynamics of term distributions on Twitter and hold implications
for the design of search systems.
| [
"cs.IR",
"cs.SI"
] | cs.IR | cs.SI | Information Retrieval;Social and Information Networks | 3,620Information Retrieval;Social and Information Networks
|
2210.05952 | Generative models such as generative adversarial networks and autoencoders
have gained a great deal of attention in the medical field due to their
excellent data generation capability. This paper provides a comprehensive
survey of generative models for three-dimensional (3D) volumes, focusing on the
brain and heart. A new and elaborate taxonomy of unconditional and conditional
generative models is proposed to cover diverse medical tasks for the brain and
heart: unconditional synthesis, classification, conditional synthesis,
segmentation, denoising, detection, and registration. We provide relevant
background, examine each task and also suggest potential future directions. A
list of the latest publications will be updated on Github to keep up with the
rapid influx of papers at
https://github.com/csyanbin/3D-Medical-Generative-Survey.
| [
"eess.IV",
"cs.CV"
] | eess.IV | cs.CV | Image and Video Processing;Computer Vision and Pattern Recognition | 3,532Image and Video Processing;Computer Vision and Pattern Recognition
|
0810.2380 | We investigate the electronic states of the CoO_2 plane in the layered cobalt
oxides Na_{0.5}CoO_{2} using the realistic 11 band d-p model on a
two-dimensional triangular lattice. Effects of the Coulomb interaction on a Co
site: the intra- and inter-orbital direct terms U and U', the exchange coupling
J and the pair-transfer J', are treated within the Hartree-Fock approximation.
It is found that the metallic antiferromagnetism takes place below T_{c1} and,
in addition, the orbital order accompanied by the small charge order takes
place below T_{c2} (< T_{c1}) where the system becomes insulator. The obtained
results are consistent with the successive phase transitions observed in
Na_{0.5}CoO_{2}.
| [
"cond-mat.str-el"
] | cond-mat.str-el | Strongly Correlated Electrons | 6,979Strongly Correlated Electrons
|
|
astro-ph/0410416 | We report the discovery of SDSSJ1049+5103, an overdensity of resolved blue
stars at (\alpha_{2000}, \delta_{2000}) = (162.343, 51.051). This object
appears to be an old, metal-poor stellar system at a distance of 45 +/- 10 kpc,
with a half-light radius of 23$\pm 10$ pc and an absolute magnitude of M_V =
-3.0^{+2.0}_{-0.7}. One star that is likely associated with this companion has
an SDSS spectrum confirming it as a blue horizontal branch star at 48 kpc. The
color-magnitude diagram of SDSSJ1049+5103 contains few, if any, horizontal or
red giant branch stars, similar to the anomalously faint globular cluster AM 4.
The size and luminosity of SDSSJ1049+5103 places it at the intersection of the
size-luminosity relationships followed by known globular clusters and by Milky
Way dwarf spheroidals. If SDSSJ1049+5103 is a globular cluster, then its
properties are consistent with the established trend that the largest radius
Galactic globular clusters are all in the outer halo. However, the five known
globular clusters with similarly faint absolute magnitudes all have half-mass
radii that are smaller than SDSSJ1049+5103 by a factor of $\gtrsim$ 5. If it is
a dwarf spheroidal, then it is the faintest yet known by two orders of
magnitude, and is the first example of the ultra-faint dwarfs predicted by some
theories. The uncertain nature of this new system underscores the sometimes
ambiguous distinction between globular clusters and dwarf spheroidals. A simple
friends-of-friends search for similar blue, small scalesize star clusters
detected all known globulars and dwarfs closer than 50 kpc in the SDSS area,
but yielded no other candidates as robust as SDSSJ1049+5103.
| [
"astro-ph"
] | astro-ph | Astrophysics | 463Astrophysics
|
|
1303.1233 | We present a self contained formalism modelled after the Brownian motion of a
quantum harmonic oscillator for describing the performance of microscopic
Brownian heat engines like Carnot, Stirling and Otto engines. Our theory,
besides reproducing the standard thermodynamics results in the steady state
enables permits us to study the role dissipation plays in determining the
efficiency of Brownian heat engines under actual laboratory conditions. In
particular, we analyse in detail the dynamics associated with decoupling a
system in equilibrium with one bath and recoupling it to another bath and
obtain exact analytical results which are shown to have significant
ramifications on the efficiencies of engines involving such a step. We also
develop a simple yet powerful technique for computing corrections to the steady
state results arising from finite operation time and use it to arrive at the
thermodynamic complementarity relations for various operating conditions and
also to compute the efficiencies of the three engines cited above at maximum
power. Some of the methods and techniques and exactly solvable models presented
here are interesting in their own right and, in our opinion, would find useful
applications in other contexts as well.
| [
"quant-ph"
] | quant-ph | Quantum Physics | 5,985Quantum Physics
|
|
2008.00717 | We studied the symmetry of magnetic properties and the resulting magnetic
textures in ultra-thin epitaxial Au$_{0.67}$Pt$_{0.33}$/Co/W, a model system
exhibiting perpendicular magnetic anisotropy and interface
Dzyaloshinskii-Moriya interaction (DMI). As a peculiar feature, the
C$_\mathrm{2v}$ crystal symmetry induced by the Co/W interface results in an
additional uniaxial in-plane magnetic anisotropy in the cobalt layer.
Photoemission electron microscopy with magnetic sensitivity reveals the
formation of self-organized magnetic stripe domains oriented parallel to the
hard in-plane magnetization axis. We attribute this behavior to the lower
domain wall energy when oriented along this axis, where both the DMI and the
in-plane magnetic anisotropy favor a N\'{e}el domain wall configuration. The
anisotropic domain wall energy also leads to the formation of elliptical
skyrmion bubbles in a weak out-of-plane magnetic field.
| [
"cond-mat.mtrl-sci",
"cond-mat.mes-hall"
] | cond-mat.mtrl-sci | cond-mat.mes-hall | Materials Science;Mesoscale and Nanoscale Physics | 4,330Materials Science;Mesoscale and Nanoscale Physics
|