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1102.2839 | In this work we investigate the dynamical properties of a mixture of mutually
interacting spherical molecules of different masses and sizes. From an analysis
of the microscopic laws governing the motion of the molecules we derive a set
of non-local self-consistent equations for the singlet phase-space distribution
functions. The theory is shown to reproduce the hydrodynamic equations for the
densities of each species, the total momentum and the local temperature. The
non ideal gas interaction term is separated into a contribution due to the
repulsive part, which is treated by means of the revised Enskog theory for hard
spheres, and an attractive contribution treated within the random phase
approximation. The present formulation accounts for the effects of the density
and velocity inhomogeneities both on the thermodynamic and transport properties
of the fluid. In a special limit, where one species is massive and diluted, the
theory leads to a description which is formally identical to the dynamic
density functional equation governing the time evolution of a colloidal system.
The derivation also determines the dependence of the friction coefficient,
appearing in the dynamic density functional theory, on the microscopic
parameters of the solvent. However, the predicted value takes into account only
the collisional contributions to the friction and not the Stokes friction of
hydrodynamic origin, suggesting that velocity correlations should be
incorporated in a more complete treatment.
| [
"cond-mat.soft",
"cond-mat.mes-hall"
] | cond-mat.soft | cond-mat.mes-hall | Soft Condensed Matter;Mesoscale and Nanoscale Physics | 6,593Soft Condensed Matter;Mesoscale and Nanoscale Physics
|
1001.4675 | A method for tuning parameters in Monte Carlo generators is described and
applied to a specific case. The method works in the following way: each
observable is generated several times using different values of the parameters
to be tuned. The output is then approximated by some analytic form to describe
the dependence of the observables on the parameters. This approximation is used
to find the values of the parameter that give the best description of the
experimental data. This results in significantly faster fitting compared to an
approach in which the generator is called iteratively. As an application, we
employ this method to fit the parameters of the unintegrated gluon density used
in the CASCADE Monte Carlo generator, using inclusive deep inelastic data
measured by the H1 Collaboration. We discuss the results of the fit, its
limitations, and its strong points.
| [
"hep-ph"
] | hep-ph | High Energy Physics - Phenomenology | 3,129High Energy Physics - Phenomenology
|
|
cs/0612085 | Since its inception as a student project in 2001, initially just for the
handling (as the name implies) of convex polyhedra, the Parma Polyhedra Library
has been continuously improved and extended by joining scrupulous research on
the theoretical foundations of (possibly non-convex) numerical abstractions to
a total adherence to the best available practices in software development. Even
though it is still not fully mature and functionally complete, the Parma
Polyhedra Library already offers a combination of functionality, reliability,
usability and performance that is not matched by similar, freely available
libraries. In this paper, we present the main features of the current version
of the library, emphasizing those that distinguish it from other similar
libraries and those that are important for applications in the field of
analysis and verification of hardware and software systems.
| [
"cs.MS",
"cs.PL"
] | cs.MS | cs.PL | Mathematical Software;Programming Languages | 4,411Mathematical Software;Programming Languages
|
quant-ph/0208011 | The black-body radiation is reinterpreted in terms of the photon's many-body
wave functions in analogy with the condensed matter physics. This
interpretation has implications on the wave-particle duality, and on the
difference between the photon and the matter wave.
| [
"quant-ph"
] | quant-ph | Quantum Physics | 5,985Quantum Physics
|
|
1907.07795 | The family of left-to-right GCD algorithms reduces input numbers by
repeatedly subtracting the smaller number, or multiple of the smaller number,
from the larger number. This paper describes how to extend any such algorithm
to compute the Jacobi symbol, using a single table lookup per reduction. For
both quadratic time GCD algorithms (Euclid, Lehmer) and subquadratic algorithms
(Knuth, Sch\"onhage, M\"oller), the additional cost is linear, roughly one
table lookup per quotient in the quotient sequence. This method was used for
the 2010 rewrite of the Jacobi symbol computation in GMP.
| [
"cs.DS",
"cs.DM"
] | cs.DS | cs.DM | Data Structures and Algorithms;Discrete Mathematics | 1,938Data Structures and Algorithms;Discrete Mathematics
|
1101.4882 | With single crystal X-ray diffraction studies, we compare the structures of
three sample showing optimal superconductivity, K0.774(4)Fe1.613(2)Se2,
K0.738(6)Fe1.631(3)Se2 and Cs0.748(2)Fe1.626(1)Se2. All have an almost
identical ordered vacancy structure with a ({\sqrt}5 x {\sqrt}5 x 1) super
cell. The tetragonal unit cell, space group I4/m, possesses lattice parameters
at 250K of a = b = 8.729(2) {\AA} and c = 14.120(3) {\AA}, a = b = 8.7186(12)
{\AA} and c = 14.0853(19) {\AA} and at 295 K, a = b = 8.8617(16) {\AA} and c =
15.304(3) {\AA} for the three crystals, respectively. The structure contains
two iron sites; one is almost completely empty, whilst the other is fully
occupied. There are similarly two alkali metal sites that are occupied in the
range of 72.2(2) % to 85.3(3) %. The inclusion of alkali metals and the
presence of vacancies within the structure allows for considerable relaxation
of the FeSe4 tetrahedron, compared with members of the Fe(Te, Se, S) series,
and the resulting shift of the Se - F - Se bond angles to less distorted
geometry could be important in understanding the associated increase in the
superconducting transition temperature. The structure of these superconductors
distinguishes themselves from the structure of the non-superconducting phases
by an almost complete absence of Fe on the (0 0.5 0.25) site as well as lower
alkali metal occupancy that ensures an exact Fe2+ oxidation state, which are
clearly critical parameters in the promotion of superconductivity.
| [
"cond-mat.supr-con",
"cond-mat.mtrl-sci",
"cond-mat.str-el"
] | cond-mat.supr-con | cond-mat.mtrl-sci | Superconductivity;Materials Science;Strongly Correlated Electrons | 7,082Superconductivity;Materials Science;Strongly Correlated Electrons
|
2307.16036 | Researchers in the field of ultra-intense laser science are beginning to
embrace machine learning methods. In this study we consider three different
machine learning methods -- a two-hidden layer neural network, Support Vector
Regression and Gaussian Process Regression -- and compare how well they can
learn from a synthetic data set for proton acceleration in the Target Normal
Sheath Acceleration regime. The synthetic data set was generated from a
previously published theoretical model by Fuchs et al. 2005 that we modified.
Once trained, these machine learning methods can assist with efforts to
maximize the peak proton energy, or with the more general problem of
configuring the laser system to produce a proton energy spectrum with desired
characteristics. In our study we focus on both the accuracy of the machine
learning methods and the performance on one GPU including the memory
consumption. Although it is arguably the least sophisticated machine learning
model we considered, Support Vector Regression performed very well in our
tests.
| [
"physics.plasm-ph",
"physics.comp-ph",
"physics.data-an"
] | physics.plasm-ph | physics.comp-ph | Plasma Physics;Computational Physics;Data Analysis, Statistics and Probability | 7,267longtail
|
1504.03239 | Global Value Numbering (GVN) is an important static analysis to detect
equivalent expressions in a program. We present an iterative data-flow analysis
GVN algorithm in SSA for the purpose of detecting total redundancies. The
central challenge is defining a join operation to detect equivalences at a join
point in polynomial time such that later occurrences of redundant expressions
could be detected. For this purpose, we introduce the novel concept of value
$\phi$-function. We claim the algorithm is precise and takes only polynomial
time.
| [
"cs.PL"
] | cs.PL | Programming Languages | 5,796Programming Languages
|
|
2209.09474 | The blast-wave (BW) spectrum model has been applied extensively to
nucleus-nucleus collision data with the intention to demonstrate formation of a
quark-gluon plasma (QGP) in more-central A-A collisions. More recently the BW
model has been applied to p-p, d-Au and p-Pb collisions. Such results are
interpreted to indicate that ``collectivity'' (flows) and QGP appear in smaller
systems. I consider variations of the BW model and supporting assumptions. In
this talk I review BW analysis of identified-hadron spectra from 5 TeV p-Pb
collisions and examine the shape evolution of model spectra with collision
centrality. I evaluate data-model fit quality using conventional statistical
measures. I conclude that the BW model is not a valid data model.
| [
"hep-ph"
] | hep-ph | High Energy Physics - Phenomenology | 3,129High Energy Physics - Phenomenology
|
|
hep-ph/9607281 | We argue that large non-decoupling effects of heavy neutrinos can appear
naturally in manifestly left-right symmetric models due to the minimization
conditions of the scalar potential and the structure of vev's imposed by
phenomenology. We derive constraints on off-diagonal light-heavy and
heavy-heavy neutrino mixings from the searches for lepton violating decays
$\mu\rightarrow e\gamma,$ $\mu\rightarrow e e^-e^+$ and $\mu-e$ conversion in
nuclei. The most stringent limits come from the latter process because its
amplitude shows a quadratic non-decoupling dependence on the heavy neutrino
mass. Due to the suppression of right-handed currents by large $W_R$ mass the
present experiments are not sensitive to the intergenerational mixings between
heavy neutrinos if $M_{W_R}>200$ TeV.
| [
"hep-ph"
] | hep-ph | High Energy Physics - Phenomenology | 3,129High Energy Physics - Phenomenology
|
|
2112.11403 | This paper describes a calculation of the spontaneous emission limited
linewidth of a semiconductor laser consisting of hybrid or heterogeneously
integrated, silicon and III-V intracavity components. Central to the approach
are a) description of the multi-element laser cavity in terms of composite
laser/free-space eigenmodes, b) use of multimode laser theory to treat mode
competition and multiwave mixing, and c) incorporation of quantum-optical
contributions to account for spontaneous emission effects. Application of the
model is illustrated for the case of linewidth narrowing in an InAs quantum-dot
laser coupled to a high-Q SiN cavity.
| [
"physics.optics"
] | physics.optics | Optics | 5,146Optics
|
|
1909.12859 | Accurate simulations of the 21-cm signal from the Epoch of Reionization
require the generation of maps at specific frequencies given the values of
astrophysical and cosmological parameters. The peculiar velocities of the
hydrogen atoms producing the 21-cm radiation result in a shift in the observed
frequency of the 21-cm radiation and changes the amplitude of the signal
itself. This is not an effect we can remove but instead needs to be accurately
modelled to ensure we infer the correct physical parameters from an
observation. We describe the full calculation of the distortion of the 21-cm
signal, and propose a new code that integrates the 21-cm intensity along the
line of sight for each individual light cone pixel to fully capture the
intensity contributions from multiple redshifts. This algorithm naturally deals
with the typical divergences found in standard approaches, allowing for large
optical depths and 21-cm absorption events at high redshifts. We find the new
method results in up to a 60% decrease in power on the largest scales on the
sky, and an increase of over 80% on the smallest scales on the sky. We find
that the new implementation of the light cone results in a longer tail of
bright temperatures in the brightness temperature distribution, as a result of
the successful circumventing of a previous cap that had to be implemented to
avoid a divergence in the brightness temperature. We conclude that this full
treatment of the evolution of the light cone pixel can be an important effect.
| [
"astro-ph.CO"
] | astro-ph.CO | Cosmology and Nongalactic Astrophysics | 1,725Cosmology and Nongalactic Astrophysics
|
|
2102.04948 | This paper studies a system of multi-dimensional reflected backward
stochastic differential equations with oblique reflections (RBSDEs for short)
in infinite horizon associated to switching problems. The existence and
uniqueness of the adapted solution is obtained by using a method based oa
combination of penalization, verification method and contraction property.
| [
"math.PR"
] | math.PR | Probability | 5,709Probability
|
|
1003.5034 | We suggest a possible explanation for the high frequency quasi-periodic
oscillations (QPOs) in black hole low mass X-ray binaries. By solving the
perturbation general relativistic magnetohydrodynamic equations, we find two
stable modes of the Alf\'ven wave in the the accretion disks with toroidal
magnetic fields. We suggest that these two modes may lead to the double high
frequency QPOs if they are produced in the transition region between the inner
advection dominated accretion flow and the outer thin disk. This model
naturally accounts for the 3 : 2 relation for the upper and lower frequencies
of the QPOs, and the relation between the black hole mass and QPO frequency.
| [
"astro-ph.HE"
] | astro-ph.HE | High Energy Astrophysical Phenomena | 2,990High Energy Astrophysical Phenomena
|
|
0805.1199 | A relation is found between pulsed measurements of the excited state
probability of a two-level atom illuminated by a driving laser, and a
continuous measurement by a second laser coupling the excited state to a third
state which decays rapidly and irreversibly. We find the time between pulses to
achieve the same average detection time than a given continuous measurement in
strong, weak, or intermediate coupling regimes, generalizing the results in L.
S. Schulman, Phys. Rev. A 57, 1509 (1998).
| [
"quant-ph"
] | quant-ph | Quantum Physics | 5,985Quantum Physics
|
|
1203.1752 | The lattice dynamics of the $\rm YMnO_3$ magneto-electric compound has been
investigated using density functional calculations, both in the ferroelectric
and the paraelectric phases. The coherence between the computed and
experimental data is very good in the low temperature phase. Using group
theory, modes continuity and our calculations we were able to show that the
phonons modes observed by Raman scattering at 1200K are only compatible with
the ferroelectric $P6_{3} cm$ space group, thus supporting the idea of a
ferroelectric to paraelectric phase transition at higher temperature. Finally
we proposed a candidate for the phonon part of the observed electro-magnon.
This mode, inactive both in Raman scattering and in Infra-Red, was shown to
strongly couple to the Mn-Mn magnetic interactions.
| [
"cond-mat.mtrl-sci",
"cond-mat.str-el"
] | cond-mat.mtrl-sci | cond-mat.str-el | Materials Science;Strongly Correlated Electrons | 4,377Materials Science;Strongly Correlated Electrons
|
2312.04346 | Measurement uncertainties, represented by cyber-attacks and data losses,
seriously degrade the quality of power system measurements. Fortunately, the
powerful generation ability of the denoising diffusion models can enable more
precise measurement generation for power system data recovery. However, the
controllable data generation and efficient computing methods of denoising
diffusion models for deterministic trajectory still need further investigation.
To this end, this paper proposes an improved two-stage denoising diffusion
model (TSDM) to identify and reconstruct the measurements with various
measurement uncertainties. The first stage of the model comprises a
classifier-guided conditional anomaly detection component, while the second
stage involves diffusion-based measurement imputation component. Moreover, the
proposed TSDM adopts precise means and optimal variances to accelerate the
diffusion generation process with subsequence sampling. Extensive numerical
case studies demonstrate that the proposed TSDM can accurately recover power
system measurements despite strong randomness under renewable energy
integration and highly nonlinear dynamics under complex cyber-physical
contingencies. Additionally, the proposed TSDM has stronger robustness compared
to existing reconstruction networks and exhibits lower computational complexity
than general denoising diffusion models.
| [
"cs.LG",
"cs.CR"
] | cs.LG | cs.CR | Machine Learning;Cryptography and Security | 4,077Machine Learning;Cryptography and Security
|
2308.14711 | We break the linear link between the layer size and its inference cost by
introducing the fast feedforward (FFF) architecture, a log-time alternative to
feedforward networks. We demonstrate that FFFs are up to 220x faster than
feedforward networks, up to 6x faster than mixture-of-experts networks, and
exhibit better training properties than mixtures of experts thanks to noiseless
conditional execution. Pushing FFFs to the limit, we show that they can use as
little as 1% of layer neurons for inference in vision transformers while
preserving 94.2% of predictive performance.
| [
"cs.LG",
"cs.AI",
"cs.PF"
] | cs.LG | cs.AI | Machine Learning;Artificial Intelligence;Performance | 3,974Machine Learning;Artificial Intelligence;Performance
|
0708.2597 | The impact dynamics between wet surfaces, which dominates the mechanical
properties of wet granular matter, is studied both experimentally and
theoretically. It is shown that the hysteretic formation and rupture of liquid
capillary bridges between adjacent grains accounts reasonably well for most
relevant cases of wet granular matter. The various dissipation mechanisms are
discussed with particular emphasis on their relevance. Variations of the
rupture energy loss with the impact energy are quantified and discussed.
| [
"cond-mat.soft"
] | cond-mat.soft | Soft Condensed Matter | 6,537Soft Condensed Matter
|
|
1112.5064 | Future quantum information networks will likely consist of quantum and
classical agents, who have the ability to communicate in a variety of ways with
trusted and untrusted parties and securely delegate computational tasks to
untrusted large-scale quantum computing servers. Multipartite quantum
entanglement is a fundamental resource for such a network and hence it is
imperative to study the possibility of verifying a multipartite entanglement
source in a way that is efficient and provides strong guarantees even in the
presence of multiple dishonest parties. In this work, we show how an agent of a
quantum network can perform a distributed verification of a multipartite
entangled source with minimal resources, which is, nevertheless, resistant
against any number of dishonest parties. Moreover, we provide a tight tradeoff
between the level of security and the distance between the state produced by
the source and the ideal maximally entangled state. Last, by adding the
resource of a trusted common random source, we can further provide security
guarantees for all honest parties in the quantum network simultaneously.
| [
"quant-ph"
] | quant-ph | Quantum Physics | 5,985Quantum Physics
|
|
1909.09566 | Objective monitoring and assessment of human motor behavior can improve the
diagnosis and management of several medical conditions. Over the past decade,
significant advances have been made in the use of wearable technology for
continuously monitoring human motor behavior in free-living conditions.
However, wearable technology remains ill-suited for applications which require
monitoring and interpretation of complex motor behaviors (e.g. involving
interactions with the environment). Recent advances in computer vision and deep
learning have opened up new possibilities for extracting information from video
recordings. In this paper, we present a hierarchical vision-based behavior
phenotyping method for classification of basic human actions in video
recordings performed using a single RGB camera. Our method addresses challenges
associated with tracking multiple human actors and classification of actions in
videos recorded in changing environments with different fields of view. We
implement a cascaded pose tracker that uses temporal relationships between
detections for short-term tracking and appearance-based tracklet fusion for
long-term tracking. Furthermore, for action classification, we use pose
evolution maps derived from the cascaded pose tracker as low-dimensional and
interpretable representations of the movement sequences for training a
convolutional neural network. The cascaded pose tracker achieves an average
accuracy of 88\% in tracking the target human actor in our video recordings,
and overall system achieves average test accuracy of 84\% for target-specific
action classification in untrimmed video recordings.
| [
"cs.CV"
] | cs.CV | Computer Vision and Pattern Recognition | 1,498Computer Vision and Pattern Recognition
|
|
2003.12353 | This article surveys engineering and neuroscientific models of planning as a
cognitive function, which is regarded as a typical function of fluid
intelligence in the discussion of general intelligence. It aims to present
existing planning models as references for realizing the planning function in
brain-inspired AI or artificial general intelligence (AGI). It also proposes
themes for the research and development of brain-inspired AI from the viewpoint
of tasks and architecture.
| [
"cs.AI",
"q-bio.NC"
] | cs.AI | q-bio.NC | Artificial Intelligence;Neurons and Cognition | 446Artificial Intelligence;Neurons and Cognition
|
math/9602221 | This paper gives an expository account of our experiments concerning
relations between modular forms for congruence subgroups of SL(3,Z) and three
dimensional Galois representations. The main new result presented here is a
calculation of the variations of the Hodge structure corresponding to the
motives we consider in realizing the Galois representations. It turns out that
the period spaces for the Hodge structures are four dimensional, while the
geometric realizations of such Hodge structures can appear in subspaces of
dimension at most one.
| [
"math.NT"
] | math.NT | Number Theory | 4,945Number Theory
|
|
2211.13927 | Dielectric mirrors comprising thin-film multilayers are widely used in
optical experiments because they can achieve substantially higher reflectance
compared to metal mirrors. Here we investigate potential problems that can
arise when dielectric mirrors are used at oblique incidence, in particular for
focused beams. We found that light beams reflected from dielectric mirrors can
experience lateral beam shifts, beam-shape distortion, and depolarization, and
these effects have a strong dependence on wavelength, incident angle, and
incident polarization. Because vendors of dielectric mirrors typically do not
share the particular layer structure of their products, we designed and
simulated several dielectric-mirror stacks, and then also measured the lateral
beam shift from two commercial dielectric mirrors and one coated metal mirror.
We hope that this paper brings awareness of the tradeoffs between dielectric
mirrors and front-surface metal mirrors in certain optics experiments, and
suggest that vendors of dielectric mirrors provide information about beam
shifts, distortion, and depolarization when their products are used at oblique
incidence.
| [
"physics.optics",
"physics.app-ph"
] | physics.optics | physics.app-ph | Optics;Applied Physics | 5,150Optics;Applied Physics
|
1805.00010 | We present nebular-phase spectra of the Type Ia supernova (SN Ia) 2016brx, a
member of the 1991bg-like subclass that lies at the faint end of the SN Ia
luminosity function. Nebular spectra are available for only three other
1991bg-like SNe, and their Co line centers are all within <~ 500 km/s of each
other. In contrast, the nebular Co line center of SN 2016brx is blue-shifted by
>1500 km/s compared to them and by ~1200 km/s compared to the rest frame. This
is a significant shift relative to the narrow nebular line velocity dispersion
of <~ 2000 km/s of these SNe. The large range of nebular line shifts implies
that the Ni56 in the ejecta of SN 1991bg-like events is off-center by ~1000
km/s rather than universally centrally confined as previously suggested. With
the addition of SN 2016brx, the Co nebular line shapes of 1991bg-like objects
appear to connect with the brighter SNe Ia that show double-peak profiles,
hinting at a continuous distribution of line profiles among SNe Ia. One class
of models to produce both off-center and bi-modal Ni56 distributions is
collisions of white dwarfs with unequal and equal masses.
| [
"astro-ph.HE",
"astro-ph.SR"
] | astro-ph.HE | astro-ph.SR | High Energy Astrophysical Phenomena;Solar and Stellar Astrophysics | 3,047High Energy Astrophysical Phenomena;Solar and Stellar Astrophysics
|
1210.1342 | Following a symmetrization procedure proposed recently by Nowak and Stempak,
we consider the setting of symmetrized Jacobi expansions. In this framework we
investigate mapping properties of several fundamental harmonic analysis
operators, including Riesz transforms, Poisson semigroup maximal operator,
Littlewood-Paley-Stein square functions and multipliers of Laplace and
Laplace-Stieltjes transform type. Our paper delivers also some new results in
the original setting of classical Jacobi expansions.
| [
"math.CA"
] | math.CA | Classical Analysis and ODEs | 934Classical Analysis and ODEs
|
|
hep-ph/9508402 | Fermion masses and mixing angles including that of neutrinos are studied in a
model with symmetry group SUSY $SO(10)\times \Delta (48) \times U(1)$.
Universality of Yukawa coupling of superfields is assumed. The resulting
texture of mass matrices in the low energy region depends only on a single
coupling constant and VEVs caused by necessary symmetry breaking. 13 parameters
involving masses and mixing angles in the quark and charged lepton sector are
successfully described by only five parameters with two of them determined by
the scales of U(1), SO(10) and SU(5) symmetry breaking compatible with the
requirement of grand unification and proton decay. The neutrino masses and
mixing angles in the leptonic sector are also determined with the addition of a
Majorana coupling term. It is found that LSND $\bar{\nu}_{\mu}\rightarrow
\bar{\nu}_{e}$ events, atmospheric neutrino deficit and the mass limit put by
hot dark matter can be naturally explained. Solar neutrino puzzle can be solved
only by introducing sterile neutrino with one additional parameter. More
precise measurements of $\alpha_{s}(M_{Z})$, $V_{cb}$, $V_{ub}/V_{cb}$,
$m_{b}$, $m_{t}$, as well as various CP violation and neutrino oscillation
experiments will provide crucial tests of the present model.
| [
"hep-ph"
] | hep-ph | High Energy Physics - Phenomenology | 3,129High Energy Physics - Phenomenology
|
|
1603.05977 | The H.E.S.S. collaboration has reported a high-energy spherically symmetric
diffuse gamma-ray emission in the inner 50 pc of the Milky Way, up to ~ 50 TeV.
Here we propose a leptonic model which provides an alternative to the hadronic
scenario presented by the H.E.S.S. collaboration, and connects the newly
reported TeV emission to the Fermi-LAT Galactic center GeV excess. Our model
relies on a combination of inverse Compton emission from a population of
millisecond pulsars---which can account for the GeV excess---and a supermassive
black hole-induced spike of heavy (~ 60 TeV) dark matter particles annihilating
into electrons with a sub-thermal cross-section. With an up-to-date
interstellar radiation field, as well as a standard magnetic field and
diffusion set-up, our model accounts for the spectral morphology of the
detected emission. Moreover, we show that the dark matter induced emission
reproduces the spatial morphology of the H.E.S.S. signal above ~ 10 TeV, while
we obtain a slightly more extended component from pulsars at lower energies,
which could be used as a prediction for future H.E.S.S. observations.
| [
"astro-ph.HE",
"astro-ph.CO",
"astro-ph.GA",
"hep-ph"
] | astro-ph.HE | astro-ph.CO | High Energy Astrophysical Phenomena;Cosmology and Nongalactic Astrophysics;Astrophysics of Galaxies;High Energy Physics - Phenomenology | 3,006High Energy Astrophysical Phenomena;Cosmology and Nongalactic Astrophysics;Astrophysics of Galaxies;High Energy Physics - Phenomenology
|
1506.01521 | We analyze the resonant variation of the optical reflection on an infiltrated
artificial opal made of transparent nanospheres. The resonant infiltration is
considered as a perturbation in the frame of a previously described
one-dimensional model based upon a stratified effective index. We show that for
a thin slice of resonant medium, the resonant response oscillates with the
position of this slice. We derive that for adequate conditions of incidence
angle, this spatially oscillating behavior matches the geometrical periodicity
of the opal, and hence the related density of resonant infiltration. Close to
these matching conditions, the resonant response of the global infiltration
varies sharply in amplitude and shape with the incidence angle and
polarization. The corresponding resonant reflection originates from a rather
deep infiltration, up to several wavelengths or layers of spheres. Finally, we
discuss the relationship between the present predictions and our previous
observations on an opal infiltrated with a resonant vapor.
| [
"physics.optics"
] | physics.optics | Optics | 5,146Optics
|
|
1402.5958 | For two electrically small nonreciprocal scatterers an analytical
electromagnetic model of polarizabilities is developed. Both particles are
bianisotropic: the so-called Tellegen-omega particle and moving-chiral
particle. Analytical results are compared to the full-wave numerical
simulations. Both models satisfy to main physical restrictions and leave no
doubts in the possibility to realize these particles experimentally. This paper
is a necessary step towards applications of nonreciprocal bianisotropic
particles such as perfect electromagnetic isolators, twist polarizers,
thin-sheet phase shifters, and other devices.
| [
"physics.optics"
] | physics.optics | Optics | 5,146Optics
|
|
1408.6844 | We present evidence for the presence of a low-amplitude kinematically
distinct component in the giant early-type galaxy M87, via datasets obtained
with the SAURON and MUSE integral-field spectroscopic units. The MUSE velocity
field reveals a strong twist of ~140 deg within the central 30 arcsec
connecting outwards such a kinematically distinct core to a prolate-like
rotation around the large-scale photometric major-axis of the galaxy. The
existence of these kinematic features within the apparently round central
regions of M87 implies a non-axisymmetric and complex shape for this galaxy,
which could be further constrained using the presented kinematics. The
associated orbital structure should be interpreted together with other tracers
of the gravitational potential probed at larger scales (e.g., Globular
Clusters, Ultra Compact Dwarfs, Planetary Nebulae): it would offer an insight
in the assembly history of one of the brightest galaxies in the Virgo Cluster.
These data also demonstrate the potential of the MUSE spectrograph to uncover
low-amplitude spectral signatures.
| [
"astro-ph.GA"
] | astro-ph.GA | Astrophysics of Galaxies | 464Astrophysics of Galaxies
|
|
1505.00959 | We discuss the boundary effect of anomaly-induced action in two-dimensional
spacetime, which is ignored in previous studies. Anomaly-induced action, which
gives the stress tensor with the same trace as the trace anomaly, can be
represented in terms of local operators by introducing an auxiliary scalar
field. Although the degrees of freedom of the auxiliary field can in principle
describe the quantum states of the original field, the principal relation
between them was unclear. We show here that, by considering the boundary
effect, the solutions of classical auxiliary fields are naturally related to
the quantum states of the original field. We demonstrate this conclusion via
several examples such as the flat, black hole and the de Sitter spacetime.
| [
"gr-qc",
"hep-th"
] | gr-qc | hep-th | General Relativity and Quantum Cosmology;High Energy Physics - Theory | 2,746General Relativity and Quantum Cosmology;High Energy Physics - Theory
|
1503.02672 | The Forward-Backward Asymmetry (AFB) in Z' physics is commonly only perceived
as the observable which possibly allows one to interpret a Z' signal by
distinguishing different models of such (heavy) spin-1 bosons. In this paper,
we examine the potential of AFB in setting bounds on or even discovering a Z'
boson at the Large Hadron Collider (LHC) and show that it might be a powerful
tool for this purpose. We analyse two different scenarios: Z' bosons with a
narrow and wide width, respectively. We find that, in the first case, the
significance of the AFB search can be comparable with that of the bump search
usually adopted by the experimental collaborations; however, being a ratio of
(differential) cross sections the AFB has the advantage of reducing
systematical errors. In the second case, the AFB search can win over the bump
search in terms of event shape, as the structure of the AFB distribution as a
function of the invariant mass of the reconstructed Z'boson could nail down the
new broad resonance much better than the event counting strategy usually
adopted in such cases.
| [
"hep-ph"
] | hep-ph | High Energy Physics - Phenomenology | 3,129High Energy Physics - Phenomenology
|
|
2201.13099 | We study the problem of computing the vitality of edges and vertices with
respect to the $st$-max flow in undirected planar graphs, where the vitality of
an edge/vertex is the $st$-max flow decrease when the edge/vertex is removed
from the graph. This allows us to establish the vulnerability of the graph with
respect to the $st$-max flow.
We give efficient algorithms to compute an additive guaranteed approximation
of the vitality of edges and vertices in planar undirected graphs. We show that
in the general case high vitality values are well approximated in time close to
the time currently required to compute $st$-max flow $O(n\log\log n)$. We also
give improved, and sometimes optimal, results in the case of integer
capacities. All our algorithms work in $O(n)$ space.
| [
"cs.DS"
] | cs.DS | Data Structures and Algorithms | 1,908Data Structures and Algorithms
|
|
2301.12861 | The spectral index images of the jet in the nearby radio galaxy M87 have
previously been shown with Very Long Baseline Interferometric arrays at 2-43
GHz. They exhibit flattening of the spectra at a location of inner (central)
spine and toward outer ridges. This could imply optical depth effects, lower
energy cutoff or stratification of the emitting particles energy distribution.
In this paper we employ simulations of multifrequency VLBI observations of M87
radio jet with various model brightness distributions. CLEAN deconvolution
errors produce significant features in the observed images. For intensity
images they result in the appearance of the inner ridge line in the
intrinsically edge brightened jet models. For spectral index images they
flatten the spectra in a series of stripes along the jet. Another bias
encountered in our simulations is steepening of the spectra in a low surface
brightness jet regions. These types of the imaging artefacts do not depend on
the model considered. We propose a methods for the compensation of the
systematics using only the observed data.
| [
"astro-ph.GA",
"astro-ph.IM"
] | astro-ph.GA | astro-ph.IM | Astrophysics of Galaxies;Instrumentation and Methods for Astrophysics | 495Astrophysics of Galaxies;Instrumentation and Methods for Astrophysics
|
2306.08749 | Despite the reduction in turn-around times in radiology reports with the use
of speech recognition software, persistent communication errors can
significantly impact the interpretation of the radiology report. Pre-filling a
radiology report holds promise in mitigating reporting errors, and despite
efforts in the literature to generate medical reports, there exists a lack of
approaches that exploit the longitudinal nature of patient visit records in the
MIMIC-CXR dataset. To address this gap, we propose to use longitudinal
multi-modal data, i.e., previous patient visit CXR, current visit CXR, and
previous visit report, to pre-fill the 'findings' section of a current patient
visit report. We first gathered the longitudinal visit information for 26,625
patients from the MIMIC-CXR dataset and created a new dataset called
Longitudinal-MIMIC. With this new dataset, a transformer-based model was
trained to capture the information from longitudinal patient visit records
containing multi-modal data (CXR images + reports) via a cross-attention-based
multi-modal fusion module and a hierarchical memory-driven decoder. In contrast
to previous work that only uses current visit data as input to train a model,
our work exploits the longitudinal information available to pre-fill the
'findings' section of radiology reports. Experiments show that our approach
outperforms several recent approaches. Code will be published at
https://github.com/CelestialShine/Longitudinal-Chest-X-Ray.
| [
"cs.CL",
"cs.LG"
] | cs.CL | cs.LG | Computation and Language;Machine Learning | 1,237Computation and Language;Machine Learning
|
cond-mat/0210562 | We simulated a growth model in 1+1 dimensions in which particles are
aggregated according to the rules of ballistic deposition with probability p or
according to the rules of random deposition with surface relaxation (Family
model) with probability 1-p. For any p>0, this system is in the
Kardar-Parisi-Zhang (KPZ) universality class, but it presents a slow crossover
from the Edwards-Wilkinson class (EW) for small p. From the scaling of the
growth velocity, the parameter p is connected to the coefficient of the
nonlinear term of the KPZ equation, lambda, giving lambda ~ p^gamma, with gamma
= 2.1 +- 0.2. Our numerical results confirm the interface width scaling in the
growth regime as W ~ lambda^beta t^beta, and the scaling of the saturation time
as tau ~ lambda^(-1) L^z, with the expected exponents beta =1/3 and z=3/2 and
strong corrections to scaling for small lambda. This picture is consistent with
a crossover time from EW to KPZ growth in the form t_c ~ lambda^(-4) ~ p^(-8),
in agreement with scaling theories and renormalization group analysis. Some
consequences of the slow crossover in this problem are discussed and may help
investigations of more complex models.
| [
"cond-mat.stat-mech"
] | cond-mat.stat-mech | Statistical Mechanics | 6,821Statistical Mechanics
|
|
1804.02841 | We calculate the amplitudes of $b\to s$ transition in extension of the
Standard Model with $Wtb$ anomalous couplings. We found that i) there exist the
Ward identity violating terms in effective vertix of $b\to s\gamma$. The terms,
which come from the tensor parts of $Wtb$ anomalies, and can be canceled
exactly by introducing corresponding $Wtb\gamma$ interactions, ii) $Br(B_{s}
\to \mu^{+}\mu^{-})$ provides unique information on $\delta v_L$ which is set
to zero in top decay experiments, and stringent bounds on $v_R,\ g_L$ by
$Br(B\to X_s\gamma)$ are obtained.
| [
"hep-ph"
] | hep-ph | High Energy Physics - Phenomenology | 3,129High Energy Physics - Phenomenology
|
|
1510.06134 | Dome A in the Antarctic plateau is likely one of the best astronomical
observing sites on Earth. The first one of three Antarctic Survey Telescope
(AST3-1), a 50/68 cm Schmidt-like equatorial-mount telescope, is the first
trackable telescope of China operating in Antarctica and the biggest telescope
located in Antarctic inland. AST3-1 obtained huge amounts of data in 2012 and
we processed the time-series parts. Here we present light curves of 29 variable
stars identified from ten-day observations in 2012 with AST3-1, including 22
newly discovered variable stars. 23 of them are eclipsing binaries and the
others are pulsating stars. We present the properties of the 29 variable stars,
including the classifications, periods and magnitude ranges in i band. For the
17 eclipsing binaries, the phased light curves are presented with the orbital
period values well determined.
| [
"astro-ph.SR"
] | astro-ph.SR | Solar and Stellar Astrophysics | 6,668Solar and Stellar Astrophysics
|
|
1404.2284 | Observations indicate that our universe is characterized by a late-time
accelerating phase, possibly driven by a cosmological constant $\Lambda$, with
the dimensionless parameter $\Lambda L_P^2 \simeq 10^{-122}$, where $L_P = (G
\hbar /c^3)^{1/2}$ is the Planck length. In this review, we describe how the
emergent gravity paradigm provides a new insight and a possible solution to the
cosmological constant problem. After reviewing the necessary background
material, we identify the necessary and sufficient conditions for solving the
cosmological constant problem. We show that these conditions are naturally
satisfied in the emergent gravity paradigm in which (i) the field equations of
gravity are invariant under the addition of a constant to the matter Lagrangian
and (ii) the cosmological constant appears as an integration constant in the
solution. The numerical value of this integration constant can be related to
another dimensionless number (called CosMIn) that counts the number of modes
inside a Hubble volume that cross the Hubble radius during the radiation and
the matter dominated epochs of the universe. The emergent gravity paradigm
suggests that CosMIn has the numerical value $4 \pi$, which, in turn, leads to
the correct, observed value of the cosmological constant. Further, the emergent
gravity paradigm provides an alternative perspective on cosmology and
interprets the expansion of the universe itself as a quest towards holographic
equipartition. We discuss the implications of this novel and alternate
description of cosmology.
| [
"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
|
0908.2075 | Using the semi-classical method of Nikishov-Ritus (NR), the derivation of the
transition rate of the beamstrahlung process is reviewed. This method uses the
Bound Interaction Picture and the exact solutions of the Dirac equation in the
external field potential. For future linear colliders, the nominal machine
parameters are such that this external field can be considered to be a constant
crossed electromagnetic field. The Dirac equation solutions can be Fourier
transformed such that they are functions of Dirac gamma matrices, Airy
functions and the usual non-external field solution. The resultant analytic
form for the transition rate is the same as that obtained by the Quasiclassical
Operator (QO) method of Baier-Katkov which sets a limit of ultra-relativistic
electron and vanishingly small radiation angle. The NR calculation however also
exhibits a pole in the radiation angle for back-radiated photons. The removal
of this pole requires a further study of IR divergences within the Bound
Interaction Picture.
| [
"hep-th"
] | hep-th | High Energy Physics - Theory | 3,266High Energy Physics - Theory
|
|
physics/0507097 | A method of measuring time intervals by a single observer proposed by Crowell
is extended to the more general case when the events separated by the time
interval take place at two points characterized by the same y=y' space
coordinates. We show that time dilation and time contraction can take place or
even an inversion in the time succession can be detected
| [
"physics.gen-ph"
] | physics.gen-ph | General Physics | 2,645General Physics
|
|
0710.4132 | Using a uniform analysis procedure, we measure spatially resolved weak
gravitational lensing and hydrostatic X-ray masses for a sample of 18 clusters
of galaxies. We find a radial trend in the X-ray to lensing mass ratio: at
r2500 we obtain a ratio MX/ML=1.03+/-0.07 which decreases to MX/ML=0.78+/-0.09
at r500. This difference is significant at 3 sigma once we account for
correlations between the measurements. We show that correcting the lensing mass
for excess correlated structure outside the virial radius slightly reduces, but
does not eliminate this trend. An X-ray mass underestimate, perhaps due to
nonthermal pressure support, can explain the residual trend. The trend is not
correlated with the presence or absence of a cool core. We also examine the
cluster gas fraction and find no correlation with ML, an important result for
techniques that aim to determine cosmological parameters using the gas
fraction.
| [
"astro-ph"
] | astro-ph | Astrophysics | 463Astrophysics
|
|
2302.01590 | We show that ferromagnetic interactions can enhance the adiabatic performance
of a quantum spin chain engine at low temperatures. The enhancement in work
output is particular pronounced, increasing exponentially with interaction
strength. The performance enhancement occurs in the paramagnetic phase and is
qualitatively explained by considering just the ground and first excited state,
in which case the system exhibits bipartite entanglement. As the temperature is
increased, thermal occupation of higher energy levels diminishes performance.
We find that these thermal fluctuations are smallest for long-range
interactions, resulting in the highest efficiency. Diabatic work extraction
degrades performance due to quantum friction. We identify an approximate,
experimentally realisable counterdiabatic drive that can mitigate friction for
weak interactions.
| [
"quant-ph",
"cond-mat.quant-gas"
] | quant-ph | cond-mat.quant-gas | Quantum Physics;Quantum Gases | 6,169Quantum Physics;Quantum Gases
|
0812.3542 | (abridged) In this paper we derive observed and modelled shape parameters
(apparent ellipticity and orientation of the ellipse) of 650 Galactic open
clusters identified in the ASCC-2.5 catalogue. We provide the observed shape
parameters of Galactic open clusters, computed with the help of a
multi-component analysis. For the vast majority of clusters these parameters
are determined for the first time. High resolution ("star by star") N-body
simulations are carried out with the specially developed $\phi$GRAPE code
providing models of clusters of different initial masses, Galactocentric
distances and rotation velocities. The comparison of models and observations of
about 150 clusters reveals ellipticities of observed clusters which are too low
(0.2 vs. 0.3), and offers the basis to find the main reason for this
discrepancy. The models predict that after $\approx 50$ Myr clusters reach an
oblate shape with an axes ratio of $1.65:1.35:1$, and with the major axis
tilted by an angle of $q_{XY} \approx 30^\circ$ with respect to the
Galactocentric radius due to differential rotation of the Galaxy. Unbiased
estimates of cluster shape parameters require reliable membership determination
in large cluster areas up to 2-3 tidal radii where the density of cluster stars
is considerably lower than the background. Although dynamically bound stars
outside the tidal radius contribute insignificantly to the cluster mass, their
distribution is essential for a correct determination of cluster shape
parameters. In contrast, a restricted mass range of cluster stars does not play
such a dramatic role, though deep surveys allow to identify more cluster
members and, therefore, to increase the accuracy of the observed shape
parameters.
| [
"astro-ph"
] | astro-ph | Astrophysics | 463Astrophysics
|
|
2009.01413 | Antiproton-nucleon ($\bar{p}N$) total cross sections are typically 3-4 times
larger than the $NN$ ones at incident energies from a few hundreds to thousands
MeV. We investigate antiproton-nucleus scattering as it could work as a probe
of the nuclear structure giving the sensitivity differently from a proton
probe. High-energy antiproton-nucleus reactions are reasonably described by the
Glauber model with a minimal profile function that reproduces the $\bar{p}N$
and $\bar{p}$-$^{12}$C cross section data. In contrast to the proton-nucleus
scattering, we find that the complete absorption occurs even beyond the nuclear
radius due to the large $\bar{p}N$ elementary cross sections, which shows
stronger sensitivity to the nuclear density distribution in the tail region.
This sensitivity is quantified in the total reaction cross sections with
various density profiles for future measurement including neutron-rich unstable
nuclei.
| [
"nucl-th"
] | nucl-th | Nuclear Theory | 4,876Nuclear Theory
|
|
1103.1438 | A recent detection of the peculiar neutron star X-ray binary Circinus X-1
with electronic very long baseline interferometry (e-VLBI) prompted the
suggestion that compact, non-variable radio emission persists through the
entire 16.6-day orbit of the binary system. We present the results of a high
angular resolution monitoring campaign conducted with the Australian Long
Baseline Array in real-time e-VLBI mode. e-VLBI observations of Circinus X-1
were made on alternate days over a period of 20 days covering the full binary
orbit. A compact radio source associated with Circinus X-1 was clearly detected
at orbital phases following periastron passage but no compact radio emission
was detected at any other orbital phase, ruling out the presence of a
persistent, compact emitting region at our sensitivity levels. The jet was not
resolved at any epoch of our 1.4-GHz monitoring campaign, suggesting that the
ultrarelativistic flow previously inferred to exist in this source is likely to
be dark. We discuss these findings within the context of previous radio
monitoring of Circinus X-1.
| [
"astro-ph.HE"
] | astro-ph.HE | High Energy Astrophysical Phenomena | 2,990High Energy Astrophysical Phenomena
|
|
1406.2950 | In this paper, we consider the problem of optimal reinsurance design, when
the risk is measured by a distortion risk measure and the premium is given by a
distortion risk premium. First, we show how the optimal reinsurance design for
the ceding company, the reinsurance company and the social planner can be
formulated in the same way. Second, by introducing the marginal indemnification
functions, we characterize the optimal reinsurance contracts. We show that, for
an optimal policy, the associated marginal indemnification function only takes
the values zero and one. We will see how the roles of the market preferences
and premiums and that of the total risk are separated.
| [
"q-fin.RM",
"math.PR"
] | q-fin.RM | math.PR | Risk Management;Probability | 6,322Risk Management;Probability
|
0810.0225 | Let $f(x)=x^5+ax^3+bx^2+cx \in \Z[x]$ and consider the hypersurface of degree
five given by the equation \cal{V}_{f}: f(p)+f(q)=f(r)+f(s). Under the
assumption $b\neq 0$ we show that there exists $\Q$-unirational elliptic
surface contained in $\cal{V}_{f}$. If $b=0, a<0$ and $-a\not\equiv 2,18,34
\pmod {48}$ then there exists $\Q$-rational surface contained in $\cal{V}_{f}$.
Moreover, we prove that for each $f$ of degree five there exists
$\Q(i)$-rational surface contained in $\cal{V}_{f}$.
| [
"math.NT"
] | math.NT | Number Theory | 4,945Number Theory
|
|
2002.01962 | The main goal of this paper is to analyze a family of "simplest possible"
initial data for which, as shown by numerical simulations, the incompressible
Euler equations have multiple solutions. We take here a first step toward a
rigorous validation of these numerical results. Namely, we consider the system
of equations corresponding to a self-similar solution, restricted to a bounded
domain with smooth boundary. Given an approximate solution obtained via a
finite dimensional Galerkin method, we establish a posteriori error bounds on
the distance between the numerical approximation and the exact solution having
the same boundary data.
| [
"math.AP"
] | math.AP | Analysis of PDEs | 205Analysis of PDEs
|
|
1403.4006 | This work is dedicated to investigation of galaxies that do not fit into a
common scenario of galaxy formation - isolated lenticular galaxies. We have
studied stellar populations and ionized gas content of a sample of 22
lenticular galaxies (among those 4 targets have appeared to be of erroneous
morphological classification) by undertaking deep long-slit spectroscopy with
the Russian 6-m telescope and with the Southern African Large Telescope (SALT).
The obtained average ages of the stellar populations in bulges and discs covers
a wide range between 1.5 and >15 Gyr, that indicates the absence of distinct
epoch of their stellar content formation. In contrast to galaxies in groups and
clusters, the stellar population ages in bulges and discs of isolated
lenticulars tend to be equal, that supports the inefficiency of the bulge
rejuvenation in sparse environment. Almost all the lenses and rings possess
intermediate ages of the stellar populations, within the range of 2-5 Gyr. By
analyzing the emission-line spectra of galaxies, we have found that 13 out of
18 (72+/-11 %) objects of our sample possess extended emission-line structures;
among those, 6 galaxies (46+/-14 %) demonstrate decoupled gas kinematics with
respect to their stellar discs. We have found starforming off-nuclear regions
in 10 galaxies; their gas oxygen abundances are nearly solar that implies tidal
gas accretion from gas-rich dwarf satellites rather than accretion from
cosmological large-scale structure filaments.
| [
"astro-ph.GA",
"astro-ph.CO"
] | astro-ph.GA | astro-ph.CO | Astrophysics of Galaxies;Cosmology and Nongalactic Astrophysics | 470Astrophysics of Galaxies;Cosmology and Nongalactic Astrophysics
|
1011.6251 | During the last twenty years there have been considerable methodological
developments in the design and analysis of Phase 1, Phase 2 and Phase 1/2
dose-finding studies. Many of these developments are related to the continual
reassessment method (CRM), first introduced by O'Quigley, Pepe and Fisher
(\citeyearQPF1990). CRM models have proven themselves to be of practical use
and, in this discussion, we investigate the basic approach, some connections to
other methods, some generalizations, as well as further applications of the
model. We obtain some new results which can provide guidance in practice.
| [
"stat.ME"
] | stat.ME | Methodology | 4,557Methodology
|
|
0806.3386 | We aim to extend and test the classifiers presented in a previous work
against an independent dataset. We complement the assessment of the validity of
the classifiers by applying them to the set of OGLE light curves treated as
variable objects of unknown class. The results are compared to published
classification results based on the so-called extractor methods.Two
complementary analyses are carried out in parallel. In both cases, the original
time series of OGLE observations of the Galactic bulge and Magellanic Clouds
are processed in order to identify and characterize the frequency components.
In the first approach, the classifiers are applied to the data and the results
analyzed in terms of systematic errors and differences between the definition
samples in the training set and in the extractor rules. In the second approach,
the original classifiers are extended with colour information and, again,
applied to OGLE light curves. We have constructed a classification system that
can process huge amounts of time series in negligible time and provide reliable
samples of the main variability classes. We have evaluated its strengths and
weaknesses and provide potential users of the classifier with a detailed
description of its characteristics to aid in the interpretation of
classification results. Finally, we apply the classifiers to obtain object
samples of classes not previously studied in the OGLE database and analyse the
results. We pay specific attention to the B-stars in the samples, as their
pulsations are strongly dependent on metallicity.
| [
"astro-ph"
] | astro-ph | Astrophysics | 463Astrophysics
|
|
2110.14558 | We performed a Penning trap mass measurement of $^{61}{\rm Zn}$ at the
National Superconducting Cyclotron Laboratory and NuShellX calculations of the
$^{61}{\rm Zn}$ and $^{62}{\rm Ga}$ structure using the GXPF1A Hamiltonian to
obtain improved estimates of the $^{61}{\rm Zn}(p,\gamma)^{62}{\rm Ga}$ and
$^{60}{\rm Cu}(p,\gamma)^{61}{\rm Zn}$ reaction rates. Surveying astrophysical
conditions for type-I X-ray bursts with the code MESA, implementing our
improved reaction rates, and taking into account updated nuclear masses for
$^{61}{\rm V}$ and $^{61}{\rm Cr}$ from the recent literature, we refine the
neutrino luminosity from the important mass number $A=61$ urca cooling source
in accreted neutron star crusts. This improves our understanding of the thermal
barrier between deep heating in the crust and the shallow depths where extra
heat is needed to explain X-ray superbursts, as well as the expected signature
of crust urca neutrino emission in light curves of cooling transients.
| [
"nucl-ex",
"nucl-th"
] | nucl-ex | nucl-th | Nuclear Experiment;Nuclear Theory | 4,873Nuclear Experiment;Nuclear Theory
|
2102.12268 | In this paper, we consider the renormalization operator $\mathcal R$ for
multimodal maps. We prove the renormalization operator $\mathcal R$ is a
self-homeomorphism on any totally $\mathcal R$-invariant set. As a corollary,
we prove the existence of the full renormalization horseshoe for multimodal
maps.
| [
"math.DS"
] | math.DS | Dynamical Systems | 2,265Dynamical Systems
|
|
2006.10323 | We report on the experimental observation of a simultaneous threefold
wavelength and spatial conversion process at telecommunication wavelengths
taking place in a 6-LP-mode graded-index few-mode fiber. The physical mechanism
is based on parallel and phase-matched frequency-degenerated intermodal
four-wave mixing (FD-IFWM) phenomena occurring between the fundamental mode and
higher-order spatial modes. More precisely, a single high-power
frequency-degenerated pump wave is simultaneously injected in the four spatial
modes LP01, LP11, LP02 and LP31 of a 1.8-km long graded-index few-mode fiber
together with three independent signals in the fundamental mode. By means of
three parallel phase-matched FD-IFWM interactions, these initial signals are
then simultaneously spatially and frequency converted from the fundamental mode
to specific high-order modes. The influence of the differential modal group
delay is also investigated and shows that the walk-off between the spatially
multiplexed signals significantly limits the bandwidth of the conversion
process for telecom applications.
| [
"physics.optics"
] | physics.optics | Optics | 5,146Optics
|
|
1806.04355 | The C and C++ programming languages are notoriously insecure yet remain
indispensable. Developers therefore resort to a multi-pronged approach to find
security issues before adversaries. These include manual, static, and dynamic
program analysis. Dynamic bug finding tools --- henceforth "sanitizers" --- can
find bugs that elude other types of analysis because they observe the actual
execution of a program, and can therefore directly observe incorrect program
behavior as it happens.
A vast number of sanitizers have been prototyped by academics and refined by
practitioners. We provide a systematic overview of sanitizers with an emphasis
on their role in finding security issues. Specifically, we taxonomize the
available tools and the security vulnerabilities they cover, describe their
performance and compatibility properties, and highlight various trade-offs.
| [
"cs.CR",
"cs.PL"
] | cs.CR | cs.PL | Cryptography and Security;Programming Languages | 1,857Cryptography and Security;Programming Languages
|
1909.12074 | This paper consists of a translation of Andre Tacquet's discussion of the
question of sizes of stars in a heliocentric universe, as published in his
posthumous Opera Mathematica of 1668, along with introductory material and
analysis. While Robert Hooke mentions Tacquet as one of the "great
Anti-copernicans", who argued the question of star sizes against the
heliocentric theory with "great vehemency and insulting", Tacquet's discussion
has received only scant attention. The kernel of Tacquet's argument is that the
absence of any detectable parallax in the stars, combined with the measured
apparent sizes of the stars, means that, in a heliocentric universe, the sizes
of stars compare to the size of Earth's orbit via the same proportion that they
compare to the size of the Earth in a geocentric universe. The translated
material presents this argument in a straightforward manner, insulting absent.
| [
"physics.hist-ph"
] | physics.hist-ph | History and Philosophy of Physics | 3,447History and Philosophy of Physics
|
|
1503.08794 | This letter discusses phenomenological aspects of dimensional reduction
predicted by the Causal Dynamical Triangulations (CDT) approach to quantum
gravity. The deformed form of the dispersion relation for the fields defined on
the CDT space-time is reconstructed. Using the Fermi satellite observations of
the GRB 090510 source we find that the energy scale of the dimensional
reduction is $E_* > 0.7 \sqrt{4-d_{\rm UV}} \cdot 10^{10}$ GeV at (95 $\%$ CL),
where $d_{\rm UV}$ is the value of the spectral dimension in the UV limit. By
applying the deformed dispersion relation to the cosmological perturbations it
is shown that, for a scenario when the primordial perturbations are formed in
the UV region, the scalar power spectrum $\mathcal{P}_S \propto k^{n_S-1}$
where $n_S-1\approx \frac{3 r (d_{\rm UV}-2)}{(d_{\rm UV}-1)r-48}$. Here, $r$
is the tensor-to-scalar ratio. We find that within the considered model, the
predicted from CDT deviation from the scale-invariance ($n_S=1$) is in
contradiction with the up to date Planck and BICEP2 data.
| [
"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
|
1611.05229 | We present the theory of time-dependent point transformations to find
independent dynamical normal modes for 2D systems subjected to time-dependent
control in the limit of small oscillations. The condition that determines if
the independent modes can indeed be defined is identified, and a geometrical
analogy is put forward. The results explain and unify recent work to design
fast operations on trapped ions, needed to implement a scalable
quantum-information architecture: transport, expansions, and the separation of
two ions, two-ion phase gates, as well as the rotation of an anisotropic trap
for an ion are treated and shown to be analogous to a mechanical system of two
masses connected by springs with time dependent stiffness.
| [
"quant-ph"
] | quant-ph | Quantum Physics | 5,985Quantum Physics
|
|
2109.09193 | This paper explores zero-label learning in Natural Language Processing (NLP),
whereby no human-annotated data is used anywhere during training and models are
trained purely on synthetic data. At the core of our framework is a novel
approach for better leveraging the powerful pretrained language models.
Specifically, inspired by the recent success of few-shot inference on GPT-3, we
present a training data creation procedure named Unsupervised Data Generation
(UDG), which leverages few-shot prompts to synthesize high-quality training
data without real human annotations. Our method enables zero-label learning as
we train task-specific models solely on the synthetic data, yet we achieve
better or comparable results from strong baseline models trained on
human-labeled data. Furthermore, when mixed with labeled data, our approach
serves as a highly effective data augmentation procedure, achieving new
state-of-the-art results on the SuperGLUE benchmark.
| [
"cs.CL",
"cs.LG"
] | cs.CL | cs.LG | Computation and Language;Machine Learning | 1,237Computation and Language;Machine Learning
|
cond-mat/9605178 | We investigate the spin and charge susceptibilities of the two-dimensional
Hubbard model based upon the perturbative calculation in the strength of
correlation $U$. For $U$ comparable to a bare bandwidth, the charge
susceptibility decreases near the half-filling as hole-doping approaches zero.
This behavior suggesting the precursor of the Mott-Hubbard gap formation cannot
be obtained without the vertex corrections beyond the random phase
approximation. In the low-temperature region, the spin susceptibility deviates
from the Curie-Weiss-like law and finally turns to decrease with the decrease
of temperature. This spin-gap-like behavior is originating from the van Hove
singularity in the density of states.
| [
"cond-mat"
] | cond-mat | Condensed Matter | 1,697Condensed Matter
|
|
2007.10469 | Deep learning approaches have recently shown great promise in accelerating
magnetic resonance image (MRI) acquisition. The majority of existing work have
focused on designing better reconstruction models given a pre-determined
acquisition trajectory, ignoring the question of trajectory optimization. In
this paper, we focus on learning acquisition trajectories given a fixed image
reconstruction model. We formulate the problem as a sequential decision process
and propose the use of reinforcement learning to solve it. Experiments on a
large scale public MRI dataset of knees show that our proposed models
significantly outperform the state-of-the-art in active MRI acquisition, over a
large range of acceleration factors.
| [
"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
|
physics/0208075 | The evolution of two colliding beams in a linear accelerator can be described
by two coupled Vlasov equations. In PEP-NOTE-325 by S. Kheifets and A. W. Chao
the case without external focusing was considered. In this paper we derive the
equilibrium distribution and the tune shift in the presence of external
focusing. Motion is considered only in the vertical direction and the beams are
presumed to be one-dimensional.
| [
"physics.acc-ph"
] | physics.acc-ph | Accelerator Physics | 0Accelerator Physics
|
|
2103.04865 | We find a new class of exact solutions in the Einstein-Maxwell theory by
employing the Ernst magnetization process to the Kerr-Newman-Taub-NUT
spacetimes. We study the solutions and find that they are regular everywhere.
We also find the quasilocal conserved quantities for the spacetimes, the
corresponding Smarr formula and the first law of thermodynamics.
| [
"gr-qc"
] | gr-qc | General Relativity and Quantum Cosmology | 2,674General Relativity and Quantum Cosmology
|
|
2106.05127 | In this paper, we focus on the fairness issues regarding unsupervised outlier
detection. Traditional algorithms, without a specific design for algorithmic
fairness, could implicitly encode and propagate statistical bias in data and
raise societal concerns. To correct such unfairness and deliver a fair set of
potential outlier candidates, we propose Deep Clustering based Fair Outlier
Detection (DCFOD) that learns a good representation for utility maximization
while enforcing the learnable representation to be subgroup-invariant on the
sensitive attribute. Considering the coupled and reciprocal nature between
clustering and outlier detection, we leverage deep clustering to discover the
intrinsic cluster structure and out-of-structure instances. Meanwhile, an
adversarial training erases the sensitive pattern for instances for fairness
adaptation. Technically, we propose an instance-level weighted representation
learning strategy to enhance the joint deep clustering and outlier detection,
where the dynamic weight module re-emphasizes contributions of likely-inliers
while mitigating the negative impact from outliers. Demonstrated by experiments
on eight datasets comparing to 17 outlier detection algorithms, our DCFOD
method consistently achieves superior performance on both the outlier detection
validity and two types of fairness notions in outlier detection.
| [
"cs.LG",
"cs.CY"
] | cs.LG | cs.CY | Machine Learning;Computers and Society | 4,070Machine Learning;Computers and Society
|
1301.2161 | The low-frequency and shot noises in spin-valve CoFeB/MgO/CoFeB magnetic
tunneling junctions were studied at low temperature. The measured 1/f noise
around the magnetic hysteresis loops of the free layer indicates that the main
origin of the 1/f noise is the magnetic fluctuation, which is discussed in
terms of a fluctuation-dissipation relation. Random telegraph noise (RTN) is
observed to be symmetrically enhanced in the hysteresis loop with regard to the
two magnetic configurations. We found that this enhancement is caused by the
fluctuation between two magnetic states in the free layer. Although the 1/f
noise is almost independent of the magnetic configuration, the RTN is enhanced
in the antiparallel configuration. These findings indicate the presence of
spin-dependent activation of RTN. Shot noise reveals the spin-dependent
coherent tunneling process via a crystalline MgO barrier.
| [
"cond-mat.mes-hall"
] | cond-mat.mes-hall | Mesoscale and Nanoscale Physics | 4,450Mesoscale and Nanoscale Physics
|
|
astro-ph/9409075 | We use the semi-analytic models of galaxy formation developed by Kauffmann,
White \& Guiderdoni to generate predictions for the observed properties of
cluster and group galaxies at redshifts between 0 and 0.6. We examine four sets
of cosmological initial conditions: low-density CDM models with and without
cosmological constant, a flat CDM model and a mixed dark matter model. These
models were selected because they span a wide range in cluster formation epoch.
The semi-analytic models that we employ are able to follow both the evolution
of the dark matter component of clusters and the formation and evolution of the
stellar populations of the cluster galaxies. We are thus able to generate model
predictions that can be compared directly with the observational data. In the
low-density CDM models, clusters form at high red- shift and accrete very
little mass at recent times. Our models predict that essentially no evolution
in the observed properties of clusters will have occurred by a redshift of 0.6,
in direct contradiction with the data. In contrast, in the MDM model, both
galaxies and clusters form extremely late. This model predicts evolution which
appears to be too extreme to be in agreement with the observations. The flat
CDM model, which is intermediate in structure formation epoch, is most
successful. This model is able to account for the evolution of the blue
fraction of rich clusters with redshift, the relationship between blue fraction
and cluster richness at different epochs, and the changes in the distribution
of the morphologies of cluster galaxies by a redshift of 0.4.
| [
"astro-ph"
] | astro-ph | Astrophysics | 463Astrophysics
|
|
1502.00790 | We develop a theory of extensions for involutive and nondegenerate solutions
of the set-theoretic Yang-Baxter equation and use it to produce new families of
solutions. As an application we construct an infinite family of counterexamples
to a conjecture of Gateva-Ivanova related to the retractability of square-free
solutions.
| [
"math.QA",
"math.GR"
] | math.QA | math.GR | Quantum Algebra;Group Theory | 5,895Quantum Algebra;Group Theory
|
2105.08045 | In warm inflation, dissipation due to the interactions of the inflaton field
to other light degrees of freedom leads naturally to the enhancement of the
primordial spectrum during the last 10-20 efolds of inflation. We study this
effect in a variant of the Warm Little Inflaton model, where the inflaton
couples to light scalars, with a quartic chaotic potential. These large
fluctuations on re-entry will form light, evaporating Primordial Black Holes,
with masses lighter than $10^6$ g. But at the same time they will act as a
source for the tensors at second order. The enhancement is maximal near the end
of inflation, which result in a spectral density of Gravitational Waves (GW)
peaked at frequencies $f \sim O(10^3-10^5)$ Hz today, and with an amplitude
$\Omega_{GW} \sim 10^{-10}-10^{-8}$. Although the frequency range is outside
the reach of present and planned GW detectors, it might be reached in future
high-frequency gravitational waves detectors, designed to search for
cosmological stochastic GW backgrounds above MHz frequencies.
| [
"hep-ph",
"astro-ph.CO",
"gr-qc"
] | hep-ph | astro-ph.CO | High Energy Physics - Phenomenology;Cosmology and Nongalactic Astrophysics;General Relativity and Quantum Cosmology | 3,160High Energy Physics - Phenomenology;Cosmology and Nongalactic Astrophysics;General Relativity and Quantum Cosmology
|
1712.06525 | The evolution of lithium abundance over a star's lifetime is indicative of
transport processes operating in the stellar interior. We revisit the
relationship between lithium content and rotation rate previously reported for
cool dwarfs in the Pleiades cluster. We derive new LiI 670.8 nm equivalent
width measurements from high-resolution spectra obtained for low-mass Pleiades
members. We combine these new measurements with previously published ones, and
use the Kepler/K2 rotational periods recently derived for Pleiades cool dwarfs
to investigate the lithium-rotation connection in this 125 Myr-old cluster. The
new data confirm the correlation between lithium equivalent width and stellar
spin rate for a sample of 51 early K-type members of the cluster, where fast
rotating stars are systematically lithium-rich compared to slowly rotating
ones. The correlation is valid for all stars over the (J-Ks) color range
0.50-0.70 mag, corresponding to a mass range from about 0.75 to 0.90 solar
mass, and may extend down to lower masses. We argue that the dispersion in
lithium equivalent widths observed for cool dwarfs in the Pleiades cluster
reflects an intrinsic scatter in lithium abundances, and suggest that the
physical origin of the lithium dispersion pattern is to be found in the
pre-main sequence rotational history of solar-type stars.
| [
"astro-ph.SR"
] | astro-ph.SR | Solar and Stellar Astrophysics | 6,668Solar and Stellar Astrophysics
|
|
2104.06686 | We present an approach for automated in-situ monitoring of phytoplankton and
zooplankton communities based on a dual magnification dark-field imaging
microscope/camera. We describe the Dual Scripps Plankton Camera (DSPC) system
and associated image processing, and assess its capabilities in detecting and
characterizing plankton species of different size and taxonomic categories, and
in measuring their abundances in both laboratory and field applications. In the
laboratory, body size and abundance estimates by the DSPC significantly and
robustly scale with the same measurements derived by traditional microscopy. In
the field, a DSPC installed permanently at 3 m depth in Lake Greifensee
(Switzerland), delivered images of plankton individuals, colonies, and
heterospecific aggregates without disrupting natural arrangements of
interacting organisms, their microenvironment or their behavior at hourly
timescales. The DSPC was able to track the dynamics of taxa in the size range
between ~10 $\mu$m to ~ 1 cm, covering virtually all the components of the
planktonic food web (including parasites and potentially toxic cyanobacteria).
Comparing data from the field-deployed DSPC to traditional sampling and
microscopy revealed a general overall agreement in estimates of plankton
diversity and abundances, despite imaging limitations in detecting small
phytoplankton species and rare and large zooplankton taxa (e.g. carnivorous
zooplankton). The most significant disagreements between traditional methods
and the DSPC resided in the measurements of community properties of
zooplankton, organisms that are heterogeneously distributed spatially and
temporally, and whose demography appeared to be better captured by automated
imaging. Time series collected by the DSPC depicted ecological succession
patterns, algal bloom dynamics and circadian fluctuations with a temporal
frequency and morphological [continues...]
| [
"q-bio.PE",
"physics.ins-det"
] | q-bio.PE | physics.ins-det | Populations and Evolution;Instrumentation and Detectors | 7,267longtail
|
1507.04386 | The unknotting number of a knot is the minimum number of crossings one must
change to turn that knot into the unknot. The algebraic unknotting number is
the minimum number of crossing changes needed to transform a knot into an
Alexander polynomial-one knot. We work with a generalization of unknotting
number due to Mathieu-Domergue, which we call the untwisting number. The
untwisting number is the minimum number (over all diagrams of a knot) of right-
or left-handed twists on even numbers of strands of a knot, with half of the
strands oriented in each direction, necessary to transform that knot into the
unknot. We show that the algebraic untwisting number is equal to the algebraic
unknotting number. However, we also exhibit several families of knots for which
the difference between the unknotting and untwisting numbers is arbitrarily
large, even when we only allow twists on a fixed number of strands or fewer.
| [
"math.GT"
] | math.GT | Geometric Topology | 2,813Geometric Topology
|
|
2003.04669 | The Leggett inequality is a constraint on the bipartite correlation that
admits certain types of non-localities. Existing tests mainly focused on the
electromagnetic systems where measurement apparatus are assumed to be
projective and sharp. However, in nature there are interactions that do not
obey the same conservation laws for photon, and the actual measurements may
subject to unavoidable uncertainties due to the fundamental physical
principles. In this work, we generalize the Leggett inequality to incorporate
the measurements that are unsharp and/or biased. It is found that the parity
violation in nature provides a spontaneous implementation of an unsharp
measurement for the spin of hyperon. A fine structured Leggett inequality for
hyperon decays characterized by the asymmetry parameters is obtained and its
violation is found which could be observed with the yet obtained data in
experiment, like BESIII and Belle.
| [
"quant-ph",
"hep-ph"
] | quant-ph | hep-ph | Quantum Physics;High Energy Physics - Phenomenology | 6,087Quantum Physics;High Energy Physics - Phenomenology
|
1207.7126 | In this paper we study the relationship between the extended symmetries of
exact Courant algebroids over a manifold $M$, defined by Bursztyn, Cavalcanti
and Gualtieri, and the Poisson algebras of admissible functions associated to
twisted Dirac structures when acted by Lie groups. We show that the usual
homomorphisms of Lie algebras between the algebras of infinitesimal symmetries
of the action, vector fields on the manifold and the Poisson algebra of
observables, appearing in symplectic geometry, generalize to natural maps of
Leibniz algebras induced both by the extended action and compatible moment maps
associated to it in the context of twisted Dirac structures.
| [
"math.SG"
] | math.SG | Symplectic Geometry | 7,123Symplectic Geometry
|
|
1710.07473 | Transform Invariant Low-Rank Textures, referred to as TILT, can accurately
and robustly extract textural or geometric information in a 3D from
user-specified windows in 2D in spite of significant corruptions and warping.
It was discovered that the task can be characterized, both theoretically and
numerically, by solving a sequence of matrix nuclear-norm and $\ell_1$-norm
involved convex minimization problems. For solving this problem, the direct
extension of Alternating Direction Method of Multipliers (ADMM) in an usual
Gauss-Seidel manner often performs numerically well in practice but there is no
theoretical guarantee on its convergence. In this paper, we resolve this
dilemma by using the novel symmetric Gauss-Seidel (sGS) based ADMM developed by
Li, Sun \& Toh (Math. Prog. 2016). The sGS-ADMM is guaranteed to converge and
we shall demonstrate in this paper that it is also practically efficient than
the directly extended ADMM. When the sGS technique is applied to this
particular problem, we show that only one variable needs to be re-updated, and
this updating hardly imposes any excessive computational cost. The sGS
decomposition theorem of Li, Sun \& Toh (arXiv: 1703.06629) establishes the
equivalent between sGS-ADMM and the classical ADMM with an additional
semi-proximal term, so the convergence result is followed directly. Extensive
experiments illustrate that the sGS-ADMM and its generalized variant have
superior numerical efficiency over the directly extended ADMM.
| [
"math.OC"
] | math.OC | Optimization and Control | 5,234Optimization and Control
|
|
2103.01190 | The problem of stability of the optimal filter is revisited. The optimal
filter (or filtering process) is the conditional probability of the current
state of some stochastic process (the signal process), given both present and
past values of another process (the observation process). Typically the
filtering process satisfies a dynamical equation, and the question investigated
here concerns the stability of this dynamics. In contrast to previous work,
signal processes given by the iterations of a deterministic mapping $f$ are
considered, with only the initial condition being random. While the stability
of the filter may emerge from strong randomness of the signal processes,
different and more dynamical effects will be exploited in the present work.
More specifically, we consider uniformly hyperbolic $f$ with strong
instabilities providing the necessary mixing. This however requires that the
filtering process is initialised with densities exhibiting already a certain
level of smoothness. Furthermore, $f$ may also have stable directions along
which the filtering process will eventually not have a density, a major
technical difficulty. Further results show that the filtering process is
asymptotically concentrated on the attractor and furthermore will have
densities with respect to the invariant (SRB)~measure along instable manifolds
of $f$.
| [
"math.PR",
"math.DS"
] | math.PR | math.DS | Probability;Dynamical Systems | 5,748Probability;Dynamical Systems
|
2206.13501 | We show that bilayer graphene in the presence of a 2D superlattice potential
provides a highly tunable setup that can realize a variety of flat band
phenomena. We focus on two regimes: (i) topological flat bands with non-zero
Chern numbers, C, including bands with higher Chern numbers |C| > 1; and (ii)
an unprecedented phase consisting of a stack of nearly perfect flat bands with
C = 0. For realistic values of the potential and superlattice periodicity, this
stack can span nearly 100 meV, encompassing nearly all of the low-energy
spectrum. We further show that in the topological regime, the topological flat
band has a favorable band geometry for realizing a fractional Chern insulator
(FCI) and use exact diagonalization to show that the FCI is in fact the ground
state at 1/3 filling. Our results provide a realistic guide for future
experiments to realize a new platform for flat band phenomena.
| [
"cond-mat.mes-hall",
"cond-mat.mtrl-sci",
"cond-mat.str-el"
] | cond-mat.mes-hall | cond-mat.mtrl-sci | Mesoscale and Nanoscale Physics;Materials Science;Strongly Correlated Electrons | 4,512Mesoscale and Nanoscale Physics;Materials Science;Strongly Correlated Electrons
|
1612.02098 | We collected the multiplicity data of stars in Taurus to build an up-to-date
stellar/multiplicity catalog. After a general study of nearest-neighbor
statistics on spatial random distribution, we introduce the one-point
correlation $\Psi$ function to complement the pair correlation function and
define the spatial regimes departing from randomness in Taurus. We then perform
a set of statistical studies to characterize the binary regime that prevails in
Taurus. The $\Psi$ function in Taurus has a scale-free trend with a similar
exponent as the correlation function at small scale. It extends almost 3
decades up to $\sim 60$ kAU showing a potential extended wide binary regime.
This was hidden in the correlation function due to the clustering pattern
blending. Distinguishing two stellar populations, single stars versus multiple
systems (separation $ \leq 1$ kAU), within Class II/III stars observed at high
angular resolution, we highlight a major spatial neighborhood difference
between the two populations using nearest-neighbor statistics. The multiple
systems are three times more likely to have a distant companion within 10 kAU
when compared to single stars. We show that this is due to the presence of most
probable physical ultra-wide pairs. These UWPs are biased towards high
multiplicity and higher-stellar-mass components at shorter separations. The
multiplicity fraction per ultra-wide pair with separation less than 10 kAU may
be as high as 83.5 $\pm$ 19.6\%. We suggest that these young pre-main sequence
UWPs may be pristine imprints of their spatial configuration at birth resulting
from a cascade fragmentation scenario of the natal molecular core. They could
be the older counterparts, at least for those separated by less than 10 kAU, to
the $\le$ 0.5 Myr prestellar cores/Class 0 multiple objects observed at
radio/mm wavelengths.
| [
"astro-ph.SR",
"astro-ph.GA"
] | astro-ph.SR | astro-ph.GA | Solar and Stellar Astrophysics;Astrophysics of Galaxies | 6,669Solar and Stellar Astrophysics;Astrophysics of Galaxies
|
1007.3346 | In this short note, based on Carleman estimates and Holmgren's type theorems,
we provide a converse theorem of the classical Huygens principle for free wave
equations. Possible generalizations to other underlying space-times or other
wave type equations are also discussed.
| [
"math.AP"
] | math.AP | Analysis of PDEs | 205Analysis of PDEs
|
|
physics/0010018 | A current approach to the problem of inertia suggests that the origin of the
inertial properties of matter is the interaction between matter and vacuum
electromagnetic zero-point radiation. Herein, it is shown that zero-point
phenomena can be treated as the origin of inertia only when one chooses to
ignore the mass-energy content of matter. In the absence of any physical basis
for such a choice, it is concluded that zero-point-induced forces must arise in
addition to the intrinsic inertial properties of ordinary matter.
| [
"physics.gen-ph"
] | physics.gen-ph | General Physics | 2,645General Physics
|
|
2110.09052 | In this work, we calculate the higher mass spectra for the $2S$- and
$1D$-wave fully-charmed and fully-bottom tetraquark states in a nonrelativistic
potential quark model. The $2S$-wave fully-charmed/bottom tetraquark states lie
in the mass range of $\sim (6.9,7.1)$/$(19.7,19.9)$ GeV, apart for the highest
$0^{++}$ state $T_{(cc\bar{c}\bar{c})0^{++}}(7185)$/
$T_{(bb\bar{b}\bar{b})0^{++}}(19976)$. Most of the $2S$-wave states highly
overlap with the high-lying $1P$-wave states. The masses for the $1D$-wave
fully-charmed/bottom tetraquarks are predicted to be in the range of $\sim
(6.7,7.2)/(19.5,20.0)$ GeV. The mass range for the $D$-wave tetraquark states
cover most of the mass range of the $P$-wave states and the whole mass range of
the $2S$-wave states. The narrow structure $X(6900)$ recently observed at LHCb
in the di-$J/\psi$ invariant mass spectrum may be caused by the $1P$-, or
$2S$-, or $1D$-wave $T_{cc\bar{c}\bar{c}}$ states. The vague structure
$X(7200)$ may be caused by the highest $2S$-wave state
$T_{(cc\bar{c}\bar{c})0^{++}}(7185)$, two low-lying $3S$-wave states
$T_{(cc\bar{c}\bar{c})0^{++}}(7240)$ and $T_{(cc\bar{c}\bar{c})2^{++}}(7248)$,
and/or the high-lying $1D$-wave states with masses around 7.2 GeV and
$J^{PC}=0^{++},1^{++},2^{++},3^{++}$, or $4^{++}$. While it is apparent that
the potential quark model calculations predict more states than the structures
observed in the di-$J/\psi$ invariant mass spectrum, our calculations will help
further understanding of the properties of these fully-heavy tetraquark states
in their strong and magnetic interactions with open channels based on explicit
quark model wave functions.
| [
"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
|
2109.15317 | We present MetaUVFS as the first Unsupervised Meta-learning algorithm for
Video Few-Shot action recognition. MetaUVFS leverages over 550K unlabeled
videos to train a two-stream 2D and 3D CNN architecture via contrastive
learning to capture the appearance-specific spatial and action-specific
spatio-temporal video features respectively. MetaUVFS comprises a novel
Action-Appearance Aligned Meta-adaptation (A3M) module that learns to focus on
the action-oriented video features in relation to the appearance features via
explicit few-shot episodic meta-learning over unsupervised hard-mined episodes.
Our action-appearance alignment and explicit few-shot learner conditions the
unsupervised training to mimic the downstream few-shot task, enabling MetaUVFS
to significantly outperform all unsupervised methods on few-shot benchmarks.
Moreover, unlike previous few-shot action recognition methods that are
supervised, MetaUVFS needs neither base-class labels nor a supervised
pretrained backbone. Thus, we need to train MetaUVFS just once to perform
competitively or sometimes even outperform state-of-the-art supervised methods
on popular HMDB51, UCF101, and Kinetics100 few-shot datasets.
| [
"cs.CV",
"cs.AI",
"cs.LG"
] | cs.CV | cs.AI | Computer Vision and Pattern Recognition;Artificial Intelligence;Machine Learning | 1,521Computer Vision and Pattern Recognition;Artificial Intelligence;Machine Learning
|
nucl-th/9701042 | We show that lepton-pair production in Virtual Compton Scattering offers,
through interference with the well-known Bethe-Heitler process, a sensitive
probe to learn the longitudinal response of resonances and the electromagnetic
nucleon form factors. This interference can be measured directly in terms of an
asymmetry. The role of off-shell effects in the N-N-$\gamma$ vertices is
investigated as well. An additional N-N-$\gamma -\gamma$ contact term in the
amplitude, included to ensure gauge invariance of the model, cancels a
substantial part of the off-shell effects.
| [
"nucl-th"
] | nucl-th | Nuclear Theory | 4,876Nuclear Theory
|
|
1801.04874 | Ba(Ni$_{1-x}$Co$_x$)$_2$As$_2$ is a structural homologue of the pnictide high
temperature superconductor, Ba(Fe$_{1-x}$Co$_x$)$_2$As$_2$, in which the Fe
atoms are replaced by Ni. Superconductivity is highly suppressed in this
system, reaching a maximum $T_c$ = 2.3 K, compared to 24 K in its iron-based
cousin, and the origin of this $T_c$ suppression is not known. Using x-ray
scattering, we show that Ba(Ni$_{1-x}$Co$_x$)$_2$As$_2$ exhibits a
unidirectional charge density wave (CDW) at its triclinic phase transition. The
CDW is incommensurate, exhibits a sizable lattice distortion, and is
accompanied by the appearance of $\alpha$ Fermi surface pockets in
photoemission [B. Zhou et al., Phys. Rev. B 83, 035110 (2011)], suggesting it
forms by an unconventional mechanism. Co doping suppresses the CDW, paralleling
the behavior of antiferromagnetism in iron-based superconductors. Our study
demonstrates that pnictide superconductors can exhibit competing CDW order,
which may be the origin of $T_c$ suppression in this system.
| [
"cond-mat.str-el"
] | cond-mat.str-el | Strongly Correlated Electrons | 6,979Strongly Correlated Electrons
|
|
nucl-th/9306013 | It is argued that the transparency of a medium for passage of a nucleon,
knocked-out in a semi-inclusive $(e,e'p)$ reaction and subsequently scattered
elastically, is not the same as the one measured in purely elastic scattering.
Expressions are given for the properly generalized transparency and those are
compared with recently proposed, alternative suggestions. Numerical results are
presented for selected nuclear targets and kinematic conditions, applying to
the Garino et al and the SLAC NE18 experiment.
| [
"nucl-th"
] | nucl-th | Nuclear Theory | 4,876Nuclear Theory
|
|
hep-th/0404082 | We give general intersecting brane solutions without assuming any restriction
on the metric in supergravity coupled to a dilaton and antisymmetric tensor
fields in arbitrary dimensions $D$. The result is a general class of
intersecting brane solutions which interpolate the non-extreme solutions of
type 1 and 2. We also discuss the relation of our solutions to the known single
brane solution.
| [
"hep-th"
] | hep-th | High Energy Physics - Theory | 3,266High Energy Physics - Theory
|
|
1409.6880 | There are variety of methods to solve the localization problem and among them
semi-definite programming based methods have shown great performance in both
complexity and accuracy aspects. In this paper, we introduce a class of less
noise-sensitive relaxation to reduce the complexity of SDP-based methods. We
apply our relaxation to Edge-based Semi-Definite Programming (ESDP) method and
the resulted model is called PESDP. Simulation results confirm that our
proposed PESDP method is less noise-sensitive and faster compared to the
original ESDP.
| [
"math.OC"
] | math.OC | Optimization and Control | 5,234Optimization and Control
|
|
2108.00719 | Knowledgeable FAQ chatbots are a valuable resource to any organization. While
powerful and efficient retrieval-based models exist for English, it is rarely
the case for other languages for which the same amount of training data is not
available. In this paper, we propose a novel pre-training procedure to adapt
ConveRT, an English conversational retriever model, to other languages with
less training data available. We apply it for the first time to the task of
Dutch FAQ answering related to the COVID-19 vaccine. We show it performs better
than an open-source alternative in both a low-data regime and a high-data
regime.
| [
"cs.CL"
] | cs.CL | Computation and Language | 1,168Computation and Language
|
|
1307.1481 | It has been argued that, starting with a slightly sub-extremal Kerr black
hole instead of an extremal one, it is possible to overspin a black hole past
the extremal limit and turn it into a naked singularity by sending test bodies,
if one neglects radiative and self-force effects. In this work we show that (i)
an extremal Kerr black hole can not be overspun as a result of the interaction
with massless integer spin test fields (scalar, electromagnetic, or
gravitational), (ii) overspinning can be achieved if we start with a nearly
extremal black hole instead, and (iii) for the scalar field, the argument
applies to more general black holes, and also allows use of a more general
field configuration. Our analysis also neglects radiative and self-force
effects.
| [
"gr-qc"
] | gr-qc | General Relativity and Quantum Cosmology | 2,674General Relativity and Quantum Cosmology
|
|
quant-ph/0511025 | We study the weakest model of quantum nondeterminism in which a classical
proof has to be checked with probability one by a quantum protocol. We show the
first separation between classical nondeterministic communication complexity
and this model of quantum nondeterministic communication complexity for a total
function. This separation is quadratic.
| [
"quant-ph",
"cs.CC"
] | quant-ph | cs.CC | Quantum Physics;Computational Complexity | 6,017Quantum Physics;Computational Complexity
|
2302.09718 | This paper provides a systematic review of emerging control techniques used
for railway Virtual Coupling (VC) studies. Train motion models are first
reviewed, including model formulations and the force elements involved. Control
objectives and typical design constraints are then elaborated. Next, the
existing VC control techniques are surveyed and classified into five groups:
consensus-based control, model prediction control, sliding mode control,
machine learning-based control, and constraints-following control. Their
advantages and disadvantages for VC applications are also discussed in detail.
Furthermore, several future studies for achieving better controller development
and implementation, respectively, are presented. The purposes of this survey
are to help researchers to achieve a better systematic understanding regarding
VC control, to spark more research into VC and to further speed-up the
realization of this emerging technology in railway and other relevant fields
such as road vehicles.
| [
"math.NA",
"cs.NA"
] | math.NA | cs.NA | Numerical Analysis;Numerical Analysis | 5,059Numerical Analysis;Numerical Analysis
|
2008.05474 | Swampland conjectures have attracted quite some interest in the cosmological
community. They have been shown to have wide ranging implications , like
constraints on inflationary models, primordial black holes, dark energy to name
a few. Particularly, their implications on single field inflationary models in
general relativity based cosmology has gathered huge attention. Swampland
conjectures in their usual form have been shown to be incompatible with these
kind of single field models, or have been shown to induce severe fine tuning in
these inflationary models for them to be consistent with the conjectures. In
this work, we show that a large class of single field inflationary models can
in fact bypass the problems faced by inflationary paradigms in GR Based
cosmology. We use the exact solution approach to inflation for the same purpose
and show how string theoretic motivations of the swampland conjectures can be
in perfect symphony with various single field inflationary models in
non-standard cosmological scenarios.
| [
"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
|
astro-ph/9312048 | Radiation of both the outer gaps and the neutron star surface is considered
for a Vela-like pulsar near the death line. It is shown that if such a pulsar
is close enough to the death line, its optical, UV and X-ray emission has to
increase. Using results of this consideration, it is argued that Geminga is not
a close relative of Vela-like pulsars. The outer gap model of Geminga in which
the main part of the outer gap volume operates as a Vela-like generator of
$\gamma$-rays is ruled out. A Vela-like mechanism of $\gamma$-ray generation
can operate only in a small region of the outer gap of Geminga. The length of
this region along the magnetic field is an order of magnitude smaller than the
outer gap dimensions. In the magnetosphere of Geminga the main mechanism of
$\gamma$-ray generation at $\sim 10 - 10^4$ MeV is curvature radiation and not
the synchrotron radiation as it was assumed for Vela-like pulsars.
| [
"astro-ph"
] | astro-ph | Astrophysics | 463Astrophysics
|
|
1411.7364 | Background: While many infectious disease epidemics are initially
characterized by an exponential growth in time, we show that district-level
Ebola virus disease (EVD) outbreaks in West Africa follow slower
polynomial-based growth kinetics over several generations of the disease.
Methods: We analyzed epidemic growth patterns at three different spatial scales
(regional, national, and subnational) of the Ebola virus disease epidemic in
Guinea, Sierra Leone and Liberia by compiling publicly available weekly time
series of reported EVD case numbers from the patient database available from
the World Health Organization website for the period 05-Jan to 17-Dec 2014.
Results: We found significant differences in the growth patterns of EVD cases
at the scale of the country, district, and other subnational administrative
divisions. The national cumulative curves of EVD cases in Guinea, Sierra Leone,
and Liberia show periods of approximate exponential growth. In contrast, local
epidemics are asynchronous and exhibit slow growth patterns during 3 or more
EVD generations, which can be better approximated by a polynomial than an
exponential. Conclusions: The slower than expected growth pattern of local EVD
outbreaks could result from a variety of factors, including behavior changes,
success of control interventions, or intrinsic features of the disease such as
a high level of clustering. Quantifying the contribution of each of these
factors could help refine estimates of final epidemic size and the relative
impact of different mitigation efforts in current and future EVD outbreaks.
| [
"q-bio.PE"
] | q-bio.PE | Populations and Evolution | 5,627Populations and Evolution
|
|
2012.04443 | We present the Quantized Transformer (QT), an unsupervised system for
extractive opinion summarization. QT is inspired by Vector-Quantized
Variational Autoencoders, which we repurpose for popularity-driven
summarization. It uses a clustering interpretation of the quantized space and a
novel extraction algorithm to discover popular opinions among hundreds of
reviews, a significant step towards opinion summarization of practical scope.
In addition, QT enables controllable summarization without further training, by
utilizing properties of the quantized space to extract aspect-specific
summaries. We also make publicly available SPACE, a large-scale evaluation
benchmark for opinion summarizers, comprising general and aspect-specific
summaries for 50 hotels. Experiments demonstrate the promise of our approach,
which is validated by human studies where judges showed clear preference for
our method over competitive baselines.
| [
"cs.CL"
] | cs.CL | Computation and Language | 1,168Computation and Language
|
|
1612.03476 | Kes 79 (G33.6+0.1) is an aspherical thermal composite supernova remnant (SNR)
observed across the electromagnetic spectrum and showing an unusual
highly-structured morphology, in addition to harboring a central compact object
(CCO). Using the CO J=1-0, J=2-1, and J=3-2 data, we provide the first direct
evidence and new morphological evidence to support the physical interaction
between the SNR and the molecular cloud at $V_LSR\sim 105$ km s$^{-1}$. We
revisit the 380 ks XMM-Newton observations and perform a dedicated spatially
resolved X-ray spectroscopic study with careful background subtraction. The
overall X-ray-emitting gas is characterized by an under-ionized ($\tau_c \sim
6\times 10^{11}$ cm^${-3}$) cool ($kT_c \approx 0.20$ keV) plasma with solar
abundances, plus an under-ionized ($\tau_h\sim 8\times 10^{10}$ cm$^{-3}$) hot
($kT_h\approx 0.80$ keV) plasma with elevated Ne, Mg, Si, S and Ar abundances.
Kes 79 appears to have a double-hemisphere morphology viewed along the
symmetric axis. Projection effect can explain the multiple shell structures and
the thermal composite morphology. The X-ray filaments, spatially correlated
with the 24 um IR filaments, are suggested to be due to the SNR shock
interaction with dense gas, while the halo forms from SNR breaking out into a
tenuous medium. The high-velocity, hot ($kT_h\sim 1.4$--1.6 keV) ejecta patch
with high metal abundances, together with the non-uniform metal distribution
across the SNR, indicating an asymmetric SN explosion of Kes 79. We refine the
Sedov age to 4.4--6.7 kyr and the mean shock velocity to 730 km s$^{-1}$. Our
multi-wavelength study suggests a progenitor mass of $\sim 15$--20 solar masses
for the core-collapse explosion that formed Kes 79 and its CCO, PSR J1852+0040.
| [
"astro-ph.HE"
] | astro-ph.HE | High Energy Astrophysical Phenomena | 2,990High Energy Astrophysical Phenomena
|
|
2107.14113 | This article examines neural network-based approximations for the
superhedging price process of a contingent claim in a discrete time market
model. First we prove that the $\alpha$-quantile hedging price converges to the
superhedging price at time $0$ for $\alpha$ tending to $1$, and show that the
$\alpha$-quantile hedging price can be approximated by a neural network-based
price. This provides a neural network-based approximation for the superhedging
price at time $0$ and also the superhedging strategy up to maturity. To obtain
the superhedging price process for $t>0$, by using the Doob decomposition it is
sufficient to determine the process of consumption. We show that it can be
approximated by the essential supremum over a set of neural networks. Finally,
we present numerical results.
| [
"q-fin.MF"
] | q-fin.MF | Mathematical Finance | 4,385Mathematical Finance
|
|
2305.17529 | As the number of recorded meetings increases, it becomes increasingly
important to utilize summarization technology to create useful summaries of
these recordings. However, there is a crucial lack of annotated meeting corpora
for developing this technology, as it can be hard to collect meetings,
especially when the topics discussed are confidential. Furthermore, meeting
summaries written by experienced writers are scarce, making it hard for
abstractive summarizers to produce sensible output without a reliable
reference. This lack of annotated corpora has hindered the development of
meeting summarization technology. In this paper, we present MeetingBank, a new
benchmark dataset of city council meetings over the past decade. MeetingBank is
unique among other meeting corpora due to its divide-and-conquer approach,
which involves dividing professionally written meeting minutes into shorter
passages and aligning them with specific segments of the meeting. This breaks
down the process of summarizing a lengthy meeting into smaller, more manageable
tasks. The dataset provides a new testbed of various meeting summarization
systems and also allows the public to gain insight into how council decisions
are made. We make the collection, including meeting video links, transcripts,
reference summaries, agenda, and other metadata, publicly available to
facilitate the development of better meeting summarization techniques. Our
dataset can be accessed at: https://meetingbank.github.io
| [
"cs.CL"
] | cs.CL | Computation and Language | 1,168Computation and Language
|
|
1304.2959 | We consider the following problem: given that a finite automaton $M$ of $N$
states accepts at least one $k$-power-free (resp., overlap-free) word, what is
the length of the shortest such word accepted? We give upper and lower bounds
which, unfortunately, are widely separated.
| [
"cs.FL",
"cs.DM",
"math.CO"
] | cs.FL | cs.DM | Formal Languages and Automata Theory;Discrete Mathematics;Combinatorics | 2,537Formal Languages and Automata Theory;Discrete Mathematics;Combinatorics
|