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1610.01933 | Chirping frequency patterns have been observed in the electron cyclotron
emission from strongly nonequilibrium plasma confined in a table-top mirror
magnetic trap. Such patterns are typical for the formation of nonlinear phase
space structures in a proximity of the wave-particle resonances of a
kinetically unstable plasma, also known as the "holes and clumps" mechanism.
Our data provides the first experimental evidence for acting of this mechanism
in the electron cyclotron frequency domain.
| [
"physics.plasm-ph"
] | physics.plasm-ph | Plasma Physics | 5,556Plasma Physics
|
|
2207.06707 | The Flux Rope in 3D (FRi3D, Isavnin, 2016), a coronal mass ejection (CME)
model with global three-dimensional (3D) geometry, has been implemented in the
space weather forecasting tool EUHFORIA (Pomoell and Poedts, 2018). By
incorporating this advanced flux rope model in EUHFORIA, we aim to improve the
modelling of CME flank encounters and, most importantly, the magnetic field
predictions at Earth. After using synthetic events to showcase FRi3D's
capabilities of modelling CME flanks, we optimize the model to run robust
simulations of real events and test its predictive capabilities. We perform
observation-based modelling of the halo CME event that erupted on 12 July 2012.
The geometrical input parameters are constrained using the forward modelling
tool included in FRi3D with additional flux rope geometry flexibilities as
compared to the pre-existing models. The magnetic field input parameters are
derived using the differential evolution algorithm to fit FRi3D parameters to
the in situ data at 1 AU. An observation-based approach to constrain the
density of CMEs is adopted, in order to achieve a better estimation of mass
corresponding to the FRi3D geometry. The CME is evolved in EUHFORIA's
heliospheric domain and a comparison of FRi3D's predictive performance with the
previously implemented spheromak CME in EUHFORIA is presented. For this event,
FRi3D improves the modelling of the total magnetic field magnitude and Bz at
Earth by ~30% and ~70%, respectively. Moreover, we compute the expected
geoeffectiveness of the storm at Earth using an empirical Dst model and find
that the FRi3D model improves the predictions of minimum Dst by ~20% as
compared to the spheromak CME model. Finally, we discuss the limitations of the
current implementation of FRi3D in EUHFORIA and propose possible improvements.
| [
"astro-ph.SR",
"astro-ph.EP",
"physics.space-ph"
] | astro-ph.SR | astro-ph.EP | Solar and Stellar Astrophysics;Earth and Planetary Astrophysics;Space Physics | 6,692Solar and Stellar Astrophysics;Earth and Planetary Astrophysics;Space Physics
|
nucl-th/9506027 | The spectral statistics of low--lying states of $fp$ shell nuclei are studied
by performing large shell--model calculations with a realistic nuclear
interaction. For $Ca$ isotopes, we find deviations from the predictions of the
random--matrix theory which suggest that some spherical nuclei are not as
chaotic in nature as the conventional view assumes.
| [
"nucl-th"
] | nucl-th | Nuclear Theory | 4,876Nuclear Theory
|
|
2107.10150 | The evolution of self-gravitating collision-less matter and scalar waves
within the general relativity context is described by Einstein and Vlasov
equations. The sources of Einstein equations are generated by a distribution
function and a scalar field, respectively subject to the Vlasov and wave
equations. We prove in contracting T^2 symmetry case, a local in time existence
of solutions.
| [
"gr-qc"
] | gr-qc | General Relativity and Quantum Cosmology | 2,674General Relativity and Quantum Cosmology
|
|
0710.5420 | MeV particles have been advocated as Dark Matter (DM) candidates in different
contexts. This hypothesis can be tested indirectly by searching for the
Standard Model (SM) products of DM self-annihilations. As the signal from DM
self-annihilations depends on the square of the DM density, we might expect a
sizable flux of annihilation products from our galaxy. Neutrinos are the least
detectable particles in the SM and a null signal in this channel would allow to
set the most conservative bound on the total annihilation cross section. Here,
we show that neutrino detectors with good energy resolution and low energy
thresholds can not only set bounds on the annihilation cross section but
actually test the hypothesis of the possible existence of MeV DM, i.e. test the
values of the cross section required to explain the observed DM density. At
present, the data in the (positron) energy interval [18-82] MeV of the
Super-Kamiokande experiment is already able to put a very stringent bound on
the annihilation cross section for masses between ~15-130 MeV. Future large
experiments, like megaton water-Cherenkov or large scintillator detectors, will
improve the present limits and, if MeV DM exists, would be able to detect it.
| [
"astro-ph",
"hep-ph"
] | astro-ph | hep-ph | Astrophysics;High Energy Physics - Phenomenology | 528Astrophysics;High Energy Physics - Phenomenology
|
1606.04579 | We report the observation of a superconducting state below 8K coexistent with
a spin-glass state caused by atomic disorder in Ce substituted Ca3Rh4Sn13.
Measurements of specific heat, resistivity, and magnetism reveal the existence
of inhomogeneous superconductivity in samples doped with Ce with
superconducting critical temperatures Tc higher than those observed in the
parent compound. For Ca3Rh4Sn13, the negative value of the change in
resistivity with pressure P, correlates well with the calculated decrease in
the density of states at the Fermi energy with P. Based on band structure
calculations performed under pressure, we demonstrate how the change in DOS
would affect Tc of Ca3Rh4Sn13 under negative lattice pressure in samples that
are strongly defected by quenching.
| [
"cond-mat.supr-con",
"cond-mat.str-el"
] | cond-mat.supr-con | cond-mat.str-el | Superconductivity;Strongly Correlated Electrons | 7,102Superconductivity;Strongly Correlated Electrons
|
1503.04262 | We discuss analogues of Newman and Rivlin's formula concerning the ratio of a
partial sum of a power series to its limit function and present a new general
result of this type for entire functions with a certain asymptotic character.
The main tool used in the proof is a Riemann-Hilbert formulation for the
partial sums introduced by Kriecherbauer et al. This new result makes some
progress on verifying a part of the Saff-Varga Width Conjecture concerning the
zero-free regions of these partial sums.
| [
"math.CV"
] | math.CV | Complex Variables | 1,135Complex Variables
|
|
2311.14882 | We study exact matrix completion from partially available data with hidden
connectivity patterns. Exact matrix completion was shown to be possible
recently by Cosse and Demanet in 2021 with Lasserre's relaxation using the
trace of the variable matrix as the objective function with given data
structured in a chain format. In this study, we introduce a structure for the
objective function so that the resulting sum-of-squares (SOS) relaxation, the
dual of Lasserre's SDP relaxation, produces a rank-($N$-1) solution, where $N$
denotes the size of variable matrix in the SOS relaxation. Specifically, the
arrowhead structure is employed for the coefficient matrix of the objective
function. We show that a matrix can be exactly completed through the SOS
relaxation when the connectivity of given data is not explicitly displayed or
follows a chain format. The theoretical exactness is proved using the rank of
the Gram matrix for the SOS relaxation. We also present numerical algorithms
designed to find the coefficient matrix in the SOS relaxation. Numerical
experiments illustrate the validity of the proposed algorithm.
| [
"math.OC"
] | math.OC | Optimization and Control | 5,234Optimization and Control
|
|
2201.08622 | Despite its troubled past, the AOL Query Log continues to be an important
resource to the research community -- particularly for tasks like search
personalisation. When using the query log these ranking experiments, little
attention is usually paid to the document corpus. Recent work typically uses a
corpus containing versions of the documents collected long after the log was
produced. Given that web documents are prone to change over time, we study the
differences present between a version of the corpus containing documents as
they appeared in 2017 (which has been used by several recent works) and a new
version we construct that includes documents close to as they appeared at the
time the query log was produced (2006). We demonstrate that this new version of
the corpus has a far higher coverage of documents present in the original log
(93%) than the 2017 version (55%). Among the overlapping documents, the content
often differs substantially. Given these differences, we re-conduct session
search experiments that originally used the 2017 corpus and find that when
using our corpus for training or evaluation, system performance improves. We
place the results in context by introducing recent adhoc ranking baselines. We
also confirm the navigational nature of the queries in the AOL corpus by
showing that including the URL substantially improves performance across a
variety of models. Our version of the corpus can be easily reconstructed by
other researchers and is included in the ir-datasets package.
| [
"cs.IR"
] | cs.IR | Information Retrieval | 3,577Information Retrieval
|
|
0810.4322 | We consider an incompressible fluid in a three-dimensional pipe, following
the Navier-Stokes system with classical boundary conditions. We are interested
in the following question: is there any optimal shape for the criterion "energy
dissipated by the fluid"? Moreover, is the cylinder the optimal shape? We prove
that there exists an optimal shape in a reasonable class of admissible domains,
but the cylinder is not optimal. For that purpose, we explicit the first order
optimality condition, thanks to adjoint state and we prove that it is
impossible that the adjoint state be a solution of this over-determined system
when the domain is the cylinder. At last, we show some numerical simulations
for that problem.
| [
"math.AP"
] | math.AP | Analysis of PDEs | 205Analysis of PDEs
|
|
2007.15084 | This study introduces database expansion using the Minimum Description Length
(MDL) algorithm to expand the database for better relation extraction.
Different from other previous relation extraction researches, our method
improves system performance by expanding data. The goal of database expansion,
together with a robust deep learning classifier, is to diminish wrong labels
due to the incomplete or not found nature of relation instances in the relation
database (e.g., Freebase). The study uses a deep learning method (Piecewise
Convolutional Neural Network or PCNN) as the base classifier of our proposed
approach: the leveled adversarial attention neural networks (LATTADV-ATT). In
the database expansion process, the semantic entity identification is used to
enlarge new instances using the most similar itemsets of the most common
patterns of the data to get its pairs of entities. About the deep learning
method, the use of attention of selective sentences in PCNN can reduce noisy
sentences. Also, the use of adversarial perturbation training is useful to
improve the robustness of system performance. The performance even further is
improved using a combination of leveled strategy and database expansion. There
are two issues: 1) database expansion method: rule generation by allowing step
sizes on selected strong semantic of most similar itemsets with aims to find
entity pair for generating instances, 2) a better classifier model for relation
extraction. Experimental result has shown that the use of the database
expansion is beneficial. The MDL database expansion helps improvements in all
methods compared to the unexpanded method. The LATTADV-ATT performs as a good
classifier with high precision P@100=0.842 (at no expansion). It is even better
while implemented on the expansion data with P@100=0.891 (at expansion factor
k=7).
| [
"cs.IR"
] | cs.IR | Information Retrieval | 3,577Information Retrieval
|
|
hep-th/0107179 | We examine noncommutative Chern-Simons theory on a bounded spatial domain. We
argue that upon `turning on' the noncommutativity, the edge observables, which
characterized the commutative theory, move into the bulk. We show this to
lowest order in the noncommutativity parameter appearing in the Moyal star
product.
If one includes all orders, the Hamiltonian formulation of the gauge theory
ceases to exist, indicating that the Moyal star product must be modified in the
presence of a boundary. Alternative descriptions are matrix models. We examine
one such model, obtained by a simple truncation of Chern-Simons theory on the
noncommutative plane, and express its observables in terms of Wilson lines.
| [
"hep-th"
] | hep-th | High Energy Physics - Theory | 3,266High Energy Physics - Theory
|
|
1110.1399 | We ask which is the best strategy to reveal uncertainty relations between
comple- mentary observables of a continuous variable system for coarse-grained
measurements. This leads to the derivation of new uncertainty relations for
coarse-grained measurements that are always valid, even for detectors with low
precision. These relations should be particularly relevant in experimental
demonstrations of squeezing in quantum optics, quantum state reconstruction,
and the development of trustworthy entanglement criteria.
| [
"quant-ph"
] | quant-ph | Quantum Physics | 5,985Quantum Physics
|
|
quant-ph/0408048 | A new strategy, using Darboux transformations, of finding self-switching
solutions of $i\dot{\rho} = [H, f({\rho})]$ is introduced. Unlike the previous
ones, working for any f but for Hamiltonians whose spectrum contains at least
three equally spaced eigenvalues, the strategy does not impose any restriction
on the discrete part of the spectrum of H. The strategy is applied to the
Bloch-Maxwell system.
| [
"quant-ph"
] | quant-ph | Quantum Physics | 5,985Quantum Physics
|
|
physics/9804021 | According to an ancient Indian text (c. 1700 BC?), the heavens are 1000 earth
diameters away from the earth. Other texts took the sun to be halfway to the
heavens, so this suggests a distance of the sun about 500 earth diameters from
the earth. The confirmation for this supposition comes from the later theories
(c. 500 AD) from the same region and from Greek ideas that speak of roughly the
same distance. We suggest that this original conception was transformed by the
later Indian and Greek theories in different ways to deal with contradictory
data related to outer planet periods.
| [
"physics.hist-ph",
"physics.ed-ph",
"physics.pop-ph"
] | physics.hist-ph | physics.ed-ph | History and Philosophy of Physics;Physics Education;Popular Physics | 7,267longtail
|
astro-ph/0506668 | We present a statistical analysis of voids in the 2dF galaxy redshift survey
(2dFGRS). In order to detect the voids, we have developed two robust
algorithms. We define voids as non-overlapping maximal spheres empty of halos
or galaxies with mass or luminosity above a given one. We search for voids in
cosmological $N$-Body simulations to test the performance of our void finders.
We obtain and analyze the void statistics for several volume-limited samples
for the North Galactic Strip (NGP) and the South Galactic Strip (SGP)
constructed from the 2dFGRS full data release. We find that the results
obtained from the NGP and the SGP are statistically compatible. From the
results of several statistical tests we conclude that voids are essentially
uncorrelated, with at most a mild anticorrelation and that there is a
dependence of the void number density on redshift at least at the 99.5%
confidence level. We develop a technique to correct the distortion caused by
the fact that we use the redshift as the radial coordinate. We calibrate this
technique with mock catalogues and find that the correction might be of some
relevance to carry out accurate inferences from void statistics. We study the
statistics of the galaxies inside nine nearby voids. We find that galaxies in
voids are not randomly distributed: they form structures like filaments. We
also obtain the galaxy number density profile in voids. This profile follow a
similar but steeper trend to that follow by halos in voids.
| [
"astro-ph"
] | astro-ph | Astrophysics | 463Astrophysics
|
|
1102.2430 | We present results from the analysis of a mosaic of thirteen XMM-Newton
pointings covering the Virgo Cluster from its center northwards out to a radius
r~1.2 Mpc (~4.5 degrees), reaching the virial radius and beyond. This is the
first time that the properties of a modestly sized (M_vir~1.4e14 M_sun, kT~2.3
keV), dynamically young cluster have been studied out to the virial radius. The
density profile of the cluster can be described by a surprisingly shallow
power-law with index 1.21+/-0.12. In the radial range of 0.3r_vir<r<r_vir, the
best fit temperature drops by roughly 60 per cent. Within a radius r<450 kpc,
the entropy profile has an approximate power-law form with index 1.1, as
expected for gravitationally collapsed gas in hydrostatic equilibrium. Beyond
r~450 kpc, however, the temperature and metallicity drop abruptly, and the
entropy profile becomes flatter, staying consistently below the expected value
by a factor of 2-2.5. The most likely explanation for the unusually shallow
density profile and the flattening of entropy at large radius is clumping in
the ICM. Our data provide direct observational evidence that the ICM is
enriched by metals all the way to r_200 to at least Z=0.1 Solar.
| [
"astro-ph.CO",
"astro-ph.HE"
] | astro-ph.CO | astro-ph.HE | Cosmology and Nongalactic Astrophysics;High Energy Astrophysical Phenomena | 1,749Cosmology and Nongalactic Astrophysics;High Energy Astrophysical Phenomena
|
1811.02088 | The infinitesimal generator $A$ of a strongly continuous semigroup on a
Hilbert space is assumed to satisfy that $B_\beta:=A-\beta$ is a sectorial
operator of angle less than $\frac{\pi}{2}$ for some $\beta \geq 0$. If
$B_\beta$ is dissipative in some equivalent scalar product then the
Naimark-Arocena Representation Theorem is applied to obtain a Kre\u{\i}n space
unitary dilation of the semigroup.
| [
"math.FA"
] | math.FA | Functional Analysis | 2,549Functional Analysis
|
|
1101.4599 | We demonstrate existence of non-pairwise interaction forces between vortices
in multicomponent and layered superconducting systems. That is, in contrast to
most common models, the interactions in a group of such vortices is not a
universal superposition of Coulomb or Yukawa forces. Next we consider the
properties of vortex clusters in Semi-Meissner state of type-1.5 two-component
superconductors. We show that under certain condition non-pairwise forces can
contribute to formation of very complex vortex states in type-1.5 regimes.
| [
"cond-mat.supr-con"
] | cond-mat.supr-con | Superconductivity | 7,066Superconductivity
|
|
1206.1687 | Recent mainstream programming languages such as Erlang or Scala have renewed
the interest on the Actor model of concurrency. However, the literature on the
static analysis of actor systems is still lacking of mature formal methods. In
this paper we present a minimal actor calculus that takes as primitive the
basic constructs of Scala's Actors API. More precisely, actors can send
asynchronous messages, process received messages according to a pattern
matching mechanism, and dynamically create new actors, whose scope can be
extruded by passing actor names as message parameters. Drawing inspiration from
the linear types and session type theories developed for process calculi, we
put forward a behavioural type system that addresses the key issues of an actor
calculus. We then study a safety property dealing with the determinism of
finite actor com- munication. More precisely, we show that well typed and
balanced actor systems are (i) deadlock-free and (ii) any message will
eventually be handled by the target actor, and dually no actor will
indefinitely wait for an expected message
| [
"cs.PL"
] | cs.PL | Programming Languages | 5,796Programming Languages
|
|
1709.08412 | We investigate the influence of gradient-enhanced dislocation hardening on
the mechanics of notch-induced failure. The role of geometrically necessary
dislocations (GNDs) in enhancing cracking is assessed by means of a
mechanism-based strain gradient plasticity theory. Both stationary and
propagating cracks from notch-like defects are investigated through the finite
element method. A cohesive zone formulation incorporating monotonic and cyclic
damage contributions is employed to address both loading conditions.
Computations are performed for a very wide range of length scale parameters and
numerous geometries are addressed, covering the main types of notches. Results
reveal a strong influence of the plastic strain gradients in all the scenarios
considered. Transitional combinations of notch angle, radius and length scale
parameter are identified that establish the regimes of GNDs-relevance, laying
the foundations for the rational application of gradient plasticity models in
damage assessment of notched components.
| [
"cond-mat.mtrl-sci"
] | cond-mat.mtrl-sci | Materials Science | 4,287Materials Science
|
|
astro-ph/0701735 | We present a statistical analysis of simultaneous optical and X-ray light
curves, spanning 600 ks, for 814 pre-main-sequence (PMS) stars in the Orion
Nebula Cluster. The aim of this study is to establish the relationship, if any,
between the sites of optical and X-ray variability, and thereby to elucidate
the origins of X-ray production in PMS stars. In a previous paper we showed
that optical and X-ray variability in PMS stars are very rarely
time-correlated. Here, using time-averaged variability indicators to examine
the joint occurrences of optical and X-ray variability, we confirm that the two
forms of variability are not directly causally related. However, a strong and
highly statistically significant correlation is found between optical
variability and X-ray luminosity. As this correlation is found to be
independent of accretion activity, we argue that X-ray production in PMS stars
must instead be intimately connected with the presence and strength of
optically variable, magnetically active surface regions (i.e. spots) on these
stars. Moreover, because X-ray variability and optical variability are rarely
time-correlated, we conclude that the sites of X-ray production are not
exclusively co-spatial with these regions. We argue that solar-analog coronae,
heated by topologically complex fields, can explain these findings.
| [
"astro-ph"
] | astro-ph | Astrophysics | 463Astrophysics
|
|
2310.04593 | This paper shows the usefulness of the Perov contraction theorem, which is a
generalization of the classical Banach contraction theorem, for solving Markov
dynamic programming problems. When the reward function is unbounded, combining
an appropriate weighted supremum norm with the Perov contraction theorem yields
a unique fixed point of the Bellman operator under weaker conditions than
existing approaches. An application to the optimal savings problem shows that
the average growth rate condition derived from the spectral radius of a certain
nonnegative matrix is sufficient and almost necessary for obtaining a solution.
| [
"math.OC",
"econ.TH"
] | math.OC | econ.TH | Optimization and Control;Theoretical Economics | 5,354Optimization and Control;Theoretical Economics
|
2203.07439 | DarkSUSY is a versatile tool for precision calculations of a large variety of
dark matter-related signals, ranging from predictions for the dark matter relic
density to dark matter self-interactions and rates relevant for direct and
indirect detection experiments. In all of these areas significant new code
additions have been made in recent years, since the release of DarkSUSY 6 in
2018, which we summarize in this overview. In particular, DarkSUSY now allows
users to compute the relic density for feebly interacting massive particles via
the freeze-in mechanism, but also offers new routines for freeze-out
calculations in the presence of secluded dark sectors as well as for models
where kinetic equilibrium is not fully established during the freeze-out
process. On the direct detection side, the effect of cosmic-ray upscattering of
dark matter has been fully implemented, leading to a subdominant relativistic
component in the expected dark matter flux at Earth. Finally, updated yields
relevant for indirect searches with gamma rays, neutrinos or charged cosmic
rays have been added; the new default spectra are based on a large number of
Pythia 8 runs, but users can also easily switch between various alternative
spectra. Further code details, including a manual and various concrete example
applications, are provided at www.darksusy.org.
| [
"hep-ph",
"astro-ph.CO"
] | hep-ph | astro-ph.CO | High Energy Physics - Phenomenology;Cosmology and Nongalactic Astrophysics | 3,156High Energy Physics - Phenomenology;Cosmology and Nongalactic Astrophysics
|
1305.0304 | The production of artificial light curves with known statistical and
variability properties is of great importance in astrophysics. Consolidating
the confidence levels during cross-correlation studies, understanding the
artefacts induced by sampling irregularities, establishing detection limits for
future observatories are just some of the applications of simulated data sets.
Currently, the widely used methodology of amplitude and phase randomisation is
able to produce artificial light curves which have a given underlying power
spectral density (PSD) but which are strictly Gaussian distributed. This
restriction is a significant limitation, since the majority of the light curves
e.g. active galactic nuclei, X-ray binaries, gamma-ray bursts show strong
deviations from Gaussianity exhibiting `burst-like' events in their light
curves yielding long-tailed probability distribution functions (PDFs). In this
study we propose a simple method which is able to precisely reproduce light
curves which match both the PSD and the PDF of either an observed light curve
or a theoretical model. The PDF can be representative of either the parent
distribution or the actual distribution of the observed data, depending on the
study to be conducted for a given source. The final artificial light curves
contain all of the statistical and variability properties of the observed
source or theoretical model i.e. same PDF and PSD, respectively. Within the
framework of Reproducible Research, the code, together with the illustrative
example used in this manuscript, are both made publicly available in the form
of an interactive Mathematica notebook.
| [
"astro-ph.IM",
"astro-ph.CO",
"astro-ph.GA",
"astro-ph.HE",
"astro-ph.SR"
] | astro-ph.IM | astro-ph.CO | Instrumentation and Methods for Astrophysics;Cosmology and Nongalactic Astrophysics;Astrophysics of Galaxies;High Energy Astrophysical Phenomena;Solar and Stellar Astrophysics | 3,709Instrumentation and Methods for Astrophysics;Cosmology and Nongalactic Astrophysics;Astrophysics of Galaxies;High Energy Astrophysical Phenomena;Solar and Stellar Astrophysics
|
2206.01860 | This note re-visits the rolling-horizon control approach to the problem of a
Markov decision process (MDP) with infinite-horizon discounted expected reward
criterion. Distinguished from the classical value-iteration approach, we
develop an asynchronous on-line algorithm based on policy iteration integrated
with a multi-policy improvement method of policy switching. A sequence of
monotonically improving solutions to the forecast-horizon sub-MDP is generated
by updating the current solution only at the currently visited state, building
in effect a rolling-horizon control policy for the MDP over infinite horizon.
Feedbacks from "supervisors," if available, can be also incorporated while
updating. We focus on the convergence issue with a relation to the transition
structure of the MDP. Either a global convergence to an optimal
forecast-horizon policy or a local convergence to a "locally-optimal"
fixed-policy in a finite time is achieved by the algorithm depending on the
structure.
| [
"math.OC"
] | math.OC | Optimization and Control | 5,234Optimization and Control
|
|
1710.00548 | We construct a black hole geometry generated by the intersection of $N_c$
color D3- branes and $N_f$ flavor D5-branes along a 2+1 dimensional subspace.
Working in the Veneziano limit in which $N_f$ is large and distributing
homogeneously the D5-branes in the internal space, we calculate the solution of
the equations of motion of supergravity plus sources which includes the
backreaction of the flavor branes. The solution is analytic and dual to a 2+1
dimensional defect in a 3+1 dimensional gauge theory, with $N_f$ massless
hypermultiplets living in the defect. The smeared background we obtain can be
regarded as the holographic realization of a multilayered system. We study the
thermodynamics of the resulting spatially anisotropic geometry and compute the
first and second order transport coefficients for perturbations propagating
along the defect. We find that, in our system, the dynamics of excitations
within a layer can be described by a stack of effective D2-branes.
| [
"hep-th"
] | hep-th | High Energy Physics - Theory | 3,266High Energy Physics - Theory
|
|
1705.04948 | The spin momentum non-orthogonality in 3D topological insulators leads to
modification of the spin texture and brings in an out-of-plane spin
polarization component. Apart from spin texture, the anomalous thermoelectric
properties of these materials are worth studying. In this paper, we have
pointed out that the off resonant light used to irradiate the surface states,
induces a gap, which becomes momentum dependent due to the presence of
non-orthogonal terms in the Hamiltonian. Importantly, to maintain the off
resonant condition of light, the momentum value should satisfy a bound.
Furthermore, the momentum dependent gap causes a topological transition at
higher value of momentum, which is important to analyse the unusual double peak
structure of the Nernst and electrical conductivities.
| [
"cond-mat.mes-hall"
] | cond-mat.mes-hall | Mesoscale and Nanoscale Physics | 4,450Mesoscale and Nanoscale Physics
|
|
2003.05936 | A complete one-loop matching calculation for real singlet scalar extensions
of the Standard Model to the Standard Model effective field theory (SMEFT) of
dimension-six operators is presented. We compare our analytic results obtained
by using Feynman diagrams to the expressions derived in the literature by a
combination of the universal one-loop effective action (UOLEA) approach and
Feynman calculus. After identifying contributions that have been overlooked in
the existing calculations, we find that the pure diagrammatic approach and the
mixed method lead to identical results. We highlight some of the subtleties
involved in computing one-loop matching corrections in SMEFT.
| [
"hep-ph"
] | hep-ph | High Energy Physics - Phenomenology | 3,129High Energy Physics - Phenomenology
|
|
1105.5681 | We propose a new scheme for sharing symmetric key operations among a set of
participants according to a (t,n) threshold access structure. We focus on
anonymity properties of this scheme and show that this scheme provides improved
values of anonymity measures than the existing ones. In particular, the scheme
can provide optimal and equitable participant anonymity when it is based on
balanced perfect hash families.
| [
"cs.CR"
] | cs.CR | Cryptography and Security | 1,782Cryptography and Security
|
|
2104.15017 | We explore a simple semi-analytic model for what happens when an O star (or
cluster of O stars) forms in an isolated filamentary cloud. The model is
characterised by three configuration parameters: the radius of the filament,
R_FIL, the mean density of H_2 in the filament, n_FIL, and the rate at which
the O star emits ionising photons, Ndot_LyC. We show that for a wide range of
these configuration parameters, ionising radiation from the O star rapidly
erodes the filament, and the ionised gas from the filament disperses into the
surroundings. Under these circumstances the distance from the O star to the
ionisation front (IF) is given approximately by L ~ 5.2 pc [R_FIL/0.2pc]^-1/6
[n_FIL/10^4cm^-3]^-1/3 [Ndot_LyC/10^49s^-1]^1/6 [t/Myr]^2/3, and we derive
similar simple power-law expressions for other quantities, for example the rate
at which ionised gas boils off the filament, and the mass of the
shock-compressed layer (SCL) that is swept up behind the IF. We show that a
very small fraction of the ionising radiation is expended locally, and a rather
small amount of molecular gas is ionised and dispersed. We discuss some
features of more realistic models, and the extent to which they might modify or
invalidate the predictions of this idealised model. In particular we show that,
for very large R_FIL and/or large n_FIL and/or low Ndot_LyC, continuing
accretion onto the filament might trap the ionising radiation from the O star,
slowing the erosion of the filament even further.
| [
"astro-ph.GA"
] | astro-ph.GA | Astrophysics of Galaxies | 464Astrophysics of Galaxies
|
|
2311.14909 | Referring Expression Comprehension (REC) aims to localize an image region of
a given object described by a natural-language expression. While promising
performance has been demonstrated, existing REC algorithms make a strong
assumption that training data feeding into a model are given upfront, which
degrades its practicality for real-world scenarios. In this paper, we propose
Continual Referring Expression Comprehension (CREC), a new setting for REC,
where a model is learning on a stream of incoming tasks. In order to
continuously improve the model on sequential tasks without forgetting prior
learned knowledge and without repeatedly re-training from a scratch, we propose
an effective baseline method named Dual Modular Memorization (DMM), which
alleviates the problem of catastrophic forgetting by two memorization modules:
Implicit-Memory and Explicit-Memory. Specifically, the former module aims to
constrain drastic changes to important parameters learned on old tasks when
learning a new task; while the latter module maintains a buffer pool to
dynamically select and store representative samples of each seen task for
future rehearsal. We create three benchmarks for the new CREC setting, by
respectively re-splitting three widely-used REC datasets RefCOCO, RefCOCO+ and
RefCOCOg into sequential tasks. Extensive experiments on the constructed
benchmarks demonstrate that our DMM method significantly outperforms other
alternatives, based on two popular REC backbones. We make the source code and
benchmarks publicly available to foster future progress in this field:
https://github.com/zackschen/DMM.
| [
"cs.CV"
] | cs.CV | Computer Vision and Pattern Recognition | 1,498Computer Vision and Pattern Recognition
|
|
1709.06742 | Based on $448.1 \times 10^6$ $\psi(3686)$ events collected with the BESIII
detector, the decays $\psi(3686)\to\gamma\chi_{cJ}, \chi_{cJ} \to
\gamma\gamma~(J=0, 1, 2)$ are studied. The decay branching fractions of
$\chi_{c0,c2} \to \gamma\gamma$ are measured to be
$\mathcal{B}(\chi_{c0}\to\gamma\gamma) = (1.93 \pm 0.08 \pm 0.05 \pm
0.05)\times 10^{-4}$ and $\mathcal{B}(\chi_{c2}\to\gamma\gamma) = (3.10 \pm
0.09 \pm 0.07 \pm 0.11)\times 10^{-4} $, which correspond to two-photon decay
widths of $\Gamma_{\gamma\gamma}(\chi_{c0}) = 2.03 \pm 0.08 \pm 0.06 \pm 0.13
~\rm{keV}$ and $\Gamma_{\gamma\gamma}(\chi_{c2}) = 0.60 \pm 0.02 \pm 0.01 \pm
0.04 ~\rm{keV}$ with a ratio of
$\mathcal{R}=\Gamma_{\gamma\gamma}(\chi_{c2})/\Gamma_{\gamma\gamma}(\chi_{c0})=
0.295 \pm 0.014 \pm 0.007 \pm 0.027$, where the uncertainties are statistical,
systematic and associated with the uncertainties of
$\mathcal{B}(\psi(3686)\to\gamma\chi_{c0,c2})$ and the total widths
$\Gamma(\chi_{c0,c2})$, respectively. For the forbidden decay of
$\chi_{c1}\to\gamma\gamma$, no signal is observed, and an upper limit on the
two-photon width is obtained to be $\Gamma_{\gamma\gamma}(\chi_{c1})<5.3
~\rm{eV}$ at the 90\% confidence level. The ratio of the two-photon widths
between helicity-zero and helicity-two components in the decay
$\chi_{c2}\to\gamma\gamma$ is also measured to be $f_{0/2} =
\Gamma^{\lambda=0}_{\gamma\gamma}(\chi_{c2})/\Gamma^{\lambda=2}_{\gamma\gamma}(\chi_{c2})
= (0.0 \pm 0.6 \pm 1.2)\times 10^{-2}$, where the uncertainties are statistical
and systematic, respectively.
| [
"hep-ex"
] | hep-ex | High Energy Physics - Experiment | 3,059High Energy Physics - Experiment
|
|
0704.0232 | In this expository article we review recent advances in our understanding of
the combinatorial and algebraic structure of perturbation theory in terms of
Feynman graphs, and Dyson-Schwinger equations. Starting from Lie and Hopf
algebras of Feynman graphs, perturbative renormalization is rephrased
algebraically. The Hochschild cohomology of these Hopf algebras leads the way
to Slavnov-Taylor identities and Dyson-Schwinger equations. We discuss recent
progress in solving simple Dyson-Schwinger equations in the high energy sector
using the algebraic machinery. Finally there is a short account on a relation
to algebraic geometry and number theory: understanding Feynman integrals as
periods of mixed (Tate) motives.
| [
"hep-th"
] | hep-th | High Energy Physics - Theory | 3,266High Energy Physics - Theory
|
|
2305.19664 | To increase the generalization capability of VQA systems, many recent studies
have tried to de-bias spurious language or vision associations that shortcut
the question or image to the answer. Despite these efforts, the literature
fails to address the confounding effect of vision and language simultaneously.
As a result, when they reduce bias learned from one modality, they usually
increase bias from the other. In this paper, we first model a confounding
effect that causes language and vision bias simultaneously, then propose a
counterfactual inference to remove the influence of this effect. The model
trained in this strategy can concurrently and efficiently reduce vision and
language bias. To the best of our knowledge, this is the first work to reduce
biases resulting from confounding effects of vision and language in VQA,
leveraging causal explain-away relations. We accompany our method with an
explain-away strategy, pushing the accuracy of the questions with numerical
answers results compared to existing methods that have been an open problem.
The proposed method outperforms the state-of-the-art methods in VQA-CP v2
datasets.
| [
"cs.CV",
"cs.CL",
"cs.MM"
] | cs.CV | cs.CL | Computer Vision and Pattern Recognition;Computation and Language;Multimedia | 1,544Computer Vision and Pattern Recognition;Computation and Language;Multimedia
|
1804.04843 | We present the analysis of the impedance spectra for a binary electrolyte
confined between blocking electrodes with dielectric layers. An expression for
the impedance is derived from Poisson-Nernst-Planck equations in the linear
approximation taking into account the voltage drop on the dielectric layer. The
analysis shows, that characteristic features of the frequency dependence of the
impedance are determined by the ratio of the Debay length and the effective
thickness of the dielectric layer. The impact of the dielectric layer is
especially strong in the case of high concentrated electrolytes, where the
Debay length is small and thus comparable to the effective thickness of the
dielectric layer. To verify the model, measurements of the impedance spectra
and transient currents in a liquid crystal 4-n-pentyl-4'-cyanobiphenyl (5CB)
confined between polymer-coated electrodes in cells of different thicknesses
are performed. The estimates for the diffusion coefficient and ion
concentration in 5CB obtained from the analysis of the impedance spectra and
the transient currents are consistent and agree with previously reported data.
We demonstrate that calculations of the ion parameters from the impedance
spectra without taking into account the dielectric layer contribution lead in
most cases to incorrect results. Application of the model to analyze violations
of the low-frequency impedance scaling and contradictions in the estimates of
the ion parameters recently found in some ionic electrolytes are discussed.
| [
"cond-mat.soft"
] | cond-mat.soft | Soft Condensed Matter | 6,537Soft Condensed Matter
|
|
0705.2812 | We establish a correlation between the internal stress in InN epilayers and
their optical properties such as the measured absorption band edge and
photoluminescence emission wavelength. By a careful evaluation of the lattice
constants of InN epilayers grown on c-plane sapphire substrates under various
conditions by metalorganic vapor phase epitaxy we find that the films are under
primarily hydrostatic stress. This results in a shift in the band edge to
higher energy. The effect is significant, and may be responsible for some of
the variations in InN bandgap reported in the literature.
| [
"cond-mat.mtrl-sci"
] | cond-mat.mtrl-sci | Materials Science | 4,287Materials Science
|
|
2110.13334 | Among the fundamental and most challenging problems of laboratory, space, and
astrophysical plasma physics is to understand the relaxation processes of
nearly collisionless plasmas toward quasi-stationary states; and the resultant
states of electromagnetic plasma turbulence. Recently, it has been argued that
solar wind plasma $\beta$ and temperature anisotropy observations may be
regulated by kinetic instabilities such as the ion-cyclotron, mirror,
electron-cyclotron, and firehose instabilities; and that magnetic fluctuation
observations are consistent with the predictions of the Fluctuation-Dissipation
theorem, even far below the kinetic instability thresholds. Here, using in-situ
magnetic field and plasma measurements by the THEMIS satellite mission, we show
that such regulation seems to occur also in the Earth's magnetotail plasma
sheet at the ion and electron scales. Regardless of the clear differences
between the solar wind and the magnetotail environments, our results indicate
that spontaneous fluctuations and their collisionless regulation are
fundamental features of space and astrophysical plasmas, thereby suggesting the
processes is universal.
| [
"physics.space-ph",
"astro-ph.EP",
"physics.plasm-ph"
] | physics.space-ph | astro-ph.EP | Space Physics;Earth and Planetary Astrophysics;Plasma Physics | 6,769Space Physics;Earth and Planetary Astrophysics;Plasma Physics
|
2003.01062 | We present ProxEmo, a novel end-to-end emotion prediction algorithm for
socially aware robot navigation among pedestrians. Our approach predicts the
perceived emotions of a pedestrian from walking gaits, which is then used for
emotion-guided navigation taking into account social and proxemic constraints.
To classify emotions, we propose a multi-view skeleton graph convolution-based
model that works on a commodity camera mounted onto a moving robot. Our emotion
recognition is integrated into a mapless navigation scheme and makes no
assumptions about the environment of pedestrian motion. It achieves a mean
average emotion prediction precision of 82.47% on the Emotion-Gait benchmark
dataset. We outperform current state-of-art algorithms for emotion recognition
from 3D gaits. We highlight its benefits in terms of navigation in indoor
scenes using a Clearpath Jackal robot.
| [
"cs.RO",
"cs.AI",
"cs.HC"
] | cs.RO | cs.AI | Robotics;Artificial Intelligence;Human-Computer Interaction | 6,338Robotics;Artificial Intelligence;Human-Computer Interaction
|
hep-th/9410224 | We present a general argument for the construction of BRST charges of the
`non-critical' $\W_{2,4}$, $\W_{2,5}$, $\W_{2,6}$, and $\W_{2,8}$ strings. This
evidences the existence of BRST charges for a kind of soft-type algebras which
can be constructed from two copies of quantum $\W_{2,s}$ algebras,
(s=3,4,5,6,8).
| [
"hep-th"
] | hep-th | High Energy Physics - Theory | 3,266High Energy Physics - Theory
|
|
1410.3816 | We prove that complex networks of interactions have the capacity to regulate
and buffer unpredictable fluctuations in production events. We show that
non-bursty network-driven activation dynamics can effectively regulate the
level of burstiness in the production of nodes, which can be enhanced or
reduced. Burstiness can be induced even when the endogenous inter-event time
distribution of nodes' production is non-bursty. We found that hubs tend to be
less controllable than low degree nodes, which are more susceptible to the
networked regulatory effects. Our results have important implications for the
analysis and engineering of bursty activity in a range of systems, from
telecommunication networks to transcription and translation of genes into
proteins in cells.
| [
"physics.soc-ph"
] | physics.soc-ph | Physics and Society | 5,463Physics and Society
|
|
1002.3924 | The standard phenomenological Hamiltonian of a small superconducting
Josephson junction in the charge regime (Cooper Pair Box) produces a model of
the effective charge qubit with possible applications to quantum information
processing. In this note a new model based on the BCS Hamiltonian with
individual tunneling yields an effective multi-level picture with a highly
degenerated level placed between the ground state and the excited state. Unlike
in the standard approach, the excited Cooper pairs play here an important role.
For such a system coupled to a zero temperature bath the additional levels act
as a probability sink. In contrast to the standard large-spin model the
coupling to phonons can be an effective source of dissipation. This model
provides also alternative explanations of various effects observed in
experiments and sheds new light on the issue of Josephson junctions as
macroscopic quantum systems.
| [
"quant-ph",
"cond-mat.supr-con"
] | quant-ph | cond-mat.supr-con | Quantum Physics;Superconductivity | 6,210Quantum Physics;Superconductivity
|
1401.8049 | We consider the initial/boundary value problem for a diffusion equation
involving multiple time-fractional derivatives on a bounded convex polyhedral
domain. We analyze a space semidiscrete scheme based on the standard Galerkin
finite element method using continuous piecewise linear functions. Nearly
optimal error estimates for both cases of initial data and inhomogeneous term
are derived, which cover both smooth and nonsmooth data. Further we develop a
fully discrete scheme based on a finite difference discretization of the
time-fractional derivatives, and discuss its stability and error estimate.
Extensive numerical experiments for one and two-dimension problems confirm the
convergence rates of the theoretical results.
| [
"math.NA"
] | math.NA | Numerical Analysis | 5,002Numerical Analysis
|
|
q-alg/9607031 | On the level-1 Fock space modules of the algebra $U_q(\hat{sl_n})$ we define
a level-0 action $U_0$ of the $U_q(\hat{sl_n})$, and an action of an abelian
algebra of conserved Hamiltonians commuting with the $U_0$. An irreducible
decomposition of the Fock space with respect to the level-0 action is derived
by constructing a base of the Fock space in terms of the Non-symmetric
Macdonald Polynomials.
| [
"q-alg",
"math.QA"
] | q-alg | math.QA | Quantum Algebra;Quantum Algebra | 5,909Quantum Algebra;Quantum Algebra
|
1705.09019 | Magnetic skyrmions are topologically-protected spin textures with attractive
properties suitable for high-density and low-power spintronic device
applications. Much effort has been dedicated to understanding the dynamical
behaviours of the magnetic skyrmions. However, experimental observation of the
ultrafast dynamics of this chiral magnetic texture in real space, which is the
hallmark of its quasiparticle nature, has so far remained elusive. Here, we
report nanosecond-dynamics of a 100 nm-size magnetic skyrmion during a current
pulse application, using a time-resolved pump-probe soft X-ray imaging
technique. We demonstrate that distinct dynamic excitation states of magnetic
skyrmions, triggered by current-induced spin-orbit torques, can be reliably
tuned by changing the magnitude of spin-orbit torques. Our findings show that
the dynamics of magnetic skyrmions can be controlled by the spin-orbit torque
on the nanosecond time scale, which points to exciting opportunities for
ultrafast and novel skyrmionic applications in the future.
| [
"cond-mat.mtrl-sci",
"cond-mat.mes-hall"
] | cond-mat.mtrl-sci | cond-mat.mes-hall | Materials Science;Mesoscale and Nanoscale Physics | 4,330Materials Science;Mesoscale and Nanoscale Physics
|
1405.4068 | We study the topological phases in spin-orbit coupled dipolar bosons in a
one-dimensional optical lattice. The magnetic dipolar interactions between
atoms give rise to the inter-site interactions. In the Mott-insulating regime,
this system can be described by the quantum XYZ spin model with the
Dzyaloshinskii-Moriya interactions in a transverse field. We focus on
investigating the effect of dipolar interactions on the topological phase. The
topological phase can be shown when spin-orbit coupling incorporates with the
repulsive dipolar interaction. We find that the dipolar interaction can broaden
the range of parameters of spin-orbit coupling and transverse field for
exhibiting the topological phase. The sum of spin correlations between the two
nearest neighbouring atoms can be used to indicate the topological phase. This
may be useful for detecting topological phases in experiments.
| [
"cond-mat.quant-gas",
"cond-mat.stat-mech"
] | cond-mat.quant-gas | cond-mat.stat-mech | Quantum Gases;Statistical Mechanics | 5,967Quantum Gases;Statistical Mechanics
|
1106.1699 | The small dispersion limit of the focusing nonlinear Schro\"odinger equation
(NLS) exhibits a rich structure of sharply separated regions exhibiting
disparate rapid oscillations at microscopic scales. The non self-adjoint
scattering problem and ill-posed limiting Whitham equa- tions associated to
focusing NLS make rigorous asymptotic results difficult. Previous studies
[KMM03, TVZ04, TVZ06] have focused on special classes of analytic initial data
for which the limiting elliptic Whitham equations are well-posed. In this paper
we consider another exactly solvable family of initial data, the family of
square barriers, $\psi_0(x) = q \chi_[-L,L]$ for real amplitudes q. Using
Riemann-Hilbert techniques we obtain rigorous pointwise asymptotics for the
semiclas-sical limit of focusing NLS globally in space and up to an O(1)
maximal time. In particular, we show that the discontinuities in our initial
data regularize by the immediate generation of genus one oscillations emitted
into the support of the initial data. To the best of our knowledge, this is the
first case in which the genus structure of the semiclassical asymptotics for
fNLS have been calculated for non-analytic initial data.
| [
"math.AP",
"nlin.SI"
] | math.AP | nlin.SI | Analysis of PDEs;Exactly Solvable and Integrable Systems | 238Analysis of PDEs;Exactly Solvable and Integrable Systems
|
cond-mat/0611642 | Optical second-harmonic-generation(SHG) observations and precise X-ray
diffraction experiments have been performed on quantum paraelectrics KTaO3
(KTO) and relaxor K(1-x)LixTaO3 with x=3% (KLT-3) and 7% (KLT-7). It is found
in KLT-3 and KLT-7 that a pretransitional region exists between two
characteristic temperatures Td and Tp (<Td). The average symmetry of the region
is tetragonal with a weak lattice-deformation but non-polar in average. The
temperature interval between Td and Tp is consistent with the interval on which
neutron diffuse scatterings have been previously reported. These facts strongly
suggest that polar micro-regions (PMRs) nucleate around Td and grow toward Tp.
Below Tp, a larger deformation and a field-induced SH intensity start to
develop, while no significant SHG appear in zero-field cooling process. The
temperature dependence of the SH intensity below Tp coincides well with that of
the tetragonality determined from the lattice deformation. The
Landau-Devonshire phenomenological approach suggests that the ferroelectric
phase transition at Tp is of first order and that it approaches the second
order transition with the decrease of Li concentration. A marked increase of
neutron diffraction intensities below Tp indicates that PMRs are transformed to
ferroelectric micro-domains at Tp, and the micro-domains change to macroscopic
ones under the electric field below Tp.
| [
"cond-mat.mtrl-sci"
] | cond-mat.mtrl-sci | Materials Science | 4,287Materials Science
|
|
1704.01513 | While modern parallel computing systems provide high performance resources,
utilizing them to the highest extent requires advanced programming expertise.
Programming for parallel computing systems is much more difficult than
programming for sequential systems. OpenMP is an extension of C++ programming
language that enables to express parallelism using compiler directives. While
OpenMP alleviates parallel programming by reducing the lines of code that the
programmer needs to write, deciding how and when to use these compiler
directives is up to the programmer. Novice programmers may make mistakes that
may lead to performance degradation or unexpected program behavior. Cognitive
computing has shown impressive results in various domains, such as health or
marketing. In this paper, we describe the use of IBM Watson cognitive system
for education of novice parallel programmers. Using the dialogue service of the
IBM Watson we have developed a solution that assists the programmer in avoiding
common OpenMP mistakes. To evaluate our approach we have conducted a survey
with a number of novice parallel programmers at the Linnaeus University, and
obtained encouraging results with respect to usefulness of our approach.
| [
"cs.PL"
] | cs.PL | Programming Languages | 5,796Programming Languages
|
|
1908.07206 | The Next-to Minimal Supersymmetric Standard Model (NMSSM) with a Type-I
seesaw mechanism extends the NMSSM by three generations of right-handed
neutrino fields to generate neutrino mass. As a byproduct it renders the
lightest sneutrino as a viable DM candidate. Due to the gauge singlet nature of
the DM, its scattering with nucleon is suppressed in most cases to coincide
spontaneously with the latest XENON-1T results. Consequently, broad parameter
spaces in the Higgs sector, especially a light Higgsino mass, are resurrected
as experimentally allowed, which makes the theory well suited to explain the
long standing $b \bar{b}$ excess at LEP-II and the continuously observed
$\gamma \gamma$ excess by CMS collaboration. We show by both analytic formulas
and numerical results that the theory can naturally predict the central values
of the excesses in its broad parameter space, and the explanations are
consistent with the Higgs data of the discovered Higgs boson, $B-$physics and
DM physics measurements, the electroweak precision data as well as the LHC
search for sparticles. Part of the explanations may be tested by future DM
experiments and the SUSY search at the LHC.
| [
"hep-ph"
] | hep-ph | High Energy Physics - Phenomenology | 3,129High Energy Physics - Phenomenology
|
|
math/0608203 | The aim of this brief note for the volume in honor of S. S. Chern is to give
a construction for $p$-torsion line bundles in characteristic $p>0$ which plays
a similar r\^ole as the standard connection on an $n$-torsion line bundle in
characteristic 0.
| [
"math.AG"
] | math.AG | Algebraic Geometry | 47Algebraic Geometry
|
|
1101.1267 | The eruption of V4332 Sgr was observed in 1994. During the outburst, the
object became extremely red, so it is considered as belonging to luminous red
transients of the V838 Mon type. It has recently been suggested that the
central object in V4332 Sgr is now hidden in a dusty disc and that the
photospheric spectrum of this object observed in the optical results from
scattering the central star radiation on dust grains in the disc. One expects
significant polarization of the spectrum in this case. We investigate this
prediction. We present and analyse polarimetric observations of V4332 Sgr in
the V and R photometric bands done with the NOT telescope. The optical light of
V4332 Sgr is linearly polarized with a degree of ~26% in the V band and ~11% in
R. Discussion of the observed polarization leads us to conclude that the
photospheric spectrum observed in V4332 Sgr is probably produced by dust
scattering not only in the disc but also in the outflow from the object seen in
the emission features.
| [
"astro-ph.SR"
] | astro-ph.SR | Solar and Stellar Astrophysics | 6,668Solar and Stellar Astrophysics
|
|
0811.0549 | We consider conservation laws with source terms in a bounded domain with
Dirichlet boundary conditions. We first prove the existence of a strong trace
at the boundary in order to provide a simple formulation of the entropy
boundary condition. Equipped with this formulation, we go on to establish the
well-posedness of entropy solutions to the initial-boundary value problem. The
proof utilizes the kinetic formulation and the compensated compactness method.
Finally, we make use of these results to demonstrate the well-posedness in a
class of discontinuous solutions to the initial-boundary value problem for the
Degasperis-Procesi shallow water equation, which is a third order nonlinear
dispersive equation that can be rewritten in the form of a nonlinear
conservation law with a nonlocal source term.
| [
"math.AP"
] | math.AP | Analysis of PDEs | 205Analysis of PDEs
|
|
1606.04358 | Recently, it has been shown by Lobo, Parsaei and Riazi (LPR) that phantom
energy with $\omega =p_{r}/\rho <-1$ could support phantom wormholes. Several
classes of such solutions have been derived by them. While the inner spacetime
is represented by asymptotically flat phantom wormhole that have repulsive
gravity, it is most likely to be unstable to perturbations. Hence, we consider
a situation, where a phantom wormhole is somehow trapped inside a Schwarzschild
sphere across a thin shell. Applying the method developed by Garcia, Lobo and
Visser (GLV), we shall exemplify that the shell can possess zones of stability
depending on certain constraints. It turns out that zones corresponding to
"force" constraint are more restrictive than those from the "mass" constraint.
We shall also enumerate the interior energy content by using the gravitational
energy integral proposed by Lynden-Bell, Katz and Bi% \v{c}\'ak. It turns out
that, even though the interior mass is positive, the integral implies repulsive
energy. This is consistent with the phantom nature of interior matter.
| [
"gr-qc"
] | gr-qc | General Relativity and Quantum Cosmology | 2,674General Relativity and Quantum Cosmology
|
|
hep-ph/9702250 | We emphasize the role that anomalous power-law scaling of 4-fermion
operators, occurring in the presence of new strong interactions, could have in
the generation of quark and lepton masses.
| [
"hep-ph"
] | hep-ph | High Energy Physics - Phenomenology | 3,129High Energy Physics - Phenomenology
|
|
2301.01588 | Historically, the analysis of stimulus-dependent time-frequency patterns has
been the cornerstone of most electroencephalography (EEG) studies. The abnormal
oscillations in high-frequency waves associated with psychotic disorders during
sensory and cognitive tasks have been studied many times. However, any
significant dissimilarity in the resting-state low-frequency bands is yet to be
established. Spectral analysis of the alpha and delta band waves shows the
effectiveness of stimulus-independent EEG in identifying the abnormal activity
patterns of pathological brains. A generalized model incorporating multiple
frequency bands should be more efficient in associating potential EEG
biomarkers with First-Episode Psychosis (FEP), leading to an accurate
diagnosis. We explore multiple machine-learning methods, including
random-forest, support vector machine, and Gaussian Process Classifier (GPC),
to demonstrate the practicality of resting-state Power Spectral Density (PSD)
to distinguish patients of FEP from healthy controls. A comprehensive
discussion of our preprocessing methods for PSD analysis and a detailed
comparison of different models are included in this paper. The GPC model
outperforms the other models with a specificity of 95.78% to show that PSD can
be used as an effective feature extraction technique for analyzing and
classifying resting-state EEG signals of psychiatric disorders.
| [
"q-bio.NC",
"cs.LG",
"eess.SP"
] | q-bio.NC | cs.LG | Neurons and Cognition;Machine Learning;Signal Processing | 4,835Neurons and Cognition;Machine Learning;Signal Processing
|
hep-ph/0106039 | Recent progress in understanding the physics of B mesons and of CP violation,
as presented to this Workshop, is put in historical perspective and summarized.
| [
"hep-ph"
] | hep-ph | High Energy Physics - Phenomenology | 3,129High Energy Physics - Phenomenology
|
|
1408.3944 | In the field of gestural action recognition, many studies have focused on
dimensionality reduction along the spatial axis, to reduce both the variability
of gestural sequences expressed in the reduced space, and the computational
complexity of their processing. It is noticeable that very few of these methods
have explicitly addressed the dimensionality reduction along the time axis.
This is however a major issue with regard to the use of elastic distances
characterized by a quadratic complexity. To partially fill this apparent gap,
we present in this paper an approach based on temporal down-sampling associated
to elastic kernel machine learning. We experimentally show, on two data sets
that are widely referenced in the domain of human gesture recognition, and very
different in terms of quality of motion capture, that it is possible to
significantly reduce the number of skeleton frames while maintaining a good
recognition rate. The method proves to give satisfactory results at a level
currently reached by state-of-the-art methods on these data sets. The
computational complexity reduction makes this approach eligible for real-time
applications.
| [
"cs.LG",
"cs.HC"
] | cs.LG | cs.HC | Machine Learning;Human-Computer Interaction | 4,148Machine Learning;Human-Computer Interaction
|
2308.05986 | Given a set of pre-trained models, how can we quickly and accurately find the
most useful pre-trained model for a downstream task? Transferability
measurement is to quantify how transferable is a pre-trained model learned on a
source task to a target task. It is used for quickly ranking pre-trained models
for a given task and thus becomes a crucial step for transfer learning.
Existing methods measure transferability as the discrimination ability of a
source model for a target data before transfer learning, which cannot
accurately estimate the fine-tuning performance. Some of them restrict the
application of transferability measurement in selecting the best supervised
pre-trained models that have classifiers. It is important to have a general
method for measuring transferability that can be applied in a variety of
situations, such as selecting the best self-supervised pre-trained models that
do not have classifiers, and selecting the best transferring layer for a target
task. In this work, we propose TMI (TRANSFERABILITY MEASUREMENT WITH
INTRA-CLASS FEATURE VARIANCE), a fast and accurate algorithm to measure
transferability. We view transferability as the generalization of a pre-trained
model on a target task by measuring intra-class feature variance. Intra-class
variance evaluates the adaptability of the model to a new task, which measures
how transferable the model is. Compared to previous studies that estimate how
discriminative the models are, intra-class variance is more accurate than those
as it does not require an optimal feature extractor and classifier. Extensive
experiments on real-world datasets show that TMI outperforms competitors for
selecting the top-5 best models, and exhibits consistently better correlation
in 13 out of 17 cases.
| [
"cs.LG"
] | cs.LG | Machine Learning | 3,882Machine Learning
|
|
gr-qc/0602001 | It has previously been shown that the Einstein equation can be derived from
the requirement that the Clausius relation dS = dQ/T hold for all local
acceleration horizons through each spacetime point, where dS is one quarter the
horizon area change in Planck units, and dQ and T are the energy flux across
the horizon and Unruh temperature seen by an accelerating observer just inside
the horizon. Here we show that a curvature correction to the entropy that is
polynomial in the Ricci scalar requires a non-equilibrium treatment. The
corresponding field equation is derived from the entropy balance relation dS
=dQ/T+dS_i, where dS_i is a bulk viscosity entropy production term that we
determine by imposing energy-momentum conservation. Entropy production can also
be included in pure Einstein theory by allowing for shear viscosity of the
horizon.
| [
"gr-qc",
"cond-mat.stat-mech",
"hep-th",
"quant-ph"
] | gr-qc | cond-mat.stat-mech | General Relativity and Quantum Cosmology;Statistical Mechanics;High Energy Physics - Theory;Quantum Physics | 2,780General Relativity and Quantum Cosmology;Statistical Mechanics;High Energy Physics - Theory;Quantum Physics
|
1908.05985 | We present a high-resolution in-beam $\gamma$-ray spectroscopy study of
excited states in the mirror nuclei $^{55}$Co and $^{55}$Ni following
one-nucleon knockout from a projectile beam of $^{56}$Ni. The newly determined
partial cross sections and the $\gamma$-decay properties of excited states
provide a test of state-of-the-art nuclear structure models and probe mirror
symmetry in unique ways. A mirror asymmetry for the partial cross sections
leading to the two lowest $3/2^-$ states in the $A = 55$ mirror pair was
identified as well as a significant difference in the $E1$ decays from the
$1/2^+_1$ state to the same two $3/2^-$ states. The mirror asymmetry in the
partial cross sections cannot be reconciled with the present shell-model
picture or small mixing introduced in a two-state model. The observed mirror
asymmetry in the $E1$ decay pattern, however, points at stronger mixing between
the two lowest $3/2^-$ states in $^{55}$Co than in its mirror $^{55}$Ni.
| [
"nucl-ex",
"nucl-th"
] | nucl-ex | nucl-th | Nuclear Experiment;Nuclear Theory | 4,873Nuclear Experiment;Nuclear Theory
|
2306.00902 | We report on our monitoring of the strong-field magnetar-like pulsar PSR
J1846-0258 with the Neutron Star Interior Composition Explorer (NICER) and the
timing and spectral evolution during its outburst in August 2020.
Phase-coherent timing solutions were maintained from March 2017 through
November 2021, including a coherent solution throughout the outburst. We
detected a large spin-up glitch of magnitude \Delta\nu/\nu = 3 X 10^{-6} at the
start of the outburst and observed an increase in pulsed flux that reached a
factor of more than 10 times the quiescent level, a behavior similar to that of
the 2006 outburst. Our monitoring observations in June and July 2020 indicate
that the flux was rising prior to the SWIFT announcement of the outburst on
August 1, 2020. We also observed several sharp rises in the pulsed flux
following the outburst and the flux reached quiescent level by November 2020.
The pulse profile was observed to change shape during the outburst, returning
to the pre-outburst shape by 2021. Spectral analysis of the pulsed emission of
NICER data shows that the flux increases result entirely from a new black body
component that gradually fades away while the power-law remains nearly constant
at its quiescent level throughout the outburst. Joint spectral analysis of
NICER and simultaneous NuSTAR data confirms this picture. We discuss the
interpretation of the magnetar-like outburst and origin of the transient
thermal component in the context of both a pulsar-like and a magnetar-like
model.
| [
"astro-ph.HE"
] | astro-ph.HE | High Energy Astrophysical Phenomena | 2,990High Energy Astrophysical Phenomena
|
|
2306.02776 | The misuse of real photographs with conflicting image captions in news items
is an example of the out-of-context (OOC) misuse of media. In order to detect
OOC media, individuals must determine the accuracy of the statement and
evaluate whether the triplet (~\textit{i.e.}, the image and two captions)
relates to the same event. This paper presents a novel learnable approach for
detecting OOC media in ICME'23 Grand Challenge on Detecting Cheapfakes. The
proposed method is based on the COSMOS structure, which assesses the coherence
between an image and captions, as well as between two captions. We enhance the
baseline algorithm by incorporating a Large Language Model (LLM), GPT3.5, as a
feature extractor. Specifically, we propose an innovative approach to feature
extraction utilizing prompt engineering to develop a robust and reliable
feature extractor with GPT3.5 model. The proposed method captures the
correlation between two captions and effectively integrates this module into
the COSMOS baseline model, which allows for a deeper understanding of the
relationship between captions. By incorporating this module, we demonstrate the
potential for significant improvements in cheap-fakes detection performance.
The proposed methodology holds promising implications for various applications
such as natural language processing, image captioning, and text-to-image
synthesis. Docker for submission is available at
https://hub.docker.com/repository/docker/mulns/ acmmmcheapfakes.
| [
"cs.CV"
] | cs.CV | Computer Vision and Pattern Recognition | 1,498Computer Vision and Pattern Recognition
|
|
hep-th/0204153 | We perform a systematic string computation of the masses of anomalous U(1)
gauge bosons in four-dimensional orientifold vacua, and we study their
localization properties in the internal (compactified) space. We find that N=1
supersymmetric sectors yield four-dimensional contributions, localized in the
whole six-dimensional internal space, while N=2 sectors give contributions
localized in four internal dimensions. As a result, the U(1) gauge fields can
be much lighter than the string scale, so that when the latter is at the TeV,
they can mediate new non-universal repulsive forces at submillimeter distances
much stronger than gravity. We also point out that even U(1)s which are free of
four-dimensional anomalies may acquire non-zero masses as a consequence of
six-dimensional anomalies.
| [
"hep-th",
"hep-ph"
] | hep-th | hep-ph | High Energy Physics - Theory;High Energy Physics - Phenomenology | 3,348High Energy Physics - Theory;High Energy Physics - Phenomenology
|
1708.02404 | Prethermalization refers to the relaxation to a quasi-stationary state before
reaching thermal equilibrium. Recently, it is found that not only local
conserved quantities but also entanglement plays a key role in a special type
of prethermalization, called entanglement prethermalization. Here, we show that
in the Tomonaga-Luttinger model the entanglement prethermalization can also be
explained by the conventional prethermalization of two independent subsystems
without entanglement. Moreover, it is argued that prethermalization in the
Tomonaga-Luttinger model is essentially different from entanglement
prethermalization in the Lieb-Liniger model because of the different types of
energy degeneracies.
| [
"cond-mat.stat-mech",
"cond-mat.quant-gas"
] | cond-mat.stat-mech | cond-mat.quant-gas | Statistical Mechanics;Quantum Gases | 6,947Statistical Mechanics;Quantum Gases
|
1403.7336 | Systematic investigations of the electric dipole (E1) modes of excitation are
performed using the canonical-basis time-dependent Hartree-Fock-Bogoliubov
(Cb-TDHFB) theory. The Cb-TDHFB is able to describe dynamical pairing
correlations in excited states of nuclear systems. We apply the method to the
real-time calculation of linear response in even-even nuclei with Skyrme
functionals. Effects of shell structure, neutron skin, deformation, and neutron
chemical potential (separation energy) are studied in a systematic way. This
reveals a number of characteristic features of the low-energy E1 modes. We also
find a universal behavior in the low-energy E1 modes for heavy neutron-rich
isotopes, which suggests the emergence of decoupled E1 peaks beyond N = 82.
| [
"nucl-th"
] | nucl-th | Nuclear Theory | 4,876Nuclear Theory
|
|
1412.4986 | Learning meaningful topic models with massive document collections which
contain millions of documents and billions of tokens is challenging because of
two reasons: First, one needs to deal with a large number of topics (typically
in the order of thousands). Second, one needs a scalable and efficient way of
distributing the computation across multiple machines. In this paper we present
a novel algorithm F+Nomad LDA which simultaneously tackles both these problems.
In order to handle large number of topics we use an appropriately modified
Fenwick tree. This data structure allows us to sample from a multinomial
distribution over $T$ items in $O(\log T)$ time. Moreover, when topic counts
change the data structure can be updated in $O(\log T)$ time. In order to
distribute the computation across multiple processor we present a novel
asynchronous framework inspired by the Nomad algorithm of
\cite{YunYuHsietal13}. We show that F+Nomad LDA significantly outperform
state-of-the-art on massive problems which involve millions of documents,
billions of words, and thousands of topics.
| [
"cs.DC",
"cs.IR",
"cs.LG"
] | cs.DC | cs.IR | Distributed, Parallel, and Cluster Computing;Information Retrieval;Machine Learning | 7,267longtail
|
1707.08400 | The latest MERRA-2 reanalysis of the modern satellite measurements provides
unprecedented uniformity and fidelity for the atmospheric data. In this paper,
these data are used to evaluate five sites for millimeter-wave (mm-wave)
observations. These include two established sites (South Pole and Chajnantor,
Atacama), and three new sites (Ali, Tibet; Dome A, Antarctica; and Summit Camp,
Greenland). Atmospheric properties including precipitable water vapor (PWV),
sky brightness temperature fluctuations, ice and liquid water paths are derived
and compared. Dome A emerges to be the best among those evaluated, with PWV and
fluctuations smaller than the second-best site, South Pole, by more than a
factor of 2. It is found that the higher site in Ali (6,100 m) is on par with
Cerro Chajnantor (5,612 m) in terms of transmission and stability. The lower
site in Ali (5,250 m) planned for first stage of observations at 90/150GHz
provides conditions comparable to those on the Chajnantor Plateau. These
analyses confirm Ali to be an excellent mm-wave site on the Northern Hemisphere
that will complement well-established sites on the Southern Hemisphere. It is
also found in this analysis that the observing conditions at Summit Camp are
comparable to Cerro Chajnantor. Although it is more affected by the presence of
liquid water clouds.
| [
"astro-ph.IM",
"astro-ph.CO"
] | astro-ph.IM | astro-ph.CO | Instrumentation and Methods for Astrophysics;Cosmology and Nongalactic Astrophysics | 3,706Instrumentation and Methods for Astrophysics;Cosmology and Nongalactic Astrophysics
|
1711.04235 | Bitcoin is a digital currency and payment system based on classical
cryptographic technologies which works without a central administrator such as
in traditional currencies. It has long been questioned what the impact of
quantum computing would be on Bitcoin, and cryptocurrencies in general. Here,
we analyse three primary directions that quantum computers might have an impact
in: mining, security, and forks. We find that in the near-term the impact of
quantum computers appear to be rather small for all three directions. The
impact of quantum computers would require considerably larger number of qubits
and breakthroughs in quantum algorithms to reverse existing hash functions.
| [
"quant-ph",
"cs.CR"
] | quant-ph | cs.CR | Quantum Physics;Cryptography and Security | 6,032Quantum Physics;Cryptography and Security
|
2101.03884 | We conducted an investigation to find when a mistake was introduced in a
widely accessed Internet document, namely the RFC index. With great surprise,
we discovered that a it may go unnoticed for a very long period, namely more
that twenty-six years. This raises some questions to what does it mean to have
open access and the meaning of Linus' laws that "given enough eyeballs, all
bugs are shallow"
| [
"cs.DL"
] | cs.DL | Digital Libraries | 2,081Digital Libraries
|
|
2004.06283 | Higher-order topological phases are characterized by protected states
localized at the corners or hinges of the system. By applying time-periodic
quenches to a two-dimensional lattice with balanced gain and loss, we obtain a
rich variety of non-Hermitian Floquet second order topological insulating
phases. Each of the phases is characterized by a pair of integer topological
invariants, which predict the numbers of Floquet corner modes at zero and $\pi$
quasienergies. We establish the topological phase diagram of the model, and
find a series of non-Hermiticity induced transitions between different Floquet
second order topological phases. We further generalize the mean chiral
displacement to two-dimensional non-Hermitian systems, and use it to extract
the topological invariants of our model dynamically. This work thus extend the
study of higher-order topological matter to more generic nonequilibrium
settings, in which the interplay between Floquet engineering and
non-Hermiticity yields fascinating new phases.
| [
"cond-mat.mes-hall"
] | cond-mat.mes-hall | Mesoscale and Nanoscale Physics | 4,450Mesoscale and Nanoscale Physics
|
|
1308.5084 | I combine recent results in the structure theory of nuclear C*-algebras and
in topological dynamics to classify certain types of crossed products in terms
of their Elliott invariants. In particular, transformation group C*-algebras
associated to free minimal Z^d-actions on the Cantor set with compact space of
ergodic measures are classified by their ordered K-theory. In fact, the
respective statement holds for finite dimensional compact metrizable spaces,
provided that projections of the crossed products separate tracial states.
Moreover, C*-algebras associated to certain minimal homeomorphisms of odd
dimensional spheres are only determined by their spaces of invariant Borel
probability measures (without a condition on the space of ergodic measures).
Finally, I show that for a large collection of classifiable C*-algebras,
crossed products by Z^d-actions are generically again classifiable.
| [
"math.OA"
] | math.OA | Operator Algebras | 5,107Operator Algebras
|
|
cs/0208002 | The pit recording of file, the coefficient of compression are introduced. The
theoretical limit of the information compression as minimal coefficient of
compression for the given length of alphabet are found.
| [
"cs.CR"
] | cs.CR | Cryptography and Security | 1,782Cryptography and Security
|
|
1611.00599 | An optical translational projector (OTP) designed by transformation optics is
applied to improve the energy transfer efficiency in a wireless energy transfer
(WET) system. Numerical simulation results show our OTP can greatly enhance the
energy transfer efficiency (e.g. nearly 2 orders, compared to the case without
our OTP) in WET systems, which is much larger than previous methods (e.g.
magnetic super-lens). A 3D reduced OTP composed by layered isotropic magnetic
materials is designed, whose performance has been verified by 3D numerical
simulations in 10MHz. We also study the influence of loss of metamaterials on
the performance of proposed OTP.
| [
"physics.gen-ph"
] | physics.gen-ph | General Physics | 2,645General Physics
|
|
2208.01255 | We prove that the localization of the monoidal category $\mathcal{C}_w$ is
rigid, and the category $\mathcal{C}_{w,v}$ admits a localization via a real
commuting family of central objects. Note that the localization of
$\mathcal{C}_{w,v}$ categorifies the open Richardson variety.
| [
"math.RT",
"math.QA"
] | math.RT | math.QA | Representation Theory;Quantum Algebra | 6,268Representation Theory;Quantum Algebra
|
1411.0953 | We obtain a refinement of the degrees of freedom estimate of Landau and
Pollak. More precisely, we estimate, in terms of $\epsilon$, the increase in
the degrees of freedom resulting upon allowing the functions to contain a
certain prescribed amount of energy $\epsilon $ outside a region delimited by a
set $T$ in time and a set $\Omega $ in frequency. In this situation, the lower
asymptotic Nyquist density $\vert T\vert \vert \Omega \vert /2\pi$ is increased
to $(1+\epsilon)\vert T\vert \vert \Omega \vert /2\pi$. At the technical level,
we prove a pseudospectra version of the classical spectral dimension result of
Landau and Pollak, in the multivariate setting of Landau. Analogous results are
obtained for Gabor localization operators in a compact region of the
time-frequency plane.
| [
"math.FA"
] | math.FA | Functional Analysis | 2,549Functional Analysis
|
|
1602.01189 | In this article, we examine the behavior of the Riemannian and Hermitian
curvature tensors of a Hermitian metric, when one of the curvature tensors
obeys all the symmetry conditions of the curvature tensor of a K\"ahler metric.
We will call such metrics G-K\"ahler-like or K\"ahler-like, for lack of better
terminologies. Such metrics are always balanced when the manifold is compact,
so in a way they are more special than balanced metrics, which drew a lot of
attention in the study of non-K\"ahler Calabi-Yau manifolds. In particular we
derive various formulas on the difference between the Riemannian and Hermitian
curvature tensors in terms of the torsion of the Hermitian connection. We
believe that these formulas could lead to further applications in the study of
Hermitian geometry with curvature assumptions.
| [
"math.DG"
] | math.DG | Differential Geometry | 2,010Differential Geometry
|
|
1404.1196 | We show that some curvature operators are locally invertible, in some
weithted sobolev spaces, near the euclidian metric. (Nous montrons que certains
op\'erateurs affines en la courbure de Ricci sont localement inversibles, dans
des espaces de Sobolev \`a poids, au voisinage de la m\'etrique euclidienne.)
| [
"math.DG",
"math.AP"
] | math.DG | math.AP | Differential Geometry;Analysis of PDEs | 2,022Differential Geometry;Analysis of PDEs
|
1804.04139 | The virial masses of ultra-diffuse galaxies (UDGs) have been estimated using
the kinematics and abundance of their globular cluster populations, leading to
disparate results. Some studies conclude that UDGs reside in massive dark
matter halos while others, controversially, argue for the existence of UDGs
with no dark matter at all. Here we show that these results arise because the
uncertainties of these mass estimates have been substantially underestimated.
Indeed, applying the same procedure to the well-studied Fornax dwarf spheroidal
would conclude that it has an "overmassive" dark halo or, alternatively, that
it lacks dark matter. We corroborate our argument with self-consistent mocks of
tracers in cosmological halos, showing that masses from samples with $5 < N <
10$ tracers (assuming no measurement errors) are uncertain by at least an order
of magnitude. Finally, we estimate masses of UDGs with HST imaging in Coma and
show that their recent mass measurements (with adequate uncertainties) are in
agreement with that of other dwarfs, such as Fornax.. We also provide bias and
scatter factors for a range of sample sizes and measurement errors, of wider
applicability.
| [
"astro-ph.GA"
] | astro-ph.GA | Astrophysics of Galaxies | 464Astrophysics of Galaxies
|
|
math/0111116 | Let X be a Fano manifold. G.Tian proves that if X admits a Kaehler-Einstein
metric, then it satisfies two different stability conditions: one involving the
Futaki invariant of a special degeneration of X, the other
Hilbert-Mumford-stability of X w.r.t. a certain polarization. He conjectures
that each of these conditions is also sufficient for the existence of such a
metric. If this is true, then in particular the two stability conditions would
be equivalent. We show that for Fano hypersurfaces in projective space, where
due to the work of Lu and Yotov an explicit formula for the Futaki invariant is
known, these two conditions are indeed very closely related.
| [
"math.AG",
"math.DG"
] | math.AG | math.DG | Algebraic Geometry;Differential Geometry | 99Algebraic Geometry;Differential Geometry
|
astro-ph/9804099 | We investigate the nature of stellar populations of major galaxy mergers
between late-type spirals considerably abundant in interstellar medium by
performing numerical simulations designed to solve both the dynamical and
chemical evolution in a self-consistent manner. We particularly consider that
the star formation history of galaxy mergers is a crucial determinant for the
nature of stellar populations of merger remnants, and therefore investigate how
the difference in star formation history between galaxy mergers affects the
chemical evolution of galaxy mergers. We found that the rapidity of star
formation, which is defined as the ratio of the dynamical time-scale to the
time-scale of gas consumption by star formation, is the most important
determinant for a number of fundamental characteristics of stellar populations
of merger remnants. We mainly demonstrate that even the chemical evolution of
elliptical galaxies can be strongly affected by the details of dynamical
evolution of galaxy merging. Based upon the present numerical results, we adopt
a specific assumption of the luminosity dependence of the rapidity of star
formation and thereby discuss how successfully the present merger model can
reproduce a number of fundamental chemical, photometric, and spectroscopic
characteristics of elliptical galaxies.
| [
"astro-ph"
] | astro-ph | Astrophysics | 463Astrophysics
|
|
2401.05681 | We investigate the low moments $\mathbb{E}[|A_N|^{2q}],\, 0<q\leq 1$ of
secular coefficients $A_N$ of the critical non-Gaussian holomorphic
multiplicative chaos, i.e. coefficients of $z^N$ in the power series expansion
of $\exp(\sum_{k=1}^\infty X_kz^k/\sqrt{k})$, where $\{X_k\}_{k\geq 1}$ are
i.i.d. rotationally invariant unit variance complex random variables. Inspired
by Harper's remarkable result on random multiplicative functions, Soundararajan
and Zaman recently showed that if each $X_k$ is standard complex Gaussian,
$A_N$ features better-than-square-root cancellation: $\mathbb{E}[|A_N|^2]=1$
and $\mathbb{E}[|A_N|^{2q}]\asymp (\log N)^{-q/2}$ for fixed $q\in(0,1)$ as
$N\to\infty$. We show that this asymptotic holds universally if
$\mathbb{E}[e^{\gamma|X_k|}]<\infty$ for some $\gamma>2q$. As a consequence, we
establish the universality for the sharp tightness of the normalized secular
coefficients $A_N(\log(1+N))^{1/4}$ of critical holomorphic chaos, generalizing
a result of Najnudel, Paquette, and Simm. Moreover, we completely characterize
the asymptotic of $\mathbb{E}[|A_N|^{2q}]$ for $|X_k|$ following a stretched
exponential distribution with an arbitrary scale parameter, which exhibits a
completely different behavior and underlying mechanism from the universality
regime. As a result, we unveil a double-layer phase transition, occurring at
exponential-type tails and exponential tails of parameter $2q$. Our proofs
combine the robustness of Harper's multiplicative chaos approach and a careful
analysis of the (possibly random) leading terms in the monomial decomposition
of $A_N$.
| [
"math.PR"
] | math.PR | Probability | 5,709Probability
|
|
math/9803084 | Let M be the cotangent bundle of S^2, with the standard symplectic structure.
By adapting an argument of Gromov we determine the weak homotopy type of the
group S of those symplectic automorphisms of M which are trivial at infinity.
It turns out that S is weakly homotopy equivalent to \Z. \pi_0(S) is generated
by the class of the standard "generalized Dehn twist". As a consequence, we
show that there are different connected components of S which lie in the same
connected component of the corresponding group of diffeomorphisms.
| [
"math.DG"
] | math.DG | Differential Geometry | 2,010Differential Geometry
|
|
1403.6966 | Gibbs free energy models are derived from the calculated electronic and
phonon structure of two possible models of $\gamma$-alumina, a defective spinel
phase and a hydrogenated spinel phase. The intrinsic vacancies and hydrogen in
the two structural models give rise to a considerable configurational
(residual) entropy and significantly contribute to thermodynamic stability and
physical-chemical properties of $\gamma$-alumina, which was neglected in
previous studies but considered in this work. The electronic densities of
states, calculated using a hybrid functional for the two structural models of
$\gamma$-alumina, are presented. The dynamic stability of the two phases is
confirmed by full-spectrum phonon calculations. The two phases share many
similarities in their electronic structure, but can be distinguished by their
vibrational spectra and specific heat. The defective spinel is found to be the
ground state of $\gamma$-alumina, while the hydrogenated spinel to be a
metastable phase. However, dehydration of the metastable phase into the ground
state is expected to be slow due to the low diffusion rate of H, which leaves
hydrogen as a locked-in impurity in $\gamma$-alumina.
| [
"cond-mat.mtrl-sci"
] | cond-mat.mtrl-sci | Materials Science | 4,287Materials Science
|
|
1905.01320 | Meta-learning is a tool that allows us to build sample-efficient learning
systems. Here we show that, once meta-trained, LSTM Meta-Learners aren't just
faster learners than their sample-inefficient deep learning (DL) and
reinforcement learning (RL) brethren, but that they actually pursue
fundamentally different learning trajectories. We study their learning dynamics
on three sets of structured tasks for which the corresponding learning dynamics
of DL and RL systems have been previously described: linear regression (Saxe et
al., 2013), nonlinear regression (Rahaman et al., 2018; Xu et al., 2018), and
contextual bandits (Schaul et al., 2019). In each case, while
sample-inefficient DL and RL Learners uncover the task structure in a staggered
manner, meta-trained LSTM Meta-Learners uncover almost all task structure
concurrently, congruent with the patterns expected from Bayes-optimal inference
algorithms. This has implications for research areas wherever the learning
behaviour itself is of interest, such as safety, curriculum design, and
human-in-the-loop machine learning.
| [
"cs.LG",
"cs.AI",
"stat.ML"
] | cs.LG | cs.AI | Machine Learning;Artificial Intelligence;Machine Learning | 3,951Machine Learning;Artificial Intelligence;Machine Learning
|
2112.09260 | The Vision Transformer (ViT) architecture has recently achieved competitive
performance across a variety of computer vision tasks. One of the motivations
behind ViTs is weaker inductive biases, when compared to convolutional neural
networks (CNNs). However this also makes ViTs more difficult to train. They
require very large training datasets, heavy regularization, and strong data
augmentations. The data augmentation strategies used to train ViTs have largely
been inherited from CNN training, despite the significant differences between
the two architectures. In this work, we empirical evaluated how different data
augmentation strategies performed on CNN (e.g., ResNet) versus ViT
architectures for image classification. We introduced a style transfer data
augmentation, termed StyleAug, which worked best for training ViTs, while
RandAugment and Augmix typically worked best for training CNNs. We also found
that, in addition to a classification loss, using a consistency loss between
multiple augmentations of the same image was especially helpful when training
ViTs.
| [
"cs.CV"
] | cs.CV | Computer Vision and Pattern Recognition | 1,498Computer Vision and Pattern Recognition
|
|
2107.09101 | Automotive Cyber-Physical Systems (ACPS) have attracted a significant amount
of interest in the past few decades, while one of the most critical operations
in these systems is the perception of the environment. Deep learning and,
especially, the use of Deep Neural Networks (DNNs) provides impressive results
in analyzing and understanding complex and dynamic scenes from visual data. The
prediction horizons for those perception systems are very short and inference
must often be performed in real time, stressing the need of transforming the
original large pre-trained networks into new smaller models, by utilizing Model
Compression and Acceleration (MCA) techniques. Our goal in this work is to
investigate best practices for appropriately applying novel weight sharing
techniques, optimizing the available variables and the training procedures
towards the significant acceleration of widely adopted DNNs. Extensive
evaluation studies carried out using various state-of-the-art DNN models in
object detection and tracking experiments, provide details about the type of
errors that manifest after the application of weight sharing techniques,
resulting in significant acceleration gains with negligible accuracy losses.
| [
"cs.CV",
"cs.LG"
] | cs.CV | cs.LG | Computer Vision and Pattern Recognition;Machine Learning | 1,593Computer Vision and Pattern Recognition;Machine Learning
|
1506.04482 | We investigate the hole spin relaxation due to the Rashba spin-orbit coupling
induced by an external perpendicular electric field in bilayer WSe$_2$. The
Rashba spin-orbit coupling coefficients in bilayer WSe$_2$ are constructed from
the corresponding monolayer ones. In contrast to monolayer WSe$_2$, the
out-of-plane component of the bilayer Rashba spin-orbit coupling acts as a
Zeeman-like field with opposite directions but identical values in the two
valleys. For in-plane spins, this Zeeman-like field, together with the
intervalley hole-phonon scattering, opens an intervalley spin relaxation
channel, which is found to dominate the in-plane spin relaxation in bilayer
WSe$_2$ even at low temperature. For out-of-plane spins, this Zeeman-like field
is superimposed by the identical Hartree-Fock effective magnetic fields in the
two valleys, and hence different total effective magnetic fields between two
valleys are obtained. Owing to the large difference of the total fields at
large spin polarization, different out-of-plane spin relaxation times in the
two valleys are obtained when the intervalley hole-phonon scattering is weak at
low temperature and low hole density. This difference in the spin relaxation
times can be suppressed by enhancing the intervalley hole-phonon scattering
through increasing temperature or hole density. Moreover, at large spin
polarization and low temperature, due to the weak intravalley hole-phonon
scattering but relatively strong hole-hole Coulomb scattering, the fast spin
precessions are found to result in a quasi hot-hole Fermi distribution
characterized by an effective hot-hole temperature larger than the temperature,
which also enhances the intervalley scattering. During this process, it is
interesting to discover that the initially equal hole densities in the two
valleys are broken in the temporal evolution, and a valley polarization is
built up. ....
| [
"cond-mat.mes-hall"
] | cond-mat.mes-hall | Mesoscale and Nanoscale Physics | 4,450Mesoscale and Nanoscale Physics
|
|
2303.01342 | In many histopathology tasks, sample classification depends on morphological
details in tissue or single cells that are only visible at the highest
magnification. For a pathologist, this implies tedious zooming in and out,
while for a computational decision support algorithm, it leads to the analysis
of a huge number of small image patches per whole slide image (WSI).
Attention-based multiple instance learning (MIL), where attention estimation is
learned in a weakly supervised manner, has been successfully applied in
computational histopathology, but it is challenged by large numbers of
irrelevant patches, reducing its accuracy. Here, we present an active learning
approach to the problem. Querying the expert to annotate regions of interest in
a WSI guides the formation of high-attention regions for MIL. We train an
attention-based MIL and calculate a confidence metric for every image in the
dataset to select the most uncertain WSIs for expert annotation. We test our
approach on the CAMELYON17 dataset classifying metastatic lymph node sections
in breast cancer. With a novel attention guiding loss, this leads to an
accuracy boost of the trained models with few regions annotated for each class.
Active learning thus improves WSIs classification accuracy, leads to faster and
more robust convergence, and speeds up the annotation process. It may in the
future serve as an important contribution to train MIL models in the clinically
relevant context of cancer classification in histopathology.
| [
"cs.CV",
"eess.IV"
] | cs.CV | eess.IV | Computer Vision and Pattern Recognition;Image and Video Processing | 1,584Computer Vision and Pattern Recognition;Image and Video Processing
|
2106.01102 | We consider singular quasilinear stochastic partial differential equations
(SPDEs) studied in \cite{FHSX}, which are defined in paracontrolled sense. The
main aim of the present article is to establish the global-in-time solvability
for a particular class of SPDEs with origin in particle systems and, under a
certain additional condition on the noise, prove the convergence of the
solutions to stationary solutions as $t\to\infty$. We apply the method of
energy inequality and Poincar\'e inequality. It is essential that the
Poincar\'e constant can be taken uniformly in an approximating sequence of the
noise. We also use the continuity of the solutions in the enhanced noise,
initial values and coefficients of the equation, which we prove in this article
for general SPDEs discussed in \cite{FHSX} except that in the enhanced noise.
Moreover, we apply the initial layer property of improving regularity of the
solutions in a short time.
| [
"math.PR"
] | math.PR | Probability | 5,709Probability
|
|
hep-th/0401061 | In this paper, we give a general axiomatization of anomalies in closed and
open conformal field theories. In particular, we generalize Segal's notion of
modular functor to a setting where the ``set of labels'' is a 2-vector space.
In the case of open conformal field theory, the ``set of $D$-branes'' is a
3-vector space. We also define a ``topological group completion'' of the
symmetric bimonoidal category of finite-dimensional vector spaces, and propose
it as a candidate for labelling conformal field theories whose modular functors
are super-vector spaces.
| [
"hep-th"
] | hep-th | High Energy Physics - Theory | 3,266High Energy Physics - Theory
|
|
2001.07626 | We present a novel method for proposal free instance segmentation that can
handle sophisticated object shapes which span large parts of an image and form
dense object clusters with crossovers. Our method is based on predicting dense
local shape descriptors, which we assemble to form instances. All instances are
assembled simultaneously in one go. To our knowledge, our method is the first
non-iterative method that yields instances that are composed of learnt shape
patches. We evaluate our method on a diverse range of data domains, where it
defines the new state of the art on four benchmarks, namely the ISBI 2012 EM
segmentation benchmark, the BBBC010 C. elegans dataset, and 2d as well as 3d
fluorescence microscopy data of cell nuclei. We show furthermore that our
method also applies to 3d light microscopy data of Drosophila neurons, which
exhibit extreme cases of complex shape clusters
| [
"cs.CV"
] | cs.CV | Computer Vision and Pattern Recognition | 1,498Computer Vision and Pattern Recognition
|
|
2112.14295 | We explore the parameter space of the type-II two-Higgs-doublet model with
softly broken Z2 symmetry, allowing for CP violation in the scalar potential.
Imposing theory-motivated and experimentally-driven constraints, we show that
as the CP-violating phases are increased, only small regions of parameter space
survive, including regions slightly away from the alignment limit. Electroweak
oblique parameters and electric dipole moments emerge as most restrictive
constraints. We show that imposing these constraints (as well as theoretical
bounds such as perturbativity) the masses of the charged and heavy neutral
Higgs, unlike in the CP conserving case, are bound from above and below. In
particular, the heavy neutral Higgs masses are almost degenerate. In this
parameter space region we highlight the relevant decay signals of the heavy
neutral Higgs, involving both Zh and WW=ZZ, indicative of CP violation in the
model.
| [
"hep-ph"
] | hep-ph | High Energy Physics - Phenomenology | 3,129High Energy Physics - Phenomenology
|
|
nucl-th/0412035 | Isobaric models for the photo-production of K$^+$ are discussed and their
predictions are shown in the K$^0$ photo-production. The models are further
used in spectator model calculations of the K$^0$ photo-production on deuteron.
Considerable dependence of the inclusive cross section on the elementary
amplitude was found.
| [
"nucl-th"
] | nucl-th | Nuclear Theory | 4,876Nuclear Theory
|
|
1901.03987 | Ultrasound detection via silicon waveguides relies on the ability of acoustic
waves to modulate the effective refractive index of the guided modes. However,
the low photo-elastic response of silicon and silica limits the sensitivity of
conventional silicon-on-insulator (SOI) sensors, in which the silicon core is
surrounded by a silica cladding. In this paper, we demonstrate that the
sensitivity of silicon waveguides to ultrasound may be significantly enhanced
by replacing the silica over-cladding with bisbenzocyclobutene (BCB) - a
transparent polymer with a high photo-elastic coefficient. In our experimental
study, the response to ultrasound, in terms of the induced modulation in the
effective refractive index, achieved for a BCB-coated silicon waveguide with TM
polarization was comparable to values previously reported for polymer
waveguides and an order of magnitude higher than the response achieved by an
optical fiber. In addition, in our study the susceptibility of the sensors to
surface acoustic waves and reverberations was reduced for both TE and TM modes
when the BCB over-cladding was used.
| [
"physics.optics",
"physics.app-ph"
] | physics.optics | physics.app-ph | Optics;Applied Physics | 5,150Optics;Applied Physics
|
1011.5565 | The orthogonal group acts on the space of several $n\times n$ matrices by
simultaneous conjugation. For an infinite field of characteristic different
from two, relations between generators for the algebra of invariants are
described. As an application, the maximal degree of elements of a minimal
system of generators is described with deviation $3$.
This note contains concise but precise description of the results. All proofs
can be found in arXiv: 0902.4266 and arXiv: 1011.5201.
| [
"math.RT",
"math.AG",
"math.RA"
] | math.RT | math.AG | Representation Theory;Algebraic Geometry;Rings and Algebras | 6,224Representation Theory;Algebraic Geometry;Rings and Algebras
|
1810.10909 | In this paper, we present CAIO, a Cognitive and Affective
Interaction-Oriented architecture for social human-robot interactions (HRI),
allowing robots to reason on mental states (including emotions), and to act
physically, emotionally and verbally. We also present a short scenario and
implementation on a Nao robot.
| [
"cs.AI",
"cs.RO"
] | cs.AI | cs.RO | Artificial Intelligence;Robotics | 453Artificial Intelligence;Robotics
|
gr-qc/9901073 | We describe a simple dynamical model characterized by the presence of two
noncommuting Hamiltonian constraints. This feature mimics the constraint
structure of general relativity, where there is one Hamiltonian constraint
associated with each space point. We solve the classical and quantum dynamics
of the model, which turns out to be governed by an SL(2,R) gauge symmetry,
local in time. In classical theory, we solve the equations of motion, find a
SO(2,2) algebra of Dirac observables, find the gauge transformations for the
Lagrangian and canonical variables and for the Lagrange multipliers. In quantum
theory, we find the physical states, the quantum observables, and the physical
inner product, which is determined by the reality conditions. In addition, we
construct the classical and quantum evolving constants of the system. The model
illustrates how to describe physical gauge-invariant relative evolution when
coordinate time evolution is a gauge.
| [
"gr-qc",
"hep-th",
"quant-ph"
] | gr-qc | hep-th | General Relativity and Quantum Cosmology;High Energy Physics - Theory;Quantum Physics | 2,756General Relativity and Quantum Cosmology;High Energy Physics - Theory;Quantum Physics
|
2205.07083 | This paper investigates different pretraining approaches to spoken language
identification. The paper is based on our submission to the Oriental Language
Recognition 2021 Challenge. We participated in two tracks of the challenge:
constrained and unconstrained language recognition. For the constrained track,
we first trained a Conformer-based encoder-decoder model for multilingual
automatic speech recognition (ASR), using the provided training data that had
transcripts available. The shared encoder of the multilingual ASR model was
then finetuned for the language identification task. For the unconstrained
task, we relied on both externally available pretrained models as well as
external data: the multilingual XLSR-53 wav2vec2.0 model was finetuned on the
VoxLingua107 corpus for the language recognition task, and finally finetuned on
the provided target language training data, augmented with CommonVoice data.
Our primary metric $C_{\rm avg}$ values on the Test set are 0.0079 for the
constrained task and 0.0119 for the unconstrained task which resulted in the
second place in both rankings. In post-evaluation experiments, we study the
amount of target language data needed for training an accurate backend model,
the importance of multilingual pretraining data, and compare different models
as finetuning starting points.
| [
"eess.AS",
"cs.CL"
] | eess.AS | cs.CL | Audio and Speech Processing;Computation and Language | 648Audio and Speech Processing;Computation and Language
|
1904.03587 | In this study, a graph-computing based grid splitting detection algorithm is
proposed for contingency analysis in a graph-based EMS (Energy Management
System). The graph model of a power system is established by storing its
bus-branch information into the corresponding vertex objects and edge objects
of the graph database. Numerical comparison to an up-to-date serial computing
algorithm is also investigated. Online tests on a real power system of China
State Grid with 2752 buses and 3290 branches show that a 6 times speedup can be
achieved, which lays a good foundation for advanced contingency analysis.
| [
"cs.DC",
"cs.DB",
"cs.DS"
] | cs.DC | cs.DB | Distributed, Parallel, and Cluster Computing;Databases;Data Structures and Algorithms | 2,217Distributed, Parallel, and Cluster Computing;Databases;Data Structures and Algorithms
|