id
stringlengths 9
16
| abstract
stringlengths 67
2.61k
| cats
sequence | primary
stringlengths 5
18
| secondary
stringlengths 0
18
| strlabel
stringlengths 5
315
| stratlabel
class label 7.27k
classes |
|---|---|---|---|---|---|---|
1909.00997 | Existing synthetic datasets (FigureQA, DVQA) for reasoning over plots do not
contain variability in data labels, real-valued data, or complex reasoning
questions. Consequently, proposed models for these datasets do not fully
address the challenge of reasoning over plots. In particular, they assume that
the answer comes either from a small fixed size vocabulary or from a bounding
box within the image. However, in practice, this is an unrealistic assumption
because many questions require reasoning and thus have real-valued answers
which appear neither in a small fixed size vocabulary nor in the image. In this
work, we aim to bridge this gap between existing datasets and real-world plots.
Specifically, we propose PlotQA with 28.9 million question-answer pairs over
224,377 plots on data from real-world sources and questions based on
crowd-sourced question templates. Further, 80.76% of the out-of-vocabulary
(OOV) questions in PlotQA have answers that are not in a fixed vocabulary.
Analysis of existing models on PlotQA reveals that they cannot deal with OOV
questions: their overall accuracy on our dataset is in single digits. This is
not surprising given that these models were not designed for such questions. As
a step towards a more holistic model which can address fixed vocabulary as well
as OOV questions, we propose a hybrid approach: Specific questions are answered
by choosing the answer from a fixed vocabulary or by extracting it from a
predicted bounding box in the plot, while other questions are answered with a
table question-answering engine which is fed with a structured table generated
by detecting visual elements from the image. On the existing DVQA dataset, our
model has an accuracy of 58%, significantly improving on the highest reported
accuracy of 46%. On PlotQA, our model has an accuracy of 22.52%, which is
significantly better than state of the art models.
| [
"cs.CV",
"cs.AI",
"cs.CL"
] | cs.CV | cs.AI | Computer Vision and Pattern Recognition;Artificial Intelligence;Computation and Language | 1,503Computer Vision and Pattern Recognition;Artificial Intelligence;Computation and Language
|
cond-mat/0505502 | For Small World Ising systems of different dimensions, "concentration"
dependencies T_C(p) of the Curie temperature upon the fraction p of long-range
links have been derived on a basis of simple physical considerations. We have
found T_C(p) ~ 1/ln|p| for 1D, T_C(p) ~ p^{1/2} for 2D, and T_C(p) ~ p^{2/3}
for 3D.
| [
"cond-mat.dis-nn"
] | cond-mat.dis-nn | Disordered Systems and Neural Networks | 2,129Disordered Systems and Neural Networks
|
|
2112.03952 | We present a calculation of the connected-diagram contributions to the first
three non-trivial Mellin moments for the pion and kaon, extracted using local
operators with up to 3 covariant derivatives. We use one ensemble of gauge
configurations with two degenerate light, a strange and a charm quark
($N_f$=2+1+1) of maximally twisted mass fermions with clover improvement. The
ensemble has a pion mass $\sim$260 MeV, and a kaon mass $\sim$530 MeV. We
reconstruct the $x$-dependence of the PDFs via fits to our results, and find
that our lattice data favor a $(1-x)^2$-behavior in the large-$x$ region for
both the pion and kaon PDFs. We integrate the reconstructed PDFs to extract the
higher moments, $\langle x^n \rangle$, with $4 \leq n \leq 6$. Finally, we
compare the pion and kaon PDFs, as well as the ratios of their Mellin moments,
to address the effect of SU(3) flavor symmetry breaking.
| [
"hep-lat",
"hep-ph",
"nucl-th"
] | hep-lat | hep-ph | High Energy Physics - Lattice;High Energy Physics - Phenomenology;Nuclear Theory | 3,109High Energy Physics - Lattice;High Energy Physics - Phenomenology;Nuclear Theory
|
1301.3724 | Cosmic explosions dissipate energy into their surroundings on a very wide
range of time-scales: producing shock waves and associated particle
acceleration. The historical culprits for the acceleration of the bulk of
Galactic cosmic rays are supernova remnants: explosions on ~10000 year
time-scales. Increasingly however, time-variable emission points to rapid and
efficient particle acceleration in a range of different astrophysical systems.
Gamma-ray bursts have the shortest time-scales, with inferred bulk Lorentz
factors of ~1000 and photons emitted beyond 100 GeV, but active galaxies,
pulsar wind nebulae and colliding stellar winds are all now associated with
time-variable emission at ~TeV energies. Cosmic photons and neutrinos at these
energies offer a powerful probe of the underlying physical mechanisms of cosmic
explosions, and a tool for exploring fundamental physics with these systems.
Here we discuss the motivations for high-energy observations of transients, the
current experimental situation, and the prospects for the next decade, with
particular reference to the major next-generation high-energy observatory CTA.
| [
"astro-ph.HE"
] | astro-ph.HE | High Energy Astrophysical Phenomena | 2,990High Energy Astrophysical Phenomena
|
|
1705.06998 | We deduce an analogue of Quillen--Suslin's local-global principle for the
transvection subgroups of the general quadratic (Bak's unitary) groups. As an
application we revisit the result of Bak--Petrov--Tang on injective
stabilization for the K_1-functor of the general quadratic groups.
| [
"math.KT"
] | math.KT | K-Theory and Homology | 3,775K-Theory and Homology
|
|
1905.06852 | As more and more applications and services depend on data collected and
provided by Internet of Things (IoT) devices, it is of importance that such
data can be trusted. Data provenance solutions together with blockchain
technology are one way to make data more trustworthy. However, current
solutions do not address the heterogeneous nature of IoT applications and their
data. In this work, we identify functional and non-functional requirements for
a generic IoT data provenance framework, and conceptualise the framework as a
layered architecture. Using a proof-of-concept implementation based on Ethereum
smart contracts, data provenance can be realised for a wide range of IoT use
cases. Benefits of a generic framework include simplified adoption and a more
rapid implementation of data provenance for the IoT.
| [
"cs.CR"
] | cs.CR | Cryptography and Security | 1,782Cryptography and Security
|
|
1406.3398 | Yeast cells grown in culture can spontaneously synchronize their respiration,
metabolism, gene expression and cell division. Such metabolic oscillations in
synchronized cultures reflect single-cell oscillations, but the relationship
between the oscillations in single cells and synchronized cultures is poorly
understood. To understand this relationship and the coordination between
metabolism and cell division, we collected and analyzed DNA-content,
gene-expression and physiological data, at hundreds of time-points, from
cultures metabolically-synchronized at different growth rates, carbon sources
and biomass densities. The data enabled us to extend and generalize an
ensemble-average-over-phases (EAP) model that connects the population-average
gene-expression of asynchronous cultures to the gene-expression dynamics in the
single-cells comprising the cultures. The extended model explains the
carbon-source specific growth-rate responses of hundreds of genes. Our data
demonstrate that for a given growth rate, the frequency of metabolic cycling in
synchronized cultures increases with the biomass density. This observation
underscores the difference between metabolic cycling in synchronized cultures
and in single cells and suggests entraining of the single-cell cycle by a
quorum-sensing mechanism. Constant levels of residual glucose during the
metabolic cycling of synchronized cultures indicate that storage carbohydrates
are required to fuel not only the G1/S transition of the division cycle but
also the metabolic cycle. Despite the large variation in profiled conditions
and in the time-scale of their dynamics, most genes preserve invariant dynamics
of coordination with each other and with the rate of oxygen consumption.
Similarly, the G1/S transition always occurs at the beginning, middle or end of
the high oxygen consumption phases, analogous to observations in human and
drosophila cells.
| [
"q-bio.GN",
"nlin.AO",
"physics.bio-ph",
"q-bio.CB",
"q-bio.PE"
] | q-bio.GN | nlin.AO | Genomics;Adaptation and Self-Organizing Systems;Biological Physics;Cell Behavior;Populations and Evolution | 7,267longtail
|
1004.2864 | The ratio of the $\psi'$ over the $J/\psi$ production cross section in the
dielectron channel has been measured in $\sqrt{s}=$ 200 GeV $p+p$ collisions
with the PHENIX detector at RHIC. The analysis is based on fitting of the
dielectron invariant mass spectra in the area around the $J/\psi$ and $\psi'$
signals in order to extract a ratio $\psi'$ over $J/\psi$ of 0.019$\pm
0.005($stat$)\pm 0.002($sys$)$ and a fractional feed-down contribution to
$J/\psi$ from $\psi^\prime$ of $8.6 \pm 2.5 %$.
| [
"nucl-ex"
] | nucl-ex | Nuclear Experiment | 4,855Nuclear Experiment
|
|
2103.16340 | This paper studies Makespan Minimization in the secretary model. Formally,
jobs, specified by their processing times, are presented in a uniformly random
order. An online algorithm has to assign each job permanently and irrevocably
to one of m parallel and identical machines such that the expected time it
takes to process them all, the makespan, is minimized. We give two
deterministic algorithms. First, a straightforward adaptation of the
semi-online strategy LightLoad provides a very simple algorithm retaining its
competitive ratio of 1.75. A new and sophisticated algorithm is
1.535-competitive. These competitive ratios are not only obtained in
expectation but, in fact, for all but a very tiny fraction of job orders.
Classically, online makespan minimization only considers the worst-case order.
Here, no competitive ratio below 1.885 for deterministic algorithms and 1.581
using randomization is possible. The best randomized algorithm so far is
1.916-competitive. Our results show that classical worst-case orders are quite
rare and pessimistic for many applications. They also demonstrate the power of
randomization when compared to much stronger deterministic reordering models.
We complement our results by providing first lower bounds. A competitive ratio
obtained on nearly all possible job orders must be at least 1.257. This implies
a lower bound of 1.043 for both deterministic and randomized algorithms in the
general model.
| [
"cs.DS"
] | cs.DS | Data Structures and Algorithms | 1,908Data Structures and Algorithms
|
|
2010.13283 | The $0$-trace of a knot is the $4$-manifold represented by the $0$-framing of
the knot. In this manuscript, we survey methods constructing a pair of knots
with diffeomorphic $0$-traces. In particular, we focus on Gompf-Miyazaki's
dualizable pattern, Abe-Jong-Omae-Takeuchi's band presentation, and RGB-diagram
given by Piccirillo and named by the author, and we draw the relations among
these methods directly. As an application, we give a sufficient condition that
two knots obtained by Abe-Jong-Omae-Takeuchi's method coincide.
| [
"math.GT"
] | math.GT | Geometric Topology | 2,813Geometric Topology
|
|
2010.15543 | We characterize the possible groups $E(\mathbb{Z}/N\mathbb{Z})$ arising from
elliptic curves over $\mathbb{Z}/N\mathbb{Z}$ in terms of the groups
$E(\mathbb{F}_p)$, with $p$ varying among the prime divisors of $N$. This
classification is achieved by showing that the infinity part of any elliptic
curve over $\mathbb{Z}/p^e\mathbb{Z}$ is a $\mathbb{Z}/p^e\mathbb{Z}$-torsor,
of which a generator is exhibited. As a first consequence, when
$E(\mathbb{Z}/N\mathbb{Z})$ is a $p$-group, we provide an explicit and sharp
bound on its rank. As a second consequence, when $N = p^e$ is a prime power and
the projected curve $E(\mathbb{F}_p)$ has trace one, we provide an isomorphism
attack to the ECDLP, which works only by means of finite rings arithmetic.
| [
"math.NT",
"math.AG"
] | math.NT | math.AG | Number Theory;Algebraic Geometry | 4,946Number Theory;Algebraic Geometry
|
2007.07652 | Liquid crystal networks combine the orientational order of liquid crystals
with the elastic properties of polymer networks, leading to a vast application
potential in the field of responsive coatings, e.g., for haptic feedback,
self-cleaning surfaces and static and dynamic pattern formation. Recent
experimental work has further paved the way toward such applications by
realizing the fast and reversible surface modulation of a liquid crystal
network coating upon in-plane actuation with an AC electric field. Here, we
construct a Landau-type theory for electrically-responsive liquid crystal
networks and perform Molecular Dynamics simulations to explain the findings of
these experiments and inform on rational design strategies. Qualitatively, the
theory agrees with our simulations and reproduces the salient experimental
features. We also provide a set of testable predictions: the aspect ratio of
the nematogens, their initial orientational order when cross-linked into the
polymer network and the cross-linking fraction of the network all increase the
plasticization time required for the film to macroscopically deform. We
demonstrate that the dynamic response to oscillating electric fields is
characterized by two resonances, which can likewise be influenced by varying
these parameters, providing an experimental handle to fine-tune device design.
| [
"cond-mat.soft",
"cond-mat.mtrl-sci"
] | cond-mat.soft | cond-mat.mtrl-sci | Soft Condensed Matter;Materials Science | 6,577Soft Condensed Matter;Materials Science
|
2304.09572 | This paper presents an ecosystem for personal knowledge graphs (PKG),
commonly defined as resources of structured information about entities related
to an individual, their attributes, and the relations between them. PKGs are a
key enabler of secure and sophisticated personal data management and
personalized services. However, there are challenges that need to be addressed
before PKGs can achieve widespread adoption. One of the fundamental challenges
is the very definition of what constitutes a PKG, as there are multiple
interpretations of the term. We propose our own definition of a PKG,
emphasizing the aspects of (1) data ownership by a single individual and (2)
the delivery of personalized services as the primary purpose. We further argue
that a holistic view of PKGs is needed to unlock their full potential, and
propose a unified framework for PKGs, where the PKG is a part of a larger
ecosystem with clear interfaces towards data services and data sources. A
comprehensive survey and synthesis of existing work is conducted, with a
mapping of the surveyed work into the proposed unified ecosystem. Finally, we
identify open challenges and research opportunities for the ecosystem as a
whole, as well as for the specific aspects of PKGs, which include population,
representation and management, and utilization.
| [
"cs.AI",
"cs.IR"
] | cs.AI | cs.IR | Artificial Intelligence;Information Retrieval | 413Artificial Intelligence;Information Retrieval
|
2010.13227 | At thermal equilibrium, intensive quantities like temperature and pressure
have to be uniform throughout the system, restricting inhomogeneous systems
composed of different phases. The paradigmatic example is the coexistence of
vapor and liquid, a state that can also be observed for active Brownian
particles steadily driven away from equilibrium. Recently, a strategy has been
proposed that allows to predict phase equilibria of active particles [Phys.
Rev. E \textbf{97}, 020602(R)(2018)]. Here we elaborate on this strategy and
formulate it in the framework of a van der Waals theory for active discs. For a
given equation of state, we derive the effective free energy analytically and
show that it yields coexisting densities in very good agreement with numerical
results. We discuss the interfacial tension and the relation to Cahn-Hilliard
models.
| [
"cond-mat.stat-mech"
] | cond-mat.stat-mech | Statistical Mechanics | 6,821Statistical Mechanics
|
|
2006.08709 | We investigate the relationship between the thermal properties of a micro
pulsating heat pipe (MPHP) and the internal flow characteristics. The MPHP
consists of an eleven-turn closed-loop of a meandering square microchannel with
a hydraulic diameter of $350\ {}{\mu}{\rm m}$ engraved on a silicon substrate.
The MPHP charged with Fluorinert FC-72 tends to exhibit higher effective
thermal conductivities for the coolant temperature of $T_{\rm c} = 40\
{}^\circ\mathrm{C}$ compared to $T_{\rm c} = 20\ {}^\circ\mathrm{C}$, and
provides the highest effective thermal conductivity of about $700\ {}{\rm
W/(m{\cdot}K)}$ for $T_{\rm c} = 40\ {}^\circ\mathrm{C}$ and a filling ratio of
48%. Interestingly, we observe two different self-oscillation modes having
different thermal conductivities, even for identical heat input rates. This
tendency indicates a hysteresis of the effective thermal conductivity, which
originates from the difference in the heat input rates at which the MPHP falls
into and recovers from dryout. Subsequently, semantic segmentation-based image
recognition is applied to the recorded flow images to identify the flow
characteristics, successfully extracting four different flow patterns involving
liquid slugs, liquid films, dry walls, and rapid-boiling regions. The image
recognition results indicate that high effective thermal conductivities of the
MPHP relate to stable self-oscillations with large amplitudes and high
frequencies, along with long and thin liquid films beneficial for latent heat
transfer. Finally, we perform numerical simulations of latent/sensible heat
transfer via vapor plugs and of sensible heat transfer via liquid slugs using
the extracted flow patterns as inputs. We find that latent heat transfer via
liquid films accounts for a considerable portion of the overall heat transfer,
while the sensible heat transfer via liquid slugs is much less significant.
| [
"physics.app-ph",
"physics.flu-dyn"
] | physics.app-ph | physics.flu-dyn | Applied Physics;Fluid Dynamics | 329Applied Physics;Fluid Dynamics
|
1101.1026 | We study large-scale structure formation in the presence of a quintessence
component with zero speed of sound in the framework of Eulerian Perturbation
Theory. Due to the absence of pressure gradients, quintessence and dark matter
are comoving and can be studied as a unique fluid in terms of the total energy
density contrast and the common velocity. In this description the clustering of
quintessence enhances the linear term proportional to the velocity divergence
in the continuity equation by a factor (1+w) Omega_Q / Omega_m. This is
responsible for a rapid evolution of the growth rate at low redshifts, and
modifies the standard relation between the velocity divergence and the growth
factor. For the total fluid, the solutions for the linear growth function and
growth rate can be written in integral forms and admit simple fitting formulae,
as in the LambdaCDM case. At second order in perturbation theory, we derive an
explicit expression for the kernels F_2 and G_2. They receive modifications of
the order of the ratio between quintessence and total energy density
perturbations, which affect the corresponding tree-level bispectra. We finally
compute the cumulative signal-to-noise in the power spectrum, bispectrum and
reduced bispectrum, expected for departures from a LambdaCDM cosmology both in
the clustering and smooth quintessence scenarios. The reduced bispectrum, in
particular, receives sensible modifications only in the clustering case and can
potentially be used to detect or rule out the model.
| [
"astro-ph.CO",
"gr-qc",
"hep-th"
] | astro-ph.CO | gr-qc | Cosmology and Nongalactic Astrophysics;General Relativity and Quantum Cosmology;High Energy Physics - Theory | 1,748Cosmology and Nongalactic Astrophysics;General Relativity and Quantum Cosmology;High Energy Physics - Theory
|
hep-th/0006154 | The CPT anomaly, which was first seen in perturbation theory for certain
four-dimensional chiral gauge theories, is also present in the exact result for
a class of two-dimensional chiral U(1) gauge theories on the torus.
Specifically, the chiral determinant for periodic fermion fields changes sign
under a CPT transformation of the background gauge field. There is, in fact, an
anomaly of Lorentz invariance, which allows for the CPT theorem to be
circumvented.
| [
"hep-th"
] | hep-th | High Energy Physics - Theory | 3,266High Energy Physics - Theory
|
|
1711.10352 | The two underlying requirements of face age progression, i.e. aging accuracy
and identity permanence, are not well studied in the literature. In this paper,
we present a novel generative adversarial network based approach. It separately
models the constraints for the intrinsic subject-specific characteristics and
the age-specific facial changes with respect to the elapsed time, ensuring that
the generated faces present desired aging effects while simultaneously keeping
personalized properties stable. Further, to generate more lifelike facial
details, high-level age-specific features conveyed by the synthesized face are
estimated by a pyramidal adversarial discriminator at multiple scales, which
simulates the aging effects in a finer manner. The proposed method is
applicable to diverse face samples in the presence of variations in pose,
expression, makeup, etc., and remarkably vivid aging effects are achieved. Both
visual fidelity and quantitative evaluations show that the approach advances
the state-of-the-art.
| [
"cs.CV"
] | cs.CV | Computer Vision and Pattern Recognition | 1,498Computer Vision and Pattern Recognition
|
|
astro-ph/0601155 | We discuss the detectability of high-redshift galaxies via [CII] 158 micron
line emission by coupling an analytic model with cosmological Smoothed Particle
Hydrodynamics (SPH) simulations that are based on the concordance Lambda cold
dark matter (CDM) model. Our analytic model describes a multiphase interstellar
medium irradiated by the far ultra-violet radiation from local star-forming
regions, and it calculates thermal and ionization equilibrium between cooling
and heating. The model allows us to predict the mass fraction of a cold neutral
medium (CNM) embedded in a warm neutral medium (WNM). Our cosmological SPH
simulations include a treatment of radiative cooling/heating, star formation,
and feedback effects from supernovae and galactic winds. Using our method, we
make predictions for the [CII] luminosity from high-redshift galaxies which can
be directly compared with upcoming observations by the Atacama Large Millimeter
Array (ALMA) and the Space Infrared Telescope for Cosmology and Astrophysics
(SPICA). We find that the number density of high-redshift galaxies detectable
by ALMA and SPICA via [CII] emission depends significantly on the amount of
neutral gas which is highly uncertain. Our calculations suggest that, in a CDM
universe, most [CII] sources at z=3 are faint objects with \Snu < 0.01 mJy.
Lyman-break galaxies (LBGs) brighter than R_AB=23.5 mag are expected to have
flux densities \Snu = 1-3 mJy depending on the strength of galactic wind
feedback. The recommended observing strategy for ALMA and SPICA is to aim at
very bright LBGs or star-forming DRG/BzK galaxies.
| [
"astro-ph"
] | astro-ph | Astrophysics | 463Astrophysics
|
|
2005.12065 | A Locality-Sensitive Hash (LSH) function is called
$(r,cr,p_1,p_2)$-sensitive, if two data-points with a distance less than $r$
collide with probability at least $p_1$ while data points with a distance
greater than $cr$ collide with probability at most $p_2$. These functions form
the basis of the successful Indyk-Motwani algorithm (STOC 1998) for nearest
neighbour problems. In particular one may build a $c$-approximate nearest
neighbour data structure with query time $\tilde O(n^\rho/p_1)$ where
$\rho=\frac{\log1/p_1}{\log1/p_2}\in(0,1)$. That is, sub-linear time, as long
as $p_1$ is not too small. This is significant since most high dimensional
nearest neighbour problems suffer from the curse of dimensionality, and can't
be solved exact, faster than a brute force linear-time scan of the database.
Unfortunately, the best LSH functions tend to have very low collision
probabilities, $p_1$ and $p_2$. Including the best functions for Cosine and
Jaccard Similarity. This means that the $n^\rho/p_1$ query time of LSH is often
not sub-linear after all, even for approximate nearest neighbours!
In this paper, we improve the general Indyk-Motwani algorithm to reduce the
query time of LSH to $\tilde O(n^\rho/p_1^{1-\rho})$ (and the space usage
correspondingly.) Since $n^\rho p_1^{\rho-1} < n \Leftrightarrow p_1 > n^{-1}$,
our algorithm always obtains sublinear query time, for any collision
probabilities at least $1/n$. For $p_1$ and $p_2$ small enough, our improvement
over all previous methods can be \emph{up to a factor $n$} in both query time
and space.
The improvement comes from a simple change to the Indyk-Motwani algorithm,
which can easily be implemented in existing software packages.
| [
"cs.DS"
] | cs.DS | Data Structures and Algorithms | 1,908Data Structures and Algorithms
|
|
1906.02504 | We report experimental observation of incoherently coupled dark-bright vector
solitons in single-mode fibers. Properties of the vector solitons agree well
with those predicted by the respective systems of incoherently coupled
nonlinear Schroedinger equations. To the best of our knowledge, this is the
first experimental observation of temporal incoherently coupled dark-bright
solitons in single-mode fibers.
| [
"physics.optics",
"nlin.PS"
] | physics.optics | nlin.PS | Optics;Pattern Formation and Solitons | 5,217Optics;Pattern Formation and Solitons
|
1503.04180 | Societies consisting of cooperative individuals seem to require for their
continuing success that defectors be policed. The precise connection between
punishers and benefits, population structure, and division of labour, however,
remains ill-understood. Many models assume costly "peer punishment" to enforce
cooperation, but results in the economics literature suggest that this
assumption may not be generally valid. In many human and animal societies,
there is a division of labour between a purely supportive majority and a
dedicated minority of police-like enforcers. Here we present several extensions
to the Public Goods Game with punishment which allow for this possibility, and
evaluate their influence on the level of cooperative behaviour. We find that a
structure of separate subpopulations, which only interact through migration of
individuals, can have a strong effect on the evolutionary dynamics of a system
and significantly facilitate cooperation. Forcing defectors to contribute and
enabling fitness transfers to punishers both have a weak positive effect on
cooperation levels. In the presence of group competition, however, evolutionary
effects can paradoxically hinder cooperation.
| [
"q-bio.PE",
"physics.soc-ph"
] | q-bio.PE | physics.soc-ph | Populations and Evolution;Physics and Society | 5,666Populations and Evolution;Physics and Society
|
0801.0371 | If ultra-high-energy cosmic rays (UHECRs) originate from extragalactic
sources, understanding the propagation of charged particles through the
magnetized large scale structure (LSS) of the universe is crucial in the search
for the astrophysical accelerators. Based on a novel model of the turbulence
dynamo, we estimate the intergalactic magnetic fields (IGMFs) in cosmological
simulations of the formation of the LSS. Under the premise that the sources of
UHECRs are strongly associated with the LSS, we consider a model in which
protons with E >10^{19} eV are injected by sources that represent active
galactic nuclei located inside clusters of galaxies. With the model IGMFs, we
then follow the trajectories of the protons, while taking into account the
energy losses due to interactions with the cosmic background radiation. For
observers located inside groups of galaxies like ours, about 70% and 35% of
UHECR events above 60 EeV arrive within ~15 degree and ~5 degree, respectively,
of the source position with time delays of less than ~10^7 yr. This implies
that the arrival direction of super-GZK protons might exhibit a correlation
with the distribution of cosmological sources on the sky. In this model, nearby
sources (within 10 - 20 Mpc) should contribute significantly to the particle
flux above ~10^{20} eV.
| [
"astro-ph"
] | astro-ph | Astrophysics | 463Astrophysics
|
|
cond-mat/0601378 | We consider the tunneling Density of States (DoS) of superconducting films
driven to the paramagnetic phase by the Zeeman splitting. We show that there is
minimum in the DoS whose position depends on the orientation of the applied
field. This dependence, not predicted by previous theoretical calculations, is
in agreement with a recent experiment.
| [
"cond-mat.supr-con"
] | cond-mat.supr-con | Superconductivity | 7,066Superconductivity
|
|
2012.00491 | Contributing to the need of new graphene nanoribbon (GNR) structures that can
be synthesized with atomic precision, we have designed a reactant that renders
chiral (3,1) - GNRs after a multi-step reaction including Ullmann coupling and
cyclodehydrogenation. The nanoribbon synthesis has been successfully proved on
different coinage metals, and the formation process, together with the
fingerprints associated to each reaction step, has been studied combining
scanning tunnelling microscopy, core-level spectroscopy and density functional
calculations. In addition to the GNR chiral edge structure, the substantial GNR
lengths achieved and the low processing temperature required to complete the
reaction grant this reactant extremely interesting properties for potential
applications.
| [
"cond-mat.mtrl-sci"
] | cond-mat.mtrl-sci | Materials Science | 4,287Materials Science
|
|
2306.12829 | In the last decade, the need for storing videos from cataract surgery has
increased significantly. Hospitals continue to improve their imaging and
recording devices (e.g., microscopes and cameras used in microscopic surgery,
such as ophthalmology) to enhance their post-surgical processing efficiency.
The video recordings enable a lot of user-cases after the actual surgery, for
example, teaching, documentation, and forensics. However, videos recorded from
operations are typically stored in the internal archive without any
domain-specific compression, leading to a massive storage space consumption. In
this work, we propose a relevance-based compression scheme for videos from
cataract surgery, which is based on content specifics of particular cataract
surgery phases. We evaluate our compression scheme with three state-of-the-art
video codecs, namely H.264/AVC, H.265/HEVC, and AV1, and ask medical experts to
evaluate the visual quality of encoded videos. Our results show significant
savings, in particular up to 95.94% when using H.264/AVC, up to 98.71% when
using H.265/HEVC, and up to 98.82% when using AV1.
| [
"cs.MM"
] | cs.MM | Multimedia | 4,692Multimedia
|
|
1812.10114 | Photoemission driven by a strong electric field of near-infrared or visible
light, referred to as strong-field photoemission, produces attosecond electron
pulses that are synchronized to the waveform of the incident light, and this
principle lies at the heart of current attosecond technologies. However, full
access to strong-field photoemission regimes at near-infrared wavelengths based
on solid-state materials is restricted by space-charge screening and material
damage at high optical-field strengths, which significantly hampers the
realization of predicted attosecond technologies, such as ultra-sensitive
optical phase modulation. Here, we demonstrate a new type of strong-field
photoemission behaviour with extreme nonlinearity -- photoemission current
scales follow a 40th power law of the optical-field strength, making use of
sub-nanometric carbon nanotubes and 800 nm pulses. As a result, the total
photoemission current depends on the carrier-envelope phase with a greatly
improved photoemission current modulation depth of up to 100%, which has not
previously been achieved. Time-dependent density functional calculations reveal
the completely new behaviour of the optical-field induced tunnelling emission
process directly from the valence band of the carbon nanotubes, which is an
indication of full access to a strong-field photoemission regime. Furthermore,
the nonlinear dynamics are observed to be tunable by changing the binding
energy of the valence-band-maximum, as confirmed by Simpleman model
calculations. We believe that such extreme nonlinear photoemission from
nanotips offers a new means of producing extreme temporal-spatial resolved
electron pulses. These results additionally provide a new design philosophy for
attosecond electronics and optics by making use of tunable band structures in
nanomaterials.
| [
"physics.optics"
] | physics.optics | Optics | 5,146Optics
|
|
hep-th/9809198 | The existence of fluctuations together with interactions leads to
scale-dependence in the couplings of quantum field theories for the case of
quantum fluctuations, and in the couplings of stochastic systems when the
fluctuations are of thermal or statistical nature. In both cases the effects of
these fluctuations can be accounted for by solutions of the corresponding
renormalization group equations. We show how the renormalization group
equations are intimately connected with the effective action: given the
effective action we can extract the renormalization group equations; given the
renormalization group equations the effects of these fluctuations can be
included in the classical action by using what is known as improved
perturbation theory (wherein the bare parameters appearing in tree-level
expressions are replaced by their scale-dependent running forms). The improved
action can then be used to reconstruct the effective action, up to finite
renormalizations, and gradient terms.
| [
"hep-th"
] | hep-th | High Energy Physics - Theory | 3,266High Energy Physics - Theory
|
|
cs/0501043 | We advocate a declarative approach to proving properties of logic programs.
Total correctness can be separated into correctness, completeness and clean
termination; the latter includes non-floundering. Only clean termination
depends on the operational semantics, in particular on the selection rule. We
show how to deal with correctness and completeness in a declarative way,
treating programs only from the logical point of view. Specifications used in
this approach are interpretations (or theories). We point out that
specifications for correctness may differ from those for completeness, as
usually there are answers which are neither considered erroneous nor required
to be computed.
We present proof methods for correctness and completeness for definite
programs and generalize them to normal programs. For normal programs we use the
3-valued completion semantics; this is a standard semantics corresponding to
negation as finite failure. The proof methods employ solely the classical
2-valued logic. We use a 2-valued characterization of the 3-valued completion
semantics which may be of separate interest. The presented methods are compared
with an approach based on operational semantics. We also employ the ideas of
this work to generalize a known method of proving termination of normal
programs.
| [
"cs.LO",
"cs.PL"
] | cs.LO | cs.PL | Logic in Computer Science;Programming Languages | 3,842Logic in Computer Science;Programming Languages
|
1504.08265 | We present optimal online algorithms for two related known problems involving
Steiner Arborescence, improving both the lower and the upper bounds. One of
them is the well studied continuous problem of the {\em Rectilinear Steiner
Arborescence} ($RSA$). We improve the lower bound and the upper bound on the
competitive ratio for $RSA$ from $O(\log N)$ and $\Omega(\sqrt{\log N})$ to
$\Theta(\frac{\log N}{\log \log N})$, where $N$ is the number of Steiner
points. This separates the competitive ratios of $RSA$ and the Symetric-$RSA$,
two problems for which the bounds of Berman and Coulston is STOC 1997 were
identical. The second problem is one of the Multimedia Content Distribution
problems presented by Papadimitriou et al. in several papers and Charikar et
al. SODA 1998. It can be viewed as the discrete counterparts (or a network
counterpart) of $RSA$. For this second problem we present tight bounds also in
terms of the network size, in addition to presenting tight bounds in terms of
the number of Steiner points (the latter are similar to those we derived for
$RSA$).
| [
"cs.DS"
] | cs.DS | Data Structures and Algorithms | 1,908Data Structures and Algorithms
|
|
1808.05414 | Functional data analysis can be seriously impaired by abnormal observations,
which can be classified as either magnitude or shape outliers based on their
way of deviating from the bulk of data. Identifying magnitude outliers is
relatively easy, while detecting shape outliers is much more challenging. We
propose turning the shape outliers into magnitude outliers through data
transformation and detecting them using the functional boxplot. Besides easing
the detection procedure, applying several transformations sequentially provides
a reasonable taxonomy for the flagged outliers. A joint functional ranking,
which consists of several transformations, is also defined here. Simulation
studies are carried out to evaluate the performance of the proposed method
using different functional depth notions. Interesting results are obtained in
several practical applications.
| [
"stat.ME",
"stat.CO"
] | stat.ME | stat.CO | Methodology;Computation | 4,566Methodology;Computation
|
2010.05003 | In this paper, we propose second-order graph-based neural dependency parsing
using message passing and end-to-end neural networks. We empirically show that
our approaches match the accuracy of very recent state-of-the-art second-order
graph-based neural dependency parsers and have significantly faster speed in
both training and testing. We also empirically show the advantage of
second-order parsing over first-order parsing and observe that the usefulness
of the head-selection structured constraint vanishes when using BERT embedding.
| [
"cs.CL",
"cs.LG"
] | cs.CL | cs.LG | Computation and Language;Machine Learning | 1,237Computation and Language;Machine Learning
|
physics/0509107 | In this paper, we analyze the response of music and book sales to an external
field and to buyer herding. We distinguish endogenous and exogenous shocks. We
focus on some case studies, whose data have been collected from ranking on
amazon.com. We show that an ensemble of equivalent systems quantitatively
respond in a similar way to a similar ''external shock'', indicating roads to
universality features. In contrast to Sornette et al. [Phys. Rev. Lett. {93},
228701 (2004)] who seemed to find power law behaviors, in particular at long
times, - a law interpreted in terms of an epidemic activity, we observe that
the relaxation process can be as well seen as an exponential one that saturates
toward an asymptotic state, itself different from the pre-shock state. By
studying an ensemble of 111 shocks, on books or records, we show that exogenous
and endogenous shocks are discriminated by their short-time behaviour: the
relaxation time seems to be twice shorter in endogenous shocks than in
exogenous ones. We interpret the finding through a simple thermodynamic model
with a dissipative force.
| [
"physics.soc-ph"
] | physics.soc-ph | Physics and Society | 5,463Physics and Society
|
|
2208.13275 | This study proposes an end-to-end unsupervised diffeomorphic deformable
registration framework based on moving mesh parameterization. Using this
parameterization, a deformation field can be modeled with its transformation
Jacobian determinant and curl of end velocity field. The new model of the
deformation field has three important advantages; firstly, it relaxes the need
for an explicit regularization term and the corresponding weight in the cost
function. The smoothness is implicitly embedded in the solution which results
in a physically plausible deformation field. Secondly, it guarantees
diffeomorphism through explicit constraints applied to the transformation
Jacobian determinant to keep it positive. Finally, it is suitable for cardiac
data processing, since the nature of this parameterization is to define the
deformation field in terms of the radial and rotational components. The
effectiveness of the algorithm is investigated by evaluating the proposed
method on three different data sets including 2D and 3D cardiac MRI scans. The
results demonstrate that the proposed framework outperforms existing
learning-based and non-learning-based methods while generating diffeomorphic
transformations.
| [
"eess.IV",
"cs.CV",
"cs.LG"
] | eess.IV | cs.CV | Image and Video Processing;Computer Vision and Pattern Recognition;Machine Learning | 3,535Image and Video Processing;Computer Vision and Pattern Recognition;Machine Learning
|
cond-mat/0305311 | A model of carbon nanotube at half filling is studied. The Coulomb
interaction is assumed to be unscreened. It is shown that this allows to
develop the adiabatic approximation which leads to considerable simplifications
in calculations of the excitation spectrum. We give a detailed analysis of the
spectrum and the phase diagram at half filling and discuss effects of small
doping. At small doping several phases develop strong superconducting
fluctuations corresponding to various types of pairing.
| [
"cond-mat.str-el"
] | cond-mat.str-el | Strongly Correlated Electrons | 6,979Strongly Correlated Electrons
|
|
1908.05474 | Recently, a variety of regularization techniques have been widely applied in
deep neural networks, such as dropout, batch normalization, data augmentation,
and so on. These methods mainly focus on the regularization of weight
parameters to prevent overfitting effectively. In addition, label
regularization techniques such as label smoothing and label disturbance have
also been proposed with the motivation of adding a stochastic perturbation to
labels. In this paper, we propose a novel adaptive label regularization method,
which enables the neural network to learn from the erroneous experience and
update the optimal label representation online. On the other hand, compared
with knowledge distillation, which learns the correlation of categories using
teacher network, our proposed method requires only a minuscule increase in
parameters without cumbersome teacher network. Furthermore, we evaluate our
method on CIFAR-10/CIFAR-100/ImageNet datasets for image recognition tasks and
AGNews/Yahoo/Yelp-Full datasets for text classification tasks. The empirical
results show significant improvement under all experimental settings.
| [
"cs.LG",
"stat.ML"
] | cs.LG | stat.ML | Machine Learning;Machine Learning | 4,163Machine Learning;Machine Learning
|
2207.04222 | Fluctuations of dynamical quantities are fundamental and inevitable. For the
booming research in nanotechnology, huge relative fluctuation comes with the
reduction of system size, leading to large uncertainty for the estimates of
dynamical quantities. Thus, increasing statistical efficiency, i.e., reducing
the number of samples required to achieve a given accuracy, is of great
significance for accurate estimation. Here we propose a theory as a fundamental
solution for such problem by constructing auxiliary path for each real path.
The states on auxiliary paths constitute canonical ensemble and share the same
macroscopic properties with the initial states of the real path. By
implementing the theory in molecular dynamics simulations, we obtain a
nanoscale Couette flow field with an accuracy of 0.2 {\mu}m/s with relative
standard error < 0.1. The required number of samples is reduced by 12 orders
compared to conventional method. The predicted thermolubric behavior of water
sliding on a self-assembled surface is directly validated by experiment under
the same velocity. As the theory only assumes the system is initially in
thermal equilibrium then driven from that equilibrium by an external
perturbation, we believe it could serve as a general approach for extracting
the accurate estimate of dynamical quantities from large fluctuations to
provide insights on atomic level under experimental conditions, and benefit the
studies on mass transport across (biological) nanochannels and fluid film
lubrication of nanometer thickness.
| [
"stat.CO",
"physics.comp-ph",
"physics.flu-dyn"
] | stat.CO | physics.comp-ph | Computation;Computational Physics;Fluid Dynamics | 7,267longtail
|
1006.0488 | We present a simple estimate of the mass 'deficits' in cored spheroids, as a
function of galaxy mass and radius within the galaxy. Previous attempts to
measure such deficits depended on fitting some functional form to the profile
at large radii and extrapolating inwards; this is sensitive to the assumed
functional form and does not allow for variation in nuclear profile shapes. We
take advantage of larger data sets to directly construct stellar mass profiles
of observed systems and measure the stellar mass enclosed in a series of
physical radii (M(<R)), for samples of cusp and core spheroids at the same
stellar mass. There is a significant bimodality in this distribution at small
radii, and we non-parametrically measure the median offset between core and
cusp populations (the deficit Delta_M(<R)). We construct the scoured mass
profile as a function of radius, without reference to any assumed functional
form. The mass deficit rises in power-law fashion (Delta_M(<R) R^{1.3-1.8})
from a significant but small mass at R<10pc, to asymptote to a maximum ~0.5-2
M_BH at ~100pc. At larger radii there is no statistically significant
separation between populations; the upper limit to the cumulative scoured mass
at ~kpc is ~2-4 M_BH. This does not depend strongly on stellar mass. The
dispersion in M(<R) appears larger in the core population, possibly reflecting
the fact that scouring increases the scatter in profile shapes. These results
are in good agreement with models of scouring from BH binary systems.
| [
"astro-ph.CO",
"astro-ph.GA",
"astro-ph.HE"
] | astro-ph.CO | astro-ph.GA | Cosmology and Nongalactic Astrophysics;Astrophysics of Galaxies;High Energy Astrophysical Phenomena | 1,732Cosmology and Nongalactic Astrophysics;Astrophysics of Galaxies;High Energy Astrophysical Phenomena
|
1411.0133 | The Z(N) dependence of the pure Yang-Mills gluon propagator, in the Landau
gauge, is investigated at finite temperature for N=3. Special attention will be
given to the behaviour near the critical temperature $T_c$. Our simulations
show a complex pattern as expected in a first order phase transition.
Furthermore, we identify an order parameter directly associated with the
breaking of the SU(3) center symmetry.
| [
"hep-lat"
] | hep-lat | High Energy Physics - Lattice | 3,092High Energy Physics - Lattice
|
|
0906.2086 | We prove an equivalence result between the validity of a pointwise Hardy
inequality in a domain and uniform capacity density of the complement. This
result is new even in Euclidean spaces, but our methods apply in general metric
spaces as well. We also present a new transparent proof for the fact that
uniform capacity density implies the classical integral version of the Hardy
inequality in the setting of metric spaces. In addition, we consider the
relations between the above concepts and certain Hausdorff content conditions.
| [
"math.AP"
] | math.AP | Analysis of PDEs | 205Analysis of PDEs
|
|
1809.04807 | When a high dimension system of ordinary differential equations is solved
numerically, the computer memory capacity may be compromised. Thus, for such
systems, it is important to incorporate low memory usage to some other
properties of the scheme. In the context of strong stability preserving (SSP)
schemes, some low-storage methods have been considered in the literature. In
this paper we study 5-stage third order 2N* low-storage SSP explicit
Runge-Kutta schemes. These are SSP schemes that can be implemented with 2N
memory registers, where N is the dimension of the problem, and retain the
previous time step approximation. This last property is crucial for a variable
step size implementation of the scheme. In this paper, first we show that the
optimal SSP methods cannot be implemented with 2N* memory registers. Next, two
non-optimal SSP 2N* low-storage methods are constructed; although their SSP
coefficients are not optimal, they achieve some other interesting properties.
Finally, we show some numerical experiments.
| [
"math.NA"
] | math.NA | Numerical Analysis | 5,002Numerical Analysis
|
|
2207.06010 | Extracting informative representations of molecules using Graph neural
networks (GNNs) is crucial in AI-driven drug discovery. Recently, the graph
research community has been trying to replicate the success of self-supervised
pretraining in natural language processing, with several successes claimed.
However, we find the benefit brought by self-supervised pretraining on small
molecular data can be negligible in many cases. We conduct thorough ablation
studies on the key components of GNN pretraining, including pretraining
objectives, data splitting methods, input features, pretraining dataset scales,
and GNN architectures, to see how they affect the accuracy of the downstream
tasks. Our first important finding is, self-supervised graph pretraining do not
always have statistically significant advantages over non-pretraining methods
in many settings. Secondly, although noticeable improvement can be observed
with additional supervised pretraining, the improvement may diminish with
richer features or more balanced data splits. Thirdly, hyper-parameters could
have larger impacts on accuracy of downstream tasks than the choice of
pretraining tasks, especially when the scales of downstream tasks are small.
Finally, we provide our conjectures where the complexity of some pretraining
methods on small molecules might be insufficient, followed by empirical
evidences on different pretraining datasets.
| [
"cs.LG",
"q-bio.BM"
] | cs.LG | q-bio.BM | Machine Learning;Biomolecules | 3,998Machine Learning;Biomolecules
|
2201.06282 | In contrast to SPD matrices, few tools exist to perform Riemannian statistics
on the open elliptope of full-rank correlation matrices. The quotient-affine
metric was recently built as the quotient of the affine-invariant metric by the
congruence action of positive diagonal matrices. The space of SPD matrices had
always been thought of as a Riemannian homogeneous space. In contrast, we view
in this work SPD matrices as a Lie group and the affine-invariant metric as a
left-invariant metric. This unexpected new viewpoint allows us to generalize
the construction of the quotient-affine metric and to show that the main
Riemannian operations can be computed numerically. However, the uniqueness of
the Riemannian logarithm or the Fr{\'e}chet mean are not ensured, which is bad
for computing on the elliptope. Hence, we define three new families of
Riemannian metrics on full-rank correlation matrices which provide Hadamard
structures, including two flat. Thus the Riemannian logarithm and the
Fr{\'e}chet mean are unique. We also define a nilpotent group structure for
which the affine logarithm and the group mean are unique. We provide the main
Riemannian/group operations of these four structures in closed form.
| [
"math.DG"
] | math.DG | Differential Geometry | 2,010Differential Geometry
|
|
2004.00697 | A dynamical aspect of quantum gravity on de Sitter spacetime is investigated
by holography or the dS/CFT correspondence. We show that de Sitter spacetime
emerges from a free Sp(N) vector model by complexifying the ghost fields and
flowing them in parallel to the imaginary axis. We confirm that the emergence
of de Sitter spacetime is ensured by conformal symmetry. We also compute the
quantum corrections to the cosmological constant up to the next-to-leading
order of the 1/N expansion in a proposed holographic approach. As a result the
sub-leading corrections have the opposite sign to the classical value.This
implies that a quantum gravity on de Sitter spacetime is perturbatively stable
and quantum effects make the universe flatter and the cosmological constant
smaller.
| [
"hep-th",
"gr-qc",
"hep-lat",
"hep-ph"
] | hep-th | gr-qc | High Energy Physics - Theory;General Relativity and Quantum Cosmology;High Energy Physics - Lattice;High Energy Physics - Phenomenology | 3,327High Energy Physics - Theory;General Relativity and Quantum Cosmology;High Energy Physics - Lattice;High Energy Physics - Phenomenology
|
1208.3333 | In recent research it was found that the fundamental shear-localizing
instability of amorphous solids under external strain, which eventually results
in a shear band and failure, consists of a highly correlated array of Eshelby
quadrupoles all having the same orientation and some density $\rho$. In this
paper we calculate analytically the energy $E(\rho,\gamma)$ associated with
such highly correlated structures as a function of the density $\rho$ and the
external strain $\gamma$. We show that for strains smaller than a
characteristic strain $\gamma_Y$ the total strain energy initially increases as
the quadrupole density increases, but that for strains larger than $\gamma_Y$
the energy monotonically decreases with quadrupole density. We identify
$\gamma_Y$ as the yield strain. Its value, derived from values of the qudrupole
strength based on the atomistic model, agrees with that from the computed
stress-strain curves and broadly with experimental results.
| [
"cond-mat.soft"
] | cond-mat.soft | Soft Condensed Matter | 6,537Soft Condensed Matter
|
|
1407.0125 | During this work, using subtraction renormalization mechanism, zero point
quantum fluctuations for bosonic scalar fields in a de-Sitter like background
are investigated. By virtue of the observed value for spectral index, $n_s(k)$,
for massive scalar field the best value for the first slow roll parameter,
$\epsilon$, is achieved. In addition the energy density of vacuum quantum
fluctuations for massless scalar field is obtained. The effects of these
fluctuations on other components of the Universe are studied. By solving the
conservation equation, for some different examples, the energy density for
different components of the Universe are obtained. In the case which, all
components of the Universe are in an interaction, the different dissipation
functions, $\tilde{Q}_{i}$, are considered. The time evolution of
${\rho_{DE}(z)}/{\rho_{cri}(z)}$ shows that $\tilde{Q}=3 \gamma H(t) \rho_{m}$
has best agreement in comparison to observational data including CMB, BAO and
SNeIa data set.
| [
"gr-qc"
] | gr-qc | General Relativity and Quantum Cosmology | 2,674General Relativity and Quantum Cosmology
|
|
1406.7532 | Xclaim (x-ray core level atomic multiplets) is a graphical interface for the
calculation of core-hole spectroscopy and ground state properties within a
charge-transfer multiplet model taking into account a many-body hamiltonian
with Coulomb, spin-orbit, crystal-field, and hybridization interactions. Using
Hartree-Fock estimates for the Coulomb and spin-orbit interactions and ligand
field parameters (crystal-field, hybridization and charge-transfer energy) the
program can calculate x-ray absorption spectroscopy (XAS), x-ray photoemission
spectroscopy (XPS), photoemission spectrospcy (PES) and inverse photoemission
(IPES) for d- and f-valence metals and different absorption edges. The program
runs in Linux, Windows and MacOS platforms.
| [
"cond-mat.str-el"
] | cond-mat.str-el | Strongly Correlated Electrons | 6,979Strongly Correlated Electrons
|
|
2307.09139 | We report the synthesis of transition-metal-doped ferromagnetic elemental
single-crystal semiconductors with quantum oscillations using the physical
vapor transport method. The 7.7 atom% Cr-doped Te crystals (Cr_Te) show
ferromagnetism, butterfly-like negative magnetoresistance in the low
temperature (< 3.8 K) and low field (< 0.15 T) region, and high Hall mobility,
e.g., 1320 cm2 V-1 s-1 at 30 K and 350 cm2 V-1 s-1 at 300 K, implying that
Cr_Te crystals are ferromagnetic elemental semiconductors. When B // c // I,
the maximum negative MR is -27% at T = 20 K and B = 8 T. In the low temperature
semiconducting region, Cr_Te crystals show strong discrete scale invariance
dominated logarithmic quantum oscillations when the direction of the magnetic
field B is parallel to the [100] crystallographic direction and show Landau
quantization dominated Shubnikov-de Haas (SdH) oscillations for B // [210]
direction, which suggests the broken rotation symmetry of the Fermi pockets in
the Cr_Te crystals. The findings of coexistence of multiple quantum
oscillations and ferromagnetism in such an elemental quantum material may
inspire more study of narrow bandgap semiconductors with ferromagnetism and
quantum phenomena.
| [
"cond-mat.mtrl-sci"
] | cond-mat.mtrl-sci | Materials Science | 4,287Materials Science
|
|
2008.07466 | We propose a method for controlled narrative/story generation where we are
able to guide the model to produce coherent narratives with user-specified
target endings by interpolation: for example, we are told that Jim went hiking
and at the end Jim needed to be rescued, and we want the model to incrementally
generate steps along the way. The core of our method is an interpolation model
based on GPT-2 which conditions on a previous sentence and a next sentence in a
narrative and fills in the gap. Additionally, a reranker helps control for
coherence of the generated text. With human evaluation, we show that
ending-guided generation results in narratives which are coherent, faithful to
the given ending guide, and require less manual effort on the part of the human
guide writer than past approaches.
| [
"cs.CL"
] | cs.CL | Computation and Language | 1,168Computation and Language
|
|
0807.2036 | Fermionic mean-field theory and variational Monte Carlo calculations are
employed to shed light on the possible uniform ground states of the Heisenberg
model on the pyrochlore lattice. Among the various flux configurations, we find
the chiral spin states carrying \pm pi/2 flux through each triangular face to
be the most stable both within the mean-field theory and the projected
wave-function studies. Properties of the spin-spin correlation function and the
chirality order parameter are calculated for the projected wave functions.
Mean-field band structures are examined.
| [
"cond-mat.str-el"
] | cond-mat.str-el | Strongly Correlated Electrons | 6,979Strongly Correlated Electrons
|
|
1209.3444 | We compare deformations of algebras to deformations of schemes in the setting
of invariant theory. Our results generalize comparison theorems of Schlessinger
and the second author for projective schemes. We consider deformations
(abstract and embedded) of a scheme $X$ which is a good quotient of a
quasi-affine scheme $X^\prime$ by a linearly reductive group $G$ and compare
them to invariant deformations of an affine $G$-scheme containing $X^\prime$ as
an open invariant subset. The main theorems give conditions for when the
comparison morphisms are smooth or isomorphisms.
| [
"math.AG"
] | math.AG | Algebraic Geometry | 47Algebraic Geometry
|
|
1901.00795 | We propose to model mortality hazard rates for human population using the
exponential of the solution of a stochastic differential equation (SDE). The
noise in the SDE is a fractional Brownian motion. We will use the well-known
fractional Ornstein-Uhlenbeck process. Using the Hurst parameter we showed that
mortality rates exhibit long-term memory. The proposed model is a
generalization of the model introduced by [6], where they used an SDE driven
with a Brownian motion. We tested our model with the Italian population between
the years 1950 to 2004.
| [
"math.PR",
"stat.AP"
] | math.PR | stat.AP | Probability;Applications | 5,720Probability;Applications
|
1203.3482 | Computing the probability of a formula given the probabilities or weights
associated with other formulas is a natural extension of logical inference to
the probabilistic setting. Surprisingly, this problem has received little
attention in the literature to date, particularly considering that it includes
many standard inference problems as special cases. In this paper, we propose
two algorithms for this problem: formula decomposition and conditioning, which
is an exact method, and formula importance sampling, which is an approximate
method. The latter is, to our knowledge, the first application of model
counting to approximate probabilistic inference. Unlike conventional
variable-based algorithms, our algorithms work in the dual realm of logical
formulas. Theoretically, we show that our algorithms can greatly improve
efficiency by exploiting the structural information in the formulas.
Empirically, we show that they are indeed quite powerful, often achieving
substantial performance gains over state-of-the-art schemes.
| [
"cs.AI"
] | cs.AI | Artificial Intelligence | 361Artificial Intelligence
|
|
1601.01576 | Social structures emerge as a result of individuals managing a variety of
different of social relationships. Societies can be represented as highly
structured dynamic multiplex networks. Here we study the dynamical origins of
the specific community structures of a large-scale social multiplex network of
a human society that interacts in a virtual world of a massive multiplayer
online game. There we find substantial differences in the community structures
of different social actions, represented by the various network layers in the
multiplex. Community size distributions are either similar to a power-law or
appear to be centered around a size of 50 individuals. To understand these
observations we propose a voter model that is built around the principle of
triadic closure. It explicitly models the co-evolution of node- and
link-dynamics across different layers of the multiplex. Depending on link- and
node fluctuation rates, the model exhibits an anomalous shattered fragmentation
transition, where one layer fragments from one large component into many small
components. The observed community size distributions are in good agreement
with the predicted fragmentation in the model. We show that the empirical
pairwise similarities of network layers, in terms of link overlap and degree
correlations, practically coincide with the model. This suggests that several
detailed features of the fragmentation in societies can be traced back to the
triadic closure processes.
| [
"physics.soc-ph",
"cond-mat.stat-mech",
"cs.SI"
] | physics.soc-ph | cond-mat.stat-mech | Physics and Society;Statistical Mechanics;Social and Information Networks | 5,548Physics and Society;Statistical Mechanics;Social and Information Networks
|
0802.3213 | The fundamental properties of stellar clusters, such as the age or the total
initial mass in stars, are often inferred from population synthesis models. The
predicted properties are then used to constrain the physical mechanisms
involved in the formation of such clusters in a variety of environments.
Population synthesis models cannot, however, be applied blindy to such systems.
We show that synthesis models cannot be used in the usual straightforward way
to small-mass clusters (say, M < few times 10**4 Mo). The reason is that the
basic hypothesis underlying population synthesis (a fixed proportionality
between the number of stars in the different evolutionary phases) is not
fulfilled in these clusters due to their small number of stars. This incomplete
sampling of the stellar mass function results in a non-gaussian distribution of
the mass-luminosity ratio for clusters that share the same evolutionary
conditions (age, metallicity and initial stellar mass distribution function).
We review some tests that can be carried out a priori to check whether a given
cluster can be analysed with the fully-sampled standard population synthesis
models, or, on the contrary, a probabilistic framework must be used. This leads
to a re-assessment in the estimation of the low-mass tail in the distribution
function of initial masses of stellar clusters.
| [
"astro-ph"
] | astro-ph | Astrophysics | 463Astrophysics
|
|
1907.07279 | This paper addresses the problem of target detection and localisation in a
limited area using multiple coordinated agents. The swarm of Unmanned Aerial
Vehicles (UAVs) determines the position of the dispersion of stack effluents to
a gas plume in a certain production area as fast as possible, that makes the
problem challenging to model and solve, because of the time variability of the
target. Three different exploration algorithms are designed and compared.
Besides the exploration strategies, the paper reports a solution for quick
convergence towards the actual stack position once detected by one member of
the team. Both the navigation and localisation algorithms are fully distributed
and based on the consensus theory. Simulations on realistic case studies are
reported.
| [
"cs.RO",
"cs.DC"
] | cs.RO | cs.DC | Robotics;Distributed, Parallel, and Cluster Computing | 6,369Robotics;Distributed, Parallel, and Cluster Computing
|
2303.04273 | As some of the most compact stellar objects in the universe, neutron stars
are unique cosmic laboratories. The study of neutron stars provides an ideal
theoretical testbed for investigating both physics at supra-nuclear densities
as well as fundamental physics. Their global astrophysical properties however
depend strongly on the star's internal structure, which is currently unknown
due to uncertainties in the equation of state. In recent years, a lot of work
has revealed the existence of universal relations between stellar quantities
that are insensitive to the equation of state. At the same time, the fields of
multimessenger astronomy and machine learning have both advanced significantly.
As such, there has been a confluence of research into their combination and the
field is growing. In this paper, we develop universal relations for rapidly
rotating neutron stars, by using supervised machine learning methods, thus
proposing a new way of discovering and validating such relations. The analysis
is performed for tabulated hadronic, hyperonic, and hybrid EoS-ensembles that
obey the multimessenger constraints and cover a wide range of stiffnesses. The
relations discussed could provide an accurate tool to constrain the equation of
state of nuclear matter when measurements of the relevant observables become
available.
| [
"astro-ph.HE",
"gr-qc"
] | astro-ph.HE | gr-qc | High Energy Astrophysical Phenomena;General Relativity and Quantum Cosmology | 3,022High Energy Astrophysical Phenomena;General Relativity and Quantum Cosmology
|
1707.04523 | The realization of Dirac and Weyl physics in solids has made topological
materials one of the main focuses of condensed matter physics. Recently, the
topic of topological nodal line semimetals, materials in which Dirac or
Weyl-like crossings along special lines in momentum space create either a
closed ring or line of degeneracies, rather than discrete points, has become a
hot topic in topological quantum matter. Here we review the experimentally
confirmed and theoretically predicted topological nodal line semimetals,
focusing in particular on the symmetry protection mechanisms of the nodal lines
in various materials. Three different mechanisms: a combination of inversion
and time-reversal symmetry, mirror reflection symmetry, and non-symmorphic
symmetry, and their robustness under the effect of spin orbit coupling are
discussed. We also present a new Weyl nodal line material, the Te-square net
compound KCu$_2$EuTe$_4$, which has several Weyl nodal lines including one
extremely close to the Fermi level ($<$30 meV below E$_F$). Finally, we discuss
potential experimental signatures for observing exotic properties of nodal line
physics.
| [
"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
|
1407.2344 | In this paper, we study the Cauchy problem of the Euler-Nernst-Planck-Possion
system. We obtain global well-posedness for the system in dimension $d=2$ for
any initial data in $H^{s_1}(\mathbb{R}^2)\times H^{s_2}(\mathbb{R}^2)\times
H^{s_2}(\mathbb{R}^2)$ under certain conditions of $s_1$ and $s_2$.
| [
"math.AP"
] | math.AP | Analysis of PDEs | 205Analysis of PDEs
|
|
cond-mat/0109083 | We obtain the exact position of the percolation threshold in intentionally
damaged scale-free networks.
| [
"cond-mat.stat-mech"
] | cond-mat.stat-mech | Statistical Mechanics | 6,821Statistical Mechanics
|
|
2012.10262 | We show that filling an order with a large number of distinct counterparts
incurs additional market impact, as opposed to filling the order with a small
number of counterparts. For best execution, therefore, it may be beneficial to
opportunistically fill orders with as few counterparts as possible in
Large-in-scale (LIS) venues.
This article introduces the concept of concentrated trading, a situation that
occurs when a large fraction of buying or selling in a given time period is
done by one or a few traders, for example when executing a large order. Using
London Stock Exchange data, we show that concentrated trading suffers price
impact in addition to impact caused by (smart) order routing. However, when
matched with similarly concentrated counterparts on the other side of the
market, the impact is greatly reduced. This suggests that exposing an order on
LIS venues is expected to result in execution performance improvement.
| [
"q-fin.TR"
] | q-fin.TR | Trading and Market Microstructure | 7,254Trading and Market Microstructure
|
|
2110.06133 | Topline hotels are now shifting into the digital way in how they understand
their customers to maintain and ensuring satisfaction. Rather than the
conventional way which uses written reviews or interviews, the hotel is now
heavily investing in Artificial Intelligence particularly Machine Learning
solutions. Analysis of online customer reviews changes the way companies make
decisions in a more effective way than using conventional analysis. The purpose
of this research is to measure hotel service quality. The proposed approach
emphasizes service quality dimensions reviews of the top-5 luxury hotel in
Indonesia that appear on the online travel site TripAdvisor based on section
Best of 2018. In this research, we use a model based on a simple Bayesian
classifier to classify each customer review into one of the service quality
dimensions. Our model was able to separate each classification properly by
accuracy, kappa, recall, precision, and F-measure measurements. To uncover
latent topics in the customer's opinion we use Topic Modeling. We found that
the common issue that occurs is about responsiveness as it got the lowest
percentage compared to others. Our research provides a faster outlook of hotel
rank based on service quality to end customers based on a summary of the
previous online review.
| [
"cs.IR",
"cs.SI",
"econ.GN",
"q-fin.EC"
] | cs.IR | cs.SI | Information Retrieval;Social and Information Networks;General Economics;Economics | 7,267longtail
|
2110.02023 | We study the effect on the parton distribution functions (PDFs) from the
inclusion of projected measurements in the Drell-Yan (DY) di-lepton production
neutral channel of the angular coefficient associated to the $Z$-boson
longitudinal polarisation. The pseudodata, generated assuming two luminosity
scenarios, is employed for the profiling of existing PDF sets using the
open-source platform xFitter. We find the observable particularly relevant in
constraining the gluon PDF, which in turn translates into a reduction of the
systematic uncertainties of the Standard Model (SM) Higgs boson production
cross section.
| [
"hep-ph"
] | hep-ph | High Energy Physics - Phenomenology | 3,129High Energy Physics - Phenomenology
|
|
2302.06145 | The modified Langevin noise formalism has been proposed for the correct
charaterization of quantum electromagnetic fields in the presence of
finite-sized lossy dielectric objects in free space. The main modification to
the original one (also known as the Green's function approach available only
for bulk inhomogeneous lossy dielectric medium) was to add fluctuating sources
in reaction to the radiation loss. Consequently, a resulting electric field
operator is now determined by (i) boundary-assisted and (ii) medium-assisted
fields on an equal footing, which are fluctuating sources due to radiation and
medium losses, respectively. However, due to the lengthy mathematical
manipulation and complicated concepts, the validity of the modified Langevin
noise formalism has not been clearly checked yet.
In this work, we propose and develop a novel numerical framework for the
modified Langevin noise formalism by exploiting computational electromagnetic
methods (CEM). Specifically, we utilize the finite-element method to
numerically solve plane-wave-scattering and point-source-radiation problems
whose solutions are boundary-assisted and medium-assisted fields, respectively.
Based on the developed numerical framework, we calculate the Purcell factor of
a two-level atom inside or outside a lossy dielectric slab. It is numerically
proved, for the first time, that one can retrieve the conventional expression
of the spontaneous emission rate, viz., the imaginary part of the Green's
function.
The proposed numerical framework is particularly useful for estimating the
dynamics of multi-level atoms near practical plasmonic structures or
metasurfaces.
| [
"quant-ph"
] | quant-ph | Quantum Physics | 5,985Quantum Physics
|
|
1705.03189 | Every Serre subcategory of an abelian category is assigned a unique type. The
type of a Serre subcategory of a Grothendieck category is in the list: $$(0,
0), \ (0, -1), \ (1, -1), \ (0, -2), \ (1, -2), \ (2, -1), \ (+\infty,
-\infty);$$ and for each $(m, -n)$ in this list, there exists a Serre
subcategory such that its type is $(m, -n)$. This uses right (left)
recollements of abelian categories, Tachikawa-Ohtake [TO] on strongly
hereditary torsion pairs, and Geigle-Lenzing [GL] on localizing subcategories.
If all the functors in a recollement of abelian categories are exact, then the
recollement splits. Quite surprising, any left recollement of a Grothendieck
category can be extended to a recollement; but this is not true for a right
recollement. Thus, a colocalizing subcategory of a Grothendieck category is
localizing; but the converse is not true. All these results do not hold in
triangulated categories.
| [
"math.CT"
] | math.CT | Category Theory | 757Category Theory
|
|
2102.10151 | The increasing number of Photovoltaic (PV) systems connected to the power
grid are vulnerable to the projection of shadows from moving clouds. Global
Solar Irradiance (GSI) forecasting allows smart grids to optimize the energy
dispatch, preventing energy shortages caused by occlusion of the sun. This
investigation compares the performances of machine learning algorithms (not
requiring labelled images for training) for real-time segmentation of clouds in
images acquired using a ground-based infrared sky imager. Real-time
segmentation is utilized to extract cloud features using only the pixels in
which clouds are detected.
| [
"eess.IV"
] | eess.IV | Image and Video Processing | 3,521Image and Video Processing
|
|
0902.1844 | The nuclear chosmochronometer suggested by Hayakawa et al. [Phys. Rev.C 77,
065802 (2008)] based on the 138La-138Ce-136Ce abundance ratio in presolar
grains would be affected by the existence of a hitherto unknown low-energy 1+
state in 138La. Results of a recent high-resolution study of the 138Ba(3He,t)
reaction under kinematics selectively populating 1+ states in 138La through
Gamow-Teller transitions provides strong evidence against the existence of such
a hypothetical state.
| [
"astro-ph.SR",
"nucl-ex"
] | astro-ph.SR | nucl-ex | Solar and Stellar Astrophysics;Nuclear Experiment | 6,718Solar and Stellar Astrophysics;Nuclear Experiment
|
2012.13526 | The extended scalar-tensor and vector-tensor theories admit black hole
solutions with the nontrivial profiles of the scalar and vector fields,
respectively. The disformal transformation maps a solution in a class of the
scalar-tensor or vector-tensor theories to that in another class, and hence it
can be a useful tool to construct a new nontrivial solution from the known one.
First, we investigate how the stationary and axisymmetric solutions in the
vector-tensor theories without and with the $U(1)$ gauge symmetry are
disformally transformed. We start from a stationary and axisymmetric solution
satisfying the circularity conditions, and show that in both the cases the
metric of the disformed solution in general does not satisfy the circularity
conditions. Using the fact that a solution in a class of the vector-tensor
theories with the vanishing field strength is mapped to that in a class of the
shift-symmetric scalar-tensor theories, we derive the disformed stationary and
axisymmetric solutions in a class of these theories, and show that the metric
of the disformed solutions does not satisfy the circularity conditions if the
scalar field depends on the time or azimuthal coordinate. We also confirm that
in the scalar-tensor theories without the shift symmetry, the disformed
stationary and axisymmetric solutions satisfy the circularity conditions.
Second, we investigate the disformal transformations of the stationary and
axisymmetric black hole solutions in the generalized Proca theory with the
nonminimal coupling to the Einstein tensor, the shift-symmetric scalar-tensor
theory with the nonminimal derivative coupling to the Einstein tensor, the
Einstein-Maxwell theory, and the Einstein-conformally coupled scalar field
theory. We show that the disformal transformations modify the causal properties
of the spacetime.
| [
"gr-qc"
] | gr-qc | General Relativity and Quantum Cosmology | 2,674General Relativity and Quantum Cosmology
|
|
2205.11741 | Since it is difficult to apply the existing method of friction and heat flux
decomposition on the complex surface, a combined decomposition method of
friction and heat flux with clear physical interpretation is proposed, which is
based on FIK and RD decomposition method and can be applied to arbitrary
surface. Based on this method, the aerothermodynamic characteristics of
bistable states of curved compression ramps are analyzed from the perspective
of energy transformation. The results show that the decrease of friction in the
interaction region of the attachment state and the minimum values of friction
in the separation bubble are all caused by the energy injection of the work by
the adverse pressure gradient. The peak friction is mainly induced by the
viscous dissipation, and its position is affected by the mechanical energy
transport. The peak heat flux is mainly induced by viscous dissipation, and the
enthalpy transport of the separation state plays a greater role in the peak
heat flux generation than that of the attachment state. These results indicate
that reducing viscous dissipation is a potential way for realizing friction and
heat flux control simultaneously.
| [
"physics.flu-dyn"
] | physics.flu-dyn | Fluid Dynamics | 2,452Fluid Dynamics
|
|
1001.5060 | The class of type Ic supernovae have drawn increasing attention since 1998
owing to their sparse association (only four so far) with long duration
gamma-ray bursts. Although both phenomena originate from the core collapse of a
massive star, supernovae emit mostly at optical wavelengths, whereas GRBs emit
mostly in soft gamma-rays or hard X-rays. Though the GRB central engine
generates ultra-relativistic jets, which beam the early emission into a narrow
cone, no relativistic outflows have hitherto been found in type Ib/c supernovae
explosions, despite theoretical expectations and searches. Here we report radio
(interferometric) observations that reveal a mildly relativistic expansion in a
nearby type Ic supernova, SN 2007gr. Using two observational epochs 60 days
apart, we detect expansion of the source and establish a conservative lower
limit for the average apparent expansion velocity of 0.6c. Independently, a
second mildly relativistic supernova has been reported. Contrary to the radio
data, optical observations of SN 2007gr indicate a typical type Ic supernova
with ejecta velocities ~6000 km/s, much lower than in GRB-associated
supernovae. We conclude that in SN 2007gr a small fraction of the ejecta
produced a low-energy mildly relativistic bipolar radio jet, while the bulk of
the ejecta were slower and, as shown by optical spectro-polarimetry, mildly
aspherical.
| [
"astro-ph.HE"
] | astro-ph.HE | High Energy Astrophysical Phenomena | 2,990High Energy Astrophysical Phenomena
|
|
2012.05813 | We study the local limits of uniform high genus bipartite maps with
prescribed face degrees. We prove the convergence towards a family of infinite
maps of the plane, the q-IBPMs, which exhibit both a spatial Markov property
and a hyperbolic behaviour. Therefore, we observe a similar local behaviour for
a wide class of models of random high genus maps, which can be seen as a result
of universality. Our results cover all the regimes where the expected degree of
the root face remains finite in the limit. This follows a work by the same
authors on high genus triangulations arXiv:1902.00492.
| [
"math.PR",
"math.CO"
] | math.PR | math.CO | Probability;Combinatorics | 5,726Probability;Combinatorics
|
2307.06336 | Recent compilations of NIRSpec emission line galaxies have shown a mild
redshift evolution of the FMR at $z > 4$, indicating that the FMR alone is not
fully capable of capturing the redshift evolution of the mass-metallicity
relation: $z > 4$ galaxies appear more metal-poor than the FMR predictions.
There is evidence that the most metal-deficient high-redshift galaxies are also
the most compact. In this work, we further investigate this anti-correlation by
leveraging the wealth of data gathered through the first cycle of JWST. We
compile a sample of 427 $z > 3$ galaxies covered by both the NIRSpec prism and
NIRCam short-wavelength photometry, consisting of 334 galaxies from the
publicly available programs and 93 galaxies from the first data release of the
JADES program. We use this sample to infer the redshift evolution of the FMR
from $z = 3$ to $z \sim 10$, further confirming the previously reported mild
redshift evolution. We measure the rest-ultraviolet (UV) sizes of $z > 4$
galaxies, inferring the mass-size relation at $z = 4-10$ with a power-law slope
of $0.21 \pm 0.04$. We investigate the redshift evolution of the mass-size
relation, finding that at a fixed stellar mass, higher redshift galaxies appear
more compact. The degree of this redshift evolution depends on the stellar
mass, with the lowest mass galaxies showing the strongest redshift evolution
and the most massive galaxies ($\log(M_{\star}/M_{\odot}) > 9$) showing no
redshift evolution. We investigate the anti-correlation between the compactness
of galaxies and their gas-phase metallicities, finding that the more compact
galaxies appear more metal-deficient and therefore more offset from the local
calibration of the FMR. (abridged)
| [
"astro-ph.GA"
] | astro-ph.GA | Astrophysics of Galaxies | 464Astrophysics of Galaxies
|
|
1108.5382 | A significant fraction of unstable multiple planet systems likely scatter
during the transitional disc phase as gas damping becomes ineffectual. Using an
ensemble of FARGO hydrodynamic simulations and MERCURY n-body integrations, we
directly follow planet-disc and planet-planet interactions through the clearing
phase and on through 50 Myr of dynamical evolution. Disc clearing occurs via
X-ray driven photoevaporation. The hydrodynamic evolution of individual
scattering systems is complex, and involves phases in which massive planets
orbit within eccentric gaps, or accrete directly from the disc without a gap.
Comparing the results to a gas-free model, we find that the n-body dynamics and
hydrodynamics of scattering into one- and two-planet final states are almost
identical. The eccentricity distributions in these channels are almost
unaltered by the presence of gas. The hydrodynamic simulations, however, also
form low eccentricity three-planet systems in long-term stable configurations,
and the admixture of these systems results in modestly lower eccentricities in
hydrodynamic as opposed to gas-free simulations. The incidence of these
three-planet systems is likely a function of the initial conditions; different
planet setups (number or spacing) may change the character of this result. We
analyze the properties of surviving multiple planet systems, and show that only
a small fraction (a few percent) enter mean-motion resonances after scattering,
while a larger fraction form stable resonant chains and avoid scattering
entirely. Our results remain consistent with the hypothesis that exoplanet
eccentricity results from scattering, though the detailed agreement between
observations and gas-free simulation results is likely coincidental. We discuss
the prospects for testing scattering models by observing planets or
non-axisymmetric gas structure in transitional discs.
| [
"astro-ph.EP",
"astro-ph.SR"
] | astro-ph.EP | astro-ph.SR | Earth and Planetary Astrophysics;Solar and Stellar Astrophysics | 2,390Earth and Planetary Astrophysics;Solar and Stellar Astrophysics
|
1110.1812 | We study properties of Wigner crystal in snaked nanochannels and show that
they are characterized by a conducting sliding phase at low charge densities
and an insulating pinned phase emerging above a certain critical charge
density. We trace parallels between this model problem and the Little
suggestion for electron transport in organic molecules. We also show that in
presence of periodic potential inside the snaked channel the sliding phase
exists only inside a certain window of electron densities that has similarities
with a pressure dependence of conductivity in organic conductors. Our studies
show emergence of dynamical glassy phase in a purely periodic potential in
absence of any disorder that can explain enormously slow variations of
resistivity in organic conductors. Finally we discuss the KAM concept of
superfluidity induced by repulsive Coulomb interaction between electrons. We
argue that the transition from the sliding KAM phase to the pinned Aubry phase
corresponds to the superfluid-insulator transition.
| [
"cond-mat.str-el"
] | cond-mat.str-el | Strongly Correlated Electrons | 6,979Strongly Correlated Electrons
|
|
1605.05177 | Using femtosecond time- and angle-resolved photoemission spectroscopy we
investigate the effect of electron doping on the electron dynamics in
Ba(Fe_{1-x}Co_x)_2As_2 in a range of 0 < x < 0.15 at temperatures slightly
above the N\'eel temperature. By analyzing the time-dependent photoemission
intensity of the pump laser excited population as a function of energy, we
found that the relaxation times at 0 < E-E_F < 0.2 eV are doping dependent and
about 100 fs shorter at optimal doping than for overdoped and parent compounds.
Analysis of the relaxation rates also reveals the presence of a pump fluence
dependent step in the relaxation time at E-E_F = 200meV which we explain by
coupling of the excited electronic system to a boson of this energy. We compare
our results with static ARPES and transport measurements and find disagreement
and agreement concerning the doping-dependence, respectively. We discuss the
effect of the electron-boson coupling on the energy-dependent relaxation and
assign the origin of the boson to a magnetic excitation.
| [
"cond-mat.supr-con"
] | cond-mat.supr-con | Superconductivity | 7,066Superconductivity
|
|
1503.01110 | In this paper, we present the first results from the Renaissance Simulations,
a suite of extremely high-resolution and physics-rich AMR calculations of high
redshift galaxy formation performed on the Blue Waters supercomputer. These
simulations contain hundreds of well-resolved galaxies at $z \sim 25-8$, and
make several novel, testable predictions. Most critically, we show that the
ultraviolet luminosity function of our simulated galaxies is consistent with
observations of high-z galaxy populations at the bright end of the luminosity
function (M$_{1600} \leq -17$), but at lower luminosities is essentially flat
rather than rising steeply, as has been inferred by Schechter function fits to
high-z observations, and has a clearly-defined lower limit in UV luminosity.
This behavior of the luminosity function is due to two factors: (i) the strong
dependence of the star formation rate on halo virial mass in our simulated
galaxy population, with lower-mass halos having systematically lower star
formation rates and thus lower UV luminosities; and (ii) the fact that halos
with virial masses below $\simeq 2 \times 10^8$ M$_\odot$ do not universally
contain stars, with the fraction of halos containing stars dropping to zero at
$\simeq 7 \times 10^6$ M$_\odot$. Finally, we show that the brightest of our
simulated galaxies may be visible to current and future ultra-deep space-based
surveys, particularly if lensed regions are chosen for observation.
| [
"astro-ph.GA"
] | astro-ph.GA | Astrophysics of Galaxies | 464Astrophysics of Galaxies
|
|
hep-ph/9704214 | If a leptoquark is produced at HERA as a narrow resonance, various effects
tend to broaden the measurable mass distribution considerably. These effects
are discussed here, with special emphasis on initial- and final-state QCD
radiation. A proper understanding is important to assess the significance of
data and to devise strategies for better mass reconstruction.
| [
"hep-ph"
] | hep-ph | High Energy Physics - Phenomenology | 3,129High Energy Physics - Phenomenology
|
|
2312.01005 | In this paper, we introduce a novel data augmentation methodology based on
Conditional Progressive Generative Adversarial Networks (CPGAN) to generate
diverse black hole (BH) images, accounting for variations in spin and electron
temperature prescriptions. These generated images are valuable resources for
training deep learning algorithms to accurately estimate black hole parameters
from observational data. Our model can generate BH images for any spin value
within the range of [-1, 1], given an electron temperature distribution. To
validate the effectiveness of our approach, we employ a convolutional neural
network to predict the BH spin using both the GRMHD images and the images
generated by our proposed model. Our results demonstrate a significant
performance improvement when training is conducted with the augmented dataset
while testing is performed using GRMHD simulated data, as indicated by the high
R2 score. Consequently, we propose that GANs can be employed as cost effective
models for black hole image generation and reliably augment training datasets
for other parameterization algorithms.
| [
"astro-ph.GA",
"cs.LG",
"eess.IV"
] | astro-ph.GA | cs.LG | Astrophysics of Galaxies;Machine Learning;Image and Video Processing | 7,267longtail
|
hep-th/0510038 | In this Letter we have proposed a point particle model that generates a
noncommutative three-space, with the coordinate brackets being Lie algebraic in
nature, in particular isomorphic to the angular momentum algebra. The work is
in the spirit of our earlier works in this connection,
{\it {i.e.}} PLB 618 (2005)243 and PLB 623 (2005)251, where the $\kappa
$-Minkowski form of noncomutative spacetime was considered. This non-linear and
operatorial nature of the configuration space coordinate algebra can pose
problems regarding its quantization. This prompts us to embed the model in the
Batalin-Tyutin extended space where the equivalent model comprises of phase
space variables satisfying a canonical algebra. We also compare our present
model with the point particle model, previously proposed by us, in the context
of $\kappa$-Minkowski spacetime.
| [
"hep-th"
] | hep-th | High Energy Physics - Theory | 3,266High Energy Physics - Theory
|
|
2209.08611 | This paper presents a solution to the automatic task planning problem for
multi-agent systems. A formal framework is developed based on the
Nondeterministic Finite Automata with $\epsilon$-transitions, where given the
capabilities, constraints and failure modes of the agents involved, an initial
state of the system and a task specification, an optimal solution is generated
that satisfies the system constraints and the task specification. The resulting
solution is guaranteed to be complete and optimal; moreover a heuristic
solution that offers significant reduction of the computational requirements
while relaxing the completeness and optimality requirements is proposed. The
constructed system model is independent from the initial condition and the task
specification, alleviating the need to repeat the costly pre-processing cycle
for solving other scenarios, while allowing the incorporation of failure modes
on-the-fly. Two case studies are provided: a simple one to showcase the
concepts of the proposed methodology and a more elaborate one to demonstrate
the effectiveness and validity of the methodology.
| [
"cs.RO",
"cs.FL"
] | cs.RO | cs.FL | Robotics;Formal Languages and Automata Theory | 7,267longtail
|
0707.3148 | We use data from observational cosmology to put constraints on
higher-dimensional extensions of general relativity in which the effective
four-dimensional dark-energy density (or cosmological "constant") decays with
time. In particular we study the implications of this decaying dark energy for
the age of the universe, large-scale structure formation, big-bang
nucleosynthesis and the magnitude-redshift relation for Type Ia supernovae. Two
of these tests (age and the magnitude-redshift relation) place modest lower
limits on the free parameter of the theory, a cosmological length scale L akin
to the de Sitter radius. These limits will improve if experimental
uncertainties on supernova magnitudes can be reduced around z=1.
| [
"astro-ph"
] | astro-ph | Astrophysics | 463Astrophysics
|
|
2010.12261 | In this paper we establish the well-posedness of the Muskat problem with
surface tension and equal viscosities in the subcritical Sobolev spaces
$W^s_p(\mathbb{R})$, where ${p\in(1,2]}$ and ${s\in(1+1/p,2)}$. This is
achieved by showing that the mathematical model can be formulated as a
quasilinear parabolic evolution problem in $W^{\overline{s}-2}_p(\mathbb{R})$,
where ${\overline{s}\in(1+1/p,s)}$. Moreover, we prove that the solutions
become instantly smooth and we provide a criterion for the global existence of
solutions.
| [
"math.AP"
] | math.AP | Analysis of PDEs | 205Analysis of PDEs
|
|
1403.2634 | In [Bl1], it is proved that a subgroup of $PL_{+}(I)$ has a finite height if
and only if it is solvable. We prove the "only if" part for any subgroup of
Homeo$_{+}(I)$, and present a construction which indicates a plethora of
examples of solvable groups with infinite height.
| [
"math.GR",
"math.DS"
] | math.GR | math.DS | Group Theory;Dynamical Systems | 2,939Group Theory;Dynamical Systems
|
1012.4269 | Let $X$ be an analytic space of pure dimension. We introduce a formalism to
generate intrinsic weighted Koppelman formulas on $X$ that provide solutions to
the $\dbar$-equation. We obtain new existence results for the $\dbar$-equation,
as well as new proofs of various known results.
| [
"math.CV"
] | math.CV | Complex Variables | 1,135Complex Variables
|
|
1811.07093 | In this manuscript we investigate the long-term behavior of a single-species
fishery, which is harvested by several fleets. The time evolution of this
population is modeled by a discrete time stochastic age-structured model. We
assume that incertitude only affects the recruitment. First, for the
deterministic version of this model, we characterize the equilibrium yields in
terms of the fishing mortality. Then, for the stochastic version, we introduce
the concepts of maximum expected, log expected and harmonic expected
sustainable yield, and we analyze how the incertitude affects the behavior of
these yields and their stationary distribution. All the numerical simulations
are performed with data obtained from Patagonian Tooth-fish fishery, which is
harvested by four different type of fleets: Chilean Industrial fleet, Chilean
Artisanal fleet, Argentinean longline fleet, and Argentinean Artisanal fleet.
| [
"q-bio.PE"
] | q-bio.PE | Populations and Evolution | 5,627Populations and Evolution
|
|
0712.0768 | The strange quark mass is determined from a new QCD Finite Energy Sum Rule
(FESR) optimized to reduce considerably the systematic uncertainties arising
from the hadronic resonance sector. As a result, the main uncertainty in this
determination is due to the value of $\Lambda_{QCD}$. The correlator of
axial-vector divergences is used in perturbative QCD to five-loop order,
including quark and gluon condensate contributions, in the framework of both
Fixed Order (FOPT), and Contour Improved Perturbation Theory (CIPT). The latter
exhibits very good convergence, leading to a remarkably stable result in the
very wide range $s_0 = 1.0 - 4.0 {GeV}^2$, where $s_0$ is the radius of the
integration contour in the complex energy (squared) plane. The value of the
strange quark mass in this framework at a scale of 2 GeV is $m_s(2 {GeV}) = 95
\pm 5 (111 \pm 6) {MeV}$ for $\Lambda_{QCD} = 420
(330) {MeV}$, respectively.
| [
"hep-ph",
"hep-lat"
] | hep-ph | hep-lat | High Energy Physics - Phenomenology;High Energy Physics - Lattice | 3,218High Energy Physics - Phenomenology;High Energy Physics - Lattice
|
0810.4991 | A branching process in random environment $(Z_n, n \in \N)$ is a
generalization of Galton Watson processes where at each generation the
reproduction law is picked randomly. In this paper we give several results
which belong to the class of {\it large deviations}. By contrast to the
Galton-Watson case, here random environments and the branching process can
conspire to achieve atypical events such as $Z_n \le e^{cn}$ when $c$ is
smaller than the typical geometric growth rate $\bar L$ and $ Z_n \ge e^{cn}$
when $c > \bar L$. One way to obtain such an atypical rate of growth is to have
a typical realization of the branching process in an atypical sequence of
environments. This gives us a general lower bound for the rate of decrease of
their probability. When each individual leaves at least one offspring in the
next generation almost surely, we compute the exact rate function of these
events and we show that conditionally on the large deviation event, the
trajectory $t \mapsto \frac1n \log Z_{[nt]}, t\in [0,1]$ converges to a
deterministic function $f_c :[0,1] \mapsto \R_+$ in probability in the sense of
the uniform norm. The most interesting case is when $c < \bar L$ and we
authorize individuals to have only one offspring in the next generation. In
this situation, conditionally on $Z_n \le e^{cn}$, the population size stays
fixed at 1 until a time $ \sim n t_c$. After time $n t_c$ an atypical sequence
of environments let $Z_n$ grow with the appropriate rate ($\neq \bar L$) to
reach $c.$ The corresponding map $f_c(t)$ is piecewise linear and is 0 on
$[0,t_c]$ and $f_c(t) = c(t-t_c)/(1-t_c)$ on $[t_c,1].$
| [
"math.PR"
] | math.PR | Probability | 5,709Probability
|
|
2206.03511 | (Abridged) The lifetime of protoplanetary disks around young stars limits the
timescale when planets form. A disk dissipation timescale < 10 Myr was inferred
from surveys providing the fraction of stars with disks in young stellar
clusters with different ages. However, most previous surveys focused on the
compact region within ~ 2 pc from the clusters' centers, for which the disk
fraction information considering the outer part is practically absent. We aim
to test if disk fraction estimates change when inferred from an extended region
around the clusters' centers. Gaia EDR3 data and a best-suited, Virtual
Observatory (VO)-based tool -Clusterix-, are used to identify member stars for
a representative sample of 19 young clusters considering two concentric fields
of view (FOV) with radii ~ 20 pc and ~ 2 pc. Our analysis reveals that the
inner disk fractions inferred from the compact and the extended regions are
equal within ~ 10%, which does not support a previous hypothesis proposing that
disk fractions should be significantly larger considering extended regions. A
list of member and disk stars in each cluster is provided and stored in a
VO-compliant archive. Averaged values and plots characterizing the whole
clusters are also provided, including HR diagrams based on Gaia colors and
absolute magnitudes. Our results cover the largest fields ever probed when
dealing with disk fractions for all clusters analysed, and imply that their
complete characterization requires the use of wide FOVs. The resulting database
is a benchmark for future detailed studies of young clusters, whose disk
fractions must be accurately determined by using multi-wavelength analysis
potentially combined with data from coming Gaia releases.
| [
"astro-ph.SR"
] | astro-ph.SR | Solar and Stellar Astrophysics | 6,668Solar and Stellar Astrophysics
|
|
2304.05219 | Classic no-regret online prediction algorithms, including variants of the
Upper Confidence Bound ($\texttt{UCB}$) algorithm, $\texttt{Hedge}$, and
$\texttt{EXP3}$, are inherently unfair by design. The unfairness stems from
their very objective of playing the most rewarding arm as many times as
possible while ignoring the less rewarding ones among $N$ arms. In this paper,
we consider a fair prediction problem in the stochastic setting with hard lower
bounds on the rate of accrual of rewards for a set of arms. We study the
problem in both full and bandit feedback settings. Using queueing-theoretic
techniques in conjunction with adversarial learning, we propose a new online
prediction policy called $\texttt{BanditQ}$ that achieves the target reward
rates while achieving a regret and target rate violation penalty of
$O(T^{\frac{3}{4}}).$ In the full-information setting, the regret bound can be
further improved to $O(\sqrt{T})$ when considering the average regret over the
entire horizon of length $T$. The proposed policy is efficient and admits a
black-box reduction from the fair prediction problem to the standard MAB
problem with a carefully defined sequence of rewards. The design and analysis
of the $\texttt{BanditQ}$ policy involve a novel use of the potential function
method in conjunction with scale-free second-order regret bounds and a new
self-bounding inequality for the reward gradients, which are of independent
interest.
| [
"cs.LG",
"cs.PF"
] | cs.LG | cs.PF | Machine Learning;Performance | 4,238Machine Learning;Performance
|
0809.0111 | If in the Randall and Sundrum RS1 model the inverse of the compactification
radius, the AdS curvature scale, and the five and four-dimensional Planck
scales are equal in size, as is natural, then the warp factor at the location
of the low energy brane is of value 1/pi. So that all scales derive from
locations in the space, we identify the extra dimension with the infinite
covering space of the S1/Z2 orbifold. The extra dimension is then essentially a
series of connected line intervals, punctuated by branes. Scales on successive
branes in the extra dimension descend from Planck scale in a geometric sequence
of common ratio 1/pi. Evidence is provided for such a sequence within the
spectrum of particle masses, and of a second geometric sequence, of common
ratio 2/pi, which suggests that the AdS spacetime is six-dimensional and doubly
warped. The scales of the Standard Model lie at coincident levels within the
two sequences. A third sequence, of common ratio 1/e, provides a symmetrical
framework for the Standard Model and points to a warped product spacetime.
| [
"physics.gen-ph"
] | physics.gen-ph | General Physics | 2,645General Physics
|
|
2210.06417 | The issue of bias (i.e., systematic unfairness) in machine learning models
has recently attracted the attention of both researchers and practitioners. For
the graph mining community in particular, an important goal toward algorithmic
fairness is to detect and mitigate bias incorporated into graph embeddings
since they are commonly used in human-centered applications, e.g., social-media
recommendations. However, simple analytical methods for detecting bias
typically involve aggregate statistics which do not reveal the sources of
unfairness. Instead, visual methods can provide a holistic fairness
characterization of graph embeddings and help uncover the causes of observed
bias. In this work, we present BiaScope, an interactive visualization tool that
supports end-to-end visual unfairness diagnosis for graph embeddings. The tool
is the product of a design study in collaboration with domain experts. It
allows the user to (i) visually compare two embeddings with respect to
fairness, (ii) locate nodes or graph communities that are unfairly embedded,
and (iii) understand the source of bias by interactively linking the relevant
embedding subspace with the corresponding graph topology. Experts' feedback
confirms that our tool is effective at detecting and diagnosing unfairness.
Thus, we envision our tool both as a companion for researchers in designing
their algorithms as well as a guide for practitioners who use off-the-shelf
graph embeddings.
| [
"cs.HC",
"cs.CY",
"cs.GR",
"cs.SI"
] | cs.HC | cs.CY | Human-Computer Interaction;Computers and Society;Graphics;Social and Information Networks | 7,267longtail
|
1902.09121 | We discuss the compatibility of the combined annual modulation effect
measured by DAMA/LIBRA-phase1 and DAMA/LIBRA-phase2 with an explanation in
terms of inelastic scattering events induced by the most general
Galilean-invariant effective contact interaction of a Weakly Interacting
Massive Particle (WIMP) dark matter particle of spin 0, 1/2 or 1. We take into
account all the possible interferences among operators by studying the
intersections among the ellipsoidal surfaces of constant signal of DAMA and
other experiments in the space of the coupling constants of the effective
theory. In our analysis we assume a standard Maxwellian velocity distribution
in the Galaxy. We find that, compared to the elastic case, inelastic scattering
partially relieves but does not eliminate the existing tension between the DAMA
effect and the constraints from the null results of other experiments. Such
tension is very large in all the parameter space with the exception of a small
region for WIMP mass $m_{\chi}\simeq$ 10 GeV and mass splitting $\delta\gtrsim$
20 keV, where it is partially, but not completely relieved. In such region the
bounds from fluorine targets are evaded in a kinematic way because the minimal
WIMP incoming speed required to trigger upscatters off fluorine exceeds the
maximal WIMP velocity in the Galaxy, or is very close to it. As a consequence,
we also find that the residual tension between DAMA and other results is more
sensitive on the astrophysical parameters compared to the elastic case. We find
that the configurations with the smallest tension can produce enough yearly
modulation in some of the DAMA bins in compliance with the constraints from
other experiments, but the ensuing shape of the modulation spectrum is too
steep compared to the measured one. For such configurations the recent
COSINE-100 bound is evaded in a natural way due to their large expected
modulation fractions.
| [
"hep-ph"
] | hep-ph | High Energy Physics - Phenomenology | 3,129High Energy Physics - Phenomenology
|
|
0904.2089 | The third moments of conserved charges, the baryon and electric charge
numbers, and energy, as well as their mixed moments, carry more information on
the state around the QCD phase boundary than previously proposed fluctuation
observables and higher order moments. In particular, their signs give plenty of
information on the location of the state created in relativistic heavy ion
collisions in the temperature and baryon chemical potential plane. We
demonstrate this with an effective model.
| [
"nucl-th",
"hep-ph",
"nucl-ex"
] | nucl-th | hep-ph | Nuclear Theory;High Energy Physics - Phenomenology;Nuclear Experiment | 4,919Nuclear Theory;High Energy Physics - Phenomenology;Nuclear Experiment
|
1709.03517 | This paper introduces "Multi-Level Spherical LSH": parameter-free, a
multi-level, data-dependant Locality Sensitive Hashing data structure for
solving the Approximate Near Neighbors Problem (ANN). This data structure uses
a modified version of a multi-probe adaptive querying algorithm, with the
potential of achieving a $O(n^p + t)$ query run time, for all inputs n where $t
<= n$.
| [
"cs.DS"
] | cs.DS | Data Structures and Algorithms | 1,908Data Structures and Algorithms
|
|
0902.3783 | An $k$-noncrossing RNA structure can be identified with an $k$-noncrossing
diagram over $[n]$, which in turn corresponds to a vacillating tableaux having
at most $(k-1)$ rows. In this paper we derive the limit distribution of
irreducible substructures via studying their corresponding vacillating
tableaux. Our main result proves, that the limit distribution of the numbers of
irreducible substructures in $k$-noncrossing, $\sigma$-canonical RNA structures
is determined by the density function of a $\Gamma(-\ln\tau_k,2)$-distribution
for some $\tau_k<1$.
| [
"q-bio.BM",
"math.CO",
"q-bio.QM"
] | q-bio.BM | math.CO | Biomolecules;Combinatorics;Quantitative Methods | 7,267longtail
|
2006.05479 | Principal Component Analysis (PCA) minimizes the reconstruction error given a
class of linear models of fixed component dimensionality. Probabilistic PCA
adds a probabilistic structure by learning the probability distribution of the
PCA latent space weights, thus creating a generative model. Autoencoders (AE)
minimize the reconstruction error in a class of nonlinear models of fixed
latent space dimensionality and outperform PCA at fixed dimensionality. Here,
we introduce the Probabilistic Autoencoder (PAE) that learns the probability
distribution of the AE latent space weights using a normalizing flow (NF). The
PAE is fast and easy to train and achieves small reconstruction errors, high
sample quality, and good performance in downstream tasks. We compare the PAE to
Variational AE (VAE), showing that the PAE trains faster, reaches a lower
reconstruction error, and produces good sample quality without requiring
special tuning parameters or training procedures. We further demonstrate that
the PAE is a powerful model for performing the downstream tasks of
probabilistic image reconstruction in the context of Bayesian inference of
inverse problems for inpainting and denoising applications. Finally, we
identify latent space density from NF as a promising outlier detection metric.
| [
"cs.LG",
"stat.ML"
] | cs.LG | stat.ML | Machine Learning;Machine Learning | 4,163Machine Learning;Machine Learning
|
1403.7050 | This book is an attempt to help students transform all of the concepts of
quantum mechanics into concrete computer representations, which can be
constructed, evaluated, analyzed, and hopefully understood at a deeper level
than what is possible with more abstract representations. It was written for a
Master's and PhD lecture given yearly at the University of Basel, Switzerland.
The goal is to give a language to the student in which to speak about quantum
physics in more detail, and to start the student on a path of fluency in this
language. On our journey we approach questions such as: -- You already know how
to calculate the energy eigenstates of a single particle in a simple
one-dimensional potential. How can such calculations be generalized to
non-trivial potentials, higher dimensions, and interacting particles? -- You
have heard that quantum mechanics describes our everyday world just as well as
classical mechanics does, but have you ever seen an example where such behavior
is calculated in detail and where the transition from classical to quantum
physics is evident? -- How can we describe the internal spin structure of
particles? How does this internal structure couple to the particles' motion? --
What are qubits and quantum circuits, and how can they be assembled to simulate
a future quantum computer?
| [
"quant-ph",
"physics.ed-ph"
] | quant-ph | physics.ed-ph | Quantum Physics;Physics Education | 6,162Quantum Physics;Physics Education
|
1209.5253 | We study the newly discovered Pt phosphides $A$Pt$_3$P ($A$=Sr, Ca, La) [ T.
Takayama et al. Phys. Rev. Lett. 108, 237001 (2012)] using first-principles
calculations and Migdal-Eliashberg theory. Given the remarkable agreement with
the experiment, we exclude the charge-density wave scenario proposed by
previous first-principles calculations, and give conclusive answers concerning
the superconducting state in these materials. The pairing increases from La to
Ca and Sr due to changes in the electron-phonon matrix elements and
low-frequency phonons. Although we find that all three compounds are well
described by conventional s-wave superconductivity and spin-orbit coupling of
Pt plays a marginal role, we show that it could be possible to tune the
structure from centrosymmetric to noncentrosymmetric opening new perspectives
towards the understanding of unconventional superconductivity.
| [
"cond-mat.supr-con"
] | cond-mat.supr-con | Superconductivity | 7,066Superconductivity
|
|
1906.05049 | Let $G/H$ be a contractible homogeneous Sasaki manifold. A compact locally
homogeneous aspherical Sasaki manifold $\Gamma\big\backslash G/H$ is by
definition a quotient of $G/H$ by a discrete uniform subgroup $\Gamma\leq G$.
We show that a compact locally homogeneous aspherical Sasaki manifold is always
quasi-regular, that is, $\Gamma\big\backslash G/H$ is an $S^{1}$-Seifert bundle
over a locally homogeneous aspherical K\"ahler orbifold. We discuss the
structure of the isometry group $\mathrm{Isom}(G/H)$ for a Sasaki metric of
$G/H$ in relation with the pseudo-Hermitian group $\mathrm{Psh} (G/H)$ for the
Sasaki structure of $G/H$. We show that a Sasaki Lie group $G$, when
$\Gamma\big\backslash G$ is a compact locally homogeneous aspherical Sasaki
manifold, is either the universal covering group of $SL(2,R)$ or a modification
of a Heisenberg nilpotent Lie group with its natural Sasaki structure. In
addition, we classify all aspherical Sasaki homogeneous spaces for semisimple
Lie groups.
| [
"math.DG",
"math.CV"
] | math.DG | math.CV | Differential Geometry;Complex Variables | 2,036Differential Geometry;Complex Variables
|
2008.02932 | Programming language concepts are used to give some new perspectives on a
long-standing open problem: is logspace = ptime ?
| [
"cs.CC",
"cs.PL"
] | cs.CC | cs.PL | Computational Complexity;Programming Languages | 7,267longtail
|