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2111.01588 | We present explicit equations for the space of conics in the Fermat quintic
threefold $X$, working within the space of plane sections of $X$ with two
singular marked points. This space of two-pointed singular plane sections has a
birational morphism to the space of bitangent lines to the Fermat quintic
threefold, which in its turn is birational to a 625-to-1 cover of $\PP^4.$ We
illustrate the use of the resulting equations in identifying special cases of
one-dimensional families of conics in $X.$
| [
"math.AG"
] | math.AG | Algebraic Geometry | 47Algebraic Geometry
|
|
hep-th/0404156 | Causal Dynamical Triangulations in four dimensions provide a
background-independent definition of the sum over geometries in nonperturbative
quantum gravity, with a positive cosmological constant. We present evidence
that a macroscopic four-dimensional world emerges from this theory dynamically.
| [
"hep-th",
"gr-qc"
] | hep-th | gr-qc | High Energy Physics - Theory;General Relativity and Quantum Cosmology | 3,321High Energy Physics - Theory;General Relativity and Quantum Cosmology
|
1702.07362 | The conformal crossing equation puts very stringent constraints on the
conformal data. We formulate it in way that makes the conformal symmetry more
transparent. This allows for generalization of the crossing equation to
arbitrary Lie group G. Using the crossing equation for SU(2) as a toy model, we
find infinitely many solutions to the G-crossing equation. In particular, when
G is specialized to the conformal group SO(d+1,1), we get infinitely many
solutions to the conformal crossing equation.
| [
"hep-th"
] | hep-th | High Energy Physics - Theory | 3,266High Energy Physics - Theory
|
|
hep-ph/0311361 | We analyse supersymmetric contributions to B_s mixing and their impact on
mixing-induced CP asymmetries, using the mass insertion approximation. We
discuss in particular the correlation of SUSY effects in the CP asymmetries of
B_s -> J/psi phi and B_d -> phi K_S and find that the mass insertions dominant
in B_s mixing and B_d -> phi K_S are (delta_{23}^d)_{LL, RR} and
(delta_{23}^d)_{LR, RL}, respectively. We show that models with dominant
(delta_{23}^d)_{LR, RL} can accomodate a negative value of S_{phi K_S}, in
agreement with the BELLE measurement of that observable, but yield a B_s mixing
phase too small to be observed. On the other hand, models with dominant
(delta_{23}^d)_{LL, RR} predict sizeable SUSY contributions to both Delta M_s
and the mixing phase, but do not allow the asymmetry in B_d -> phi K_S to
become negative, except for small values of the average down squark mass,
which, in turn, entail a value of Delta M_s too large to be observed at the
Tevatron and the LHC. We conclude that the observation of B_s mixing at hadron
machines, together with the confirmation of a negative value of S_{phi K_S},
disfavours models with a single dominant mass insertion.
| [
"hep-ph"
] | hep-ph | High Energy Physics - Phenomenology | 3,129High Energy Physics - Phenomenology
|
|
1110.6719 | We present an investigation of heat transport in gapless graphene-based
Ferromagnetic /singlet Superconductor/Ferromagnetic (FG$\mid$SG$\mid$FG)
junctions. We find that unlike uniform increase of thermal conductance vs
temperature, the thermal conductance exhibits intensive oscillatory behavior vs
width of the sandwiched s-wave superconducting region between the two
ferromagnetic layers. This oscillatory form is occurred by interference of the
massless Dirac fermions in graphene. Also we find that the thermal conductance
vs exchange field $h$ displays a minimal value at $h/E_F\simeq 1$ within the
low temperature regime where this finding demonstrates that propagating modes
of the Dirac fermions in this value reach at their minimum numbers and verifies
the previous results for electronic conductance. We find that for thin widths
of superconducting region, the thermal conductance vs temperature shows linear
increment i.e. $\Gamma\varpropto T$. At last we propose an experimental set-up
to detect our predicted effects.
| [
"cond-mat.supr-con"
] | cond-mat.supr-con | Superconductivity | 7,066Superconductivity
|
|
2005.09348 | Continuous invariants are an important component in deductive verification of
hybrid and continuous systems. Just like discrete invariants are used to reason
about correctness in discrete systems without having to unroll their loops,
continuous invariants are used to reason about differential equations without
having to solve them. Automatic generation of continuous invariants remains one
of the biggest practical challenges to the automation of formal proofs of
safety for hybrid systems. There are at present many disparate methods
available for generating continuous invariants; however, this wealth of diverse
techniques presents a number of challenges, with different methods having
different strengths and weaknesses. To address some of these challenges, we
develop Pegasus: an automatic continuous invariant generator which allows for
combinations of various methods, and integrate it with the KeYmaera X theorem
prover for hybrid systems. We describe some of the architectural aspects of
this integration, comment on its methods and challenges, and present an
experimental evaluation on a suite of benchmarks.
| [
"cs.SC",
"cs.LO"
] | cs.SC | cs.LO | Symbolic Computation;Logic in Computer Science | 7,116Symbolic Computation;Logic in Computer Science
|
1605.03513 | We measure the forward-backward asymmetries $A_{\rm FB}$ of charged $\Xi$ and
$\Omega$ baryons produced in $p \bar{p}$ collisions recorded by the D0 detector
at the Fermilab Tevatron collider at $\sqrt{s} = 1.96$ TeV as a function of the
baryon rapidity $y$. We find that the asymmetries $A_{\rm FB}$ for charged
$\Xi$ and $\Omega$ baryons are consistent with zero within statistical
uncertainties.
| [
"hep-ex"
] | hep-ex | High Energy Physics - Experiment | 3,059High Energy Physics - Experiment
|
|
1509.06433 | In quantum field theories with topological sectors, a non-perturbative
quantity of interest is the topological susceptibility chi_t. In principle it
seems straightforward to measure chi_t by means of Monte Carlo simulations.
However, for local update algorithms and fine lattice spacings, this tends to
be difficult, since the Monte Carlo history rarely changes the topological
sector. Here we test a method to measure chi_t even if data from only one
sector are available. It is based on the topological charges in sub-volumes,
which we denote as slabs. Assuming a Gaussian distribution of these charges,
this method enables the evaluation of chi_t, as we demonstrate with numerical
results for non-linear sigma-models.
| [
"hep-lat",
"hep-ph"
] | hep-lat | hep-ph | High Energy Physics - Lattice;High Energy Physics - Phenomenology | 3,105High Energy Physics - Lattice;High Energy Physics - Phenomenology
|
2006.09207 | We prove large deviation results for the position of the rightmost particle,
denoted by $M_n$, in a one-dimensional branching random walk in a case when
Cram\'er's condition is not satisfied. More precisely we consider step size
distributions with stretched exponential upper and lower tails, i.e.~both tails
decay as $e^{-|t|^r}$ for some $r\in( 0,1)$. It is known that in this case,
$M_n$ grows as $n^{1/r}$ and in particular faster than linearly in $n$. Our
main result is a large deviation principle for the laws of $n^{-1/r}M_n$ . In
the proof we use a comparison with the maximum of (a random number of)
independent random walks, denoted by $\tilde M_n$, and we show a large
deviation principle for the laws of $n^{-1/r}\tilde M_n$ as well.
| [
"math.PR"
] | math.PR | Probability | 5,709Probability
|
|
2208.13121 | Existing domain adaptation methods assume that domain discrepancies are
caused by a few discrete attributes and variations, e.g., art, real, painting,
quickdraw, etc. We argue that this is not realistic as it is implausible to
define the real-world datasets using a few discrete attributes. Therefore, we
propose to investigate a new problem namely the Continuous Domain Adaptation
(CDA) through the lens where infinite domains are formed by continuously
varying attributes. Leveraging knowledge of two labeled source domains and
several observed unlabeled target domains data, the objective of CDA is to
learn a generalized model for whole data distribution with the continuous
attribute. Besides the contributions of formulating a new problem, we also
propose a novel approach as a strong CDA baseline. To be specific, firstly we
propose a novel alternating training strategy to reduce discrepancies among
multiple domains meanwhile generalize to unseen target domains. Secondly, we
propose a continuity constraint when estimating the cross-domain divergence
measurement. Finally, to decouple the discrepancy from the mini-batch size, we
design a domain-specific queue to maintain the global view of the source domain
that further boosts the adaptation performances. Our method is proven to
achieve the state-of-the-art in CDA problem using extensive experiments. The
code is available at https://github.com/SPIresearch/CDA.
| [
"cs.CV"
] | cs.CV | Computer Vision and Pattern Recognition | 1,498Computer Vision and Pattern Recognition
|
|
math/0305110 | We introduce a general notion of twistorial map and classify twistorial
harmonic morphisms with one-dimensional fibres from self-dual four-manifolds.
Such maps can be characterised as those which pull back Abelian monopoles to
self-dual connections. In fact, the constructions involve solving a generalised
monopole equation, and also the Beltrami fields equation of hydrodynamics, and
lead to constructions of self-dual metrics.
| [
"math.DG"
] | math.DG | Differential Geometry | 2,010Differential Geometry
|
|
2111.01124 | Contrastive learning (CL) can learn generalizable feature representations and
achieve the state-of-the-art performance of downstream tasks by finetuning a
linear classifier on top of it. However, as adversarial robustness becomes
vital in image classification, it remains unclear whether or not CL is able to
preserve robustness to downstream tasks. The main challenge is that in the
self-supervised pretraining + supervised finetuning paradigm, adversarial
robustness is easily forgotten due to a learning task mismatch from pretraining
to finetuning. We call such a challenge 'cross-task robustness
transferability'. To address the above problem, in this paper we revisit and
advance CL principles through the lens of robustness enhancement. We show that
(1) the design of contrastive views matters: High-frequency components of
images are beneficial to improving model robustness; (2) Augmenting CL with
pseudo-supervision stimulus (e.g., resorting to feature clustering) helps
preserve robustness without forgetting. Equipped with our new designs, we
propose AdvCL, a novel adversarial contrastive pretraining framework. We show
that AdvCL is able to enhance cross-task robustness transferability without
loss of model accuracy and finetuning efficiency. With a thorough experimental
study, we demonstrate that AdvCL outperforms the state-of-the-art
self-supervised robust learning methods across multiple datasets (CIFAR-10,
CIFAR-100, and STL-10) and finetuning schemes (linear evaluation and full model
finetuning).
| [
"cs.CV",
"cs.AI",
"cs.LG"
] | cs.CV | cs.AI | Computer Vision and Pattern Recognition;Artificial Intelligence;Machine Learning | 1,521Computer Vision and Pattern Recognition;Artificial Intelligence;Machine Learning
|
1804.01436 | We use high-resolution angle-resolved photoemission spectroscopy to map the
three-dimensional momentum dependence of the superconducting gap in FeSe. We
find that on both the hole and electron Fermi surfaces, the magnitude of the
gap follows the distribution of $d_{yz}$ orbital weight. Furthermore, we
theoretically determine the momentum dependence of the superconducting gap by
solving the linearized gap equation using a tight binding model which
quantitatively describes both the experimental band dispersions and orbital
characters. By considering a Fermi surface only including one electron pocket,
as observed spectroscopically, we obtain excellent agreement with the
experimental gap structure. Our finding of a scaling between the
superconducting gap and the $d_{yz}$ orbital weight supports the interpretation
of superconductivity mediated by spin-fluctuations in FeSe.
| [
"cond-mat.supr-con",
"cond-mat.str-el"
] | cond-mat.supr-con | cond-mat.str-el | Superconductivity;Strongly Correlated Electrons | 7,102Superconductivity;Strongly Correlated Electrons
|
1406.0846 | Finding the precise correspondence between lattice operators and the
continuum fields that describe their long-distance properties is a largely open
problem for strongly interacting critical points. Here we solve this problem
essentially completely in the case of the three-state Potts model, which
exhibits a phase transition described by a strongly interacting 'parafermion'
conformal field theory. Using symmetry arguments, insights from integrability,
and extensive simulations, we construct lattice analogues of nearly all the
relevant and marginal physical fields governing this transition. This
construction includes chiral fields such as the parafermion. Along the way we
also clarify the structure of operator product expansions between order and
disorder fields, which we confirm numerically. Our results both suggest a
systematic methodology for attacking non-free field theories on the lattice and
find broader applications in the pursuit of exotic topologically ordered phases
of matter.
| [
"cond-mat.stat-mech",
"cond-mat.str-el",
"hep-th"
] | cond-mat.stat-mech | cond-mat.str-el | Statistical Mechanics;Strongly Correlated Electrons;High Energy Physics - Theory | 6,972Statistical Mechanics;Strongly Correlated Electrons;High Energy Physics - Theory
|
1512.03925 | The classical ground state magnetic response of fullerene molecules that
resemble capped carbon nanotubes is calculated within the framework of the
antiferromagnetic Heisenberg model. It is found that the magnetic response
depends subtly on spatial symmetry and chirality. Clusters based on armchair
carbon nanotubes which are capped with non-neighboring pentagons and have D5d
spatial symmetry have a number of magnetization discontinuities which increases
with their size. This occurs even though the model completely lacks magnetic
anisotropy, and even though the only source of frustration are the two groups
of six pentagons located at the ends of the molecules, which become more
strongly outnumbered as the clusters are filled in the middle with more
unfrustrated hexagons with increasing size. For the cluster with 180 vertices
there are already seven magnetization and one susceptibility discontinuities.
Contrary to that, similar molecules which have D5h spatial symmetry reach a
limit of one magnetization and two susceptibility ground state discontinuities,
while fullerene molecules based on zigzag carbon nanotubes and capped by
neighboring pentagons also reach a fixed number of discontinuities with
increasing size.
| [
"cond-mat.str-el"
] | cond-mat.str-el | Strongly Correlated Electrons | 6,979Strongly Correlated Electrons
|
|
2108.01956 | A bounded linear operator $T$ acting on a Hilbert space $\mathcal{H}$ is said
to be recurrent if for every non-empty open subset $U\subset \mathcal{H}$ there
is an integer $n$ such that $T^n (U)\cap U\neq\emptyset$. In this paper, we
completely characterize the recurrence of scalar multiples of composition
operators, induced by linear fractional self maps of the unit disk, acting on
weighted Dirichlet spaces $S_\nu$; in particular on the Bergman space, the
Hardy space, and the Dirichlet space. Consequently, we complete a previous work
of Costakis et al. \cite{costakis} on recurrence of linear fractional
composition operators on Hardy space. In this manner, we determine the triples
$(\lambda,\nu,\phi)\in \mathbb{C}\times \mathbb{R}\times LFM(\mathbb{D})$ for
which the scalar multiple of composition operator $\lambda C_\phi$ acting on
$S_\nu$ fails to be recurrent.
| [
"math.FA"
] | math.FA | Functional Analysis | 2,549Functional Analysis
|
|
0906.3945 | We study a minimal model of traffic flows in complex networks, simple enough
to get analytical results, but with a very rich phenomenology, presenting
continuous, discontinuous as well as hybrid phase transitions between a
free-flow phase and a congested phase, critical points and different scaling
behaviors in the system size. It consists of random walkers on a queueing
network with one-range repulsion, where particles can be destroyed only if they
can move. We focus on the dependence on the topology as well as on the level of
traffic control. We are able to obtain transition curves and phase diagrams at
analytical level for the ensemble of uncorrelated networks and numerically for
single instances. We find that traffic control improves global performance,
enlarging the free-flow region in parameter space only in heterogeneous
networks. Traffic control introduces non-linear effects and, beyond a critical
strength, may trigger the appearance of a congested phase in a discontinuous
manner. The model also reproduces the cross-over in the scaling of traffic
fluctuations empirically observed in the Internet, and moreover, a conserved
version can reproduce qualitatively some stylized facts of traffic in
transportation networks.
| [
"cond-mat.stat-mech",
"physics.soc-ph"
] | cond-mat.stat-mech | physics.soc-ph | Statistical Mechanics;Physics and Society | 6,938Statistical Mechanics;Physics and Society
|
2308.04733 | Text design is one of the most critical procedures in poster design, as it
relies heavily on the creativity and expertise of humans to design text images
considering the visual harmony and text-semantic. This study introduces
TextPainter, a novel multimodal approach that leverages contextual visual
information and corresponding text semantics to generate text images.
Specifically, TextPainter takes the global-local background image as a hint of
style and guides the text image generation with visual harmony. Furthermore, we
leverage the language model and introduce a text comprehension module to
achieve both sentence-level and word-level style variations. Besides, we
construct the PosterT80K dataset, consisting of about 80K posters annotated
with sentence-level bounding boxes and text contents. We hope this dataset will
pave the way for further research on multimodal text image generation.
Extensive quantitative and qualitative experiments demonstrate that TextPainter
can generate visually-and-semantically-harmonious text images for posters.
| [
"cs.CV"
] | cs.CV | Computer Vision and Pattern Recognition | 1,498Computer Vision and Pattern Recognition
|
|
2106.00062 | In this paper, we identify and study an important problem of gradient item
retrieval. We define the problem as retrieving a sequence of items with a
gradual change on a certain attribute, given a reference item and a
modification text. For example, after a customer saw a white dress, she/he
wants to buy a similar one but more floral on it. The extent of "more floral"
is subjective, thus prompting one floral dress is hard to satisfy the
customer's needs. A better way is to present a sequence of products with
increasingly floral attributes based on the white dress, and allow the customer
to select the most satisfactory one from the sequence. Existing item retrieval
methods mainly focus on whether the target items appear at the top of the
retrieved sequence, but ignore the demand for retrieving a sequence of products
with gradual change on a certain attribute. To deal with this problem, we
propose a weakly-supervised method that can learn a disentangled item
representation from user-item interaction data and ground the semantic meaning
of attributes to dimensions of the item representation. Our method takes a
reference item and a modification as a query. During inference, we start from
the reference item and "walk" along the direction of the modification in the
item representation space to retrieve a sequence of items in a gradient manner.
We demonstrate our proposed method can achieve disentanglement through weak
supervision. Besides, we empirically show that an item sequence retrieved by
our method is gradually changed on an indicated attribute and, in the item
retrieval task, our method outperforms existing approaches on three different
datasets.
| [
"cs.IR"
] | cs.IR | Information Retrieval | 3,577Information Retrieval
|
|
2307.09424 | We theoretically propose a scheme to generate distant bipartite entanglement
between various subsystems in coupled magnomechanical systems where both the
microwave cavities are coupled through single photon hopping parameter. Each
cavity also contains a magnon mode and phonon mode and this gives five
excitation modes in our model Hamiltonian which are cavity-1 photons, cavity-2
photons, magnon, and phonon modes in both YIG spheres. We found that
significant bipartite entanglement exists between indirectly coupled subsystems
in coupled microwave cavities for an appropriate set of parameters regime.
Moreover, we also obtain suitable cavity and magnon detuning parameters for a
significant distant bipartite entanglement in different bipartitions. In
addition, it can be seen that a single photon hopping parameter significantly
affects both the degree as well as the transfer of quantum entanglement between
various bipartitions. Hence, our present study related to coupled microwave
cavity magnomechanical configuration will open new perspectives in coherent
control of various quantum correlations including quantum state transfer among
macroscopic quantum systems
| [
"quant-ph"
] | quant-ph | Quantum Physics | 5,985Quantum Physics
|
|
math/0509596 | In the paper I check approaches to identity in mathematics by Plato, Frege,
and Geach against Category theory.
| [
"math.CT"
] | math.CT | Category Theory | 757Category Theory
|
|
1409.4922 | Reductive hydrogenation was applied to two types of single-walled carbon
nanotubes with different diameter range. Alkali metal intercalation, followed
by reaction with methanol, led to hydrogenated products. Both yield and
selectivity of this reaction showed strong dependence on diameter, contrary to
expectation based on simple curvature effects. The observed yield, as detected
by thermogravimetry-mass spectroscopy and 1H-NMR, is drastically reduced in
small-diameter tubes where the alkali dopant does not reach the inside of the
bundles. Wide range optical transmission measurements were employed to
determine the selectivity and indicate that besides higher yield, lower
diameter selectivity occurs above a critical diameter.
| [
"cond-mat.mtrl-sci"
] | cond-mat.mtrl-sci | Materials Science | 4,287Materials Science
|
|
cond-mat/9509131 | We consider the problem of an ideal polymer confined in a droplet. When the
droplet radius is smaller than the (unconfined) polymer radius of gyration, the
polymer entropy will depend on the droplet shape. We compute the resulting
surface free energy. Using parameters appropriate for polymers confined in
microemulsions, we find that the polymer and bending surface energies are
comparable for the lowest modes. Finally, we argue that chain self-avoidance
will decrease the strength of the polymer contribution to the surface energy.
| [
"cond-mat"
] | cond-mat | Condensed Matter | 1,697Condensed Matter
|
|
2010.06336 | In this paper, we study the following problem: given a knowledge graph (KG)
and a set of input vertices (representing concepts or entities) and edge
labels, we aim to find the smallest connected subgraphs containing all of the
inputs. This problem plays a key role in KG-based search engines and natural
language question answering systems, and it is a natural extension of the
Steiner tree problem, which is known to be NP-hard. We present RECON, a system
for finding approximate answers. RECON aims at achieving high accuracy with
instantaneous response (i.e., sub-second/millisecond delay) over KGs with
hundreds of millions edges without resorting to expensive computational
resources. Furthermore, when no answer exists due to disconnection between
concepts and entities, RECON refines the input to a semantically similar one
based on the ontology, and attempt to find answers with respect to the refined
input. We conduct a comprehensive experimental evaluation of RECON. In
particular we compare it with five existing approaches for finding approximate
Steiner trees. Our experiments on four large real and synthetic KGs show that
RECON significantly outperforms its competitors and incurs a much smaller
memory footprint.
| [
"cs.DB"
] | cs.DB | Databases | 1,977Databases
|
|
2212.08343 | A fundamental challenge to providing edge-AI services is the need for a
machine learning (ML) model that achieves personalization (i.e., to individual
clients) and generalization (i.e., to unseen data) properties concurrently.
Existing techniques in federated learning (FL) have encountered a steep
tradeoff between these objectives and impose large computational requirements
on edge devices during training and inference. In this paper, we propose
SplitGP, a new split learning solution that can simultaneously capture
generalization and personalization capabilities for efficient inference across
resource-constrained clients (e.g., mobile/IoT devices). Our key idea is to
split the full ML model into client-side and server-side components, and impose
different roles to them: the client-side model is trained to have strong
personalization capability optimized to each client's main task, while the
server-side model is trained to have strong generalization capability for
handling all clients' out-of-distribution tasks. We analytically characterize
the convergence behavior of SplitGP, revealing that all client models approach
stationary points asymptotically. Further, we analyze the inference time in
SplitGP and provide bounds for determining model split ratios. Experimental
results show that SplitGP outperforms existing baselines by wide margins in
inference time and test accuracy for varying amounts of out-of-distribution
samples.
| [
"cs.LG"
] | cs.LG | Machine Learning | 3,882Machine Learning
|
|
1905.00470 | In this paper, we propose a semi-automatic system for title construction from
scientific abstracts. The system extracts and recommends impactful words from
the text, which the author can creatively use to construct an appropriate title
for the manuscript. The work is based on the hypothesis that keywords are good
candidates for title construction. We extract important words from the document
by inducing a supervised keyword extraction model. The model is trained on
novel features extracted from graph-of-text representation of the document. We
empirically show that these graph-based features are capable of discriminating
keywords from non-keywords. We further establish empirically that the proposed
approach can be applied to any text irrespective of the training domain and
corpus. We evaluate the proposed system by computing the overlap between
extracted keywords and the list of title-words for documents, and we observe a
macro-averaged precision of 82%.
| [
"cs.IR",
"cs.CL"
] | cs.IR | cs.CL | Information Retrieval;Computation and Language | 3,590Information Retrieval;Computation and Language
|
2008.02236 | In this paper, we first present a method to autonomously detect helipads in
real time. Our method does not rely on any machine-learning methods and as such
is applicable in real-time on the computational capabilities of an average
quad-rotor. After initial detection, we use image tracking methods to reduce
the computational resource requirement further. Once the tracking starts our
modified IBVS(Image-Based Visual Servoing) method starts publishing velocity to
guide the quad-rotor onto the helipad. The modified IBVS scheme is designed for
the four degrees-of-freedom of a quad-rotor and can land the quad-rotor in a
specific orientation.
| [
"cs.RO"
] | cs.RO | Robotics | 6,325Robotics
|
|
1402.2828 | This paper presents an algorithm for sampling random variables that allows to
separation of the sampling process into subproblems by dividing the sample
space into overlapping parts. The subproblems can be solved independently of
each other and are thus well suited for parallelization. Furthermore, on each
of these subproblems it is possible to use distinct and independent sampling
methods. In other words, specific samplers can be designed for specific parts
of the sample space. The algorithms are demonstrated on a particle marginal
Metropolis-Hastings sampler applied to calibration of a volatility model and
two toy examples. Significant speedup and decrease of total variation is
observed in experiments.
| [
"stat.CO"
] | stat.CO | Computation | 1,167Computation
|
|
2003.02244 | Implicit discourse relations are not only more challenging to classify, but
also to annotate, than their explicit counterparts. We tackle situations where
training data for implicit relations are lacking, and exploit domain adaptation
from explicit relations (Ji et al., 2015). We present an unsupervised
adversarial domain adaptive network equipped with a reconstruction component.
Our system outperforms prior works and other adversarial benchmarks for
unsupervised domain adaptation. Additionally, we extend our system to take
advantage of labeled data if some are available.
| [
"cs.CL"
] | cs.CL | Computation and Language | 1,168Computation and Language
|
|
1903.06855 | Analyzing plant roots is crucial to understand plant performance in different
soil environments. While magnetic resonance imaging (MRI) can be used to obtain
3D images of plant roots, extracting the root structural model is challenging
due to highly noisy soil environments and low-resolution of MRI images. To
improve both contrast and resolution, we adapt the state-of-the-art method
RefineNet for 3D segmentation of the plant root MRI images in super-resolution.
The networks are trained from few manual segmentations that are augmented by
geometric transformations, realistic noise, and other variabilities. The
resulting segmentations contain most root structures, including branches not
extracted by the human annotator.
| [
"cs.CV",
"cs.LG"
] | cs.CV | cs.LG | Computer Vision and Pattern Recognition;Machine Learning | 1,593Computer Vision and Pattern Recognition;Machine Learning
|
0711.3581 | In this paper we develop a model of an order-driven market where traders set
bids and asks and post market or limit orders according to exogenously fixed
rules. Agents are assumed to have three components to the expectation of future
asset returns, namely-fundamentalist, chartist and noise trader. Furthermore
agents differ in the characteristics describing these components, such as time
horizon, risk aversion and the weights given to the various components. The
model developed here extends a great deal of earlier literature in that the
order submissions of agents are determined by utility maximisation, rather than
the mechanical unit order size that is commonly assumed. In this way the order
flow is better related to the ongoing evolution of the market. For the given
market structure we analyze the impact of the three components of the trading
strategies on the statistical properties of prices and order flows and observe
that it is the chartist strategy that is mainly responsible of the fat tails
and clustering in the artificial price data generated by the model. The paper
provides further evidence that large price changes are likely to be generated
by the presence of large gaps in the book.
| [
"q-fin.TR",
"physics.soc-ph"
] | q-fin.TR | physics.soc-ph | Trading and Market Microstructure;Physics and Society | 7,262Trading and Market Microstructure;Physics and Society
|
hep-ph/0006194 | We discuss the procedure to resum large logarithms to all orders for DIS
event shape variable distributions.
Results are described for two variants of the thrust variable, both defined
wrt the boson axis in the current hemisphere of the Breit frame, but with
different normalisations.
| [
"hep-ph"
] | hep-ph | High Energy Physics - Phenomenology | 3,129High Energy Physics - Phenomenology
|
|
2001.02049 | We present a set-up for time-resolved X-ray diffraction based on a short
pulse, laser-driven plasma X-ray source. The employed modular design provides
high flexibility to adapt the set-up to the specific requirements (e.g. X-ray
optics, sample environment) of particular applications. The configuration
discussed here has been optimized towards high angular/momentum resolution and
uses K$_{\alpha}$-radiation (4.51 keV) from a Ti wire-target in combination
with a toroidally bent crystal for collection, monochromatization and focusing
of the emitted radiation. $2\times 10^5$ Ti-K$_{\alpha1}$ photons per pulse
with $10^{-4}$ relative bandwidth are delivered to the sample at 10 Hz
repetition rate. This allows for high dynamic range ($10^4$) measurements of
transient changes of the rocking curves of materials as for example induced by
laser-triggered strain waves.
| [
"physics.ins-det",
"cond-mat.other",
"physics.optics"
] | physics.ins-det | cond-mat.other | Instrumentation and Detectors;Other Condensed Matter;Optics | 7,267longtail
|
quant-ph/0605046 | Two multi-user approaches to fiber-based quantum key distribution systems
operating at gigahertz clock frequencies are presented, both compatible with
standard telecommunications fiber.
| [
"quant-ph"
] | quant-ph | Quantum Physics | 5,985Quantum Physics
|
|
1210.3216 | The finite time disentanglement or entanglement sudden death, when only one
part of the composite system is subjected to a single noise, is examined. While
it is shown that entanglement sudden death can occur when a part of the
entangled mixed state is subjected to either amplitude noise or phase noise,
local action of either of them does not cause entanglement sudden death in pure
entangled states. In contrast, depolarizing noise is shown to have an abilitiy
to cause sudden death of entanglement even in pure entangled states, when only
one part of the state is exposed to it. The result is illustrated through the
action of different noisy environments individually on a single qubit of the
so-called X class of states and an arbitrary two-qubit pure state.
| [
"quant-ph"
] | quant-ph | Quantum Physics | 5,985Quantum Physics
|
|
astro-ph/9802157 | Recent results on Gamma-Ray Bursts obtained with the X-ray Astronomy
satellite BeppoSAX are reviewed. Main emphasis is given to the GRBs
simultaneously detected with the Gamma-Ray Burst Monitor (40-700 keV) and the
Wide Field Cameras (1.5-26 keV). These bursts were rapidly localized with high
precision, which permitted a prompt pointing of their error boxes with the
Narrow Field Instruments aboard the same satellite. In three cases of bursts,
these prompt observations led to the discovery of an X-ray afterglow. For two
events also an optical transient was discovered. We review these results and
their implications.
| [
"astro-ph"
] | astro-ph | Astrophysics | 463Astrophysics
|
|
1306.3350 | Let \Sigma_g be a closed orientable surface let Diff_0(\Sigma_g; area) be the
identity component of the group of area-preserving diffeomorphisms of \Sigma_g.
In this work we present an extension of Gambaudo-Ghys construction to the case
of a closed hyperbolic surface \Sigma_g, i.e. we show that every non-trivial
homogeneous quasi-morphism on the braid group on n strings of \Sigma_g defines
a non-trivial homogeneous quasi-morphism on the group Diff_0(\Sigma_g; area).
As a consequence we give another proof of the fact that the space of
homogeneous quasi-morphisms on Diff_0(\Sigma_g; area) is infinite dimensional.
Let Ham(\Sigma_g) be the group of Hamiltonian diffeomorphisms of \Sigma_g. As
an application of the above construction we construct two injective
homomorphisms from Z^m to Ham(\Sigma_g), which are bi-Lipschitz with respect to
the word metric on Z^m and the autonomous and fragmentation metrics on
Ham(\Sigma_g). In addition, we construct a new infinite family of Calabi
quasi-morphisms on Ham(\Sigma_g).
| [
"math.GT",
"math.GR",
"math.SG"
] | math.GT | math.GR | Geometric Topology;Group Theory;Symplectic Geometry | 7,267longtail
|
1907.10929 | Analysis of microscope images is a tedious work which requires patience and
time, usually done manually by the microscopist after data collection. Here we
introduce an approach of automatic image analysis, which is based on locally
applied Fourier Transform and Machine Learning methods. In this approach, a
whole image is scanned by a local moving window with defined size and the 2D
Fourier Transform is calculated for each window. Then, all the Local Fourier
Transforms are fed into Machine Learning processing. Firstly, a number of
components in the data is estimated from Principal Component Analysis (PCA)
Scree Plot performed on the data. Secondly, the data are decomposed blindly by
Non-Negative Matrix Factorization (NMF) into interpretable spatial maps
(loadings) and corresponding Fourier Transforms (factors). The microscopic
image is analyzed and the features on the image are automatically discovered,
based on the local changes in Fourier Transform. The user selects only a size
and movement of the scanning local window which defines the final analysis
resolution. This automatic approach was successfully applied to analysis of
various microscopic images with and without local periodicity i.e. atomically
resolved High Angle Annular Dark Field (HAADF) Scanning Transmission Electron
Microscopy (STEM) image of Au nanoisland of fcc and Au hcp phases, Scanning
Tunneling Microscopy (STM) image of Au-induced reconstruction on Ge(001)
surface, Scanning Electron Microscopy (SEM) image of metallic nanoclusters
grown on GaSb surface, and Fluorescence microscopy image of HeLa cell line of
cervical cancer. The proposed approach could be used to automatically analyze
the local structure of microscopic images within a time of about a minute for a
single image on a modern desktop/notebook computer and it is freely available
as a Python analysis notebook and Python program for batch processing.
| [
"eess.IV",
"cond-mat.mes-hall",
"physics.app-ph"
] | eess.IV | cond-mat.mes-hall | Image and Video Processing;Mesoscale and Nanoscale Physics;Applied Physics | 7,267longtail
|
0704.2512 | We present a novel notion of stable objects in the derived category of
coherent sheaves on a smooth projective variety. As one application we
compactify a moduli space of stable bundles using genuine complexes.
| [
"math.AG"
] | math.AG | Algebraic Geometry | 47Algebraic Geometry
|
|
1003.3590 | Type IIA string theory compactified on SU(3)-structure manifolds with
orientifolds allows for classical de Sitter solutions in four dimensions. In
this paper we investigate these solutions from a ten-dimensional point of view.
In particular, we demonstrate that there exists an attractive class of de
Sitter solutions, whose geometry, fluxes and source terms can be entirely
written in terms of the universal forms that are defined on all SU(3)-structure
manifolds. These are the forms J and Omega, defining the SU(3)-structure
itself, and the torsion classes. The existence of such universal de Sitter
solutions is governed by easy-to-verify conditions on the SU(3)-structure,
rendering the problem of finding dS solutions purely geometrical. We point out
that the known (unstable) solution coming from the compactification on SU(2)x
SU(2) is of this kind.
| [
"hep-th"
] | hep-th | High Energy Physics - Theory | 3,266High Energy Physics - Theory
|
|
2105.06363 | This paper presents a proper generalized decomposition (PGD) based
reduced-order model of hierarchical deep-learning neural networks (HiDeNN). The
proposed HiDeNN-PGD method keeps both advantages of HiDeNN and PGD methods. The
automatic mesh adaptivity makes the HiDeNN-PGD more accurate than the finite
element method (FEM) and conventional PGD, using a fraction of the FEM degrees
of freedom. The accuracy and convergence of the method have been studied
theoretically and numerically, with a comparison to different methods,
including FEM, PGD, HiDeNN and Deep Neural Networks. In addition, we
theoretically showed that the PGD converges to FEM at increasing modes, and the
PGD error is a direct sum of the FEM error and the mode reduction error. The
proposed HiDeNN-PGD performs high accuracy with orders of magnitude fewer
degrees of freedom, which shows a high potential to achieve fast computations
with a high level of accuracy for large-size engineering problems.
| [
"math.NA",
"cs.LG",
"cs.NA"
] | math.NA | cs.LG | Numerical Analysis;Machine Learning;Numerical Analysis | 5,045Numerical Analysis;Machine Learning;Numerical Analysis
|
2206.04794 | Cyber-physical systems (CPS) are systems where a decision making
(cyber/control) component is tightly integrated with a physical system (with
sensing/actuation) to enable real-time monitoring and control. Recently, there
has been significant research effort in viewing and optimizing physical
infrastructure in built environments as CPS, even if the control action is not
in real-time. Some examples of infrastructure CPS include electrical power
grids; water distribution networks; transportation and logistics networks;
heating, ventilation, and air conditioning (HVAC) in buildings; etc. Complexity
arises in infrastructure CPS from the large scale of operations; heterogeneity
of system components; dynamic and uncertain operating conditions; and
goal-driven decision making and control with time-bounded task completion
guarantees. For control optimization, an infrastructure CPS is typically viewed
as a system of semi-autonomous sub-systems with a network of sensors and uses
distributed control optimization to achieve system-wide objectives that are
typically measured and quantified by better, cheaper, or faster system
performance. In this article, we first illustrate the scope for control
optimization in common infrastructure CPS. Next, we present a brief overview of
current optimization techniques. Finally, we share our research position with a
description of specific optimization approaches and their challenges for
infrastructure CPS of the future.
| [
"eess.SY",
"cs.AI",
"cs.SY"
] | eess.SY | cs.AI | Systems and Control;Artificial Intelligence;Systems and Control | 7,158Systems and Control;Artificial Intelligence;Systems and Control
|
1204.5222 | We obtain a complete classification of hypercomplex manifolds, on which a
compact group of automorphisms acts transitively.
The description of the spaces as well as the proofs of our results use only
the structure theory of reductive groups, in particular the notion of "stem" of
a reduced root system, introduced in the first paper of this series.
| [
"math.DG",
"math.GR"
] | math.DG | math.GR | Differential Geometry;Group Theory | 2,056Differential Geometry;Group Theory
|
1604.00070 | Radiation pressure dominated accretion discs around compact objects may have
turbulent velocities that greatly exceed the electron thermal velocities within
the disc. Bulk Comptonization by the turbulence may therefore dominate over
thermal Comptonization in determining the emergent spectrum. Bulk
Comptonization by divergenceless turbulence is due to radiation viscous
dissipation only. It can be treated as thermal Comptonization by solving the
Kompaneets equation with an equivalent "wave" temperature, which is a weighted
sum over the power present at each scale in the turbulent cascade. Bulk
Comptonization by turbulence with non-zero divergence is due to both pressure
work and radiation viscous dissipation. Pressure work has negligible effect on
photon spectra in the limit of optically thin turbulence, and in this limit
radiation viscous dissipation alone can be treated as thermal Comptonization
with a temperature equivalent to the full turbulent power. In the limit of
extremely optically thick turbulence, radiation viscous dissipation is
suppressed, and the evolution of local photon spectra can be understood in
terms of compression and expansion of the strongly coupled photon and gas
fluids. We discuss the consequences of these effects for self-consistently
resolving and interpreting turbulent Comptonization in spectral calculations in
radiation MHD simulations of high luminosity accretion flows.
| [
"astro-ph.HE"
] | astro-ph.HE | High Energy Astrophysical Phenomena | 2,990High Energy Astrophysical Phenomena
|
|
1409.0160 | Consider the Boltzmann equation in a general non-convex domain with the
diffuse boundary condition. We establish optimal BV estimates for such
solutions. Our method consists of a new $W^{1,1}-$trace estimate for the
diffuse boundary condition and a delicate construction of and an
$\varepsilon-$tubular neighborhood of the singular set.
| [
"math.AP"
] | math.AP | Analysis of PDEs | 205Analysis of PDEs
|
|
2101.06857 | Generalized fusion frame and some of their properties in tensor product of
Hilbert spaces are described. Also, the canonical dual g-fusion frame in tensor
product of Hilbert spaces is considered. Finally, the frame operator for a pair
of g-fusion Bessel sequences in tensor product of Hilbert spaces is presented.
| [
"math.FA"
] | math.FA | Functional Analysis | 2,549Functional Analysis
|
|
1805.00932 | State-of-the-art visual perception models for a wide range of tasks rely on
supervised pretraining. ImageNet classification is the de facto pretraining
task for these models. Yet, ImageNet is now nearly ten years old and is by
modern standards "small". Even so, relatively little is known about the
behavior of pretraining with datasets that are multiple orders of magnitude
larger. The reasons are obvious: such datasets are difficult to collect and
annotate. In this paper, we present a unique study of transfer learning with
large convolutional networks trained to predict hashtags on billions of social
media images. Our experiments demonstrate that training for large-scale hashtag
prediction leads to excellent results. We show improvements on several image
classification and object detection tasks, and report the highest ImageNet-1k
single-crop, top-1 accuracy to date: 85.4% (97.6% top-5). We also perform
extensive experiments that provide novel empirical data on the relationship
between large-scale pretraining and transfer learning performance.
| [
"cs.CV"
] | cs.CV | Computer Vision and Pattern Recognition | 1,498Computer Vision and Pattern Recognition
|
|
physics/0210128 | A thermodynamic analysis of the harmonic oscillator is presented. Motivation
for the study is provided by the blackbody radiation spectrum; when blackbody
radiation is regarded as a system of noninteracting harmonic oscillator modes,
the thermodynamics follows from that of the harmonic oscillators. Using the
behavior of a harmonic oscillator thermodynamic system under a quasi-static
change of oscillator frequency w, we show that the thermodynamic functions can
all be derived from a single function of w/T, analogous to Wien's displacement
theorem. The high- and low-frequency energy limits allow asymptotic energy
forms involving T alone or w alone, corresponding to energy equipartition and
zero-point energy. It is noted that the Planck spectrum with zero-point
radiation corresponds to the function satisfying the Wien displacement result
which provides the smoothest possible interpolation between energy
equipartition at low frequency and zero-point energy at high frequency.
| [
"physics.class-ph",
"physics.gen-ph"
] | physics.class-ph | physics.gen-ph | Classical Physics;General Physics | 993Classical Physics;General Physics
|
2103.12152 | Objective measurement of perceptually motivated music attributes has
application in both target driven mixing and mastering methodologies and music
information retrieval. This work proposes a perceptual model of mix clarity
which decomposes a mixed input signal into transient, steady-state, and
residual components. Masking thresholds are calculated for each component and
their relative relationship is used to determine an overall masking score as
the model's output. Three variants of the model were tested against subjective
mix clarity scores gathered from a controlled listening test. The best
performing variant achieved a Spearman's rank correlation of rho = 0.8382
(p<0.01). Furthermore, the model output was analysed using an independent
dataset generated by progressively applying degradation effects to the test
stimuli. Analysis of the model suggested a close relationship between the
proposed model and the subjective mix clarity scores particularly when masking
was measured using linearly spaced analysis bands. Moreover, the presence of
noise-like residual signals was shown to have a negative effect on the
perceived mix clarity.
| [
"cs.SD",
"eess.AS"
] | cs.SD | eess.AS | Sound;Audio and Speech Processing | 6,734Sound;Audio and Speech Processing
|
1609.09737 | Bulk phase separation is responsible for the occurrence of stacks of
different layers in sedimentation of colloidal mixtures. A recently proposed
theory (de las Heras and Schmidt 2013 Soft Matter 9 8636) establishes a unique
connection between the bulk phase behaviour and
sedimentation-diffusion-equilibrium. The theory constructs a stacking diagram
of all possible sequences of stacks under gravity in the limit of very high
(infinite) sample heights. Here, we study the stacking diagrams of colloidal
mixtures at finite sample height, h. We demonstrate that h plays a vital role
in sedimentation-diffusion-equilibrium of colloidal mixtures. The region of the
stacking diagram occupied by a given sequence of stacks depends on h. Hence,
two samples with different heights but identical colloidal concentrations can
develop different stacking sequences. In addition, the stacking diagrams for
different heights can be qualitatively different since some stacking sequences
occur only in a given interval of sample heights. We use the theory to
investigate the stacking diagrams of both model bulk systems and mixtures of
patchy particles that differ either by the number or by the types of patches.
| [
"cond-mat.soft"
] | cond-mat.soft | Soft Condensed Matter | 6,537Soft Condensed Matter
|
|
1001.3461 | We investigate various limits of the twistor spaces associated to the
self-dual metrics on n CP ^2, the connected sum of the complex projective
planes, constructed by C. LeBrun. In particular, we explicitly present the
following 3 kinds of degenerations whose limits of the metrics are: (a) LeBrun
metrics on (n-1) CP ^2$, (b) (Another) LeBrun metrics on the total space of the
line bundle O(-n) over CP ^1 (c) The hyper-Kaehler metrics on the small
resolution of rational double points of type A_{n-1}, constructed by Gibbons
and Hawking.
| [
"math.DG"
] | math.DG | Differential Geometry | 2,010Differential Geometry
|
|
1705.01298 | Hexagonal boron nitride (hBN) has recently gained a strong interest as a
strategic component in engineering van der Waals heterostructures built with
two dimensional crystals such as graphene. This work reports micro-Raman
measurements on hBN flakes made of a few atomic layers, prepared by mechanical
exfoliation. The temperature dependence of the Raman scattering in hBN is
investigated first such as to define appropriate measurements conditions
suitable for thin layers avoiding undesirable heating induced effects. We
further focus on the low frequency Raman mode corresponding to the rigid
shearing oscillation between adjacent layers, found to be equal to 52.5 cm-1 in
bulk hBN. For hBN sheets with thicknesses below typically 4 nm, the frequency
of this mode presents discrete values, which are found to decrease down to
46.0(5) cm-1 for a three-layer hBN, in good agreement with the linear-chain
model. This makes Raman spectroscopy a relevant tool to quantitatively
determine the number of layers in ultra thin hBN sheets, below 8L.
| [
"cond-mat.mtrl-sci"
] | cond-mat.mtrl-sci | Materials Science | 4,287Materials Science
|
|
2207.09773 | We employ an appropriate perturbative scheme in the large viscous regime to
study oscillating states in driven Langevin systems. We explicitly determine
oscillating state distribution of under-damped Brownian particle subjected to
thermal, viscous and potential drives to linear order in anharmonic
perturbation. We also evaluate various non-equilibrium observables relevant to
characterize the oscillating states. We find that the effects of viscous drive
on oscillating states are measurable even in the leading order and show that
the thermodynamic properties of the system in these states are immensely
distinct from those in equilibrium.
| [
"cond-mat.stat-mech"
] | cond-mat.stat-mech | Statistical Mechanics | 6,821Statistical Mechanics
|
|
1801.01450 | A fundamental problem in object recognition is the development of image
representations that are invariant to common transformations such as
translation, rotation, and small deformations. There are multiple hypotheses
regarding the source of translation invariance in CNNs. One idea is that
translation invariance is due to the increasing receptive field size of neurons
in successive convolution layers. Another possibility is that invariance is due
to the pooling operation. We develop a simple a tool, the
translation-sensitivity map, which we use to visualize and quantify the
translation-invariance of various architectures. We obtain the surprising
result that architectural choices such as the number of pooling layers and the
convolution filter size have only a secondary effect on the
translation-invariance of a network. Our analysis identifies training data
augmentation as the most important factor in obtaining translation-invariant
representations of images using convolutional neural networks.
| [
"cs.CV"
] | cs.CV | Computer Vision and Pattern Recognition | 1,498Computer Vision and Pattern Recognition
|
|
nucl-th/0703021 | The effects of initial-state Coulomb interactions in the
charge-symmetry-breaking reaction dd -> alpha pi^0 are investigated within a
previously published formalism. This is a leading order effect in which the
Coulomb interaction between the two initial state protons leads to the breakup
of the two deuterons into a continuum state that is well connected to the final
alpha pi^0 state by the strong emission of a pion. As a first step, we use a
simplified set of d and alpha wave functions and a plane-wave approximation for
the initial dd state. This Coulomb mechanism, by itself, yields cross sections
that are much larger than the experimental ones, and which are comparable in
size to the contributions from other mechanisms. Inclusion of this mechanism is
therefore necessary in a realistic calculation.
| [
"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
|
0909.2236 | An oscillating electric field at 1.356 GHz was used to promote the resonant
energy transfer process: $43d_{5/2}+43d_{5/2} \to 45p_{3/2}+41f$ between
translationally cold $^{85}$Rb Rydberg atoms. The ac Stark shifts due to this
dressing field created degeneracies between the initial and final two-atom
states of this process. The ac field strength was scanned to collect spectra
which are analogous to dc electric-field-induced resonant energy transfer
spectra. Different resonances were observed for different magnetic sublevels
involved in the process. Compared to earlier work performed at higher
frequencies, the choice of dressing frequency and structure of the spectra may
be intuitively understood, by analogy with the dc field case.
| [
"physics.atom-ph"
] | physics.atom-ph | Atomic Physics | 569Atomic Physics
|
|
1909.12542 | In this paper we derive the maximum entropy characteristics of a particular
rank order distribution, namely the discrete generalized beta distribution,
which has recently been observed to be extremely useful in modelling many
several rank-size distributions from different context in Arts and Sciences, as
a two-parameter generalization of Zipf's law. Although it has been seen to
provide excellent fits for several real world empirical datasets, the
underlying theory responsible for the success of this particular rank order
distribution is not explored properly. Here we, for the first time, provide its
generating process which describes it as a natural maximum entropy distribution
under an appropriate bivariate utility constraint. Further, considering the
similarity of the proposed utility function with the usual logarithmic utility
function from economic literature, we have also explored its acceptability in
universal modeling of different types of socio-economic factors within a
country as well as across the countries. The values of distributional
parameters estimated through a rigorous statistical estimation method, along
with the $entropy$ values, are used to characterize the distributions of all
these socio-economic factors over the years.
| [
"physics.soc-ph",
"physics.data-an",
"q-fin.GN"
] | physics.soc-ph | physics.data-an | Physics and Society;Data Analysis, Statistics and Probability;General Finance | 5,486Physics and Society;Data Analysis, Statistics and Probability;General Finance
|
cs/9809008 | The Asynchronous pi-calculus, as recently proposed by Boudol and,
independently, by Honda and Tokoro, is a subset of the pi-calculus which
contains no explicit operators for choice and output-prefixing. The
communication mechanism of this calculus, however, is powerful enough to
simulate output-prefixing, as shown by Boudol, and input-guarded choice, as
shown recently by Nestmann and Pierce. A natural question arises, then, whether
or not it is possible to embed in it the full pi-calculus. We show that this is
not possible, i.e. there does not exist any uniform, parallel-preserving,
translation from the pi-calculus into the asynchronous pi-calculus, up to any
``reasonable'' notion of equivalence. This result is based on the incapablity
of the asynchronous pi-calculus of breaking certain symmetries possibly present
in the initial communication graph. By similar arguments, we prove a separation
result between the pi-calculus and CCS.
| [
"cs.PL",
"cs.LO"
] | cs.PL | cs.LO | Programming Languages;Logic in Computer Science | 5,816Programming Languages;Logic in Computer Science
|
2309.16891 | We present a proposal for the construction and development of a new
instrument for radio astronomical observations based on interferometric
techniques, that will provide high angular resolution in the 21 cm band, with
the intention of improving and extending the current performance of the
instruments used at the Argentine Institute of Radio Astronomy. This will allow
internationally competitive scientific research and the acquisition of
cutting-edge scientific and technological know-how in the aforementioned
techniques, enabling interferometric measurements and the development of very
long baseline or VLBI techniques. This project is called MIA, an acronym for
"Multipurpose Interferometric Array".
| [
"astro-ph.IM"
] | astro-ph.IM | Instrumentation and Methods for Astrophysics | 3,689Instrumentation and Methods for Astrophysics
|
|
1006.5484 | (abridged) Using a deep Chandra exposure (574 ks), we present high-resolution
thermodynamic maps created from the spectra of $\sim$16,000 independent
regions, each with $\sim$1,000 net counts. The excellent spatial resolution of
the thermodynamic maps reveals the dramatic and complex temperature, pressure,
entropy and metallicity structure of the system. Excluding the 'X-ray arms',
the diffuse cluster gas at a given radius is strikingly isothermal. This
suggests either that the ambient cluster gas, beyond the arms, remains
relatively undisturbed by AGN uplift, or that conduction in the intracluster
medium (ICM) is efficient along azimuthal directions. We confirm the presence
of a thick ($\sim$40 arcsec or $\sim$3 kpc) ring of high pressure gas at a
radius of $\sim$180 arcsec ($\sim$14 kpc) from the central AGN. We verify that
this feature is associated with a classical shock front, with an average Mach
number M = 1.25. Another, younger shock-like feature is observed at a radius of
$\sim$40 arcsec ($\sim$3 kpc) surrounding the central AGN, with an estimated
Mach number M > 1.2. As shown previously, if repeated shocks occur every
$\sim$10 Myrs, as suggested by these observations, then AGN driven weak shocks
could produce enough energy to offset radiative cooling of the ICM. A high
significance enhancement of Fe abundance is observed at radii 350 - 400 arcsec
(27 - 31 kpc). This ridge is likely formed in the wake of the rising bubbles
filled with radio-emitting plasma that drag cool, metal-rich gas out of the
central galaxy. We estimate that at least $\sim1.0\times10^6$ solar masses of
Fe has been lifted and deposited at a radius of 350-400 arcsec; approximately
the same mass of Fe is measured in the X-ray bright arms, suggesting that a
single generation of buoyant radio bubbles may be responsible for the observed
Fe excess at 350 - 400 arcsec.
| [
"astro-ph.CO",
"astro-ph.HE"
] | astro-ph.CO | astro-ph.HE | Cosmology and Nongalactic Astrophysics;High Energy Astrophysical Phenomena | 1,749Cosmology and Nongalactic Astrophysics;High Energy Astrophysical Phenomena
|
1407.5698 | In this paper, we obtain a regularized trace formula for a Sturm Liouville
problem which has two points of discontinuity and also contains an
eigenparameter in a boundary ondition.
| [
"math.CA"
] | math.CA | Classical Analysis and ODEs | 934Classical Analysis and ODEs
|
|
1309.1845 | The broken symmetry state with off-diagonal long-range order (ODLRO), which
is characterized by the vacuum expectation value of the operator of creation of
the conserved quantum number Q, has the time-dependent order parameter.
However, the breaking of the time reversal symmetry is observable only if the
charge Q is not strictly conserved and may decay. This dihotomy is resolved in
systems with quasi-ODLRO. These systems have two well separated relaxation
times: the relaxation time \tau_Q of the charge Q and the energy relaxation
time \tau_E. If \tau_Q >> \tau_E, the perturbed system relaxes first to the
state with the ODLRO, which persists for a long time \tau_Q and finally relaxes
to the full equilibrium static state. In the limit \tau_Q -> \infty, but not in
the strict limit case when the charge Q is conserved, the intermediate ODLRO
state can be considered as the ground state of the system at fixed Q with the
observable spontaneously broken time reversal symmetry. Examples of systems
with quasi-ODLRO are provided by superfluid phase of liquid 4He, Bose-Einstein
condensation of magnons (phase coherent spin precession) and precessing
vortices.
| [
"cond-mat.other",
"hep-ph"
] | cond-mat.other | hep-ph | Other Condensed Matter;High Energy Physics - Phenomenology | 5,376Other Condensed Matter;High Energy Physics - Phenomenology
|
cond-mat/9706206 | The influence of disordering upon critical behavior of the system with hidden
degrees of freedom is considered. It is shown that there is a tricritical
behavior in the constrained system, while in the unconstrained system only
phase transitions of the second order occur.
| [
"cond-mat.dis-nn",
"cond-mat.stat-mech"
] | cond-mat.dis-nn | cond-mat.stat-mech | Disordered Systems and Neural Networks;Statistical Mechanics | 2,174Disordered Systems and Neural Networks;Statistical Mechanics
|
2206.00409 | In this paper, we consider a wide class of time-varying multivariate causal
processes which nests many classic and new examples as special cases. We first
prove the existence of a weakly dependent stationary approximation for our
model which is the foundation to initiate the theoretical development.
Afterwards, we consider the QMLE estimation approach, and provide both
point-wise and simultaneous inferences on the coefficient functions. In
addition, we demonstrate the theoretical findings through both simulated and
real data examples. In particular, we show the empirical relevance of our study
using an application to evaluate the conditional correlations between the stock
markets of China and U.S. We find that the interdependence between the two
stock markets is increasing over time.
| [
"econ.EM"
] | econ.EM | Econometrics | 2,397Econometrics
|
|
1712.05829 | Injection of coaxial-gun-formed magnetized plasmas into a background
transverse vacuum magnetic field or into a background magnetized plasma has
been studied in the helicon-cathode (HelCat) linear plasma device at the
University of New Mexico [M. Gilmore et al., J. Plasma Phys.81, 345810104
(2015)]. Magnetized plasma jet launched into a background transverse magnetic
field shows emergent kink stabilization of the jet due to the formation of a
sheared flow in the jet above the kink-stabilization threshold $0.1kV_A$ [Y.
Zhang et al., Phys. Plasmas 24, 110702 (2017)]. Injection of a spheromak-like
plasma into a transverse background magnetic field led to the observation of
finger-like structures on the side with a stronger magnetic field null between
the spheromak and background field. The finger-like structures are consistent
with magneto-Rayleigh-Taylor instability. Jets or spheromaks launched into a
background, low-$\beta$ magnetized plasma show similar behavior as above,
respectively, in both cases.
| [
"physics.plasm-ph"
] | physics.plasm-ph | Plasma Physics | 5,556Plasma Physics
|
|
2307.02643 | A restricted form of Landauer's Principle, independent of computational
considerations, is shown to hold for thermal systems by reference to the joint
entropy associated with conjugate observables. It is shown that the source of
the compensating entropy for irreversible physical processes is due to the
ontological uncertainty attending values of such mutually incompatible
observables, rather than due to epistemic uncertainty as traditionally assumed
in the information-theoretic approach. In particular, it is explicitly shown
that erasure of logical (epistemic) information via reset operations is not
equivalent to erasure of thermodynamic entropy, so that the traditional,
information-theoretic form of Landauer's Principle is not supported by the
physics. A further implication of the analysis is that there is no Maxwell's
Demon in the real world.
| [
"quant-ph",
"physics.hist-ph"
] | quant-ph | physics.hist-ph | Quantum Physics;History and Philosophy of Physics | 6,095Quantum Physics;History and Philosophy of Physics
|
cond-mat/0404279 | We study the ground state properties of a quantum antiferromagnet on the
kagome lattice in the presence of a magnetic field, paying particular attention
to the stability of the plateau at magnetization 1/3 of saturation and the
nature of its ground state. We discuss fluctuations around classical ground
states and argue that quantum and classical calculations at the harmonic level
do not lead to the same result in contrast to the zero-field case. For spin
S=1/2 we find a magnetic gap below which an exponential number of non-magnetic
excitations are present. Moreover, such non-magnetic excitations also have a
(much smaller) gap above the three-fold degenerate ground state. We provide
evidence that the ground state has long-range order of valence-bond crystal
type with nine spins in the unit cell.
| [
"cond-mat.str-el",
"cond-mat.stat-mech"
] | cond-mat.str-el | cond-mat.stat-mech | Strongly Correlated Electrons;Statistical Mechanics | 7,046Strongly Correlated Electrons;Statistical Mechanics
|
astro-ph/0502283 | In this letter, we discuss generation of magnetic field from cosmological
perturbations. We consider the evolution of three component plasma (electron,
proton and photon) evaluating the collision term between elecrons and photons
up to the second order. The collision term is shown to induce electric current,
which then generate magnetic field. There are three contributions, two of which
can be evaluated from the first-order quantities, while the other one is fluid
vorticity which is purely second order. We estimate the magnitudes of the
former contributions and shows that the amplitude of the produced magnetic
field is about $\sim 10^{-19} {\rm G}$ at 10Mpc comoving scale at the
recombination. Compared to astrophysical and inflationary mechanisms for
seed-field generation, our study suffers from much less ambiguities concerning
unknown physics and/or processes.
| [
"astro-ph"
] | astro-ph | Astrophysics | 463Astrophysics
|
|
2204.03669 | We consider the setup of an evaporating black hole in AdS$_{4}$ coupled to an
external bath, embedded in type IIB string theory. We study quantum extremal
islands in these backgrounds, in relation to the existence of a massive
graviton. Using explicit results of the microscopic embedding of AdS$_{4}$
massive gravity in string theory, we investigate whether it is possible to
achieve backgrounds with extremal islands, in which the lowest lying graviton
is only slightly massive. For certain regions of the microscopic parameters,
the graviton mass can be computed explicitly, and we explain how it directly
affects the existence and the properties of the islands. We also show that
islands can in principle exist within the regime of validity of the massive
gravity effective field theory. However we see via numerical computations that
the existence of quantum extremal islands at zero temperature is highly
constrained, also when the dilaton is allowed to vary, so that the mass of the
graviton cannot be made arbitrarily light. At finite temperature, we also
identify a critical parameter, above and below which islands still exist but
exhibit a different behavior. Our work supports recent proposals that the
unitary evolution of black holes in higher dimensions, and more precisely their
Page curve, strongly relies on the presence of a massive graviton in the
effective theory.
| [
"hep-th"
] | hep-th | High Energy Physics - Theory | 3,266High Energy Physics - Theory
|
|
2305.03150 | Biomolecular condensates constitute a newly recognized form of spatial
organization in living cells. Although many condensates are believed to form as
a result of phase separation, the physicochemical properties that determine the
phase behavior of heterogeneous biomolecular mixtures are only beginning to be
explored. Theory and simulation provide invaluable tools for probing the
relationship between molecular determinants, such as protein and RNA sequences,
and the emergence of phase-separated condensates in such complex environments.
This review covers recent advances in the prediction and computational design
of biomolecular mixtures that phase-separate into many coexisting phases.
First, we review efforts to understand the phase behavior of mixtures with
hundreds or thousands of species using theoretical models and statistical
approaches. We then describe progress in developing analytical theories and
coarse-grained simulation models to predict multiphase condensates with the
molecular detail required to make contact with biophysical experiments. We
conclude by summarizing the challenges ahead for modeling the inhomogeneous
spatial organization of biomolecular mixtures in living cells.
| [
"physics.bio-ph",
"cond-mat.soft",
"q-bio.BM"
] | physics.bio-ph | cond-mat.soft | Biological Physics;Soft Condensed Matter;Biomolecules | 713Biological Physics;Soft Condensed Matter;Biomolecules
|
1901.07265 | Internet-wide scans are a common active measurement approach to study the
Internet, e.g., studying security properties or protocol adoption. They involve
probing large address ranges (IPv4 or parts of IPv6) for specific ports or
protocols. Besides their primary use for probing (e.g., studying protocol
adoption), we show that - at the same time - they provide valuable insights
into the Internet control plane informed by ICMP responses to these probes - a
currently unexplored secondary use. We collect one week of ICMP responses
(637.50M messages) to several Internet-wide ZMap scans covering multiple TCP
and UDP ports as well as DNS-based scans covering > 50% of the domain name
space. This perspective enables us to study the Internet's control plane as a
by-product of Internet measurements. We receive ICMP messages from ~171M
different IPs in roughly 53K different autonomous systems. Additionally, we
uncover multiple control plane problems, e.g., we detect a plethora of outdated
and misconfigured routers and uncover the presence of large-scale persistent
routing loops in IPv4.
| [
"cs.NI"
] | cs.NI | Networking and Internet Architecture | 4,711Networking and Internet Architecture
|
|
1603.02908 | We present a method that can be used to recover the spectrum of turbulence
from observations of optically thin emission lines formed in astrophysical
disks. Within this method we analyze how line intensity fluctuations depend on
the angular resolution of the instrument, used for the observations. The method
allows us to restore the slope of the power spectrum of velocity turbulent
pulsations and estimate the upper boundary of the turbulence scale.
| [
"astro-ph.IM"
] | astro-ph.IM | Instrumentation and Methods for Astrophysics | 3,689Instrumentation and Methods for Astrophysics
|
|
hep-th/0505243 | We study the Penrose limit about a null geodesic with 3 equal angular momenta
in the recently obtained type IIB solution dual to an exactly marginal
$\gamma$-deformation of N=4 SYM. The resulting background has non-trivial NS
3-form flux as well as RR 5- and 3-form fluxes. We quantise the light-cone
Green-Schwarz action and show that it exhibits a continuum spectrum. We show
that this is related to the dynamics of a charged particle moving in a Landau
plane with an extra interaction induced by the deformation. We interpret the
results in the dual N=1 SCFT.
| [
"hep-th"
] | hep-th | High Energy Physics - Theory | 3,266High Energy Physics - Theory
|
|
1111.6588 | Extremely low mass (ELM) white dwarfs (WDs) with masses <0.25 Msun are rare
objects that result from compact binary evolution. Here, we present a targeted
spectroscopic survey of ELM WD candidates selected by color. The survey is 71%
complete and has uncovered 18 new ELM WDs. Of the 7 ELM WDs with follow-up
observations, 6 are short-period binaries and 4 have merger times less than 5
Gyr. The most intriguing object, J1741+6526, likely has either a pulsar
companion or a massive WD companion making the system a possible supernova Type
Ia or .Ia progenitor. The overall ELM Survey has now identified 19 double
degenerate binaries with <10 Gyr merger times. The significant absence of short
orbital period ELM WDs at cool temperatures suggests that common envelope
evolution creates ELM WDs directly in short period systems. At least one-third
of the merging systems are halo objects, thus ELM WD binaries continue to form
and merge in both the disk and the halo.
| [
"astro-ph.SR",
"astro-ph.GA"
] | astro-ph.SR | astro-ph.GA | Solar and Stellar Astrophysics;Astrophysics of Galaxies | 6,669Solar and Stellar Astrophysics;Astrophysics of Galaxies
|
1910.14177 | We consider a class of Cahn-Hilliard equation that models phase separation
process of binary mixtures involving nontrivial boundary interactions in a
bounded domain with non-permeable wall. The system is characterized by certain
dynamic type boundary conditions and the total mass, in the bulk and on the
boundary, is conserved for all time. For the case with physically relevant
singular (e.g., logarithmic) potential, global regularity of weak solutions is
established. In particular, when the spatial dimension is two, we show the
instantaneous strict separation property such that for arbitrary positive time
any weak solution stays away from the pure phases +1 and -1, while in the three
dimensional case, an eventual separation property for large time is obtained.
As a consequence, we prove that every global weak solution converges to a
single equilibrium as the time goes to infinity, by the usage of an extended
Lojasiewicz-Simon inequality.
| [
"math.AP"
] | math.AP | Analysis of PDEs | 205Analysis of PDEs
|
|
2204.04942 | In this paper we give an overview of some recent and older results concerning
free boundary problems governed by elliptic operators.
| [
"math.AP"
] | math.AP | Analysis of PDEs | 205Analysis of PDEs
|
|
1812.02928 | Recently there has been considerable progress on the analysis of stability
and performance properties of so-called economic Nonlinear Model Predictive
Control (NMPC) schemes; i.e. NMPC schemes employing stage costs that are not
directly related to distance measures of pre-computed setpoints. At the same
time, with respect to the energy transition, the use of NMPC schemes is
proposed and investigated in a plethora of papers in different contexts. For
example receding-horizon approaches to generator dispatch problems, which is
also known as multi-stage Optimal Power Flow (OPF), naturally lead to economic
NMPC schemes based on non-convex discrete-time Optimal Control Problems (OCP).
The present paper investigates the transfer of analytic results available for
general economic NMPC schemes to receding-horizon multistage OPF. We propose a
blueprint formulation of multi-stage opf including AC power flow equations.
Based on this formulation we present results on the dissipativity and recursive
feasibility properties of the underlying OCP. Finally, we draw upon simulations
using a 5 bus system and a 118 bus system to illustrate our findings.
| [
"cs.SY"
] | cs.SY | Systems and Control | 7,149Systems and Control
|
|
2108.11311 | This paper presents a novel adaptive fading cubature Kalman filter (AFCKF)
based on double transitive factors. The developed adaptive algorithm is
explained in two stages; stage (i) a single transitive factor is used to update
the predicted state error covariance, ${\bf \hat P_{k}}^{-}$ based on
innovation or residual vector, whereas, in stage (ii), the measurement noise
covariance matrix, ${\bf \hat R_{k}^{*}}$ is scaled by another transitive
factor. Furthermore, showing the proof concept for estimation of the process
noise, ${\bf \hat Q_{k}^{*}}$ and measurement noise covariance matrices by
combining the innovation and residual vector in the AFCKF algorithm. It can
provide reliable state estimation in the presence of unknown noise statistics.
Bench-marking target tracking example is considered to show the performance
improvement of the developed algorithms. As compared with existing adaptive
approaches, the proposed fading algorithm can provide better estimation
results.
| [
"eess.SY",
"cs.SY",
"eess.SP"
] | eess.SY | cs.SY | Systems and Control;Systems and Control;Signal Processing | 7,233Systems and Control;Systems and Control;Signal Processing
|
1007.2321 | The luminescence caused by the interband transitions of hot carriers in
graphene is considered theoretically. The dependencies of emission in mid- and
near-IR spectral regions versus energy and concentration of hot carriers are
analyzed; they are determined both by an applied electric field and a gate
voltage. The polarization dependency is determined by the angle between the
propagation direction and the normal to the graphene sheet. The characteristics
of radiation from large-scale-area samples of epitaxial graphene and from
microstructures of exfoliated graphene are considered. The averaged over angles
efficiency of emission is also presented.
| [
"cond-mat.mes-hall",
"cond-mat.mtrl-sci"
] | cond-mat.mes-hall | cond-mat.mtrl-sci | Mesoscale and Nanoscale Physics;Materials Science | 4,493Mesoscale and Nanoscale Physics;Materials Science
|
1509.03144 | We propose and experimentally verify a cooling limit for a quantum channel
going through an incoherent environment. The environment consists of a large
number of independent non-interacting and non-interfering elementary quantum
systems - qubits. The qubits travelling through the channel can only be
randomly replaced by environmental qubits. We investigate a conditional cooling
limit that exploits an additional probing output. The limit specifies when the
single-qubit channel is quantum, i.e. it preserves entanglement. It is a
fundamental condition for entanglement-based quantum technology.
| [
"quant-ph"
] | quant-ph | Quantum Physics | 5,985Quantum Physics
|
|
quant-ph/0410149 | We propose and study an active cooling mechanism for the nanomechanical
resonator (NAMR) based on periodical coupling to a Cooper pair box (CPB), which
is implemented by a designed series of magnetic flux pluses threading through
the CPB. When the initial phonon number of the NAMR is not too large, this
cooling protocol is efficient in decreasing the phonon number by two to three
orders of magnitude. Our proposal is theoretically universal in cooling various
boson systems of single mode. It can be specifically generalized to prepare the
nonclassical state of the NAMR.
| [
"quant-ph"
] | quant-ph | Quantum Physics | 5,985Quantum Physics
|
|
0807.2495 | We studied a metasurface constituted as a periodic array of semiconductor
split-ring resonators. The resonance frequencies of the metasurface excited by
normally incident light were found to be continuously tunable in the terahertz
regime through an external magnetostatic field of suitable orientation. As such
metasurfaces can be assembled into 3D metamaterials, the foregoing conclusion
also applies to metamaterials comprising semiconductor split-ring resonators.
| [
"cond-mat.mtrl-sci",
"cond-mat.other",
"physics.optics"
] | cond-mat.mtrl-sci | cond-mat.other | Materials Science;Other Condensed Matter;Optics | 4,359Materials Science;Other Condensed Matter;Optics
|
1801.01468 | We present a novel inertial-isolation scheme based on six degree-of-freedom
(6D) interferometric sensing of a single reference mass. It is capable of
reducing inertial motion by more than two orders of magnitude at 100\,mHz
compared with what is achievable with state-of-the-art seismometers. This will
enable substantial improvements in the low-frequency sensitivity of
gravitational-wave detectors. The scheme is inherently two-stage, the reference
mass is softly suspended within the platform to be isolated, which is itself
suspended from the ground. The platform is held constant relative to the
reference mass and this closed-loop control effectively transfers the low
acceleration-noise of the reference mass to the platform. A high loop gain also
reduces non-linear couplings and dynamic range requirements in the
soft-suspension mechanics and the interferometric sensing.
| [
"astro-ph.IM",
"gr-qc",
"physics.ins-det"
] | astro-ph.IM | gr-qc | Instrumentation and Methods for Astrophysics;General Relativity and Quantum Cosmology;Instrumentation and Detectors | 3,734Instrumentation and Methods for Astrophysics;General Relativity and Quantum Cosmology;Instrumentation and Detectors
|
1304.3915 | We describe a non-parametric, "example-based" method for estimating the depth
of an object, viewed in a single photo. Our method consults a database of
example 3D geometries, searching for those which look similar to the object in
the photo. The known depths of the selected database objects act as shape
priors which constrain the process of estimating the object's depth. We show
how this process can be performed by optimizing a well defined target
likelihood function, via a hard-EM procedure. We address the problem of
representing the (possibly infinite) variability of viewing conditions with a
finite (and often very small) example set, by proposing an on-the-fly example
update scheme. We further demonstrate the importance of non-stationarity in
avoiding misleading examples when estimating structured shapes. We evaluate our
method and present both qualitative as well as quantitative results for
challenging object classes. Finally, we show how this same technique may be
readily applied to a number of related problems. These include the novel task
of estimating the occluded depth of an object's backside and the task of
tailoring custom fitting image-maps for input depths.
| [
"cs.CV"
] | cs.CV | Computer Vision and Pattern Recognition | 1,498Computer Vision and Pattern Recognition
|
|
1402.5322 | Ionization injection triggered by short wavelength laser pulses inside a
nonlinear wakefield driven by a longer wavelength laser is examined via
multi-dimensional particle-in-cell simulations. We find that very bright
electron beams can be generated through this two-color scheme in either
collinear propagating or transverse colliding geometry. For a fixed laser
intensity $I$, lasers with longer/shorter wavelength $\lambda$ have
larger/smaller ponderomotive potential ($\propto I \lambda^2$). The two color
scheme utilizes this property to separate the injection process from the
wakefield excitation process. Very strong wakes can be generated at relatively
low laser intensities by using a longer wavelength laser driver (e.g. a $10
\micro\meter$ CO$_2$ laser) due to its very large ponderomotive potential. On
the other hand, short wavelength laser can produce electrons with very small
residual momenta ($p_\perp\sim a_0\sim \sqrt{I}\lambda$) inside the wake,
leading to electron beams with very small normalized emittances (tens of
$\nano\meter$). Using particle-in-cell simulations we show that a $\sim10
\femto\second$ electron beam with $\sim4 \pico\coulomb$ of charge and a
normalized emittance of $\sim 50 \nano\meter$ can be generated by combining a
10 $\micro\meter $ driving laser with a 400 $\nano\meter$ injection laser,
which is an improvement of more than one order of magnitude compared to the
typical results obtained when a single wavelength laser used for both the wake
formation and ionization injection.
| [
"physics.acc-ph",
"physics.plasm-ph"
] | physics.acc-ph | physics.plasm-ph | Accelerator Physics;Plasma Physics | 20Accelerator Physics;Plasma Physics
|
cond-mat/0211651 | We report the observation of nonexponential decay of pulsed microwave
transmission through quasi-one-dimensional random dielectric media that signals
the breakdown of the diffusion model of transport for temporally coherent
extended waves. The decay rate of transmission falls nearly linearly in time
due to a nearly gaussian distribution of the coupling strengths of quasi-normal
electromagnetic modes to free space at the sample surfaces. The peak and width
of this distribution scale as L^{-2.05} and L^{-1.81}, respectively.
| [
"cond-mat.dis-nn"
] | cond-mat.dis-nn | Disordered Systems and Neural Networks | 2,129Disordered Systems and Neural Networks
|
|
1710.05171 | We explore the effects of disordered charged defects on the electronic
excitations observed in the photoemission spectra of doped transition metal
oxides in the Mott insulating regime by the example of the
$R_{1-x}$Ca$_x$VO$_3$ perovskites, where $R=$La,$\dots$,Lu. A fundamental
characteristic of these vanadium $d^2$ compounds with partly filled $t_{2g}$
valence orbitals is the persistence of spin and orbital order up to high
doping, in contrast to the loss of magnetic order in high-$T_c$ cuprates at low
defect concentration. We demonstrate that the disordered electronic structure
of doped Mott-Hubbard insulators can be obtained with high precision within the
unrestricted Hartree-Fock approximation. In particular: (i) the atomic
multiplet excitations in the inverse photoemission spectra and the various
defect-related states and satellites are well reproduced, (ii) a robust Mott
gap survives up to large doping, and (iii) we show that the defect states
inside the Mott gap develop a soft gap at the Fermi energy. The soft defect
states gap can be characterized by a shape and a scale parameter extracted from
a Weibull statistical sampling of the density of states near the chemical
potential. We demonstrate that charge defects trigger small spin-orbital
polarons, with their internal kinetic energy responsible for the opening of the
soft defect states gap. The small size of spin-orbital polarons is inferred by
an analysis of the inverse participation ratio which explains the origin of the
robustness of spin and orbital order. Using realistic parameters for
La$_{1-x}$Ca$_x$VO$_3$, we show that its soft gap is well reproduced as well as
the marginal doping dependence of the position of the chemical potential
relative to the center of the lower Hubbard band.
| [
"cond-mat.str-el",
"cond-mat.mtrl-sci"
] | cond-mat.str-el | cond-mat.mtrl-sci | Strongly Correlated Electrons;Materials Science | 7,006Strongly Correlated Electrons;Materials Science
|
hep-ph/9702422 | We calculate, in chiral perturbation theory, the change in the self-energy of
decuplet baryons in nuclear matter. These self-energy shifts are relevant in
studies of meson-nucleus scattering and of neutron stars. Our results are
leading order in an expansion in powers of the ratio of characteristic momenta
to the chiral symmetry-breaking scale (or the nucleon mass). Included are
contact diagrams generated by 4-baryon operators, which were neglected in
earlier studies for the $\Delta$ isomultiplet but contribute to the self-energy
shifts at this order in chiral perturbation theory.
| [
"hep-ph"
] | hep-ph | High Energy Physics - Phenomenology | 3,129High Energy Physics - Phenomenology
|
|
0909.4192 | Low $L_{FIR}$ Isolated Galaxies (IGs) from the AMIGA sample have low level of
Star Formation (SF) activity. We observed the HCN(1-0) emission in a sample of
IGs in order to test whether they follow the tight relation between $L_{HCN}$
and $L_{FIR}$ found for galaxies with more active SF.
| [
"astro-ph.CO"
] | astro-ph.CO | Cosmology and Nongalactic Astrophysics | 1,725Cosmology and Nongalactic Astrophysics
|
|
nucl-th/9602016 | We present a model for dilepton production of proton-proton collisions using
a realist T-matrix that by incorporating Delta-isobar degrees of freedom fits
the NN-scattering data up to 2 GeV. The results we find differ in details from
earlier work that use less sophisticated interactions but the overall agreement
with these calculations is good.
| [
"nucl-th"
] | nucl-th | Nuclear Theory | 4,876Nuclear Theory
|
|
2312.08277 | Galaxy clusters are important probes for both cosmology and galaxy formation
physics. We test the cosmological, hydrodynamical FLAMINGO simulations by
comparing to observations of the gaseous properties of clusters measured from
X-ray observations. FLAMINGO contains unprecedented numbers of massive galaxy
groups ($>10^6$) and clusters ($>10^5$) and includes variations in both
cosmology and galaxy formation physics. We predict the evolution of cluster
scaling relations as well as radial profiles of the temperature, density,
pressure, entropy, and metallicity for different masses and redshifts. We show
that the differences between volume-, and X-ray-weighting of particles in the
simulations, and between cool-core non cool-core samples, are similar in size
as the differences between simulations for which the stellar and AGN feedback
has been calibrated to produce significantly different gas fractions. Compared
to thermally-driven AGN feedback, kinetic jet feedback calibrated to produce
the same gas fraction at $R_{\rm 500c}$ yields a hotter core with higher
entropies and lower densities, which translates into a smaller fraction of
cool-core clusters. Stronger feedback, calibrated to produce lower gas
fractions and hence lower gas densities, results in higher temperatures,
entropies, and metallicities, but lower pressures. The scaling relations and
thermodynamic profiles show almost no evolution with respect to self-similar
expectations, except for the metallicity decreasing with redshift. We find that
the temperature, density, pressure, and entropy profiles of clusters in the
fiducial FLAMINGO simulation are in excellent agreement with observations,
while the metallicities in the core are too high.
| [
"astro-ph.GA",
"astro-ph.CO"
] | astro-ph.GA | astro-ph.CO | Astrophysics of Galaxies;Cosmology and Nongalactic Astrophysics | 470Astrophysics of Galaxies;Cosmology and Nongalactic Astrophysics
|
1806.09896 | This paper presents a new modeling strategy for joint unsupervised analysis
of multiple high-throughput biological studies. As in Multi-study Factor
Analysis, our goals are to identify both common factors shared across studies
and study-specific factors. Our approach is motivated by the growing body of
high-throughput studies in biomedical research, as exemplified by the
comprehensive set of expression data on breast tumors considered in our case
study. To handle high-dimensional studies, we extend Multi-study Factor
Analysis using a Bayesian approach that imposes sparsity. Specifically, we
generalize the sparse Bayesian infinite factor model to multiple studies. We
also devise novel solutions for the identification of the loading matrices: we
recover the loading matrices of interest ex-post, by adapting the orthogonal
Procrustes approach. Computationally, we propose an efficient and fast Gibbs
sampling approach. Through an extensive simulation analysis, we show that the
proposed approach performs very well in a range of different scenarios, and
outperforms standard Factor analysis in all the scenarios identifying
replicable signal in unsupervised genomic applications. The results of our
analysis of breast cancer gene expression across seven studies identified
replicable gene patterns, clearly related to well-known breast cancer pathways.
An R package is implemented and available on GitHub.
| [
"stat.AP"
] | stat.AP | Applications | 276Applications
|
|
1005.2268 | This paper considers the state of nuclear and radiological security in the UK
and abroad and reports on the methods that could be employed by terrorists with
radiological or nuclear material to cause destruction. It is shown that despite
current safeguards that problems arise due to materials that are unaccounted
for and poor implementation of detection regimes in some geographical regions.
The prospect of a future terrorist event that involves nuclear or radiological
materials seems likely despite best efforts of prevention.
| [
"physics.soc-ph"
] | physics.soc-ph | Physics and Society | 5,463Physics and Society
|
|
2202.06228 | Recent advances in deep learning have led to substantial improvements in
deepfake generation, resulting in fake media with a more realistic appearance.
Although deepfake media have potential application in a wide range of areas and
are drawing much attention from both the academic and industrial communities,
it also leads to serious social and criminal concerns. This chapter explores
the evolution of and challenges in deepfake generation and detection. It also
discusses possible ways to improve the robustness of deepfake detection for a
wide variety of media (e.g., in-the-wild images and videos). Finally, it
suggests a focus for future fake media research.
| [
"cs.CV"
] | cs.CV | Computer Vision and Pattern Recognition | 1,498Computer Vision and Pattern Recognition
|
|
2304.01946 | This paper develops a polyhedral approach to the design, analysis, and
computation of dynamic allocation indices for scheduling binary-action
(engage/rest) Markovian stochastic projects which can change state when rested
(restless bandits (RBs)), based on partial conservation laws (PCLs). This
extends previous work by the author [J. Ni\~no-Mora. Restless bandits, partial
conservation laws and indexability. Adv. Appl. Probab., vol. 33, 76-98, 2001],
where PCLs were shown to imply optimality of index policies with a postulated
structure under admissible linear objectives, and they were deployed to obtain
sufficient conditions for the existence of Whittle's index and an
adaptive-greedy index algorithm. The contributions include: (i) we develop the
polyhedral foundation of the PCL framework, based on structural and algorithmic
properties of a polytope associated with an accessible set system
($\mathcal{F}$-extended polymatroid); (ii) we present new indices for RBs,
motivated by an admission control model, which extend Whittle's and have a
significantly increased scope; (iii) we deploy PCLs to obtain both sufficient
conditions for the existence of the new indices (PCL-indexability) and a
reformulated adaptive-greedy index algorithm; (iv) we interpret
PCL-indexability in terms of the economic law of diminishing marginal returns
and characterize the index as an optimal marginal cost rate; (v) we carry out a
PCL-indexability analysis of the motivating admission control model, which
gives, under mild conditions, a new index characterization of optimal threshold
policies; and (vi) we apply the latter to present new heuristic index policies
for two hard queueing control problems: admission control and routing to
parallel queues; and scheduling a multiclass make-to-stock queue with lost
sales, both under state-dependent holding cost rates and birth-death dynamics.
| [
"math.OC",
"math.PR"
] | math.OC | math.PR | Optimization and Control;Probability | 5,331Optimization and Control;Probability
|
1508.01120 | The effective potential $\Phi$ of a classical ion in a weakly correlated
quantum plasma in thermodynamic equilibrium at finite temperature is well
described by the RPA screened Coulomb potential. Additionally, collision
effects can be included via a relaxation time ansatz (Mermin dielectric
function). These potentials are used to study the quality of various statically
screened potentials that were recently proposed by Shukla and Eliasson (SE)
[Phys. Rev. Lett. {\bf 108}, 165007 (2012)], Akbari--Moghanjoughi (AM) [Phys.
Plasmas {\bf 22}, 022103 (2015)] and Stanton and Murillo (SM) [Phys. Rev. E
{\bf 91}, 033104 (2015)] starting from quantum hydrodynamic theory (QHD). Our
analysis reveals that the SE potential is qualitatively different from the full
potential, whereas the SM potential (at any temperature) and the AM potential
(at zero temperature) are significantly more accurate. This confirms the
correctness of the recently derived [Michta {\em et al.}, Contrib. Plasma Phys.
{\bf 55}, (2015)] pre-factor $1/9$ in front of the Bohm term of QHD for
fermions.
| [
"physics.plasm-ph"
] | physics.plasm-ph | Plasma Physics | 5,556Plasma Physics
|
|
1410.1398 | The numerical conditions to generate a high-fidelity Yurke-Stoler states
($|\alpha>+ e^{i \psi} |-\alpha>$)were found for two cascade-placed beam
splitters with one squeezed state input and two coherent state inputs.
Controlling the amplitude and the phases of beams, allows for various
Yurke-Stoler states to be manipulated with ultra high-fidelity, and the
expected theoretical fidelity is of more than 0.9999.
| [
"physics.optics",
"quant-ph"
] | physics.optics | quant-ph | Optics;Quantum Physics | 5,227Optics;Quantum Physics
|
2008.09329 | The $2$-layer drawing model is a well-established paradigm to visualize
bipartite graphs. Several beyond-planar graph classes have been studied under
this model. Surprisingly, however, the fundamental class of $k$-planar graphs
has been considered only for $k=1$ in this context. We provide several
contributions that address this gap in the literature. First, we show tight
density bounds for the classes of $2$-layer $k$-planar graphs with
$k\in\{2,3,4,5\}$. Based on these results, we provide a Crossing Lemma for
$2$-layer $k$-planar graphs, which then implies a general density bound for
$2$-layer $k$-planar graphs. We prove this bound to be almost optimal with a
corresponding lower bound construction. Finally, we study relationships between
$k$-planarity and $h$-quasiplanarity in the $2$-layer model and show that
$2$-layer $k$-planar graphs have pathwidth at most $k+1$.
| [
"cs.DM",
"cs.CG",
"cs.DS"
] | cs.DM | cs.CG | Discrete Mathematics;Computational Geometry;Data Structures and Algorithms | 7,267longtail
|
0807.3946 | Four-photon scattering in nonlinear waveguides is an important physical
process that allows photon-pair generation in well defined guided modes, with
high rate and reasonably low noise. Most of the experiments to date used the
scalar four-photon scattering process in which the pump photons and the
scattered photons have the same polarization. In birefringent waveguides,
vectorial four-photon scattering is also allowed: these vectorial scattering
processes involve photons with different polarizations. In this article, the
theory of four-photon scattering in nonlinear, birefringent, and dispersive
fibers is developed in the framework of the quantum theory of light. The work
focusses on the spectral properties and quantum correlations (including
entanglement) of photon-pairs generated in high-birefringence and
low-birefringence fibers.
| [
"quant-ph"
] | quant-ph | Quantum Physics | 5,985Quantum Physics
|
|
2308.09551 | In 1984, Charney and Lee defined a category of stable curves and exhibited a
rational homology equivalence from its geometric realisation to (the
analytification of) the moduli stack of stable curves, also known as the
Deligne-Mumford-Knudsen compactification. We strengthen this result by showing
that, in fact, this category captures the stratified homotopy type of the
moduli stack. In particular, it classifies constructible sheaves via an
exodromy equivalence.
| [
"math.AG",
"math.AT",
"math.GT"
] | math.AG | math.AT | Algebraic Geometry;Algebraic Topology;Geometric Topology | 56Algebraic Geometry;Algebraic Topology;Geometric Topology
|