id
stringlengths 9
16
| abstract
stringlengths 67
2.61k
| cats
sequence | primary
stringlengths 5
18
| secondary
stringlengths 0
18
| strlabel
stringlengths 5
315
| stratlabel
class label 7.27k
classes |
|---|---|---|---|---|---|---|
cond-mat/0307627 | Neutron and x-ray powder diffraction have been used to investigate the
crystal structures of a sample of the newly-discovered superconducting sodium
cobaltate deuterate compound with composition Na0.31(3)CoO2o1.25(2)D2O and its
anhydrous parent compound Na0.61(1)CoO2. The deuterate superconducting compound
is formed by coordinating four D2O molecules (two above and two below) to each
Na ion in a way that gives Na-O distances nearly equal to those in the parent
compound. One deuteron of the D2O molecule is hydrogen bonded to an oxygen atom
in the CoO2 plane and the oxygen atom and the second deuteron of each D2O
molecule lie approximately in a plane between the Na layer and the CoO2 layers.
This coordination of Na by four D2O molecules leads to ordering of the Na ions
and D2O molecules. The sample studied here, which has Tc=4.5 K, has a refined
composition of Na0.31(3)CoO2o1.25(2)D2O, in agreement with the expected 1:4
ratio of Na to D2O. These results show that the optimal superconducting
composition should be viewed as a specific hydrated compound, not a solid
solution of Na and D2O (H2O) in NaxCoO2oyD2O. Studies of physical properties
vs. Na or D2O composition should be viewed with caution until it is verified
that the compound remains in the same phase over the composition range of the
study.
| [
"cond-mat.supr-con"
] | cond-mat.supr-con | Superconductivity | 7,066Superconductivity
|
|
1207.6347 | We review recent stability and separation results in volume comparison
problems and use them to prove several hyper- plane inequalities for
intersection and projection bodies.
| [
"math.MG"
] | math.MG | Metric Geometry | 4,601Metric Geometry
|
|
cond-mat/0510150 | The question if a Mott insulator and a band insulator are fundamentally
different has been the matter of intensive research recently. Here we consider
a simple model which allows by tuning one parameter to go continously from a
Mott insulator to band insulator. The model consists of two Hubbard systems
connected by single particle hopping. The Hubbard Hamiltonian is solved by the
Dynamical Mean-Field theory using Quantum Monte Carlo to solve the resulting
quantum impurity problem. The quasiparticle spectral function is calculated.
Here we focus on the optical conductivity and in particular on the Drude weight
which can be experimentally measured. From our calculation we conclude that
there is a continous crossover from the band insulator to the Mott insulator
phase at finite temperature.
| [
"cond-mat.str-el"
] | cond-mat.str-el | Strongly Correlated Electrons | 6,979Strongly Correlated Electrons
|
|
2203.12510 | For $\tau\in S_3$, let $S_n(\tau)$ denote the set of permutations in $S_n$
which avoid the pattern $\tau$, and let $E_n^\tau$ denote the expectation with
respect to the uniformly random probability measure on $S_n(\tau)$. Let
$\mathcal{I}_n(\sigma)$ denote the number of inversions in $\sigma\in S_n$. We
study $E_n^\tau\mathcal{I}_n$ for $\tau\in\{231,132,213,312\}\subset S_3$. We
prove that $$
E_n^{231}\mathcal{I}_n=E_n^{312}\mathcal{I}_n=\frac12\frac{n!(n+1)!4^n}{(2n)!}-\frac12(3n+1),
$$ and that $$
E_n^{132}\mathcal{I}_n=E_n^{213}\mathcal{I}_n=\frac12(n-1)n-E_n^{231}\mathcal{I}_n.
$$ From the first equation it follows that $$
E_n^{231}\mathcal{I}_n=E_n^{312}\mathcal{I}_n\sim\frac{\sqrt\pi}2n^\frac32. $$
We also show that the variance $\text{Var}_{P_n^{\tau}}(\mathcal{I}_n)$ of
$\mathcal{I}_n$ under $P_n^\tau$ satisfies $$
\text{Var}_{P_n^{\tau}}(\mathcal{I}_n)\sim (\frac56-\frac\pi4)n^3\approx
0.048n^3,\ \text{for}\ \tau\in\{231,132,213,312\}. $$
| [
"math.PR",
"math.CO"
] | math.PR | math.CO | Probability;Combinatorics | 5,726Probability;Combinatorics
|
1703.04950 | The title equation is completely solved in integers $(n,x,y,a,b)$, where
$n\geq 3$, $\gcd(x,y)=1$ and $a,b\geq 0$. The most difficult stage of the
resolution is the explicit resolution of a quintic Thue-Mahler equation. Since
it is for the first time -to the best of our knowledge- that such an equation
is solved in the literature, we make a detailed presentation of the resolution;
this gives our paper also an expository character.
| [
"math.NT"
] | math.NT | Number Theory | 4,945Number Theory
|
|
2105.12780 | The cross section for W or Z boson production in association with two photons
is measured in proton-proton collisions at a centre-of-mass energy of 13 TeV.
The data set corresponds to an integrated luminosity of 137 fb$^{-1}$ collected
by the CMS experiment at the LHC. The W $\to$ $\ell\nu$ and Z $\to$ $\ell\ell$
decay modes (where $\ell =$ e, $\mu$) are used to extract the W$\gamma\gamma$
and Z$\gamma\gamma$ cross sections in a phase space defined by electron (muon)
with transverse momentum larger than 30 GeV and photon transverse momentum
larger than 20 GeV. All leptons and photons are required to have absolute
pseudorapidity smaller than 2.5. The measured cross sections in this phase
space are $\sigma$(W$\gamma\gamma$) = 13.6 $^{+1.9}_{-1.9}$ (stat)
${}^{+4.0}_{-4.0}$ (syst) $\pm$ 0.08 (PDF + scale) fb and
$\sigma$(Z$\gamma\gamma$) = 5.41 $^{+0.58}_{-0.55}$ (stat) ${}^{+0.64}_{-0.70}$
(syst) $\pm$ 0.06 (PDF + scale) fb. Limits on anomalous quartic gauge couplings
are set in the framework of an effective field theory with dimension-8
operators.
| [
"hep-ex"
] | hep-ex | High Energy Physics - Experiment | 3,059High Energy Physics - Experiment
|
|
1406.1041 | We revisit the problem of computing the edit distance of a regular language
given via an NFA. This problem relates to the inherent maximal error-detecting
capability of the language in question. We present an efficient algorithm for
solving this problem which executes in time $O(r^2n^2d)$, where $r$ is the
cardinality of the alphabet involved, $n$ is the number of transitions in the
given NFA, and $d$ is the computed edit distance. We have implemented the
algorithm and present here performance tests. The correctness of the algorithm
is based on the result (also presented here) that the particular
error-detection property related to our problem can be defined via an
input-altering transducer.
| [
"cs.FL"
] | cs.FL | Formal Languages and Automata Theory | 2,525Formal Languages and Automata Theory
|
|
2311.04729 | In this study, we present our latest findings regarding azimuthal
distributions in vector boson + jets and multi-jet production at the Large
Hadron Collider (LHC). These findings result from matching next-to-leading
order (NLO) perturbative matrix elements with transverse momentum dependent
(TMD) parton branching. We conduct a comprehensive comparative analysis of
azimuthal correlations between Z boson-jet and jet-jet systems in the
back-to-back region. These distinct azimuthal correlation patterns can help
identify potential factorization-breaking effects in this region. Such effects
depend on the different color and spin structures of the final states and their
interactions with the initial states.
| [
"hep-ph"
] | hep-ph | High Energy Physics - Phenomenology | 3,129High Energy Physics - Phenomenology
|
|
1108.1706 | Tree-level gauge mediation (TGM) is a scenario of SUSY breaking in which the
tree-level exchange of heavy (possibly GUT) vector fields generates
flavor-universal sfermion masses. In this work we extend this framework to the
case of E_6 that is the natural extension of the minimal case studied so far.
Despite the number of possible E_6 subgroups containing G_SM is large (we list
all rank 6 subgroups), there are only three different cases corresponding to
the number of vector messengers. As a robust prediction we find that sfermion
masses are SU(5) invariant at the GUT scale, even if the gauge group does not
contain SU(5). If SUSY breaking is mediated purely by the U(1) generator that
commutes with SO(10) we obtain universal sfermion masses and thus can derive
the CMSSM boundary conditions in a novel scenario.
| [
"hep-ph"
] | hep-ph | High Energy Physics - Phenomenology | 3,129High Energy Physics - Phenomenology
|
|
2303.10447 | Our goal is to find a representative of each orbit of the coadjoint action of
the generalized Galile group on the dual of its Lie algebra. Our line of
argument follows that of Cushman and van der Kallen, but differs in the
details.
| [
"math.SG"
] | math.SG | Symplectic Geometry | 7,123Symplectic Geometry
|
|
1404.4111 | A method is presented which makes considerably more transparent possible
patterns behind low-energy scattering data. In particular, structures
associated with resonances, such as locations, widths and heights, become
visible with a naked eye. The method is illustrated with a study of the
$P$-wave $K\pi$ amplitude.
| [
"hep-ph"
] | hep-ph | High Energy Physics - Phenomenology | 3,129High Energy Physics - Phenomenology
|
|
2110.13159 | We study the impact of selection biases on jet structure and substructure
observables and separate these effects from effects caused by jet quenching. We
use the angular separation $\Delta R$ of the hardest splitting in a jet as the
primary example observable. We first conduct a simplified Monte Carlo study in
which it is possible to identify the same jet after quenching in a heavy ion
collision and as it would have been if it had formed in vacuum. We select a
sample of jets by placing a cut on their quenched $p_T$ and, as is possible
only in a Monte Carlo study, compare to the same jets unquenched, and see that
the $\Delta R$ distribution seems to be unmodified. However, if we select a
sample of jets formed in vacuum by placing a cut on their unquenched $p_T$ and
compare to those same jets after quenching, we see a significant enhancement in
the number of jets with large $\Delta R$, primarily due to the soft particles
in the jet that originate from the wake in the droplet of quark-gluon plasma
excited by the parton shower. We confirm that the jets contributing to this
enhancement are those jets which lost the most energy, which were not included
in the sample selected after quenching; jets selected after quenching are those
which lose a small fraction of their energy. Next, we employ a method that is
available to experimentalists: in a sample of jets with a recoiling $Z$ boson,
we show that selecting jets based on the jet $p_T$ after quenching yields a
$\Delta R$ distribution that appears unmodified while selecting a sample of
jets produced in association with a $Z$ boson whose (unmodified) $p_T$ is above
some cut yields a significant enhancement in the number of jets with large
$\Delta R$. We again confirm that this is due to particles from the wake, and
that the jets contributing to this enhancement are those which have lost a
significant fraction of their energy.
| [
"hep-ph",
"nucl-th"
] | hep-ph | nucl-th | High Energy Physics - Phenomenology;Nuclear Theory | 3,240High Energy Physics - Phenomenology;Nuclear Theory
|
1904.01090 | We experimentally realize a photonic analogue of the anomalous quantum Hall
insulator using a two-dimensional (2D) array of coupled ring resonators.
Similar to the Haldane model, our 2D array is translation invariant, has zero
net gauge flux threading the lattice, and exploits next-nearest neighbor
couplings to achieve a topologically non-trivial bandgap. Using direct imaging
and on-chip transmission measurements, we show that the bandgap hosts
topologically robust edge states. We demonstrate a topological phase transition
to a conventional insulator by frequency detuning the ring resonators and
thereby breaking the inversion symmetry of the lattice. Furthermore, the
clockwise or the counter-clockwise circulation of photons in the ring
resonators constitutes a pseudospin degree of freedom. We show that the two
pseudospins acquire opposite hopping phases and their respective edge states
propagate in opposite directions. These results are promising for the
development of robust reconfigurable integrated nanophotonic devices for
applications in classical and quantum information processing.
| [
"physics.optics"
] | physics.optics | Optics | 5,146Optics
|
|
0802.4379 | We review some theoretical and phenomenological aspects of massive gravities
in 4 dimensions. We start from the Fierz--Pauli theory with Lorentz-invariant
mass terms and then proceed to Lorentz-violating masses. Unlike the former
theory, some models with Lorentz-violation have no pathologies in the spectrum
in flat and nearly flat backgrounds and lead to interesting phenomenology.
| [
"hep-th"
] | hep-th | High Energy Physics - Theory | 3,266High Energy Physics - Theory
|
|
quant-ph/0602140 | We attempt to clarify certain puzzles concerning state collapse and
decoherence. In open quantum systems decoherence is shown to be a necessary
consequence of the transfer of information to the outside; we prove an upper
bound for the amount of coherence which can survive such a transfer. We claim
that in large closed systems decoherence has never been observed, but we will
show that it is usually harmless to assume its occurrence. An independent
postulate of state collapse over and above Schroedinger's equation and the
probability interpretation of quantum states, is shown to be redundant.
| [
"quant-ph"
] | quant-ph | Quantum Physics | 5,985Quantum Physics
|
|
1212.6538 | This paper details the investigation of the influence of different disorders
in two-dimensional topological insulator systems. Unlike the phase transitions
to topological Anderson insulator induced by normal Anderson disorder, a
different physical picture arises when bond disorder is considered. Using Born
approximation theory, an explanation is given as to why bond disorder plays a
different role in phase transition than does Anderson disorder. By comparing
phase diagrams, conductance, conductance fluctuations, and the localization
length for systems with different types of disorder, a consistent conclusion is
obtained. The results indicate that a topological Anderson insulator is
dependent on the type of disorder. These results are important for the doping
processes used in preparation of topological insulators.
| [
"cond-mat.dis-nn",
"cond-mat.mtrl-sci"
] | cond-mat.dis-nn | cond-mat.mtrl-sci | Disordered Systems and Neural Networks;Materials Science | 2,143Disordered Systems and Neural Networks;Materials Science
|
gr-qc/0511003 | The generalized Chaplygin gas (GCG) is a candidate for the unification of
dark energy and dark matter, and is parametrized by an exotic equation of state
given by $p_{ch}=-A/\rho_{ch}^{\alpha}$, where $A$ is a positive constant and
$0<\alpha \leq 1$. In this paper, exact solutions of spherically symmetric
traversable wormholes supported by the GCG are found, possibly arising from a
density fluctuation in the GCG cosmological background. To be a solution of a
wormhole, the GCG equation of state imposes the following generic restriction
$A<(8\pi r_0^2)^{-(1+\alpha)}$, where $r_0$ is the wormhole throat radius,
consequently violating the null energy condition. The spatial distribution of
the exotic GCG is restricted to the throat neighborhood, and the physical
properties and characteristics of these Chaplygin wormholes are further
analyzed. Four specific solutions are explored in some detail, namely, that of
a constant redshift function, a specific choice for the form function, a
constant energy density, and finally, isotropic pressure Chaplygin wormhole
geometries.
| [
"gr-qc",
"astro-ph",
"hep-th"
] | gr-qc | astro-ph | General Relativity and Quantum Cosmology;Astrophysics;High Energy Physics - Theory | 2,688General Relativity and Quantum Cosmology;Astrophysics;High Energy Physics - Theory
|
2208.06329 | Probabilistic programming makes it easy to represent a probabilistic model as
a program. Building an individual model, however, is only one step of
probabilistic modeling. The broader challenge of probabilistic modeling is in
understanding and navigating spaces of alternative models. There is currently
no good way to represent these spaces of alternative models, despite their
central role. We present an extension of probabilistic programming that lets
each program represent a network of interrelated probabilistic models. We give
a formal semantics for these multi-model probabilistic programs, a collection
of efficient algorithms for network-of-model operations, and an example
implementation built on top of the popular probabilistic programming language
Stan. This network-of-models representation opens many doors, including search
and automation in model-space, tracking and communication of model development,
and explicit modeler degrees of freedom to mitigate issues like p-hacking. We
demonstrate automatic model search and model development tracking using our
Stan implementation, and we propose many more possible applications.
| [
"cs.PL",
"cs.LG",
"stat.ME"
] | cs.PL | cs.LG | Programming Languages;Machine Learning;Methodology | 7,267longtail
|
1002.1125 | In this chapter, we consider a class of discrete dynamical systems defined on
the homogeneous space associated with a regular tiling of $\R^N$, whose most
familiar example is provided by the $N-$dimensional torus $\T ^N$. It is proved
that any dynamical system in this class is chaotic in the sense of Devaney, and
that it admits at least one positive Lyapunov exponent. Next, a
chaos-synchronization mechanism is introduced and used for masking information
in a communication setup.
| [
"math.AP"
] | math.AP | Analysis of PDEs | 205Analysis of PDEs
|
|
1610.01438 | The conservative sequence of a set $A$ under a transformation $T$ is the set
of all $n \in \mathbb{Z}$ such that $T^n A \cap A \not = \varnothing$. By
studying these sequences, we prove that given any countable collection of
nonsingular transformations with no finite invariant measure $\{T_i\}$, there
exists a rank-one transformation $S$ such that $T_i \times S$ is not ergodic
for all $i$. Moreover, $S$ can be chosen to be rigid or have infinite ergodic
index. We establish similar results for $\mathbb{Z}^d$ actions and flows. Then,
we find sufficient conditions on rank-one transformations $T$ that guarantee
the existence of a rank-one transformation $S$ such that $T \times S$ is
ergodic, or, alternatively, conditions that guarantee that $T \times S$ is
conservative but not ergodic. In particular, the infinite Chac\'on
transformation satisfies both conditions. Finally, for a given ergodic
transformation $T$, we study the Baire categories of the sets $E(T)$,
$\bar{E}C(T)$ and $\bar{C}(T)$ of transformations $S$ such that $T \times S$ is
ergodic, ergodic but not conservative, and conservative, respectively.
| [
"math.DS"
] | math.DS | Dynamical Systems | 2,265Dynamical Systems
|
|
2306.02098 | Safety clothing and helmets play a crucial role in ensuring worker safety at
construction sites. Recently, deep learning methods have garnered significant
attention in the field of computer vision for their potential to enhance safety
and efficiency in various industries. However, limited availability of
high-quality datasets has hindered the development of deep learning methods for
safety clothing and helmet detection. In this work, we present a large,
comprehensive, and realistic high-quality dataset for safety clothing and
helmet detection, which was collected from a real-world chemical plant and
annotated by professional security inspectors. Our dataset has been compared
with several existing open-source datasets, and its effectiveness has been
verified applying some classic object detection methods. The results
demonstrate that our dataset is more complete and performs better in real-world
settings. Furthermore, we have released our deployment code to the public to
encourage the adoption of our dataset and improve worker safety. We hope that
our efforts will promote the convergence of academic research and industry,
ultimately contribute to the betterment of society.
| [
"cs.CV"
] | cs.CV | Computer Vision and Pattern Recognition | 1,498Computer Vision and Pattern Recognition
|
|
2006.16862 | Josephson tunnel junctions are the centerpiece of almost any superconducting
electronic circuit, including qubits. Typically, the junctions for qubits are
fabricated using shadow evaporation techniques to reduce dielectric loss
contributions from the superconducting film interfaces. In recent years,
however, sub-micron scale overlap junctions have started to attract attention.
Compared to shadow mask techniques, neither an angle dependent deposition nor
free-standing bridges or overlaps are needed, which are significant limitations
for wafer-scale processing. This comes at the cost of breaking the vacuum
during fabrication, but simplifies integration in multi-layered circuits,
implementation of vastly different junction sizes, and enables fabrication on a
larger scale in an industrially-standardized process. In this work, we
demonstrate the feasibility of a subtractive process for fabrication of overlap
junctions. In an array of test contacts, we find low aging of the average
normal state resistance of only 1.6\% over 6 months. We evaluate the coherence
properties of the junctions by employing them in superconducting transmon
qubits. In time domain experiments, we find that both, the qubit life- and
coherence time of our best device, are on average greater than
$20\,\si{\micro\second}$. Finally, we discuss potential improvements to our
technique. This work paves the way towards a more standardized process flow
with advanced materials and growth processes, and constitutes an important step
for large scale fabrication of superconducting quantum circuits.
| [
"quant-ph"
] | quant-ph | Quantum Physics | 5,985Quantum Physics
|
|
2301.00326 | In this paper, we investigate the possibility of the
backward-differential-flow-like algorithm which starts from the minimum of
convexification version of the polynomial. We apply the heat evolution
convexification approach through Gaussian filtering, which is actually an
accumulation version of Steklov's regularization. We generalize the fingerprint
theory which was proposed in the theory of computer vision by A.L. Yuille and
T. Poggio in 1980s, in particular their fingerprint trajectory equation, to
characterize the evolution of minimizers across the scale. On the other hand,
we propose the "seesaw" polynomials $p(x|s)$ and we find a seesaw differential
equation $\frac{\partial p(x|s)}{\,ds}=-\frac{1}{p''(x)}$ to characterize the
evolution of global minimizer $x^*(s)$ of $p(x|s)$ while varying $s$.
Essentially, both the fingerprints $\mathcal{FP}_2$ and $\mathcal{FP}_3$ of
$p(x)$, consisting of the zeros of $\frac{\partial^2 p(x,t)}{\partial x^2}$ and
$\frac{\partial^3 p(x,t)}{\partial x^3}$, respectively, are independent of
seesaw coefficient $s$, upon which we define the Confinement Zone and Escape
Zone. Meanwhile, varying $s$ will monotonically condition the location of
global minimizer of $p(x|s)$, and all these location form the Attainable Zone.
Based on these concepts, we prove that the global minimizer $x^*$ of $p(x)$ can
be inversely evolved from the global minimizer of its convexification
polynomial $p(x,t_0)$ if and only if $x^*$ is included in the Escape Zone. In
particular, we give detailed analysis for quartic and six degree polynomials.
| [
"math.OC",
"cs.CV"
] | math.OC | cs.CV | Optimization and Control;Computer Vision and Pattern Recognition | 5,267Optimization and Control;Computer Vision and Pattern Recognition
|
1910.04858 | Uncertainty estimation is an essential step in the evaluation of the
robustness for deep learning models in computer vision, especially when applied
in risk-sensitive areas. However, most state-of-the-art deep learning models
either fail to obtain uncertainty estimation or need significant modification
(e.g., formulating a proper Bayesian treatment) to obtain it. Most previous
methods are not able to take an arbitrary model off the shelf and generate
uncertainty estimation without retraining or redesigning it. To address this
gap, we perform a systematic exploration into training-free uncertainty
estimation for dense regression, an unrecognized yet important problem, and
provide a theoretical construction justifying such estimations. We propose
three simple and scalable methods to analyze the variance of outputs from a
trained network under tolerable perturbations: infer-transformation,
infer-noise, and infer-dropout. They operate solely during the inference,
without the need to re-train, re-design, or fine-tune the models, as typically
required by state-of-the-art uncertainty estimation methods. Surprisingly, even
without involving such perturbations in training, our methods produce
comparable or even better uncertainty estimation when compared to
training-required state-of-the-art methods.
| [
"cs.CV",
"cs.LG"
] | cs.CV | cs.LG | Computer Vision and Pattern Recognition;Machine Learning | 1,593Computer Vision and Pattern Recognition;Machine Learning
|
1412.2360 | A structure of a left-symmetric algebra on the set of all derivations of a
free algebra is introduced such that its commutator algebra becomes the usual
Lie algebra of derivations. Left and right nilpotent elements of left-symmetric
algebras of derivations are studied. Simple left-symmetric algebras of
derivations and Novikov algebras of derivations are described. It is also
proved that the positive part of the left-symmetric algebra of derivations of a
free nonassociative symmetric $m$-ary algebra in one free variable is generated
by one derivation and some right nilpotent derivations are described.
| [
"math.RA"
] | math.RA | Rings and Algebras | 6,272Rings and Algebras
|
|
0804.3508 | Our aim is to identify and trace the X-ray Bright Points (XBPs) over the disk
and use them as tracers to determine the coronal rotation. This investigation
will help to clarify and understand several issues: whether (i) the corona
rotates differentially; (ii) the rotation depends on the sizes of the XBPs; and
(iii) dependence on phases of the solar magnetic cycle. We analysed the daily
full-disk soft X-ray images observed with (i) X-Ray Telescope (XRT) on-board
the Hinode mission during January, March and April, 2007 and (ii) Soft X-ray
Telescope (SXT) on-board the Yohkoh from 1992 to 2001 using SSW in IDL. We have
used the tracer method to trace the passage of XBPs over the solar disk with
the help of overlaying grids and derived the sidereal angular rotation velocity
and the coordinates (latitude and longitude) of the XBPs. We have determined
the position of a large number of XBPs both in Hinode/XRT and Yohkoh/SXT images
and followed them over the solar disk as a function of time. We derived the
coronal sidereal angular rotation velocity and compared it with heliocentric
latitude and as a function of solar activity cycle. In addition, we measured
the sizes of all the XBPs and related them with the coronal rotation. The
important results derived from these investigations are: (i) the solar corona
rotates differentially like the photosphere and chromosphere; (ii) the sidereal
angular rotation velocity is independent of the sizes of the XBPs; (iii) the
sidereal angular rotation velocity does not depend on phases of the solar
magnetic cycle; and (iv) the differential rotation of the corona is present
throughout the solar magnetic cycle.
| [
"astro-ph"
] | astro-ph | Astrophysics | 463Astrophysics
|
|
1501.00063 | The irreducible modules of the 2-cycle permutation orbifold models of lattice
vertex operator algebras of rank 1 are classified, the quantum dimensions of
irreducible modules and the fusion rules are determined.
| [
"math.QA"
] | math.QA | Quantum Algebra | 5,873Quantum Algebra
|
|
2304.00341 | We propose a method that trains a neural radiance field (NeRF) to encode not
only the appearance of the scene but also semantic correlations between scene
points, regions, or entities -- aiming to capture their mutual co-variation
patterns. In contrast to the traditional first-order photometric reconstruction
objective, our method explicitly regularizes the learning dynamics to align the
Jacobians of highly-correlated entities, which proves to maximize the mutual
information between them under random scene perturbations. By paying attention
to this second-order information, we can shape a NeRF to express semantically
meaningful synergies when the network weights are changed by a delta along the
gradient of a single entity, region, or even a point. To demonstrate the merit
of this mutual information modeling, we leverage the coordinated behavior of
scene entities that emerges from our shaping to perform label propagation for
semantic and instance segmentation. Our experiments show that a JacobiNeRF is
more efficient in propagating annotations among 2D pixels and 3D points
compared to NeRFs without mutual information shaping, especially in extremely
sparse label regimes -- thus reducing annotation burden. The same machinery can
further be used for entity selection or scene modifications.
| [
"cs.CV"
] | cs.CV | Computer Vision and Pattern Recognition | 1,498Computer Vision and Pattern Recognition
|
|
1206.5446 | In this paper we consider the entire weak solutions $u$ of the equations for
stationary flows of shear thickening fluids in the plane and prove Liouville
theorems under the conditions on the finiteness of energy and under the
integrability condition of the solutions.
| [
"math.AP"
] | math.AP | Analysis of PDEs | 205Analysis of PDEs
|
|
1008.0374 | The influence of delay-time between two sequential femtosecond pulses on the
properties of nanoparticles obtained via laser ablation of gold in ethanol has
been studied. The morphological and optical properties of the nanoparticles
attained were characterized using high resolution transmission electron
microscopy and UV_Vis absorption spectroscopy, respectively. Furthermore, the
size distribution of nanoparticles was determined by means of a centrifugal
sedimentation particle size analyzer. It is found that the time delay
variations lead to corresponding changes in size distribution, plasmon
resonance position as well as the rate of nanoparticles generation.
| [
"cond-mat.mes-hall"
] | cond-mat.mes-hall | Mesoscale and Nanoscale Physics | 4,450Mesoscale and Nanoscale Physics
|
|
1704.03930 | Electroweak boson-tagged jet measurements provide a promising experimental
channel to accurately study the physics of jet production and propagation in
dense QCD medium. In this talk, we present theoretical predictions for the
nuclear-induced attenuation of the differential cross section for isolated
photon-tagged and $\rm Z^0$-tagged jet production in heavy ion collisions, and
provide theoretical interpretations to the recent LHC data. We demonstrate
quantitatively the significance of collisional and radiative energy losses, as
revealed in the strong momentum asymmetry $d\sigma/dx_{VJ}$ and nuclear
modification $\rm I_{AA}$ in central lead-lead reactions.
| [
"hep-ph",
"nucl-th"
] | hep-ph | nucl-th | High Energy Physics - Phenomenology;Nuclear Theory | 3,240High Energy Physics - Phenomenology;Nuclear Theory
|
1812.11860 | We construct an explicit example of a stable bundle on the twistor space
$\mathrm{Tw}(M)$ of a hyperk\"ahler manifold $M$ whose restrictions to all the
fibres of the natural twistor projection $\pi : \mathrm{Tw}(M) \to
\mathbb{CP}^1$ are nonstable. We also describe the relationship between bundles
on $\mathrm{Tw}(M)$ that do not have subsheaves of strictly lower rank and
bundles that stably restrict to the fibres of $\pi$, and announce a result
whose proof will appear in a forthcoming paper.
| [
"math.DG",
"math.AG"
] | math.DG | math.AG | Differential Geometry;Algebraic Geometry | 2,011Differential Geometry;Algebraic Geometry
|
1409.7571 | I give a brief introduction to the AdS/CFT correspondence targeted at
heavy-ion physicists. I also review some insights to our understanding of the
early stages of heavy-ion collisions coming from selected studies made using
methods of the AdS/CFT correspondence.
| [
"hep-ph",
"hep-th",
"nucl-th"
] | hep-ph | hep-th | High Energy Physics - Phenomenology;High Energy Physics - Theory;Nuclear Theory | 3,227High Energy Physics - Phenomenology;High Energy Physics - Theory;Nuclear Theory
|
0901.1635 | Considering epicyclic oscillations of pressure-supported perfect fluid tori
orbiting Kerr black holes we examine non-geodesic (pressure) effects on the
epicyclic modes properties. Using a perturbation method we derive fully general
relativistic formulas for eigenfunctions and eigenfrequencies of the radial and
vertical epicyclic modes of a slightly non-slender, constant specific angular
momentum torus up to second-order accuracy with respect to the torus thickness.
The behaviour of the axisymmetric and lowest-order ($m=\pm 1$) non-axisymmetric
epicyclic modes is investigated. For an arbitrary black hole spin we find that,
in comparison with the (axisymmetric) epicyclic frequencies of free test
particles, non-slender tori receive negative pressure corrections and exhibit
thus lower frequencies. Our findings are in qualitative agreement with the
results of a recent pseudo-Newtonian study of analogous problem defined within
the Paczy{\'n}ski-Wiita potential. Implications of our results on the
high-frequency QPO models dealing with epicyclic oscillations are addressed.
| [
"astro-ph.SR"
] | astro-ph.SR | Solar and Stellar Astrophysics | 6,668Solar and Stellar Astrophysics
|
|
1108.0431 | We classify two classes of B_2-graded Lie algebras which have a second
compatible grading by an abelian group A: (a) graded-simple Lie algebras for A
torsion-free and (b) division-A-graded Lie algebras. Our results describe the
centreless cores of a class of affine reflection Lie algebras, hence apply in
particular to the centreless cores of extended affine Lie algebras, the
so-called Lie tori, for which we recover results of Allison-Gao and Faulkner.
Our classification (b) extends a recent result of Benkart-Yoshii.
Both classifications are consequences of a new description of Jordan algebras
covered by a triangle, which correspond to these Lie algebras via the
Tits-Kantor-Koecher construction. The Jordan algebra classifications follow
from our results on graded-triangulated Jordan triple systems. They generalize
work of McCrimmon and the first author as well as the
Osborn-McCrimmon-Capacity-2-Theorem in the ungraded case.
| [
"math.RA",
"math.RT"
] | math.RA | math.RT | Rings and Algebras;Representation Theory | 6,307Rings and Algebras;Representation Theory
|
hep-th/9303161 | We define multi-colour generalizations of braid-monoid algebras and present
explicit matrix representations which are related to two-dimensional exactly
solvable lattice models of statistical mechanics. In particular, we show that
the two-colour braid-monoid algebra describes the Yang-Baxter algebra of the
critical dilute A-D-E models which were recently introduced by Warnaar,
Nienhuis, and Seaton as well as by Roche. These and other solvable models
related to dense and dilute loop models are discussed in detail and it is shown
that the solvability is a direct consequence of the algebraic structure. It is
conjectured that the Yang-Baxterization of general multi-colour braid-monoid
algebras will lead to the construction of further solvable lattice models.
| [
"hep-th",
"math.QA"
] | hep-th | math.QA | High Energy Physics - Theory;Quantum Algebra | 3,379High Energy Physics - Theory;Quantum Algebra
|
1211.2425 | Minimax single facility location problems in multidimensional space with
Chebyshev distance are examined within the framework of idempotent algebra. The
aim of the study is twofold: first, to give a new algebraic solution to the
location problems, and second, to extend the area of application of idempotent
algebra. A new algebraic approach based on investigation of extremal properties
of eigenvalues for irreducible matrices is developed to solve multidimensional
problems that involve minimization of functionals defined on idempotent vector
semimodules. Furthermore, an unconstrained location problem is considered and
then represented in the idempotent algebra settings. A new algebraic solution
is given that reduces the problem to evaluation of the eigenvalue and
eigenvectors of an appropriate matrix. Finally, the solution is extended to
solve a constrained location problem.
| [
"math.OC"
] | math.OC | Optimization and Control | 5,234Optimization and Control
|
|
cond-mat/9804267 | We have studied quantization and confinement effects in nanostructured
superconductors. Three different types of nanostructured samples were
investigated: individual structures (line, loop, dot), 1-dimensional (1D)
clusters of loops and 2D clusters of antidots, and finally large lattices of
antidots. Hereby, a crossover from individual elementary "plaquettes", via
clusters, to huge arrays of these elements, is realized. The main idea of our
study was to vary the boundary conditions for confinement of the
superconducting condensate by taking samples of different topology and, through
that, modifying the lowest Landau level E_LLL(H). Since the critical
temperature versus applied magnetic field T_c(H) is, in fact, E_LLL(H) measured
in temperature units, it is varied as well when the sample topology is changed
through nanostructuring. We demonstrate that in all studied nanostructured
superconductors the shape of the T_c(H) phase boundary is determined by the
confinement topology in a unique way.
| [
"cond-mat.supr-con",
"cond-mat.mes-hall"
] | cond-mat.supr-con | cond-mat.mes-hall | Superconductivity;Mesoscale and Nanoscale Physics | 7,083Superconductivity;Mesoscale and Nanoscale Physics
|
2307.11755 | The STEM field is unrepresentative of the population it serves. Due to a lack
of cultural relevance in STEM courses, there is a dissociation between the
lived experience of students from underrepresented racial groups (URG) and STEM
course material. The SPORT-C intervention is a framework that combines sports,
systems thinking learning, and a case-based pedagogy into an activity that can
be used in any STEM course. A pilot study was conducted to determine the
viability of the SPORT-C intervention in a classroom setting and determine if
it was worth further investigating and if any impact differed by racial
identity. The findings from this study implicate that the SPORT-C intervention
has an impact on the motivation levels of students to participate in STEM
courses.
| [
"physics.ed-ph"
] | physics.ed-ph | Physics Education | 5,448Physics Education
|
|
1101.2989 | The spectral data of a vibrating string are encoded in its so-called
characteristic function. We consider the problem of recovering the distribution
of mass along the string from its characteristic function. It is well-known
that Stieltjes' continued fraction provides a solution of this inverse problem
in the particular case where the distribution of mass is purely discrete. We
show how to adapt Stieltjes' method to solve the inverse problem for a related
class of strings. An application to the excursion theory of diffusion processes
is presented.
| [
"math.SP",
"math.PR"
] | math.SP | math.PR | Spectral Theory;Probability | 6,797Spectral Theory;Probability
|
2010.06898 | Rigid meromorphic cocycles were introduced by Darmon and Vonk as a
conjectural $p$-adic extension of the theory of singular moduli to real
quadratic base fields. They are certain cohomology classes of
$\mathrm{SL}_2(\mathbb{Z}[1/p])$ which can be evaluated at real quadratic
irrationalities and the values thus obtained are conjectured to lie in
algebraic extensions of the base field. In this article we present a similar
construction of cohomology casses in which $\mathrm{SL}_2(\mathbb{Z}[1/p])$ is
replaced by an order in an indefinite quaternion algebra over a totally real
number field $F$. These quaternionic cohomology classes can be evaluated at
elements in almost totally complex extensions $K$ of $F$, and we conjecture
that the corresponding values lie in algebraic extensions of $K$. We also
report on extensive numerical evidence for this algebraicity conjecture.
| [
"math.NT"
] | math.NT | Number Theory | 4,945Number Theory
|
|
1308.2510 | It is shown that each linear operator on a separable Hilbert space which
generates a finite type I von Neumann algebra has, up to unitary equivalence, a
unique representation as a direct integral of inflations of mutually unitary
inequivalent irreducible matrices. This leads to a simplification of the
so-called prime (or central) decomposition and the multiplicity theory for such
operators. The concept of so-called p-isomorphisms between special classes of
such operators is discussed. All results are formulated in more general
settings; that is, for tuples of closed densely defined operators affiliated
with finite type I von Neumann algebras.
| [
"math.FA"
] | math.FA | Functional Analysis | 2,549Functional Analysis
|
|
cond-mat/0103093 | The Kondo effect in coupled quantum dots is investigated from the viewpoint
of transmission spectroscopy using the slave-boson formalism of the Anderson
model. The antiferromagnetic spin-spin coupling $J$ between the dots is taken
into account. Conductance $G$ through the dots connected in a series is
characterized by the competition between the dot-dot tunneling coupling $V_{C}$
and the level broadening $\Delta$ in the dots (dot-lead coupling). When
$V_{C}/\Delta < 1$, the Kondo resonance is formed between each dot and lead,
which is replaced by a spin-singlet state in the dots at low gate voltages. The
gate voltage dependence of $G$ has a sharp peak of $2 e^2/h$ in height in the
crossover region between the Kondo and spin-singlet states. The sharp peak of
$G$ survives when the energy levels are different between the dots. When $V_{C}
/ \Delta > 1$, the "molecular levels" between the Kondo resonant states appear;
the Kondo resonant peaks are located below and above the Fermi level in the
leads at low gate voltages. The gate voltage dependence of $G$ has a broad
peak, which is robust against $J$. The broad peak splits into two peaks when
the energy levels are different, reflecting the formation of the asymmetric
molecular levels between the Kondo resonant states.
| [
"cond-mat.mes-hall"
] | cond-mat.mes-hall | Mesoscale and Nanoscale Physics | 4,450Mesoscale and Nanoscale Physics
|
|
1707.07472 | We consider a condensate of exciton-polaritons in a diluted magnetic
semiconductor microcavity. Such system may exhibit magnetic self-trapping in
the case of sufficiently strong coupling between polaritons and magnetic ions
embedded in the semiconductor. We investigate the effect of the nonequilibrium
nature of exciton-polaritons on the physics of the resulting self-trapped
magnetic polarons. We find that multiple polarons can exist at the same time,
and derive a critical condition for self-trapping which is different to the one
predicted previously in the equilibrium case. Using the Bogoliubov-de Gennes
approximation, we calculate the excitation spectrum and provide a physical
explanation in terms of the effective magnetic attraction between polaritons,
mediated by the ion subsystem.
| [
"cond-mat.quant-gas"
] | cond-mat.quant-gas | Quantum Gases | 5,914Quantum Gases
|
|
1905.08311 | MacMahon's theorem on plane partitions yields a simple product formula for
tiling number of a hexagon, and Cohn, Larsen and Propp's theorem provides an
explicit enumeration for tilings of a dented semihexagon via semi-strict
Gelfand--Tsetlin patterns. In this paper, we prove a natural hybrid of the two
theorems for hexagons with an arbitrary set of unit triangles removed along a
horizontal axis. In particular, we show that the `shuffling' of removed unit
triangles only changes the tiling number of the region by a simple
multiplicative factor. Our main result generalizes a number of known
enumerations and asymptotic enumerations of tilings. We also reveal connections
of the main result to the study of symmetric functions and $q$-series.
| [
"math.CO"
] | math.CO | Combinatorics | 1,014Combinatorics
|
|
2011.02380 | Spontaneous condensation of excitons is a long sought phenomenon analogous to
the condensation of Cooper pairs in a superconductor. It is expected to occur
in a semiconductor at thermodynamic equilibrium if the binding energy of the
excitons---electron (e) and hole (h) pairs interacting by Coulomb
force---overcomes the band gap, giving rise to a new phase: the 'excitonic
insulator' (EI). Transition metal dichalcogenides are excellent candidates for
the EI realization because of reduced Coulomb screening, and indeed a
structural phase transition was observed in few-layer systems. However,
previous work could not disentangle to which extent the origin of the
transition was in the formation of bound excitons or in the softening of a
phonon. Here we focus on bulk MoS2 and demonstrate theoretically that at high
pressure it is prone to the condensation of genuine excitons of finite
momentum, whereas the phonon dispersion remains regular. Starting from
first-principles many-body perturbation theory, we also predict that the
self-consistent electronic charge density of the EI sustains an out-of-plane
permanent electric dipole moment with an antiferroelectric texture in the layer
plane: At the onset of the EI phase, those optical phonons that share the
exciton momentum provide a unique Raman fingerprint for the EI formation.
Finally, we identify such fingerprint in a Raman feature that was previously
observed experimentally, thus providing direct spectroscopic confirmation of an
ideal excitonic insulator phase in bulk MoS2 above 30 GPa.
| [
"cond-mat.str-el"
] | cond-mat.str-el | Strongly Correlated Electrons | 6,979Strongly Correlated Electrons
|
|
2006.04739 | This review article provides a bird's-eye view of what first-principles based
methods can contribute to next-generation device design and simulation. After a
brief overview of methods and capabilities in the area, we focus on published
work by our group since 2015 and current work on $\textrm{CrI}_3$. We introduce
both single- and dual-gate models in the framework of density functional theory
and the constrained random phase approximation in estimating the Hubbard $U$
for 2D systems vs. their 3D counterparts. A wide range of systems, including
graphene-based heterogeneous systems, transition metal dichalcogenides, and
topological insulators, and a rich array of physical phenomena, including the
macroscopic origin of polarization, field effects on magnetic order, interface
state resonance induced peak in transmission coefficients, spin filtration,
etc., are covered. For $\textrm{CrI}_3$ we present our new results on bilayer
systems such as the interplay between stacking and magnetic order, pressure
dependence, and electric field induced magnetic phase transitions. We find that
a bare bilayer $\textrm{CrI}_3$, graphene$\,|\,$bilayer
$\textrm{CrI}_3\,|\,$graphene, $h$-BN$\,|\,$bilayer $\textrm{CrI}_3\,|\,h$-BN,
and $h$-BN$\,|\,$bilayer $\textrm{CrI}_3\,|\,$graphene all have a different
response at high field, while small field the difference is small except for
graphene$\,|\,$bilayer $\textrm{CrI}_3\,|\,$graphene. We conclude with
discussion of some ongoing work and work planned in the near future, with the
inclusion of further method development and applications.
| [
"cond-mat.mes-hall"
] | cond-mat.mes-hall | Mesoscale and Nanoscale Physics | 4,450Mesoscale and Nanoscale Physics
|
|
1804.03689 | The multitude of recent multi-point spacecraft observations of solar
energetic particle (SEP) events have made it possible to study the longitudinal
distribution of SEPs in great detail. SEPs, even those accelerated during
impulsive events, show a much wider than expected longitudinal extent, bringing
into question the processes responsible for their transport perpendicular to
the local magnetic field. In this paper we examine some aspects of
perpendicular transport by including perpendicular diffusion into a numerical
SEP transport model that simulates the propagation of impulsively accelerated
SEP electrons in the ecliptic plane. We find that: (i) The pitch-angle
dependence of the perpendicular diffusion coefficient is an important, and
currently mainly overlooked, transport parameter. (ii) SEP intensities are
generally asymmetric in longitude, being enhanced towards the west of optimal
magnetic connection to the acceleration region. (iii) The maximum SEP intensity
may also be shifted (parameter dependently) away from the longitude of best
magnetic connectivity at 1 AU. We also calculate the maximum intensity, the
time of maximum intensity, the onset time and the maximum anisotropy as a
function of longitude at Earth's orbit and compare the results, in a
qualitative fashion, to recent spacecraft observations.
| [
"astro-ph.SR",
"physics.space-ph"
] | astro-ph.SR | physics.space-ph | Solar and Stellar Astrophysics;Space Physics | 6,723Solar and Stellar Astrophysics;Space Physics
|
1312.7666 | In this paper, a new identity for fractional integrals is established. Then
by making use of the established identity, some new Ostrowski type inequalities
for harmonically s-convex functions via Riemann--Liouville fractional integral
are established.
| [
"math.CA"
] | math.CA | Classical Analysis and ODEs | 934Classical Analysis and ODEs
|
|
1105.2196 | The quantum spin ice model applied to Tb2Ti2O7 predicts that magnetic fields
applied along the [111] axis will induce a partial magnetization plateau [H. R.
Molavian and M. J. P. Gingras, J. Phys.: Condens. Matter 21, 172201 (2009)]. We
test this hypothesis using ac magnetic susceptibility and muon-spin relaxation
measurements, finding features at 15 and 65 mT agreeing with the predicted
boundaries of the magnetization plateau. This suggests that Tb2Ti2O7 is well
described by a quantum spin ice model with an effective exchange constant of
Jeff = 0.17(1) K.
| [
"cond-mat.str-el"
] | cond-mat.str-el | Strongly Correlated Electrons | 6,979Strongly Correlated Electrons
|
|
0803.3096 | One of the remarkable features of quantum mechanics is the ability to ensure
secrecy. Private states embody this effect, as they are precisely those
multipartite quantum states from which two parties can produce a shared secret
that cannot in any circumstance be correlated to an external system. Naturally,
these play an important role in quantum key distribution (QKD) and quantum
information theory. However, a general distillation method has heretofore been
missing. Inspired by Koashi's complementary control scenario (arXiv:0704.3661v1
[quant-ph]), we give a new definition of private states in terms of one party's
potential knowledge of two complementary measurements made on the other and use
this to construct a general method of private state distillation using quantum
error-correcting codes. The procedure achieves the same key rate as recent,
more information-theoretic approaches while demonstrating the physical
principles underlying privacy of the key. Additionally, the same approach can
be used to establish the hashing inequality for entanglement distillation, as
well as the direct quantum coding theorem.
| [
"quant-ph"
] | quant-ph | Quantum Physics | 5,985Quantum Physics
|
|
1601.06365 | Wound healing is an intricate process that involves many types of cells,
reaction pathways as well as chemical, physical and electrical cues. Since
biochemical reactions and physiological events are pH-dependent we study here
pH as an important major characteristic of the wound healing process in the
presence of endogenous and exogenous electric fields. Our model gives the
spatial pH distribution in a wound. In particular we isolate a number of
dimensionless quantities which sets the length, energy and time scales
governing the wound healing process and which can be experimentally tested.
Most interesting finding is that wound pH depends on actual wound size.
| [
"physics.med-ph",
"q-bio.TO"
] | physics.med-ph | q-bio.TO | Medical Physics;Tissues and Organs | 4,449Medical Physics;Tissues and Organs
|
1703.09208 | In a $d-$dimensional strip with $d\geq 2$, we study the non-stationary Stokes
equation with no-slip boundary condition in the lower and upper plates and
periodic boundary condition in the horizontal directions. In this paper we
establish a new maximal regularity estimate in the real interpolation norm
\begin{equation*}
||f||_{(0,1)}=\inf_{f=f_0+f_1}\left\{\left\langle\sup_{0<z<1}
|f_0|\right\rangle+
\left\langle\int_0^{1} |f_1| \frac{dz}{(1-z)z}\right\rangle\right\}\,,
\end{equation*} where the brackets $\langle\cdot\rangle$ denotes the
horizontal-space and time average. The norms involved in the definition of
$\|\cdot\|_{(0,1)}$ are critical for two reasons: the exponents are borderline
for the Calder\'on-Zygmund theory and the weight $1/z$ just fails to be
Muckenhoupt. Therefore, the estimate is only true under horizontal bandedness
condition, (i. e. a restriction to a packet of wave numbers in Fourier space).
The motivation to express the maximal regularity in such a norm comes from an
application to the Rayleigh-B\'enard problem.
| [
"math.AP"
] | math.AP | Analysis of PDEs | 205Analysis of PDEs
|
|
2012.04308 | In this study, we investigate the spatial distribution of highly varying
plasma composition around one of the largest sunspots of solar cycle 24.
Observations of the photosphere, chromosphere, and corona are brought together
with magnetic field modelling of the sunspot in order to probe the conditions
which regulate the degree of plasma fractionation within loop populations of
differing connectivities. We find that in the coronal magnetic field above the
sunspot umbra, the plasma has photospheric composition. Coronal loops rooted in
the penumbra contain fractionated plasma, with the highest levels observed in
the loops that connect within the active region. Tracing field lines from
regions of fractionated plasma in the corona to locations of Alfvenic
fluctuations detected in the chromosphere shows that they are magnetically
linked. These results indicate a connection between sunspot chromospheric
activity and observable changes in coronal plasma composition.
| [
"astro-ph.SR"
] | astro-ph.SR | Solar and Stellar Astrophysics | 6,668Solar and Stellar Astrophysics
|
|
1803.04103 | With an increased interest in applications that require a clean background
image, such as video surveillance, object tracking, street view imaging and
location-based services on web-based maps, multiple algorithms have been
developed to reconstruct a background image from cluttered scenes.
Traditionally, statistical measures and existing image quality techniques have
been applied for evaluating the quality of the reconstructed background images.
Though these quality assessment methods have been widely used in the past,
their performance in evaluating the perceived quality of the reconstructed
background image has not been verified. In this work, we discuss the
shortcomings in existing metrics and propose a full reference Reconstructed
Background image Quality Index (RBQI) that combines color and structural
information at multiple scales using a probability summation model to predict
the perceived quality in the reconstructed background image given a reference
image. To compare the performance of the proposed quality index with existing
image quality assessment measures, we construct two different datasets
consisting of reconstructed background images and corresponding subjective
scores. The quality assessment measures are evaluated by correlating their
objective scores with human subjective ratings. The correlation results show
that the proposed RBQI outperforms all the existing approaches. Additionally,
the constructed datasets and the corresponding subjective scores provide a
benchmark to evaluate the performance of future metrics that are developed to
evaluate the perceived quality of reconstructed background images.
| [
"cs.CV"
] | cs.CV | Computer Vision and Pattern Recognition | 1,498Computer Vision and Pattern Recognition
|
|
1001.2833 | We consider the $\mathrm{AdS}_3/\mathrm{CFT}_2$ description of
Reissner-Nordstr{\o}m black holes by studying their uplifted counterparts in
five dimensions. Assuming a natural size of the extra dimension, the near
horizon geometries for the extremal limit are exactly $\mathrm{AdS}_3 \times
\mathrm{S}^2$. We compute the scattering amplitude of a scalar field, with a
mode near threshold of frequency and extra dimensional momentum, by a near
extremal uplifted black hole. The absorption cross section agrees with the two
point function of the CFT dual to the scalar field.
| [
"hep-th"
] | hep-th | High Energy Physics - Theory | 3,266High Energy Physics - Theory
|
|
2201.11529 | The radio emission in radio-quiet quasars (RQQs) has been a long mystery and
its physical origin remains unclear. In a previous work we find UV/optical more
variable quasars have stronger X-ray emission, indicating a link between disc
turbulence and X-ray corona heating. In this work, for the first time, we
investigate the relation between UV/optical variability and the radio emission
in RQQs selected from SDSS stripe 82 and FIRST radio survey. We median stack
the FIRST images and detect clear signals from RQQs in the co-added images of
individually radio non-detected sources. Controlling the effects of other
parameters, including redshift, black hole mass, bolometric luminosity and
Eddington ratio, we find more variable RQQs, which are known to be X-ray
relatively brighter, show tentatively weaker radio emission, contrary to the
linear X-ray/radio correlation if the radio emission is from or driven by the
corona. The discovery also suggests that if the radio emission in RQQs is
driven by AGN activity (such as weak jet), the underlying driving process is
independent to the disc turbulence which drives UV/optical variability and
probably also corona heating. Alternatively, the radio emission could be due to
star formation in the host galaxies.
| [
"astro-ph.GA"
] | astro-ph.GA | Astrophysics of Galaxies | 464Astrophysics of Galaxies
|
|
2311.07109 | The neutrinophilic two Higgs doublet model is one of the simplest models to
explain the origin of tiny Dirac neutrino masses. This model introduces a new
Higgs doublet with eV scale VEV to naturally generate the tiny neutrino masses.
Depending on the same Yukawa coupling, the neutrino oscillation patterns can be
probed with the dilepton signature from the decay of charged scalar $H^\pm$.
For example, the normal hierarchy predicts BR$(H^+\to e^+\nu)\ll$ BR$(H^+\to
\mu^+\nu)\approx$ BR$(H^+\to \tau^+\nu)\simeq0.5$ when the lightest neutrino
mass is below 0.01 eV, while the inverted hierarchy predicts BR$(H^+\to
e^+\nu)/2\simeq$ BR$(H^+\to \mu^+\nu)\simeq$ BR$(H^+\to \tau^+\nu)\simeq0.25$.
By precise measurement of BR$(H^+\to \ell^+\nu)$, we are hopefully to probe the
lightest neutrino mass and the atmospheric mixing angle $\theta_{23}$. Through
the detailed simulation of the dilepton signature and corresponding
backgrounds, we find that the 3 TeV CLIC could discover $M_{H^+}\lesssim1220$
GeV for NH and $M_{H^+}\lesssim1280$ GeV for IH. Meanwhile, the future 100 TeV
FCC-hh collider could probe $M_{H^+}\lesssim1810$ GeV for NH and
$M_{H^+}\lesssim2060$ GeV for IH.
| [
"hep-ph",
"hep-ex"
] | hep-ph | hep-ex | High Energy Physics - Phenomenology;High Energy Physics - Experiment | 3,198High Energy Physics - Phenomenology;High Energy Physics - Experiment
|
1803.05022 | The Internet of Things (IoT) realizes a vision where billions of
interconnected devices are deployed just about everywhere, from inside our
bodies to the most remote areas of the globe. As the IoT will soon pervade
every aspect of our lives and will be accessible from anywhere, addressing
critical IoT security threats is now more important than ever. Traditional
approaches where security is applied as an afterthought and as a "patch"
against known attacks are insufficient. Indeed, next-generation IoT challenges
will require a new secure-by-design vision, where threats are addressed
proactively and IoT devices learn to dynamically adapt to different threats. To
this end, machine learning and software-defined networking will be key to
provide both reconfigurability and intelligence to the IoT devices. In this
paper, we first provide a taxonomy and survey the state of the art in IoT
security research, and offer a roadmap of concrete research challenges related
to the application of machine learning and software-defined networking to
address existing and next-generation IoT security threats.
| [
"cs.CR"
] | cs.CR | Cryptography and Security | 1,782Cryptography and Security
|
|
2212.09251 | As language models (LMs) scale, they develop many novel behaviors, good and
bad, exacerbating the need to evaluate how they behave. Prior work creates
evaluations with crowdwork (which is time-consuming and expensive) or existing
data sources (which are not always available). Here, we automatically generate
evaluations with LMs. We explore approaches with varying amounts of human
effort, from instructing LMs to write yes/no questions to making complex
Winogender schemas with multiple stages of LM-based generation and filtering.
Crowdworkers rate the examples as highly relevant and agree with 90-100% of
labels, sometimes more so than corresponding human-written datasets. We
generate 154 datasets and discover new cases of inverse scaling where LMs get
worse with size. Larger LMs repeat back a dialog user's preferred answer
("sycophancy") and express greater desire to pursue concerning goals like
resource acquisition and goal preservation. We also find some of the first
examples of inverse scaling in RL from Human Feedback (RLHF), where more RLHF
makes LMs worse. For example, RLHF makes LMs express stronger political views
(on gun rights and immigration) and a greater desire to avoid shut down.
Overall, LM-written evaluations are high-quality and let us quickly discover
many novel LM behaviors.
| [
"cs.CL",
"cs.AI",
"cs.LG"
] | cs.CL | cs.AI | Computation and Language;Artificial Intelligence;Machine Learning | 1,190Computation and Language;Artificial Intelligence;Machine Learning
|
1507.08780 | We perform full-MHD simulations on various initially helical configurations
and show that they reconfigure into a state where the magnetic field lines span
nested toroidal surfaces. This relaxed configuration is not a Taylor state, as
is often assumed for relaxing plasma, but a state where the Lorentz force is
balanced by the hydrostatic pressure, which is lowest on the central ring of
the nested tori. Furthermore, the structure is characterized by a spatially
slowly varying rotational transform, which leads to the formation of a few
magnetic islands at rational surfaces. We then obtain analytic expressions that
approximate the global structure of the quasi-stable linked and knotted plasma
configurations that emerge, using maps from $S^3$ to $S^2$ of which the Hopf
fibration is a special case. The knotted plasma configurations have a highly
localized magnetic energy density and retain their structure on time scales
much longer than the Alfvenic time scale.
| [
"physics.plasm-ph"
] | physics.plasm-ph | Plasma Physics | 5,556Plasma Physics
|
|
0706.3456 | The crossover between a free magnetic moment phase and a Kondo phase in low
dimensional disordered metals with dilute magnetic impurities is studied.
We perform a finite size scaling analysis of the distribution of the Kondo
temperature as obtained from a numerical renormalization group calculation of
the local magnetic susceptibility and from the solution of the self-consistent
Nagaoka-Suhl equation. We find a sizable fraction of free (unscreened) magnetic
moments when the exchange coupling falls below a disorder-dependent critical
value $J_{\rm c}$. Our numerical results show that between the free moment
phase due to Anderson localization and the Kondo screened phase there is a
phase where free moments occur due to the appearance of random local pseudogaps
at the Fermi energy whose width and power scale with the elastic scattering
rate $1/\tau$.
| [
"cond-mat.str-el",
"cond-mat.mes-hall"
] | cond-mat.str-el | cond-mat.mes-hall | Strongly Correlated Electrons;Mesoscale and Nanoscale Physics | 7,016Strongly Correlated Electrons;Mesoscale and Nanoscale Physics
|
1512.05952 | Strongly coupled quantum dot-cavity systems provide a non-linear
configuration of hybridized light-matter states with promising quantum-optical
applications. Here, we investigate the coherent interaction between strong
laser pulses and quantum dot-cavity polaritons. Resonant excitation of
polaritonic states and their interaction with phonons allow us to observe
coherent Rabi oscillations and Ramsey fringes. Furthermore, we demonstrate
complete coherent control of a quantum dot-photonic crystal cavity based
quantum-bit. By controlling the excitation power and phase in a two-pulse
excitation scheme we achieve access to the full Bloch sphere. Quantum-optical
simulations are in good agreement with our experiments and provide insight into
the decoherence mechanisms.
| [
"cond-mat.mes-hall",
"physics.optics",
"quant-ph"
] | cond-mat.mes-hall | physics.optics | Mesoscale and Nanoscale Physics;Optics;Quantum Physics | 4,520Mesoscale and Nanoscale Physics;Optics;Quantum Physics
|
1706.06843 | We study an optimal control problem for a non-autonomous SEIRS model with
incidence given by a general function of the infective, the susceptible and the
total population, and with vaccination and treatment as control variables. We
prove existence and uniqueness results for our problem and, for the case of
mass-action incidence, we present some simulation results designed to compare
an autonomous and corresponding periodic model, as well as the controlled
versus uncontrolled models.
| [
"math.OC",
"q-bio.PE"
] | math.OC | q-bio.PE | Optimization and Control;Populations and Evolution | 5,329Optimization and Control;Populations and Evolution
|
2211.07485 | The analysis of the central compact object within the supernova remnant HESS
J1731-347 suggests that it has a small radius and, even more interestingly, a
mass of the order or smaller than one solar mass. This raises the question of
which astrophysical process could lead to such a small mass, since the analysis
of various types of SN explosions indicate that is it not possible to produce a
neutron star with a mass smaller than about $1.17 M_\odot$. Here we show that
masses of the order or smaller than one solar mass can be obtained in the case
of strange quark stars and that it is possible to build a coherent model
explaining not only the mass and the radius of that object, but also its slow
cooling suggested in various analyses. We also show that an astrophysical path
exists which leads to the formation of such an object, and we discuss the role
played in that scenario by strangelets assumed to constitute the dark matter.
| [
"astro-ph.HE",
"astro-ph.SR",
"nucl-th"
] | astro-ph.HE | astro-ph.SR | High Energy Astrophysical Phenomena;Solar and Stellar Astrophysics;Nuclear Theory | 3,054High Energy Astrophysical Phenomena;Solar and Stellar Astrophysics;Nuclear Theory
|
1206.1434 | The results of a large area, ~600 deg^2, K-band flux-limited spectroscopic
survey for luminous quasars are presented. The survey utilises the UKIRT
Infrared Deep Sky Survey (UKIDSS) Large Area Survey (LAS) in regions of sky
within the Sloan Digital Sky Survey (SDSS) footprint. The K-band excess (KX) of
all quasars with respect to Galactic stars is exploited in combination with a
photometric redshift/classification scheme to identify quasar candidates for
spectroscopic follow-up observations. The data contained within this
investigation will be able to provide new constraints on the fraction of
luminous quasars reddened by dust with E(B-V)<=0.5 mag. The spectroscopic
sample is defined using the K-band, 14.0<=K<=16.6, and SDSS i-band limits of
i=19.5, 19.7 and 22.0 over sky areas of 287, 150 and 196 deg^2, respectively.
The survey includes >3200 known quasars from the SDSS and more than 250
additional confirmed quasars from the KX-selection. A well-defined sub-sample
of quasars in the redshift interval 1.0<=z<=3.5 includes 1152 objects from the
SDSS and 172 additional KX-selected quasars. The quasar selection is >95 per
cent complete with respect to known SDSS quasars and >95 per cent efficient,
largely independent of redshift and i-band magnitude. The properties of the new
KX-selected quasars confirm the known redshift-dependent effectiveness of the
SDSS quasar selection and provide a sample of luminous quasars experiencing
intermediate levels of extinction by dust. The catalogue represents an
important step towards the assembly of a well-defined sample of luminous
quasars that may be used to investigate the properties of quasars experiencing
intermediate levels of dust extinction within their host galaxies or due
intervening absorption line systems.
| [
"astro-ph.CO"
] | astro-ph.CO | Cosmology and Nongalactic Astrophysics | 1,725Cosmology and Nongalactic Astrophysics
|
|
1906.05161 | We consider the elliptic and parabolic superquadratic diffusive
Hamilton-Jacobi equations with homogeneous Dirichlet conditions. For the
elliptic problem in a half-space, we prove a Liouville-type classification, or
symmetry result, which asserts that any solution has to be one-dimensional.
This turns out to be an efficient tool to study the behavior of boundary
gradient blow-up (GBU) for the parabolic problem in general bounded domains.
Namely, we show that in a neighborhood of the boundary, at leading order,
solutions display a global ODE type behavior, with domination of the normal
derivatives upon the tangential derivatives. This leads to the existence of a
universal, sharp blow-up profile in the normal direction at any GBU point, and
moreover implies that the behavior in the tangential direction is more
singular. On the other hand, it is known that any GBU solution admits a weak
continuation, under the form of a global viscosity solution. As another
consequence, we show that these viscosity solutions {\it generically} lose
boundary conditions after GBU. This result, as well as the above GBU profile,
were up to now essentially known only in one space-dimension.
| [
"math.AP"
] | math.AP | Analysis of PDEs | 205Analysis of PDEs
|
|
astro-ph/0412187 | Using the 2D multi-group, flux-limited diffusion version of the code
VULCAN/2D, that also incorporates rotation, we have calculated the collapse,
bounce, shock formation, and early post-bounce evolutionary phases of a
core-collapse supernova for a variety of initial rotation rates. This is the
first series of such multi-group calculations undertaken in supernova theory
with fully multi-D tools. We find that though rotation generates
pole-to-equator angular anisotropies in the neutrino radiation fields, the
magnitude of the asymmetries is not as large as previously estimated. Moreover,
we find that the radiation field is always more spherically symmetric than the
matter distribution, with its plumes and convective eddies. We present the
dependence of the angular anisotropy of the neutrino fields on neutrino
species, neutrino energy, and initial rotation rate. Only for our most rapidly
rotating model do we start to see qualitatively different hydrodynamics, but
for the lower rates consistent with the pre-collapse rotational profiles
derived in the literature the anisotropies, though interesting, are modest.
This does not mean that rotation does not play a key role in supernova
dynamics. The decrease in the effective gravity due to the centripetal effect
can be quite important. Rather, it means that when a realistic mapping between
initial and final rotational profiles and 2D multi-group
radiation-hydrodynamics are incorporated into collapse simulations the
anisotropy of the radiation fields may be only a secondary, not a pivotal
factor, in the supernova mechanism.
| [
"astro-ph"
] | astro-ph | Astrophysics | 463Astrophysics
|
|
2210.10087 | The 2022 Russia Ukraine War has led to many sanctions being placed on Russia
and Ukraine. The paper will discuss the impact the 2022 Russian Sanctions have
on agricultural food prices and hunger. The paper also uses Instrumental
Variable Analysis to find how Cryptocurrency and Bitcoin can be used to hedge
against the impact of sanctions. The 6 different countries analyzed in this
study including Bangladesh, El Salvador, Iran, Nigeria, Philippines, and South
Africa, all of which are heavy importers of wheat and corn. The paper shows
that although Bitcoin may be volatile compared to other local currencies, it
might be a good investment to safeguard assets since it is not correlated with
commodity prices.Furthermore, the study demonstrates that transaction volume
has a strong relationship with prices.
| [
"econ.GN",
"q-fin.EC"
] | econ.GN | q-fin.EC | General Economics;Economics | 2,608General Economics;Economics
|
2006.01810 | In this paper, we compute the motive of the character variety of
representations of the fundamental group of the complement of an arbitrary
torus knot into $SL_4(k)$, for any algebraically closed field $k$ of zero
characteristic. For that purpose, we introduce a stratification of the variety
in terms of the type of a canonical filtration attached to any representation.
This allows us to reduce the computation of the motive to a combinatorial
problem.
| [
"math.AG",
"math.GT"
] | math.AG | math.GT | Algebraic Geometry;Geometric Topology | 112Algebraic Geometry;Geometric Topology
|
2310.16771 | We introduce a new X-ray imaging technique to facilitate propagation-based
phase contrast of large, centimeter-sized samples. The diffracted X-ray
wavefield behind the sample is demagnified by asymmetric Bragg crystal optics,
thereby virtually increasing the propagation distance and thus enhancing the
image contrast. We demonstrate the significant increase in image contrast
compared to conventional phase contrast imaging at the same short physical
propagation distance. Additionally, the Bragg demagnifier enables the reduction
of image blur caused by the finite X-ray source size. In combination with a
subsequent Bragg magnifier, the method will allow for an even higher dose
efficiency, rendering this technique a potential candidate for, e.g., low-dose
(bio)medical diagnostics.
| [
"physics.optics",
"physics.app-ph",
"physics.med-ph"
] | physics.optics | physics.app-ph | Optics;Applied Physics;Medical Physics | 7,267longtail
|
hep-th/0111038 | We present a brief introduction to the construction of gauge theories on
noncommutative spaces with star products. Particular emphasis is given to
issues related to non-Abelian gauge groups and charge quantization. This talk
is based on joined work with B. Jurco, J. Madore, L. Moeller, S. Schraml and J.
Wess.
| [
"hep-th"
] | hep-th | High Energy Physics - Theory | 3,266High Energy Physics - Theory
|
|
hep-ph/0302070 | Using the QCD string approach the adiabatic potentials and spectra of b\bar
b-hybrid mesons are calculated. The results are compared to lattice studies.
| [
"hep-ph",
"hep-lat"
] | hep-ph | hep-lat | High Energy Physics - Phenomenology;High Energy Physics - Lattice | 3,218High Energy Physics - Phenomenology;High Energy Physics - Lattice
|
1401.7029 | A bar framework determined by a finite graph $G$ and configuration $\bf p$ in
$d$ space is universally rigid if it is rigid in any ${\mathbb R}^D \supset
{\mathbb R}^d$. We provide a characterization of universally rigidity for any
graph $G$ and any configuration ${\bf p}$ in terms of a sequence of affine
subsets of the space of configurations. This corresponds to a facial reduction
process for closed finite dimensional convex cones.
| [
"math.MG"
] | math.MG | Metric Geometry | 4,601Metric Geometry
|
|
1906.07381 | We present the results of three-dimensional special relativistic hydrodynamic
simulations of supernova ejecta with a powerful central energy source. We
assume spherical supernova ejecta freely expanding with the initial kinetic
energy of $10^{51}$ erg. We performed two simulations with different total
injected energies of $10^{51}$ and $10^{52}$ erg to see how the total injected
energy affects the subsequent evolution of the supernova ejecta. When the
injected energy well exceeds the initial kinetic energy of the supernova
ejecta, the hot bubble produced by the additional energy injection overwhelms
and penetrates the whole supernova ejecta, resulting in clumpy density
structure. For the smaller injected energy, on the other hand, the energy
deposition stops before the hot bubble breakout occurs, leaving the outer
envelope well-stratified. This qualitative difference may indicate that central
engine powered supernovae could be observed as two different populations, such
as supernovae with and without broad-line spectral features, depending on the
amount of the total injected energy with respect to the initial kinetic energy.
| [
"astro-ph.HE"
] | astro-ph.HE | High Energy Astrophysical Phenomena | 2,990High Energy Astrophysical Phenomena
|
|
2209.15478 | We propose a definition of tropical linear series that isolates some of the
essential combinatorial properties of tropicalizations of
not-necessarily-complete linear series on algebraic curves. The definition
combines the Baker-Norine notion of rank with the notion of tropical
independence and has the property that the restriction of a tropical linear
series of rank r to a connected subgraph is a tropical linear series of rank r.
We show that tropical linear series of rank 1 are finitely generated as
tropical modules and state a number of open problems related to algebraic,
combinatorial, and topological properties of higher rank tropical linear series
| [
"math.AG"
] | math.AG | Algebraic Geometry | 47Algebraic Geometry
|
|
1311.1914 | Thanks to significant improvements in high-resolution spectrographs and the
launch of dedicated space missions MOST, CoRoT and Kepler, the number of
subgiants and red-giant stars with detected oscillations has increased
significantly over the last decade. The amount of detail that can now be
resolved in the oscillation patterns does allow for in-depth investigations of
the internal structures of these stars. One phenomenon that plays an important
role in such studies are mixed modes. These are modes that carry information of
the inner radiative region as well as from the convective outer part of the
star allowing to probe different depths of the stars.
Here, we describe mixed modes and highlight some recent results obtained
using mixed modes observed in subgiants and red-giant stars.
| [
"astro-ph.SR"
] | astro-ph.SR | Solar and Stellar Astrophysics | 6,668Solar and Stellar Astrophysics
|
|
1709.09066 | Following the first two annual intensity mapping workshops at Stanford in
March 2016 and Johns Hopkins in June 2017, we report on the recent advances in
theory, instrumentation and observation that were presented in these meetings
and some of the opportunities and challenges that were identified looking
forward. With preliminary detections of CO, [CII], Lya and low-redshift 21cm,
and a host of experiments set to go online in the next few years, the field is
rapidly progressing on all fronts, with great anticipation for a flood of new
exciting results. This current snapshot provides an efficient reference for
experts in related fields and a useful resource for nonspecialists. We begin by
introducing the concept of line-intensity mapping and then discuss the broad
array of science goals that will be enabled, ranging from the history of star
formation, reionization and galaxy evolution to measuring baryon acoustic
oscillations at high redshift and constraining theories of dark matter,
modified gravity and dark energy. After reviewing the first detections reported
to date, we survey the experimental landscape, presenting the parameters and
capabilities of relevant instruments such as COMAP, mmIMe, AIM-CO, CCAT-p,
TIME, CONCERTO, CHIME, HIRAX, HERA, STARFIRE, MeerKAT/SKA and SPHEREx. Finally,
we describe recent theoretical advances: different approaches to modeling line
luminosity functions, several techniques to separate the desired signal from
foregrounds, statistical methods to analyze the data, and frameworks to
generate realistic intensity map simulations.
| [
"astro-ph.CO",
"astro-ph.GA",
"astro-ph.IM"
] | astro-ph.CO | astro-ph.GA | Cosmology and Nongalactic Astrophysics;Astrophysics of Galaxies;Instrumentation and Methods for Astrophysics | 1,738Cosmology and Nongalactic Astrophysics;Astrophysics of Galaxies;Instrumentation and Methods for Astrophysics
|
hep-th/0607110 | The nucleon's strange quark content comes from closed quark loops, and hence
should vanish at leading order in the traditional large $N_c$ (TLNC) limit.
Quark loops are not suppressed in the recently proposed orientifold large $N_c$
(OLNC) limit, and thus the strange quark content should be non-vanishing at
leading order. The Skyrme model is supposed to encode the large $N_c$ behavior
of baryons, and can be formulated for both of these large $N_c$ limits. There
is an apparent paradox associated with the large $N_c$ behavior of strange
quark matrix elements in the Skyrme model. The model only distinguishes between
the two large $N_c$ limits via the $N_c$ scaling of the couplings and the
Witten-Wess-Zumino term, so that a vanishing leading order strange matrix
element in the TLNC limit implies that it also vanishes at leading order in the
OLNC limit, contrary to the expectations based on the
suppression/non-suppression of quark loops. The resolution of this paradox is
that the Skyrme model does not include the most general type of meson-meson
interaction and, in fact, contains no meson-meson interactions which vanish for
the TLNC limit but not the OLNC. The inclusion of such terms in the model
yields the expected scaling for strange quark matrix elements.
| [
"hep-th",
"hep-ph",
"nucl-th"
] | hep-th | hep-ph | High Energy Physics - Theory;High Energy Physics - Phenomenology;Nuclear Theory | 3,351High Energy Physics - Theory;High Energy Physics - Phenomenology;Nuclear Theory
|
2210.04611 | We explain how the medial quandle of a classical or virtual link can be built
from the peripheral structure of the reduced Alexander module.
| [
"math.GT"
] | math.GT | Geometric Topology | 2,813Geometric Topology
|
|
0903.4887 | A novel self-consistent implementation of Hedin's GW perturbation theory is
introduced. This finite-temperature method uses Hartree-Fock wave functions to
represent Green's function. GW equations are solved with full potential linear
augmented plane wave (FLAPW) method at each iteration of a self-consistent
cycle. With our approach we are able to calculate total energy as a function of
the lattice parameter. Ground state properties calculated for Na, Al, and Si
compare well with experimental data.
| [
"cond-mat.str-el",
"cond-mat.other"
] | cond-mat.str-el | cond-mat.other | Strongly Correlated Electrons;Other Condensed Matter | 7,033Strongly Correlated Electrons;Other Condensed Matter
|
1806.03590 | Neural network models have shown promising results for text classification.
However, these solutions are limited by their dependence on the availability of
annotated data.
The prospect of leveraging resource-rich languages to enhance the text
classification of resource-poor languages is fascinating. The performance on
resource-poor languages can significantly improve if the resource availability
constraints can be offset. To this end, we present a twin Bidirectional Long
Short Term Memory (Bi-LSTM) network with shared parameters consolidated by a
contrastive loss function (based on a similarity metric). The model learns the
representation of resource-poor and resource-rich sentences in a common space
by using the similarity between their assigned annotation tags. Hence, the
model projects sentences with similar tags closer and those with different tags
farther from each other. We evaluated our model on the classification tasks of
sentiment analysis and emoji prediction for resource-poor languages - Hindi and
Telugu and resource-rich languages - English and Spanish. Our model
significantly outperforms the state-of-the-art approaches in both the tasks
across all metrics.
| [
"cs.CL"
] | cs.CL | Computation and Language | 1,168Computation and Language
|
|
1712.09079 | Our goal is to reveal how the $\alpha$ cluster amplitude is probed through
$\alpha$ knockout reactions depending on reaction conditions, e.g., the
incident energy. We consider $^{20}$Ne($p$,$p\alpha$)$^{16}$O and
$^{120}$Sn($p$,$p\alpha$)$^{116}$Cd at 100-400 MeV within the distorted wave
impulse approximation (DWIA) framework. We introduce a masking function which
shows how the reaction amplitude in the nuclear interior is suppressed and
defines the probed region of the $\alpha$ cluster wave function. It is clearly
shown by means of the masking function that the $\alpha$ knockout reaction
probes the $\alpha$ cluster amplitude in the nuclear surface region, which is
the direct measure of well-developed $\alpha$ cluster states. A simplified form
of the masking function is introduced and the incident energy dependence of the
masking effect is investigated. $\alpha$ knockout reaction can probe the
$\alpha$ cluster amplitude in the nuclear surface region by choosing proper
kinematics owing to the masking effect originated from absorptions of
distorting potentials, and is a suitable method to investigate how $\alpha$
cluster states are spatially developed.
| [
"nucl-th"
] | nucl-th | Nuclear Theory | 4,876Nuclear Theory
|
|
astro-ph/9408079 | Paramagnetic alignment of fractal suprathermally rotating grains is
discussed. It is shown that if the concentration of H$_{2}$formation sites is
low and resurfacing is active, fractal structure of grains enhances their
alignment. Studying the influence of grain surface physics and chemistry on the
alignment we found that there exist two critical values of grain sizes, and the
alignment of smaller grains is expected to decrease as compared to the
predictions of the Purcell's theory (1979). One of the critical sizes is due to
intensified poisoning of active sites, while the other is a result of a finite
value of the imaginary part of magnetic susceptibility in the limit of high
angular velocities. On the contrary, if active sites completely cover grain
surface, suprathermal rotation, and therefore efficient alignment, is possible
only for a limited range of grain sizes.
| [
"astro-ph"
] | astro-ph | Astrophysics | 463Astrophysics
|
|
1003.2611 | Morphological properties of strained epitaxial films are examined through a
mesoscopic approach developed to incorporate both the film crystalline
structure and standard continuum theory. Film surface profiles and properties,
such as surface energy, liquid-solid miscibility gap and interface thickness,
are determined as a function of misfit strains and film elastic modulus. We
analyze the stress-driven instability of film surface morphology that leads to
the formation of strained islands. We find a universal scaling relationship
between the island size and misfit strain which shows a crossover from the
well-known continuum elasticity result at the weak strain to a behavior
governed by a "perfect" lattice relaxation condition. The strain at which the
crossover occurs is shown to be a function of liquid-solid interfacial
thickness, and an asymmetry between tensile and compressive strains is
observed. The film instability is found to be accompanied by mode coupling of
the complex amplitudes of the surface morphological profile, a factor
associated with the crystalline nature of the strained film but absent in
conventional continuum theory.
| [
"cond-mat.mtrl-sci"
] | cond-mat.mtrl-sci | Materials Science | 4,287Materials Science
|
|
1808.01579 | In the stable general linear group over an arbitrary field, we prove that
every element with determinant $\pm 1$ is the product of three involutions, and
of no less in general. We also obtain several results of the same flavor, with
applications to decompositions of automorphisms of an infinite-dimensional
vector space that are scalar multiples of finite-rank perturbations of the
identity.
| [
"math.RA",
"math.GR"
] | math.RA | math.GR | Rings and Algebras;Group Theory | 6,294Rings and Algebras;Group Theory
|
1504.06065 | Starless molecular cores are natural laboratories for interstellar molecular
chemistry research. The chemistry of ices in such objects was investigated with
a three-phase (gas, surface, and mantle) model. We considered the center part
of five starless cores, with their physical conditions derived from
observations. The ice chemistry of oxygen, nitrogen, sulfur, and complex
organic molecules (COMs) was analyzed. We found that an ice-depth dimension,
measured, e.g., in monolayers, is essential for modeling of chemistry in
interstellar ices. Particularly, the H2O:CO:CO2:N2:NH3 ice abundance ratio
regulates the production and destruction of minor species. It is suggested that
photodesorption during core collapse period is responsible for high abundance
of interstellar H2O2 and O2H, and other species synthesized on the surface. The
calculated abundances of COMs in ice were compared to observed gas-phase
values. Smaller activation barriers for CO and H2CO hydrogenation may help
explain the production of a number of COMs. The observed abundance of methyl
formate HCOOCH3 could be reproduced with a 1kyr, 20K temperature spike.
Possible desorption mechanisms, relevant for COMs, are gas turbulence (ice
exposure to interstellar photons) or a weak shock within the cloud core (grain
collisions). To reproduce the observed COM abundances with the present 0D
model, 1-10% of ice mass needs to be sublimated. We estimate that the lifetime
for starless cores likely does not exceed 1Myr. Taurus cores are likely to be
younger than their counterparts in most other clouds.
| [
"astro-ph.GA",
"physics.chem-ph"
] | astro-ph.GA | physics.chem-ph | Astrophysics of Galaxies;Chemical Physics | 468Astrophysics of Galaxies;Chemical Physics
|
2103.14308 | In an environment with high-density neutrinos formed in a core-collapse
supernova (CCSN), the neutrinos exhibit nonlinear and complex oscillation
behaviors due to their self-interactions. The onset of this nonlinear
oscillation can be investigated by linearizing the evolution equation for small
perturbations around the flavor eigenstates. While the condition under which
the flavor eigenstates are unstable has been investigated in many studies, how
the perturbations evolve in spacetime has yet to be elucidated. In this paper,
we analytically and correctly derive the asymptotic behaviors of the linear
perturbations in 4-dimensional spacetime in the linear regime for a 2-beam
neutrino model using the recently proposed Lefschetz thimble formulation. The
result suggests that the perturbations grow in the directions between the two
neutrino beams. We also briefly discuss the possible effects of neutrino flavor
conversion on the explosion mechanism of a CCSN. In particular, the result
implies that the flavor instability in the preshock region may propagate into
the postshock region, contrary to the previous study focusing on the group
velocity in 1-dimensional space. How to treat the case of a more realistic
continuous spectrum is also discussed.
| [
"hep-ph",
"astro-ph.HE"
] | hep-ph | astro-ph.HE | High Energy Physics - Phenomenology;High Energy Astrophysical Phenomena | 3,187High Energy Physics - Phenomenology;High Energy Astrophysical Phenomena
|
astro-ph/0110474 | Two types of models for the formation of semi-periodic concentric multiple
shells (M-shells) around asymptotic giant branch (AGB) stars and in planetary
nebulae are compared against observations. Models that attribute the M-shells
to processes in an extended wind acceleration zone around AGB stars result in
an optically thick acceleration zone, which reduces the acceleration efficiency
in outer parts of the extended acceleration zone. This makes such models an
unlikely explanation for the formation of M-shells. Models which attribute the
M-shell to semi-periodic variation in one or more stellar properties are most
compatible with observations. The only stellar variation models on time scales
of 50-1500 years that have been suggested are based on an assumed solar-like
magnetic cycle. Although ad-hoc, the magnetic cycle assumption fits naturally
into the increasingly popular view that magnetic activity plays a role in
shaping the wind from upper AGB stars.
| [
"astro-ph"
] | astro-ph | Astrophysics | 463Astrophysics
|
|
1501.05179 | We analyze random unitary evolution of the qubit within memory kernel
approach. We provide sufficient conditions which guarantee that the
corresponding memory kernel generates physically legitimate quantum evolution.
Interestingly, we are able to recover several well known examples and generate
new classes of nontrivial qubit evolution. Surprisingly, it turns out that
quantum evolution with memory kernel generated by our approach gives rise to
vanishing non-Markovianity measure based on the distinguishability of quantum
states.
| [
"quant-ph"
] | quant-ph | Quantum Physics | 5,985Quantum Physics
|
|
1403.1290 | We describe a method based on precision magnetometry that can extend the
search for axion-mediated spin-dependent forces by several orders of magnitude.
By combining techniques used in nuclear magnetic resonance and short-distance
tests of gravity, our approach can substantially improve upon current
experimental limits set by astrophysics, and probe deep into the theoretically
interesting regime for the Peccei-Quinn (PQ) axion. Our method is sensitive to
PQ axion decay constants between 10^9 and 10^12 GeV or axion masses between
10^-6 and 10^-3 eV, independent of the cosmic axion abundance.
| [
"hep-ph"
] | hep-ph | High Energy Physics - Phenomenology | 3,129High Energy Physics - Phenomenology
|
|
1507.06927 | The use of free and open source software (OSS) is gaining momentum due to the
ever increasing availability and use of the Internet. Organizations are also
now adopting open source software, despite some reservations, in particular
regarding the provision and availability of support. Some of the biggest
concerns about free and open source software are post release software defects
and their rectification, management of dynamic requirements and support to the
users. A common belief is that there is no appropriate support available for
this class of software. A contradictory argument is that due to the active
involvement of Internet users in online forums, there is in fact a large
resource available that communicates and manages the provision of support. The
research model of this empirical investigation examines the evidence available
to assess whether this commonly held belief is based on facts given the current
developments in OSS or simply a myth, which has developed around OSS
development. We analyzed a dataset consisting of 1880 open source software
projects covering a broad range of categories in this investigation. The
results show that online forums play a significant role in managing software
defects, implementation of new requirements and providing support to the users
in open source software and have become a major source of assistance in
maintenance of the open source projects.
| [
"cs.SE"
] | cs.SE | Software Engineering | 6,626Software Engineering
|
|
cond-mat/0703141 | ZnCu$_{3}$(OH)$_{6}$Cl$_{2}$ ($S=1/2$) is a promising new candidate for an
ideal Kagom\'e Heisenberg antiferromagnet, because there is no magnetic phase
transition down to $\sim$50 mK. We investigated its local magnetic and lattice
environments with NMR techniques. We demonstrate that the intrinsic local spin
susceptibility {\it decreases} toward T=0, but that slow freezing of the
lattice near $\sim$50 K, presumably associated with OH bonds, contributes to a
large increase of local spin susceptibility and its distribution. Spin dynamics
near T=0 obey a power-law behavior in high magnetic fields.
| [
"cond-mat.str-el"
] | cond-mat.str-el | Strongly Correlated Electrons | 6,979Strongly Correlated Electrons
|
|
2308.11625 | We construct a highly-symmetric periodic orbit of six bodies in three
dimensions. In this orbit, binary collisions occur at the origin in a regular
periodic fashion, rotating between pairs of bodies located on the coordinate
axes. Regularization of the collisions in the orbit is achieved by an extension
of the Levi-Civita method. Initial conditions for the orbit are found
numerically. In contrast to an earlier periodic collision-based orbit in three
dimensions, this orbit is shown to be unstable.
| [
"math.DS"
] | math.DS | Dynamical Systems | 2,265Dynamical Systems
|
|
1803.08723 | We prove the local Lipschitz continuity and the higher differentiability of
local minimizers of integral functionals with non autonomous integrand which is
degenerate convex with respect to the gradient variable. The main novelty here
is that the results are obtained assuming that the coefficients have weak
derivative in an almost critical Zygmund class and the datum f is assumed to
belong to the same Zygmund class.
| [
"math.AP"
] | math.AP | Analysis of PDEs | 205Analysis of PDEs
|
|
2009.07813 | Primordial Black Holes (PBH) with masses of order $10-30 M_\odot$ have been
proposed as a possible explanation of the gravitational waves emission events
recently discovered by the LIGO observatory. If true, then PBHs would
constitute a sizeable fraction of the dark matter component in the Universe.
Using a series of cosmological N-body simulations which include both dark
matter and a variable fraction of PBHs ranging from $f_{PBH} = 10^{-4}$ to
$f_{PBH} = 1$, we analyse the processes of formation and disruption of
gravitationally bound PBH pairs, as well as the merging of both bound and
unbound pairs, and estimate the probabilities of such events. We show that they
are in good agreement with the constrains to the PBH abundance obtained by the
LIGO and other research groups. We find that pair stability, while being a main
factor responsible for the merger rate, is significantly affected by the
effects of dark matter halo formation and clustering. As a side result, we also
evaluate the effects of numerical errors in the stability of bound pairs, which
can be useful for future research using this methodology.
| [
"astro-ph.CO",
"gr-qc",
"hep-ph"
] | astro-ph.CO | gr-qc | Cosmology and Nongalactic Astrophysics;General Relativity and Quantum Cosmology;High Energy Physics - Phenomenology | 1,746Cosmology and Nongalactic Astrophysics;General Relativity and Quantum Cosmology;High Energy Physics - Phenomenology
|
1411.3956 | The synaptic connectivity of cortical networks features an overrepresentation
of certain wiring motifs compared to simple random-network models. This
structure is shaped, in part, by synaptic plasticity that promotes or
suppresses connections between neurons depending on their spiking activity.
Frequently, theoretical studies focus on how feedforward inputs drive
plasticity to create this network structure. We study the complementary
scenario of self-organized structure in a recurrent network, with spike
timing-dependent plasticity driven by spontaneous dynamics. We develop a
self-consistent theory that describes the evolution of network structure by
combining fast spiking covariance with a fast-slow theory for synaptic weight
dynamics. Through a finite-size expansion of network dynamics, we obtain a
low-dimensional set of nonlinear differential equations for the evolution of
two-synapse connectivity motifs. With this theory in hand, we explore how the
form of the plasticity rule drives the evolution of microcircuits in cortical
networks. When potentiation and depression are in approximate balance, synaptic
dynamics depend on the frequency of weighted divergent, convergent, and chain
motifs. For additive, Hebbian STDP, these motif interactions create
instabilities in synaptic dynamics that either promote or suppress the initial
network structure. Our work provides a consistent theoretical framework for
studying how spiking activity in recurrent networks interacts with synaptic
plasticity to determine network structure.
| [
"q-bio.NC"
] | q-bio.NC | Neurons and Cognition | 4,806Neurons and Cognition
|
|
2003.05003 | Objectives: We aim to assess the impact of temperature and relative humidity
on the transmission of COVID-19 across communities after accounting for
community-level factors such as demographics, socioeconomic status, and human
mobility status. Design: A retrospective cross-sectional regression analysis
via the Fama-MacBeth procedure is adopted. Setting: We use the data for
COVID-19 daily symptom-onset cases for 100 Chinese cities and COVID-19 daily
confirmed cases for 1,005 U.S. counties. Participants: A total of 69,498 cases
in China and 740,843 cases in the U.S. are used for calculating the effective
reproductive numbers. Primary outcome measures: Regression analysis of the
impact of temperature and relative humidity on the effective reproductive
number (R value). Results: Statistically significant negative correlations are
found between temperature/relative humidity and the effective reproductive
number (R value) in both China and the U.S. Conclusions: Higher temperature and
higher relative humidity potentially suppress the transmission of COVID-19.
Specifically, an increase in temperature by 1 degree Celsius is associated with
a reduction in the R value of COVID-19 by 0.026 (95% CI [-0.0395,-0.0125]) in
China and by 0.020 (95% CI [-0.0311, -0.0096]) in the U.S.; an increase in
relative humidity by 1% is associated with a reduction in the R value by 0.0076
(95% CI [-0.0108,-0.0045]) in China and by 0.0080 (95% CI [-0.0150,-0.0010]) in
the U.S. Therefore, the potential impact of temperature/relative humidity on
the effective reproductive number alone is not strong enough to stop the
pandemic.
| [
"q-bio.PE"
] | q-bio.PE | Populations and Evolution | 5,627Populations and Evolution
|
|
1306.2954 | Observations suggest that a large fraction of black hole growth occurs in
normal star-forming disk galaxies. Here we describe simulations of black hole
accretion in isolated disk galaxies with sufficient resolution (~5 pc) to track
the formation of giant molecular clouds that feed the black hole. Black holes
in z=2 gas-rich disks (fgas=50%) occasionally undergo ~10 Myr episodes of
Eddington-limited accretion driven by stochastic collisions with massive, dense
clouds. We predict that these gas-rich disks host weak AGNs 1/4 of the time,
and moderate/strong AGNs 10% of the time. Averaged over 100 Myr timescales and
the full distribution of accretion rates, the black holes grow at a few per
cent of the Eddington limit -- sufficient to match observations and keep the
galaxies on the MBH-Mbulge relation. This suggests that dense cloud accretion
in isolated z=2 disks could dominate cosmic black hole growth. In z=0 disks
with fgas=10%, Eddington-limited growth is extremely rare because typical gas
clouds are smaller and more susceptible to disruption by AGN feedback. This
results in an average black hole growth rate in high-fgas galaxies that is up
to 1000 times higher than that in low-fgas galaxies. In all our simulations,
accretion shows variability by factors of 10^4 on a variety of time scales,
with variability at 1 Myr scales driven by the structure of the interstellar
medium.
| [
"astro-ph.CO"
] | astro-ph.CO | Cosmology and Nongalactic Astrophysics | 1,725Cosmology and Nongalactic Astrophysics
|
|
1008.1962 | Avoiding the loss of coherence of quantum mechanical states is an important
prerequisite for quantum information processing. Dynamical decoupling (DD) is
one of the most effective experimental methods for maintaining coherence,
especially when one can access only the qubit-system and not its environment
(bath). It involves the application of pulses to the system whose net effect is
a reversal of the system-environment interaction. In any real system, however,
the environment is not static, and therefore the reversal of the
system-environment interaction becomes imperfect if the spacing between
refocusing pulses becomes comparable to or longer than the correlation time of
the environment. The efficiency of the refocusing improves therefore if the
spacing between the pulses is reduced. Here, we quantify the efficiency of
different DD sequences in preserving different quantum states. We use 13C
nuclear spins as qubits and an environment of 1H nuclear spins as the
environment, which couples to the qubit via magnetic dipole-dipole couplings.
Strong dipole-dipole couplings between the proton spins result in a rapidly
fluctuating environment with a correlation time of the order of 100 us. Our
experimental results show that short delays between the pulses yield better
performance if they are compared with the bath correlation time. However, as
the pulse spacing becomes shorter than the bath correlation time, an optimum is
reached. For even shorter delays, the pulse imperfections dominate over the
decoherence losses and cause the quantum state to decay.
| [
"quant-ph",
"cond-mat.mes-hall",
"physics.chem-ph",
"physics.gen-ph"
] | quant-ph | cond-mat.mes-hall | Quantum Physics;Mesoscale and Nanoscale Physics;Chemical Physics;General Physics | 7,267longtail
|