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arxiv_dataset-104001810.08813 | On the semigroup ring of holomorphic Artin L-functions
math.NT
Let $K/\mathbb Q$ be a finite Galois extension and let $\chi_1,\ldots,\chi_r$
be the irreducible characters of the Galois group $G:=Gal(K/\mathbb Q)$. Let
$f_1:=L(s,\chi_1),\ldots,f_r:=L(s,\chi_r)$ be their associated Artin
L-functions. For $s_0\in \mathbb C\setminus\{1\}$, we denote $Hol(s_0)$ the
semigroup of Artin $L$-functions, holomorphic at $s_0$. Let $\mathbb F$ be a
field with $\mathbb C \subseteq \mathbb F \subseteq \mathcal M_{<1}:=$ the
field of meromorphic functions of order $<1$. We note that the semigroup ring
$\mathbb F[Hol(s_0)]$ is isomorphic to a toric ring $\mathbb F[H(s_0)]\subseteq
\mathbb F[x_1,\ldots,x_r]$, where $H(s_0)$ is an affine subsemigroup of
$\mathbb N^r$ minimally generated by at least $r$ elements, and we describe
$\mathbb F[H(s_0)]$ when the toric ideal $I_{H(s_0)}=(0)$. Also, we describe
$\mathbb F[H(s_0)]$ and $I_{H(s_0)}$ when $f_1,\ldots,f_r$ have only simple
zeros and simple poles at $s_0$.
| arxiv topic:math.NT |
arxiv_dataset-104011810.08913 | Integrals derived from the doubling method
math.NT
In this note, we use a basic identity, derived from the generalized doubling
integrals of \cite{C-F-G-K1}, in order to explain the existence of various
global Rankin-Selberg integrals for certain $L$-functions. To derive these
global integrals, we use the identities relating Eisenstein series in
\cite{G-S}, together with the process of exchanging roots. We concentrate on
several well known examples, and explain how to obtain them from the basic
identity. Using these ideas, we also show how to derive a new global integral.
| arxiv topic:math.NT |
arxiv_dataset-104021810.09013 | On a linear functional for infinitely divisible moving average random
fields
math.PR math.ST stat.TH
Given a low-frequency sample of the infinitely divisible moving average
random field $\{\int_{\mathbb{R}^d}f(t-x)\Lambda (dx), t\in \mathbb{R}^d\}$, in
[13] we proposed an estimator $\hat{uv_0}$ for the function $\mathbb{R}\ni
x\mapsto u(x)v_0(x)=(uv_0)(x)$, with $u(x)=x$ and $v_0$ being the L\'{e}vy
density of the integrator random measure $\Lambda$. In this paper, we study
asymptotic properties of the linear functional $L^2(\mathbb{R})\ni v\mapsto
\left \langle v,\hat{uv_0}\right \rangle_{L^2(\mathbb{R})}$, if the (known)
kernel function $f$ has a compact support. We provide conditions that ensure
consistency (in mean) and prove a central limit theorem for it.
| arxiv topic:math.PR math.ST stat.TH |
arxiv_dataset-104031810.09113 | The Bregman chord divergence
cs.LG stat.ML
Distances are fundamental primitives whose choice significantly impacts the
performances of algorithms in machine learning and signal processing. However
selecting the most appropriate distance for a given task is an endeavor.
Instead of testing one by one the entries of an ever-expanding dictionary of
{\em ad hoc} distances, one rather prefers to consider parametric classes of
distances that are exhaustively characterized by axioms derived from first
principles. Bregman divergences are such a class. However fine-tuning a Bregman
divergence is delicate since it requires to smoothly adjust a functional
generator. In this work, we propose an extension of Bregman divergences called
the Bregman chord divergences. This new class of distances does not require
gradient calculations, uses two scalar parameters that can be easily tailored
in applications, and generalizes asymptotically Bregman divergences.
| arxiv topic:cs.LG stat.ML |
arxiv_dataset-104041810.09213 | Digital Quantum Simulation of Hadronization in Yang-Mills Theory
quant-ph hep-th
A quantum algorithm of SU(N) Yang-Mills theory is formulated in terms of
quantum circuits. It can nonperturbatively calculate the Dyson series and
scattering amplitudes with polynomial complexity. The gauge fields in the
interaction picture are discretized on the same footing with the lattice
fermions in momentum space to avoid the fermion doubling and the gauge symmetry
breaking problems. Applying the algorithm to the quantum simulation of quantum
chromodynamics, the quark and gluon's wave functions evolved from the initial
states by the interactions can be observed and the information from wave
functions can be extracted at any discrete time. This may help us understand
the natures of the hadronization which has been an outstanding question of
significant implication on high energy phenomenological studies.
| arxiv topic:quant-ph hep-th |
arxiv_dataset-104051810.09313 | Geometric inequalities for critical metrics of the volume functional
math.DG
In this article, we investigate the geometry of critical metrics of the
volume functional on an $n$-dimensional compact manifold with (possibly
disconnected) boundary. We establish sharp estimates to the mean curvature and
area of the boundary components of critical metrics of the volume functional on
a compact manifold. In addition, localized version estimates to the mean
curvature and area of the boundary of critical metrics are also obtained.
| arxiv topic:math.DG |
arxiv_dataset-104061810.09413 | EFT approach to the electron Electric Dipole Moment at the two-loop
level
hep-ph
The ACME collaboration has recently reported a new bound on the electric
dipole moment (EDM) of the electron, $|d_e|< 1.1 \times 10^{-29}\, {\rm e\cdot
cm}$ at 90$\%$ confidence level, reaching an unprecedented accuracy level. This
can translate into new relevant constraints on theories beyond the SM laying at
the TeV scale, even when they contribute to the electron EDM at the two-loop
level. We use the EFT approach to classify these corrections, presenting the
contributions to the anomalous dimension of the CP-violating dipole operators
of the electron up to the two-loop level. Selection rules based on helicity and
CP play an important role to simplify this analysis. We use this result to
provide new bounds on BSM with leptoquarks, extra Higgs, or constraints in
sectors of the MSSM and composite Higgs models. The new ACME bound pushes
natural theories significantly more into fine-tune territory, unless they have
a way to accidentally preserve CP.
| arxiv topic:hep-ph |
arxiv_dataset-104071810.09513 | Transient stratification force on particles crossing a density interface
physics.flu-dyn
We perform a series of experiments to measure Lagrangian trajectories of
settling and rising particles as they traverse a density interface of thickness
$h$ using an index-matched water-salt-ethanol solution. The experiments confirm
the substantial deceleration that particles experience as a result of the
additional force exerted on the particle due to the sudden change in density.
This stratification force is calculated from the measurement data for all
particle trajectories. In the absence of suitable parameterizations in the
literature, a simple phenomenological model is developed which relies on
parameterizations of the effective wake volume and recovery time scale. The
model accurately predicts the particle trajectories obtained in our experiments
and those of \cite{Fernando1999}. Furthermore, the model demonstrates that the
problem depends on four key parameters, namely the entrance Reynolds number
$Re_1$, entrance Froude number $Fr$, particle to fluid density ratio
$\rho_p/\rho_f$, and relative interface thickness $h/a$.
| arxiv topic:physics.flu-dyn |
arxiv_dataset-104081810.09613 | Refining Santa: An Exercise in Efficient Synchronization
cs.PL cs.LO cs.SE
The Santa Claus Problem is an intricate exercise for concurrent programming.
This paper outlines the refinement steps to develop a highly efficient
implementation with concurrent objects, starting from a simple specification.
The efficiency of the implementation is compared to those in other languages.
| arxiv topic:cs.PL cs.LO cs.SE |
arxiv_dataset-104091810.09713 | Complex Langevin: Boundary terms and application to QCD
hep-lat hep-th
We employ the Complex Langevin method for simulation of complex-valued
actions. First, we show how to test for convergence of the method by
explicitely computing boundary terms and demonstrate this in a model. Then we
investigate the deconfinement phase transition of QCD with $N_f=2$
Wilson-fermions using the Complex Langevin Method and. We give preliminary
results for the transition temperatures up to $\mu/T_c(\mu=0)\approx 5$ and
compute the curvature coefficient $\kappa_2$.
| arxiv topic:hep-lat hep-th |
arxiv_dataset-104101810.09813 | New type of solutions of Yang-Baxter equations, quantum entanglement and
related physical models
quant-ph math-ph math.MP
Starting from the Kauffman-Lomonaco braiding matrix transforming the natural
basis to Bell states, the spectral parameter describing the entanglement is
introduced through Yang-Baxterization. It gives rise to a new type of solutions
for Yang-Baxter equation, called the type-II that differs from the familiar
solution called type-I of YBE associated with the usual chain models. The
Majorana fermionic version of type-II yields the Kitaev Hamiltonian. The
introduced $\ell_1$ -norm leads to the maximum of the entanglement by taking
the extreme value and shows that it is related to the Wigner's D-function.
Based on the Yang-Baxter equation the 3-body S-Matrix for type-II is explicitly
given. Different from the type-I solution, the type-II solution of YBE should
be considered in describing quantum information. The idea is further extended
to $\mathbb{Z}_3$ parafermion model based on $SU(3)$ principal representation.
The type-II is in difference from the familiar type-I in many respects. For
example, the quantities corresponding to velocity in the chain models obey the
Lorentzian additivity $\frac{u+v}{1+uv}$ rather than Galilean rule $(u+v)$.
Most possibly, for the type-II solutions of YBE there may not exist RTT
relation. Further more, for $\mathbb{Z}_3$ parafermion model we only need the
rational Yang-Baxterization, which seems like trigonometric. Similar
discussions are also made in terms of generalized Yang-Baxter equation with
three spin spaces $\{1,\frac{1}{2},\frac{1}{2}\}$.
| arxiv topic:quant-ph math-ph math.MP |
arxiv_dataset-104111810.09913 | Most Probable Evolution Trajectories in a Genetic Regulatory System
Excited by Stable L\'evy Noise
q-bio.MN q-bio.SC
We study the most probable trajectories of the concentration evolution for
the transcription factor activator in a genetic regulation system, with
non-Gaussian stable L\'evy noise in the synthesis reaction rate taking into
account. We calculate the most probable trajectory by spatially maximizing the
probability density of the system path, i.e., the solution of the associated
nonlocal Fokker-Planck equation. We especially examine those most probable
trajectories from low concentration state to high concentration state (i.e.,
the likely transcription regime) for certain parameters, in order to gain
insights into the transcription processes and the tipping time for the
transcription likely to occur. This enables us: (i) to visualize the progress
of concentration evolution (i.e., observe whether the system enters the
transcription regime within a given time period); (ii) to predict or avoid
certain transcriptions via selecting specific noise parameters in particular
regions in the parameter space. Moreover, we have found some peculiar or
counter-intuitive phenomena in this gene model system, including (a) a smaller
noise intensity may trigger the transcription process, while a larger noise
intensity can not, under the same asymmetric L\'evy noise. This phenomenon does
not occur in the case of symmetric L\'evy noise; (b) the symmetric L\'evy
motion always induces transition to high concentration, but certain asymmetric
L\'evy motions do not trigger the switch to transcription. These findings
provide insights for further experimental research, in order to achieve or to
avoid specific gene transcriptions, with possible relevance for medical
advances.
| arxiv topic:q-bio.MN q-bio.SC |
arxiv_dataset-104121810.10013 | Holographic duals of 6d RG flows
hep-th
A notable class of superconformal theories (SCFTs) in six dimensions is
parameterized by an integer $N$, an ADE group $G$, and two nilpotent elements
$\mu_\mathrm{L,R}$ in $G$. Nilpotent elements have a natural partial ordering,
which has been conjectured to coincide with the hierarchy of
renormalization-group flows among the SCFTs. In this paper we test this
conjecture for $G=\mathrm{SU}(k)$, where AdS$_7$ duals exist in IIA. We work
with a seven-dimensional gauged supergravity, consisting of the gravity
multiplet and two $\mathrm{SU}(k)$ non-Abelian vector multiplets. We show that
this theory has many supersymmetric AdS$_7$ vacua, determined by two nilpotent
elements, which are naturally interpreted as IIA AdS$_7$ solutions. The BPS
equations for domain walls connecting two such vacua can be solved
analytically, up to a Nahm equation with certain boundary conditions. The
latter admit a solution connecting two vacua if and only if the corresponding
nilpotent elements are related by the natural partial ordering, in agreement
with the field theory conjecture.
| arxiv topic:hep-th |
arxiv_dataset-104131810.10113 | How different is the core of $^{25}$F from $^{24}$O$_{g.s.}$?
nucl-ex nucl-th
The neutron-shell structure of $^{25}$F was studied using quasi-free (p,2p)
knockout reaction at 270A MeV in inverse kinematics. The sum of spectroscopic
factors of $\pi$0d$_{5/2}$ orbital is found to be $1.0 \pm 0.3$. However, the
spectroscopic factor for the ground-state to ground-state transition ($^{25}$F,
$^{24}$O$_{g.s.}$) is only $0.36\pm 0.13$, and $^{24}$O excited states are
produced from the 0d$_{5/2}$ proton knockout. The result shows that the
$^{24}$O core of $^{25}$F nucleus significantly differs from a free $^{24}$O
nucleus, and the core consists of 35% $^{24}$O$_{g.s}$. and 65% excited
$^{24}$O.
| arxiv topic:nucl-ex nucl-th |
arxiv_dataset-104141810.10213 | The Langevin diffusion as a continuous-time model of animal movement and
habitat selection
stat.AP stat.ME
1. The utilisation distribution describes the relative probability of use of
a spatial unit by an animal. It is natural to think of it as the long-term
consequence of the animal's short-term movement decisions: it is the
accumulation of small displacements which, over time, gives rise to global
patterns of space use. However, most utilisation distribution models either
ignore the underlying movement, assuming the independenceof observed locations,
or are based on simplistic Brownian motion movement rules. 2. We introduce a
new continuous-time model of animal movement, based on the Langevin diffusion.
This stochastic process has an explicit stationary distribution, conceptually
analogous to the idea of the utilisation distribution, and thus provides an
intuitive framework to integrate movement and space use. We model the
stationary (utilisation) distribution with a resource selection function to
link the movement to spatial covariates, and allow inference into habitat
selection. 3. Standard approximation techniques can be used to derive the
pseudo-likelihood of the Langevin diffusion movement model, and to estimate
habitat preference and movement parameters from tracking data. We investigate
the performance of the method on simulated data, and discuss its sensitivity to
the time scale of the sampling. We present an example of its application to
tracking data of Stellar sea lions (Eumetopiasjubatus). 4. Due to its
continuous-time formulation, this method can be applied to irregular telemetry
data. It provides a rigorous framework to estimate long-term habitat selection
from correlated movement data.
| arxiv topic:stat.AP stat.ME |
arxiv_dataset-104151810.10313 | First and Second Order Shape Optimization based on Restricted Mesh
Deformations
math.OC
We consider shape optimization problems subject to elliptic partial
differential equations. In the context of the finite element method, the
geometry to be optimized is represented by the computational mesh, and the
optimization proceeds by repeatedly updating the mesh node positions. It is
well known that such a procedure eventually may lead to a deterioration of mesh
quality, or even an invalidation of the mesh, when interior nodes penetrate
neighboring cells. We examine this phenomenon, which can be traced back to the
ineptness of the discretized objective when considered over the space of mesh
node positions. As a remedy, we propose a restriction in the admissible mesh
deformations, inspired by the Hadamard structure theorem. First and second
order methods are considered in this setting. Numerical results show that mesh
degeneracy can be overcome, avoiding the need for remeshing or other
strategies. FEniCS code for the proposed methods is available on GitHub.
| arxiv topic:math.OC |
arxiv_dataset-104161810.10413 | Thorium in solar twins: implications for habitability in rocky planets
astro-ph.SR astro-ph.EP
We have investigated the thorium (Th) abundance in a sample of 53 thin disc
solar twins covering a wide range of ages. These data provide constrains on the
mantle energy budget of terrestrial planets that can be formed over the
evolution of the Galaxy's thin disc. We have estimated Th abundances with an
average precision of 0.025\,dex (in both [Th/H] and [Th/Fe]) through
comprehensive spectral synthesis of a Th\,II line present at 4019.1290\,{\AA},
using very high resolution (R\,=\,115,000) high quality HARPS spectra obtained
at the ESO La Silla Observatory. We have confirmed that there is a large energy
budget from Th decay for maintaining mantle convection inside potential rocky
planets around solar twins, from the Galactic thin disc formation until now,
because the pristine [Th/H]$_{\rm ZAMS}$ is super-solar on average under a
uniform dispersion of 0.056\,dex (varying from +0.037 up to +0.138\,dex based
on linear fits against isochrone stellar age). Comparing to neodymium (Nd) and
europium (Eu), two others neutron-capture elements, the stellar pristine
abundance of Th follows Eu along the Galactic thin disc evolution, but it does
not follow Nd, probably because neodymium has a significant contribution from
the $s$-process (about 60\,per\,cent).
| arxiv topic:astro-ph.SR astro-ph.EP |
arxiv_dataset-104171810.10513 | Between-Ride Routing for Private Transportation Services
cs.SY
Spurred by the growth of transportation network companies and increasing data
capabilities, vehicle routing and ride-matching algorithms can improve the
efficiency of private transportation services. However, existing routing
solutions do not address where drivers should travel after dropping off a
passenger and before receiving the next passenger ride request, i.e., during
the between-ride period. We address this problem by developing an efficient
algorithm to find the optimal policy for drivers between rides in order to
maximize driver profits. We model the road network as a graph, and we show that
the between-ride routing problem is equivalent to a stochastic shortest path
problem, an infinite dynamic program with no discounting. We prove under
reasonable assumptions that an optimal routing policy exists that avoids
cycles; policies of this type can be efficiently found. We present an iterative
approach to find an optimal routing policy. Our approach can account for
various factors, including the frequency of passenger ride requests at
different locations, traffic conditions, and surge pricing. We demonstrate the
effectiveness of the approach by implementing it on road network data from
Boston and New York City.
| arxiv topic:cs.SY |
arxiv_dataset-104181810.10613 | Convergent and divergent beam electron holography and reconstruction of
adsorbates on free-standing two-dimensional crystals
cond-mat.mtrl-sci cond-mat.mes-hall physics.ins-det
Van der Waals heterostructures have been lately intensively studied because
they offer a large variety of properties that can be controlled by selecting 2D
materials and their sequence in the stack. The exact arrangement of the layers
as well as the exact arrangement of the atoms within the layers, both are
important for the properties of the resulting device. Recently it has been
demonstrated that convergent beam electron diffraction (CBED) allows
quantitative three-dimensional mapping of atomic positions in three-dimensional
materials from a single CBED pattern. In this study we investigate CBED in more
detail by simulating and performing various CBED regimes, with convergent and
divergent wavefronts, on a somewhat simplified system: a 2D monolayer crystal.
In CBED, each CBED spot is in fact an in-line hologram of the sample, where
in-line holography is known to exhibit high intensity contrast in detection of
weak phase objects that are not detectable in conventional in-focus imaging
mode. Adsorbates exhibit strong intensity contrast in zero and higher order
CBED spots, whereas lattice deformation such as strain or rippling cause
noticeable intensity contrast only in the first and higher order CBED spots.
The individual CBED spots can be reconstructed as typical in-line holograms,
and the resolution of 2.13 A can be in principle achieved in the
reconstructions. We provide simulated and experimental examples of CBED of a 2D
monolayer crystal. The simulations show that individual CBED spots can be
treated as in-line holograms and sample distributions such as adsorbates, can
be reconstructed. Individual atoms can be reconstructed from a single CBED
pattern provided the later exhibits high-order CBED spots. Examples of
reconstructions obtained from experimental CBED patterns, at a resolution of
2.7 A, are shown.
| arxiv topic:cond-mat.mtrl-sci cond-mat.mes-hall physics.ins-det |
arxiv_dataset-104191810.10713 | A Remarkably Loud Quasi-Periodicity after a Star is Disrupted by a
Massive Black Hole
astro-ph.HE
The immense tidal forces of massive black holes can rip apart stars that come
too close to them. As the resulting stellar debris spirals inwards, it heats up
and emits x-rays when near the black hole. Here, we report the discovery of an
exceptionally stable 131-second x-ray quasi-periodicity from a black hole after
it disrupted a star. Using a black hole mass indicated from host galaxy scaling
relations implies that, (1) this periodicity originates from very close to the
black hole's event horizon, and (2) the black hole is rapidly spinning. Our
findings suggest that other disruption events with similar highly sensitive
observations likely also exhibit quasi-periodicities that encode information
about the fundamental properties of their black holes.
| arxiv topic:astro-ph.HE |
arxiv_dataset-104201810.10813 | Inverse Problems in Topological Persistence
math.AT cs.CG
In this survey, we review the literature on inverse problems in topological
persistence theory. The first half of the survey is concerned with the question
of surjectivity, i.e. the existence of right inverses, and the second half
focuses on injectivity, i.e. left inverses. Throughout, we highlight the tools
and theorems that underlie these advances, and direct the reader's attention to
open problems, both theoretical and applied.
| arxiv topic:math.AT cs.CG |
arxiv_dataset-104211810.10913 | Distinct orders dividing each other on both sides
math.LO
We construct non-isomorphic linear orders X and Y that are both left-hand and
right-hand divisors of one another, answering positively a question of
Sierpinski.
| arxiv topic:math.LO |
arxiv_dataset-104221810.11013 | Real-space recipes for general topological crystalline states
cond-mat.str-el
Topological crystalline states are short-range entangled states jointly
protected by onsite and crystalline symmetries. While the non-interacting limit
of these states, e.g., the topological crystalline insulators, have been
intensively studied in band theory and have been experimentally discovered, the
classification and diagnosis of their strongly interacting counterparts are
relatively less well understood. Here we present a unified scheme for
constructing all topological crystalline states, bosonic and fermionic, free
and interacting, from real-space "building blocks" and "connectors". Building
blocks are finite-size pieces of lower dimensional topological states protected
by onsite symmetries alone, and connectors are "glue" that complete the open
edges shared by two or multiple pieces of building blocks. The resulted
assemblies are selected against two physical criteria we call the "no-open-edge
condition" and the "bubble equivalence", which, respectively, ensure that each
selected assembly is gapped in the bulk and cannot be deformed to a product
state. The scheme is then applied to obtaining the full classification of
bosonic topological crystalline states protected by several onsite symmetry
groups and each of the 17 wallpaper groups in two dimensions and 230 space
groups in three dimensions. We claim that our real-space recipes give the
complete set of topological crystalline states for bosons and fermions, and
prove the boson case analytically using a spectral sequence expansion of group
cohomology.
| arxiv topic:cond-mat.str-el |
arxiv_dataset-104231810.11113 | The complement of a nIL graph with thirteen vertices is IL
math.CO math.GT
We show that for any simple non-oriented graph G with at least thirteen
vertices either G or its complement is intrinsically linked.
| arxiv topic:math.CO math.GT |
arxiv_dataset-104241810.11213 | Relationships between the Distribution of Watanabe-Strogatz Variables
and Circular Cumulants for Ensembles of Phase Elements
nlin.AO nlin.PS nlin.SI
The Watanabe-Strogatz and Ott-Antonsen theories provided a seminal framework
for rigorous and comprehensive studies of collective phenomena in a broad class
of paradigmatic models for ensembles of coupled oscillators. Recently, a
"circular cumulant" approach was suggested for constructing the perturbation
theory for the Ott-Antonsen approach. In this paper, we derive the relations
between the distribution of Watanabe-Strogatz phases and the circular cumulants
of the original phases. These relations are important for the interpretation of
the circular cumulant approach in the context of the Watanabe-Strogatz and
Ott-Antonsen theories. Special attention is paid to the case of hierarchy of
circular cumulants, which is generally relevant for constructing perturbation
theories for the Watanabe-Strogatz and Ott-Antonsen approaches.
| arxiv topic:nlin.AO nlin.PS nlin.SI |
arxiv_dataset-104251810.11313 | Cosmology in modified $f(R,T)$-gravity
gr-qc
In present paper we propose further modification of $f(R,T)$-gravity (where
$T$ is trace of energy-momentum tensor) by introducing higher derivatives
matter fields. We discuss stability conditions in proposed theory and find
restrictions for parameters to prevent appearance of main type of
instabilities, such as ghost-like and tachyon-like instabilities. We derive
cosmological equations for a few representations of theory and discuss main
differences with convenient $f(R,T)$-gravity without higher derivatives. It is
demonstrated that in presented theory inflationary scenarios appears quite
naturally even in the dust-filled Universe without any additional matter
sources. Finally we construct inflationary model in one of the simplest
representation of the theory, calculate main inflationary parameters and find
that it may be in quite agreement with observations.
| arxiv topic:gr-qc |
arxiv_dataset-104261810.11413 | A Framework for SAR-Optical Stereogrammetry over Urban Areas
eess.IV
Currently, numerous remote sensing satellites provide a huge volume of
diverse earth observation data. As these data show different features regarding
resolution, accuracy, coverage, and spectral imaging ability, fusion techniques
are required to integrate the different properties of each sensor and produce
useful information. For example, synthetic aperture radar (SAR) data can be
fused with optical imagery to produce 3D information using stereogrammetric
methods. The main focus of this study is to investigate the possibility of
applying a stereogrammetry pipeline to very-high-resolution (VHR) SAR-optical
image pairs. For this purpose, the applicability of semi-global matching is
investigated in this unconventional multi-sensor setting. To support the image
matching by reducing the search space and accelerating the identification of
correct, reliable matches, the possibility of establishing an epipolarity
constraint for VHR SAR-optical image pairs is investigated as well. In
addition, it is shown that the absolute geolocation accuracy of VHR optical
imagery with respect to VHR SAR imagery such as provided by TerraSAR-X can be
improved by a multi-sensor block adjustment formulation based on rational
polynomial coefficients. Finally, the feasibility of generating point clouds
with a median accuracy of about 2m is demonstrated and confirms the potential
of 3D reconstruction from SAR-optical image pairs over urban areas.
| arxiv topic:eess.IV |
arxiv_dataset-104271810.11513 | Investigation of re-entrant relaxor behaviour in lead cobalt niobate
ceramic
cond-mat.mtrl-sci
The temperature dependent dielectric properties revealed re-entrant relaxor
behaviour (Tm ~130 K and 210 K for 1 kHz) below a high temperature diffused
phase transition, Tc ~270 K in lead cobalt niobate (PCN). Multiple
positive/negative magnetodielectric effect and deviation from straight line at
~130 K is observed in temperature dependence of inverse susceptibility, which
depicts origin of frustration. Microstructure examination depicts closely
packed grains with grain size ~8-10 microm and XRD pattern revealed single
phase pseudo cubic crystal structure having Pm3m symmetry with lattice constant
~4.0496(2) {\AA}. Rietveld Refinement on XRD data yields larger value of
thermal parameters, implying Pb and O are disordered along <111> and <110>
directions respectively. Observation of A1g (780 cm-1) mode in Raman
spectroscopy and F-spot in SAED pattern along <110> unit axis in TEM suggests
presence of nano scale 1:1 Co and Nb non-stoichiometric chemical ordering
(CORs), akin to lead magnesium niobate (PMN). K-edge XANES spectra reveals the
presence of cobalt in two oxidation states (Co2+ and Co3+); whereas, niobium
exists in Nb3+ state. Therefore, these local-average structural properties
suggest chemical, structural and spatial heterogeneities. Such multiple
heterogeneities are believed to play a crucial role in producing re-entrant
relaxor behaviour.
| arxiv topic:cond-mat.mtrl-sci |
arxiv_dataset-104281810.11613 | Learning and Management for Internet-of-Things: Accounting for
Adaptivity and Scalability
cs.SY cs.DC math.OC
Internet-of-Things (IoT) envisions an intelligent infrastructure of networked
smart devices offering task-specific monitoring and control services. The
unique features of IoT include extreme heterogeneity, massive number of
devices, and unpredictable dynamics partially due to human interaction. These
call for foundational innovations in network design and management. Ideally, it
should allow efficient adaptation to changing environments, and low-cost
implementation scalable to massive number of devices, subject to stringent
latency constraints. To this end, the overarching goal of this paper is to
outline a unified framework for online learning and management policies in IoT
through joint advances in communication, networking, learning, and
optimization. From the network architecture vantage point, the unified
framework leverages a promising fog architecture that enables smart devices to
have proximity access to cloud functionalities at the network edge, along the
cloud-to-things continuum. From the algorithmic perspective, key innovations
target online approaches adaptive to different degrees of nonstationarity in
IoT dynamics, and their scalable model-free implementation under limited
feedback that motivates blind or bandit approaches. The proposed framework
aspires to offer a stepping stone that leads to systematic designs and analysis
of task-specific learning and management schemes for IoT, along with a host of
new research directions to build on.
| arxiv topic:cs.SY cs.DC math.OC |
arxiv_dataset-104291810.11713 | Covariant Equations of Motion of Extended Bodies with Arbitrary Mass and
Spin Multipoles
gr-qc
This paper employs the post-Newtonian approximations of scalar-tensor theory
of gravity along with the Cartesian STF tensors and the Blanchet-Damour
multipole formalism to derive translational and rotational equations of motion
of N extended bodies with arbitrary distribution of mass and velocity. We
assume that spacetime can be covered by a global coordinate chart which is
Minkowskian at infinity. We also introduce N local coordinate charts adapted to
each body and covering a finite domain of space around the body. Gravitational
field of each body is parametrized by an infinite set of the body's mass and
spin multipoles and tidal multipoles of external N-1 bodies. The origin of the
local coordinates is set moving along accelerated worldline of the center of
mass of the body by an appropriate choice of the internal and external dipole
moments of its gravitational field. Translational and rotational equations of
motion are derived by integrating microscopic equations of matter and applying
the method of asymptotic matching. The matching is also used for separating the
post-Newtonian self-field effects from the external gravitational environment
and for constructing the effective background spacetime manifold. It allows us
to present the equations of translational and rotational motion of each body in
covariant form by making use of the Einstein principle of equivalence. Our
approach significantly generalizes the Mathisson-Papapetrou-Dixon covariant
equations of motion with regard to the number of body's multipoles and the
post-Newtonian terms taken into account. The equations of translational and
rotational motion derived in the present paper include the infinite set of mass
and spin multipoles of the bodies and can be used for much more accurate
prediction of orbital dynamics of extended bodies in inspiraling binary systems
before they merge.
| arxiv topic:gr-qc |
arxiv_dataset-104301810.11813 | Direct observation of plasma waves and dynamics induced by
laser-accelerated electron beams
physics.acc-ph
Plasma wakefield acceleration (PWFA) is a novel acceleration technique with
promising prospects for both particle colliders and light sources. However,
PWFA research has so far been limited to a few large-scale accelerator
facilities world-wide. Here, we present first results on plasma wakefield
generation using electron beams accelerated with a 100-TW-class Ti:Sa laser.
Due to their ultrashort duration and high charge density, the laser-accelerated
electron bunches are suitable to drive plasma waves at electron densities in
the order of $10^{19}$ cm$^{-3}$. We capture the beam-induced plasma dynamics
with femtosecond resolution using few-cycle optical probing and, in addition to
the plasma wave itself, we observe a distinctive transverse ion motion in its
trail. This previously unobserved phenomenon can be explained by the
ponderomotive force of the plasma wave acting on the ions, resulting in a
modulation of the plasma density over many picoseconds. Due to the scaling laws
of plasma wakefield generation, results obtained at high plasma density using
high-current laser-accelerated electron beams can be readily scaled to
low-density systems. Laser-driven PWFA experiments can thus act as miniature
models for their larger, conventional counterparts. Furthermore, our results
pave the way towards a novel generation of laser-driven PWFA, which can
potentially provide ultra-low emittance beams within a compact setup.
| arxiv topic:physics.acc-ph |
arxiv_dataset-104311810.11913 | On the resonant reflection of weak, nonlinear sound waves off an entropy
wave
math.AP
We derive a degenerate quasilinear Schr\"odinger equation that describes the
resonant reflection of very weak, nonlinear sound waves off a weak sawtooth
entropy wave.
| arxiv topic:math.AP |
arxiv_dataset-104321810.12013 | Martingale spaces and representations under absolutely continuous
changes of probability
math.PR
In a fully general setting, we study the relation between martingale spaces
under two locally absolutely continuous probabilities and prove that the
martingale representation property (MRP) is always stable under locally
absolutely continuous changes of probability. Our approach relies on minimal
requirements, is constructive and, as shown by a simple example, enables us to
study situations which cannot be covered by the existing theory.
| arxiv topic:math.PR |
arxiv_dataset-104331810.12113 | Dimension-wise Multivariate Orthogonal Polynomials in General
Probability Spaces
math.NA math.PR
This paper puts forward a new generalized polynomial dimensional
decomposition (PDD), referred to as GPDD, comprising hierarchically ordered
measure-consistent multivariate orthogonal polynomials in dependent random
variables. Unlike the existing PDD, which is valid strictly for independent
random variables, no tensor-product structure is assumed or required. Important
mathematical properties of GPDD are studied by constructing dimension-wise
decomposition of polynomial spaces, deriving statistical properties of random
orthogonal polynomials, demonstrating completeness of orthogonal polynomials
for prescribed assumptions, and proving mean-square convergence to the correct
limit, including when there are infinitely many random variables. The GPDD
approximation proposed should be effective in solving high-dimensional
stochastic problems subject to dependent variables.
| arxiv topic:math.NA math.PR |
arxiv_dataset-104341810.12213 | Strictification tensor product of 2-categories
math.CT
Given 2-categories $\mathcal{C}$ and $\mathcal{D}$, let
$\textrm{Lax}(\mathcal{C},\mathcal{D})$ denote the 2-category of lax functors,
lax natural transformations and modifications, and
$[\mathcal{C},\mathcal{D}]_\mathrm{lnt}$ its full sub-2-category of (strict)
2-functors. We give two isomorphic constructions of a 2-category
$\mathcal{C}\boxtimes\mathcal{D}$ satisfying
$\textrm{Lax}(\mathcal{C},\textrm{Lax}(\mathcal{D},\mathcal{E})) \cong
[\mathcal{C}\boxtimes \mathcal{D},\mathcal{E}]_\mathrm{lnt}$, hence
generalising the case of the free distributive law $1\boxtimes 1$. We also
discuss dual constructions.
| arxiv topic:math.CT |
arxiv_dataset-104351810.12313 | $\gamma^\ast \gamma \to \eta, \eta^\prime$ transition form factors
nucl-th hep-ex hep-lat hep-ph nucl-ex
Using a continuum approach to the hadron bound-state problem, we calculate
$\gamma^\ast \gamma \to \eta, \eta^\prime$ transition form factors on the
entire domain of spacelike momenta, for comparison with existing experiments
and in anticipation of new precision data from next-generation $e^+ e^-$
colliders. One novel feature is a model for the contribution to the
Bethe-Salpeter kernel deriving from the non-Abelian anomaly, an element which
is crucial for any computation of $\eta, \eta^\prime$ properties. The study
also delivers predictions for the amplitudes that describe the light- and
strange-quark distributions within the $\eta, \eta^\prime$. Our results compare
favourably with available data. Important to this at large-$Q^2$ is a sound
understanding of QCD evolution, which has a visible impact on the $\eta^\prime$
in particular. Our analysis also provides some insights into the properties of
$\eta, \eta^\prime$ mesons and associated observable manifestations of the
non-Abelian anomaly.
| arxiv topic:nucl-th hep-ex hep-lat hep-ph nucl-ex |
arxiv_dataset-104361810.12413 | Lower bounds for Mahler measure that depend on the number of monomials
math.NT
We prove a new lower bound for the Mahler measure of a polynomial in one and
in several variables that depends on the complex coefficients, and the number
of monomials. In one variable our result generalizes a classical inequality of
Mahler. In $M$ variables our result depends on $\mathbb{Z}^M$ as an ordered
group, and in general our lower bound depends on the choice of ordering.
| arxiv topic:math.NT |
arxiv_dataset-104371810.12513 | Weak-supervision for Deep Representation Learning under Class Imbalance
cs.LG stat.ML
Class imbalance is a pervasive issue among classification models including
deep learning, whose capacity to extract task-specific features is affected in
imbalanced settings. However, the challenges of handling imbalance among a
large number of classes, commonly addressed by deep learning, have not received
a significant amount of attention in previous studies. In this paper, we
propose an extension of the deep over-sampling framework, to exploit
automatically-generated abstract-labels, i.e., a type of side-information used
in weak-label learning, to enhance deep representation learning against class
imbalance. We attempt to exploit the labels to guide the deep representation of
instances towards different subspaces, to induce a soft-separation of inherent
subtasks of the classification problem. Our empirical study shows that the
proposed framework achieves a substantial improvement on image classification
benchmarks with imbalanced among large and small numbers of classes.
| arxiv topic:cs.LG stat.ML |
arxiv_dataset-104381810.12613 | Deep Learning as Feature Encoding for Emotion Recognition
cs.LG stat.ML
Deep learning is popular as an end-to-end framework extracting the prominent
features and performing the classification also. In this paper, we extensively
investigate deep networks as an alternate to feature encoding technique of low
level descriptors for emotion recognition on the benchmark EmoDB dataset.
Fusion performance with such obtained encoded features with other available
features is also investigated. Highest performance to date in the literature is
observed.
| arxiv topic:cs.LG stat.ML |
arxiv_dataset-104391810.12713 | Determining the core radio luminosity function of radio AGNs via copula
astro-ph.GA
The radio luminosity functions (RLFs) of active galactic nuclei (AGNs) are
traditionally measured based on total emission, which doesn't reflect the
current activity of the central black hole. The increasing interest in compact
radio cores of AGNs requires determination of the RLF based on core emission
(i.e., core RLF). In this work we have established a large sample (totaling
1207) of radio-loud AGNs, mainly consisting of radio galaxies (RGs) and
steep-spectrum radio quasars (SSRQs). Based on the sample, we explore the
relationship between core luminosity ($L_c$) and total luminosity ($L_t$) via a
powerful statistical tool called "Copula". The conditional probability
distribution $p(\log L_{c} \mid \log L_{t})$ is obtained. We derive the core
RLF as a convolution of $p(\log L_{c} \mid \log L_{t})$ with the total RLF
which was determined by previous work. We relate the separate RG and SSRQ core
RLFs via a relativistic beaming model and find that SSRQs have an average
Lorentz factor of $\gamma=9.84_{-2.50}^{+3.61}$, and that most are seen within
$8^{\circ} \lesssim \theta \lesssim 45^{\circ}$ of the jet axis. Compared with
the total RLF which is mainly contributed by extended emission, the core RLF
shows a very weak luminosity-dependent evolution, with the number density
peaking around $z\thicksim 0.8$ for all luminosities. Differences between core
and total RLFs can be explained in a framework involving a combination of
density and luminosity evolutions where the cores have significantly weaker
luminosity evolution than the extended emission.
| arxiv topic:astro-ph.GA |
arxiv_dataset-104401810.12813 | Contextual Hourglass Network for Semantic Segmentation of High
Resolution Aerial Imagery
cs.CV cs.AI cs.LG
Semantic segmentation for aerial imagery is a challenging and important
problem in remotely sensed imagery analysis. In recent years, with the success
of deep learning, various convolutional neural network (CNN) based models have
been developed. However, due to the varying sizes of the objects and imbalanced
class labels, it can be challenging to obtain accurate pixel-wise semantic
segmentation results. To address those challenges, we develop a novel semantic
segmentation method and call it Contextual Hourglass Network. In our method, in
order to improve the robustness of the prediction, we design a new contextual
hourglass module which incorporates attention mechanism on processed
low-resolution featuremaps to exploit the contextual semantics. We further
exploit the stacked encoder-decoder structure by connecting multiple contextual
hourglass modules from end to end. This architecture can effectively extract
rich multi-scale features and add more feedback loops for better learning
contextual semantics through intermediate supervision. To demonstrate the
efficacy of our semantic segmentation method, we test it on Potsdam and
Vaihingen datasets. Through the comparisons to other baseline methods, our
method yields the best results on overall performance.
| arxiv topic:cs.CV cs.AI cs.LG |
arxiv_dataset-104411810.12913 | Using convolutional neural networks to predict galaxy metallicity from
three-color images
astro-ph.GA
We train a deep residual convolutional neural network (CNN) to predict the
gas-phase metallicity ($Z$) of galaxies derived from spectroscopic information
($Z \equiv 12 + \log(\rm O/H)$) using only three-band $gri$ images from the
Sloan Digital Sky Survey. When trained and tested on $128 \times 128$-pixel
images, the root mean squared error (RMSE) of $Z_{\rm pred} - Z_{\rm true}$ is
only 0.085 dex, vastly outperforming a trained random forest algorithm on the
same data set (RMSE $=0.130$ dex). The amount of scatter in $Z_{\rm pred} -
Z_{\rm true}$ decreases with increasing image resolution in an intuitive
manner. We are able to use CNN-predicted $Z_{\rm pred}$ and independently
measured stellar masses to recover a mass-metallicity relation with $0.10$ dex
scatter. Because our predicted MZR shows no more scatter than the empirical
MZR, the difference between $Z_{\rm pred}$ and $Z_{\rm true}$ can not be due to
purely random error. This suggests that the CNN has learned a representation of
the gas-phase metallicity, from the optical imaging, beyond what is accessible
with oxygen spectral lines.
| arxiv topic:astro-ph.GA |
arxiv_dataset-104421810.13013 | New analysis of the free energy cost of interfaces in spin glasses
cond-mat.dis-nn cond-mat.mtrl-sci cond-mat.stat-mech
In this work we want to enhance the calculation performed by Franz, Parisi
and Virasoro (FPV) to estimate the free energy cost of interfaces in spin
glasses and evaluate the lower critical dimension at which replica symmetry is
restored. In particular we evaluate the free energy cost for a general class of
effective Hamiltonians showing full replica symmetry breaking, and study the
dependence of this cost on the order parameter and on the temperature. We
confirm the findings of the FPV papers for the scaling of the free energy,
recovering a value for the lower critical dimension of $D_{lc} = 2.5$. In
addition to their results we find a non-trivial dependence of the free energy
density cost on the order parameter and the temperature. Apart from the case of
a restricted class of effective Hamiltonians this dependence cannot be
expressed in terms of functions with a clear physical interpretation, as is the
case in hierarchical models. In addition we connect the results on the lower
critical dimension with recent simulations.
| arxiv topic:cond-mat.dis-nn cond-mat.mtrl-sci cond-mat.stat-mech |
arxiv_dataset-104431810.13113 | Giving Space to Your Message: Assistive Word Segmentation for the
Electronic Typing of Digital Minorities
cs.CL
For readability and disambiguation of the written text, appropriate word
segmentation is recommended for documentation, and it also holds for the
digitized texts. If the language is agglutinative while far from scriptio
continua, for instance in the Korean language, the problem becomes more
significant. However, some device users these days find it challenging to
communicate via key stroking, not only for handicap but also for being
unskilled. In this study, we propose a real-time assistive technology that
utilizes an automatic word segmentation, designed for digital minorities who
are not familiar with electronic typing. We propose a data-driven system
trained upon a spoken Korean language corpus with various non-canonical
expressions and dialects, guaranteeing the comprehension of contextual
information. Through quantitative and qualitative comparison with other text
processing toolkits, we show the reliability of the proposed system and its fit
with colloquial and non-normalized texts, which fulfills the aim of supportive
technology.
| arxiv topic:cs.CL |
arxiv_dataset-104441810.13213 | Arens-Michael envelopes of nilpotent Lie algebras, holomorphic functions
of exponential type, and homological epimorphisms
math.FA
Our aim is to give an explicit description of the Arens-Michael envelope for
the universal enveloping algebra of a finite-dimensional nilpotent complex Lie
algebra. It turns out that the Arens-Michael envelope belongs to a class of
completions introduced by R.~Goodman in 70s. To find a precise form of this
algebra we preliminary characterize the set of holomorphic functions of
exponential type on a simply connected nilpotent complex Lie group. This
approach leads to unexpected connections to Riemannian geometry and the theory
of order and type for entire functions.
As a corollary, it is shown that the Arens-Michael envelope considered above
is a homological epimorphism. So we get a positive answer to a question
investigated earlier by Dosi and Pirkovskii.
| arxiv topic:math.FA |
arxiv_dataset-104451810.13313 | Weakly-Gravitating Objects in dynamical Chern-Simons gravity and
Constraints with Gravity Probe B
gr-qc
Solar system observations have traditionally allowed for very stringent tests
of Einstein's theory of general relativity. We here revisit the possibility of
using these observations to constrain gravitational parity violation as
encapsulated in dynamical Chern-Simons gravity. Working in the small-coupling
and post-Newtonian approximations, we calculate analytically the scalar field
and the gravitomagnetic sector of the gravitational field in the interior and
the exterior of an isolated, weakly-gravitating object with uniform rotation
and a quadrupolar mass deformation. We find that the asymptotic peeling-off
behavior of the exterior fields is consistent with that found for black holes
and neutron stars, as well as for non-relativistic objects, with overall
coefficients that are different and dependent on the structure of the
weak-field source. We then use these fields to explicitly calculate the
dynamical Chern-Simons correction to the spin precession of gyroscopes in orbit
around Earth, which we find to be in the same direction as the Lense-Thirring
effect of General Relativity. We then compare this correction to the spin
precession prediction of General Relativity to the results of the Gravity Probe
B experiment to place a constraint on dynamical Chern-Simons theory that is
consistent with previous approximate estimates. Although we focus primarily on
a single body, our methods can be straightforwardly extended to binary systems
or N-bodies.
| arxiv topic:gr-qc |
arxiv_dataset-104461810.13413 | Mass Splitting in a Linear Sigma Model
hep-lat hep-ph hep-th
We derived the tree level spectrum to an extension to the linear sigma model
describing an EFT for an $SU(3)_c$ gauge theory with $N_f$ flavors of fermions
and $N_1$ fermions have a mass $m_l$ and $N_2$ fermions have a mass $m_h$. We
examined the effects of a small mass splitting on single mass data for 8 and 12
flavors of fermions corresponding to the unperturbed case. Our intention is to
encourage more simulations of split mass theories with 8, 10 and 12 flavors of
fermions.
| arxiv topic:hep-lat hep-ph hep-th |
arxiv_dataset-104471811.00067 | Three-charge superstrata with internal excitations
hep-th
We construct a new family of three-charge $\frac{1}{8}-$BPS smooth solutions
that have the same charges as the supersymmetric D1D5P Black Hole and are
non-invariant under rotations of the compact manifold. We work in type IIB
string theory on $T^4$ and we show how the supergravity and BPS equations
reduce to a linear system, arranged in two `layers' of partial differential
equations. We then build two solutions of our system of equations: the first is
a superdescendant three-charge solution, obtained by acting with rigid
symmetries on a seed two-charge solution, on which we can perform a non-trivial
check for the system of equations; the second is a new superstratum solution
that has both internal and external excitations. We then describe the CFT heavy
states dual to these new geometries.
| arxiv topic:hep-th |
arxiv_dataset-104481811.00167 | Stochastic nonlinear Schroedinger equations in the defocusing mass and
energy critical cases
math.PR
We study the stochastic nonlinear Schroedinger equations with linear
multiplicative noise, particularly in the defocusing mass-critical and
energy-critical cases. For general initial data, we prove the global existence
and uniqueness of solutions in both cases. When the quadratic variation of
noise is globally bounded, we also obtain the rescaled scattering behavior of
solutions in the spaces $L^2$, $H^1$ as well as the pseudo-conformal space.
Moreover, the Stroock-Varadhan type theorem for the topological support of
solutions are also obtained in the Strichartz and local smoothing spaces.
| arxiv topic:math.PR |
arxiv_dataset-104491811.00267 | Precise asymptotics: robust stochastic volatility models
q-fin.PR math.PR
We present a new methodology to analyze large classes of (classical and
rough) stochastic volatility models, with special regard to short-time and
small noise formulae for option prices. Our main tool is the theory of
regularity structures, which we use in the form of [Bayer et al; A regularity
structure for rough volatility, 2017]. In essence, we implement a Laplace
method on the space of models (in the sense of Hairer), which generalizes
classical works of Azencott and Ben Arous on path space and then Aida,
Inahama--Kawabi on rough path space. When applied to rough volatility models,
e.g. in the setting of [Forde-Zhang, Asymptotics for rough stochastic
volatility models, 2017], one obtains precise asymptotic for European options
which refine known large deviation asymptotics.
| arxiv topic:q-fin.PR math.PR |
arxiv_dataset-104501811.00367 | Bi-GANs-ST for Perceptual Image Super-resolution
cs.CV
Image quality measurement is a critical problem for image super-resolution
(SR) algorithms. Usually, they are evaluated by some well-known objective
metrics, e.g., PSNR and SSIM, but these indices cannot provide suitable results
in accordance with the perception of human being. Recently, a more reasonable
perception measurement has been proposed in [1], which is also adopted by the
PIRM-SR 2018 challenge. In this paper, motivated by [1], we aim to generate a
high-quality SR result which balances between the two indices, i.e., the
perception index and root-mean-square error (RMSE). To do so, we design a new
deep SR framework, dubbed Bi-GANs-ST, by integrating two complementary
generative adversarial networks (GAN) branches. One is memory residual SRGAN
(MR-SRGAN), which emphasizes on improving the objective performance, such as
reducing the RMSE. The other is weight perception SRGAN (WP-SRGAN), which
obtains the result that favors better subjective perception via a two-stage
adversarial training mechanism. Then, to produce final result with excellent
perception scores and RMSE, we use soft-thresholding method to merge the
results generated by the two GANs. Our method performs well on the perceptual
image super-resolution task of the PIRM 2018 challenge. Experimental results on
five benchmarks show that our proposal achieves highly competent performance
compared with other state-of-the-art methods.
| arxiv topic:cs.CV |
arxiv_dataset-104511811.00467 | Perturbative Four-Point Functions In Planar N=4 SYM From
Hexagonalization
hep-th
We use hexagonalization to compute four-point correlation functions of long
BPS operators with special R-charge polarizations. We perform the computation
at weak coupling and show that at any loop order our correlators can be
expressed in terms of single-valued polylogarithms with uniform maximal
transcendentality. As a check of our results we extract nine-loop OPE data and
compare it against sum rules of (squared) structures constants of non-protected
exchanged operators described by hundreds of Bethe solutions.
| arxiv topic:hep-th |
arxiv_dataset-104521811.00567 | Radio galaxies - the TeV challenge
astro-ph.HE
Over the past decade, our knowledge of the \gamma-ray sky has been
revolutionized by ground- and space-based observatories by detecting photons up
to several hundreds of tera-electron volt (TeV) energies. A major population of
the $\gamma$-ray bright objects are active galactic nuclei (AGN) with their
relativistic jets pointed along our line-of-sight. Gamma-ray emission is also
detected from nearby mis-aligned AGN such as radio galaxies. While the
TeV-detected radio galaxies (TeVRad) only form a small fraction of the
\gamma-ray detected AGN, their multi-wavelength study offers a unique
opportunity to probe and pinpoint the high-energy emission processes and sites.
Even in the absence of substantial Doppler beaming TeVRad are extremely bright
objects in the TeV sky (luminosities detected up to 10^{45} erg/s), and exhibit
flux variations on timescales shorter than the event-horizon scales (flux
doubling timescale less than 5 minutes). Thanks to the recent advancement in
the imaging capabilities of high-resolution radio interferometry (millimeter
very long baseline interferometry, mm-VLBI), one can probe the scales down to
less than 10 gravitational radii in TeVRad, making it possible not only to test
jet launching models but also to pinpoint the high-energy emission sites and to
unravel the emission mechanisms. This review provides an overview of the
high-energy observations of TeVRad with a focus on the emitting sites and
radiation processes. Some recent approaches in simulations are also sketched.
Observations by the near-future facilities like Cherenkov Telescope Array,
short millimeter-VLBI, and high-energy polarimetry instruments will be crucial
for discriminating the competing high-energy emission models.
| arxiv topic:astro-ph.HE |
arxiv_dataset-104531811.00667 | Treatment Effect Estimation with Noisy Conditioning Variables
econ.EM
I develop a new identification strategy for treatment effects when noisy
measurements of unobserved confounding factors are available. I use proxy
variables to construct a random variable conditional on which treatment
variables become exogenous. The key idea is that, under appropriate conditions,
there exists a one-to-one mapping between the distribution of unobserved
confounding factors and the distribution of proxies. To ensure sufficient
variation in the constructed control variable, I use an additional variable,
termed excluded variable, which satisfies certain exclusion restrictions and
relevance conditions. I establish asymptotic distributional results for
semiparametric and flexible parametric estimators of causal parameters. I
illustrate empirical relevance and usefulness of my results by estimating
causal effects of attending selective college on earnings.
| arxiv topic:econ.EM |
arxiv_dataset-104541811.00767 | The notion of closedness and D-connectedness in Quantale-valued approach
spaces
math.GN math.CT
In this paper, we characterize the local T0 and T1 separation axioms for
quantale-valued gauge space, show how these concepts are related to each other
and apply them to L-approach space and L-approach system. Furthermore, we give
the characterization of a closed point and D-connectedness in quantale-valued
gauge space. Finally, we compare all these concepts with other.
| arxiv topic:math.GN math.CT |
arxiv_dataset-104551811.00867 | Ferromagnetic ordering of linearly coordinated Co ions in
LiSr$_2$[CoN$_2$]
cond-mat.mtrl-sci
LiSr$_2$[CoN$_2$] single crystals were successfully grown out of Li-rich
flux. Temperature- and field-dependent measurements of the magnetization in the
range of $T = 2 - 300$ K and up to $\mu_{0}\textit{H} = 7$ T as well as
measurements of the heat capacity are presented. Ferromagnetic ordering emerges
below $T_C = 44$ K and comparatively large coercivity fields of $\mu_0H = 0.3$
T as well as pronounced anisotropy are observed upon cooling. Polycrystalline
samples of the Ca analog LiCa$_2$[CoN$_2$] were obtained and investigated in a
similar way. In both compounds Co manifests orbital contributions to the
magnetic moment and large single-ion anisotropy that is caused by second-order
Spin-orbit coupling. Quantum chemistry calculations reveal a magnetic
anisotropy energy of 7 meV, twice as large as the values reported for similar
Co $d^{8}$ systems.
| arxiv topic:cond-mat.mtrl-sci |
arxiv_dataset-104561811.00967 | Neural Response Ranking for Social Conversation: A Data-Efficient
Approach
cs.CL
The overall objective of 'social' dialogue systems is to support engaging,
entertaining, and lengthy conversations on a wide variety of topics, including
social chit-chat. Apart from raw dialogue data, user-provided ratings are the
most common signal used to train such systems to produce engaging responses. In
this paper we show that social dialogue systems can be trained effectively from
raw unannotated data. Using a dataset of real conversations collected in the
2017 Alexa Prize challenge, we developed a neural ranker for selecting 'good'
system responses to user utterances, i.e. responses which are likely to lead to
long and engaging conversations. We show that (1) our neural ranker
consistently outperforms several strong baselines when trained to optimise for
user ratings; (2) when trained on larger amounts of data and only using
conversation length as the objective, the ranker performs better than the one
trained using ratings -- ultimately reaching a Precision@1 of 0.87. This
advance will make data collection for social conversational agents simpler and
less expensive in the future.
| arxiv topic:cs.CL |
arxiv_dataset-104571811.01067 | Universal Model for the Turn-on Dynamics of Superconducting Nanowire
Single-Photon Detectors
physics.ins-det physics.optics quant-ph
We describe an electrothermal model for the turn-on dynamics of
superconducting nanowire single-photon detectors (SNSPDs). By extracting a
scaling law from a well-known electrothermal model of SNSPDs, we show that the
rise-time of the readout signal encodes the photon number as well as the length
of the nanowire with scaling $t_\text{rise}\propto \sqrt{\ell/n}$. We show that
these results hold regardless of the exact form of the thermal effects. This
explains how SNSPDs have inherent photon-number resolving capability. We
experimentally verify the photon number dependence by collecting waveforms for
different photon number, rescaling them according to our predicted relation,
and performing statistical analysis that shows that there is no statistical
significance between the rescaled curves. Additionally, we use our predicted
dependence of rise time on detector length to provide further insight to
previous theoretical work by other authors. By assuming a specific thermal
model, we predict that rise time will scale with bias current,
$t_\text{rise}\propto \sqrt{1/I_b}$. We fit this model to experimental data and
find that $t_\text{rise}\propto 1/(n^{0.52 \pm 0.03} ~I_b^{0.63 \pm 0.02})$,
which suggests further work is needed to better understand the bias current
dependence. This work gives new insights into the non-equilibrium dynamics of
thin superconducting films exposed to electromagnetic radiation.
| arxiv topic:physics.ins-det physics.optics quant-ph |
arxiv_dataset-104581811.01167 | Analytic treatment of vortex motion in non-inertial Stokes flows
physics.flu-dyn
We study the steady state motion of incompressible and viscous fluid flow in
a rotating reference frame where vortices may take place. An approximated
analytic solution of the Stokes flow problem is proposed for situations where
the vorticity is highly concentrated along a given direction. The approximation
disconnects the component of velocity along the axis of rotation from the
momentum equation. This enables to find the vorticity from the solution of the
Poisson's equation. We use the Green's function approach to provide solutions
of the three-dimensional flow on cylindrical domains with radial inlet/outlet
velocity profiles by using an exact expansion of the Green's function. This
approximated analytical solution for the vorticity is in good agreement with
numerical solutions computed with the Finite Difference Method (FDM). Keywords:
Analytic approximations, Stokes flow, Green's function, FDM.
| arxiv topic:physics.flu-dyn |
arxiv_dataset-104591811.01267 | Legible Normativity for AI Alignment: The Value of Silly Rules
cs.AI cs.CY cs.HC
It has become commonplace to assert that autonomous agents will have to be
built to follow human rules of behavior--social norms and laws. But human laws
and norms are complex and culturally varied systems, in many cases agents will
have to learn the rules. This requires autonomous agents to have models of how
human rule systems work so that they can make reliable predictions about rules.
In this paper we contribute to the building of such models by analyzing an
overlooked distinction between important rules and what we call silly
rules--rules with no discernible direct impact on welfare. We show that silly
rules render a normative system both more robust and more adaptable in response
to shocks to perceived stability. They make normativity more legible for
humans, and can increase legibility for AI systems as well. For AI systems to
integrate into human normative systems, we suggest, it may be important for
them to have models that include representations of silly rules.
| arxiv topic:cs.AI cs.CY cs.HC |
arxiv_dataset-104601811.01367 | Weak universality of the dynamical $\Phi_3^4$ model on the whole space
math.PR math.AP
We prove the large scale convergence of a class of stochastic weakly
nonlinear reaction-diffusion models on $\mathbb{R}^3$ to the dynamical
$\Phi^4_3$ model by paracontrolled distributions on weighted Besov space. Our
approach depends on the delicate choice of the weight, the localization
operator technique and a modification version of the maximal principle from
[GH18].
| arxiv topic:math.PR math.AP |
arxiv_dataset-104611811.01467 | The one comparing narrative social network extraction techniques
cs.SI physics.soc-ph stat.AP
Analysing narratives through their social networks is an expanding field in
quantitative literary studies. Manually extracting a social network from any
narrative can be time consuming, so automatic extraction methods of varying
complexity have been developed. However, the effect of different extraction
methods on the analysis is unknown. Here we model and compare three extraction
methods for social networks in narratives: manual extraction, co-occurrence
automated extraction and automated extraction using machine learning. Although
the manual extraction method produces more precise results in the network
analysis, it is much more time consuming and the automatic extraction methods
yield comparable conclusions for density, centrality measures and edge weights.
Our results provide evidence that social networks extracted automatically are
reliable for many analyses. We also describe which aspects of analysis are not
reliable with such a social network. We anticipate that our findings will make
it easier to analyse more narratives, which help us improve our understanding
of how stories are written and evolve, and how people interact with each other.
| arxiv topic:cs.SI physics.soc-ph stat.AP |
arxiv_dataset-104621811.01567 | You Only Search Once: Single Shot Neural Architecture Search via Direct
Sparse Optimization
cs.CV cs.LG cs.NE
Recently Neural Architecture Search (NAS) has aroused great interest in both
academia and industry, however it remains challenging because of its huge and
non-continuous search space. Instead of applying evolutionary algorithm or
reinforcement learning as previous works, this paper proposes a Direct Sparse
Optimization NAS (DSO-NAS) method. In DSO-NAS, we provide a novel model pruning
view to NAS problem. In specific, we start from a completely connected block,
and then introduce scaling factors to scale the information flow between
operations. Next, we impose sparse regularizations to prune useless connections
in the architecture. Lastly, we derive an efficient and theoretically sound
optimization method to solve it. Our method enjoys both advantages of
differentiability and efficiency, therefore can be directly applied to large
datasets like ImageNet. Particularly, On CIFAR-10 dataset, DSO-NAS achieves an
average test error 2.84\%, while on the ImageNet dataset DSO-NAS achieves
25.4\% test error under 600M FLOPs with 8 GPUs in 18 hours.
| arxiv topic:cs.CV cs.LG cs.NE |
arxiv_dataset-104631811.01667 | Localization in spin chains with facilitation constraints and disordered
interactions
cond-mat.quant-gas physics.atom-ph
Quantum many-body systems with kinetic constraints exhibit intriguing
relaxation dynamics. Recent experimental progress in the field of cold atomic
gases offers a handle for probing collective behavior of such systems, in
particular for understanding the interplay between constraints and disorder.
Here we explore a spin chain with facilitation constraints --- a feature which
is often used to model classical glass formers --- together with disorder that
originates from spin-spin interactions. The specific model we study, which is
realized in a natural fashion in Rydberg quantum simulators, maps onto an
XX-chain with non-local disorder. Our study shows that the combination of
constraints and seemingly unconventional disorder may lead to interesting
non-equilibrium behaviour in experimentally relevant setups.
| arxiv topic:cond-mat.quant-gas physics.atom-ph |
arxiv_dataset-104641811.01767 | Interpreting Crab Nebula synchrotron spectrum: two acceleration
mechanisms
astro-ph.HE
We outline a model of the Crab Pulsar Wind Nebula with two different
populations of synchrotron emitting particles, arising from two different
acceleration mechanisms: (i) Component-I due to Fermi-I acceleration at the
equatorial portion of the termination shock, with particle spectral index $p_I
\approx 2.2$ above the injection break corresponding to $\gamma_{wind}
\sigma_{wind} \sim 10^5$, peaking in the UV ($\gamma_{wind} \sim 10^2$ is the
bulk Lorentz factor of the wind, $\sigma _{wind} \sim 10^3$ is wind
magnetization); (ii) Component-II due to acceleration at reconnection layers in
the bulk of the turbulent Nebula, with particle index $p_{II} \approx 1.6$. The
model requires relatively slow but highly magnetized wind. For both components
the overall cooling break is in the infra-red at $\sim 0.01$ eV, so that the
Component-I is in the fast cooling regime (cooling frequency below the peak
frequency). In the optical band Component-I produces emission with the cooling
spectral index of $\alpha_o \approx 0.5$, softening towards the edges due to
radiative losses. Above the cooling break, in the optical, UV and X-rays,
Component-I mostly overwhelms Component-II. We hypothesize that acceleration at
large-scale current sheets in the turbulent nebula (Component-II) extends to
the synchrotron burn-off limit of $\epsilon_s \approx 100$ MeV. Thus in our
model acceleration in turbulent reconnection (Component-II) can produce both
hard radio spectra and occasional gamma-ray flares. This model may be
applicable to a broader class of high energy astrophysical objects, like AGNe
and GRB jets, where often radio electrons form a different population from the
high energy electrons.
| arxiv topic:astro-ph.HE |
arxiv_dataset-104651811.01867 | Open-Circuit Voltage Deficit in Cu2ZnSnS4 Solar Cells by Interface Band
Gap Narrowing
cond-mat.mtrl-sci
There is evidence that interface recombination in Cu2ZnSnS4 solar cells
contributes to the open-circuit voltage deficit. Our hybrid density functional
theory calculations suggest that electron-hole recombination at the
Cu2ZnSnS4/CdS interface is caused by a deeper conduction band that slows
electron extraction. In contrast, the bandgap is not narrowed for the
Cu2ZnSnSe4/CdS interface, consistent with a lower open-circuit voltage deficit.
| arxiv topic:cond-mat.mtrl-sci |
arxiv_dataset-104661811.01967 | Enrichment of the hot intracluster medium: observations
astro-ph.HE astro-ph.CO
Four decades ago, the firm detection of an Fe-K emission feature in the X-ray
spectrum of the Perseus cluster revealed the presence of iron in its hot
intracluster medium (ICM). With more advanced missions successfully launched
over the last 20 years, this discovery has been extended to many other metals
and to the hot atmospheres of many other galaxy clusters, groups, and giant
elliptical galaxies, as evidence that the elemental bricks of life -
synthesized by stars and supernovae - are also found at the largest scales of
the Universe. Because the ICM, emitting in X-rays, is in collisional ionisation
equilibrium, its elemental abundances can in principle be accurately measured.
These abundance measurements, in turn, are valuable to constrain the physics
and environmental conditions of the Type Ia and core-collapse supernovae that
exploded and enriched the ICM over the entire cluster volume. On the other
hand, the spatial distribution of metals across the ICM constitutes a
remarkable signature of the chemical history and evolution of clusters, groups,
and ellipticals. Here, we summarise the most significant achievements in
measuring elemental abundances in the ICM, from the very first attempts up to
the era of XMM-Newton, Chandra, and Suzaku and the unprecedented results
obtained by Hitomi. We also discuss the current systematic limitations of these
measurements and how the future missions XRISM and Athena will further improve
our current knowledge of the ICM enrichment.
| arxiv topic:astro-ph.HE astro-ph.CO |
arxiv_dataset-104671811.02067 | Sample Compression, Support Vectors, and Generalization in Deep Learning
cs.LG stat.ML
Even though Deep Neural Networks (DNNs) are widely celebrated for their
practical performance, they possess many intriguing properties related to depth
that are difficult to explain both theoretically and intuitively. Understanding
how weights in deep networks coordinate together across layers to form useful
learners has proven challenging, in part because the repeated composition of
nonlinearities has proved intractable. This paper presents a reparameterization
of DNNs as a linear function of a feature map that is locally independent of
the weights. This feature map transforms depth-dependencies into simple tensor
products and maps each input to a discrete subset of the feature space. Then,
using a max-margin assumption, the paper develops a sample compression
representation of the neural network in terms of the discrete activation state
of neurons induced by s ``support vectors". The paper shows that the number of
support vectors s relates with learning guarantees for neural networks through
sample compression bounds, yielding a sample complexity of O(ns/epsilon) for
networks with n neurons. Finally, the number of support vectors s is found to
monotonically increase with width and label noise but decrease with depth.
| arxiv topic:cs.LG stat.ML |
arxiv_dataset-104681811.02167 | Study of $CP$ Violation in $B^-\rightarrow K^- \pi^+\pi^-$ and
$B^-\rightarrow K^- \sigma(600)$ decays in the QCD factorization approach
hep-ph
In this work, we study the localized $CP$ violation in $B^-\rightarrow
K^-\pi^+\pi^-$ and $B^-\rightarrow K^- \sigma(600)$ decays by employing the
quasi two-body QCD factorization approach. Both the resonance and the
nonresonance contributions are studied for the $B^-\rightarrow K^-\pi^+\pi^-$
decay. The resonance contributions include those not only from $[\pi\pi]$
channels including $\sigma(600)$, $\rho^0(770)$ and $\omega(782)$ but also from
$[K\pi]$ channels including $K^*(892)$, $K_0^*(1430)$, $K^*(1410)$, $K^*(1680)$
and $K_2^*(1430)$. By fitting the experimental data
$\mathcal{A_{CP}}(K^-\pi^+\pi^-)=0.678\pm0.078\pm0.0323\pm0.007$ for
$m_{K^-\pi^+}^2<15$ $\mathrm{GeV}^2$ and $0.08<m_{\pi^+\pi^-}^2<0.66$
$\mathrm{GeV}^2$, we get the end-point divergence parameters in our model,
$\phi_S \in [4.75, 5.95]$ and $\rho_S\in[4.2, 8]$. Using these results for
$\rho_S$ and $\phi_S$, we predict that the $CP$ asymmetry parameter
$\mathcal{A_{CP}} \in [-0.094, -0.034]$ and the branching fraction $\mathcal{B}
\in [1.82, 20.0]\times10^{-5}$ for the $B^-\rightarrow K^-\sigma(600)$ decay.
In addition, we also analyse contributions to the localized $CP$ asymmetry
$\mathcal{A_{CP}}(B^-\rightarrow K^-\pi^+\pi^-)$ from $[\pi\pi]$, $[K\pi]$
channel resonances and nonresonance individually, which are found to be
$\mathcal{A_{CP}}(B^-\rightarrow K^-[\pi^+\pi^-] \rightarrow
K^-\pi^+\pi^-)=0.585\pm0.045$, $\mathcal{A_{CP}}(B^-\rightarrow [K^-\pi^+] \pi
\rightarrow K^-\pi^+\pi^-)=0.086\pm0.021$ and
$\mathcal{A_{CP}}^{NR}(B^-\rightarrow K^-\pi^+\pi^-)=0.061\pm0.0042$,
respectively. Comparing these results, we can see that the localized $CP$
asymmetry in the $B^-\rightarrow K^-\pi^+\pi^-$ decay is mainly induced by the
$[\pi\pi]$ channel resonances while contributions from the $[K\pi]$ channel
resonances and nonresonance are both very small.
| arxiv topic:hep-ph |
arxiv_dataset-104691811.02267 | Time-dependent atomic diffusion in the atmospheres of CP stars. A big
step forward: introducing numerical models including a stellar mass loss
astro-ph.SR
Calculating abundance stratifications in ApBp/HgMn star atmospheres, we are
considering mass-loss in addition to atomic diffusion in our numerical code in
order to achieve more realistic models. These numerical simulations with
mass-loss solve the time dependent continuity equation for plane-parallel
atmospheres; the procedure is iterated until stationary concentrations of the
diffusing elements are obtained throughout a large part of the stellar
atmosphere. We find that Mg stratifications in HgMn star atmospheres are
particularly sensitive to the presence of a mass-loss. For main-sequence stars
with $T_{\rm{eff}}\approx 12000$ K, the observed systematic mild
underabundances of this element can be explained only if a mass-loss rate of
around $4.2\,10^{-14}$ solar mass per year is assumed in our models. Numerical
simulations also reveal that the abundance stratification of P observed in the
HgMn star HD53929 may be understood if a weak horizontal magnetic field of
about 75G is present in this star. However, for a better comparison of our
results with observations, it will be necessary to carry out 3D modelling,
especially when magnetic fields and stellar winds -- which render the
atmosphere anisotropic -- are considered together.
| arxiv topic:astro-ph.SR |
arxiv_dataset-104701811.02367 | Scalable Application- and User-aware Resource Allocation in Enterprise
Networks Using End-host Pacing
cs.NI cs.HC
Scalable user- and application-aware resource allocation for heterogeneous
applications sharing an enterprise network is still an unresolved problem. The
main challenges are: (i) How to define user- and application-aware shares of
resources? (ii) How to determine an allocation of shares of network resources
to applications? (iii) How to allocate the shares per application in
heterogeneous networks at scale? In this paper we propose solutions to the
three challenges and introduce a system design for enterprise deployment.
Defining the necessary resource shares per application is hard, as the intended
use case and user's preferences influence the resource demand. Utility
functions based on user experience enable a mapping of network resources in
terms of throughput and latency budget to a common user-level utility scale. A
multi-objective MILP is formulated to solve the throughput- and delay-aware
embedding of each utility function for a max-min fairness criteria. The
allocation of resources in traditional networks with policing and scheduling
cannot distinguish large numbers of classes. We propose a resource allocation
system design for enterprise networks based on Software-Defined Networking
principles to achieve delay-constrained routing in the network and application
pacing at the end-hosts. The system design is evaluated against best effort
networks with applications competing for the throughput of a constrained link.
The competing applications belong to the five application classes web browsing,
file download, remote terminal work, video streaming, and Voice-over-IP. The
results show that the proposed methodology improves the minimum and total
utility, minimizes packet loss and queuing delay at bottlenecks, establishes
fairness in terms of utility between applications, and achieves predictable
application performance at high link utilization.
| arxiv topic:cs.NI cs.HC |
arxiv_dataset-104711811.02467 | The Self-consistent Matter Coupling of a Class of Minimally Modified
Gravity Theories
gr-qc astro-ph.CO hep-th
The self-consistent matter coupling is found in a broad class of minimally
modified gravity theories which was discovered recently. All constraints in the
theories remain first class and thus a graviton has only 2 local degrees of
freedom. The cosmological solution of one of the examples in this class, the
so-called square root gravity, exhibits a singularity freeness at high energy
limit. At low energy limit, the theory smoothly connects to GR. A general
feature of the theories in this class, with the self-consistent matter coupling
discovered in our current work, is the non-trivial interaction among different
components of matter sector. We have also checked the Hamiltonian structure of
a scalar QED coupling to the square root gravity in the same manner. All
constraints in the theory are first class too and thus the local U(1) gauge
symmetry in scalar QED is preserved.
| arxiv topic:gr-qc astro-ph.CO hep-th |
arxiv_dataset-104721811.02567 | Self-interacting dark matter with a vector mediator: kinetic mixing with
U(1)$_{(B-L)_3}$ gauge boson
hep-ph astro-ph.CO
A spontaneously broken hidden U(1)$_h$ gauge symmetry can explain both the
dark matter stability and the observed relic abundance. In this framework, the
light gauge boson can mediate the strong dark matter self-interaction, which
addresses astrophysical observations that are hard to explain in collisionless
cold dark matter. Motivated by flavoured grand unified theories, we introduce
right-handed neutrinos and a flavoured $B - L$ gauge symmetry for the third
family U(1)$_{(B-L)_3}$. The unwanted relic of the U(1)$_h$ gauge boson decays
into neutrinos via the kinetic mixing with the U(1)$_{(B - L)_3}$ gauge boson.
Indirect detection bounds on dark matter are systematically weakened, since
dark matter annihilation results in neutrinos. However, the kinetic mixing
between U(1)$_{(B - L)_3}$ and U(1)$_Y$ gauge bosons are induced by quantum
corrections and leads to an observable signal in direct and indirect detection
experiments of dark matter. This model can also explain the baryon asymmetry of
the Universe via the thermal leptogenesis. In addition, we discuss the
possibility of explaining the lepton flavour universality violation in
semi-leptonic $B$ meson decays that is recently found in the LHCb experiment.
| arxiv topic:hep-ph astro-ph.CO |
arxiv_dataset-104731811.02667 | Band Selection from Hyperspectral Images Using Attention-based
Convolutional Neural Networks
cs.CV cs.LG stat.ML
This paper introduces new attention-based convolutional neural networks for
selecting bands from hyperspectral images. The proposed approach re-uses
convolutional activations at different depths, identifying the most informative
regions of the spectrum with the help of gating mechanisms. Our attention
techniques are modular and easy to implement, and they can be seamlessly
trained end-to-end using gradient descent. Our rigorous experiments showed that
deep models equipped with the attention mechanism deliver high-quality
classification, and repeatedly identify significant bands in the training data,
permitting the creation of refined and extremely compact sets that retain the
most meaningful features.
| arxiv topic:cs.CV cs.LG stat.ML |
arxiv_dataset-104741811.02767 | Geometry of $CRS$ bi-warped product submanifolds in Sasakian and
cosymplectic manifolds
math.DG
In this paper, we prove that there are no proper $CRS$ bi-warped product
submanifolds other than contact CR-biwarped products in Sasakian manifolds. On
the other hand, we prove that if $M$ is a $CRS$ bi-warped product of the form
$M=N_T \times_{f_1}N^{n_{1}}_\perp\times_{f_2} N^{n_{2}}_\theta$ in a
cosymplectic manifold $\widetilde M$, then its second fundamental form $h$
satisfies the inequality: $$\|h\|^2\geq 2n_1\|\nabla(\ln
f_1)\|^2+2n_2(1+2\cot^2\theta)\|\nabla(\ln f_2)\|^2,$$ where $N_T,\,
N^{n_{1}}_\perp$ and $N^{n_{2}}_\theta$ are invariant, anti-invariant and
proper pointwise slant submanifolds of $\widetilde M$, respectively, and
$\nabla(\ln f_1)$ and $\nabla(\ln f_2)$ denote the gradients of $\ln f_{1}$ and
$\ln f_{2}$, respectively. Several applications of this inequality are given.
At the end, we provide a non-trivial example of bi-warped products satisfying
the equality case.
| arxiv topic:math.DG |
arxiv_dataset-104751811.02867 | Dependence of five and six-loop estimated QCD corrections to the
relation between pole and running masses of heavy quarks on the number of
light flavours
hep-ph hep-ex
In this paper various theoretical approaches are used to define the
dependence of the estimated $\mathcal{O}(\alpha^5_s)$ and
$\mathcal{O}(\alpha^6_s)$-corrections to the QCD relation between pole and
$\rm{\overline{MS}}$ running masses of heavy quarks on the number of light
flavours. It is found that recently studied asymptotic formula for the
coefficients of this relation, based on the infared-renormalon method, does not
reproduce sign-alternating structure in the flavour-dependence of the five and
six-loop corrections, which holds in three other used by us approaches.
| arxiv topic:hep-ph hep-ex |
arxiv_dataset-104761811.02967 | ALMA observations of massive molecular gas reservoirs in dusty
early-type galaxies
astro-ph.GA
Unresolved gas and dust observations show a surprising diversity in the
amount of interstellar matter in early-type galaxies. Using ALMA observations
we resolve the ISM in z$\sim$0.05 early-type galaxies. From a large sample of
early-type galaxies detected in the Herschel Astrophysical Terahertz Large Area
Survey (H-ATLAS) we selected five of the dustiest cases, with dust masses
M$_d\sim$several$\times10^7$M$_\odot$, with the aim of mapping their
submillimetre continuum and $^{12}$CO(2-1) line emission distributions. These
observations reveal molecular gas disks. There is a lack of associated,
extended continuum emission in these ALMA observations, most likely because it
is resolved out or surface brightness limited, if the dust distribution is as
extended as the CO gas. However, two galaxies have central continuum ALMA
detections. An additional, slightly offset, continuum source is revealed in one
case, which may have contributed to confusion in the Herschel fluxes.
Serendipitous continuum detections further away in the ALMA field are found in
another case. Large and massive rotating molecular gas disks are mapped in
three of our targets, reaching a few$\times10^{9}$M$_\odot$. One of these shows
evidence of kinematic deviations from a pure rotating disc. The fields of our
two remaining targets contain only smaller, weak CO sources, slightly offset
from the optical galaxy centres. These may be companion galaxies seen in ALMA
observations, or background objects. These heterogeneous findings in a small
sample of dusty early-type galaxies reveal the need for more such high spatial
resolution studies, to understand statistically how dust and gas are related in
early-type galaxies.
| arxiv topic:astro-ph.GA |
arxiv_dataset-104771811.03067 | On the Three Properties of Stationary Populations and knotting with
Non-Stationary Populations
q-bio.QM q-bio.PE
A population is considered stationary if the growth rate is zero and the age
structure is constant. It thus follows that a population is considered
non-stationary if either its growth rate is non-zero and/or its age structure
is non-constant. We propose three properties that are related to the stationary
population identity (SPI) of population biology by connecting it with
stationary populations and non-stationary populations which are approaching
stationarity. One of these important properties is that SPI can be applied to
partition a population into stationary and non-stationary components. These
properties provide deeper insights into cohort formation in real-world
populations and the length of the duration for which stationary and
non-stationary conditions hold. The new concepts are based on the time gap
between the occurrence of stationary and non-stationary populations within the
SPI framework that we refer to as Oscillatory SPI and the Amplitude of SPI.
This article will appear in Bulletin of Mathematical Biology (Springer)
| arxiv topic:q-bio.QM q-bio.PE |
arxiv_dataset-104781811.03167 | Decision Procedures for Path Feasibility of String-Manipulating Programs
with Complex Operations
cs.FL cs.LO
The design and implementation of decision procedures for checking path
feasibility in string-manipulating programs is an important problem, whose
applications include symbolic execution and automated detection of cross-site
scripting (XSS) vulnerabilities. A (symbolic) path is a finite sequence of
assignments and assertions (i.e. without loops), and checking its feasibility
amounts to determining the existence of inputs that yield a successful
execution.
We give two general semantic conditions which together ensure the
decidability of path feasibility: (1) each assertion admits regular monadic
decomposition, and (2) each assignment uses a (possibly nondeterministic)
function whose inverse relation preserves regularity. We show these conditions
are expressive since they are satisfied by a multitude of string operations.
They also strictly subsume existing decidable string theories, and most
existing benchmarks (e.g. most of Kaluza's, and all of SLOG's, Stranger's, and
SLOTH's). We give a simple decision procedure and an extensible architecture of
a string solver in that a user may easily incorporate his/her own string
functions. We show the general fragment has a tight, but high complexity. To
address this, we propose to allow only partial string functions (i.e., prohibit
nondeterminism) in condition (2). When nondeterministic functions are needed,
we also provide a syntactic fragment that provides a support of
nondeterministic functions but can be reduced to an existing solver SLOTH.
We provide an efficient implementation of our decision procedure for
deterministic partial string functions in a new string solver OSTRICH. It
provides built-in support for concatenation, reverse, functional transducers,
and replaceall and provides a framework for extensibility to support further
string functions. We demonstrate the efficacy of our new solver against other
competitive solvers.
| arxiv topic:cs.FL cs.LO |
arxiv_dataset-104791811.03267 | Stability conditions on threefolds with nef tangent bundles
math.AG
In this paper, we prove the Bogomolov-Gieseker type inequality conjecture for
threefolds with nef tangent bundles. As a corollary, there exist Bridgeland
stability conditions on these threefolds.
| arxiv topic:math.AG |
arxiv_dataset-104801811.03367 | Contact Hamiltonian Systems
math.SG math-ph math.MP
In this paper we study Hamiltonian systems on contact manifolds, which is an
appropriate scenario to discuss dissipative systems. We prove a coisotropic
reduction theorem similar to the one in symplectic mechanics.
| arxiv topic:math.SG math-ph math.MP |
arxiv_dataset-104811811.03467 | A note on the Alster, Menger and D-type properties
math.GN
In this paper we give new characterizations for almost Menger and weakly
Menger spaces by neighborhood assignments and define a natural weakening of
almost D-spaces and weakly D-spaces.
| arxiv topic:math.GN |
arxiv_dataset-104821811.03567 | Biologically-plausible learning algorithms can scale to large datasets
cs.LG cs.AI cs.CV cs.NE stat.ML
The backpropagation (BP) algorithm is often thought to be biologically
implausible in the brain. One of the main reasons is that BP requires symmetric
weight matrices in the feedforward and feedback pathways. To address this
"weight transport problem" (Grossberg, 1987), two more biologically plausible
algorithms, proposed by Liao et al. (2016) and Lillicrap et al. (2016), relax
BP's weight symmetry requirements and demonstrate comparable learning
capabilities to that of BP on small datasets. However, a recent study by
Bartunov et al. (2018) evaluate variants of target-propagation (TP) and
feedback alignment (FA) on MINIST, CIFAR, and ImageNet datasets, and find that
although many of the proposed algorithms perform well on MNIST and CIFAR, they
perform significantly worse than BP on ImageNet. Here, we additionally evaluate
the sign-symmetry algorithm (Liao et al., 2016), which differs from both BP and
FA in that the feedback and feedforward weights share signs but not magnitudes.
We examine the performance of sign-symmetry and feedback alignment on ImageNet
and MS COCO datasets using different network architectures (ResNet-18 and
AlexNet for ImageNet, RetinaNet for MS COCO). Surprisingly, networks trained
with sign-symmetry can attain classification performance approaching that of
BP-trained networks. These results complement the study by Bartunov et al.
(2018), and establish a new benchmark for future biologically plausible
learning algorithms on more difficult datasets and more complex architectures.
| arxiv topic:cs.LG cs.AI cs.CV cs.NE stat.ML |
arxiv_dataset-104831811.03667 | Light Cone Black Holes
gr-qc hep-th
When probed with conformally invariant matter fields, light cones in
Minkowski spacetime satisfy thermodynamical relations which are the analog of
those satisfied by stationary black holes coupled to standard matter fields.
These properties stem from the fact that light cones are conformal Killing
horizons stationary with respect to observers following the radial conformal
Killing fields in flat spacetime. The four laws of light cone thermodynamics
relate notions such as (conformal) temperature, (conformal) surface gravity,
(conformal) energy and a conformally invariant notion related to area change.
These quantities do not admit a direct physical interpretation in flat
spacetime. However, they become the usual thermodynamical quantities when
Minkowski is mapped, via a Weyl transformation, to a target spacetime where the
conformal Killing field becomes a proper Killing field. In this paper we study
the properties of such spacetimes. The simplest realisation turns out to be the
Bertotti-Robinson solution, which is known to encode the near horizon geometry
of near extremal and extremal charged black holes. The analogy between light
cones in flat space and black hole horizons is therefore strengthened. The
construction works in arbitrary dimensions; in two dimensions one recovers the
Jackiv-Teitelboim black hole of dilaton gravity. Other interesting realisations
are also presented.
| arxiv topic:gr-qc hep-th |
arxiv_dataset-104841811.03767 | Energy-Efficient Offloading in Mobile Edge Computing with Edge-Cloud
Collaboration
cs.DC
Multiple access mobile edge computing is an emerging technique to bring
computation resources close to end mobile users. By deploying edge servers at
WiFi access points or cellular base stations, the computation capabilities of
mobile users can be extended. Existing works mostly assume the remote cloud
server can be viewed as a special edge server or the edge servers are willing
to cooperate, which is not practical. In this work, we propose an edge-cloud
cooperative architecture where edge servers can rent for the remote cloud
servers to expedite the computation of tasks from mobile users. With this
architecture, the computation offloading problem is modeled as a mixed integer
programming with delay constraints, which is NP-hard. The objective is to
minimize the total energy consumption of mobile devices. We propose a greedy
algorithm as well as a simulated annealing algorithm to effectively solve the
problem. Extensive simulation results demonstrate that, the proposed greedy
algorithm and simulated annealing algorithm can achieve the near optimal
performance. On average, the proposed greedy algorithm can achieve the same
application completing time budget performance of the Brute Force optional
algorithm with only 31\% extra energy cost. The simulated annealing algorithm
can achieve similar performance with the greedy algorithm.
| arxiv topic:cs.DC |
arxiv_dataset-104851811.03867 | Classification of gravitational-wave glitches via dictionary learning
astro-ph.IM gr-qc
We present a new method for the classification of transient noise signals (or
glitches) in advanced gravitational-wave interferometers. The method uses
learned dictionaries (a supervised machine learning algorithm) for signal
denoising, and untrained dictionaries for the final sparse reconstruction and
classification. We use a data set of 3000 simulated glitches of three different
waveform morphologies, comprising 1000 glitches per morphology. These data are
embedded in non-white Gaussian noise to simulate the background noise of
advanced LIGO in its broadband configuration. Our classification method yields
a 96% accuracy for a large range of initial parameters, showing that learned
dictionaries are an interesting approach for glitch classification. This work
constitutes a preliminary step before assessing the performance of
dictionary-learning methods with actual detector glitches.
| arxiv topic:astro-ph.IM gr-qc |
arxiv_dataset-104861811.03967 | The Gibbs Paradox and the Physical Criteria for the Indistinguishability
of Identical Particles
quant-ph cond-mat.stat-mech
Gibbs paradox in the context of statistical mechanics addresses the issue of
additivity of entropy of mixing gases. The usual discussion attributes the
paradoxical situation to classical distinguishability of identical particles
and credits quantum theory for enabling indistinguishability of identical
particles to solve the problem. We argue that indistinguishability of identical
particles is already a feature in classical mechanics and this is clearly
brought out when the problem is treated in the language of information and
associated entropy. We pinpoint the physical criteria for indistinguishability
that is crucial for the treatment of the Gibbs' problem and the consistency of
its solution with conventional thermodynamics. Quantum mechanics provides a
quantitative criterion, not possible in the classical picture, for the degree
of indistinguishability in terms of visibility of quantum interference, or
overlap of the states as pointed out by von Neumann, thereby endowing the
entropy expression with mathematical continuity and physical reasonableness.
| arxiv topic:quant-ph cond-mat.stat-mech |
arxiv_dataset-104871811.04067 | Benefits of Coded Placement for Networks with Heterogeneous Cache Sizes
cs.IT math.IT
In this work, we study coded placement in caching systems where the users
have unequal cache sizes and demonstrate its performance advantage. In
particular, we propose a caching scheme with coded placement for three-user
systems that outperforms the best caching scheme with uncoded placement. In our
proposed scheme, users cache both uncoded and coded pieces of the files, and
the coded pieces at the users with large memories are decoded using the
unicast/multicast signals intended to serve users with smaller memories.
Furthermore, we extend the proposed scheme to larger systems and show the
reduction in delivery load with coded placement compared to uncoded placement.
| arxiv topic:cs.IT math.IT |
arxiv_dataset-104881811.04167 | Power Normalizing Second-order Similarity Network for Few-shot Learning
cs.CV
Second- and higher-order statistics of data points have played an important
role in advancing the state of the art on several computer vision problems such
as the fine-grained image and scene recognition. However, these statistics need
to be passed via an appropriate pooling scheme to obtain the best performance.
Power Normalizations are non-linear activation units which enjoy
probability-inspired derivations and can be applied in CNNs. In this paper, we
propose a similarity learning network leveraging second-order information and
Power Normalizations. To this end, we propose several formulations capturing
second-order statistics and derive a sigmoid-like Power Normalizing function to
demonstrate its interpretability. Our model is trained end-to-end to learn the
similarity between the support set and query images for the problem of one- and
few-shot learning. The evaluations on Omniglot, miniImagenet and Open MIC
datasets demonstrate that this network obtains state-of-the-art results on
several few-shot learning protocols.
| arxiv topic:cs.CV |
arxiv_dataset-104891811.04267 | Besov class via heat semigroup on Dirichlet spaces I: Sobolev type
inequalities
math.FA math-ph math.AP math.MG math.MP math.PR
We introduce heat semigroup-based Besov classes in the general framework of
Dirichlet spaces. General properties of those classes are studied and
quantitative regularization estimates for the heat semigroup in this scale of
spaces are obtained. As a highlight of the paper, we obtain a far reaching
$L^p$-analogue, $p \ge 1$, of the Sobolev inequality that was proved for $p=2$
by N. Varopoulos under the assumption of ultracontractivity for the heat
semigroup. The case $p=1$ is of special interest since it yields isoperimetric
type inequalities.
| arxiv topic:math.FA math-ph math.AP math.MG math.MP math.PR |
arxiv_dataset-104901811.04367 | Many closed $K$-magnetic geodesics on $\mathbb S^2$
math-ph math.DG math.MP
In this paper we adopt an alternative, analytical approach to Arnol'd problem
\cite{A1} about the existence of closed and embedded $K$-magnetic geodesics in
the round $2$-sphere $\mathbb S^2$, where $K: \mathbb S^2 \rightarrow \mathbb
R$ is a smooth scalar function. In particular, we use Lyapunov-Schmidt
finite-dimensional reduction coupled with a local variational formulation in
order to get some existence and multiplicity results bypassing the use of
symplectic geometric tools such as the celebrated Viterbo's theorem and
Bottkoll results.
| arxiv topic:math-ph math.DG math.MP |
arxiv_dataset-104911811.04467 | Estimating the radiative part of QED effects in systems with
supercritical charge
physics.atom-ph hep-th quant-ph
The effective interaction of the electron magnetic moment anomaly with the
Coulomb field of superheavy nuclei is investigated by taking into account its
dynamical screening at small distances. The shift of the electronic levels,
caused by this interaction, is considered for H-like atoms and for compact
nuclear quasi-molecules, non-perturbatively both in $Z\alpha$ and (partially)
in $\alpha/\pi$. It is shown that the levels shift reveals a non-monotonic
behavior in the region $Z\alpha>1$ and near the threshold of the lower
continuum decreases both with the increasing the charge and with enlarging the
size of the system of Coulomb sources. The last result is generalized to the
total self-energy contribution to the levels shift and so to the possible
behavior of radiative QED effects with virtual photon exchange near the lower
continuum in the supercritical region.
| arxiv topic:physics.atom-ph hep-th quant-ph |
arxiv_dataset-104921811.04567 | Time-changed Poisson processes of order $k$
math.PR
In this article, we study the Poisson process of order k (PPoK) time-changed
with an independent L\'evy subordinator and its inverse, which we call
respectively, as TCPPoK-I and TCPPoK-II, through various distributional
properties, long-range dependence and limit theorems for the PPoK and the
TCPPoK-I. Further, we study the governing difference-differential equations of
the TCPPoK-I for the case inverse Gaussian subordinator. Similarly, we study
the distributional properties, asymptotic moments and the governing
difference-differential equation of TCPPoK-II. As an application to ruin
theory, we give a governing differential equation of ruin probability in
insurance ruin using these processes. Finally, we present some simulated sample
paths of both the processes.
| arxiv topic:math.PR |
arxiv_dataset-104931811.04667 | Review on Multi-Scale Models of Solid-Electrolyte Interphase Formation
physics.chem-ph
Electrolyte reduction products form the solid-electrolyte interphase (SEI) on
negative electrodes of lithium-ion batteries. Even though this process
practically stabilizes the electrode-electrolyte interface, it results in
continued capacity-fade limiting lifetime and safety of lithium-ion batteries.
Recent atomistic and continuum theories give new insights into the growth of
structures and the transport of ions in the SEI. The diffusion of neutral
radicals has emerged as a prominent candidate for the long-term growth
mechanism, because it predicts the observed potential dependence of SEI growth.
| arxiv topic:physics.chem-ph |
arxiv_dataset-104941811.04767 | A Hole torn by QCD Fields
nucl-th
In this paper we determine that a local negative correlation(the Hole) in
$\Delta \eta$ $\Delta \phi$ space of Au + Au collisions at $\sqrt{s_{NN}}$=200
GeV is caused by strong color QCD electric and magnetic fields which are
present in the Glasma Flux Tubes that are generated by the initial conditions.
| arxiv topic:nucl-th |
arxiv_dataset-104951811.04867 | Arguments Related to the Riemann Hypothesis: New Methods and Results
math.NT
Four propositions are considered concerning the relationship between the
zeros of two combinations of the Riemann zeta function and the function itself.
The first is the Riemann hypothesis, while the second relates to the zeros of a
derivative function. It is proved that these are equivalent, and that, if the
Riemann hypothesis holds, then all zeros of the zeta function on the critical
line are simple. The Riemann hypothesis is then shown to imply the third
proposition holds, this being a new necessary condition for the Riemann
hypothesis. The third proposition is shown to be equivalent to the fourth, and
either is shown to yield the result that the distribution of zeros on the
critical line of $\zeta (s)$ is that given by the Riemann hypothesis. The
results given are obtained from a combination of analytic arguments,
experimental mathematical techniques and graphical reasoning.
| arxiv topic:math.NT |
arxiv_dataset-104961811.04967 | The Impact of Timestamp Granularity in Optimistic Concurrency Control
cs.DB
Optimistic concurrency control (OCC) can exploit the strengths of parallel
hardware to provide excellent performance for uncontended transactions, and is
popular in high-performance in-memory databases and transactional systems. But
at high contention levels, OCC is susceptible to frequent aborts, leading to
wasted work and degraded performance. Contention managers, mixed
optimistic/pessimistic concurrency control algorithms, and novel
optimistic-inspired concurrency control algorithms, such as TicToc, aim to
address this problem, but these mechanisms introduce sometimes-high overheads
of their own. We show that in real-world benchmarks, traditional OCC can
outperform these alternative mechanisms by simply adding fine-grained version
timestamps (using different timestamps for disjoint components of each record).
With fine-grained timestamps, OCC gets 1.14x TicToc's throughput in TPC-C at
128 cores (previous work reported TicToc having 1.8x higher throughput than OCC
at 80 hyperthreads). Our study shows that timestamp granularity has a greater
impact than previously thought on the performance of transaction processing
systems, and should not be overlooked in the push for faster concurrency
control schemes.
| arxiv topic:cs.DB |
arxiv_dataset-104971811.05067 | Shall I Compare Thee to a Machine-Written Sonnet? An Approach to
Algorithmic Sonnet Generation
cs.AI cs.CL
We provide an approach for generating beautiful poetry. Our sonnet-generation
algorithm includes several novel elements that improve over the state of the
art, leading to metrical, rhyming poetry with many human-like qualities. These
novel elements include in-line punctuation, part of speech restrictions, and
more appropriate training corpora. Our work is the winner of the 2018 PoetiX
Literary Turing Test Award for computer-generated poetry.
| arxiv topic:cs.AI cs.CL |
arxiv_dataset-104981811.05167 | An abelian analogue of Schanuel's conjecture and applications
math.NT
In this article we study an abelian analogue of Schanuel's conjecture. This
conjecture falls in the realm of the generalised period conjecture of Y.
Andr{\'e}. As shown by C. Bertolin, the generalised period conjecture includes
Schanuel's conjecture as a special case. Extending methods of Bertolin, it can
be shown that the abelian analogue of Schanuel's conjecture we consider, also
follows from Andr{\'e}'s conjecture. C. Cheng et al. showed that the classical
Schanuel's conjecture implies the algebraic independence of the values of the
iterated exponential function and the values of the iterated logarithmic
function, answering a question of M. Waldschmidt. We then investigate a similar
question in the setup of abelian varieties.
| arxiv topic:math.NT |
arxiv_dataset-104991811.05267 | G11.92-0.61 MM 1: A fragmented Keplerian disk surrounding a proto-O star
astro-ph.SR astro-ph.GA
We present high resolution ($\sim$300 au) Atacama Large
Millimeter/submillimeter Array (ALMA) observations of the massive young stellar
object G11.92-0.61 MM 1. We resolve the immediate circumstellar environment of
MM 1 in 1.3 mm continuum emission and CH$_{3}$CN emission for the first time.
The object divides into two main sources - MM 1a, which is the source of a
bipolar molecular outflow, and MM 1b, located 0.57'' (1920 au) to the
South-East. The main component of MM 1a is an elongated continuum structure,
perpendicular to the bipolar outflow, with a size of $0.141'' \times 0.050''$
($480\times170$ au). The gas kinematics toward MM 1a probed via CH$_{3}$CN
trace a variety of scales. The lower energy $J=12-11$ $K=3$ line traces
extended, rotating gas within the outflow cavity, while the $v$8=1 line shows a
clearly-resolved Keplerian rotation signature. Analysis of the gas kinematics
and dust emission shows that the total enclosed mass in MM 1a is $40\pm5$
M$_{\odot}$ (where between 2.2-5.8 M$_{\odot}$ is attributed to the disk),
while MM 1b is $<0.6$ M$_{\odot}$. The extreme mass ratio and orbital
properties of MM 1a and MM 1b suggest that MM 1b is one of the first observed
examples of the formation of a binary star via disk fragmentation around a
massive young (proto)star.
| arxiv topic:astro-ph.SR astro-ph.GA |
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