id stringlengths 16 29 | text stringlengths 86 3.49k | source stringlengths 14 112 |
|---|---|---|
arxiv_dataset-74001606.02093 | Measuring the trilinear neutral Higgs boson couplings in the minimal
supersymmetric standard model at $e^+ e^-$ colliders in the light of the
discovery of a Higgs boson
hep-ph
We consider the measurement of the trilinear couplings of the neutral Higgs
bosons in the Minimal Supersymmetric Standard Model~(MSSM) at a high energy
$e^+ e^-$ linear collider in the light of the discovery of a Higgs boson at the
CERN Large Hadron Collider~(LHC). We identify the state observed at the LHC
with the lightest Higgs boson~($h^0$) of the MSSM, and impose the constraints
following from this identification, as well as other experimental constraints
on the MSSM parameter space. In order to measure trilinear neutral Higgs
couplings, we consider different processes where the heavier Higgs boson
($H^0$) of the MSSM is produced in electron-positron collisions, which
subsequently decays into a pair of lighter Higgs bosons. We identify the
regions of the MSSM parameter space where it may be possible to measure the
trilinear couplings of the Higgs boson at a future electron-positron collider.
A measurement of the trilinear Higgs couplings is a crucial step in the
construction of the Higgs potential, and hence in establishing the phenomena of
spontaneous symmetry breaking in gauge theories.
| arxiv topic:hep-ph |
arxiv_dataset-74011606.02193 | Adapting Sampling Interval of Sensor Networks Using On-Line
Reinforcement Learning
cs.NI cs.LG cs.SY
Monitoring Wireless Sensor Networks (WSNs) are composed of sensor nodes that
report temperature, relative humidity, and other environmental parameters. The
time between two successive measurements is a critical parameter to set during
the WSN configuration because it can impact the WSN's lifetime, the wireless
medium contention and the quality of the reported data. As trends in monitored
parameters can significantly vary between scenarios and within time,
identifying a sampling interval suitable for several cases is also challenging.
In this work, we propose a dynamic sampling rate adaptation scheme based on
reinforcement learning, able to tune sensors' sampling interval on-the-fly,
according to environmental conditions and application requirements. The primary
goal is to set the sampling interval to the best value possible so as to avoid
oversampling and save energy, while not missing environmental changes that can
be relevant for the application. In simulations, our mechanism could reduce up
to 73% the total number of transmissions compared to a fixed strategy and,
simultaneously, keep the average quality of information provided by the WSN.
The inherent flexibility of the reinforcement learning algorithm facilitates
its use in several scenarios, so as to exploit the broad scope of the Internet
of Things.
| arxiv topic:cs.NI cs.LG cs.SY |
arxiv_dataset-74021606.02293 | On the nature of hydrostatic equilibrium in galaxy clusters
astro-ph.CO
In this paper we investigate the level of hydrostatic equilibrium (HE) in the
intra-cluster medium of simulated galaxy clusters, extracted from
state-of-the-art cosmological hydrodynamical simulations performed with the
Smoothed-Particle-Hydrodynamic code GADGET-3. These simulations include several
physical processes, among which stellar and AGN feedback, and have been
performed with an improved version of the code that allows for a better
description of hydrodynamical instabilities and gas mixing processes.
Evaluating the radial balance between the gravitational and hydrodynamical
forces, via the gas accelerations generated, we effectively examine the level
of HE in every object of the sample, its dependence on the radial distance from
the center and on the classification of the cluster in terms of either
cool-coreness or dynamical state. We find an average deviation of 10-20% out to
the virial radius, with no evident distinction between cool-core and
non-cool-core clusters. Instead, we observe a clear separation between regular
and disturbed systems, with a more significant deviation from HE for the
disturbed objects. The investigation of the bias between the hydrostatic
estimate and the total gravitating mass indicates that, on average, this traces
very well the deviation from HE, even though individual cases show a more
complex picture. Typically, in the radial ranges where mass bias and deviation
from HE are substantially different, the gas is characterized by a significant
amount of random motions (>~30 per cent), relative to thermal ones. As a
general result, the HE-deviation and mass bias, at given interesting distance
from the cluster center, are not very sensitive to the temperature
inhomogeneities in the gas.
| arxiv topic:astro-ph.CO |
arxiv_dataset-74031606.02393 | Progressive Attention Networks for Visual Attribute Prediction
cs.CV
We propose a novel attention model that can accurately attends to target
objects of various scales and shapes in images. The model is trained to
gradually suppress irrelevant regions in an input image via a progressive
attentive process over multiple layers of a convolutional neural network. The
attentive process in each layer determines whether to pass or block features at
certain spatial locations for use in the subsequent layers. The proposed
progressive attention mechanism works well especially when combined with hard
attention. We further employ local contexts to incorporate neighborhood
features of each location and estimate a better attention probability map. The
experiments on synthetic and real datasets show that the proposed attention
networks outperform traditional attention methods in visual attribute
prediction tasks.
| arxiv topic:cs.CV |
arxiv_dataset-74041606.02493 | A DSS framework for maintaining relevant features of the Small Business
B2C Websites
cs.CY
Managers are heavily engaged in strategic decision-making for businesses,
particularly in a changing environment. One of the most important decisions for
online small businesses, as part of their strategic planning, is selecting
relevant features on their websites, both to attract and interact with
consumers. However, only a few Australian small businesses use strategic tools
for selecting their website features. As a result, businesses lose potential
domestic sales in the business-to-consumer (B2C) sector. The aim of this study
is to determine the relationship between factors that influence consumers'
online purchasing, and owner/manager strategic decisions in selecting relevant
features for websites. Results from employing qualitative case studies with
small business owner/managers, and a content analysis of website features,
inform the design of a Decision Support Systems (DSS) framework. This may
assist owner/managers' strategic decisions to implement competitive features on
B2C websites that ultimately attract more consumers.
| arxiv topic:cs.CY |
arxiv_dataset-74051606.02593 | Structure Preserving Equivalent Martingale Measures for
$\mathscr{H}$-SII Models
math.PR
In this article we relate the set of structure preserving equivalent
martingale measures $(\mathcal{M})$ for financial models driven by
semimartingales with conditionally independent increments to a set of
measurable and integrable functions $(\mathscr{Y})$. More precisely, we prove
that $(\mathcal{M}\not = \emptyset)$ if, and only if, $(\mathscr{Y}\not =
\emptyset)$, and connect the sets $(\mathcal{M})$ and $(\mathscr{Y})$ to the
semimartingale characteristics of the driving process. As examples we consider
integrated L\'evy models with independent stochastic factors and time-changed
L\'evy models and derive mild conditions for $(\mathcal{M} \not = \emptyset)$.
| arxiv topic:math.PR |
arxiv_dataset-74061606.02693 | Algebraicity and Asymptotics: An explosion of BPS indices from algebraic
generating series
hep-th math.AG
It is an observation of Kontsevich and Soibelman that generating series that
produce certain (generalized) Donaldson Thomas invariants are secretly
algebraic functions over the rationals. From a physical perspective this
observation arises naturally for DT invariants that appear as BPS indices in
theories of class S[A]: explicit algebraic equations (that completely determine
these series) can be derived using (degenerate) spectral networks. In this
paper, we conjecture an algebraic equation associated to DT invariants for the
Kronecker 3-quiver with dimension vectors (3n,2n), n>0 in the non-trivial
region of its stability parameter space. Using a functional equation due to
Reineke, we show algebraicity of generating series for Euler characteristics of
stable moduli for the Kronecker m-quiver assuming algebraicity of generating
series for DT invariants. In the latter part of the paper we deduce very
explicit results on the asymptotics of DT invariants/Euler characteristics
under the assumption of algebraicity of their generating series; explicit large
n asymptotics are deduced for dimension vectors (3n,2n) for the Kronecker
3-quiver. The algebraic equation is derived using spectral network techniques
developed by Gaiotto-Moore-Neitzke, but the main results can be understood
without knowledge of spectral networks.
| arxiv topic:hep-th math.AG |
arxiv_dataset-74071606.02793 | Optimal estimates for the conductivity problem by Green's function
method
math.AP
We study a class of second-order elliptic equations of divergence form, with
discontinuous coefficients and data, which models the conductivity problem in
composite materials. We establish optimal gradient estimates by showing the
explicit dependence of the elliptic coefficients and the distance between
interfacial boundaries of inclusions. The novelty of these estimates is that
they unify the known results in the literature and answer open problem (b)
proposed by Li-Vogelius (2000) for the isotropic conductivity problem. We also
obtain more interesting higher-order derivative estimates, which answers open
problem (c) of Li-Vogelius (2000). It is worth pointing out that the equations
under consideration in this paper are nonhomogeneous.
| arxiv topic:math.AP |
arxiv_dataset-74081606.02893 | Optimal compression for identically prepared qubit states
quant-ph cs.IT math-ph math.IT math.MP
We establish the ultimate limits to the compression of sequences of
identically prepared qubits. The limits are determined by Holevo's information
quantity and are attained through use of the optimal universal cloning machine,
which finds here a novel application to quantum Shannon theory.
| arxiv topic:quant-ph cs.IT math-ph math.IT math.MP |
arxiv_dataset-74091606.02993 | A Wide-Field Survey for Transiting Hot Jupiters and Eclipsing
Pre-Main-Sequence Binaries in Young Stellar Associations
astro-ph.SR astro-ph.EP
The past two decades have seen a significant advancement in the detection,
classification and understanding of exoplanets and binaries. This is due, in
large part, to the increase in use of small-aperture telescopes (< 20 cm) to
survey large areas of the sky to milli-mag precision with rapid cadence. The
vast majority of the planetary and binary systems studied to date consist of
main-sequence or evolved objects, leading to a dearth of knowledge of
properties at early times (< 50 Myr). Only a dozen binaries and one candidate
transiting Hot Jupiter are known among pre-main sequence objects, yet these are
the systems that can provide the best constraints on stellar formation and
planetary migration models. The deficiency in the number of well-characterized
systems is driven by the inherent and aperiodic variability found in
pre-main-sequence objects, which can mask and mimic eclipse signals. Hence, a
dramatic increase in the number of young systems with high-quality observations
is highly desirable to guide further theoretical developments. We have recently
completed a photometric survey of 3 nearby (< 150 pc) and young (< 50 Myr)
moving groups with a small aperture telescope. While our survey reached the
requisite photometric precision, the temporal coverage was insufficient to
detect Hot Jupiters. Nevertheless, we discovered 346 pre-main-sequence binary
candidates, including 74 high-priority objects for further study.
| arxiv topic:astro-ph.SR astro-ph.EP |
arxiv_dataset-74101606.03093 | Turbulence, Transport and Waves in Ohmic Dead Zones
astro-ph.SR
We use local numerical simulations to study a vertically stratified accretion
disk with a resistive mid-plane that damps magnetohydrodynamic (MHD)
turbulence. This is an idealized model for the dead zones that may be present
at some radii in protoplanetary and dwarf novae disks. We vary the relative
thickness of the dead and active zones to quantify how forced fluid motions in
the dead zone change. We find that the residual Reynolds stress near the
mid-plane decreases with increasing dead zone thickness, becoming negligible in
cases where the active to dead mass ratio is less than a few percent. This
implies that purely Ohmic dead zones would be vulnerable to episodic accretion
outbursts via the mechanism of Martin & Lubow (2011). We show that even thick
dead zones support a large amount of kinetic energy, but this energy is largely
in fluid motions that are inefficient at angular momentum transport. Confirming
results from Oishi & Mac Low (2009), the perturbed velocity field in the dead
zone is dominated by an oscillatory, vertically extended circulation pattern
with a low frequency compared to the orbital frequency. This disturbance has
the properties predicted for the lowest order r mode in a hydrodynamic disk. We
suggest that in a global disk similar excitations would lead to propagating
waves, whose properties would vary with the thickness of the dead zone and the
nature of the perturbations (isothermal or adiabatic). Flows with similar
amplitudes would buckle settled particle layers and could reduce the efficiency
of pebble accretion.
| arxiv topic:astro-ph.SR |
arxiv_dataset-74111606.03193 | Stimulated Brillouin scattering in metamaterials
physics.optics
We compute the SBS gain for a metamaterial comprising a cubic lattice of
dielectric spheres suspended in a background dielectric material. Theoretical
methods are presented to calculate the optical, acoustic, and opto-acoustic
parameters that describe the SBS properties of the material at long
wavelengths. Using the electromagnetic and strain energy densities we
accurately characterise the optical and acoustic properties of the
metamaterial. From a combination of energy density methods and perturbation
theory, we recover the appropriate terms of the photoelastic tensor for the
metamaterial. We demonstrate that electrostriction is not necessarily the
dominant mechanism in the enhancement and suppression of the SBS gain
coefficient in a metamaterial, and that other parameters, such as the Brillouin
linewidth, can dominate instead. Examples are presented that exhibit an order
of magnitude enhancement in the SBS gain as well as perfect suppression.
| arxiv topic:physics.optics |
arxiv_dataset-74121606.03293 | Detection of CO and HCN in Pluto's atmosphere with ALMA
astro-ph.EP
Observations of the Pluto-Charon system, acquired with the ALMA
interferometer on June 12-13, 2015, have yielded a detection of the CO(3-2) and
HCN(4-3) rotational transitions from Pluto, providing a strong confirmation of
the presence of CO, and the first observation of HCN, in Pluto's atmosphere.
The CO and HCN lines probe Pluto's atmosphere up to ~450 km and ~900 km
altitude, respectively. The CO detection yields (i) a much improved
determination of the CO mole fraction, as 515+/-40 ppm for a 12 ubar surface
pressure (ii) clear evidence for a well-marked temperature decrease (i.e.,
mesosphere) above the 30-50 km stratopause and a best-determined temperature of
70+/-2 K at 300 km, in agreement with recent inferences from New Horizons /
Alice solar occultation data. The HCN line shape implies a high abundance of
this species in the upper atmosphere, with a mole fraction >1.5x10-5 above 450
km and a value of 4x10-5 near 800 km. The large HCN abundance and the cold
upper atmosphere imply supersaturation of HCN to a degree (7-8 orders of
magnitude) hitherto unseen in planetary atmospheres, probably due to the slow
kinetics of condensation at the low pressure and temperature conditions of
Pluto's upper atmosphere. HCN is also present in the bottom ~100 km of the
atmosphere, with a 10-8 - 10-7 mole fraction; this implies either HCN
saturation or undersaturation there, depending on the precise stratopause
temperature. The HCN column is (1.6+/-0.4)x10^14 cm-2, suggesting a
surface-referred net production rate of ~2x10^7 cm-2s-1. Although HCN
rotational line cooling affects Pluto's atmosphere heat budget, the amounts
determined in this study are insufficient to explain the well-marked mesosphere
and upper atmosphere's ~70 K temperature. We finally report an upper limit on
the HC3N column density (< 2x10^13 cm-2) and on the HC15N / HC14N ratio (<
1/125).
| arxiv topic:astro-ph.EP |
arxiv_dataset-74131606.03393 | Non-perturbative landscape of the Mott-Hubbard transition: Multiple
divergence lines around the critical endpoint
cond-mat.str-el
We analyze the highly non-perturbative regime surrounding the Mott-Hubbard
metal-to-insulator transition (MIT) by means of dynamical mean field theory
calculations at the two-particle level. By extending the results of Sch\"afer,
et al. [Phys. Rev. Lett. 110, 246405 (2013)] we show the existence of
infinitely many lines in the phase diagram of the Hubbard model where the local
Bethe-Salpeter equations, and the related irreducible vertex functions, become
singular in the charge as well as the particle-particle channel. These
divergence lines accumulate around the critical Mott endpoint in accordance
with the interpretation as precursors of the MIT. By comparing our numerical
data with analytical calculations of increasing complexity, such as for the
disordered Binary Mixture and Falicov-Kimball (FK) models, as well as for the
atomic limit (AL) case, (i) we identify two different kinds of divergences
lines; (ii) we classify them in terms of the frequency-structure of the
associated singular eigenvectors; (iii) we investigate their relation to the
multiple branches in the Luttinger-Ward formalism. Moreover, we could
distinguish the situations where the multiple divergences simply reflect the
emergence of an underlying, unique energy scale $\nu^*$ below which
perturbation theory does no longer apply, from those where the breakdown of
perturbation theory affects, not trivially, different energy regimes. Finally,
we discuss the implications of our results on the theoretical understanding of
the non-perturbative physics around the MIT and for future developments of
many-body algorithms applicable in this regime.
| arxiv topic:cond-mat.str-el |
arxiv_dataset-74141606.03493 | Cooperative Data Offload in Opportunistic Networks: From Mobile Devices
to Infrastructure
cs.NI
Opportunistic mobile networks consisting of intermittently connected mobile
devices have been exploited for various applications, such as computational
offloading and mitigating cellular traffic load. In contrast to existing work,
in this paper, we focus on cooperatively offloading data among mobile devices
to maximally improve the probability of data delivery from a mobile device to
intermittently connected infrastructure within a given time constraint, which
is referred to as the \textit{cooperative offloading} problem. Unfortunately,
the estimation of data delivery probability over an opportunistic path is
difficult and cooperative offloading is NP-hard. To this end, we first propose
a probabilistic framework that provides the estimation of such probability.
Based on the proposed probabilistic framework, we design a heuristic algorithm
to solve cooperative offloading at a low computation cost. Due to the lack of
global information, a distributed algorithm is further proposed. The
performance of the proposed approaches is evaluated based on both synthetic
networks and real traces. Experimental results show that the probabilistic
framework can accurately estimate the data delivery probability, cooperative
offloading greatly improves the delivery probability, the heuristic algorithm
approximates the optimum, and the performance of both the heuristic algorithm
and distributed algorithm outperforms other approaches.
| arxiv topic:cs.NI |
arxiv_dataset-74151606.03593 | Amalgamated duplication of the Banach algebra $\bf{\frak A}$ along a
${\frak A}$-bimodule ${\mathcal A}$
math.FA
Let ${\mathcal A}$ and ${\frak A}$ be Banach algebras such that ${\mathcal
A}$ is a Banach ${\frak A}$-bimodule with compatible actions. We define the
product ${\cal A}\rtimes{\frak A}$, which is a strongly splitting Banach
algebra extension of ${\frak A}$ by $\cal A$. After characterization of the
multiplier algebra, topological centre, (maximal) ideals and spectrum of ${\cal
A}\rtimes{\frak A}$, we restrict our investigation to the study of
semisimplicity, regularity, Arens regularity of ${\cal A}\rtimes{\frak A}$ in
relation to that of the algebras $\cal A$, $\frak A$ and the action of $\frak
A$ on $\cal A$. We also compute the first cohomology group $H^1{(}{\cal
A}\rtimes{\frak A},({\cal A}\rtimes{\frak A})^{(n)}{)}$ for all $n\in {\Bbb
N}\cup\{0\}$ as well as the first-order cyclic cohomology group
$H_\lambda^1{(}{\cal A}\rtimes{\frak A},({\cal A}\rtimes{\frak A})^{(1)}{)}$,
where $({\cal A}\rtimes{\frak A})^{(n)}$ is the n-th dual space of ${\cal
A}\rtimes{\frak A}$ when $n\in{\Bbb N}$ and ${\cal A}\rtimes{\frak A}$ itself
when $n=0$. These results are not only of interest in their own right, but also
they pave the way for obtaining some new results for Lau products and module
extensions of Banach algebras as well as triangular Banach algebra. Finally,
special attention is devoted to the cyclic and $n$-weak amenability of ${\cal
A}\rtimes{\frak A}$.
| arxiv topic:math.FA |
arxiv_dataset-74161606.03693 | Phase separation of metastable CoCrFeNi high entropy alloy at
intermediate temperatures
cond-mat.mtrl-sci
The CoCrFeNi alloy is widely accepted as an exemplary stable base for high
entropy alloys (HEAs). Although various investigations prove it to be stable
solid solution, its phase stability is still suspicious. Here, we identified
that the CoCrFeNi HEA was thermally metastable at intermediate temperatures,
and composition decomposition occurred after annealed at 750oC for 800 hrs. The
increased lattice distortion induced by minor addition of Al into the CoCrFeNi
base accelerated the composition decomposition and a second fcc phase with a
different lattice constant occurred in the long time annealed CoCrFeNiAl0.1
HEA. A Cr-rich {\sigma} phase also precipitated from the CoCrFeNiAl0.1 HEA. The
Al element can induce the instability of CoCrFeNi HEA. The revealed metastable
CoCrFeNi at intermediate temperatures will greatly change the way of HEAs
development.
| arxiv topic:cond-mat.mtrl-sci |
arxiv_dataset-74171606.03793 | Singular limits and properties of solutions of some degenerate elliptic
and parabolic equations
math.AP
Let $n\geq 3$, $0\le m<\frac{n-2}{n}$, $\rho_1>0$,
$\beta>\beta_0^{(m)}=\frac{m\rho_1}{n-2-nm}$,
$\alpha_m=\frac{2\beta+\rho_1}{1-m}$ and $\alpha=2\beta+\rho_1$. For any
$\lambda>0$, we prove the uniqueness of radially symmetric solution $v^{(m)}$
of $\La(v^m/m)+\alpha_m v+\beta x\cdot\nabla v=0$, $v>0$, in
$\R^n\setminus\{0\}$ which satisfies $\lim_{|x|\to
0}|x|^{\frac{\alpha_m}{\beta}}v^{(m)}(x)=\lambda^{-\frac{\rho_1}{(1-m)\beta}}$
and obtain higher order estimates of $v^{(m)}$ near the blow-up point $x=0$. We
prove that as $m\to 0^+$, $v^{(m)}$ converges uniformly in $C^2(K)$ for any
compact subset $K$ of $\R^n\setminus\{0\}$ to the solution $v$ of $\La\log
v+\alpha v+\beta x\cdot\nabla v=0$, $v>0$, in $\R^n\bs\{0\}$, which satisfies
$\lim_{|x|\to
0}|x|^{\frac{\alpha}{\beta}}v(x)=\lambda^{-\frac{\rho_1}{\beta}}$. We also
prove that if the solution $u^{(m)}$ of $u_t=\Delta (u^m/m)$, $u>0$, in
$(\R^n\setminus\{0\})\times (0,T)$ which blows up near $\{0\}\times (0,T)$ at
the rate $|x|^{-\frac{\alpha_m}{\beta}}$ satisfies some mild growth condition
on $(\R^n\setminus\{0\})\times (0,T)$, then as $m\to 0^+$, $u^{(m)}$ converges
uniformly in $C^{2+\theta,1+\frac{\theta}{2}}(K)$ for some constant $\theta\in
(0,1)$ and any compact subset $K$ of $(\R^n\setminus\{0\})\times (0,T)$ to the
solution of $u_t=\La\log u$, $u>0$, in $(\R^n\setminus\{0\})\times (0,T)$. As a
consequence of the proof we obtain existence of a unique radially symmetric
solution $v^{(0)}$ of $\La \log v+\alpha v+\beta x\cdot\nabla v=0$, $v>0$, in
$\R^n\setminus\{0\}$, which satisfies $\lim_{|x|\to
0}|x|^{\frac{\alpha}{\beta}}v(x)=\lambda^{-\frac{\rho_1}{\beta}}$.
| arxiv topic:math.AP |
arxiv_dataset-74181606.03893 | Massive Machine-type Communications in 5G: Physical and MAC-layer
solutions
cs.IT cs.NI math.IT
Machine-type communications (MTC) are expected to play an essential role
within future 5G systems. In the FP7 project METIS, MTC has been further
classified into "massive Machine-Type Communication" (mMTC) and "ultra-reliable
Machine-Type Communication" (uMTC). While mMTC is about wireless connectivity
to tens of billions of machine-type terminals, uMTC is about availability, low
latency, and high reliability. The main challenge in mMTC is scalable and
efficient connectivity for a massive number of devices sending very short
packets, which is not done adequately in cellular systems designed for
human-type communications. Furthermore, mMTC solutions need to enable wide area
coverage and deep indoor penetration while having low cost and being energy
efficient. In this article, we introduce the physical (PHY) and medium access
control (MAC) layer solutions developed within METIS to address this challenge.
| arxiv topic:cs.IT cs.NI math.IT |
arxiv_dataset-74191606.03993 | Good subsemigroups of $\mathbb N^n$
math.AC
Value semigroups of non irreducible singular algebraic curves and their
fractional ideals are submonoids of $\mathbb Z^n$ that are closed under
infimums, have a conductor and fulfill a special compatibility property on
their elements. Monoids of $\mathbb N^n$ fulfilling these three conditions are
known in the literature as good semigroups and there are examples of good
semigroups that are not realizable as the value semigroup of an algebraic
curve. In this paper we consider good semigroups independently from their
algebraic counterpart, in a purely combinatoric setting. We define the concept
of good system of generators, and we show that minimal good systems of
generators are unique. Moreover, we give a constructive way to compute the
canonical ideal and the Arf closure of a good subsemigroup when $n=2$.
| arxiv topic:math.AC |
arxiv_dataset-74201606.04093 | Search for resonant production of high-mass photon pairs in
proton-proton collisions at sqrt(s) = 8 and 13 TeV
hep-ex
A search for the resonant production of high-mass photon pairs is presented.
The analysis is based on samples of proton-proton collision data collected by
the CMS experiment at center-of-mass energies of 8 and 13 TeV, corresponding to
integrated luminosities of 19.7 and 3.3 inverse femtobarns, respectively. The
search focuses on spin-0 and spin-2 resonances with masses between 0.5 and 4
TeV and with widths, relative to the mass, between 1.4E-4 and 5.6E-2. Limits
are set on scalar resonances produced through gluon-gluon fusion, and on
Randall-Sundrum gravitons. A modest excess of events compatible with a narrow
resonance with a mass of about 750 GeV is observed. The local significance of
the excess is approximately 3.4 standard deviations. The significance is
reduced to 1.6 standard deviations once the effect of searching under multiple
signal hypotheses is considered. More data are required to determine the origin
of this excess.
| arxiv topic:hep-ex |
arxiv_dataset-74211606.04193 | Small flow-time representation of fermion bilinear operators
hep-lat hep-th
Fermion bilinear operators of mass dimension~$3$, such as the axial-vector
and vector currents, the pseudo-scalar and scalar densities, whose
normalizations are fixed by Ward--Takahashi (WT) relations, are related to
small flow-time behavior of composite operators of fermion fields evolved by
L\"uscher's flow equation. The representations can be useful in lattice
numerical simulations, as recently demonstrated by the WHOT QCD collaboration
for the chiral condensation of the $N_f=2+1$ quantum chromodynamics (QCD) at
finite temperature.
| arxiv topic:hep-lat hep-th |
arxiv_dataset-74221606.04293 | Computability of F{\o}lner sets
math.GR
We define the notion of computability of F{\o}lner sets for finitely
generated amenable groups. We prove, by an explicit description, that the
Kharlampovich group, a finitely presented solvable group with unsolvable word
problem, has computable F{\o}lner sets. We also prove computability of
F{\o}lner sets for a group that is extension of an amenable group with solvable
word problem by a finitely generated group with computable F{\o}lner sets with
subrecursive distortion function. Moreover we obtain some known and some new
upper bounds for the F{\o}lner function in these particular extensions.
| arxiv topic:math.GR |
arxiv_dataset-74231606.04393 | Deep Learning with Darwin: Evolutionary Synthesis of Deep Neural
Networks
cs.CV cs.LG cs.NE stat.ML
Taking inspiration from biological evolution, we explore the idea of "Can
deep neural networks evolve naturally over successive generations into highly
efficient deep neural networks?" by introducing the notion of synthesizing new
highly efficient, yet powerful deep neural networks over successive generations
via an evolutionary process from ancestor deep neural networks. The
architectural traits of ancestor deep neural networks are encoded using
synaptic probability models, which can be viewed as the `DNA' of these
networks. New descendant networks with differing network architectures are
synthesized based on these synaptic probability models from the ancestor
networks and computational environmental factor models, in a random manner to
mimic heredity, natural selection, and random mutation. These offspring
networks are then trained into fully functional networks, like one would train
a newborn, and have more efficient, more diverse network architectures than
their ancestor networks, while achieving powerful modeling capabilities.
Experimental results for the task of visual saliency demonstrated that the
synthesized `evolved' offspring networks can achieve state-of-the-art
performance while having network architectures that are significantly more
efficient (with a staggering $\sim$48-fold decrease in synapses by the fourth
generation) compared to the original ancestor network.
| arxiv topic:cs.CV cs.LG cs.NE stat.ML |
arxiv_dataset-74241606.04493 | Some open problems in mathematical two-dimensional conformal field
theory
math.QA hep-th
We discuss some open problems in a program of constructing and studying
two-dimensional conformal field theories using the representation theory of
vertex operator algebras.
| arxiv topic:math.QA hep-th |
arxiv_dataset-74251606.04593 | Strongvelope Multi-Party Encrypted Messaging Protocol design document
cs.CR
In this document we describe the design of a multi-party messaging encryption
protocol "Strongvelope". We hope that it will prove useful to people interested
in understanding the inner workings of this protocol as well as cryptography
and security experts to review the underlying concepts and assumptions.
In this design paper we are outlining the perspective of chat message
protection through the Strongvelope module. This is different from the product
(the Mega chat) and the transport means which it will be used with. Aspects of
the chat product and transport are only referred to where appropriate, but are
not subject to discussion in this document.
| arxiv topic:cs.CR |
arxiv_dataset-74261606.04693 | Invariance of the White Noise for the Ostrovsky equation
math.AP
In this paper, we construct invariant measures for the Ostrovsky equation
associated with the norm $L^2$. On the other hand, we prove the local well-
posedness in the besov space $\hat{b}^s_{p,\infty}$ for $sp >-1$.
| arxiv topic:math.AP |
arxiv_dataset-74271606.04793 | A splitting method for nonlinear diffusions with nonlocal, nonpotential
drifts
math.AP
We prove an existence result for nonlinear diffusion equations in the
presence of a nonlocal density-dependent drift which is not necessarily
potential. The proof is constructive and based on the Helmholtz decomposition
of the drift and a splitting scheme. The splitting scheme combines transport
steps by the divergence-free part of the drift and semi-implicit minimization
steps \`a la Jordan-Kinderlherer-Otto to deal with the potential part.
| arxiv topic:math.AP |
arxiv_dataset-74281606.04893 | Response of Carbon Nanotube (CNT) Ply Subjected to a Pulsed Magnetic
Field
cond-mat.mtrl-sci
In this study, the possible deformation of a single Carbon Nanotube (CNT) ply
subjected to a pulsed magnetic field was investigated. In all tests the
capacitor bank was charged to 6kJ of energy. A Photon Doppler Velocimetry (PDV)
system was used to measure velocity or displacement of the CNT ply during the
experiments. The resistance of the CNT ply was measured using four-point probe
technique before and after the experiments. Preliminary results show that the
single CNT plies do not permanently deform in response to the pulsed magnetic
fields. However, they can be displaced, either by themselves a small amount
(0.6mm) or by a large amount using a driver material. Also, the resistance of
the CNT plies may increase or decrease depends on the lay-out (i.e., yarn) and
current flow directions.
| arxiv topic:cond-mat.mtrl-sci |
arxiv_dataset-74291606.04993 | Monotone and Convex Stochastic Orders for Processes with Independent
Increments
math.PR
We study monotone and convex stochastic orders for processes with independent
increments. Our contributions are twofold: First, we relate stochastic orders
of the Poisson component to orders of their (generalized) L\'evy measures. The
relation is proven using an interpolation formula for infinitely divisible
laws. Second, we derive explicit conditions on the characteristics of the
processes. In this case, we prove the conditions via constructions of
couplings.
| arxiv topic:math.PR |
arxiv_dataset-74301606.05093 | Solving reaction-diffusion equations on evolving surfaces defined by
biological image data
math.NA
We present a computational approach for solving reaction-diffusion equations
on evolving surfaces which have been obtained from cell image data. It is based
on finite element spaces defined on surface triangulations extracted from time
series of 3D images. A model for the transport of material between the
subsequent surfaces is required where we postulate a velocity in normal
direction. We apply the technique to image data obtained from a spreading
neutrophil cell. By simulating FRAP experiments we investigate the impact of
the evolving geometry on the recovery. We find that for idealised FRAP
conditions, changes in membrane geometry, easily account for differences of
$\times 10$ in recovery half-times, which shows that experimentalists must take
great care when interpreting membrane photobleaching results. We also
numerically solve an activator -- depleted substrate system and report on the
effect of the membrane movement on the pattern evolution.
| arxiv topic:math.NA |
arxiv_dataset-74311606.05193 | Detailed study of the microwave emission of the supernova remnant 3C 396
astro-ph.SR astro-ph.GA
We have observed the supernova remnant 3C~396 in the microwave region using
the Parkes 64-m telescope. Observations have been made at 8.4 GHz, 13.5 GHz,
and 18.6 GHz and in polarisation at 21.5 GHz. We have used data from several
other observatories, including previously unpublished observations performed by
the Green Bank Telescope at 31.2 GHz, to investigate the nature of the
microwave emission of 3C 396. Results show a spectral energy distribution
dominated by a single component power law emission with $\alpha=(-0.364 \pm
0.017)$. Data do not favour the presence of anomalous microwave emission coming
from the source. Polarised emission at 21.5 GHz is consistent with
synchrotron-dominated emission. We present microwave maps and correlate them
with infrared (IR) maps in order to characterise the interplay between thermal
dust and microwave emission. IR vs. microwave TT plots reveal poor correlation
between mid-infrared and microwave emission from the core of the source. On the
other hand, a correlation is detected in the tail emission of the outer shell
of 3C 396, which could be ascribed to Galactic contamination.
| arxiv topic:astro-ph.SR astro-ph.GA |
arxiv_dataset-74321606.05293 | A Comparison of Big Data Frameworks on a Layered Dataflow Model
cs.DC
In the world of Big Data analytics, there is a series of tools aiming at
simplifying programming applications to be executed on clusters. Although each
tool claims to provide better programming, data and execution models, for which
only informal (and often confusing) semantics is generally provided, all share
a common underlying model, namely, the Dataflow model. The Dataflow model we
propose shows how various tools share the same expressiveness at different
levels of abstraction. The contribution of this work is twofold: first, we show
that the proposed model is (at least) as general as existing batch and
streaming frameworks (e.g., Spark, Flink, Storm), thus making it easier to
understand high-level data-processing applications written in such frameworks.
Second, we provide a layered model that can represent tools and applications
following the Dataflow paradigm and we show how the analyzed tools fit in each
level.
| arxiv topic:cs.DC |
arxiv_dataset-74331606.05393 | Atomically-thin Ohmic Edge Contacts Between Two-dimensional Materials
cond-mat.mes-hall cond-mat.mtrl-sci
With the decrease of the dimensions of electronic devices, the role played by
electrical contacts is ever increasing, eventually coming to dominate the
overall device volume and total resistance. This is especially problematic for
monolayers of semiconducting transition metal dichalcogenides (TMDs), which are
promising candidates for atomically thin electronics. Ideal electrical contacts
to them would require the use of similarly thin electrode materials while
maintaining low contact resistances. Here we report a scalable method to
fabricate ohmic graphene edge contacts to two representative monolayer TMDs -
MoS2 and WS2. The graphene and TMD layer are laterally connected with
wafer-scale homogeneity, no observable overlap or gap, and a low average
contact resistance of 30 k$\Omega$ $\mu$m. The resulting graphene edge contacts
show linear current-voltage (IV) characteristics at room temperature, with
ohmic behavior maintained down to liquid helium temperatures.
| arxiv topic:cond-mat.mes-hall cond-mat.mtrl-sci |
arxiv_dataset-74341606.05493 | Special solitons on 3-manifolds
math.DG
In this paper, we study solitons on $3$-dimensional manifolds. In particular,
we show that $3$-dimensional pseudo-symmetric gradient Ricci solitons and
nontrivial gradient Yamabe solitons are locally isometric to either
$\mathbb{R}^{3}$, $\mathbb{S}^{3}$, $\mathbb{H}^{3}$, $\mathbb{R} \times
\mathbb{S}^{2}$ or $\mathbb{R} \times \mathbb{H}^{2}$.
| arxiv topic:math.DG |
arxiv_dataset-74351606.05593 | Introspective Agents: Confidence Measures for General Value Functions
cs.AI
Agents of general intelligence deployed in real-world scenarios must adapt to
ever-changing environmental conditions. While such adaptive agents may leverage
engineered knowledge, they will require the capacity to construct and evaluate
knowledge themselves from their own experience in a bottom-up, constructivist
fashion. This position paper builds on the idea of encoding knowledge as
temporally extended predictions through the use of general value functions.
Prior work has focused on learning predictions about externally derived signals
about a task or environment (e.g. battery level, joint position). Here we
advocate that the agent should also predict internally generated signals
regarding its own learning process - for example, an agent's confidence in its
learned predictions. Finally, we suggest how such information would be
beneficial in creating an introspective agent that is able to learn to make
good decisions in a complex, changing world.
| arxiv topic:cs.AI |
arxiv_dataset-74361606.05693 | Structured Stochastic Linear Bandits
stat.ML cs.LG
The stochastic linear bandit problem proceeds in rounds where at each round
the algorithm selects a vector from a decision set after which it receives a
noisy linear loss parameterized by an unknown vector. The goal in such a
problem is to minimize the (pseudo) regret which is the difference between the
total expected loss of the algorithm and the total expected loss of the best
fixed vector in hindsight. In this paper, we consider settings where the
unknown parameter has structure, e.g., sparse, group sparse, low-rank, which
can be captured by a norm, e.g., $L_1$, $L_{(1,2)}$, nuclear norm. We focus on
constructing confidence ellipsoids which contain the unknown parameter across
all rounds with high-probability. We show the radius of such ellipsoids depend
on the Gaussian width of sets associated with the norm capturing the structure.
Such characterization leads to tighter confidence ellipsoids and, therefore,
sharper regret bounds compared to bounds in the existing literature which are
based on the ambient dimensionality.
| arxiv topic:stat.ML cs.LG |
arxiv_dataset-74371606.05793 | Canonical transfer and multiscale energetics for primitive and
quasi-geostrophic atmospheres
physics.ao-ph
The past years have seen the success of a novel multiscale energetic
formalism in a variety of ocean and engineering fluid applications. In a
self-contained way, this study introduces it to the atmospheric dynamical
diagnostics, with important theoretical updates. Multiscale energy equations
are derived using a new analysis apparatus, namely, multiscale window
transform, with respect to both the primitive equation and quasi-geostrophic
models. A reconstruction of the "atomic" energy fluxes on the multiple scale
windows allows for a natural and unique separation of the in-scale transports
and cross-scale transfers from the intertwined nonlinear processes. The
resulting energy transfers bear a Lie bracket form, reminiscent of the Poisson
bracket in Hamiltonian mechanics, we hence would call them "canonical". A
canonical transfer process is a mere redistribution of energy among scale
windows, without generating or destroying energy as a whole. By classification,
a multiscale energetic cycle comprises of available potential energy (APE)
transport, kinetic energy (KE) transport, pressure work, buoyancy conversion,
work done by external forcing and friction, and the cross-scale canonical
transfers of APE and KE which correspond respectively to the baroclinic and
barotropic instabilities, among others, in geophysical fluid dynamics. A
buoyancy conversion takes place in an individual window only, bridging the two
types of energy namely KE and APE, it does not involve any processes among
different scale windows, and is hence basically not related to instabilities.
This formalism is exemplified with a preliminary application to the
Madden-Julian Oscillation (MJO) study.
| arxiv topic:physics.ao-ph |
arxiv_dataset-74381606.05893 | You are Who You Know and How You Behave: Attribute Inference Attacks via
Users' Social Friends and Behaviors
cs.SI physics.soc-ph
We propose new privacy attacks to infer attributes (e.g., locations,
occupations, and interests) of online social network users. Our attacks
leverage seemingly innocent user information that is publicly available in
online social networks to infer missing attributes of targeted users. Given the
increasing availability of (seemingly innocent) user information online, our
results have serious implications for Internet privacy -- private attributes
can be inferred from users' publicly available data unless we take steps to
protect users from such inference attacks.
To infer attributes of a targeted user, existing inference attacks leverage
either the user's publicly available social friends or the user's behavioral
records (e.g., the webpages that the user has liked on Facebook, the apps that
the user has reviewed on Google Play), but not both. As we will show, such
inference attacks achieve limited success rates. However, the problem becomes
qualitatively different if we consider both social friends and behavioral
records. To address this challenge, we develop a novel model to integrate
social friends and behavioral records and design new attacks based on our
model. We theoretically and experimentally demonstrate the effectiveness of our
attacks. For instance, we observe that, in a real-world large-scale dataset
with 1.1 million users, our attack can correctly infer the cities a user lived
in for 57% of the users, via confidence estimation, we are able to increase the
attack success rate to over 90% if the attacker selectively attacks a half of
the users. Moreover, we show that our attack can correctly infer attributes for
significantly more users than previous attacks.
| arxiv topic:cs.SI physics.soc-ph |
arxiv_dataset-74391606.05993 | On some study of the Fine Spectra of $n$-th band triangular matrices
math.SP
It has been observed that for the 2nd and 3rd band lower triangular matrices
$B(r,s)$ and $B(r,s,t)$, only the boundary of the spectrum gives the continuous
spectrum while the rest of the entire interior region gives the residual
spectrum over the sequence spaces $c_0$, $l_p$ and $bv_p$. The main focus of
our present study is to investigate the possibilities of the occurrence of the
similar kinds of behavior for the cases of $n (\ge4)$ band lower triangular
matrices over the sequence spaces $c_0$, $l_p$ and $bv_p$. The outcomes depicts
that not only the boundary part but a finite set from the interior region of
the spectrum is included in the continuous spectrum while the same set is
excluded from the residual spectrum. In this context, we have proved an
interesting result regarding the image of the closed unit disk $|z|\le 1$ under
a polynomial of degree $n\ge 1$ which plays the key role in our study. Similar
studies has also been done for the sequence spaces $c$, $l_1$, $bv$ and
$l_\infty$. Upper triangular matrices has also been investigated for some
sequence spaces.
| arxiv topic:math.SP |
arxiv_dataset-74401606.06093 | Edge Majoranas on locally flat surfaces - the cone and the M\"obius band
cond-mat.str-el
In this paper, we investigate the edge Majorana modes in the simplest
possible $p{}_{x}+ip_{y}$ superconductor defined on surfaces with different
geometry - the annulus, the cylinder, the M\"obius band and a cone (by cone we
mean a cone with the tip cut away so it is topologically equivalent to the
annulus and cylinder)- and with different configuration of magnetic fluxes
threading holes in these surfaces. In particular, we shall address two
questions: Given that, in the absence of any flux, the ground state on the
annulus does not support Majorana modes, while the one on the cylinder does,
how is it possible that the conical geometry can interpolate smoothly between
the two? Given that in finite geometries edge Majorana modes have to come in
pairs, how can a $p{}_{x}+ip_{y}$ state be defined on a M\"obius band, which
has only one edge? We show that the key to answering these questions is that
the ground state depends on the geometry, even though all the surfaces are
locally flat. In the case of the truncated cone, there is a non-trivial
holonomy, while the non-orientable M\"obius band must necessarily support a
domain wall.
| arxiv topic:cond-mat.str-el |
arxiv_dataset-74411606.06193 | Single quark entropy and the Polyakov loop
hep-lat
We study Quantum Chromodynamics (QCD) with 2+1 flavors with almost physical
quark masses using the highly improved staggered quark action (HISQ). We
calculate the Polyakov loop in a wide temperature range, obtain the free energy
and the entropy of a single static quark and discuss the QCD crossover region
in detail. We show that the entropy has a peak close to the chiral crossover
and consider the consequences for the deconfinement aspects of the crossover
phenomena. We study the renormalized Polyakov loop susceptibilities and place
them into the context of the crossover. We also obtain a quantitative result
for the onset of weak coupling behavior at high temperatures.
| arxiv topic:hep-lat |
arxiv_dataset-74421606.06293 | Precise limits on cosmological variability of the fine-structure
constant with zinc and chromium quasar absorption lines
astro-ph.CO gr-qc hep-ph hep-th physics.atom-ph
The strongest transitions of Zn and CrII are the most sensitive to relative
variations in the fine-structure constant ($\Delta\alpha/\alpha$) among the
transitions commonly observed in quasar absorption spectra. They also lie
within just 40\AA\ of each other (rest frame), so they are resistant to the
main systematic error affecting most previous measurements of
$\Delta\alpha/\alpha$: long-range distortions of the wavelength calibration.
While Zn and CrII absorption is normally very weak in quasar spectra, we
obtained high signal-to-noise, high-resolution echelle spectra from the Keck
and Very Large Telescopes of 9 rare systems where it is strong enough to
constrain $\Delta\alpha/\alpha$ from these species alone. These provide 12
independent measurements (3 quasars were observed with both telescopes) at
redshifts 1.0--2.4, 11 of which pass stringent reliability criteria. These 11
are all consistent with $\Delta\alpha/\alpha=0$ within their individual
uncertainties of 3.5--13 parts per million (ppm), with a weighted mean
$\Delta\alpha/\alpha = 1.2\pm1.7_{\rm stat}\pm0.9_{\rm sys}$ ppm (1$\sigma$
statistical and systematic uncertainties), indicating no significant
cosmological variations in $\alpha$. This is the first statistical sample of
absorbers that is resistant to long-range calibration distortions (at the $<$1
ppm level), with a precision comparable to previous large samples of $\sim$150
(distortion-affected) absorbers. Our systematic error budget is instead
dominated by much shorter-range distortions repeated across echelle orders of
individual spectra.
| arxiv topic:astro-ph.CO gr-qc hep-ph hep-th physics.atom-ph |
arxiv_dataset-74431606.06393 | A Generalized Uhlenbeck and Beth Formula for the Third Cluster
Coefficient
physics.chem-ph
Relatively recently (A. Amaya-Tapia, S. Y. Larsen and M. Lassaut. Ann. Phys.,
vol. 306 (2011) 406), we presented a formula for the evaluation of the third
Bose fugacity coefficient - leading to the third virial coefficient - in terms
of three-body eigenphase shifts, for particles subject to repulsive forces. An
analytical calculation for a 1-dim. model, for which the result is known,
confirmed the validity of this approach. We now extend the formalism to
particles with attractive forces, and therefore must allow for the possibility
that the particles have bound states. We thus obtain a true generalization of
the famous formula of Uhlenbeck and Beth (G.E. Uhlenbeck and E. Beth. Physica,
vol. 3 (1936) 729; E. Beth and G.E. Uhlenbeck. ibid, vol.4 (1937) 915) (and of
Gropper (L. Gropper. Phys. Rev. vol. 50 (1936) 963; ibid vol. 51 (1937) 1108))
for the second virial. We illustrate our formalism by a calculation, in an
adiabatic approximation, of the third cluster in one dimension, using McGuire's
model as in our previous paper, but with attractive forces. The inclusion of
three-body bound states is trivial; taking into account states having
asymptotically two particles bound, and one free, is not.
| arxiv topic:physics.chem-ph |
arxiv_dataset-74441606.06493 | Tukey Order, Calibres and the Rationals
math.GN
One partially ordered set, $Q$, is a Tukey quotient of another, $P$, denoted
$P \geq_T Q$, if there is a map $\phi : P \to Q$ carrying cofinal sets of $P$
to cofinal sets of $Q$. Let $X$ be a space and denote by $\mathcal{K}(X)$ the
set of compact subsets of $X$, ordered by inclusion. For certain separable
metrizable spaces $M$, Tukey upper and lower bounds of $\mathcal{K}(M)$ are
calculated. Results on invariants of $\mathcal{K}(M)$'s are deduced. The
structure of all $\mathcal{K}(M)$'s under $\le_T$ is investigated. Particular
emphasis is placed on the position of $\mathcal{K}(M)$ when $M$ is: completely
metrizable, the rationals $\mathbb{Q}$, co-analytic or analytic.
| arxiv topic:math.GN |
arxiv_dataset-74451606.06593 | A Distributed Newton Method for Large Scale Consensus Optimization
cs.DC math.OC
In this paper, we propose a distributed Newton method for consensus
optimization. Our approach outperforms state-of-the-art methods, including
ADMM. The key idea is to exploit the sparsity of the dual Hessian and recast
the computation of the Newton step as one of efficiently solving symmetric
diagonally dominant linear equations. We validate our algorithm both
theoretically and empirically. On the theory side, we demonstrate that our
algorithm exhibits superlinear convergence within a neighborhood of optimality.
Empirically, we show the superiority of this new method on a variety of machine
learning problems. The proposed approach is scalable to very large problems and
has a low communication overhead.
| arxiv topic:cs.DC math.OC |
arxiv_dataset-74461606.06693 | Incorporating doubly resonant $W^\pm$ data in a global fit of SMEFT
parameters to lift flat directions
hep-ph
We calculate the double pole contribution to two to four fermion scattering
through $W^{\pm}$ currents at tree level in the Standard Model Effective Field
Theory (SMEFT). We assume all fermions to be massless, $\rm U(3)^5$ flavour and
$\rm CP$ symmetry. Using this result, we update the global constraint picture
on SMEFT parameters including LEPII data on these charged current processes,
and also include modifications to our fit procedure motivated by a companion
paper focused on $W^{\pm}$ mass extractions. The fit reported is now to 177
observables and emphasises the need for a consistent inclusion of theoretical
errors, and a consistent treatment of observables. Including charged current
data lifts the two-fold degeneracy previously encountered in LEP (and lower
energy) data, and allows us to set simultaneous constraints on 20 of 53 Wilson
coefficients in the SMEFT, consistent with our assumptions. This allows the
model independent inclusion of LEP data in SMEFT studies at LHC, which are
projected into the SMEFT in a consistent fashion. We show how stronger
constraints can be obtained by using some combinations of Wilson coefficients,
when making assumptions on the UV completion of the Standard Model, or in an
inconsistent analysis. We explain why strong bounds at the per-mille or
sub-per-mille level on some combinations of Wilson coefficients in the
Effective Lagrangian can be artificially enhanced in fits of this form in
detail. This explains some of the different claims present in the literature.
| arxiv topic:hep-ph |
arxiv_dataset-74471606.06793 | Scalable Semi-supervised Learning with Graph-based Kernel Machine
cs.LG
Acquiring labels are often costly, whereas unlabeled data are usually easy to
obtain in modern machine learning applications. Semi-supervised learning
provides a principled machine learning framework to address such situations,
and has been applied successfully in many real-word applications and
industries. Nonetheless, most of existing semi-supervised learning methods
encounter two serious limitations when applied to modern and large-scale
datasets: computational burden and memory usage demand. To this end, we present
in this paper the Graph-based semi-supervised Kernel Machine (GKM), a method
that leverages the generalization ability of kernel-based method with the
geometrical and distributive information formulated through a spectral graph
induced from data for semi-supervised learning purpose. Our proposed GKM can be
solved directly in the primal form using the Stochastic Gradient Descent method
with the ideal convergence rate $O(\frac{1}{T})$. Besides, our formulation is
suitable for a wide spectrum of important loss functions in the literature of
machine learning (e.g., Hinge, smooth Hinge, Logistic, L1, and
{\epsilon}-insensitive) and smoothness functions (i.e., $l_p(t) = |t|^p$ with
$p\ge1$). We further show that the well-known Laplacian Support Vector Machine
is a special case of our formulation. We validate our proposed method on
several benchmark datasets to demonstrate that GKM is appropriate for the
large-scale datasets since it is optimal in memory usage and yields superior
classification accuracy whilst simultaneously achieving a significant
computation speed-up in comparison with the state-of-the-art baselines.
| arxiv topic:cs.LG |
arxiv_dataset-74481606.06893 | The "$a_1(1420)$" peak as the $\pi f_0(980)$ decay mode of the
$a_1(1260)$
hep-ph
We study the decay mode of the $a_1(1260)$ into a $\pi^+$ in p-wave and the
$f_0(980)$ that decays into $\pi^+ \pi^-$ in s-wave. The mechanisms proceeds
via a triangular mechanism where the $a_1(1260)$ decays into $K^* \bar K$, the
$K^*$ decays to an external $\pi^+$ and an internal $K$ that fuses with the
$\bar K$ to produce the $f_0(980)$ resonance. The mechanism develops a
singularity at a mass of the $a_1(1260)$ around 1420 MeV, producing a peak in
the cross section of the $\pi p$ reaction, used to generate the mesonic final
state, which provides a natural explanation of all the features observed in the
COMPASS experiment, where a peak observed at this energy is tentatively
associated to a new resonance called $a_1(1420)$. On the other hand, the
triangular singularity studied here gives rise to a remarkable feature, where a
peak is seen for a certain decay channel of a resonance at an energy about 200
MeV higher than its nominal mass.
| arxiv topic:hep-ph |
arxiv_dataset-74491606.06993 | Exact mean integrated squared error and bandwidth selection for kernel
distribution function estimators
stat.ME
An exact, closed form, and easy to compute expression for the mean integrated
squared error (MISE) of a kernel estimator of a normal mixture cumulative
distribution function is derived for the class of arbitrary order
Gaussian-based kernels. Comparisons are made with MISE of the empirical
distribution function, the infeasible minimum MISE of kernel estimators, and
the asymptotically optimal second order uniform kernel. The results afford
straightforward extensions to other classes of kernel functions and
distributions. The analysis also offers a guide on when to use higher order
kernels in distribution function estimation.
A simple plug-in method of simultaneously selecting the optimal bandwidth and
kernel order is proposed based on a non-asymptotic approximation of the unknown
distribution by a normal mixture. A simulation study shows that the method
works well in finite samples, thus providing a viable alternative to existing
bandwidth selection procedures.
| arxiv topic:stat.ME |
arxiv_dataset-74501606.07093 | On the Lebesgue Constant of Weighted Leja Points for Lagrange
Interpolation on Unbounded Domains
math.NA
This work focuses on weighted Lagrange interpolation on an unbounded domain,
and analyzes the Lebesgue constant for a sequence of weighted Leja points. The
standard Leja points are a nested sequence of points defined on a compact
subset of the real line, and can be extended to unbounded domains with the
introduction of a weight function $w:\mathbb{R}\rightarrow [0,1]$. Due to a
simple recursive formulation in one dimension, such abscissas provide a
foundation for high-dimensional approximation methods such as sparse grid
collocation, deterministic least squares, and compressed sensing. Just as in
the unweighted case of interpolation on a compact domain, we use results from
potential theory to prove that the Lebesgue constant for the Leja points grows
subexponentially with the number of interpolation nodes.
| arxiv topic:math.NA |
arxiv_dataset-74511606.07193 | A Unified Model for GRB Prompt Emission from Optical to $\gamma$-Rays:
Exploring GRBs as Standard Candles
astro-ph.HE astro-ph.CO
The origin of prompt emission from gamma ray bursts remains to be an open
question. Correlated prompt optical and gamma-ray emission observed in a
handful of GRBs strongly suggests a common emission region, but failure to
adequately fit the broadband GRB spectrum prompted the hypothesis of different
emission mechanisms for the low- and high-energy radiations. We demonstrate
that our multi-component model for GRB gamma-ray prompt emission provides an
excellent fit to GRB 110205A from optical to gamma-ray energies. Our results
show that the optical and highest gamma-ray emissions have the same spatial and
spectral origin, which is different from the bulk of the X- and softest
gamma-ray radiation. Finally, our accurate redshift estimate for GRB 110205A
demonstrates promise for using GRBs as cosmological standard candles.
| arxiv topic:astro-ph.HE astro-ph.CO |
arxiv_dataset-74521606.07293 | Can giant radio halos probe the merging rate of galaxy clusters?
astro-ph.CO astro-ph.GA
Radio and X-ray observations of galaxy clusters probe a direct link between
cluster mergers and giant radio halos (RH), suggesting that these sources can
be used as probes of the cluster merging rate with cosmic time. In this paper
we carry out an explorative study that combines the observed fractions of
merging clusters (fm) and RH (fRH) with the merging rate predicted by
cosmological simulations and attempt to infer constraints on merger properties
of clusters that appear disturbed in X-rays and of clusters with RH. We use
morphological parameters to identify merging systems and analyze the currently
largest sample of clusters with radio and X-ray data (M500>6d14 Msun, and
0.2<z<0.33, from the Planck SZ cluster catalogue). We found that in this sample
fm~62-67% while fRH~44-51%. The comparison of the theoretical f_m with the
observed one allows to constrain the combination (xi_m,tau_m), where xi_m and
tau_m are the minimum merger mass ratio and the timescale of merger-induced
disturbance. Assuming tau_m~ 2-3 Gyr, as constrained by simulations, we find
that the observed f_m matches the theoretical one for xi_m~0.1-0.18. This is
consistent with optical and near-IR observations of clusters in the sample
(xi_m~0.14-0.16). The fact that RH are found only in a fraction of merging
clusters may suggest that merger events generating RH are characterized by
larger mass ratio; this seems supported by optical/near-IR observations of RH
clusters in the sample (xi_min~0.2-0.25). Alternatively, RH may be generated in
all mergers but their lifetime is shorter than \tau_m (by ~ fRH/fm). This is an
explorative study, however it suggests that follow up studies using the
forthcoming radio surveys and adequate numerical simulations have the potential
to derive quantitative constraints on the link between cluster merging rate and
RH at different cosmic epochs and for different cluster masses.
| arxiv topic:astro-ph.CO astro-ph.GA |
arxiv_dataset-74531606.07393 | Artificial intelligence applied to the automatic analysis of absorption
spectra. Objective measurement of the fine structure constant
astro-ph.IM
A new and automated method is presented for the analysis of high-resolution
absorption spectra. Three established numerical methods are unified into one
"artificial intelligence" process: a genetic algorithm (GVPFIT); non-linear
least-squares with parameter constraints (VPFIT); and Bayesian Model Averaging
(BMA).
The method has broad application but here we apply it specifically to the
problem of measuring the fine structure constant at high redshift. For this we
need objectivity and reproducibility. GVPFIT is also motivated by the
importance of obtaining a large statistical sample of measurements of
$\Delta\alpha/\alpha$. Interactive analyses are both time consuming and complex
and automation makes obtaining a large sample feasible.
In contrast to previous methodologies, we use BMA to derive results using a
large set of models and show that this procedure is more robust than a human
picking a single preferred model since BMA avoids the systematic uncertainties
associated with model choice.
Numerical simulations provide stringent tests of the whole process and we
show using both real and simulated spectra that the unified automated fitting
procedure out-performs a human interactive analysis. The method should be
invaluable in the context of future instrumentation like ESPRESSO on the VLT
and indeed future ELTs.
We apply the method to the $z_{abs} = 1.8389$ absorber towards the $z_{em} =
2.145$ quasar J110325-264515. The derived constraint of $\Delta\alpha/\alpha =
3.3 \pm 2.9 \times 10^{-6}$ is consistent with no variation and also consistent
with the tentative spatial variation reported in Webb et al (2011) and King et
al (2012).
| arxiv topic:astro-ph.IM |
arxiv_dataset-74541606.07493 | Sort Story: Sorting Jumbled Images and Captions into Stories
cs.CL cs.AI cs.CV cs.LG
Temporal common sense has applications in AI tasks such as QA, multi-document
summarization, and human-AI communication. We propose the task of sequencing --
given a jumbled set of aligned image-caption pairs that belong to a story, the
task is to sort them such that the output sequence forms a coherent story. We
present multiple approaches, via unary (position) and pairwise (order)
predictions, and their ensemble-based combinations, achieving strong results on
this task. We use both text-based and image-based features, which depict
complementary improvements. Using qualitative examples, we demonstrate that our
models have learnt interesting aspects of temporal common sense.
| arxiv topic:cs.CL cs.AI cs.CV cs.LG |
arxiv_dataset-74551606.07593 | Relations and representations of QCD amplitudes
hep-th hep-ph
In this talk we review relations and representations of primitive QCD tree
amplitudes. Topics covered include the BCJ relations, the CHY representation,
and the KLT relations. We will put a special emphasis on how these relations
and representations generalise from pure Yang-Mills theory to QCD. The
generalisation of the KLT relations from pure Yang-Mills to QCD includes the
case of massive quarks. On the gravity side we then obtain hypothetical
particles interacting with gravitational strength, which can be massive and
non-relativistic.
| arxiv topic:hep-th hep-ph |
arxiv_dataset-74561606.07693 | Cosmic ray interactions in the solar system: The Gerasimova-Zatsepin
effect
astro-ph.HE hep-ex
The Gerasimova-Zatsepin effect of collisions of ultra-high-energy cosmic ray
nuclei with photons emitted by the sun may cause two simultaneous air showers
on Earth. This effect is simulated using the full energy spectrum of solar
photons, ray tracing through the interplanetary magnetic field and upper limit
values for the iron and oxygen cosmic ray fluxes. Only the most abundant
interactions in which a single proton is emitted from the nucleus are
considered. For the first time the distributions of distances between the
individual showers at Earth as a function of the distance of the primary cosmic
ray to the Sun are shown. These distributions are used to estimate the
capabilities of current detector arrays to measure the Gerasimova-Zatsepin
effect and to show that a dedicated array is capable of measuring this effect.
| arxiv topic:astro-ph.HE hep-ex |
arxiv_dataset-74571606.07793 | The Higgs singlet extension at LHC Run 2
hep-ph
We discuss the current status of theoretical and experimental constraints on
the real Higgs singlet extension of the Standard Model. For the second neutral
(non-standard) Higgs boson the mass range up to 1 TeV accessible at past and
current collider experiments is considered. We furthermore discuss electroweak
corrections to the H to hh partial decay width within this model.
| arxiv topic:hep-ph |
arxiv_dataset-74581606.07893 | The Dimension of One-step Idempotent Right Modular Quasigroups
math.RA
We prove that one-step idempotent right modular groupoids are quasigroups.
The dimension of such quasigroups is defined and all such quasigroups of
dimensions 2,3 and 4 are determined.
| arxiv topic:math.RA |
arxiv_dataset-74591606.07993 | Learning for Biomedical Information Extraction: Methodological Review of
Recent Advances
cs.CL
Biomedical information extraction (BioIE) is important to many applications,
including clinical decision support, integrative biology, and
pharmacovigilance, and therefore it has been an active research. Unlike
existing reviews covering a holistic view on BioIE, this review focuses on
mainly recent advances in learning based approaches, by systematically
summarizing them into different aspects of methodological development. In
addition, we dive into open information extraction and deep learning, two
emerging and influential techniques and envision next generation of BioIE.
| arxiv topic:cs.CL |
arxiv_dataset-74601606.08093 | Characterization of the second- and third-order nonlinear optical
susceptibilities of monolayer MoS$_2$ using multiphoton microscopy
cond-mat.mes-hall physics.optics
We report second- and third-harmonic generation in monolayer MoS$_\mathrm{2}$
as a tool for imaging and accurately characterizing the material's nonlinear
optical properties under 1560 nm excitation. Using a surface nonlinear optics
treatment, we derive expressions relating experimental measurements to second-
and third-order nonlinear sheet susceptibility magnitudes, obtaining values of
$|\chi_s^{(2)}|=2.0\times10^{-20}$ m$^2$ V$^{-1}$ and for the first time for
monolayer MoS$_\mathrm{2}$, $|\chi_s^{(3)}|=1.7\times10^{-28}$ m$^3$ V$^{-2}$.
These sheet susceptibilities correspond to effective bulk nonlinear
susceptibility values of $|\chi_{b}^{(2)}|=2.9\times10^{-11}$ m V$^{-1}$ and
$|\chi_{b}^{(3)}|=2.4\times10^{-19}$ m$^2$ V$^{-2}$, accounting for the sheet
thickness. Experimental comparisons between MoS$_\mathrm{2}$ and graphene are
also performed, demonstrating $\sim$3.4 times stronger third-order sheet
nonlinearity in monolayer MoS$_\mathrm{2}$, highlighting the material's
potential for nonlinear photonics in the telecommunications C band.
| arxiv topic:cond-mat.mes-hall physics.optics |
arxiv_dataset-74611606.08193 | From Chio Pivotal Condensation to the Matrix-Tree theorem
math.CO
We show a determinant identity which generalizes both the Chio pivotal
condensation theorem and the Matrix-Tree theorem.
| arxiv topic:math.CO |
arxiv_dataset-74621606.08293 | Studies of entropy measures concerning the gaps of prime numbers
math.GM
The Shannon entropy is used as a basis for applying different lemmas and
conjectures concerning the set of gaps between prime numbers G_p , thus
estimating several measures of it. The same procedures are applied to
artificially created number sets, to compare the size of their entropy against
G_p .
| arxiv topic:math.GM |
arxiv_dataset-74631606.08393 | Location of the Adsorption Transition for Lattice Polymers
math-ph math.MP math.PR
We consider various lattice models of polymers: lattice trees, lattice
animals, and self-avoiding walks. The polymer interacts with a surface
(hyperplane), receiving a unit energy reward for each site in the surface.
There is an adsorption transition of the polymer at a critical value of
$\beta$, the inverse temperature. We present a new proof of the result of
Hammersley, Torrie, and Whittington (1982) that the transition occurs at a
strictly positive value of $\beta$ when the surface is impenetrable, i.e. when
the polymer is restricted to a half-space. In contrast, for a penetrable
surface, it is an open problem to prove that the transition occurs at $\beta=0$
(i.e., infinite temperature). We reduce this problem to showing that the
fraction of N-site polymers whose span is less than $N/\log^2 N$ is not too
small.
| arxiv topic:math-ph math.MP math.PR |
arxiv_dataset-74641606.08493 | Diagnostics of Coronal Magnetic Fields Through the Hanle Effect in UV
and IR Lines
astro-ph.SR
The plasma thermodynamics in the solar upper atmosphere, particularly in the
corona, are dominated by the magnetic field, which controls the flow and
dissipation of energy. The relative lack of knowledge of the coronal vector
magnetic field is a major handicap for progress in coronal physics. This makes
the development of measurement methods of coronal magnetic fields a high
priority in solar physics. The Hanle effect in the UV and IR spectral lines is
a largely unexplored diagnostic. We use magnetohydrodynamic (MHD) simulations
to study the magnitude of the signal to be expected for typical coronal
magnetic fields for selected spectral lines in the UV and IR wavelength ranges,
namely the H I Ly-$\alpha$ and the He I 10830 {\AA} lines. We show that the
selected lines are useful for reliable diagnosis of coronal magnetic fields.
The results show that the combination of polarization measurements of spectral
lines with different sensitivities to the Hanle effect may be most appropriate
for deducing coronal magnetic properties from future observations.
| arxiv topic:astro-ph.SR |
arxiv_dataset-74651606.08593 | Exotic hadrons: review and perspectives
hep-ph hep-ex nucl-th
The physics of exotic hadrons is revisited and reviewed, with emphasis on
flavour configurations which have not yet been investigated. The constituent
quark model of multiquark states is discussed in some detail, as it can serve
as a guide for more elaborate approaches.
| arxiv topic:hep-ph hep-ex nucl-th |
arxiv_dataset-74661606.08693 | Anomalous diffusion in convergence to effective ergodicity
cond-mat.stat-mech
Power-law exponents in the convergence to effective ergodicity is quantified
for Ising-Lenz model in one dimension. Modified Thirumalai-Mountain (TM) metric
for magnetisation is computed for the range of temperature values under
strongly correlated dynamics. In producing evolution of TM metric over time,
time-averaged dynamics is generated by using Metropolis and Glauber
single-spin-flip dynamics, and ensemble-averaged dynamics with an exact
solution. Superdiffusive behaviour is numerically identified in the parameter
regimes studied, i.e., power-law exponents, $\alpha > 1.0$.
| arxiv topic:cond-mat.stat-mech |
arxiv_dataset-74671606.08793 | Modeling Industrial ADMET Data with Multitask Networks
stat.ML
Deep learning methods such as multitask neural networks have recently been
applied to ligand-based virtual screening and other drug discovery
applications. Using a set of industrial ADMET datasets, we compare neural
networks to standard baseline models and analyze multitask learning effects
with both random cross-validation and a more relevant temporal validation
scheme. We confirm that multitask learning can provide modest benefits over
single-task models and show that smaller datasets tend to benefit more than
larger datasets from multitask learning. Additionally, we find that adding
massive amounts of side information is not guaranteed to improve performance
relative to simpler multitask learning. Our results emphasize that multitask
effects are highly dataset-dependent, suggesting the use of dataset-specific
models to maximize overall performance.
| arxiv topic:stat.ML |
arxiv_dataset-74681606.08893 | Efficiently Inferring Pairwise Subtree Prune-and-Regraft Adjacencies
between Phylogenetic Trees
cs.DS
We develop a time-optimal $O(mn^2)$-time algorithm to construct the subtree
prune-regraft (SPR) graph on a collection of m phylogenetic trees with n
leaves. This improves on the previous bound of $O(mn^3)$. Such graphs are used
to better understand the behaviour of phylogenetic methods and recommend
parameter choices and diagnostic criteria. The limiting factor in these
analyses has been the difficulty in constructing such graphs for large numbers
of trees. We also develop the first efficient algorithms for constructing the
nearest-neighbor interchange (NNI) and tree bisection-and-reconnection (TBR)
graphs
| arxiv topic:cs.DS |
arxiv_dataset-74691606.08993 | Nonlinear argumental oscillators: Stability criterion and attractor's
capture probability
nlin.CD
The behaviour of a space-modulated, so-called "argumental" oscillator is
studied, which is represented by a model having an even-parity space-modulating
function. Analytic expressions of a stability criterion and of discrete energy
levels are given. Using an integrating factor and a Van der Pol representation
in the (amplitude, phase) space, an approximate implicit closed-form of the
solution is given. The probability to enter a stable-oscillation regime from
given initial conditions is calculated in symbolic form. These results allow an
analytic approach to stability and bifurcations of the system. They also allow
an assessment of the risk of occurrence of sustained large-amplitude
oscillations, when the phenomenon is to be avoided, and an assessment of the
conditions to apply to obtain oscillations whenever the phenomenon is desired.
| arxiv topic:nlin.CD |
arxiv_dataset-74701606.09093 | An IoT Architecture for Wide Area Measurement Systems: a Virtualized PMU
Based Approach
cs.NI
Internet of Things (IoT) technologies are pervading different application
domains by relying on sensing and actuating devices that share, process and
present meaningful real-world information. One of the most important of these
domains is certainly the Smart Grid (SG), where the use of advanced measurement
and control equipment and the diffusion of communication technologies are
making an adaptive, reliable, and efficient management of the energy possible,
with several new applications. In this scenario, this paper focuses on one of
the major IoT features, which is the virtualization, and proposes an IoT
solution for wide area measurement systems where virtualized phasor measurement
resources are introduced. Such a solution is intended to make a programmable
and smart environment fostering interoperability, reusability and flexibility
of SG services. The performance of the system is evaluated for both the traffic
generated and the latency to understand which scenarios can benefit from its
deployment.
| arxiv topic:cs.NI |
arxiv_dataset-74711606.09193 | Small coherence implies the weak Null Space Property
math.ST stat.ML stat.TH
In the Compressed Sensing community, it is well known that given a matrix $X
\in \mathbb R^{n\times p}$ with $\ell_2$ normalized columns, the Restricted
Isometry Property (RIP) implies the Null Space Property (NSP). It is also well
known that a small Coherence $\mu$ implies a weak RIP, i.e. the singular values
of $X_T$ lie between $1-\delta$ and $1+\delta$ for "most" index subsets $T
\subset \{1,\ldots,p\}$ with size governed by $\mu$ and $\delta$. In this short
note, we show that a small Coherence implies a weak Null Space Property, i.e.
$\Vert h_T\Vert_2 \le C \ \Vert h_{T^c}\Vert_1/\sqrt{s}$ for most $T \subset
\{1,\ldots,p\}$ with cardinality $|T|\le s$. We moreover prove some singular
value perturbation bounds that may also prove useful for other applications.
| arxiv topic:math.ST stat.ML stat.TH |
arxiv_dataset-74721606.09293 | Cascade photons as test of protons in UHECR
astro-ph.HE
An isotropic component of high energy $\gamma$-ray spectrum measured by Fermi
LAT constrains the proton component of UHECR. The strongest restriction comes
from the highest, $(580-820)$ GeV, energy bin. One more constraint on the
proton component is provided by the IceCube upper bound on ultrahigh energy
cosmogenic neutrino flux. We study the influence of these restrictions on the
source properties, such as evolution and distribution of sources, their energy
spectrum and admixture of nuclei. We also study the sensitivity of restrictions
to various Fermi LAT galactic foreground models (model B being less
restrictive), to the choice of extragalactic background light model and to
overall normalization of the energy spectrum. We claim that the
$\gamma$-ray-cascade constraints are stronger than the neutrino ones, and that
however many proton models are viable. The basic parameters of such models are
relatively large $\gamma_g$ and not very large $z_{\max}$. The allowance for
H$e^4$ admixture also relaxes the restrictions. However we foresee that future
CTA measurements of $\gamma$-ray spectrum at $E_\gamma \simeq (600 - 800)$ GeV,
as well as resolving of more individual $\gamma$-ray sources, may rule out the
proton-dominated cosmic ray models.
| arxiv topic:astro-ph.HE |
arxiv_dataset-74731606.09393 | Linearized stability theorem for invariant and quasi-invariant parabolic
differential equations in Banach manifolds with applications to free boundary
problems
math.AP math.CA math.DG math.DS math.FA
If a differential equation in a Banach manifold is invariant or
quasi-invariant under the action of one or more Lie groups, then its stationary
points cannot be isolated, so that classical linearized stability theorem does
not apply to it. The first main purpose of this paper is to establish a
linearized stability theorem for parabolic differential equations in Banach
manifolds which are either invariant or quasi-invariant under actions of a
number of Lie groups. The second purpose of this paper is to apply this theorem
to analyze stability of stationary solutions of some free boundary problems. In
order to apply the abstract result to concrete free boundary problems, Banach
manifold made up of certain kind of domains such as simple domains in
${\mathbf{R}}^n$ is a fundamental tool which seems to have not been
well-studied in the literature yet. Hence in this paper we also make some basic
investigation to a such manifold. In Section 5 we use Nash-Moser implicit
function theorem to prove an interesting result for an obstacle problem which
says that if the domain $\Omega$ of this obstacle problem is a small
perturbation of a sphere then its interface $\Gamma$ is smooth and depends on
$\Omega$ smoothly. By using these results, in the last section we prove
asymptotic stability of radial stationary solution of a free boundary problem
modeling the growth of necrotic tumors, which has been kept open for over ten
years.
| arxiv topic:math.AP math.CA math.DG math.DS math.FA |
arxiv_dataset-74741606.09493 | Comments on "sub-KBT micro-electromechanical irreversible logic gate"
cs.ET
In a recent article, Nature Communications 7 (2016) 12068, the authors
claimed that they demonstrated sub-kBT energy dissipation at elementary logic
operations. However, the argumentation is invalid because it neglects the
dominant source of energy dissipation, namely, the charging energy of the
capacitance of the input electrode, which totally dissipates during the full
(0-1-0) cycle of logic values. The neglected dissipation phenomenon is
identical with the mechanism that leads to the lower physical limit of
dissipation (70-100 kBT) in today's microprocessors (CMOS logic) and in any
other system with thermally activated errors thus the same limit holds for the
new scheme, too.
| arxiv topic:cs.ET |
arxiv_dataset-74751606.09593 | Unitarity and positivity constraints for CFT at large central charge
hep-th
We consider the four-point correlator of the stress tensor multiplet in
${\cal N}=4$ SYM in the limit of large central charge $c \sim N^2$. For finite
values of $g^2N$ single-trace intermediate operators arise at order $1/c$ and
this leads to specific poles in the Mellin representation of the correlator.
The sign of the residue at these poles is fixed by unitarity. We consider
solutions consistent with crossing symmetry and this pole structure. We show
that in a certain regime all solutions result in a negative contribution to the
anomalous dimension of twist four operators. The reason behind this is a
positivity property of Mack polynomials that leads to a positivity condition
for the Mellin amplitude. This positivity condition can also be proven by
assuming the correct Regge behaviour for the Mellin amplitude. For large $g^2N$
we recover a tower of solutions in one to one correspondence with local
interactions in a effective field theory in the $AdS$ bulk, with the
appropriate suppression factors, and with definite overall signs. These signs
agree with the signs that would follow from causality constraints on the
effective field theory. The positivity constraints arising from CFT for the
Mellin amplitude take a very similar form to the causality constraint for the
forward limit of the S-matrix.
| arxiv topic:hep-th |
arxiv_dataset-74761607.00049 | The Steinhaus-Weil property: its converse, subcontinuity and Solecki
amenability
math.GN
The Steinhaus-Weil theorem that concerns us here is the simple, or classical,
`interior-points' property -- that in a Polish topological group a
non-negligible set B has the identity as an interior point of $BB^{-1}$. There
are various converses; the one that mainly concerns us is due to Simmons and
Mospan. Here the group is locally compact, so we have a Haar reference measure
$\eta$. The Simmons-Mospan theorem states that a (regular Borel) measure has
such a Steinhaus-Weil property if and only if it is absolutely continuous with
respect to the Haar measure. In Part I (Propositions 1-7, Theorems 1-4) we
exploit the connection between the interior-points property and a selective
form of infinitesimal invariance afforded by a certain family of selective
reference measures $\sigma$, drawing on Solecki's amenability at 1 (and using
Fuller's notion of subcontinuity). In Part II (Propositions 8, 9, Theorems 5,
6) we develop a number of relatives of the Simmons-Mospan theorem. In Part III
(Theorems 7, 8) we link this with topologies of Weil type. We close in Part IV
with Propositions 12-13 and Theorem B -- concerning the `composite
interior-point' property (of $AB^{-1}$) and the Borell `relative
interior-point' property (relative to the Cameron-Martin space) -- and
complements.
| arxiv topic:math.GN |
arxiv_dataset-74771607.00149 | A non-standard analysis of a cultural icon: The case of Paul Halmos
math.HO math.FA math.LO
We examine Paul Halmos' comments on category theory, Dedekind cuts, devil
worship, logic, and Robinson's infinitesimals. Halmos' scepticism about
category theory derives from his philosophical position of naive set-theoretic
realism. In the words of an MAA biography, Halmos thought that mathematics is
"certainty" and "architecture" yet 20th century logic teaches us is that
mathematics is full of uncertainty or more precisely incompleteness. If the
term architecture meant to imply that mathematics is one great solid castle,
then modern logic tends to teach us the opposite lession, namely that the
castle is floating in midair. Halmos' realism tends to color his judgment of
purely scientific aspects of logic and the way it is practiced and applied. He
often expressed distaste for nonstandard models, and made a sustained effort to
eliminate first-order logic, the logicians' concept of interpretation, and the
syntactic vs semantic distinction. He felt that these were vague, and sought to
replace them all by his polyadic algebra. Halmos claimed that Robinson's
framework is "unnecessary" but Henson and Keisler argue that Robinson's
framework allows one to dig deeper into set-theoretic resources than is common
in Archimedean mathematics. This can potentially prove theorems not accessible
by standard methods, undermining Halmos' criticisms.
Keywords: Archimedean axiom; bridge between discrete and continuous
mathematics; hyperreals; incomparable quantities; indispensability; infinity;
mathematical realism; Robinson.
| arxiv topic:math.HO math.FA math.LO |
arxiv_dataset-74781607.00249 | Distributed Nonconvex Multiagent Optimization Over Time-Varying Networks
cs.DC cs.SY math.OC
We study nonconvex distributed optimization in multiagent networks where the
communications between nodes is modeled as a time-varying sequence of arbitrary
digraphs. We introduce a novel broadcast-based distributed algorithmic
framework for the (constrained) minimization of the sum of a smooth (possibly
nonconvex and nonseparable) function, i.e., the agents' sum-utility, plus a
convex (possibly nonsmooth and nonseparable) regularizer. The latter is usually
employed to enforce some structure in the solution, typically sparsity. The
proposed method hinges on Successive Convex Approximation (SCA) techniques
coupled with i) a tracking mechanism instrumental to locally estimate the
gradients of agents' cost functions; and ii) a novel broadcast protocol to
disseminate information and distribute the computation among the agents.
Asymptotic convergence to stationary solutions is established. A key feature of
the proposed algorithm is that it neither requires the double-stochasticity of
the consensus matrices (but only column stochasticity) nor the knowledge of the
graph sequence to implement. To the best of our knowledge, the proposed
framework is the first broadcast-based distributed algorithm for convex and
nonconvex constrained optimization over arbitrary, time-varying digraphs.
Numerical results show that our algorithm outperforms current schemes on both
convex and nonconvex problems.
| arxiv topic:cs.DC cs.SY math.OC |
arxiv_dataset-74791607.00349 | Painlev\'e analysis for two 1D parabolic-parabolic models of chemotaxis;
some travelling wave solutions
nlin.SI
In this paper we study the Painlev\'e analysis for two models of chemotaxis.
We find that in some cases the reductions of these models in terms of
travelling wave variable allow exact analytical solutions.
| arxiv topic:nlin.SI |
arxiv_dataset-74801607.00449 | Theoretical Simulation of 87Rb Absorption Spectrum in a Thermal Cell
physics.atom-ph physics.optics
In this paper, we present a theoretical simulation of 87Rb absorption
spectrum in a thermal cm-cell which is adaptive to the experimental
observation. In experiment, the coupling and probe beams are configured to
copropagate but perpendicular polarized, making up to five velocity selective
optical pumping (VSOP) absorption dips able to be identified. A $\Lambda$-type
electromagnetically induced transparency (EIT) is also observed for each group
of velocity-selected atoms. The spectrum by only sweeping the probe beam can be
decomposed into a combination of Doppler-broadened background and three VSOP
dips for each group of velocity-selected atoms, companied by an EIT peak. This
proposed theoretical model can be used to simulate the spectrum adaptive to the
experimental observation by non-linear least-square fit method. The fit for
high quality of experimental observation can determine valuable transition
parameters such as decaying rates and coupling beam power accurately.
| arxiv topic:physics.atom-ph physics.optics |
arxiv_dataset-74811607.00549 | A Subgradient Method for Free Material Design
math.OC
A small improvement in the structure of the material could save the
manufactory a lot of money. The free material design can be formulated as an
optimization problem. However, due to its large scale, second-order methods
cannot solve the free material design problem in reasonable size. We formulate
the free material optimization (FMO) problem into a saddle-point form in which
the inverse of the stiffness matrix A(E) in the constraint is eliminated. The
size of A(E) is generally large, denoted as N by N. This is the first
formulation of FMO without A(E). We apply the primal-dual subgradient method
[17] to solve the restricted saddle-point formula. This is the first
gradient-type method for FMO. Each iteration of our algorithm takes a total of
$O(N^2)$ foating-point operations and an auxiliary vector storage of size O(N),
compared with formulations having the inverse of A(E) which requires $O(N^3)$
arithmetic operations and an auxiliary vector storage of size $O(N^2)$. To
solve the problem, we developed a closed-form solution to a semidefinite least
squares problem and an efficient parameter update scheme for the gradient
method, which are included in the appendix. We also approximate a solution to
the bounded Lagrangian dual problem. The problem is decomposed into small
problems each only having an unknown of k by k (k = 3 or 6) matrix, and can be
solved in parallel. The iteration bound of our algorithm is optimal for general
subgradient scheme. Finally we present promising numerical results.
| arxiv topic:math.OC |
arxiv_dataset-74821607.00649 | A novel technique for the measurement of the avalanche fluctuation of
gaseous detectors
physics.ins-det hep-ex
We have developed a novel technique for the measurement of the avalanche
fluctuation of gaseous detectors using a UV laser. The technique is simple and
requires a short data-taking time of about ten minutes. Furthermore, it is
applicable for relatively low gas gains. Our experimental setup as well as the
measurement principle, and the results obtained with a stack of Gas Electron
Multipliers (GEMs) operated in several gas mixtures are presented.
| arxiv topic:physics.ins-det hep-ex |
arxiv_dataset-74831607.00749 | Graded comodule categories with enough projectives
math.RA math.AT
It is well-known that the category of comodules over a flat Hopf algebroid is
abelian but typically fails to have enough projectives, and more generally, the
category of graded comodules over a graded flat Hopf algebroid is abelian but
typically fails to have enough projectives. In this short paper we prove that
the category of connective graded comodules over a connective, graded, flat,
finite-type Hopf algebroid has enough projectives. Applications to algebraic
topology are given: the Hopf algebroids of stable co-operations in complex
bordism, Brown-Peterson homology, and classical mod $p$ homology all have the
property that their categories of connective graded comodules have enough
projectives. We also prove that categories of connective graded comodules over
appropriate Hopf algebras fail to be equivalent to categories of graded
connective modules over a ring.
| arxiv topic:math.RA math.AT |
arxiv_dataset-74841607.00849 | Plyades: A Python Library for Space Mission Design
astro-ph.IM
Plyades: A Python Library for Space Mission Design Designing a space mission
is a computation-heavy task. Software tools that conduct the necessary
numerical simulations and optimizations are therefore indispensable. The
usability of existing software, written in Fortran and MATLAB, suffers because
of high complexity, low levels of abstraction and out-dated programming
practices. We propose Python as a viable alternative for astrodynamics tools
and demonstrate the proof-of-concept library Plyades which combines powerful
features with Pythonic ease of use.
| arxiv topic:astro-ph.IM |
arxiv_dataset-74851607.00949 | Duration of classicality in highly degenerate interacting Bosonic
systems
hep-ph astro-ph.CO cond-mat.stat-mech hep-th
We study sets of oscillators that have high quantum occupancy and that
interact by exchanging quanta. It is shown by analytical arguments and
numerical simulation that such systems obey classical equations of motion only
on time scales of order their relaxation time $\tau$ and not longer than that.
The results are relevant to the cosmology of axions and axion-like particles.
| arxiv topic:hep-ph astro-ph.CO cond-mat.stat-mech hep-th |
arxiv_dataset-74861607.01049 | Synchrotron Emission from Dark Matter Annihilation: Predictions for
Constraints from Non-detections of Galaxy Clusters with New Radio Surveys
astro-ph.CO astro-ph.HE hep-ph
The annihilation of dark matter particles is expected to yield a broad
radiation spectrum via the production of Standard Model particles in
astrophysical environments. In particular, electrons and positrons from dark
matter annihilation produce synchrotron radiation in the presence of magnetic
fields. Galaxy clusters are the most massive collapsed structures in the
universe, and are known to host $\sim\mu$G-scale magnetic fields. They are
therefore ideal targets to search for, or to constrain the synchrotron signal
from dark matter annihilation. In this work we use the expected sensitivities
of several planned surveys from the next generation of radio telescopes to
predict the constraints on dark matter annihilation models which will be
achieved in the case of non-detections of diffuse radio emission from galaxy
clusters. Specifically, we consider the Tier 1 survey planned for the Low
Frequency Array (LOFAR) at 120 MHz, the EMU survey planned for the Australian
Square Kilometre Array Pathfinder (ASKAP) at 1.4 GHz, and planned surveys for
APERTIF at 1.4 GHz. We find that, for massive clusters and dark matter masses
$\lesssim 100$ GeV, the predicted limits on the annihilation cross section
would rule out vanilla thermal relic models for even the shallow LOFAR Tier 1,
ASKAP, and APERTIF surveys.
| arxiv topic:astro-ph.CO astro-ph.HE hep-ph |
arxiv_dataset-74871607.01149 | Target-Side Context for Discriminative Models in Statistical Machine
Translation
cs.CL
Discriminative translation models utilizing source context have been shown to
help statistical machine translation performance. We propose a novel extension
of this work using target context information. Surprisingly, we show that this
model can be efficiently integrated directly in the decoding process. Our
approach scales to large training data sizes and results in consistent
improvements in translation quality on four language pairs. We also provide an
analysis comparing the strengths of the baseline source-context model with our
extended source-context and target-context model and we show that our extension
allows us to better capture morphological coherence. Our work is freely
available as part of Moses.
| arxiv topic:cs.CL |
arxiv_dataset-74881607.01249 | TTC: A Tensor Transposition Compiler for Multiple Architectures
cs.MS cs.PF
We consider the problem of transposing tensors of arbitrary dimension and
describe TTC, an open source domain-specific parallel compiler. TTC generates
optimized parallel C++/CUDA C code that achieves a significant fraction of the
system's peak memory bandwidth. TTC exhibits high performance across multiple
architectures, including modern AVX-based systems (e.g.,~Intel Haswell, AMD
Steamroller), Intel's Knights Corner as well as different CUDA-based GPUs such
as NVIDIA's Kepler and Maxwell architectures. We report speedups of TTC over a
meaningful baseline implementation generated by external C++ compilers; the
results suggest that a domain-specific compiler can outperform its general
purpose counterpart significantly: For instance, comparing with Intel's latest
C++ compiler on the Haswell and Knights Corner architecture, TTC yields
speedups of up to $8\times$ and $32\times$, respectively. We also showcase
TTC's support for multiple leading dimensions, making it a suitable candidate
for the generation of performance-critical packing functions that are at the
core of the ubiquitous BLAS 3 routines.
| arxiv topic:cs.MS cs.PF |
arxiv_dataset-74891607.01349 | Rate of convergence of attractors for semilinear singularly perturbed
problems: parabolic equations with large diffusion
math.AP
We exhibit a singularly perturbed parabolic problems for which the asymptotic
behavior can be described by an one-dimensional ordinary differential equation.
We estimate the continuity of attractors in the Hausdorff metric by rate of
convergence of resolvent operator.
| arxiv topic:math.AP |
arxiv_dataset-74901607.01449 | Stochastic multi-scale models of competition within heterogeneous
cellular populations: simulation methods and mean-field analysis
physics.bio-ph q-bio.CB
We propose a modelling framework to analyse the stochastic behaviour of
heterogeneous, multi-scale cellular populations. We illustrate our methodology
with a particular example in which we study a population with an
oxygen-regulated proliferation rate. Our formulation is based on an
age-dependent stochastic process. Cells within the population are characterised
by their age. The age-dependent (oxygen-regulated) birth rate is given by a
stochastic model of oxygen-dependent cell cycle progression. We then formulate
an age-dependent birth-and-death process, which dictates the time evolution of
the cell population. The population is under a feedback loop which controls its
steady state size: cells consume oxygen which in turns fuels cell
proliferation. We show that our stochastic model of cell cycle progression
allows for heterogeneity within the cell population induced by stochastic
effects. Such heterogeneous behaviour is reflected in variations in the
proliferation rate. Within this set-up, we have established three main results.
First, we have shown that the age to the G1/S transition, which essentially
determines the birth rate, exhibits a remarkably simple scaling behaviour. This
allows for a huge simplification of our numerical methodology. A further result
is the observation that heterogeneous populations undergo an internal process
of quasi-neutral competition. Finally, we investigated the effects of
cell-cycle-phase dependent therapies (such as radiation therapy) on
heterogeneous populations. In particular, we have studied the case in which the
population contains a quiescent sub-population. Our mean-field analysis and
numerical simulations confirm that, if the survival fraction of the therapy is
too high, rescue of the quiescent population occurs. This gives rise to
emergence of resistance to therapy since the rescued population is less
sensitive to therapy.
| arxiv topic:physics.bio-ph q-bio.CB |
arxiv_dataset-74911607.01549 | Desarguesian spreads and field reduction for elements of the semilinear
group
math.CO
The goal of this note is to create a sound framework for the interplay
between field reduction for finite projective spaces, the general semilinear
groups acting on the defining vector spaces and the projective semilinear
groups. This approach makes it possible to reprove a result of Dye on the
stabiliser in PGL of a Desarguesian spread in a more elementary way, and extend
it to P{\Gamma}L(n, q). Moreover a result of Drudge [5] relating Singer cycles
with Desarguesian spreads, as well as a result on subspreads (by Sheekey,
Rottey and Van de Voorde [19]) are reproven in a similar elementary way.
Finally, we try to use this approach to shed a light on Condition (A) of
Csajbok and Zanella, introduced in the study of linear sets [4].
| arxiv topic:math.CO |
arxiv_dataset-74921607.01649 | Randomized methods for matrix computations
math.NA
The purpose of this text is to provide an accessible introduction to a set of
recently developed algorithms for factorizing matrices. These new algorithms
attain high practical speed by reducing the dimensionality of intermediate
computations using randomized projections. The algorithms are particularly
powerful for computing low-rank approximations to very large matrices, but they
can also be used to accelerate algorithms for computing full factorizations of
matrices. A key competitive advantage of the algorithms described is that they
require less communication than traditional deterministic methods.
| arxiv topic:math.NA |
arxiv_dataset-74931607.01749 | Z+jet production at NNLO
hep-ph
We give a brief overview of our calculation of the next-to-next-to-leading
order (NNLO) QCD corrections to Z+jet production in hadronic collisions.
Phenomenological results are presented which comprise various differential
distributions for 8 TeV proton-proton collisions. A significant reduction of
the scale uncertainties is observed throughout as we move from NLO to NNLO. We
further discuss how this calculation can be used to describe the inclusive
Z-boson production at large transverse momentum. To this end, the theory
prediction is compared to the measurements performed by the ATLAS and CMS
collaborations at a centre-of-mass energy of 8 TeV. Here, the inclusion of NNLO
QCD effects are found to result in a substantial improvement in the agreement
between theory and data for the normalised distributions.
| arxiv topic:hep-ph |
arxiv_dataset-74941607.01849 | Coherent and Dynamic Beam Splitting based on Light Storage in Cold Atoms
quant-ph
We demonstrate a coherent and dynamic beam splitter based on light storage in
cold atoms. An input weak laser pulse is first stored in a cold atom ensemble
via electromagnetically-induced transparency (EIT). A set of
counter-propagating control fields, applied at a later time, retrieves the
stored pulse into two output spatial modes. The high visibility interference
between the two output pulses clearly demonstrates that the beam splitting
process is coherent. Furthermore, by manipulating the control lasers, it is
possible to dynamically control the storage time, the power splitting ratio,
the relative phase, and the optical frequencies of the output pulses. The
active beam splitter demonstrated in this work is expected to significantly
reduce the resource requirement in photonic quantum information and in
all-optical information processing as a single cold atom ensemble can
functionally replace a variety of optical elements, including beam splitters,
mirrors, phase shifters, and optical quantum memories.
| arxiv topic:quant-ph |
arxiv_dataset-74951607.01949 | Higgs boson mass from gauge invariant operators
hep-ph
We make the assumption that the vacuum correlators of the gauge invariant
kinetic term of the Higgs doublet are the same before and after the spontaneous
symmetry breaking of the theory. Based on this we determine the mass of the
standard model Higgs boson at $m_h \approx 125.07$ GeV by considering one loop
and the most relevant two loop corrections. This result might suggest that
there is a single Higgs boson doublet that contributes to the electroweak
symmetry breaking.
| arxiv topic:hep-ph |
arxiv_dataset-74961607.02049 | First Evaluation of Dynamic Aperture at Injection for FCC-hh
physics.acc-ph
In the Hadron machine option, proposed in the context of the Future Circular
Colliders (FCC) study, the dipole field quality is expected to play an
important role, as in the LHC. A preliminary evaluation of the field quality of
dipoles, based on the Nb$_{3}$Sn technology, has been provided by the magnet
group. The effect of these field imperfections on the dynamic aperture, using
the present lattice design, is presented and first tolerances on the b$_3$ and
b$_5$ multipole components are evaluated.
| arxiv topic:physics.acc-ph |
arxiv_dataset-74971607.02149 | Nuclear Zemach Moments and Finite-Size Corrections to Allowed Beta Decay
nucl-th
The finite-size correction to $\beta$-decay plays an important role in
determining the expected antineutrino spectra from reactors at a level that is
important for the reactor-neutrino anomaly. Here we express the leading-order
finite-size correction to allowed $\beta$-decay in terms of Zemach moments. We
calculate the Zemach moments within a Hartree-Fock model using a Skyrme-like
energy density functional. We find that the Zemach moments are increased
relative to predictions based on the simple assumption of identical uniform
nuclear-charge and weak-transition densities. However, for allowed ground-state
to ground-state transitions in medium and heavy nuclei, the detailed nuclear
structure calculations do not change the finite-size corrections significantly
from the simple model predictions, and are only 10-15% larger than the latter
even though the densities differ significantly.
| arxiv topic:nucl-th |
arxiv_dataset-74981607.02249 | Low-Complexity Sub-band Digital Predistortion for Spurious Emission
Suppression in Noncontiguous Spectrum Access
cs.IT cs.SY math.IT
Noncontiguous transmission schemes combined with high power-efficiency
requirements pose big challenges for radio transmitter and power amplifier (PA)
design and implementation. Due to the nonlinear nature of the PA, severe
unwanted emissions can occur, which can potentially interfere with neighboring
channel signals or even desensitize the own receiver in frequency division
duplexing (FDD) transceivers. In this article, to suppress such unwanted
emissions, a low-complexity sub-band DPD solution, specifically tailored for
spectrally noncontiguous transmission schemes in low-cost devices, is proposed.
The proposed technique aims at mitigating only the selected spurious
intermodulation distortion components at the PA output, hence allowing for
substantially reduced processing complexity compared to classical linearization
solutions. Furthermore, novel decorrelation based parameter learning solutions
are also proposed and formulated, which offer reduced computing complexity in
parameter estimation as well as the ability to track time-varying features
adaptively. Comprehensive simulation and RF measurement results are provided,
using a commercial LTE-Advanced mobile PA, to evaluate and validate the
effectiveness of the proposed solution in real world scenarios. The obtained
results demonstrate that highly efficient spurious component suppression can be
obtained using the proposed solutions.
| arxiv topic:cs.IT cs.SY math.IT |
arxiv_dataset-74991607.02349 | Toward an integrated workforce planning framework using structured
equations
q-fin.GN
Strategic Workforce Planning is a company process providing best in class,
economically sound, workforce management policies and goals. Despite the
abundance of literature on the subject, this is a notorious challenge in terms
of implementation. Reasons span from the youth of the field itself to broader
data integration concerns that arise from gathering information from financial,
human resource and business excellence systems. This paper aims at setting the
first stones to a simple yet robust quantitative framework for Strategic
Workforce Planning exercises. First a method based on structured equations is
detailed. It is then used to answer two main workforce related questions: how
to optimally hire to keep labor costs flat? How to build an experience
constrained workforce at a minimal cost?
| arxiv topic:q-fin.GN |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.