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arxiv_dataset-71001603.00579 | The Effects of Orographic Geometry on Supercell Thunderstorms
physics.ao-ph
The effect of elongated bell-shaped mountain orientation on supercell
thunderstorms is numerically investigated using the Bryan Cloud Model 1 (CM1).
The orography is varied by three mountain heights and is varied in four
different positions, effectively producing 12 different terrain configurations.
It is found that the different orientations produce variations in the supercell
life cycle with shorter cycles for higher inflow rates. Furthermore, these
cycles are associated with the storm reaching its minimum intensity just after
a peak rain period. Moreover, the effect of stronger inflow was seen before
direct storm-terrain interactions started. The higher inflow also played a
significant role in increasing rainfall rate and areal extent, to the point
that further convection, associated with the cold pool, was triggered adding to
rainfall amount. Using a stricter form of the National Weather Service Tornado
Detection Algorithm to investigate the tornadic nature of simulated supercells;
it is found that terrain blocking effects are dominative and that elongating
the terrain axis approximately parallel to the propagation vector produced the
strongest potential to generate a tornadic supercell thunderstorm. Although the
simulated case with the highest mountain produced the most tornadic
thunderstorms it is seen that increasing the terrain height alone is not
sufficient to make tornadogenesis more probable as more tornadic supercells
were simulated with lower heights compared to moderate terrain heights.
| arxiv topic:physics.ao-ph |
arxiv_dataset-71011603.00679 | Fitting peculiar spectral profiles in He I 10830 \r{A} absorption
features
astro-ph.SR
The new generation of solar instruments provides better spectral, spatial,
and temporal resolution for a better understanding of the physical processes
that take place on the Sun. Multiple-component profiles are more commonly
observed with these instruments. Particularly, the He I 10830 \r{A} triplet
presents such peculiar spectral profiles, which give information on the
velocity and magnetic fine structure of the upper chromosphere. The purpose of
this investigation is to describe a technique to efficiently fit the two
blended components of the He I 10830 \r{A} triplet, which are commonly observed
when two atmospheric components are located within the same resolution element.
The observations used in this study were taken on 2015 April 17 with the very
fast spectroscopic mode of the GREGOR Infrared Spectrograph (GRIS) attached to
the 1.5-meter GREGOR solar telescope, located at the Observatorio del Teide,
Tenerife, Spain. We apply a double-Lorentzian fitting technique using
Levenberg-Marquardt least-squares minimization. This technique is very simple
and much faster than inversion codes. Line-of-sight Doppler velocities can be
inferred for a whole map of pixels within just a few minutes. Our results show
sub- and supersonic downflow velocities of up to 32 km/s for the fast component
in the vicinity of footpoints of filamentary structures. The slow component
presents velocities close to rest.
| arxiv topic:astro-ph.SR |
arxiv_dataset-71021603.00779 | Quantum critical magneto-transport at a continuous metal-insulator
transition
cond-mat.str-el
In contrast to the seminal weak localization prediction of a non-critical
Hall constant ($R_{H}$) at the Anderson metal-insulator transition (MIT),
$R_{H}$ in quite a few real disordered systems exhibits both, a strong
$T$-dependence and critical scaling near their MIT. Here, we investigate these
issues in detail within a non-perturbative "strong localization" regime using
cluster-dynamical mean field theory (CDMFT). We uncover $(i)$ clear and
unconventional quantum-critical scaling of the $\gamma$-function, finding that
$\gamma(g_{xy})\simeq$ log$(g_{xy})$ over a wide range spanning the continuous
MIT, very similar to that seen for the longitudinal conductivity, $(ii)$
strongly $T$-dependent and clear quantum critical scaling in both transverse
conductivity and $R_{H}$ at the MIT. We find that these surprising results are
in comprehensive and very good accord with signatures of a novel kind of
localization in disordered NbN near the MIT, providing substantial support for
our "strong" localization view.
| arxiv topic:cond-mat.str-el |
arxiv_dataset-71031603.00879 | Heavy neutrino impact on the triple Higgs coupling
hep-ph hep-ex
We present the first calculation of the one-loop corrections to the triple
Higgs coupling in the framework of a simplified 3+1 Dirac neutrino model, that
is three light neutrinos plus one heavy neutrino embedded in the Standard Model
(SM). The triple Higgs coupling is a key parameter of the scalar potential
triggering the electroweak symmetry-breaking mechanism in the SM. The impact of
the heavy neutrino can be as large as $+20\%$ to $+30\%$ for parameter points
allowed by the current experimental constraints depending on the tightness of
the perturbative bound. This can be probed at the high-luminosity LHC, at
future electron-positron colliders and at the Future Circular Collider in
hadron-hadron mode, an envisioned 100 TeV $pp$ machine. Our calculation, being
done in the mass basis, can be extended to any model using the neutrino portal.
In addition, the effects that we have calculated are expected to be enhanced if
additional heavy fermions with large Yukawa couplings are included, as in
low-scale seesaw mechanisms.
| arxiv topic:hep-ph hep-ex |
arxiv_dataset-71041603.00979 | Mean-Field Semantics for a Process Calculus for Spatially-Explicit
Ecological Models
cs.LO
We define a mean-field semantics for S-PALPS, a process calculus for
spatially-explicit, individual-based modeling of ecological systems. The new
semantics of S-PALPS allows an interpretation of the average behavior of a
system as a set of recurrence equations. Recurrence equations are a useful
approximation when dealing with a large number of individuals, as it is the
case in epidemiological studies. As a case study, we compute a set of
recurrence equations capturing the dynamics of an individual-based model of the
transmission of dengue in Bello (Antioquia), Colombia.
| arxiv topic:cs.LO |
arxiv_dataset-71051603.01079 | The Elliptic Function in Statistical Integrable Models
nlin.SI math-ph math.MP
We examine the group theoretical reason why various two dimensional
statistical integrable models, such as the Ising model, the chiral Potts model
and the Belavin model, becomes integrable. The symmetry of these integrable
models is SU(2) and the Boltzmann weight can be parametrized by the elliptic
function in many cases. In this paper, we examine the connection between the
SU(2) symmetry and the elliptic function in the statistical integrable models.
| arxiv topic:nlin.SI math-ph math.MP |
arxiv_dataset-71061603.01179 | Read networks and k-laminar graphs
cs.DM
In this paper we introduce k-laminar graphs a new class of graphs which
extends the idea of Asteroidal triple free graphs. Indeed a graph is k-laminar
if it admits a diametral path that is k-dominating. This bio-inspired class of
graphs was motivated by a biological application dealing with sequence
similarity networks of reads (called hereafter read networks for short). We
briefly develop the context of the biological application in which this graph
class appeared and then we consider the relationships of this new graph class
among known graph classes and then we study its recognition problem. For the
recognition of k-laminar graphs, we develop polynomial algorithms when k is
fixed. For k=1, our algorithm improves a Deogun and Krastch's algorithm (1999).
We finish by an NP-completeness result when k is unbounded.
| arxiv topic:cs.DM |
arxiv_dataset-71071603.01279 | Ideal Weyl semimetals in the chalcopyrites CuTlSe2, AgTlTe2, AuTlTe2 and
ZnPbAs2
cond-mat.mes-hall
Weyl semimetals are new states of matter which feature novel Fermi arcs and
exotic transport phenomena. Based on first-principles calculations, we report
that the chalcopyrites CuTlSe2, AgTlTe2, AuTlTe2 and ZnPbAs2 are ideal Weyl
semimetals, having largely separated Weyl points (~ 0.05/A) and uncovered Fermi
arcs that are amenable to experimental detections. We also construct a minimal
effective model to capture the low-energy physics of this class of Weyl
semimetals. Our discovery is a major step toward a perfect playground of
intriguing Weyl semimetals and potential applications for low-power and
high-speed electronics.
| arxiv topic:cond-mat.mes-hall |
arxiv_dataset-71081603.01379 | Geometric Hardy inequalities for the sub-elliptic Laplacian on convex
domains in the Heisenberg group
math.AP math.SP
We prove geometric $L^p$ versions of Hardy's inequality for the sub-elliptic
Laplacian on convex domains $\Omega$ in the Heisenberg group $\mathbb{H}^n$,
where convex is meant in the Euclidean sense. When $p=2$ and $\Omega$ is the
half-space given by $\langle \xi, \nu\rangle > d$ this generalizes an
inequality previously obtained by Luan and Yang. For such $p$ and $\Omega$ the
inequality is sharp and takes the form \begin{equation}
\int_\Omega |\nabla_{\mathbb{H}^n}u|^2 \, d\xi \geq \frac{1}{4}\int_{\Omega}
\sum_{i=1}^n\frac{\langle X_i(\xi), \nu\rangle^2+\langle Y_i(\xi),
\nu\rangle^2}{\textrm{dist}(\xi, \partial \Omega)^2}|u|^2\, d\xi,
\end{equation} where $\textrm{dist}(\, \cdot\,, \partial \Omega)$ denotes the
Euclidean distance from $\partial \Omega$.
| arxiv topic:math.AP math.SP |
arxiv_dataset-71091603.01479 | Pressure in Lema\^{i}tre-Tolman-Bondi solutions and cosmologies
gr-qc astro-ph.CO
Lema\^{i}tre-Tolman-Bondi (LTB) solutions have traditionally been confined to
systems with no pressure in which the gravity is due to massive dust, but the
solutions are little changed in form if, as in cosmology, the pressure is
uniform in space at each comoving time. This allows the equations of cosmology
to be deduced in a manner that more closely resembles classical mechanics. It
also gives some inhomogeneous solutions with growing condensations and black
holes. We give criteria by which the sizes of different closed models of the
universe can be compared and discuss conditions for self-closure of
inhomogeneous cosmologies with a $\Lambda$-term.
| arxiv topic:gr-qc astro-ph.CO |
arxiv_dataset-71101603.01579 | To Grow is Not Enough: Impact of Noise on Cell Environmental Response
and Fitness
q-bio.CB
Quantitative single cell measurements have shown that cell cycle duration
(the time between cell divisions) for diverse cell types is a noisy variable.
The underlying distribution is mean scalable with a universal shape for many
cell types in a variety of environments. Here we show through both experiment
and theory that increasing the amount of noise in the regulation of the cell
cycle negatively impacts the growth rate but positively correlates with
improved cellular response to fluctuating environments. Our findings suggest
that even non-cooperative cells in exponential growth phase do not optimize
fitness through growth rate alone, but also optimize adaptability to changing
conditions. In a manner similar to genetic evolution, increasing the noise in
biochemical processes correlates with improved response of the system to
environmental changes.
| arxiv topic:q-bio.CB |
arxiv_dataset-71111603.01679 | Reversibility of Linear Cellular Automata on Cayley Trees with Periodic
Boundary Condition
math.DS
While one-dimensional cellular automata have been well studied, there are
relatively few results about multidimensional cellular automata; the
investigation of cellular automata defined on Cayley trees constitutes an
intermediate class. This paper studies the reversibility of linear cellular
automata defined on Cayley trees with periodic boundary condition, where the
local rule is given by $f(x_0, x_1, \ldots, x_d) = b x_0 + c_1 x_1 + \cdots +
c_d x_d \pmod{m}$ for some integers $m, d \geq 2$. The reversibility problem
relates to solving a polynomial derived from a recurrence relation, and an
explicit formula is revealed; as an example, the complete criteria of the
reversibility of linear cellular automata defined on Cayley trees over
$\mathbb{Z}_2$, $\mathbb{Z}_3$, and some other specific case are addressed.
Further, this study achieves a possible approach for determining the
reversibility of multidimensional cellular automata, which is known as a
undecidable problem.
| arxiv topic:math.DS |
arxiv_dataset-71121603.01779 | Ion Dynamics at A Rippled Quasi-parallel Shock: 2-D Hybrid Simulations
physics.space-ph astro-ph.EP physics.plasm-ph
In this paper, two-dimensional (2-D) hybrid simulations are performed to
investigate ion dynamics at a rippled quasi-parallel shock. The results show
that the ripples around the shock front are inherent structures of a
quasi-parallel shock, and the reformation of the shock is not synchronous along
the surface of the shock front. By following the trajectories of the upstream
ions, we find that these ions behave differently when they interact with the
shock front at different positions along the shock surface. The upstream
particles are easier to transmit through the upper part of a ripple, and the
bulk velocity in the corresponding downstream is larger, where a high-speed jet
is formed. In the lower part of the ripple, the upstream particles tend to be
reflected by the shock. For the reflected ions by the shock, they may suffer
multiple stage acceleration when moving along the shock surface, or trapped
between the upstream waves and the shock front. At last, these ions may escape
to the further upstream or enter the downstream, therefore, the superthermal
ions can be found in both the upstream and downstream.
| arxiv topic:physics.space-ph astro-ph.EP physics.plasm-ph |
arxiv_dataset-71131603.01879 | Emergence time, curvature, space, causality, and complexity in encoding
a discrete impulse information process
nlin.AO
Interacting random field of probabilities links Kolmogorov law 0-1 and
Bayesian probabilities observing Markov diffusion process under Yes-No actions
of random impulse. These objective probabilities measure virtual probing
impulses processing the interactions in observable process. The impulse
observation increases each posteriori correlation reducing conditional entropy
measures from finite uncertainty up to certainty of real impulse. The reduced
entropy conveys probabilistic causality with time course and temporal memory in
collecting correlations, which interactive impulse innately cuts exposing
hidden process entropy. The natural cut of this entropy reveals information
hidden in the correlation connections. Inside the merging probing impulse
emerges reversible microprocess with yes-no conjugated entangled entropy,
curvature and logical complexity. Within the impulse time interval,
entanglement starts before its space is formed and ends with beginning the
space during reversible relative time interval being small part of impulse time
interval. Merging impulse curves and rotates the impulse interactive actions in
microprocess whose space interval measures this transitive movement.The cutting
entropy sequentially converting to information memorizes the probes logic in
Bit, participating in next probe conversions and encoding which memorizes
information causality. The complexity and mass appears after the space emerges
from the entanglement.The cognition assembles common units through the multiple
attraction and resonances at forming network (IN) of triplet hierarchy, which
accept only units that concentrates and recognizes each triplet IN node. The
ended triplet of hierarchical INs measures level of the observer intelligence.
The synthesized optimal process minimizes the observations time in Artificial
designed information Observer with intellectual searching logic.
| arxiv topic:nlin.AO |
arxiv_dataset-71141603.01979 | Two Tales of the World: Comparison of Widely Used World News Datasets
GDELT and EventRegistry
cs.DL cs.CY
In this work, we compare GDELT and Event Registry, which monitor news
articles worldwide and provide big data to researchers regarding scale, news
sources, and news geography. We found significant differences in scale and news
sources, but surprisingly, we observed high similarity in news geography
between the two datasets.
| arxiv topic:cs.DL cs.CY |
arxiv_dataset-71151603.02079 | Magnetic structures and magnetoelastic coupling of Fe-doped hexagonal
manganites LuMn1-xFexO3 (0 < x < 0.3)
cond-mat.str-el
We have studied the crystal and magnetic structures of Fe-doped hexagonal
manganites LuMn1-xFexO3 (x = 0, 0.1, 0.2, and 0.3) by using bulk magnetization
and neutron powder diffraction methods. The samples crystalize consistently in
a hexagonal structure and maintain the space group P63cm from 2 to 300 K. The
N\'eel temperature TN increases continuously with increasing Fe-doping. In
contrast to a single {\Gamma}4 representation in LuMnO3, the magnetic ground
state of the Fe-doped samples can only be described with a spin configuration
described by a mixture of {\Gamma}3 (P63'cm') and {\Gamma}4 (P63'c'm)
representations, whose contributions have been quantitatively estimated. The
drastic effect of Fe-doping is highlighted by composition-dependent spin
reorientations. A phase diagram of the entire composition series is proposed
based on the present results and those reported in literature. Our result
demonstrates the importance of tailoring compositions in increasing magnetic
transition temperatures of multiferroic systems.
| arxiv topic:cond-mat.str-el |
arxiv_dataset-71161603.02179 | Profinite groups with NIP theory and $p$-adic analytic groups
math.LO
We consider profinite groups as 2-sorted first order structures, with a group
sort, and a second sort which acts as an index set for a uniformly definable
basis of neighbourhoods of the identity. It is shown that if the basis consists
of {\em all} open subgroups, then the first order theory of such a structure is
NIP (that is, does not have the independence property) precisely if the group
has a normal subgroup of finite index which is a direct product of finitely
many compact $p$-adic analytic groups, for distinct primes $p$. In fact, the
condition NIP can here be weakened to NTP${}_2$. We also show that any NIP
profinite group, presented as a 2-sorted structure, has an open prosoluble
normal subgroup.
| arxiv topic:math.LO |
arxiv_dataset-71171603.02279 | ARPES study of the Kitaev Candidate $\alpha$-RuCl$_3$
cond-mat.str-el
$\alpha$-RuCl$_3$ has been hinted as a spin-orbital-assisted Mott insulator
in proximity to a Kitaev spin liquid state. Here we present ARPES measurements
on single crystal $\alpha$-RuCl$_3$ in both the pristine and electron-doped
states, and combine them with LDA+SOC+U calculations performed for the several
low-energy competing magnetically ordered states as well as the paramagnetic
state. A large Mott gap is found in the measured band structure of the pristine
compound that persists to more than 20 times beyond the magnetic ordering
temperature, though the paramagnetic calculation shows almost no gap. Upon
electron doping, spectral weight is transferred into the gap but the new states
still maintain a sizable gap from the Fermi edge. These findings are most
consistent with a Mott insulator with a somewhat exotic evolution out of the
Mott state with both temperature and doping, likely related to unusually strong
spin fluctuations.
| arxiv topic:cond-mat.str-el |
arxiv_dataset-71181603.02379 | An Easton like theorem in the presence of Shelah Cardinals
math.LO
We show that Shelah cardinals are preserved under the canonical $GCH$ forcing
notion. We also show that if $GCH$ holds and $F:REG\rightarrow CARD$ is an
Easton function which satisfies some weak properties, then there exists a
cofinality preserving generic extension of the universe which preserves Shelah
cardinals and satisfies $\forall \kappa\in REG,~ 2^{\kappa}=F(\kappa)$. This
gives a partial answer to a question asked by Cody [1] and independently by
Honzik [5]. We also prove an indestructibility result for Shelah cardinals.
| arxiv topic:math.LO |
arxiv_dataset-71191603.02479 | Evaluation of the performance of two state-transfer Hamiltonians in the
presence of static disorder
quant-ph
We analyse the performance of two quantum-state-transfer Hamiltonians in the
presence of diagonal and off-diagonal disorder, and in terms of different
measures. The first Hamiltonian pertains to a fully-engineered chain and the
second to a chain with modified boundary couplings. The task is to find which
Hamiltonian is the most robust to given levels of disorder and irrespective of
the input state. In this respect, it is shown that the performance of the two
protocols are approximately equivalent.
| arxiv topic:quant-ph |
arxiv_dataset-71201603.02579 | Avalanche boron fusion by laser picosecond block ignition with magnetic
trapping for clean and economic reactor
physics.plasm-ph
After the very long consideration of the ideal energy source by fusion of the
protons of light hydrogen with the boron isotope 11 (boron fusion HB11) the
very first two independent measurements of very high reaction gains by lasers
basically opens a fundamental breakthrough. The non-thermal plasma block
ignition with extremely high power laser pulses above petawatt of picosecond
duration in combination with up to ten kilotesla magnetic fields for trapping
has to be combined to use the measured high gains as proof of an avalanche
reaction for an environmentally clean, low cost and lasting energy source as
potential option against global warming. The unique HB11 avalanche reaction is
are now based on elastic collisions of helium nuclei (alpha particles) limited
only to a reactor for controlled fusion energy during a very short time within
a very small volume.
| arxiv topic:physics.plasm-ph |
arxiv_dataset-71211603.02679 | The Local Group: The Ultimate Deep Field
astro-ph.CO astro-ph.GA
Near-field cosmology -- using detailed observations of the Local Group and
its environs to study wide-ranging questions in galaxy formation and dark
matter physics -- has become a mature and rich field over the past decade.
There are lingering concerns, however, that the relatively small size of the
present-day Local Group ($\sim 2$ Mpc diameter) imposes insurmountable
sample-variance uncertainties, limiting its broader utility. We consider the
region spanned by the Local Group's progenitors at earlier times and show that
it reaches $3' \approx 7$ co-moving Mpc in linear size (a volume of $\approx
350\,{\rm Mpc}^3$) at $z=7$. This size at early cosmic epochs is large enough
to be representative in terms of the matter density and counts of dark matter
halos with $M_{\rm vir}(z=7) \lesssim 2\times 10^{9}\,M_{\odot}$. The Local
Group's stellar fossil record traces the cosmic evolution of galaxies with
$10^{3} \lesssim M_{\star}(z=0) / M_{\odot} \lesssim 10^{9}$ (reaching
$M_{1500} > -9$ at $z\sim7$) over a region that is comparable to or larger than
the Hubble Ultra-Deep Field (HUDF) for the entire history of the Universe. It
is highly complementary to the HUDF, as it probes much fainter galaxies but
does not contain the intrinsically rarer, brighter sources that are detectable
in the HUDF. Archaeological studies in the Local Group also provide the ability
to trace the evolution of individual galaxies across time as opposed to
evaluating statistical connections between temporally distinct populations. In
the JWST era, resolved stellar populations will probe regions larger than the
HUDF and any deep JWST fields, further enhancing the value of near-field
cosmology.
| arxiv topic:astro-ph.CO astro-ph.GA |
arxiv_dataset-71221603.02779 | Spherical averages in the space of marked lattices
math.DS math-ph math.MP math.PR
A marked lattice is a $d$-dimensional Euclidean lattice, where each lattice
point is assigned a mark via a given random field on ${\mathbb Z}^d$. We prove
that, if the field is strongly mixing with a faster-than-logarithmic rate, then
for every given lattice and almost every marking, large spheres become
equidistributed in the space of marked lattices. A key aspect of our study is
that the space of marked lattices is not a homogeneous space, but rather a
non-trivial fiber bundle over such a space. As an application, we prove that
the free path length in a crystal with random defects has a limiting
distribution in the Boltzmann-Grad limit.
| arxiv topic:math.DS math-ph math.MP math.PR |
arxiv_dataset-71231603.02879 | Theoretical modeling of critical temperature increase in metamaterial
superconductors
cond-mat.supr-con physics.optics
Recent experiments have demonstrated that the metamaterial approach is
capable of drastic increase of the critical temperature Tc of epsilon near zero
(ENZ) metamaterial superconductors. For example, tripling of the critical
temperature has been observed in Al-Al2O3 ENZ core-shell metamaterials. Here,
we perform theoretical modelling of Tc increase in metamaterial superconductors
based on the Maxwell-Garnett approximation of their dielectric response
function. Good agreement is demonstrated between theoretical modelling and
experimental results in both aluminium and tin-based metamaterials. Taking
advantage of the demonstrated success of this model, the critical temperature
of hypothetic niobium, MgB2 and H2S-based metamaterial superconductors is
evaluated. The MgB2-based metamaterial superconductors are projected to reach
the liquid nitrogen temperature range. In the case of an H2S-based metamaterial
Tc appears to reach ~250K.
| arxiv topic:cond-mat.supr-con physics.optics |
arxiv_dataset-71241603.02979 | Observation of Quantum Phase Transitions with Parity-Symmetry Breaking
and Hysteresis
cond-mat.quant-gas physics.atom-ph quant-ph
Symmetry-breaking quantum phase transitions play a key role in several
condensed matter, cosmology and nuclear physics theoretical models. Its
observation in real systems is often hampered by finite temperatures and
limited control of the system parameters. In this work we report for the first
time the experimental observation of the full quantum phase diagram across a
transition where the spatial parity symmetry is broken. Our system is made of
an ultra-cold gas with tunable attractive interactions trapped in a spatially
symmetric double-well potential. At a critical value of the interaction
strength, we observe a continuous quantum phase transition where the gas
spontaneously localizes in one well or the other, thus breaking the underlying
symmetry of the system. Furthermore, we show the robustness of the asymmetric
state against controlled energy mismatch between the two wells. This is the
result of hysteresis associated with an additional discontinuous quantum phase
transition that we fully characterize. Our results pave the way to the study of
quantum critical phenomena at finite temperature, the investigation of
macroscopic quantum tunneling of the order parameter in the hysteretic regime
and the production of strongly quantum entangled states at critical points.
| arxiv topic:cond-mat.quant-gas physics.atom-ph quant-ph |
arxiv_dataset-71251603.03079 | Testing boundaries of applicability of quantum probabilistic formalism
to modeling of cognition
q-bio.NC math.PR quant-ph
Recently the mathematical formalism of quantum mechanics, especially methods
of quantum probability theory, started to be widely used in a variety of
applications outside of physics, e.g., cognition and psychology as well as
economy and finances. To distinguish such models from genuine quantum physical
models, they often called quantum-like (although often people simply speak
about, e.g., "quantum cognition"). These novel applications generate a number
of foundational questions. Nowadays we can speak about a new science -
foundations of quantum-like modeling. At the first stage this science was
mainly about comparison of classical and quantum models, mainly in the
probabilistic setting. It was found that statistical data from cognitive
psychology violate some basic constraints posed on data by classical
probability theory (Kolmogorov, 1933); in particular, the constraints given by
the formula of total probability and Bell's type inequalities. Recently another
question attracted some attention. In spite of real success in applications,
there are no reason to believe that the quantum probability would cover
completely all problems of, e.g., cognition. May be more general probability
models have to be explored. A similar problem attracted a lot of attention in
foundations of quantum physics culminating in a series of experiments to check
Sorkin's equality for the triple-slit experiment by Weihs' group. In this note
we present a similar test in the cognitive experimental setting. Performance of
this test would either give further confirmation of the adequacy of the quantum
probability model to cognitive applications or rejection of the conventional
quantum model. Thus this note opens the door for a series of exciting
experimental tests for the quantum-like model of cognition.
| arxiv topic:q-bio.NC math.PR quant-ph |
arxiv_dataset-71261603.03179 | Ergodicity and propagation of chaos for mean field kinetic particles
math.PR
The trend to equilibrium in large time is studied for a large particle system
associated to a Vlasov-Fokker-Planck equation in the presence of a convex
external potential, without smallness restriction on the interaction. From this
are derived uniform in time propagation of chaos estimates, which themselves
yield in turn an exponentially fast convergence for the semi-linear equation
itself. The approach is quantitative.
| arxiv topic:math.PR |
arxiv_dataset-71271603.03279 | Transport and deceleration of fusion products in microturbulence
physics.plasm-ph
The velocity-space distribution of alpha particles born in fusion devices is
subject to modification at moderate energies due to turbulent transport.
Therefore, one must calculate the evolution of an equilibrium distribution
whose functional form is not known \emph{a priori}. Using a novel technique,
applicable to any trace impurity, we have made this calculation not only
possible, but particularly efficient. We demonstrate a microturbulence-induced
departure from the local slowing-down distribution, an inversion of the energy
distribution, and associated modifications to the alpha heating and pressure
profiles in an ITER-like scenario.
| arxiv topic:physics.plasm-ph |
arxiv_dataset-71281603.03379 | Radiation reaction on a Brownian scalar electron in high-intensity
fields
math-ph hep-th math.MP physics.plasm-ph
Radiation reaction against a relativistic electron is of critical importance
since the experiment to check this "quantumness" becomes possible soon with an
extremely high-intensity laser beam. However, there is a fundamental
mathematical quest to apply any laser profiles to laser focusing and
superposition beyond the Furry picture of its usual method by a plane wave. To
give the apparent meaning of $q(\chi)$ the quantumness factor with respect to a
radiation process is absent. Thus for resolving the above questions, we propose
stochastic quantization of the classical radiation reaction model for any laser
field profiles, via the construction of the relativistic Brownian kinematics
with the dynamics of a scalar electron and the Maxwell equation with a current
by a Brownian quanta. This is the first proposal of the coupling system between
a relativistic Brownian quanta and fields in Nelson's stochastic quantization.
Therefore, we can derive the radiation field by its Maxwell equation, too. This
provides us the fact that $q(\chi)$ produced by QED is regarded as
$\mathscr{P}(\varOmega_{\tau}^{\mathrm{ave}})$ of an existence probability such
that a scalar electron stay on its average trajectory.
| arxiv topic:math-ph hep-th math.MP physics.plasm-ph |
arxiv_dataset-71291603.03479 | Free energy of ligand-receptor systems forming multimeric complexes
cond-mat.stat-mech cond-mat.soft physics.bio-ph
Ligand-receptor interactions are ubiquitous in biology and have become
popular in materials in view of their applications to programmable
self-assembly. Although, complex functionalities often emerge from the
simultaneous interaction of more than just two linker molecules, state of art
theoretical frameworks enable the calculation of the free energy only in
systems featuring one-to-one ligand/receptor binding. In this communication we
derive a general formula to calculate the free energy of a system featuring
simultaneous direct interaction between an arbitrary number of linkers. To
exemplify the potential and generality of our approach we apply it to the
systems recently introduced by Parolini et al. [ACS Nano 10, 2392 (2016)] and
Halverson et al. [J. Chem. Phys. 144, 094903 (2016)], both featuring
functioanlized Brownian particles interacting via three-linker complexes.
| arxiv topic:cond-mat.stat-mech cond-mat.soft physics.bio-ph |
arxiv_dataset-71301603.03579 | Entanglement entropy in a periodically driven quantum Ising chain
cond-mat.stat-mech quant-ph
We numerically study the dynamics of entanglement entropy, induced by an
oscillating time periodic driving of the transverse field, h(t), of a
one-dimensional quantum Ising chain. We consider several realizations of h(t),
and we find a number of results in analogy with entanglement entropy dynamics
induced by a sudden quantum quench. After short-time relaxation, the dynamics
of entanglement entropy synchronises with h(t), displaying an oscillatory
behaviour at the frequency of the driving. Synchronisation in the dynamics of
entanglement entropy, is spoiled by the appearance of quasi-revivals which fade
out in the thermodynamic limit, and which we interpret using a quasi-particle
picture adapted to periodic drivings. Taking the time-average of the
entanglement entropy in the synchronised regime, we find that it obeys a volume
law scaling with the subsystem's size. Such result is reminiscent of a thermal
state or of a Generalised Gibbs ensemble of a quenched Ising chain, although
the system does not heat up towards infinite temperature as a consequence of
the integrability of the model.
| arxiv topic:cond-mat.stat-mech quant-ph |
arxiv_dataset-71311603.03679 | Simultaneous chiral symmetry restoration and deconfinement -
Consequences for the QCD phase diagram
nucl-th astro-ph.HE hep-ph
For studies of quark matter in astrophysical scenarios the thermodynamic bag
model (tdBag) is commonly employed. Although successful, it does not account
for dynamical chiral symmetry breaking (D$\chi$SB) and repulsions due to the
vector interaction which is crucial to explain recent observations of massive,
two solar mass neutron stars. In Kl\"ahn & Fischer (2015) we developed the
novel vBag quark matter model which takes these effects into account. This
article extends vBag to finite temperatures and isospin asymmetry. Another
particular feature of vBag is the determination of the deconfinement bag
constant $B_{\rm dc}$ from a given hadronic equation of state (EoS) in order to
ensure that chiral and deconfinement transitions coincide. We discuss
consequences of this novel approach for the phase transition construction, the
phase diagram, and implications for protoneutron stars.
| arxiv topic:nucl-th astro-ph.HE hep-ph |
arxiv_dataset-71321603.03779 | Is there really a $W \to \tau\nu$ puzzle?
hep-ph hep-ex
According to the Particle Data Group, the measurements of ${\cal B}(W^+ \to
\tau^+ \nu_\tau)$ and ${\cal B}(W^+ \to \ell^+ \nu_\ell)$ ($\ell = e,\mu$)
disagree with one another at the $2.3\sigma$ level. In this paper, we search
for a new-physics (NP) explanation of this $W \to \tau\nu$ puzzle. We consider
two NP scenarios: (i) the $W$ mixes with a $W'$ boson that couples
preferentially to the third generation, (ii) $\tau_{L,R}$ and $\nu_{\tau L}$
mix with isospin-triplet leptons. Unfortunately, once other experimental
constraints are taken into account, neither scenario can explain the above
experimental result. Our conclusion is that the $W \to \tau\nu$ puzzle is
almost certainly just a statistical fluctuation.
| arxiv topic:hep-ph hep-ex |
arxiv_dataset-71331603.03879 | Dark Energy: The Shadowy Reflection of Dark Matter?
astro-ph.CO
In this article, we review a series of recent theoretical results regarding a
conventional approach to the dark energy (DE) concept. This approach is
distinguished among others for its simplicity and its physical relevance. By
compromising General Relativity (GR) and Thermodynamics at cosmological scale,
we end up with a model without DE. Instead, the Universe we are proposing is
filled with a perfect fluid of self-interacting dark matter (DM), the volume
elements of which perform hydrodynamic flows. To the best of our knowledge, it
is the first time in a cosmological framework that the energy of the cosmic
fluid internal motions is also taken into account as a source of the universal
gravitational field. As we demonstrate, this form of energy may compensate for
the DE needed to compromise spatial flatness, while, depending on the
particular type of thermodynamic processes occurring in the interior of the DM
fluid (isothermal or polytropic), the Universe depicts itself as either
decelerating or accelerating (respectively). In both cases, there is no
disagreement between observations and the theoretical prediction of the distant
supernovae (SNe) Type Ia distribution. In fact, the cosmological model with
matter content in the form of a thermodynamically-involved DM fluid not only
interprets the observational data associated with the recent history of
Universe expansion, but also confronts successfully with every major
cosmological issue (such as the age and the coincidence problems). In this way,
depending on the type of thermodynamic processes in it, such a model may serve
either for a conventional DE cosmology or for a viable alternative one.
| arxiv topic:astro-ph.CO |
arxiv_dataset-71341603.03979 | A sub-1-volt analog metal oxide memristive-based synaptic device for
energy-efficient spike-based computing systems
cond-mat.mes-hall
Nanoscale metal oxide memristors have potential in the development of
brain-inspired computing systems that are scalable and efficient1-3. In such
systems, memristors represent the native electronic analogues of the biological
synapses. However, the characteristics of the existing memristors do not fully
support the key requirements of synaptic connections: high density, adjustable
weight, and low energy operation. Here we show a bilayer memristor that is
forming-free, low-voltage (~|0.8V|), energy-efficient (full On/Off switching at
~2pJ), and reliable. Furthermore, pulse measurements reveal the analog nature
of the memristive device, that is it can be directly programmed to intermediate
resistance states. Leveraging this finding, we demonstrate
spike-timing-dependent plasticity (STDP), a spike-based Hebbian learning rule4.
In those experiments, the memristor exhibits a marked change in the normalized
synaptic strength (>30 times) when the pre- and post-synaptic neural spikes
overlap. This demonstration is an important step towards the physical
construction of high density and high connectivity neural networks.
| arxiv topic:cond-mat.mes-hall |
arxiv_dataset-71351603.04079 | Indoor 5G 3GPP-like Channel Models for Office and Shopping Mall
Environments
cs.IT math.IT
Future mobile communications systems are likely to be very different to those
of today with new service innovations driven by increasing data traffic demand,
increasing processing power of smart devices and new innovative applications.
To meet these service demands the telecommunications industry is converging on
a common set of 5G requirements which includes network speeds as high as 10
Gbps, cell edge rate greater than 100 Mbps, and latency of less than 1 msec. To
reach these 5G requirements the industry is looking at new spectrum bands in
the range up to 100 GHz where there is spectrum availability for wide bandwidth
channels. For the development of new 5G systems to operate in bands up to 100
GHz there is a need for accurate radio propagation models which are not
addressed by existing channel models developed for bands below 6 GHz. This
paper presents a preliminary overview of the 5G channel models for bands up to
100 GHz in indoor offices and shopping malls, derived from extensive
measurements across a multitude of bands. These studies have found some
extensibility of the existing 3GPP models to the higher frequency bands up to
100 GHz. The measurements indicate that the smaller wavelengths introduce an
increased sensitivity of the propagation models to the scale of the environment
and show some frequency dependence of the path loss as well as increased
occurrence of blockage. Further, the penetration loss is highly dependent on
the material and tends to increase with frequency. The small-scale
characteristics of the channel such as delay spread and angular spread and the
multipath richness is somewhat similar over the frequency range, which is
encouraging for extending the existing 3GPP models to the wider frequency
range. Further work will be carried out to complete these models, but this
paper presents the first steps for an initial basis for the model development.
| arxiv topic:cs.IT math.IT |
arxiv_dataset-71361603.04179 | Performance Analysis of Source Image Estimators in Blind Source
Separation
cs.SD cs.IT cs.SY math.IT
Blind methods often separate or identify signals or signal subspaces up to an
unknown scaling factor. Sometimes it is necessary to cope with the scaling
ambiguity, which can be done through reconstructing signals as they are
received by sensors, because scales of the sensor responses (images) have known
physical interpretations. In this paper, we analyze two approaches that are
widely used for computing the sensor responses, especially, in Frequency-Domain
Independent Component Analysis. One approach is the least-squares projection,
while the other one assumes a regular mixing matrix and computes its inverse.
Both estimators are invariant to the unknown scaling. Although frequently used,
their differences were not studied yet. A goal of this work is to fill this
gap. The estimators are compared through a theoretical study, perturbation
analysis and simulations. We point to the fact that the estimators are
equivalent when the separated signal subspaces are orthogonal, and vice versa.
Two applications are shown, one of which demonstrates a case where the
estimators yield substantially different results.
| arxiv topic:cs.SD cs.IT cs.SY math.IT |
arxiv_dataset-71371603.04279 | Non-symmetric polarization
math.FA
Let $P$ be an $m$-homogeneous polynomial in $n$-complex variables $x_1,
\dotsc, x_n$. Clearly, $P$ has a unique representation in the form
\begin{equation*} P(x)= \sum_{1 \leq j_1 \leq \dotsc \leq j_m \leq n} c_{(j_1,
\dotsc, j_m)} \, x_{j_1} \dotsb x_{j_m} \,, \end{equation*} and the $m$"~form
\begin{equation*} L_P(x^{(1)}, \dotsc, x^{(m)})= \sum_{1 \leq j_1 \leq \dotsc
\leq j_m \leq n} c_{(j_1, \dotsc, j_m)} \, x^{(1)}_{j_1} \dotsb x^{(m)}_{j_m}
\end{equation*} satisfies $L_P(x,\dotsc, x) = P(x)$ for every
$x\in\mathbb{C}^n$. We show that, although $L_P$ in general is non-symmetric,
for a large class of reasonable norms $ \lVert \cdot \rVert $ on $\mathbb{C}^n$
the norm of $L_P$ on $(\mathbb{C}^n, \lVert \cdot \rVert )^m$ up to a
logarithmic term $(c \log n)^{m^2}$ can be estimated by the norm of $P$ on $
(\mathbb{C}^n, \lVert \cdot \rVert )$; here $c \ge 1$ denotes a universal
constant. Moreover, for the $\ell_p$"~norms $ \lVert \cdot \rVert_p$, $1 \leq p
< 2$ the logarithmic term in the number $n$ of variables is even superfluous.
| arxiv topic:math.FA |
arxiv_dataset-71381603.04379 | On Data Dependence in Distributed Stochastic Optimization
math.OC
We study a distributed consensus-based stochastic gradient descent (SGD)
algorithm and show that the rate of convergence involves the spectral
properties of two matrices: the standard spectral gap of a weight matrix from
the network topology and a new term depending on the spectral norm of the
sample covariance matrix of the data. This data-dependent convergence rate
shows that distributed SGD algorithms perform better on datasets with small
spectral norm. Our analysis method also allows us to find data-dependent
convergence rates as we limit the amount of communication. Spreading a fixed
amount of data across more nodes slows convergence; for asymptotically growing
data sets we show that adding more machines can help when minimizing
twice-differentiable losses.
| arxiv topic:math.OC |
arxiv_dataset-71391603.04479 | Confronting dark matter with the diphoton excess from a parent resonance
decay
hep-ph
A diphoton excess with an invariant mass of about 750 GeV has been recently
reported by both ATLAS and CMS experiments at LHC. While the simplest
interpretation requires the resonant production of a 750 GeV (pseudo)scalar,
here we consider an alternative setup, with an additional heavy parent particle
which decays into a pair of 750 GeV resonances. This configuration improves the
agreement between the 8 TeV and 13 TeV data. Moreover, we include a dark matter
candidate in the form of a Majorana fermion which interacts through the 750 GeV
portal. The invisible decays of the light resonance help to suppress additional
decay channels into Standard Model particles in association with the diphoton
signal. We realise our hierarchical framework in the context of an effective
theory, and we analyse the diphoton signal as well as the consistency with
other LHC searches. We finally address the interplay of the LHC results with
the dark matter phenomenology, namely the compatibility with the relic density
abundance and the indirect detection bounds.
| arxiv topic:hep-ph |
arxiv_dataset-71401603.04579 | Impurity scattering and Friedel oscillations in mono-layer black
phosphorus
cond-mat.mes-hall
We study the effect of impurity scattering effect in black phosphorurene (BP)
in this work. For single impurity, we calculate impurity induced local density
of states (LDOS) in momentum space numerically based on tight-binding
Hamiltonian. In real space, we calculate LDOS and Friedel oscillation
analytically. LDOS shows strong anisotropy in BP. Many impurities in BP are
investigated using $T$-matrix approximation when the density is low. Midgap
states appear in band gap with peaks in DOS. The peaks of midgap states are
dependent on impurity potential. For finite positive potential, the impurity
tends to bind negative charge carriers and vise versa. The infinite impurity
potential problem is related to chiral symmetry in BP.
| arxiv topic:cond-mat.mes-hall |
arxiv_dataset-71411603.04679 | Photon bremsstrahlung from quark jet via transverse and longitudinal
scatterings: single versus multiple scatterings
hep-ph nucl-ex nucl-th
We study the production of jet-bremsstrahlung photons through the scattering
with the constituents of a dense nuclear matter within the framework of
deep-inelastic scattering off a large nucleus. Applying a gradient expansion up
to the second order for the exchanged three-dimensional momentum between jet
and medium, we derive the single photon bremsstrahlung spectrum with the
inclusion of the contributions from the transverse broadening as well as the
longitudinal drag and diffusion of the hard parton's momentum. We also compare
the medium-induced photon radiation spectra for single scattering and from the
resummation of multiple scatterings. It is found that the coupling between
different scatterings can give additional contribution to medium-induced photon
radiation, while for small momentum exchange, the leading contribution from the
drag and diffusions to the photon emission spectra remain the same for single
and multiple scatterings.
| arxiv topic:hep-ph nucl-ex nucl-th |
arxiv_dataset-71421603.04779 | Revisiting Batch Normalization For Practical Domain Adaptation
cs.CV cs.LG
Deep neural networks (DNN) have shown unprecedented success in various
computer vision applications such as image classification and object detection.
However, it is still a common annoyance during the training phase, that one has
to prepare at least thousands of labeled images to fine-tune a network to a
specific domain. Recent study (Tommasi et al. 2015) shows that a DNN has strong
dependency towards the training dataset, and the learned features cannot be
easily transferred to a different but relevant task without fine-tuning. In
this paper, we propose a simple yet powerful remedy, called Adaptive Batch
Normalization (AdaBN) to increase the generalization ability of a DNN. By
modulating the statistics in all Batch Normalization layers across the network,
our approach achieves deep adaptation effect for domain adaptation tasks. In
contrary to other deep learning domain adaptation methods, our method does not
require additional components, and is parameter-free. It archives
state-of-the-art performance despite its surprising simplicity. Furthermore, we
demonstrate that our method is complementary with other existing methods.
Combining AdaBN with existing domain adaptation treatments may further improve
model performance.
| arxiv topic:cs.CV cs.LG |
arxiv_dataset-71431603.04879 | On self-similar finite $p$-groups
math.GR
In this paper, we address the following question: when is a finite $p$-group
$G$ self-similar, i.e. when can $G$ be faithfully represented as a self-similar
group of automorphisms of the $p$-adic tree? We show that, if $G$ is a
self-similar finite $p$-group of rank $r$, then its order is bounded by a
function of $p$ and $r$. This applies in particular to finite $p$-groups of a
given coclass. In the particular case of groups of maximal class, that is, of
coclass $1$, we can fully answer the question above: a $p$-group of maximal
class $G$ is self-similar if and only if it contains an elementary abelian
maximal subgroup over which $G$ splits. Furthermore, in that case the order of
$G$ is at most $p^p+1$, and this bound is sharp.
| arxiv topic:math.GR |
arxiv_dataset-71441603.04979 | Guitar Solos as Networks
cs.SD
This paper presents an approach to model melodies (and music pieces in
general) as networks. Notes of a melody can be seen as nodes of a network that
are connected whenever these are played in sequence. This creates a directed
graph. By using complex network theory, it is possible to extract some main
metrics, typical of networks, that characterize the piece. Using this
framework, we provide an analysis on a set of guitar solos performed by main
musicians. The results of this study indicate that this model can have an
impact on multimedia applications such as music classification, identification,
and automatic music generation.
| arxiv topic:cs.SD |
arxiv_dataset-71451603.05079 | Classical communication cost of quantum steering
quant-ph
Quantum steering is observed when performing appropriate local measurements
on an entangled state. Here we discuss the possibility of simulating
classically this effect, using classical communication instead of entanglement.
We show that infinite communication is necessary for exactly simulating
steering for any pure entangled state, as well as for a class of mixed
entangled states. Moreover, we discuss the communication cost of steering for
general entangled states, as well as approximate simulation. Our findings
reveal striking differences between Bell nonlocality and steering, and provide
a natural way of measuring the strength of the latter.
| arxiv topic:quant-ph |
arxiv_dataset-71461603.05179 | Gaps, rings, and non-axisymmetric structures in protoplanetary disks -
Emission from large grains
astro-ph.EP
Dust grains with sizes around (sub)mm are expected to couple only weakly to
the gas motion in regions beyond 10 au of circumstellar disks. In this work, we
investigate the influence of the spatial distribution of such grains on the
(sub)mm appearance of magnetized protoplanetary disks. We perform non-ideal
global 3D magneto-hydrodynamic stratified disk simulations including particles
of different sizes (50 micron to 1 cm), using a Lagrangian particle solver. We
calculate the spatial dust temperature distribution, including the dynamically
coupled submicron-sized dust grains, and derive ideal continuum re-emission
maps of the disk through radiative transfer simulations. Finally, we
investigate the feasibility to observe specific structures in the thermal
re-emission maps with the Atacama Large Millimeter/submillimeter Array (ALMA).
The pressure bump close to the outer edge of the dead-zone leads to particle
trapping in ring structures. More specifically, vortices in the disk
concentrate the dust and create an inhomogeneous distribution of the solid
material in the azimuthal direction. The large-scale disk perturbations are
preserved in the (sub)mm re-emission maps. The observable structures are very
similar to those expected to result from planet-disk interaction. The larger
dust particles increase the brightness contrast between gap and ring
structures. We find that rings, gaps and the dust accumulation in the vortex
could be traced with ALMA down to a scale of a few astronomical units in
circumstellar disks located in nearby star-forming regions. Finally, we present
a brief comparison of these structures with those recently found with ALMA in
the young circumstellar disks of HL Tau and Oph IRS 48.
| arxiv topic:astro-ph.EP |
arxiv_dataset-71471603.05279 | XNOR-Net: ImageNet Classification Using Binary Convolutional Neural
Networks
cs.CV
We propose two efficient approximations to standard convolutional neural
networks: Binary-Weight-Networks and XNOR-Networks. In Binary-Weight-Networks,
the filters are approximated with binary values resulting in 32x memory saving.
In XNOR-Networks, both the filters and the input to convolutional layers are
binary. XNOR-Networks approximate convolutions using primarily binary
operations. This results in 58x faster convolutional operations and 32x memory
savings. XNOR-Nets offer the possibility of running state-of-the-art networks
on CPUs (rather than GPUs) in real-time. Our binary networks are simple,
accurate, efficient, and work on challenging visual tasks. We evaluate our
approach on the ImageNet classification task. The classification accuracy with
a Binary-Weight-Network version of AlexNet is only 2.9% less than the
full-precision AlexNet (in top-1 measure). We compare our method with recent
network binarization methods, BinaryConnect and BinaryNets, and outperform
these methods by large margins on ImageNet, more than 16% in top-1 accuracy.
| arxiv topic:cs.CV |
arxiv_dataset-71481603.05379 | Hardy spaces on metric measure spaces with generalized sub-gaussian heat
kernel estimates
math.CA
Hardy space theory has been studied on manifolds or metric measure spaces
equipped with either Gaussian or sub-Gaussian heat kernel behaviour. However,
there are natural examples where one finds a mix of both behaviour (locally
Gaussian and at infinity sub-Gaussian) in which case the previous theory
doesn't apply. Still we define molecular and square function Hardy spaces using
appropriate scaling, and we show that they agree with Lebesgue spaces in some
range. Besides, counterexamples are given in this setting that the $H^p$ space
corresponding to Gaussian estimates may not coincide with $L ^p$. As a
motivation for this theory, we show that the Riesz transform maps our Hardy
space $H^1$ into $L^1$ .
| arxiv topic:math.CA |
arxiv_dataset-71491603.05479 | The VLT LEGA-C Spectroscopic Survey: The Physics of Galaxies at a
Lookback Time of 7 Gyr
astro-ph.GA
The Large Early Galaxy Census (LEGA-C) is a Public Spectroscopic Survey of
$\sim3200$ $K$-band selected galaxies at redshifts $z=0.6-1.0$ with stellar
masses M_star > 1e10M_sun, conducted with VIMOS on ESO's Very Large Telescope.
The survey is embedded in the COSMOS field ($R.A. = 10h00$; $Dec.=+2\deg$). The
20-hour long integrations produce high-$S/N$ continuum spectra that reveal
ages, metallicities and velocity dispersions of the stellar populations.
LEGA-C's unique combination of sample size and depth will enable us for the
first time to map the stellar content at large look-back time, across galaxies
of different types and star-formation activity. Observations started in
December 2014 and are planned to be completed by mid 2018, with early data
releases of the spectra and value-added products. In this paper we present the
science case, the observing strategy, an overview of the data reduction process
and data products, and a first look at the relationship between galaxy
structure and spectral properties, as it existed 7 Gyr ago.
| arxiv topic:astro-ph.GA |
arxiv_dataset-71501603.05579 | Convergence of a Newton algorithm for semi-discrete optimal transport
math.NA cs.CG math.AP
Many problems in geometric optics or convex geometry can be recast as optimal
transport problems: this includes the far-field reflector problem, Alexandrov's
curvature prescription problem, etc. A popular way to solve these problems
numerically is to assume that the source probability measure is absolutely
continuous while the target measure is finitely supported. We refer to this
setting as semi-discrete optimal transport. Among the several algorithms
proposed to solve semi-discrete optimal transport problems, one currently needs
to choose between algorithms that are slow but come with a convergence speed
analysis (e.g. Oliker-Prussner) or algorithms that are much faster in practice
but which come with no convergence guarantees Algorithms of the first kind rely
on coordinate-wise increments and the number of iterations required to reach
the solution up to an error of $\epsilon$ is of order $N^3/\epsilon$, where $N$
is the number of Dirac masses in the target measure. On the other hand,
algorithms of the second kind typically rely on the formulation of the
semi-discrete optimal transport problem as an unconstrained convex optimization
problem which is solved using a Newton or quasi-Newton method.
The purpose of this article is to bridge this gap between theory and practice
by introducing a damped Newton's algorithm which is experimentally efficient
and by proving the global convergence of this algorithm with optimal rates. The
main assumptions is that the cost function satisfies a condition that appears
in the regularity theory for optimal transport (the Ma-Trudinger-Wang
condition) and that the support of the source density is connected in a
quantitative way (it must satisfy a weighted Poincar\'e-Wirtinger inequality).
| arxiv topic:math.NA cs.CG math.AP |
arxiv_dataset-71511603.05679 | Classification of
$(\widetilde{Sp}(n,\mathbb{R})\times\widetilde{Sp}(1,\mathbb{R}))$-Manifolds
math.DG
Let $M$ be an analytic complete finite volume pseudo-Riemannian manifold and
$\widetilde{Sp}(n,\mathbb{R})\times\widetilde{Sp}(1,\mathbb{R})$ a connected
semisimple Lie group such that its Lie algebra is
$\mathfrak{sp}(n,\mathbb{R})\oplus\mathfrak{sp}(1,\mathbb{R})$. We characterize
the structure of the manifold $M$ assuming that the Lie group
$\widetilde{Sp}(n,\mathbb{R})\times\widetilde{Sp}(1,\mathbb{R})$ acts
isometrically on $M$ and that its dimension satisfies
$3+n(2n+1)<\dim(M)\leq(n+1)(2n+3)$.
| arxiv topic:math.DG |
arxiv_dataset-71521603.05779 | Voltage-Controlled Low-Energy Switching of Nanomagnets through
Ruderman-Kittel-Kasuya-Yosida Interactions for Magnetoelectric Device
Applications
cond-mat.mes-hall
In this letter, we consider through simulation Ruderman-Kittel-Kasuya-Yosida
(RKKY) interactions between nanomagnets sitting on a conductive surface, and
voltage-controlled gating thereof for low-energy switching of nanomagnets for
possible memory and nonvolatile logic applications. For specificity, we
consider nanomagnets with perpendicular anisotropy on a three-dimensional
topological insulator. We model the possibility and dynamics of RKKY-based
switching of one nanomagnet by coupling to one or more nanomagnets of set
orientation. Applications for both memory and nonvolatile logic are considered,
with follower, inverter and majority gate functionality shown. Sub-attojoule
switching energies, far below conventional spin transfer torque (STT)-based
memories and even below CMOS logic appear possible. Switching times on the
order of a few nanoseconds, comparable to times for STT switching, are
estimated for ferromagnetic nanomagnets.
| arxiv topic:cond-mat.mes-hall |
arxiv_dataset-71531603.05879 | Symmetry breaking in spin spirals and skyrmions by in-plane and canted
magnetic fields
cond-mat.mes-hall
The influence of in-plane and canted magnetic fields on spin spirals and
skyrmions in atomic bilayer islands of palladium and iron on an Ir(111)
substrate is investigated by scanning tunnelling microscopy at low
temperatures. It is shown that the spin spiral propagation direction is
determined by the island's border which can be explained by equilibrium state
calculations on a triangular lattice. By application of in-plane fields, the
spin spiral reorientates its propagation direction and becomes distorted,
thereby allowing a proof for its cycloidal nature. Furthermore, it is
demonstrated that the skyrmions' shape is distorted in canted fields which
allows to determine the sense of magnetisation rotation as enforced by the
interfacial Dzyaloshinskii-Moriya interaction.
| arxiv topic:cond-mat.mes-hall |
arxiv_dataset-71541603.05979 | The effects of short-lived radionuclides and porosity on the early
thermo-mechanical evolution of planetesimals
astro-ph.EP physics.geo-ph
The thermal history and internal structure of chondritic planetesimals,
assembled before the giant impact phase of chaotic growth, potentially yield
important implications for the final composition and evolution of terrestrial
planets. These parameters critically depend on the internal balance of heating
versus cooling, which is mostly determined by the presence of short-lived
radionuclides (SLRs), such as aluminum-26 and iron-60, as well as the heat
conductivity of the material. The heating by SLRs depends on their initial
abundances, the formation time of the planetesimal and its size. It has been
argued that the cooling history is determined by the porosity of the granular
material, which undergoes dramatic changes via compaction processes and tends
to decrease with time. In this study we assess the influence of these
parameters on the thermo-mechanical evolution of young planetesimals with both
2D and 3D simulations. Using the code family I2ELVIS/I3ELVIS we have run
numerous 2D and 3D numerical finite-difference fluid dynamic models with
varying planetesimal radius, formation time and initial porosity. Our results
indicate that powdery materials lowered the threshold for melting and
convection in planetesimals, depending on the amount of SLRs present. A subset
of planetesimals retained a powdery surface layer which lowered the thermal
conductivity and hindered cooling. The effect of initial porosity was small,
however, compared to those of planetesimal size and formation time, which
dominated the thermo-mechanical evolution and were the primary factors for the
onset of melting and differentiation. We comment on the implications of this
work concerning the structure and evolution of these planetesimals, as well as
their behavior as possible building blocks of terrestrial planets.
| arxiv topic:astro-ph.EP physics.geo-ph |
arxiv_dataset-71551603.06079 | Smoothed Temporal Variance Spectrum: weak line profile variations and
NRP diagnostics
astro-ph.SR
We describe the version of the Temporal Variance Spectrum (TVS, Fullerton,
Gies & Bolton 1996) method with pre-smoothed line profile (smoothed Temporal
Variance Spectrum, smTVS). This method introduced by Kholtygin et al. (2003)
can be used to detect the ultra weak variations of the line profile even for
very noisy stellar spectra. We also describe how to estimate the mode of the
non-radial pulsations (NRP) using the TVS and smTVS with different time spans.
The influence of the rotational modulation of the line profile on the TVS is
considered. The analysis of the contribution of NRP and rotational modulation
in the global TVS is studied.
| arxiv topic:astro-ph.SR |
arxiv_dataset-71561603.06179 | On the inhomogeneous spectrum of period two quadratics
math.NT
We give a complete description of the inhomogeneous spectrum of period two
quadratics down to the first limit point.
| arxiv topic:math.NT |
arxiv_dataset-71571603.06279 | Pressure and compressibility of conformal field theories from the
AdS/CFT correspondence
hep-th gr-qc
The equation of state associated with ${\cal N}=4$ supersymmetric Yang-Mills
in 4 dimensions, for $SU(N)$ in the large $N$ limit, is investigated using the
AdS/CFT correspondence. An asymptotically AdS black-hole on the gravity side
provides a thermal background for the Yang-Mills theory on the boundary in
which the cosmological constant is equivalent to a volume. The thermodynamic
variable conjugate to the cosmological constant is a pressure and the $P-V$
diagram is studied. It is known that there is a critical point where the heat
capacity diverges and this is reflected in the isothermal compressibility.
Critical exponents are derived and found to be mean field in the large $N$
limit. The same analysis applied to 3 and 6 dimensional conformal field
theories again yields mean field exponents associated with the compressibility
at the critical point.
| arxiv topic:hep-th gr-qc |
arxiv_dataset-71581603.06379 | Analysis of UV and EUV emission from impacts on the Sun after 2011 June
7 eruptive flare
astro-ph.SR
On 2011 June 7 debris from a large filament eruption fell back to the Sun
causing bright ultraviolet (UV) and extreme ultraviolet (EUV) splashes across
the surface. These impacts may give clues on the process of stellar accretion.
The aim is to investigate how the impact emission is influenced by structures
in the falling ejecta and at the solar surface. We determine the UV and EUV
light curves of a sample of impacts. The ballistic impact velocity is estimated
from the ejection and landing times and, where possible, compared with the
velocity derived by tracking the downflows in SDO/AIA and STEREO/EUVI images.
Estimates of the column density before impact are made from the darkness of the
falling plasma in the 193 A channel. The impact velocities were between 230 and
450 km/s. All impacts produced bright EUV emission at the impact site but
bright UV was only observed when the impacting fragments reached the
chromosphere. There was no clear relation between EUV intensity and kinetic
energy. Low UV to EUV intensity ratios (I{UV}/I{EUV}) were seen (i) from
impacts of low column-density fragments, (ii) when splashes, produced by some
impacts, prevented subsequent fragments from reaching the chromosphere, and
(iii) from an impact in an active region. The earliest impacts with the lowest
velocity (~250 km/s) had the highest I{UV}/I{EUV}. The I{UV}/I{EUV} decreases
with impact velocity, magnetic field at the impact site, and EUV ionising flux.
Many of the infalling fragments dissipate above the chromosphere either due to
ionisation and trapping in magnetic structures, or to them encountering a
splash from an earlier impact. If the same happens in accreting stars then the
reduced X-ray compared to optical emission that has been observed is more
likely due to absorption by the trailing stream than locally at the impact
site.
| arxiv topic:astro-ph.SR |
arxiv_dataset-71591603.06479 | Positive clusters for smooth perturbations of a critical elliptic
equation in dimensions four and five
math.AP
We construct clustering positive solutions for a perturbed critical elliptic
equation on a closed manifold of dimension $n=4,5$. Such a construction is
already available in the literature in dimensions $n\ge 6$ (see for instance
[8,12,27,29,33]) and not possible in dimension $3$ by [25]. This also provides
new patterns for the Lin--Ni [21] problem on closed manifolds and completes
results by Br\'ezis and Li [6] about this problem.
| arxiv topic:math.AP |
arxiv_dataset-71601603.06579 | Exact results for ABJ Wilson loops and open-closed duality
hep-th
We find new exact relations between the partition function and vacuum
expectation values (VEVs) of 1/2 BPS Wilson loops in ABJ theory, which allow us
to predict the large N expansions of the 1/2 BPS Wilson loops from known
results of the partition function. These relations are interpreted as an
open-closed duality where the closed string background is shifted by the
insertion of Wilson loops due to a back-reaction. Using the connection between
ABJ theory and the topological string on local P1 x P1, we explicitly write
down non-trivial relations between open and closed string amplitudes.
| arxiv topic:hep-th |
arxiv_dataset-71611603.06679 | Recursive Neural Conditional Random Fields for Aspect-based Sentiment
Analysis
cs.CL cs.IR cs.LG
In aspect-based sentiment analysis, extracting aspect terms along with the
opinions being expressed from user-generated content is one of the most
important subtasks. Previous studies have shown that exploiting connections
between aspect and opinion terms is promising for this task. In this paper, we
propose a novel joint model that integrates recursive neural networks and
conditional random fields into a unified framework for explicit aspect and
opinion terms co-extraction. The proposed model learns high-level
discriminative features and double propagate information between aspect and
opinion terms, simultaneously. Moreover, it is flexible to incorporate
hand-crafted features into the proposed model to further boost its information
extraction performance. Experimental results on the SemEval Challenge 2014
dataset show the superiority of our proposed model over several baseline
methods as well as the winning systems of the challenge.
| arxiv topic:cs.CL cs.IR cs.LG |
arxiv_dataset-71621603.06779 | Direct Detection of Lyman Continuum Escape from Local Starburst Galaxies
with the Cosmic Origins Spectrograph
astro-ph.GA
We report on the detection of Lyman continuum radiation in two nearby
starburst galaxies. Tol 0440-381, Tol 1247-232 and Mrk 54 were observed with
the Cosmic Origins Spectrograph onboard the Hubble Space Telescopes. The three
galaxies have radial velocities of ~13,000 km/s, permitting a ~35 A window on
the restframe Lyman continuum shortward of the Milky Way Lyman edge at 912 A.
The chosen instrument configuration using the G140L grating covers the spectral
range from 912 to 2,000 {\AA}. We developed a dedicated background subtraction
method to account for temporal and spatial background variations of the
detector, which is crucial at the low flux levels around 912 A. This modified
pipeline allowed us to significantly improve the statistical and systematic
detector noise and will be made available to the community. We detect Lyman
continuum in all three galaxies. However, we conservatively interpret the
emission in Tol 0440-381 as an upper limit due to possible contamination by
geocoronal Lyman series lines. We determined the current star-formation
properties from the far-ultraviolet continuum and spectral lines and used
synthesis models to predict the Lyman continuum radiation emitted by the
current population of hot stars. We discuss the various model uncertainties
such as, among others, atmospheres and evolution models. Lyman continuum escape
fractions were derived from a comparison between the observed and predicted
Lyman continuum fluxes. Tol 1247-232, Mrk 54 and Tol 0440-381 have absolute
escape fractions of (4.5 +/- 1.2)%, (2.5 +/- 0.72)% and <(7.1 +/- 1.1)%,
respectively.
| arxiv topic:astro-ph.GA |
arxiv_dataset-71631603.06879 | A Unifying Framework for the Identification of Motor Primitives
q-bio.NC
A long-standing hypothesis in neuroscience is that the central nervous system
accomplishes complex motor behaviors through the combination of a small number
of motor primitives. Many studies in the last couples of decades have
identified motor primitives at the kinematic, kinetic, and electromyographic
level, thus supporting modularity at different levels of organization in the
motor system. However, these studies relied on heterogeneous definitions of
motor primitives and on different algorithms for their identification. Standard
unsupervised learning algorithms such as principal component analysis,
independent component analysis, and non-negative matrix factorization, or more
advanced techniques involving the estimation of temporal delays of the relevant
mixture components have been applied. This plurality of algorithms has made
difficult to compare and interpret results obtained across different studies.
Moreover, how the different definitions of motor primitives relate to each
other has never been examined systematically. Here we propose a comprehensive
framework for the definition of different types of motor primitives and a
single algorithm for their identification. By embedding smoothness priors and
specific constraints in the underlying generative model, the algorithm can
identify many different types of motor primitives. We assessed the
identification performance of the algorithm both on simulated data sets, for
which the properties of the primitives and of the corresponding combination
parameters were known, and on experimental electromyographic and kinematic data
sets, collected from human subjects accomplishing goal-oriented and rhythmic
motor tasks. The identification accuracy of the new algorithm was typically
equal or better than the accuracy of other unsupervised learning algorithms
used previously for the identification of the same types of primitives.
| arxiv topic:q-bio.NC |
arxiv_dataset-71641603.06979 | Wavelets and spectral triples for fractal representations of Cuntz
algebras
math.OA
In this article we provide an identification between the wavelet
decompositions of certain fractal representations of $C^*-$algebras of directed
graphs of M. Marcolli and A. Paolucci, and the eigenspaces of Laplacians
associated to spectral triples constructed from Cantor fractal sets that are
the infinite path spaces of Bratteli diagrams associated to the
representations, with a particular emphasis on wavelets for representations of
$\mathcal{O}_D$. In particular, in this setting we use results of J. Pearson
and J. Bellissard, and A. Julien and J. Savinien, to construct first the
spectral triple and then the Laplace Beltrami operator on the associated Cantor
set. We then prove that in certain cases, the orthogonal wavelet decomposition
and the decomposition via orthogonal eigenspaces match up precisely. We give
several explicit examples, including an example related to a Sierpinski
fractal, and compute in detail all the eigenvalues and corresponding
eigenspaces of the Laplace Beltrami operators for the equal weight case for
representations of Cuntz algebras, and in the uneven weight case for certain
representations of $\mathcal{O}_2$, and show how the eigenspaces and wavelet
subspaces at different levels are related.
| arxiv topic:math.OA |
arxiv_dataset-71651603.07079 | Ramanujan and coefficients of meromorphic modular forms
math.NT
The study of Fourier coefficients of meromorphic modular forms dates back to
Ramanujan, who, together with Hardy, studied the reciprocal of the weight 6
Eisenstein series. Ramanujan conjectured a number of further identities for
other meromorphic modular forms and quasi-modular forms which were subsequently
established by Berndt, Bialek, and Yee. In this paper, we place these
identities into the context of a larger family by making use of Poincar\'e
series introduced by Petersson and a new family of Poincar\'e series which we
construct here and which are of independent interest. In addition we establish
a number of new explicit identities. In particular, we give the first examples
of Fourier expansions for meromorphic modular form with third-order poles and
quasi-meromorphic modular forms with second-order poles.
| arxiv topic:math.NT |
arxiv_dataset-71661603.07179 | Minuscule weights and Chevalley groups
math.RT
The traditional construction of Chevalley groups relies on the choice of
certain signs for a Chevalley basis of the underlying Lie
algebra~$\mathfrak{g}$. Recently, Lusztig simplified this construction for
groups of adjoint type by using the "canonical basis" of the adjoint
representation of~$\mathfrak{g}$, in particular, no choices of signs are
required. The purpose of this note is to extend this to Chevalley groups which
are not necessarily of adjoint type, using Jantzen's explicit models of the
minuscule highest weight representations of~$\mathfrak{g}$.
| arxiv topic:math.RT |
arxiv_dataset-71671603.07279 | Spatial Global Sensitivity Analysis of High Resolution classified
topographic data use in 2D urban flood modelling
stat.AP math.NA
This paper presents a spatial Global Sensitivity Analysis (GSA) approach in a
2D shallow water equations based High Resolution (HR) flood model. The aim of a
spatial GSA is to produce sensitivity maps which are based on Sobol index
estimations. Such an approach allows to rank the effects of uncertain HR
topographic data input parameters on flood model output. The influence of the
three following parameters has been studied: the measurement error, the level
of details of above-ground elements representation and the spatial
discretization resolution. To introduce uncertainty, a Probability Density
Function and discrete spatial approach have been applied to generate 2, 000
DEMs. Based on a 2D urban flood river event modelling, the produced sensitivity
maps highlight the major influence of modeller choices compared to HR
measurement errors when HR topographic data are used, and the spatial
variability of the ranking. Highlights $\bullet$ Spatial GSA allowed the
production of Sobol index maps, enhancing the relative weight of each uncertain
parameter on the variability of calculated output parameter of interest. 1
$\bullet$ The Sobol index maps illustrate the major influence of the modeller
choices, when using the HR topographic data in 2D hydraulic models with respect
to the influence of HR dataset accuracy. $\bullet$ Added value is for modeller
to better understand limits of his model. $\bullet$ Requirements and limits for
this approach are related to subjectivity of choices and to computational cost.
| arxiv topic:stat.AP math.NA |
arxiv_dataset-71681603.07379 | Diffusive Wave in the Low Mach Limit for Compressible Navier-Stokes
Equations
math.AP
The low Mach limit for 1D non-isentropic compressible Navier-Stokes flow,
whose density and temperature have different asymptotic states at infinity, is
rigorously justified. The problems are considered on both well-prepared and
ill-prepared data. For the well-prepared data, the solutions of compressible
Navier-Stokes equations are shown to converge to a nonlinear diffusion wave
solution globally in time as Mach number goes to zero when the difference
between the states at $\pm\infty$ is suitably small. In particular, the
velocity of diffusion wave is only driven by the variation of temperature. It
is further shown that the solution of compressible Navier-Stokes system also
has the same property when Mach number is small, which has never been observed
before. The convergence rates on both Mach number and time are also obtained
for the well-prepared data. For the ill-prepared data, the limit relies on the
uniform estimates including weighted time derivatives and an extended
convergence lemma. And the difference between the states at $\pm\infty$ can be
arbitrary large in this case.
| arxiv topic:math.AP |
arxiv_dataset-71691603.07479 | Global persistence of geometrical structures for the boussinesq equation
with no diffusion
math.AP
Here we investigate the so-called temperature patch problem for the
incompressible Boussinesq system with partial viscosity, in the whole space
$\mathbb{R}^N$ $(N \geq 2)$, where the initial temperature is the
characteristic function of some simply connected domain with $C^{1,
\varepsilon}$ H{\"o}lder regularity. Although recent results in [1, 15] ensure
that an initially $C^1$ patch persists through the evolution, whether higher
regularity is preserved has remained an open question. In the present paper, we
give a positive answer to that issue globally in time, in the 2-D case for
large initial data and in the higher dimension case for small initial data.
| arxiv topic:math.AP |
arxiv_dataset-71701603.07579 | Target selection of classical pulsating variables for space-based
photometry
astro-ph.SR
In a few years the Kepler and TESS missions will provide ultra-precise
photometry for thousands of RR Lyrae and hundreds of Cepheid stars. In the
extended Kepler mission all targets are proposed in the Guest Observer (GO)
Program, while the TESS space telescope will work with full frame images and a
~15-16th mag brightness limit with the possibility of short cadence
measurements for a limited number of pre-selected objects. This paper
highlights some details of the enormous and important work of the target
selection process made by the members of Working Group 7 (WG#7) of the Kepler
and TESS Asteroseismic Science Consortium.
| arxiv topic:astro-ph.SR |
arxiv_dataset-71711603.07679 | Tunneling from a Minkowski vacuum to an AdS vacuum: A new thin-wall
regime
hep-th
Using numerical and analytic methods, we study quantum tunneling from a
Minkowski false vacuum to an anti-de Sitter true vacuum. Scanning the parameter
space of theories with quartic and non-polynomial potentials, we find that for
any given potential tunneling is completely quenched if gravitational effects
are made sufficiently strong. For potentials where $\epsilon$, the energy
density difference between the vacua, is small compared to the barrier height,
this occurs in the thin-wall regime studied by Coleman and De Luccia. However,
we find that other potentials, possibly with $\epsilon$ much greater than the
barrier height, produce a new type of thin-wall bounce when gravitational
effects become strong. We show that the critical curve that bounds the region
in parameter space where the false vacuum is stable can be found by a
computationally simple overshoot/undershoot argument. We discuss the treatment
of boundary terms in the bounce calculation and show that, with proper
regularization, one obtains an identical finite result for the tunneling
exponent regardless of whether or not these are included. Finally, we briefly
discuss the extension of our results to transitions between anti-de Sitter
vacua.
| arxiv topic:hep-th |
arxiv_dataset-71721603.07779 | Nonnegative Rank vs. Binary Rank
cs.CC cs.DM
Motivated by (and using tools from) communication complexity, we investigate
the relationship between the following two ranks of a $0$-$1$ matrix: its
nonnegative rank and its binary rank (the $\log$ of the latter being the
unambiguous nondeterministic communication complexity). We prove that for
partial $0$-$1$ matrices, there can be an exponential separation. For total
$0$-$1$ matrices, we show that if the nonnegative rank is at most $3$ then the
two ranks are equal, and we show a separation by exhibiting a matrix with
nonnegative rank $4$ and binary rank $5$, as well as a family of matrices for
which the binary rank is $4/3$ times the nonnegative rank.
| arxiv topic:cs.CC cs.DM |
arxiv_dataset-71731603.07879 | Hybridization of Expectation-Maximization and K-Means Algorithms for
Better Clustering Performance
cs.LG stat.ML
The present work proposes hybridization of Expectation-Maximization (EM) and
K-Means techniques as an attempt to speed-up the clustering process. Though
both K-Means and EM techniques look into different areas, K-means can be viewed
as an approximate way to obtain maximum likelihood estimates for the means.
Along with the proposed algorithm for hybridization, the present work also
experiments with the Standard EM algorithm. Six different datasets are used for
the experiments of which three are synthetic datasets. Clustering fitness and
Sum of Squared Errors (SSE) are computed for measuring the clustering
performance. In all the experiments it is observed that the proposed algorithm
for hybridization of EM and K-Means techniques is consistently taking less
execution time with acceptable Clustering Fitness value and less SSE than the
standard EM algorithm. It is also observed that the proposed algorithm is
producing better clustering results than the Cluster package of Purdue
University.
| arxiv topic:cs.LG stat.ML |
arxiv_dataset-71741603.07979 | Flat Directions and Leptogenesis in a "New" $\mu \nu$SSM
hep-ph
In this paper, we give a brief review of the Minimal Supersymmetric Standard
Model (MSSM) and "$\mu$ from $\nu$" Supersymmetric Standard Model ($\mu
\nu$SSM). Then we propose a generalization of $\mu \nu$SSM in order to explain
the recent ATLAS, CMS and LHCb results. This "new" $\mu \nu$SSM generalizes the
superpotential $W_{suppot}$ of $\mu \nu$SSM by including two terms that
generate a mixing among leptons, gauginos and higgsinos while keeping the
charginos and neutralinos masses unchanged. Also, it is potentially interesting
for cosmological applications as it displays flat directions of the
superpotential and a viable leptogenesis mechanism.
| arxiv topic:hep-ph |
arxiv_dataset-71751603.08079 | Do You See What I Mean? Visual Resolution of Linguistic Ambiguities
cs.CV cs.AI cs.CL
Understanding language goes hand in hand with the ability to integrate
complex contextual information obtained via perception. In this work, we
present a novel task for grounded language understanding: disambiguating a
sentence given a visual scene which depicts one of the possible interpretations
of that sentence. To this end, we introduce a new multimodal corpus containing
ambiguous sentences, representing a wide range of syntactic, semantic and
discourse ambiguities, coupled with videos that visualize the different
interpretations for each sentence. We address this task by extending a vision
model which determines if a sentence is depicted by a video. We demonstrate how
such a model can be adjusted to recognize different interpretations of the same
underlying sentence, allowing to disambiguate sentences in a unified fashion
across the different ambiguity types.
| arxiv topic:cs.CV cs.AI cs.CL |
arxiv_dataset-71761603.08179 | Channel Hopping Sequences for Maximizing Rendezvous Diversity in
Cognitive Radio Networks
cs.IT math.IT
In cognitive radio networks (CRNs), establishing a communication link between
a pair of secondary users (SUs) requires them to rendezvous on a common channel
which is not occupied by primary users (PUs). Under time-varying PU traffic,
asynchronous sequence-based channel hopping (CH) with the maximal rendezvous
diversity is a representative technique to guarantee an upper bounded
time-torendezvous (TTR) for delay-sensitive services in CRNs, without requiring
global clock synchronization. Maximum TTR (MTTR) and maximum conditional TTR
(MCTTR) are two commonly considered metrics for evaluating such CH sequences,
and minimizing these two metrics is the primary goal in the sequence design of
various paper reported in the literature. In this paper, to investigate the
fundamental limits of these two metrics, we first derive lower bounds on the
MCTTR and MTTR, and then propose an asymmetric design which has the minimum
MCTTR and an improvement on MTTR than other previously known algorithms.
Moreover, when the number of licensed channels is odd, our proposed design
achieves the minimum MTTR. We also present the TTR performance of the proposed
design via simulation.
| arxiv topic:cs.IT math.IT |
arxiv_dataset-71771603.08279 | Small Ball Probabilities for the Infinite-Dimensional Ornstein-Uhlenbeck
Process in Sobolev Spaces
math.PR
While small ball, or lower tail, asymptotic for Gaussian measures generated
by solutions of stochastic ordinary differential equations is relatively well
understood, a lot less is known in the case of stochastic partial differential
equations. The paper presents exact logarithmic asymptotics of the small ball
probabilities in a scale of Sobolev spaces when the Gaussian measure is
generated by the solution of a diagonalizable stochastic parabolic equation.
Compared to the finite-dimensional case, new effects appear in a certain
range of the Sobolev exponents.
| arxiv topic:math.PR |
arxiv_dataset-71781603.08379 | Probabilistic Programming for Malware Analysis
cs.CR
Constructing lineages of malware is an important cyber-defense task.
Performing this task is difficult, however, due to the amount of malware data
and obfuscation techniques by the authors. In this work, we formulate the
lineage task as a probabilistic model, and use a novel probabilistic
programming solution to jointly infer the lineage and creation times of
families of malware.
| arxiv topic:cs.CR |
arxiv_dataset-71791603.08479 | The congruent numbers have positive natural density
math.NT
We prove that the rational elliptic curve y^2 = x^3 - n^2x satisfies the full
Birch and Swinnerton-Dyer conjecture for at least 41.9% of positive squarefree
integers n equal to 1, 2, or 3 mod 8, and that it satisfies the regular BSD
conjecture for at least 55.9% of positive squarefree integers n equal to 5, 6,
or 7 mod 8. In particular, at least 55.9% of positive squarefree integers equal
to 5, 6, or 7 mod 8 are congruent numbers. These proofs complete an argument
started by Tian, Yuan, and Zhang.
| arxiv topic:math.NT |
arxiv_dataset-71801603.08579 | Negation and partial axiomatizations of dependence and independence
logic revisited
math.LO
In this paper, we axiomatize the negatable consequences in dependence and
independence logic by extending the systems of natural deduction of the logics
given in (Kontinen and Vaananen 2013) and (Hannula 2015). We prove a
characterization theorem for negatable formulas in independence logic and
negatable sentences in dependence logic, and identify an interesting class of
formulas that are negatable in independence logic. Dependence and independence
atoms, first-order formulas belong to this class. We also demonstrate our
extended system of independence logic by giving explicit derivations for
Armstrong's Axioms and the Geiger-Paz-Pearl axioms of dependence and
independence atoms.
| arxiv topic:math.LO |
arxiv_dataset-71811603.08679 | Probing Models of Dirac Neutrino Masses via the Flavor Structure of the
Mass Matrix
hep-ph
We classify models of the Dirac neutrino mass by concentrating on flavor
structures of the mass matrix. The advantage of our classification is that we
do not need to specify detail of models except for Yukawa interactions because
flavor structures can be given only by products of Yukawa matrices. All
possible Yukawa interactions between leptons (including the right-handed
neutrino) are taken into account by introducing appropriate scalar fields. We
also take into account the case with Yukawa interactions of leptons with the
dark matter candidate. Then, we see that flavor structures can be classified
into seven groups. The result is useful for the efficient test of models of the
neutrino mass. One of seven groups can be tested by measuring the absolute
neutrino mass. Other two can be tested by probing the violation of the lepton
universality in $\ell \to \ell^\prime \nu \overline{\nu}$. In order to test the
other four groups, we can rely on searches for new scalar particles at collider
experiments.
| arxiv topic:hep-ph |
arxiv_dataset-71821603.08779 | Coronas and domination subdivision number of a graph
math.CO
In this paper, for a graph G and a family of partitions P of vertex
neighborhoods of G, we define the general corona G \circ P of G. Among several
properties of this new operation, we focus on application general coronas to a
new kind of characterization of trees with the domination subdivision number
equal to 3.
| arxiv topic:math.CO |
arxiv_dataset-71831603.08879 | Energy-momentum mapping of d-derived Au(111) states in a thin film
cond-mat.mtrl-sci
The quantum well states of a film can be used to sample the electronic
structure of the parent bulk material and determine its band parameters. We
highlight the benefits of two-dimensional film band mapping, with respect to
complex bulk analysis, in an angle-resolved photoemission spectroscopy study of
the 5d states of Au(111). Discrete 5d-derived quantum well states of various
orbital characters form in Au(111) films and span the width of the
corresponding bulk bands. For sufficiently thick films, the dispersion of these
states samples the bulk band edges, as confirmed by first-principles
calculations, thus providing the positions of the critical points of bulk Au in
agreement with previously determined values. In turn, this analysis identifies
several d-like surface states and resonances with large spin-splittings that
originate from the strong spin-orbit coupling of the Au 5d atomic levels.
| arxiv topic:cond-mat.mtrl-sci |
arxiv_dataset-71841603.08979 | Isomorphismes entre des espaces de mesures \`a valeurs vectorielles
math.FA
Let $(\Omega_1, \mathcal{F}_1, \mu_1)$, $(\Omega_2, \mathcal{F}_2, \mu_2)$ be
two probabilty spaces, $1\leq p\leq +\infty$ and $X$ a Banach space. In this
work we show that $L^p(\mu_1, X)$, $VB^p (\mu_1,X),$ $cabv(\mu_{1},X)$ are
isomorphic to $L^p(\mu_2, X),$ $VB^p(\mu_2, X)$, $cabc(\mu_2, X)$ respectively,
if $L^1(\mu_1)$ is strongly isomorphic to $L^1(\mu_2)$.
| arxiv topic:math.FA |
arxiv_dataset-71851603.09079 | Some new dynamic Inequality on time scales in three variables
math.DS
In this paper we obtain the estimates on some dynamic integral inequalities
in three variables which can be used to study certain dynamic equations. We
give some applications to convey the importance of our result.
| arxiv topic:math.DS |
arxiv_dataset-71861603.09179 | Rotation periods for cool stars in the 4 Gyr-old open cluster M67, the
solar-stellar connection, and the applicability of gyrochronology to at least
solar age
astro-ph.SR
We report rotation periods for 20 cool (FGK) main sequence member stars of
the 4 Gyr-old open cluster M 67 (= NGC 2682), obtained by analysing data from
Campaign 5 of the K2 mission with the Kepler Space Telescope. The rotation
periods delineate a sequence in the color-period diagram (CPD) of increasing
period with redder color. This sequence represents a cross-section at the
cluster age of the surface P = P (t, M), suggested in prior work to extend to
at least solar age. The current Sun is located marginally (approx. one sigma)
above M 67 in the CPD, as its relative age leads us to expect, and lies on the
P = P (t, M) surface to within measurement precision. We therefore conclude
that the solar rotation rate is normal, as compared with cluster stars, a fact
which strengthens the solar-stellar connection. The agreement between the M\,67
rotation period measurements and prior predictions further implies that
rotation periods, especially when coupled with appropriate supporting work such
as spectroscopy, can provide reliable ages via gyrochronology for other similar
FGK dwarfs from the early main sequence to solar age and likely till the main
sequence turnoff. The M 67 rotators have a rotational age of 4.2 Gyr, with a
standard deviation of 0.7 Gyr, implying that similar field stars can be
age-dated to precisions of ~17%. The rotational age of the M 67 cluster as a
whole is therefore 4.2 Gyr, but with a lower (averaged) uncertainty of 0.2 Gyr.
| arxiv topic:astro-ph.SR |
arxiv_dataset-71871603.09279 | On the Geometry of Message Passing Algorithms for Gaussian Reciprocal
Processes
stat.ML math.OC
Reciprocal processes are acausal generalizations of Markov processes
introduced by Bernstein in 1932. In the literature, a significant amount of
attention has been focused on developing dynamical models for reciprocal
processes. Recently, probabilistic graphical models for reciprocal processes
have been provided. This opens the way to the application of efficient
inference algorithms in the machine learning literature to solve the smoothing
problem for reciprocal processes. Such algorithms are known to converge if the
underlying graph is a tree. This is not the case for a reciprocal process,
whose associated graphical model is a single loop network. The contribution of
this paper is twofold. First, we introduce belief propagation for Gaussian
reciprocal processes. Second, we establish a link between convergence analysis
of belief propagation for Gaussian reciprocal processes and stability theory
for differentially positive systems.
| arxiv topic:stat.ML math.OC |
arxiv_dataset-71881603.09379 | Co-t-structures: The First Decade
math.RT math.RA
Co-t-structures were introduced about ten years ago as a type of mirror image
of t-structures. Like t-structures, they permit to divide an object in a
triangulated category T into a "left part" and a "right part", but there are
crucial differences. For instance, a bounded t-structure gives rise to an
abelian subcategory of T, while a bounded co-t-structure gives rise to a
so-called silting subcategory.
This brief survey will emphasise three philosophical points. First, bounded
t-structures are akin to the canonical example of "soft" truncation of
complexes in the derived category. Secondly, bounded co-t-structures are akin
to the canonical example of "hard" truncation of complexes in the homotopy
category.
Thirdly, a triangulated category T may be skewed towards t-structures or
co-t-structures, in the sense that one type of structure is more useful than
the other for studying T. In particular, we think of derived categories as
skewed towards t-structures, and of homotopy categories as skewed towards
co-t-structures.
| arxiv topic:math.RT math.RA |
arxiv_dataset-71891603.09479 | Application of Geometric Calculus in Numerical Analysis and Difference
Sequence Spaces
math.FA
The main purpose of this paper is to introduce the geometric difference
sequence space
$l_\infty^{G} (\Delta_G)$ and prove that $l_\infty^{G} ({\Delta}_{G})$ is a
Banach space with respect to the norm $\left\|.\right\|^G_{{\Delta}_G}.$ Also
we compute the $\alpha$-dual, $\beta$-dual and $\gamma$-dual spaces. Finally we
obtain the Geometric Newton-Gregory interpolation formulae.
| arxiv topic:math.FA |
arxiv_dataset-71901603.09579 | An inequality concerning the growth bound of a discrete evolution family
on a complex Banach space
math.FA
We prove that the uniform growth bound $\omega_0(\mathcal{U})$ of a discrete
evolution family $\mathcal{U}$ of bounded linear operators acting on a complex
Banach space $X$ satisfies the inequality
$$\omega_0(\mathcal{U})c_{\mathcal{U}}(\mathcal{X})\le -1;$$ here
$c_{\mathcal{U}}(\mathcal{X})$ is the operator norm of a convolution operator
which acts on a certain Banach space $\mathcal{X}$ of $X$-valued sequences.
| arxiv topic:math.FA |
arxiv_dataset-71911603.09679 | Towards co-designed optimizations in parallel frameworks: A MapReduce
case study
cs.DC
The explosion of Big Data was followed by the proliferation of numerous
complex parallel software stacks whose aim is to tackle the challenges of data
deluge. A drawback of a such multi-layered hierarchical deployment is the
inability to maintain and delegate vital semantic information between layers in
the stack. Software abstractions increase the semantic distance between an
application and its generated code. However, parallel software frameworks
contain inherent semantic information that general purpose compilers are not
designed to exploit.
This paper presents a case study demonstrating how the specific semantic
information of the MapReduce paradigm can be exploited on multicore
architectures. MR4J has been implemented in Java and evaluated against
hand-optimized C and C++ equivalents. The initial observed results led to the
design of a semantically aware optimizer that runs automatically without
requiring modification to application code.
The optimizer is able to speedup the execution time of MR4J by up to 2.0x.
The introduced optimization not only improves the performance of the generated
code, during the map phase, but also reduces the pressure on the garbage
collector. This demonstrates how semantic information can be harnessed without
sacrificing sound software engineering practices when using parallel software
frameworks.
| arxiv topic:cs.DC |
arxiv_dataset-71921604.00033 | EMBERS at 4 years: Experiences operating an Open Source Indicators
Forecasting System
cs.CY cs.SI
EMBERS is an anticipatory intelligence system forecasting population-level
events in multiple countries of Latin America. A deployed system from 2012,
EMBERS has been generating alerts 24x7 by ingesting a broad range of data
sources including news, blogs, tweets, machine coded events, currency rates,
and food prices. In this paper, we describe our experiences operating EMBERS
continuously for nearly 4 years, with specific attention to the discoveries it
has enabled, correct as well as missed forecasts, and lessons learnt from
participating in a forecasting tournament including our perspectives on the
limits of forecasting and ethical considerations.
| arxiv topic:cs.CY cs.SI |
arxiv_dataset-71931604.00133 | Good Practice in CNN Feature Transfer
cs.CV
The objective of this paper is the effective transfer of the Convolutional
Neural Network (CNN) feature in image search and classification.
Systematically, we study three facts in CNN transfer. 1) We demonstrate the
advantage of using images with a properly large size as input to CNN instead of
the conventionally resized one. 2) We benchmark the performance of different
CNN layers improved by average/max pooling on the feature maps. Our observation
suggests that the Conv5 feature yields very competitive accuracy under such
pooling step. 3) We find that the simple combination of pooled features
extracted across various CNN layers is effective in collecting evidences from
both low and high level descriptors. Following these good practices, we are
capable of improving the state of the art on a number of benchmarks to a large
margin.
| arxiv topic:cs.CV |
arxiv_dataset-71941604.00233 | Building an Internet Radio System with Interdisciplinary factored system
for automatic content recommendation
cs.CY cs.IR cs.MM
Automatic systems for music content recommendation have assumed a new role in
recent years. These systems have transformed from being just a convenient,
standalone tool into an inseparable element of modern living. In addition, not
only do these systems strongly influence human moods and feelings with the
selection of proper music content, but they also provide significant commercial
and advertising opportunities. This research aims to examine and implement two
such systems available for the automatic recognition and recommendation of
music and advertisement content for Internet radio. Through analysis of the
practical issues of application fields and spheres of influence, conclusions
will be drawn about the possible perspectives on and future role of such
systems. Other content adaptation that is based on music genres will be
discussed, as wellAnother aim of this study is to provide an innovative
Internet radio implementation as compared to traditional radio and other
Internet broadcast solutions. This will include automatic content
recommendation systems for listeners and marketing companies, as well as the
usage of a voice synthesizer in in automatic program scheduling.
| arxiv topic:cs.CY cs.IR cs.MM |
arxiv_dataset-71951604.00333 | Prospects for Future Collider Physics
hep-ph
One item on the agenda of future colliders is certain to be the Higgs boson.
What is it trying to tell us? The primary objective of any future collider must
surely be to identify physics beyond the Standard Model, and supersymmetry is
one of the most studied options. it Is supersymmetry waiting for us and, if so,
can LHC Run 2 find it? The big surprise from the initial 13-TeV LHC data has
been the appearance of a possible signal for a new boson X with a mass ~750
GeV. What are the prospects for future colliders if the X(750) exists? One of
the most intriguing possibilities in electroweak physics would be the discovery
of non-perturbative phenomena. What are the prospects for observing sphalerons
at the LHC or a future collider?
| arxiv topic:hep-ph |
arxiv_dataset-71961604.00433 | Adapting Models to Signal Degradation using Distillation
cs.CV
Model compression and knowledge distillation have been successfully applied
for cross-architecture and cross-domain transfer learning. However, a key
requirement is that training examples are in correspondence across the domains.
We show that in many scenarios of practical importance such aligned data can be
synthetically generated using computer graphics pipelines allowing domain
adaptation through distillation. We apply this technique to learn models for
recognizing low-resolution images using labeled high-resolution images,
non-localized objects using labeled localized objects, line-drawings using
labeled color images, etc. Experiments on various fine-grained recognition
datasets demonstrate that the technique improves recognition performance on the
low-quality data and beats strong baselines for domain adaptation. Finally, we
present insights into workings of the technique through visualizations and
relating it to existing literature.
| arxiv topic:cs.CV |
arxiv_dataset-71971604.00533 | Voronoi Region-Based Adaptive Unsupervised Color Image Segmentation
cs.CV
Color image segmentation is a crucial step in many computer vision and
pattern recognition applications. This article introduces an adaptive and
unsupervised clustering approach based on Voronoi regions, which can be applied
to solve the color image segmentation problem. The proposed method performs
region splitting and merging within Voronoi regions of the Dirichlet
Tessellated image (also called a Voronoi diagram) , which improves the
efficiency and the accuracy of the number of clusters and cluster centroids
estimation process. Furthermore, the proposed method uses cluster centroid
proximity to merge proximal clusters in order to find the final number of
clusters and cluster centroids. In contrast to the existing adaptive
unsupervised cluster-based image segmentation algorithms, the proposed method
uses K-means clustering algorithm in place of the Fuzzy C-means algorithm to
find the final segmented image. The proposed method was evaluated on three
different unsupervised image segmentation evaluation benchmarks and its results
were compared with two other adaptive unsupervised cluster-based image
segmentation algorithms. The experimental results reported in this article
confirm that the proposed method outperforms the existing algorithms in terms
of the quality of image segmentation results. Also, the proposed method results
in the lowest average execution time per image compared to the existing methods
reported in this article.
| arxiv topic:cs.CV |
arxiv_dataset-71981604.00633 | Positive solutions to sublinear elliptic problem
math.AP
Let $L$ be a second order elliptic operator $L$ with smooth coefficients
defined on a domain $\Omega $ in $\mathbb{R}^d $, $d\geq3$, such that $L1\leq
0$. We study existence and properties of continuous solutions to the following
problem
\begin{equation}\label{00} Lu=\varphi(\cdot,u),% & \hbox{in $\Omega $; in the
sens of distribution;} \\ \end{equation} in $\Omega,$ where $\Omega$ is a
Greenian domain for $L$ {(possibly unbounded)} in $\mathbb{R}^d$ and $\varphi $
is a nonnegative function on $\Omega\times [0,+\infty [$ increasing with
respect to the second variable. By means of thinness, we obtain a
characterization of $\varphi$ for which \eqref{00} has a nonnegative nontrivial
bounded solution.
| arxiv topic:math.AP |
arxiv_dataset-71991604.00733 | On regularity lemmas and their algorithmic applications
math.CO
Szemer\'edi's regularity lemma and its variants are some of the most powerful
tools in combinatorics. In this paper, we establish several results around the
regularity lemma. First, we prove that whether or not we include the condition
that the desired vertex partition in the regularity lemma is equitable has a
minimal effect on the number of parts of the partition. Second, we use an
algorithmic version of the (weak) Frieze--Kannan regularity lemma to give a
substantially faster deterministic approximation algorithm for counting
subgraphs in a graph. Previously, only an exponential dependence for the
running time on the error parameter was known, and we improve it to a
polynomial dependence. Third, we revisit the problem of finding an algorithmic
regularity lemma, giving approximation algorithms for several co-NP-complete
problems. We show how to use the weak Frieze--Kannan regularity lemma to
approximate the regularity of a pair of vertex subsets. We also show how to
quickly find, for each $\epsilon'>\epsilon$, an $\epsilon'$-regular partition
with $k$ parts if there exists an $\epsilon$-regular partition with $k$ parts.
Finally, we give a simple proof of the permutation regularity lemma which
improves the tower-type bound on the number of parts in the previous proofs to
a single exponential bound.
| arxiv topic:math.CO |
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