title:
SED-dependent Galactic Extinction Prescription for Euclid and Future
  Cosmological Surveys

abstract:
  The outcome of upcoming cosmological surveys will depend on the accurate
estimates of photometric redshifts. In the framework of the implementation of
the photo-z algorithm for Euclid, we are exploring new avenues to improve
template-fitting methods. The paper focusses on the prescription of the
extinction of source light by dust in the Milky Way. Since Galactic extinction
strongly correlates with wavelength and photometry is commonly obtained in
broad-band filters, the amount of absorption depends on the source SED, a point
often neglected as the SED is not known a-priori. A consequence of this is that
the observed E(B-V) (=A_B-A_V) will be different from the E(B-V) used to
normalise the absorption law k_lambda (=A_lambda/E(B-V)). Band-pass corrections
are required to renormalise the law for a given SED. We assess the band-pass
corrections of a range of SEDs and find they vary by up to 20%. We investigate
how dust-to-reddening scaling factors depend of the sources used for their
calibration. We derive scaling factors from the color excesses of z<0.4 SDSS
red galaxies and show that band-pass corrections predict the observed
differences. Extinction is then estimated for a range of SEDs and filters
relevant to Euclid and other cosmological ground-based surveys. For high
extinction line-of-sights (E(B-V)>0.1, ~8% of the Euclid survey), the
variations in corrections can be ~0.1mag in the `bluer' optical filters and
~0.04mag in the NIR filters. An inaccurate correction of extinction critically
affects photo-z. In particular, for high extinctions and z<0.5, the bias (mean
D_z=z_phot-z_real) exceeds 0.2%(1+z), the precision required by weak-lensing
analyses. Additional uncertainty on the MW extinction law further reduces the
photo-z precision. We propose a new prescription of Galactic absorption for
template-fitting algorithms that takes into consideration the dependence of
extinction with SED.


title:
BAT AGN Spectroscopic Survey-III. An observed link between AGN Eddington
  ratio and narrow emission line ratios

abstract:
  We investigate the observed relationship between black hole mass ($M_{\rm
BH}$), bolometric luminosity ($L_{\rm bol}$), and Eddington ratio
(${\lambda}_{\rm Edd}$) with optical emission line ratios ([NII]
{\lambda}6583/H{\alpha}, [SII] {\lambda}{\lambda}6716,6731/H{\alpha}, [OI]
{\lambda}6300/H{\alpha}, [OIII] {\lambda}5007/H{\beta}, [NeIII]
{\lambda}3869/H{\beta}, and HeII {\lambda}4686/H{\beta}) of hard X-ray-selected
AGN from the BAT AGN Spectroscopic Survey (BASS). We show that the [NII]
{\lambda}6583/H{\alpha} ratio exhibits a significant correlation with
${\lambda}_{\rm Edd}$ ($R_{\rm Pear}$ = -0.44, $p$-value=$3\times10^{-13}$,
{\sigma} = 0.28 dex), and the correlation is not solely driven by $M_{\rm BH}$
or $L_{\rm bol}$. The observed correlation between [NII]
{\lambda}6583/H{\alpha} ratio and $M_{\rm BH}$ is stronger than the correlation
with $L_{\rm bol}$, but both are weaker than the ${\lambda}_{\rm Edd}$
correlation. This implies that the large-scale narrow lines of AGN host
galaxies carry information about the accretion state of the AGN central engine.
We propose that the [NII] {\lambda}6583/H{\alpha} is a useful indicator of
Eddington ratio with 0.6 dex of rms scatter, and that it can be used to measure
${\lambda}_{\rm Edd}$ and thus $M_{\rm BH}$ from the measured $L_{\rm bol}$,
even for high redshift obscured AGN. We briefly discuss possible physical
mechanisms behind this correlation, such as the mass-metallicity relation,
X-ray heating, and radiatively driven outflows.


title:
A Testable Conspiracy: Simulating Baryonic Effects on Self-Interacting
  Dark Matter Halos

abstract:
  We investigate the response of self-interacting dark matter (SIDM) halos to
the growth of galaxy potentials using idealized simulations, each run in tandem
with standard collisionless Cold Dark Matter (CDM). We find a greater diversity
in the SIDM halo profiles compared to the CDM halo profiles. If the stellar
gravitational potential strongly dominates in the central parts of a galaxy,
then SIDM halos can be as dense as CDM halos on observable scales. For extreme
cases with highly compact disks core collapse can occur, leading to SIDM halos
that are denser and cuspier than their CDM counterparts. If the stellar
potential is not dominant, then SIDM halos retain constant density cores with
densities far below CDM predictions. When a disk potential is present, the
inner SIDM halo becomes \em{more flattened} in the disk plane than the CDM
halo. These results are in excellent quantitative agreement with the
predictions of Kaplinghat et al. (2014). We also simulated a galaxy cluster
halo with a central stellar distribution similar to the brightest central
galaxy of the cluster A2667. A SIDM halo simulated with cross section over mass
$\sigma/m = 0.1\ \mathrm{cm^2 g^{-1}}$ provides a good match to the measured
dark matter density profile of A2667, while an adiabatically-contracted CDM
halo is denser and cuspier. The cored profile of the same halo simulated with
$\sigma/m = 0.5\ \mathrm{cm^2 g^{-1}}$ is not dense enough to match A2667. Our
findings are in agreement with previous results that $\sigma/m \gtrsim 0.1\
\mathrm{cm^2 g^{-1}}$ is disfavored for dark matter collision velocities in
excess of about 1500 km/s. More generally, the predictive cross-talk between
baryonic potentials and SIDM density distributions offers new directions for
constraining SIDM cross sections in massive galaxies where baryons are
dynamically important.


title:
Positivity, Grassmannian Geometry and Simplex-like Structures of
  Scattering Amplitudes

abstract:
  This article revisits and elaborates the significant role of positive
geometry of momentum twistor Grassmannian for planar N=4 SYM scattering
amplitudes. First we establish the fundamentals of positive Grassmannian
geometry for tree amplitudes. Then we formulate this subject around these four
major facets: 1. Deriving the tree and 1-loop BCFW recursion relations solely
from positivity, after introducing the simple building blocks called positive
components. 2. Applying Grassmannian geometry and Pluecker coordinates to
determine the signs in N$^2$MHV homological identities. Most of them in fact
reflect the secret incarnation of the simple 6-term NMHV identity. 3. Deriving
the stacking positivity relation, which is powerful for parameterizing the
matrix representative in terms of positive variables, of a given Grassmannian
geometric configuration. 4. Introducing a highly refined formalism for tree
BCFW recursion relation, which reveals its two-fold simplex-like structures.
First, the BCFW contour in terms of (reduced) Grassmannian geometry
representatives is dissected into a triangle-shape sum, as only a small
fraction of the sum needs to be explicitly identified. Second, this fraction
can be further dissected, according to different growing modes and parameters.
The growing modes possess the shapes of solid simplices of various dimensions,
with which infinite number of BCFW cells can be entirely captured by the
characteristic objects called fully-spanning cells. We find that for a given k,
beyond n=4k+1 there is no more new fully-spanning cell, which signifies the
essential termination of the recursive growth of BCFW cells. As n increases
beyond the termination point, the BCFW contour simply replicates itself
according to the simplex-like patterns, which enables us to master all BCFW
cells once for all without actually identifying most of them.


title:
Coarse-grained hidden entropy production in partially inaccessible
  quantum jump trajectories

abstract:
  We consider an open quantum system for which only a subset of all possible
transitions are accessible, while the remaining ones are hidden from direct
observation. Using a modification of the notion of quantum jump trajectories we
introduce the coarse-grained hidden entropy, which quantifies the entropy
production in the hidden subsystem conditioned on our observations of the
visible part. The entropy production consisting of the sum of visible and
coarse-grained hidden entropy is shown to satisfy an integral fluctuations
theorem. Depending on the nature of the continuously occurring measurement and
feedback processes between the interacting subsystems, the visible entropy can
take negative values in which case the hidden systems acts as a Maxwell's
demon. Our results allow us to study quantum-mechanical effects in autonomous
systems, such as the autonomous quantum Maxwell's demon we introduce as an
illustrative example.


title: The impact of protocluster environments at z = 1.6

abstract:
  We investigate the effects of dense environments on galaxy evolution by
examining how the properties of galaxies in the z = 1.6 protocluster Cl
0218.3-0510 depend on their location. We determine galaxy properties using
spectral energy distribution fitting to 14-band photometry, including data at
three wavelengths that tightly bracket the Balmer and 4000A breaks of the
protocluster galaxies. We find that two-thirds of the protocluster galaxies,
which lie between several compact groups, are indistinguishable from field
galaxies. The other third, which reside within the groups, differ significantly
from the intergroup galaxies in both colour and specific star formation rate.
We find that the fraction of red galaxies within the massive protocluster
groups is twice that of the intergroup region. These excess red galaxies are
due to enhanced fractions of both passive galaxies (1.7 times that of the
intergroup region) and dusty star-forming galaxies (3 times that of the
intergroup region). We infer that some protocluster galaxies are processed in
the groups before the cluster collapses. These processes act to suppress star
formation and change the mode of star formation from unobscured to obscured.


title:
Reconstructing the three-dimensional local dark matter velocity
  distribution

abstract:
  Directionally sensitive dark matter (DM) direct detection experiments present
the only way to observe the full three-dimensional velocity distribution of the
Milky Way halo local to Earth. In this work we compare methods for extracting
information about the local DM velocity distribution from a set of recoil
directions and energies in a range of hypothetical directional and
non-directional experiments. We compare a model independent empirical
parameterisation of the velocity distribution based on an angular
discretisation with a model dependent approach which assumes knowledge of the
functional form of the distribution. The methods are tested under three
distinct halo models which cover a range of possible phase space structures for
the local velocity distribution: a smooth Maxwellian halo, a tidal stream and a
debris flow. In each case we use simulated directional data to attempt to
reconstruct the shape and parameters describing each model as well as the DM
particle properties. We find that the empirical parametrisation is able to make
accurate unbiased reconstructions of the DM mass and cross section as well as
capture features in the underlying velocity distribution in certain directions
without any assumptions about its true functional form. We also find that by
extracting directionally averaged velocity parameters with this method one can
discriminate between halo models with different classes of substructure.


title: Bilocal theory and gravity I

abstract:
  With the aim of investigating the relation between gravity and non-locality
at the classical level, we study a bilocal scalar field model. Bilocality
introduces new (internal) degrees of freedom that seem to reproduce gravity. We
show that the equations of motion of the massless branch of the free bilocal
model match those of linearized gravity. We also discuss higher orders of
perturbation theory, where there is self-interaction in both gravity and the
bilocal field sectors.


title: A marked correlation function for constraining modified gravity models

abstract:
  Future large scale structure surveys will provide increasingly tight
constraints on our cosmological model. These surveys will report results on the
distance scale and growth rate of perturbations through measurements of Baryon
Acoustic Oscillations and Redshift-Space Distortions. It is interesting to ask:
what further analyses should become routine, so as to test as-yet-unknown
models of cosmic acceleration? Models which aim to explain the accelerated
expansion rate of the Universe by modifications to General Relativity often
invoke screening mechanisms which can imprint a non-standard density dependence
on their predictions. This suggests density-dependent clustering as a `generic'
constraint. This paper argues that a density-marked correlation function
provides a density-dependent statistic which is easy to compute and report and
requires minimal additional infrastructure beyond what is routinely available
to such survey analyses. We give one realization of this idea and study it
using low order perturbation theory. We encourage groups developing modified
gravity theories to see whether such statistics provide discriminatory power
for their models.


title: Exoplanet Orbital Eccentricities Derived From LAMOST-Kepler Analysis

abstract:
  The nearly circular (mean eccentricity <e>~0.06) and coplanar (mean mutual
inclination <i>~3 deg) orbits of the Solar System planets motivated Kant and
Laplace to put forth the hypothesis that planets are formed in disks, which has
developed into the widely accepted theory of planet formation. Surprisingly,
the first several hundred extrasolar planets (mostly Jovian) discovered using
the Radial Velocity (RV) technique are commonly on eccentric orbits (<e> ~
0.3). This raises a fundamental question: Are the Solar System and its
formation special? The Kepler mission has found thousands of transiting planets
dominated by sub-Neptunes, but most of their orbital eccentricities remain
unknown. By using the precise spectroscopic host star parameters from the
LAMOST observations, we measure the eccentricity distributions for a large
(698) and homogeneous Kepler planet sample with transit duration statistics.
Nearly half of the planets are in systems with single transiting planets
(singles), while the other half are multiple-transiting planets (multiples). We
find an eccentricity dichotomy: on average, Kepler singles are on eccentric
orbits with <e>~0.3, while the multiples are on nearly circular (<e> =
0.04^{+0.03}_{-0.04}) and coplanar (<i> = 1.4^{+0.8}_{-1.1} deg) orbits similar
to the Solar System planets. Our results are consistent with previous studies
of smaller samples and individual systems. We also show that Kepler multiples
and solar system objects follow a common relation <e>~(1-2)x<i> between mean
eccentricities and mutual inclinations. The prevalence of circular orbits and
the common relation may imply that the solar system is not so atypical in the
galaxy after all.


title: Global Instability of Exo-Moon System Triggered by Photo-Evaporation

abstract:
  Many exoplanets have been found in orbits close to their host stars and thus
they are subject to the effects of photo-evaporation. Previous studies have
shown that a large portion of exoplanets detected by the Kepler mission have
been significantly eroded by photo-evaporation. In this paper, we numerically
study the effects of photo-evaporation on the orbital evolution of a
hypothesized moon system around a planet. We find that photo-evaporation is
crucial to the stability of the moon system. Photo-evaporation can erode the
atmosphere of the planet thus leading to significant mass loss. As the planet
loses mass, its Hill radius shrinks and its moons increase their orbital
semi-major axes and eccentricities. When some moons approach their critical
semi-major axes, global instability of the moon system would be triggered,
which usually ends up with two, one or even zero surviving moons. Some lost
moons could escape from the moon system to become a new planet orbiting the
star or run away further to become a free-floating object in the Galaxy. Given
the destructive role of photo-evaporation, we speculate that exo-moons are less
common for close-in planets ($<0.1$ AU), especially those around M-type stars,
because they are more X-ray luminous and thus enhancing photo-evaporation. The
lessons we learn in this study may be helpful for the target selection of
on-going/future exomoon searching programs.


title: The Fate of Debris in the Pluto-Charon System

abstract:
  The Pluto-Charon system has come into sharper focus following the fly by of
New Horizons. We use N-body simulations to probe the unique dynamical history
of this binary dwarf planet system. We follow the evolution of the debris disc
that might have formed during the Charon-forming giant impact. First, we note
that in-situ formation of the four circumbinary moons is extremely difficult if
Charon undergoes eccentric tidal evolution. We track collisions of disc debris
with Charon, estimating that hundreds to hundreds of thousands of visible
craters might arise from 0.3--5 km radius bodies. New Horizons data suggesting
a dearth of these small craters may place constraints on the disc properties.
While tidal heating will erase some of the cratering history, both tidal and
radiogenic heating may also make it possible to differentiate disc debris
craters from Kuiper belt object craters. We also track the debris ejected from
the Pluto-Charon system into the Solar System; while most of this debris is
ultimately lost from the Solar System, a few tens of 10--30 km radius bodies
could survive as a Pluto-Charon collisional family. Most are plutinos in the
3:2 resonance with Neptune, while a small number populate nearby resonances. We
show that migration of the giant planets early in the Solar System's history
would not destroy this collisional family. Finally, we suggest that
identification of such a family would likely need to be based on composition as
they show minimal clustering in relevant orbital parameters.


title:
Asymmetric Orbital Distribution near Mean Motion Resonance: Application
  to Planets Observed by Kepler and Radial Velocities

abstract:
  Many multiple-planet systems have been found by the Kepler transit survey and
various radial velocity (RV) surveys. Kepler planets show an asymmetric
feature, namely, there are small but significant deficits/excesses of planet
pairs with orbital period spacing slightly narrow/wide of the exact resonance,
particularly near the first order mean motion resonance (MMR), such as 2:1 and
3:2 MMR. Similarly, if not exactly the same, an asymmetric feature (pileup wide
of 2:1 MMR) is also seen in RV planets, but only for massive ones. We
analytically and numerically study planets' orbital evolutions near and in the
MMR. We find that their orbital period ratios could be asymmetrically
distributed around the MMR center regardless of dissipation. In the case of no
dissipation, Kepler planets' asymmetric orbital distribution could be partly
reproduced for 3:2 MMR but not for 2:1 MMR, implying that dissipation might be
more important to the latter. The pileup of massive RV planets just wide of 2:1
MMR is found to be consistent with the scenario that planets formed separately
then migrated toward the MMR. The location of the pileup infers a K value of
1-100 on the order of magnitude for massive planets, where K is the damping
rate ratio between orbital eccentricity and semimajor axis during planet
migration.


title: Non-Unitarity, sterile neutrinos, and Non-Standard neutrino Interactions

abstract:
  The simplest Standard Model extension to explain neutrino masses involves the
addition of right-handed neutrinos. At some level, this extension will impact
neutrino oscillation searches. In this work we explore the differences and
similarities between the case in which these neutrinos are kinematically
accessible (sterile neutrinos) or not (mixing matrix non-unitarity). We clarify
apparent inconsistencies in the present literature when using different
parametrizations to describe these effects and recast both limits in the
popular neutrino non-standard interaction (NSI) formalism. We find that, in the
limit in which sterile oscillations are averaged out at the near detector,
their effects at the far detector coincide with non-unitarity at leading order,
even in presence of a matter potential. We also summarize the present bounds
existing in both limits and compare them with the expected sensitivities of
near future facilities taking the DUNE proposal as a benchmark. We conclude
that non-unitarity effects are too constrained to impact present or near future
neutrino oscillation facilities but that sterile neutrinos can play an
important role at long baseline experiments. The role of the near detector is
also discussed in detail.


title: Ultraviolet and X-ray variability of active galactic nuclei with Swift

abstract:
  We analyse a sample of 21 active galactic nuclei (AGN) using data from the
Swift satellite to study the variability properties of the population in the
X-ray, UV and optical band. We find that the variable part of the UV-optical
emission has a spectrum consistent with a powerlaw, with an average index of
$-2.21\pm0.13$, as would be expected from central illumination of a thin disc
(index of -7/3). We also calculate the slope of a powerlaw from UV to X-ray
variable emission, $\alpha_{\rm OX,Var}$; the average for this sample is
$\alpha_{\rm OX,Var} = -1.06 \pm 0.04$. The anticorrelation of $\alpha_{\rm
OX}$ with the UV luminosity, $L_{\rm UV}$, previously found in the average
emission is also present in the variable part: $\alpha_{\rm OX,Var} = (-0.177
\pm 0.083) {\rm log} (L_{\rm \nu,Var} (2500\,\AA)) + (3.88 \pm 2.33)$.
Correlated variability between the emission in X-rays and UV is detected
significantly for 9 of the 21 sources. All these cases are consistent with the
UV lagging the X-rays, as would be seen if the correlated UV variations were
produced by the reprocessing of X-ray emission. The observed UV lags are
tentatively longer than expected for a standard thin disc.


title:
Phase diagram and correlation functions of the anisotropic imperfect
  Bose gas in $d$ dimensions

abstract:
  We study an anisotropic variant of the $d$-dimensional imperfect Bose gas,
where the asymptotic behaviour of the dispersion $\epsilon_{\bf k}$ at
vanishing momentum $\bf{k}$ may differ from the standard quadratic form. The
analysis reveals the key role of the shift exponent $\psi$ governing the
asymptotic behaviour of the critical temperature $T_c(\mu)$ as a function of
the chemical potential $\mu$ at $T_c\to 0$. We argue that the universality
classes of Bose-Einstein condensation admitted by the model may be classified
according to the allowed values of $\psi$ so that spatial dimensionality has
only an indirect impact on the transition properties. We analyse the
correlation function of the model and discuss its asymptotics depending on the
direction. Both for the perfect and imperfect anisotropic Bose gases, the
correlation function $\chi({\bf x})$ at $T>T_c$ turns out to show either
exponential decay or exponentially damped oscillatory behaviour depending on
the orientation of ${\bf x}$ with respect to the dispersion anisotropies.

categories: cond-mat.stat-mech cond-mat.quant-gas math-ph math.MP


title:
Relation between proton decay and PMNS phase in the minimal SUSY
  $SO(10)$ GUT

abstract:
  Proton decay is one of the most important predictions of the grand unified
theory (GUT). In the supersymmetric (SUSY) GUT, proton decays via the
dimension-five operators need to be suppressed. In the $SO(10)$ model where
${\bf 10}+\overline{\bf 126}$ Higgs fields couple to fermions, neutrino
oscillation parameters including the CP-violating
Pontecorvo-Maki-Nakagawa-Sakata (PMNS) phase can be related to the Yukawa
couplings to generate the dimension-five operators in the unified framework. We
show how the suppressed proton decay depends on the PMNS phase, and stress the
importance of the precise measurements of the PMNS phase as well as the
neutrino 23-mixing angle. These become especially important if the SUSY
particles are found around less than a few TeV at LHC and proton decays are
observed at Hyper-Kamiokande and DUNE experiments in the near future.


title:
Graphical modelling of multivariate spatial point processes with
  continuous marks

abstract:
  This paper is the second in a series of papers which combine graphical
modelling and marked spatial point patterns. Extending the previous results of
\cite Eckardt (2016a), we introduce a marked spatial dependence graph model
which depicts the global dependence structure of quantitatively marked
multi-type points that occur in space based on the marked conditional partial
spectral coherence. Most beneficial, no structural assumption with respect to
the characteristics in the data are to be made prior to analysis. This approach
presents a computationally efficient method of pattern recognition in highly
structured and high dimensional multi-type spatial point processes where also
quantitative marks are available. Unlike all previous methods, our new model
permits the simultaneous analysis of all multivariate conditional
interrelations. The new technique is illustrated analysing the diameter at
breast hight of 37 different tree species recorded at 10053 locations in Duke
Forest.


title: Benchmarking the Graphulo Processing Framework

abstract:
  Graph algorithms have wide applicablity to a variety of domains and are often
used on massive datasets. Recent standardization efforts such as the GraphBLAS
specify a set of key computational kernels that hardware and software
developers can adhere to. Graphulo is a processing framework that enables
GraphBLAS kernels in the Apache Accumulo database. In our previous work, we
have demonstrated a core Graphulo operation called \textit{TableMult} that
performs large-scale multiplication operations of database tables. In this
article, we present the results of scaling the Graphulo engine to larger
problems and scalablity when a greater number of resources is used.
Specifically, we present two experiments that demonstrate Graphulo scaling
performance is linear with the number of available resources. The first
experiment demonstrates cluster processing rates through Graphulo's TableMult
operator on two large graphs, scaled between $2^{17}$ and $2^{19}$ vertices.
The second experiment uses TableMult to extract a random set of rows from a
large graph ($2^{19}$ nodes) to simulate a cued graph analytic. These
benchmarking results are of relevance to Graphulo users who wish to apply
Graphulo to their graph problems.


title:
The Herschel Exploitation of Local Galaxy Andromeda (HELGA) VII: A SKIRT
  radiative transfer model and insights on dust heating

abstract:
  The radiation of stars heats dust grains in the diffuse interstellar medium
and in star-forming regions in galaxies. Modelling this interaction provides
information on dust in galaxies, a vital ingredient for their evolution. It is
not straightforward to identify the stellar populations heating the dust, and
to link attenuation to emission on a sub-galactic scale. Radiative transfer
models are able to simulate this dust-starlight interaction in a realistic,
three-dimensional setting. We investigate the dust heating mechanisms on a
local and global galactic scale, using the Andromeda galaxy (M31) as our
laboratory. We perform a series of panchromatic radiative transfer simulations
of Andromeda with our code SKIRT. The high inclination angle of M31 complicates
the 3D modelling and causes projection effects. However, the observed
morphology and flux density are reproduced fairly well from UV to
sub-millimeter wavelengths. Our model reveals a realistic attenuation curve,
compatible with previous, observational estimates. We find that the dust in M31
is mainly (91 % of the absorbed luminosity) heated by the evolved stellar
populations. The bright bulge produces a strong radiation field and induces
non-local heating up to the main star-forming ring at 10 kpc. The relative
contribution of unevolved stellar populations to the dust heating varies
strongly with wavelength and with galactocentric distance.The dust heating
fraction of unevolved stellar populations correlates strongly with NUV-r colour
and specific star formation rate. These two related parameters are promising
probes for the dust heating sources at a local scale.


title: Scalar field dark matter in clusters of galaxies

abstract:
  One alternative to the cold dark matter (CDM) paradigm is the scalar field
dark matter (SFDM) model, which assumes dark matter is a spin-0 ultra-light
scalar field (SF) with a typical mass $m\sim10^{-22}\mathrm{eV}/c^2$ and
positive self-interactions. Due to the ultra-light boson mass, the SFDM could
form Bose-Einstein condensates (BEC) in the very early Universe, which are
interpreted as the dark matter haloes. Although cosmologically the model
behaves as CDM, they differ at small scales: SFDM naturally predicts fewer
satellite haloes, cores in dwarf galaxies and the formation of massive galaxies
at high redshifts. The ground state (or BEC) solution at zero temperature
suffices to describe low-mass galaxies but fails for larger systems. A possible
solution is adding finite-temperature corrections to the SF potential which
allows combinations of excited states. In this work, we test the
finite-temperature multistate SFDM solution at galaxy cluster scales and
compare our results with the Navarro-Frenk-White (NFW) and BEC profiles. We
achieve this by fitting the mass distribution of 13 \textit{Chandra} X-ray
clusters of galaxies, excluding the region of the brightest cluster galaxy. We
show that the SFDM model accurately describes the clusters' DM mass
distributions offering an equivalent or better agreement than the NFW profile.
The complete disagreement of the BEC model with the data is also shown. We
conclude that the theoretically motivated multistate SFDM profile is an
interesting alternative to empirical profiles and ad hoc fitting-functions that
attempt to couple the asymptotic NFW decline with the inner core in SFDM.


title: Colouring squares of claw-free graphs

abstract:
  Is there some absolute $\varepsilon > 0$ such that for any claw-free graph
$G$, the chromatic number of the square of $G$ satisfies $\chi(G^2) \le
(2-\varepsilon) \omega(G)^2$, where $\omega(G)$ is the clique number of $G$?
Erd\H{o}s and Ne\v{s}et\v{r}il asked this question for the specific case of $G$
the line graph of a simple graph and this was answered in the affirmative by
Molloy and Reed. We show that the answer to the more general question is also
yes, and moreover that it essentially reduces to the original question of
Erd\H{o}s and Ne\v{s}et\v{r}il.


title: Squared chromatic number without claws or large cliques

abstract:
  Let $G$ be a claw-free graph on $n$ vertices with clique number $\omega$, and
consider the chromatic number $\chi(G^2)$ of the square $G^2$ of $G$. Writing
$\chi'_s(d)$ for the supremum of $\chi(L^2)$ over the line graphs $L$ of simple
graphs of maximum degree at most $d$, we prove that $\chi(G^2)\le
\chi'_s(\omega)$ for $\omega \in \{3,4\}$. For $\omega=3$, this implies the
sharp bound $\chi(G^2) \leq 10$. For $\omega=4$, this implies $\chi(G^2)\leq
22$, which is within $2$ of the conjectured best bound. This work is motivated
by a strengthened form of a conjecture of Erd\H{o}s and Ne\v{s}et\v{r}il.


title: Voigt transformations in retrospect: missed opportunities?

abstract:
  The teaching of modern physics often uses the history of physics as a
didactic tool. However, as in this process the history of physics is not
something studied but used, there is a danger that the history itself will be
distorted in, as Butterfield calls it, a "Whiggish" way, when the present
becomes the measure of the past. It is not surprising that reading today a
paper written more than a hundred years ago, we can extract much more of it
than was actually thought or dreamed by the author himself. We demonstrate this
Whiggish approach on the example of Woldemar Voigt's 1887 paper. From the
modern perspective, it may appear that this paper opens a way to both the
special relativity and to its anisotropic Finslerian generalization which came
into the focus only recently, in relation with the Cohen and Glashow's very
special relativity proposal. With a little imagination, one can connect Voigt's
paper to the notorious Einstein-Poincare priority dispute, which we believe is
a Whiggish late time artifact. We use the related historical circumstances to
give a broader view on special relativity, than it is usually anticipated.


title:
Negative curves on symmetric blowups of the projective plane,
  resurgences and Waldschmidt constants

abstract:
  The Klein and Wiman configurations are highly symmetric configurations of
lines in the projective plane arising from complex reflection groups. One
noteworthy property of these configurations is that all the singularities of
the configuration have multiplicity at least three. In this paper we study the
surface X obtained by blowing up the projective plane in the singular points of
one of these line configurations. We study invariant curves on X in detail,
with a particular emphasis on curves of negative self-intersection. We use the
representation theory of the stabilizers of the singular points to discover
several invariant curves of negative self-intersection on X, and use these
curves to study Nagata-type questions for linear series on X.
  The homogeneous ideal I of the collection of points in the configuration is
an example of an ideal where the symbolic cube of the ideal is not contained in
the square of the ideal; ideals with this property are seemingly quite rare.
The resurgence and asymptotic resurgence are invariants which were introduced
to measure such failures of containment. We use our knowledge of negative
curves on X to compute the resurgence of I exactly. We also compute the
asymptotic resurgence and Waldschmidt constant exactly in the case of the Wiman
configuration of lines, and provide estimates on both for the Klein
configuration.


title: Projective Curvature Tensors of Second Type Almost Geodesic Mappings

abstract:
  We consider equitorsion second type almost geodesic mappings of a
non-symmetric affine connection space in this article. Using different
computational methods, we obtained some invariants of these mappings. Last
generalized Thomas projective parameter and Weyl projective tensor as
invariants of a second type almost geodesic mapping of a non-symmetric affine
connection space are further generalized here.


title:
Detection of Faults in Power System Using Wavelet Transform and
  Independent Component Analysis

abstract:
  Uninterruptible power supply is the main motive of power utility companies
that motivate them for identifying and locating the different types of faults
as quickly as possible to protect the power system prevent complete power black
outs using intelligent techniques. Thus, the present research work presents a
novel method for detection of fault disturbances based on Wavelet Transform
(WT) and Independent Component Analysis (ICA). The voltage signal is taken
offline under fault conditions and is being processed through wavelet and ICA
for detection. The time-frequency resolution from WT transform detects the
fault initiation instant in the signal. Again, a performance index is
calculated from independent component analysis under fault condition which is
used to detect the fault disturbance in the voltage signal. The proposed
approach is tested to be robust enough under various operating scenarios like
without noise, with 20-dB noise and variation in frequency. Further, the
detection study is carried out using a performance index, energy content, by
applying the existing Fourier transform (FT), short time Fourier transform
(STFT) and the proposed wavelet transform. Fault disturbances are detected if
the energy calculated in each scenario is greater than the corresponding
threshold value. The fault detection study is simulated in MATLAB/Simulink for
a typical power system.


title:
Strain-dependent internal parameters in hyperelastic biological
  materials

abstract:
  The behavior of hyperelastic energies depending on an internal parameter,
which is a function of the deformation gradient, is discussed. As an example,
the analysis of two models where the parameter describes the activation of a
tetanized skeletal muscle tissue is presented. In those models, the activation
parameter depends on the strain and it is shown the importance of considering
the derivative of the parameter with respect to the strain in order to capture
the proper stress-strain relations.


title:
Thermodynamics of Giant Planet Formation: Shocking Hot Surfaces on
  Circumplanetary Disks

abstract:
  The luminosity of young giant planets can inform about their formation and
accretion history. The directly imaged planets detected so far are consistent
with the "hot-start" scenario of high entropy and luminosity. If nebular gas
passes through a shock front before being accreted into a protoplanet, the
entropy can be substantially altered. To investigate this, we present high
resolution, 3D radiative hydrodynamic simulations of accreting giant planets.
The accreted gas is found to fall with supersonic speed in the gap from the
circumstellar disk's upper layers onto the surface of the circumplanetary disk
and polar region of the protoplanet. There it shocks, creating an extended hot
supercritical shock surface. This shock front is optically thick, therefore, it
can conceal the planet's intrinsic luminosity beneath. The gas in the vertical
influx has high entropy which when passing through the shock front decreases
significantly while the gas becomes part of the disk and protoplanet. This
shows that circumplanetary disks play a key role in regulating a planet's
thermodynamic state. Our simulations furthermore indicate that around the shock
surface extended regions of atomic - sometimes ionized - hydrogen develop.
Therefore circumplanetary disk shock surfaces could influence significantly the
observational appearance of forming gas-giants.


title:
Predictions for the detection of Tidal Streams with Gaia using Great
  Circle Methods

abstract:
  The Gaia astrometric mission may offer an unprecedented opportunity to
discover new tidal streams in the Galactic halo. To test this, we apply nGC3, a
great-circle-cell count method that combines position and proper motion data to
identify streams, to ten mock Gaia catalogues of K giants and RR Lyrae stars
constructed from cosmological simulations of Milky Way analogues. We analyse
two sets of simulations, one using a combination of $N$-body and
semi-analytical methods which has extremely high resolution, the other using
hydro-dynamical methods, which captures the dynamics of baryons, including the
formation of an in situ halo. These ten realisations of plausible Galactic
merger histories allow us to assess the potential for the recovery of tidal
streams in different Milky Way formation scenarios. We include the
Gaia~selection function and observational errors in these mock catalogues. We
find that the nGC3 method has a well-defined detection boundary in the space of
stream width and projected overdensity, that can be predicted based on direct
observables alone. We predict that about 4-13 dwarf galaxy streams can be
detected in a typical Milky Way-mass halo with Gaia+nGC3, with an estimated
efficiency of $>$80\% inside the detection boundary. The progenitors of these
streams are in the mass range of the classical dwarf galaxies and may have been
accreted as early as redshift $\sim3$. Finally, we analyse how different
possible extensions of the Gaia mission will improve the detection of tidal
streams.


title: Spin equilibrium in strongly-magnetized accreting stars

abstract:
  Strongly magnetized accreting stars are often hypothesized to be in `spin
equilibrium' with their surrounding accretion flows, which requires that the
accretion rate changes more slowly than it takes the star to reach spin
equilibrium. This is not true for most magnetically accreting stars, which have
strongly variable accretion outbursts on time-scales much shorter than the time
it would take to reach spin equilibrium. This paper examines how accretion
outbursts affect the time a star takes to reach spin equilibrium and its final
equilibrium spin period. I consider several different models for angular
momentum loss -- either carried away in an outflow, lost to a stellar wind, or
transferred back to the accretion disc (the `trapped disc'). For transient
sources, the outflow scenario leads to significantly longer times to reach spin
equilibrium ($\sim$10x), and shorter equilibrium spin periods than would be
expected from spin equilibrium arguments, while the `trapped disc' does not.
The results suggest that disc trapping plays a significant role in the spin
evolution of strongly magnetic stars, with some caveats for young stellar
objects.


title: An empirical analysis of the Ebola outbreak in West Africa

abstract:
  The data for the Ebola outbreak that occurred in 2014-2016 in three countries
of West Africa are analysed within a common framework. The analysis is made
using the results of an agent based Susceptible-Infected-Removed (SIR) model on
a Euclidean network, where nodes at a distance $l$ are connected with
probability $P(l) \propto l^{-\delta }$, $\delta$ determining the range of the
interaction, in addition to nearest neighbors. The cumulative (total) density
of infected population here has the form $R(t) =
\frac{a\exp(t/T)}{1+c\exp(t/T)}$, where the parameters depend on $\delta$ and
the infection probability $q$. This form is seen to fit well with the data.
Using the best fitting parameters, the time at which the peak is reached is
estimated and is shown to be consistent with the data. We also show that in the
Euclidean model, one can choose $\delta$ and $q$ values which reproduce the
data for the three countries qualitatively. These choices are correlated with
population density, control schemes and other factors. Comparing the real data
and the results from the model one can also estimate the size of the actual
population susceptible to the disease. Rescaling the real data a reasonably
good quantitative agreement with the simulation results is obtained.


title:
Efficient Offline Waveform Design Using Quincunx/Hexagonal
  Time-Frequency Lattices For 5G Systems

abstract:
  Conventional OFDM, adopted in LTE-A systems, cannot provide the quality of
service requirements sought in 5G systems because of extreme natural channel
impairments caused by higher Doppler spreads and unexpected artificial
impairments caused by multi-source transmission, to be brought by 5G, and by
synchronization relaxation for closed-loop signaling overhead reduction in some
5G applications. These severe impairments induce a strong loss of orthogonality
between subcarriers and OFDM symbols and, therefore, lead to a dramatic
increase in ICI and ISI. To be well armed against these dramatic impairments,
we, in the present paper, optimize the transmit/receive waveforms for FBMC
systems, with hexagonal time-frequency lattices, operating over severe doubly
dispersive channels, accounting for both natural and artificial impairments.
For this, we exploit the POPS paradigm, recently proposed for rectangular
time-frequency lattices, to design offline waveforms maximizing the SINR for
hexagonal time-frequency lattices. We show that FBMC, with hexagonal lattices,
offers a strong improvement in SIR with respect to conventional OFDM and an
improvement of 1dB with respect to POPS-FBMC, with classical rectangular
lattices. Furthermore, we show that the hexagonal POPS-FBMC brings more
robustness to frequency synchronization errors and offers a 10dB reduction in
OOB emissions with respect to rectangular POPS-FBMC.


title: Enhanced Dynamical Stability with Harmonic Slip-stacking

abstract:
  We develop a configuration of radio-frequency (rf) cavities to dramatically
improve the performance of slip-stacking. Slip-stacking is an accumulation
technique used at Fermilab to nearly double proton intensity by maintaining two
beams of different momenta in the same storage ring. The two particle beams are
longitudinally focused in the Recycler by two 53 MHz 100 kV rf cavities with a
small frequency difference between them. We propose an additional 106 MHz 20 kV
rf cavity with a frequency at the double the average of the upper and lower
main rf frequencies. We show the harmonic rf cavity cancels out the resonances
generated between the two main rf cavities and we derive the relationship
between the harmonic rf voltage and the main rf voltage. We find the area
factors that can be used to calculate the available phase space area for any
set of beam parameters without individual simulation. We establish Booster beam
quality requirements to achieve 99\% slip-stacking efficiency. We measure the
longitudinal distribution of the Booster beam and use it to generate a
realistic beam model for slip-stacking simulation. We demonstrate that the
harmonic rf cavity can not only reduce particle loss during slip-stacking, but
also reduce the final longitudinal emittance.


title: J-Frame Sequences in Krein Space

abstract:
  Let $\{f_n:n\in\mathbb{N}\}$ be a $J$-frame for a Krein space
${\textbf{\textit{K}}}$ and $P_M$ be a $J$-orthogonal projection from
${\textbf{\textit{K}}}$ onto a subspace $M$. In this article we find sufficient
conditions under which $\{P_M(f_n):n\in\mathbb{N}\}$ is a $J$-frame for
$P_M\textbf{\textit{K}}$ and $\{(I-P_M)f_n\}_{n\in{\mathbb{N}}}$ is a $J$-frame
for $(I-P_M)\textbf{\textit{K}}$. We also introduce $J$-frame sequence for a
Krein space ${\textbf{\textit{K}}}$ and study some properties of $J$-frame
sequence analogues to Hilbert space frame theory.


title: Tight J-frames in Krein space and the associated J-frame potential

abstract:
  Motivated by the idea of $J$-frame for a Krein space $\textbf{\textit{K}}$,
introduced by Giribet \textit{et al.} (J. I. Giribet, A. Maestripieri, F.
Mart\'inez Per\'{i}a, P. G. Massey, \textit{On frames for Krein spaces}, J.
Math. Anal. Appl. (1), {\bf 393} (2012), 122--137.), we introduce the notion of
$\zeta-J$-tight frame for a Krein space $\textbf{\textit{K}}$. In this paper we
characterize $J$-orthonormal basis for $\textbf{\textit{K}}$ in terms of
$\zeta-J$-Parseval frame. We show that a Krein space is richly supplied with
$\zeta-J$-Parseval frames. We also provide a necessary and sufficient condition
when the linear sum of two $\zeta-J$-Parseval frames is again a
$\zeta-J$-Parseval frame. We then generalize the notion of $J$-frame potential
in Krein space from Hilbert space frame theory. Finally we provided a necessary
and sufficient condition for a $J$-frame potential of the corresponding
$\zeta-J$-tight frame to be minimum.


title:
The Role of Star-Formation and AGN in Dust Heating of z=0.3-2.8 Galaxies
  - II. Informing IR AGN fraction estimates through simulations

abstract:
  A key question in extragalactic studies is the determination of the relative
roles of stars and AGN in powering dusty galaxies at $z\sim$1-3 where the bulk
of star-formation and AGN activity took place. In Paper I, we present a sample
of $336$ 24$\mu$m-selected (Ultra)Luminous Infrared Galaxies, (U)LIRGs, at $z
\sim 0.3$-$2.8$, where we focus on determining the AGN contribution to the IR
luminosity. Here, we use hydrodynamic simulations with dust radiative transfer
of isolated and merging galaxies, to investigate how well the simulations
reproduce our empirical IR AGN fraction estimates and determine how IR AGN
fractions relate to the UV-mm AGN fraction. We find that: 1) IR AGN fraction
estimates based on simulations are in qualitative agreement with the empirical
values when host reprocessing of the AGN light is considered; 2) for
star-forming galaxy-AGN composites our empirical methods may be underestimating
the role of AGN, as our simulations imply $>$50% AGN fractions, $\sim$3$\times$
higher than previous estimates; 3) 6% of our empirically classified "SFG" have
AGN fractions $\gtrsim$50%. While this is a small percentage of SFGs, if
confirmed, would imply the true number density of AGN may be underestimated; 4)
this comparison depends on the adopted AGN template -- those that neglect the
contribution of warm dust lower the empirical fractions by up to 2$\times$; and
5) the IR AGN fraction is only a good proxy for the intrinsic UV-mm AGN
fraction when the extinction is high ($A_V\gtrsim 1$ or up to and including
coalescence in a merger).


title: Task Specific Adversarial Cost Function

abstract:
  The cost function used to train a generative model should fit the purpose of
the model. If the model is intended for tasks such as generating perceptually
correct samples, it is beneficial to maximise the likelihood of a sample drawn
from the model, Q, coming from the same distribution as the training data, P.
This is equivalent to minimising the Kullback-Leibler (KL) distance, KL[Q||P].
However, if the model is intended for tasks such as retrieval or classification
it is beneficial to maximise the likelihood that a sample drawn from the
training data is captured by the model, equivalent to minimising KL[P||Q]. The
cost function used in adversarial training optimises the Jensen-Shannon entropy
which can be seen as an even interpolation between KL[Q||P] and KL[P||Q]. Here,
we propose an alternative adversarial cost function which allows easy tuning of
the model for either task. Our task specific cost function is evaluated on a
dataset of hand-written characters in the following tasks: Generation,
retrieval and one-shot learning.


title:
Inverted anisotropy in the in-plane dissipation of BSCCO tapes:
  preliminary results

abstract:
  The electrical properties of superconducting tapes and coatings in the
direction transverse to the long dimension of the composite has been rarely
studied. However, transverse dissipation can eventually determine the behavior
of a transmission line in the case of failure due to the presence of
transversal cracks, and is also fundamental in the AC regime. In this paper we
present a preliminary experimental study of the electrical transport properties
along the transverse direction of BSCCO-metal tapes, and compare them with
those measured along the long axis of the material. In spite of the fact that
the tapes under study are not multi-filamentary, our experiments suggest that
there is a measurable anisotropy of the transport properties between the
longitudinal and transverse directions.


title: Learning Genomic Representations to Predict Clinical Outcomes in Cancer

abstract:
  Genomics are rapidly transforming medical practice and basic biomedical
research, providing insights into disease mechanisms and improving therapeutic
strategies, particularly in cancer. The ability to predict the future course of
a patient's disease from high-dimensional genomic profiling will be essential
in realizing the promise of genomic medicine, but presents significant
challenges for state-of-the-art survival analysis methods. In this abstract we
present an investigation in learning genomic representations with neural
networks to predict patient survival in cancer. We demonstrate the advantages
of this approach over existing survival analysis methods using brain tumor
data.


title: Universal hierarchical structure of quasiperiodic eigenfunctions

abstract:
  We determine exact exponential asymptotics of eigenfunctions and of
corresponding transfer matrices of the almost Mathieu operators for all
frequencies in the localization regime. This uncovers a universal structure in
their behavior, governed by the continued fraction expansion of the frequency,
explaining some predictions in physics literature.
  In addition it proves the arithmetic version of the frequency transition
conjecture. Finally, it leads to an explicit description of several
non-regularity phenomena in the corresponding non-uniformly hyperbolic
cocycles, which is also of interest as both the first natural example of some
of those phenomena and, more generally, the first non-artificial model where
non-regularity can be explicitly studied.


title:
A Bayesian Risk Approach to Data-driven Stochastic Optimization:
  Formulations and Asymptotics

abstract:
  A large class of stochastic programs involve optimizing an expectation taken
with respect to an underlying distribution that is unknown in practice. One
popular approach to addressing the distributional uncertainty, known as the
distributionally robust optimization (DRO), is to hedge against the worst case
over an uncertainty set of candidate distributions. However, it has been
observed that inappropriate construction of the uncertainty set can sometimes
result in over-conservative solutions. To explore the middle ground between
optimistically ignoring the distributional uncertainty and pessimistically
fixating on the worst-case scenario, we propose a Bayesian risk optimization
(BRO) framework for parametric underlying distributions, which is to optimize a
risk functional applied to the posterior distribution of an unknown
distribution parameter. Of our particular interest are four risk functionals:
mean, mean-variance, value-at-risk, and conditional value-at-risk. To unravel
the implication of BRO, we establish the consistency of objective functions and
optimal solutions, as well as the asymptotic normality of objective functions
and optimal values. More importantly, our analysis reveals a hidden
interpretation: the objectives of BRO can be approximately viewed as a weighted
sum of posterior mean objective and the (squared) half-width of the true
objective's confidence interval.


title:
Low and High Energy Asymptotic Behavior of Electroweak Corrections in
  Polarized $e^+ e^- \to \mu^+ \mu^-$ Process

abstract:
  Electroweak radiative corrections will play a major role in the analysis of
several upcoming ultra-precision experiments such as Belle-II, so is crucial to
make sure that they are fully under control. The article outlines the recent
developments in the theoretical and computational approaches to one-loop (NLO)
electroweak radiative corrections to the parity-violating asymmetry in $e^- e^+
\to \mu^- \mu^+ (\gamma)$ process with longitudinally polarized electrons. We
derive asymptotic expressions for low and high energy regions (well below or
above $Z$-resonance, correspondingly) and analyze the leading contributions.
For most of energy regions, our results are in good agreement with precise
computer-algebra based calculation and can used as a quicker alternative.


title: Deep Reinforcement Learning for Mention-Ranking Coreference Models

abstract:
  Coreference resolution systems are typically trained with heuristic loss
functions that require careful tuning. In this paper we instead apply
reinforcement learning to directly optimize a neural mention-ranking model for
coreference evaluation metrics. We experiment with two approaches: the
REINFORCE policy gradient algorithm and a reward-rescaled max-margin objective.
We find the latter to be more effective, resulting in significant improvements
over the current state-of-the-art on the English and Chinese portions of the
CoNLL 2012 Shared Task.


title:
Singular elliptic equation involving the GJMS operator on the standard
  unit sphere

abstract:
  Given a Riemannian compact manifold (M,g) of dimension n>4, we have proven in
[1] under some conditions that the equation : Pg(u) = Bu +Au2+Cu (1) where Pg
is the GJMS-operator, n = dim(M) > 2k, A, B and C are smooth positive functions
on M, p > 1 and 2] denotes the critical Sobolev admits twodistinct positive
solutions. The proof of this result is essentially based on the given smooth
function ' > 0 with norm k'kPg = 1 fulfilling some conditions ( see Theorem 3
in [1]). In this note we construct an example of such function on the unit
standard sphere (Sn; h). Con- sequently the conditions of the Theorem are
improved in the case of (Sn; h)


title: A Transportation $L^p$ Distance for Signal Analysis

abstract:
  Transport based distances, such as the Wasserstein distance and earth mover's
distance, have been shown to be an effective tool in signal and image analysis.
The success of transport based distances is in part due to their Lagrangian
nature which allows it to capture the important variations in many signal
classes. However these distances require the signal to be nonnegative and
normalized. Furthermore, the signals are considered as measures and compared by
redistributing (transporting) them, which does not directly take into account
the signal intensity. Here we study a transport-based distance, called the
$TL^p$ distance, that combines Lagrangian and intensity modelling and is
directly applicable to general, non-positive and multi-channelled signals. The
framework allows the application of existing numerical methods. We give an
overview of the basic properties of this distance and applications to
classification, with multi-channelled, non-positive one and two-dimensional
signals, and color transfer.


title:
Linear nonlocal problem for the abstract time-dependent non-homogeneous
  Schr\"odinger equation

abstract:
  A nonlocal-in-time problem for the abstract Schr\"odinger equation is
considered. By exploiting the linear nature of nonlocal condition we derive an
exact representation of the solution operator under assumptions that the
spectrum of Hamiltonian is contained in the horizontal strip of complex plane.
The derived representation permits us to establish the necessary and sufficient
conditions for the problem's well-posedness and the existence of its mild,
strong solutions. Furthermore, we present new sufficient conditions for the
existence of solution which extend the available results to the case when some
nonlocal parameters are unbounded. Two examples are provided.

categories: math-ph math.DS math.FA math.MP quant-ph


title:
H.E.S.S. observations of RX J1713.7-3946 with improved angular and
  spectral resolution; evidence for gamma-ray emission extending beyond the
  X-ray emitting shell

abstract:
  Supernova remnants exhibit shock fronts (shells) that can accelerate charged
particles up to very high energies. In the past decade, measurements of a
handful of shell-type supernova remnants in very-high-energy gamma rays have
provided unique insights into the acceleration process. Among those objects,
RX$~$J1713.7-3946 (also known as G347.3-0.5) has the largest surface
brightness, allowing us in the past to perform the most comprehensive study of
morphology and spatially resolved spectra of any such very-high-energy
gamma-ray source. Here we present extensive new H.E.S.S. measurements of
RX$~$J1713.7-3946, almost doubling the observation time compared to our
previous publication. Combined with new improved analysis tools, the previous
sensitivity is more than doubled. The H.E.S.S. angular resolution of
$0.048^\circ$ ($0.036^\circ$ above 2 TeV) is unprecedented in gamma-ray
astronomy and probes physical scales of 0.8 (0.6) parsec at the remnant's
location.
  The new H.E.S.S. image of RX$~$J1713.7-3946 allows us to reveal clear
morphological differences between X-rays and gamma rays. In particular, for the
outer edge of the brightest shell region, we find the first ever indication for
particles in the process of leaving the acceleration shock region. By studying
the broadband energy spectrum, we furthermore extract properties of the parent
particle populations, providing new input to the discussion of the leptonic or
hadronic nature of the gamma-ray emission mechanism.


title:
Stability in Burkholder's differentially subordinate martingales
  inequalities and applications to Fourier multipliers

abstract:
  We study stability estimates for the almost extremal functions associated
with the $L^p$-bound for the real and imaginary parts of the Beurling-Ahlfors
operator. The proof exploits probabilistic methods and rests on analogous
results for differentially subordinate martingales which are of independent
interest. This allows us to obtain stability inequalities for a larger class of
Fourier multipliers.


title: Unstable fronts and stable "critters" formed by microrollers

abstract:
  Condensation of objects into stable clusters occurs naturally in equilibrium
and driven systems. It is commonly held that potential interactions, depletion
forces, or sensing are the only mechanisms which can create long-lived compact
structures. Here we show that persistent motile structures can form
spontaneously from hydrodynamic interactions alone with no sensing or potential
interactions. We study this structure formation in a system of colloidal
rollers suspended and translating above a floor, using both experiments and
large-scale 3D simulations. In this system, clusters originate from a
previously unreported fingering instability, where fingers pinch off from an
unstable front to form autonomous "critters", whose size is selected by the
height of the particles above the floor. These critters are a stable state of
the system, move much faster than individual particles, and quickly respond to
a changing drive. With speed and direction set by a rotating magnetic field,
these active structures offer interesting possibilities for guided transport,
flow generation, and mixing at the microscale.


title:
Dynamically induced robust phonon transport and chiral cooling in an
  optomechanical system

abstract:
  The transport of sound and heat, in the form of phonons, can be limited by
disorder-induced scattering. In electronic and optical settings the
introduction of chiral transport, in which carrier propagation exhibits parity
asymmetry, can remove elastic backscattering and provides robustness against
disorder. However, suppression of disorder-induced scattering has never been
demonstrated in non-topological phononic systems. Here we experimentally
demonstrate a path for achieving robust phonon transport in the presence of
material disorder, by explicitly inducing chirality through parity-selective
optomechanical coupling. We show that asymmetric optical pumping of a symmetric
resonator enables a dramatic chiral cooling of clockwise and counterclockwise
phonons, while simultaneously suppressing the hidden action of disorder.
Surprisingly, this passive mechanism is also accompanied by a chiral reduction
in heat load leading to optical cooling of the mechanics without added damping,
an effect that has no optical analogue. This technique can potentially improve
upon the fundamental thermal limits of resonant mechanical sensors, which
cannot be attained through sideband cooling.


title: YouTube-8M: A Large-Scale Video Classification Benchmark

abstract:
  Many recent advancements in Computer Vision are attributed to large datasets.
Open-source software packages for Machine Learning and inexpensive commodity
hardware have reduced the barrier of entry for exploring novel approaches at
scale. It is possible to train models over millions of examples within a few
days. Although large-scale datasets exist for image understanding, such as
ImageNet, there are no comparable size video classification datasets.
  In this paper, we introduce YouTube-8M, the largest multi-label video
classification dataset, composed of ~8 million videos (500K hours of video),
annotated with a vocabulary of 4800 visual entities. To get the videos and
their labels, we used a YouTube video annotation system, which labels videos
with their main topics. While the labels are machine-generated, they have
high-precision and are derived from a variety of human-based signals including
metadata and query click signals. We filtered the video labels (Knowledge Graph
entities) using both automated and manual curation strategies, including asking
human raters if the labels are visually recognizable. Then, we decoded each
video at one-frame-per-second, and used a Deep CNN pre-trained on ImageNet to
extract the hidden representation immediately prior to the classification
layer. Finally, we compressed the frame features and make both the features and
video-level labels available for download.
  We trained various (modest) classification models on the dataset, evaluated
them using popular evaluation metrics, and report them as baselines. Despite
the size of the dataset, some of our models train to convergence in less than a
day on a single machine using TensorFlow. We plan to release code for training
a TensorFlow model and for computing metrics.


title: Free space quantum communication with a portable quantum memory

abstract:
  The realization of an elementary quantum network that is intrinsically secure
and operates over long distances requires the interconnection of several
quantum modules performing different tasks. In this work we report the
interconnection of four different quantum modules: (i) a random polarization
qubit generator, (ii) a free-space quantum communication channel, (iii) an
ultra-low noise portable quantum memory and (iv) a qubit decoder, in a
functional elementary quantum network possessing all capabilities needed for
quantum information distribution protocols. We create weak coherent pulses at
the single photon level encoding polarization states $|H\rangle, |V\rangle,
|D\rangle, |A\rangle$ in a randomized sequence. The random qubits are sent over
a free-space link and coupled into a dual rail room temperature quantum memory
and after storage and retrieval are analyzed in a four detector polarization
analysis akin to the requirements of the BB84 protocol. We also show ultra-low
noise and fully-portable operation, paving the way towards memory assisted
all-environment free space quantum cryptographic networks.


title: A Fast Factorization-based Approach to Robust PCA

abstract:
  Robust principal component analysis (RPCA) has been widely used for
recovering low-rank matrices in many data mining and machine learning problems.
It separates a data matrix into a low-rank part and a sparse part. The convex
approach has been well studied in the literature. However, state-of-the-art
algorithms for the convex approach usually have relatively high complexity due
to the need of solving (partial) singular value decompositions of large
matrices. A non-convex approach, AltProj, has also been proposed with lighter
complexity and better scalability. Given the true rank $r$ of the underlying
low rank matrix, AltProj has a complexity of $O(r^2dn)$, where $d\times n$ is
the size of data matrix. In this paper, we propose a novel factorization-based
model of RPCA, which has a complexity of $O(kdn)$, where $k$ is an upper bound
of the true rank. Our method does not need the precise value of the true rank.
From extensive experiments, we observe that AltProj can work only when $r$ is
precisely known in advance; however, when the needed rank parameter $r$ is
specified to a value different from the true rank, AltProj cannot fully
separate the two parts while our method succeeds. Even when both work, our
method is about 4 times faster than AltProj. Our method can be used as a
light-weight, scalable tool for RPCA in the absence of the precise value of the
true rank.


title: Optical Levitation of Nanodiamonds by Doughnut Beams in Vacuum

abstract:
  Optically levitated nanodiamonds with nitrogen-vacancy centers promise a
high-quality hybrid spin-optomechanical system. However, the trapped
nanodiamond absorbs energy form laser beams and causes thermal damage in
vacuum. We propose to solve the problem by trapping a composite particle (a
nanodiamond core coated with a less absorptive silica shell) at the center of
strongly focused doughnut-shaped laser beams. Systematical study on the
trapping stability, heat absorption, and oscillation frequency concludes that
the azimuthally polarized Gaussian beam and the linearly polarized
Laguerre-Gaussian beam ${\rm LG}_{03}$ are the optimal choices. With our
proposal, particles with strong absorption coefficients can be trapped without
obvious heating and, thus, the spin-optomechanical system based on levitated
nanodiamonds are made possible in high vacuum with the present experimental
techniques.


title:
Nonlocal stabilization by starting control of the normal equation
  generated from Helmholtz system

abstract:
  We consider the semilinear parabolic equation of normal type connected with
the 3D Helmholtz equation with periodic boundary condition. The problem of
stabilization to zero of the solution for normal parabolic equation with
arbitrary initial condition by starting control is studied. This problem is
reduced to establishing three inequalities connected with starting control, one
of which has been proved previously. The proof for the other two is given here.


title: Post-AGB evolution much faster than previously thought

abstract:
  For 32 central stars of PNe we present their parameters interpolated among
the new evolutionary sequences. The derived stellar final masses are confined
between 0.53 and 0.58 $M_\odot$ in good agreement with the peak in the white
dwarf mass distribution. Consequently, the inferred star formation history of
the Galactic bulge is well restricted between 3 and 11 Gyr and is compatible
with other published studies. The new evolutionary tracks proved a very good as
a tool for analysis of late stages of stars life. The result provide a
compelling confirmation of the accelerated post-AGB evolution.


title: Multi-Valued Routing Tracks for FPGAs in 28nm FDSOI Technology

abstract:
  In this paper we present quaternary and ternary routing tracks for FPGAs, and
their implementation in 28nm FDSOI technology. We discuss the transistor level
design of multi-valued repeaters, multiplexers and translators, and specific
features of FDSOI technology which make it possible. Next we compare the
multi-valued routing architectures with equivalent single driver two-valued
routing architectures. We show that for long tracks, it is possible to achieve
upto 3x reduction in dynamic switching energy, upto 2x reduction in routing
wire area and 10% reduction in area dedicated to routing resources. The
multi-valued tracks are slightly more susceptible to process variation. We
present a layout method for multivalued standard cells and determine the layout
overhead.We conclude with various usage scenarios of these tracks.


title:
Separability conditions and limit temperatures for entanglement
  detection in two qubit Heisenberg XYZ models

abstract:
  We examine the entanglement of general mixed states of a two qubit Heisenberg
XYZ chain in the presence of a magnetic field, and its detection by means of
different criteria. Both the exact separability conditions and the weaker
conditions implied by the disorder and the von Neumann entropic criteria are
analyzed. The ensuing limit temperatures for entanglement in thermal states of
different XYZ models are then examined and compared with the limit temperature
of the symmetry-breaking solution in a mean field type approximation. The
latter, though generally lower, can also be higher than the exact limit
temperature for entanglement in certain cases, indicating that
symmetry-breaking does not necessarily entail entanglement. The reentry of
entanglement for increasing temperatures is also discussed.


title:
On the formation of DA white dwarfs with low hydrogen contents:
  Preliminary Results

abstract:
  Systematic photometric and asteroseismological studies in the last decade
support the belief that white dwarfs in the solar neighborhood harbor a broad
range of hydrogen-layer contents. The reasons behind this spread of
hydrogen-layer masses are not understood and usually misunderstood. In this
work we present, and review, the different mechanisms that can (or cannot) lead
to the formation of white dwarfs with a broad range hydrogen contents.


title: Observation of a Discrete Time Crystal

abstract:
  Spontaneous symmetry breaking is a fundamental concept in many areas of
physics, ranging from cosmology and particle physics to condensed matter. A
prime example is the breaking of spatial translation symmetry, which underlies
the formation of crystals and the phase transition from liquid to solid.
Analogous to crystals in space, the breaking of translation symmetry in time
and the emergence of a "time crystal" was recently proposed, but later shown to
be forbidden in thermal equilibrium. However, non-equilibrium Floquet systems
subject to a periodic drive can exhibit persistent time-correlations at an
emergent sub-harmonic frequency. This new phase of matter has been dubbed a
"discrete time crystal" (DTC). Here, we present the first experimental
observation of a discrete time crystal, in an interacting spin chain of trapped
atomic ions. We apply a periodic Hamiltonian to the system under many-body
localization (MBL) conditions, and observe a sub-harmonic temporal response
that is robust to external perturbations. Such a time crystal opens the door
for studying systems with long-range spatial-temporal correlations and novel
phases of matter that emerge under intrinsically non-equilibrium conditions.

categories: quant-ph cond-mat.dis-nn cond-mat.quant-gas cond-mat.stat-mech physics.atom-ph


title: Understanding and Exploiting Object Interaction Landscapes

abstract:
  Interactions play a key role in understanding objects and scenes, for both
virtual and real world agents. We introduce a new general representation for
proximal interactions among physical objects that is agnostic to the type of
objects or interaction involved. The representation is based on tracking
particles on one of the participating objects and then observing them with
sensors appropriately placed in the interaction volume or on the interaction
surfaces. We show how to factorize these interaction descriptors and project
them into a particular participating object so as to obtain a new functional
descriptor for that object, its interaction landscape, capturing its observed
use in a spatio-temporal framework. Interaction landscapes are independent of
the particular interaction and capture subtle dynamic effects in how objects
move and behave when in functional use. Our method relates objects based on
their function, establishes correspondences between shapes based on functional
key points and regions, and retrieves peer and partner objects with respect to
an interaction.


title:
Training a Probabilistic Graphical Model with Resistive Switching
  Electronic Synapses

abstract:
  Current large scale implementations of deep learning and data mining require
thousands of processors, massive amounts of off-chip memory, and consume
gigajoules of energy. Emerging memory technologies such as nanoscale
two-terminal resistive switching memory devices offer a compact, scalable and
low power alternative that permits on-chip co-located processing and memory in
fine-grain distributed parallel architecture. Here we report first use of
resistive switching memory devices for implementing and training a Restricted
Boltzmann Machine (RBM), a generative probabilistic graphical model as a key
component for unsupervised learning in deep networks. We experimentally
demonstrate a 45-synapse RBM realized with 90 resistive switching phase change
memory (PCM) elements trained with a bio-inspired variant of the Contrastive
Divergence (CD) algorithm, implementing Hebbian and anti-Hebbian weight
updates. The resistive PCM devices show a two-fold to ten-fold reduction in
error rate in a missing pixel pattern completion task trained over 30 epochs,
compared to untrained case. Measured programming energy consumption is 6.1 nJ
per epoch with the resistive switching PCM devices, a factor of ~150 times
lower than conventional processor-memory systems. We analyze and discuss the
dependence of learning performance on cycle-to-cycle variations as well as
number of gradual levels in the PCM analog memory devices.


title: Permutations, power operations, and the center of the category of racks

abstract:
  Racks and quandles are rich algebraic structures that are strong enough to
classify knots. Here we develop several fundamental categorical aspects of the
theories of racks and quandles and their relation to the theory of
permutations. In particular, we compute the centers of the categories and
describe power operations on them, thereby revealing free extra structure that
is not apparent from the definitions. This also leads to precise
characterizations of these theories in the form of universal properties.


title: The length of an s-increasing sequence of r-tuples

abstract:
  We prove a number of results related to a problem of Po-Shen Loh, which is
equivalent to a problem in Ramsey theory. Let $a=(a_1,a_2,a_3)$ and
$b=(b_1,b_2,b_3)$ be two triples of integers. Define $a$ to be 2-less than $b$
if $a_i<b_i$ for at least two values of $i$, and define a sequence
$a^1,\dots,a^m$ of triples to be 2-increasing if $a^r$ is 2-less than $a^s$
whenever $r<s$. Loh asks how long a 2-increasing sequence can be if all the
triples take values in $\{1,2,\dots,n\}$, and gives a $\log_*$ improvement over
the trivial upper bound of $n^2$ by using the triangle removal lemma. In the
other direction, a simple construction gives a lower bound of $n^{3/2}$. We
look at this problem and a collection of generalizations, improving some of the
known bounds, pointing out connections to other well known problems in extremal
combinatorics, and asking a number of further questions.


title:
Status and performance of the Gemini Planet Imager adaptive optics
  system

abstract:
  The Gemini Planet Imager is a high-contrast near-infrared instrument
specifically designed to image exoplanets and circumstellar disks over a narrow
field of view. We use science data and AO telemetry taken during the first 1.5
yr of the GPI Exoplanet Survey to quantify the performance of the AO system. In
a typical 60 sec H-band exposure, GPI achieves a 5$\sigma$ raw contrast of
10$^{-4}$ at 0.4"; typical final 5$\sigma$ contrasts for full 1 hr sequences
are more than 10 times better than raw contrasts. We find that contrast is
limited by bandwidth wavefront error over much of the PSF. Preliminary
exploratory factor analysis can explain 60-70% of the variance in raw contrasts
with combinations of seeing and wavefront error metrics. We also examine the
effect of higher loop gains on contrast by comparing wavefront error maps
reconstructed from AO telemetry to concurrent IFS images. These results point
to several ways that GPI performance could be improved in software or hardware.


title:
Large collaboration in observational astronomy: the Gemini Planet Imager
  exoplanet survey case

abstract:
  The Gemini Planet Imager (GPI) is a next-generation high-contrast imager
built for the Gemini Observatory. The GPI exoplanet survey (GPIES) consortium
is made up of 102 researchers from 28 institutions in North and South America
and Europe. In November 2014, we launched a search for young Jovian planets and
debris disks. In this paper, we discuss how we have coordinated the work done
by this large team to improve the technical and scientific productivity of the
campaign, and describe lessons we have learned that could be useful for future
instrumentation-based astronomical surveys. The success of GPIES lies mostly on
its decentralized structure, clear definition of policies that are signed by
each member, and the heavy use of modern tools for communicating, exchanging
information, and processing data.


title:
Gemini Planet Imager Observational Calibrations XIV: Polarimetric
  Contrasts and New Data Reduction Techniques

abstract:
  The Gemini Planet Imager (GPI) has been designed for the direct detection and
characterization of exoplanets and circumstellar disks. GPI is equipped with a
dual channel polarimetry mode designed to take advantage of the inherently
polarized light scattered off circumstellar material to further suppress the
residual seeing halo left uncorrected by the adaptive optics. We explore how
recent advances in data reduction techniques reduce systematics and improve the
achievable contrast in polarimetry mode. In particular, we consider different
flux extraction techniques when constructing datacubes from raw data, division
by a polarized flat-field and a method for subtracting instrumental
polarization. Using observations of unpolarized standard stars we find that
GPI's instrumental polarization is consistent with being wavelength independent
within our errors. In addition, we provide polarimetry contrast curves that
demonstrate typical performance throughout the GPIES campaign.


title:
Planet detection down to a few $\lambda$/D: an RSDI/TLOCI approach to
  PSF subtraction

abstract:
  Most current high contrast imaging point spread function (PSF) subtraction
algorithms use some form of a least-squares noise minimization to find
exoplanets that are, before post-processing, often hidden below the
instrumental speckle noise. In the current standard PSF subtraction algorithms,
a set of reference images is derived from the target image sequence to subtract
each target image, using Angular and/or Simultaneous Spectral Differential
Imaging (ADI, SSDI, respectively). However, to avoid excessive exoplanet
self-subtraction, ADI and SSDI (in the absence of a strong spectral feature)
severely limit the available number of reference images at small separations.
This limits the performance of the least-squares algorithm, resulting in lower
sensitivity to exoplanets at small angular separations. Possible solutions are
to use additional reference images by acquiring longer sequences, use SSDI if
the exoplanet is expected to show strong spectral features, or use images
acquired on other targets. The latter option, known as Reference Star
Differential Imaging (RSDI), which relies on the use of reference images that
are highly correlated to the target image, has been ineffective in previous
ground-based high contrast imaging surveys. We present the results of work to
optimize PSF subtraction with the GPIES reference library using a least-squares
algorithm designed to minimize speckle noise and maximize planet throughput,
thus maximizing the planet signal to noise ratio (SNR). Using December 2014 51
Eri GPI data in the inner 100 mas to 300 mas annulus, we find no apparent
improvement in SNR when using RSDI and/or our optimization scheme. This result,
while still being investigated, seems to show that current algorithms on
ADI+SSDI data sets are optimized, and that limited gains can be achieved by
using a PSF archive.


title:
Gemini Planet Imager Observational Calibration XIII: Wavelength
  Calibration Improvements, Stability, and Nonlinearity

abstract:
  We present improvements to the wavelength calibration for the lenslet-based
Integral Field Spectrograph (IFS), that serves as the science instrument for
the Gemini Planet Imager (GPI). The GPI IFS features a 2.7" $\times$ 2.7" field
of view and a 190 $\times$ 190 lenslet array (14.1 mas/lenslet) with spectral
resolving power ranging from R $\sim$ 35 to 78. A unique wavelength solution is
determined for each lenslet characterized by a two-dimensional position, an
n-dimensional polynomial describing the spectral dispersion, and the rotation
of the spectrum with respect to the detector axis. We investigate the
non-linearity of the spectral dispersion across all Y, J, H, and K bands
through both on-sky arc lamp images and simulated IFS images using a model of
the optical path. Additionally, the 10-hole non-redundant masking mode on GPI
provides an alternative measure of wavelength dispersion within a datacube by
cross-correlating reference PSFs with science images. This approach can be used
to confirm deviations from linear dispersion in the reduced datacubes. We find
that the inclusion of a quadratic term provides a factor of 10 improvement in
wavelength solution accuracy over the linear solution and is necessary to
achieve uncertainties of a few hundredths of a pixel in J band to a few
thousands of a pixel in the K bands. This corresponds to a wavelength
uncertainty of $\sim$0.2 nm across all filters.


title:
Supersymmetric solutions of SU(2)-Fayet-Iliopoulos-gauged N=2,d=4
  supergravity

abstract:
  We explore the construction of supersymmetric solutions of theories of
N=2,d=4 supergravity with a SU(2) gauging and SU(2) Fayet-Iliopoulos terms. In
these theories an SU(2) isometry subgroup of the Special Kahler manifold is
gauged together with a SU(2) R-symmetry subgroup. We construct several
solutions of the CP3 quadratic model directly in four dimensions and of the
ST[2,6] model by dimensional reduction of the solutions found by Cariglia and
Mac Conamhna in N=(1,0),d=6 supergravity with the same kind of gauging. In the
CP3 model, we construct an AdS2xS2 solution which is only 1/8 BPS and an RxH3
solution that also preserves 1 of the 8 possible supersymmetries. We show how
to use dimensional reduction as in the ungauged case to obtain RnxSm and also
AdSnxSm-type solutions (with different radii) in - and 4 dimensions from the
6-dimensional AdS3xS3 solution.


title: One-body information loss in fermion systems

abstract:
  We propose an entropic measure of non-classical correlations in general mixed
states of fermion systems, based on the loss of information due to the unread
measurement of the occupancy of single particle states of a given basis. When
minimized over all possible single particle bases, the measure reduces to an
entanglement entropy for pure states and vanishes only for states which are
diagonal in a Slater determinant basis. The approach is also suitable for
states having definite number parity yet not necessarily a fixed particle
number, in which case the minimization can be extended to all bases related
through a Bogoliubov transformation if quasiparticle mode measurements are also
considered. General stationary conditions for determining the optimizing basis
are derived. For a mixture of a general pure state with the maximally mixed
state, a general analytic evaluation of the present measure and optimizing
basis is provided, which shows that non-entangled mixed states may nonetheless
exhibit a non-zero information loss.


title:
Vertex stability and topological transitions in vertex models of foams
  and epithelia

abstract:
  In computer simulations of dry foams and of epithelial tissues, vertex models
are often used to describe the shape and motion of individual cells. Although
these models have been widely adopted, relatively little is known about their
basic theoretical properties. For example, while fourfold vertices in real
foams are always unstable, it remains unclear whether a simplified vertex model
description has the same behavior. Here, we study vertex stability and the
dynamics of T1 topological transitions in vertex models. We show that, when all
edges have the same tension, stationary fourfold vertices in these models do
indeed always break up. In contrast, when tensions are allowed to depend on
edge orientation, fourfold vertices can become stable, as is observed in some
biological systems. More generally, our formulation of vertex stability leads
to an improved treatment of T1 transitions in simulations and paves the way for
studies of more biologically realistic models that couple topological
transitions to the dynamics of regulatory proteins.


title:
A Comprehensive Methodology for Volt-VAR Optimization in Active Smart
  Grids

abstract:
  This paper considers the problem of Volt-VAR Optimization (VVO) in active
smart grids. Active smart grids are equipped with distributed generators,
distributed storage systems, and tie-line switches that allow for topological
reconfiguration. In this paper, the joint operation of the remotely
controllable switches, storage units, under load tap changers, and shunt
capacitors is formulated for a day-ahead operation scheme. The proposed VVO
problem aims at minimizing the expected active power loss in the system and is
formulated as a mixed-integer quadratic program. The stochasticity of the wind
power generation is addressed through a first-order Markov chain model.
Numerical results on a 33-node, 12.66 kV active smart grid using real data from
smart meters and wind turbines are presented and compared for various test
cases.


title: Dependence of fusion on isospin dynamics

abstract:
  We introduce a new microscopic approach to calculate the dependence of fusion
barriers and cross-sections on isospin dynamics. The method is based on the
time-dependent Hartree-Fock theory and the isoscalar and isovector properties
of the energy density functional (EDF). The contribution to the fusion barriers
originating from the isoscalar and isovector parts of the EDF is calculated. It
is shown that for non-symmetric systems the isovector dynamics influence the
sub-barrier fusion cross-sections. For most systems this results in an
enhancement of the sub-barrier cross-sections, while for others we observe
differing degrees of hindrance. We use this approach to provide an explanation
of recently measured fusion cross sections which show a surprising enhancement
at low $E_\mathrm{c.m.}$ energies for the system $^{40}$Ca+$^{132}$Sn as
compared to the more neutron-rich system $^{48}$Ca+$^{132}$Sn, and discuss the
dependence of sub-barrier fusion cross-sections on transfer.


title: Breaking the Loss Limitation of On-chip High-confinement Resonators

abstract:
  On-chip optical resonators have the promise of revolutionizing numerous
fields including metrology and sensing; however, their optical losses have
always lagged behind their larger discrete resonator counterparts based on
crystalline materials and flowable glass. Silicon nitride (Si3N4) ring
resonators open up capabilities for optical routing, frequency comb generation,
optical clocks and high precision sensing on an integrated platform. However,
simultaneously achieving high quality factor and high confinement in Si3N4
(critical for nonlinear processes for example) remains a challenge. Here, we
show that addressing surface roughness enables us to overcome the loss
limitations and achieve high-confinement, on-chip ring resonators with a
quality factor (Q) of 37 million for a ring with 2.5 {\mu}m width and 67
million for a ring with 10 {\mu}m width. We show a clear systematic path for
achieving these high quality factors. Furthermore, we extract the loss limited
by the material absorption in our films to be 0.13 dB/m, which corresponds to
an absorption limited Q of at least 170 million by comparing two resonators
with different degrees of confinement. Our work provides a chip-scale platform
for applications such as ultra-low power frequency comb generation, high
precision sensing, laser stabilization and sideband resolved optomechanics.


title:
The inner mass distribution of late-type spiral galaxies from SAURON
  stellar kinematic maps

abstract:
  We infer the central mass distributions within 0.4-1.2 disc scale lengths of
18 late-type spiral galaxies using two different dynamical modelling approaches
- the Asymmetric Drift Correction (ADC) and axisymmetric Jeans Anisotropic
Multi-gaussian expansion (JAM) model. ADC adopts a thin disc assumption,
whereas JAM does a full line-of-sight velocity integration. We use stellar
kinematics maps obtained with the integral-field spectrograph SAURON to derive
the corresponding circular velocity curves from the two models. To find their
best-fit values, we apply Markov Chain Monte Carlo (MCMC) method. ADC and JAM
modelling approaches are consistent within 5% uncertainty when the ordered
motions are significant comparable to the random motions, i.e,
$\overline{v_{\phi}}/\sigma_R$ is locally greater than 1.5. Below this value,
the ratio $v_\mathrm{c,JAM}/v_\mathrm{c,ADC}$ gradually increases with
decreasing $\overline{v_{\phi}}/\sigma_R$, reaching $v_\mathrm{c,JAM}\approx 2
\times v_\mathrm{c,ADC}$. Such conditions indicate that the stellar masses of
the galaxies in our sample are not confined to their disk planes and likely
have a non-negligible contribution from their bulges and thick disks.


title: Sparse Bounds for Random Discrete Carleson Theorems

abstract:
  We study discrete random variants of the Carleson maximal operator.
Intriguingly, these questions remain subtle and difficult, even in this
setting. Let $\{X_m\}$ be an independent sequence of $\{0,1\}$ random variables
with expectations \[ \mathbb E X_m = \sigma_m = m^{-\alpha}, \ 0 < \alpha <
1/2, \] and $ S_m = \sum_{k=1} ^{m} X_k$. Then the maximal operator below
almost surely is bounded from $ \ell ^{p}$ to $ \ell ^{p}$, provided the
Minkowski dimension of $ \Lambda \subset [-1/2, 1/2]$ is strictly less than $
1- \alpha $. \[ \sup_{\lambda \in \Lambda } \Bigl| \sum_{m\neq 0} X_{\lvert
m\rvert } \frac{e( \lambda m )}{ {\rm sgn} (m)S_{ |m| }} f(x- m) \Bigr|. \]
This operator also satisfies a sparse type bound. The form of the sparse bound
immediately implies weighted estimates in all $ \ell ^{2}$, which are novel in
this setting. Variants and extensions are also considered.


title: Some complexity results in the theory of normal numbers

abstract:
  Let $\mathscr{N}(b)$ be the set of real numbers which are normal to base $b$.
A well-known result of H. Ki and T. Linton is that $\mathscr{N}(b)$ is
$\boldsymbol{\Pi}^0_3$-complete. We show that the set $\mathscr{N}(b)$ of reals
which preserve $\mathscr{N}(b)$ under addition is also
$\boldsymbol{\Pi}^0_3$-complete. We use the characteriztion of $\mathscr{N}(b)$
given by G. Rauzy in terms of an entropy-like quantity called the noise. It
follows from our results that no further characteriztion theorems could result
in a still better bound on the complexity of $\mathscr{N}(b)$. We compute the
exact descriptive complexity of other naturally occurring sets associated with
noise. One of these is complete at the $\boldsymbol{\Pi}^0_4$ level. Finally,
we get upper and lower bounds on the Hausdorff dimension of the level sets
associated with the noise.


title:
Optimizing Neural Network Hyperparameters with Gaussian Processes for
  Dialog Act Classification

abstract:
  Systems based on artificial neural networks (ANNs) have achieved
state-of-the-art results in many natural language processing tasks. Although
ANNs do not require manually engineered features, ANNs have many
hyperparameters to be optimized. The choice of hyperparameters significantly
impacts models' performances. However, the ANN hyperparameters are typically
chosen by manual, grid, or random search, which either requires expert
experiences or is computationally expensive. Recent approaches based on
Bayesian optimization using Gaussian processes (GPs) is a more systematic way
to automatically pinpoint optimal or near-optimal machine learning
hyperparameters. Using a previously published ANN model yielding
state-of-the-art results for dialog act classification, we demonstrate that
optimizing hyperparameters using GP further improves the results, and reduces
the computational time by a factor of 4 compared to a random search. Therefore
it is a useful technique for tuning ANN models to yield the best performances
for natural language processing tasks.


title:
Photoconductivity of few-layered p-WSe2 phototransistors via
  multi-terminal measurements

abstract:
  Recently, two-dimensional materials and in particular transition metal
dichalcogenides (TMDs) were extensively studied because of their strong
light-matter interaction and the remarkable optoelectronic response of their
field-effect transistors (FETs). Here, we report a photoconductivity study from
FETs built from few-layers of p-WSe2 measured in a multi-terminal configuration
under illumination by a 532 nm laser source. The photogenerated current was
measured as a function of the incident optical power, of the drain-to-source
bias and of the gate voltage. We observe a considerably larger
photoconductivity when the phototransistors were measured via a four-terminal
configuration when compared to a two-terminal one. For an incident laser power
of 248 nW, we extract 18 A/W and ~4000% for the two-terminal responsivity (R)
and the concomitant external quantum efficiency (EQE) respectively, when a bias
voltage Vds = 1 V and a gate voltage Vbg = 10 V are applied to the sample. R
and EQE are observed to increase by 370% to ~85 A/W and ~20000% respectively,
when using a four-terminal configuration. Thus, we conclude that previous
reports have severely underestimated the optoelectronic response of transition
metal dichalcogenides, which in fact reveals a remarkable potential for
photosensing applications.


title:
Improved Measurement of the Spectral Index of the Diffuse Radio
  Background Between 90 and 190 MHz

abstract:
  We report absolutely calibrated measurements of diffuse radio emission
between 90 and 190 MHz from the Experiment to Detect the Global EoR Signature
(EDGES). EDGES employs a wide beam zenith-pointing dipole antenna centred on a
declination of -26.7$^\circ$. We measure the sky brightness temperature as a
function of frequency averaged over the EDGES beam from 211 nights of data
acquired from July 2015 to March 2016. We derive the spectral index, $\beta$,
as a function of local sidereal time (LST) and find -2.60 > $\beta$ > -2.62
$\pm$0.02 between 0 and 12 h LST. When the Galactic Centre is in the sky, the
spectral index flattens, reaching $\beta$ = -2.50 $\pm$0.02 at 17.7 h. The
EDGES instrument is shown to be very stable throughout the observations with
night-to-night reproducibility of $\sigma_{\beta}$ < 0.003. Including
systematic uncertainty, the overall uncertainty of $\beta$ is 0.02 across all
LST bins. These results improve on the earlier findings of Rogers & Bowman
(2008) by reducing the spectral index uncertainty from 0.10 to 0.02 while
considering more extensive sources of errors. We compare our measurements with
spectral index simulations derived from the Global Sky Model (GSM) of de
Oliveira-Costa et al. (2008) and with fits between the Guzm\'an et al. (2011)
45 MHz and Haslam et al. (1982) 408 MHz maps. We find good agreement at the
transit of the Galactic Centre. Away from transit, the GSM tends to
over-predict (GSM less negative) by 0.05 < $\Delta_{\beta} =
\beta_{\text{GSM}}-\beta_{\text{EDGES}}$ < 0.12, while the 45-408 MHz fits tend
to over-predict by $\Delta_{\beta}$ < 0.05.


title: On (Non)Supermodularity of Average Control Energy

abstract:
  Given a linear system, we consider the expected energy to move from the
origin to a uniformly random point on the unit sphere as a function of the set
of actuated variables. We show this function is not necessarily supermodular,
correcting some claims in the existing literature.