title: The G2+G2t complex as a fast and massive outflow?

abstract:
  Observations of the gas component of the cloud G2 in the Galactic Center have
revealed its connection to a tail (G2t) lying on the same orbit. More recent
studies indicate a connection between G2 and G1, another cloud detected on the
blueshifted side of G2's orbit, suggesting a scenario in which G2 is a denser
clump in a stream of gas. In this Letter we show that a simulation of an
outflow by a central source (possibly a T Tauri star) moving on G2's orbit and
interacting with a hot atmosphere surrounding SgrA* can have G2 and G2t as a
byproduct. G2 would be the bow-shock formed in the head of the source, while
G2t might be the result of the stripping of the rest of the shocked material by
the ram pressure of the surrounding hot gas and of its successive accumulation
in the trailing region. Mock position-velocity diagrams for the Br$\gamma$
emission for this simulation can indeed reproduce the correct position and
velocity of G2t, as well as the more tenuous material in between. Though some
tension between the observations and the simulated model remains, we argue that
this might be due to issues in the construction of observed position-velocity
(PV) diagrams and/or to a poor treatment of some physical processes - like
hydrodynamic mixing - in our simulation.


title: Disentangling the ICL with the CHEFs: Abell 2744 as a case study

abstract:
  Measurements of the intracluster light (ICL) are still prone to
methodological ambiguities and there are multiple techniques in the literature
for that purpose, mostly based on the binding energy, the local density
distribution, or the surface brightness. A common issue with these methods is
the a priori assumption of a number of hypotheses on either the ICL morphology,
its surface brightness level or some properties of the brightest cluster galaxy
(BCG). The discrepancy on the results is high, and numerical simulations just
bound the ICL fraction in present-day galaxy clusters to the range 10-50%. We
developed a new algorithm based on the Chebyshev-Fourier functions (CHEFs) to
estimate the ICL fraction without relying on any a priori assumption on the
physical or geometrical characteristics of the ICL. We are able to not only
disentangle the ICL from the galatic luminosity but mark out the limits of the
BCG from the ICL in a natural way. We test our tecnique with the recently
released data of the cluster Abell 2744, observed by the Frontier Fields
program. The complexity of this multiple merging cluster system and the
formidable depth of these images make it a challenging test case to prove the
efficiency of our algorithm. We found a final ICL fraction of 19.17+-2.87%,
which is very consistent with numerical simulations.


title:
Extending the scope of holographic mutual information and chaotic
  behavior

abstract:
  We extend the use of holography to investigate the scrambling properties of
various physical systems. Specifically, we consider: (i) non-conformal
backgrounds of black $Dp$ branes, (ii) asymptotically Lifshitz black holes, and
(iii) black $AdS$ solutions of Gauss-Bonnet gravity. We use the disruption of
the entanglement entropy as a probe of the chaotic features of such systems.
Our analysis shows that these theories share the same type of behavior as
conformal theories as they undergo chaos; however, in the case of Gauss-Bonnet
gravity, we find a stark difference in the evolution of the mutual information
for negative Gauss-Bonnet coupling. This may signal an inconsistency of the
latter.


title:
Deep spectroscopy of nearby galaxy clusters: I. Spectroscopic luminosity
  function of Abell 85

abstract:
  We present a new deep spectroscopic catalogue for Abell 85, within 3.0
$\times$ 2.6 Mpc$^2$ and down to $M_{r} \sim M_{r}^* +6$. Using the Visible
Multi-Object Spectrograph at the Very Large Telescope (VIMOS@VLT) and the
AutoFiber 2 at the William Herschel Telescope (AF2@WHT), we obtained almost
1,430 new redshifts for galaxies with $m_r \leq 21$ mag and $\langle \mu_{e,r}
\rangle \leq 24$ mag arcsec$^{-2}$. These redshifts, together with SDSS-DR6 and
NED spectroscopic information, result in 460 confirmed cluster members. This
dataset allows the study of the luminosity function (LF) of the cluster
galaxies covering three orders of magnitudes in luminosities. The total and
radial LFs are best modelled by a double Schechter function. The normalized LFs
show that their bright ($M_{r} \leq -21.5$) and faint ($M_{r}\geq -18.0$) ends
are independent of clustercentric distance and similar to the field LFs unlike
the intermediate luminosity range ($-21.5 \leq M_{r} \leq -18.0$). Similar
results are found for the LFs of the dominant types of galaxies: red, passive,
virialized and early-infall members. On the contrary, the LFs of blue, star
forming, non-virialized and recent-infall galaxies are well described by a
single Schechter function. These populations contribute to a small fraction of
the galaxy density in the innermost cluster region. However, in the outskirts
of the cluster, they have similar densities to red, passive, virialized and
early-infall members at the LF faint end. These results confirm a clear
dependence of the colour and star formation of Abell 85 members in the cluster
centric distance.


title: Is the gravitational-wave ringdown a probe of the event horizon?

abstract:
  It is commonly believed that the ringdown signal from a binary coalescence
provides a conclusive proof for the formation of an event horizon after the
merger. This expectation is based on the assumption that the ringdown waveform
at intermediate times is dominated by the quasinormal modes of the final
object. We point out that this assumption should be taken with great care, and
that very compact objects with a light ring will display a similar ringdown
stage, even when their quasinormal-mode spectrum is completely different from
that of a black hole. In other words, universal ringdown waveforms indicate the
presence of light rings, rather than of horizons. Only precision observations
of the late-time ringdown signal, where the differences in the quasinormal-mode
spectrum eventually show up, can be used to rule out exotic alternatives to
black holes and to test quantum effects at the horizon scale.


title: f(Lovelock) theories of gravity

abstract:
  f(Lovelock) gravities are simple generalizations of the usual f(R) and
Lovelock theories in which the gravitational action depends on some arbitrary
function of the corresponding dimensionally-extended Euler densities. In this
paper we study several aspects of these theories in general dimensions. We
start by identifying the generalized boundary term which makes the
gravitational variational problem well-posed. Then, we show that these theories
are equivalent to certain scalar-tensor theories and how this relation is
characterized by the Hessian of f. We also study the linearized equations of
the theory on general maximally symmetric backgrounds. Remarkably, we find that
these theories do not propagate the usual ghost-like massive gravitons
characteristic of higher-derivative gravities on such backgrounds. In some
non-trivial cases, the additional scalar associated to the trace of the metric
perturbation is also absent, being the usual graviton the only dynamical field.
In those cases, the linearized equations are exactly the same as in Einstein
gravity up to an overall factor, making them appealing as holographic toy
models. We also find constraints on the couplings of a broad family of
five-dimensional f(Lovelock) theories using holographic entanglement entropy.
Finally, we construct new analytic asymptotically flat and AdS/dS black hole
solutions for some classes of f(Lovelock) gravities in various dimensions.


title:
Selective activation of resting state networks following focal
  stimulation in a connectome- based network model of the human brain

abstract:
  Imaging studies suggest that the functional connectivity patterns of resting
state networks (RS-networks) reflect underlying structural connectivity (SC).
If the connectome constrains how brain areas are functionally connected, the
stimulation of specific brain areas should produce a characteristic wave of
activity ultimately resolving into RS-networks. To systematically test this
hypothesis, we use a connectome-based network model of the human brain with
detailed realistic SC. We systematically activate all possible thalamic and
cortical areas with focal stimulation patterns and confirm that the stimulation
of specific areas evokes network patterns that closely resemble RS-networks.
For some sites, one or no RS-network is engaged, whereas for other sites more
than one RS-network may evolve. Our results confirm that the brain is operating
at the edge of criticality, wherein stimulation produces a cascade of
functional network recruitments, collapsing onto a smaller subspace that is
constrained in part by the anatomical local and long-range SCs. We suggest that
information flow, and subsequent cognitive processing, follows specific routes
imposed by connectome features, and that these routes explain the emergence of
RS-networks. Since brain stimulation can be used to diagnose/treat neurological
disorders, we provide a look-up table showing which areas need to be stimulated
to activate specific RS-networks.


title: Control Systems on Flag Manifolds and their chain Control sets

abstract:
  In this paper we shown that the chain control sets of induced systems on flag
manifolds coincides with their analogous one defined via semigroup actions.
Consequently, any chain control set of the system contains a control set with
nonempty interior and, if the number of the control sets with nonempty interior
coincides with the number of the chain control sets, then the closure of any
control set with nonempty interior is a chain control set.


title:
Yet another look at positive linear operators, $q$-monotonicity and
  applications

abstract:
  For each $q\in{\mathbb{N}}_0$, we construct positive linear polynomial
approximation operators $M_n$ that simultaneously preserve $k$-monotonicity for
all $0\leq k\leq q$ and yield the estimate \[ |f(x)-M_n(f, x)| \leq c
\omega_2^{\varphi^\lambda} \left(f, n^{-1} \varphi^{1-\lambda/2}(x)
\left(\varphi(x) + 1/n \right)^{-\lambda/2} \right) , \] for $x\in [0,1]$ and
$\lambda\in [0, 2)$, where $\varphi(x) := \sqrt{x(1-x)}$ and $\omega_2^{\psi}$
is the second Ditzian-Totik modulus of smoothness corresponding to the
"step-weight function" $\psi$.
  In particular, this implies that the rate of best uniform $q$-monotone
polynomial approximation can be estimated in terms of $\omega_2^{\varphi}
\left(f, 1/n \right)$.


title:
The Herschel Orion Protostar Survey: Spectral Energy Distributions and
  Fits Using a Grid of Protostellar Models

abstract:
  We present key results from the Herschel Orion Protostar Survey (HOPS):
spectral energy distributions (SEDs) and model fits of 330 young stellar
objects, predominantly protostars, in the Orion molecular clouds. This is the
largest sample of protostars studied in a single, nearby star-formation
complex. With near-infrared photometry from 2MASS, mid- and far-infrared data
from Spitzer and Herschel, and sub-millimeter photometry from APEX, our SEDs
cover 1.2-870 $\mu$m and sample the peak of the protostellar envelope emission
at ~100 $\mu$m. Using mid-IR spectral indices and bolometric temperatures, we
classify our sample into 92 Class 0 protostars, 125 Class I protostars, 102
flat-spectrum sources, and 11 Class II pre-main-sequence stars. We implement a
simple protostellar model (including a disk in an infalling envelope with
outflow cavities) to generate a grid of 30400 model SEDs and use it to
determine the best-fit model parameters for each protostar. We argue that
far-IR data are essential for accurate constraints on protostellar envelope
properties. We find that most protostars, and in particular the flat-spectrum
sources, are well-fit. The median envelope density and median inclination angle
decrease from Class 0 to Class I to flat-spectrum protostars, despite the broad
range in best-fit parameters in each of the three categories. We also discuss
degeneracies in our model parameters. Our results confirm that the different
protostellar classes generally correspond to an evolutionary sequence with a
decreasing envelope infall rate, but the inclination angle also plays a role in
the appearance, and thus interpretation, of the SEDs.


title: Perspectives for Spintronics in 2D Materials

abstract:
  The past decade has been especially creative for spintronics since the
(re)discovery of various two dimensional (2D) materials. Due to the unusual
physical characteristics, 2D materials have provided new platforms to probe the
spin interaction with other degrees of freedom for electrons, as well as to be
used for novel spintronics applications. This review briefly presents the most
important recent and ongoing research for spintronics in 2D materials.


title:
ALMA observations of the submillimetre hydrogen recombination line from
  the type 2 active nucleus of NGC 1068

abstract:
  Hydrogen recombination lines at the submillimetre band (submm-RLs) can serve
as probes of ionized gas without dust extinction. One therefore expects to
probe the broad line region (BLR) of an obscured (type 2) active galactic
nucleus (AGN) with those lines. However, admitting the large uncertainty in the
continuum level, here we report on the non-detection of both broad and narrow
H26$\alpha$ emission line (rest frequency = 353.62 GHz) towards the
prototypical type 2 AGN of NGC 1068 with the Atacama Large
Millimeter/submillimeter Array (ALMA). We also investigate the nature of BLR
clouds that can emit submm-RLs with model calculations. As a result, we suggest
that clouds with an electron density ($N_e$) of $\sim$ 10$^9$ cm$^{-3}$ can
mainly contribute to broad submm-RLs in terms of the line flux. On the other
hand, line flux from other density clouds would be insignificant considering
their too large or too small line optical depths. However, even for the case of
$N_e \sim 10^9$ cm$^{-3}$ clouds, we also suggest that the expected line flux
is extremely low, which is impractical to detect even with ALMA.


title:
Relaxation of a classical spin coupled to a strongly correlated electron
  system

abstract:
  A classical spin which is antiferromagnetically coupled to a system of
strongly correlated conduction electrons is shown to exhibit unconventional
real-time dynamics which cannot be described by Gilbert damping. Depending on
the strength of the local Coulomb interaction, the two main electronic
dissipation channels, transport of excitations via correlated hopping and via
excitations of correlation-induced magnetic moments, become active on largely
different time scales. We demonstrate that this can lead to a prethermalization
scenario which so far has been observed in purely electronic systems only and
which is governed here by proximity to the divergent magnetic time scale in the
infinite-U limit.


title:
On the Launching and Structure of Radiatively Driven Winds in Wolf-Rayet
  Stars

abstract:
  Hydrostatic models of Wolf-Rayet stars typically contain low-density outer
envelopes that inflate the stellar radii by a factor of several and are capped
by a denser shell of gas. Inflated envelopes and density inversions are
hallmarks of envelopes that become super-Eddington as they cross the iron-group
opacity peak, but these features disappear when mass loss is sufficiently
rapid. We re-examine the structures of steady, spherically symmetric wind
solutions that cross a sonic point at high optical depth, identifying the
physical mechanism by which outflow affects the stellar structure, and provide
an improved analytical estimate for the critical mass loss rate above which
extended structures are erased. Weak-flow solutions below this limit resemble
hydrostatic stars even in supersonic zones; however, we infer that these fail
to successfully launch optically thick winds. Wolf-Rayet envelopes will
therefore likely correspond to the strong, compact solutions. We also find that
wind solutions with negligible gas pressure are stably stratified at and below
the sonic point. This implies that convection is not the source of variability
in Wolf-Rayet stars, as has been suggested; but, acoustic instabilities provide
an alternative explanation. Our solutions are limited to high optical depths by
our neglect of Doppler enhancements to the opacity, and do not account for
acoustic instabilities at high Eddington factors; yet they provide useful
insights into Wolf-Rayet stellar structures.


title: Three paths toward the quantum angle operator

abstract:
  We examine mathematical questions around angle (or phase) operator associated
with a number operator through a short list of basic requirements. We implement
three methods of construction of quantum angle. The first one is based on
operator theory and parallels the definition of angle for the upper half-circle
through its cosine and completed by a sign inversion. The two other methods are
integral quantization generalizing in a certain sense the Berezin-Klauder
approaches. One method pertains to Weyl-Heisenberg integral quantization of the
plane viewed as the phase space of the motion on the line. It depends on a
family of "weight" functions on the plane. The third method rests upon coherent
state quantization of the cylinder viewed as the phase space of the motion on
the circle. The construction of these coherent states depends on a family of
probability distributions on the line.


title: Stuck in a What? Adventures in Weight Space

abstract:
  Deep learning researchers commonly suggest that converged models are stuck in
local minima. More recently, some researchers observed that under reasonable
assumptions, the vast majority of critical points are saddle points, not true
minima. Both descriptions suggest that weights converge around a point in
weight space, be it a local optima or merely a critical point. However, it's
possible that neither interpretation is accurate. As neural networks are
typically over-complete, it's easy to show the existence of vast continuous
regions through weight space with equal loss. In this paper, we build on recent
work empirically characterizing the error surfaces of neural networks. We
analyze training paths through weight space, presenting evidence that apparent
convergence of loss does not correspond to weights arriving at critical points,
but instead to large movements through flat regions of weight space. While it's
trivial to show that neural network error surfaces are globally non-convex, we
show that error surfaces are also locally non-convex, even after breaking
symmetry with a random initialization and also after partial training.


title:
Global well-posedness of the Euler-Korteweg system for small
  irrotational data

abstract:
  The Euler-Korteweg equations are a modification of the Euler equations that
takes into account capillary effects. In the general case they form a
quasi-linear system that can be recast as a degenerate Schr\"odinger type
equation. Local well-posedness (in subcritical Sobolev spaces) was obtained by
Benzoni-Danchin-Descombes in any space dimension, however, except in some
special case (semi-linear with particular pressure) no global well-posedness is
known. We prove here that under a natural stability condition on the pressure,
global well-posedness holds in dimension $d\geq 3$ for small irrotational
initial data. The proof is based on a modified energy estimate, standard
dispersive properties if $d\geq 5$, and a careful study of the nonlinear
structure of the quadratic terms in dimension $3$ and $4$ involving the theory
of space time resonance.


title:
Constraining the redshifted 21-cm signal with the unresolved soft X-ray
  background

abstract:
  We use the observed unresolved cosmic X-ray background (CXRB) in the 0.5-2
keV band and existing upper limits on the 21-cm power spectrum to constrain the
high-redshift population of X-ray sources, focusing on their effect on the
thermal history of the Universe and the cosmic 21-cm signal. Because the
properties of these sources are poorly constrained, we consider hot gas, X-ray
binaries and mini-quasars (i.e., sources with soft or hard X-ray spectra) as
possible candidates. We find that (1) the soft-band CXRB sets an upper limit on
the X-ray efficiency of sources that existed before the end of reionization,
which is one-to-two orders of magnitude higher than typically assumed
efficiencies, (2) hard sources are more effective in generating the CXRB than
the soft ones, (3) the commonly-assumed limit of saturated heating is not valid
during the first half of reionization in the case of hard sources, with any
allowed value of X-ray efficiency, (4) the maximal allowed X-ray efficiency
sets a lower limit on the depth of the absorption trough in the global 21-cm
signal and an upper limit on the height of the emission peak, while in the
21-cm power spectrum it sets a minimum amplitude and frequency for the
high-redshift peaks, and (5) the existing upper limit on the 21-cm power
spectrum sets a lower limit on the X-ray efficiency for each model. When
combined with the 21-cm global signal, the CXRB will be useful for breaking
degeneracies and helping constrain the nature of high-redshift heating sources.


title:
Lecture notes on Gaussian multiplicative chaos and Liouville Quantum
  Gravity

abstract:
  The purpose of these notes, based on a course given by the second author at
Les Houches summer school, is to explain the probabilistic construction of
Polyakov's Liouville quantum gravity using the theory of Gaussian
multiplicative chaos. In particular, these notes contain a detailed description
of the so-called Liouville measures of the theory and their conjectured
relation to the scaling limit of large planar maps properly embedded in the
sphere. These notes are rather short and require no prior knowledge on the
topic.


title: Investigating Drivers' Head and Glance Correspondence

abstract:
  The relationship between a driver's glance pattern and corresponding head
rotation is highly complex due to its nonlinear dependence on the individual,
task, and driving context. This study explores the ability of head pose to
serve as an estimator for driver gaze by connecting head rotation data with
manually coded gaze region data using both a statistical analysis approach and
a predictive (i.e., machine learning) approach. For the latter, classification
accuracy increased as visual angles between two glance locations increased. In
other words, the greater the shift in gaze, the higher the accuracy of
classification. This is an intuitive but important concept that we make
explicit through our analysis. The highest accuracy achieved was 83% using the
method of Hidden Markov Models (HMM) for the binary gaze classification problem
of (1) the forward roadway versus (2) the center stack. Results suggest that
although there are individual differences in head-glance correspondence while
driving, classifier models based on head-rotation data may be robust to these
differences and therefore can serve as reasonable estimators for glance
location. The results suggest that driver head pose can be used as a surrogate
for eye gaze in several key conditions including the identification of
high-eccentricity glances. Inexpensive driver head pose tracking may be a key
element in detection systems developed to mitigate driver distraction and
inattention.


title:
Experimental Investigation of Temperature-Dependent Gilbert Damping in
  Permalloy Thin Films

abstract:
  The Gilbert damping of ferromagnetic materials is arguably the most important
but least understood phenomenological parameter that dictates real-time
magnetization dynamics. Understanding the physical origin of the Gilbert
damping is highly relevant to developing future fast switching spintronics
devices such as magnetic sensors and magnetic random access memory. Here, we
report an experimental study of temperature-dependent Gilbert damping in
permalloy (Py) thin films of varying thicknesses by ferromagnetic resonance.
From the thickness dependence, two independent contributions to the Gilbert
damping are identified, namely bulk damping and surface damping. Of particular
interest, bulk damping decreases monotonically as the temperature decreases,
while surface damping shows an enhancement peak at the temperature of ~50 K.
These results provide an important insight to the physical origin of the
Gilbert damping in ultrathin magnetic films.


title:
Generalized local frame transformation theory for excited species in
  external fields

abstract:
  A rigorous theoretical framework is developed for a generalized local frame
transformation theory (GLFT). The GLFT is applicable to the following systems:
to Rydberg atoms or molecules in an electric field, or to negative ions in any
combination of electric and/or magnetic fields. A first test application to the
photoionization spectra of Rydberg atoms in an external electric field
demonstrates dramatic improvement over the first version of the local frame
transformation theory developed initially by Fano and Harmin. This revised GLFT
theory yields non-trivial corrections because it now includes the full on-shell
Hilbert space without adopting the truncations in the original theory.
Comparisons of the semi-analytical GLFT Stark spectra with {\it ab initio}
numerical simulations yields errors in the range of a few tens of MHz, an
improvement over the original Fano-Harmin theory whose errors are 10-100 times
larger. Our analysis provides a systematic pathway to precisely describe the
corresponding photoabsorption spectra that should be accurate enough to meet
most modern experimental standards.


title: High Temperature Equation of State of Metallic Hydrogen

abstract:
  The equation of state of liquid metallic hydrogen is solved numerically.
Investigations are carried out at temperatures, which correspond both to the
experimental conditions under which metallic hydrogen is produced on earth and
the conditions in the cores of giant planets of the solar system such as
Jupiter and Saturn. It is assumed that hydrogen is in an atomic state and all
its electrons are collectivized. Perturbation theory in the electron and proton
interaction is applied to determine the thermodynamic potentials of metallic
hydrogen. The electron subsystem is considered in the randomphase approximation
with regard to the exchange interaction and the correlation of electrons in the
local field approximation. The interproton interaction is taken into account in
the hard spheres approximation. The thermodynamic characteristics of metallic
hydrogen are calculated with regard to the zero-, second-, and thirdorder
perturbation theory terms. The third-order term proves to be rather essential
at moderately high temperatures and densities, although it is much smaller than
the second-order term. The thermodynamic potentials of metallic hydrogen are
monotonically increasing functions of density and temperature. The values of
pressure for the temperatures and pressures that are characteristic of the
conditions under which metallic hydrogen is produced on earth coincide with the
corresponding values reported by the discoverers of metallic hydrogen to a high
degree of accuracy. The temperature and density ranges are found in which there
exists a liquid phase of metallic hydrogen.


title:
Frobenius pairs in abelian categories: correspondences with cotorsion
  pairs, exact model categories, and Auslander-Buchweitz contexts

abstract:
  In this work, we revisit Auslander-Buchweitz Approximation Theory and find
some relations with cotorsion pairs and model category structures. From the
notions of relatives generators and cogenerators in Approximation Theory, we
introduce the concept of left Frobenius pairs $(\mathcal{X},\omega)$ in an
abelian category $\mathcal{C}$. We show how to construct from
$(\mathcal{X},\omega)$ a projective exact model structure on
$\mathcal{X}^\wedge$, as a result of Hovey-Gillespie Correspondence applied to
two compatible and complete cotorsion pairs in $\mathcal{X}^\wedge$. These
pairs can be regarded as examples of what we call cotorsion pairs relative to a
thick subcategory of $\mathcal{C}$. We establish some correspondences between
Frobenius pairs, relative cotorsion pairs, exact model structures and
Auslander-Buchweitz contexts. Finally, some applications of these results are
given in the context of Gorenstein homological algebra by generalizing some
existing model structures on the categories of modules over Gorenstein and
Ding-Chen rings, and by encoding the stable module category of a ring as a
certain homotopy category. We also present some connections with perfect
cotorsion pairs, covering classes, and cotilting modules.


title:
Ferromagnetism and superconductivity with possible $p+ip$ pairing
  symmetry in partially hydrogenated graphene

abstract:
  By means of first-principles calculations, we predict two new types of
partially hydrogenated graphene systems: C$_{6}$H$_{1}$ and C$_{6}$H$_{5}$,
which are shown to be ferromagnetic (FM) semimetal and FM narrow-gap
semiconductor, respectively. When properly doped, the Fermi surface of the two
systems consists of an electron pocket or six hole patches in the first
Brillouin zone with completely spin-polarized charge carries. If
superconductivity exists in these systems, the stable pairing symmetries are
shown to be $p+ip$ for electron doped case, and anisotropic $p+ip$ for hole
doped case. The predicted systems may provide fascinating platforms for
studying the novel properties of ferromagnetism and triplet-pairing
superconductivity as well as two-dimensional spintronics.


title: On Hilbert's 17th problem in low degree

abstract:
  Artin solved Hilbert's 17th problem, proving that a real polynomial in $n$
variables that is positive semidefinite is a sum of squares of rational
functions, and Pfister showed that only $2^n$ squares are needed. In this
paper, we investigate situations where Pfister's theorem may be improved. We
show that a real polynomial of degree $d$ in $n$ variables that is positive
semidefinite is a sum of $2^n-1$ squares of rational functions if $d\leq 2n-2$.
If $n$ is even, or equal to $3$ or $5$, this result also holds for $d=2n$.


title: Rationality, universal generation and the integral Hodge conjecture

abstract:
  We use the universal generation of algebraic cycles to relate (stable)
rationality to the integral Hodge conjecture. We show that the Chow group of
1-cycles on a cubic hypersurface is universally generated by lines.
Applications are mainly in cubic hypersurfaces of low dimensions. For example,
we show that if a generic cubic fourfold is stably rational then the
Beauville--Bogomolov form on its variety of lines, viewed as an integral Hodge
class on the self product of its variety of lines, is algebraic. In dimension
$3$ and $5$, we relate stable rationality with the geometry of the associated
intermediate Jacobian.


title:
Visual Genome: Connecting Language and Vision Using Crowdsourced Dense
  Image Annotations

abstract:
  Despite progress in perceptual tasks such as image classification, computers
still perform poorly on cognitive tasks such as image description and question
answering. Cognition is core to tasks that involve not just recognizing, but
reasoning about our visual world. However, models used to tackle the rich
content in images for cognitive tasks are still being trained using the same
datasets designed for perceptual tasks. To achieve success at cognitive tasks,
models need to understand the interactions and relationships between objects in
an image. When asked "What vehicle is the person riding?", computers will need
to identify the objects in an image as well as the relationships riding(man,
carriage) and pulling(horse, carriage) in order to answer correctly that "the
person is riding a horse-drawn carriage".
  In this paper, we present the Visual Genome dataset to enable the modeling of
such relationships. We collect dense annotations of objects, attributes, and
relationships within each image to learn these models. Specifically, our
dataset contains over 100K images where each image has an average of 21
objects, 18 attributes, and 18 pairwise relationships between objects. We
canonicalize the objects, attributes, relationships, and noun phrases in region
descriptions and questions answer pairs to WordNet synsets. Together, these
annotations represent the densest and largest dataset of image descriptions,
objects, attributes, relationships, and question answers.


title:
Threshold pion production in proton-proton collisions at NNLO in chiral
  EFT

abstract:
  The reaction $NN \to NN \pi$ offers a good testing ground for chiral
effective field theory at intermediate energies. It challenges our
understanding of the first inelastic channel in nucleon-nucleon scattering and
of the charge-symmetry breaking pattern in hadronic reactions. In our previous
studies, we presented a complete calculation of the pion-production operator
for s-wave pions up-to-and-including next-to-next-to-leading order (NNLO) in
the formulation of chiral effective field theory, which includes pions,
nucleons and $\Delta(1232)$ degrees of freedom. In this paper we calculate the
near threshold cross section for the $pp \to d \pi^{+}$ reaction by performing
the convolution of the obtained operators with nuclear wave functions based on
modern phenomenological and chiral potentials. The available chiral $NN$ wave
functions are constructed with a cutoff comparable with the momentum transfer
scale inherent in pion production reactions. Hence, a significant portion of
the dynamical intermediate-range physics is thereby cut off by them. On the
other hand, the NNLO amplitudes evaluated with phenomenological wave functions
appear to be largely independent of the $NN$ model used and give corrections to
the dominant leading order contributions as expected from dimensional analysis.
The result gives support to the counting scheme used to classify the pion
production operators, which is a precondition for a reliable investigation of
the chirally suppressed neutral pion production. The explicit inclusion of the
$\Delta(1232)$ is found to be important but smaller than expected due to
cancellations.


title:
Global Properties of Fully Convective Accretion Disks from Local
  Simulations

abstract:
  We present an approach to deriving global properties of accretion disks from
the knowledge of local solutions derived from numerical simulations based on
the shearing box approximation. The approach consists of a two-step procedure.
First a local solution valid for all values of the disk height is constructed
by piecing together an interior solution obtained numerically with an
analytical exterior radiative solution. The matching is obtained by assuming
hydrostatic balance and radiative equilibrium. Although in principle the
procedure can be carried out in general, it simplifies considerably when the
interior solution is fully convective. In these cases, the construction is
analogous to the derivation of the Hayashi tracks for protostars. The second
step consists of piecing together the local solutions at different radii to
obtain a global solution. Here we use the symmetry of the solutions with
respect to the defining dimensionless numbers--in a way similar to the use of
homology relations in stellar structure theory--to obtain the scaling
properties of the various disk quantities with radius.


title:
Robust Detection of Intensity Variant Clones in Forged and JPEG
  Compressed Images

abstract:
  Digitization of images has made image editing easier. Ease of image editing
tempted users and professionals to manipulate digital images leading to digital
image forgeries. Today digital image forgery has posed a great threat to the
authenticity of the popular digital media, the digital images. A lot of
research is going on worldwide to detect image forgery and to separate the
forged images from their authentic counterparts. This paper provides a novel
intensity invariant detection model (IIDM) for detection of intensity variant
clones that is robust against JPEG compression, noise attacks and blurring.


title:
Analogous Viscosity Equations of Granular Powders Based on Eyrings Rate
  Process Theory and Free Volume Concept

abstract:
  The viscosity concept of thermal systems is borrowed to describe the
flowability of granular powders in this article with the granular temperature
is defined analogously. Eyrings rate process theory and free volume concept,
which have been proved to be very powerful in dealing with many thermally
activated phenomena in a wide variety of fields, are utilized to derive
viscosity equations of granular powders under a simple shear. The obtained
viscosity equations are examined only with empirical experimental observations
in describing powder flowability, due to the lack of instruments and
methodology for directly determining the viscosity of granular materials. The
continuous shear thickening rather than the discontinuous shear thickening are
predicted and found to be dependent on shear rate, the cohesive energy between
particles, and the particle volume fraction, though the discontinuous shear
thickening may still occur if certain conditions are met during shear, such as
local particle volume fractions approach to the jamming point created by the
shear induced inhomogeneity. A fundamental mechanism on how dry granular
powders flow is proposed on the basis of what are demonstrated from the
viscosity equations.The work presented in this article may lay a foundation to
scale powder flowability in a more fundamental and consistent manner, at least
providing an approach to consistently define the viscosity of granular powders.
Since the same approaches are employed to derive the viscosity equations of
granular powders as used to derive viscosity equations of liquids, colloidal
suspensions, and polymeric materials, both athermal and thermal systems are
thus unified with a single methodology.


title:
Sparse Estimation of Multivariate Poisson Log-Normal Models from Count
  Data

abstract:
  Modeling data with multivariate count responses is a challenging problem due
to the discrete nature of the responses. Existing methods for univariate count
responses cannot be easily extended to the multivariate case since the
dependency among multiple responses needs to be properly accommodated. In this
paper, we propose a multivariate Poisson log-normal regression model for
multivariate data with count responses. By simultaneously estimating the
regression coefficients and inverse covariance matrix over the latent variables
with an efficient Monte Carlo EM algorithm, the proposed regression model takes
advantages of association among multiple count responses to improve the model
prediction performance. Simulation studies and applications to real world data
are conducted to systematically evaluate the performance of the proposed method
in comparison with conventional methods.


title: The effect of social welfare system based on the complex network

abstract:
  With the passage of time, the development of communication technology and
transportation broke the isolation among people. Relationship tends to be
complicated, pluralism, dynamism. In the network where interpersonal
relationship and evolved complex net based on game theory work serve
respectively as foundation architecture and theoretical model, with the
combination of game theory and regard public welfare as influencing factor, we
artificially initialize that closed network system. Through continual loop
operation of the program, we summarize the changing rule of the cooperative
behavior in the interpersonal relationship, so that we can analyze the policies
about welfare system about whole network and the relationship of frequency of
betrayal in cooperative behavior. Most analytical data come from some simple
investigations and some estimates based on internet and environment and the
study put emphasis on simulating social network and analyze influence of social
welfare system on Cooperative Behavio.


title:
Influence of substrate interaction and confinement on electric field
  induced transition in symmetric block copolymer thin films

abstract:
  In the present work, we study morphologies arising due to competing substrate
interaction, electric field and confinement effects on a symmetric diblock
copolymer. We employ a coarse grained non-local Cahn-Hilliard phenomenological
model taking into account the appropriate contributions of substrate
interaction and electrostatic field. The proposed model couples the
Ohta-Kawasaki functional with Maxwell equation of electrostatics, thus
alleviating the need for any approximate solution used in previous studies. We
calculate the phase diagram in electric field-substrate strength space for
different film thicknesses. In addition to identifying the presence of
parallel, perpendicular and mixed lamellae phases similar to analytical
calculations, we also find a region in the phase diagram where hybrid
morphologies (combination of two phases) coexist. These hybrid morphologies
arise either solely due to substrate affinity and confinement or are induced
due to the applied electric field. The dependence of the critical fields for
transition between the various phases on substrate strength, film thickness and
dielectric contrast is discussed. Some preliminary 3D results are also
presented to corroborate the presence of hybrid morphologies.


title: A Reconfigurable USAR Robot Designed for Traversing Complex 3D Terrain

abstract:
  The use of robotics in Urban Search and Rescue (USAR) is growing steadily
from their initial inception during the 2001 World Trade Centre incident.
Despite years of progress, the core design of robots currently in use for USAR
purposes has deviated little, favoring software and control development and
optimization of the basic robot template to improve performance instead.
Presented here is a novel design description of the Cricket, an advanced robot
with a broader range of physical capabilities than traditional USAR robots. By
incorporating the tracked structure of earlier robots, appreciated for energy
efficiency and robustness, into a multi-limbed walking design, the Cricket
enables the use of advanced locomotion techniques. The ability to climb over
obstacles many times the height of the robot, ascend vertical shafts without
the assistance of a tether, and traverse rough and near vertical terrain
improves the Cricket's capability to successfully locate victims in confined
spaces.


title:
Young and embedded clusters in Cygnus-X: evidence for building up the
  IMF?

abstract:
  We provide a new view on the Cygnus-X north complex by accessing for the
first time the low mass content of young stellar populations in the region.
CFHT/WIRCam camera was used to perform a deep near-IR survey of this complex,
sampling stellar masses down to ~0.1 M$_\odot$. Several analysis tools,
including a extinction treatment developed in this work, were employed to
identify and uniformly characterise a dozen unstudied young star clusters in
the area. Investigation of their mass distributions in low-mass domain revealed
a relatively uniform log-normal IMF with a characteristic mass of 0.32$\pm$0.08
M$_\odot$ and mass dispersion of 0.40$\pm$0.06. In the high mass regime, their
derived slopes showed that while the youngest clusters (age < 4 Myr) presented
slightly shallower values with respect to the Salpeter's, our older clusters (4
Myr < age < 18 Myr) showed IMF compliant values and a slightly denser stellar
population. Although possibly evidencing a deviation from an 'universal' IMF,
these results also supports a scenario where these gas dominated young clusters
gradually 'build up' their IMF by accreting low-mass stars formed in their
vicinity during their first ~3 Myr, before the gas expulsion phase, emerging at
the age of ~4 Myr with a fully fledged IMF. Finally, the derived distances to
these clusters confirmed the existence of at least 3 different star forming
regions throughout Cygnus-X north complex, at distances of 500-900 pc, 1.4-1.7
kpc and 3.0 kpc, and revealed evidence of a possible interaction between some
of these stellar populations and the Cygnus-OB2 association.


title: Stability analysis for a class of nonlinear time-changed systems

abstract:
  This paper investigates the stability of a class of differential systems
time-changed by $E_{t}$ which is the inverse of a $\beta$-stable subordinator.
In order to explore stability, a time-changed Gronwall's inequality and a
generalized It\^o formula related to both the natural time $t$ and the
time-change $E_{t}$ are developed. For different time-changed systems,
corresponding stability behaviors such as exponential sample-path stability,
$p$th moment asymptotic stability and $p$th moment exponential stability are
investigated. Also a connection between the stability of the time-changed
system and that of its corresponding non-time-changed system is revealed.


title: Jets launched at magnetar birth cannot be ignored

abstract:
  I question models for powering super energetic supernovae (SESNe) with a
magnetar central engine that do not include jets that are expected to be
launched by the magnetar progenitor. I show that under reasonable assumptions
the outflow that is expected during the formation of a magnetar can carry an
amount of energy that does not fall much below, and even surpasses, the energy
that is stored in the newly born spinning neutron star (NS). The rapidly
spinning NS and the strong magnetic fields attributed to magnetars require that
the accreted mass onto the newly born NS possesses high specific angular
momentum and strong magnetic fields. These ingredients are expected, as in many
other astrophysical objects, to form collimated outflows/jets. I argue that the
bipolar outflow in the pre-magnetar phase transfers a substantial amount of
energy to the supernova (SN) ejecta, and it cannot be ignored in models that
attribute SESNe to magnetars. I conclude that jets launched by accretion disks
and accretion belts are more likely to power SESNe than magnetars are. This
conclusion is compatible with the notion that jets might power all core
collapse SNe (CCSNe).


title:
Potential relationship of chosen major to problem solving attitudes and
  course performance

abstract:
  Introductory algebra-based physics courses frequently feature multiple
student major populations in the same course section, however, different
majors' requirements may impact students' motivations towards different aspects
of the course material, e.g. problem solving, and hence, impact course
performance. A preliminary categorization of student attitudes towards a lab
group coordinated problem solving exercise, in which students individually
reflect on their group-based problem attempt, is based upon students' written
interpretations about the usefulness of the exercise: respectively towards
intrinsic value of a problem solving framework, towards performing well in the
course, and towards less specific aspects of the exercise. The relationship
between choice of major and this preliminary categorization for a typical
algebra-based physics course is analyzed, as are trends by major and by
category type in a measure of course performance. We also discuss more in-depth
development of interpretation for the categorization construct via written
artifacts from the problem solving exercise.


title: Symmetries and Fields in Randers-Finsler spacetime

abstract:
  We study the symmetries of the Lorentz violating Randers-Finsler spacetime.
The privileged frame defined by the background vector diagonalises the deformed
mass-shell and provides an anisotropic observer transformations. The particle
Randers transformations are achieved through the Finslerian Killing equation
which also shows the equivalence between observer and particle Randers
transformation. For a constant background vector, the Randers transformations
can be regarded as a deformed directional-dependent Poincar\'e transformation.
The Randers algebra is a deformed Poincar\'e algebra whose structure
coefficients are given by the Randers metric. We propose a field theory
invariant over the Randers transformations. The dynamics exhibits nonlocal
operators which yields to Lorentz violating terms of the nonminimal SME. The
relation and implications of the Randers algebra with other Lorentz violating
theories are discussed.


title: Veronese webs and nonlinear PDEs

abstract:
  Veronese webs are closely related to bi-Hamiltonian systems, as was shown by
Gelfand and Zakharevich. Recently a correspondence between Veronese
three-dimensional webs and three-dimensional Einstein-Weyl structures of
hyper-CR type was established. The latter were parametrized by Dunajski and
Krynski via the solutions of the dispersionless Hirota equation. In this paper
we show relations of Veronese three-dimensional webs to several other
integrable equations, deform these equations preserving integrability via a
dispersionless Lax pair and compute the corresponding contact symmetries,
Backlund transformations and Einstein-Weyl structures. Realization of Veronese
webs through solutions of these deformed integrable PDE is based on a
correspondence between partially integrable Nijenhuis operators to the operator
fields with vanishing Nijenhuis tensor. This correspondence could be used to
construct a link between bi-Hamiltonian finite-dimensional integrable systems
and dispersionless integrable PDE related to the Veronese webs.


title: Efficacy of self-phoretic colloids and microswimmers

abstract:
  Within a unified formulation, encompassing self-electrophoresis,
self-diffusiophoresis, and self-thermophoresis, we provide a simple integral
kernel transforming the relevant surface flux to particle velocity for any
spheroid with axisymmetric surface activity and uniform phoretic mobility. We
define efficacy, a dimensionless efficiency-like quantity expressing the speed
resulting from unit absolute flux density on the surface, which allows a
meaningful comparison of the performance of different motor designs. For
bipartite designs with piecewise uniform flux over complementary surface
regions, the efficacy is mapped out over the entire range of geometry (discotic
through sphere to rod-like) and of bipartitioning, and intermediate aspect
ratios that maximize efficacy are identified. Comparison is made to
experimental data from the literature.


title: Computing Pretropisms for the Cyclic n-Roots Problem

abstract:
  The cyclic n-roots problem is an important benchmark problem for polynomial
system solvers. We consider the pruning of cone intersections for a polyhedral
method to compute series for the solution curves.


title: Parsimonious modeling with Information Filtering Networks

abstract:
  We introduce a methodology to construct parsimonious probabilistic models.
This method makes use of Information Filtering Networks to produce a robust
estimate of the global sparse inverse covariance from a simple sum of local
inverse covariances computed on small sub-parts of the network. Being based on
local and low-dimensional inversions, this method is computationally very
efficient and statistically robust even for the estimation of inverse
covariance of high-dimensional, noisy and short time-series. Applied to
financial data our method results computationally more efficient than
state-of-the-art methodologies such as Glasso producing, in a fraction of the
computation time, models that can have equivalent or better performances but
with a sparser inference structure. We also discuss performances with sparse
factor models where we notice that relative performances decrease with the
number of factors. The local nature of this approach allows us to perform
computations in parallel and provides a tool for dynamical adaptation by
partial updating when the properties of some variables change without the need
of recomputing the whole model. This makes this approach particularly suitable
to handle big datasets with large numbers of variables. Examples of practical
application for forecasting, stress testing and risk allocation in financial
systems are also provided.


title:
The Concentric Maclaurin Spheroid method with tides and a rotational
  enhancement of Saturn's tidal response

abstract:
  We extend to three dimensions the Concentric Maclaurin Spheroid method for
obtaining the self-consistent shape and gravitational field of a rotating
liquid planet, to include a tidal potential from a satellite. We exhibit, for
the first time, the important effect of the planetary rotation rate on tidal
response of gas giants. Simulations of planets with fast rotation rates like
those of Jupiter and Saturn, exhibit significant changes in calculated tidal
love numbers $k_{nm}$ when compared with non-rotating bodies. A test model of
Saturn fitted to observed zonal gravitational multipole harmonics yields
$k_2=0.413$, consistent with a recent observational determination from Cassini
astrometry data (Lainey et al., 2016). The calculated love number is robust
under reasonable assumptions of interior rotation rate, satellite parameters,
and details of Saturn's interior structure. The method is benchmarked against
several published test cases.


title: Computing approximate PSD factorizations

abstract:
  We give an algorithm for computing approximate PSD factorizations of
nonnegative matrices. The running time of the algorithm is polynomial in the
dimensions of the input matrix, but exponential in the PSD rank and the
approximation error. The main ingredient is an exact factorization algorithm
when the rows and columns of the factors are constrained to lie in a general
polyhedron. This strictly generalizes nonnegative matrix factorizations which
can be captured by letting this polyhedron to be the nonnegative orthant.


title: Fermi GBM signal contemporaneous with GW150914 - an unlikely association

abstract:
  We argue that the physical constraints required by the association of the
Fermi GBM signal contemporaneous with GW150914 - radiative power of $10^{49} $
erg s$^{-1}$, and corresponding magnetic fields on the black hole of the order
of $10^{12}$ Gauss - are astrophysical highly implausible. Combined with the
relatively high random probability of coincidence of 0.22 percents, we conclude
that the electromagnetic signal is likely unrelated to the BH merger.


title:
Aspects of Holographic Entanglement at Finite Temperature and Chemical
  Potential

abstract:
  We investigate the behavior of entanglement entropy at finite temperature and
chemical potential for strongly coupled large-N gauge theories in
$d$-dimensions ($d\ge 3$) that are dual to Anti-de Sitter-Reissner-Nordstrom
geometries in $(d+1)-$dimensions, in the context of gauge-gravity duality. We
develop systematic expansions based on the Ryu-Takayanagi prescription that
enable us to derive analytic expressions for entanglement entropy and mutual
information in different regimes of interest. Consequently, we identify the
specific regions of the bulk geometry that contribute most significantly to the
entanglement entropy of the boundary theory at different limits. We define a
scale, dubbed as the effective temperature, which determines the behavior of
entanglement in different regimes. At high effective temperature, entanglement
entropy is dominated by the thermodynamic entropy, however, mutual information
subtracts out this contribution and measures the actual quantum entanglement.
Finally, we study the entanglement/disentanglement transition of mutual
information in the presence of chemical potential which shows that the quantum
entanglement between two sub-regions decreases with the increase of chemical
potential.


title: High-pressure superconducting state in hydrogen

abstract:
  The paper determines the thermodynamic parameters of the superconducting
state in the metallic atomic hydrogen under the pressure at $1$ TPa, $1.5$ TPa,
and $2.5$ TPa. The calculations were conducted in the framework of the
Eliashberg formalism. It has been shown that the critical temperature is very
high (in the range from $301.2$ K to $437.3$ K), as well as high are the values
of the electron effective mass (from $3.43$ $m_{e}$ to $6.88$ $m_{e}$), where
$m_{e}$ denotes the electron band mass. The ratio of the low-temperature energy
gap to the critical temperature explicitly violates the predictions of the BCS
theory: $2\Delta\left(0\right)/k_{B}T_{C}\in\left<4.84,5.85\right>$.
Additionally, the free energy difference between the superconducting and normal
state, the thermodynamic critical field, and the specific heat of the
superconducting state have been determined. Due to the significant
strong-coupling and retardation effects those quantities cannot be correctly
described in the framework of the BCS theory.


title: The Analytic Renormalization Group

abstract:
  Finite temperature Euclidean two-point functions in quantum mechanics or
quantum field theory are characterized by a discrete set of Fourier
coefficients $G_{k}$, $k\in\mathbb Z$, associated with the Matsubara
frequencies $\nu_{k}=2\pi k/\beta$. We show that analyticity implies that the
coefficients $G_{k}$ must satisfy an infinite number of model-independent
linear equations that we write down explicitly. In particular, we construct
"Analytic Renormalization Group" linear maps $\mathsf A_{\mu}$ which, for any
choice of cut-off $\mu$, allow to express the low energy Fourier coefficients
for $|\nu_{k}|<\mu$ (with the possible exception of the zero mode $G_{0}$),
together with the real-time correlators and spectral functions, in terms of the
high energy Fourier coefficients for $|\nu_{k}|\geq\mu$. Operating a simple
numerical algorithm, we show that the exact universal linear constraints on
$G_{k}$ can be used to systematically improve any random approximate data set
obtained, for example, from Monte-Carlo simulations. Our results are
illustrated on several explicit examples.

categories: hep-lat cond-mat.stat-mech hep-ph hep-th math-ph math.MP


title: Nuclear structure theory of the heaviest nuclei

abstract:
  The current status of the application of covariant density functional theory
to the description of actinides and superheavy nuclei is reviewed. The
achievements and open problems are discussed.


title: Interfacial Dynamics of Thin Viscoelastic Films and Drops

abstract:
  We present a computational investigation of thin viscoelastic films and drops
on a solid substrate subject to the van der Waals interaction force, in two
spatial dimensions. The governing equations are obtained within a long-wave
approximation of the Navier-Stokes equations with Jeffreys model for
viscoelastic stresses. We investigate the effects of viscoelasticity, Newtonian
viscosity, and the substrate slippage on the dynamics of thin viscoelastic
films. We also study the effects of viscoelasticity on drops that spread or
recede on a prewetted substrate. For dewetting films, the numerical results
show the presence of multiple secondary droplets for higher values of
elasticity, consistently with experimental findings. For drops, we find that
elastic effects lead to deviations from the Cox-Voinov law for partially
wetting fluids. In general, elastic effects enhance spreading, and suppress
retraction, compared to Newtonian ones.


title: Post-selection inference for L1-penalized likelihood models

abstract:
  We present a new method for post-selection inference for L1 (lasso)-penalized
likelihood models, including generalized regression models. Our approach
generalizes the post-selection framework presented in Lee et al (2014). The
method provides p-values and confidence intervals that are asymptotically
valid, conditional on the inherent selection done by the lasso. We present
applications of this work to (regularized) logistic regression, Cox's
proportional hazards model and the graphical lasso.


title:
Improved $L^2$ estimate for gradient schemes, and super-convergence of
  the TPFA finite volume scheme

abstract:
  The gradient discretisation method is a generic framework that is applicable
to a number of schemes for diffusion equations, and provides in particular
generic error estimates in $L^2$ and $H^1$-like norms. In this paper, we
establish an improved $L^2$ error estimate for gradient schemes. This estimate
is applied to a family of gradient schemes, namely, the Hybrid Mimetic Mixed
(HMM) schemes, and yields an $\mathcal O(h^2)$ super-convergence rate in $L^2$
norm, provided local compensations occur between the cell points used to define
the scheme and the centers of mass of the cells. To establish this result, a
modified HMM method is designed by just changing the quadrature of the source
term; this modified HMM enjoys a super-convergence result even on meshes
without local compensations. Finally, the link between HMM and Two-Point Flux
Approximation (TPFA) finite volume schemes is exploited to partially answer a
long-standing conjecture on the super-convergence of TPFA schemes.


title:
SqueezeNet: AlexNet-level accuracy with 50x fewer parameters and <0.5MB
  model size

abstract:
  Recent research on deep neural networks has focused primarily on improving
accuracy. For a given accuracy level, it is typically possible to identify
multiple DNN architectures that achieve that accuracy level. With equivalent
accuracy, smaller DNN architectures offer at least three advantages: (1)
Smaller DNNs require less communication across servers during distributed
training. (2) Smaller DNNs require less bandwidth to export a new model from
the cloud to an autonomous car. (3) Smaller DNNs are more feasible to deploy on
FPGAs and other hardware with limited memory. To provide all of these
advantages, we propose a small DNN architecture called SqueezeNet. SqueezeNet
achieves AlexNet-level accuracy on ImageNet with 50x fewer parameters.
Additionally, with model compression techniques we are able to compress
SqueezeNet to less than 0.5MB (510x smaller than AlexNet).
  The SqueezeNet architecture is available for download here:
https://github.com/DeepScale/SqueezeNet


title: Critical Field Determination in Organic Antiferromagnet F4BImNN

abstract:
  A combination of magnetic heat capacity measurements versus temperature under
multiple fixed external fields using a polycrystalline sample, plus easy and
hard axis aligned magnetization versus field measurements using a single
crystal of the radical
2-(4,5,6,7-tetrafluorobenzimidazol-2-yl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-3-oxide-1-oxyl)
at multiple fixed temperatures below 0.75 K, confirmed a zero-field Neel
temperature of TN(0) = 0.73 K, with extrapolated 0 K critical field parameters
of Hc(parallel) = 170 Oe and Hc(perpendicular) = 306 Oe. Assuming the
previously determined 1D intrachain ferromagnetic exchange interaction of J =
+22 K between radicals (Hamiltonian H = -2J {\Sigma}Si . Sj), , the interchain
exchange in antiferromagnetic with 2zJinter = -0.09 K.


title: The Possibilities and Limitations of Private Prediction Markets

abstract:
  We consider the design of private prediction markets, financial markets
designed to elicit predictions about uncertain events without revealing too
much information about market participants' actions or beliefs. Our goal is to
design market mechanisms in which participants' trades or wagers influence the
market's behavior in a way that leads to accurate predictions, yet no single
participant has too much influence over what others are able to observe. We
study the possibilities and limitations of such mechanisms using tools from
differential privacy. We begin by designing a private one-shot wagering
mechanism in which bettors specify a belief about the likelihood of a future
event and a corresponding monetary wager. Wagers are redistributed among
bettors in a way that more highly rewards those with accurate predictions. We
provide a class of wagering mechanisms that are guaranteed to satisfy
truthfulness, budget balance in expectation, and other desirable properties
while additionally guaranteeing epsilon-joint differential privacy in the
bettors' reported beliefs, and analyze the trade-off between the achievable
level of privacy and the sensitivity of a bettor's payment to her own report.
We then ask whether it is possible to obtain privacy in dynamic prediction
markets, focusing our attention on the popular cost-function framework in which
securities with payments linked to future events are bought and sold by an
automated market maker. We show that under general conditions, it is impossible
for such a market maker to simultaneously achieve bounded worst-case loss and
epsilon-differential privacy without allowing the privacy guarantee to degrade
extremely quickly as the number of trades grows, making such markets
impractical in settings in which privacy is valued. We conclude by suggesting
several avenues for potentially circumventing this lower bound.


title: Higher order Quasi-Monte Carlo integration for Bayesian Estimation

abstract:
  We analyze combined Quasi-Monte Carlo quadrature and Finite Element
approximations in Bayesian estimation of solutions to countably-parametric
operator equations with holomorphic dependence on the parameters as considered
in [Cl.~Schillings and Ch.~Schwab: Sparsity in Bayesian Inversion of Parametric
Operator Equations. Inverse Problems, {\bf 30}, (2014)]. Such problems arise in
numerical uncertainty quantification and in Bayesian inversion of operator
equations with distributed uncertain inputs, such as uncertain coefficients,
uncertain domains or uncertain source terms and boundary data. We show that the
parametric Bayesian posterior densities belong to a class of weighted Bochner
spaces of functions of countably many variables, with a particular structure of
the QMC quadrature weights: up to a (problem-dependent, and possibly large)
finite dimension $S$ product weights can be used, and beyond this dimension,
weighted spaces with so-called SPOD weights are used to describe the solution
regularity. We establish error bounds for higher order Quasi-Monte Carlo
quadrature for the Bayesian estimation based on [J.~Dick, Q.T.~LeGia and
Ch.~Schwab, Higher order Quasi-Monte Carlo integration for holomorphic,
parametric operator equations, Report 2014-23, SAM, ETH Z\"urich]. It implies,
in particular, regularity of the parametric solution and of the
countably-parametric Bayesian posterior density in SPOD weighted spaces. This,
in turn, implies that the Quasi-Monte Carlo quadrature methods in [J. Dick,
F.Y.~Kuo, Q.T.~Le Gia, D.~Nuyens, Ch.~Schwab, Higher order QMC Galerkin
discretization for parametric operator equations, SINUM (2014)] are applicable
to these problem classes, with dimension-independent convergence rates
$\calO(N^{-1/p})$ of $N$-point HoQMC approximated Bayesian estimates, where
$0<p<1$ depends only on the sparsity class of the uncertain input in the
Bayesian estimation.


title: Uplink Performance of Wideband Massive MIMO with One-Bit ADCs

abstract:
  Analog-to-digital converters (ADCs) stand for a significant part of the total
power consumption in a massive MIMO base station. One-bit ADCs are one way to
reduce power consumption. This paper presents an analysis of the spectral
efficiency of single-carrier and OFDM transmission in massive MIMO systems that
use one-bit ADCs. A closed-form achievable rate, i.e., a lower bound on
capacity, is derived for a wideband system with a large number of channel taps
that employs low-complexity linear channel estimation and symbol detection.
Quantization results in two types of error in the symbol detection. The
circularly symmetric error becomes Gaussian in massive MIMO and vanishes as the
number of antennas grows. The amplitude distortion, which severely degrades the
performance of OFDM, is caused by variations between symbol durations in
received interference energy. As the number of channel taps grows, the
amplitude distortion vanishes and OFDM has the same performance as
single-carrier transmission. A main conclusion of this paper is that wideband
massive MIMO systems work well with one-bit ADCs.


title: Constrained Generalized Delaunay Graphs Are Plane Spanners

abstract:
  We look at generalized Delaunay graphs in the constrained setting by
introducing line segments which the edges of the graph are not allowed to
cross. Given an arbitrary convex shape $C$, a constrained Delaunay graph is
constructed by adding an edge between two vertices $p$ and $q$ if and only if
there exists a homothet of $C$ with $p$ and $q$ on its boundary that does not
contain any other vertices visible to $p$ and $q$. We show that, regardless of
the convex shape $C$ used to construct the constrained Delaunay graph, there
exists a constant $t$ (that depends on $C$) such that it is a plane $t$-spanner
of the visibility graph. Furthermore, we reduce the upper bound on the spanning
ratio for the special case where the empty convex shape is an arbitrary
rectangle to $\sqrt{2} \cdot \left( 2 l/s + 1 \right)$, where $l$ and $s$ are
the length of the long and short side of the rectangle.


title:
An Intelligent QoS Identification for Untrustworthy Web Services Via
  Two-phase Neural Networks

abstract:
  QoS identification for untrustworthy Web services is critical in QoS
management in the service computing since the performance of untrustworthy Web
services may result in QoS downgrade. The key issue is to intelligently learn
the characteristics of trustworthy Web services from different QoS levels, then
to identify the untrustworthy ones according to the characteristics of QoS
metrics. As one of the intelligent identification approaches, deep neural
network has emerged as a powerful technique in recent years. In this paper, we
propose a novel two-phase neural network model to identify the untrustworthy
Web services. In the first phase, Web services are collected from the published
QoS dataset. Then, we design a feedforward neural network model to build the
classifier for Web services with different QoS levels. In the second phase, we
employ a probabilistic neural network (PNN) model to identify the untrustworthy
Web services from each classification. The experimental results show the
proposed approach has 90.5% identification ratio far higher than other
competing approaches.


title:
Classical realization of dispersion-canceled, artifact-free, and
  background-free optical coherence tomography

abstract:
  Quantum-optical coherence tomography (Q-OCT) provides a dispersion-canceled
axial-imaging method, but its practical use is limited by the weakness of the
light source and by artifacts in the images. A recent study using chirped-pulse
interferometry (CPI) has demonstrated dispersion-canceled and artifact-free OCT
with a classical system; however, unwanted background signals still remain
after removing the artifacts. Here, we propose a classical optical method that
realizes dispersion-canceled, artifact-free, and background-free OCT. We employ
a time-reversed system for Q-OCT with transform-limited input laser pulses to
achieve dispersion-canceled OCT with a classical system. We have also
introduced a subtraction method to remove artifacts and background signals.
With these methods, we experimentally demonstrated dispersion-canceled,
artifact-free, and background-free axial imaging of a coverglass and
cross-sectional imaging of the surface of a coin.


title: Z-stability in Constructive Analysis

abstract:
  We introduce Z-stability, a notion capturing the intuition that if a function
f maps a metric space into a normed space and if the norm of f(x) is small,
then x is close to a zero of f. Working in Bishop's constructive setting, we
first study pointwise versions of Z-stability and the related notion of good
behaviour for functions. We then present a recursive counterexample to the
classical argument for passing from pointwise Z-stability to a uniform version
on compact metric spaces. In order to effect this passage constructively, we
bring into play the positivity principle, equivalent to Brouwer's fan theorem
for detachable bars, and the limited anti-Specker property, an intuitionistic
counterpart to sequential compactness. The final section deals with connections
between the limited anti-Specker property, positivity properties, and
(potentially) Brouwer's fan theorem for detachable bars.


title:
On the coupling between buoyancy forces and electroconvective
  instability near ion-selective surfaces

abstract:
  Recent investigations have revealed that ion transport from aqueous
electrolytes to ion-selective surfaces is subject to electroconvective
instability that stems from coupling of hydrodynamics with electrostatic
forces. Electroconvection is shown to enhance ion mixing and the net rate of
transport. However, systems subject to electroconvection inherently involve
fluid density variation set by salinity gradient in the bulk fluid. In this
study we thoroughly examine the interplay of gravitational convection and
chaotic electroconvection. Our results reveal that buoyant forces can
significantly influence the transport rates, otherwise set by
electroconvection, when the Rayleigh number $Ra$ of the system exceeds a value
$Ra \sim 1000$. We show that buoyancy forces can significantly alter the flow
patterns in these systems. When the buoyancy acts in the stabilizing direction,
it limits the extent of penetration of electroconvection, but without
eliminating it. When the buoyancy destabilizes the flow, it alters the
electroconvective patterns by introducing upward and downward fingers of
respectively light and heavy fluid.


title: Exact solutions for logistic reaction-diffusion in biology

abstract:
  Reaction-diffusion equations with a nonlinear source have been widely used to
model various systems, with particular application to biology. Here, we provide
a solution technique for these types of equations in $N$-dimensions. The
nonclassical symmetry method leads to a single relationship between the
nonlinear diffusion coefficient and the nonlinear reaction term; the subsequent
solutions for the Kirchhoff variable are exponential in time (either growth or
decay) and satisfy the linear Helmholtz equation in space. Example solutions
are given in two dimensions for particular parameter sets for both quadratic
and cubic reaction terms.


title:
High sensitivity optical Faraday-magnetometry with intracavity
  electromagnetically induced transparency

abstract:
  We suggest a multiatom cavity quantum electrodynamics system for the weak
magnetic field detection based on Faraday rotation with intracavity
electromagnetically induced transparency. Our study demonstrates that the
collective coupling between the cavity modes and the atomic ensemble can be
used to improve the sensitivity. With single probe photon input, the
sensitivity is inversely proportional to the number of atoms, and the
sensitivity with 0.7(5)~nT/$\sqrt{\rm Hz}$ could be attained. With multiphoton
measurement, our numerical calculations show that the magnetic field
sensitivity can be improved to 4.7(9)~fT/$\sqrt{\rm Hz}$.


title: Stable and Unstable Regimes of Mass Accretion onto RW Aur A

abstract:
  We present monitoring observations of the active T Tauri star RW Aur, from
2010 October to 2015 January, using optical high-resolution (R>10000)
spectroscopy with CFHT-ESPaDOnS. Optical photometry in the literature shows
bright, stable fluxes over most of this period, with lower fluxes (by 2-3 mag.)
in 2010 and 2014. In the bright period our spectra show clear photospheric
absorption, complicated variation in the Ca II 8542 A emission}profile shapes,
and a large variation in redshifted absorption in the O I 7772 and 8446 A and
He I 5876 A lines, suggesting unstable mass accretion during this period. In
contrast, these line profiles are relatively uniform during the faint periods,
suggesting stable mass accretion. During the faint periods the photospheric
absorption lines are absent or marginal, and the averaged Li I profile shows
redshifted absorption due to an inflow. We discuss (1) occultation by
circumstellar material or a companion and (2) changes in the activity of mass
accretion to explain the above results, together with near-infrared and X-ray
observations from 2011-2015. Neither scenario can simply explain all the
observed trends, and more theoretical work is needed to further investigate
their feasibilities.


title: On Study of the Binarized Deep Neural Network for Image Classification

abstract:
  Recently, the deep neural network (derived from the artificial neural
network) has attracted many researchers' attention by its outstanding
performance. However, since this network requires high-performance GPUs and
large storage, it is very hard to use it on individual devices. In order to
improve the deep neural network, many trials have been made by refining the
network structure or training strategy. Unlike those trials, in this paper, we
focused on the basic propagation function of the artificial neural network and
proposed the binarized deep neural network. This network is a pure binary
system, in which all the values and calculations are binarized. As a result,
our network can save a lot of computational resource and storage. Therefore, it
is possible to use it on various devices. Moreover, the experimental results
proved the feasibility of the proposed network.


title: Recursive cubes of rings as models for interconnection networks

abstract:
  We study recursive cubes of rings as models for interconnection networks. We
first redefine each of them as a Cayley graph on the semidirect product of an
elementary abelian group by a cyclic group in order to facilitate the study of
them by using algebraic tools. We give an algorithm for computing shortest
paths and the distance between any two vertices in recursive cubes of rings,
and obtain the exact value of their diameters. We obtain sharp bounds on the
Wiener index, vertex-forwarding index, edge-forwarding index and bisection
width of recursive cubes of rings. The cube-connected cycles and cube-of-rings
are special recursive cubes of rings, and hence all results obtained in the
paper apply to these well-known networks.


title:
Hypergeometric Differential Equation and New Identities for the
  Coefficients of N{\o}rlund and B\"uhring

abstract:
  The fundamental set of solutions of the generalized hypergeometric
differential equation in the neighborhood of unity has been built by N{\o}rlund
in 1955. The behavior of the generalized hypergeometric function in the
neighborhood of unity has been described in the beginning of 1990s by
B\"uhring, Srivastava and Saigo. In the first part of this paper we review
their results rewriting them in terms of Meijer's $G$-function and explaining
the interconnections between them. In the second part we present new formulas
and identities for the coefficients that appear in the expansions of Meijer's
$G$-function and generalized hypergeometric function around unity. Particular
cases of these identities include known and new relations for Thomae's
hypergeometric function and forgotten Hermite's identity for the sine function.


title: Student understanding of symmetry and Gauss's law of electricity

abstract:
  We investigate the difficulties that students in calculus-based introductory
physics courses have with the concepts of symmetry, electric field, and
electric flux which are important for applying Gauss's law. The determination
of the electric field using Gauss's law requires determining the symmetry of a
particular charge distribution and predicting the direction of the electric
field everywhere if a high symmetry exists. Effective application of Gauss's
law implicitly requires understanding the principle of superposition for
electric fields. Helping students learn when Gauss's law can be readily applied
to determine the strength of the electric field, and then helping them learn to
determine the appropriate shape of Gaussian surfaces if sufficient symmetry
exists, can help develop their reasoning and problem-solving skills. We
administered free-response and multiple-choice questions and conducted
interviews with individual students using a think-aloud protocol to elucidate
the difficulties that students have with the concepts of symmetry, electric
field, and electric flux. We also developed a multiple-choice test that targets
these conceptual issues to obtain quantitative information about their
difficulties and administered it to 541 students in the introductory
calculus-based physics courses and to upper-level undergraduates in an
electricity and magnetism course and to graduate students enrolled in a TA
seminar course. We find that undergraduate students have many common
difficulties with these concepts.


title: How Deep Neural Networks Can Improve Emotion Recognition on Video Data

abstract:
  We consider the task of dimensional emotion recognition on video data using
deep learning. While several previous methods have shown the benefits of
training temporal neural network models such as recurrent neural networks
(RNNs) on hand-crafted features, few works have considered combining
convolutional neural networks (CNNs) with RNNs. In this work, we present a
system that performs emotion recognition on video data using both CNNs and
RNNs, and we also analyze how much each neural network component contributes to
the system's overall performance. We present our findings on videos from the
Audio/Visual+Emotion Challenge (AV+EC2015). In our experiments, we analyze the
effects of several hyperparameters on overall performance while also achieving
superior performance to the baseline and other competing methods.


title: A disconnected deformation space of rational maps

abstract:
  Let $f:(\mathbb{P}^1,P)\to(\mathbb{P}^1,P)$ be a postcritically finite
rational map with postcritical set $P$. William Thurston showed that $f$
induces a holomorphic pullback map $\sigma_f:\mathcal{T}_P\to\mathcal{T}_P$ on
the Teichm\"uller space ${\mathcal T}_P:=\mathrm{Teich}(\mathbb{P}^1,P)$. If
$f$ is not a flexible Latt\`es map, Thurston proved that $\sigma_f$ has a
unique fixed point. In his PhD thesis, Adam Epstein generalized Thurston's
ideas and defined a deformation space associated to a rational map
$f:(\mathbb{P}^1,A)\to (\mathbb{P}^1,B)$ where $A \subseteq B$, allowing for
maps $f$ which are not necessarily postcritically finite. By definition, the
deformation space $\mathrm{Def}_B^A(f)\subseteq \mathcal{T}_B$ is the locus
where the pullback map $\sigma_f:\mathcal{T}_B\to\mathcal{T}_A$ and the
forgetful map $\sigma_A^B:\mathcal{T}_B\to\mathcal{T}_A$ agree. Using purely
local arguments, Epstein showed that $\mathrm{Def}_B^A(f)$ is a smooth analytic
submanifold of $\mathcal{T}_B$ of dimension $|B-A|$. In this article, we
investigate the question of whether $\mathrm{Def}_B^A(f)$ is connected. We
exhibit a family of quadratic rational maps for which the associated
deformation spaces are disconnected; in fact, each has infinitely many
components.


title: Betti Spectral Gluing

abstract:
  Given a complex reductive group G, Borel subgroup B, and topological surface
S with boundary dS, we study the "Betti spectral category" DCoh_N(Loc_G(S, dS))
of coherent sheaves with nilpotent singular support on the character stack of
G-local systems on S with B-reductions along dS. Modifications along the
components of dS endow this category with commuting actions of the affine Hecke
category H_G in its realization as coherent sheaves on the Steinberg stack. We
prove a "spectral Verlinde formula" identifying the result of gluing two
boundary components with the Hochschild homology of the corresponding
H_G-bimodule structure. The equivalence is compatible with Wilson line
operators (the action of Perf(Loc_G(S)) realized by Hecke modifications at
points) as well as Verlinde loop operators (the action of the center of H_G
realized by Hecke modifications along closed loops). The result reduces the
calculation of such "Betti spectral categories" to the case of disks,
cylinders, pairs of pants, and the M"obius band.


title: Understanding discs in binary YSOs: detailed modelling of VV CrA

abstract:
  Given that a majority of stars form in multiple systems, in order to fully
understand the star- and planet-formation processes we must seek to understand
them in multiple stellar systems. With this in mind, we present an analysis of
the enigmatic binary T-Tauri system VV Corona Australis, in which both
components host discs, but only one is visible at optical wavelengths. We seek
to understand the peculiarities of this system by searching for a model for the
binary which explains all the available continuum observations of the system.
We present new mid-infrared interferometry and near-infrared spectroscopy along
with archival millimetre-wave observations, which resolve the binary at 1.3mm
for the first time. We compute a grid of pre-main-sequence radiative transfer
models and calculate their posterior probabilities given the observed spectral
energy distributions and mid-infrared interferometric visibilities of the
binary components, beginning with the assumption that the only differences
between the two components are their inclination and position angles. Our
best-fitting solution corresponds to a relatively low luminosity T-tauri
binary, with each component's disc having a large scale height and viewed at
moderate inclination ($\sim 50^\circ$), with the infrared companion inclined by
$\sim 5^\circ$ degrees more than the primary. Comparing the results of our
model to evolutionary models suggests stellar masses $\sim 1.7$M$_\odot$ and an
age for the system of 3.5Myr, towards the upper end of previous estimates.
Combining these results with accretion indicators from near-IR spectroscopy, we
determine an accretion rate of 4.0$\times 10^{-8}$M$_\odot$ yr$^{-1}$ for the
primary. We suggest that future observations of VV~CrA and similar systems
should prioritise high angular resolution sub-mm and near-IR imaging of the
discs and high resolution optical/NIR spectroscopy of the central stars.


title: Transient X-ray source population in the Magellanic-type galaxy NGC 55

abstract:
  We present the spectral and temporal properties of 15 candidate transient
X-ray sources detected in archival {\it XMM-Newton} and {\it Chandra}
observations of the nearby Magellanic-type, SB(s)m galaxy NGC 55. On the basis
of an X-ray color classification scheme, the majority of the sources may be
identified as X-ray binaries (XRBs), and six sources are soft, including a
likely supernova remnant. We perform a detailed spectral and variability
analysis of the data for two bright candidate XRBs. Both sources displayed
strong short-term X-ray variability, and their X-ray spectra and hardness
ratios are consistent with those of XRBs. These results, combined with their
high X-ray luminosities ($\sim 10^{38}~\rm erg~s^{-1}$), strongly suggest that
they are black hole (BH) binaries. Seven less luminous sources have spectral
properties consistent with those of neutron star or BH XRBs in both normal and
high-rate accretion modes, but one of them is the likely counterpart to a
background galaxy (because of positional coincidence). From the spectral
analysis, we find that the six soft sources are candidate super soft sources
(SSSs), with dominant emission in the soft (0.3--2 keV) X-ray band. Archival
{\it Hubble Space Telescope} optical images for 7 sources are available, and
the data suggest that most of them are likely to be high-mass XRBs. Our
analysis has revealed the heterogeneous nature of the transient population in
NGC 55 (6 high-mass XRBs, 1 low-mass XRBs, 6 SSSs, 1 active galactic nucleus),
helping establish the similarity of the X-ray properties of this galaxy to
those of other Magellanic-type galaxies.


title: Representing the big tilting sheaves as holomorphic Morse branes

abstract:
  We introduce Morse branes in the Fukaya category of a holomorphic symplectic
manifold, with the goal of constructing tilting objects in the category. We
give a construction of a class of Morse branes in the cotangent bundles, and
apply it to give the holomorphic branes that represent the big tilting sheaves
on flag varieties.


title: Automatic Moth Detection from Trap Images for Pest Management

abstract:
  Monitoring the number of insect pests is a crucial component in
pheromone-based pest management systems. In this paper, we propose an automatic
detection pipeline based on deep learning for identifying and counting pests in
images taken inside field traps. Applied to a commercial codling moth dataset,
our method shows promising performance both qualitatively and quantitatively.
Compared to previous attempts at pest detection, our approach uses no
pest-specific engineering which enables it to adapt to other species and
environments with minimal human effort. It is amenable to implementation on
parallel hardware and therefore capable of deployment in settings where
real-time performance is required.


title:
Joint Measurement of Lensing-Galaxy Correlations Using SPT and DES SV
  Data

abstract:
  We measure the correlation of galaxy lensing and cosmic microwave background
lensing with a set of galaxies expected to trace the matter density field. The
measurements are performed using pre-survey Dark Energy Survey (DES) Science
Verification optical imaging data and millimeter-wave data from the 2500 square
degree South Pole Telescope Sunyaev-Zel'dovich (SPT-SZ) survey. The two
lensing-galaxy correlations are jointly fit to extract constraints on
cosmological parameters, constraints on the redshift distribution of the lens
galaxies, and constraints on the absolute shear calibration of DES galaxy
lensing measurements. We show that an attractive feature of these fits is that
they are fairly insensitive to the clustering bias of the galaxies used as
matter tracers. The measurement presented in this work confirms that DES and
SPT data are consistent with each other and with the currently favored
$\Lambda$CDM cosmological model. It also demonstrates that joint lensing-galaxy
correlation measurement considered here contains a wealth of information that
can be extracted using current and future surveys.


title:
Detector-decoy quantum key distribution without monitoring signal
  disturbance

abstract:
  The round-robin differential phase-shift quantum key distribution protocol
provides a secure way to exchange private information without monitoring
conventional disturbances and still maintains a high tolerance of noise, making
it desirable for practical implementations of quantum key distribution.
However, photon number resolving detectors are required to ensure that the
detected signals are single photons in the original protocol. Here, we adopt
the detector-decoy method and give the bounds to the fraction of detected
events from single photons. Utilizing the advantages of the protocol, we
provide a practical method of performing the protocol with desirable
performances requiring only threshold single-photon detectors.


title:
Near Transform-Limited Single Photons from an Efficient Solid-State
  Quantum Emitter

abstract:
  By pulsed s-shell resonant excitation of a single quantum dot-micropillar
system, we generate long streams of a thousand of near transform-limited single
photons with high mutual indistinguishability. Hong-Ou-Mandel interference of
two photons are measured as a function of their emission time separation
varying from 13 ns to 14.7 {\mu}s, where the visibility slightly drops from
95.9(2)% to a plateau of 92.1(5)% through a slow dephasing process occurring at
time scale of 0.7 {\mu}s. Temporal and spectral analysis reveal the pulsed
resonance fluorescence single photons are close to transform limit, which are
readily useful for multi-photon entanglement and interferometry experiments.


title: Discrete Distribution Estimation under Local Privacy

abstract:
  The collection and analysis of user data drives improvements in the app and
web ecosystems, but comes with risks to privacy. This paper examines discrete
distribution estimation under local privacy, a setting wherein service
providers can learn the distribution of a categorical statistic of interest
without collecting the underlying data. We present new mechanisms, including
hashed K-ary Randomized Response (KRR), that empirically meet or exceed the
utility of existing mechanisms at all privacy levels. New theoretical results
demonstrate the order-optimality of KRR and the existing RAPPOR mechanism at
different privacy regimes.


title: The Myopia of Crowds: A Study of Collective Evaluation on Stack Exchange

abstract:
  Crowds can often make better decisions than individuals or small groups of
experts by leveraging their ability to aggregate diverse information. Question
answering sites, such as Stack Exchange, rely on the "wisdom of crowds" effect
to identify the best answers to questions asked by users. We analyze data from
250 communities on the Stack Exchange network to pinpoint factors affecting
which answers are chosen as the best answers. Our results suggest that, rather
than evaluate all available answers to a question, users rely on simple
cognitive heuristics to choose an answer to vote for or accept. These cognitive
heuristics are linked to an answer's salience, such as the order in which it is
listed and how much screen space it occupies. While askers appear to depend
more on heuristics, compared to voting users, when choosing an answer to accept
as the most helpful one, voters use acceptance itself as a heuristic: they are
more likely to choose the answer after it is accepted than before that very
same answer was accepted. These heuristics become more important in explaining
and predicting behavior as the number of available answers increases. Our
findings suggest that crowd judgments may become less reliable as the number of
answers grow.


title:
Capturing the dynamical repertoire of single neurons with generalized
  linear models

abstract:
  A key problem in computational neuroscience is to find simple, tractable
models that are nevertheless flexible enough to capture the response properties
of real neurons. Here we examine the capabilities of recurrent point process
models known as Poisson generalized linear models (GLMs). These models are
defined by a set of linear filters, a point nonlinearity, and conditionally
Poisson spiking. They have desirable statistical properties for fitting and
have been widely used to analyze spike trains from electrophysiological
recordings. However, the dynamical repertoire of GLMs has not been
systematically compared to that of real neurons. Here we show that GLMs can
reproduce a comprehensive suite of canonical neural response behaviors,
including tonic and phasic spiking, bursting, spike rate adaptation, type I and
type II excitation, and two forms of bistability. GLMs can also capture
stimulus-dependent changes in spike timing precision and reliability that mimic
those observed in real neurons, and can exhibit varying degrees of
stochasticity, from virtually deterministic responses to greater-than-Poisson
variability. These results show that Poisson GLMs can exhibit a wide range of
dynamic spiking behaviors found in real neurons, making them well suited for
qualitative dynamical as well as quantitative statistical studies of
single-neuron and population response properties.


title:
Improving Students' Conceptual Understanding of Conductors and
  Insulators

abstract:
  We examine the difficulties that introductory physics students, undergraduate
physics majors, and physics graduate students have with concepts related to
conductors and insulators covered in introductory physics by giving written
tests and interviewing a subset of students. We find that even graduate
students have serious difficulties with these concepts. We develop tutorials
related to these topics and evaluate their effectiveness by comparing the
performance on written pre-/post-tests and interviews of students who received
traditional instruction vs. those who learned using tutorials.


title:
Beyond Gaussian pair fluctuation theory for strongly interacting Fermi
  gases

abstract:
  Interacting Fermi systems in the strongly correlated regime play a
fundamental role in many areas of physics and are of particular interest to the
condensed matter community. Though weakly inter- acting fermions are
understood, strongly correlated fermions are difficult to describe
theoretically as there is no small interaction parameter to expand about.
Existing strong coupling theories rely heavily on the so-called many-body
T-matrix approximation that sums ladder-type Feynman diagrams. Here, by
acknowledging the fact that the effective interparticle interaction (i.e., the
vertex function) becomes smaller above three dimensions, we propose an
alternative way to reorganize Feynman diagrams and develop a theoretical
framework for interacting Fermi gases beyond the ladder approximation. As an
application, we solve the equation of state for three- and two-dimensional
strongly interacting fermions and find excellent agreement with experimental
[Science 335, 563 (2012)] and other theoretical results above the temperature
0.5TF .


title: Fluctuation theorems and 1/f noise from a simple matrix

abstract:
  Here we present a model for a small system combined with an explicit entropy
bath that is comparably small. The dynamics of the model is defined by a simple
matrix, M. Each row of M corresponds to a macrostate of the system, e.g. net
alignment, while the elements in the row represent microstates. The constant
number of elements in each row ensures constant entropy, which allows
reversible fluctuations, similar to information theory where a constant number
of bits allows reversible computations. Many elements in M come from the
microstates of the system, but many others come from the bath. Bypassing the
bath states yields fluctuations that exhibit standard white noise; whereas with
bath states the power spectral density varies as S(f)~1/f over a wide range of
frequencies, f. Thus, the explicit entropy bath is the mechanism of 1/f noise
in this model. Both forms of the model match Crooks' fluctuation theorem
exactly, indicating that the theorem applies not only to infinite reservoirs,
but also to finite-sized baths. The model is used to analyze measurements of
1/f-like noise from a sub-micron tunnel junction.