title: Anisotropy of partially self-absorbed jets and the jet of Cyg X-1

abstract:
  We study the angular dependence of the flux from partially synchrotron
self-absorbed conical jets (proposed by Blandford \& K{\"o}nigl). We consider
the jet viewed from either a side or close to on axis, and in the latter case,
either from the jet top or bottom. We derive analytical formulae for the flux
in each of these cases, and find the exact solution for an arbitrary angle
numerically. We find that the maximum of the emission occurs when the jet is
viewed from top on-axis, which is contrast to a previous result, which found
the maximum at some intermediate angle and null emission on-axis. We then
calculate the ratio of the jet-to-counterjet emission for this model, which
depends on the viewing angle and the index of power-law electrons.
  We apply our results to the black-hole binary Cyg X-1. Given the
jet-to-counterjet flux ratio of $\gtrsim$50 found observationally and the
current estimates of the inclination, we find the jet velocity to be $\gtrsim
0.8c$. We also point out that when the projection effect is taken into account,
the radio observations imply the jet half-opening angle of $\lesssim 1^{\rm
o}$, a half of the value given before. When combined with the existing
estimates of $\Gamma_{\rm j}$, the jet half-opening angle is low, $\ll
1/\Gamma_{\rm j}$, and much lower than values observed in blazars, unless
$\Gamma_{\rm j}$ is much higher than currently estimated.


title: Gr\"obner coherent rings and modules

abstract:
  Let $R$ be a graded ring. We introduce a class of graded $R$-modules called
Gr\"obner-coherent modules. Roughly, these are graded $R$-modules that are
coherent as ungraded modules because they admit an adequate theory of Gr\"obner
bases. The class of Gr\"obner-coherent modules is formally similar to the class
of coherent modules: for instance, it is an abelian category closed under
extension. However, Gr\"obner-coherent modules come with tools for effective
computation that are not present for coherent modules.


title: Quantum-like models cannot account for the conjunction fallacy

abstract:
  Human agents happen to judge that a conjunction of two terms is more probable
than one of the terms, in contradiction with the rules of classical
probabilities---this is the conjunction fallacy. One of the most discussed
accounts of this fallacy is currently the quantum-like explanation, which
relies on models exploiting the mathematics of quantum mechanics. The aim of
this paper is to investigate the empirical adequacy of major quantum-like
models which represent beliefs with quantum states. We first argue that they
can be tested in three different ways, in a question order effect configuration
which is different from the traditional conjunction fallacy experiment. We then
carry out our proposed experiment, with varied methodologies from experimental
economics. The experimental results we get are at odds with the predictions of
the quantum-like models. This strongly suggests that this quantum-like account
of the conjunction fallacy fails. Future possible research paths are discussed.


title: The module theory of divided power algebras

abstract:
  We study modules for the divided power algebra $D$ in a single variable over
a commutative noetherian ring $k$. Our first result states that $D$ is a
coherent ring. In fact, we show that there is a theory of Gr\"obner bases for
finitely generated ideals, and so computations with finitely presented
$D$-modules are in principle algorithmic. We go on to determine much about the
structure of finitely presented $D$-modules, such as: existence of certain nice
resolutions, computation of the Grothendieck group, results about injective
dimension, and how they interact with torsion modules. Our results apply not
just to the classical divided power algebra, but to its $q$-variant as well,
and even to a much broader class of algebras we introduce called "generalized
divided power algebras." On the other hand, we show that the divided power
algebra in two variables over $\mathbf{Z}_p$ is not coherent.


title:
Scan Order in Gibbs Sampling: Models in Which it Matters and Bounds on
  How Much

abstract:
  Gibbs sampling is a Markov Chain Monte Carlo sampling technique that
iteratively samples variables from their conditional distributions. There are
two common scan orders for the variables: random scan and systematic scan. Due
to the benefits of locality in hardware, systematic scan is commonly used, even
though most statistical guarantees are only for random scan. While it has been
conjectured that the mixing times of random scan and systematic scan do not
differ by more than a logarithmic factor, we show by counterexample that this
is not the case, and we prove that that the mixing times do not differ by more
than a polynomial factor under mild conditions. To prove these relative bounds,
we introduce a method of augmenting the state space to study systematic scan
using conductance.


title:
Calculating the Middle Ages? The Project "Complexities and Networks in
  the Medieval Mediterranean and Near East" (COMMED)

abstract:
  The project "Complexities and networks in the Medieval Mediterranean and Near
East" (COMMED) at the Division for Byzantine Research of the Institute for
Medieval Research (IMAFO) of the Austrian Academy of Sciences focuses on the
adaptation and development of concepts and tools of network theory and
complexity sciences for the analysis of societies, polities and regions in the
medieval world in a comparative perspective. Key elements of its methodological
and technological toolkit are applied, for instance, in the new project
"Mapping medieval conflicts: a digital approach towards political dynamics in
the pre-modern period" (MEDCON), which analyses political networks and conflict
among power elites across medieval Europe with five case studies from the 12th
to 15th century. For one of these case studies on 14th century Byzantium, the
explanatory value of this approach is presented in greater detail. The
presented results are integrated in a wider comparison of five late medieval
polities across Afro-Eurasia (Byzantium, China, England, Hungary and Mamluk
Egypt) against the background of the {\guillemotright}Late Medieval
Crisis{\guillemotleft} and its political and environmental turmoil. Finally,
further perspectives of COMMED are outlined.


title:
Impact of holding umbrella on uni- and bi-directional pedestrian flow:
  Experiments and modeling

abstract:
  In this paper, the impact of holding umbrella on the uni- and bi-directional
flow has been investigated via experiment and modeling. In the experiments,
pedestrians are required to walk clockwise/anti-clockwise in a ring-shaped
corridor under normal situation and holding umbrella situation. No matter in
uni- or bi-directional flow, the flow rate under holding umbrella situation
decreases comparing with that in normal situation. In bidirectional flow,
pedestrians segregate into two opposite moving streams very quickly under
normal situation, and clockwise/anti-clockwise walking pedestrians are always
in the inner/outer lane due to right-walking preference. Under holding umbrella
situation, spontaneous lane formation has also occurred. However, when holding
umbrella, pedestrians may separate into more than two lanes. Moreover, the
merge of lanes have been observed, and clockwise/anti-clockwise pedestrians are
not always in the inner/outer lane. To model the flow dynamics, an improved
force-based model has been proposed. The contact force between umbrellas has
been taken into account. Simulation results are in agreement with the
experimental ones.


title:
Optimal Weights For Measuring Redshift Space Distortions in Multi-tracer
  Galaxy Catalogues

abstract:
  Since the volume accessible to galaxy surveys is fundamentally limited, it is
extremely important to analyse available data in the most optimal fashion. One
way of enhancing the cosmological information extracted from the clustering of
galaxies is by weighting the galaxy field. The most widely used weighting
schemes assign weights to galaxies based on the average local density in the
region (FKP weights) and their bias with respect to the dark matter field (PVP
weights). They are designed to minimize the fractional variance of the galaxy
power-spectrum. We demonstrate that the currently used bias dependent weighting
scheme can be further optimized for specific cosmological parameters. We
develop a procedure for computing the optimal weights and test them against
mock catalogues for which the values of all fitting parameters, as well as the
input power-spectrum are known. We show that by applying these weights to the
joint power-spectrum of Emission Line Galaxies and Luminous Red Galaxies from
the Dark Energy Spectroscopic Instrument survey, the variance in the measured
growth rate parameter can be reduced by as much as 36 per cent.


title:
Adiabatic hydrodynamic modes in dielectric environment in a random
  electric field

abstract:
  Dielectric is considered in the electric field that has equal to zero the
first moment and different from zero the second moment of strength in an
equilibrium. The equations of ideal hydrodynamics are obtained in such a field
for the case of the neglect of dissipative effects. A new variable - the second
moment of electric field strength is included in the Euler equation. A temporal
equation for this variable is obtained on the basis of Maxwell equations in the
hydrodynamic approximation. Adiabatic one-dimensional waves of small amplitude
are studied in this system. Proceeding from the theoretical estimation of the
intracrystalline field in an ionic crystal the good consent of the obtained
numerical values of transversal velocity of this wave with transversal velocity
of sound for isotropic crystals of alkali halides is found.


title:
Guaranteed Cost Approach to Robust Model Predictive Control of Uncertain
  Linear Systems

abstract:
  In this paper we propose a constrained guaranteed cost robust model
predictive controller (GCMPC) for uncertain discrete time systems. This
controller was developed based on a quadratic cost functional and guarantee
robustness with respect to quadratically bound uncertainties. Such a class of
problems is currently intractable by Min-Max Robust Model Predictive
Controllers without polytopic approximations of the uncertainties. The proposed
technique is computationally more efficient then an enumeration-based approach
and requires only a Quadratically Constrained Quadratic Problem (QCQP)
optimization, whereas LMI-based GCMPC approaches require a Semi-Definite
Programming (SDP) optimization.


title: An Investigation of AdS$_2$ Backreaction and Holography

abstract:
  We investigate a dilaton gravity model in AdS$_2$ proposed by Almheiri and
Polchinski and develop a 1d effective description in terms of a dynamical
boundary time with a Schwarzian derivative action. We show that the effective
model is equivalent to a 1d version of Liouville theory, and investigate its
dynamics and symmetries via a standard canonical framework. We include the
coupling to arbitrary conformal matter and analyze the effective action in the
presence of possible sources. We compute commutators of local operators at
large time separation, and match the result with the time shift due to a
gravitational shockwave interaction. We study a black hole evaporation process
and comment on the role of entropy in this model.


title: Deep Directed Generative Models with Energy-Based Probability Estimation

abstract:
  Training energy-based probabilistic models is confronted with apparently
intractable sums, whose Monte Carlo estimation requires sampling from the
estimated probability distribution in the inner loop of training. This can be
approximately achieved by Markov chain Monte Carlo methods, but may still face
a formidable obstacle that is the difficulty of mixing between modes with sharp
concentrations of probability. Whereas an MCMC process is usually derived from
a given energy function based on mathematical considerations and requires an
arbitrarily long time to obtain good and varied samples, we propose to train a
deep directed generative model (not a Markov chain) so that its sampling
distribution approximately matches the energy function that is being trained.
Inspired by generative adversarial networks, the proposed framework involves
training of two models that represent dual views of the estimated probability
distribution: the energy function (mapping an input configuration to a scalar
energy value) and the generator (mapping a noise vector to a generated
configuration), both represented by deep neural networks.


title: On Generalized Minors and Quiver Representations

abstract:
  The cluster algebra of any acyclic quiver can be realized as the coordinate
ring of a subvariety of a Kac-Moody group -- the quiver is an orientation of
its Dynkin diagram, defining a Coxeter element and thereby a double Bruhat
cell. We use this realization to connect representations of the quiver with
those of the group. We show that cluster variables of preprojective (resp.
postinjective) quiver representations are realized by generalized minors of
highest-weight (resp. lowest-weight) group representations, generalizing
results of Yang-Zelevinsky in finite type. In type $A_n^{\!(1)}$ and finitely
many other affine types, we show that cluster variables of regular quiver
representations are realized by generalized minors of group representations
that are neither highest- nor lowest-weight; we conjecture this holds more
generally.


title:
Everywhere divergence of the one-sided ergodic Hilbert transform and
  Liouville numbers

abstract:
  We prove some results on the behavior of infinite sums of the form $\Sigma
f\circ T^n(x)\frac{1}{n}$, where $T:S^1\to S^1$ is an irrational circle
rotation and $f$ is a mean-zero function on $S^1$. In particular, we show that
for a certain class of functions $f$, there are Liouville $\alpha$ for which
this sum diverges everywhere. We also show that there are Liouville $\alpha$
for which the sum converges everywhere.


title: Strongly regular graphs with the same parameters as the symplectic graph

abstract:
  We consider orbit partitions of groups of automorphisms for the symplectic
graph and apply Godsil-McKay switching. As a result, we find four families of
strongly regular graphs with the same parameters as the symplectic graphs,
including the one discovered by Abiad and Haemers. Also, we prove that switched
graphs are non-isomorphic to each other by considering the number of common
neighbors of three vertices.


title: Corrected quantum walk for optimal Hamiltonian simulation

abstract:
  We describe a method to simulate Hamiltonian evolution on a quantum computer
by repeatedly using a superposition of steps of a quantum walk, then applying a
correction to the weightings for the numbers of steps of the quantum walk. This
correction enables us to obtain complexity which is the same as the lower bound
up to double-logarithmic factors for all parameter regimes. The scaling of the
query complexity is $O\left( \tau \frac{\log\log\tau}{\log\log\log\tau} +
\log(1/\epsilon) \right)$ where $\tau := t\|H\|_{\max}d$, for $\epsilon$ the
allowable error, $t$ the time, $\|H\|_{\max}$ the max-norm of the Hamiltonian,
and $d$ the sparseness. This technique should also be useful for improving the
scaling of the Taylor series approach to simulation, which is relevant to
applications such as quantum chemistry.


title:
Equilibration Dynamics of Strongly Interacting Bosons in 2D Lattices
  with Disorder

abstract:
  Motivated by recent optical lattice experiments [J.-y. Choi et al., Science
352, 1547 (2016)], we study the dynamics of strongly interacting bosons in the
presence of disorder in two dimensions. We show that Gutzwiller mean-field
theory (GMFT) captures the main experimental observations, which are a result
of the competition between disorder and interactions. Our findings highlight
the difficulty in distinguishing glassy dynamics, which can be captured by
GMFT, and many-body localization, which cannot be captured by GMFT, and
indicate the need for further experimental studies of this system.


title: Broadband Neutron Interferometer

abstract:
  We demonstrate a two phase-grating, multi-beam neutron interferometer by
using a modified Ronchi setup in a far-field regime. The functionality of the
interferometer is based on the universal \moire effect that was recently
implemented for X-ray phase-contrast imaging in the far-field regime.
Interference fringes were achieved with monochromatic, bichromatic, and
polychromatic neutron beams; for both continuous and pulsed beams. This
far-field neutron interferometry allows for the utilization of the full neutron
flux for precise measurements of potential gradients, and expands neutron
phase-contrast imaging techniques to more intense polycromatic neutron beams.

categories: physics.ins-det nucl-ex physics.optics quant-ph


title: A Global Astrometric Solution for Pan-STARRS referenced to ICRF2

abstract:
  We describe development and application of a Global Astrometric Solution
(GAS) to the problem of Pan-STARRS1 (PS1) astrometry. Current PS1 astrometry is
based on differential astrometric measurements using 2MASS reference stars,
thus PS1 astrometry inherits the errors of the 2MASS catalog. The GAS, based on
a single, least squares adjustment to approximately 750k grid stars using over
3000 extragalactic objects as reference objects, avoids this catalog-to-catalog
propagation of errors to a great extent. The GAS uses a relatively small number
of Quasi-Stellar Objects (QSOs, or distant AGN) with very accurate (<1 mas)
radio positions, referenced to the ICRF2. These QSOs provide a hard constraint
in the global least squares adjustment. Solving such a system provides absolute
astrometry for all the stars simultaneously. The concept is much cleaner than
conventional astrometry but is not easy to perform for large catalogs. In this
paper we describe our method and its application to Pan-STARRS1 data. We show
that large-scale systematic errors are easily corrected but our solution
residuals for position (~60 mas) are still larger than expected based on
simulations (~10 mas). We provide a likely explanation for the reason the
small-scale residual errors are not corrected in our solution as would be
expected.


title: On Pfaffian and determinant of one type of skew centrosymmetric matrices

abstract:
  This paper is dedicated to compute Pfaffian and determinant of one type of
skew centrosymmetric matrices in terms of general number sequence of second
order.


title: Improving the RPC rate capability

abstract:
  This paper has the purpose to study the rate capability of the Resistive
Plate Chamber, RPC, starting from the basic physics of this detector. The
effect of different working parameters determining the rate capability is
analysed in detail, in order to optimize a new family of RPCs for applications
to heavy irradiation environments and in particular to the LHC phase 2. A
special emphasis is given to the improvement achievable by minimizing the
avalanche charge delivered in the gas. The paper shows experimental results of
Cosmic Ray tests, performed to study the avalanche features for different gas
gap sizes, with particular attention to the overall delivered charge. For this
purpose, the paper studies, in parallel to the prompt electronic signal, also
the ionic signal which gives the main contribution to the delivered charge.
Whenever possible the test results are interpreted on the base of the RPC
detector physics and are intended to extend and reinforce our physical
understanding of this detector.


title: Resurrecting the Dead Cone

abstract:
  The dead cone is a well-known effect in gauge theories, where radiation from
a charged particle of mass m and energy E is suppressed within an angular size
of m/E. This effect is universal as it does not depend on the spin of the
particle nor on the nature of the gauge interaction. It is challenging to
directly measure the dead cone at colliders, however, since the region of
suppressed radiation either is too small to be resolved or is filled by the
decay products of the massive particle. In this paper, we propose to use jet
substructure techniques to expose the dead cone effect in the strong-force
radiation pattern around boosted top quarks at the Large Hadron Collider. Our
study shows that with 300/fb of 13-14 TeV collision data, ATLAS and CMS could
obtain the first direct evidence of the dead cone effect and test its basic
features.


title: Pulsar Candidates Toward Fermi Unassociated Sources

abstract:
  We report on a search for steep spectrum radio sources within the 95%
confidence error ellipses of the Fermi unassociated sources from the Large
Array Telescope (LAT). Using existing catalogs and the newly released GMRT
all-sky survey at 150 MHz we identify compact radio sources that are bright at
MHz frequencies but faint or absent at GHz frequencies. Such steep spectrum
radio sources are rare and constitute a sample of pulsar candidates, selected
independently of period, dispersion measure, interstellar scattering and
orbital parameters. We find point-like, steep spectrum candidates toward 11
Fermi sources. Based on the gamma-ray/radio positional coincidence, the rarity
of such radio sources, and the properties of the 3FGL sources themselves, we
argue that many of these sources could be pulsars. They may have been missed by
previous radio periodicity searches due to interstellar propagation effects or
because they lie in an unusually tight binary. If this hypothesis is correct,
then renewed gamma-ray and radio periodicity searches at the positions of the
steep spectrum radio sources may reveal pulsations.


title:
SKA Weak Lensing III: Added Value of Multi-Wavelength Synergies for the
  Mitigation of Systematics

abstract:
  In this third paper of a series on radio weak lensing for cosmology with the
Square Kilometre Array, we scrutinise synergies between cosmic shear
measurements in the radio and optical/near-IR bands for mitigating systematic
effects. We focus on three main classes of systematics: (i) experimental
systematic errors in the observed shear; (ii) signal contamination by intrinsic
alignments; and (iii) systematic effects due to an incorrect modelling of
non-linear scales. First, we show that a comprehensive, multi-wavelength
analysis provides a self-calibration method for experimental systematic
effects, only implying <50% increment on the errors on cosmological parameters.
We also illustrate how the cross-correlation between radio and optical/near-IR
surveys alone is able to remove residual systematics with variance as large as
0.00001, i.e. the same order of magnitude of the cosmological signal. This also
opens the possibility of using such a cross-correlation as a means to detect
unknown experimental systematics. Secondly, we demonstrate that, thanks to
polarisation information, radio weak lensing surveys will be able to mitigate
contamination by intrinsic alignments, in a way similar but fully complementary
to available self-calibration methods based on position-shear correlations.
Lastly, we illustrate how radio weak lensing experiments, reaching higher
redshifts than those accessible to optical surveys, will probe dark energy and
the growth of cosmic structures in regimes less contaminated by non-linearities
in the matter perturbations. For instance, the higher-redshift bins of radio
catalogues peak at z~0.8-1, whereas their optical/near-IR counterparts are
limited to z<0.5-0.7. This translates into having a cosmological signal 2 to 5
times less contaminated by non-linear perturbations.


title:
The Connection Between Reddening, Gas Covering Fraction, and the Escape
  of Ionizing Radiation at High Redshift

abstract:
  We use a large sample of galaxies at z~3 to establish a relationship between
reddening, neutral gas covering fraction (fcov(HI)), and the escape of ionizing
photons at high redshift. Our sample includes 933 galaxies at z~3, 121 of which
have very deep spectroscopic observations (>7 hrs) in the rest-UV
(lambda=850-1300 A) with Keck/LRIS. Based on the high covering fraction of
outflowing optically-thick HI indicated by the composite spectra of these
galaxies, we conclude that photoelectric absorption, rather than dust
attenuation, dominates the depletion of ionizing photons. By modeling the
composite spectra as the combination of an unattenuated stellar spectrum
including nebular continuum emission with one that is absorbed by HI and
reddened by a line-of-sight extinction, we derive an empirical relationship
between E(B-V) and fcov(HI). Galaxies with redder UV continua have larger
covering fractions of HI characterized by higher line-of-sight extinctions. Our
results are consistent with the escape of Lya through gas-free lines-of-sight.
Covering fractions based on low-ionization interstellar absorption lines
systematically underpredict those deduced from the HI lines, suggesting that
much of the outflowing gas may be metal-poor. We develop a model which connects
the ionizing escape fraction with E(B-V), and which may be used to estimate the
escape fraction for an ensemble of high-redshift galaxies. Alternatively,
direct measurements of the escape fraction for our data allow us to constrain
the intrinsic 900-to-1500 A flux density ratio to be >0.20, a value that favors
stellar population models that include weaker stellar winds, a flatter initial
mass function, and/or binary evolution. Lastly, we demonstrate how the
framework discussed here may be used to assess the pathways by which ionizing
radiation escapes from high-redshift galaxies. [Abridged]


title:
Jet production in the CoLoRFulNNLO method: event shapes in
  electron-positron collisions

abstract:
  We present the CoLoRFulNNLO method to compute higher order radiative
corrections to jet cross sections in perturbative QCD. We apply our method to
the computation of event shape observables in electron-positron collisions at
NNLO accuracy and validate our code by comparing our predictions to previous
results in the literature. We also calculate for the first time jet cone energy
fraction at NNLO.


title: Unveiling the role of galactic rotation on star formation

abstract:
  We study the star formation process at galactic scales and the role of
rotation through numerical simulations of spiral and starburst galaxies using
the adaptive mesh refinement code Enzo. We focus on the study of three
integrated star formation laws found in the literature: the Kennicutt-Schmidt
(KS) and Silk-Elmegreen (SE) laws, and the dimensionally homogeneous equation
proposed by Escala (2015) $\Sigma_{\rm SFR} \propto \sqrt{G/L}\Sigma_{\rm
gas}^{1.5}$. We show that using the last we take into account the effects of
the integration along the line of sight and find a unique regime of star
formation for both types of galaxies, suppressing the observed bi-modality of
the KS law. We find that the efficiencies displayed by our simulations are
anti-correlated with the angular velocity of the disk $\Omega$ for the three
laws studied in this work. Finally, we show that the dimensionless efficiency
of star formation is well represented by an exponentially decreasing function
of $-1.9\Omega t_{\rm ff}^{\rm ini}$, where $t_{\rm ff}^{\rm ini}$ is the
initial free-fall time. This leads to a unique galactic star formation relation
which reduces the scatter of the bi-modal KS, SE, and Escala (2015) relations
by 43%, 43%, and 35% respectively.


title: Reality of Superstring Field Theory Action

abstract:
  We determine the reality conditions on the string fields that make the action
for heterotic and type II string field theories real.


title: Type-II Dirac surface states in topological crystalline insulators

abstract:
  We study the properties of a family of anti-pervoskite materials, which are
topological crystalline insulators with an insulating bulk but a conducting
surface. Using ab-initio DFT calculations, we investigate the bulk and surface
topology and show that these materials exhibit type-I as well as type-II Dirac
surface states protected by reflection symmetry. While type-I Dirac states give
rise to closed circular Fermi surfaces, type-II Dirac surface states are
characterized by open electron and hole pockets that touch each other. We find
that the type-II Dirac states exhibit characteristic van-Hove singularities in
their dispersion, which can serve as an experimental fingerprint. In addition,
we study the response of the surface states to magnetic fields.


title:
Nonlinear conductivity and the ringdown of currents in metallic
  holography

abstract:
  We study the electric and heat current response resulting from an electric
field quench in a holographic model of momentum relaxation at nonzero charge
density. After turning the electric field off, currents return to equilibrium
as governed by the vector quasi-normal modes of the dual black brane, whose
spectrum depends qualitatively on a parameter controlling the strength of
inhomogeneity. We explore the dynamical phase diagram as a function of this
parameter, showing that signatures of incoherent transport become identifiable
as an oscillatory ringdown of the heat current. We also study nonlinear
conductivity by holding the electric field constant. For small electric fields
a balance is reached between the driving electric field and the momentum sink
-- a steady state described by DC linear response. For large electric fields
Joule heating becomes important and the black branes exhibit significant time
dependence. In a regime where the rate of temperature increase is small, the
nonlinear electrical conductivity is well approximated by the DC linear
response calculation at an appropriate effective temperature.


title:
Self-induced glassiness and pattern formation in spin systems subject to
  long-range interactions

abstract:
  We study the glass formation in two- and three-dimensional Ising and
Heisenberg spin systems subject to competing interactions and uniaxial
anisotropy with a mean-field approach. In three dimensions, for sufficiently
strong anisotropy the systems always modulates in a striped phase. Below a
critical strength of the anisotropy, a glassy phase exists in a finite range of
temperature, and it becomes more stable as the system becomes more isotropic.
In two dimension the criticality is always avoided and the glassy phase always
exists.


title: Non-adiabatic bulk-surface oscillations in driven topological insulators

abstract:
  Recent theoretical and experimental work has suggested the tantalizing
possibility of opening a topological gap upon driving the surface states of a
three-dimensional strong topological insulator (TI) with circularly polarized
light. With this motivation, we study the response of TIs to a driving field
that couples to states near the surface. We unexpectedly find coherent
oscillations between the surface and the bulk and trace their appearance to
unavoidable resonances caused by photon absorption from the drive. We show how
these resonant oscillations may be captured by the Demkov- Osherov model of
multi-level Landau-Zener physics, leading to non-trivial consequences such as
the loss of adiabaticity upon slow ramping of the amplitude. We numerically
demonstrate that these oscillations are observable in the time-dependent Wigner
distribution, which is directly measurable in time-resolved ARPES experiments.
Our results apply generically to any system with surface states in the presence
of a gapped bulk, and thus suggest experimental signatures of a novel
surface-bulk coupling mechanism that is fundamental for proposals to engineer
non-trivial states by periodic driving.


title:
Using ForeCAT Deflections and Rotations to Constrain the Early Evolution
  of CMEs

abstract:
  To accurately predict the space weather effects of coronal mass ejection
(CME) impacts at Earth one must know if and when a CME will impact Earth, and
the CME parameters upon impact. Kay et al. (2015b) presents Forecasting a CME's
Altered Trajectory (ForeCAT), a model for CME deflections based on the magnetic
forces from the background solar magnetic field. Knowing the deflection and
rotation of a CME enables prediction of Earth impacts, and the CME orientation
upon impact. We first reconstruct the positions of the 2008 April 10 and the
2012 July 12 CMEs from the observations. The first of these CMEs exhibits
significant deflection and rotation (34 degrees deflection and 58 degrees
rotation), while the second shows almost no deflection or rotation (<3 degrees
each). Using ForeCAT, we explore a range of initial parameters, such as the CME
location and size, and find parameters that can successfully reproduce the
behavior for each CME. Additionally, since the deflection depends strongly on
the behavior of a CME in the low corona (Kay et al. (2015a, 2015b)), we are
able to constrain the expansion and propagation of these CMEs in the low
corona.


title:
A Dyadic Gehring Inequality in Spaces of Homogeneous Type and
  Applications

abstract:
  We state a version of Gehring's self improvement Theorem for reverse \Holder
weights which is valid for dyadic cubes over spaces of homogeneous type and
explore some of the consequences and applications.


title:
Topological order, symmetry, and Hall response of two-dimensional
  spin-singlet superconductors

abstract:
  Fully gapped two-dimensional superconductors coupled to dynamical
electromagnetism are known to exhibit topological order. In this work, we
develop a unified low-energy description for spin-singlet paired states by
deriving topological Chern-Simons field theories for $s$-wave, $d+id$, and
chiral higher even-wave superconductors. These theories capture the quantum
statistics and fusion rules of Bogoliubov quasiparticles and vortices and
incorporate global continuous symmetries - specifically, spin rotation and
conservation of magnetic flux - present in all singlet superconductors. For all
such systems, we compute the Hall response for these symmetries and investigate
the physics at the edge. In particular, the weakly-coupled phase of a chiral
$d+id$ chiral state has a spin Hall coefficient $\nu_s=2$ and a vanishing Hall
response for the magnetic flux symmetry. We argue that the latter is a generic
result for two-dimensional superconductors with gapped photons, thereby
demonstrating the absence of a spontaneous magnetic field in the ground state
of chiral superconductors. It is also shown that the Chern-Simons theories of
chiral spin-singlet superconductors derived here fall into Kitaev's 16-fold
classification of topological superconductors.

categories: cond-mat.supr-con cond-mat.mes-hall cond-mat.str-el hep-th


title: Opportunistic Scheduling over Renewal Systems: An Empirical Method

abstract:
  This paper considers an opportunistic scheduling problem over a renewal
system. A controller observes a random event at the beginning of each renewal
frame and then chooses an action in response to the event, which affects the
duration of the frame, the amount of resources used, and a penalty metric. The
goal is to make frame-wise decisions so as to minimize the time average penalty
subject to time average resource constraints. This problem has applications to
task processing and communication in data networks, as well as to certain
classes of Markov decision problems. We formulate the problem as a dynamic
fractional program and propose an adaptive algorithm which uses an empirical
accumulation as a feedback parameter. A key feature of the proposed algorithm
is that it does not require knowledge of the random event statistics and
potentially allows (uncountably) infinite event sets. We prove the algorithm
satisfies all desired constraints and achieves $O(\epsilon)$ near optimality
with probability 1.


title: ROTSE1 J164341.65+251748.1: a new W UMa-type eclipsing binary

abstract:
  ROTSE1 J164341.65+251748.1 was photometrically observed in the V band during
three epochs with the 0.84-m telescope of the San Pedro M\'artir Observatory in
Mexico. Based on additional BVR photometry, we find that the primary star has a
spectral type around G0V. The light curve of the system is typical of a W~UMa
type binary stars and has an orbital period of $\sim$ 0.323 days. In an effort
to gain a better understanding of the binary system and determine its physical
properties, we analyzed the light curve with the Wilson and Devinney method. We
found that ROTSE1 J164341.65+251748.1 has a mass ratio of $\sim$ 0.34 and that
the less massive component is over 230 K hotter than the primary star. The
inclination of the system is $\sim$ 84.6 degrees, and the {\bf degree} of
over-contact is 11\%. The analysis shows the presence of variable bright spots
on the primary star.


title:
Tunneling into quantum wires: regularization of the tunneling
  Hamiltonian and consistency between free and bosonized fermions

abstract:
  Tunneling between a point contact and a one-dimensional wire is usually
described with the help of a tunneling Hamiltonian that contains a delta
function in position space. Whereas the leading order contribution to the
tunneling current is independent of the way this delta function is regularized,
higher-order corrections with respect to the tunneling amplitude are known to
depend on the regularization. Instead of regularizing the delta function in the
tunneling Hamiltonian, one may also obtain a finite tunneling current by
invoking the ultraviolet cut-offs in a field-theoretic description of the
electrons in the one-dimensional conductor, a procedure that is often used in
the literature. For the latter case, we show that standard ultraviolet cut-offs
lead to different results for the tunneling current in fermionic and bosonized
formulations of the theory, when going beyond leading order in the tunneling
amplitude. We show how to recover the standard fermionic result using the
formalism of functional bosonization and revisit the tunneling current to
leading order in the interacting case.


title: Fermionic 6$j$-symbols in superfusion categories

abstract:
  We describe how the study of superfusion categories (roughly speaking, fusion
categories enriched over the category of super vector spaces) reduces to that
of fusion categories over sVect, in the sense of Drinfeld, Gelaki, Nikshych,
and Ostrik. Following Brundan and Ellis, we give the construction of the
underlying fusion category of a superfusion category, and give an explicit
formula for the associator in this category in terms of 6$j$-symbols. We give a
definition of the $\pi$-Grothendieck ring of a superfusion category, and prove
a version of Ocneanu rigidity for superfusion categories.


title:
Circular Motion of a Small Oscillator in a Zero-Point Field Without
  External Forces: Is It Possible?

abstract:
  A small dipole oscillator moving along a circular trajectory in zero-point
electromagnetic field ( ZPF ) and with a polarization normal to the rotation
plane, is considered. Temporal periodicity conditions are imposed on ZPF,
associated with the way the rotating oscillator observes ZPF. They are similar
to spatial boundary conditions in Casimir phenomenon and therefore result in
ZPF spectrum change from continuous one to a discrete one and, as a
consequence, an effective temperature of the modified ZPF (Y. S. Levin ). The
average centripetal average force on the oscillator, originating from this
modified ZPF scattered by the oscillator in the near zone, is calculated in
terms of the bilinear correlation functions of electromagnetic field. After
renormalization of the correlation function, which physically means extraction
of a pure effect of periodicity, the force has a finite value. All calculations
are carried out using the methodology of stochastic electrodynamics. The radial
component of the force is directed to the center of rotation. In non
relativistic case and for oscillator frequency smaller than rotation frequency,
the force turns out to be proportional to the rotation radius. Such result
could mean a possibility that micro motion of the oscillator in ZPF sustains
its average circular motion without any other external forces.Though the
estimation done for the point-like electron shows that the effect is not
observable because the radius of such circular electron motion would have been
much smaller than the classical electron radius when our semi classical
approach to the electromagnetic problem does not work. It is well expected
result and considered as the first step in the application of the idea in the
quark world governed by non abelian colored fields, subject of the next paper.


title: An improved bound on $(A+A)/(A+A)$

abstract:
  We show that, for a finite set $A$ of real numbers, the size of the set
$$\frac{A+A}{A+A} = \left\{ \frac{a+b}{c+d} : a,b,c,d \in A, c+d \neq 0 \right
\}$$ is bounded from below by $$\left|\frac{A+A}{A+A} \right| \gg
\frac{|A|^{2+1/4}}{|A / A|^{1/8} \log |A|}.$$ This improves a result of
Roche-Newton.


title:
Indirect Coupling between Two Cavity Photon Systems via Ferromagnetic
  Resonance

abstract:
  We experimentally realize indirect coupling between two cavity modes via
strong coupling with the ferromagnetic resonance in Yttrium Iron Garnet (YIG).
We find that some indirectly coupled modes of our system can have a higher
microwave transmission than the individual uncoupled modes. Using a coupled
harmonic oscillator model, the influence of the oscillation phase difference
between the two cavity modes on the nature of the indirect coupling is
revealed. These indirectly coupled microwave modes can be controlled using an
external magnetic field or by tuning the cavity height. This work has potential
for use in controllable optical devices and information processing
technologies.


title:
Linear perturbation theory for tidal streams and the small-scale CDM
  power spectrum

abstract:
  Tidal streams in the Milky Way are sensitive probes of the population of
dark-matter subhalos predicted in cold-dark-matter (CDM) simulations. We
present a new calculus for computing the effect of subhalo fly-bys on cold
tidal streams based on the action-angle representation of streams. The heart of
this calculus is a line-of-parallel-angle approach that calculates the
perturbed distribution function of a given stream segment by undoing the effect
of all impacts. This approach allows one to compute the perturbed stream
density and track in any coordinate system in minutes for realizations of the
subhalo distribution down to 10^5 Msun, accounting for the stream's internal
dispersion and overlapping impacts. We study the properties of density and
track fluctuations with suites of simulations. The one-dimensional density and
track power spectra along the stream trace the subhalo mass function, with
higher-mass subhalos producing power only on large scales, while lower mass
subhalos cause structure on smaller scales. The time-dependence of impacts and
of the evolution of the stream after an impact gives rise to bispectra. We
further find that tidal streams are essentially corrugated sheets in the
presence of subhalo perturbations: different projections of the track all
reflect the same pattern of perturbations, facilitating their observational
measurement. We apply this formalism to density data for the Pal 5 stream and
make a first rigorous determination of 10^{+11}_{-6} dark-matter subhalos with
masses between 3x10^6 and 10^9 Msun within 20 kpc from the Galactic center
(corresponding to 1.4^{+1.6}_{-0.9} times the number predicted by CDM-only
simulations or to f_{sub}(r<20 kpc) ~ 0.2%). Improved data will allow
measurements of the subhalo mass function down to 10^5 Msun, thus definitively
testing whether dark matter clumps on the smallest scales relevant for galaxy
formation.


title: Chip-scale cavity optomechanics in lithium niobate

abstract:
  We develop a chip-scale cavity optomechanical system in single-crystal
lithium niobate that exhibits high optical quality factors and a large
frequency-quality product as high as $3.6\times 10^{12}$ Hz at room temperature
and atmosphere. The excellent optical and mechanical properties together with
the strong optomechanical coupling allow us to efficiently excite the coherent
regenerative optomechanical oscillation operating at 375.8 MHz with a threshold
power of 174 ${\rm \mu W}$ in the air. The demonstrated lithium niobate
optomechanical device enables great potential for achieving
electro-optic-mechanical hybrid systems for broad applications in sensing,
metrology, and quantum physics.


title: Super-Resolution From Binary Measurements With Unknown Threshold

abstract:
  We address the problem of super-resolution of point sources from binary
measurements, where random projections of the blurred measurement of the actual
signal are encoded using only the sign information. The threshold used for
binary quantization is not known to the decoder. We develop an algorithm that
solves convex programs iteratively and achieves signal recovery. The proposed
algorithm, which we refer to as the binary super-resolution (BSR) algorithm,
recovers point sources with reasonable accuracy, albeit up to a scale factor.
We show through simulations that the BSR algorithm is successful in recovering
the locations and the amplitudes of the point sources, even in the presence of
significant amount of blurring. We also propose a framework for handling noisy
measurements and demonstrate that BSR gives a reliable reconstruction
(correspondingly, reconstruction signal-to-noise ratio (SNR) of about 22 dB)
for a measurement SNR of 15 dB.


title: Face Detection with the Faster R-CNN

abstract:
  The Faster R-CNN has recently demonstrated impressive results on various
object detection benchmarks. By training a Faster R-CNN model on the large
scale WIDER face dataset, we report state-of-the-art results on two widely used
face detection benchmarks, FDDB and the recently released IJB-A.


title: Learning overcomplete, low coherence dictionaries with linear inference

abstract:
  Finding overcomplete latent representations of data has applications in data
analysis, signal processing, machine learning, theoretical neuroscience and
many other fields. In an overcomplete representation, the number of latent
features exceeds the data dimensionality, which is useful when the data is
undersampled by the measurements (compressed sensing, information bottlenecks
in neural systems) or composed from multiple complete sets of linear features,
each spanning the data space. Independent Components Analysis (ICA) is a linear
technique for learning sparse latent representations, which typically has a
lower computational cost than sparse coding, its nonlinear, recurrent
counterpart. While well suited for finding complete representations, we show
that overcompleteness poses a challenge to existing ICA algorithms.
Specifically, the coherence control in existing ICA algorithms, necessary to
prevent the formation of duplicate dictionary features, is ill-suited in the
overcomplete case. We show that in this case several existing ICA algorithms
have undesirable global minima that maximize coherence. Further, by comparing
ICA algorithms on synthetic data and natural images to the computationally more
expensive sparse coding solution, we show that the coherence control biases the
exploration of the data manifold, sometimes yielding suboptimal solutions. We
provide a theoretical explanation of these failures and, based on the theory,
propose improved overcomplete ICA algorithms. All told, this study contributes
new insights into and methods for coherence control for linear ICA, some of
which are applicable to many other, potentially nonlinear, unsupervised
learning methods.


title: De-identification of Patient Notes with Recurrent Neural Networks

abstract:
  Objective: Patient notes in electronic health records (EHRs) may contain
critical information for medical investigations. However, the vast majority of
medical investigators can only access de-identified notes, in order to protect
the confidentiality of patients. In the United States, the Health Insurance
Portability and Accountability Act (HIPAA) defines 18 types of protected health
information (PHI) that needs to be removed to de-identify patient notes. Manual
de-identification is impractical given the size of EHR databases, the limited
number of researchers with access to the non-de-identified notes, and the
frequent mistakes of human annotators. A reliable automated de-identification
system would consequently be of high value.
  Materials and Methods: We introduce the first de-identification system based
on artificial neural networks (ANNs), which requires no handcrafted features or
rules, unlike existing systems. We compare the performance of the system with
state-of-the-art systems on two datasets: the i2b2 2014 de-identification
challenge dataset, which is the largest publicly available de-identification
dataset, and the MIMIC de-identification dataset, which we assembled and is
twice as large as the i2b2 2014 dataset.
  Results: Our ANN model outperforms the state-of-the-art systems. It yields an
F1-score of 97.85 on the i2b2 2014 dataset, with a recall 97.38 and a precision
of 97.32, and an F1-score of 99.23 on the MIMIC de-identification dataset, with
a recall 99.25 and a precision of 99.06.
  Conclusion: Our findings support the use of ANNs for de-identification of
patient notes, as they show better performance than previously published
systems while requiring no feature engineering.


title: Generative Adversarial Imitation Learning

abstract:
  Consider learning a policy from example expert behavior, without interaction
with the expert or access to reinforcement signal. One approach is to recover
the expert's cost function with inverse reinforcement learning, then extract a
policy from that cost function with reinforcement learning. This approach is
indirect and can be slow. We propose a new general framework for directly
extracting a policy from data, as if it were obtained by reinforcement learning
following inverse reinforcement learning. We show that a certain instantiation
of our framework draws an analogy between imitation learning and generative
adversarial networks, from which we derive a model-free imitation learning
algorithm that obtains significant performance gains over existing model-free
methods in imitating complex behaviors in large, high-dimensional environments.


title:
Constraints on lepton number violating short-range interactions from
  $|\Delta L|=2$ processes

abstract:
  In this work we study the short-range contributions that induce effective
lepton number violating (LNV) interactions. We obtain a full set of constraints
on the effective short-range couplings from a large variety of low-energy
$|\Delta L|= 2$ processes of pseudoscalar mesons $K, D, D_s, B$, and
$\tau$-lepton. These constraints provide complementary and additional
information to the one obtained from the neutrinoless double-$\beta$
($0\nu\beta\beta$) decay. As expected, the bounds on electron-electron
short-range couplings are the only ones that are strongly constrained by the
$0\nu\beta\beta$ decay. Although weaker, LNV effective couplings with different
flavours are not accessible to $0\nu\beta\beta$ decay and these can be probe by
the $|\Delta L|= 2$ processes in consideration.


title: Achieving metrological precision limits through post-selection

abstract:
  Post-selection strategies have been proposed with the aim of amplifying weak
signals, which may help to overcome detection thresholds associated with
technical noise in high-precision measurements. Here we use an optical setup to
experimentally explore two different post-selection protocols for the
estimation of a small parameter: a weak-value amplification procedure and an
alternative method, that does not provide amplification, but nonetheless is
shown to be more robust for the sake of parameter estimation. Each technique
leads approximately to the saturation of quantum limits for the estimation
precision, expressed by the Cram\'er-Rao bound. For both situations, we show
that information on the parameter is obtained jointly from the measuring device
and the post-selection statistics.


title: Ion Crystal Metamorphoses in a Paul trap

abstract:
  The standard second-order pseudo-oscillator potential used in many analytical
investigations of the properties of ions stored in a Paul trap has serious
limitations. In this paper we show that ion-crystal configurations exhibited by
2, 3, and 4 simultaneously stored ions in a Paul trap are not predicted by the
standard pseudo-oscillator potential, but are all captured qualitatively and
quantitatively by an extended pseudopotential derived in this paper. The power
of our extended pseudopotential extends in particular to the prediction of the
border lines between different crystal configurations (morphologies) in the
Paul trap's $a$, $q$ stability diagram. In the three- and four-ion cases,
several of the ion-crystal structures predicted by our improved pseudopotential
have never been observed experimentally before. We present them here as a
challenge for experiments.


title:
LANet: An Enriched Knowledgebase for Location-aware Activity
  Recommendation System

abstract:
  Accumulation of large amount of location-specific reviews on web due to
escalating popularity of Location-based Social Networking platforms like Yelp,
Foursquare, Brightkite etc. in recent years, has created the opportunity to
discover location-specific activities and develop myriads of location-aware
activity recommendation applications. The performance and popularity of such
recommendation applications greatly depend on the richness and accuracy of the
back-end knowledgebase, which intern is regulated by information relevancy and
redundancy issues. Existing work on activity discovery have not made any
attempt to ensure relevancy and non-redundancy of discovered knowledge (i.e.,
location-specific activities). Moreover, majority of these work have utilized
body-worn sensors, images or human GPS traces and discovered generalized
activities that do not convey any location-specific knowledge.
  In this thesis, we address the mentioned issues with serious concern and
propose an effective solution to discover Location-specific Activity Network,
in short LANet from location-aware reviews. The information network LANet
serves as an accurate, enriched and unified knowledgebase of a Location-aware
Activity Recommendation System. While building LANet, we also introduce novel
ideas like, activity-based location similarity detection and measuring
uniqueness, generality/speciality of an activity at a particular location to
enrich the said knowledge base to a great extent. Experimental results show the
information richness and accuracy of the proposed knowledge base which is
comparable to human perception and accounts for our success in achieving the
desired solution.


title:
$O(N)$ model in Euclidean de Sitter space: beyond the leading infrared
  approximation

abstract:
  We consider an $O(N)$ scalar field model with quartic interaction in
$d$-dimensional Euclidean de Sitter space. In order to avoid the problems of
the standard perturbative calculations for light and massless fields, we
generalize to the $O(N)$ theory a systematic method introduced previously for a
single field, which treats the zero modes exactly and the nonzero modes
perturbatively. We compute the two-point functions taking into account not only
the leading infrared contribution, coming from the self-interaction of the zero
modes, but also corrections due to the interaction of the ultraviolet modes.
For the model defined in the corresponding Lorentzian de Sitter spacetime, we
obtain the two-point functions by analytical continuation. We point out that a
partial resummation of the leading secular terms (which necessarily involves
nonzero modes) is required to obtain a decay at large distances for massless
fields. We implement this resummation along with a systematic double expansion
in an effective coupling constant $\sqrt\lambda$ and in 1/N. We explicitly
perform the calculation up to the next-to-next-to-leading order in
$\sqrt\lambda$ and up to next-to-leading order in 1/N. The results reduce to
those known in the leading infrared approximation. We also show that they
coincide with the ones obtained directly in Lorentzian de Sitter spacetime in
the large N limit, provided the same renormalization scheme is used.


title: Study of human accessibility: physical tests versus numerical simulation

abstract:
  Consideration of physical dimensions of the user population is essential to
design adapted environment. This variability in body dimensions (called
"anthropometry") is involved in design tools commonly used today to assess
user's accommodation (physical mock-ups, population models, database, boundary
manikins, hybrid methods or digital human modeling). Databases are created from
campaigns of measurement. Besides the fact that such measures are costly in
time and money, they give more "static" measures of man. They do not take into
account possible stretching limbs that could allow increased accessibility.
This paper presents a methodology for human body modeling, in a dynamic way,
not static. The methodology allows to highlight influences of design and human
behaviour on reach skills, directly induced by the interaction with real
prototypes and not just considered by human physical dimensions. The first part
of the method is to create a database of measurements (arms length, hip
breadth, etc.). From these data, a model of accessibility is proposed. The
accessibility field is determined purely numerically. In parallel, an
experiment is set up to measure the extension of the accessibility field, with
the same people. A comparison of the results is then performed and a new model
of the human body is proposed.


title:
A Fast Algorithm for Finding Point Sources in the Fermi Data Stream:
  FermiFAST

abstract:
  We present a new and efficient algorithm for finding point sources in the
photon event data stream from the Fermi Gamma-Ray Space Telescope, FermiFAST.
The key advantage of FermiFAST is that it constructs a catalogue of potential
sources very fast by arranging the photon data in a hierarchical data
structure. Using this structure FermiFAST rapidly finds the photons that could
have originated from a potential gamma-ray source. It calculates a likehihood
ratio for the contribution of the potential source using the angular
distribution of the photons within the region of interest. It can find within a
few minutes the most significant half of the Fermi Third Point Source catalogue
(3FGL) with nearly 80\% purity from the four years of data used to construct
the catalogue. If a higher purity sample is desirable, one can achieve a sample
that includes the most significant third of the Fermi 3FGL with only five
percent of the sources unassociated with Fermi sources. Outside the galaxy
plane, all but eight of the 580 FermiFAST detections are associated with 3FGL
sources. And of these eight, six yield significant detections of greater than
five sigma when a further binned likelihood analysis is performed. This
software allows for rapid exploration of the Fermi data, simulation of the
source detection to calculate the selection function of various sources and the
errors in the obtained parameters of the sources detected.


title: VECSEL systems for generation and manipulation of trapped magnesium ions

abstract:
  Experiments in atomic, molecular, and optical (AMO) physics rely on lasers at
many different wavelengths and with varying requirements on spectral linewidth,
power, and intensity stability. Vertical external-cavity surface-emitting
lasers (VECSELs), when combined with nonlinear frequency conversion, can
potentially replace many of the laser systems currently in use. Here we present
and characterize VECSEL systems that can perform all laser-based tasks for
quantum information processing experiments with trapped magnesium ions. For
photoionization of neutral magnesium, 570.6$\,$nm light is generated with an
intracavity frequency-doubled VECSEL containing a lithium triborate (LBO)
crystal for second harmonic generation. External frequency doubling produces
285.3$\,$nm light for resonant interaction with the $^{1}S_{0}\leftrightarrow$
$^{1}P_{1}$ transition of neutral Mg. Using an externally frequency-quadrupled
VECSEL, we implement Doppler cooling of $^{25}$Mg$^{+}$ on the 279.6$\,$nm
$^{2}S_{1/2}\leftrightarrow$ $^{2}P_{3/2}$ cycling transition, repumping on the
280.4$\,$nm $^{2}S_{1/2}\leftrightarrow$ $^{2}P_{1/2}$ transition, coherent
state manipulation, and resolved sideband cooling close to the motional ground
state. Our systems serve as prototypes for applications in AMO requiring
single-frequency, power-scalable laser sources at multiple wavelengths.


title:
Landau-Level Mixing and Particle-Hole Symmetry Breaking for Spin
  Transitions in the Fractional Quantum Hall Effect

abstract:
  The spin transitions in the fractional quantum Hall effect provide a direct
measure of the tiny energy differences between differently spin-polarized
states, and thereby serve as an extremely sensitive test of the quantitative
accuracy of the theory of the fractional quantum Hall effect, and, in
particular, of the role of Landau-level mixing in lifting the particle-hole
symmetry. We report on an accurate quantitative study of this physics,
evaluating the effect of Landau-level mixing in a nonperturbative manner using
a fixed-phase diffusion Monte Carlo method. We find excellent agreement between
our calculated critical Zeeman energies and the experimentally measured values.
In particular, we find, as also do experiments, that the critical Zeeman
energies for fractional quantum Hall states at filling factors $\nu=2-n/(2n\pm
1)$ are significantly higher than those for $\nu=n/(2n\pm 1)$, a quantitative
signature of the lifting of particle-hole symmetry due to Landau-level mixing.


title:
The Radon Transform over Cones with Vertices on the Sphere and
  Orthogonal Axes

abstract:
  Recovering a function from its integrals over circular cones recently gained
significance because of its relevance to novel medical imaging technologies
such emission tomography using Compton cameras. In this paper we investigate
the case where the vertices of the cones of integration are restricted to a
sphere in $n$-dimensional space and symmetry axes are orthogonal to the sphere.
We show invertibility of the considered transform and develop an inversion
method based on series expansion and reduction to a system of one-dimensional
integral equations of generalized Abel type. Because the arising kernels do not
satisfy standard assumptions, we also develop a uniqueness result for
generalized Abel equations where the kernel has zeros on the diagonal. Finally,
we demonstrate how to numerically implement our inversion method and present
numerical results.


title: Magnetic properties of a Fermi gas in a noncommutative phase space

abstract:
  Motivated by the precision attained by SQUID devices in measuring magnetic
fields, we study in this article the thermodynamic behaviour of a fermion gas
in two and three dimen\-sional spatial space with noncommutative coordinates
and momenta. An explicit expression, both for Landau's diamagnetism and Pauli's
paramagnetism, is obtained for the magnetization and magnetic susceptibility of
the gas in two and three spatial dimensions. These results show that an upper
bound for the noncommutative parameter $\theta\lesssim (10 \,\text{Gev})^{-2}$
could be obtained.


title: A photonic platform for donor spin qubits in silicon

abstract:
  Donor impurity spins in silicon-28 are highly competitive qubits for upcoming
solid-state quantum technologies, yet a proven scalable strategy for
multi-qubit devices remains conspicuously absent. These CMOS-compatible,
atomically identical qubits offer significant advantages including 3-hour
coherence ($T_2$) lifetimes, as well as simultaneous qubit initialization,
manipulation and readout fidelities near $\sim\!99.9\%$. These properties meet
the requirements for many modern quantum error correction protocols, which are
essential for constructing large-scale universal quantum technologies. However,
a method of reliably coupling spatially-separated qubits, which crucially does
not sacrifice qubit quality and is robust to manufacturing imperfections, has
yet to be identified. Here we present such a platform for donor qubits in
silicon, by exploiting optically-accessible `deep' chalcogen donors. We show
that these donors emit highly uniform light, can be optically initialized, and
offer long-lived spin qubit ground states without requiring milliKelvin
temperatures. These combined properties make chalcogen donors uniquely suitable
for incorporation into silicon photonic architectures for single-shot
single-qubit readout as well as for multi-qubit coupling. This unlocks clear
pathways for silicon-based quantum computing, spin to photon conversion,
photonic memories, silicon-integrated triggered single photon sources and
all-optical silicon switches.


title:
Effect of Li Adsorption on the Electronic and Hydrogen Storage
  Properties of Acenes: A Dispersion-Corrected TAO-DFT Study

abstract:
  Due to the presence of strong static correlation effects and noncovalent
interactions, accurate prediction of the electronic and hydrogen storage
properties of Li-adsorbed acenes with n linearly fused benzene rings (n = 3 -
8) has been very challenging for conventional electronic structure methods. To
meet the challenge, we study these properties using our recently developed
thermally-assisted-occupation density functional theory (TAO-DFT) with
dispersion corrections. In contrast to pure acenes, the binding energies of H2
molecules on Li-adsorbed acenes are in the ideal binding energy range (about 20
to 40 kJ/mol per H2). Besides, the H2 gravimetric storage capacities of
Li-adsorbed acenes are in the range of 9.9 to 10.7 wt%, satisfying the United
States Department of Energy (USDOE) ultimate target of 7.5 wt%. On the basis of
our results, Li-adsorbed acenes can be high-capacity hydrogen storage materials
for reversible hydrogen uptake and release at ambient conditions.


title: The Mythos of Model Interpretability

abstract:
  Supervised machine learning models boast remarkable predictive capabilities.
But can you trust your model? Will it work in deployment? What else can it tell
you about the world? We want models to be not only good, but interpretable. And
yet the task of interpretation appears underspecified. Papers provide diverse
and sometimes non-overlapping motivations for interpretability, and offer
myriad notions of what attributes render models interpretable. Despite this
ambiguity, many papers proclaim interpretability axiomatically, absent further
explanation. In this paper, we seek to refine the discourse on
interpretability. First, we examine the motivations underlying interest in
interpretability, finding them to be diverse and occasionally discordant. Then,
we address model properties and techniques thought to confer interpretability,
identifying transparency to humans and post-hoc explanations as competing
notions. Throughout, we discuss the feasibility and desirability of different
notions, and question the oft-made assertions that linear models are
interpretable and that deep neural networks are not.


title: Luminescence engineering in plasmonic meta-surfaces

abstract:
  Photoluminescence is a phenomenon of significant interest due to its wide
range of technological applications in plasmonics, nanolasers, spasers, lasing
spasers, loss compensation and gain in metamaterials, and luminescent media.
Nanostructured materials are known to have very different luminescence
characteristics to bulk samples or planar films. Here we show that by
engineering a nanostructured meta-surface, we can choose the position of
photoluminescence absorption and emission lines of thin gold films. The
nanostructuring also aids to strong enhancement of the emission from gold, by a
factor of 76 in our experiments. This enhancement is determined by the relative
position of the engineered absorption and emission lines to the exciting laser
wavelength and the intrinsic properties of the constituent material. These
luminescence-engineered materials combined with a resonant material, as in the
lasing spaser, or with the power of reconfigurable metamaterials promise huge
potential as tunable nanoscale light sources.


title: On a radiative origin of the Standard Model from Trinification

abstract:
  In this work, we present a trinification-based grand unified theory
incorporating a global $\mathrm{SU}(3)$ family symmetry that after a
spontaneous breaking leads to a left-right symmetric model. Already at the
classical level, this model can accommodate the matter content and the quark
Cabbibo mixing in the Standard Model (SM) with only one Yukawa coupling at the
unification scale. Considering the minimal low-energy scenario with the least
amount of light states, we show that the resulting effective theory enables
dynamical breaking of its gauge group down to that of the SM by means of
radiative corrections accounted for by the renormalisation group evolution at
one loop. This result paves the way for a consistent explanation of the SM
breaking scale and fermion mass hierarchies.


title:
Cooperative Data Offload in Opportunistic Networks: From Mobile Devices
  to Infrastructure

abstract:
  Opportunistic mobile networks consisting of intermittently connected mobile
devices have been exploited for various applications, such as computational
offloading and mitigating cellular traffic load. In contrast to existing work,
in this paper, we focus on cooperatively offloading data among mobile devices
to maximally improve the probability of data delivery from a mobile device to
intermittently connected infrastructure within a given time constraint, which
is referred to as the \textit{cooperative offloading} problem. Unfortunately,
the estimation of data delivery probability over an opportunistic path is
difficult and cooperative offloading is NP-hard. To this end, we first propose
a probabilistic framework that provides the estimation of such probability.
Based on the proposed probabilistic framework, we design a heuristic algorithm
to solve cooperative offloading at a low computation cost. Due to the lack of
global information, a distributed algorithm is further proposed. The
performance of the proposed approaches is evaluated based on both synthetic
networks and real traces. Experimental results show that the probabilistic
framework can accurately estimate the data delivery probability, cooperative
offloading greatly improves the delivery probability, the heuristic algorithm
approximates the optimum, and the performance of both the heuristic algorithm
and distributed algorithm outperforms other approaches.


title:
Failure-recovery model with competition between failures in complex
  networks: a dynamical approach

abstract:
  Real systems are usually composed by units or nodes whose activity can be
interrupted and restored intermittently due to complex interactions not only
with the environment, but also with the same system. Majdand\v{z}i\'c $et\;al.$
[Nature Physics 10, 34 (2014)] proposed a model to study systems in which
active nodes fail and recover spontaneously in a complex network and found that
in the steady state the density of active nodes can exhibit an abrupt
transition and hysteresis depending on the values of the parameters. Here we
investigate a model of recovery-failure from a dynamical point of view. Using
an effective degree approach we find that the systems can exhibit a temporal
sharp decrease in the fraction of active nodes. Moreover we show that,
depending on the values of the parameters, the fraction of active nodes has an
oscillatory regime which we explain as a competition between different failure
processes. We also find that in the non-oscillatory regime, the critical
fraction of active nodes presents a discontinuous drop which can be related to
a "targeted" k-core percolation process. Finally, using mean field equations we
analyze the space of parameters at which hysteresis and oscillatory regimes can
be found.


title: On exponential sums over orbits in $\mathbb{F}_p^d$

abstract:
  This paper proves a bound for exponential sums over orbits of vectors in
$\mathbb{F}_p^d$ under subgroups of $\rm{GL}_d(\mathbb{F}_p)$. The main tool is
a classification theorem for approximate groups due to Gill, Helfgott, Pyber,
and Szab\'o.


title:
A Critical Value Function Approach, with an Application to Persistent
  Time-Series

abstract:
  Researchers often rely on the t-statistic to make inference on parameters in
statistical models. It is common practice to obtain critical values by
simulation techniques. This paper proposes a novel numerical method to obtain
an approximately similar test. This test rejects the null hypothesis when the
test statistic is larger than a critical value function (CVF) of the data. We
illustrate this procedure when regressors are highly persistent, a case in
which commonly-used simulation methods encounter difficulties controlling size
uniformly. Our approach works satisfactorily, controls size, and yields a test
which outperforms the two other known similar tests.


title: Rectangular diagrams of surfaces: representability

abstract:
  We introduce a simple combinatorial way, which we call a rectangular diagram
of a surface, to represent a surface in the three-sphere. It has a particularly
nice relation to the standard contact structure on $\mathbb S^3$ and to
rectangular diagrams of links. By using rectangular diagrams of surfaces we are
going, in particular, to develop a method to distinguish Legendrian knots. This
requires a lot of technical work of which the present paper addresses only the
first basic question: which isotopy classes of surfaces can be represented by a
rectangular diagram. Vaguely speaking the answer is this: there is no
restriction on the isotopy class of the surface, but there is a restriction on
the rectangular diagram of the boundary link that can arise from the
presentation of the surface. The result extends to Giroux's convex surfaces for
which this restriction on the boundary has a natural meaning. In a subsequent
paper we are going to consider transformations of rectangular diagrams of
surfaces and to study their properties. By using the formalism of rectangular
diagrams of surfaces we also produce here an annulus in $\mathbb S^3$ that we
expect to be a counterexample to the following conjecture: if two Legendrian
knots cobound an annulus and have zero Thurston--Bennequin numbers relative to
this annulus, then they are Legendrian isotopic.


title: Improved Techniques for Training GANs

abstract:
  We present a variety of new architectural features and training procedures
that we apply to the generative adversarial networks (GANs) framework. We focus
on two applications of GANs: semi-supervised learning, and the generation of
images that humans find visually realistic. Unlike most work on generative
models, our primary goal is not to train a model that assigns high likelihood
to test data, nor do we require the model to be able to learn well without
using any labels. Using our new techniques, we achieve state-of-the-art results
in semi-supervised classification on MNIST, CIFAR-10 and SVHN. The generated
images are of high quality as confirmed by a visual Turing test: our model
generates MNIST samples that humans cannot distinguish from real data, and
CIFAR-10 samples that yield a human error rate of 21.3%. We also present
ImageNet samples with unprecedented resolution and show that our methods enable
the model to learn recognizable features of ImageNet classes.


title: Inner radius of nodal domains of quantum ergodic eigenfunctions

abstract:
  In this short note we show that the lower bounds of Mangoubi on the inner
radius of nodal domains can be improved for quantum ergodic sequences of
eigenfunctions, according to a certain power of the radius of shrinking balls
on which the eigenfunctions equidistribute. We prove such improvements using a
quick application of our recent results (arXiv:1606.02057), which give modified
growth estimates for eigenfunctions that equidistribute on small balls. Since
by the results of Han and Hezari-Rivi\`ere small scale QE holds for negatively
curved manifolds on logarithmically shrinking balls, we get logarithmic
improvements on the inner radius of such manifolds. We also get improvements
for manifolds with ergodic geodesic flows. In addition using the small scale
equidistribution results of Lester-Rudnick, one gets polynomial betterments of
for toral eigenfunctions in dimensions $n \geq 3$. The results work only for a
full density subsequence of eigenfunctions.


title: Characterizations of product Hardy spaces in Bessel setting

abstract:
  In this paper, we work in the setting of Bessel operators and Bessel Laplace
equations studied by Weinstein, Huber, and the harmonic function theory in this
setting introduced by Muckenhoupt--Stein, especially the generalised
Cauchy--Riemann equations and the conjugate harmonic functions. We provide the
equivalent characterizations of product Hardy spaces associated with Bessel
operators in terms of the Bessel Riesz transforms, non-tangential and radial
maximal functions defined via Poisson and heat semigroups, based on the atomic
decomposition, the extension of Merryfield's result which connects the product
non-tangential maximal function and area function, and on the grand maximal
function technique which connects the product non-tangential and radial maximal
function. We then obtain directly the decomposition of the product BMO space
associated with Bessel operators. These results are a first extension for
product Hardy and BMO associated to a differential operator other than the
Laplacian and are a major step beyond the Chang--Fefferman setting.


title: Search for a muonic dark force at BABAR

abstract:
  Many models of physics beyond the Standard Model predict the existence of new
Abelian forces with new gauge bosons mediating interactions between "dark
sectors" and the Standard Model. We report a search for a dark boson Z'
coupling only to the second and third generations of leptons in the reaction
e+e- -> mu+mu- Z', Z' -> mu+mu- using 514 fb-1 of data collected by the BABAR
experiment. No significant signal is observed for Z' masses in the range 0.212
- 10 GeV. Limits on the coupling parameter g' as low as 7x10^-4 are derived,
leading to improvements in the bounds compared to those previously derived from
neutrino experiments.


title:
Intelligent audit code generation from free text in the context of
  neurosurgery

abstract:
  Clinical auditing requires codified data for aggregation and analysis of
patterns. However in the medical domain obtaining structured data can be
difficult as the most natural, expressive and comprehensive way to record a
clinical encounter is through natural language. The task of creating structured
data from naturally expressed information is known as information extraction.
Specialised areas of medicine use their own language and data structures; the
translation process has unique challenges, and often requires a fresh approach.
This research is devoted to creating a novel semi-automated method for
generating codified auditing data from clinical notes recorded in a
neurosurgical department in an Australian teaching hospital. The method
encapsulates specialist knowledge in rules that instantaneously make precise
decisions for the majority of the matches, followed up by dictionary-based
matching of the remaining text.


title:
Green Information Technology as Administrative innovation -
  Organizational factors for successful implementation: Literature Review

abstract:
  There is a considerable amount of awareness of environmental issues and
corporate responsibility for sustainability. As such, from a technological
viewpoint, Green IT has become an important topic in contemporary
organizations. Consequently, organisations are expected to be innovative in
their business practices to become more sustainable. Yet, the popularity and
adoption of such initiatives amongst employees remain low. Furthermore, the
management practices for adhering to Green IT are largely dormant, lacking
active incentives for employees to engage in Green IT initiatives. This study
observes the phenomenon of Green IT through administrative innovation. In doing
so this paper performs a comprehensive analysis of 137 papers published between
2007 and 2015. The paper reveals organizational factors for successful
implementation of Green IT as administrative innovation that can be useful to
both academia and practice.


title:
Incoherent Tensor Norms and Their Applications in Higher Order Tensor
  Completion

abstract:
  In this paper, we investigate the sample size requirement for a general class
of nuclear norm minimization methods for higher order tensor completion. We
introduce a class of tensor norms by allowing for different levels of
coherence, which allows us to leverage the incoherence of a tensor. In
particular, we show that a $k$th order tensor of rank $r$ and dimension
$d\times\cdots\times d$ can be recovered perfectly from as few as
$O((r^{(k-1)/2}d^{3/2}+r^{k-1}d)(\log(d))^2)$ uniformly sampled entries through
an appropriate incoherent nuclear norm minimization. Our results demonstrate
some key differences between completing a matrix and a higher order tensor:
They not only point to potential room for improvement over the usual nuclear
norm minimization but also highlight the importance of explicitly accounting
for incoherence, when dealing with higher order tensors.

categories: math.ST cs.IT math.IT math.OC stat.ML stat.TH


title: Almost-Prime Polynomials with Prime Arguments

abstract:
  We improve Irving's method of the double-sieve by using the DHR sieve. By
extending the upper and lower sieve functions into their respective
non-elementary ranges, we are able to make improvements on the previous records
on the number of prime factors of irreducible polynomials at prime arguments.
In particular, we prove that irreducible quadratics over $\mathbb{Z}$
satisfying necessary local conditions are $P_4$ infinitely often.


title:
Ethical Implications of IT-enabled Information Flows Conceived as
  Intermediaries or Mediators

abstract:
  This paper contributes to a better understanding of ethical concerns
regarding the deployment of complex public sector IT systems and the
information flows they instigate. The paper aims to reveal how different views
on IT and IT-enabled information flows allow us to see differently their social
implications and to construe different ethical questions. This is achieved by
i) defining two opposing views on IT-enabled information flows as
'intermediaries' and 'mediators'; ii) by analysing the controversial case of My
School - a web portal that provides performance data of 9,500 Australian
schools - that introduces new information flows in the education sector; and
iii) by revealing and explaining how some unintended negative social
implications emerge and how the articulation of ethical concerns depends on the
view on My School-enabled information flows. The paper concludes with
theoretical and practical implications, with particular emphasis on
responsibilities of all involved, setting up foundations for an important area
of future IS research.


title: Social value and information quality in online health information search

abstract:
  This paper extends and validates a model of value-driven online healthcare
information search in online shared contexts. Perceived value is an important
factor behind users' decisions concerning search, consumption and reuse of
products and services. The role of utilitarian, hedonic and epistemic value of
information in user satisfaction and intention to repeat online search is well
recognized, but little support has been found for social value affecting user
satisfaction critical for such decisions. Therefore, a value-based model of
online healthcare information search was extended adding detailed information
quality measures. Our survey data collected from 143 college going students
from more than 10 countries studying in South Korea demonstrated two novel
results. At first, unlike existing studies, strong support was found for
perceived social value affecting the user satisfaction. As a second substantial
finding, the significance of social value could only be appreciated by using
comprehensive constructs of information quality than simpler measures.
Therefore, this study shows for social and shared HIS, users consider access,
representation and context quality of healthcare information to be more
important from social perspective than intrinsic (or content) quality.
Therefore, developers and healthcare organizations interested in traction of
their online healthcare information delivery systems (HIS), especially those
using internet and social media networks, should focus on enhancing information
quality of their systems accordingly.


title:
Distributed Machine Learning in Materials that Couple Sensing,
  Actuation, Computation and Communication

abstract:
  This paper reviews machine learning applications and approaches to detection,
classification and control of intelligent materials and structures with
embedded distributed computation elements. The purpose of this survey is to
identify desired tasks to be performed in each type of material or structure
(e.g., damage detection in composites), identify and compare common approaches
to learning such tasks, and investigate models and training paradigms used.
Machine learning approaches and common temporal features used in the domains of
structural health monitoring, morphable aircraft, wearable computing and
robotic skins are explored. As the ultimate goal of this research is to
incorporate the approaches described in this survey into a robotic material
paradigm, the potential for adapting the computational models used in these
applications, and corresponding training algorithms, to an amorphous network of
computing nodes is considered. Distributed versions of support vector machines,
graphical models and mixture models developed in the field of wireless sensor
networks are reviewed. Potential areas of investigation, including possible
architectures for incorporating machine learning into robotic nodes, training
approaches, and the possibility of using deep learning approaches for automatic
feature extraction, are discussed.


title:
A design science exploration of a visual-spatial learning system with
  feedback

abstract:
  Our paper is research in progress that is research investigating the use of
games technology to enhance the learning of a physical skill. The Microsoft
Kinect is a system designed for gaming with the capability to track the
movement of users. Our research explored whether such a system could be used to
provide feedback when teaching sign vocabulary. Whilst there are technologies
available for teaching sign language, currently none provide feedback on the
accuracy of the users' attempts at making signs. In this paper we report how
the three-dimensional dsplay capability of the technology can enhance the
users' experience. Also, when using tracking to identify errors in physical
movements, how and when should feedback be given. A design science approach was
undertaken to find a solution to this real world problem. The design and
implementation of the solution provides interesting insights into how
technology can not only emulate but also improve upon traditional learning of
physical skills.


title:
Defining and Conceptualizing Actionable Insight: A Conceptual Framework
  for Decision-centric Analytics

abstract:
  Despite actionable insight is widely recognized as the outcome of data
analytics, there is a lack of a systematic and commonly-shared definition for
the term. More importantly, existing definitions are generally too abstract for
informing the design of data analytics systems. This study proposes a
definition for actionable insight in data analytics. For this purpose, this
study conceptualizes actionable insight as a multi-component concept. The
components, namely analytics insight, synergic insight, and prognostic insights
are grounded in theories from multiple disciplines. Collectively, the
components provide a holistic definition for actionable insight. Based on the
multi-component view, a conceptual framework is introduced to actionable
insight in detail, at both the concept-level and component-level. Each
component's analytical, cognitive, and computational requirements are explained
and relevant design considerations are suggested. We hope this study could be a
rudimentary step toward the realization of data-centric data analytics that can
deliver the promised actionable insight.


title: Business Intelligence and Supply Chain Agility

abstract:
  Supply Chain Agility is important for organisations to stay competitive in
today's dynamic business environment. There is increasing interest in deploying
Business Intelligence (BI) in the Supply Chain Management (SCM) context to
improve Supply Chain (SC) Agility. However, there is limited research exploring
BI contributions to SC Agility. In this research-in-progress paper we propose a
model based on a conceptual analysis of the literature showing how BI can help
organisations achieve SC Agility by supporting the key areas of SCM (Plan,
Source, Make, Deliver and Return). In the next stage of this project, we will
conduct a series of case studies investigating how organisations use BI when
managing their SC activities and how BI contributes to SC Agility. The result
of the study will help organizations deploy BI effectively to support SCM and
improve SC Agility.


title: Mid Infrared View of the High Mass Star Formation Region W51A

abstract:
  In this paper we present the results of a mid infrared study of G49.5-0.4, or
W51A, part of the massive starbirth complex W51. Combining public data from the
$Spitzer$ IRAC camera, and Gemini mid infrared camera T-ReCS at 7.73, 9.69,
12.33 and 24.56 \micron, with spatial resolution of $\sim$0.5\arcsec, we have
identified the mid infrared counterparts of 8 ultracompact HII regions, showing
that two radio sources are deeply embedded in molecular clouds and another is a
cloud of ionized gas. From the T-ReCS data we have unveiled the central core of
W51 region, revealing massive young stellar candidates. We modeled the spectral
energy distribution of the detected sources suggesting the embedded objects are
sources with spectral types ranging from B3 to O5, but the majority of the fits
indicate stellar objects with B1 spectral types. We also present an extinction
map of IRS~2, showing that a region with lower extinction corresponds to the
region where a proposed jet of gas has impacted the foreground cloud. From this
map, we also derived the total extinction towards the enigmatic source IRS~2E,
which amounts to $\sim$60 magnitudes in the $V$ band. We calculated the color
temperature due to thermal emission of the circumstellar dust of the detected
sources; the temperatures are in the interval of $\sim$100 -- 150 K, which
corresponds to the emission of dust located at 0.1 pc from the central source.
Finally, we show a possible mid infrared counterpart of a detected source at mm
wavelengths that was found by \cite{zap08,zap09} to be a massive young stellar
object undergoing a high accretion rate.


title:
The challenges and opportunities of delivering wireless high speed
  broadband services in Rural and Remote Australia: A Case Study of Western
  Downs Region (WDR)

abstract:
  This paper critically assesses wireless broadband internet infrastructure, in
the rural and remote communities of WDR in terms of supply, demand and
utilisation. Only 8 of 20 towns have ADSL/ADSL2+, and only 3 towns have 4G
mobile network coverage. Conversely all of the towns have 2G/3G mobile network
coverage but have problems with speed, reliability of service and capacity to
handle data traffic loads at peak times. Satellite broadband internet for
remote areas is also patchy at best. Satisfaction with existing wireless
broadband internet services is highly variable across rural and remote
communities in WDR. Finally we provide suggestions to improve broadband
internet access for rural and remote communities. Public and private investment
and sharing of wired and wireless broadband internet infrastructure is needed
to provide the backhaul networks and 4G mobile and fixed wireless services to
ensure high speed, reliable and affordable broadband services for rural and
remote communities.


title: Spin-Orbit Coupling and Spin Textures in Optical Superlattices

abstract:
  We proposed and demonstrated a new approach for realizing spin orbit coupling
with ultracold atoms. We use orbital levels in a double well potential as
pseudospin states. Two-photon Raman transitions between left and right wells
induce spin-orbit coupling. This scheme does not require near resonant light,
features adjustable interactions by shaping the double well potential, and does
not depend on special properties of the atoms. A pseudospinor Bose-Einstein
condensate spontaneously acquires an antiferromagnetic pseudospin texture which
breaks the lattice symmetry similar to a supersolid.


title:
Synchrotron Emission from Dark Matter in Galactic Subhalos. A Look into
  the Smith Cloud

abstract:
  One of the key predictions of the WIMP paradigm for Dark Matter (DM) is that
DM particles can annihilate into charged particles. These annihilations will
proceed in e.g. Galactic subhalos such as dwarf Galaxies or, as recently
pointed out, high velocity clouds such as the "Smith Cloud". In this note, we
focus on the radio emission associated with DM annihilations into electrons and
positrons occurring in the Smith Cloud. The phenomenology of this emission is
discussed in quite some detail. We argue that the uncertainties in the
propagation can be captured by the typical diffusion-loss length parameter
(Syrovatskii variable) but that the angle-integrated radio fluxes are
independent of the propagation. We conclude that if the Smith Cloud is indeed
dominated by DM, radio signals from DM annihilation stand out amongst other
messengers. Furthermore, low frequencies such as the ones observed by e.g. the
Low Frequency Array (LOFAR) and the next-generation Square Kilometre Array
(SKA) are optimal for searches for DM in the Smith Cloud. As a practical
application, we set conservative constraints on dark matter annihilation cross
section using data of continuum radio emission from the Galaxy at 22 MHz and at
1.4 GHz. Stronger constraints could be reached by background subtraction,
exploiting the profile and frequency dependence of the putative DM signal. We
set stronger but tentative limits using the median noise in brightness
temperature from the Green Bank Telescope and the LOFAR sensitivities.


title: Dynamics and scattering of a massless particle

abstract:
  We estimate the probability of a photon to move faster than light, under the
Einstein dynamics which, unlike the wave equation or Maxwell wave dynamics, has
singular dispersion relation at zero momentum. We show that this probability
goes to zero with time, using propagation estimates suitably multi-scaled to
control the contribution of low frequencies. We then prove minimal velocity
bounds


title: Thermal x-ray diffraction and near-field phase contrast imaging

abstract:
  Using higher-order coherence of thermal light sources, the resolution power
of standard x-ray imaging techniques can be enhanced. In this work, we applied
the higher-order measurement to far-field x-ray diffraction and near-field
phase contrast imaging (PCI), in order to achieve superresolution in x-ray
diffraction and obtain enhanced intensity contrast in PCI. The cost of
implementing such schemes is minimal compared to the methods that achieve
similar effects by using entangled x-ray photon pairs.


title: Intra-Binary Shock Heating of Black Widow Companions

abstract:
  The low mass companions of evaporating binary pulsars (black widows and their
ilk) are strongly heated on the side facing the pulsar. However in high-quality
photometric and spectroscopic data the heating pattern does not match that
expected for direct pulsar illumination. Here we explore heating mediated by an
intra-binary shock (IBS). We develop a simple analytic model and implement it
in the popular `ICARUS' light curve code. The model is parameterized by the
wind momentum ratio beta and velocity v_Rel v_orb and assumes that the
reprocessed pulsar wind emits prompt particles or radiation to heat the
companion surface. We illustrate an interesting range of light curve
asymmetries controlled by these parameters. The code also computes the IBS
synchrotron emission pattern, and thus can model black widow X-ray light
curves. As a test we apply the results to the high quality asymmetric optical
light curves of PSR J2215+5135; the resulting fit gives a substantial
improvement upon direct heating models and produces an X-ray light curve
consistent with that seen. The IBS model parameters imply that, at the present
loss rate, the companion evaporation has a characteristic timescale tau_evap
~150My. Still, the model is not fully satisfactory, indicating additional
unmodeled physical effects.


title:
Dual Immaculate Quasisymmetric Functions Expand Positively into Young
  Quasisymmetric Schur Functions

abstract:
  We describe a combinatorial formula for the coefficients when the dual
immaculate quasisymmetric functions are decomposed into Young quasisymmetric
Schur functions. We prove this using an analogue of Schensted insertion. Using
this result, we give necessary and sufficient conditions for a dual immaculate
quasisymmetric function to be symmetric. Moreover, we show that the product of
a Schur function and a dual immaculate quasisymmetric function expands
positively in the Young quasisymmetric Schur basis. We also discuss the
decomposition of the Young noncommutative Schur functions into the immaculate
functions. Finally, we provide a Remmel-Whitney-style rule to generate the
coefficients of the decomposition of the dual immaculates into the Young
quasisymmetric Schurs algorithmically and an analogous rule for the
decomposition of the dual bases.