title: Remarks on the pion-nucleon sigma-term

abstract:
  The pion-nucleon $\sigma$-term can be stringently constrained by the
combination of analyticity, unitarity, and crossing symmetry with
phenomenological information on the pion-nucleon scattering lengths. Recently,
lattice calculations at the physical point have been reported that find lower
values by about $3\sigma$ with respect to the phenomenological determination.
We point out that a lattice measurement of the pion-nucleon scattering lengths
could help resolve the situation by testing the values extracted from
spectroscopy measurements in pionic atoms.


title: Tidally Induced Offset Disks in Magellanic Spiral Galaxies

abstract:
  Magellanic spiral galaxies are a class of one-armed systems that often
exhibit an offset stellar bar, and are rarely found around massive spiral
galaxies. Using a set of N-body and hydrodynamic simulations we consider a
dwarf-dwarf galaxy interaction as the driving mechanism for the formation of
this peculiar class of systems. We investigate here the relation between the
dynamical, stellar and gaseous disk center and the bar. In all our simulations
the bar center always coincides with the dynamical center, while the stellar
disk becomes highly asymmetric during the encounter causing the photometric
center of the Magellanic galaxy disk to become mismatched with both the bar and
the dynamical center. The disk asymmetries persist for almost 2 Gyrs, the time
that it takes for the disk to be re-centered with the bar, and well after the
companion has passed. This explains the nature of the offset bar found in many
Magellanic-type galaxies, including the Large Magellanic Cloud (LMC) and NGC
3906. In particular, these results, once applied to the LMC, suggest that the
dynamical center should reside in the bar center instead of the HI center as
previously assumed, pointing to a variation in the current estimate of the
north component of the LMC proper motion.


title:
Rotation curve fitting and its fatal attraction to cores in
  realistically simulated galaxy observations

abstract:
  We study the role of systematic effects in observational studies of the
cusp-core problem under the minimum disc approximation using a suite of
high-resolution (25-pc softening length) hydrodynamical simulations of dwarf
galaxies. We mimic realistic kinematic observations and fit the mock rotation
curves with two analytic models commonly used to differentiate cores from cusps
in the dark matter distribution. We find that the cored pseudo-isothermal
sphere (ISO) model is strongly favoured by the reduced $\chi^2_\nu$ of the fits
in spite of the fact that our simulations contain cuspy Navarro-Frenk-White
profiles (NFW). We show that even idealized measurements of the gas circular
motions can lead to the incorrect answer if velocity underestimates induced by
pressure support, with a typical size of order $\sim$5 km s$^{-1}$ in the
central kiloparsec, are neglected. Increasing the spatial resolution of the
mock observations leads to more misleading results because the inner region,
where the effect of pressure support is most significant, is better sampled.
Fits to observations with a spatial resolution of 100 pc (2 arcsec at 10 Mpc)
favour the ISO model in 78-90 per cent of the cases, while at 800-pc
resolution, 40-78 per cent of the galaxies indicate the fictitious presence of
a dark matter core. The coefficients of our best-fit models agree well with
those reported in observational studies; therefore, we conclude that NFW haloes
can not be ruled out reliably from this type of analysis.


title: The NMSSM lives: with the 750 GeV diphoton excess

abstract:
  We propose an NMSSM scenario that can explain the excess in the diphoton
spectrum at 750 GeV recently observed by ATLAS and CMS. We show that in a
certain limit with a very light pseudoscalar one can reproduce the experimental
results without invoking exotic matter. The 750 GeV excess is produced by two
resonant heavy Higgs bosons with masses ~750 GeV, that subsequently decay to
two light pseudoscalars. Each of these decays to collimated photon pairs that
appear as a single photon in the electromagnetic calorimeter. A mass gap
between heavy Higgses mimics a large width of the 750 GeV peak. The production
mechanism, containing a strong component via initial b quarks, ameliorates a
possible tension with 8 TeV data compared to other production modes. We also
discuss other constraints, in particular from low energy experiments. Finally,
we discuss possible methods that could distinguish our proposal from other
physics models describing the diphoton excess in the Run-II of the LHC.


title:
Synchrotron Magnetic Fields from Rayleigh-Taylor Instability in
  Supernovae

abstract:
  Synchrotron emission from a supernova necessitates a magnetic field, but it
is unknown how strong the relevant magnetic fields are, and what mechanism
generates them. In this study, we perform high-resolution numerical gas
dynamics calculations to determine the growth of turbulence due to
Rayleigh-Taylor instability, and the resulting kinetic energy in turbulent
fluctuations, to infer the strength of magnetic fields amplified by this
turbulence. We find that Rayleigh-Taylor instability can produce turbulent
fluctuations strong enough to amplify magnetic fields to a few percent of
equipartition with the thermal energy. This turbulence stays concentrated near
the reverse shock, but averaging this magnetic energy throughout the shocked
region (weighting by emissivity) sets the magnetic fields at a minimum of 0.3
percent of equipartition. This suggests a minimum effective magnetic field
strength ($\epsilon_B > 0.003$) which should be present in all interacting
supernovae.


title:
SU(N) transitions in M-theory on Calabi-Yau fourfolds and background
  fluxes

abstract:
  We study M-theory on a Calabi-Yau fourfold with a smooth surface $S$ of
$A_{N-1}$ singularities. The resulting three-dimensional theory has a
$\mathcal{N}=2$ $SU(N)$ gauge theory sector, which we obtain from a twisted
dimensional reduction of a seven-dimensional $\mathcal{N}=1$ $SU(N)$ gauge
theory on the surface $S$. A variant of the Vafa-Witten equations governs the
moduli space of the gauge theory, which, for a trivial $SU(N)$ principal bundle
over $S$, admits a Coulomb and a Higgs branch. In M-theory these two gauge
theory branches arise from a resolution and a deformation to smooth Calabi-Yau
fourfolds, respectively. We find that the deformed Calabi-Yau fourfold
associated to the Higgs branch requires for consistency a non-trivial four-form
background flux in M-theory. The flat directions of the flux-induced
superpotential are in agreement with the gauge theory prediction for the moduli
space of the Higgs branch. We illustrate our findings with explicit examples
that realize the Coulomb and Higgs phase transition in Calabi-Yau fourfolds
embedded in weighted projective spaces. We generalize and enlarge this class of
examples to Calabi-Yau fourfolds embedded in toric varieties with an $A_{N-1}$
singularity in codimension two.


title:
Testing the No-Hair Theorem with Observations of Black Holes in the
  Electromagnetic Spectrum

abstract:
  According to the general-relativistic no-hair theorem, astrophysical black
holes depend only on their masses and spins and are uniquely described by the
Kerr metric. Mass and spin are the first two multipole moments of the Kerr
spacetime and completely determine all other moments. The no-hair theorem can
be tested by measuring potential deviations from the Kerr metric which alter
such higher-order moments. In this review, I discuss tests of the no-hair
theorem with current and future observations of such black holes across the
electromagnetic spectrum, focusing on near-infrared observations of the
supermassive black hole at the Galactic center, pulsar-timing and very-long
baseline interferometric observations, as well as X-ray observations of
fluorescent iron lines, thermal continuum spectra, variability, and
polarization.


title: Lyman Alpha Signatures from Direct Collapse Black Holes

abstract:
  `Direct collapse black holes' (DCBHs) provide possible seeds for supermassive
black holes that exist at redshifts as high as z~7. We study Lyman Alpha (Lya)
radiative transfer through simplified representations of the DCBH-scenario. We
find that gravitational heating of the collapsing cloud gives rise to a Lya
cooling luminosity of up to ~ 1e38(M_gas/1e6 Msun)^2 erg/s. The Lya production
rate can be significantly larger during the final stages of collapse, but
collisional deexcitation efficiently suppresses the emerging Lya flux.
Photoionization by a central source boosts the Lya luminosity to
L~1e43(M_BH/1e6 M_sun) erg/s during specific evolutionary stages of the cloud,
where M_BH denotes the mass of the black hole powering this source. We predict
that the width and velocity off-set of the Lya spectral line range from a few
tens to few thousands km/s, depending sensitively on the evolutionary state of
the cloud. We also compare our predictions to observations of CR7 (Sobral et
al. 2015), a luminous Lya emitter at z~7, which is potentially associated with
a DCBH. If CR7 is powered by a black hole, then its Lya flux alone requires
that M_BH> 1e7 M_sun, which exceeds the mass of DCBHs when they first form. The
observed width of the Lya spectrum favors the presence of only a low column
density of hydrogen, log [N_HI/cm^-2]~19-20. The shape of the Lya spectrum
indicates that this gas is outflowing. These requirements imply that if CR7
harbors a DCBH, then the physical conditions that enabled its formation have
been mostly erased, which is in agreement with theoretical expectations.


title:
Quantum reference frames associated with non-compact groups: the case of
  translations and boosts, and the role of mass

abstract:
  Quantum communication without a shared reference frame or the construction of
a relational quantum theory requires the notion of a quantum reference frame.
We analyze aspects of quantum reference frames associated with non-compact
groups, specifically the group of spatial translations and Galilean boosts. We
begin by demonstrating how the usually employed group average, used to dispense
of the notion of an external reference frame, leads to unphysical states when
applied to reference frames associated with non-compact groups. However, we
show that this average does lead naturally to a reduced state on the relative
degrees of freedom of a system, which was previously considered by Angelo et
al. [1]. We then study in detail the informational properties of this reduced
state for systems of two and three particles in Gaussian states.


title: The Higgs mass and natural supersymmetric spectrum from the landscape

abstract:
  In supersymmetric models where the superpotential mu term is generated with
mu<< m_{soft} (e.g. from radiative Peccei-Quinn symmetry breaking or
compactified string models with sequestration and stabilized moduli), and where
the string landscape 1. favors soft supersymmetry (SUSY) breaking terms as
large as possible and 2. where the anthropic condition that electroweak
symmetry is properly broken with a weak scale m_{W,Z,h}~100 GeV ({\it i.e.} not
too weak of weak interactions), then these combined landscape/anthropic
requirements act as an attractor pulling the soft SUSY breaking terms towards
values required by models with radiatively-driven naturalness: near the line of
criticality where electroweak symmetry is barely broken and the Higgs mass is
~125 GeV. The pull on the soft terms serves to ameliorate the SUSY flavor and
CP problems. The resulting sparticle mass spectrum may barely be accessible at
high-luminosity LHC while the required light higgsinos should be visible at a
linear e^+e^- collider with \sqrt{s}>2m(higgsino).


title:
Micro - tidal disruption events by stellar compact objects and the
  production of ultra-long GRBs

abstract:
  We explore full/partial tidal disruption events (TDEs) of stars/planets by
stellar compact objects (Black holes; BHs; or neutron stars; NSs), which we
term micro-TDEs. Disruption of a star/planet with mass $M_{\star}$ may lead to
the formation of a debris disk around the BH/NS. Efficient accretion of a
fraction $(f_{acc}=0.1$ of the debris may then give rise to bright energetic
long ($10^{3}-10^{4}\,s$), X-ray/Gamma-ray flares, with total energies of up to
$(f_{acc}/0.1)\times10^{52}\,(M_{\star}/{0.6\,M_{\odot}})\,$ergs, possibly
resembling ultra-long GRBs/XRFs. The energy of such flares depends on the
poorly constrained accretion processes. Significantly fainter flares might be
produced if most of the disk mass is blown away through strong outflows. We
suggest three dynamical origins for such disruptions. In the first, a
star/planet is tidally disrupted following a close random encounter with a
BH/NS in a dense cluster. We estimate the BH (NS) micro-TDE rates from this
scenario to be few$\times10^{-6}$ (few$\times10^{-7}$) ${\rm yr}^{-1}$ per
Milky-Way galaxy. Another scenario involves the interaction of wide companions
due to perturbations by stars in the field, likely producing comparable but
lower rates. Finally, a third scenario involves a BH/NS which gain a natal
velocity kick at birth, leading to a close encounter with a binary companion
and the tidal disruption of that companion. Such events could be associated
with a supernova, or even with a preceding GRB/XRF event, and would likely
occur hours to days after the prompt explosion; the rates of such events could
be larger than those obtained from the other scenarios, depending on the
preceding complex binary stellar evolution.


title: General relativistic 'screening' in cosmological simulations

abstract:
  We revisit the issue of interpreting the results of large volume cosmological
simulations in the context of large scale general relativistic effects. We look
for simple modifications to the nonlinear evolution of the gravitational
potential $\psi$ that lead on large scales to the correct, fully relativistic
description of density perturbations in the Newtonian gauge. We note that the
relativistic constraint equation for $\psi$ can be cast as a diffusion
equation, with a diffusion length scale determined by the expansion of the
Universe. Exploiting the weak time evolution of $\psi$ in all regimes of
interest, this equation can be further accurately approximated as a Helmholtz
equation, with an effective relativistic 'screening' scale $\ell$ related to
the Hubble radius. We demonstrate that it is thus possible to carry out N-body
simulations in the Newtonian gauge by replacing Poisson's equation with this
Helmholtz equation, involving a trivial change in the Green's function kernel.
Our results also motivate a simple, approximate (but very accurate) gauge
transformation - $\delta_{\rm N}(\mathbf{k}) \approx \delta_{\rm
sim}(\mathbf{k})\times (k^2+\ell^{-2})/k^2$ - to convert the density field
$\delta_{\rm sim}$ of standard collisionless N-body simulations (initialised in
the comoving synchronous gauge) into the Newtonian gauge density $\delta_{\rm
N}$ at arbitrary times. A similar conversion can also be written in terms of
particle positions. Our results can be interpreted in terms of a Jeans
stability criterion induced by the expansion of the Universe. The appearance of
the screening scale $\ell$ in the evolution of $\psi$, in particular, leads to
a natural resolution of the 'Jeans swindle' in the presence of super-horizon
modes.


title: Spatially Resolved Galactic Wind in Lensed Galaxy RCSGA 032727-132609

abstract:
  We probe the spatial distribution of outflowing gas along four lines of sight
separated by up to 6 kpc in a gravitationally-lensed star-forming galaxy at
z=1.70. Using MgII and FeII emission and absorption as tracers, we find that
the clumps of star formation are driving galactic outflows with velocities of
-170 to -250 km/sec. The velocities of MgII emission are redshifted with
respect to the systemic velocities of the galaxy, consistent with being
back-scattered. By contrast, the FeII fluorescent emission lines are either
slightly blueshifted or at the systemic velocity of the galaxy. Taken together,
the velocity structure of the MgII and FeII emission is consistent with arising
through scattering in galactic winds. Assuming a thin shell geometry for the
out owing gas, the estimated masses carried out by these outfows are large (>
30 - 50 $\rm{M_{\odot} yr^{-1}}$), with mass loading factors several times the
star-formation rate. Almost 20% to 50% of the blueshifted absorption probably
escapes the gravitational potential of the galaxy. In this galaxy, the outflow
is "locally sourced", that is, the properties of the outflow in each line of
sight are dominated by the properties of the nearest clump of star formation;
the wind is not global to the galaxy. The mass outflow rates and the momentum
flux carried out by outflows in individual star forming knots of this object
are comparable to that of starburst galaxies in the local Universe.


title:
Modeling Seven Years of Event Horizon Telescope Observations with
  Radiatively Inefficient Accretion Flow Models

abstract:
  An initial three-station version of the Event Horizon Telescope, a
millimeter-wavelength very-long baseline interferometer, has observed
Sagittarius A* (Sgr A*) repeatedly from 2007 to 2013, resulting in the
measurement of a variety of interferometric quantities. Of particular
importance, there is now a large set of closure phases, measured over a number
of independent observing epochs. We analyze these observations within the
context of a realization of semi-analytic radiatively inefficient disk models,
implicated by the low luminosity of Sgr A*. We find a broad consistency among
the various observing epochs and between different interferometric data types,
with the latter providing significant support for this class of models of Sgr
A*. The new data significantly tighten existing constraints on the spin
magnitude and its orientation within this model context, finding a spin
magnitude of $a=0.10^{+0.30+0.56}_{-0.10-0.10}$, an inclination with respect to
the line of sight of
$\theta={60^\circ}^{+5^\circ+10^\circ}_{-8^\circ-13^\circ}$, and a position
angle of $\xi={156^\circ}^{+10^\circ+14^\circ}_{-17^\circ-27^\circ}$ east of
north. These are in good agreement with previous analyses. Notably, the
previous $180^\circ$ degeneracy in the position angle has now been conclusively
broken by the inclusion of the closure phase measurements. A reflection
degeneracy in the inclination remains, permitting two localizations of the spin
vector orientation, one of which is in agreement with the orbital angular
momentum of the infrared gas cloud G2 and the clockwise disk of young stars.
This possibly supports a relationship between Sgr A*'s accretion flow and these
larger-scale features.


title: The Galaxy in Context: Structural, Kinematic and Integrated Properties

abstract:
  Our Galaxy, the Milky Way, is a benchmark for understanding disk galaxies. It
is the only galaxy whose formation history can be studied using the full
distribution of stars from white dwarfs to supergiants. The oldest components
provide us with unique insight into how galaxies form and evolve over billions
of years. The Galaxy is a luminous (L-star) barred spiral with a central
box/peanut bulge, a dominant disk, and a diffuse stellar halo. Based on global
properties, it falls in the sparsely populated "green valley" region of the
galaxy colour-magnitude diagram. Here we review the key integrated, structural
and kinematic parameters of the Galaxy, and point to uncertainties as well as
directions for future progress. Galactic studies will continue to play a
fundamental role far into the future because there are measurements that can
only be made in the near field and much of contemporary astrophysics depends on
such observations.


title: Anisotropic Diffusion in Mesh-Free Numerical Magnetohydrodynamics

abstract:
  We extend recently-developed mesh-free Lagrangian methods for numerical
magnetohydrodynamics (MHD) to arbitrary anisotropic diffusion equations,
including: passive scalar diffusion, Spitzer-Braginskii conduction and
viscosity, cosmic ray diffusion/streaming, anisotropic radiation transport,
non-ideal MHD (Ohmic resistivity, ambipolar diffusion, the Hall effect), and
turbulent 'eddy diffusion.' We study these as implemented in the code GIZMO for
both new meshless finite-volume Godunov schemes (MFM/MFV). We show the MFM/MFV
methods are accurate and stable even with noisy fields and irregular particle
arrangements, and recover the correct behavior even in arbitrarily anisotropic
cases. They are competitive with state-of-the-art AMR/moving-mesh methods, and
can correctly treat anisotropic diffusion-driven instabilities (e.g. the MTI
and HBI, Hall MRI). We also develop a new scheme for stabilizing anisotropic
tensor-valued fluxes with high-order gradient estimators and non-linear flux
limiters, which is trivially generalized to AMR/moving-mesh codes. We also
present applications of some of these improvements for SPH, in the form of a
new integral-Godunov SPH formulation that adopts a moving-least squares
gradient estimator and introduces a flux-limited Riemann problem between
particles.


title:
Searching for bulk motions in the ICM of massive, merging clusters with
  Chandra CCD data

abstract:
  We search for bulk motions in the intracluster medium (ICM) of massive
clusters showing evidence of an ongoing or recent major merger with spatially
resolved spectroscopy in {\sl Chandra} CCD data. We identify a sample of 6
merging clusters with $>$150 ks {\sl Chandra} exposure in the redshift range
$0.1 < z < 0.3$. By performing X-ray spectral analysis of projected ICM regions
selected according to their surface brightness, we obtain the projected
redshift maps for all of these clusters. After performing a robust analysis of
the statistical and systematic uncertainties in the measured X-ray redshift
$z_{\rm X}$, we check whether or not the global $z_{\rm X}$ distribution
differs from that expected when the ICM is at rest. We find evidence of
significant bulk motions at more than 3$\sigma$ in A2142 and A115, and less
than 2$\sigma$ in A2034 and A520. Focusing on single regions, we identify
significant localized velocity differences in all of the merging clusters. We
also perform the same analysis on two relaxed clusters with no signatures of
recent mergers, finding no signs of bulk motions, as expected. Our results
indicate that deep {\sl Chandra} CCD data enable us to identify the presence of
bulk motions at the level of $v_{\rm BM} >$ 1000\ ${\rm km\ s^{-1}}$ in the ICM
of massive merging clusters at $0.1<z<0.3$. Although the CCD spectral
resolution is not sufficient for a detailed analysis of the ICM dynamics, {\sl
Chandra} CCD data constitute a key diagnostic tool complementing X-ray
bolometers on board future X-ray missions.


title: Towards a world-sheet description of doubled geometry in string theory

abstract:
  Starting from a sigma-model for a doubled target-space geometry, we show that
the number of target-space dimensions can be reduced by half through a gauging
procedure. We apply this formalism to a class of backgrounds relevant for
double field theory, and illustrate how choosing different gaugings leads to
string-theory configurations T-dual to each other. We furthermore discuss that
given a conformal doubled theory, the reduced theories are conformal as well.
  As an example we consider the three-dimensional SU(2) WZW model and show that
the only possible reduced backgrounds are the cigar and trumpet CFTs in two
dimensions, which are indeed T-dual to each other.


title: Black holes as collapsed polymers

abstract:
  We propose that a large Schwarzschild black hole (BH) is a bound state of
highly excited, long, closed strings at the Hagedorn temperature. The size of
the bound state is smaller than the string random-walk scale and determined
dynamically by the string attractive interactions. It is further proposed that
the effective free-energy density of the bound state should be expressed as a
function of its entropy density. For a macroscopic BH, the free-energy density
contains only linear and quadratic terms, in analogy with that of a collapsed
polymer when expressed as a function of the polymer concentration. Using the
effective free energy, we derive scaling relations for the entropy, energy and
size of the bound state and show that these agree with the scaling relations of
the BH; in particular, with the area law for the BH entropy. The area law
originates from the inverse scaling of the effective temperature with the
bound-state radius. We also find that the energy density of the bound state is
equal to its pressure.


title: Isotopic Ratios of Carbon and Oxygen in Titan's CO using ALMA

abstract:
  We report interferometric observations of carbon monoxide (CO) and its
isotopologues in Titan's atmosphere using the Atacama Large
Millimeter/submillimeter Array (ALMA). The following transitions were detected:
CO (J = 1-0, 2-1, 3-2, 6-5), $^{13}$CO (J = 2-1, 3-2, 6-5), C$^{18}$O (J = 2-1,
3-2), and C$^{17}$O (J = 3-2). Molecular abundances and the vertical
atmospheric temperature profile were derived by modeling the observed emission
line profiles using NEMESIS, a line-by-line radiative transfer code. We present
the first spectroscopic detection of $^{17}$O in the outer solar system with
C$^{17}$O detected at > 8$\sigma$ confidence. The abundance of CO was
determined to be 49.6 ${\pm}$ 1.8 ppm, assumed to be constant with altitude,
with isotopic ratios $^{12}$C/$^{13}$C = 89.9 ${\pm}$ 3.4, $^{16}$O/$^{18}$O =
486 ${\pm}$ 22, and $^{16}$O/$^{17}$O = 2917${\pm}$359. The measurements of
$^{12}$C/$^{13}$C and $^{16}$O/$^{18}$O ratios are the most precise values
obtained in Titan's atmospheric CO to date. Our results are in good agreement
with previous studies and suggest no significant deviations from standard
terrestrial isotopic ratios.


title: SU(2) x SU(2) x U(1) Interpretation on the 750 GeV Diphoton Excess

abstract:
  We propose that the SU(2) x SU(2) x U(1) (aka G221) models could provide us a
750 GeV scalar resonance that may account for the diphoton excess observed at
the LHC while satisfying present collider constraints. The neutral component of
the $SU(2)_R$ scalar multiplet can be identified as the 750 GeV scalar. In the
lepto-phobic and fermio-phobic G221 models the new charged gauge boson W' could
be light, and we find that the diphoton decay width could be dominated by the
loop contribution from the $W'$. To initiate gluon fusion production, it is
necessary to extend the G221 symmetry to the Pati-Salam and SO(10) symmetry. We
investigate the possibilities that the light colored scalars or vectorlike
fermions survive in the SO(10) theory and provide large gluon fusion rate for
the diphoton signature. It is possible to test the G221 interpretation by
direct searches of W' using the multi-gauge boson production channel at the Run
2 LHC.


title: The Speedster-EXD- A New Event-Driven Hybrid CMOS X-ray Detector

abstract:
  The Speedster-EXD is a new 64x64 pixel, 40 $\mu$m pixel pitch, 100 $\mu$m
depletion depth hybrid CMOS X-ray detector (HCD) with the capability of reading
out only those pixels containing event charge, thus enabling fast effective
frame rates. A global charge threshold can be specified, and pixels containing
charge above this threshold are flagged and read out. The Speedster detector
has also been designed with other advanced in-pixel features to improve
performance, including a low-noise, high-gain CTIA amplifier that eliminates
interpixel capacitance crosstalk (IPC), and in-pixel Correlated Double Sampling
(CDS) subtraction to reduce reset noise. We measure the best energy resolution
on the Speedster-EXD detector to be 206 eV (3.5 %) at 5.89 keV and 172 eV (10.0
%) at 1.49 keV. The average IPC to the four adjacent pixels is measured to be
0.25 $\pm$ 0.2 % (i.e. consistent with zero). The pixel-to-pixel gain variation
is measured to be 0.80 $\pm$ 0.03 %, and a Monte Carlo simulation is applied to
better characterize the contributions to the energy resolution.


title:
Using the 2-MASS Photometric Redshift Survey to optimize LIGO Follow-Up
  Observations

abstract:
  The initial discovery of LIGO on 14 September 2015 was the inspiral merger
and ring-down of the black hole binary at a distance of about 500~Mpc or a
redshift of about 0.1. The search for electromagnetic counterparts for the
inspiral of binary black holes is impeded by coarse initial source
localisations and a lack of a compelling model for the counterpart; therefore,
rapid electromagnetic follow-up is required to understand the astrophysical
context of these sources. Because astrophysical sources of gravitational
radiation are likely to reside in galaxies, it would make sense to search first
in regions where the LIGO-Virgo probability is large and where the density of
galaxies is large as well. Under the assumption that the probability of a
gravitational-wave event from a given region of space is proportional to the
density of galaxies within the probed volume, one can calculate an improved
localisation of the position of the source simply by multiplying the LIGO-Virgo
skymap by the density of galaxies in the range of redshifts. We propose using
the 2-MASS Photometric Redshift Galaxy Catalogue for this purpose and
demonstrate that using it can dramatically reduce the search region for
electromagnetic counterparts.


title:
The Evolution of 21-cm Structure (EOS): public, large-scale simulations
  of Cosmic Dawn and Reionization

abstract:
  We introduce the Evolution of 21-cm Structure (EOS) project: providing
periodic, public releases of the latest cosmological 21-cm simulations. 21-cm
interferometry is set to revolutionize studies of the Cosmic Dawn (CD) and
epoch of reionization (EoR), eventually resulting in 3D maps of the first
billion years of our Universe. Progress will depend on sophisticated data
analysis pipelines, which are in turn tested on large-scale mock observations.
Here we present the 2016 EOS data release, consisting of the largest (1.6 Gpc
on side with a 1024^3 grid), public 21-cm simulations of the CD and EoR. We
include calibrated, sub-grid prescriptions for inhomogeneous recombinations and
photo-heating suppression of star formation in small mass galaxies. We present
two simulation runs that approximately bracket the contribution from faint
unseen galaxies. From these two extremes, we predict that the duration of
reionization (defined as a change in the mean neutral fraction from 0.9 to 0.1)
should be between 2.7 < Delta z < 5.7. The large-scale 21-cm power during the
advanced EoR stages can be different by up to a factor of ~10, depending on the
model. This difference has a comparable contribution from: (i) the typical bias
of sources; and (ii) a more efficient negative feedback in models with an
extended EoR driven by faint galaxies. We also make detectability forecasts.
With a 1000h integration, HERA and SKA1-low should achieve a signal-to-noise of
~few-hundreds throughout the EoR/CD, while in the maximally optimistic scenario
of perfect foreground cleaning, all instruments should make a statistical
detection of the cosmic signal. We also caution that our ability to clean
foregrounds determines the relative performance of narrow/deep vs. wide/shallow
surveys expected with SKA1. Our 21-cm power spectra, simulation outputs and
visualizations are publicly available.


title: Magnetically-Charged Black Branes and Viscosity/Entropy Ratios

abstract:
  We consider asymptotically-AdS $n$-dimensional black brane solutions in a
theory of gravity coupled to a set of $N$ $p$-form field strengths, in which
the field strengths carry magnetic charges. For appropriately chosen charges,
the metrics are isotropic in the $(n-2)$ transverse directions. However, in
general the field strength configurations break the full Euclidean symmetry of
the $(n-2)$-dimensional transverse space. We then study the linearised equation
for transverse traceless metric perturbations in these backgrounds, and by
employing the Kubo formula we obtain expressions for $\eta/S$, the ratio of
shear viscosity to entropy density. We find that the KSS bound on the ratio
$\eta/S$ is generally violated in these solutions. We also extend the
discussion by including also a dilatonic scalar field in the theory, leading to
solutions that are asymptotically Lifshitz with hyperscaling violation.


title: A monotonicity result for the $q-$fractional operator

abstract:
  In this article we prove that if the $q-$fractional operator
$(~_{q}\nabla_{qa}^\alpha y)(t)$ of order $0<\alpha\leq 1$ , $0<q<1$ and
starting at some $qa \in T_q=\{q^k: k \in \mathbb{Z}\}\cup \{0\},~~a>0$ is
positive such that $y(a) \geq 0$, then $y(t)$ is $c_q(\alpha)-$increasing,
$c_q(\alpha)=\frac{1-q^\alpha}{1-q}q^{1-\alpha}$. Conversely, if y(t) is
increasing and $y(a)\geq 0$, then $(~_{q}\nabla_{qa}^\alpha y)(t)\geq 0$. As an
application, we proved a $q-$fractional version of the Mean-Value Theorem.


title: Learning values across many orders of magnitude

abstract:
  Most learning algorithms are not invariant to the scale of the function that
is being approximated. We propose to adaptively normalize the targets used in
learning. This is useful in value-based reinforcement learning, where the
magnitude of appropriate value approximations can change over time when we
update the policy of behavior. Our main motivation is prior work on learning to
play Atari games, where the rewards were all clipped to a predetermined range.
This clipping facilitates learning across many different games with a single
learning algorithm, but a clipped reward function can result in qualitatively
different behavior. Using the adaptive normalization we can remove this
domain-specific heuristic without diminishing overall performance.


title: Regular Language Distance and Entropy

abstract:
  This paper addresses the problem of determining the distance between two
regular languages. It will show how to expand Jaccard distance, which works on
finite sets, to potentially-infinite regular languages. The entropy of a
regular language plays a large role in the extension. Much of the paper is
spent investigating the entropy of a regular language. This includes addressing
issues that have required previous authors to rely on the upper limit of
Shannon's traditional formulation of entropy, because its limit does not always
exist. The paper also includes proposing a new limit based formulation for the
entropy of a regular language and proves that formulation to both exist and be
equivalent to Shannon's original formulation (when it exists). Additionally,
the proposed formulation is shown to equal an analogous but formally quite
different notion of topological entropy from Symbolic Dynamics -- consequently
also showing Shannon's original formulation to be equivalent to topological
entropy. Surprisingly, the natural Jaccard-like entropy distance is trivial in
most cases. Instead, the {\it entropy sum} distance metric is suggested, and
shown to be granular in certain situations.


title: Quantum Query as a State Decomposition

abstract:
  The Quantum Query Model is a framework that allows us to express most known
quantum algorithms. Algorithms represented by this model consist on a set of
unitary operators acting over a finite Hilbert space, and a final measurement
step consisting on a set of projectors. In this work, we prove that the
application of these unitary operators before the measurement step is
equivalent to decomposing a unit vector into a sum of vectors and then
inverting some of their relative phases. We also prove that the vectors of that
sum must fulfill a list of properties and we call such vectors a Block Set. If
we define the measurement step for the Block Set Formulation similarly to the
Quantum Query Model, then we prove that both formulations give the same Gram
matrix of output states, although the Block Set Formulation allows a much more
explicit form. Therefore, the Block Set reformulation of the Quantum Query
Model gives us an alternative interpretation on how quantum algorithms works.
Finally, we apply our approach to the analysis and complexity of quantum exact
algorithms.


title:
A physical zero-knowledge object-comparison system for nuclear warhead
  verification

abstract:
  Zero-knowledge proofs are mathematical cryptographic methods to demonstrate
the validity of a claim while providing no further information beyond the claim
itself. The possibility of using such proofs to process classified and other
sensitive physical data has attracted attention, especially in the field of
nuclear arms control. Here we demonstrate a non-electronic fast neutron
differential radiography technique using superheated emulsion detectors that
can confirm that two objects are identical without revealing their geometry or
composition. Such a technique could form the basis of a verification system
that could confirm the authenticity of nuclear weapons without sharing any
secret design information. More broadly, by demonstrating a physical
zero-knowledge proof that can compare physical properties of objects, this
experiment opens the door to developing other such secure proof-systems for
other applications.


title:
Vertically bounded double diffusive convection in the fingering regime:
  comparing no-slip vs free-slip boundary conditions

abstract:
  Vertically bounded fingering double diffusive convection (DDC) is numerically
investigated, focusing on the influences of different velocity boundary
conditions, i.e. the no-slip condition which is inevitable in the lab-scale
experimental research, and the free-slip condition which is an approximation
for the interfaces in many natural environments, such as the oceans. For both
boundary conditions the flow is dominated by fingers and the global responses
follow the same scaling laws, with enhanced prefactors for the free-slip cases.
Therefore, the laboratory experiments with the no-slip boundaries serve as a
good model for the finger layers in the ocean. Moreover, in the free-slip case
although the tangential shear stress is eliminated at the boundaries, the local
dissipation rate in the near-wall region may exceed the value found in the
no-slip cases, which is caused by the stronger vertical motions of fingers and
sheet structures near the free-slip boundaries. This counter intuitive result
might be relevant for properly estimating and modelling the mixing and
entrainment phenomena at free-surfaces and interfaces.


title: Carbon gas in SMC low-metallicity star-forming regions

abstract:
  This paper presents [CII], [CI] and CO emission line maps of the star-forming
regions N66, N25+N26, and N88 in the metal-poor Local Group dwarf galaxy SMC.
The spatial and velocity structure of the large HII region N66 reveals an
expanding ring of shocked molecular gas centered on the exciting star cluster
NGC346, whereas a more distant dense molecular cloud is being eroded by UV
radiation from the same cluster. In the N25+N26 and N88 maps, diffuse [CII]
emission at a relatively low surface brightness extends well beyond the compact
boundaries of the bright emission associated with the [CII] regions. In all
regions, the distribution of this bright [CII] emission and the less prominent
[CI] emission closely follows the outline of the CO complexes, but the
intensity of the [CII] and [CI] emission is generally anticorrelated, which can
be understood by the action of photodissociation and photoionization processes.
Notwithstanding the overall similarity of CO and [CII] maps, the intensity
ratio of these lines varies significantly, mostly due to changes in CO
brightness. [CII] emission line profiles are up to 50% wider in velocity than
corresponding CO profiles. A radiative transfer analysis shows that the [CII]
line is the dominant tracer of (CO-dark) molecular hydrogen in the SMC. CO
emission traces only a minor fraction of the total amount of gas. The
similarity of the spatial distribution and line profile shape, and the
dominance of molecular gas associated with [[CII] rather than CO emission imply
that in the low-metallicity environment of the SMC the small amount of dense
molecular gas traced by CO is embedded in the much more extended molecular gas
traced only by [CII] emission. The contribution from neutral atomic and ionized
hydrogen zones is negligible in the star-forming regions observed.


title: A Field Guide to Personalized Reserve Prices

abstract:
  We study the question of setting and testing reserve prices in single item
auctions when the bidders are not identical. At a high level, there are two
generalizations of the standard second price auction: in the lazy version we
first determine the winner, and then apply reserve prices; in the eager version
we first discard the bidders not meeting their reserves, and then determine the
winner among the rest. We show that the two versions have dramatically
different properties: lazy reserves are easy to optimize, and A/B test in
production, whereas eager reserves always lead to higher welfare, but their
optimization is NP-complete, and naive A/B testing will lead to incorrect
conclusions. Despite their different characteristics, we show that the overall
revenue for the two scenarios is always within a factor of 2 of each other,
even in the presence of correlated bids. Moreover, we prove that the eager
auction dominates the lazy auction on revenue whenever the bidders are
independent or symmetric. We complement our theoretical results with
simulations on real world data that show that even suboptimally set eager
reserve prices are preferred from a revenue standpoint.


title: Toward Game Level Generation from Gameplay Videos

abstract:
  Algorithms that generate computer game content require game design knowledge.
We present an approach to automatically learn game design knowledge for level
design from gameplay videos. We further demonstrate how the acquired design
knowledge can be used to generate sections of game levels. Our approach
involves parsing video of people playing a game to detect the appearance of
patterns of sprites and utilizing machine learning to build a probabilistic
model of sprite placement. We show how rich game design information can be
automatically parsed from gameplay videos and represented as a set of
generative probabilistic models. We use Super Mario Bros. as a proof of
concept. We evaluate our approach on a measure of playability and stylistic
similarity to the original levels as represented in the gameplay videos.


title: From Bethe-Salpeter Wave Functions to Generalised Parton Distributions

abstract:
  We review recent works on the modelling of Generalised Parton Distributions
within the Dyson-Schwinger formalism. We highlight how covariant computations,
using the impulse approximation, allows one to fulfil most of the theoretical
constraints of the GPDs. Specific attention is brought to chiral properties and
especially the so-called soft pion theorem, and its link with the Axial-Vector
Ward-Takahashi identity. The limitation of the impulse approximation are also
explained. Beyond impulse approximation computations are reviewed in the
forward case. Finally, we stress the advantages of the overlap of lightcone
wave functions, and possible ways to construct covariant GPD models within this
framework, in a two-body approximation.


title: Superradiant amplification by stars and black holes

abstract:
  In this thesis we study the phenomenon of superradiance and its implications
to the stability of black-holes (BH) and perfect-fluid stars.
  Superradiance is a radiation enhancement process that involves rotating
dissipative systems. In BH spacetimes, superradiance is due to dissipation at
the event horizon, with interesting associated phenomena, namely floating
orbits and BH-bombs. BH superradiance is a very interdisciplinary topic, and
its study allows us to obtain important results in the area of particle
physics. The scattering of a scalar field by a rotating BH leads to the
formation of quasi-boundstates. In rotational systems, these states can give
rise to superradiant instabilities. These results were recently used to impose
constraints to the mass of fundamental particles and darkmatter candidates.
  In this work, it is shown that, when dissipation is properly included,
similar results are achievable in self-gravitating systems other than
black-holes, such as perfect fluid stars. It is also demonstrated that the
relativistic effects related to the phenomenon of frame-dragging are
neglectable in this calculation.


title:
Three-Dimensional Alexandrov spaces with positive or nonnegative Ricci
  curvature

abstract:
  We study closed three-dimensional Alexandrov spaces with a lower Ricci
curvature bound in the $\mathsf{CD}^*(K,N)$ sense, focusing our attention on
those with positive or nonnegative Ricci curvature. First, we show that a
closed three-dimensional $\mathsf{CD}^*(2,3)$-Alexandrov space must be
homeomorphic to a spherical space form or to the suspension of $\mathbb{R}P^2$.
We then classify closed three-dimensional $\mathsf{CD}^*(0,3)$-Alexandrov
spaces.


title: Student understanding of Symmetry and Gauss' law

abstract:
  Helping students learn why Gauss' law can or cannot be easily applied to
determine the strength of the electric field at various points for a particular
charge distribution, and then helping them learn to determine the shape of the
Gaussian surfaces if sufficient symmetry exists can develop their reasoning and
problem solving skills. We investigate the difficulties that students in
calculus-based introductory physics courses have with the concepts of symmetry,
electric field and electric flux that are pivotal to Gauss' law of electricity.
Determination of the electric field using Gauss' law requires discerning the
symmetry of a particular charge distribution and being able to predict the
direction of the electric field everywhere if a high symmetry exists. It
requires a good grasp of how to add the electric field vectors using the
principle of superposition, and the concepts of area vector and electric flux.
We administered free response and multiple-choice questions and conducted
interviews with individual students using a think-aloud protocol to elucidate
the difficulties students have with the concepts of symmetry, electric field
and electric flux. Here, we discuss student responses to some questions on a
multiple-choice test administered to them. The test can be used as a teaching
and assessment tool.


title: Adaptive Learning with Robust Generalization Guarantees

abstract:
  The traditional notion of generalization---i.e., learning a hypothesis whose
empirical error is close to its true error---is surprisingly brittle. As has
recently been noted in [DFH+15b], even if several algorithms have this
guarantee in isolation, the guarantee need not hold if the algorithms are
composed adaptively. In this paper, we study three notions of
generalization---increasing in strength---that are robust to postprocessing and
amenable to adaptive composition, and examine the relationships between them.
We call the weakest such notion Robust Generalization. A second, intermediate,
notion is the stability guarantee known as differential privacy. The strongest
guarantee we consider we call Perfect Generalization. We prove that every
hypothesis class that is PAC learnable is also PAC learnable in a robustly
generalizing fashion, with almost the same sample complexity. It was previously
known that differentially private algorithms satisfy robust generalization. In
this paper, we show that robust generalization is a strictly weaker concept,
and that there is a learning task that can be carried out subject to robust
generalization guarantees, yet cannot be carried out subject to differential
privacy. We also show that perfect generalization is a strictly stronger
guarantee than differential privacy, but that, nevertheless, many learning
tasks can be carried out subject to the guarantees of perfect generalization.


title: Boosting low-mass hadronic resonances

abstract:
  Searches for new hadronic resonances typically focus on high-mass spectra,
due to overwhelming QCD backgrounds and detector trigger rates. We present a
study of searches for relatively low-mass hadronic resonances at the LHC in the
case that the resonance is boosted by recoiling against a well-measured
high-$p_{\textrm{T}}$ probe such as a muon, photon or jet. The hadronic decay
of the resonance is then reconstructed either as a single large-radius jet or
as a resolved pair of standard narrow-radius jets, balanced in transverse
momentum to the probe. We show that the existing 2015 LHC dataset of $pp$
collisions with $\int\mathcal{L}dt = 4\ \mathrm{fb}^{-1}$ should already have
powerful sensitivity to a generic $Z'$ model which couples only to quarks, for
$Z'$ masses ranging from 20-500 GeV/c$^2$.


title:
Density matrix reconstruction of three-level atoms via Rydberg
  electromagnetically induced transparency

abstract:
  We present combined measurements of the spatially-resolved optical spectrum
and the total excited-atom number in an ultracold gas of three-level atoms
under electromagnetically induced transparency conditions involving high-lying
Rydberg states. The observed optical transmission of a weak probe laser at the
center of the coupling region exhibits a double peaked spectrum as a function
of detuning, whilst the Rydberg atom number shows a comparatively narrow single
resonance. By imaging the transmitted light onto a charge-coupled-device
camera, we record hundreds of spectra in parallel, which are used to map out
the spatial profile of Rabi frequencies of the coupling laser. Using all the
information available we can reconstruct the full one-body density matrix of
the three-level system, which provides the optical susceptibility and the
Rydberg density as a function of spatial position. These results help elucidate
the connection between three-level interference phenomena, including the
interplay of matter and light degrees of freedom and will facilitate new
studies of many-body effects in optically driven Rydberg gases.


title:
The Cover Time of Deterministic Random Walks for General Transition
  Probabilities

abstract:
  The deterministic random walk is a deterministic process analogous to a
random walk. While there are some results on the cover time of the rotor-router
model, which is a deterministic random walk corresponding to a simple random
walk, nothing is known about the cover time of deterministic random walks
emulating general transition probabilities. This paper is concerned with the
SRT-router model with multiple tokens, which is a deterministic process coping
with general transition probabilities possibly containing irrational numbers.
For the model, we give an upper bound of the cover time, which is the first
result on the cover time of deterministic random walks for general transition
probabilities. Our upper bound also improves the existing bounds for the
rotor-router model in some cases.


title: Closed and asymptotic formulas for energy of some circulant graphs

abstract:
  We consider circulant graphs G(r,N) where the vertices are the integers
modulo N and the neighbours of 0 are {-r,...,-1,1,...,r}. The energy of G(r,N)
is a trigonometric sum of N*r terms. For low values of r we compute this sum
explicitly. We also study the asymptotics of the energy of G(r,N) for big N.
There is a known integral formula for the linear growth coefficient, we find a
new expression of the form of a finite trigonometric sum with r terms. As an
application we show that in the family G(r,N) for r less or equal than 4 there
is a finite number of hyperenergetic graphs. On the other hand, for each r>4
there is at most a finite number of non-hyperenergetic graphs of the form
G(r,N). Finally we show that the graph G(r,2r+1) minimizes the energy among all
the regular graphs of degree 2r.


title: Initial Access in 5G mm-Wave Cellular Networks

abstract:
  The massive amounts of bandwidth available at millimeter-wave frequencies
(roughly above 10 GHz) have the potential to greatly increase the capacity of
fifth generation cellular wireless systems. However, to overcome the high
isotropic pathloss experienced at these frequencies, high directionality will
be required at both the base station and the mobile user equipment to establish
sufficient link budget in wide area networks. This reliance on directionality
has important implications for control layer procedures. Initial access in
particular can be significantly delayed due to the need for the base station
and the user to find the proper alignment for directional transmission and
reception. This paper provides a survey of several recently proposed techniques
for this purpose. A coverage and delay analysis is performed to compare various
techniques including exhaustive and iterative search, and Context Information
based algorithms. We show that the best strategy depends on the target SNR
regime, and provide guidelines to characterize the optimal choice as a function
of the system parameters.


title: The Potential of Resource Sharing in 5G Millimeter-Wave Bands

abstract:
  With the severe spectrum shortage in conventional cellular bands, the
millimeter (mmWave) frequencies, roughly above 10~GHz, have been attracting
growing attention for next-generation micro- and pico- cellular wireless
networks. A fundamental and open question is how these bands should be used by
cellular operators. Cellular spectrum has been traditionally allocated
following an exclusive ownership model. However, in this paper we argue that
the distinct nature of mmWave communication -- the massive bandwidth degrees of
freedom, directional isolation and high susceptibility to blockage -- suggest
that spectrum and infrastructure sharing between multiple operators may be
necessary to exploit the full potential of these bands. High-level capacity
analyses are presented that reveal significant possible gains under spectrum
and infrastructure sharing, even under minimal coordination between operators.
Moreover, we discuss how network technologies including software defined
networks (SDNs) and network function virtualization (NFV) can easily enable
resource sharing by having a programmable core entity provide transparent
inter-operator access to the end user.


title:
Comparison of Attitude Estimation Techniques for Low-cost Unmanned
  Aerial Vehicles

abstract:
  Attitude estimation for small, low-cost unmanned aerial vehicles is often
achieved using a relatively simple complementary filter that combines onboard
accelerometers, gyroscopes, and magnetometer sensing. This paper explores the
limits of performance of such attitude estimation, with a focus on performance
in highly dynamic maneuvers. The complementary filter is derived along with the
extended Kalman filter and unscented Kalman filter to evaluate the potential
performance gains when using a more sophisticated estimator. Simulations are
presented that compare performance across a range of test cases, many where
ground truth was generated from manually controlled flights in a flight
simulator. Estimator scenarios that are generic across the different estimator
types (such as the way sensor information is processed, and the use of
dynamically changing gains) are compared across the test cases. An appendix is
included as a quick reference for the common attitude representations and their
kinematic expressions.


title:
On the distances between Latin squares and the smallest defining set
  size

abstract:
  In this note we show that for each Latin square $L$ of order $n\geq 2$, there
exists a Latin square $L'\neq L$ of order $n$ such that $L$ and $L'$ differ in
at most $8\sqrt{n}$ cells. Equivalently, each Latin square of order $n$
contains a Latin trade of size at most $8\sqrt{n}$. We also show that the size
of the smallest defining set in a Latin square is $\Omega(n^{3/2})$. %That is,
there are constants $c$ and $n_0$ such that for any $n>n_0$ the size of the
smallest defining %set of order $n$ is at least $cn^{3/2}$.


title:
Phonon Monte Carlo: Generating Random Variates for Thermal Transport
  Simulation

abstract:
  Phonon Monte Carlo (PMC) is a versatile stochasic technique for solving the
Boltzmann transport equation for phonons. It is particularly well suited for
analyzing thermal transport in structures that have real-space roughness or are
too large to simulate directly using atomistic techniques. PMC hinges on the
generation and use of \textit{random variates} -- specific values of the random
variables that correspond to physical observables -- in a way that accurately
and efficiently captures the appropriate distribution functions. We present the
relative merits of the inversion and rejection techniques for generating random
variates on several examples relevant in thermal transport: drawing phonons
from a thermal distribution and with full or isotropic dispersion, randomizing
outgoing momentum upon diffuse boundary scattering, implementing contacts
(boundary and internal), and conserving energy in the simulation. We also
identify common themes in phonon generation and scattering that are helpful for
reusing code in the simulation (generating thermal-phonon attributes vs
internal contacts; diffuse surface scattering vs boundary contacts). We hope
these examples will inform the reader about the mechanics of random-variate
generation and how to choose a good approach for whatever problem is at hand,
and aid in the more widespread use of PMC for thermal transport simulation.


title:
Robust Air Data Sensor Fault Diagnosis With Enhanced Fault Sensitivity
  Using Moving Horizon Estimation

abstract:
  This paper investigates robust fault diagnosis of multiple air data sensor
faults in the presence of winds. The trade-off between robustness to winds and
sensitivity to faults is challenging due to simultaneous influence of winds and
latent faults on monitored sensors. Different from conventional residual
generators that do not consider any constraints, we propose a constrained
residual generator using moving horizon estimation. The main contribution is
improved fault sensitivity by exploiting known bounds on winds in residual
generation. By analyzing the Karush-Kuhn-Tucker conditions of the formulated
moving horizon estimation problem, it is shown that this improvement is
attributed to active inequality constraints caused by faults. When the
weighting matrices in the moving horizon estimation problem are tuned to
increase robustness to winds, its fault sensitivity does not simply decrease as
one would expect in conventional unconstrained residual generators. Instead,
its fault sensitivity increases when the fault is large enough to activate some
inequality constraints. This fault sensitivity improvement is not restricted to
this particular application, but can be achieved by any general moving horizon
estimation based residual generator. A high-fidelity Airbus simulator is used
to illustrate the advantage of our proposed approach in terms of fault
sensitivity.


title: Controlling Excited-State Contamination in Nucleon Matrix Elements

abstract:
  We present a detailed analysis of methods to reduce statistical errors and
excited-state contamination in the calculation of matrix elements of quark
bilinear operators in nucleon states. All the calculations were done on a 2+1
flavor ensemble with lattices of size $32^3 \times 64$ generated using the
rational hybrid Monte Carlo algorithm at $a=0.081$~fm and with $M_\pi=312$ MeV.
The statistical precision of the data is improved using the all-mode-averaging
method. We compare two methods for reducing excited-state contamination: a
variational analysis and a two-state fit to data at multiple values of the
source-sink separation $t_{\rm sep}$. We show that both methods can be tuned to
significantly reduce excited-state contamination and discuss their relative
advantages and cost-effectiveness. A detailed analysis of the size of source
smearing used in the calculation of quark propagators and the range of values
of $t_{\rm sep}$ needed to demonstrate convergence of the isovector charges of
the nucleon to the $t_{\rm sep} \to \infty $ estimates is presented.


title: Radio Pulsars: The Neutron Star Population & Fundamental Physics

abstract:
  Radio pulsars are unique laboratories for a wide range of physics and
astrophysics. Understanding how they are created, how they evolve and where we
find them in the Galaxy, with or without binary companions, is highly
constraining of theories of stellar and binary evolution. Pulsars' relationship
with a recently discovered variety of apparently different classes of neutron
stars is an interesting modern astrophysical puzzle which we consider in Part I
of this review. Radio pulsars are also famous for allowing us to probe the laws
of nature at a fundamental level. They act as precise cosmic clocks and, when
in a binary system with a companion star, provide indispensable venues for
precision tests of gravity. The different applications of radio pulsars for
fundamental physics will be discussed in Part II. We finish by making mention
of the newly discovered class of astrophysical objects, the Fast Radio Bursts,
which may or may not be related to radio pulsars or neutron stars, but which
were discovered in observations of the latter.


title:
The Artin-Springer Theorem for quadratic forms over semi-local rings
  with finite residue fields

abstract:
  Let $R$ be a commutative and unital semi-local ring in which 2 is invertible.
In this note, we show that anisotropic quadratic spaces over $R$ remain
anisotropic after base change to any odd-degree finite \'{e}tale extension of
$R$. This generalization of the classical Artin-Springer theorem (concerning
the situation where $R$ is a field) was previously established in the case
where all residue fields of $R$ are infinite by I. Panin and U. Rehmann. The
more general result presented here permits to extend a fundamental isotropy
criterion of I. Panin and K. Pimenov for quadratic spaces over regular
semi-local domains containing a field of characteristic $\neq 2$ to the case
where the ring has at least one residue field which is finite.


title: Teaching practices of graduate teaching assistants

abstract:
  Physics education research has consistently shown that students have higher
learning outcomes when enrolled in interactive-engagement courses.
Consequently, many schools are actively reforming their introductory curricula.
For courses where the interactive sections (labs, tutorials, and/or workshops)
are mostly taught by graduate student teaching assistants (TAs), good TAs are
instrumental to the success of the reform. Many studies have investigated
specific interactions between TAs and students, but more can be learned through
a holistic examination of TA-student interactions. Over the course of one
semester, I observed TAs in their various teaching roles using the Real-time
Instructor Observation Tool (RIOT). These observations serve to show what TAs
may "default to" with little to no intervention. I present a snapshot of a
department in the early stages of reform and discuss the implications of my
findings as they relate to the professional development of our TAs.


title: Sunspot Numbers from ISOON: A Ten-Year Data Analysis

abstract:
  Sunspot numbers are important tracers of historical solar activity. They are
important in the prediction of oncoming solar maximum, in the design of
lifetimes of space assets, and in assessing the extent of solar-radiation
impact on the space environment. Sunspot numbers were obtained visually from
sunspot drawings. The availability of digital images from the US Air Force
Improved Solar Optical Observing Network (ISOON) prototype telescope concurrent
to observer-dependent sunspot numbers recorded at the National Solar
Observatory (NSO) has provided a basis for comparing sunspot numbers determined
from the two methods. We compare sunspot numbers from visual and digital
methods observed nearly simultaneously. The advantages of digital imagery are
illustrated.


title:
Muon Flux Measurements at the Davis Campus of the Sanford Underground
  Research Facility with the Majorana Demonstrator Veto System

abstract:
  We report the first measurement of the total MUON flux underground at the
Davis Campus of the Sanford Underground Research Facility at the 4850 ft level.
Measurements were done with the Majorana Demonstrator veto system arranged in
two different configurations. The measured total flux is (5.31+/-0.17) x 10^-9
muons/s/cm^2.


title:
Channel Models for Multi-Level Cell Flash Memories Based on Empirical
  Error Analysis

abstract:
  We propose binary discrete parametric channel models for multi-level cell
(MLC) flash memories that provide accurate ECC performance estimation by
modeling the empirically observed error characteristics under program/erase
(P/E) cycling stress. Through a detailed empirical error characterization of
1X-nm and 2Y-nm MLC flash memory chips from two different vendors, we observe
and characterize the overdispersion phenomenon in the number of bit errors per
ECC frame. A well studied channel model such as the binary asymmetric channel
(BAC) model is unable to provide accurate ECC performance estimation. Hence we
propose a channel model based on the beta-binomial probability distribution
(2-BBM channel model) which is a good fit for the overdispersed empirical error
characteristics and show through statistical tests and simulation results for
BCH, LDPC and polar codes, that the 2-BBM channel model provides accurate ECC
performance estimation in MLC flash memories.


title: Multi-mode TES bolometer optimization for the LSPE-SWIPE instrument

abstract:
  In this paper we explore the possibility of using transition edge sensor
(TES) detectors in multi-mode configuration in the focal plane of the Short
Wavelength Instrument for the Polarization Explorer (SWIPE) of the
balloon-borne polarimeter Large Scale Polarization Explorer (LSPE) for the
Cosmic Microwave Background (CMB) polarization. This study is motivated by the
fact that maximizing the sensitivity of TES bolometers, under the augmented
background due to the multi-mode design, requires a non trivial choice of
detector parameters. We evaluate the best parameter combination taking into
account scanning strategy, noise constraints, saturation power and operating
temperature of the cryostat during the flight.


title: Interdependent Network Formation Games

abstract:
  Designing optimal interdependent networks is important for the robustness and
efficiency of national critical infrastructures. Here, we establish a
two-person game-theoretic model in which two network designers choose to
maximize the global connectivity independently. This framework enables
decentralized network design by using iterative algorithms. After a finite
number of steps, the algorithm will converge to a Nash equilibrium, and yields
the equilibrium topology of the network. We corroborate our results by using
numerical experiments, and compare the Nash equilibrium solutions with their
team solution counterparts. The experimental results of the game method and the
team method provide design guidelines to increase the efficiency of the
interdependent network formation games. Moreover, the proposed game framework
can be generally applied to a diverse number of applications, including power
system networks and international air transportation networks.


title:
Interactive video tutorials for enhancing problem solving, reasoning,
  and meta-cognitive skills of introductory physics students

abstract:
  We discuss the development of interactive video tutorial-based problems to
help introductory physics students learn effective problem solving heuristics.
The video tutorials present problem solving strategies using concrete examples
in an interactive environment. They force students to follow a systematic
approach to problem solving and students are required to solve sub-problems
(research-guided multiple choice questions) to show their level of
understanding at every stage of prob lem solving. The tutorials are designed to
provide scaffolding support at every stage of problem solving as needed and
help students view the problem solving process as an opportunity for knowledge
and skill acquisition rather than a "plug and chug" chore. A focus on helping
students learn first to analyse a problem qualitatively, and then to plan a
solution in terms of the relevant physics principles, can be useful for
developing their reasoning skills. The reflection stage of problem solving can
help students develop meta-cognitive skills because they must focus on what
they have learned by solving the problem and how it helps them extend and
organize their knowledge. Preliminary evaluations show that a majority of
students who are unable to solve the tutorial problems without help can solve
similar problems after working through the video tutorial. Further evaluation
to assess the development of useful skills in tutorial learners vs. control
group is underway.


title:
Thermoelectric characterization of fine-grained Ti5O9 Magneli phase
  ceramics

abstract:
  Magneli phase Ti5O9 ceramics with 200-nm grain-size were fabricated by
hot-pressing nanopowders of titanium and anatase TiO2 at 1223 K. The
thermoelectric properties of these ceramics were investigated from room
temperature to 1076 K. We show that the experimental variation of the
electrical conductivity with temperature follows a small-polaron model and that
the Seebeck coefficient can be explained by a temperature-dependent
Heikes-Chaikin-Beni model. The thermoelectric figure-of-merit ZT of this
nanoceramic material reaches 0.3 at 1076 K.


title: DSiD: a Delphes Detector for ILC Physics Studies

abstract:
  We describe DSiD, a fast simulation Delphes detector for the International
Linear Collider (ILC) based on the full simulation performance of the SiD
detector. SiD is one of two detectors described in the ILC Technical Design
Report (TDR). The tracking efficiency, tracking momentum resolution,
electromagnetic and hadronic calorimeter energy resolution, particle
identification and flavor tagging efficiencies are taken from the Detailed
Baseline Design (DBD) study as described in ILC TDR Volume 4: Detectors. In a
cross-check study with $4 \times 10^6$ $e^+ e^- \rightarrow b \bar{b}$ events
generated at $\sqrt{s}=500$ GeV and simulated by Delphes with the DSiD detector
card, these performance characteristics are measured and found to be
commensurate with the DBD results. For a new physics use case example, we
describe a study of Next-to-Minimal Supersymmetric $e^+ e^- \rightarrow 2
\chi_3 \rightarrow 2\chi_1 2 h_1$ with $h_1 \rightarrow 2a_1$ or $h_1
\rightarrow b\bar{b}$ at the $\sqrt{s}=500$ GeV ILC. The card is available on
HepForge.


title: Toward Mention Detection Robustness with Recurrent Neural Networks

abstract:
  One of the key challenges in natural language processing (NLP) is to yield
good performance across application domains and languages. In this work, we
investigate the robustness of the mention detection systems, one of the
fundamental tasks in information extraction, via recurrent neural networks
(RNNs). The advantage of RNNs over the traditional approaches is their capacity
to capture long ranges of context and implicitly adapt the word embeddings,
trained on a large corpus, into a task-specific word representation, but still
preserve the original semantic generalization to be helpful across domains. Our
systematic evaluation for RNN architectures demonstrates that RNNs not only
outperform the best reported systems (up to 9\% relative error reduction) in
the general setting but also achieve the state-of-the-art performance in the
cross-domain setting for English. Regarding other languages, RNNs are
significantly better than the traditional methods on the similar task of named
entity recognition for Dutch (up to 22\% relative error reduction).


title:
A Note on Modeling Self-Suspending Time as Blocking Time in Real-Time
  Systems

abstract:
  This report presents a proof to support the correctness of the schedulability
test for self-suspending real-time task systems proposed by Jane W. S. Liu in
her book titled "Real-Time Systems" (Pages 164-165). The same concept was also
implicitly used by Rajkumar, Sha, and Lehoczky in RTSS 1988 (Page 267) for
analyzing self-suspending behaviour due to synchronization protocols in
multiprocessor systems.


title:
Envelopes of conditional probabilities extending a strategy and a prior
  probability

abstract:
  Any strategy and prior probability together are a coherent conditional
probability that can be extended, generally not in a unique way, to a full
conditional probability. The corresponding class of extensions is studied and a
closed form expression for its envelopes is provided. Then a topological
characterization of the subclasses of extensions satisfying the further
properties of full disintegrability and full strong conglomerability is given
and their envelopes are studied.


title: On the Physics of the Minimal Length: The Question of Gauge Invariance

abstract:
  In this note we discuss the question of gauge invariance in the presence of a
minimal length. This contribution is prepared for the celebration of the 60th
anniversary of the Yang-Mills theory.


title:
Short-range photoassociation from the inner wall of the lowest triplet
  potential of $^{85}$Rb$_2$

abstract:
  Ultracold photoassociation is typically performed at large internuclear
separations, where the scattering wavefunction amplitude is large and
Franck-Condon overlap is maximized. Recently, work by this group and others on
alkali-metal diatomics has shown that photoassociation can efficiently form
molecules at short internuclear distance in both homonuclear and heteronuclear
dimers. We propose that this short-range photoassociation is due to excitation
near the wavefunction amplitude maximum at the inner wall of the lowest triplet
potential. We show that Franck-Condon factors from the highest-energy bound
state can almost precisely reproduce Franck-Condon factors from a low-energy
scattering state, and that both calculations match experimental data from the
near-zero positive-energy scattering state with reasonable accuracy. We also
show that the corresponding photoassociation from the inner wall of the
ground-state singlet potential at much shorter internuclear distance is weaker
and undetectable under our current experimental conditions. We predict from
Franck-Condon factors that the strongest of these weaker short-range
photoassociation transitions are one order of magnitude below our current
sensitivity.


title:
A Compressed Sensing Based Decomposition of Electrodermal Activity
  Signals

abstract:
  The measurement and analysis of Electrodermal Activity (EDA) offers
applications in diverse areas ranging from market research, to seizure
detection, to human stress analysis. Unfortunately, the analysis of EDA signals
is made difficult by the superposition of numerous components which can obscure
the signal information related to a user's response to a stimulus. We show how
simple pre-processing followed by a novel compressed sensing based
decomposition can mitigate the effects of the undesired noise components and
help reveal the underlying physiological signal. The proposed framework allows
for decomposition of EDA signals with provable bounds on the recovery of user
responses. We test our procedure on both synthetic and real-world EDA signals
from wearable sensors and demonstrate that our approach allows for more
accurate recovery of user responses as compared to the existing techniques.


title: Why geometric integration?

abstract:
  Since its emergence, GNI has become the new paradigm in numerical solution of
ODEs, while making significant inroads into numerical PDEs. As often,
yesterday's revolutionaries became the new establishment. This is an excellent
moment to pause and take stock. Have all the major challenges been achieved,
all peaks scaled, leaving just a tidying-up operation? Is there still any point
to GNI as a separate activity or should it be considered as a victim of its own
success and its practitioners depart to fields anew - including new areas of
activity that have been fostered or enabled by GNI?


title: Students' conceptual knowledge of energy and momentum

abstract:
  We investigate student understanding of energy and momentum concepts at the
level of introductory physics by designing and administering a 25-item multiple
choice test and conducting individual interviews. We find that most students
have difficulty in qualitatively interpreting basic principles related to
energy and momentum and in applying them in physical situations. The test
development process and a summary of results are presented.


title: Capacity Limits of Diffusion-Based Molecular Timing Channels

abstract:
  This work introduces capacity limits for molecular timing (MT) channels,
where information is modulated in the release timing of small information
particles, and decoded from the time of arrivals at the receiver. It is shown
that the random time of arrival can be represented as an additive noise
channel, and for the diffusion-based MT (DBMT) channel this noise is
distributed according to the L\'evy distribution. Lower and upper bounds on the
capacity of the DBMT channel are derived for the case where the delay
associated with the propagation of the information particles in the channel is
finite, namely, when the information particles dissipate after a finite time
interval. For the case where a single particle is released per channel use,
these bounds are shown to be tight. When the transmitter simultaneously
releases a large number of particles, the detector at the receiver may not be
able to precisely detect the arrival time of all the particles. Therefore, two
alternative models are considered: detection based on the particle that arrives
first, or detection based on the average arrival times. Tight lower and upper
bounds are derived for these two models. It is shown that by controlling the
maximal delay of the information particles, the capacity can increase
poly-logarithmically with the number of released particles. As each particle
takes a random independent path, this diversity of paths is analogous to
receiver diversity and can be used to considerably increase the achievable data
rates.


title:
A geometric invariant for the study of planar curves and its application
  to spiral tip meander

abstract:
  Planar curves with periodically varying curvature arise in the natural
sciences as the result of a wide variety of periodic processes. The total
curvature of a periodic arc in such curves constrains their symmetry. It is
shown how the total curvature can be computed without reparameterizing the
curve to unit speed. The use of the total curvature of the periodic arcs is
demonstrated through a series of four examples from various branches of
science. Insights gained from these examples are applied to improve the
modeling of spiral wave meander.


title: On conjugacy of Cartan subalgebras in extended affine Lie algebras

abstract:
  That finite-dimensional simple Lie algebras over the complex numbers can be
classified by means of purely combinatorial and geometric objects such as
Coxeter-Dynkin diagrams and indecomposable irreducible root systems, is
arguably one of the most elegant results in mathematics. The definition of the
root system is done by fixing a Cartan subalgebra of the given Lie algebra. The
remarkable fact is that (up to isomorphism) this construction is independent of
the choice of the Cartan subalgebra. The modern way of establishing this fact
is by showing that all Cartan subalgebras are conjugate.
  For symmetrizable Kac-Moody Lie algebras, with the appropriate definition of
Cartan subalgebra, conjugacy has been established by Peterson and Kac. An
immediate consequence of this result is that the root systems and generalized
Cartan matrices are invariants of the Kac-Moody Lie algebras. The purpose of
this paper is to establish conjugacy of Cartan subalgebras for extended affine
Lie algebras; a natural class of Lie algebras that generalizes the
finite-dimensional simple Lie algebra and affine Kac-Moody Lie algebras.


title: Strong mixed-integer formulations for the floor layout problem

abstract:
  The floor layout problem (FLP) tasks a designer with positioning a collection
of rectangular boxes on a fixed floor in such a way that minimizes total
communication costs between the components. While several mixed integer
programming (MIP) formulations for this problem have been developed, it remains
extremely challenging from a computational perspective. This work takes a
systematic approach to constructing MIP formulations and valid inequalities for
the FLP that unifies and recovers all known formulations for it. In addition,
the approach yields new formulations that can provide a significant
computational advantage and can solve previously unsolved instances. While the
construction approach focuses on the FLP, it also exemplifies generic
formulation techniques that should prove useful for broader classes of
problems.


title: Entanglement and correlation functions of the quantum Motzkin spin-chain

abstract:
  We present exact results on the exactly solvable spin chain of Bravyi et al
[Phys. Rev. Lett. 109, 207202 (2012)]. This model is a spin one chain and has a
Hamiltonian that is local and translationally invariant in the bulk. It has a
unique (frustration free) ground state with an energy gap that is polynomially
small in the system's size ($2n$). The half-chain entanglement entropy of the
ground state is $\frac{1}{2}\log n+const.$. Here we first write the Hamiltonian
in the standard spin-basis representation. We prove that at zero temperature,
the magnetization is along the $z-$direction i.e., $\langle
s^{x}\rangle=\langle s^{y}\rangle=0$ (everywhere on the chain). We then
analytically calculate $\langle s^{z}\rangle$ and the two-point correlation
functions of $s^{z}$. By analytically diagonalizing the reduced density
matrices, we calculate the Schmidt rank, von Neumann and R\'enyi entanglement
entropies for: 1. Any partition of the chain into two pieces (not necessarily
in the middle) and 2. $L$ consecutive spins centered in the middle. Further, we
identify entanglement Hamiltonians (Eqs. 49 and 59). We prove a small lemma
(Lemma1) on the combinatorics of lattice paths using the reflection principle
to relate and calculate the Motzkin walk 'height' to spin expected values. We
also calculate the, closely related, (scaled) correlation functions of Brownian
excursions. The known features of this model are summarized in a table in
Sec.I.

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


title:
Low Complexity Sparse Bayesian Learning Using Combined BP and MF with a
  Stretched Factor Graph

abstract:
  This paper concerns message passing based approaches to sparse Bayesian
learning (SBL) with a linear model corrupted by additive white Gaussian noise
with unknown variance. With the conventional factor graph, mean field (MF)
message passing based algorithms have been proposed in the literature. In this
work, instead of using the conventional factor graph, we modify the factor
graph by adding some extra hard constraints (the graph looks like being
`stretched'), which enables the use of combined belief propagation (BP) and MF
message passing. We then propose a low complexity BP-MF SBL algorithm based on
which an approximate BP-MF SBL algorithm is also developed to further reduce
the complexity. Thanks to the use of BP, the BP-MF SBL algorithms show their
merits compared with state-of-the-art MF SBL algorithms: they deliver even
better performance with much lower complexity compared with the vector-form MF
SBL algorithm and they significantly outperform the scalar-form MF SBL
algorithm with similar complexity.


title:
Optimizing the robustness of electrical power systems against cascading
  failures

abstract:
  Electrical power systems are one of the most important infrastructures that
support our society. However, their vulnerabilities have raised great concern
recently due to several large-scale blackouts around the world. In this paper,
we investigate the robustness of power systems against cascading failures
initiated by a random attack. This is done under a simple yet useful model
based on global and equal redistribution of load upon failures. We provide a
complete understanding of system robustness by i) deriving an expression for
the final system size as a function of the size of initial attacks; ii)
deriving the critical attack size after which system breaks down completely;
iii) showing that complete system breakdown takes place through a first-order
(i.e., discontinuous) transition in terms of the attack size; and iv)
establishing the optimal load-capacity distribution that maximizes robustness.
In particular, we show that robustness is maximized when the difference between
the capacity and initial load is the same for all lines; i.e., when all lines
have the same redundant space regardless of their initial load. This is in
contrast with the intuitive and commonly used setting where capacity of a line
is a fixed factor of its initial load.


title: Reinforcement Learning of POMDPs using Spectral Methods

abstract:
  We propose a new reinforcement learning algorithm for partially observable
Markov decision processes (POMDP) based on spectral decomposition methods.
While spectral methods have been previously employed for consistent learning of
(passive) latent variable models such as hidden Markov models, POMDPs are more
challenging since the learner interacts with the environment and possibly
changes the future observations in the process. We devise a learning algorithm
running through episodes, in each episode we employ spectral techniques to
learn the POMDP parameters from a trajectory generated by a fixed policy. At
the end of the episode, an optimization oracle returns the optimal memoryless
planning policy which maximizes the expected reward based on the estimated
POMDP model. We prove an order-optimal regret bound with respect to the optimal
memoryless policy and efficient scaling with respect to the dimensionality of
observation and action spaces.


title: Design of Ultra-compact Graphene-based Superscatterers

abstract:
  The energy-momentum dispersion relation is a fundamental property of
plasmonic systems. In this paper, we show that the method of dispersion
engineering can be used for the design of ultra-compact graphene-based
superscatterers. Based on the Bohr model, the dispersion relation of the
equivalent planar waveguide is engineered to enhance the scattering cross
section of a dielectric cylinder. Bohr conditions with different orders are
fulfilled in multiple dispersion curves at the same resonant frequency. Thus
the resonance peaks from the first and second order scattering terms are
overlapped in the deepsubwavelength scale by delicately tuning the gap
thickness between two graphene layers. Using this ultra-compact graphene-based
superscatterer, the scattering cross section of the dielectric cylinder can be
enhanced by five orders of magnitude.


title: The Impact of Accurate Extinction Measurements for X-ray Spectral Models

abstract:
  Interstellar extinction includes both absorption and scattering of photons
from interstellar gas and dust grains, and it has the effect of altering a
source's spectrum and its total observed intensity. However, while multiple
absorption models exist, there are no useful scattering models in standard
X-ray spectrum fitting tools, such as XSPEC. Nonetheless, X-ray halos, created
by scattering from dust grains, are detected around even moderately absorbed
sources and the impact on an observed source spectrum can be significant, if
modest, compared to direct absorption. By convolving the scattering cross
section with dust models, we have created a spectral model as a function of
energy, type of dust, and extraction region that can be used with models of
direct absorption. This will ensure the extinction model is consistent and
enable direct connections to be made between a source's X-ray spectral fits and
its UV/optical extinction.


title: Breath Activity Detection Algorithm

abstract:
  This report describes the use of a support vector machines with a novel
kernel, to determine the breathing rate and inhalation duration of a fire
fighter wearing a Self-Contained Breathing Apparatus. With this information, an
incident commander can monitor the firemen in his command for exhaustion and
ensure timely rotation of personnel to ensure overall fire fighter safety


title:
On Partial Smoothness, Tilt Stability and the
  $\mathcal{VU}$--Decomposition

abstract:
  Under the assumption of prox-regularity and the presence of a tilt stable
local minimum we are able to show that a $\mathcal{VU}$ like decomposition
gives rise to the existence of a smooth manifold on which the function in
question coincides locally with a smooth function.


title: Adjacent Ramsey theory and Higman's lemma

abstract:
  We show a short proof of Higman's lemma using Friedman's adjacent Ramsey
theorem for pairs. This provides an alternative proof of the known upper bound
for the reverse mathematical status of Higman's lemma and that of its
miniaturised version.


title:
Elements of QED-NRQED Effective Field Theory: I. NLO scattering at
  leading power

abstract:
  The proton radius puzzle, i.e. the large discrepancy in the extraction of the
proton charge radius between regular and muonic hydrogen, challenges our
understanding of the structure of the proton. It can also be an indication of a
new force that couples to muons, but not to electrons. An effective field
theory analysis using Non Relativistic Quantum Electrodynamics (NRQED)
indicates that the muonic hydrogen result can be interpreted as a large,
compared to some model estimates, muon-proton spin-independent contact
interaction. The muonic hydrogen result can be tested by a muon-proton
scattering experiment, MUSE, that is planned at the Paul Scherrer Institute in
Switzerland. The typical momenta of the muons in this experiment are of the
order of the muon mass. In this energy regime the muons are relativistic but
the protons are still non-relativistic. The interaction between the muons and
protons can be described by a hybrid QED-NRQED effective field theory. We
present some elements of this effective field theory. In particular we consider
${\cal O}(Z\alpha)$ scattering up to power $m^2/M^2$, where $m$ ($M$) is the
muon (proton) mass and $Z=1$ for a proton, and ${\cal O}(Z^2\alpha^2)$
scattering at leading power. We show how the former reproduces Rosenbluth
scattering up to power $m^2/M^2$ and the latter the relativistic scattering off
a static potential. Proton structure corrections at ${\cal O}(Z^2\alpha^2)$
will be considered in a subsequent paper.


title:
Point contact tunnelling spectroscopy of the density of states in
  Tb-Mg-Zn quasicrystals

abstract:
  According to theoretical predictions the quasicrystalline (QC) electronic
density of states (DOS) must have a rich and fine spiky structure which
actually has resulted elusive. The problem with its absence may be related to
poor structural characteristics of the studied specimens, and/or to the
non-existence of this spike characteristic. Recent calculations have shown that
the fine structure indeed exists, but only for two dimensional approximants
phases. The aim of the present study is to show our recent experimental studies
with point contacts tunnel junction spectroscopy performed in samples of very
high quality. The studies were performed in icosahedral QC alloys with
composition Tb$_9$Mg$_{35}$Zn$_{56}$. We found the presence of a pseudogap
feature at the Fermi level, small as compared to the pseudogap of other
icosahedral materials. This study made in different spots on the QC shows quite
different spectroscopic features, where the observed DOS was a fine non-spiky
structure, distinct to theoretical predictions. In some regions of the
specimens the spectroscopic features could be related to Kondo characteristics
due to Tb magnetic atoms acting as impurities. Additionally, we observed that
the spectroscopic features vanished under magnetic field.


title:
Stellar Populations of Early-type Galaxies with Mid-Infrared Excess
  Emission

abstract:
  We present a stellar population analysis of quiescent (without H$\alpha$
emission) and bright ($M_{r}$ $<$ $-$21.5) early-type galaxies (ETGs) with
recent star formation. The ETGs are selected from a spectroscopic sample of
SDSS galaxies at 0.04 $<$ $z$ $<$ 0.11 with {\it WISE} mid-infrared (IR) and
{\it GALEX} near-ultraviolet (UV) emissions. We stack the optical spectra of
ETGs with different amounts of mid-IR and near-UV excess emissions to measure
the strength of 4000 \AA{} break $D_{n}$4000 and the width of Balmer absorption
line H$\delta_{A}$ that are indicative of recent ($\sim$1 Gyr) star formation
activity. The {\it WISE} [3.4]$-$[12] colors show stronger correlations with
the spectral features than NUV$-r$ colors. We fit to the stacked spectra with a
spectral fitting code, STARLIGHT, and find that the mass fraction of young
($\leq$1 Gyr) and intermediate-age ($\sim$1$-$5 Gyr) stars in the ETGs with
mid-IR excess emission is $\sim$4$-$11\%, depending on the template spectrum
used for the fit. These results show that the ETGs with mid-IR excess emission
have experienced star formation within the last 1$-$5 Gyr and that the mid-IR
emission is a useful diagnostic tool for probing recent star formation activity
in ETGs.


title:
Stochastic Particle Acceleration in Turbulence Generated by the
  Magnetorotational Instability

abstract:
  We investigate stochastic particle acceleration in accretion flows. It is
believed that the magnetorotational instability (MRI) generates turbulence
inside accretion flows and that cosmic rays (CRs) are accelerated by the
turbulence. We calculate equations of motion for CRs in the turbulent fields
generated by MRI with the shearing box approximation without back reaction to
the field. The results show that the CRs randomly gain or lose their energies
through the interaction with the turbulent fields. The CRs diffuse in the
configuration space anisotropically: The diffusion coefficient in direction of
the unperturbed flow is about twenty times higher than the Bohm coefficient,
while those in the other directions are only a few times higher than the Bohm.
The momentum distribution is isotropic, and its evolution can be described by
the diffusion equation in momentum space where the diffusion coefficient is a
power-law function of the CR momentum. We show that the shear acceleration
efficiently works for energetic particles. We also cautiously note that in the
shearing box approximation, particles that cross the simulation box many times
along the radial direction suffer unphysical runaway acceleration by the
Lorentz transformation, which needs to be taken with special care.


title: The Lp Minkowski problem for polytopes for negative p

abstract:
  Existence of solutions to the Lp Minkowski problem is proved for all p less
than 0. For the cirtical case of p=-n, which is known as the centro-affine
Minkowski problem, this paper contains the main result in [71] as a special
case.


title:
Local-move-identities for the Z[t,t^{-1}]-Alexander polynomials of
  2-links, the alinking number, and high dimensional analogues

abstract:
  A well-known identity (Alex+) - (Alex-)=(t^{1/2}-t^{-1/2}) (Alex0) holds for
three 1-links L+, L-, and L0 which satisfy a famous local-move-relation.
  We prove a new local-move-identity for the Z[t,t^{-1}]-Alexander polynomials
of 2-links, which is a 2-dimensional analogue of the 1-dimensional one. In the
1-dimensional link case there is a well-known relation between the
Alexander-Conway polynomial and the linking number. As its 2-dimensional
analogue, we find a relation between the Z[t,t^{-1}]-Alexander polynomials of
2-links and the alinking number of 2-links. We show high dimensional analogues
of these results. Furthermore we prove that in the 2-dimensional case we cannot
normalize the Z[t,t^{-1}]-Alexander polynomials to be compatible with our
identity but that in a high-dimensional case we can do that to be compatible
with our new identity.


title: Recurrent Neural Network Grammars

abstract:
  We introduce recurrent neural network grammars, probabilistic models of
sentences with explicit phrase structure. We explain efficient inference
procedures that allow application to both parsing and language modeling.
Experiments show that they provide better parsing in English than any single
previously published supervised generative model and better language modeling
than state-of-the-art sequential RNNs in English and Chinese.


title: Probing quantum grav ity effects with ion trap

abstract:
  The existence of minimal length scale has motivated the proposal of
generalized uncertainty principle, which provides a potential routine to probe
quantum gravitational effects in low-energy quantum mechanics experiment.
Hitherto, the tabletop experiment of testing deviations from ordinary quantum
mechanics are mostly based on microscopic objects. However, the feasibility of
these studies are challenged by the recent study of spacetime quantization for
composite macroscopic body. In this paper, we propose a scheme to probe quantum
gravity effects by revealing the deviations from predictions of Heisenberg
uncertainty principle. Our scheme focus on manipulating the interaction
sequences between external laser fields and a single trapped ion to seek
evidence of spacetime quantization, therefore reduce the complicity induced by
large bodies to some extent. The relevant study for microscopic particles is
crucial considering the lack of satisfactory theories regarding basic
properties for multi-particles in the framework of quantum gravity. Meanwhile,
we are managed to set a new upper limit for deformation parameter.