title: p-adic deformation of graph cycles

abstract:
  In this paper, we show that the infinitesimal Torelli theorem implies the
existence of deformations of automorphisms. In the first part, we use Hodge
theory and deformation theory to study the deformations of automorphisms of
complex projective manifolds. In the second part, we use crystalline cohomology
to explore the p-adic analogues of the first part, which generalizes a result
of Berthelot and Ogus. The study of the deformations of automorphisms also
provides criterions characterizing when the action of the automorphism group of
a variety on its cohomology is faithful.


title: Hopf algebroids with balancing subalgebra

abstract:
  Recently, S. Meljanac proposed a construction of a class of examples of an
algebraic structure with properties very close to the Hopf algebroids $H$ over
a noncommutative base $A$ of other authors. His examples come along with a
subalgebra $\mathcal{B}$ of $H\otimes H$, here called the balancing subalgebra,
which contains the image of the coproduct and such that the intersection of
$\mathcal{B}$ with the kernel of the projection $H\otimes H\to H\otimes_A H$ is
a two-sided ideal in $\mathcal{B}$ which is moreover well behaved with respect
to the antipode. We propose a set of abstract axioms covering this construction
and make a detailed comparison to the Hopf algebroids of Lu. We prove that
every scalar extension Hopf algebroid can be cast into this new set of axioms.
We present an observation by G. B\"ohm that the Hopf algebroids constructed
from weak Hopf algebras fit into our framework as well. At the end we discuss
the change of balancing subalgebra under Drinfeld-Xu procedure of twisting of
associative bialgebroids by invertible 2-cocycles.


title:
Higher order moments of net-charge and multiplicity distributions in p+p
  interactions at SPS energies from NA61/SHINE

abstract:
  NA61/SHINE at the CERN SPS is a fixed-target experiment pursuing a rich
physics program including measurements for heavy ion, neutrino and cosmic ray
physics. The main goal of the ion program is to study the properties of the
onset of deconfinement and to search for the signatures of the critical point.
A specific property of the critical point, the increase in the correlation
length, makes fluctuations its basic signal. Higher order moments of suitable
observables are of special interest as they are more sensitive to the
correlation length than typically studied second order moments. In this
contribution preliminary results on higher order fluctuations of negatively
charged hadron multiplicity and net-charge in p+p interactions are shown. The
new data are compared with model predictions.


title:
Variational approximation of functionals defined on 1-dimensional
  connected sets: the planar case

abstract:
  In this paper we consider variational problems involving 1-dimensional
connected sets in the Euclidean plane, such as the classical Steiner tree
problem and the irrigation (Gilbert-Steiner) problem. We relate them to optimal
partition problems and provide a variational approximation through
Modica-Mortola type energies proving a $\Gamma$-convergence result. We also
introduce a suitable convex relaxation and develop the corresponding numerical
implementations. The proposed methods are quite general and the results we
obtain can be extended to $n$-dimensional Euclidean space or to more general
manifold ambients, as shown in the companion paper [11].


title: Possible dark matter annihilation signal in the AMS-02 antiproton data

abstract:
  Using the latest AMS-02 cosmic ray antiproton flux data, we search for
potential dark matter annihilation signal. The background parameters about the
propagation, source injection, and solar modulation are not assumed {\it a
priori}, but based on the results inferred from the recent B/C ratio and proton
data measurements instead. The possible dark matter signal is incorporated into
the model self-consistently under a Bayesian framework. Compared with the
astrophysical background only hypothesis, we find that a dark matter signal is
favored. The rest mass of the dark matter particles is $\sim 20-80$ GeV and the
velocity-averaged hadronic annihilation cross section is about $(0.2-5)\times
10^{-26}$ cm$^{3}$s$^{-1}$, in agreement with that needed to account for the
Galactic center GeV excess and/or the weak GeV emission from dwarf spheroidal
galaxies Reticulum 2 and Tucana III. Tight constraints on the dark matter
annihilation models are also set in a wide mass region.


title: Multi-Soft gluon limits and extended current algebras at null-infinity

abstract:
  In this note we consider aspects of the current algebra interpretation of
multi-soft limits of tree-level gluon scattering amplitudes in four dimensions.
Building on the relation between a positive helicity gluon soft-limit and the
Ward identity for a level-zero Kac-Moody current, we use the double-soft limit
to define the Sugawara energy-momentum tensor and, by using the triple- and
quadruple-soft limits, show that it satisfies the correct OPEs for a CFT. We
study the resulting Knizhnik-Zamolodchikov equations and show that they hold
for positive helicity gluons in MHV amplitudes. Turning to the sub-leading
soft-terms we define a one-parameter family of currents whose Ward identities
correspond to the universal tree-level sub-leading soft-behaviour. We compute
the algebra of these currents formed with the leading currents and amongst
themselves. Finally, by parameterising the ambiguity in the double-soft limit
for mixed helicities, we introduce a non-trivial OPE between the holomorphic
and anti-holomorphic currents and study some of its implications.


title: On the algebraic stringy Euler number

abstract:
  We are interested in stringy invariants of singular projective algebraic
varieties satisfying a strict monotonicity with respect to elementary
birational modifications in the Mori program. We conjecture that the algebraic
stringy Euler number is one of such invariants. In the present paper, we prove
this conjecture for varieties having an action of a connected algebraic group G
and admitting equivariant desingularizations with only finitely many G-orbits.
In particular, we prove our conjecture for arbitrary projective spherical
varieties.


title:
On the effect of excited states in lattice calculations of the nucleon
  axial charge

abstract:
  Excited-state contamination is one of the dominant uncertainties in lattice
calculations of the nucleon axial-charge, $g_A$. Recently published results in
leading-order chiral perturbation theory (ChPT) predict the excited-state
contamination to be independent of the nucleon interpolator and positive.
However, empirical results from numerical lattice calculations show negative
contamination (downward curvature), indicating that present-day calculations
are not in the regime where the leading-order ChPT predictions apply. In this
paper we show that, under plausible assumptions, one can reproduce the behavior
of lattice correlators by taking into account final-state $N \pi$ interactions,
in particular the effect of the Roper resonance, and by postulating a sign
change in the infinite-volume $N \to N \pi$ axial-vector transition amplitude.


title:
Simple graded rings, non-associative crossed products and Cayley-Dickson
  doublings

abstract:
  We show that if a non-associative unital ring is graded by a hypercentral
group, then the ring is simple if and only if it is graded simple and the
center of the ring is a field. Thereby, we extend a result by Jespers to a
non-associative setting. By applying this result to non-associative crossed
products, we obtain non-associative analogues of results by Bell, Jordan and
Voskoglou. We also apply our result to Cayley-Dickson doublings, thereby
obtaining a new proof of a classical result by McCrimmon.


title: Spatial heterodyne scanning laser confocal holographic microscopy

abstract:
  Scanning laser confocal holographic microscopy using a spatial heterodyne
detection method is presented. Spatial heterodyne detection technique employs a
Mach-Zehnder interferometer with the reference beam frequency shifted by two
acousto-optic modulators (AOM) relative to the object beam frequency. Different
from the traditional temporal heterodyne detection technique in which hundreds
temporal samples are taken at each scanning point to achieve the complex
signal, the spatial heterodyne detection technique generates spatial
interference fringes by use of a linear tempo-spatial relation provided by
galvanometer scanning in a typical line-scanning confocal microscope or for the
slow-scanning on one dimension in a point-scanning confocal microscope, thereby
significantly reducing sampling rate and increasing the signal to noise ratio
under the same illumination compared to the traditional temporal heterodyne
counterpart. The proposed spatial heterodyne detection scheme applies to both
line-scanning and point-scanning confocal microscopes. In this paper, we
present the mathematical principles of the spatial heterodyne detection method
and experimental schemes for both line-scanning and point-scanning confocal
microscopes. Computer experiments are provided to demonstrate the validity of
this idea. The presented spatial heterodyne scanning laser confocal holographic
microscope (SH-SLCHM) can obtain both amplitude and quantitative phase
information of the object field without a significant increase in complexity of
optical and electronic design on the basis of a traditional scanning laser
confocal microscope (SLCM). SH-SLCHM may find applications in optical
metrology, in-vivo tissue imaging, and ophthalmic imaging.


title: Using electric fields for pulse compression and group velocity control

abstract:
  In this article, we experimentally demonstrate a new way of controlling the
group velocity of an optical pulse by using a combination of spectral hole
burning, slow light effect and linear Stark effect in a rare-earth-ion-doped
crystal. The group velocity can be changed continuously by a factor of 20
without significant pulse distortion or absorption of the pulse energy. With a
similar technique, an optical pulse can also be compressed in time. Theoretical
simulations were developed to simulate the group velocity control and the pulse
compression processes. The group velocity as well as the pulse reshaping are
solely controlled by external voltages which makes it promising in quantum
information and quantum communication processes. It is also proposed that the
group velocity can be changed even more in an Er doped crystal while at the
same time having a transmission band matching the telecommunication wavelength.


title: Mobility of an axisymmetric particle near an elastic interface

abstract:
  Using a fully analytical theory, we compute the leading order corrections to
the translational, rotational and translation-rotation coupling mobilities of
an arbitrary axisymmetric particle immersed in a Newtonian fluid moving near an
elastic cell membrane that exhibits resistance towards stretching and bending.
The frequency-dependent mobility corrections are expressed as general relations
involving separately the particle's shape-dependent bulk mobility and the
shape-independent parameters such as the membrane-particle distance, the
particle orientation and the characteristic frequencies associated with
shearing and bending of the membrane. This makes the equations applicable to an
arbitrary-shaped axisymmetric particle provided that its bulk mobilities are
known, either analytically or numerically. For a spheroidal particle, these
general relations reduce to simple expressions in terms of the particle's
eccentricity. We find that the corrections to the translation-rotation coupling
mobility are primarily determined by bending, whereas shearing manifests itself
in a more pronounced way in the rotational mobility. We demonstrate the
validity of the analytical approximations by a detailed comparison with
boundary integral simulations of a truly extended spheroidal particle. They are
found to be in a good agreement over the whole range of applied frequencies.


title: Chiral Dark Sector

abstract:
  We present a simple and natural dark sector model in which dark matter
particles arise as composite states of hidden strong dynamics and their
stability is ensured by accidental symmetries. The model has only a few free
parameters. In particular, the gauge symmetry of the model forbids the masses
of dark quarks, and the confinement scale of the dynamics provides the unique
mass scale of the model. The gauge group contains an Abelian symmetry $U(1)_D$,
which couples the dark and standard model sectors through kinetic mixing. This
model, despite its simple structure, has rich and distinctive phenomenology. In
the case where the dark pion becomes massive due to $U(1)_D$ quantum
corrections, direct and indirect detection experiments can probe thermal relic
dark matter which is generically a mixture of the dark pion and the dark
baryon, and the Large Hadron Collider can discover the $U(1)_D$ gauge boson.
Alternatively, if the dark pion stays light due to a specific $U(1)_D$ charge
assignment of the dark quarks, then the dark pion constitutes dark radiation.
The signal of this radiation is highly correlated with that of dark baryons in
dark matter direct detection.


title: Axion-Assisted Production of Sterile Neutrino Dark Matter

abstract:
  Sterile neutrinos can be generated in the early universe through oscillations
with active neutrinos and represent a popular and well-studied candidate for
our universe's dark matter. Stringent constraints from X-ray and gamma-ray line
searches, however, have excluded the simplest of such models. In this letter,
we propose a novel alternative to the standard scenario in which the mixing
angle between the sterile and active neutrinos is a dynamical quantity, induced
through interactions with a light axion-like field. As the energy density of
the axion-like particles is diluted by Hubble expansion, the degree of mixing
is reduced at late times, suppressing the decay rate and easily alleviating any
tension with X-ray or gamma-ray constraints. We present a simple model which
illustrates the phenomenology of this scenario, and also describe a framework
in which the QCD axion is responsible for the production of sterile neutrinos
in the early universe.


title:
The unorthodox evolution of major merger remnants into star-forming
  spiral galaxies

abstract:
  Galaxy mergers are believed to play a key role in transforming star-forming
disk galaxies into quenched ellipticals. Most of our theoretical knowledge
about such morphological transformations does, however, rely on idealised
simulations where processes such as cooling of hot halo gas into the disk and
gas accretion in the post-merger phase are not treated in a self-consistent
cosmological fashion. In this paper we study the morphological evolution of the
stellar components of four major mergers occurring at z=0.5 in cosmological
hydrodynamical zoom-simulations. In all simulations the merger reduces the disk
mass-fraction, but all galaxies simulated at our highest resolution regrow a
significant disk by z=0 (with a disk fraction larger than 24%). For runs with
our default physics model, which includes galactic winds from star formation
and black hole feedback, none of the merger remnants are quenched, but in a set
of simulations with stronger black hole feedback we find that major mergers can
indeed quench galaxies. We conclude that major merger remnants commonly evolve
into star-forming disk galaxies, unless sufficiently strong AGN feedback
assists in the quenching of the remnant.


title:
The Multiple Young Stellar Objects of HBC 515: An X-ray and
  Millimeter-wave Imaging Study in (Pre-main Sequence) Diversity

abstract:
  We present Chandra X-ray Observatory and Submillimeter Array (SMA) imaging of
HBC 515, a system consisting of multiple young stellar objects (YSOs). The five
members of HBC 515 represent a remarkably diverse array of YSOs, ranging from
the low-mass Class I/II protostar HBC 515B, through Class II and transition
disk objects (HBC 515D and C, respectively), to the "diskless", intermediate-
mass, pre-main sequence binary HBC 515A. Our Chandra/ACIS imaging establishes
that all five components are X-ray sources, with HBC 515A - a
subarcsecond-separation binary that is partially resolved by Chandra - being
the dominant X-ray source. We detect an X-ray flare associated with HBC 515B.
In the SMA imaging, HBC 515B is detected as a strong 1.3 mm continuum emission
source; a second, weaker mm continuum source is coincident with the position of
the transition disk object HBC 515C. These results strongly support the
protostellar nature of HBC 515B, and firmly establish HBC 515A as a member of
the rare class of relatively massive, X-ray luminous "weak-lined T Tauri stars"
that are binaries and have shed their disks at very early stages of pre-MS
evolution. The coexistence of two such disparate objects within a single,
presumably coeval multiple YSO system highlights the influence of pre- MS star
mass, binarity, and X-ray luminosity in regulating the lifetimes of
circumstellar, planet-forming disks and the timescales of star-disk
interactions.


title:
On the metallicity dependance of the [Y/Mg] - age relation for solar
  type stars

abstract:
  Several recent studies of Solar twins in the Solar neighbourhood have shown a
tight correlation between various elemental abundances and age, in particular
[Y/Mg]. If this relation is real and valid for other types of stars as well as
elsewhere in the Galaxy it would provide a very powerful tool to derive ages of
stars without the need to resort to determining their masses (evolutionary
stage) very precisely. The method would also likely work if the stellar
parameters have relatively large errors. The studies presented in the recent
literature span a narrow range of [Fe/H]. By studying a larger sample of Solar
neighbourhood dwarfs with a much larger range in [Fe/H], we find that the
relation between [Y/Mg] and age depends on the [Fe/H] of the stars. Hence, it
appears that the [Y/Mg] - age relation is unique to Solar analogues.


title:
IMF and [Na/Fe] abundance ratios from optical and NIR Spectral Features
  in Early-type Galaxies

abstract:
  We present a joint analysis of the four most prominent sodium-sensitive
features (NaD, NaI8190, NaI1.14, and NaI2.21), in the optical and Near-Infrared
spectral range, of two nearby, massive (sigma~300km/s), early-type galaxies
(named XSG1 and XSG2). Our analysis relies on deep VLT/X-Shooter long-slit
spectra, along with newly developed stellar population models, allowing for
[Na/Fe] variations, up to 1.2dex, over a wide range of age, total metallicity,
and IMF slope. The new models show that the response of the Na-dependent
spectral indices to [Na/Fe] is stronger when the IMF is bottom heavier. For the
first time, we are able to match all four Na features in the central regions of
massive early-type galaxies, finding an overabundance of [Na/Fe], in the range
0.5-0.7dex, and a bottom-heavy IMF. Therefore, individual abundance variations
cannot be fully responsible for the trends of gravity-sensitive indices,
strengthening the case towards a non-universal IMF. Given current limitations
of theoretical atmosphere models, our [Na/Fe] estimates should be taken as
upper limits. For XSG1, where line strengths are measured out to 0.8Re, the
radial trend of [Na/Fe] is similar to [Mg/Fe] and [C/Fe], being constant out to
0.5Re, and decreasing by 0.2-0.3dex at 0.8Re, without any clear correlation
with local metallicity. Such a result seems to be in contrast with the
predicted increase of Na nucleosynthetic yields from AGB stars and TypeII SNe.
For XSG1, the Na-inferred IMF radial profile is consistent, within the errors,
with that derived from TiO features and the Wing-Ford band, presented in a
recent paper.


title:
The observed spatial distribution of matter on scales ranging from
  100kpc to 1Gpc is inconsistent with the standard dark-matter-based
  cosmological models

abstract:
  The spatial arrangement of galaxies (of satellites on a scale of 100kpc) as
well as their three-dimensional distribution in galaxy groups such as the Local
Group (on a scale of 1Mpc), the distribution of galaxies in the nearby volume
of galaxies (on a scale of 8Mpc) and in the nearby Universe (on a scale of
1Gpc) is considered. There is further evidence that the CMB shows
irregularities and for anisotropic cosmic expansion. The overall impression one
obtains, given the best data we have, is matter to be arranged as not expected
in the dark-matter based standard model of cosmology (SMoC). There appears to
be too much structure, regularity and organisation. Dynamical friction on the
dark matter halos is a strong direct test for the presence of dark matter
particles, but this process does not appear to be operative in the real
Universe. This evidence suggests strongly that dynamically relevant dark matter
does not exist and therefore cosmology remains largely not understood
theoretically. More-accepted awareness of this case would by itself constitute
a major advance in research providing fabulous opportunities for bright minds,
and the observational data strongly suggest that gravitation must be
effectively Milgromian, corresponding to a generalized Poisson equation in the
classical limit. Thus, physical cosmology offers a significant historically
relevant opportunity for ground-breaking work, at least for those daring to do
so.


title: Topological Exciton Bands in Moir\'e Heterojunctions

abstract:
  Moir\'e patterns are common in Van der Waals heterostructures and can be used
to apply periodic potentials to elementary excitations. We show that the
optical absorption spectrum of transition metal dichalcogenide bilayers is
profoundly altered by long period moir\'e patterns that introduce twist-angle
dependent satellite excitonic peaks. Topological exciton bands with non-zero
Chern numbers that support chiral excitonic edge states can be engineered by
combining three ingredients: i) the valley Berry phase induced by electron-hole
exchange interactions, ii) the moir\'e potential, and iii) the valley Zeeman
field.


title:
Spectroscopic confirmation of the dwarf spheroidal galaxy d0944+71 as a
  member of the M81 group of galaxies

abstract:
  We use Keck/DEIMOS spectroscopy to measure the first velocity and metallicity
of a dwarf spheroidal (dSph) galaxy beyond the Local Group using resolved
stars. Our target, d0944+71, is a faint dSph found in the halo of the massive
spiral galaxy M81 by Chiboucas et al. We coadd the spectra of 27 individual
stars and measure a heliocentric radial velocity of $-38\pm10$~km/s. This
velocity is consistent with d0944+71 being gravitationally bound to M81. We
coadd the spectra of the 23 stars that are consistent with being red giant
branch stars and measure an overall metallicity of ${\rm [Fe/H]}=-1.3 \pm 0.3$
based on the calcium triplet lines. This metallicity is consistent with
d0944+71 following the metallicity$-$luminosity relation for Local Group dSphs.
We investigate several potential sources of observational bias but find that
our sample of targeted stars is representative of the metallicity distribution
function of d0944+71 and any stellar contamination due to seeing effects is
negligible. The low ellipticity of the galaxy and its position in the
metallicity$-$luminosity relation suggest that d0944+71 has not been affected
by strong tidal stripping.


title: The Distance to M104

abstract:
  M104 (NGC 4594; the Sombrero galaxy) is a nearby, well-studied elliptical
galaxy included in scores of surveys focused on understanding the details of
galaxy evolution. Despite the importance of observations of M104, a consensus
distance has not yet been established. Here, we use newly obtained Hubble Space
Telescope optical imaging to measure the distance to M104 based on the tip of
the red giant branch method. Our measurement yields the distance to M104 to be
9.55 +/- 0.13 +/- 0.31 Mpc equivalent to a distance modulus of 29.90 +/- 0.03
+/- 0.07 mag. Our distance is an improvement over previous results as we use a
well-calibrated, stable distance indicator, precision photometry in a optimally
selected field of view, and a Bayesian Maximum Likelihood technique that
reduces measurement uncertainties. The most discrepant previous results are due
to Tully-Fisher method distances, which are likely inappropriate for M104 given
its peculiar morphology and structure. Our results are part of a larger program
to measure accurate distances to a sample of well-known spiral galaxies
(including M51, M74, and M63) using the tip of the red giant branch method.


title:
On the Medvedev-Scanlon Conjecture for Minimal Threefolds of
  Non-Negative Kodaira Dimension

abstract:
  Motivated by work of Zhang from the early `90s, Medvedev and Scanlon
formulated the following conjecture. Let $K$ be an algebraically closed field
of characteristic $0$ and let $X$ be a quasiprojective variety defined over $K$
endowed with a dominant rational self-map $\Phi$. Then there exists a point
$\alpha\in X(K)$ with Zariski dense orbit under $\Phi$ if and only if $\Phi$
preserves no nontrivial rational fibration, i.e., there exists no non-constant
rational function $f\in K(X)$ such that $\Phi^*(f)=f$. The Medvedev-Scanlon
conjecture holds when $K$ is uncountable. The case where $K$ is countable
(e.g., $K=\overline{\mathbb{Q}}$) is much more difficult; here the conjecture
has only been proved in a small number of special cases. In this paper we show
that the Medvedev-Scanlon conjecture holds for all varieties of positive
Kodaira dimension, and explore the case of Kodaira dimension $0$. Our results
are most complete in dimension $3$.


title:
HIghMass - High HI Mass, HI-Rich Galaxies at $z\sim0$: Combined HI and
  H$_2$ Observations

abstract:
  We present resolved HI and CO observations of three galaxies from the
HIghMass sample, a sample of HI-massive ($M_{HI} > 10^{10} M_\odot$), gas-rich
($M_{HI}$ in top $5\%$ for their $M_*$) galaxies identified in the ALFALFA
survey. Despite their high gas fractions, these are not low surface brightness
galaxies, and have typical specific star formation rates (SFR$/M_*$) for their
stellar masses. The three galaxies have normal star formation rates for their
HI masses, but unusually short star formation efficiency scale lengths,
indicating that the star formation bottleneck in these galaxies is in the
conversion of HI to H$_2$, not in converting H$_2$ to stars. In addition, their
dark matter spin parameters ($\lambda$) are above average, but not
exceptionally high, suggesting that their star formation has been suppressed
over cosmic time but are now becoming active, in agreement with prior H$\alpha$
observations.


title:
X-ray counterpart of gravitational waves due to binary neutron star
  mergers: light curves, luminosity functions, and event rate densities

abstract:
  Zhang (2013) proposed a type of GRB-less X-ray transient associated with
double neutron star (NS-NS) mergers under the conjecture of a rapidly-spinning
magnetar merger product with the line of sight off the short GRB jet. We
investigate possible light curves of these transients by considering different
observer's viewing angles. We perform Monte Carlo simulations to calculate the
peak luminosity function (LF) and event rate density of these X-ray transients.
By considering that a fraction of massive neutron stars may be supra-massive
and later collapse into black holes after spinning down, we investigate how the
predicted LF depends on the equation of state (EoS) of the central object and
the geometry of the system. In general, the LF can be fit by two log-normal
distributions peaking around $10^{46.4}$ and $10^{49.6}$ $\rm erg\,s^{-1}$,
corresponding to the trapped and free zones, respectively. For the majority of
the EoS models, the current non-detection is consistent with having a free zone
solid angle at most a few times of the solid angle of the short GRB jet. The
event rate density of these X-ray transients is around a few tens of $\rm
Gpc^{-3}yr^{-1}$ for luminosity above $10^{45}$ $\rm erg\,s^{-1}$. We predict
that future X-ray telescopes (such as Einstein Probe) with sensitivity $\sim
10^{-11}$ $\rm erg\,s^{-1}\,cm^{-2}$ would detect as many as several tens of
such transients per year per steradian. Within 200 Mpc, the aLIGO average range
for NS-NS mergers, the estimated event rate of these transients is about 1
transient per year all sky.


title: Radio observations of the tidal disruption event XMMSL1 J0740$-$85

abstract:
  We present radio observations of the tidal disruption event candidate (TDE)
XMMSL1 J0740$-$85 spanning 592 to 875 d post X-ray discovery. We detect radio
emission that fades from an initial peak flux density at 1.6 GHz of $1.19\pm
0.06$ mJy to $0.65\pm 0.06$ mJy suggesting an association with the TDE. This
makes XMMSL1 J0740$-$85 at $d=75$ Mpc the nearest TDE with detected radio
emission to date and only the fifth TDE with radio emission overall. The
observed radio luminosity rules out a powerful relativistic jet like that seen
in the relativistic TDE Swift J1644+57. Instead we infer from an equipartition
analysis that the radio emission most likely arises from a non-relativistic
outflow similar to that seen in the nearby TDE ASASSN-14li, with a velocity of
about $10^4$ km s$^{-1}$ and a kinetic energy of about $10^{48}$ erg, expanding
into a medium with a density of about $10^2$ cm$^{-3}$. Alternatively, the
radio emission could arise from a weak initially-relativistic but decelerated
jet with an energy of $\sim 2\times 10^{50}$ erg, or (for an extreme disruption
geometry) from the unbound debris. The radio data for XMMSL1 J0740$-$85
continues to support the previous suggestion of a bimodal distribution of
common non-relativistic isotropic outflows and rare relativistic jets in TDEs
(in analogy with the relation between Type Ib/c supernovae and long-duration
gamma-ray bursts). The radio data also provide a new measurement of the
circumnuclear density on a sub-parsec scale around an extragalactic
supermassive black hole.


title: The grounded Martin's axiom

abstract:
  We introduce a variant of Martin's axiom, called the grounded Martin's axiom,
which asserts that the universe is a ccc forcing extension in which Martin's
axiom holds for posets in the ground model. This principle already implies
several of the combinatorial consequences of Martin's axiom. The new axiom is
shown to be consistent with the failure of Martin's axiom and a singular
continuum. We prove that the grounded Martin's axiom is preserved in a strong
way when adding a Cohen real and that adding a random real to a model of
Martin's axiom preserves the grounded version (even though it destroys Martin's
axiom itself). We also consider the analogous variant of the proper forcing
axiom.


title:
High Dimensional Uncertainty Quantification for an Electrothermal Field
  Problem using Stochastic Collocation on Sparse Grids and Tensor Train
  Decompositions

abstract:
  The temperature developed in bondwires of integrated circuits (ICs) is a
possible source of malfunction, and has to be taken into account during the
design phase of an IC. Due to manufacturing tolerances, a bondwire's
geometrical characteristics are uncertain parameters, and as such their impact
has to be examined with the use of uncertainty quantification (UQ) methods.
Sampling methods, like the Monte Carlo (MC), converge slowly, while efficient
alternatives scale badly with respect to the number of considered
uncertainties. Possible remedies to this, so-called, curse of dimensionality
are sought in the application of stochastic collocation (SC) on sparse grids
(SGs) and of the recently emerged low-rank tensor decomposition methods, with
emphasis on the tensor train (TT) decomposition.


title:
Surface-Plasmon-Polariton Laser based on an Open-Cavity Fabry-Perot
  Resonator

abstract:
  Recent years have witnessed growing interest in the development of
small-footprint lasers for potential applications in small-volume sensing and
on-chip optical communications. Surface-plasmons, electromagnetic modes
evanescently confined to metal-dielectric interfaces, offer an effective route
to achieving lasing at nanometer-scale dimensions when resonantly amplified in
contact with a gain-medium. Here, we achieve visible frequency ultra-narrow
linewidth lasing at room-temperature by leveraging surface plasmons propagating
in an open Fabry-Perot cavity formed by a flat metal surface coated with a
subwavelength-thick layer of optically-pumped gain medium and orthogonally
bound by a pair of flat metal sidewalls. Low perturbation
transmission-configuration sampling of the lasing plasmon mode is achieved via
an evanescently coupled recessed nanoslit, opening the way to
high-figure-of-merit refractive-index sensing of analytes interacting with the
open cavity.


title:
Status of the Schwarzchild-Couder Medium-Sized Telescope for the
  Cherenkov Telescope Array

abstract:
  The Cherenkov Telescope Array (CTA) is planned to be the next-generation
very-high-energy (VHE; E > 100 GeV) gamma-ray observatory. It is anticipated
that CTA will improve upon the sensitivity of the current generation of VHE
experiments, such as VERITAS, HESS and MAGIC, by an order of magnitude. CTA is
planned to consist of two graded arrays of Cherenkov telescopes with three
primary-mirror sizes. A proof-of-concept telescope, based on the dual-mirror
Schwarzchild-Couder design, is being constructed on the VERITAS site at the
F.L. Whipple Observatory in southern Arizona, USA, and is a candidate design
for the medium-sized telescopes. The construction of the telescope will be
completed in early 2017, and the status of this project is presented here.


title:
Scroll-wave dynamics in the presence of ionic and conduction
  inhomogeneities in an anatomically realistic mathematical model for the pig
  heart

abstract:
  Nonlinear waves of the reaction-diffusion (RD) type occur in many biophysical
systems, including the heart, where they initiate cardiac contraction. Such
waves can form vortices called scroll waves, which result in the onset of
life-threatening cardiac arrhythmias. The dynamics of scroll waves is affected
by the presence of inhomogeneities, which, in a very general way, can be of
\textit{(i)} ionic type, i.e., they affect the reaction part, or \textit{(ii)}
conduction type, i.e., they affect the diffusion part of an RD equation. We
demostrate, for the first time, by using a state-of-the-art, anatomically
realistic model of the pig heart, how differences in the geometrical and
biophysical nature of such inhomogeneities can influence scroll-wave dynamics
in different ways. Our study reveals that conduction-type inhomogeneities
become increasingly important at small length scales, i.e., in the case of
multiple, randomly distributed, obstacles in space at the cellular scale
($0.2-0.4{\rm mm}$). Such configurations can lead to scroll-wave break up. In
contrast, ionic inhomogeneities, affect scroll-wave dynamics significantly at
large length scales, when these inhomogeneities are localized in space at the
tissue level ($5-10$ mm). In such configurations, these inhomogeneities can (a)
attract scroll waves, by pinning them to the heterogeneity, or (b) lead to
scroll-wave breakup.


title: Young Stars with SALT

abstract:
  We present a spectroscopic and kinematic analysis of 79 nearby M dwarfs in 77
systems. All are low-proper-motion southern hemisphere objects and were
identified in a nearby star survey with a demonstrated sensitivity to young
stars. Using low-resolution optical spectroscopy from the Red Side Spectrograph
(RSS) on the South African Large Telescope (SALT), we have determined radial
velocities, H-alpha, Lithium 6708\AA, and Potassium 7699\AA~equivalent widths
linked to age and activity, and spectral types for all our targets. Combined
with astrometric information from literature sources, we identify 44 young
stars. Eighteen are previously known members of moving groups within 100
parsecs of the Sun. Twelve are new members, including one member of the TW
Hydra moving group, one member of the 32 Orionis moving group, nine members of
Tucana-Horologium, one member of Argus, and two new members of AB Doradus. We
also find fourteen young star systems that are not members of any known groups.
The remaining 33 star systems do not appear to be young. This appears to be
evidence of a new population of nearby young stars not related to the known
nearby young moving groups.


title: Gr\"uss type inequalities for positive linear maps on $C^*$-algebras

abstract:
  Let $\mathcal{A}$ and $\mathcal{B}$ be two unital $C^*$-algebras and let for
$C\in\mathcal{A},\ \Gamma_C=\{\gamma \in \mathbb{C} : \|C-\gamma
I\|=\inf_{\alpha\in \mathbb{C}} \|C-\alpha I\|\}$. We prove that if $\Phi
:\mathcal{A} \longrightarrow \mathcal{B}$ is a unital positive linear map, then
\begin{eqnarray*} \big|\Phi(AB)-\Phi(A)\Phi(B)\big| \leq \big\|\Phi(|A^*-\zeta
I|^2)\big\|^\frac{1}{2} \big[\Phi(|B-\xi I|^2)\big]^\frac{1}{2} \end{eqnarray*}
for all $A,B\in\mathcal{A}, \zeta \in \Gamma_A$ and $\xi\in\Gamma_B.$\\ In
addition, we show that if $(\mathcal{A},\tau)$ is a noncommutative probability
space and $T \in \mathcal{A}$ is a density operator, then \begin{eqnarray*} \ \
\big|\tau(TAB)-\tau(TA)\tau(TB)\big|\leq \|A-\zeta I\|_p\|B-\xi I\|_q\|T\|_r \
\ (p,q\geq 4, r\geq 2) \end{eqnarray*} and \begin{eqnarray*}
\big|\tau(TAB)-\tau(TA)\tau(TB)\big|\leq \|A-\zeta I\|_p\|B-\xi I\|_q\|T\| \ \
\ \ (p,q\geq 2)\ \ \ \ \ \end{eqnarray*} for every $A,B \in \mathcal{A}$ and
$\zeta \in \Gamma_A,\xi \in \Gamma_B$. Our results generalize the corresponding
results for matrices to operators on spaces of arbitrary dimension.


title:
Unitarily invariant norm inequalities for elementary operators involving
  $G_{1}$ operators

abstract:
  In this paper, motivated by perturbation theory of operators, we present some
upper bounds for $|||f(A)Xg(B)+ X|||$ in terms of $|||\,|AXB|+|X|\,|||$ and
$|||f(A)Xg(B)- X|||$ in terms of $|||\,|AX|+|XB|\,|||$, where $A, B$ are
$G_{1}$ operators, $|||\cdot|||$ is a unitarily invariant norm and $f, g$ are
certain analytic functions. Further, we find some new upper bounds for the the
Schatten $2$-norm of $f(A)X\pm Xg(B)$. Several special cases are discussed as
well.


title: Systole of congruence coverings of arithmetic hyperbolic manifolds

abstract:
  In this paper we prove that, for any arithmetic hyperbolic $n$-manifold $M$
of the first type, the systole of most of the principal congruence coverings
$M_{I}$ satisfy $$sys_{1}(M_{I})\geq \frac{8}{n(n+1)}\log(vol(M_{I}))-c,$$
where $c$ is a constant independent of $I$. This generalizes previous work of
Buser and Sarnak, and Katz, Schaps and Vishne in dimension 2 and 3. As
applications, we obtain explicit estimates for systolic genus of hyperbolic
manifolds studied by Belolipetsky and the distance of homological codes
constructed by Guth and Lubotzky. In an appendix together with Cayo D\'oria we
prove that the constant $\frac{8}{n(n+1)}$ is sharp.


title: Preconditioning via Diagonal Scaling

abstract:
  Interior point methods solve small to medium sized problems to high accuracy
in a reasonable amount of time. However, for larger problems as well as
stochastic problems, one needs to use first-order methods such as stochastic
gradient descent (SGD), the alternating direction method of multipliers (ADMM),
and conjugate gradient (CG) in order to attain a modest accuracy in a
reasonable number of iterations. In this report, we first discuss heuristics
for diagonal scaling. Next, we motivate preconditioning by an example, and then
we study preconditioning for a specific splitting form in ADMM called graph
projection splitting. Finally we examine the performance of our methods by some
numerical examples.


title: Dipole modes with depressed amplitudes in red giants are mixed modes

abstract:
  Seismic observations have shown that a number of evolved stars exhibit
low-amplitude dipole modes, which are referred to as depressed modes. Recently,
these low amplitudes have been attributed to the presence of a strong magnetic
field in the stellar core of those stars.
  We intend to study the properties of depressed modes in evolved stars, which
is a necessary condition before concluding on the physical nature of the
mechanism responsible for the reduction of the dipole mode amplitudes.
  We perform a thorough characterization of the global seismic parameters of
depressed dipole modes and show that these modes have a mixed character. The
observation of stars showing dipole mixed modes that are depressed is
especially useful for deriving model-independent conclusions on the dipole mode
damping.
  Observations prove that depressed dipole modes in red giants are not pure
pressure modes but mixed modes. This result invalidates the hypothesis that the
depressed dipole modes result from the suppression of the oscillation in the
radiative core of the stars. Observations also show that, except for the
visibility, the seismic properties of the stars with depressed modes are
equivalent to those of normal stars.
  The mixed nature of the depressed modes in red giants and their unperturbed
global seismic parameters carry strong constraints on the physical mechanism
responsible for the damping of the oscillation in the core. This mechanism is
able to damp the oscillation in the core but cannot fully suppress it.
Moreover, it cannot modify the radiative cavity probed by the gravity component
of the mixed modes. The recent mechanism involving high magnetic field proposed
for explaining depressed modes is not compliant with the observations and
cannot be used to infer the strength and the prevalence of high magnetic fields
in red giants.


title: The Tur\'an Polytope

abstract:
  The Tur\'an hypergraph problem asks to find the maximum number of $r$-edges
in a $r$-uniform hypergraph on $n$ vertices that does not contain a clique of
size $a$. When $r=2$, i.e., for graphs, the answer is well-known and can be
found in Tur\'an's theorem. However, when $r\geq 3$, the problem remains open.
We model the problem as an integer program and call the underlying polytope the
Tur\'an polytope. We draw parallels between the latter and the stable set
polytope: we show that generalized and transformed versions of the web and
wheel inequalities are also facet-defining for the Tur\'an polytope. We also
show clique inequalities and what we call doubling inequalities are
facet-defining when $r=2$. These facets lead to a simple new polyhedral proof
of Tur\'an's theorem.


title:
Generalized parafermions and non-local Josephson effect in multi-layer
  systems

abstract:
  We theoretically investigate the effects of backscattering and
superconducting proximity terms between the edges of two multi-layer fractional
quantum Hall (FQH) systems. While the different layers are strongly
interacting, we assume that tunneling between them is absent. Studying the
boundaries between regions gapped by the two mechanisms in an $N$-layer system,
we find $N$ localized zero-mode operators realizing a generalized parafermionic
algebra. We further propose an experiment capable of probing imprints of the
generalized parafermionic bound states. This is done by coupling different
superconducting contacts to different layers, and examining the periodicity of
the Josephson effect as a function of the various relative superconducting
phases. Remarkably, even if we apply a phase difference between the
superconductors in one layer, we induce a Josephson current at the other layers
due to inter-layer interactions. Furthermore, while the Josephson effect is
commonly used to probe only charged degrees of freedom, the possibility of
independently controlling the superconducting phase differences between the
layers allows us to find imprints of the neutral modes of the underlying
multi-layer system. In particular, we propose two configurations, one of which
is capable of isolating the signal associated with the charge modes, while the
other probes the neutral modes.


title: A compact neutron scatter camera for field deployment

abstract:
  We describe a very compact (0.9 m high, 0.4 m diameter, 40 kg) battery
operable neutron scatter camera designed for field deployment. Unlike most
other systems, the configuration of the sixteen liquid-scintillator detection
cells are arranged to provide omnidirectional (4{\pi}) imaging with sensitivity
comparable to a conventional two-plane system. Although designed primarily to
operate as a neutron scatter camera for localizing energetic neutron sources,
it also functions as a Compton camera for localizing gamma sources. In addition
to describing the radionuclide source localization capabilities of this system,
we demonstrate how it provides neutron spectra that can distinguish plutonium
metal from plutonium oxide sources, in addition to the easier task of
distinguishing AmBe from fission sources.


title:
The COSINUS project - a NaI-based cryogenic calorimeter for direct dark
  matter detection

abstract:
  At present the results in the field of direct dark matter search are in
tension: the positive claim of DAMA/LIBRA versus null results from other
experiments. However, the comparison of the results of different experiments
involves model dependencies, in particular because of the different target
materials in use. The COSINUS R&D project aims to operate NaI as a cryogenic
calorimeter. Such a detector would not only allow for a direct comparison to
DAMA/LIBRA, but would also provide a low(er) nuclear recoil threshold and
particle discrimination.


title: High-redshift major mergers weakly enhance star formation

abstract:
  Galaxy mergers are believed to trigger strong starbursts. This is well
assessed by observations in the local Universe. However the efficiency of this
mechanism has poorly been tested so far for high redshift, actively star
forming, galaxies. We present a suite of pc-resolution hydrodynamical numerical
simulations to compare the star formation process along a merging sequence of
high and low z galaxies, by varying the gas mass fraction between the two
models. We show that, for the same orbit, high-redshift gas-rich mergers are
less efficient than low-redshift ones at producing starbursts: the star
formation rate excess induced by the merger and its duration are both around 10
times lower than in the low gas fraction case. The mechanisms that account for
the star formation triggering at low redshift - the increased compressive
turbulence, gas fragmentation, and central gas inflows - are only mildly, if
not at all, enhanced for high gas fraction galaxy encounters. Furthermore, we
show that the strong stellar feedback from the initially high star formation
rate in high redshift galaxies does not prevent an increase of the star
formation during the merger. Our results are consistent with the observed
increase of the number of major mergers with increasing redshift being faster
than the respective increase in the number of starburst galaxies.


title:
Modeling real phononic crystals via the weighted relaxed micromorphic
  model with free and gradient micro-inertia

abstract:
  In this paper the relaxed micromorphic continuum model with weighted free and
gradient micro-inertia is used to describe the dynamical behavior of a real
two-dimensional phononic crystal for a wide range of wavelengths. In
particular, a periodic structure with specific micro-structural topology and
mechanical properties, capable of opening a phononic band-gap, is chosen with
the criterion of showing a low degree of anisotropy (the band-gap is almost
independent of the direction of propagation of the traveling wave). A Bloch
wave analysis is performed to obtain the dispersion curves and the
corresponding vibrational modes of the periodic structure. A linear-elastic,
isotropic, relaxed micromorphic model including both a free micro-inertia
(related to free vibrations of the microstructures) and a gradient
micro-inertia (related to the motions of the microstructure which are coupled
to the macro-deformation of the unit cell) is introduced and particularized to
the case of plane wave propagation. The parameters of the relaxed model, which
are independent of frequency, are then calibrated on the dispersion curves of
the phononic crystal showing an excellent agreement in terms of both dispersion
curves and vibrational modes. Almost all the homogenized elastic parameters of
the relaxed micromorphic model result to be determined. This opens the way to
the design of morphologically complex meta-structures which make use of the
chosen phononic structure as the basic building block and which preserve its
ability of "stopping" elastic wave propagation at the scale of the structure.


title:
Pseudo-invariants causing inverse energy cascades in three-dimensional
  turbulence

abstract:
  Three-dimensional (3D) turbulence is characterized by a dual forward cascade
of both kinetic energy and helicity, a second inviscid flow invariant, from the
integral scale of motion to the viscous dissipative scale. In helical flows,
however, such as strongly rotating flows with broken mirror symmetry, an
inverse energy cascade can be observed analogous to that of two-dimensional
turbulence (2D) where a second positive-definite flow invariant, enstrophy,
unlike helicity in 3D, effectively blocks the forward cascade of energy. In the
spectral-helical decomposition of the Navier-Stokes equation it has previously
been show that a subset of three-wave (triad) interactions conserve helicity in
3D in a fashion similar to enstrophy in 2D, thus leading to a 2D-like inverse
energy cascade in 3D. In this work, we show both theoretically and numerically
that an additional subset of interactions exist conserving a new
pseudo-invariant in addition to energy and helicity, which contributes either
to a forward or inverse energy cascade depending on the specific triad
interaction geometry.


title: From ordered semigroups to ordered hypersemigroups

abstract:
  We wrote this paper as an example to show the way we pass from ordered
semigroups to ordered hypersemigroups.


title: Black Hole Solutions in Rastall Theory

abstract:
  The Reissner-Nordstr\"om black hole solution in a generic cosmological
constant background in the the context of Rastall gravity is obtained. It is
shown that the cosmological constant arises naturally from the consistency of
the non-vacuum field equations of the Rastall theory for a spherical symmetric
spacetime, rather than its {\it ad-hoc} introduction in the usual Einstein and
Einstein-Maxwell field equations. The usual Reissner-Nordstr\"om, Schwarzschild
and Schwarzschild-(anti)de Sitter black hole solutions in the framework of this
theory are also addressed as the special independent subclasses of the obtained
general solution.


title:
Minkowski Momentum Resulting from a Vacuum-Medium Mapping Procedure, and
  a Brief Review of Minkowski Momentum Experiments

abstract:
  A discussion is given on the interpretation and physical importance of the
Minkowski momentum in macroscopic electrodynamics (essential for the
Abraham-Minkowski problem). We focus on the following two facets: (1) Adopting
a simple dielectric model where the refractive index $n$ is constant, we
demonstrate by means of a mapping procedure how the electromagnetic field in a
medium can be mapped into a corresponding field in vacuum. This mapping was
presented many years ago [I. Brevik and B. Lautrup, Mat. Fys. Medd. Dan. Vid.
Selsk {\bf 38}(1), 1 (1970)], but is apparently not well known. A
characteristic property of this procedure is that it shows how natural the
Minkowski energy-momentum tensor fits into the canonical formalism. Especially
the spacelike character of the electromagnetic total four-momentum for a
radiation field (implying negative electromagnetic energy in some inertial
frames), so strikingly demonstrated in the Cherenkov effect, is worth
attention. (2) Our second objective is to give a critical analysis of some
recent experiments on electromagnetic momentum. Care must here be taken in the
interpretations: it is easy to be misled and conclude that an experiment is
important for the energy-momentum problem, while what is demonstrated
experimentally is merely the action of the Abraham-Minkowski force acting in
surface layers or inhomogeneous regions. The Abraham-Minkowski force is common
for the two energy-momentum tensors and carries no information about field
momentum. As a final item, we propose an experiment that might show the
existence of the Abraham force at high frequencies. This would eventually be a
welcome optical analogue to the classic low-frequency 1975 Lahoz-Walker
experiment.


title: A method for obtaining Fibonacci identities

abstract:
  For the Lucas sequence $\{U_{k}(P,Q)\}$ we discuss the identities such as the
well-known Fibonacci identities. We also propose a method for obtaining
identities involving recurrence sequences. With the help of which we find an
interpolating type identity for second order linear recurrences.


title:
On the Cauchy problem for microlocally symmetrizable hyperbolic systems
  with log-Lipschitz coefficients

abstract:
  The present paper concerns the well-posedness of the Cauchy problem for
microlocally symmetrizable hyperbolic systems whose coefficients and
symmetrizer are log-Lipschitz continuous, uniformly in time and space
variables. For the global in space problem we establish energy estimates with
finite loss of derivatives, which is linearly increasing in time. This implies
well-posedness in $H^\infty$, if the coefficients enjoy enough smoothness in
$x$. From this result, by standard arguments (i.e. extension and
convexification) we deduce also local existence and uniqueness. A huge part of
the analysis is devoted to give an appropriate sense to the Cauchy problem,
which is not evident a priori in our setting, due to the very low regularity of
coefficients and solutions.


title: Highlights from the VERITAS AGN Observation Program

abstract:
  The VERITAS array of four 12-m imaging atmospheric-Cherenkov telescopes began
full-scale operations in 2007, and is one of the world's most sensitive
detectors of astrophysical very high energy (VHE; E>100 GeV) gamma rays.
Observations of active galactic nuclei (AGN) are a major focus of the VERITAS
Collaboration, and more than 60 AGN, primarily blazars, are known to emit VHE
photons. Approximately 4000 hours have been devoted to the VERITAS AGN
observation program, resulting in 34 detections. Most of these detections are
accompanied by contemporaneous, broadband observations, enabling a more
detailed study of the underlying jet-powered processes. Recent highlights of
the VERITAS AGN observation program are presented.


title:
Solar Axion Search Technique with Correlated Signals from Multiple
  Detectors

abstract:
  The coherent Bragg scattering of photons converted from solar axions inside
crystals would boost the signal for axion-photon coupling enhancing
experimental sensitivity for these hypothetical particles. Knowledge of the
scattering angle of solar axions with respect to the crystal lattice is
required to make theoretical predications of signal strength. Hence, both the
lattice axis angle within a crystal and the absolute angle between the crystal
and the Sun must be known. In this paper, we examine how the experimental
sensitivity changes with respect to various experimental parameters. We also
demonstrate that, in a multiple-crystal setup, knowledge of the relative axis
orientation between multiple crystals can improve the experimental sensitivity,
or equivalently, relax the precision on the absolute solar angle measurement.
However, if absolute angles of all crystal axes are measured, we find that a
precision of 2-4 degrees will suffice for an energy resolution of
$\sigma_E=0.04{\rm E}$ and a flat background. Finally, we also show that, given
a minimum number of detectors, a signal model averaged over angles can
substitute for precise crystal angular measurements, with some loss of
sensitivity.


title:
Optimal approximation of SDEs on submanifolds: the Ito-vector and
  Ito-jet projections

abstract:
  We define two new notions of projection of a stochastic differential equation
(SDE) onto a submanifold: the Ito-vector and Ito-jet projections. This allows
one to systematically develop low dimensional approximations to high
dimensional SDEs using differential geometric techniques. The approach
generalizes the notion of projecting a vector field onto a submanifold in order
to derive approximations to ordinary differential equations, and improves the
previous Stratonovich projection method by adding optimality analysis and
results. Indeed, just as in the case of ordinary projection, our definitions of
projection are based on optimality arguments and give in a well-defined sense
"optimal" approximations to the original SDE in the mean-square sense. We also
show that the Stratonovich projection satisfies an optimality criterion that is
more ad hoc and less appealing than the criteria satisfied by the Ito
projections we introduce. As an application we consider approximating the
solution of the non-linear filtering problem with a Gaussian distribution and
show how the newly introduced Ito projections lead to optimal approximations in
the Gaussian family and briefly discuss the optimal approximation for more
general families of distribution. We perform a numerical comparison of our
optimally approximated filter with the classical Extended Kalman Filter to
demonstrate the efficacy of the approach.


title: On face numbers of flag simplicial complexes

abstract:
  Denham, Suciu and Panov, Ray computed ranks of homotopy groups and Poincar\'e
series of a moment-angle-complex $\mathcal Z(\mathcal K$) / Davis-Januzskiewicz
space $DJ(\mathcal K)$ associated to a flag simplicial complex $\mathcal K$. In
this note we revisit these results and interpret them as polynomial bounds on
the face numbers of an arbitrary simplicial flag complex.


title:
An Example of Rank 2 Poisson Structure which is Stable Under
  Deformations

abstract:
  Let $\Pi$ be a rank $2$ Poisson Structure in the Projective Space defined by
the dimension $2$ foliation $\mathcal{F}$ in the pull-back component. We prove
that for a generic choice of $\mathcal{F}$, the irreducible component of the
Poisson structures containing $\Pi$ and the irreducible component of Foliations
containing $\mathcal{F}$ coincides.


title:
Bounds for the scale of inflation and the tensor-to-scalar ratio in
  Hybrid Natural Inflation

abstract:
  Recently we have studied in great detail a model of Hybrid Natural Inflation
(HNI) by constructing two simple effective field theories. These two versions
of the model allow inflationary energy scales as small as the electroweak scale
in one of them or as large as the Grand Unification scale in the other
therefore covering the whole range of possible energy scales. The inflationary
sector of the model is of the form $V(\phi)=V_0 \left(1+a \cos(\phi/f)\right)$
where $0\leq a<1$ and the end of inflation is triggered by an independent
waterfall field. One interesting characteristic of this type of models is that
the tensor-to-scalar ratio $r$ is a non-monotonic function of $\phi$ presenting
a {\it maximum} close to the inflection point $\phi_I=\pi/2$ of the potential.
Because the scalar spectrum $\mathcal{P}_s(k)$ of density fluctuations when
written in terms of the potential is inversely proportional to $r$ we find that
$\mathcal{P}_s(k)$ presents a {\it minimum} at $\phi_{min}$. We use this
property of HNI together with the observation that the spectrum is decreasing
during the first 8 e-folds of observable inflation to determine bounds for the
inflationary energy scale $\Delta$ and for the tensor-to-scalar ratio $r$.


title: Invariant Solutions of the Yamabe equation on the Koiso-Cao Soliton

abstract:
  We consider the non-trivial Ricci soliton on
$\mathbb{CP}^2\#\overline{\mathbb{CP}^2}$ constructed by Koiso and Cao. It is a
K\"ahler metric invariant by the $U(2)$ action on
$\mathbb{CP}^2\#\overline{\mathbb{CP}^2}$. We study its Yamabe equation and
prove it has exactly one $U(2)-$invariant solution up to homothecies.


title: SNR-Walls in Eigenvalue-based Spectrum Sensing

abstract:
  Various spectrum sensing approaches have been shown to suffer from a
so-called SNR-wall, an SNR value below which a detector cannot perform robustly
no matter how many observations are used. Up to now, the eigenvalue-based
maximum-minimum-eigenvalue (MME) detector has been a notable exception. For
instance, the model uncertainty of imperfect knowledge of the receiver noise
power, which is known to be responsible for the energy detector's fundamental
limits, does not adversely affect the MME detector's performance. While
additive white Gaussian noise (AWGN) is a standard assumption in wireless
communications, it is not a reasonable one for the MME detector. In fact, in
this work we prove that uncertainty in the amount of noise coloring does lead
to an SNR-wall for the MME detector. We derive a lower bound on this SNR-wall
and evaluate it for example scenarios. The findings are supported by numerical
simulations.


title:
Atmospheric Circulation of Hot Jupiters: Dayside-Nightside Temperature
  Differences. II. Comparison with Observations

abstract:
  The full-phase infrared light curves of low-eccentricity hot Jupiters show a
trend of increasing fractional dayside-nightside brightness temperature
difference with increasing incident stellar flux, both averaged across the
infrared and in each individual wavelength band. The analytic theory of Komacek
& Showman (2016) shows that this trend is due to the decreasing ability with
increasing incident stellar flux of waves to propagate from day to night and
erase temperature differences. Here, we compare the predictions of this theory
to observations, showing that it explains well the shape of the trend of
increasing dayside-nightside temperature difference with increasing equilibrium
temperature. Applied to individual planets, the theory matches well with
observations at high equilibrium temperatures but, for a fixed photosphere
pressure of $100 \ \mathrm{mbar}$, systematically under-predicts the
dayside-nightside brightness temperature differences at equilibrium
temperatures less than $2000 \ \mathrm{K}$. We interpret this as due to as the
effects of a process that moves the infrared photospheres of these cooler hot
Jupiters to lower pressures. We also utilize general circulation modeling with
double-grey radiative transfer to explore how the circulation changes with
equilibrium temperature and drag strengths. As expected from our theory, the
dayside-nightside temperature differences from our numerical simulations
increase with increasing incident stellar flux and drag strengths. We calculate
model phase curves using our general circulation models, from which we compare
the broadband infrared offset from the substellar point and dayside-nightside
brightness temperature differences against observations, finding that strong
drag or additional effects (e.g. clouds and/or supersolar metallicities) are
necessary to explain many observed phase curves.


title: Not-that-heavy Majorana neutrino signals at the LHC

abstract:
  We consider the possibility of Majorana neutrinos production at the Large
Hadron Collider (LHC) by studying the $pp \rightarrow l_i^{+} l_j^{+} +2~jets$
($l_j\equiv e ,\mu$) process which, due to leptonic number violation, is a
clear signature for intermediate Majorana neutrino contributions. The
interactions between Majorana neutrinos and the Standard Model particles are
obtained from an effective lagrangian approach. Majorana neutrinos with masses
of a few $GeV$ are long-lived neutral particles, and we take advantage of its
measurable decay length: in the same-sign dilepton channel, we exploit this
fact imposing cuts that reject the $SM$ background, and analyze the
distribution corresponding to the angle between the final leptons, using a
forward-backward asymmetry to study the effects of the different gauge
invariant operators. We also study the $pp\rightarrow l_i^+ \nu \gamma$
process, which is dominant for low $m_N$ masses if tensorial one-loop generated
new physics contributions are present. This channel could be observed at the
LHC with the aid of non-pointing photons observables and cuts on the
displacement between the prompt lepton and the photon.


title:
Exact master equation for a spin interacting with a spin bath:
  Non-Markovianity and negative entropy production rate

abstract:
  An exact canonical master equation of the Lindblad form is derived for a
central spin interacting uniformly with a sea of completely unpolarized spins.
The Kraus operators for the dynamical map are also derived. The
non-Markovianity of the dynamics in terms of the divisibility breaking of the
dynamical map and increase of the trace distance fidelity between quantum
states is shown. Moreover, it is observed that the irreversible entropy
production rate is always negative (for a fixed initial state) whenever the
dynamics exhibits non-Markovian behavior. In continuation with the study of
witnessing non-Markovianity, it is shown that the positive rate of change of
the purity of the central qubit is a faithful indicator of the non-Markovian
information back flow. Given the experimental feasibility of measuring the
purity of a quantum state, a possibility of experimental demonstration of
non-Markovianity and the negative irreversible entropy production rate is
addressed. This gives the present work considerable practical importance for
detecting the non-Markovianity and the negative irreversible entropy production
rate.


title: Molino theory for matchbox manifolds

abstract:
  A matchbox manifold is a foliated space with totally disconnected
transversals, and an equicontinuous matchbox manifold is the generalization of
Riemannian foliations for smooth manifolds in this context. In this paper, we
develop the Molino theory for all equicontinuous matchbox manifolds. Our work
extends the Molino theory developed in the work of \'Alvarez L\'opez and
Moreira Galicia which required the hypothesis that the holonomy actions for
these spaces satisfy the strong quasi-analyticity condition. The methods of
this paper are based on the authors' previous works on the structure of weak
solenoids, and provide many new properties of the Molino theory for the case of
totally disconnected transversals, and examples to illustrate these properties.
In particular, we show that the Molino space need not be uniquely well-defined,
unless the global holonomy dynamical system is tame, a notion defined in this
work. We show that examples in the literature for the theory of weak solenoids
provide examples for which the strong quasi-analytic condition fails. Of
particular interest is a new class of examples of equicontinuous minimal Cantor
actions by finitely generated groups, whose construction relies on a result of
Lubotzky. These examples have non-trivial Molino sequences, and other
interesting properties.


title: Super-fast MST Algorithms in the Congested Clique using $o(m)$ Messages

abstract:
  In a sequence of recent results (PODC 2015 and PODC 2016), the running time
of the fastest algorithm for the \emph{minimum spanning tree (MST)} problem in
the \emph{Congested Clique} model was first improved to $O(\log \log \log n)$
from $O(\log \log n)$ (Hegeman et al., PODC 2015) and then to $O(\log^* n)$
(Ghaffari and Parter, PODC 2016). All of these algorithms use $\Theta(n^2)$
messages independent of the number of edges in the input graph.
  This paper positively answers a question raised in Hegeman et al., and
presents the first "super-fast" MST algorithm with $o(m)$ message complexity
for input graphs with $m$ edges. Specifically, we present an algorithm running
in $O(\log^* n)$ rounds, with message complexity $\tilde{O}(\sqrt{m \cdot n})$
and then build on this algorithm to derive a family of algorithms, containing
for any $\varepsilon$, $0 < \varepsilon \le 1$, an algorithm running in
$O(\log^* n/\varepsilon)$ rounds, using $\tilde{O}(n^{1 +
\varepsilon}/\varepsilon)$ messages. Setting $\varepsilon = \log\log n/\log n$
leads to the first sub-logarithmic round Congested Clique MST algorithm that
uses only $\tilde{O}(n)$ messages.
  Our primary tools in achieving these results are (i) a component-wise bound
on the number of candidates for MST edges, extending the sampling lemma of
Karger, Klein, and Tarjan (Karger, Klein, and Tarjan, JACM 1995) and (ii)
$\Theta(\log n)$-wise-independent linear graph sketches (Cormode and Firmani,
Dist.~Par.~Databases, 2014) for generating MST candidate edges.


title:
Semi-Coupled Two-Stream Fusion ConvNets for Action Recognition at
  Extremely Low Resolutions

abstract:
  Deep convolutional neural networks (ConvNets) have been recently shown to
attain state-of-the-art performance for action recognition on
standard-resolution videos. However, less attention has been paid to
recognition performance at extremely low resolutions (eLR) (e.g., 16 x 12
pixels). Reliable action recognition using eLR cameras would address privacy
concerns in various application environments such as private homes, hospitals,
nursing/rehabilitation facilities, etc. In this paper, we propose a
semi-coupled filter-sharing network that leverages high resolution (HR) videos
during training in order to assist an eLR ConvNet. We also study methods for
fusing spatial and temporal ConvNets customized for eLR videos in order to take
advantage of appearance and motion information. Our method outperforms
state-of-the-art methods at extremely low resolutions on IXMAS (93.7%) and HMDB
(29.2%) datasets.


title: Generalization bound for kernel similarity learning

abstract:
  Similarity learning has received a large amount of interest and is an
important tool for many scientific and industrial applications. In this
framework, we wish to infer the distance (similarity) between points with
respect to an arbitrary distance function $d$. Here, we formulate the problem
as a regression from a feature space $\mathcal{X}$ to an arbitrary vector space
$\mathcal{Y}$, where the Euclidean distance is proportional to $d$. We then
give Rademacher complexity bounds on the generalization error. We find that
with high probability, the complexity is bounded by the maximum of the radius
of $\mathcal{X}$ and the radius of $\mathcal{Y}$.


title: Automatic sequences, generalised polynomials, and nilmanifolds

abstract:
  We conjecture that bounded generalised polynomial functions cannot be
generated by finite automata, except for the trivial case when they are
periodic away from a finite set. Using methods from ergodic theory, we are able
to partially resolve this conjecture, proving that any hypothetical
counterexample is periodic away from a very sparse and structured set. In
particular, we show that for a polynomial $p(n)$ with at least one irrational
coefficient (except for the constant one) and integer $m$, the sequence
$\lfloor p(n) \rfloor \bmod{m}$ is never automatic. We also obtain a
conditional result, where we prove the conjecture under the assumption that the
characteristic sequence of the set of powers of an integer $k\geq 2$ is not
given by a generalised polynomial.


title:
The Role of Reciprocity and Directionality of Friendship Ties in
  Promoting Behavioral Change

abstract:
  Friendship is a fundamental characteristic of human beings and usually
assumed to be reciprocal in nature. Despite this common expectation, in
reality, not all friendships by default are reciprocal nor created equal. Here,
we show that reciprocated friendships are more intimate and they are
substantially different from those that are not. We examine the role of
reciprocal ties in inducing more effective peer pressure in a cooperative
arrangements setting and find that the directionality of friendship ties can
significantly limit the ability to persuade others to act. Specifically, we
observe a higher behavioral change and more effective peer-influence when
subjects shared reciprocal ties with their peers compared to sharing unilateral
ones. Moreover, through spreading process simulation, we find that although
unilateral ties diffuse behaviors across communities, reciprocal ties play more
important role at the early stages of the diffusion process.


title:
Straintronic magneto-tunneling-junction based ternary content
  addressable memory

abstract:
  Straintronic magneto-tunneling junction (s-MTJ) switches, whose resistances
are controlled with voltage-generated strain in the magnetostrictive free layer
of the MTJ, are extremely energy-efficient switches that would dissipate a few
aJ of energy during switching. Unfortunately, they are also relatively
error-prone and have low resistance on/off ratio. This suggests that as
computing elements, they are best suited for non-Boolean architectures. Here,
we propose and analyze a ternary content addressable memory implemented with
s-MTJs and some transistors. It overcomes challenges encountered by traditional
all-transistor implementations, resulting in exceptionally high cell density.


title:
Photocurrent Enhancement of Graphene Photodetectors by Photon Tunneling
  of Light into Surface Plasmons

abstract:
  We demonstrate that surface plasmon resonances excited by photon tunneling
through an adjacent dielectric medium enhance photocurrent detected by a
graphene photodetector. The device is created by overlaying a graphene sheet
over an etched gap in a gold film deposited on glass. The detected
photocurrents are compared for five different excitation wavelengths, ranging
from nm to nm. The photocurrent excited with incident p-polarized light (the
case for resonant surface plasmon excitation) is significantly amplified in
comparison with that for s-polarized light (without surface plasmon
resonances). We observe that the photocurrent is greater for shorter
wavelengths (for both s and p-polarizations) due to the increased photothermal
current resulting from higher damping of surface plasmons at shorter wavelength
excitation. Position-dependent Raman spectroscopic analysis of the
optically-excited graphene photodetector indicates the presence of charge
carriers near the metallic edge. In addition, we show that the polarity of
photocurrent switches across the gap as the incident light spot moves across
the gap. Graphene-based photodetectors offer a simple architecture which can be
fabricated on dielectric waveguides to exploit the plasmonic photocurrent
enhancement of the evanescent field for detection. Applications for these
devices include photo-detection, optical sensing and direct plasmonic
detection.


title: Geometric entanglement in the Laughlin wave function

abstract:
  We study numerically the geometric entanglement in the Laughlin wave
function, which is of great importance in condensed matter physics. The Slater
determinant having the largest overlap with the Laughlin wave function is
constructed by an iterative algorithm. The logarithm of the overlap, which is a
geometric quantity, is then taken as a geometric measure of entanglement. It is
found that the geometric entanglement is a linear function of the number of
electrons to a good extent. This is especially the case for the lowest Laughlin
wave function, namely the one with filling factor of $1/3$. Surprisingly, the
linear behavior extends well down to the smallest possible value of the
electron number, namely, $ N= 2$. The constant term does not agree with the
expected topological entropy.


title: Shock responses of nanoporous aluminum by molecular dynamics simulations

abstract:
  We present systematic investigations on the shock responses of nanoporous
aluminum (np-Al) by nonequilibrium molecular dynamics simulations. The
dislocation nucleation sites are found to concentrate in low latitude region
near the equator of the spherical void surfaces. We propose a continuum wave
reflection theory and a resolved shear stress model to explain the distribution
of dislocation nucleation sites. The simulations reveals two mechanisms of void
collapse: the plasticity mechanism and the internal jetting mechanism. The
plasticity mechanism, which leads to transverse collapse of voids, prevails
under relatively weaker shocks; while the internal jetting mechanism, which
leads to longitudinal filling of the void vacuum, plays more significant role
as the shock intensity increases. In addition, an abnormal thermodynamic
phenomenon (i.e., arising of temperature with pressure dropping) in shocked
np-Al is discovered. This phenomenon is incompatible with the conventional
Rankine-Hugoniot theory, and is explained by the nonequilibrium processes
involved in void collapse. The influences of void collapse on spall fracture of
np-Al is studied. Under the same loading velocity, the spall strength of np-Al
is found to be lower than that of single-crystal Al; but the spall resistance
is higher in np-Al than in single-crystal Al. This is explained by the combined
influences of thermal dissipation and stress attenuation during shock wave
propagation in np-Al.


title: Single Controller Stochastic Games for Optimized Moving Target Defense

abstract:
  Moving target defense (MTD) techniques that enable a system to randomize its
configuration to thwart prospective attacks are an effective security solution
for tomorrow's wireless networks. However, there is a lack of analytical
techniques that enable one to quantify the benefits and tradeoffs of MTDs. In
this paper, a novel approach for implementing MTD techniques that can be used
to randomize cryptographic techniques and keys in wireless networks is
proposed. In particular, the problem is formulated as a stochastic game in
which a base station (BS), acting as a defender seeks to strategically change
its cryptographic techniques and keys in an effort to deter an attacker that is
trying to eavesdrop on the data. The game is shown to exhibit a
single-controller property in which only one player, the defender, controls the
state of the game. For this game, the existence and properties of the Nash
equilibrium are studied, in the presence of a defense cost for using MTD. Then,
a practical algorithm for deriving the equilibrium MTD strategies is derived.
Simulation results show that the proposed game-theoretic MTD framework can
significantly improve the overall utility of the defender, while enabling
effective randomization over cryptographic techniques.


title:
The space of short ropes and the classifying space of the space of long
  knots

abstract:
  We prove affirmatively the conjecture raised by J. Mostovoy; the space of
short ropes is weakly homotopy equivalent to the classifying space of the
topological monoid (or category) of long knots in $\mathbb{R}^3$. We make use
of techniques developed by S. Galatius and O. Randal-Williams to construct a
manifold space model of the classifying space of the space of long knots, and
we give an explicit map from the space of short ropes to the model in a
geometric way.


title: Order Quasisymmetric Functions Distinguish Rooted Trees

abstract:
  Richard P. Stanley conjectured that finite trees can be distinguished by
their chromatic symmetric functions. In this paper, we prove an analogous
statement for posets: Finite rooted trees can be distinguished by their order
quasisymmetric functions.


title: Equivalence-principle Analog of the Gravitational Redshift

abstract:
  What happens when two synchronized clocks on a rigid beam are both given the
exact same acceleration profile? Will they remain synchronized? What if we use
a rigid-rod Rindler acceleration profile? The special relativity prediction
surprises many people. This experimental setup is the special-relativity analog
of the gravitational redshift. Just like two clocks higher and lower in a
gravitational field lose synchronization, one sees a loss of synchronization in
these clocks with `identical' acceleration profiles. To the best of our
knowledge this equivalence principle analog has never been directly measured,
and current experimental techniques are sensitive enough to measure it. We
discuss the origin of the essential physics behind this synchronization loss,
and some special conditions which simplify its experimental observation. We
discuss the origin of the essential physics behind this synchronization loss,
and some special conditions which simplify its experimental observation. If
validated this effect will not only test the equivalence principle from a new
vantage, but it may one day aid in understanding and enhancing future
ultra-precise navigation systems.


title:
Global Stability of the Nontrivial Solutions to the Wave Map Problem
  from Kerr $|a|\ll M$ to the Hyperbolic Plane under Axisymmetric Perturbations
  Preserving Angular Momentum

abstract:
  This document proves global boundedness and decay for axisymmetric
perturbations of a known solution to the wave map problem from a slowly
rotating $|a|\ll M$ Kerr spacetime to the hyperbolic plane. This problem is
motivated by the general axisymmetric stability of Kerr conjecture and was
first posed by Ionescu and Klainerman in [IK14]. Two particular developments in
this paper, the treatment of terms near the axis of symmetry and the use of a
decay hierarchy for energy estimates on uniformly spacelike hypersurfaces, can
be used for a variety of similar problems.


title: Zoo of quantum-topological phases of matter

abstract:
  What are topological phases of matter? First, they are phases of matter at
zero temperature. Second, they have a non-zero energy gap for the excitations
above the ground state. Third, they are disordered liquids that seem have no
feature. But those disordered liquids actually can have rich patterns of
many-body entanglement representing new kinds of order. This paper will give a
simple introduction and a brief survey of topological phases of matter. We will
first discuss topological phases that have topological order (ie with long
range entanglement). Then we will cover topological phases that have no
topological order (ie with only short-range entanglement).


title:
Normal scalar curvature inequality on the focal submanifolds of
  isoparametric hypersurfaces

abstract:
  An isoparametric hypersurface in unit spheres has two focal submanifolds.
Condition A plays a crucial role in the classification theory of isoparametric
hypersurfaces in [CCJ07], [Chi16] and [Miy13]. This paper determines $C_A$, the
set of points with Condition A in focal submanifolds. It turns out that the
points in $C_A$ reach an upper bound of the normal scalar curvature
$\rho^{\bot}$ (sharper than that in DDVV inequality [GT08], [Lu11]). We also
determine the sets $C_P$ (points with parallel second fundamental form) and
$C_E$ (points with Einstein condition), which achieve two lower bounds of
$\rho^{\bot}$.


title:
A Resolved Near-Infrared Image of The Inner Cavity in The GM Aur
  Transitional Disk

abstract:
  We present high-contrast H-band polarized intensity (PI) images of the
transitional disk around the young solar-like star GM Aur. The near-infrared
direct imaging of the disk was derived by polarimetric differential imaging
using the Subaru 8.2-m Telescope and HiCIAO. An angular resolution and an inner
working angle of 0."07 and r~0."05, respectively, were obtained. We clearly
resolved a large inner cavity, with a measured radius of 18+/-2 au, which is
smaller than that of a submillimeter interferometric image (28 au). This
discrepancy in the cavity radii at near-infrared and submillimeter wavelengths
may be caused by a 3-4M_Jup planet about 20 au away from the star, near the
edge of the cavity. The presence of a near-infrared inner is a strong
constraint on hypotheses for inner cavity formation in a transitional disk. A
dust filtration mechanism has been proposed to explain the large cavity in the
submillimeter image, but our results suggest that this mechanism must be
combined with an additional process. We found that the PI slope of the outer
disk is significantly different from the intensity slope obtained from
HST/NICMOS, and this difference may indicate the grain growth process in the
disk.


title:
Mapping Between fMRI Responses to Movies and their Natural Language
  Annotations

abstract:
  Several research groups have shown how to correlate fMRI responses to the
meanings of presented stimuli. This paper presents new methods for doing so
when only a natural language annotation is available as the description of the
stimulus. We study fMRI data gathered from subjects watching an episode of BBCs
Sherlock [1], and learn bidirectional mappings between fMRI responses and
natural language representations. We show how to leverage data from multiple
subjects watching the same movie to improve the accuracy of the mappings,
allowing us to succeed at a scene classification task with 72% accuracy (random
guessing would give 4%) and at a scene ranking task with average rank in the
top 4% (random guessing would give 50%). The key ingredients are (a) the use of
the Shared Response Model (SRM) and its variant SRM-ICA [2, 3] to aggregate
fMRI data from multiple subjects, both of which are shown to be superior to
standard PCA in producing low-dimensional representations for the tasks in this
paper; (b) a sentence embedding technique adapted from the natural language
processing (NLP) literature [4] that produces semantic vector representation of
the annotations; (c) using previous timestep information in the featurization
of the predictor data.


title: Prediction of Influenza B Vaccine Effectiveness from Sequence Data

abstract:
  Influenza is a contagious respiratory illness that causes significant human
morbidity and mortality, affecting 5-15% of the population in a typical
epidemic season. Human influenza epidemics are caused by types A and B, with
roughly 25% of human cases due to influenza B. Influenza B is a single-stranded
RNA virus with a high mutation rate, and both prior immune history and
vaccination put significant pressure on the virus to evolve. Due to the high
rate of viral evolution, the influenza B vaccine component of the annual
influenza vaccine is updated, roughly every other year in recent years. To
predict when an update to the vaccine is needed, an estimate of expected
vaccine effectiveness against a range of viral strains is required. We here
introduce a method to measure antigenic distance between the influenza B
vaccine and circulating viral strains. The measure correlates well with
effectiveness of the influenza B component of the annual vaccine in humans
between 1979 and 2014. We discuss how this measure of antigenic distance may be
used in the context of annual influenza vaccine design and prediction of
vaccine effectiveness.


title: Upper bound on three tangles of reduced states of four-qubit pure states

abstract:
  Closed formulae for upper bound on three tangles of three-qubit reduced
states in terms of three-qubit invariant polynomials of pure four-qubit states
are obtained. Our results offer tighter constraints on total three-way
entanglement of a given qubit with the rest of the system than those used in
ref. [PRL 113, 110501 (2014), PRL 116, 049902(E) (2016)] to verify monogamy of
four-qubit quantum entanglement.


title:
Concise Summarization of Heterogeneous Treatment Effect Using Total
  Variation Regularized Regression

abstract:
  Randomized controlled experiment has long been accepted as the golden
standard for establishing causal link and estimating causal effect in various
scientific fields. Average treatment effect is often used to summarize the
effect estimation, even though treatment effects are commonly believed to be
varying among individuals. In the recent decade with the availability of "big
data", more and more experiments have large sample size and increasingly rich
side information that enable and require experimenters to discover and
understand heterogeneous treatment effect (HTE). There are two aspects in HTE
understanding, one is to predict the effect conditioned on a given set of side
information or a given individual, the other is to interpret the HTE structure
and summarize it in a memorable way. The former aspect can be treated as a
regression problem, and the latter aspect focuses on concise summarization and
interpretation. In this paper we propose a method that can achieve both at the
same time. This method can be formulated as a convex optimization problem, for
which we provide stable and scalable implementation.


title:
Development of Particle-in-Cell Simulation in a Two Dimensional Trench
  Geometry

abstract:
  A two dimensional electrostatic Particle-in-Cell simulation code is developed
to investigate anisotropy of ions in a trench geometry for plasma etching. The
numerical simulation results suggest that if the trench width is larger than
Debye length scale, anisotropy can be lost due to potential development across
the trench. Furthermore, the effects of ion charge build up on the trench
bottom is investigated, which can degrade the anisotropy.


title:
Non-equilibrium quantum phase transition via entanglement decoherence
  dynamics

abstract:
  We investigate the decoherence dynamics of continuous variable entanglement
as the system-environment coupling strength varies from the weak-coupling to
the strong-coupling regimes. Due to the existence of localized modes in the
strong-coupling regime, the system cannot approach equilibrium with its
environment, which induces a nonequilibrium quantum phase transition. We
analytically solve the entanglement decoherence dynamics for an arbitrary
spectral density. The nonequilibrium quantum phase transition is demonstrated
as the system-environment coupling strength varies for all the Ohmic-type
spectral densities. The 3-D entanglement quantum phase diagram is obtained.


title:
The combinatorics of $\mathbb{C}^*$-fixed points in generalized
  Calogero-Moser spaces and Hilbert schemes

abstract:
  In this paper we study the combinatorial consequences of the relationship
between rational Cherednik algebras of type $G(l,1,n)$, cyclic quiver varieties
and Hilbert schemes. We classify and explicitly construct $\mathbb{C}^*$-fixed
points in cyclic quiver varieties and calculate the corresponding characters of
tautological bundles. Furthermore, we give a combinatorial description of the
bijections between $\mathbb{C}^*$-fixed points induced by the Etingof-Ginzburg
isomorphism and Nakajima reflection functors. We apply our results to obtain a
new proof as well as a generalization of the $q$-hook formula.


title:
Polarization-mediated Debye-screening of surface potential fluctuations
  in dual-channel AlN/GaN high electron mobility transistors

abstract:
  A dual-channel AlN/GaN/AlN/GaN high electron mobility transistor (HEMT)
architecture is proposed, simulated, and demonstrated that suppresses gate lag
due to surface-originated trapped charge. Dual two-dimensional electron gas
(2DEG) channels are utilized such that the top 2DEG serves as an equipotential
that screens potential fluctuations resulting from surface trapped charge. The
bottom channel serves as the transistor's modulated channel. Two device
modeling approaches have been performed as a means to guide the device design
and to elucidate the relationship between the design and performance metrics.
The modeling efforts include a self-consistent Poisson-Schrodinger solution for
electrostatic simulation as well as hydrodynamic three-dimensional device
modeling for three-dimensional electrostatics, steady-state, and transient
simulations. Experimental results validated the HEMT design whereby
homo-epitaxial growth on free-standing GaN substrates and fabrication of
same-wafer dual-channel and recessed-gate AlN/GaN HEMTs have been demonstrated.
Notable pulsed-gate performance has been achieved by the fabricated HEMTs
through a gate lag ratio of 0.86 with minimal drain current collapse while
maintaining high levels of dc and rf performance.


title:
Effect of Window Shape on the Detection of Hyperuniformity via the Local
  Number Variance

abstract:
  Hyperuniform many particle systems in d-dimensional space, which includes
crystals, quasicrystals, and some exotic disordered systems, are characterized
by an anomalous suppression of density fluctuations at large length scales such
that the local number variance within a "spherical" observation window grows
slower than the window volume. In usual circumstances, this direct space
condition is equivalent to the Fourier space hyperuniformity condition that the
structure factor vanishes as the wavenumber goes to zero. In this paper, we
comprehensively study the effect of aspherical window shapes with
characteristic size $L$ on the direct space condition for hyperuniform systems.
For lattices, we demonstrate that the variance growth rate can depend on the
shape as well as the orientation of the windows, and in some cases, the growth
rate can be faster than the window volume ($L^d$), which may lead one to
falsely conclude that the system is non-hyperuniform solely according to the
direct space condition. We analyze the effect of window orientation on the
growth rate, especially for two-dimensional lattices using square windows.
Based on this analysis, we explain the reason why the variance can grow faster
than the window area ($L^2$) or even slower than the window perimeter ($L$).
This analysis demonstrates an example of physical systems exhibiting
commensurate-incommensurate transitions and is closely related to problems in
number theory (e.g., Diophantine approximation and Gauss' circle problem) and
discrepancy theory. We prove that for a hyperuniform system its
orientationally-averaged variance, instead of the conventional one using
windows with a fixed orientation, has a common large-$L$ asymptotic behavior
regardless of the window shape (for convex windows), thus it can be used to
resolve the window-shape dependence of the growth rate of the variance on the
spherical-window condition.


title: Liouville property for $f$-harmonic functions with polynomial growth

abstract:
  We prove a Liouville property for any $f$-harmonic function with polynomial
growth on a complete noncompact smooth metric measure space $(M,g,e^{-f}dv)$
when the Bakry-\'Emery Ricci curvature is nonnegative and its diameter of
geodesic sphere has sublinear growth.


title: Short fans and the 5/6 bound for line graphs

abstract:
  In 2011, the second author conjectured that every line graph $G$ satisfies
$\chi(G)\le \max\{\omega(G),\frac{5\Delta(G)+8}{6}\}$. This conjecture is best
possible, as shown by replacing each edge in a 5-cycle by $k$ parallel edges,
and taking the line graph. In this paper we prove the conjecture. We also
develop more general techniques and results that will likely be of independent
interest, due to their use in attacking the Goldberg--Seymour conjecture.


title:
The complex, dusty narrow-line region of NGC 4388: Gas-jet interactions,
  outflows, and extinction revealed by near-IR spectroscopy

abstract:
  We present Gemini/GNIRS spectroscopy of the Seyfert 2 galaxy NGC 4388, with
simultaneous coverage from 0.85 - 2.5 $\mu$m. Several spatially-extended
emission lines are detected for the first time, both in the obscured and
unobscured portion of the optical narrow line region (NLR), allowing us to
assess the combined effects of the central continuum source, outflowing gas and
shocks generated by the radio jet on the central 280 pc gas. The HI and [FeII]
lines allow us to map the extinction affecting the NLR. We found that the
nuclear region is heavily obscured, with E(B-V) ~1.9 mag. To the NE of the
nucleus and up to ~150 pc, the extinction remains large, ~1 mag or larger,
consistent with the system of dust lanes seen in optical imaging. We derived
position-velocity diagrams for the most prominent lines as well as for the
stellar component. Only the molecular gas and the stellar component display a
well-organized pattern consistent with disk rotation. Other emission lines are
kinematically perturbed or show little evidence of rotation. Extended
high-ionization emission of sulfur, silicon and calcium is observed to
distances of at least 200 pc both NE and SW of the nucleus. We compared flux
ratios between these lines with photoionization models and conclude that
radiation from the central source alone cannot explain the observed
high-ionization spectrum. Shocks between the radio-jet and the ambient gas are
very likely an additional source of excitation. We conclude that NGC 4388 is a
prime laboratory to study the interplay between all these mechanisms.


title: Comparison geometry for integral Bakry-\'Emery Ricci tensor bounds

abstract:
  We prove mean curvature and volume comparison estimates on smooth metric
measure spaces when their integral Bakry-\'{E}mery Ricci tensor bounds,
extending Wei-Wylie's comparison results to the integral case. We also apply
comparison results to get diameter estimates, eigenvalue estimates and volume
growth estimates on smooth metric measure spaces with their normalized integral
smallness for Bakry-\'{E}mery Ricci tensor. These give generalizations of some
work of Petersen-Wei, Aubry, Petersen-Sprouse, Yau and more.


title: Statistical Inference Using Mean Shift Denoising

abstract:
  In this paper, we study how the mean shift algorithm can be used to denoise a
dataset. We introduce a new framework to analyze the mean shift algorithm as a
denoising approach by viewing the algorithm as an operator on a distribution
function. We investigate how the mean shift algorithm changes the distribution
and show that data points shifted by the mean shift concentrate around high
density regions of the underlying density function. By using the mean shift as
a denoising method, we enhance the performance of several clustering
techniques, improve the power of two-sample tests, and obtain a new method for
anomaly detection.


title:
Cross-Device User Matching Based on Massive Browse Logs: The Runner-Up
  Solution for the 2016 CIKM Cup

abstract:
  As the number and variety of smart devices increase, users may use myriad
devices in their daily lives and the online activities become highly
fragmented. Building an accurate user identity becomes a difficult and
important problem for advertising companies. The task for the CIKM Cup 2016
Track 1 was to find the same user cross multiple devices. This paper discusses
our solution to the challenge. It is mainly comprised of three parts:
comprehensive feature engineering, negative sampling, and model selection. For
each part we describe our special steps and demonstrate how the performance is
boosted. We took the second prize of the competition with an F1-score of
0.41669.