title:
A Catalog of Calibrator Stars for Next-Generation Optical
  Interferometers

abstract:
  Benchmark stars with known angular diameters are key to calibrating
interferometric observations. With the advent of optical interferometry, there
is a need for suitably bright, well-vetted calibrator stars over a large
portion of the sky. We present a catalog of uniformly computed angular
diameters for 1523 stars in the northern hemisphere brighter than V = 6 and
with declinations $-15^\circ < \delta < 82^\circ$. The median angular stellar
diameter is 0.527 mas. The list has been carefully cleansed of all known binary
and multiple stellar systems. We derive the angular diameters for each of the
stars by fitting spectral templates to the observed spectral energy
distributions (SEDs) from literature fluxes. We compare these derived angular
diameters against those measured by optical interferometry for 75 of the stars,
as well as to 176 diameter estimates from previous calibrator catalogs, finding
in general excellent agreement. The final catalog includes our goodness-of-fit
metrics as well as an online atlas of our SED fits. The catalog presented here
permits selection of the best calibrator stars for current and future
visible-light interferometric observations.


title:
Height fluctuations of stationary TASEP on a ring in relaxation time
  scale

abstract:
  We consider the totally asymmetric simple exclusion process on a ring with
stationary initial conditions. The crossover between KPZ dynamics and
equilibrium dynamics occurs when time is proportional to the $3/2$ power of the
ring size. We obtain the limit of the height function along the direction of
the characteristic line in this time scale. The two-point covariance function
in this scale is also discussed.


title: On plant roots logical gates

abstract:
  Theoretical constructs of logical gates implemented with plant roots are
morphological computing asynchronous devices. Values of Boolean variables are
represented by plant roots. A presence of a plant root at a given site
symbolises the logical {\sc True}, an absence the logical {\sc False}. Logical
functions are calculated via interaction between roots. Two types of
two-inputs-two-outputs gates are proposed: a gate $\langle x, y \rangle
\rightarrow \langle xy, x+y \rangle$ where root apexes are guided by gravity
and a gate $\langle x, y \rangle \rightarrow \langle \overline{x}y, x \rangle$
where root apexes are guided by humidity. We propose a design of binary
half-adder based on the gates.


title:
Connected and leading disconnected hadronic light-by-light contribution
  to the muon anomalous magnetic moment with physical pion mass

abstract:
  We report a lattice QCD calculation of the hadronic light-by-light
contribution to the muon anomalous magnetic moment at physical pion mass. The
calculation includes the connected diagrams and the leading,
quark-line-disconnected diagrams. We incorporate algorithmic improvements
developed in our previous work. The calculation was performed on the $48^3
\times 96$ ensemble generated with a physical-pion-mass and a 5.5 fm spatial
extent by the RBC and UKQCD collaborations using the chiral, domain wall
fermion (DWF) formulation. We find $a_\mu^{\text{HLbL}} = 5.35 (1.35) \times
10^{- 10}$, where the error is statistical only. The finite-volume and finite
lattice-spacing errors could be quite large and are the subject of on-going
research. The omitted disconnected graphs, while expected to give a correction
of order 10\%, also need to be computed.


title:
Outer-Product-Free Sets for Polynomial Optimization and Oracle-Based
  Cuts

abstract:
  This paper introduces cutting planes that involve minimal structural
assumptions, enabling the generation of strong polyhedral relaxations for a
broad class of problems. We consider valid inequalities for the set $S\cap P$,
where $S$ is a closed set, and $P$ is a polyhedron. Given an oracle that
provides the distance from a point to $S$, we construct a pure cutting plane
algorithm which is shown to converge if the initial relaxation is a polyhedron.
These cuts are generated from convex forbidden zones, or $S$-free sets, derived
from the oracle. We also consider the special case of polynomial optimization.
Accordingly we develop a theory of \emph{outer-product-free} sets, where $S$ is
the set of real, symmetric matrices of the form $xx^T$. All maximal
outer-product-free sets of full dimension are shown to be convex cones and we
identify several families of such sets. These families are used to generate
strengthened intersection cuts that can separate any infeasible extreme point
of a linear programming relaxation efficiently. Computational experiments
demonstrate the promise of our approach.


title:
Exact Diagonalization Study of an Extended Hubbard Model for a Cubic
  Cluster at Quarter Filling

abstract:
  In the paper the thermodynamics of a cubic cluster with 8 sites at quarter
filling is characterized by means of exact diagonalization technique.
Particular emphasis is put on the behaviour of such response functions as
specific heat and magnetic susceptibility. The system is modelled with extended
Hubbard model which includes electron hopping between both first and second
nearest neighbours as well as coulombic interactions, both on-site and between
nearest-neighbour sites. The importance of hopping between second nearest
neighbours and coulombic interactions between nearest neighbours for the
temperature dependences of thermodynamic response functions is analysed. In
particular, the predictions of Schottky model are compared with the
calculations based on the full energy spectrum.


title: KiDS-450: Testing extensions to the standard cosmological model

abstract:
  We test extensions to the standard cosmological model with weak gravitational
lensing tomography using 450 deg$^2$ of imaging data from the Kilo Degree
Survey (KiDS). In these extended cosmologies, which include massive neutrinos,
nonzero curvature, evolving dark energy, modified gravity, and running of the
scalar spectral index, we also examine the discordance between KiDS and cosmic
microwave background measurements from Planck. The discordance between the two
datasets is largely unaffected by a more conservative treatment of the lensing
systematics and the removal of angular scales most sensitive to nonlinear
physics. The only extended cosmology that simultaneously alleviates the
discordance with Planck and is at least moderately favored by the data includes
evolving dark energy with a time-dependent equation of state (in the form of
the $w_0-w_a$ parameterization). In this model, the respective $S_8 = \sigma_8
\sqrt{\Omega_{\rm m}/0.3}$ constraints agree at the $1\sigma$ level, and there
is `substantial concordance' between the KiDS and Planck datasets when
accounting for the full parameter space. Moreover, the Planck constraint on the
Hubble constant is wider than in LCDM and in agreement with the Riess et al.
(2016) direct measurement of $H_0$. The dark energy model is moderately favored
as compared to LCDM when combining the KiDS and Planck measurements, and
remains moderately favored after including an informative prior on the Hubble
constant. In both of these scenarios, marginalized constraints in the $w_0-w_a$
plane are discrepant with a cosmological constant at the $3\sigma$ level.
Moreover, KiDS constrains the sum of neutrino masses to 4.0 eV (95% CL), finds
no preference for time or scale dependent modifications to the metric
potentials, and is consistent with flatness and no running of the spectral
index. The analysis code is public at https://github.com/sjoudaki/kids450


title:
Quantum measurements need not conserve energy: relation to the
  Wigner-Araki-Yanase theorem

abstract:
  The paper focuses on the fact that quantum projective measurements do not
necessarily conserve energy. On the other hand the Wigner-Araki-Yanase (WAY)
theorem states that assuming a "standard" von Neumann measurement model and
"additivity" of the total energy operator, projective measurements of a system
must conserve energy as defined by the system's energy operator. This paper
explores the ideas behind the WAY theorem in hopes of uncovering the origin of
the contradiction.
  After Araki and Yanase published their proof of the WAY theorem, Yanase
appended a new condition now known as the Yanase condition. Under the
simplifying assumption that the observable being measured has discrete and
non-degenerate eigenvalues, we prove that the Yanase condition actually follows
from the hypotheses of the original WAY theorem.
  The paper also proves that the hypotheses of the WAY theorem, together with
the simplifying assumption, imply that the energy operator for the measuring
apparatus must be a multiple of the identity, which seems physically unlikely.
It seems probable that this surprising conclusion, along with the Yanase
condition, also holds without the simplifying assumption.


title:
Dynamics of Mixed Dark Energy Domination in Teleparallel Gravity and
  Phase-Space Analysis

abstract:
  We consider a novel dark energy model to investigate whether it will provide
an expanding universe phase. Here we propose a mixed dark energy domination
which is constituted by tachyon, quintessence, and phantom scalar fields
nonminimally coupled to gravity, in the absence of background dark matter and
baryonic matter, in the framework of teleparallel gravity. We perform the
phase-space analysis of the model by numerical methods and find the late-time
accelerated attractor solutions implying the acceleration phase of universe.


title:
The Relativistic Transactional Interpretation: Immune to the Maudlin
  Challenge

abstract:
  The Transactional Interpretation has been subject at various times to a
challenge based on a type of thought experiment first proposed by Maudlin. It
has been argued by several authors that such experiments do not in fact
constitute a significant problem for the transactional picture. The purpose of
this work is to point out that, when the relativistic level of the
interpretation is considered, Maudlin-type challenges cannot even be mounted,
since the putative 'slow-moving offer wave,' taken as subject to contingent
confirmation, does not exist. This is a consequence of the Davies relativistic
quantum-mechanical version of the direct-action theory together with the
asymmetry between fermionic field sources and bosonic fields. The Maudlin
challenge therefore evaporates completely when the relativistic level of the
theory is taken into account.


title:
Three-dimensional nonlinear micro/meso-mechanical response of the
  fibre-reinforced polymer composites

abstract:
  A three-dimensional multi-scale computational homogenisation framework is
developed for the prediction of nonlinear micro/meso-mechanical response of the
fibre-reinforced polymer (FRP) composites. Two dominant damage mechanisms, i.e.
matrix elasto-plastic response and fibre-matrix decohesion are considered and
modelled using a non-associative pressure dependent paraboloidal yield
criterion and cohesive interface elements respectively. A linear-elastic
transversely isotropic material model is used to model yarns/fibres within the
representative volume element (RVE). A unified approach is used to impose the
RVE boundary conditions, which allows convenient switching between linear
displacement, uniform traction and periodic boundary conditions. The
computational model is implemented within the framework of the hierarchic
finite element, which permits the use of arbitrary orders of approximation.
Furthermore, the computational framework is designed to take advantage of
distributed memory high-performance computing. The accuracy and performance of
the computational framework are demonstrated with a variety of numerical
examples, including unidirectional FRP composite, a composite comprising a
multi-fibre and multi-layer RVE, with randomly generated fibres, and a single
layered plain weave textile composite. Results are validated against the
reference experimental/numerical results from the literature. The computational
framework is also used to study the effect of matrix and fibre-matrix
interfaces properties on the homogenised stress-strain responses.


title: Make Dark Matter Charged Again

abstract:
  We revisit constraints on dark matter that is charged under a $U(1)$ gauge
group in the dark sector, decoupled from Standard Model forces. We find that
the strongest constraints in the literature are subject to a number of
mitigating factors. For instance, the naive dark matter thermalization
timescale in halos is corrected by saturation effects that slow down
isotropization for modest ellipticities. The weakened bounds uncover
interesting parameter space, making models with weak-scale charged dark matter
viable, even with electromagnetic strength interaction. This also leads to the
intriguing possibility that dark matter self-interactions within small dwarf
galaxies are extremely large, a relatively unexplored regime in current
simulations. Such strong interactions suppress heat transfer over scales larger
than the dark matter mean free path, inducing a dynamical cutoff length scale
above which the system appears to have only feeble interactions. These effects
must be taken into account to assess the viability of darkly-charged dark
matter. Future analyses and measurements should probe a promising region of
parameter space for this model.


title: Dark Matter interpretation of low energy IceCube MESE excess

abstract:
  The 2-years MESE IceCube events show a slightly excess in the energy range
10-100 TeV with a maximum local statistical significance of 2.3$\sigma$, once a
hard astrophysical power-law is assumed. A spectral index smaller than 2.2 is
indeed suggested by multi-messenger studies related to $p$-$p$ sources and by
the recent IceCube analysis regarding 6-years up-going muon neutrinos. In the
present paper, we propose a two-components scenario where the extraterrestrial
neutrinos are explained in terms of an astrophysical power-law and a Dark
Matter signal. We consider both decaying and annihilating Dark Matter
candidates with different final states (quarks and leptons) and different halo
density profiles. We perform a likelihood-ratio analysis that provides a
statistical significance up to 3.9$\sigma$ for a Dark Matter interpretation of
the IceCube low energy excess.


title: Novel Spectral Features in MeV Gamma Rays from Dark Matter

abstract:
  Astrophysical searches for gamma rays are one of the main strategies to probe
the annihilation or decay of dark matter particles. We present a new class of
distinct sub-GeV spectral features that generically appear in kinematical
situations where the available center-of-mass energy in such processes is just
above threshold to produce excited meson states. Using a Fisher forecast with
realistic astrophysical backgrounds, we demonstrate that for upcoming
experiments like e-ASTROGAM and ComPair these signals can turn out to be the
smoking gun in the search for particle dark matter.


title: Topological Bootstrap: Fractionalization From Kondo Coupling

abstract:
  We propose a route toward realizing fractionalized topological phases of
matter (i.e. with intrinsic topological order) by literally building on
un-fractionalized phases. Our approach employs a Kondo lattice model in which a
gapped electronic system of non-interacting fermions is coupled to
non-interacting local moments via the exchange interaction. Using general
entanglement-based arguments and explicit lattice models, we show that in this
way gapped spin liquids can be induced in the spin system. We demonstrate the
power of this topological bootstrap concept with two examples: (1) a chiral
spin liquid induced by a Chern insulator and (2) a Z2 spin liquid induced by a
superconductor. In particular, in the latter example, the toric code is
realized as an exactly solvable example of topological bootstrap. Our approach
can be generalized to all lattices, higher dimensions, and non-abelian
topological orders.


title:
The Grism lens-amplified survey from space (GLASS). VIII. The influence
  of the cluster properties on Halpha emitter galaxies at 0.3<z<0.7

abstract:
  Exploiting the data of the Grism Lens-Amplified Survey from Space (GLASS), we
characterize the spatial distribution of star formation in 76 high star forming
galaxies in 10 clusters at 0.3< z <0.7. All these galaxies are likely
restricted to first infall. In a companion paper we contrast the properties of
field and cluster galaxies, whereas here we correlate the properties of
H{\alpha} emitters to a number of tracers of the cluster environment to
investigate its role in driving galaxy transformations. H{\alpha} emitters are
found in the clusters out to 0.5 virial radii, the maximum radius covered by
GLASS. The peak of the H{\alpha} emission is offset with respect to the peak of
the UV-continuum. We decompose this offsets into a radial and tangential
component. The radial compo- nent points away from the cluster center in 60% of
the cases, with 95% confidence. The decompositions agree with cosmological
simulations, i.e. the H{\alpha} emission offset correlates with galaxy velocity
and ram-pressure stripping signatures. Trends between H{\alpha} emitter
properties and surface mass density distributions and X-ray emissions emerge
only for unrelaxed clusters. The lack of strong correlations with the global
environment does not allow us to identify a unique environmental effect
originating from the cluster center. In contrast, correla- tions between
H{\alpha} morphology and local number density emerge. We conclude that local
effects, uncorrelated to the cluster-centric radius, play a more important role
in shaping galaxy properties.


title:
Edge quantum criticality and emergent supersymmetry in topological
  phases

abstract:
  Proposed as a fundamental symmetry describing our universe, spacetime
supersymmetry (SUSY) has not been discovered yet in nature. Nonetheless, it has
been predicted that SUSY may emerge in low-energy physics of quantum materials
such as topological superconductors and Weyl semimetals. Here, by performing
state-of-the-art sign-problem-free Majorana quantum Monte Carlo (QMC)
simulations of an interacting 2D topological superconductor, we show convincing
evidences that the N=1 SUSY emerges at its edge quantum critical point (EQCP)
while its bulk remains gapped and topologically nontrivial. Remarkably, near
the EQCP, we find that the edge Majorana fermion acquires a mass which is
identical with that of its bosonic superpartner. To the best of our knowledge,
this is the first observation that fermions and bosons have equal
dynamically-generated masses, a hallmark of emergent SUSY. We further discuss
experimental signatures of such EQCP and the associated edge SUSY.


title: Mass Distribution in Galaxy Cluster Cores

abstract:
  Many processes within galaxy clusters, such as those believed to govern the
onset of thermally unstable cooling and AGN feedback, are dependent upon local
dynamical timescales. However, accurately mapping the mass distribution within
individual clusters is challenging, particularly towards cluster centres where
the total mass budget has substantial radially-dependent contributions from the
stellar, gas, and dark matter components. In this paper we use a small sample
of galaxy clusters with deep Chandra observations and good ancillary tracers of
their gravitating mass at both large and small radii to develop a method for
determining mass profiles that span a wide radial range and extend down into
the central galaxy. We also consider potential observational pitfalls in
understanding cooling in hot cluster atmospheres, and find tentative evidence
for a relationship between the radial extent of cooling X-ray gas and nebular
H-alpha emission in cool core clusters. Amongst this small sample we find no
support for the existence of a central 'entropy floor', with the entropy
profiles following a power-law profile down to our resolution limit.


title: Inverse Magnetic Catalysis in the Soft-Wall Model of AdS/QCD

abstract:
  Magnetic effects on chiral phase transition have been investigated in a
modified soft-wall AdS/QCD model, in which the dilaton field is taken to be
negative at the ultraviolet region and positive at the infrared region as in
Phys.Rev.D93(2016),101901 and JHEP1604(2016)036. The magnetic field is
introduced into the background geometry by solving the Einstein-Maxwell system.
After embedding the magnetized background geometry into the modified soft-wall
model, the magnetic field dependent behavior of chiral condensate is worked out
numerically. It is found that, in the chiral limit, the chiral phase transition
remains as a second order at finite magnetic field $B$, while the symmetry
restoration temperature and chiral condensate decrease with the increasing of
magnetic field in small $B$ region. When including finite quark mass effect,
the phase transition turns to be a crossover one, and the transition
temperature still decreases with increasing magnetic field $B$ when $B$ is not
very large. In this sense, inverse magnetic catalysis effect is observed in
this modified soft-wall AdS/QCD model.


title:
Solvable model for a dynamical quantum phase transition from fast to
  slow scrambling

abstract:
  We propose an extension of the Sachdev-Ye-Kitaev (SYK) model that exhibits a
quantum phase transition from the previously identified non-Fermi liquid fixed
point to a Fermi liquid like state, while still allowing an exact solution in a
suitable large $N$ limit. The extended model involves coupling the interacting
$N$-site SYK model to a new set of $pN$ peripheral sites with only quadratic
hopping terms between them. The conformal fixed point of the SYK model remains
a stable low energy phase below a critical ratio of peripheral sites $p<p_c(n)$
that depends on the fermion filling $n$. The scrambling dynamics throughout the
non-Fermi liquid phase is characterized by a universal Lyapunov exponent
$\lambda_L\to 2\pi T$ in the low temperature limit, however the temperature
scale marking the crossover to the conformal regime vanishes continuously at
the critical point $p_c$. The residual entropy at $T\to 0$, non zero in the
NFL, also vanishes continuously at the critical point. For $p>p_c$ the
quadratic sites effectively screen the SYK dynamics, leading to a quadratic
fixed point in the low temperature and frequency limit. The interactions have a
perturbative effect in this regime leading to scrambling with Lyapunov exponent
$\lambda_L\propto T^2$.


title: Einasto Profiles and the Dark Matter Power Spectrum

abstract:
  We study the mass accretion histories (MAHs) and density profiles of dark
matter halos using N-body simulations of self-similar gravitational clustering
from scale-free power spectra, $P(k)\propto k^n$. We pay particular attention
to the density profile curvature, which we characterize using the shape
parameter, $\alpha$, of an Einasto profile. In agreement with previous findings
our results suggest that, despite vast differences in their MAHs, the density
profiles of virialized halos are remarkably alike. Nonetheless, clear
departures from self-similarity are evident: for a given spectral index,
$\alpha$ increases slightly but systematically with "peak height",
$\nu\equiv\delta_{sc}/\sigma(M,z)$, regardless of mass or redshift. More
importantly, however, the "$\alpha-\nu$" relation depends on $n$: the steeper
the initial power spectrum, the more gradual the curvature of both the mean
MAHs and mean density profiles. These results are consistent with previous
findings connecting the shapes of halo mass profiles and MAHs and imply that
dark matter halos are not structurally self-similar but, through the merger
history, retain a memory of the linear density field from which they form.


title:
The Grism lens-amplified survey from space (GLASS). VII. The diversity
  of the distribution of star formation in cluster and field galaxies at
  0.3<z<0.7

abstract:
  Exploiting the slitless spectroscopy taken as part of the Grism
Lens-Amplified Survey from Space (GLASS), we present an extended analysis of
the spatial distribution of star formation in 76 galaxies in 10 clusters at
0.3< z <0.7. We use 85 foreground and background galaxies in the same redshift
range as a field sample. The samples are well matched in stellar mass
(10^8-10^11 M_sun) and star formation rate (0.5-50 M_sun/yr). We visually
classify galaxies in terms of broad-band morphology, Halpha morphology and
likely physical process acting on the galaxy. Most Halpha emitters have a
spiral morphology (41+/-8% in clusters, 51+/-8% in the field), followed by
mergers/interactions (28+/-8%, 31+/-7%, respectively) and early-type galaxies
(remarkably as high as 29+/-8% in clusters and 15+/-6% in the field). A
diversity of Halpha morphologies is detected, suggesting a diversity of
physical processes. In clusters, 30+/-8% of the galaxies present a regular
morphology, mostly consistent with star formation diffused uniformly across the
stellar population (mostly in the disk component, when present). The second
most common morphology (28+/-8%) is asymmetric/jellyfish, consistent with ram
pressure stripping or other non-gravitational processes in 18+/-8% of the
cases. Ram pressure stripping appears significantly less prominent in the field
(2+/-2%), where the most common morphology/mechanism appears to be consistent
with minor gas rich mergers or clump accretion. This work demonstrates that
while environment specific mechanisms affect galaxy evolution at this redshift,
they are diverse and their effects subtle. A full understanding of this
complexity requires larger samples and detailed and spatially resolved physical
models.


title:
QCD next-to-leading-order predictions matched to parton showers for
  vector-like quark models

abstract:
  Vector-like quarks are featured by a wealth of beyond the Standard Model
theories and are consequently an important goal of many LHC searches for new
physics. Those searches, as well as most related phenomenological studies,
however rely on predictions evaluated at the leading-order accuracy in QCD and
consider well-defined simplified benchmark scenarios. Adopting an effective
bottom-up approach, we compute next-to-leading-order predictions for
vector-like-quark pair-production and single production in association with
jets, with a weak or with a Higgs boson in a general new physics setup. We
additionally compute vector-like-quark contributions to the production of a
pair of Standard Model bosons at the same level of accuracy. For all processes
under consideration, we focus both on total cross sections and on differential
distributions, most these calculations being performed for the first time in
our field. As a result, our work paves the way to precise extraction of
experimental limits on vector-like quarks thanks to an accurate control of the
shapes of the relevant observables and emphasize the extra handles that could
be provided by novel vector-like-quark probes never envisaged so far


title:
On the origin of the near-infrared emission from the neutron-star
  low-mass X-ray binary GX 9+1

abstract:
  We have determined an improved position for the luminous persistent
neutron-star low-mass X-ray binary and atoll source GX 9+1 from archival
Chandra X-ray Observatory data. The new position significantly differs from a
previously published Chandra position for this source. Based on the revised
X-ray position we have identified a new near-infrared (NIR) counterpart to GX
9+1 in Ks-band images obtained with the PANIC and FourStar cameras on the
Magellan Baade Telescope. NIR spectra of this Ks=16.5+-0.1 mag star taken with
the FIRE spectrograph on the Baade Telescope show a strong Br-gamma emission
line, which is a clear signature that we discovered the true NIR counterpart to
GX 9+1. The mass donor in GX 9+1 cannot be a late-type giant, as such a star
would be brighter than the estimated absolute Ks magnitude of the NIR
counterpart. The slope of the dereddened NIR spectrum is poorly constrained due
to uncertainties in the column density N_H and NIR extinction. Considering the
source's distance and X-ray luminosity, we argue that N_H likely lies near the
high end of the previously suggested range. If this is indeed the case, the NIR
spectrum is consistent with thermal emission from a heated accretion disk,
possibly with a contribution from the secondary. In this respect, GX 9+1 is
similar to other bright atolls and the Z sources whose NIR spectra do not show
the slope that is expected for a dominant contribution from optically thin
synchrotron emission from the inner regions of a jet.


title: Anomaly indicators for time-reversal symmetric topological orders

abstract:
  Some time-reversal symmetric topological orders are anomalous in that they
cannot be realized in strictly two-dimensions without breaking time reversal
symmetry; instead, they can only be realized on the surface of certain
three-dimensional systems. We propose two quantities, which we call {\it
anomaly indicators}, that can detect if a time-reversal symmetric topological
order is anomalous in this sense. Both anomaly indicators are expressed in
terms of the quantum dimensions, topological spins, and time-reversal
properties of the anyons in the given topological order. The first indicator,
$\eta_2$, applies to bosonic systems while the second indicator, $\eta_f$,
applies to fermionic systems in the DIII class. We conjecture that $\eta_2$,
together with a previously known indicator $\eta_1$, can detect the two known
$\mathbb Z_2$ anomalies in the bosonic case, while $\eta_f$ can detect the
$\mathbb Z_{16}$ anomaly in the fermionic case.


title: A scattering approach to a surface with hyperbolic cusp

abstract:
  Let $X$ be a two-dimensional smooth manifold with boundary $S^{1}$ and
$Y=[1,\infty)\times S^{1}$. We consider a family of complete surfaces arising
by endowing $X\cup_{S^{1}}Y$ with a parameter dependent Riemannian metric, such
that the restriction of the metric to $Y$ converges to the hyperbolic metric as
a limit with respect to the parameter. We describe the associated spectral and
scattering theory of the Laplacian for such a surface. We further show that on
$Y$ the zero $S^{1}$-Fourier coefficient of the generalized eigenfunction of
this Laplacian, as a family with respect to the parameter, approximates in a
certain sense, for large values of the spectral parameter, the zero
$S^{1}$-Fourier coefficient of the generalized eigenfunction of the Laplacian
for the case of a surface with hyperbolic cusp.


title: Sharygin triangles and elliptic curves

abstract:
  The paper is devoted to the description of family of scalene triangles for
which the triangle formed by the intersection points of bisectors with opposite
sides is isosceles. We call them Sharygin triangles. It turns out that they are
parametrized by an open subset of an elliptic curve. Also we prove that there
are infinitely many non-similar integer Sharygin triangles.


title:
Joint CoMP-Cell Selection and Resource Allocation with
  Fronthaul-Constrained C-RAN

abstract:
  Cloud-based Radio Access Network (C-RAN) is a promising architecture for
future cellular networks, in which Baseband Units (BBUs) are placed at a
centralized location, with capacity-constrained fronthaul connected to multiple
distributed Remote Radio Units (RRHs) that are far away from the BBUs. The
centralization of signal processing enables the flexibility for coordinated
multi-point transmission (CoMP) to meet high traffic demand of users. We
investigate how to jointly optimize CoMP-cell selection and base station
resource allocation so as to enhance the quality of service (QoS), subject to
the fronthaul capacity constraint in orthogonal frequency-division multiple
access (OFDMA) based C-RAN. The problem is proved to be NP-hard in this paper.
To deal with the computational complexity, we derive a partial optimality
condition as the foundation for designing a cell-selection algorithm. Besides,
we provide a solution method of the optimum of the time-frequency resource
allocation problem without loss of fairness on the QoS enhancement of all
users. The simulations show good performance of the proposed algorithms for
jointly optimizing the cell selection and resource allocation in a C-RAN, with
respect to QoS.


title: On the nature of periodically pulsating radiation sources

abstract:
  A change in the character of maser generation in a two-level system is found
when the initial population inversion exceeds some threshold value proportional
to the square root of the total number of atoms. Above this threshold, the
number of photons begins to grow exponentially with time and the pulse with
short leading edge and broadened trailing edge is generated. In this work, we
attempt to explain the nature of this threshold. Coherent pulse duration
estimated by its half-width increases significantly with increasing inversion,
if all other parameters are fixed and the absorption is neglected. The
inclusion of the energy loss of photons leads to the fact that the duration of
coherent pulse is almost constant with increasing inversion, at least well away
from the threshold. If there is exist a recovery mechanism for the population
inversion, the pulsating mode of stimulated emission generation becomes
possible. The integral radiation intensity at this may be increased several
times. This approach can be used for analysis of the cosmic radiation that
might help explain a great variety of pulsating radiation sources in space.


title:
DC high voltage to drive helium plasma jet comprised of repetitive
  streamer breakdowns

abstract:
  This paper demonstrates and studies helium atmospheric pressure plasma jet
comprised of series of repetitive streamer breakdowns, which is driven by a
pure DC high voltage (auto-oscillations). Repetition frequency of the
breakdowns is governed by the geometry of discharge electrodes/surroundings and
gas flow rate. Each next streamer is initiated when the electric field on the
anode tip recovers after the previous breakdown and reaches the breakdown
threshold value of about 2.5 kV/cm. Repetition frequency of the streamer
breakdowns excited using this principle can be simply tuned by reconfiguring
the discharge electrode geometry. This custom-designed type of the helium
plasma jet, which operates on the DC high voltage and is comprised of the
series of the repetitive streamer breakdowns at frequency about 13 kHz, is
demonstrated.


title: A Class of Profinite Hopf-Galois Extensions Over Q

abstract:
  For $p$ a prime and $a\in\mathbb{Q}$, where $a$ is not a $p^n$-th power of
any rational number, the extension $\mathbb{Q}(w_n)/\mathbb{Q}$ where
$w_n=\root p^n \of a$ is separable but non-normal. The Hopf-Galois theory for
separable extensions was determined by Greither and Pareigis, and the specific
classification for radical extensions such as these by the author. In this work
we extend this theory to a certain class of profinite extensions, namely those
formed from the union of these $\mathbb{Q}(w_n)$. We construct a 'profinite'
Hopf algebra which acts, and show that it satisfies a generalization of a
result due to Haggenmuller and Pareigis on the structure of Hopf algebra forms
of group algebras.


title:
A Harmonic Mean Linear Discriminant Analysis for Robust Image
  Classification

abstract:
  Linear Discriminant Analysis (LDA) is a widely-used supervised dimensionality
reduction method in computer vision and pattern recognition. In null space
based LDA (NLDA), a well-known LDA extension, between-class distance is
maximized in the null space of the within-class scatter matrix. However, there
are some limitations in NLDA. Firstly, for many data sets, null space of
within-class scatter matrix does not exist, thus NLDA is not applicable to
those datasets. Secondly, NLDA uses arithmetic mean of between-class distances
and gives equal consideration to all between-class distances, which makes
larger between-class distances can dominate the result and thus limits the
performance of NLDA. In this paper, we propose a harmonic mean based Linear
Discriminant Analysis, Multi-Class Discriminant Analysis (MCDA), for image
classification, which minimizes the reciprocal of weighted harmonic mean of
pairwise between-class distance. More importantly, MCDA gives higher priority
to maximize small between-class distances. MCDA can be extended to multi-label
dimension reduction. Results on 7 single-label data sets and 4 multi-label data
sets show that MCDA has consistently better performance than 10 other
single-label approaches and 4 other multi-label approaches in terms of
classification accuracy, macro and micro average F1 score.


title: Electron Doping a Kagome Spin Liquid

abstract:
  Herbertsmithite, ZnCu$_3$(OH)$_6$Cl$_2$, is a two dimensional kagom\'{e}
lattice realization of a spin liquid, with evidence for fractionalized
excitations and a gapped ground state. Such a quantum spin liquid has been
proposed to underlie high temperature superconductivity and is predicted to
produce a wealth of new states, including a Dirac metal at $1/3$rd electron
doping. Here we report the topochemical synthesis of electron-doped
ZnLi$_x$Cu$_3$(OH)$_6$Cl$_2$ from $x$ = 0 to $x$ = 1.8 ($3/5$th per Cu$^{2+}$).
Contrary to expectations, no metallicity or superconductivity is induced.
Instead, we find a systematic suppression of magnetic behavior across the phase
diagram. Our results demonstrate that significant theoretical work is needed to
understand and predict the role of doping in magnetically frustrated narrow
band insulators, particularly the interplay between local structural disorder
and tendency toward electron localization, and pave the way for future studies
of doped spin liquids.


title: Ordinal Notation

abstract:
  We introduce a framework for ordinal notation systems, present a family of
strong yet simple systems, and give many examples of ordinals in these systems.
While much of the material is conjectural, we include systems with conjectured
strength beyond second order arithmetic (and plausibly beyond ZFC), and prove
well-foundedness for some weakened versions.


title: Tensor power of dynamical maps and P- vs. CP-divisibility

abstract:
  The are several non-equivalent notions of Markovian quantum evolution. In
this paper we show that the one based on the so-called CP-divisibility of the
corresponding dynamical map enjoys the following stability property: the
dynamical map $\Lambda_t$ is CP-divisible iff the second tensor power
$\Lambda_t\otimes\Lambda_t$ is CP-divisible as well. Moreover, the
P-divisibility of the map $\Lambda_t\otimes\Lambda_t$ is equivalent to the
CP-divisibility of the map $\Lambda_t$. Interestingly, the latter property is
no longer true if we replace the P-divisibility of $\Lambda_t\otimes\Lambda_t$
by simple positivity and the CP-divisibility of $\Lambda_t$ by complete
positivity. That is, unlike when $\Lambda_t$ has a time-independent generator,
positivity of $\Lambda_t\otimes\Lambda_t$ does not imply complete positivity of
$\Lambda_t$.


title:
The cosmic-ray ground-level enhancements of 29 September 1989 and 20
  January 2005

abstract:
  Enhancements of the comic-ray intensity as observed by detectors on the
ground have been observed 71 times since 1942. They are due to solar energetic
particles accelerated in the regions of solar flares deep in the corona, or in
the shock front of coronal mass ejections (CMEs) in the solar wind. The latter
is the favoured model for the classical gradual ground level enhancement (GLE).
In several papers since the one of McCracken et al. (2008), we pointed out,
however, that some GLEs are too impulsive to be accelerated in the CME shocks.
This hypothesis, together with other properties of GLEs, is demonstrated
graphically in this paper by plotting and comparing the time profiles of GLEs
42 of 29 September 1989 and GLE 69 of 20 January. These two events are
respectively the largest examples of gradual and prompt events.


title:
Improving Server Utilization in a Distributed Computing Set-up with
  Independent Clients

abstract:
  We consider a set-up in which there are multiple servers and multiple clients
in a large distributed computing system. Clients request servers to process
jobs. Servers can only process one job in unit time. There is no coordinating
agent to route client requests to servers, and clients choose servers
independently and simultaneously, and only have access to the outcomes of their
own past requests. If more than one clients choose the same server, then only
one randomly chosen client's requests will be fulfilled. If some servers do not
receive any request, they remain idle. In this paper, we show that a large
category of strategies are not effective in terms of server utilization. We
devise strategies for clients that improve server utilization of such systems
over those of strategies known in the current literature.


title:
Comments on All-electron mixed basis GW calculations of TiO2 and ZnO
  crystals

abstract:
  These brief comments on the article in Phys. Rev. B 93, 155116 (2016),
address an inadvertent misrepresentation of the capabilities of density
functional theory (DFT) and of its local density approximation (LDA) in
describing electronic and related properties of materials accurately. The
oversight of some previous LDA results that agree with experiments partly led
to this unintended misrepresentation, in addition to a few assertions relative
to perceived deficiencies of DFT.


title:
WIYN Open Cluster Study. LXXII. A uvbyCa Hbeta CCD Analysis of the
  Metal-Deficient Open Cluster, NGC 2506

abstract:
  Precision uvbyCa Hbeta photometry of the metal-deficient, old open cluster,
NGC 2506, is presented. The survey covers an area 20 by 20 arcminutes, and
extends to V~18 for b-y and Hbeta and to V~17.0 for c_1 and hk. For V < 16.0,
photometric scatter among the indices leads to the recovery of 6 known
variables within the cluster core and 5 new variables in the outer 5 arcmin of
the survey field. Proper motions, radial velocities, and precise multicolor
indices are used to isolate a highly probable sample of cluster members from
the very rich color-magnitude diagram (CMD). From 257 highly probable members
at the cluster turnoff, we derive a reddening estimate of E(b-y) = 0.042 +/-
0.001 (E(B-V) = 0.058 +/- 0.001), where the errors refer to the internal
standard errors of the mean. [Fe/H] is derived from the A/F dwarf members using
both m_1 and hk, leading to [Fe/H] = -0.296 +/- 0.011 (sem) and -0.317 +/-
0.004 (sem), respectively. The weighted average, heavily dominated by hk, is
[Fe/H] = -0.316 +/- 0.033. Based upon red giant members, we place an upper
limit of +/- 0.010 on the variation in the reddening across the face of the
cluster. We also identify two dozen potential red giant cluster members outside
the cluster core. Victoria-Regina isochrones on the Stromgren system produce an
excellent match to the cluster for an apparent modulus of (m-M) = 12.75 +/- 0.1
and an age of 1.85 +/- 0.05 Gyr.


title:
Infinite Determinantal Measures and The Ergodic Decomposition of
  Infinite Pickrell Measures II. Convergence of determinantal measures

abstract:
  The second part of the paper mainly deals with convergence of infinite
determinantal measures, understood as the convergence of the approximating
finite determinantal measures. In addition to the usual weak topology on the
space of probability measures on the space of configurations, we also consider
the weak topology on the space of finite measures on the space of finite
measures on the half-line, used via the natural immersion, well-defined almost
surely with respect to the infinite Bessel point process, of the space of
configurations into the space of finite measures on the half-line. The main
results of the second part are sufficient conditions for tightness of families
of determinantal measures, for convergence of sequences of induced proceses, as
well as for sequences of finite-dimensional perturbations of determinantal
processes.


title: Wedge Diffraction as an Instance of Radiative Shielding

abstract:
  The celebrated Sommerfeld wedge diffraction solution is reexamined from a
null interior field perspective. Exact surface currents provided by that
solution, when considered as disembodied half-plane laminae radiating into an
ambient, uniform space both inside and outside the wedge proper, do succeed in
reconstituting both a specular, mirror field above the exposed face, and a
shielding plane-wave field of a sign opposite to that of the incoming
excitation which, under superposition, creates both the classical,
geometric-optics shadow, and a strictly null interior field at the dominant,
plane-wave level. Both mirror and shadow radiated fields are controlled by the
residue at just one simple pole encountered during a spectral radiative field
assembly, fixed in place by incidence direction $\phi_{0}$ as measured from the
exposed face. The radiated fields further provide diffractive contributions
drawn from two saddle points that track observation angle $\phi.$ Even these,
more or less asymptotic contributions, are found to cancel exactly within the
wedge interior, while, on the outside, they recover in its every detail the
canonical structure lying at the base of GTD (geometric theory of diffraction).
It is earnestly hoped that this revised scattering viewpoint, while leaving
intact all details of the existing solution, will impart to it a fresh,
physically robust meaning. Moreover, since this viewpoint confirms, admittedly
in an extreme limit, the concept of field self-consistency (Ewald-Oseen
extinction in more picturesque language), perhaps such explicit vindication may
yet encourage efforts to seek exact solutions to scattering/diffraction by
electromagnetically permeable (dielectric) wedges, efforts that harness
integral equations with polarization/ohmic currents distributed throughout
wedge volumes as sources radiating into an ambient, uniform reference medium.


title:
Refinement Reflection (or, how to turn your favorite language into a
  proof assistant using SMT)

abstract:
  Refinement Reflection turns your favorite programming language into a proof
assistant by reflecting the code implementing a user-defined function into the
function's (output) refinement type. As a consequence, at uses of the function,
the function definition is unfolded into the refinement logic in a precise,
predictable and most importantly, programmer controllable way. In the logic, we
encode functions and lambdas using uninterpreted symbols preserving SMT-based
decidable verification. In the language, we provide a library of combinators
that lets programmers compose proofs from basic refinements and function
definitions. We have implemented our approach in the Liquid Haskell system,
thereby converting Haskell into an interactive proof assistant, that we used to
verify a variety of properties ranging from arithmetic properties of higher
order, recursive functions to the Monoid, Applicative, Functor and Monad type
class laws for a variety of instances.


title: Impurity induced current in a Chern insulator

abstract:
  Chern insulators arguably provide the simplest examples of topological
phases. They are characterized by a topological invariant and can be identified
by the presence of protected edge states. In this article, we show that a local
impurity in a Chern insulator induces a twofold response: bound states that
carry a chiral current and a net current circulating around the impurity. This
is a manifestation of broken time symmetry and persists even for an
infinitesimal impurity potential. To illustrate this, we consider a Coulomb
impurity in the Haldane model. Working in the low-energy long-wavelength limit,
we show that an infinitesimal impurity strength suffices to create bound
states. We find analytic wavefunctions for the bound states and show that they
carry a circulating current. In contrast, in the case of a trivial analogue,
graphene with a gap induced by a sublattice potential, bound states occur but
carry no current. In the many body problem of the Haldane model at
half-filling, we use a linear response approach to demonstrate a circulating
current around the impurity. Impurity textures in insulators are generally
expected to decay exponentially; in contrast, this current decays polynomially
with distance from the impurity. Going beyond the Haldane model, we consider
the case of coexisting trivial and non-trivial masses. We find that the
impurity induces a local chiral current as long as time reversal symmetry is
broken. However, the decay of this local current bears a signature of the
overall topology - the current decays polynomially in a non-trivial system and
exponentially in a trivial system. In all cases, our analytic results agree
well with numerical tight-binding simulations.


title:
Arithmetic, Infinite Trees, and Second-order Subsystems: Notes and
  Observations

abstract: Work in progress concerning alternative formalizations of arithmetic.


title:
Joint Transmit Power and Relay Two-Way Beamforming Optimization for
  Energy-Harvesting Full-Duplex Communications

abstract:
  This paper studies the joint optimization problem of two-way relay
beamforming, the receiver power splitting (PS) ratio as well as the transmit
power at the sources to maximize the achievable sum-rate of a simultaneous
wireless information and power transfer (SWIPT) system with a full-duplex (FD)
multiple-input multiple-output (MIMO) amplify and forward (AF) relay, assuming
perfect channel state information (CSI). In particular, our contribution is an
iterative algorithm based on the difference of convex programming (DC) and one
dimensional searching to achieve the joint solution. Simulation results are
provided to demonstrate the effectiveness of the proposed algorithm.


title:
Quasi-perfect absorption by sub-wavelength acoustic panels in
  transmission using accumulation of resonances due to slow sound

abstract:
  We theoretically and experimentally report sub-wavelength resonant panels for
low-frequency quasi-perfect sound absorption including transmission by using
the accumulation of cavity resonances due to the slow sound phenomenon. The
sub-wavelength panel is composed of periodic horizontal slits loaded by
identical Helmholtz resonators (HRs). Due to the presence of the HRs, the
propagation inside each slit is strongly dispersive, with near-zero phase
velocity close to the resonance of the HRs. In this slow sound regime, the
frequencies of the cavity modes inside the slit are down-shifted and the slit
behaves as a subwavelength resonator. Moreover, due to strong dispersion, the
cavity resonances accumulate at the limit of the bandgap below the resonance
frequency of the HRs. Near this accumulation frequency, simultaneously
symmetric and antisymmetric quasi-critical coupling can be achieved. In this
way, using only monopolar resonators quasi-perfect absorption can be obtained
in a material including transmission.


title:
The Ergodic Decomposition of Infinite Pickrell Measures III. The
  infinite Bessel process as the limit of radial parts of finite-dimensional
  projections of infinite Pickrell measures

abstract:
  The third part of the paper concludes the proof of the main result --- the
description of the ergodic decomposition of infinite Pickrell measures. First
it is shown that the scaling limit of radial parts of finite-dimensional
infinite Pickrell measures is precisely the infinite Bessel point process. It
is then established that the "gaussian parameter" almost surely vanishes for
our ergodic components, and the convergence to the scaling limit is then
established in the space of finite measures on the space of finite measures.
Finally, singularity is established for Pickrell measures corresponding to
different values of the parameter.


title:
Coagulation and universal scaling limits for critical Galton-Watson
  processes

abstract:
  The basis of this paper is the elementary observation that the $n$-step
descendant distribution of any Galton-Watson process satisfies a discrete
Smoluchowski coagulation equation with multiple coalescence. Using this we
obtain necessary and sufficient criteria for the convergence of scaling limits
of Galton-Watson processes that are simpler (and equivalent) to the classical
criteria obtained by Grimvall in 1974. Our results provide a clear and natural
interpretation, and an alternate proof, of the fact that the L\'evy jump
measure of certain CSBPs satisfies a generalized Smoluchowski equation. (This
result was previously proved by Bertoin and Le Gall in 2006.)
  Moreover, our analysis shows that the nonlinear scaling dynamics of CSBPs
becomes linear and purely dilatational when expressed in terms of the L\'evy
triple associated with the branching mechanism. We use this to prove existence
of universal critical Galton-Watson and CSBPs analogous to W. Doeblin's
"universal laws". Namely, these universal processes generate all possible
critical and subcritical CSBPs as subsequential scaling limits.
  Our convergence results rely on a natural topology for L\'evy triples and a
continuity theorem for Bernstein transforms (Laplace exponents). We develop
these in a self-contained appendix.


title: Observed periodicity related to the four-strand Burau representation

abstract:
  A long-standing open problem is to determine for which values of n the Burau
representation Psi_n of the braid group B_n is faithful. Following work of
Moody, Long-Paton, and Bigelow, the remaining open case is n = 4. One criterion
states that Psi_n is unfaithful if and only if there exists a pair of arcs in
the n-punctured disk D_n such that a certain associated polynomial is zero. In
this paper, we use a computer search to show that there is no such arc-pair in
D_4 with 2000 or fewer intersections, thus certifying the faithfulness of Psi_4
up to this point. We also investigate the structure of the set of arc-pair
polynomials, observing a striking periodicity that holds between those that
are, in some sense, 'closest' to zero. This is the first instance known to the
authors of a deeper analysis of this polynomial set.


title:
Ground state solutions for fractional scalar field equations under a
  general critical nonlinearity

abstract:
  In this paper we study existence of ground state solution to the following
problem $$ (- \Delta)^{\alpha}u = g(u) \ \ \mbox{in} \ \ \mathbb{R}^{N}, \ \ u
\in H^{\alpha}(\mathbb R^N) $$ where $(-\Delta)^{\alpha}$ is the fractional
Laplacian, $\alpha\in (0,1)$. We treat both cases $N\geq2$ and $N=1$ with
$\alpha=1/2$. The function $g$ is a general nonlinearity of Berestycki-Lions
type which is allowed to have critical growth: polynomial in case $N\geq2$,
exponential if $N=1$.


title:
Reduction of $\mathbb{Z}$ classification of a two-dimensional weak
  topological insulator - real-space DMFT study -

abstract:
  One of the remarkable interaction effects on topological insulators is the
reduction of topological classification in free-fermion systems. We address
this issue in a bilayer honeycomb lattice model by taking into account
temperature effects on the reduction. Our analysis, based on the real-space
dynamical mean field theory, elucidates the following results. (i) Even when
the reduction occurs, the winding number defined by the Green's function can
take a nontrivial value at zero temperature. (ii) The winding number taking the
nontrivial value becomes consistent with the absence of gapless edge modes due
to Mott behaviors emerging only at the edges. (iii) Temperature effects can
restore the gapless edge modes, provided that the energy scale of interactions
is smaller than the bulk gap. In addition, we observe the topological edge Mott
behavior only in some finite temperature region.


title: Quantum and Classical Dynamics of Molecular Scale Structures

abstract:
  In this thesis, I investigate the molecular electronic properties of
molecular junctions formed from single molecules. I started my thesis by
discusses the main theoretical methods using in this work density functional
theory and the green function formalism of electron transport. These two
techniques are used to study the charge transport through dicarboxylic acid
terminated alkanes in chapter 4, with graphene gold nanogap electrodes. The
results are then compared with those using symmetric gold electrodes and reveal
that there is a difference between the two situations due to the difference in
Fermi energies relative to the frontier orbitals of the molecules. Furthermore,
the electrical conductance in the asymmetric junction is higher than that in
the symmetric junction, which suggests that graphene offers superior electrode
performance when utilizing carboxylic acid anchor groups. In chapter 5, I study
affected of the saturated chain conductance by adding oxygen to the chain.
Comparisons between my electronic structure calculations on oligoether chains
and previous work on alkanes show that the conductance of oligoether is lower
than that of alkane chains with the same length. I found that the beta
tunneling factor per methyl unit of the alkanes is lower than the beta factor
of oligoether. In the final chapter, molecular dynamic simulations are used to
examine the molecular assembly of two candidate molecules for graphene-based
molecular electronics, one with one pyrene anchor, Pyrene PEGn exTTF, PPT, and
the other with three pyrene anchors, tri pyrene derivative, TPPT, on a
disordered graphene surface. PPT is seen to form flat structures whilst TPPT is
seen to form semicircular cone like micelle structures on the graphene surface.
In the presence of water, the PPT tends to aggregate whereas the TPPT micelle
expands.


title: Concave-convex effects for critical quasilinear elliptic problems

abstract:
  It is established existence, multiplicity and asymptotic behavior of positive
solutions for a quasilinear elliptic problem driven by the $\Phi$-Laplacian
operator. One of these solutions is obtained as ground state solution by
applying the well known Nehari method. The semilinear term in the quasilinear
equation is a concave-convex function which presents a critical behavior at
infinity. The concentration compactness principle is used in order to recover
the compactness required in variational methods.


title:
Thermal Properties and an Improved Shape Model for Near-Earth Asteroid
  (162421) 2000 ET70

abstract:
  We present thermal properties and an improved shape model for potentially
hazardous asteroid (162421) 2000 ET70. In addition to the radar data from 2000
ET70's apparition in 2012, our model incorporates optical lightcurves and
infrared spectra that were not included in the analysis of Naidu et al. (2013,
Icarus 226, 323-335). We confirm the general "clenched fist" appearance of the
Naidu et al. model, but compared to their model, our best-fit model is about
10% longer along its long principal axis, nearly identical along the
intermediate axis, and about 25% shorter along the short axis. We find the
asteroid's dimensions to be 2.9 km $\times$ 2.2 km $\times$ 1.5 km (with
relative uncertainties of about 10%, 15%, and 25%, respectively). With the
available data, 2000 ET70's period and pole position are degenerate with each
other. The radar and lightcurve data together constrain the pole direction to
fall along an arc that is about twenty-three degrees long and eight degrees
wide. Infrared spectra from the NASA InfraRed Telescope Facility (IRTF) provide
an additional constraint on the pole. Thermophysical modeling, using our
SHERMAN software, shows that only a subset of the pole directions, about twelve
degrees of that arc, are compatible with the infrared data. Using all of the
available data, we find that 2000 ET70 has a sidereal rotation period of 8.944
hours ($\pm$ 0.009 h) and a north pole direction of ecliptic coordinates
$(52^{\circ}, -60^{\circ}) \pm 6^{\circ}$. The infrared data, acquired over
several dates, require that the thermal properties (albedo, thermal inertia,
surface roughness) must change across the asteroid's surface. By incorporating
the detailed shape model and spin state into our thermal modeling, the multiple
ground-based observations at different viewing geometries have allowed us to
constrain the levels of the variations in the surface properties.


title: Hirzebruch functional equations and complex Krichever genera

abstract:
  It is well known that the two-parametric Todd genus and elliptic functions of
level $d$ define $n$-multiplicative Hirzebruch genera, if $d$ divides $n+1$.
Both these cases are particular cases of Krichever genera defined by the
Baker--Akhiezer functions. In this work the inverse problem is solved. Namely,
it is proved that only these families of functions define $n$-multiplicative
Hirzebruch genera among all the Krichever genera for all $n$.


title:
SPARSE: A Subgrid Particle Averaged Reynolds Stress Equivalent Model:
  Testing with A Priori Closure

abstract:
  A Lagrangian particle cloud model is proposed that accounts for the effects
of Reynolds-averaged particle and turbulent stresses and the averaged
carrier-phase velocity of the sub-particle-cloud scale on the averaged motion
and velocity of the cloud. The SPARSE (Subgrid Particle Average Reynolds Stress
Equivalent) model is based on a combination of a truncated Taylor expansion of
a drag correction function and Reynolds averaging. It reduces the required
number of computational parcels to trace a cloud of particles in
Eulerian-Lagrangian methods for the simulation of particle-laden flow. Closure
is performed in an a priori manner using a reference simulation where all
particles in the cloud are traced individually with a point particle model.
Comparison of a first-order model and SPARSE with the reference simulation in
one-dimension shows that both the stress and the averaging of the carrier-phase
velocity on the cloud subscale affect the averaged motion of the particle. A
three-dimensional isotropic turbulence computation shows that only one
computational parcel is sufficient to accurately trace a cloud of tens of
thousand of particles.


title:
Giant Hub Src and Syk Tyrosine Kinase Thermodynamic Profiles
  Recapitulate Evolution

abstract:
  Thermodynamic scaling theory, previously applied mainly to small proteins,
here analyzes quantitative evolution of the titled functional network giant hub
enzymes. The broad domain structure identified homologically is confirmed
hydropathically using amino acid sequences only. The most surprising results
concern the evolution of the tyrosine kinase globular surface roughness from
avian to mammals, which is first order, compared to the evolution within
mammals from rodents to humans, which is second order. The mystery of the
unique amide terminal region of proto oncogene tyrosine protein kinase is
resolved by the discovery there of a septad targeting cluster, which is
paralleled by an octad catalytic cluster in tyrosine kinase in humans and a few
other species. These results, which go far towards explaining why these
proteins are among the largest giant hubs in protein interaction networks, use
no adjustable parameters.


title:
Comments on All-electron self-consistent GW in the Matsubara-time
  domain: Implementation and benchmarks of semiconductors and insulators

abstract:
  Chu et al. recently reported extensive results of local density approximation
(LDA) and of four (4) different Green function and dressed Coulomb (GW)
approximation calculations of electronic properties of several semiconductors
and insulators [Phys. Rev. B 93, 125210 (2016)].


title:
Simultaneous Learning of Trees and Representations for Extreme
  Classification and Density Estimation

abstract:
  We consider multi-class classification where the predictor has a hierarchical
structure that allows for a very large number of labels both at train and test
time. The predictive power of such models can heavily depend on the structure
of the tree, and although past work showed how to learn the tree structure, it
expected that the feature vectors remained static. We provide a novel algorithm
to simultaneously perform representation learning for the input data and
learning of the hierarchi- cal predictor. Our approach optimizes an objec- tive
function which favors balanced and easily- separable multi-way node partitions.
We theoret- ically analyze this objective, showing that it gives rise to a
boosting style property and a bound on classification error. We next show how
to extend the algorithm to conditional density estimation. We empirically
validate both variants of the al- gorithm on text classification and language
mod- eling, respectively, and show that they compare favorably to common
baselines in terms of accu- racy and running time.


title: Cauchy Identities for the Characters of the Compact Classical Groups

abstract:
  Motivated by statistical applications, this paper introduces Cauchy
identities for characters of the compact classical groups. These identities
generalize the well-known Cauchy identity for characters of the unitary group,
which are Schur functions of symmetric function theory. Application to
statistical hypothesis testing is briefly sketched.


title: A Distributed Parallel Algorithm for Minimum Spanning Tree Problem

abstract:
  In this paper we present and evaluate a parallel algorithm for solving a
minimum spanning tree (MST) problem for supercomputers with distributed memory.
The algorithm relies on the relaxation of the message processing order
requirement for one specific message type compared to the original GHS
(Gallager, Humblet, Spira) algorithm. Our algorithm adopts hashing and message
compression optimization techniques as well. To the best of our knowledge, this
is the first parallel implementation of the GHS algorithm that linearly scales
to more than 32 nodes (256 cores) of Infiniband cluster.


title:
Multiple Emitters in a Waveguide: Non-Reciprocity and Correlated Photons
  at Perfect Elastic Transmission

abstract:
  We investigate interference and correlation effects when several detuned
emitters are placed along a one-dimensional photonic waveguide. Such a setup
allows multiple interactions between the photons and the strongly coupled
emitters, and underlies proposed devices for quantum information processing. We
show, first, that a pair of detuned two-level systems (2LS) separated by a half
wavelength mimic a driven {\Lambda}-type three-level system (3LS) in both the
single- and two- photon sectors. There is an interference-induced transparency
peak at which the fluorescence is quenched, leaving the transmitted photons
completely uncorrelated. Slightly away from this separation, we find that the
inelastic scattering (fluorescence) is large, leading to nonlinear effects such
as non-reciprocity (rectification). We connect this non-reciprocity to
inelastic scattering caused by driving a dark pole and so derive a condition
for maximum rectification. Finally, by placing a true 3LS midway between the
two 2LS, we show that elastic scattering produces only transmission, but
inelastic scattering nevertheless occurs (the fluorescence is not quenched)
causing substantial photon correlations.


title: Deep Learning Ensembles for Melanoma Recognition in Dermoscopy Images

abstract:
  Melanoma is the deadliest form of skin cancer. While curable with early
detection, only highly trained specialists are capable of accurately
recognizing the disease. As expertise is in limited supply, automated systems
capable of identifying disease could save lives, reduce unnecessary biopsies,
and reduce costs. Toward this goal, we propose a system that combines recent
developments in deep learning with established machine learning approaches,
creating ensembles of methods that are capable of segmenting skin lesions, as
well as analyzing the detected area and surrounding tissue for melanoma
detection. The system is evaluated using the largest publicly available
benchmark dataset of dermoscopic images, containing 900 training and 379
testing images. New state-of-the-art performance levels are demonstrated,
leading to an improvement in the area under receiver operating characteristic
curve of 7.5% (0.843 vs. 0.783), in average precision of 4% (0.649 vs. 0.624),
and in specificity measured at the clinically relevant 95% sensitivity
operating point 2.9 times higher than the previous state-of-the-art (36.8%
specificity compared to 12.5%). Compared to the average of 8 expert
dermatologists on a subset of 100 test images, the proposed system produces a
higher accuracy (76% vs. 70.5%), and specificity (62% vs. 59%) evaluated at an
equivalent sensitivity (82%).


title:
Definition of fractional Laplacian for functions with polynomial
  growth\tha

abstract:
  We introduce a notion of fractional Laplacian for functions which grow more
than linearly at infinity. In such case, the operator is not defined in the
classical sense: nevertheless, we can give an ad-hoc definition which can be
useful for applications in various fields, such as blowup and free boundary
problems.
  In this setting, when the solution has a polynomial growth at infinity, the
right hand side of the equation is not just a function, but an equivalence
class of functions modulo polynomials of a fixed order.
  We also give a sharp version of the Schauder estimates in this framework, in
which the full smooth H\"older norm of the solution is controlled in terms of
the seminorm of the nonlinearity.
  Though the method presented is very general and potentially works for general
nonlocal operators, for clarity and concreteness we focus here on the case of
the fractional Laplacian.


title: Acoustic vibration problem for dissipative fluids

abstract:
  In this paper we analyze a finite element method for solving a quadratic
eigenvalue problem derived from the acoustic vibration problem for a
heterogeneous dissipative fluid. The problem is shown to be equivalent to the
spectral problem for a noncompact operator and athorough spectral
characterization is given. The numerical discretization of the problem is based
on Raviart-Thomas finite elements. The method is proved to be free of spurious
modes and to converge with optimal order. Finally, we report numerical tests
which allow us to assess the performance of the method.


title: Quantum entanglement for two qubits in a nonstationary cavity

abstract:
  The quantum entanglement and the probability of the dynamical Lamb effect for
two qubits caused by non-adiabatic fast change of the boundary conditions are
studied. The conditional concurrence of the qubits for each fixed number of
created photons in a nonstationary cavity is obtained as a measure of the
dynamical quantum entanglement due to the dynamical Lamb effect. We discuss the
physical realization of the dynamical Lamb effect, based on superconducting
qubits.


title: High Power Polarized Positron Source

abstract:
  We discuss the basis of polarized positron production by low energy polarized
electrons. Efficiency of conversion ~0.1-1% might be interesting for CEBAF
facility and ILC as well.


title: Toric surfaces with equivariant Kazhdan-Lusztig atlases

abstract:
  A Kazhdan-Lusztig atlas, introduced by He, Knutson and Lu, on a stratified
variety (V,Y) is a way of modeling the stratification Y of V locally on the
stratification of Kazhdan-Lusztig varieties X^w_o \cap X_v by their
intersection with opposite Schubert varieties X_u. We are interested in
classifying smooth toric surfaces with Kazhdan-Lusztig atlases. This involves
finding a degeneration of V to a union of Richardson varieties in the flag
variety H/B_H of some Kac-Moody group H. We determine which toric surfaces have
a chance at having a Kazhdan-Lusztig atlas by looking at their moment
polytopes, then describe a way to find a suitable group H. More precisely, we
find that (up to equivalence) there are 19 or 20 broken toric surfaces
admitting simply-laced atlases, and that there are at most 7543 broken toric
surfaces where H is any Kac-Moody group.


title: A Closed Form Solution to Multi-View Low-Rank Regression

abstract:
  Real life data often includes information from different channels. For
example, in computer vision, we can describe an image using different image
features, such as pixel intensity, color, HOG, GIST feature, SIFT features,
etc.. These different aspects of the same objects are often called multi-view
(or multi-modal) data. Low-rank regression model has been proved to be an
effective learning mechanism by exploring the low-rank structure of real life
data. But previous low-rank regression model only works on single view data. In
this paper, we propose a multi-view low-rank regression model by imposing
low-rank constraints on multi-view regression model. Most importantly, we
provide a closed-form solution to the multi-view low-rank regression model.
Extensive experiments on 4 multi-view datasets show that the multi-view
low-rank regression model outperforms single-view regression model and reveals
that multi-view low-rank structure is very helpful.


title: Szeg\H{o} kernel asymptotic expansion on CR manifolds with $S^1$ action

abstract:
  Let $X$ be a compact connected strongly pseudoconvex CR manifold of dimension
$2n+1, n \ge 1$ with a transversal CR $S^1$ action on $X$. We establish an
asymptotic expansion for the $m$-th Fourier component of the Szeg\H{o} kernel
function as $m\rightarrow\infty$, where the expansion involves a contribution
in terms of a distance function from lower dimensional strata of the $S^1$
action. We also obtain explicit formulas for the first three coefficients of
the expansion.


title: New Hardness Results for the Permanent Using Linear Optics

abstract:
  In 2011, Aaronson gave a striking proof, based on quantum linear optics,
showing that the problem of computing the permanent of a matrix is #P-hard.
Aaronson's proof led naturally to hardness of approximation results for the
permanent, and it was arguably simpler than Valiant's seminal proof of the same
fact in 1979. Nevertheless, it did not prove that computing the permanent was
#P-hard for any class of matrices which was not previously known. In this
paper, we present a collection of new results about matrix permanents that are
derived primarily via these linear optical techniques.
  First, we show that the problem of computing the permanent of a real
orthogonal matrix is #P-hard. Much like Aaronson's original proof, this will
show that even a multiplicative approximation remains #P-hard to compute. The
hardness result even translates to permanents over finite fields, where the
problem of computing the permanent of an orthogonal matrix is ModpP-hard in the
finite field F_{p^4} for all primes p not equal to 2 or 3. Interestingly, this
characterization is tight: in fields of characteristic 2, the permanent
coincides with the determinant; in fields of characteristic 3, one can
efficiently compute the permanent of an orthogonal matrix by a nontrivial
result of Kogan.
  Finally, we use more elementary arguments to prove #P-hardness for the
permanent of a positive semidefinite matrix, which shows that certain
probabilities of boson sampling experiments with thermal states are hard to
compute exactly despite the fact that they can be efficiently sampled by a
classical computer.


title:
Measurement of the optical dielectric function of transition metal
  dichalcogenide monolayers: MoS2, MoSe2, WS2 and WSe2

abstract:
  We report a determination of the complex in-plane dielectric function of
monolayers of four transition metal dichalcogenides: MoS2, MoSe2, WS2 and WSe2,
for photon energies from 1.5 - 3 eV. The results were obtained from reflection
spectra using a Kramers-Kronig constrained variational analysis. From the
dielectric functions, we obtain the absolute absorbance of the monolayers. We
also provide a comparison of the dielectric function for the monolayers with
the corresponding bulk materials.


title: A non-backtracking Polya's theorem

abstract:
  P\'olya's random walk theorem states that a random walk on a $d$-dimensional
grid is recurrent for $d=1,2$ and transient for $d\ge3$. We prove a version of
P\'olya's random walk theorem for non-backtracking random walks. Namely, we
prove that a non-backtracking random walk on a $d$-dimensional grid is
recurrent for $d=2$ and transient for $d=1$, $d\ge3$. Along the way, we prove
several useful general facts about non-backtracking random walks on graphs. In
addition, our proof includes an exact enumeration of the number of closed
non-backtracking random walks on an infinite 2-dimensional grid. This
enumeration suggests an interesting combinatorial link between non-backtracking
random walks on grids, and trinomial coefficients.


title: Road Curb Extraction from Mobile LiDAR Point Clouds

abstract:
  Automatic extraction of road curbs from uneven, unorganized, noisy and
massive 3D point clouds is a challenging task. Existing methods often project
3D point clouds onto 2D planes to extract curbs. However, the projection causes
loss of 3D information which degrades the performance of the detection. This
paper presents a robust, accurate and efficient method to extract road curbs
from 3D mobile LiDAR point clouds. Our method consists of two steps: 1)
extracting the candidate points of curbs based on the proposed novel energy
function and 2) refining the candidate points using the proposed least cost
path model. We evaluated our method on a large-scale of residential area
(16.7GB, 300 million points) and an urban area (1.07GB, 20 million points)
mobile LiDAR point clouds. Results indicate that the proposed method is
superior to the state-of-the-art methods in terms of robustness, accuracy and
efficiency. The proposed curb extraction method achieved a completeness of
78.62% and a correctness of 83.29%. These experiments demonstrate that the
proposed method is a promising solution to extract road curbs from mobile LiDAR
point clouds.


title:
Finite-sum Composition Optimization via Variance Reduced Gradient
  Descent

abstract:
  The stochastic composition optimization proposed recently by Wang et al.
[2014] minimizes the objective with the compositional expectation form:
$\min_x~(\mathbb{E}_iF_i \circ \mathbb{E}_j G_j)(x).$ It summarizes many
important applications in machine learning, statistics, and finance. In this
paper, we consider the finite-sum scenario for composition optimization:
\[\min_x f (x) := \frac{1}{n} \sum_{i = 1}^n F_i \left(\frac{1}{m} \sum_{j =
1}^m G_j (x) \right). \] We propose two algorithms to solve this problem by
combining the stochastic compositional gradient descent (SCGD) and the
stochastic variance reduced gradient (SVRG) technique. A constant linear
convergence rate is proved for strongly convex optimization, which
substantially improves the sublinear rate $O(K^{-0.8})$ of the best known
algorithm.


title:
On nodes of small degrees and degree profile in preferential dynamic
  attachment circuits

abstract:
  We investigate the joint distribution of nodes of small degrees and the
degree profile in preferential dynamic attachment circuits. In particular, we
study the joint asymptotic distribution of the number of the nodes of outdegree
$0$ (terminal nodes) and outdegree $1$ in a very large circuit. The expectation
and variance of the number of those two types of nodes are both asymptotically
linear with respect to the age of the circuit. We show that the numbers of
nodes of outdegree $0$ and $1$ asymptotically follow a two-dimensional Gaussian
law via multivariate martingale methods. We also study the exact distribution
of the degree of a node, as the circuit ages, via a series of
P\'olya-Eggenberger urn models with "hiccups" in between. The exact expectation
and variance of the degree of nodes are determined by recurrence methods. Phase
transitions of these degrees are discussed briefly. This is an extension of the
abstract [20].


title:
Analysis and Modeling of Social Influence in High Performance Computing
  Workloads

abstract:
  Social influence among users (e.g., collaboration on a project) creates
bursty behavior in the underlying high performance computing (HPC) workloads.
Using representative HPC and cluster workload logs, this paper identifies,
analyzes, and quantifies the level of social influence across HPC users. We
show the existence of a social graph that is characterized by a pattern of
dominant users and followers. This pattern also follows a power-law
distribution, which is consistent with those observed in mainstream social
networks. Given its potential impact on HPC workloads prediction and
scheduling, we propose a fast-converging, computationally-efficient online
learning algorithm for identifying social groups. Extensive evaluation shows
that our online algorithm can (1) quickly identify the social relationships by
using a small portion of incoming jobs and (2) can efficiently track group
evolution over time.


title:
Correcting Type Ia Supernova Distances for Selection Biases and
  Contamination in Photometrically Identified Samples

abstract:
  We present a new technique to create a bin-averaged Hubble Diagram (HD) from
photometrically identified SN~Ia data. The resulting HD is corrected for
selection biases and contamination from core collapse (CC) SNe, and can be used
to infer cosmological parameters. This method, called "BBC" (BEAMS with Bias
Corrections), includes two fitting stages. The first BBC fitting stage uses a
posterior distribution that includes multiple SN likelihoods, a Monte Carlo
simulation to bias-correct the fitted SALT-II parameters, and CC probabilities
determined from a machine learning technique. The BBC fit determines 1) a
bin-averaged HD (average distance vs. redshift), and 2) the nuisance parameters
alpha and beta, which multiply the stretch and color (respectively) to
standardize the SN brightness. In the second stage, the bin-averaged HD is fit
to a cosmological model where priors can be imposed. We perform high precision
tests of the BBC method by simulating large (150,000 event) data samples
corresponding to the Dark Energy Survey Supernova Program. Our tests include
three models of intrinsic scatter, each with two different CC rates. In the BBC
fit, the SALT-II nuisance parameters alpha and beta are recovered to within 1%
of their true values. In the cosmology fit, we determine the dark energy
equation of state parameter w using a fixed value of Omega_matter as a prior:
averaging over all six tests based on 6 x 150,000 = 900,000 SNe, there is a
small w-bias of 0.006 +- 0.002. Finally, the BBC fitting code is publicly
available in the SNANA package.


title: A spacetime DPG method for the Schrodinger equation

abstract:
  A spacetime Discontinuous Petrov Galerkin (DPG) method for the linear
time-dependent Schrodinger equation is proposed. The spacetime approach is
particularly attractive for capturing irregular solutions. Motivated by the
fact that some irregular Schrodinger solutions cannot be solutions of certain
first order reformulations, the proposed spacetime method uses the second order
Schrodinger operator. Two variational formulations are proved to be well-posed:
a strong formulation (with no relaxation of the original equation) and a weak
formulation (also called the ultraweak formulation, that transfers all
derivatives onto test functions). The convergence of the DPG method based on
the ultraweak formulation is investigated using an interpolation operator. A
standalone appendix analyzes the ultraweak formulation for general differential
operators. Reports of numerical experiments motivated by pulse propagation in
dispersive optical fibers are also included.


title:
Symmetry protected line nodes in non-symmorphic magnetic space groups:
  Applications to UCoGe and UPd$_2$Al$_3$

abstract:
  We present the group-thoretical classification of gap functions in
superconductors coexisting with some magnetic order in non-symmorphic magnetic
space groups. Based on the weak-coupling BCS theory, we show that UCoGe-type
ferromagnetic superconductors must have horizontal line nodes on either $k_z=0$
or $\pm\pi/c$ plane. Moreover, it is likely that additional Weyl point nodes
exist at the axial point. On the other hand, in UPd$_2$Al$_3$-type
antiferromagnetic superconductors, gap functions with $A_g$ symmetry possess
horizontal line nodes in antiferromagnetic Brillouin zone boundary
perpendicular to $c$-axis. In other words, the conventional fully-gapped
$s$-wave superconductivity is forbidden in this type of antiferromagnetic
superconductors, irrelevant to the pairing mechanism, as long as the Fermi
surface crosses a zone boundary. UCoGe and UPd$_2$Al$_3$ are candidates for
unconventional superconductors possessing hidden symmetry-protected line nodes,
peculiar to non-symmorphic magnetic space groups.


title: How efficiently can one untangle a double-twist? Waving is believing!

abstract:
  It has long been known to mathematicians and physicists that while a full
rotation in three-dimensional Euclidean space causes tangling, two rotations
can be untangled. Formally, an untangling is a based nullhomotopy of the
double-twist loop in the special orthogonal group of rotations. We study a
particularly simple, geometrically defined untangling procedure, leading to new
conclusions regarding the minimum possible complexity of untanglings. We
animate and analyze how our untangling operates on frames in 3-space, and teach
readers in a video how to wave the nullhomotopy with their hands.


title: Distributed Optimal Gas-Power Flow Using Convex Optimization and ADMM

abstract:
  This paper proposes a convex optimization based distributed algorithm to
solve multi-period optimal gas-power flow (OGPF) in coupled energy distribution
systems. At the gas distribution system side, the non-convex Weymouth gas flow
equations is convexified as quadratic constraints. The optimal gas flow (OGF)
subproblem is solved by an iterative second-order cone programming procedure,
whose efficiency is two orders of magnitudes higher than traditional nonlinear
methods. A convex quadratic program based initiation scheme is suggested, which
helps to find a high-quality starting point. At the power distribution system
side, convex relaxation is performed on the non-convex branch flow equations,
and the optimal power flow (OPF) subproblem gives rise to a second order cone
program. Tightness is guaranteed by the radial topology. In the proposed
distributed algorithm, OGF and OPF are solved independently, and coordinated by
the alternating direction multiplier method (ADMM). Numerical results
corroborate significant enhancements on computational robustness and efficiency
compared with existing centralized OGPF methods.


title: Tests of Lorentz symmetry in the gravitational sector

abstract:
  Lorentz symmetry is one of the pillars of both General Relativity and the
Standard Model of particle physics. Motivated by ideas about quantum gravity,
unification theories and violations of CPT symmetry, a significant effort has
been put the last decades into testing Lorentz symmetry. This review focuses on
Lorentz symmetry tests performed in the gravitational sector. We briefly review
the basics of the pure gravitational sector of the Standard-Model Extension
(SME) framework, a formalism developed in order to systematically parametrize
hypothetical violations of the Lorentz invariance. Furthermore, we discuss the
latest constraints obtained within this formalism including analyses of the
following measurements: atomic gravimetry, Lunar Laser Ranging, Very Long
Baseline Interferometry, planetary ephemerides, Gravity Probe B, binary
pulsars, high energy cosmic rays,... In addition, we propose a combined
analysis of all these results. We also discuss possible improvements on current
analyses and present some sensitivity analyses for future observations.


title: Escape of mass and entropy for geodesic flows

abstract:
  In this paper we study the ergodic theory of the geodesic flow on negatively
curved geometrically finite manifolds. We prove that the measure theoretic
entropy is upper semicontinuous when there is no loss of mass. In case we are
losing mass, the critical exponents of parabolic subgroups of the fundamental
group have a significant meaning. More precisely, the failure of
upper-semicontinuity of the entropy is determinated by the maximal parabolic
critical exponent. We also study the pressure of positive H\"older continuous
potentials going to zero through the cusps. We prove that the pressure map
$t\mapsto P(tF)$ is differentiable until it undergoes a phase transition, after
which it becomes constant. This description allows, in particular, to compute
the entropy at infinity of the geodesic flow.


title:
A study of adatom ripening on an Al (111) surface with machine learning
  force fields

abstract:
  Surface phenomena are increasingly becoming important in exploring nanoscale
materials growth and characterization. Consequently, the need for atomistic
based simulations is increasing. Nevertheless, relying entirely on quantum
mechanical methods limits the length and time scales one can consider,
resulting in an ever increasing dependence on alternative machine learning
based force fields. Recently, we proposed a machine learning approach, known as
AGNI, that allows fast and accurate atomic force predictions given the atom's
neighborhood environment. Here, we make use of such force fields to study and
characterize the nanoscale diffusion and growth processes occurring on an Al
(111) surface. In particular we focus on the adatom ripening phenomena,
confirming past experimental findings, wherein a low and high temperature
growth regime were observed, using entirely molecular dynamics simulations.


title:
On the Diversity of Compact Objects within Supernova Remnants II: Energy
  Loss Mechanisms

abstract:
  Energy losses from isolated neutron stars are commonly attributed to the
emission of electromagnetic radiation from a rotating point-like magnetic
dipole in vacuum. This emission mechanism predicts a braking index $n=3$, which
is not observed in highly magnetized neutron stars. Despite this fact, the
assumptions of a dipole field and rapid early rotation are often assumed a
priori, typically causing a discrepancy between the characteristic age and the
associated supernova remnant (SNR) age. We focus on neutron stars with
`anomalous' magnetic fields that have established SNR associations and known
ages. Anomalous X-ray pulsars (AXPs) and soft gamma repeaters (SGRs) are
usually described in terms of the magnetar model, which posits a large magnetic
field established by dynamo action. The high magnetic field pulsars (HBPs) have
extremely large magnetic fields just above QED scale (but below that of the
AXPs and SGRs), and central compact objects (CCOs) may have buried fields that
will emerge in the future as nascent magnetars. In the first part of this
series we examined magnetic field growth as a method of uniting the CCOs with
HBPs and X-ray dim isolated neutron stars (XDINSs) through evolution. In this
work we constrain the characteristic age of these neutron stars using the
related SNR age for a variety of energy loss mechanisms and allowing for
arbitrary initial spin periods. In addition to the SNR age, we also make use of
the observed braking indices and X-ray luminosities to constrain the models.


title: On the Stability of Kalman-Bucy Diffusion Processes

abstract:
  The Kalman-Bucy filter is the optimal state estimator for an
Ornstein-Uhlenbeck diffusion given that the system is partially observed via a
linear diffusion-type (noisy) sensor. Under Gaussian assumptions, it provides a
finite-dimensional exact implementation of the optimal Bayes filter. It is
generally the only such finite-dimensional exact instance of the Bayes filter
for continuous state-space models. Consequently, this filter has been studied
extensively in the literature since the seminal 1961 paper of Kalman and Bucy.
The purpose of this work is to review, re-prove and refine existing results
concerning the dynamical properties of the Kalman-Bucy filter so far as they
pertain to filter stability and convergence. The associated differential matrix
Riccati equation is a focal point of this study with a number of bounds,
convergence, and eigenvalue inequalities rigorously proven. New results are
also given in the form of exponential and comparison inequalities for both the
filter and the Riccati flow.


title:
Translation and Rotation of Transformation Media under Electromagnetic
  Pulse

abstract:
  It is well known that optical media create artificial geometry for light, and
curved geometry acts as an effective optical medium. This correspondence
originates from the form invariance of Maxwells equations, which recently has
spawned a booming field called transformation optics. Here we investigate
responses of three transformation media under electromagnetic pulses, and find
that pulse radiation can induce unbalanced net force on transformation media,
which will cause translation and rotation of transformation media although
their final momentum can still be zero. Therefore, the transformation media do
not necessarily stay the same after an electromagnetic wave passes through.


title: ExpressPass: End-to-End Credit-based Congestion Control for Datacenters

abstract:
  As link speeds increase in datacenter networks, existing congestion control
algorithms become less effective in providing fast convergence. TCP-based
algorithms that probe for bandwidth take a long time to reach the fair-share
and lead to long flow completion times. An ideal congestion control algorithms
for datacenter must provide 1) zero data loss, 2) fast convergence, and 3) low
buffer occupancy. However, these requirements present conflicting goals. For
fast convergence,flows must ramp up quickly, but this risks packet losses and
large queues. Thus, even the state-of-the-art algorithms, such as TIMELY and
DCQCN, rely on link layer flow control (e.g.,Priority-based Flow Control) to
achieve zero loss. This paper presents a new approach, called ExpressPass, an
end-to-end credit-based congestion control algorithm for datacenters.
ExpressPass is inspired by credit-based flow control, but extends it to work
end-to-end. The switches control the amount of credit packets by rate limiting
and ensure data packets flow in the reverse direction without any loss.
ExpressPass leverages this to ramp up aggressively. ExpressPass converges up to
80 times faster than DCTCP at 10Gbps link, and the gap increases as link speeds
become faster. Our simulation with realistic workload shows that ExpressPass
significantly reduces the flow completion time especially for small and medium
size flows compared to DCTCP, HULL, and DX.


title: Discovery of RR Lyrae Stars in the Nuclear Bulge of the Milky Way

abstract:
  Galactic nuclei, like the one of the Milky Way, are extreme places with high
stellar densities and, in most cases, hosting a supermassive black hole. One of
the scenarios proposed for the formation of the Galactic nucleus is by merging
of primordial globular clusters (Capuzzo-Dolcetta 1993). An implication of this
model is that this region should host stars characteristically found in old
Milky Way globular clusters. RR Lyrae stars are primary distance indicators,
well known representatives of old and metal-poor stellar populations, and
therefore regularly found in globular clusters. Here we report the discovery of
a dozen RR Lyrae ab-type stars in the vicinity of the Galactic center, i.e. in
the so-called nuclear stellar bulge of the Milky Way. This discovery provides
the first direct observational evidence that the Galactic nuclear stellar bulge
contains ancient stars (>10 Gyr old). Based on this we conclude that merging
globular clusters likely contributed to building-up the high stellar density in
the nuclear stellar bulge of the Milky Way.


title: Negative Circles in Signed Graphs: A Problem Collection

abstract:
  I propose that most problems about circles (cycles, circuits) in ordinary
graphs that have odd or even length find their proper setting in the theory of
signed graphs, where each edge has a sign, $+$ or $-$. Even-circle and
odd-circle problems correspond to questions about positive and negative circles
in signed graphs. (The sign of a circle is the product of its edge signs.) I
outline questions about circles in signed graphs, that seem natural and
potentially important.


title: Forbidden Induced Subgraphs

abstract:
  In descending generality I survey: five partial orderings of graphs, the
induced-subgraph ordering, and examples like perfect, threshold, and mock
threshold graphs. The emphasis is on how the induced subgraph ordering differs
from other popular orderings and leads to different basic questions.


title:
Bright Room-Temperature Single Photon Emission from Defects in Gallium
  Nitride

abstract:
  Single photon emitters play a central role in many photonic quantum
technologies. A promising class of single photon emitters consists of atomic
color centers in wide-bandgap crystals, such as diamond silicon carbide and
hexagonal boron nitride. However, it is currently not possible to grow these
materials as sub-micron thick films on low-refractive index substrates, which
is necessary for mature photonic integrated circuit technologies. Hence, there
is great interest in identifying quantum emitters in technologically mature
semiconductors that are compatible with suitable heteroepitaxies. Here, we
demonstrate robust single photon emitters based on defects in gallium nitride
(GaN), the most established and well understood semiconductor that can emit
light over the entire visible spectrum. We show that the emitters have
excellent photophysical properties including a brightness in excess of 500x10^3
counts/s. We further show that the emitters can be found in a variety of GaN
wafers, thus offering reliable and scalable platform for further technological
development. We propose a theoretical model to explain the origin of these
emitters based on cubic inclusions in hexagonal gallium nitride. Our results
constitute a feasible path to scalable, integrated on-chip quantum technologies
based on GaN.


title:
Thick-target transmission method for excitation functions of interaction
  cross sections

abstract:
  We propose a method, called as thick-target transmission (T3) method, to
obtain an excitation function of interaction cross sections. In an ordinal
experiment to measure the excitation function of interaction cross sections by
the transmission method, we need to change the beam energy for each cross
section. In the T3 method, the excitation function is derived from the beam
attenuations measured at the targets of different thicknesses without changing
the beam energy. The advantage of the T3 method is the simplicity and
availability for radioactive beams. To confirm the availability, we perform a
simulation for the 12C+27Al system with the PHITS code instead of actual
experiments. Our results have large uncertainties but well reproduce the
tendency of the experimental data.