title:
Impact of baryonic streaming velocities on the formation of supermassive
  black holes via direct collapse

abstract:
  Baryonic streaming motions produced prior to the epoch of recombination
became supersonic during the cosmic dark ages. Various studies suggest that
such streaming velocities change the halo statistics and also influence the
formation of Population III stars. In this study, we aim to explore the impact
of streaming velocities on the formation of supermassive black holes at $z>10$
via the direct collapse scenario. To accomplish this goal, we perform
cosmological large eddy simulations for two halos of a few times $\rm 10^{7}
M_{\odot}$ with initial streaming velocities of 3, 6 and 9 $\rm km/s$. These
massive primordial halos illuminated by the strong Lyman Werner flux are the
potential cradles for the formation of direct collapse seed black holes. To
study the evolution for longer times, we employ sink particles and track the
accretion for 10,000 years. Our findings show that higher streaming velocities
increase the circular velocities from about 14 $\rm km/s$ to 16 $\rm km/s$.
They also delay the collapse of halos for a few million years, but do not have
any significant impact on the halo properties such as turbulent energy, radial
velocity, density and accretion rates. Sink particles of about $\rm \sim 10^5
M_{\odot}$ are formed at the end of our simulations and no clear distribution
of sink masses is observed in the presence of streaming motions. It is further
found that the impact of streaming velocities is less severe in massive halos
compared to the minihalos as reported in the previous studies.


title: An external-shock model for GRB afterglow 130427A

abstract:
  The complex multiwavelength emission of GRB afterglow 130427A (monitored in
the radio up to 10 days, in the optical and X-ray until 50 days, and at GeV
energies until 1 day) can be accounted for by a hybrid reverse-forward shock
synchrotron model, with inverse-Compton emerging only above a few GeV. The high
ratio of the early optical to late radio flux requires that the ambient medium
is a wind and that the forward-shock synchrotron spectrum peaks in the optical
at about 10 ks. The latter has two consequences: the wind must be very tenuous
and the optical emission before 10 ks must arise from the reverse-shock, as
suggested also by the bright optical flash that Raptor has monitored during the
prompt emission phase (<100 s). The VLA radio emission is from the
reverse-shock, the Swift X-ray emission is mostly from the forward-shock, but
the both shocks give comparable contributions to the Fermi GeV emission. The
weak wind implies a large blast-wave radius (8 t_{day}^{1/2} pc), which
requires a very tenuous circumstellar medium, suggesting that the massive
stellar progenitor of GRB 130427A resided in a super-bubble.


title: Obstructions to regularity in the classical Monge problem

abstract:
  We provide counterexamples to regularity of optimal maps in the classical
Monge problem under various assumptions on the initial data. Our construction
is based on a variant of the counterexample in \cite{LSW} to Lipschitz
regularity of the monotone optimal map between smooth densities supported on
convex domains.


title: Neutrino Mass Textures and Partial $\mu$-$\tau$ Symmetry

abstract:
  We discuss the viability of the $\mu$--$\tau$ interchange symmetry imposed on
the neutrino mass matrix in the flavor space. Whereas the exact symmetry is
shown to lead to textures of completely degenerate spectrum which is
incompatible with the neutrino oscillation data, introducing small
perturbations into the preceding textures, inserted in a minimal way, lead
however to four deformed textures representing an approximate $\mu$--$\tau$
symmetry. We motivate the form of these `minimal' textures, which disentangle
the effects of the perturbations, and present some concrete realizations
assuming exact $\mu$--$\tau$ at the Lagrangian level but at the expense of
adding new symmetries and matter fields.
  We find that all these deformed textures are capable to accommodate the
experimental data, and in all types of neutrino mass hierarchies, in particular
the non-vanishing value for the smallest mixing angle.


title:
Nucleation barriers at corners for cubic-to-tetragonal phase
  transformation

abstract:
  We are interested in the energetic cost of a martensitic inclusion of volume
$V$ in austenite for the cubic-to-tetragonal phase transformation. In contrast
with the work of [Kn\"upfer, Kohn, Otto: Comm. Pure Appl. Math. 66 (2013), no.
6, 867--904], we consider domain with a corner and obtain a better scaling law
for the minimal energy ($E_{min} \sim \min(V^{2/3},V^{7/9})$). Our predictions
are in a good agreement with physical experiments where nucleation of
martensite is usually observed near the corners of the specimen.

categories: math.AP math-ph math.MP physics.class-ph


title:
Finding sparse solutions of systems of polynomial equations via
  group-sparsity optimization

abstract:
  The paper deals with the problem of finding sparse solutions to systems of
polynomial equations possibly perturbed by noise. In particular, we show how
these solutions can be recovered from group-sparse solutions of a derived
system of linear equations. Then, two approaches are considered to find these
group-sparse solutions. The first one is based on a convex relaxation resulting
in a second-order cone programming formulation which can benefit from efficient
reweighting techniques for sparsity enhancement. For this approach, sufficient
conditions for the exact recovery of the sparsest solution to the polynomial
system are derived in the noiseless setting, while stable recovery results are
obtained for the noisy case. Though lacking a similar analysis, the second
approach provides a more computationally efficient algorithm based on a greedy
strategy adding the groups one-by-one. With respect to previous work, the
proposed methods recover the sparsest solution in a very short computing time
while remaining at least as accurate in terms of the probability of success.
This probability is empirically analyzed to emphasize the relationship between
the ability of the methods to solve the polynomial system and the sparsity of
the solution.


title: Isomorphism classes of $k$-involutions of algebraic groups of type $F_4$

abstract:
  We continue the classification of isomorphism classes of k-involutions of
exceptional algebraic groups. In this paper we classify k-involutions for split
groups of type F4 over certain fields, and their fixed point groups.The
classification of k-involutions is equivalent to the classification of
symmetric k-varieties.


title:
Weak convergence of the empirical process of intermittent maps in L2
  under long-range dependence

abstract:
  We study the behavior of the empirical distribution function of iterates of
intermittent maps in the Hilbert space of square inegrable functions with
respect to Lebesgue measure. In the long-range dependent case, we prove that
the empirical distribution function, suitably normalized, converges to a
degenerate stable process, and we give the corresponding almost sure result. We
apply the results to the convergence of the Wasserstein distance between the
empirical measure and the invariant measure. We also apply it to obtain the
asymptotic distribution of the corresponding Cram\'er-von-Mises statistic.


title: Exploiting tumor shrinkage through temporal optimization of radiotherapy

abstract:
  In multi-stage radiotherapy, a patient is treated in several stages separated
by weeks or months. This regimen has been motivated mostly by radiobiological
considerations, but also provides an approach to reduce normal tissue dose by
exploiting tumor shrinkage. The paper considers the optimal design of
multi-stage treatments, motivated by the clinical management of large liver
tumors for which normal liver dose constraints prohibit the administration of
an ablative radiation dose in a single treatment.
  We introduce a dynamic tumor model that incorporates three factors: radiation
induced cell kill, tumor shrinkage, and tumor cell repopulation. The design of
multi-stage radiotherapy is formulated as a mathematical optimization problem
in which the total dose to the liver is minimized, subject to delivering the
prescribed dose to the tumor. Based on the model, we gain insight into the
optimal administration of radiation over time, i.e. the optimal treatment gaps
and dose levels.
  We analyze treatments consisting of two stages in detail. The analysis
confirms the intuition that the second stage should be delivered just before
the tumor size reaches a minimum and repopulation overcompensates shrinking.
Furthermore, it was found that, for a large range of model parameters,
approximately one third of the dose should be delivered in the first stage. The
projected benefit of multi-stage treatments depends on model assumptions.
However, the model predicts large liver dose reductions by more than a factor
of two for plausible model parameters.
  The analysis of the tumor model suggests that substantial reduction in normal
tissue dose can be achieved by exploiting tumor shrinkage via an optimal design
of multi-stage treatments. This suggests taking a fresh look at multi-stage
radiotherapy for selected disease sites where substantial tumor regression
translates into reduced target volumes.


title:
Injection locking of a semiconductor laser to a multi-frequency
  reference beam

abstract:
  Injection locking is a well known and commonly used method for coherent light
amplification. Usually injection locking is done with a single-frequency
seeding beam. In this work we show that injection locking may also be achieved
in the case of multi-frequency seeding beam when slave laser provides
sufficient frequency filtering. One relevant parameter turns out to be the
frequency detuning between the free running slave laser and each injected
frequency component. Stable selective locking to a set of three components
separated of $1.2\,$GHz is obtained for (positive) detuning values between zero
and $1.5\,$GHz depending on seeding power (ranging from 10 to 150 microwatt).
This result suggests that, using distinct slave lasers for each line, a set of
mutually coherent narrow-linewidth high-power radiation modes can be obtained.


title: Absorption control in pseudodisordered photonic-crystal thin film

abstract:
  The positive effects of various perturbations introduced in a bidimensional
photonic-crystal patterned membrane on its integrated absorption are
investigated numerically and theoretically. Two phenomena responsible for the
enhanced absorption observed are identified: an increase of the spectral
density of modes, obtained thanks to folding mechanisms in the reciprocal
lattice, and a better coupling of the modes with the incident light. By
introducing a proper pseudodisordered pattern, we show that those two effects
can be exploited so as to overcome the integrated absorption obtained for an
optimized and single pattern unit cell photonic crystal.


title:
L-H transition dynamics in fluid turbulence simulations with
  neoclassical force balance

abstract:
  Spontaneous transport barrier generation at the edge of a magnetically
confined plasma is investigated. To this end, a model of electrostatic
turbulence in three-dimensional geometry is extended to account for the impact
of friction between trapped and passing particles on the radial electric field.
Non-linear flux-driven simulations are carried out, and it is shown that
considering the radial and temporal variations of the neoclassical friction
coefficients allows for a transport barrier to be generated above a threshold
of the input power.


title:
Structure of transition classes for factor codes on shifts of finite
  type

abstract:
  Given a factor code $\pi$ from a shift of finite type $X$ onto a sofic shift
$Y$, the class degree of $\pi$ is defined to be the minimal number of
transition classes over points of $Y$. In this paper we investigate structure
of transition classes and present several dynamical properties analogous to the
properties of fibers of finite-to-one codes. As a corollary, we show that for
an irreducible factor triple there cannot be a transition between two different
transition classes over a right transitive point, answering a question raised
by Quas.


title: Angular Momentum Generation by Parity Violation

abstract:
  We generalize our holographic derivation of spontaneous angular momentum
generation in 2 + 1 dimensions in several directions. We consider cases when a
parity violating perturbation responsible for the angular momentum generation
can be non-marginal (while in our previous paper we restricted to a marginal
perturbation), including all possible two-derivative interactions, with parity
violations triggered both by gauge and gravitational Chern-Simons terms in the
bulk. We make only a minimal assumption about the bulk geometry that it is
asymptotically AdS, respects the Poincar\'e symmetry in 2 + 1 dimensions, and
has a horizon. In this generic setup, we find a remarkably concise and
universal formula for the expectation value of the angular momentum density, to
all orders in the parity violating perturbation.


title: Ways of Listening and Modes of Being: Electroacoustic Auditory Display

abstract:
  Auditory display is concerned with the use of non-speech sound to communicate
information. If the term seems at first oxymoronic, then consider auditory
display as an activity of perceptualization, that is, the process of making
perceptible to humans aspects or features of a given data set or system. Most
commonly this is done using visual representations (which process we call
visualization) but it is not limited to the visual channel and recent years
have witnessed the increased use of auditory representations in the production
of tools for exploring data. By way of semiotics and an aesthetic perspective
shift this article posits that auditory display may be considered a form of
organized sound and explores the listening experience in this context.


title: Corner Detection and Arc Approximation of Planar Data Set

abstract:
  The aim of this paper is to present a new method of approximation of planar
data set using only arcs or segments. The first problem we are trying to solve
is the following: the CNC machines can work only with simple curves (arcs or
segments, indeed). So, if we have a contour of an object and we want to cut,
for example, glass or metal following that profile, we need a continuous curve
composed by linear or circular paths only. Moreover, we want to minimize the
number of these paths. The second problem is the following: the contour of an
object is detected by a specific laser, which collects a discrete data set. The
laser detects a good approximation of a point if this point is not a corner of
the object. So in many cases our data set will not contain the real corners.
Our task is to present a method on how to find these particular points. A third
purpose is to study the regularity of the approximating curve, which can be
$G^1$ or $C^0$ continuous. The entire method is developed using single arcs,
segments and in certain cases biarcs, in order to ensure the smoothness of the
final path.


title:
Spatially Adaptive Stochastic Methods for Fluid-Structure Interactions
  Subject to Thermal Fluctuations in Domains with Complex Geometries

abstract:
  We develop stochastic mixed finite element methods for spatially adaptive
simulations of fluid-structure interactions when subject to thermal
fluctuations. To account for thermal fluctuations, we introduce a discrete
fluctuation-dissipation balance condition to develop compatible stochastic
driving fields for our discretization. We perform analysis that shows our
condition is sufficient to ensure results consistent with statistical
mechanics. We show the Gibbs-Boltzmann distribution is invariant under the
stochastic dynamics of the semi-discretization. To generate efficiently the
required stochastic driving fields, we develop a Gibbs sampler based on
iterative methods and multigrid to generate fields with $O(N)$ computational
complexity. Our stochastic methods provide an alternative to uniform
discretizations on periodic domains that rely on Fast Fourier Transforms. To
demonstrate in practice our stochastic computational methods, we investigate
within channel geometries having internal obstacles and no-slip walls how the
mobility/diffusivity of particles depends on location. Our methods extend the
applicability of fluctuating hydrodynamic approaches by allowing for spatially
adaptive resolution of the mechanics and for domains that have complex
geometries relevant in many applications.


title:
Subcritical $\mathcal{U}$-bootstrap percolation models have non-trivial
  phase transitions

abstract:
  We prove that there exist natural generalizations of the classical bootstrap
percolation model on $\mathbb{Z}^2$ that have non-trivial critical
probabilities, and moreover we characterize all homogeneous, local, monotone
models with this property.
  Van Enter (in the case $d=r=2$) and Schonmann (for all $d \geq r \geq 2$)
proved that $r$-neighbour bootstrap percolation models have trivial critical
probabilities on $\mathbb{Z}^d$ for every choice of the parameters $d \geq r
\geq 2$: that is, an initial set of density $p$ almost surely percolates
$\mathbb{Z}^d$ for every $p>0$. These results effectively ended the study of
bootstrap percolation on infinite lattices.
  Recently Bollob\'as, Smith and Uzzell introduced a broad class of percolation
models called $\mathcal{U}$-bootstrap percolation, which includes $r$-neighbour
bootstrap percolation as a special case. They divided two-dimensional
$\mathcal{U}$-bootstrap percolation models into three classes -- subcritical,
critical and supercritical -- and they proved that, like classical 2-neighbour
bootstrap percolation, critical and supercritical $\mathcal{U}$-bootstrap
percolation models have trivial critical probabilities on $\mathbb{Z}^2$. They
left open the question as to what happens in the case of subcritical families.
In this paper we answer that question: we show that every subcritical
$\mathcal{U}$-bootstrap percolation model has a non-trivial critical
probability on $\mathbb{Z}^2$. This is new except for a certain `degenerate'
subclass of symmetric models that can be coupled from below with oriented site
percolation. Our results re-open the study of critical probabilities in
bootstrap percolation on infinite lattices, and they allow one to ask many
questions of subcritical bootstrap percolation models that are typically asked
of site or bond percolation.


title:
Reconstruction of new holographic scalar field models of dark energy in
  Brans-Dicke Universe

abstract:
  Motivated by the work [K. Karami, J. Fehri, {{\it Phys. Lett. B}} {\bf 684},
61 (2010)] and [A. Sheykhi, {{\it Phys. Lett. B}} {\bf 681}, 205 (2009)], we
generalize their work to the new holographic dark energy model with
$\rho_D=\frac{3\phi^2}{4\omega}(\mu H^2+\nu\dot{H})$ in the framework of
Brans-Dicke cosmology. Concretely, we study the correspondence between the
quintessence, tachyon, K-essence, dilaton scalar field and Chaplygin gas model
with the new holographic dark energy model in the non-flat Brans-Dicke
universe. Furthermore, we reconstruct the potentials and dynamics for these
models. By analysis we can show that for new holographic quintessence and
Chaplygin gas models, if the related parameters to the potentials satisfy some
constraints, the accelerated expansion can be achieved in Brans-Dicke
cosmology. Especially the counterparts of fields and potentials in general
relativity can describe accelerated expansion of the universe. It is worth
stressing that not only can we give some new results in the framework of
Brans-Dicke cosmology, but also the previous results of the new holographic
dark energy in Einstein gravity can be included as special cases given by us.


title: Bianchi-V string cosmology with power law expansion in $f(R, T)$ Gravity

abstract:
  In this paper, we search the existence of Bianchi-V string cosmological model
in $f(R,T)$ gravity with power law expansion. Einstein's field equations have
been solved by taking into account the law of variation of Hubble's parameter
that yields the constant value of deceleration parameter (DP). We observe that
the massive strings dominate the early universe but they do not survive for
long time and finally disappear from the universe. We examine the nature of
classical potential and also discuss the physical properties of universe.


title: Shining LUX on Isospin-Violating Dark Matter Beyond Leading Order

abstract:
  Isospin-violating dark matter (IVDM) has been proposed as a viable scenario
to reconcile conflicting positive and null results from direct detection dark
matter experiments. We show that the lowest-order dark matter-nucleus
scattering rate can receive large and nucleus-dependent corrections at
next-to-leading order (NLO) in the chiral expansion. The size of these
corrections depends on the specific couplings of dark matter to quark flavors
and gluons. In general the full NLO dark-matter-nucleus cross-section is not
adequately described by just the zero-energy proton and neutron couplings.
These statements are concretely illustrated in a scenario where the dark matter
couples to quarks through scalar operators. We find the canonical IVDM scenario
can reconcile the null XENON and LUX results and the recent CDMS-Si findings
provided its couplings to second and third generation quarks either lie on a
special line or are suppressed. Equally good fits with new values of the
neutron-to-proton coupling ratio are found in the presence of nonzero heavy
quark couplings. CDMS-Si remains in tension with LUX and XENON10/100 but is not
excluded.


title: Parton Distributions and Event Generators

abstract:
  We present the implementation within the Pythia8 event generator of a set of
parton distributions based on NNPDF methodology. We construct a set of
leading-order parton distributions with QED corrections, NNPDF2.3QED LO set,
based on the same data as the previous NNPDF2.3 NLO and NNLO PDF sets. We
compare this PDF set to its higher-order counterparts, we discuss its
implementation as an internal set in Pythia8, and we use it to study some of
the phenomenological implications of photon-initiated contributions for
dilepton production at hadron colliders.


title:
The large-scale structure of the halo of the Andromeda Galaxy Part I:
  global stellar density, morphology and metallicity properties

abstract:
  We present an analysis of the large-scale structure of the halo of the
Andromeda galaxy, based on the Pan-Andromeda Archeological Survey (PAndAS),
currently the most complete map of resolved stellar populations in any galactic
halo. Despite copious substructure, the global halo populations follow closely
power law profiles that become steeper with increasing metallicity. We divide
the sample into stream-like populations and a smooth halo component. Fitting a
three-dimensional halo model reveals that the most metal-poor populations
([Fe/H]<-1.7) are distributed approximately spherically (slightly prolate with
ellipticity c/a=1.09+/-0.03), with only a relatively small fraction (42%)
residing in discernible stream-like structures. The sphericity of the ancient
smooth component strongly hints that the dark matter halo is also approximately
spherical. More metal-rich populations contain higher fractions of stars in
streams (86% for [Fe/H]>-0.6). The space density of the smooth metal-poor
component has a global power-law slope of -3.08+/-0.07, and a non-parametric
fit shows that the slope remains nearly constant from 30kpc to 300kpc. The
total stellar mass in the halo at distances beyond 2 degrees is 1.1x10^10 Solar
masses, while that of the smooth component is 3x10^9 Solar masses.
Extrapolating into the inner galaxy, the total stellar mass of the smooth halo
is plausibly 8x10^9 Solar masses. We detect a substantial metallicity gradient,
which declines from [Fe/H]=-0.7 at R=30kpc to [Fe/H]=-1.5 at R=150kpc for the
full sample, with the smooth halo being 0.2dex more metal poor than the full
sample at each radius. While qualitatively in-line with expectations from
cosmological simulations, these observations are of great importance as they
provide a prototype template that such simulations must now be able to
reproduce in quantitative detail.


title: From Satisfying to Violating the Null Energy Condition

abstract:
  We construct a theory which admits a time-dependent solution smoothly
interpolating between a null energy condition (NEC)-satisfying phase at early
times and a NEC-violating phase at late times. We first review earlier attempts
to violate the NEC and an argument of Rubakov, presented in 1305.2614, which
forbids the existence of such interpolating solutions in a single-field
dilation-invariant theory. We then construct a theory which, in addition to
possessing a Poincar\'e-invariant vacuum, does admit such a solution. For a
wide range of parameters, perturbations around this solution are at all times
stable, comfortably subluminal and weakly-coupled. The theory requires us to
explicitly break dilation-invariance, so it is unlikely that the theory is
fully stable under quantum corrections, but we argue that the existence of a
healthy interpolating solution is quantum-mechanically robust.


title:
Experimental realization of post-selected weak measurements on an NMR
  quantum processor

abstract:
  The ability to post-select the outcomes of an experiment is a useful
theoretical concept and experimental tool. In the context of weak measurements
post-selection can lead to surprising results such as complex weak values
outside the range of eigenvalues. Usually post-selection is realized by a
projective measurement, which is hard to implement in ensemble systems such as
NMR. We demonstrate the first experiment of a weak measurement with
post-selection on an NMR quantum information processor. Our setup is used for
measuring complex weak values and weak values outside the range of eigenvalues.
The scheme for overcoming the problem of post-selection in an ensemble quantum
computer is general and can be applied to any circuit-based implementation.
This experiment paves the way for studying and exploiting post-selection and
weak measurements in systems where projective measurements are hard to realize
experimentally.


title: Improving Higgs plus Jets analyses through Fox--Wolfram Moments

abstract:
  It is well known that understanding the structure of jet radiation can
significantly improve Higgs analyses. Using Fox--Wolfram moments we
systematically study the geometric patterns of additional jets in weak boson
fusion Higgs production with a decay to photons. First, we find a significant
improvement with respect to the standard analysis based on an analysis of the
tagging jet correlations. In addition, we show that replacing a jet veto by a
Fox-Wolfram moment analysis of the extra jet radiation almost doubles the
signal-to-background ratio. Finally, we show that this improvement can also be
achieved based on a modified definition of the Fox--Wolfram moments which
avoids introducing a new physical scale below the factorization scale. This
modification can reduce the impact of theory uncertainties on the Higgs rate
and couplings measurements.


title:
Can deeply underdoped superconducting cuprates be topological
  superconductors?

abstract:
  The nodal $d_{x^2-y^2}$ superconducting gap is a hallmark of the cuprate high
T$_c$ superconductors. Surprisingly recent angle-resolved photoemission
spectroscopy of deeply underdoped cuprates revealed a nodeless energy gap which
is adhered to the Fermi surface. Importantly this phenomenon is observed for
compounds across several different cuprate families. In this letter we propose
an exciting possibility, namely the fully gapped state is a topological
superconductor.


title: Herschel-ATLAS: Modelling the first strong gravitational lenses

abstract:
  We have determined the mass-density radial profiles of the first five strong
gravitational lens systems discovered by the Herschel Astrophysical Terahertz
Large Area Survey (H-ATLAS). We present an enhancement of the semi-linear lens
inversion method of Warren & Dye which allows simultaneous reconstruction of
several different wavebands and apply this to dual-band imaging of the lenses
acquired with the Hubble Space Telescope. The five systems analysed here have
lens redshifts which span a range, 0.22<z<0.94. Our findings are consistent
with other studies by concluding that: 1) the logarithmic slope of the total
mass density profile steepens with decreasing redshift; 2) the slope is
positively correlated with the average total projected mass density of the lens
contained within half the effective radius and negatively correlated with the
effective radius; 3) the fraction of dark matter contained within half the
effective radius increases with increasing effective radius and increases with
redshift.


title:
Large Variety of New Pulsating Stars in the OGLE-III Galactic Disk
  Fields

abstract:
  We present the results of a search for pulsating stars in the 7.12 deg^2
OGLE-III Galactic disk area in the direction tangent to the Centaurus Arm. We
report the identification of 20 Classical Cepheids, 45 RR Lyr type stars, 31
Long-Period Variables, such as Miras and Semi-Regular Variables, one pulsating
white dwarf, and 58 very likely delta Sct type stars. Based on asteroseismic
models constructed for one quadruple-mode and six triple-mode delta Sct type
pulsators, we estimated masses, metallicities, ages, and distance moduli to
these objects. The modeled stars have masses in the range 0.9-2.5 M_sun and are
located at distances between 2.5 kpc and 6.2 kpc. Two triple-mode and one
double-mode pulsators seem to be Population II stars of the SX Phe type,
probably from the Galactic halo. Our sample also includes candidates for Type
II Cepheids and unclassified short-period (P<0.23 d) multi-mode stars which
could be either delta Sct or beta Cep type stars. One of the detected variables
is a very likely delta Sct star with an exceptionally high peak-to-peak I-band
amplitude of 0.35 mag at the very short period of 0.0196 d. All reported
pulsating variables but one object are new discoveries. They are included in
the OGLE-III Catalog of Variable Stars. Finally, we introduce the on-going
OGLE-IV Galactic Disk Survey, which covers more than half of the Galactic
plane. For the purposes of future works on the spiral structure and star
formation history of the Milky Way, we have already compiled a list of known
Galactic Classical Cepheids.


title:
An improved measurement of baryon acoustic oscillations from the
  correlation function of galaxy clusters at $z \sim 0.3$

abstract:
  We detect the peak of baryon acoustic oscillations (BAO) in the two-point
correlation function of a spectroscopic sample of $25226$ clusters selected
from the Sloan Digital Sky Survey. Galaxy clusters, as tracers of massive dark
matter haloes, are highly biased structures. The linear bias $b$ of the sample
considered in this work, that we estimate from the projected correlation
function, is $b \sigma_8 = 1.72 \pm 0.03$. Thanks to the high signal in the
cluster correlation function and to the accurate spectroscopic redshift
measurements, we can clearly detect the BAO peak and determine its position,
$s_p$, with high accuracy, despite the relative paucity of the sample. Our
measurement, $s_p = 104 \pm 7 \, \mathrm{Mpc} \, h^{-1}$, is in good agreement
with previous estimates from large galaxy surveys, and has a similar
uncertainty. The BAO measurement presented in this work thus provides a new
strong confirmation of the concordance cosmological model and demonstrates the
power and promise of galaxy clusters as key probes for cosmological
applications based on large scale structures.


title: Simplified Models of Mixed Dark Matter

abstract:
  We explore simplified models of mixed dark matter (DM), defined here to be a
stable relic composed of a singlet and an electroweak charged state. Our setup
describes a broad spectrum of thermal DM candidates that can naturally
accommodate the observed DM abundance but are subject to substantial
constraints from current and upcoming direct detection experiments. We identify
"blind spots" at which the DM-Higgs coupling is identically zero, thus
nullifying direct detection constraints on spin independent scattering.
Furthermore, we characterize the fine-tuning in mixing angles, i.e.
well-tempering, required for thermal freeze-out to accommodate the observed
abundance. Present and projected limits from LUX and XENON1T force many thermal
relic models into blind spot tuning, well-tempering, or both. This simplified
model framework generalizes bino-Higgsino DM in the MSSM, singlino-Higgsino DM
in the NMSSM, and scalar DM candidates that appear in models of extended Higgs
sectors.


title:
New fission fragment distributions and r-process origin of the
  rare-earth elements

abstract:
  Neutron star (NS) merger ejecta offer a viable site for the production of
heavy r-process elements with nuclear mass numbers A > 140. The crucial role of
fission recycling is responsible for the robustness of this site against many
astrophysical uncertainties, but calculations sensitively depend on nuclear
physics. In particular the fission fragment yields determine the creation of
110 < A < 170 nuclei. Here we apply a new scission-point model, called SPY, to
derive the fission fragment distribution (FFD) of all relevant neutron-rich,
fissioning nuclei. The model predicts a doubly asymmetric FFD in the abundant A
~ 278 mass region that is responsible for the final recycling of the fissioning
material. Using ejecta conditions based on relativistic NS merger calculations
we show that this specific FFD leads to a production of the A ~ 165 rare-earth
peak that is nicely compatible with the abundance patterns in the Sun and
metal-poor stars. This new finding further strengthens the case of NS mergers
as possible dominant origin of r-nuclei with A > 140.


title:
Herschel-ATLAS: deep HST/WFC3 imaging of strongly lensed submillimeter
  galaxies

abstract:
  We report on deep near-infrared observations obtained with the Wide Field
Camera 3 (WFC3) onboard the Hubble Space Telescope (HST) of the first five
confirmed gravitational lensing events discovered by the Herschel Astrophysical
Terahertz Large Area Survey (H-ATLAS). We succeed in disentangling the
background galaxy from the lens to gain separate photometry of the two
components. The HST data allow us to significantly improve on previous
constraints of the mass in stars of the lensed galaxy and to perform accurate
lens modelling of these systems, as described in the accompanying paper by Dye
et al. We fit the spectral energy distributions of the background sources from
near-IR to millimetre wavelengths and use the magnification factors estimated
by Dye et al. to derive the intrinsic properties of the lensed galaxies. We
find these galaxies to have star-formation rates of approximately 400 to 2000
M_sol/yr, with approximately (6-25)x10^10 M_sol of their baryonic mass already
turned into stars. At these rates of star formation, all remaining molecular
gas will be exhausted in less than 100 Myr, reaching a final mass in stars of a
few 10^11 M_sol. These galaxies are thus proto-ellipticals caught during their
major episode of star formation, and observed at the peak epoch z=1.5-3 of the
cosmic star formation history of the Universe.


title:
Binding and interlayer force in the near-contact region of two graphite
  slabs: experiment and theory

abstract:
  Via a novel experiment, Liu \emph{et al.} [Phys. Rev. B, {\bf 85}, 205418
(2012)] estimated the graphite binding energy, specifically the cleavage
energy, an important physical property of bulk graphite. We re-examine the data
analysis and note that within the standard Lennard-Jones model employed, there
are difficulties in achieving internal consistency in the reproduction of the
graphite elastic properties. By employing similar models which guarantee
consistency with the elastic constant, we find a wide range of model dependent
binding energy values from the same experimental data. We attribute some of the
difficulty in the determination of the binding energy to: i) limited
theoretical understanding of the van der Waals dispersion of graphite cleavage,
ii) the mis-match between the strong bending stiffness of the graphite-SiO$_2$
cantilever and the weak asymptotic inter-layer forces that are integrated over
to produce the binding energy. We find, however, that the data does support
determination of a maximum inter-layer force that is relatively model
independent. We conclude that the peak force per unit area is $1.1 \pm 0.15$GPa
for cleavage, and occurs at an inter-layer spacing of $0.377\pm 0.013$nm.


title:
Numerical simulations of super-critical black hole accretion flows in
  general relativity

abstract:
  A new general relativistic radiation magnetohydrodynamical code KORAL, is
described, which employs the M1 scheme to close the radiation moment equations.
The code has been successfully verified against a number of tests. Axisymmetric
simulations of super-critical magnetized accretion on a non-rotating black hole
(a=0.0) and a spinning black hole (a=0.9) are presented. The accretion rates in
the two models are \dot M = 100-200 \dot M_Edd. These first general
relativistic simulations of super-critical black hole accretion are potentially
relevant to tidal disruption events and hyper-accreting supermassive black
holes in the early universe. Both simulated models are optically and
geometrically thick, and have funnels through which energy escapes in the form
of relativistic gas, Poynting flux and radiative flux. The jet is significantly
more powerful in the a=0.9 run. The net energy outflow rate in the two runs
correspond to efficiencies of 5% (a=0) and 33% (a=0.9), as measured with
respect to the mass accretion rate at the black hole. These efficiencies agree
well with those measured in previous simulations of non-radiative geometrically
thick disks. Furthermore, in the a=0.9 run, the outflow power appears to
originate in the spinning black hole, suggesting that the associated physics is
again similar in non-radiative and super-critical accretion flows. While the
two simulations are efficient in terms of total energy outflow, both runs are
radiatively inefficient. Their luminosities are only \sim 1-10 L_Edd, which
corresponds to a radiative efficiency \sim 0.1%. Interestingly, most of the
radiative luminosity emerges through the funnels, which subtend a very small
solid angle. Therefore, measured in terms of a local radiative flux, the
emitted radiation is highly super-Eddington.


title: M-theory Compactifications to Three Dimensions with M2-brane Potentials

abstract:
  We study a class of compactifications of M-theory to three dimensions that
preserve N=2 supersymmetry and which have the defining feature that a probe
space-time filling M2 brane feels a non-trivial potential on the internal
manifold. Using M-theory/F-theory duality such compactifications include the
uplifts of 4-dimensional N=1 type IIB compactifications with D3 potentials to
strong coupling. We study the most general 8-dimensional manifolds supporting
these properties, derive the most general flux that induces an M2 potential,
and show that it is parameterised in terms of two real vectors. We study the
supersymmetry equations when only this flux is present and show that over the
locus where the M2 potential is non-vanishing the background takes the form of
a Calabi-Yau three-fold fibered over a 2-dimensional base spanned by the flux
vectors, while at the minima of the potential the flux vanishes. Allowing also
for non-vanishing four-form flux with one leg in the internal directions we
find that the Calabi-Yau three-fold in the fibration is replaced by an
SU(3)-structure manifold with torsion classes satisfying 2 W_4=-W_5.


title:
Radiotherapy planning for glioblastoma based on a tumor growth model:
  Improving target volume delineation

abstract:
  Glioblastoma are known to infiltrate the brain parenchyma instead of forming
a solid tumor mass with a defined boundary. Only the part of the tumor with
high tumor cell density can be localized through imaging directly. In contrast,
brain tissue infiltrated by tumor cells at low density appears normal on
current imaging modalities. In clinical practice, a uniform margin is applied
to account for microscopic spread of disease.
  The current treatment planning procedure can potentially be improved by
accounting for the anisotropy of tumor growth: Anatomical barriers such as the
falx cerebri represent boundaries for migrating tumor cells. In addition, tumor
cells primarily spread in white matter and infiltrate gray matter at lower
rate. We investigate the use of a phenomenological tumor growth model for
treatment planning. The model is based on the Fisher-Kolmogorov equation, which
formalizes these growth characteristics and estimates the spatial distribution
of tumor cells in normal appearing regions of the brain. The target volume for
radiotherapy planning can be defined as an isoline of the simulated tumor cell
density.
  A retrospective study involving 10 glioblastoma patients has been performed.
To illustrate the main findings of the study, a detailed case study is
presented for a glioblastoma located close to the falx. In this situation, the
falx represents a boundary for migrating tumor cells, whereas the corpus
callosum provides a route for the tumor to spread to the contralateral
hemisphere. We further discuss the sensitivity of the model with respect to the
input parameters. Correct segmentation of the brain appears to be the most
crucial model input.
  We conclude that the tumor growth model provides a method to account for
anisotropic growth patterns of glioblastoma, and may therefore provide a tool
to make target delineation more objective and automated.


title: Effect of slip on circulation inside a droplet

abstract:
  Internal recirculation in a moving droplet plays an important role in several
droplet-based microfluidic devices as it enhances mixing, chemical reaction and
heat transfer. The occurrence of fluid slip at the wall, which becomes
prominent at high shear rates and lower length scales, results in a significant
change in droplet circulation. Using molecular dynamics (MD) simulations, the
presence of circulation in droplets is demonstrated and quantified. Circulation
is shown to vary inversely with slip length, which is a measure of interface
wettability. A simple circulation model is established that captures the effect
of slip on droplet circulation. Scaling parameters for circulation and slip
length are identified from the circulation model which leads to the collapse of
data for droplets with varying aspect ratio (AR) and slip length. The model is
validated using continuum and MD simulations and is shown to be accurate for
droplets with high AR.


title:
The IceProd Framework: Distributed Data Processing for the IceCube
  Neutrino Observatory

abstract:
  IceCube is a one-gigaton instrument located at the geographic South Pole,
designed to detect cosmic neutrinos, iden- tify the particle nature of dark
matter, and study high-energy neutrinos themselves. Simulation of the IceCube
detector and processing of data require a significant amount of computational
resources. IceProd is a distributed management system based on Python, XML-RPC
and GridFTP. It is driven by a central database in order to coordinate and
admin- ister production of simulations and processing of data produced by the
IceCube detector. IceProd runs as a separate layer on top of other middleware
and can take advantage of a variety of computing resources, including grids and
batch systems such as CREAM, Condor, and PBS. This is accomplished by a set of
dedicated daemons that process job submission in a coordinated fashion through
the use of middleware plugins that serve to abstract the details of job
submission and job management from the framework.


title:
On a class of Calder\'on-Zygmund operators arising from projections of
  martingale transforms

abstract:
  We prove that a large class of operators, which arise as the projections of
martingale transforms of stochastic integrals with respect to Brownian motion,
as well as other closely related operators, are in fact Calder\'on--Zygmund
operators. Consequently, such operators are not only bounded on $L^p$,
$1<p<\infty$, but also satisfy weak-type inequalities. Unlike the boundedness
on $L^p,$ which can be obtained directly from the Burkholder martingale
transform inequalities, the weak-type estimates do not follow from the
corresponding martingale results.


title: Chemical abundance studies of CP stars in open clusters

abstract:
  In stellar astrophysics, the study of the atmospheres of early-type stars
plays a very special role. The atmospheres of these stars display a variety of
different phenomena, such as the presence of large magnetic fields, strong
surface convection, pulsation, diffusion of chemical elements. In particular,
about 10% of early F-, A- and late B-type stars present chemical peculiarities,
which rise as a result of diffusion. A detailed study of the evolution of the
chemical peculiarities as traces of diffusion processes requires the precise
knowledge of stellar ages and initial chemical composition. Open clusters
provide these information: 1) it is possible to assume that all cluster members
have approximately the same original chemical composition and age; 2) the age
of stars belonging to open clusters can be determined with much higher accuracy
than for field stars. For this reason chemically peculiar stars member of open
clusters have been targeted to study the evolution of the chemical
peculiarities primarily to provide constraints to diffusion models. We review
the abundance studies of chemically peculiar stars in open clusters performed
until now, putting their results into the broader context of stellar evolution.


title:
Mathematical Model of a pH-gradient Creation at Isoelectrofocusing. Part
  IV. Theory

abstract:
  The mathematical model describing the non-stationary natural pH-gradient
arising under the action of an electric field in an aqueous solution of
ampholytes (amino acids) is constructed. The model is a part of a more general
model of the isoelectrofocusing (IEF) process. The presented model takes into
account: 1) general Ohm's law (electric current flux includes the diffusive
electric current); 2) dissociation of water; 3) difference between isoelectric
point (IEP) and isoionic point (PZC -- point of zero charge). We also study the
Kohlraush's function evolution and discuss the role of the Poisson-Boltzmann
equation.


title: Why do mayflies change their gill kinematics as they grow?

abstract:
  The mayfly nymph breathes under water through an oscillating array of
wing-shaped tracheal gills. As the nymph grows, the kinematics of these gills
change abruptly from rowing to flapping. The classical fluid dynamics approach
to consider the mayfly nymph as a pumping device fails in giving clear reasons
to this switch. In order to understand the whys and the hows of this switch
between the two distinct kinematics, we analyze the problem under a Lagrangian
viewpoint. We consider that a good Lagrangian transport that distributes and
spreads water and dissolved oxygen well between and around the gills is the
main goal of the gill motion. Using this Lagrangian approach we are able to
provide the reason behind the switch from rowing to flapping that the mayfly
nymph experiences as it grows. More precisely, recent and powerful tools from
this Lagrangian approach are applied to in-sillico mayfly nymph experiments,
where body shape, as well as, gill shapes, structures and kinematics are
matched to those from in-vivo. In this letter, we show both qualitatively and
quantitatively how the change of kinematics enables a better attraction,
stirring and confinement of water charged of dissolved oxygen inside the gills
area. From the computational velocity field we reveal attracting barriers to
transport, i.e. attracting Lagrangian coherent structures, that form the
transport skeleton between and around the gills. In addition, we quantify how
well the fluid particles and consequently dissolved oxgen is spread and stirred
inside the gills area.


title: On quadratic irrationals with bounded partial quotients

abstract:
  It is shown that for some explicit constants $c>0, A>0$, the asymptotic for
the number of positive non-square discriminants $D<x$ with fundamental solution
$\varepsilon_D< x^{\frac 12+\alpha}, 0<\alpha <c$, remains preserved if we
require moreover $\mathbb Q(\sqrt D)$ to contain an irrational with partial
quotients bounded by $A$.


title: Feasibility of Lithium Storage on Graphene and Its Derivatives

abstract:
  Nanomaterials are anticipated to be promising storage media, owing to their
high surface-to-mass ratio. The high hydrogen capacity achieved by using
graphene has reinforced this opinion and motivated investigations of the
possibility to use it to store another important energy carrier - lithium (Li).
While the first-principles computations show that the Li capacity of pristine
graphene, limited by Li clustering and phase separation, is lower than that
offered by Li intercalation in graphite, we explore the feasibility of
modifying graphene for better Li storage. It is found that certain structural
defects in graphene can bind Li stably, yet more efficacious approach is
through substitution doping with boron (B). In particular, the layered C3B
compound stands out as a promising Li storage medium. The monolayer C3B has a
capacity of 714 mAh/g (as Li1.25C3B), and the capacity of stacked C3B is 857
mAh/g (as Li1.5C3B), which is about twice as large as graphite's 372 mAh/g (as
LiC6). Our results help clarify the mechanism of Li storage in low-dimensional
materials, and shed light on the rational design of nano-architectures for
energy storage.


title: A remark on solutions of the Pell equation

abstract:
  The main purpose of this Note is to provide a non-trivial bound on certain
Kloosterman sums as considered in the recent paper of E. Fouvry [F], leading to
a small improvement of his result on the Pell equation.


title: The Dynamics of Ultracompact HII Regions

abstract:
  Many ultracompact HII regions exhibit a cometary morphology in radio
continuum emission. In such regions, a young massive star is probably ablating,
through its ultraviolet radiation, the molecular cloud clump that spawned it.
On one side of the star, the radiation drives an ionization front that stalls
in dense molecular gas. On the other side, ionized gas streams outward into the
more rarefied environment. This wind is underpressured with respect to the
neutral gas. The difference in pressure draws in more cloud material, feeding
the wind until the densest molecular gas is dissipated.
  Recent, time-dependent simulations of massive stars turning on within
molecular gas show the system evolving in a direction similar to that just
described. Here, we explore a semi-analytic model in which the wind is
axisymmetric and has already achieved a steady state. Adoption of this
simplified picture allows us to study the dependence of both the wind and its
bounding ionization front on the stellar luminosity, the peak molecular
density, and the displacement of the star from the center of the clump. For
typical parameter values, the wind accelerates transonically to a speed of
about 15 km / s, and transports mass outward at a rate of 10^-4 solar masses
per year. Stellar radiation pressure acts to steepen the density gradient of
the wind.


title: What does a rate in a mean ergodic theorem imply?

abstract:
  We develop a general framework for the inverse mean ergodic theorems with
rates for operator semigroups thus completing a construction of the theory
initiated in [16] and [17].


title:
A first-principles study of the electronic structure of Iron-Selenium;
  Implications for electron-phonon superconductivity

abstract:
  We have performed density functional theory (DFT) calculations using the
linearized augmented plane wave method (LAPW) with the local density
approximation (LDA) functional to study the electronic structure of the
iron-based superconductor Iron-Selenium (FeSe). In our study, we have performed
a comprehensive set of calculations involving structural, atomic, and spin
configurations. All calculations were executed using the tetragonal lead-oxide
or P4/nmm structure, with various volumes, c/a ratios and internal parameters.
Furthermore, we investigated the spin polarization using the LDA functional to
assess ferromagnetism in this material. The paramagnetic LDA calculations find
the equilibrium configuration of FeSe in the P4/nmm structure to have a volume
of 472.5au$^3$ with a c/a ratio of 1.50 and internal parameter of 0.255, with
the ferromagnetic having comparable results to the paramagnetic case. In
addition, we calculated total energies for FeSe using a pseudopotential method,
and found comparable results to the LAPW calculations. Superconductivity
calculations were done using the Gaspari-Gyorffy and the McMillan formalism and
found substantial electron-phonon coupling. Under pressure, our calculations
show that the superconductivity critical temperature continues to rise, but
underestimates the measured values.


title:
Resembling dark energy and modified gravity with Finsler-Randers
  cosmology

abstract:
  In this article we present the cosmological equivalence between the
relativistic Finsler-Randers cosmology, with dark energy and modified gravity
constructions, at the background level. Starting from a small deviation from
the quadraticity of the Riemannian geometry, through which the local structure
of General Relativity is modified and the curvature theory is extended, we
extract the modified Friedmann equation. The corresponding extended
Finsler-Randers cosmology is very interesting, and it can mimic dark-energy and
modified gravity, describing a large class of scale-factor evolutions, from
inflation to late-time acceleration, including the phantom regime. In this
respect, the non-trivial universe evolution is not attributed to a new scalar
field, or to gravitational modification, but it arises from the modification of
the geometry itself.


title:
On the Origin of the Hubble Sequence: I. Insights on Galaxy Color
  Migration from Cosmological Simulations

abstract:
  An analysis of more than 3000 galaxies resolved at better than 114 pc/h at
z=0.62 in a LAOZI cosmological adaptive mesh refinement hydrodynamic simulation
is performed and insights gained on star formation quenching and color
migration. The vast majority of red galaxies are found to be within three
virial radii of a larger galaxy, at the onset of quenching when the specific
star formation rate experiences the sharpest decline to fall below
~10^{-2}-10^{-1}/Gyr (depending on the redshift). We shall thus call this
mechanism "environment quenching", which encompasses satellite quenching. Two
physical processes are largely responsible: ram-pressure stripping first
disconnects the galaxy from the cold gas supply on large scales, followed by a
longer period of cold gas starvation taking place in high velocity dispersion
environment, during the early part of which the existing dense cold gas in the
central region (<10kpc) is consumed by in situ star formation. Quenching is
found to be more efficient, but not faster, on average, in denser environment.
Throughout this quenching period and the ensuing one in the red sequence
galaxies follow nearly vertical tracks in the color-stellar-mass diagram. In
contrast, individual galaxies of all masses grow most of their stellar masses
in the blue cloud, prior to the onset of quenching, and progressively more
massive blue galaxies with already relatively older mean stellar ages continue
to enter the red sequence. Consequently, correlations among observables of red
galaxies - such as the age-mass relation - are largely inherited from their
blue progenitors at the onset of quenching. While the color makeup of the
entire galaxy population strongly depends on environment, which is a direct
result of environment quenching, physical properties of blue galaxies as a
sub-population show little dependence on environment.


title:
Human Mobility and Predictability enriched by Social Phenomena
  Information

abstract:
  The massive amounts of geolocation data collected from mobile phone records
has sparked an ongoing effort to understand and predict the mobility patterns
of human beings. In this work, we study the extent to which social phenomena
are reflected in mobile phone data, focusing in particular in the cases of
urban commute and major sports events. We illustrate how these events are
reflected in the data, and show how information about the events can be used to
improve predictability in a simple model for a mobile phone user's location.


title: Empirical Dynamic Programming

abstract:
  We propose empirical dynamic programming algorithms for Markov decision
processes (MDPs). In these algorithms, the exact expectation in the Bellman
operator in classical value iteration is replaced by an empirical estimate to
get `empirical value iteration' (EVI). Policy evaluation and policy improvement
in classical policy iteration are also replaced by simulation to get `empirical
policy iteration' (EPI). Thus, these empirical dynamic programming algorithms
involve iteration of a random operator, the empirical Bellman operator. We
introduce notions of probabilistic fixed points for such random monotone
operators. We develop a stochastic dominance framework for convergence analysis
of such operators. We then use this to give sample complexity bounds for both
EVI and EPI. We then provide various variations and extensions to asynchronous
empirical dynamic programming, the minimax empirical dynamic program, and show
how this can also be used to solve the dynamic newsvendor problem. Preliminary
experimental results suggest a faster rate of convergence than stochastic
approximation algorithms.


title:
Tail Asymptotics of Supremum of Certain Gaussian Processes over
  Threshold Dependent Random Intervals

abstract:
  Let $\{X(t),t\ge0\}$ be a centered Gaussian process and let $\gamma$ be a
non-negative constant. In this paper we study the asymptotics of
$P\{\underset{t\in [0,\mathcal{T}/u^\gamma]}\sup X(t)>u\}$ as $u\to\infty$,
with $\mathcal{T}$ an independent of $X$ non-negative random variable. As an
application, we derive the asymptotics of finite-time ruin probability of
time-changed fractional Brownian motion risk processes.


title:
Multi-dimensional fractional wave equation and some properties of its
  fundamental solution

abstract:
  In this paper, a multi-dimensional fractional wave equation that describes
propagation of the damped waves is introduced and analyzed. In contrast to the
fractional diffusion-wave equation, the fractional wave equation contains
fractional derivatives of the same order $\alpha,\ 1\le \alpha \le 2$ both in
space and in time. This feature is a decisive factor for inheriting some
crucial characteristics of the wave equation like e.g. a constant phase
velocity of the damped waves that are described by the fractional wave
equation. Some new integral representations of the fundamental solution of the
multi-dimensional wave equation are presented. In the one- and
three-dimensional cases, the fundamental solution is obtained in explicit form
in terms of elementary functions. In the one-dimensional case, the fundamental
solution is shown to be a spatial probability density function evolving in
time. However, for the dimensions grater than one, the fundamental solution can
be negative and therefore does not allow a probabilistic interpretation
anymore. To illustrate analytical findings, results of numerical calculations
and numerous plots are presented.


title:
Delay-Constrained Video Transmission: Quality-driven Resource Allocation
  and Scheduling

abstract:
  Real-time video demands quality-of-service (QoS) guarantees such as delay
bounds for end-user satisfaction. Furthermore, the tolerable delay varies
depending on the use case such as live streaming or two-way video conferencing.
Due to the inherently stochastic nature of wireless fading channels,
deterministic delay bounds are difficult to guarantee. Instead, we propose
providing statistical delay guarantees using the concept of effective capacity.
We consider a multiuser setup whereby different users have (possibly different)
delay QoS constraints. We derive the resource allocation policy that maximizes
the sum video quality and applies to any quality metric with concave
rate-quality mapping. We show that the optimal operating point per user is such
that the rate-distortion slope is the inverse of the supported video source
rate per unit bandwidth, a key metric we refer to as the source spectral
efficiency. We also solve the alternative problem of fairness-based resource
allocation whereby the objective is to maximize the minimum video quality
across users. Finally, we derive user admission and scheduling policies that
enable selecting a maximal user subset such that all selected users can meet
their statistical delay requirement. Results show that video users with
differentiated QoS requirements can achieve similar video quality with vastly
different resource requirements. Thus, QoS-aware scheduling and resource
allocation enable supporting significantly more users under the same resource
constraints.


title: Radiation power and linewidth of a semifluxon-based Josephson oscillator

abstract:
  We demonstrate a high-frequency generator operating at ~200GHz based on
flipping a semifluxon in a Josephson junction of moderate normalized length.
The semifluxon spontaneously appears at the $\pi$ discontinuity of the
Josephson phase artificially created by means of two tiny current injectors.
The radiation is detected by an on-chip detector (tunnel junction). The
estimated radiation power (at the detector) is ~8nW and should be compared with
the dc power of ~100nW consumed by the generator. The measured radiation
linewidth, as low as 1.1MHz, is typical for geometrical (Fiske) resonances
although we tried to suppress such resonances by placing well-matched microwave
transformers at its both ends. Making use of a phase-locking feedback loop we
are able to reduce the radiation linewidth to less than 1Hz measured relative
to the reference oscillator and defined just by the resolution of our
measurement setup.


title: Effect of Coulomb Screening Length on Nuclear Pasta Simulations

abstract:
  We study the role of the effective Coulomb interaction strength and length on
the dynamics of nucleons in conditions according to those in a neutron star's
crust. Calculations were made with a semi-classical molecular dynamics model,
studying isospin symmetric matter at sub-saturation densities and low
temperatures. The electrostatic interaction between protons interaction is
included in the form of a screened Coulomb potential in the spirit of the
Thomas-Fermi approximation, but the screening length is artificially varied to
explore its effect on the formation of the non-homogeneous nuclear structures
known as "nuclear pasta". As the screening length increases, we can a
transition from a one-per-cell pasta regime (due exclusively to finite size
effects) to a more appealing multiple pasta per simulation box. This shows
qualitative difference in the structure of neutron star matter at low
temperatures, and therefore, special caution should be taken when the screening
length is estimated for numerical simulations.


title:
Objets Sonores: Une Repr\'esentation Bio-Inspir\'ee Hi\'erarchique
  Parcimonieuse \`A Tr\`es Grandes Dimensions Utilisable En Reconnaissance;
  Auditory Objects: Bio-Inspired Hierarchical Sparse High Dimensional
  Representation for Recognition

abstract:
  L'accent est plac\'e dans cet article sur la structure hi\'erarchique,
l'aspect parcimonieux de la repr\'esentation de l'information sonore, la tr\`es
grande dimension des caract\'eristiques ainsi que sur l'ind\'ependance des
caract\'eristiques permettant de d\'efinir les composantes des objets sonores.
Les notions d'objet sonore et de repr\'esentation neuronale sont d'abord
introduites, puis illustr\'ees avec une application en analyse de signaux
sonores vari\'es: parole, musique et environnements naturels ext\'erieurs.
Finalement, un nouveau syst\`eme de reconnaissance automatique de parole est
propos\'e. Celui-ci est compar\'e \`a un syst\`eme statistique conventionnel.
Il montre tr\`es clairement que l'analyse par objets sonores introduit une
grande polyvalence et robustesse en reconnaissance de parole. Cette
int\'egration des connaissances en neurosciences et traitement des signaux
acoustiques ouvre de nouvelles perspectives dans le domaine de la
reconnaissance de signaux acoustiques.
  The emphasis is put on the hierarchical structure, independence and
sparseness aspects of auditory signal representations in high-dimensional
spaces, so as to define the components of auditory objects. The concept of an
auditory object and its neural representation is introduced. An illustrative
application then follows, consisting in the analysis of various auditory
signals: speech, music and natural outdoor environments. A new automatic speech
recognition (ASR) system is then proposed and compared to a conventional
statistical system. The proposed system clearly shows that an object-based
analysis introduces a great flexibility and robustness for the task of speech
recognition. The integration of knowledge from neuroscience and acoustic signal
processing brings new ways of thinking to the field of classification of
acoustic signals.


title: Scheduling a Cascade with Opposing Influences

abstract:
  Adoption or rejection of ideas, products, and technologies in a society is
often governed by simultaneous propagation of positive and negative influences.
Consider a planner trying to introduce an idea in different parts of a society
at different times. How should the planner design a schedule considering this
fact that positive reaction to the idea in early areas has a positive impact on
probability of success in later areas, whereas a flopped reaction has exactly
the opposite impact? We generalize a well-known economic model which has been
recently used by Chierichetti, Kleinberg, and Panconesi (ACM EC'12). In this
model the reaction of each area is determined by its initial preference and the
reaction of early areas. We generalize previous works by studying the problem
when people in different areas have various behaviors.
  We first prove, independent of the planner's schedule, influences help
(resp., hurt) the planner to propagate her idea if it is an appealing (resp.,
unappealing) idea. We also study the problem of designing the optimal
non-adaptive spreading strategy. In the non-adaptive spreading strategy, the
schedule is fixed at the beginning and is never changed. Whereas, in adaptive
spreading strategy the planner decides about the next move based on the current
state of the cascade. We demonstrate that it is hard to propose a non-adaptive
spreading strategy in general. Nevertheless, we propose an algorithm to find
the best non-adaptive spreading strategy when probabilities of different
behaviors of people in various areas drawn i.i.d from an unknown distribution.
Then, we consider the influence propagation phenomenon when the underlying
influence network can be any arbitrary graph. We show it is $\#P$-complete to
compute the expected number of adopters for a given spreading strategy.


title: On Matsumoto metrics of scale flag curvature

abstract:
  This paper contributes to the study of the Matsumoto metric F=alpha^2/beta,
where the alpha is a Riemannian metric and the beta is a one form. It is shown
that such a Matsumoto metric F is of scalar flag curvature if and only if F is
projectively flat.


title: Small clique number graphs with three trivial critical ideals

abstract:
  The critical ideals of a graph are the determinantal ideals of the
generalized Laplacian matrix associated to a graph. In this article we provide
a set of minimal forbidden graphs for the set of graphs with at most three
trivial critical ideals. Then we use these forbidden graphs to characterize the
graphs with at most three trivial critical ideals and clique number equal to 2
and 3.


title: Higgs mass from compositeness at a multi-TeV scale

abstract:
  Within composite Higgs models based on the top seesaw mechanism, we show that
the Higgs field can arise as the pseudo Nambu-Goldstone boson of the broken
U(3)_L chiral symmetry associated with a vector-like quark and the t-b doublet.
As a result, the lightest CP-even neutral state of the composite scalar sector
is lighter than the top quark, and can be identified as the newly discovered
Higgs boson. Constraints on weak isospin violation push the chiral symmetry
breaking scale above a few TeV, implying that other composite scalars are
probably too heavy to be probed at the LHC, but may be within reach at a future
hadron collider with center-of-mass energy of about 100 TeV.


title: Empirical electronic band structure study of silver low-index surfaces

abstract:
  We studied the electronic band structure of the low-index fcc Ag surfaces
(001), (110) and (111), by using the empirical tight-binding method in addition
with the surface Green function matching method. We report the energy values
for different surface and resonance states and compare with the available
experimental and theoretical data.


title:
A Continuous Refinement Strategy for the Multilevel Computation of
  Vertex Separators

abstract:
  The Vertex Separator Problem (VSP) on a graph is the problem of finding the
smallest collection of vertices whose removal separates the graph into two
disjoint subsets of roughly equal size. Recently, Hager and Hungerford [1]
developed a continuous bilinear programming formulation of the VSP. In this
paper, we reinforce the bilinear programming approach with a multilevel scheme
for learning the structure of the graph.


title:
Black hole remnant of black hole-neutron star coalescing binaries with
  arbitrary black hole spin

abstract:
  A model for determining the dimensionless spin parameter and mass of the
black hole remnant of black hole-neutron star mergers with arbitrary initial
black hole spin angular momentum, binary mass ratio, and neutron star mass and
cold equation of state is formulated. Tests against numerical-relativity
results are carried out, showing that both the dimensionless spin parameter and
the final mass are accurately reproduced. For the first time, the behaviour of
both quantities and of the l = 2, m = 2, n = 0 quasinormal mode frequency is
inspected throughout the parameter space. Predictions of this frequency may be
exploited to guide gravitational wave modelling and detection efforts, and to
extract physical information from detected gravitational wave signals that
would help us break degeneracies between binary black hole and black
hole-neutron star systems, improve our understanding of compact binary
formation, and constrain the neutron star equation of state.


title:
Strong ties promote the epidemic prevalence in
  susceptible-infected-susceptible spreading dynamics

abstract:
  Understanding spreading dynamics will benefit society as a whole in better
preventing and controlling diseases, as well as facilitating the socially
responsible information while depressing destructive rumors. In network-based
spreading dynamics, edges with different weights may play far different roles:
a friend from afar usually brings novel stories, and an intimate relationship
is highly risky for a flu epidemic. In this article, we propose a weighted
susceptible-infected-susceptible model on complex networks, where the weight of
an edge is defined by the topological proximity of the two associated nodes.
Each infected individual is allowed to select limited number of neighbors to
contact, and a tunable parameter is introduced to control the preference to
contact through high-weight or low-weight edges. Experimental results on six
real networks show that the epidemic prevalence can be largely promoted when
strong ties are favored in the spreading process. By comparing with two
statistical null models respectively with randomized topology and randomly
redistributed weights, we show that the distribution pattern of weights, rather
than the topology, mainly contributes to the experimental observations. Further
analysis suggests that the weight-weight correlation strongly affects the
results: high-weight edges are more significant in keeping high epidemic
prevalence when the weight-weight correlation is present.


title: Network Strategies in Election Campaigns

abstract:
  This study considers a simple variation of the voter model with two competing
parties. In particular, we represent the case of political elections, where
people can choose to support one of the two candidates or to remain neutral.
People operate within a social network and their opinions depend on those of
the people with whom they interact. Therefore, they may change their opinions
over time, which may mean supporting one particular candidate or none.
Candidates attempt to gain people's support by interacting with them, whether
they are in the same social circle (i.e. neighbors) or not. In particular,
candidates follow a strategy of interacting for a time with people they do not
know (that is, people who are not their neighbors). Our analysis of the
proposed model sought to establish which network strategies are the most
effective for candidates to gain popular support. We found that the most
suitable strategy depends on the topology of the social network. Finally, we
investigated the role of charisma in these dynamics. Charisma is relevant in
several social contexts, since charismatic people usually exercise a strong
influence over others. Our results showed that candidates' charisma is an
important contributory factor to a successful network strategy in election
campaigns.


title: Tipping Points in Schelling Segregation

abstract:
  One of the earliest agent-based economical models, Schelling's spacial
proximity model illustrated how global segregation can emerge, often unwanted,
from the actions of agents of two races acting in accordance with their
individual local preferences. Here a 1-dimensional unperturbed variant of the
model is studied, which is additionally open in the sense that agents may enter
and exit the model. Following the authors' previous work in [1] and that of
Brandt, Immorlica, Kamath, and Kleinberg in [2], rigorous results are
established, whose statements are asymptotic in both the model and
neighbourhood sizes.
  The current model's openness allows one race or the other to take over almost
everywhere in a measure-theoretic sense. Tipping points are identified between
the two regions of takeover and the region of staticity, in terms of the
parameters of the model. In a significant generalization from previous work,
the parameters comprise the initial proportions of the two races, along with
independent values of the tolerance for each race.


title: The Simplex Algorithm is NP-mighty

abstract:
  We propose to classify the power of algorithms by the complexity of the
problems that they can be used to solve. Instead of restricting to the problem
a particular algorithm was designed to solve explicitly, however, we include
problems that, with polynomial overhead, can be solved 'implicitly' during the
algorithm's execution. For example, we allow to solve a decision problem by
suitably transforming the input, executing the algorithm, and observing whether
a specific bit in its internal configuration ever switches during the
execution. We show that the Simplex Method, the Network Simplex Method (both
with Dantzig's original pivot rule), and the Successive Shortest Path Algorithm
are NP-mighty, that is, each of these algorithms can be used to solve any
problem in NP. This result casts a more favorable light on these algorithms'
exponential worst-case running times. Furthermore, as a consequence of our
approach, we obtain several novel hardness results. For example, for a given
input to the Simplex Algorithm, deciding whether a given variable ever enters
the basis during the algorithm's execution and determining the number of
iterations needed are both NP-hard problems. Finally, we close a long-standing
open problem in the area of network flows over time by showing that earliest
arrival flows are NP-hard to obtain.


title:
The effects of structure anisotropy on lensing observables in an exact
  general relativistic setting for precision cosmology

abstract:
  The study of relativistic, higher order and nonlinear effects has become
necessary in recent years in the pursuit of precision cosmology. We develop and
apply here a framework to study gravitational lensing in exact models in
general relativity that are not restricted to homogeneity and isotropy, and
where full nonlinearity and relativistic effects are included. We apply the
framework to a specific, anisotropic galaxy cluster model which is based on a
modified NFW halo density profile and described by the Szekeres metric. We
examine the effects of increasing levels of anisotropy in the galaxy cluster on
lensing observables like the convergence and shear for various lensing
geometries, finding a strong nonlinear response in both the convergence and
shear for rays passing through anisotropic regions of the cluster. Deviation
from the expected values in a spherically symmetric structure are asymmetric
with respect to path direction and thus will persist as a statistical effect
when averaged over some ensemble of such clusters. The resulting relative
difference in various geometries can be as large as approximately 2%, 8%, and
24% in the measure of convergence for levels of anisotropy of 5%, 10%, and 15%,
respectively, as a fraction of total cluster mass. For the total magnitude of
shear, the relative difference can grow near the center of the structure to be
as large as 15%, 32%, and 44% for the same levels of anisotropy, averaged over
the two extreme geometries. The convergence is impacted most strongly for rays
which pass in directions along the axis of maximum dipole anisotropy in the
structure, while the shear is most strongly impacted for rays which pass in
directions orthogonal to this axis, as expected. These effects due to
anisotropic structures will affect lensing measurements and must be fully
examined in an era of precision cosmology.


title:
Electron spin resonance and spin-valley physics in a silicon double
  quantum dot

abstract:
  Silicon quantum dots are a leading approach for solid-state quantum bits.
However, developing this technology is complicated by the multi-valley nature
of silicon. Here we observe transport of individual electrons in a silicon
CMOS-based double quantum dot under electron spin resonance. An anticrossing of
the driven dot energy levels is observed when the Zeeman and valley splittings
coincide. A detected anticrossing splitting of 60 MHz is interpreted as a
direct measure of spin and valley mixing, facilitated by spin-orbit interaction
in the presence of non-ideal interfaces. A lower bound of spin dephasing time
of 63 ns is extracted. We also describe a possible experimental evidence of an
unconventional spin-valley blockade, despite the assumption of non-ideal
interfaces. This understanding of silicon spin-valley physics should enable
better control and read-out techniques for the spin qubits in an all CMOS
silicon approach.


title: Anisotropic Intermittency of Magnetohydrodynamic Turbulence

abstract:
  A higher-order multiscale analysis of spatial anisotropy in inertial range
magnetohydrodynamic turbulence is presented using measurements from the STEREO
spacecraft in fast ambient solar wind. We show for the first time that, when
measuring parallel to the local magnetic field direction, the full statistical
signature of the magnetic and Els\"asser field fluctuations is that of a
non-Gaussian globally scale-invariant process. This is distinct from the
classic multi-exponent statistics observed when the local magnetic field is
perpendicular to the flow direction. These observations are interpreted as
evidence for the weakness, or absence, of a parallel magnetofluid turbulence
energy cascade. As such, these results present strong observational constraints
on the statistical nature of intermittency in turbulent plasmas.


title: Hypergeometric tail inequalities: ending the insanity

abstract:
  The hypergeometric distribution is briefly and informally surveyed, including
popular notation, symmetries, and the tail inequalities $Pr[i \ge E[i]+tn] \le
e^{-2t^2n}$ and $Pr[i \le E[i]-tn] \le e^{-2t^2n}$.


title:
Genuine tripartite entanglement and nonlocality in Bose-Einstein
  condensates by collective atomic recoil

abstract:
  We study a system represented by a Bose-Einstein condensate interacting with
a cavity field in presence of a strong off-resonant pumping laser. This system
can be described by a three-mode Gaussian state, where two are the atomic modes
corresponding to atoms populating upper and lower momentum sidebands and the
third mode describes the scattered cavity field light. We show that, as a
consequence of the collective atomic recoil instability, these modes possess a
genuine tripartite entanglement that increases unboundedly with the evolution
time and is larger than the bipartite entanglement in any reduced two-mode
bipartition. We further show that the state of the system exhibits genuine
tripartite nonlocality, which can be revealed by a robust violation of the
Svetlichny inequality when performing displaced parity measurements. Our exact
results are obtained by exploiting the powerful machinery of phase-space
informational measures for Gaussian states, which we briefly review in the
opening sections of the paper.


title: Discovery of the Young L Dwarf WISE J1741102.78-464225.5

abstract:
  We report the discovery of the L dwarf WISE J174102.78$-$464225.5, that was
discovered as part of a search for nearby L dwarfs using the Wide-field
Infrared Survey Explorer (WISE). The distinct triangular peak of the H-band
portion of its near-infrared spectrum and its red near-infrared colors ($J-K_S$
= 2.35$\pm$0.08 mag) are indicative of a young age. Via comparison to spectral
standards and other red L dwarfs, we estimate a near-infrared spectral type to
be L7$\pm$2 (pec). From a comparison to spectral and low-mass evolutionary
models, we determine self-consistent effective temperature, log $g$, age, and
mass values of 1450$\pm$100 K, 4.0$\pm$0.25 (cm s$^{-2}$), 10-100 Myr, and 4-21
M$_{Jup}$, respectively. With an estimated distance of 10-30 pc, we explore the
possibility that WISE J174102.78-464225.5 belongs to one of the young nearby
moving groups via a kinematic analysis and we find potential membership in the
$\beta$ Pictoris or AB Doradus associations. A trigonometric parallax
measurement and a precise radial velocity can help to secure its membership in
either of these groups.


title:
Nonexistence of Exceptional 5-class Association Schemes with Two
  $Q$-polynomial Structures

abstract:
  In [H. Suzuki, Association schemes with multiple $Q$-polynomial structures,
J. Algebraic Combin. 7 (1998) 181-196], Suzuki gave a classification of
association schemes with multiple $Q$-polynomial structures, allowing for one
exceptional case which has five classes. In this paper, we rule out the
existence of this case. Hence Suzuki's theorem mirrors exactly the well-known
counterpart for association schemes with multiple $P$-polynomial structures, a
result due to Eiichi Bannai and Etsuko Bannai in 1980.


title:
A new investigation of oxygen flow influence on ITO thin films by
  magnetron sputtering

abstract:
  ITO thin films were deposited on glass substrates by d.c. magnetron
sputtering with varied oxygen flow rates. It was found that the optical
absorption decreases and optical absorption edge has blue shifts with the
increasing oxygen flow rate. Oxygen vacancy concentration was characterized and
analyzed by XPS. It is shown that the oxygen vacancy concentration increases
with oxygen flow rates, which is a different observation from the current
understanding. The energy band structures associated with different vacancy
concentrations of ITO were calculated using the first-principle based on
density functional theory. The calculation results show that the increase of
oxygen vacancies induces the increase of bands below Fermi level as well as the
presence of a second band gap, which accounts for effects of the oxygen
vacancies on the blue shifts.


title: Updating an upper bound of Erik Westzynthius

abstract:
  Inspired by a paper of Erik Westzynthius,we build on work of Harlan Stevens
and Hans-Joachim Kanold. Let $k \gt 2$ be the number of distinct prime divisors
of a positive integer $n$. In 1977, Stevens used Bonferroni inequalities to get
an explicit upper bound on Jacobsthal's function $g(n)$, which is related to
the size of largest interval of consecutive integers none of which are coprime
to $n$. Letting $u(k)$ be the base $2$ $\log$ of this bound, Stevens showed
$u(k)$ is $O((\log k)^2)$, improving upon Kanold's exponent $O(\sqrt{k})$. We
use elementary methods similar to those of Stevens to get $u(k)$ is $O(\log
k(\log\log k))$ in one form and $O(\sigma^{-1}(n)\log k)$ in another form. We
also show how these bounds can be improved for small $k$.


title: Mixing under monotone censoring

abstract:
  We initiate the study of mixing times of Markov chain under monotone
censoring. Suppose we have some Markov Chain $M$ on a state space $\Omega$ with
stationary distribution $\pi$ and a monotone set $A \subset \Omega$. We
consider the chain $M'$ which is the same as the chain $M$ started at some $x
\in A$ except that moves of $M$ of the form $x \to y$ where $x \in A$ and $y
\notin A$ are {\em censored} and replaced by the move $x \to x$. If $M$ is
ergodic and $A$ is connected, the new chain converges to $\pi$ conditional on
$A$. In this paper we are interested in the mixing time of the chain $M'$ in
terms of properties of $M$ and $A$. Our results are based on new connections
with the field of property testing. A number of open problems are presented.


title:
Simulation and Analysis of TE Wave Propagation as a Probe for Electron
  Clouds in Particle Accelerators

abstract:
  The use of transverse electric (TE) waves has proved to be a powerful,
noninvasive method for estimating the densities of electron clouds formed in
particle accelerators. Results from the plasma simulation program VORPAL have
been a useful guide for experimental studies related to this method, which have
been performed at various accelerator facilities. This paper provides results
of the simulation and modeling work done in conjunction with experimental
efforts carried out at CesrTA. The discussion starts from the phase shift
induced by electron clouds in the transmission of the wave, followed by the
effect of reflections along the beam-pipe, the simulation of the resonant wave
method and the effects of external magnetic fields, namely dipoles and
wigglers. A derivation of the dispersion relationship of wave propagation for
arbitrary geometries in field free regions with a uniform cloud density is also
provided.


title:
Fast Training of Effective Multi-class Boosting Using Coordinate Descent
  Optimization

abstract:
  Wepresentanovelcolumngenerationbasedboostingmethod for multi-class
classification. Our multi-class boosting is formulated in a single optimization
problem as in Shen and Hao (2011). Different from most existing multi-class
boosting methods, which use the same set of weak learners for all the classes,
we train class specified weak learners (i.e., each class has a different set of
weak learners). We show that using separate weak learner sets for each class
leads to fast convergence, without introducing additional computational
overhead in the training procedure. To further make the training more efficient
and scalable, we also propose a fast co- ordinate descent method for solving
the optimization problem at each boosting iteration. The proposed coordinate
descent method is conceptually simple and easy to implement in that it is a
closed-form solution for each coordinate update. Experimental results on a
variety of datasets show that, compared to a range of existing multi-class
boosting meth- ods, the proposed method has much faster convergence rate and
better generalization performance in most cases. We also empirically show that
the proposed fast coordinate descent algorithm needs less training time than
the MultiBoost algorithm in Shen and Hao (2011).


title: Quantum realization of arbitrary joint measurability structures

abstract:
  In many a traditional physics textbook, a quantum measurement is defined as a
projective measurement represented by a Hermitian operator. In quantum
information theory, however, the concept of a measurement is dealt with in
complete generality and we are therefore forced to confront the more general
notion of positive-operator valued measures (POVMs) which suffice to describe
all measurements that can be implemented in quantum experiments. We study the
(in)compatibility of such POVMs and show that quantum theory realizes all
possible (in)compatibility relations among sets of POVMs. This is in contrast
to the restricted case of projective measurements for which commutativity is
essentially equivalent to compatibility. Our result therefore points out a
fundamental feature with respect to the (in)compatibility of quantum
observables that has no analog in the case of projective measurements.


title: GoFFish: A Sub-Graph Centric Framework for Large-Scale Graph Analytics

abstract:
  Large scale graph processing is a major research area for Big Data
exploration. Vertex centric programming models like Pregel are gaining traction
due to their simple abstraction that allows for scalable execution on
distributed systems naturally. However, there are limitations to this approach
which cause vertex centric algorithms to under-perform due to poor compute to
communication overhead ratio and slow convergence of iterative superstep. In
this paper we introduce GoFFish a scalable sub-graph centric framework
co-designed with a distributed persistent graph storage for large scale graph
analytics on commodity clusters. We introduce a sub-graph centric programming
abstraction that combines the scalability of a vertex centric approach with the
flexibility of shared memory sub-graph computation. We map Connected
Components, SSSP and PageRank algorithms to this model to illustrate its
flexibility. Further, we empirically analyze GoFFish using several real world
graphs and demonstrate its significant performance improvement, orders of
magnitude in some cases, compared to Apache Giraph, the leading open source
vertex centric implementation.


title: Davies type estimate and the heat kernel bound under the Ricci flow

abstract:
  We prove a Davies type double integral estimate for the heat kernel
$H(y,t;x,l)$ under the Ricci flow. As a result, we give an affirmative answer
to a question proposed by Chow etc.. Moreover, we apply the Davies type
estimate to provide a new proof of the Gaussian upper and lower bounds of
$H(y,t;x,l)$ which were first shown by Chau-Tam-Yu.


title: Dynamics of Quantum Fisher information in a spin-boson model

abstract:
  Quantum Fisher information characterizes the phase sensitivity of qubits in
the spin-boson model with a finite bandwidth spectrum. In contrast with
Markovian reservoirs, the quantum Fisher information will flow from the
environments to qubits after some times if the bath parameter $s$ is larger
than a critical value which is related to temperatures. The sudden change
behavior will happen during the evolution of the quantum Fisher information of
the maximal entanglement state in the non-Markovian environments. The sudden
change times can be varied with the change of the bath parameter $s$. For a
very large number of entangled qubits, the sudden change behavior of the
maximal quantum Fisher information can be used to characterize the existence of
the entanglement. The metrology strategy based on the quantum correlated state
leads to a lower phase uncertainty when compared to the uncorrelated product
state.


title:
Nonunital non-Markovian dynamics induced by a spin bath and interplay of
  quantum Fisher information

abstract:
  We explore the nonunital non-Markovian dynamics of a qubit immersed in a spin
bath. The nonunital environmental effects on the precisions of quantum
parameter estimation are investigated. The time-dependent transfer matrix and
inhomogeneity vector are obtained for the description of the open dynamical
process. The evolution of the coherent vectors for a qubit is studied so as to
geometrically demonstrate the nonunital non-Markovian effects. The revivals of
angles for the fidelity between a maximal mixed state and an arbitrary
trajectory state are presented in the nonunital non-Markovian dynamics. The
degree for the nonunitality is controllable with the changes of the local
magnetic field for a qubit and spin bath temperature. It is found out that the
increase of quantum Fisher information for composite states is connected with
the nonunital non-Markovian effects, which is helpful for the improvement of
quantum metrology.


title:
Finite-temperature decoherence of spin states in a
  $\texttt{\{}\emph{Cu}_3\texttt{\}}$ single molecular magnet

abstract:
  We investigate the quantum evolution of spin states of a single molecular
magnet in a local electric field. The decoherence of a
$\texttt{\{}\emph{Cu}_3\texttt{\}}$ single molecular magnet weakly coupled to a
thermal bosonic environment can be analyzed by the spin-boson model. Using the
finite-temperature time-convolutionless quantum master equation, we obtain the
analytical expression of the reduced density matrix of the system in the
secular approximation. The suppressed and revived dynamical behavior of the
spin states are presented by the oscillation of the chirality spin polarization
on the time scale of the correlation time of the environment. The quantum
decoherence can be effectively restrained with the help of the manipulation of
local electric field and the environment spectral density function. Under the
influence of the dissipation, the pointer states measured by the von Neumann
entropy are calculated to manifest the entanglement property of the
system-environment model.


title: Robust Vertex Classification

abstract:
  For random graphs distributed according to stochastic blockmodels, a special
case of latent position graphs, adjacency spectral embedding followed by
appropriate vertex classification is asymptotically Bayes optimal; but this
approach requires knowledge of and critically depends on the model dimension.
In this paper, we propose a sparse representation vertex classifier which does
not require information about the model dimension. This classifier represents a
test vertex as a sparse combination of the vertices in the training set and
uses the recovered coefficients to classify the test vertex. We prove
consistency of our proposed classifier for stochastic blockmodels, and
demonstrate that the sparse representation classifier can predict vertex labels
with higher accuracy than adjacency spectral embedding approaches via both
simulation studies and real data experiments. Our results demonstrate the
robustness and effectiveness of our proposed vertex classifier when the model
dimension is unknown.


title:
The obstacle and Dirichlet problems associated with p-harmonic functions
  in unbounded sets in Rn and metric spaces

abstract:
  We study the obstacle problem for unbounded sets in a proper metric measure
space supporting a (p,p)-Poincare inequality. We prove that there exists a
unique solution. We also prove that if the measure is doubling and the obstacle
is continuous, then the solution is continuous, and moreover p-harmonic in the
set where it does not touch the obstacle. This includes, as a special case, the
solution of the Dirichlet problem for p-harmonic functions with Sobolev type
boundary data.


title:
Consensus in continuous-time multi-agent systems under discontinuous
  nonlinear protocols

abstract:
  In this paper, we provide a theoretical analysis for nonlinear discontinuous
consensus protocols in networks of multiagents over weighted directed graphs.
By integrating the analytic tools from nonsmooth stability analysis and graph
theory, we investigate networks with both fixed topology and randomly switching
topology. For networks with a fixed topology, we provide a sufficient and
necessary condition for asymptotic consensus, and the consensus value can be
explicitly calculated. As to networks with switching topologies, we provide a
sufficient condition for the network to realize consensus almost surely.
Particularly, we consider the case that the switching sequence is independent
and identically distributed. As applications of the theoretical results, we
introduce a generalized blinking model and show that consensus can be realized
almost surely under the proposed protocols. Numerical simulations are also
provided to illustrate the theoretical results.


title:
Differentiation of Bulk and Surface Events in p-type Point-Contact
  Germanium Detectors for Light WIMP Searches

abstract:
  The p-type point-contact germanium detectors are novel techniques offering
kg-scale radiation sensors with sub-keV sensitivities. They have been used for
light Dark Matter WIMPs searches and may have potential applications in
neutrino physics. There are, however, anomalous surface behaviour which needs
to be characterized and understood. We describe the methods and results of a
research program whose goals are to identify the bulk and surface events via
software pulse shape analysis techniques, and to devise calibration schemes to
evaluate the selection efficiency factors. Efficiencies-corrected background
spectra from the low-background facility at Kuo-Sheng Neutrino Laboratory are
derived.


title:
A New Method for Measuring Coherent Elastic Neutrino Nucleus Scattering
  at an Off-Axis High-Energy Neutrino Beam Target

abstract:
  We present a new experimental method for measuring the process of Coherent
Elastic Neutrino Nucleus Scattering (CENNS). This method uses a detector
situated transverse to a high energy neutrino beam production target. This
detector would be sensitive to the low energy neutrinos arising from pion
decays-at-rest in the target. We discuss the physics motivation for making this
measurement and outline the predicted backgrounds and sensitivities using this
approach. We report a measurement of neutron backgrounds as found in an
off-axis surface location of the Fermilab Booster Neutrino Beam (BNB) target.
The results indicate that the Fermilab BNB target is a favorable location for a
CENNS experiment.