title:
NNLO QCD Corrections to the Drell-Yan Cross Section in Models of
  TeV-Scale Gravity

abstract:
  The first results on the complete next-to-next-to-leading order (NNLO)
Quantum Chromodynamic (QCD) corrections to the production of di-leptons at
hadron colliders in large extra dimension models with spin-2 particles are
reported in this article. In particular, we have computed these corrections to
the invariant mass distribution of the di-leptons taking into account all the
partonic subprocesses that contribute at NNLO. In these models, spin-2
particles couple through the energy-momentum tensor of the Standard Model (SM)
with the universal coupling strength. The tensorial nature of the interaction
and the presence of both quark annihilation and gluon fusion channels at the
Born level make it challenging computationally and interesting
phenomenologically. We have demonstrated numerically the importance of our
results at the Large Hadron Collider (LHC) energies. The two loop corrections
contribute an additional 10\% to the total cross section. We find that the QCD
corrections are not only large but also important to make the predictions
stable under renormalisation and factorisation scale variations providing an
opportunity to stringently constrain the parameters of the models with a spin-2
particle.


title: Anomaly detection in video with Bayesian nonparametrics

abstract:
  A novel dynamic Bayesian nonparametric topic model for anomaly detection in
video is proposed in this paper. Batch and online Gibbs samplers are developed
for inference. The paper introduces a new abnormality measure for decision
making. The proposed method is evaluated on both synthetic and real data. The
comparison with a non-dynamic model shows the superiority of the proposed
dynamic one in terms of the classification performance for anomaly detection.


title:
Proof of the Brou\'e-Malle-Rouquier conjecture in characteristic zero
  (after I. Losev and I. Marin - G. Pfeiffer)

abstract:
  In 1998 Brou\'e, Malle and Rouquier conjectured that the Hecke algebra of a
finite complex reflection group W is a free module over the algebra of
parameters of rank |W|. We give an exposition of a proof of this conjecture in
characteristic zero (and sufficiently large positive characteristic), due to I.
Losev and I. Marin - G. Pfeiffer.


title:
Motion of charged particles in a NUTty Einstein-Maxwell spacetime and
  causality violation

abstract:
  We investigate the motion of electrically charged test particles in
spacetimes with closed timelike curves, a subset of the black hole or wormhole
Reissner-Nordstr\"om-NUT spacetimes without periodic identification of time. We
show that, while in the wormhole case there are closed worldlines inside a
potential well, the wordlines of initially distant charged observers moving
under the action of the Lorentz force can never close or self-intersect. This
means that for these observers causality is preserved, which is an instance of
our weak chronology protection criterion.


title: Magnetoelectric coupling in superconductor-helimagnet heterostructures

abstract:
  The Ginzburg-Landau free energy of a conventional superconductor coupled to a
helimagnet is microscopically derived using functional field integral
techniques. We show that the spin texture leads to a Lifshitz invariant in the
free energy, which couples the momentum density of the superconducting
condensate to the magnetization of the helimagnet. For helimagnets with a
conical texture, the Lifshitz invariant yields a spatial modulation of the
superconducting phase along the helical wavevector of the magnetic texture.
Based on self-consistent numerical calculations, we verify the theoretical
formalism by investigating a superconductor that contains a helical
Yu-Shiba-Rusinov (YSR) chain. We demonstrate that the texture-induced
magnetoelectric coupling produces a strong supercurrent along the YSR chain,
which induces a detectable magnetic field.


title: Gaussian ensemble for quantum integrable dynamics

abstract:
  We propose a Gaussian ensemble as a description of the long-time dynamics of
isolated quantum integrable systems. Our approach extends the Generalized Gibbs
Ensemble (GGE) by incorporating fluctuations of integrals of motion. It is
asymptotically exact in the classical limit irrespective of the system size
and, under appropriate conditions, in the thermodynamic limit irrespective of
the value of Planck's constant. Moreover, it captures quantum corrections near
the classical limit, finite size corrections near the thermodynamic limit, and
is valid in the presence of non-local interactions. The Gaussian ensemble
bridges the gap between classical integrable systems, where a generalized
microcanonical ensemble is exact even for few degrees of freedom and GGE, which
requires thermodynamic limit. We illustrate our results with examples of
increasing complexity.


title:
Nodal versus nodeless superconductivity in iso-electronic LiFeP and
  LiFeAs

abstract:
  Nodal superconductivity is observed in LiFeP while its counterpart LiFeAs
with similar topology and orbital content of the Fermi surfaces is a nodeless
superconductor. We explain this difference by solving, in the two-Fe Brillouin
zone, the frequency-dependent Eliashberg equations with spin-fluctuation
mediated pairing interaction. Because of Fermi surface topology details, in
LiFeAs all the Fe-$t_{2g}$ orbitals favor a common pairing symmetry. By
contrast, in LiFeP the $d_{xy}$ orbital favors a pairing symmetry different
from $d_{xz/yz}$ and their competition determines the pairing symmetry and the
strength of the superconducting instability: $d_{xy}$ orbital strongly
overcomes the others and imposes the symmetry of the superconducting order
parameter. The leading pairing channel is a $d_{xy}$-type state with nodes on
both hole and electron Fermi surfaces. As a consequence, the $d_{xz/yz}$
electrons weakly pair leading to a reduced transition temperature in LiFeP.


title:
Acceleration of cometary dust near the nucleus: Application to
  67P/Churyumov-Gerasimenko

abstract:
  We present a model of cometary dust capable of simulating the dynamics within
the first few tens of km of the comet surface. Recent measurements by the GIADA
and COSIMA instruments on Rosetta show that the nucleus emits fluffy dust
particles with porosities above 50% and sizes up to at least mm (Schulz et al.
2015, Rotundi et al. 2015, Fulle et al. 2015). Retrieval of the physical
properties of these particles requires a model of the effective forces
governing their dynamics. Here, we present a model capable of simulating
realistic, large and porous particles using hierarchical aggregates, which
shows previous extrapolations to be inadequate. The main strengths of our
approach are that we can simulate very large (mm-scale) non-spherical
agglomerates and can accurately determine their 1) effective cross-section and
ratio of cross-section to mass, 2) gas drag coefficient, and 3) light
scattering properties. In practical terms, we find that a more detailed
treatment of the dust structure results in 3-5 times higher velocities for
large dust particles in the inner coma than previously estimated using
spherical particles of the same mass. We apply our model to the dynamics of
dust in the vicinity of the nucleus of comet 67P and successfully reproduce the
dust speeds reported early on when the comet was roughly 3.5 AU from the Sun.
At this stage, we employ a simple spherical comet nucleus, we model activity as
constant velocity gas expansion from a uniformly active surface, and use Mie
scattering. We discuss pathways to improve on these simplifications in the
future.


title: Graviton Mass Bounds

abstract:
  Recently, aLIGO has announced the first direct detections of gravitational
waves, a direct manifestation of the propagating degrees of freedom of gravity.
The detected signals GW150914 and GW151226 have been used to examine the basic
properties of these gravitational degrees of freedom, particularly setting an
upper bound on their mass. It is timely to review what the mass of these
gravitational degrees of freedom means from the theoretical point of view,
particularly taking into account the recent developments in constructing
consistent massive gravity theories. Apart from the GW150914 mass bound, a few
other observational bounds have been established from the effects of the Yukawa
potential, modified dispersion relation and fifth force that are all induced
when the fundamental gravitational degrees of freedom are massive. We review
these different mass bounds and examine how they stand in the wake of recent
theoretical developments and how they compare to the bound from GW150914.


title: NNLO QCD Corrections to t-channel Single Top-Quark Production and Decay

abstract:
  We present a fully differential next-to-next-to-leading order calculation of
t-channel single top-quark production and decay at the LHC under narrow-width
approximation and neglecting cross-talk between incoming protons. We focus on
the fiducial cross sections at 13 TeV, finding that the next-to-next-to-leading
order QCD corrections can reach the level of -6%. The scale variations are
reduced to the level of a percent. Our results can be used to improve
experimental acceptance estimates and the measurements of the single top-quark
production cross section and the top-quark electroweak couplings.


title: Molecular clouds photoevaporation and FIR line emission

abstract:
  With the aim of improving predictions on far infrared (FIR) line emission
from Giant Molecular Clouds (GMC), we study the effects of photoevaporation
(PE) produced by external far-ultraviolet (FUV) and ionizing
(extreme-ultraviolet, EUV) radiation on GMC structure. We consider three
different GMCs with mass in the range $M_{\rm GMC} = 10^{3-6}\,\rm{M_{\odot}}$.
Our model includes: (i) an observationally-based inhomogeneous GMC density
field, and (ii) its time evolution during the PE process. In the fiducial case
($M_{\rm GMC}\approx10^5 M_{\odot}$), the photoevaporation time ($t_{pe}$)
increases from 1 Myr to 30 Myr for gas metallicity $Z=0.05-1\,\rm Z_{\odot}$,
respectively. Next, we compute the time-dependent luminosity of key FIR lines
tracing the neutral and ionized gas layers of the GMCs, ([CII] at $158\,\rm{\mu
m}$, [OIII] at $88\,\rm \mu m$) as a function of $G_0$, and $Z$ until complete
photoevaporation at $t_{pe}$. We find that the specific [CII] luminosity is
almost independent on the GMC model within the survival time of the cloud.
Stronger FUV fluxes produce higher [CII] and [OIII] luminosities, however
lasting for progressively shorter times. At $Z=Z_{\odot}$ the [CII] emission is
maximized ($L_{\rm CII}\approx 10^4\,\rm{L_{\odot}}$ for the fiducial model)
for $t<1\,\rm{Myr}$ and $\log G_0\geq 3$. Noticeably, and consistently with the
recent detection by Inoue et al. (2016) of a galaxy at redshift $z\approx 7.2$,
for $Z\leq 0.2\,\rm{Z_{\odot}}$ the [OIII] line might outshine [CII] emission
by up to $\approx 1000$ times. We conclude that the [OIII] line is a key
diagnostic of low metallicity ISM, especially in galaxies with very young
stellar populations.


title: General theory of many body localized systems coupled to baths

abstract:
  We consider what happens when a many body localized system is coupled to a
heat bath. Unlike previous works, we do not restrict ourselves to the limit
where the bath is large and effectively Markovian, nor to the limit where back
action on the bath is negligible. We identify limits where the effect of the
bath can be captured by classical noise, and limits where it cannot. We also
identify limits in which the bath delocalizes the system, as well as limits in
which the system localizes the bath. Using general arguments and dimensional
analysis, we constrain the overall phase diagram of the coupled system and
bath. Our analysis incorporates all the previously discussed regimes, and also
uncovers a new intrinsically quantum regime that has not hitherto been
discussed. We discuss baths that are themselves near a localization transition,
or are strongly disordered but protected against localization by symmetry or
topology. We also discuss situations where the system and bath have different
dimensionality (the case of `boundary MBL' and `boundary baths').


title:
Information and backaction due to phase contrast imaging measurements of
  cold atomic gases: beyond Gaussian states

abstract:
  We further examine a theory of phase contrast imaging (PCI) of cold atomic
gases, first introduced by us in Phys. Rev. Lett. {\bf 112}, 233602 (2014). We
model the PCI measurement by directly calculating the entangled state between
the light and the atoms due to the ac Stark shift, which induces a conditional
phase shift on the light depending upon the atomic state. By interfering the
light that passes through the BEC with the original light, one can obtain
information of the atomic state at a single shot level. We derive an exact
expression for a measurement operator that embodies the information obtained
from PCI, as well as the back-action on the atomic state. By the use of exact
expressions for the measurement process, we go beyond the continuous variables
approximation such that the non-Gaussian regime can be accessed for both the
measured state and the post-measurement state. Features such as the photon
probability density, signal, signal variance, Fisher information, error of the
measurement, and the backaction are calculated by applying the measurement
operator to an atomic two spin state system. For an atomic state that is
initially in a spin coherent state, we obtain analytical expression for these
quantities. There is an optimal atom-light interaction time that scales
inversely proportional to the number of atoms, which maximizes the information
readout.


title: Inner Functions in certain Hardy-Sobolev Spaces

abstract:
  For $1/2<p<1$, a description of inner functions whose derivative is in the
Hardy space $H^p$ is given in terms of either their mapping properties or the
geometric distribution of their zeros.


title:
Dynamical Symmetry Breaking in Chiral Gauge Theories with Direct-Product
  Gauge Groups

abstract:
  We analyze patterns of dynamical symmetry breaking in strongly coupled chiral
gauge theories with direct-product gauge groups $G$. If the gauge coupling for
a factor group $G_i \subset G$ becomes sufficiently strong, it can produce
bilinear fermion condensates that break the $G_i$ symmetry itself and/or break
other gauge symmetries $G_j \subset G$. Our comparative study of a number of
strongly coupled direct-product chiral gauge theories elucidates how the
patterns of symmetry breaking depend on the structure of $G$ and on the
relative sizes of the gauge couplings corresponding to factor groups in the
direct product.


title:
A simple and general method for solving detailed chemical evolution with
  delayed production of iron and other chemical elements

abstract:
  We present a theoretical method for solving the chemical evolution of
galaxies, by assuming an instantaneous recycling approximation for chemical
elements restored by massive stars and the Delay Time Distribution formalism
for the delayed chemical enrichment by Type Ia Supernovae. The galaxy gas mass
assembly history, together with the assumed stellar yields and initial mass
function, represent the starting point of this method. We derive a simple and
general equation which closely relates the Laplace transforms of the galaxy gas
accretion history and star formation history, which can be used to simplify the
problem of retrieving these quantities in the galaxy evolution models assuming
a linear Schmidt-Kennicutt law. We find that - once the galaxy star formation
history has been reconstructed from our assumptions - the differential equation
for the evolution of the chemical element $X$ can be suitably solved with
classical methods. We apply our model to reproduce the [O/Fe] and [Si/Fe] vs.
[Fe/H] chemical abundance patterns as observed at the solar neighborhood, by
assuming a decaying exponential infall rate of gas and different delay time
distributions for Type Ia Supernovae; we also explore the effect of assuming a
nonlinear Schmidt-Kennicutt law, with the index of the power law being $k=1.4$.
Although approximate, we conclude that our model with the single degenerate
scenario for Type Ia Supernovae provides the best agreement with the observed
set of data. Our method can be used by other complementary galaxy stellar
population synthesis models to predict also the chemical evolution of galaxies.


title: Supercurrent-Induced Spin-Orbit Torques

abstract:
  We theoretically investigate the supercurrent-induced magnetization dynamics
of a two-dimensional lattice of ferromagnetically ordered spins placed on a
conventional superconductor with broken spatial inversion symmetry and strong
spin-orbit coupling. We develop a phenomenological description of the coupled
dynamics of the superconducting condensate and the spin system, and demonstrate
that supercurrents produce a reactive spin-orbit torque on the magnetization.
By performing a microscopic self-consistent calculation, we show that the
spin-orbit torque originates from a spin-polarization of the Cooper pairs due
to current-induced spin-triplet correlations. Interestingly, we find that there
exists an intrinsic limitation for the maximum achievable spin-orbit torque,
which is determined by the coupling strength between the condensate and the
spin system. In proximitized hole-doped semiconductors, the maximum achievable
spin-orbit torque field is estimated to be on the order of $0.16$ mT, which is
comparable to the critical field for current-induced magnetization switching in
ferromagnetic semiconductors.


title:
Fractional NLS equations with magnetic field, critical frequency and
  critical growth

abstract:
  The paper is devoted to the study of a singularly perturbed fractional
Schr\"{o}dinger equations involving critical frequency and critical growth in
the presence of a magnetic field. By using variational methods, we obtain the
existence of mountain pass solutions $u_{\varepsilon}$ which tend to the
trivial solution as $\varepsilon\rightarrow0$. Moreover, we get infinitely many
solutions and sign-changing solutions for the problem in absence of magnetic
effects under some extra assumptions.


title: NIP henselian valued fields

abstract:
  We show that any theory of tame henselian valued fields is NIP if and only if
the theory of its residue field and the theory of its value group are NIP.
Moreover, we show that if $(K,v)$ is a henselian valued field of residue
characteristic $\mathrm{char}(Kv)=p$ for which $K^\times/(K^\times)^p$ is
finite in case $p>0$, then $(K,v)$ is NIP iff $Kv$ is NIP and $v$ is roughly
tame.


title: Topological spin ordering via Chern-Simons superconductivity

abstract:
  We use the Chern-Simons (CS) fermion representation of s =1/2 spin operators
to construct topological, long-range magnetically ordered states of interacting
two-dimensional (2D) quantum spin models. We show that the fermion-fermion
interactions mediated by the dynamic CS flux attachment may give rise to Cooper
pairing of the fermions. Specifically, in an XY model on the honeycomb lattice,
this construction leads to a "CS superconductor," which belongs to a
topologically non-trivial in 2D symmetry class DIII, with particle-hole and
time-reversal symmetries. It is shown that in the original spin language, this
state corresponds to a symmetry protected topological state, which coexists
with a magnetic long-range order. We discuss physical manifestations of the
topological character of the corresponding state and requirements for models
that could host it.


title: Magnetogenesis from axion inflation

abstract:
  In this work we compute the production of magnetic fields in models of axion
inflation coupled to the hypercharge sector of the Standard Model through a
Chern-Simons interaction term. We make the simplest choice of a quadratic
inflationary potential and use lattice simulations to calculate the magnetic
field strength, helicity and correlation length at the end of inflation. For
small values of the axion-gauge field coupling strength the results agree with
no-backreaction calculations and estimates found in the literature. For larger
couplings the helicity of the magnetic field differs from the no-backreaction
estimate and depends strongly on the comoving wavenumber. We estimate the
post-inflationary evolution of the magnetic field based on known results for
the evolution of helical and non-helical magnetic fields. The magnetic fields
produced by axion inflation with large couplings to $U(1)_Y$ can reach $B_{\rm
eff} \gtrsim 10^{-16}\, {\rm G}$, exhibiting a field strength $B_{\rm phys}
\approx 10^{-13}\, {\rm G}$ and a correlation length $\lambda_{\rm
phys}\approx10\, {\rm pc}$. This result is insensitive to the exact value of
the coupling, as long as the coupling is large enough to allow for
instantaneous preheating. Depending on the assumptions for the physical
processes that determine blazar properties, these fields can be found
consistent with blazar observations based on the value of $B_{\rm eff}$.
Finally, the intensity of the magnetic field for large coupling can be enough
to satisfy the requirements for a recently proposed baryogenesis mechanism,
which utilizes the chiral anomaly of the Standard Model.


title:
A deterministic projector configuration interaction approach for the
  ground state of quantum many-body systems

abstract:
  In this work we propose a novel approach to solve the Schr\"{o}dinger
equation which combines projection onto the ground state with a path-filtering
truncation scheme. The resulting projector configuration interaction (PCI)
approach realizes a deterministic version of the full configuration interaction
quantum Monte Carlo (FCIQMC) method [Booth, G. H.; Thom, A. J. W.; Alavi, A. J.
Chem. Phys. 2009, 131, 054106]. To improve upon the linearized imaginary-time
propagator, we develop an optimal projector scheme based on an exponential
Chebyshev expansion in the limit of an infinite imaginary time step. After
writing the exact projector as a path integral in determinant space, we
introduce a path filtering procedure that truncates the size of the
determinantal basis and approximates the Hamiltonian. The path filtering
procedure is controlled by one real threshold that determines the accuracy of
the PCI energy and is not biased towards any determinant. Therefore, the PCI
approach can equally well describe static and dynamic electron correlation.
This point is illustrated in benchmark computation on N$_2$ at both equilibrium
and stretched geometries. In both cases, the PCI achieves chemical accuracy
with wave functions that contain less than 0.5% of the full CI space. We also
report computations on the ground state of C$_2$ with up to quaduple-$\zeta$
basis sets and wave functions as large as 200 million determinants, which allow
a direct comparison of the PCI, FCIQMC, and density matrix renormalization
group (DMRG) methods. The size of the PCI wave function grows modestly with the
number of unoccupied orbitals and its accuracy may be tuned to match that of
FCIQMC and DMRG.


title:
Dynamic Hierarchical Dirichlet Process for Abnormal Behaviour Detection
  in Video

abstract:
  This paper proposes a novel dynamic Hierarchical Dirichlet Process topic
model that considers the dependence between successive observations.
Conventional posterior inference algorithms for this kind of models require
processing of the whole data through several passes. It is computationally
intractable for massive or sequential data. We design the batch and online
inference algorithms, based on the Gibbs sampling, for the proposed model. It
allows to process sequential data, incrementally updating the model by a new
observation. The model is applied to abnormal behaviour detection in video
sequences. A new abnormality measure is proposed for decision making. The
proposed method is compared with the method based on the non- dynamic
Hierarchical Dirichlet Process, for which we also derive the online Gibbs
sampler and the abnormality measure. The results with synthetic and real data
show that the consideration of the dynamics in a topic model improves the
classification performance for abnormal behaviour detection.


title:
Amplification of Magnetic Fields in a Primordial HII Region and
  Supernova

abstract:
  Magnetic fields permeate the Universe on all scales and play a key role
during star formation. We study the evolution of magnetic fields around a
massive metal-free (Population III) star at $z \sim 15$ during the growth of
its HII region and subsequent supernova explosion by conducting three
cosmological magnetohydrodynamic simulations with radiation transport. Given
the theoretical uncertainty and weak observational constraints of magnetic
fields in the early universe, we initialize the simulations with identical
initial conditions only varying the seed field strength. We find that magnetic
fields grow as $\rho^{2/3}$ during the gravitational collapse preceding star
formation, as expected from ideal spherical collapse models. Massive Population
III stars can expel a majority of the gas from the host halo through radiative
feedback, and we find that the magnetic fields are not amplified above the
spherical collapse scaling relation during this phase. However, afterwards when
its supernova remnant can radiatively cool and fragment, the turbulent velocity
field in and around the shell causes the magnetic field to be significantly
amplified on average by $\sim$100 in the shell and up to 6 orders of magnitude
behind the reverse shock. Within the shell, field strengths are on the order of
a few nG at a number density of 1 cm$^{-3}$. We show that this growth is
primarily caused by small-scale dynamo action in the remnant. These
strengthened fields will propagate into the first generations of galaxies,
possibly affecting the nature of their star formation.


title: Carbon and oxygen isotopic ratios for nearby miras

abstract:
  C and O isotopic ratios are reported for a sample of 46 Mira and SRa-type
variable AGB stars. Vibration-rotation 1st and 2nd overtone CO lines in 1.5 to
2.5 $\mu$m spectra were measured to derive isotopic ratios for 12C/13C,
16O/17O, and 16O/18O. Comparisons with previous measurements for individual
stars and with various samples of evolved stars are discussed. Models for solar
composition AGB stars of different initial masses are used to interpret our
results. We find that the majority of the M stars had main sequence masses < 2
Msun and have not experienced sizable third dredge-up episodes. The progenitors
of the four S-type stars in our sample are slightly more massive. Of the 6 C
stars in the sample three have clear evidence relating their origin to the
occurrence of the third dredge-up. Comparisons with O-rich presolar grains from
AGB stars that lived before the formation of the solar system reveal variations
in the interstellar medium chemical composition. The present generation of
low-mass AGB stars show a large spread of 16O/17O ratios, similar to that of
group 1 presolar grains and in agreement with theoretical expectations for the
composition of mass 1.2 to 2 Msun stars after the 1st dredge up. On the
contrary, the 16O/18O ratios of present-day LPVs are definitely smaller than
those of group 1 grains. This occurrence is most probably a consequence of the
the decrease with time of the 16O/18O ratio in the interstellar medium due to
the chemical evolution of the Milky Way. One star in our sample has an O
composition similar to that of group 2 presolar grains originating in an AGB
star undergoing extramixing. This occurrence may indicate that the extramixing
process is hampered at high metallicity or, equivalently, favored at low
metallicity. Similar to O-rich grains no star in our sample shows evidence of
HBB, expected for massive AGB stars.


title: Classes of Weingarten Surfaces in S^2xR

abstract:
  In this work we study surfaces in radial conformally flat spaces. We
characterize surfaces of rotation with constant Gaussian and Extrinsic
curvature in these radial 3-spaces. We prove that all the spheres in the
conformal 3-space have constant Gaussian curvature $K=1$ if, and only if, the
conformal factor is special. In this special case we study geometric properties
of this ambient 3-space, and as an application we prove that it is isometric to
the space ${\mathbb{S}}^2\times {\mathbb{R}}$, so we consider it as the {\em
Radial Model} of ${\mathbb{S}}^2\times {\mathbb{R}}$. We obtain two classes of
Weingarten surfaces in the {\em Radial Model}, which satisfy
$\tilde{K}_E+\tilde{H}^2-\tilde{K}=0 $ and $2\tilde{K}_E-\tilde{K}=0 $, where
$\tilde{K}$ is the Gaussian curvature, $\tilde{H}$ is the mean curvature and
$\tilde{K}_E$ is the extrinsic curvature. Moreover, by using the relations
between the curvatures of the {\em Radial Model} and the curvatures with
respect to the euclidean metric ([CPS]), we prove that first class the
Weingarten surfaces in {\em Radial Model} corresponds, up to isometries, to the
minimal surfaces in $\mathbb{R}^3$, and second class corresponds to EDSGHW -
surfaces in Euclidean space $ \mathbb{R} ^ 3$(\cite{DC}). Consequently these
two classes of surfaces have a Weierstrass type representation depending on two
holomorphic functions.


title: Privacy Knowledge Modelling for Internet of Things: A Look Back

abstract:
  Internet of Things (IoT) and cloud computing together give us the ability to
sense, collect, process, and analyse data so we can use them to better
understand behaviours, habits, preferences and life patterns of users and lead
them to consume resources more efficiently. In such knowledge discovery
activities, privacy becomes a significant challenge due to the extremely
personal nature of the knowledge that can be derived from the data and the
potential risks involved. Therefore, understanding the privacy expectations and
preferences of stakeholders is an important task in the IoT domain. In this
paper, we review how privacy knowledge has been modelled and used in the past
in different domains. Our goal is not only to analyse, compare and consolidate
past research work but also to appreciate their findings and discuss their
applicability towards the IoT. Finally, we discuss major research challenges
and opportunities.


title:
Finite time blowup for Lagrangian modifications of the three-dimensional
  Euler equation

abstract:
  In the language of differential geometry, the incompressible inviscid Euler
equations can be written in vorticity-vector potential form as \begin{align*}
\partial_t \omega + {\mathcal L}_u \omega &= 0\\ u &= \delta \tilde \eta^{-1}
\Delta^{-1} \omega \end{align*} where $\omega$ is the vorticity $2$-form,
${\mathcal L}_u$ denotes the Lie derivative with respect to the velocity field
$u$, $\Delta$ is the Hodge Laplacian, $\delta$ is the codifferential (the
negative of the divergence operator), and $\tilde \eta^{-1}$ is the canonical
map from $2$-forms to $2$-vector fields induced by the Euclidean metric $\eta$.
In this paper we consider a generalisation of these Euler equations in three
spatial dimensions, in which the vector potential operator $\tilde \eta^{-1}
\Delta^{-1}$ is replaced by a more general operator $A$ of order $-2$; this
retains the Lagrangian structure of the Euler equations, as well as most of its
conservation laws and local existence theory. Despite this, we give three
different constructions of such an operator $A$ which admits smooth solutions
that blow up in finite time, including an example on ${\bf R}^3$ which is
self-adjoint and positive definite. This indicates a barrier to establishing
global regularity for the three-dimensional Euler equations, in that any such
method must use some property of those equations that is not shared by the
generalised Euler equations considered here.


title: Exactly Solvable Models for Symmetry-Enriched Topological Phases

abstract:
  We construct fixed-point wave functions and exactly solvable
commuting-projector Hamiltonians for a large class of bosonic symmetry-enriched
topological (SET) phases, based on the concept of equivalent classes of
symmetric local unitary transformations. We argue that for onsite unitary
symmetries, our construction realizes all SETs free of anomaly, as long as the
underlying topological order itself can be realized with a commuting-projector
Hamiltonian. We further extend the construction to anti-unitary symmetries
(e.g. time-reversal symmetry), mirror-reflection symmetries, and to anomalous
SETs on the surface of three-dimensional symmetry-protected topological phases.
Mathematically, our construction naturally leads to a generalization of group
extensions of unitary fusion categories to anti-unitary symmetries.


title: Space of dark states in Tavis-Cummings model

abstract:
  The dark states of a group of two-level atoms in the Tavis-Cummings resonator
with zero detuning are considered. In these states, atoms can not emit photons,
although they have non-zero energy. They are stable and can serve as a
controlled energy reservoir from which photons can be extracted by
differentiated effects on atoms, for example, their spatial separation. Dark
states are the simplest example of a subspace free of decoherence in the form
of a photon flight, and therefore are of interest for quantum computing. It is
proved that a) the dimension of the subspace of dark states of atoms is the
Catalan numbers, b) in the RWA approximation, any dark state is a linear
combination of tensor products of singlet-type states and the ground states of
individual atoms. For the exact model, in the case of the same force of
interaction of atoms with the field, the same decomposition is true, and only
singlets participate in the products and the dark states can neither emit a
photon nor absorb it. The proof is based on the method of quantization of the
amplitude of states of atomic ensembles, in which the roles of individual atoms
are interchangeable. In such an ensemble there is a possibility of
micro-causality: the trajectory of each quantum of amplitude can be uniquely
assigned.


title: A brief geometric derivation of some fundamental physics

abstract:
  Several fundamental results in physics are derived from the simple starting
point of two commuting orthogonal unit vectors. The combination of these unit
vectors leads to spherical harmonics and Schwinger's expression of the
second-quantized angular momentum states in terms of bosonic operators.
Commuting unit vectors can be turned into anticommuting ones by the restriction
to a single unit vector. This leads to Pauli spin matrices. By including
hyperbolic rotations, vectors can be given a finite norm and results from
special relativity and Dirac's equation are found. The assumption that the
change in four-momentum is due to the change in four-potential leads to the
electromagnetic field tensor and the Lorentz force. Mawell's equations are
obtained by viewing the four-potential as an harmonic oscillator driven by the
four-current. The Schr\"odinger equation is obtained from the nonrelativistic
limit of the four-momentum.


title: The 3x3 rooks graph is the unique smallest graph with lazy cop number 3

abstract:
  In the ordinary version of the pursuit-evasion game "cops and robbers", a
team of cops and a robber occupy vertices of a graph and alternately move along
the graph's edges, with perfect information about each other. If a cop lands on
the robber, the cops win; if the robber can evade the cops indefinitely, he
wins. In the variant "lazy cops and robbers", the cops may only choose one
member of their squad to make a move when it's their turn. The minimum number
of cops (respectively lazy cops) required to catch the robber is called the
"cop number" (resp. "lazy cop number") of G and is denoted $c(G)$ (resp.
$c_L(G)$). Previous work by Beveridge at al. has shown that the Petersen graph
is the unique graph on ten vertices with $c(G)=3$, and all graphs on nine or
fewer vertices have $c(G)\leq 2$. (This was a self-contained mathematical proof
of a result found by computational search by Baird and Bonato.) In this
article, we prove a similar result for lazy cops, namely that the 3x3 rooks
graph ($K_3\square K_3$) is the unique graph on nine vertices which requires
three lazy cops, and a graph on eight or fewer vertices requires at most two
lazy cops.


title: Quaternionic Aharonov-Bohm effect

abstract:
  A quaternionic analog of the Aharonov-Bohm effect is developed without the
usual anti-hermitian operators in quaternionic quantum mechanics (QQM). A
quaternionic phase links the solutions obtained to ordinary complex wave
functions, and new theoretical studies and experimental tests are possible for
them.


title: Effects of Reducing Scaffolding in an Undergraduate Electronics Lab

abstract:
  Design and scientific investigation are recognized as key components of
undergraduate physics laboratory curricula. In light of this, many successful
lab programs have been developed to train students to develop these abilities,
and students in these programs have been shown to exhibit a higher transfer
rate of scientific abilities to new situations. In this paper, I use data from
an electronics class for physics majors to investigate how giving students the
opportunity to design circuits --- by removing steps from traditional cookbook
lab guides --- affects the students' ability to determine the function of
circuits they haven't seen before. I compared post-lab quiz results from
students who were given explicit procedures to those of students who were given
incomplete procedures, and I found no statistically significant difference in
the results of the two groups. I explore possible explanations for the null
effect and recommend future research directions.


title: Curating Transient Population in Urban Dynamics System

abstract:
  For past several decades, research efforts in population modelling has proven
its efficacy in understanding the basic information about residential and
commercial areas, as well as for the purposes of planning, development and
improvement of the community as an eco-system. More or less, such efforts
assume static nature of population distribution, in turn limited by the current
ability to capture the dynamics of population change at a finer resolution of
space and time. Fast forward today, more and more people are becoming mobile,
traveling across borders impacting the nuts and bolts of our urban fabric.
Unfortunately, our current efforts are being surpassed by the need to capture
such transient population. It is becoming imperative to identify and define
them, as well as measure their dynamics and interconnectedness. In this work,
we intend to research urban population mobility patterns, gauge their transient
nature, and extend our knowledge of their visited locations. We plan to achieve
this by designing and developing novel methods and using VGI data that models
and characterizes transient population dynamics.


title: Reducing parametric backscattering by polarization rotation

abstract:
  When a laser passes through underdense plasmas, Raman and Brillouin
Backscattering can reflect a substantial portion of the incident laser energy.
This is a major loss mechanism, for example, in employing lasers in inertial
confinement fusion. However, by slow rotation of the incident linear
polarization, the overall reflectivity can be reduced significantly. Particle
in cell simulations show that, for parameters similar to those of indirect
drive fusion experiments, polarization rotation reduces the reflectivity by a
factor of $5$. A general, fluid-model based, analytical estimation for the
reflectivity reduction agrees with simulations. However, in identifying the
source of the backscatter reduction, it is difficult to disentangle the
rotating polarization from the frequency separation based approach used to
engineer the beam's polarization. Although the backscatter reduction arises
similarly to other approaches that employ frequency separation, in the case
here, the intensity remains constant in time.


title:
Asymptotic behavior of semistable L\'evy exponents and applications to
  fractal path properties

abstract:
  This paper proves sharp bounds on the tails of the L\'evy exponent of an
operator semistable law on $\mathbb R^d$. These bounds are then applied to
explicitly compute the Hausdorff and packing dimensions of the range, graph,
and other random sets describing the sample paths of the corresponding operator
semi-selfsimilar L\'evy processes. The proofs are elementary, using only the
properties of the L\'evy exponent, and certain index formulae.


title:
The Chemical Composition of Red Giant Branch Stars in the Galactic
  Globular Clusters NGC 6342 and NGC 6366

abstract:
  We present radial velocities and chemical abundances for red giant branch
stars in the Galactic bulge globular clusters NGC 6342 and NGC 6366. The
velocities and abundances are based on measurements of high resolution (R >
20,000) spectra obtained with the MMT-Hectochelle and WIYN-Hydra spectrographs.
We find that NGC 6342 has a heliocentric radial velocity of +112.5 km/s (sigma
= 8.6 km/s), NGC 6366 has a heliocentric radial velocity of -122.3 km/s (sigma
= 1.5 km/s), and that both clusters have nearly identical metallicities ([Fe/H]
~ -0.55). NGC 6366 shows evidence of a moderately extended O-Na
anti-correlation, but more data are needed for NGC 6342 to determine if this
cluster also exhibits the typical O-Na relation likely found in all other
Galactic globular clusters. The two clusters are distinguished from similar
metallicity field stars as having larger [Na/Fe] spreads and enhanced [La/Fe]
ratios, but we find that NGC 6342 and NGC 6366 display alpha and Fe-peak
element abundance patterns that are typical of other metal-rich ([Fe/H] > -1)
inner Galaxy clusters. However, the median [La/Fe] abundance may vary from
cluster-to-cluster.


title:
Finiteness theorems on hypersurfaces in partial differential-algebraic
  geometry

abstract:
  Hrushovski's generalization and application of [Jouanolou, "Hypersurfaces
solutions d'une \'equation de Pfaff analytique", Mathematische Annalen, 232
(3):239--245, 1978] is here refined and extended to the partial differential
setting with possibly nonconstant coefficient fields. In particular, it is
shown that if $X$ is a differential-algebraic variety over a partial
differential field F that is finitely generated over its constant field F_0,
then there exists a dominant differential-rational map from X to the constant
points of an algebraic variety V over F_0, such that all but finitely many
codimension one subvarieties of X over F arise as pull-backs of algebraic
subvarieties of V over F_0. As an application, it is shown that the algebraic
solutions to a first order algebraic differential equation over C(t) are of
bounded height, answering a question of Eremenko. Two expected model-theoretic
applications to DCF_{0,m} are also given: 1) Lascar rank and Morley rank agree
in dimension two, and 2) dimension one strongly minimal sets orthogonal to the
constants are \aleph_0-categorical. A detailed exposition of Hrushovski's
original (unpublished) theorem is included, influenced by [Ghys, "\`A propos
d'un th\'eor\`eme de J.-P. Jouanolou concernant les feuilles ferm\'ees des
feuilletages holomorphes", Rend. Circ. Mat. Palermo (2)}, 49(1):175--180, 2000.


title:
Diagnostics of Coronal Magnetic Fields Through the Hanle Effect in UV
  and IR Lines

abstract:
  The plasma thermodynamics in the solar upper atmosphere, particularly in the
corona, are dominated by the magnetic field, which controls the flow and
dissipation of energy. The relative lack of knowledge of the coronal vector
magnetic field is a major handicap for progress in coronal physics. This makes
the development of measurement methods of coronal magnetic fields a high
priority in solar physics. The Hanle effect in the UV and IR spectral lines is
a largely unexplored diagnostic. We use magnetohydrodynamic (MHD) simulations
to study the magnitude of the signal to be expected for typical coronal
magnetic fields for selected spectral lines in the UV and IR wavelength ranges,
namely the H I Ly-$\alpha$ and the He I 10830 {\AA} lines. We show that the
selected lines are useful for reliable diagnosis of coronal magnetic fields.
The results show that the combination of polarization measurements of spectral
lines with different sensitivities to the Hanle effect may be most appropriate
for deducing coronal magnetic properties from future observations.


title:
Measurement of the 2$\nu\beta\beta$ decay half-life of $^{150}$Nd and a
  search for 0$\nu\beta\beta$ decay processes with the full exposure from the
  NEMO-3 detector

abstract:
  We present results from a search for neutrinoless double-$\beta$
($0\nu\beta\beta$) decay using 36.6 g of the isotope $^{150}$Nd with data
corresponding to a live time of 5.25 y recorded with the NEMO-3 detector. We
construct a complete background model for this isotope, including a measurement
of the two-neutrino double-$\beta$ decay half-life of $T^{2\nu}_{1/2}=$[9.34
$\pm$ 0.22 (stat.) $^{+0.62}_{-0.60}$ (syst.)]$\times 10^{18}$ y for the ground
state transition, which represents the most precise result to date for this
isotope. We perform a multivariate analysis to search for \zeronu decays in
order to improve the sensitivity and, in the case of observation, disentangle
the possible underlying decay mechanisms. As no evidence for \zeronu decay is
observed, we derive lower limits on half-lives for several mechanisms involving
physics beyond the Standard Model. The observed lower limit, assuming light
Majorana neutrino exchange mediates the decay, is $T^{0\nu}_{1/2} >$ 2.0
$\times 10^{22}$ y at the 90% C.L., corresponding to an upper limit on the
effective neutrino mass of $\langle m_{\nu} \rangle$ $<$ 1.6 - 5.3 eV..


title:
Network-Efficient Distributed Word2vec Training System for Large
  Vocabularies

abstract:
  Word2vec is a popular family of algorithms for unsupervised training of dense
vector representations of words on large text corpuses. The resulting vectors
have been shown to capture semantic relationships among their corresponding
words, and have shown promise in reducing a number of natural language
processing (NLP) tasks to mathematical operations on these vectors. While
heretofore applications of word2vec have centered around vocabularies with a
few million words, wherein the vocabulary is the set of words for which vectors
are simultaneously trained, novel applications are emerging in areas outside of
NLP with vocabularies comprising several 100 million words. Existing word2vec
training systems are impractical for training such large vocabularies as they
either require that the vectors of all vocabulary words be stored in the memory
of a single server or suffer unacceptable training latency due to massive
network data transfer. In this paper, we present a novel distributed, parallel
training system that enables unprecedented practical training of vectors for
vocabularies with several 100 million words on a shared cluster of commodity
servers, using far less network traffic than the existing solutions. We
evaluate the proposed system on a benchmark dataset, showing that the quality
of vectors does not degrade relative to non-distributed training. Finally, for
several quarters, the system has been deployed for the purpose of matching
queries to ads in Gemini, the sponsored search advertising platform at Yahoo,
resulting in significant improvement of business metrics.


title: Phase diagram of matrix compressed sensing

abstract:
  In the problem of matrix compressed sensing we aim to recover a low-rank
matrix from few of its element-wise linear projections. In this contribution we
analyze the asymptotic performance of a Bayes-optimal inference procedure for a
model where the matrix to be recovered is a product of random matrices. The
results that we obtain using the replica method describe the state evolution of
the recently introduced P-BiG-AMP algorithm. We show the existence of different
types of phase transitions, their implications for the solvability of the
problem, and we compare the results of the theoretical analysis to the
performance reached by P-BiG-AMP. Remarkably the asymptotic replica equations
for matrix compressed sensing are the same as those for a related but formally
different problem of matrix factorization.


title: Spin susceptibility of Andreev bound states

abstract:
  We calcuate electronic spin susceptibility and spin-lattice relaxation rate
in singlet superconductor near a pairbreaking surface, or in a domain wall of
the order parameter. We directly link presence of high-density Andreev bound
states in the inhomogeneous region, combined with coherence factors, to
enhancement of the susceptibility above the normal state's value for certain
$\bf q$ vectors. Beside the dominant peak at ferromagnetic vector $q=0$, we
find significant enhancement of antiferromagnetic correlations at vectors
$q\lesssim 2 k_f$, with $\bf q$ $along$ the domain wall in $S$-wave
superconductor, and $across$ domain wall in $D$-wave (nodes along the wall).
These features are destroyed by applying moderate Zeeman field that splits the
zero-energy peak. We solve Bogoliubov-de Gennes equations in momentum space and
our results deviate from the lattice models investigated previously. Large
enhancement of the spin-lattice relaxation rate $T_1^{-1}$ at the domain wall
provides clear signature of the quasiparticle bound states, and is in good
agreement with recent experiment in organic superconductor
$\kappa$-(BEDT-TTF)$_2$Cu(NCS)$_2$.


title:
Sparse aperture masking at the VLT II. Detection limits for the eight
  debris disks stars $\beta$ Pic, AU Mic, 49 Cet, $\eta$ Tel, Fomalhaut, g Lup,
  HD181327 and HR8799

abstract:
  Context. The formation of planetary systems is a common, yet complex
mechanism. Numerous stars have been identified to possess a debris disk, a
proto-planetary disk or a planetary system. The understanding of such formation
process requires the study of debris disks. These targets are substantial and
particularly suitable for optical and infrared observations. Sparse Aperture
masking (SAM) is a high angular resolution technique strongly contributing to
probe the region from 30 to 200 mas around the stars. This area is usually
unreachable with classical imaging, and the technique also remains highly
competitive compared to vortex coronagraphy. Aims. We aim to study debris disks
with aperture masking to probe the close environment of the stars. Our goal is
either to find low mass companions, or to set detection limits. Methods. We
observed eight stars presenting debris disks ( $\beta$ Pictoris, AU
Microscopii, 49 Ceti, $\eta$ Telescopii, Fomalhaut, g Lupi, HD181327 and
HR8799) with SAM technique on the NaCo instrument at the VLT. Results. No close
companions were detected using closure phase information under 0.5 of
separation from the parent stars. We obtained magnitude detection limits that
we converted to Jupiter masses detection limits using theoretical isochrones
from evolutionary models. Conclusions. We derived upper mass limits on the
presence of companions in the area of few times the diffraction limit of the
telescope around each target star.


title:
Realistic $\mathrm{SU(3)_c \otimes SU(3)_L \otimes U(1)_X}$ model with a
  type II Dirac neutrino seesaw mechanism

abstract:
  Here we propose a realistic $\mathrm{SU(3)_c \otimes SU(3)_L \otimes U(1)_X}$
electroweak gauge model with enlarged Higgs sector. The scheme allows for the
natural implementation of a type II seesaw mechanism for Dirac neutrinos, while
charged lepton and quark masses are reproduced in a natural way thanks to the
presence of new scalars. The new $\mathrm{SU(3)_c \otimes SU(3)_L \otimes
U(1)_X}$ energy scale characterizing neutrino mass generation could be
accessible to the current LHC experiments.


title: Improving Beckner's bound via Hermite functions

abstract:
  We obtain an improvement of the Beckner's inequality $\| f\|^{2}_{2}
-\|f\|^{2}_{p} \leq (2-p) \| \nabla f\|_{2}^{2}$ valid for $p \in [1,2]$ and
the Gaussian measure. Our improvement is essential for the intermediate case $p
\in (1,2)$, and moreover, we find the natural extension of the inequality for
any real $p$.


title:
Symmetric and antisymmetric properties of solutions to kernel-based
  machine learning problems

abstract:
  A particularly interesting instance of supervised learning with kernels is
when each training example is associated with two objects, as in pairwise
classification (Brunner et al., 2012), and in supervised learning of preference
relations (Herbrich et al., 1998). In these cases, one may want to embed
additional prior knowledge into the optimization problem associated with the
training of the learning machine, modeled, respectively, by the symmetry of its
optimal solution with respect to an exchange of order between the two objects,
and by its antisymmetry. Extending the approach proposed in (Brunner et al.,
2012) (where the only symmetric case was considered), we show, focusing on
support vector binary classification, how such embedding is possible through
the choice of a suitable pairwise kernel, which takes as inputs the individual
feature vectors and also the group feature vectors associated with the two
objects. We also prove that the symmetry/antisymmetry constraints still hold
when considering the sequence of suboptimal solutions generated by one version
of the Sequential Minimal Optimization (SMO) algorithm, and we present
numerical results supporting the theoretical findings. We conclude discussing
extensions of the main results to support vector regression, to transductive
support vector machines, and to several kinds of graph kernels, including
diffusion kernels.


title:
The search for electroweak-scale right-handed neutrinos and mirror
  charged leptons through like-sign dilepton signals

abstract:
  The existence of tiny neutrino masses at a scale more than a million times
smaller than the lightest charged fermion mass, namely the electron, and their
mixings can not be explained within the framework of the exceptionally
successful Standard Model. There are four ideas that has been proposed to
explain the tiny neutrino masses. These include the see-saw mechanism with a
right handed neutrino at the GUT scale, and this is the most elegant mechanism.
The other mechanisms are radiatively generated neutrino masses, the neutrino
mass arising from a 2nd Higgs doublet having a tiny VEV and coupling only to
the neutrinos, and finally the mirror model or simply the EW-scale $\nu_R$
model. The mirror model has new quarks and leptons of opposite chirality at the
electroweak scale (for the same Standard Model gauge symmetry $SU(2)_W \times
U(1)_Y$) compared to what we have for the Standard Model. With suitable
modification of the Higgs sector, the EW-scale $\nu_R$ model satisfies the
electroweak precision test and also the constraints coming from the observed
125-GeV Higgs scalar. Since in this model, the mirror fermions are required to
be in the EW scale, these can be produced at the LHC giving final states with a
very low background from the SM. One such final state is the same sign
dileptons with large missing $p_T$ for the events. In this work, we explore the
constraint provided by the $8$ TeV data, and prospect of observing this signal
in the $13$ TeV runs at the LHC. Additional signals will be the presence of
displaced vertices depending on the smallness of the Yukawa couplings of the
mirror leptons with the ordinary leptons and the singlet Higgs present in the
model. Of particular importance to the EW-scale $\nu_R$ model is the production
of $\nu_R$ which will be a direct test of the seesaw mechanism at collider
energies.


title:
Analysis of two-orbital correlations in wavefunctions restricted to
  electron-pair states

abstract:
  Wavefunctions constructed from electron-pair states can accurately model
strong electron correlation effects and are promising approaches especially for
larger many-body systems. In this article, we analyze the nature and the type
of electron correlation effects that can be captured by wavefunctions
restricted to electron-pair states. We focus on the Antisymmetric Product of
1-reference orbital Geminal (AP1roG) method combined with an orbital
optimization protocol presented in [Phys. Rev. B, 89, 201106(R), 2014] whose
performance is assessed against electronic structures obtained form DMRG
reference data. Our numerical analysis covers model systems for strong
correlation: the one-dimensional Hubbard model with periodic boundary condition
as well as metallic and molecular hydrogen rings. Specifically, the accuracy of
AP1roG is benchmarked using the single-orbital entropy, the orbital-pair mutual
information as well as the eigenvalue spectrum of the one-orbital and
two-orbital reduced density matrices. Our study indicates that contributions
from singly occupied states become important in the strong correlation regime
which highlights the limitations of the AP1roG method. Furthermore, we examine
the effect of orbital rotations within the AP1roG model on correlations between
orbital pairs.


title: Mixed $f$-divergence for multiple pairs of measures

abstract:
  In this paper, the concept of the classical $f$-divergence for a pair of
measures is extended to the mixed $f$-divergence for multiple pairs of
measures. The mixed $f$-divergence provides a way to measure the difference
between multiple pairs of (probability) measures. Properties for the mixed
$f$-divergence are established, such as permutation invariance and symmetry in
distributions. An Alexandrov-Fenchel type inequality and an isoperimetric
inequality for the mixed $f$-divergence are proved.


title:
Horizon Instability of Extremal Kerr Black Holes: Nonaxisymmetric Modes
  and Enhanced Growth Rate

abstract:
  We show that the horizon instability of the extremal Kerr black hole is
associated with a singular branch point in the Green function at the
superradiant bound frequency. We study generic initial data supported away from
the horizon and find an enhanced growth rate due to nonaxisymmetric modes. The
growth is controlled by the conformal weight of each mode. We speculate on
connections to near-extremal black holes and holographic duality.


title:
Correlation-powered Information Engines and the Thermodynamics of
  Self-Correction

abstract:
  Information engines can use structured environments as a resource to generate
work by randomizing ordered inputs and leveraging the increased Shannon entropy
to transfer energy from a thermal reservoir to a work reservoir. We give a
broadly applicable expression for the work production of an information engine,
generally modeled as a memoryful channel that communicates inputs to outputs as
it interacts with an evolving environment. The expression establishes that an
information engine must have more than one memory state in order to leverage
input environment correlations. To emphasize this functioning, we designed an
information engine powered solely by temporal correlations and not by
statistical biases, as employed by previous engines. Key to this is the
engine's ability to synchronize---the engine automatically returns to a desired
dynamical phase when thrown into an unwanted, dissipative phase by corruptions
in the input---that is, by unanticipated environmental fluctuations. This
self-correcting mechanism is robust up to a critical level of corruption,
beyond which the system fails to act as an engine. We give explicit analytical
expressions for both work and critical corruption level and summarize engine
performance via a thermodynamic-function phase diagram over engine control
parameters. The results reveal a new thermodynamic mechanism based on
nonergodicity that underlies error correction as it operates to support
resilient engineered and biological systems.

categories: cond-mat.stat-mech cs.IT math.DS math.IT nlin.CD physics.bio-ph


title: Structural Protein-based Flexible Whispering Gallery Mode Resonators

abstract:
  Nature provides a set of solutions for photonic structures that are finely
tuned, organically diverse and optically efficient. Exquisite knowledge of
structure-property relationships in proteins aids in the design of materials
with desired properties for building devices with novel functionalities, which
are difficult to achieve or previously unattainable. Recent bio-inspired
photonic platforms made from proteinaceous materials lay the groundwork for
many functional device applications, such as electroluminescence in peptide
nucleic acids, multiphoton absorption in amyloid fibers and silk waveguides and
inverse opals. Here we report whispering-gallery-mode (WGM) microresonators
fabricated entirely from semi-crystalline structural proteins (i.e., squid ring
teeth, SRT, from Loligo vulgaris and its recombinant) with unconventional
thermo-optic response. We demonstrated waveguides, add-drop filters and
flexible resonators as first examples of energy-efficient, highly flexible,
biocompatible and biodegradable protein-based photonic devices. Optical
switching efficiency in these devices is over thousand times greater than the
values reported for Silica WGM resonators. This work opens the way for
designing energy efficient functional photonic devices using structure-
property relationships of proteins.


title:
Applications of the Fokker-Planck equation in circuit quantum
  electrodynamics

abstract:
  We study exact solutions of the steady state behaviour of several non-linear
open quantum systems which can be applied to the field of circuit quantum
electrodynamics. Using Fokker-Planck equations in the generalised
P-representation we investigate the analytical solutions of two fundamental
models. First, we solve for the steady-state response of a linear cavity that
is coupled to an approximate transmon qubit and use this solution to study both
the weak and strong driving regimes, using analytical expressions for the
moments of both cavity and transmon fields, along with the Husimi Q-function
for the transmon. Second, we revisit exact solutions of quantum Duffing
oscillator which is driven both coherently and parametrically while also
experiencing decoherence by the loss of single and pairs of photons. We use
this solution to discuss both stabilisation of Schroedinger cat states and the
generation of squeezed states in parametric amplifiers, in addition to studying
the Q-functions of the different phases of the quantum system. The field of
superconducting circuits, with its strong nonlinearities and couplings, has
provided access to a new parameter regime in which returning to these exact
quantum optics methods can provide valuable insights.


title:
Mutually avoiding paths in random media and largests eigenvalues of
  random matrices

abstract:
  Recently, it was shown that the probability distribution function (PDF) of
the free energy of a single continuum directed polymer (DP) in a random
potential, equivalently of the height of a growing interface described by the
Kardar-Parisi-Zhang (KPZ) equation, converges at large scale to the Tracy-Widom
distribution.The latter describes the fluctuations of the largest eigenvalue of
a random matrice, drawn from the Gaussian Unitary Ensemble (GUE), and the
result holds for a DP with fixed endpoints, i.e. for the KPZ equation with
droplet initial conditions. A more general conjecture can be put forward,
relating the free energies of $N>1$ non-crossing continuum DP in a random
potential, to the $N$-th largest eigenvalues of the GUE. Here, using replica
methods, we provide an important test of this conjecture by calculating exactly
the right tails of both PDF's and showing that they coincide for arbitrary $N$.


title:
Determining the full weight distribution of any irreducible cyclic code
  over any finite field of dimension two

abstract:
  In coding theory, a very interesting problem (but at the same time, a very
difficult one) is to determine the weight distribution of a given code. This
problem is even more interesting for cyclic codes, and this is so, mainly
because they possess a rich algebraic structure, which can be utilized in a
variety of ways. For example, in Engineering Telecommunications, this structure
is commonly employed to design very efficient coding and decoding algorithms.
In this note, we are going to use a characterization of all semiprimitive
two-weight irreducible cyclic codes over any finite field, recently presented
in [8], in order to determine the full weight distribution of any irreducible
cyclic code over any finite field of dimension two. In fact, the relevance of
our results is that by means of them we can actually directly determine the
full weight distribution of any irreducible cyclic code, of dimension one or
two, just by knowing its length.


title:
Uncovering Mass Segregation with Galaxy Analogues in Dark Matter
  Simulations

abstract:
  We investigate mass segregation in group and cluster environments by
identifying galaxy analogues in high-resolution dark matter simulations.
Subhalos identified by the AHF and ROCKSTAR halo finders have similar mass
functions, independent of resolution, but different radial distributions due to
significantly different subhalo hierarchies. We propose a simple way to
classify subhalos as galaxy analogues. The radial distributions of galaxy
analogues agree well at large halo-centric radii for both AHF and ROCKSTAR but
disagree near parent halo centres where the phase-space information used by
ROCKSTAR is essential.
  We see clear mass segregation at small radii (within $0.5\,r_{vir}$) with
average galaxy analogue mass decreasing with radius. Beyond the virial radius,
we find a mild trend where the average galaxy analogue mass increases with
radius. These mass segregation trends are strongest in small groups and
dominated by the segregation of low mass analogues. The lack of mass
segregation in massive galaxy analogues suggests that the observed trends are
driven by the complex accretion histories of the parent halos rather than
dynamical friction.


title:
Nine Channel Mid-Power Bipolar Pulse Generator Based on a Field
  Programmable Gate Array

abstract:
  Many channel arbitrary pulse sequence generation is required for the
electro-optic reconfiguration of optical waveguide networks in Lithium Niobate.
Here we describe a scalable solution to the requirement for mid-power bipolar
parallel outputs, based on pulse patterns generated by an externally clocked
field programmable gate array (FPGA). Positive and negative pulses can be
generated at repetition rates from up to 80~MHz with pulse width adjustable in
increments of 1.6~ns across nine independent outputs. Each channel can provide
1.5W of RF power and it can be synchronised with the operation of other
components in an optical network such as light sources and detectors through an
external clock with adjustable delay.


title: SelQA: A New Benchmark for Selection-based Question Answering

abstract:
  This paper presents a new selection-based question answering dataset, SelQA.
The dataset consists of questions generated through crowdsourcing and sentence
length answers that are drawn from the ten most prevalent topics in the English
Wikipedia. We introduce a corpus annotation scheme that enhances the generation
of large, diverse, and challenging datasets by explicitly aiming to reduce word
co-occurrences between the question and answers. Our annotation scheme is
composed of a series of crowdsourcing tasks with a view to more effectively
utilize crowdsourcing in the creation of question answering datasets in various
domains. Several systems are compared on the tasks of answer sentence selection
and answer triggering, providing strong baseline results for future work to
improve upon.


title: Towards Verified Artificial Intelligence

abstract:
  Verified artificial intelligence (AI) is the goal of designing AI-based
systems that that have strong, ideally provable, assurances of correctness with
respect to mathematically-specified requirements. This paper considers Verified
AI from a formal methods perspective. We describe five challenges for achieving
Verified AI, and five corresponding principles for addressing these challenges.


title: Directly Constraining Marginal Prices

abstract:
  The marginal price of electricity traditionally depends on the dual variables
associated with relevant optimization goals. Particularly, in the optimal power
flow realm, prices represent the cost of supplying an additional unit of power
at each bus; for the economic dispatch case, dual variables represent the cost
of supplying an additional unit of power to the whole system. Dual variables
are useful for many additional tasks, including the analysis of system
congestion and the determination of the cost of load adjustments. In this
letter, departing from conventional optimal power flow analysis, it is shown
how constraints on relevant dual variables affect the prices of electricity,
allowing for market settings and demand response programs that accept bids and
caps on individual prices.


title: Annulled van der Waals interaction and fast Rydberg quantum gates

abstract:
  A pair of neutral atoms separated by several microns and prepared in
identical s-states of large principal quantum number experience a van der Waals
interaction. If microwave fields are used to generate a superposition of
s-states with different principal quantum numbers, a null point may be found at
which a specific superposition state experiences no van der Waals interaction.
An application of this novel Rydberg state in a quantum controlled-Z gate is
proposed, which takes advantage of GHz rate transitions to nearby Rydberg
states. A gate operation time in the tens of nanoseconds is predicted.


title: Mayer-Vietoris squares in algebraic geometry

abstract:
  We consider various notions of Mayer--Vietoris squares in algebraic geometry.
We use these to generalize a number of gluing and pushout results of
Moret-Bailly, Ferrand--Raynaud, Joyet and Bhatt. An important intermediate step
is Gabber's rigidity theorem for henselian pairs, which our methods give a new
proof of.


title:
Stability of SIS Spreading Processes in Networks with Non-Markovian
  Transmission and Recovery

abstract:
  Although viral spreading processes taking place in networks are often
analyzed using Markovian models in which both the transmission and the recovery
times follow exponential distributions, empirical studies show that, in many
real scenarios, the distribution of these times are not necessarily
exponential. To overcome this limitation, we first introduce a generalized
susceptible-infected-susceptible (SIS) spreading model that allows transmission
and recovery times to follow phase-type distributions. In this context, we
derive a lower bound on the exponential decay rate towards the infection-free
equilibrium of the spreading model without relying on mean-field
approximations. Based on our results, we illustrate how the particular shape of
the transmission/recovery distribution influences the exponential rate of
convergence towards the equilibrium.


title:
Sea ice trends in climate models only accurate in runs with biased
  global warming

abstract:
  Observations indicate that the Arctic sea ice cover is rapidly retreating
while the Antarctic sea ice cover is steadily expanding. State-of-the-art
climate models, by contrast, typically simulate a moderate decrease in both the
Arctic and Antarctic sea ice covers. However, in each hemisphere there is a
small subset of model simulations that have sea ice trends similar to the
observations. Based on this, a number of recent studies have suggested that the
models are consistent with the observations in each hemisphere when simulated
internal climate variability is taken into account. Here we examine sea ice
changes during 1979-2013 in simulations from the most recent Coupled Model
Intercomparison Project (CMIP5) as well as the Community Earth System Model
Large Ensemble (CESM-LE), drawing on previous work that found a close
relationship in climate models between global-mean surface temperature and sea
ice extent. We find that all of the simulations with 1979-2013 Arctic sea ice
retreat as fast as observed have considerably more global warming than
observations during this time period. Using two separate methods to estimate
the sea ice retreat that would occur under the observed level of global warming
in each simulation in both ensembles, we find that simulated Arctic sea ice
retreat as fast as observed would occur less than 1% of the time. This implies
that the models are not consistent with the observations. In the Antarctic, we
find that simulated sea ice expansion as fast as observed typically corresponds
with too little global warming, although these results are more equivocal. We
show that because of this, the simulations do not capture the observed
asymmetry between Arctic and Antarctic sea ice trends. This suggests that the
models may be getting the right sea ice trends for the wrong reasons in both
polar regions.


title:
A Possible 55-day X-ray Period of the Ultraluminous Accreting Pulsar M82
  X-2

abstract:
  We report a possible detection of a 55-day X-ray modulation for the
ultraluminous accreting pulsar M82 X-2 from archival Chandra observations.
Because M82 X-2 is known to have a 2.5-day orbital period, if the 55-day period
is real, it will be the superorbital period of the system. We also investigated
variabilities of other three nearby ultraluminous X-ray sources in the central
region of M82 with the Chandra data and did not find any evidence of
periodicities. Furthermore, we re-examined the previously reported 62-day
periodicity near the central region of M82 by performing a systematic timing
study with all the archival Rossi X-Ray Timing Explorer and Swift data. Using
various dynamic timing analysis methods, we confirmed that the 62-day period is
not stable, suggesting that it is not the orbital period of M82 X-1 in
agreement with previous work.


title: Event Identification in Social Networks

abstract:
  Social networks enable users to freely communicate with each other and share
their recent news, ongoing activities or views about different topics. As a
result, they can be seen as a potentially viable source of information to
understand the current emerging topics/events. The ability to model emerging
topics is a substantial step to monitor and summarize the information
originating from social sources. Applying traditional methods for event
detection which are often proposed for processing large, formal and structured
documents, are less effective, due to the short length, noisiness and
informality of the social posts. Recent event detection techniques address
these challenges by exploiting the opportunities behind abundant information
available in social networks. This article provides an overview of the state of
the art in event detection from social networks.


title: Hubble Space Telescope Observations of Active Asteroid 324P/La Sagra

abstract:
  Hubble Space Telescope observations of active asteroid 324P/La Sagra near
perihelion show continued mass loss consistent with the sublimation of
near-surface ice. Isophotes of the coma measured from a vantage point below the
orbital plane are best matched by steady emission of particles having a nominal
size $a \sim$ 100 $\mu$m. The inferred rate of mass loss, $dM_d/dt \sim$0.2 kg
s$^{-1}$, can be supplied by sublimation of water ice in thermal equilibrium
with sunlight from an area as small as 930 m$^2$, corresponding to about 0.2\%
of the nucleus surface. Observations taken from a vantage point only
0.6\degr~from the orbital plane of 324P set a limit to the velocity of ejection
of dust in the direction perpendicular to the plane, $V_{\perp} <$ 1 m
s$^{-1}$. Short-term photometric variations of the near-nucleus region, if
related to rotation of the underlying nucleus, rule out periods $\le$ 3.8 hr
and suggest that rotation probably does not play a central role in driving the
observed mass loss. We estimate that, in the previous orbit, 324P lost about
4$\times$10$^7$ kg in dust particles, corresponding to 6$\times$10$^{-5}$ of
the mass of a 550 m spherical nucleus of assumed density $\rho$ = 1000 kg
m$^{-3}$. If continued, mass loss at this rate would limit the lifetime of 324P
to $\sim$1.6$\times$10$^4$ orbits (about 10$^5$ yr). To survive for the 100 Myr
to 400 Myr timescales corresponding, respectively, to dynamical and collisional
stability requires a duty cycle $2\times 10^{-4} \le f_d \le 8\times 10^{-4}$.
Unless its time in orbit is over-estimated by many orders of magnitude, 324P is
revealed as a briefly-active member of a vast population of otherwise dormant
ice-containing asteroids.


title: Betti Geometric Langlands

abstract:
  We introduce and survey a Betti form of the geometric Langlands conjecture,
parallel to the de Rham form developed by Beilinson-Drinfeld and
Arinkin-Gaitsgory, and the Dolbeault form of Donagi-Pantev, and inspired by the
work of Kapustin-Witten in supersymmetric gauge theory. The conjecture proposes
an automorphic category associated to a compact Riemann surface X and complex
reductive group G is equivalent to a spectral category associated to the
underlying topological surface S and Langlands dual group G^. The automorphic
category consists of suitable C-sheaves on the moduli stack Bun_G(X) of
G-bundles on X, while the spectral category consists of suitable O-modules on
the character stack Loc_G^(S) of G^-local systems on S. The conjecture is
compatible with and constrained by the natural symmetries of both sides coming
from modifications of bundles and local systems. On the one hand, cuspidal
Hecke eigensheaves in the de Rham and Betti sense are expected to coincide, so
that one can view the Betti conjecture as offering a different "integration
measure" on the same fundamental objects. On the other hand, the Betti spectral
categories are more explicit than their de Rham counterparts and one might hope
the conjecture is less challenging. The Betti program also enjoys symmetries
coming from topological field theory: it is expected to extend to an
equivalence of four-dimensional topological field theories, and in particular,
the conjecture for closed surfaces is expected to reduce to the case of the
thrice-punctured sphere. Finally, we also present ramified, quantum and
integral variants of the conjecture, and highlight connections to other topics,
including representation theory of real reductive groups and quantum groups.


title:
Behavior of Quasinormal Modes and high dimension RN-AdS Black Hole phase
  transition

abstract:
  In this work we use the quasinormal frequencies of a massless scalar
perturbation to probe the phase transition of the high dimension charged-AdS
black hole. The signature of the critical behavior of this black hole solution
is detected in the isobaric as well as in isothermal process. This paper is a
natural generalization of \cite{base} to higher dimensional spacetime. More
precisely our study shows a clear signal for any dimension $d$ in the isobaric
process. As to the isothermal case, we find out that this signature can be
affected by other parameters like the pressure and the horizon radius. We
conclude that the quasinormal modes can be an efficient tool to investigate the
first order phase transition, but fail to disclose the signature of the second
order phase transition.


title: Generalizations of Joints Problem

abstract:
  We generalize the joints problem to sets of varieties and prove almost sharp
bound on the number of joints. As a special case, given a set of $N$ $2$-planes
in $\mathbb{R}^6$, the number of points at which three $2$-planes intersect and
span $\mathbb{R}^6$ is at most $CN^{3/2+\epsilon}$. We also get almost sharp
bound on the number of joints with multiplicities. The main tools are
polynomial partitioning and induction on dimension.


title: Quenching of charge and spin degrees of freedom in condensed matter

abstract:
  Electrons in condensed matter have internal degrees of freedom, such as
charge, spin and orbital, leading to various forms of ordered states through
phase transitions. However, in individual materials, a charge/spin/orbital
ordered state of the lowest temperature is normally uniquely determined in
terms of the lowest-energy state, i.e., the ground state. Here, we summarize
recent results showing that under rapid cooling, this principle does not
necessarily hold, and thus, the cooling rate is a control parameter of the
lowest-temperature state beyond the framework of the thermo-equilibrium phase
diagram. Although the cooling rate utilized in low-temperature experiments is
typically 2*10^-3 - 4*10^-1 K/s, the use of optical/electronic pulses
facilitate rapid cooling, such as 10^2-10^3 K/s. Such an unconventionally high
cooling rate allows some systems to kinetically avoid a first-order phase
transition, resulting in a quenched charge/spin state that differs from the
ground state. We also demonstrate that quenched states can be exploited as a
non-volatile state variable when designing phase-change memory functions. The
present findings suggest that rapid cooling is useful for exploring and
controlling the metastable electronic/magnetic state that is potentially hidden
behind the ground state.


title: Introduction to Einstein-Maxwell equations and the Rainich conditions

abstract:
  The first results of Einstein-Maxwell equations established by Raincih in
1925 are therefore called the Raincih conditions. Later the result was
rediscovered by Misner and Wheeler in 1957 and made the basis of their
geometrodynamics. The present survey will consider didactically the curvature
of spacetime attributed to an electromagnetic field with conceptual and
calculational details.


title: Probabilistic Human Mobility Model in Indoor Environment

abstract:
  Understanding human mobility is important for the development of intelligent
mobile service robots as it can provide prior knowledge and predictions of
human distribution for robot-assisted activities. In this paper, we propose a
probabilistic method to model human motion behaviors which is determined by
both internal and external factors in an indoor environment. While the internal
factors are represented by the individual preferences, aims and interests, the
external factors are indicated by the stimulation of the environment. We model
the randomness of human macro-level movement, e.g., the probability of visiting
a specific place and staying time, under the Bayesian framework, considering
the influence of both internal and external variables. We use two case studies
in a shopping mall and in a college student dorm building to show the
effectiveness of our proposed probabilistic human mobility model. Real
surveillance camera data are used to validate the proposed model together with
survey data in the case study of student dorm.


title:
Dynamics of D-branes I. The non-Abelian Dirac-Born-Infeld action, its
  first variation, and the equations of motion for D-branes --- with remarks on
  the non-Abelian Chern-Simons/Wess-Zumino term

abstract:
  In earlier works, D(1) (arXiv:0709.1515 [math.AG]), D(11.1) (arXiv:1406.0929
[math.DG]), D(11.2) (arXiv:1412.0771 [hep-th]), and D(11.3.1) (arXiv:1508.02347
[math.DG]), we have explained why a D-brane in string theory, when treated as a
fundamental dynamical object, can be described by a map $\varphi$ from an
Azumaya/matrix manifold $X^{Az}$ (cf. D-brane world-volume) with a fundamental
module with a connection $(E,\nabla)$ (cf. Chan-Paton bundle) to the target
space-time $Y$. In this sequel, we construct a non-Abelian Dirac-Born-Infeld
action functional $S_{DBI}^{(\Phi, g, B)}(\varphi,\nabla)$ for such pairs
$(\varphi,\nabla)$. We next develop a technical tool needed to study variations
of this action and apply it to derive the first variation $\delta
S_{DBI}^{(\Phi,g,B)}/\delta(\varphi,\nabla)$ of $S_{DBI}^{(\Phi,g,B)}$ with
respect to $(\varphi,\nabla)$. The equations of motion that govern the dynamics
of D-branes then follow. A complete action for a D-brane world-volume must
include also the Chern-Simons/Wess-Zumino term
$S_{CS/WZ}^{(C)}(\varphi,\nabla)$ that governs how the D-brane world-volume
couples with the Ramond-Ramond fields $C$ on $Y$. In the current notes, a
version $S^{(C,B)}_{CS/WZ}(\varphi,\nabla)$ of non-Abelian
Chern-Simons/Wess-Zumino action functional for $(\varphi,\nabla)$ that follows
the same guide with which we construct $S^{(\Phi,g,B)}_{DBI}(\varphi,\nabla)$
is constructed for lower-dimensional D-branes (i.e. D(-1)-, D0-, D1-,
D2-branes). Its first variation $\delta
S^{(C,B)}_{CS/WZ}(\varphi,\nabla)/\delta(\varphi,\nabla)$ is derived and its
contribution to the equations of motion for $(\varphi, \nabla)$ follows. The
current notes lay down a foundation toward the dynamics of D-branes along the
line of this D-project.


title: Spectral radius and Hamiltonian properties of graphs, II

abstract:
  In this paper, we first present spectral conditions for the existence of
$C_{n-1}$ in graphs (2-connected graphs) of order $n$, which are motivated by a
conjecture of Erd\H{o}s. Then we prove spectral conditions for the existence of
Hamilton cycles in balanced bipartite graphs. This result presents a spectral
analog of Moon-Moser's theorem on Hamilton cycles in balanced bipartite graphs,
and extends a previous theorem due to Li and the second author for $n$
sufficiently large. We conclude this paper with two problems on tight spectral
conditions for the existence of long cycles of given lengths.


title:
A Learning Algorithm for Relational Logistic Regression: Preliminary
  Results

abstract:
  Relational logistic regression (RLR) is a representation of conditional
probability in terms of weighted formulae for modelling multi-relational data.
In this paper, we develop a learning algorithm for RLR models. Learning an RLR
model from data consists of two steps: 1- learning the set of formulae to be
used in the model (a.k.a. structure learning) and learning the weight of each
formula (a.k.a. parameter learning). For structure learning, we deploy Schmidt
and Murphy's hierarchical assumption: first we learn a model with simple
formulae, then more complex formulae are added iteratively only if all their
sub-formulae have proven effective in previous learned models. For parameter
learning, we convert the problem into a non-relational learning problem and use
an off-the-shelf logistic regression learning algorithm from Weka, an
open-source machine learning tool, to learn the weights. We also indicate how
hidden features about the individuals can be incorporated into RLR to boost the
learning performance. We compare our learning algorithm to other structure and
parameter learning algorithms in the literature, and compare the performance of
RLR models to standard logistic regression and RDN-Boost on a modified version
of the MovieLens data-set.


title: The extremal function for cycles of length $\ell$ mod $k$

abstract:
  Burr and Erd\H{o}s conjectured that for each $k,\ell \in \mathbb Z^+$ such
that $k \mathbb Z + \ell$ contains even integers, there exists $c_k(\ell)$ such
that any graph of average degree at least $c_k(\ell)$ contains a cycle of
length $\ell$ mod $k$. This conjecture was proved by Bollob\'{a}s, and many
successive improvements of upper bounds on $c_k(\ell)$ appear in the
literature. In this short note, for $1 \leq \ell \leq k$, we show that
$c_k(\ell)$ is proportional to the largest average degree of a $C_{\ell}$-free
graph on $k$ vertices, which determines $c_k(\ell)$ up to an absolute constant.
In particular, using known results on Tur\'{a}n numbers for even cycles, we
obtain $c_k(\ell) = O(\ell k^{2/\ell})$ for all even $\ell$, which is tight for
$\ell \in \{4,6,10\}$. Since the complete bipartite graph $K_{\ell - 1,n - \ell
+ 1}$ has no cycle of length $2\ell$ mod $k$, it also shows $c_k(\ell) =
\Theta(\ell)$ for $\ell = \Omega(\log k)$.


title:
A weak finite element method for elliptic problems in one space
  dimension

abstract:
  We present a weak finite element method for elliptic problems in one space
dimension. Our analysis shows that this method has more advantages than the
known weak Galerkin method proposed for multi-dimensional problems, for
example, it has higher accuracy and the derived discrete equations can be
solved locally, element by element. We derive the optimal error estimates in
the discrete $H^1$-norm, the $L_2$-norm and $L_\infty$-norm, respectively.
Moreover, some superconvergence results are also given. Finally, numerical
examples are provided to illustrate our theoretical analysis.


title:
Static Ranking of Scholarly Papers using Article-Level Eigenfactor
  (ALEF)

abstract:
  Microsoft Research hosted the 2016 WSDM Cup Challenge based on the Microsoft
Academic Graph. The goal was to provide static rankings for the articles that
make up the graph, with the rankings to be evaluated against those of human
judges. While the Microsoft Academic Graph provided metadata about many aspects
of each scholarly document, we focused more narrowly on citation data and used
this contest as an opportunity to test the Article Level Eigenfactor (ALEF), a
novel citation-based ranking algorithm, and evaluate its performance against
competing algorithms that drew upon multiple facets of the data from a large,
real world dataset (122M papers and 757M citations). Our final submission to
this contest was scored at 0.676, earning second place.


title: Semiparametric two-component mixture models under L-moments constraints

abstract:
  We propose a structure of a semiparametric two-component mixture model when
one component is parametric and the other is defined through L-moments
conditions. Estimation of a two-component mixture model with an unknown
component is very difficult when no particular assumption is made on the
structure of the unknown component. A previous work was proposed to incorporate
a prior linear information concerning the distribution function of the unknown
component such as moment constraints. We propose here to incorporate a prior
linear information about the quantile function of the unknown component
instead. This information is translated by L-moments constraints. L-moments
hold better information about the tail of the distribution and are considered
as good alternatives for moments especially for heavy tailed distributions
since they can be defined as soon as the distribution has finite expectation.
The new semiparametric mixture model is estimated using $\varphi-$divergences
which permit to build feasible algorithms. Asymptotic properties of the
resulting estimators are studied and proved under standard assumptions.
Simulations on data generated by several mixtures models demonstrate the
viability and the interest of our novel approach and the gain from using
L-moment constraints in comparison to the use of moments constraints.


title:
E-Embargoes: Discouraging the Deployment of Traffic Manipulating Boxes
  With Economic Incentives

abstract:
  An increasing number of systems have been proposed or deployed to the transit
core of the Internet with the goal of observing and manipulating traffic in
flight, systems we term Traffic Manipulating Boxes. Examples of these include:
decoy routing systems, surveillance infrastructure like the NSA's alleged
QUANTUM project, and traffic shaping middleboxes. In this work, we examine a
new approach that a routing capable adversary might take to resisting these
systems: the use of economic pressure to incentivize ISPs to remove them.
Rather than directly attacking the availability of these systems, our attack
inflicts economic losses, in the form of reduced transit revenue, on ISPs that
deploy them, while at the same time incentivizing ISPs that do not.
  We alter and expand upon previous routing around decoys attack of Schuchard
et al., by adjusting the priority given to avoiding TMBs. This reduces or
eliminates the key costs faced by routing capable adversary while maintaining
the effectiveness of the attack. Additionally, we show that since the flow of
traffic on the Internet is directly related to the flow of cash between ISPs, a
routing capable adversary is actually a powerful economic adversary. Our
findings show that by preferentially using routes which are free of TMBs, some
routing capable adversaries can inflict in excess of a billion dollars in
annual revenue losses.


title:
Revisiting the constraints on annihilating dark matter by radio
  observational data of M31

abstract:
  Recent gamma-ray observations and radio observations put strong constraints
on the parameters of dark matter annihilation. In this article, we derive new
constraints for six standard model annihilation channels by using the recent
radio data of M31 galaxy. The new constraints are generally tighter than the
constraints obtained from 6 years of Fermi Large Area Telescope gamma-ray
observations of the Milky Way dwarf spheroidal satellite galaxies. The
conservative lower limits of dark matter mass annihilating via $b\bar{b}$,
$\mu^+\mu^-$ and $\tau^+\tau^-$ channels are 90 GeV, 90 GeV and 80 GeV
respectively with the canonical thermal relic cross section and the Burkert
profile being the dark matter density profile. Hence, our results do not favor
the most popular models of the dark matter interpretation of the Milky Way GeV
gamma-ray excess.


title: A Local Density-Based Approach for Local Outlier Detection

abstract:
  This paper presents a simple but effective density-based outlier detection
approach with the local kernel density estimation (KDE). A Relative
Density-based Outlier Score (RDOS) is introduced to measure the local
outlierness of objects, in which the density distribution at the location of an
object is estimated with a local KDE method based on extended nearest neighbors
of the object. Instead of using only $k$ nearest neighbors, we further consider
reverse nearest neighbors and shared nearest neighbors of an object for density
distribution estimation. Some theoretical properties of the proposed RDOS
including its expected value and false alarm probability are derived. A
comprehensive experimental study on both synthetic and real-life data sets
demonstrates that our approach is more effective than state-of-the-art outlier
detection methods.


title:
A new approach to the connection problem for local solutions to the
  general Heun equation

abstract:
  We present new solution of the the connection problem for local solutions to
the general Heun equation. Our approach is based on the symmetric form of the
Heun's differential equation \cite{Fiziev14,Fiziev16} with four different
regular singular points $z_{1,2,3,4}$. The four special regular points in the
complex plane: $Z_{123},Z_{234},Z_{341},Z_{412}$ are the centers of the
circles, defined by the different triplets $\{z_k,z_l,z_m\}$ with corresponding
different indexes and play fundamental role, since the coefficients of the
connection matrix can be expressed using the values of local solutions of the
general Heun's equation at these points. A special case when all coefficients
can be calculated using only one of the points $Z_{klm}$ is also considered.


title: Approximation of points in the plane by generic lattice orbits

abstract:
  We give upper and lower bounds for Diophantine exponents measuring how well a
point in the plane can be approximated by points in the orbit of a lattice
$\Gamma<\mathrm{SL}_2(\mathbb{R})$ acting linearly on $\mathbb{R}^2$. Our
method gives bounds that are uniform for almost all orbits.


title:
A Class of Diffusion Algorithms with Logarithmic Cost over Adaptive
  Sparse Volterra Network

abstract:
  In this Letter, we present a novel class of diffusion algorithms that can be
used to estimate the coefficients of sparse Volterra network (SVN). The
development of the algorithms is based on the logarithmic cost and l0-norm
constraint. Simulations for Gaussian and impulsive scenarios are conducted to
demonstrate the superior performance of the proposed algorithms as compared
with the existing algorithms.


title:
High Angular Momentum Halo Gas: a Feedback and Code-Independent
  Prediction of LCDM

abstract:
  We investigate angular momentum acquisition in Milky Way-sized galaxies by
comparing five high resolution zoom-in simulations, each implementing identical
cosmological initial conditions, but utilizing different hydrodynamic codes:
Enzo, Art, Ramses, Arepo, and Gizmo-PSPH. Each code implements a distinct set
of feedback and star formation prescriptions. We find that while many galaxy
and halo properties vary between the different codes (and feedback
prescriptions), there is qualitative agreement on the process of angular
momentum acquisition in the galaxy's halo. In all simulations, cold filamentary
gas accretion to the halo results in ~4 times more specific angular momentum in
cold halo gas ($\lambda_{cold} \gtrsim 0.1$) than in the dark matter halo. At
z>1, this inflow takes the form of inspiraling cold streams that are
co-directional in the halo of the galaxy and are fueled, aligned, and
kinematically connected to filamentary gas infall along the cosmic web. Due to
the qualitative agreement among disparate simulations, we conclude that the
buildup of high angular momentum halo gas and the presence of these inspiraling
cold streams are robust predictions of Lambda Cold Dark Matter galaxy
formation, though the detailed morphology of these streams is significantly
less certain. A growing body of observational evidence suggests that this
process is borne out in the real universe.


title:
Effect of dark matter halo on global spiral modes in a collisionless
  galactic disc

abstract:
  Low surface brightness (LSB) galaxies are dominated by dark matter halo from
the innermost radii; hence they are ideal candidates to investigate the
influence of dark matter on different dynamical aspects of spiral galaxies.
Here, we study the effect of dark matter halo on grand-design, m = 2, spiral
modes in a galactic disk, treated as a collisionless system, by carrying out a
global modal analysis within the WKB approximation. First, we study a
superthin, LSB galaxy UGC 7321 and show that it does not support discrete
global spiral modes when modeled as a disk-alone system or as a disk plus dark
matter system. Even a moderate increase in the stellar central surface density
does not yield any global spiral modes. This naturally explains the observed
lack of strong large-scale spiral structure in LSBs. An earlier work (Ghosh,
Saini & Jog, 2016) where the galactic disk was treated as a fluid system for
simplicity had shown that the dominant halo could not arrest global modes. We
found that this difference arises due to the different dispersion relation used
in the two cases and which plays a crucial role in the search for global spiral
modes. Thus the correct treatment of stars as a collisionless system as done
here results in the suppression of global spiral modes, in agreement with the
observations. We performed a similar modal analysis for the Galaxy, and found
that the dark matter halo has a negligible effect on large-scale spiral
structure.