title: Photometry of some neglected bright cataclysmic variables and candidates

abstract:
  As part of an effort to better characterize bright cataclysmic variables
(CVs) which have received little attention in the past light curves of four
confirmed systems (CZ Aql, BO Cet, V380 Oph and EF Tuc) and one candidate (Lib
3) are analyzed. For none of these stars time resolved photometry has been
published previously. While no variability was found in the case of Lib 3,
which thus cannot be confirmed as a CV, the light curves of all other targets
are dominated by strong flickering. Modulations on hourly time scales
superimposed on the flickering can probably be related to orbital variations in
BO Cet and V380 Oph, but not in CZ Aql and EF Tuc. Variations on the time scale
of 10 minutes in CZ Aql, while not yet constituting convincing evidence,
together with previous suspicions of a magnetically channeled accretion flow
may point at an intermediate polar nature of this star. Some properties of the
flickering are quantified in an effort to enlarge the data base for future
comparative flickering studies in CVs and to refine the classification of the
target stars.


title: Community Detection in Complex Networks using Link Prediction

abstract:
  Community detection and link prediction are both of great significance in
network analysis, which provide very valuable insights into topological
structures of the network from different perspectives. In this paper, we
propose a novel community detection algorithm with inclusion of link
prediction, motivated by the question whether link prediction can be devoted to
improving the accuracy of community partition. For link prediction, we propose
two novel indices to compute the similarity between each pair of nodes, one of
which aims to add missing links, and the other tries to remove spurious edges.
Extensive experiments are conducted on benchmark data sets, and the results of
our proposed algorithm are compared with two classes of baseline. In
conclusion, our proposed algorithm is competitive, revealing that link
prediction does improve the precision of community detection.


title: Stationary time-vertex signal processing

abstract:
  This paper considers regression tasks involving high-dimensional multivariate
processes whose structure is dependent on some {known} graph topology. We put
forth a new definition of time-vertex wide-sense stationarity, or joint
stationarity for short, that goes beyond product graphs. Joint stationarity
helps by reducing the estimation variance and recovery complexity. In
particular, for any jointly stationary process (a) one reliably learns the
covariance structure from as little as a single realization of the process, and
(b) solves MMSE recovery problems, such as interpolation and denoising, in
computational time nearly linear on the number of edges and timesteps.
Experiments with three datasets suggest that joint stationarity can yield
accuracy improvements in the recovery of high-dimensional processes evolving
over a graph, even when the latter is only approximately known, or the process
is not strictly stationary.


title: On the restricted partition function II

abstract:
  Let $\mathbf a=(a_1,\ldots,a_r)$ be a vector of positive integers. In
continuation of a previous paper we present other formulas for the restricted
partition function $p_{\mathbf a}(n): = $ the number of integer solutions
$(x_1,\dots,x_r)$ to $\sum_{j=1}^r a_jx_j=n$ with $x_1\geq 0, \ldots, x_r\geq
0$.


title:
High harmonic generation in Landau-quantized graphene subjected to a
  strong electromagnetic radiation

abstract:
  We study nonlinear optical response of Landau quantized graphene to an
intense electromagnetic wave. In particular, we consider high harmonic
generation process. It is shown that one can achieve efficient generation of
high harmonics with strong radiation fields -- when the work of the wave
electric field on the magnetic length is larger than pump photon energy. At
that high harmonics generation process takes place for a wide range of the pump
wave frequencies and intensities even for significant broadening of Landau
levels because of impurities in graphene.


title:
Dual-Pivot Quicksort: Optimality, Analysis and Zeros of Associated
  Lattice Paths

abstract:
  We present an average case analysis of a variant of dual-pivot quicksort. We
show that the used algorithmic partitioning strategy is optimal, i.e., it
minimizes the expected number of key comparisons. For the analysis, we
calculate the expected number of comparisons exactly as well as asymptotically,
in particular, we provide exact expressions for the linear, logarithmic, and
constant terms.
  An essential step is the analysis of zeros of lattice paths in a certain
probability model. Along the way a combinatorial identity is proven.


title:
A study on the evolution of a community population by cumulative and
  fractional calculus approaches

abstract:
  Nowadays, in our globalized world,the local and intercountry movements of
population have been increased. This situation makes it important for host
countries to do right predictions for the future population of their native
people as well as immigrant people. The knowledge of the attained number of
accumulated population is necessary for future planning, concerning to
education,health, job, housing, safety requirements, etc. In this work, for
updating historically well known formulas of population dynamics of a community
are revisited in the framework of compound growth and fractional calculus to
get more realistic relations. Within this context, for a time t, the population
evolution of a society which owns two different components is calculated.
Concomitant relations have been developed to provide a comparison between the
native population and the immigrant population that come into existence where
at each time interval a colonial population is joined. Eventually at time t,
the case where the native population becomes equal to immigrant population is
discussed. Moreover, the differential equation of a probability function for
the equilibrium state of accumulative population is obtained. It is seen that
the equilibrium solution can be written as a series in terms of Bernoulli
numbers. In the calculation of population dynamics, Mittag- Leffler(M-L)
function replaces the exponential function.


title: Surrogate-Assisted Partial Order-based Evolutionary Optimisation

abstract:
  In this paper, we propose a novel approach (SAPEO) to support the survival
selection process in multi-objective evolutionary algorithms with surrogate
models - it dynamically chooses individuals to evaluate exactly based on the
model uncertainty and the distinctness of the population. We introduce variants
that differ in terms of the risk they allow when doing survival selection.
Here, the anytime performance of different SAPEO variants is evaluated in
conjunction with an SMS-EMOA using the BBOB bi-objective benchmark. We compare
the obtained results with the performance of the regular SMS-EMOA, as well as
another surrogate-assisted approach. The results open up general questions
about the applicability and required conditions for surrogate-assisted
multi-objective evolutionary algorithms to be tackled in the future.


title: Causal Compression

abstract:
  We propose a new method of discovering causal relationships in temporal data
based on the notion of causal compression. To this end, we adopt the Pearlian
graph setting and the directed information as an information theoretic tool for
quantifying causality. We introduce chain rule for directed information and use
it to motivate causal sparsity. We show two applications of the proposed
method: causal time series segmentation which selects time points capturing the
incoming and outgoing causal flow between time points belonging to different
signals, and causal bipartite graph recovery. We prove that modelling of
causality in the adopted set-up only requires estimating the copula density of
the data distribution and thus does not depend on its marginals. We evaluate
the method on time resolved gene expression data.


title:
Electronic and optical properties of two-dimensional InSe from a
  DFT-parameterized tight-binding model

abstract:
  We present a tight-binding (TB) model and $\mathbf{k\cdot p}$ theory for
electrons in monolayer and few-layer InSe. The model is constructed from a
basis of all $s$ and $p$ valence orbitals on both indium and selenium atoms,
with tight-binding parameters obtained from fitting to independently computed
density functional theory (DFT) band structures for mono- and bilayer InSe. For
the valence and conduction band edges of few-layer InSe, which appear to be in
the vicinity of the $\Gamma$ point, we calculate the absorption coefficient for
the principal optical transitions as a function of the number of layers, $N$.
We find a strong dependence on $N$ of the principal optical transition
energies, selection rules, and optical oscillation strengths, in agreement with
recent observations \cite{Bandurin2016}. Also, we find that the conduction band
electrons are relatively light ($m \propto 0.14-0.18 m_e$), in contrast to an
almost flat, and slightly inverted, dispersion of valence band holes near the
$\Gamma$-point, which is found for up to $N \propto 6$.


title:
An Experimental Comparison of Coded Modulation Strategies for 100 Gbit/s
  Transceivers

abstract:
  Coded modulation is a key technique to increase the spectral efficiency of
coherent optical communication systems. Two popular strategies for coded
modulation are turbo trellis-coded modulation (TTCM) and bit-interleaved coded
modulation (BICM) based on low-density parity-check (LDPC) codes. Although BICM
LDPC is suboptimal, its simplicity makes it very popular in practice. In this
work, we compare the performance of TTCM and BICM LDPC using
information-theoretic measures. Our information-theoretic results show that for
the same overhead and modulation format only a very small penalty (less than
0.1 dB) is to be expected when an ideal BICM LDPC scheme is used. However, the
results obtained for the coded modulation schemes implemented in this paper
show that the TTCM outperforms BICM LDPC by a larger margin. For a 1000 km
transmission at 100 Gbit/s, the observed gain was 0.4 dB.


title:
Uniform rectifiability from Carleson measure estimates and
  $\varepsilon$-approximability of bounded harmonic functions

abstract:
  Let $\Omega\subset\mathbb R^{n+1}$, $n\geq1$, be a corkscrew domain with
Ahlfors-David regular boundary. In this paper we prove that $\partial\Omega$ is
uniformly $n$-rectifiable if every bounded harmonic function on $\Omega$ is
$\varepsilon$-approximable or if every bounded harmonic function on $\Omega$
satisfies a suitable square-function Carleson measure estimate. In particular,
this applies to the case when $\Omega=\mathbb R^{n+1}\setminus E$ and $E$ is
Ahlfors-David regular. Our results solve a conjecture posed by Hofmann,
Martell, and Mayboroda in a recent work where they proved the converse
statements. Here we also obtain two additional criteria for uniform
rectifiability. One is given in terms of the so-called "$S<N$" estimates, and
another in terms of a suitable corona decomposition involving harmonic measure.


title: Decomposition complexity with respect to coarse properties

abstract:
  We formalize the concept of a family of metric spaces satisfying a coarse
property uniformly and we generalize finite decomposition complexity of Erik
Guentner, Romain Tessera, and Guoliang Yu. Of particular interest are results
determining sufficient conditions for a metric space to satisfy Property A of
Guoliang Yu.


title: A Seamless Multilevel Ensemble Transform Particle Filter

abstract:
  This paper presents a seamless algorithm for the application of the
multilevel Monte Carlo (MLMC) method to the ensemble transform particle filter
(ETPF). The algorithm uses a combination of optimal coupling transformations
between coarse and fine ensembles in difference estimators within a multilevel
framework, to minimise estimator variance. It differs from that of Gregory et
al. (2016) in that strong coupling between the coarse and fine ensembles is
seamlessly maintained during all stages of the assimilation algorithm, instead
of using independent transformations to equal weights followed by recoupling
with an assignment problem. This modification is found to lead to an increased
rate in variance decay between coarse and fine ensembles with level in the
hierarchy, a key component of MLMC. This offers the potential for greater
computational cost reductions. This is shown, alongside evidence of asymptotic
consistency, in numerical examples.


title:
The growth of polynomials orthogonal on the unit circle with respect to
  a weight w that satisfies $w$,$1/w \in L^\infty(\mathbb{T})$

abstract:
  We consider the weight w: 1<w<T on the unit circle and prove that the
corresponding orthonormal polynomials can grow.


title:
The interaction of seasonality and low-frequencies in a stochastic
  Arctic sea ice model

abstract:
  The stochastic Arctic sea ice model described as a single periodic
non-autonomous stochastic ordinary differential equation (ODE) is useful in
explaining the seasonal variability of Arctic sea ice. However, to be nearer to
realistic approximations we consider the inclusion of long-term forcing
implying the effect of slowly-varying ocean or atmospheric low-frequencies. In
this research, we rely on the equivalent Fokker-Planck equation instead of the
stochastic ODE owing to the advantages of the Fokker-Planck equation in dealing
with higher moments calculations. We include simple long-term forcing into the
Fokker-Planck equation and then seek approximate stochastic solutions. The
formalism based on the Fokker-Planck equation with a singular perturbation
method is flexible with regard to accommodating further complexity that arises
due to the inclusion of long-term forcing. These solutions are then applied to
the stochastic Arctic sea ice model with long-term forcing. Strong seasonality
in the Arctic sea ice model combined with long-term forcing, changes the
seasonal variability depending on the phase of the long-term forcing. The
change includes the shift of mean and the increase or decrease of variance and
skewness. Stochastic realisations show that the change of the statistical
moments due to long-term forcing is realised by unusual fluctuations
particularly concentrated at a specific time of a year.


abstract:
  Given a semisimple complex linear algebraic group $G$ and a lower ideal $I$
in positive roots of $G$, three objects arise: the ideal arrangement
$\mathcal{A}_I$, the regular nilpotent Hessenberg variety $\mbox{Hess}(N,I)$,
and the regular semisimple Hessenberg variety $\mbox{Hess}(S,I)$. We show that
a certain graded ring derived from the logarithmic derivation module of
$\mathcal{A}_I$ is isomorphic to $H^*(\mbox{Hess}(N,I))$ and
$H^*(\mbox{Hess}(S,I))^W$, the invariants in $H^*(\mbox{Hess}(S,I))$ under an
action of the Weyl group $W$ of $G$. This isomorphism is shown for general Lie
type, and generalizes Borel's celebrated theorem showing that the coinvariant
algebra of $W$ is isomorphic to the cohomology ring of the flag variety $G/B$.
  This surprising connection between Hessenberg varieties and hyperplane
arrangements enables us to produce a number of interesting consequences. For
instance, the surjectivity of the restriction map $H^*(G/B)\to
H^*(\mbox{Hess}(N,I))$ announced by Dale Peterson and an affirmative answer to
a conjecture of Sommers-Tymoczko are immediate consequences. We also give an
explicit ring presentation of $H^*(\mbox{Hess}(N,I))$ in types $B$, $C$, and
$G$. Such a presentation was already known in type $A$ or when
$\mbox{Hess}(N,I)$ is the Peterson variety. Moreover, we find the volume
polynomial of $\mbox{Hess}(N,I)$ and see that the hard Lefschetz property and
the Hodge-Riemann relations hold for $\mbox{Hess}(N,I)$, despite the fact that
it is a singular variety in general.


title:
When is Noisy State Information at the Encoder as Useless as No
  Information or as Good as Noise-Free State?

abstract:
  For any binary-input channel with perfect state information at the decoder,
if the mutual information between the noisy state observation at the encoder
and the true channel state is below a positive threshold determined solely by
the state distribution, then the capacity is the same as that with no encoder
side information. A complementary phenomenon is revealed for the generalized
probing capacity. Extensions beyond binary-input channels are developed.


title:
Application of Case-Based Teaching and Learning in Compiler Design
  Course

abstract:
  Compiler design is a course that discusses ideas used in construction of
programming language compilers. Students learn how a program written in high
level programming language and designed for humans understanding is
systematically converted into low level assembly language understood by
machines. We propose and implement a Case-based and Project-based Learning
environment for teaching important Compiler design concepts (CPLC) to B.Tech
third year students of a Delhi University (India) college. A case is a text
that describes a real-life situation providing information but not solution.
Previous research shows that case-based teaching helps students to apply the
principles discussed in the class for solving complex practical problems. We
divide one main project into sub-projects to give to students in order to
enhance their practical experience of designing a compiler. To measure the
effectiveness of case-based discussions, students complete a survey on their
perceptions of benefits of case-based learning. The survey is analyzed using
frequency distribution and chi square test of association. The results of the
survey show that case-based teaching of compiler concepts does enhance students
skills of learning, critical thinking, engagement, communication skills and
team work.


title:
Weak Measurement and Two-State-Vector Formalism: Deficit of Momentum
  Transfer in Scattering Processes

abstract:
  The notions of weak measurement, weak value, and two-state-vector formalism
provide a new quantum-theoretical frame for extracting additional information
from a system in the limit of small disturbances to its state. Here, we provide
an application to the case of two-body scattering with one body weakly
interacting with an environment. The direct connection to real scattering
experiments is pointed out by making contact with the field of impulsive
incoherent neutron scattering from molecules and condensed systems. In
particular, we predict a new quantum effect in neutron-atom collisions, namely
an observable momentum transfer deficit; or equivalently, a reduction of
effective mass below that of the free scattering atom. Two corroborative
experimental findings are shortly presented. Implications for current and
further experiments are mentioned. An interpretation of this effect and the
associated experimental results within conventional theory is currently
unavailable.


title:
Crystallography of deformation twinning in hexagonal close-packed
  metals. Revisiting the case of the (56 deg, a) contraction twins in magnesium

abstract:
  Contraction twinning in magnesium alloys leads to new grains that are
misoriented from the parent grain by a rotation of 56 deg around the a-axis.
The classical theory of deformation twinning does not precise the atomic
displacements and does not explain why contractions twinning is less frequent
than extension twinning. The paper proposes a new model in the continuity of
our previous works on martensitic transformations and extension twinning. A
continuous angular distortion matrix that transforms the initial hcp crystal
into a final hcp crystal is determined such that the atoms move as hard spheres
and reach the final positions expected by the orientation relationship. The
calculations prove that the distortion is not a simple shear when it is
considered in its continuity. The (01-11) twin plane is untilted and restored,
but it is not fully invariant because some interatomic distances in this plane
evolve during the distortion process; the unit volume also increases up to 5%
before coming back to its initial value when the twinning distortion is
complete. Then, the distortion takes the form a simple shear on the twin plane
with a shear direction along the direction [18,-5,-5] and a shear amplitude of
0.358. It is the first time that this twinning mode is reported. Experiments
are proposed to validate or infirm the new model.


title: Detecting Affordances by Visuomotor Simulation

abstract:
  The term "affordance" denotes the behavioral meaning of objects. We propose a
cognitive architecture for the detection of affordances in the visual modality.
This model is based on the internal simulation of movement sequences. For each
movement step, the resulting sensory state is predicted by a forward model,
which in turn triggers the generation of a new (simulated) motor command by an
inverse model. Thus, a series of mental images in the sensory and in the motor
domain is evoked. Starting from a real sensory state, a large number of such
sequences is simulated in parallel. Final affordance detection is based on the
generated motor commands. We apply this model to a real-world mobile robot
which is faced with obstacle arrangements some of which are passable (corridor)
and some of which are not (dead ends). The robot's task is to detect the right
affordance ("pass-through-able" or "non-pass-through-able"). The required
internal models are acquired in a hierarchical training process. Afterwards,
the robotic agent is able to distinguish reliably between corridors and dead
ends. This real-world result enhances the validity of the proposed mental
simulation approach. In addition, we compare several key factors in the
simulation process regarding performance and efficiency.


title: Four-Fermion Theories with Exact Chiral Symmetry in Three Dimensions

abstract:
  We investigate a class of four-fermion theories which includes well-known
models like the Gross-Neveu model and the Thirring model. In three spacetime
dimensions, they are used to model interesting solid state systems like high
temperature superconductors and graphene. Additionally, they serve as toy
models to study chiral symmetry breaking (CSB).
  For any number of fermion flavours the Gross-Neveu model has a broken and a
symmetric phase, while the existence of a broken phase in the Thirring model
depends on the number of flavours. The critical number of fermion flavours
beyond which there exists no CSB is still subject of ongoing discussions. Using
SLAC fermions we simulate the Thirring model with exact chiral symmetry. To
obtain a chiral condensate one can introduce a symmetry-breaking mass term and
carefully study the limits of infinite lattice and zero-mass. So far, we did
not see CSB within this approach for the Thirring model with 2 or more
(reducible) flavours.
  The talk presents alternative approaches to investigate these findings. We
employ certain Fierz identities to map the Thirring model into equivalent
four-fermion models, for which the chiral condensate does not seem to vanish.
In the new formulations based on reshuffled degrees of freedom we find a sign
problem (which is not present in the original formulation). For this reason we
developed an algorithm similar to fermion bags, which may solve this problem.
As a further approach, we embed the multi-flavour Thirring model in a larger
class of four-fermion theories to study the chiral symmetry and its breaking in
a wider context.


title:
The low-frequency dielectric response of charged oblate spheroidal
  particles immersed in an electrolyte

abstract:
  We study the low-frequency polarization response of a surface-charged oblate
spheroidal particle immersed in an electrolyte solution. Because the charged
spheroid attracts counter-ions which form the electric double layer around the
particle, using usual boundary conditions at the interface between the particle
and electrolyte can be quite complicated and challenging. Hence, we generalize
Fixman's boundary conditions, originally derived for spherical particles, to
the case of the charged oblate spheroid. Given two different counter-ion
distributions in the thin electric double layer limit, we obtain analytic
expressions for the polarization coefficients to the first non-trivial order in
frequency. We find that the polarization response normal to the symmetry axis
depends on the total amount of charge carried by the oblate spheroid while that
parallel to the symmetry axis is suppressed when there is less charge on the
edge of the spheroid. We further study the overall dielectric response for a
dilute suspension of charged spheroids. We find that the dielectric enhancement
at low frequency, which is driven by the presence of a large $\zeta$-potential
(surface charge), is suppressed by high ion concentrations in the electrolyte
and depends on the size of the suspended particles. In addition, spheroids with
higher aspect ratios will also lead to a stronger dielectric enhancement due to
the combination of the electric double layer and textural effects. The
characteristic frequency associated with the dielectric enhancement scales
inversely with the square of the particle size, the major radius of the
spheroid, and it has a weak dependence on the shape of spheroids.


title:
Joint Antenna Selection and Spatial Switching for Energy Efficient MIMO
  SWIPT System

abstract:
  In this paper, we investigate joint antenna selection and spatial switching
(SS) for quality-of-service (QoS)-constrained energy efficiency (EE)
optimization in a multiple-input multiple-output (MIMO) simultaneous wireless
information and power transfer (SWIPT) system. A practical linear power model
taking into account the entire transmit-receive chain is accordingly utilized.
The corresponding fractional-combinatorial and non-convex EE problem, involving
joint optimization of eigen-channel assignment, power allocation, and active
receive antenna set selection, subject to satisfying minimum sum-rate and power
transfer constraints, is extremely difficult to solve directly. In order to
tackle this, we separate the eigen-channel assignment and power allocation
procedure with the antenna selection functionality. In particular, we first
tackle the EE maximization problem under fixed receive antenna set using
Dinkelbach-based convex programming, iterative joint eigen-channel assignment
and power allocation, and low-complexity multi-objective optimization
(MOO)-based approach. On the other hand, the number of active receive antennas
induces a trade-off in the achievable sum-rate and power transfer versus the
transmit-independent power consumption. We provide a fundamental study of the
achievable EE with antenna selection and accordingly develop dynamic optimal
exhaustive search and Frobenius-norm-based schemes. Simulation results confirm
the theoretical findings and demonstrate that the proposed resource allocation
algorithms can efficiently approach the optimal EE.


title: Elliptic curves and continued fractions

abstract:
  It is proved that the rank of an elliptic curve is one less the arithmetic
complexity of the corresponding non-commutative torus. As an illustration, we
consider a family of elliptic curves with complex multiplication.


title: Percolation of disordered jammed sphere packings

abstract:
  We determine the site and bond percolation thresholds for a system of
disordered jammed sphere packings in the maximally random jammed state,
generated by the Torquato-Jiao algorithm. For the site threshold, which gives
the fraction of conducting vs. non-conducting spheres necessary for
percolation, we find $p_c = 0.3116(3)$, consistent with the 1979 value of
Powell $0.310(5)$ and identical within errors to the threshold for the
simple-cubic lattice, 0.311608, which shares the same average coordination
number of 6. In terms of the volume fraction $\varphi$, the threshold
corresponds to a critical value $\varphi_c = 0.199$. For the bond threshold,
which apparently was not measured before, we find $p_c = 0.2424(3)$. To find
these thresholds, we considered two shape-dependent universal ratios involving
the size of the largest cluster, fluctuations in that size, and the second
moment of the size distribution; we confirmed the ratios' universality by also
studying the simple-cubic lattice with a similar cubic boundary. The results
are applicable to many problems including conductivity in random mixtures,
glass formation, and drug loading in pharmaceutical tablets.


title: Search for a continuum limit of the PMS phase

abstract:
  Previous studies of a simple four-fermion model with staggered fermions in 3D
have shown the existence of an exotic quantum critical point, where one may be
able to define a continuum limit of the Paramagnetic Strong Phase (or the PMS
phase). We believe the existence of the critical point suggests a new mechanism
for generating fermion masses. In this work we begin the search for this
quantum critical point in 4D by extending the 3D model to 4D. Unlike in 3D, now
we do find evidence for an intermediate spontaneously broken phase (FM phase)
and are able compute the phase boundaries accurately. In terms of the bare
coupling, the width of the intermediate region appears to be quite small.


title:
Well-posedness of the Laplacian on manifolds with boundary and bounded
  geometry

abstract:
  Let $M$ be a Riemannian manifold with a smooth boundary. The main question we
address in this article is: "When is the Laplace-Beltrami operator
$\Delta\colon H^{k+1}(M)\cap H^1_0(M) \to H^{k-1}(M)$, $k\in \mathbb{N}_0$,
invertible?" We consider also the case of mixed boundary conditions. The study
of this main question leads us to the class of manifolds with boundary and
bounded geometry introduced by Schick (Math. Nach. 2001). We begin with some
needed results on the geometry of manifolds with boundary and bounded geometry.
Let $\partial_D M \subset \partial M$ be an open and closed subset of the
boundary of $M$. We say that $(M, \partial_D M)$ has \emph{finite width} if, by
definition, $M$ is a manifold with boundary and bounded geometry such that the
distance $d(x, \partial_D M)$ from a point $x \in M$ to $\partial_D M \subset
\partial M$ is bounded uniformly in $x$ (and hence, in particular, $\partial_D
M$ intersects all connected components of $M$). For manifolds $(M, \partial_D
M)$ with finite width, we prove a Poincar\'e inequality for functions vanishing
on $\partial_D M$, thus generalizing an important result of Sakurai (Osaka J.
Math, 2017). The Poincar\'e inequality then leads, as in the classical case to
results on the spectrum of $\Delta$ with domain given by mixed boundary
conditions, in particular, $\Delta$ is invertible for manifolds $(M, \partial_D
M)$ with finite width. The bounded geometry assumption then allows us to prove
the well-posedness of the Poisson problem with mixed boundary conditions in
higher Sobolev spaces $H^s(M)$, $s \ge 0$.


title:
A study of the radiative transition $\pi \pi \to \pi \gamma^{*}$ with
  lattice QCD

abstract:
  Lattice QCD calculations of radiative transitions between hadrons have in the
past been limited to processes of hadrons stable under the strong interaction.
Recently developed methods for $1\to2$ transition matrix elements in a finite
volume now enable the determination of radiative decay rates of strongly
unstable particles. Our lattice QCD study focuses on the process $\pi \pi \to
\pi \gamma^{*}$, where the $\rho$ meson is present as an enhancement in the
cross-section. We use $2+1$ flavors of clover fermions at a pion mass of
approximately $320$ MeV and a lattice size of approximately $3.6$ fm. The
required $2$-point and $3$-point correlation functions are constructed from a
set of forward, sequential and stochastic light quark propagators. In addition
to determining the $\rho$ meson resonance parameters via the L\"uscher method,
the scattering phase shift is used in conjunction with the $1\to2$ transition
matrix element formalism of Brice\~no, Hansen and Walker-Loud to compute the
$\pi\pi\to\pi\gamma^{*}$ amplitude at several values of the momentum transfer
and $\pi\pi$ invariant mass.


title:
How much a galaxy knows about its large-scale environment?: An
  information theoretic perspective

abstract:
  The small-scale environment characterized by the local density is known to
play a crucial role in deciding the galaxy properties but the role of
large-scale environment on galaxy formation and evolution still remain a less
clear issue. We propose an information theoretic framework to investigate the
influence of large-scale environment on galaxy properties and apply it to the
data from the Galaxy Zoo project which provides the visual morphological
classifications of $\sim 1$ million galaxies from the Sloan Digital Sky Survey.
We find a non-zero mutual information between morphology and environment which
decreases with increasing length scales but persists throughout the entire
length scales probed. We estimate the conditional mutual information and the
interaction information between morphology and environment by conditioning the
environment on different length scales and find a synergic interaction between
them which operates upto at least a length scales of $ \sim 30 \, h^{-1}\, {\rm
Mpc}$. Our analysis indicates that these interactions largely arise due to the
mutual information shared between the environments on different length scales.


title:
Dictionary Integration using 3D Morphable Face Models for Pose-invariant
  Collaborative-representation-based Classification

abstract:
  The paper presents a dictionary integration algorithm using 3D morphable face
models (3DMM) for pose-invariant collaborative-representation-based face
classification. To this end, we first fit a 3DMM to the 2D face images of a
dictionary to reconstruct the 3D shape and texture of each image. The 3D faces
are used to render a number of virtual 2D face images with arbitrary pose
variations to augment the training data, by merging the original and rendered
virtual samples to create an extended dictionary. Second, to reduce the
information redundancy of the extended dictionary and improve the sparsity of
reconstruction coefficient vectors using collaborative-representation-based
classification (CRC), we exploit an on-line elimination scheme to optimise the
extended dictionary by identifying the most representative training samples for
a given query. The final goal is to perform pose-invariant face classification
using the proposed dictionary integration method and the on-line pruning
strategy under the CRC framework. Experimental results obtained for a set of
well-known face datasets demonstrate the merits of the proposed method,
especially its robustness to pose variations.


title:
Linear non-equilibrium thermodynamics of human voluntary behavior: a
  canonical-dissipative Fokker-Planck equation approach involving potentials
  beyond the harmonic oscillator case

abstract:
  A novel experimental paradigm and a novel modelling approach are presented to
investigate oscillatory human motor performance by means of a key concept from
condensed matter physics, namely, thermodynamic state variables. To this end,
in the novel experimental paradigm participants performed pendulum swinging
movements at self-selected oscillation frequencies in contrast to earlier
studies in which pacing signals were used. Moreover, in the novel modelling
approach, a canonical-dissipative limit cycle oscillator model was used with a
conservative part that accounts for nonharmonic oscillator components in
contrast to earlier studies in which only harmonic components were considered.
Consistent with the Landau theory of magnetic phase transitions, we found that
the oscillator model free energy decayed when participants performed
oscillations further and further away from the Hopf bifurcation point of the
canonical-dissipative limit cycle oscillator.


title: Basmajian-type inequalities for maximal representations

abstract:
  For suitable metrics on the locally symmetric space associated to a maximal
representation, we prove inequalities between the length of the boundary and
the lengths of orthogeodesics that generalize the classical Basmajian's
identity from Teichmueller theory. Any equality characterizes diagonal
embeddings.


title:
Structured illumination microscopy with unknown patterns and a
  statistical prior

abstract:
  Structured illumination microscopy (SIM) improves resolution by
down-modulating high-frequency information of an object to fit within the
passband of the optical system. Generally, the reconstruction process requires
prior knowledge of the illumination patterns, which implies a well-calibrated
and aberration-free system. Here, we propose a new \textit{algorithmic
self-calibration} strategy for SIM that does not need to know the exact
patterns {\it a priori}, but only their covariance. The algorithm, termed
PE-SIMS, includes a Pattern-Estimation (PE) step requiring the uniformity of
the sum of the illumination patterns and a SIM reconstruction procedure using a
Statistical prior (SIMS). Additionally, we perform a pixel reassignment process
(SIMS-PR) to enhance the reconstruction quality. We achieve 2$\times$ better
resolution than a conventional widefield microscope, while remaining
insensitive to aberration-induced pattern distortion and robust against
parameter tuning.


title:
Efficient variants of the CMRH method for solving a sequence of
  multi-shifted non-Hermitian linear systems simultaneously

abstract:
  Multi-shifted linear systems with non-Hermitian coefficient matrices arise in
numerical solutions of time-dependent partial/fractional differential equations
(PDEs/FDEs), in control theory, PageRank problems, and other research fields.
We derive efficient variants of the restarted Changing Minimal Residual method
based on the cost-effective Hessenberg procedure (CMRH) for this problem class.
Then, we introduce a flexible variant of the algorithm that allows to use
variable preconditioning at each iteration to further accelerate the
convergence of shifted CMRH. We analyse the performance of the new class of
methods in the numerical solution of PDEs and FDEs, also against other
multi-shifted Krylov subspace methods.


title: Petroleum Refinery Multi-Antenna Propagation Measurements

abstract:
  This paper presents the results of the first multi- antenna propagation
measurement campaign to be conducted at an operating petroleum refining
facility. The measurement equipment transmits pseudo-random noise test signals
from two antennas at a 2.47 GHz carrier with a signal bandwidth of
approximately 25 MHz. The measurement data is analyzed to extract path loss
exponent, shadowing distribution, fading distribution, coherence bandwidth and
antenna correlation. The results reveal an environment where large scale
attenuation is relatively mild, fading is severe and good performance is
expected from both antenna and frequency diversity.


title: Matchings in $k$-partite $k$-uniform Hypergraphs

abstract:
  For $k\ge 3$ and $\epsilon>0$, let $H$ be a $k$-partite $k$-graph with parts
$V_1,\dots, V_k$ each of size $n$, where $n$ is sufficiently large. Assume that
for each $i\in [k]$, every $(k-1)$-set in $\prod_{j\in [k]\setminus \{i\}} V_i$
lies in at least $a_i$ edges, and $a_1\ge a_2\ge \cdots \ge a_k$. We show that
if $a_1, a_2\ge \epsilon n$, then $H$ contains a matching of size $\min\{n-1,
\sum_{i\in [k]}a_i\}$. In particular, $H$ contains a matching of size $n-1$ if
each crossing $(k-1)$-set lies in at least $\lceil n/k \rceil$ edges, or each
crossing $(k-1)$-set lies in at least $\lfloor n/k \rfloor$ edges and $n\equiv
1\bmod k$. This special case answers a question of R\"odl and Ruci\'nski and
was independently obtained by Lu, Wang, and Yu.
  The proof of Lu, Wang, and Yu closely follows the approach of Han [Combin.
Probab. Comput. 24 (2015), 723--732] by using the absorbing method and
considering an extremal case. In contrast, our result is more general and its
proof is thus more involved: it uses a more complex absorbing method and deals
with two extremal cases.


title:
Opportunistic Advertisement Scheduling in Live Social Media: A Multiple
  Stopping Time POMDP Approach

abstract:
  Live online social broadcasting services like YouTube Live and Twitch have
steadily gained popularity due to improved bandwidth, ease of generating
content and the ability to earn revenue on the generated content. In contrast
to traditional cable television, revenue in online services is generated solely
through advertisements, and depends on the number of clicks generated. Channel
owners aim to opportunistically schedule advertisements so as to generate
maximum revenue. This paper considers the problem of optimal scheduling of
advertisements in live online social media. The problem is formulated as a
multiple stopping problem and is addressed in a partially observed Markov
decision process (POMDP) framework. Structural results are provided on the
optimal advertisement scheduling policy. By exploiting the structure of the
optimal policy, best linear thresholds are computed using stochastic
approximation. The proposed model and framework are validated on real datasets,
and the following observations are made: (i) The policy obtained by the
multiple stopping problem can be used to detect changes in ground truth from
online search data (ii) Numerical results show a significant improvement in the
expected revenue by opportunistically scheduling the advertisements. The
revenue can be improved by $20-30\%$ in comparison to currently employed
periodic scheduling.


title: Cubic interactions of Maxwell-like higher spins

abstract:
  We study the cubic vertices for Maxwell-like higher-spins in flat and (A)dS
background spaces of any dimension. Reducibility of their free spectra implies
that a single cubic vertex involving any three fields subsumes a number of
couplings among different particles of various spins. The resulting vertices do
not involve traces of the fields and in this sense are simpler than their
Fronsdal counterparts. We propose an extension of both the free theory and of
its cubic deformation to a more general class of partially reducible systems,
that one can obtain from the original theory upon imposing trace constraints of
various orders. The key to our results is a version of the Noether procedure
allowing to systematically account for the deformations of the transversality
conditions to be imposed on the gauge parameters at the free level.


title: Open charm-bottom scalar tetraquarks and their strong decays

abstract:
  The mass and meson-current coupling of the diquark-antidiquark states with
the quantum numbers $J^{P}=0^{+}$ and quark contents $Z_{q}=[cq][\bar {b} \bar
q ]$ and $Z_{s}=[cs][\bar {b} \bar s]$ are calculated using two-point QCD sum
rule approach. In calculations the quark, gluon and mixing condensates up to
eight dimensions are taken into account. The parameters of the scalar
tetraquarks extracted from this analysis are employed to explore the strong
vertices $Z_q B_c \pi $, $Z_q B_c \eta $ and $Z_s B_c \eta $ and compute the
couplings $g_{Z_qB_c \pi }$, $g_{Z_qB_c \eta }$ and $g_{Z_sB_c \eta }$. The
strong couplings are obtained within the soft-meson approximation of QCD
light-cone sum rule method: they form, alongside with other parameters, the
basis for evaluating the widths of $Z_q \to B_c \pi$, $% Z_q \to B_c \eta$ and
$Z_s \to B_c \eta$ decays. Obtained in this work results for the mass of the
tetraquarks $Z_{q}$ and $Z_{s}$ are compared with available predictions
presented in the literature.


title:
Towards a theory of cortical columns: From spiking neurons to
  interacting neural populations of finite size

abstract:
  Neural population equations such as neural mass or field models are widely
used to study brain activity on a large scale. However, the relation of these
models to the properties of single neurons is unclear. Here we derive an
equation for several interacting populations at the mesoscopic scale starting
from a microscopic model of randomly connected generalized integrate-and-fire
neuron models. Each population consists of 50 -- 2000 neurons of the same type
but different populations account for different neuron types. The stochastic
population equations that we find reveal how spike-history effects in
single-neuron dynamics such as refractoriness and adaptation interact with
finite-size fluctuations on the population level. Efficient integration of the
stochastic mesoscopic equations reproduces the statistical behavior of the
population activities obtained from microscopic simulations of a full spiking
neural network model. The theory describes nonlinear emergent dynamics like
finite-size-induced stochastic transitions in multistable networks and
synchronization in balanced networks of excitatory and inhibitory neurons. The
mesoscopic equations are employed to rapidly simulate a model of a local
cortical microcircuit consisting of eight neuron types. Our theory establishes
a general framework for modeling finite-size neural population dynamics based
on single cell and synapse parameters and offers an efficient approach to
analyzing cortical circuits and computations.


title: On Slow-roll Glueball Inflation from Holography

abstract:
  We investigate glueball inflation model-building via the methods of the
gauge/gravity duality. For that purpose, we consider a certain 5d consistent
truncation of type IIB supergravity. This theory admits a solution, whose
metric is of the form of a $dS_4$ fibration over a fifth dimension. We find a
new time-dependent deformation around this solution, which allows for a small
$\eta$ parameter of the corresponding inflationary model. This resolves a
problem with a previous solution that allowed only $\eta$ of order one and thus
gave only an ultra-slow roll regime, but not regular slow roll.


title: Real-time calibration and alignment of the LHCb RICH detectors

abstract:
  In 2015, the LHCb experiment established a new and unique software trigger
strategy with the purpose of increasing the purity of the signal events by
applying the same algorithms online and offline. To achieve this, real-time
calibration and alignment of all LHCb sub-systems is needed to provide
vertexing, tracking, and particle identification of the best possible quality.
The calibration of the refractive index of the RICH radiators, the calibration
of the Hybrid Photon Detector image, and the alignment of the RICH mirror
system, are reported in this contribution. The stability of the RICH
performance and the particle identification performance are also discussed.


title: Generalized Entropy Concentration for Counts

abstract:
  The phenomenon of entropy concentration provides strong support for the
maximum entropy method, MaxEnt, for inferring a probability vector from
information in the form of constraints. Here we extend this phenomenon, in a
discrete setting, to non-negative integral vectors not necessarily summing to
1. We show that linear constraints that simply bound the allowable sums suffice
for concentration to occur even in this setting. This requires a new,
`generalized' entropy measure in which the sum of the vector plays a role. We
measure the concentration in terms of deviation from the maximum generalized
entropy value, or in terms of the distance from the maximum generalized entropy
vector. We provide non-asymptotic bounds on the concentration in terms of
various parameters, including a tolerance on the constraints which ensures that
they are always satisfied by an integral vector. Generalized entropy
maximization is not only compatible with ordinary MaxEnt, but can also be
considered an extension of it, as it allows us to address problems that cannot
be formulated as MaxEnt problems.

categories: cs.IT math.IT math.ST physics.data-an stat.TH


title: Domain Wall Fermion Simulations with the Exact One-Flavor Algorithm

abstract:
  As algorithmic developments have driven down the cost of simulating
degenerate light quark flavors the relative cost of simulating single quark
flavors with the Rational Hybrid Monte Carlo (RHMC) algorithm has become more
expensive. TWQCD has proposed an exact one-flavor algorithm (EOFA) that allows
for HMC simulations of a single quark flavor without taking a square root of
the fermion determinant. We have independently implemented EOFA in the Columbia
Physics System (CPS) and BAGEL Fermion Sparse-Matrix Library (BFM) for Shamir
and M\"{o}bius domain wall fermions, and begun to optimize and test our
implementation against RHMC. In this talk we discuss the derivation of the EOFA
action, our tests of its equivalence to RHMC, and the current state of our
implementation and optimization. We find, after introducing a novel
preconditioning technique for the EOFA Dirac operator, that EOFA is a factor of
2.4 times faster than RHMC per molecular dynamics trajectory for the strange
quark determinant on an $N_{f} = 2+1$ M\"{o}bius DWF ensemble with physical
quark masses and a $24^{3} \times 64 \times 24$ volume. We expect that further
improvement is possible by retuning the integrator parameters for EOFA and by
continuing to optimize our code.


title: The radiation field in the Gamma Irradiation Facility GIF++ at CERN

abstract:
  The high-luminosity LHC (HL-LHC) upgrade is setting now a new challenge for
particle detector technologies. The increase in luminosity will produce a
particle background in the gas-based muon detectors that is ten times higher
than under conditions at the LHC. The detailed knowledge of the detector
performance in the presence of such a high background is crucial for an
optimized design and efficient operation after the HL-LHC upgrade. A precise
understanding of possible aging effects of detector materials and gases is of
extreme importance. To cope with these challenging requirements, a new Gamma
Irradiation Facility (GIF++) was designed and built at the CERN SPS North Area
as successor of the Gamma Irradiation Facility (GIF) during the Long Shutdown 1
(LS1) period. It features an intense source of 662 keV photons with adjustable
intensity, to simulate continuous background over large areas, and, combined
with a high energy muon beam, to measure detector performance in the presence
of the background. The new GIF++ facility has been operational since spring
2015. In addition to describing the facility and its infrastructure, the goal
of this work is to provide an extensive characterization of the GIF++ photon
field with different configurations of the absorption filters in both the
upstream and downstream irradiation areas. Moreover, the measured results are
benchmarked with Geant4 simulations to enhance the knowledge of the radiation
field. The absorbed dose in air in the facility may reach up to 2.2 Gy/h
directly in front of the irradiator. Of special interest is the low-energy
photon component that develops due to the multiple scattering of photons within
the irradiator and from the concrete walls of the bunker.


title:
Fluctuating hydrodynamics approximation of the stochastic Cowan-Wilson
  model

abstract:
  We consider a stochastic version of the Wilson-Cowan model which accommodates
for discrete populations of excitatory and inhibitory neurons. The model
assumes a finite carrying capacity with the two populations being constant in
size. The master equation that governs the dynamics of the stochastic model is
analyzed by an expansion in powers of the inverse population size, yielding a
coupled pair of non-linear Langevin equations with multiplicative noise.
Gillespie simulations show the validity of the obtained approximation, for the
parameter region where the system exhibits dynamical bistability. We report
analytical progress by silencing the retroaction of the activators on the
inhibitors, while still assigning the parameters so to fall in the region of
deterministic bistability for the excitatory species. The proposed approach
forms the basis of a perturbative generalization which applies to the case
where a modest degree of coupling is restored.


title: Recurrent Neural Radio Anomaly Detection

abstract:
  We introduce a powerful recurrent neural network based method for novelty
detection to the application of detecting radio anomalies. This approach holds
promise in significantly increasing the ability of naive anomaly detection to
detect small anomalies in highly complex complexity multi-user radio bands. We
demonstrate the efficacy of this approach on a number of common real over the
air radio communications bands of interest and quantify detection performance
in terms of probability of detection an false alarm rates across a range of
interference to band power ratios and compare to baseline methods.


title: Two statements on path systems related to quantum minors

abstract:
  In ArXiv:1604.00338[math.QA] we gave a complete combinatorial
characterization of homogeneous quadratic identities for minors of quantum
matrices. It was obtained as a consequence of results on minors of matrices of
a special sort, the so-called path matrices $Path_G$ generated by paths in
special planar directed graphs $G$.
  In this paper we prove two assertions that were stated but left unproved in
ArXiv:1604.00338[math.QA]. The first one says that any minor of $Path_G$ is
determined by a system of disjoint paths, called a flow, in $G$ (generalizing a
similar result of Lindstr\"om's type for the path matrices of Cauchon graphs by
Casteels). The second, more sophisticated, assertion concerns certain
transformations of pairs of flows in $G$.


title: Semi-Supervised Radio Signal Identification

abstract:
  Radio emitter recognition in dense multi-user environments is an important
tool for optimizing spectrum utilization, identifying and minimizing
interference, and enforcing spectrum policy. Radio data is readily available
and easy to obtain from an antenna, but labeled and curated data is often
scarce making supervised learning strategies difficult and time consuming in
practice. We demonstrate that semi-supervised learning techniques can be used
to scale learning beyond supervised datasets, allowing for discerning and
recalling new radio signals by using sparse signal representations based on
both unsupervised and supervised methods for nonlinear feature learning and
clustering methods.


title:
Regularity results for transmission problems with sign-changing
  coefficients: a modal approach

abstract:
  We investigate some scalar transmission problems between a classical positive
material and a negative one, whose physical coefficients are negative. First,
we consider cases where the negative inclusion is a disk in 2d and a ball in
3d. Thanks to asymptotics of Bessel functions (validated numerically), we show
well-posedness but with some possible loses of regularity of the solution
compared to the classical case of transmission problems between two positive
materials. Noticing that the curvature plays a central role, we then explore
the case of flat interfaces in the context of waveguides. In this case, the
transmission problem can also have some loses of regularity, or even be
ill-posed (kernel of infinite dimension).


title: Schur-Weyl Duality for Heisenberg Cosets

abstract:
  Let $V$ be a simple vertex operator algebra containing a rank $n$ Heisenberg
vertex algebra $H$ and let $C=\text{Com}\left( {H}, {V}\right)$ be the coset of
${H}$ in ${V}$. Assuming that the representation categories of interest are
vertex tensor categories in the sense of Huang, Lepowsky and Zhang, a
Schur-Weyl type duality for both simple and indecomposable but reducible
modules is proven. Families of vertex algebra extensions of ${C}$ are found and
every simple ${C}$-module is shown to be contained in at least one
${V}$-module. A corollary of this is that if ${V}$ is rational and
$C_2$-cofinite and CFT-type, and $\text{Com}\left( {C}, {V}\right)$ is a
rational lattice vertex operator algebra, then so is ${C}$. These results are
illustrated with many examples and the $C_1$-cofiniteness of certain
interesting classes of modules is established.


title: StegHash: New Method for Information Hiding in Open Social Networks

abstract:
  In this paper a new method for information hiding in open social networks is
introduced. The method, called StegHash, is based on the use of hashtags in
various open social networks to connect multimedia files (like images, movies,
songs) with embedded hidden messages. The evaluation of the system was
performed on two social media services (Twitter and Instagram) with a simple
environment as a proof of concept. The experiments proved that the initial idea
was correct, thus the proposed system could create a completely new area of
threats in social networks.


title:
Global carbon stocks and potential emissions due to mangrove
  deforestation from 2000 to 2012

abstract:
  Mangrove forests store high densities of organic carbon compared to other
forested ecosystems. High carbon storage coupled with high rates of
deforestation means that mangroves contribute substantially to carbon
emissions. Thus, mangroves are candidates for inclusion in Intended Nationally
Determined Contributions (INDCs) to the UNFCC Payments for Ecosystem Services
(PES) program. This study quantifies two datasets required for INDCs and PES
reporting. These are annual mangrove carbon stocks from 2000 to 2012 at the
global, national, and sub-national levels and global carbon emissions resulting
from deforestation. Mangroves stored 4.19 Pg of carbon in 2012, with Indonesia,
Brazil, Malaysia, and Papua New Guinea accounting for greater than 50% of this
stock. 2.96 Pg of the global carbon stock is contained within the soil and 1.23
Pg in the living biomass. Two percent of global mangrove carbon was lost
between 2000 and 2012, equivalent to a maximum potential of 316,996,250 t of
CO2 emissions.


title: A naturally stable Sagnac-Michelson nonlinear interferometer

abstract:
  Interferometers measure a wide variety of dynamic processes by converting a
phase change into an intensity change. Nonlinear interferometers, making use of
nonlinear media in lieu of beamsplitters, promise substantial improvement in
the quest to reach the ultimate sensitivity limits. Here we demonstrate a new
nonlinear interferometer utilizing a single parametric amplifier for mode
mixing---conceptually, a nonlinear version of the conventional Michelson
interferometer with its arms collapsed together. We observe up to 99.9\%
interference visibility and find evidence for noise reduction based on
phase-sensitive gain. Our configuration utilizes fewer components than previous
demonstrations and requires no active stabilization, offering new capabilities
for practical nonlinear interferometric-based sensors.


title: Missing Fe: hydrogenated iron nanoparticles

abstract:
  Although it was found that the FeH lines exist in the spectra of some stars,
none of the spectral features in the ISM have been assigned to this molecule.
We suggest that iron atoms interact with hydrogen and produce Fe-H
nanoparticles which sometimes contain many H atoms. We calculate infrared
spectra of hydrogenated iron nanoparticles using density functional theory
methods and find broad, overlapping bands. Desorption of H2 could induce
spinning of these small Fe-H dust grains. Some of hydrogenated iron
nanoparticles posses magnetic and electric moments and should interact with
electromagnetic fields in the ISM. Fe_nH_m nanoparticles could contribute to
the polarization of the ISM and the anomalous microwave emission. We discuss
the conditions required to form FeH and Fe_nH_m in the ISM.

categories: astro-ph.SR astro-ph.GA cond-mat.mtrl-sci physics.chem-ph


title: Particle Scattering off of Right-Handed Dispersive Waves

abstract:
  Resonant scattering of fast particles off low frequency plasma waves is a
major process determining transport characteristics of energetic particles in
the heliosphere and contributing to their acceleration. Usually, only Alfv\'en
waves are considered for this process, although dispersive waves are also
present throughout the heliosphere. We investigate resonant interaction of
energetic electrons with dispersive, right-handed waves. For the interaction of
particles and a single wave a variable transformation into the rest frame of
the wave can be performed. Here, wellestablished analytic models derived in the
framework of magnetostatic quasi-linear theory (QLT) can be used as a reference
to validate simulation results. However, this approach fails as soon as several
dispersive waves are involved. Based on analytic solutions modeling the
scattering amplitude in the magnetostatic limit, we present an approach to
modify these equations for the use in the plasma frame. Thereby we aim at a
description of particle scattering in the presence of several waves. A
Particle-in-Cell (PiC) code is employed to study wave-particle scattering on a
micro-physically correct level and to test the modified model equations. We
investigate the interactions of electrons at different energies (from 1 keV to
1 MeV) and right-handed waves with various amplitudes. Differences between
model and simulation arise in the case of high amplitudes or several waves.
Analyzing the trajectories of single particles we find no microscopic diffusion
in the case of a single plasma wave, although a broadening of the particle
distribution can be observed.


title: Degenerate Classical Field Theories and Boundary Theories

abstract:
  We introduce a framework for degenerate classical field theories in the BV
formalism, which allows us to discuss many interesting examples of theories
which do not admit a Lagrangian description. Further, we study phase spaces and
boundary conditions for classical field theories on manifolds with boundary,
and from a fixed classical field theory together with a choice of boundary
condition, construct a degenerate classical field theory on the boundary. We
apply these ideas to many physically interesting examples including the
Kapustin-Witten twists of N=4 supersymmetric Yang-Mills, Chern-Simons theory,
the chiral Wess-Zumino-Witten model, chiral Toda theory, and a new 3d classical
field theory called Whittaker theory.


title:
Detection of Single vs Multiple Antenna Transmission Systems Using Pilot
  Data

abstract:
  In this paper, we consider the problem of classifying the transmission system
when it is not known a priori whether the transmission is via a single antenna
or multiple antennas. The receiver is assumed to be employed with a known
number of antennas. In a data frame transmitted by most multiple input multiple
output (MIMO) systems, some pilot or training data is inserted for symbol
timing synchronization and estimation of the channel. Our goal is to perform
MIMO transmit antenna classification using this pilot data. More specifically,
the problem of determining the transmission system is cast as a multiple
hypothesis testing problem where the number of hypotheses is equal to the
maximum number of transmit antennas. Under the assumption of receiver having
the exact knowledge of pilot data used for timing synchronization and channel
estimation, we consider maximum likelihood (ML) and correlation test statistics
to classify the MIMO transmit system. When only probabilistic knowledge of
pilot data is available at the receiver, a hybrid-maximum likelihood (HML)
based test statistic is constructed using the expectation-maximization (EM)
algorithm. The performance of the proposed algorithms is illustrated via
simulations and comparative merits of different techniques in terms of the
computational complexity and performance are discussed.


title:
A new foreperiod effect on single-trial phase coherence. Part I:
  existence and relevance

abstract:
  Expecting events in time leads to more efficient behavior. A remarkable early
finding in the study of temporal expectancy is the foreperiod effect on
reaction times; i.e., the influence or reaction time of the time period between
a warning signal and an imperative stimulus to which subjects are instructed to
respond as quickly as possible. Recently it has been shown that the phase of
oscillatory activity preceding stimulus presentation is related to behavior.
Here we connect both of these findings by reporting a novel foreperiod effect
on the inter-trial phase coherence of the electroencephalogram (EEG) triggered
by stimuli to which subjects are instructed not to respond. Inter-trial phase
coherence has been used to describe regularities in phases of groups of trials
time locked to an event of interest. We propose a single-trial measure of
inter-trial phase coherence and prove its soundness. Equipped with this
measure, and using a multivariate decoding method, we demonstrate that the
foreperiod duration in and audiovisual attention-shifting task modulates
single-trial phase coherence. In principle, this modulation could be an
artifact of the decoding method used to detect it. We show that this is not the
case, since the modulation can also be observed using a simple averaging
method. We show that the strength of this modulation correlates with subject
behavior (both error rates and mean-reaction times). We anticipate that the new
foreperiod effect on inter-trial phase coherence, and the decoding method used
here to detect it, will be important tools to understand cognition at the
single-trial level. In Part II of this manuscript, we support this claim, by
showing that changes in attention modulate the strength of the new foreperiod
effect on a trial-by-trial basis.


title: Hierarchy for groups acting on hyperbolic $\mathbf{Z}^n$-spaces

abstract:
  In their first article, the authors initiated a systematic study of
hyperbolic $\Lambda$-metric spaces, where $\Lambda$ is an ordered abelian
group, and groups acting on such spaces. The present paper concentrates on the
case $\Lambda = \mathbf{Z}^n$ taken with the right lexicographic order and
studies the structure of finitely generated groups acting on hyperbolic
$\mathbf{Z}^n$-metric spaces. Under certain constraints, the structure of such
groups is described in terms of a {\em hierarchy} similar to the one
established for $\mathbf{Z}^n$-free groups by Kharlampovich, Myasnikov,
Remeslennikov and Serbin.


title:
Rapid Prototyping of a Text Mining Application for Cryptocurrency Market
  Intelligence

abstract:
  Blockchain represents a technology for establishing a shared, immutable
version of the truth between a network of participants that do not trust one
another, and therefore has the potential to disrupt any financial or other
industries that rely on third-parties to establish trust. Recent trends in
computing including: prevalence of Free and Open Source Software (FOSS); easy
access to High Performance Computing (HPC i.e. 'The Cloud'); and increasingly
advanced analytics capabilities such as Natural Language Processing (NLP) and
Machine Learning (ML) allow for rapidly prototyping applications for analysis
of trends in the emergence of Blockchain technology. A scaleable
proof-of-concept pipeline that lays the groundwork for analysis of multiple
streams of semi-structured data posted on social media is demonstrated.
Preliminary analysis and performance metrics are presented and discussed.
Future work is described that will scale the system to cloud-based, real-time,
analysis of multiple data streams, with Information Extraction (IE) (ex.
sentiment analysis) and Machine Learning capability.


title:
Essentially high-order compact schemes with application to stochastic
  volatility models on non-uniform grids

abstract:
  We present high-order compact schemes for a linear second-order parabolic
partial differential equation (PDE) with mixed second-order derivative terms in
two spatial dimensions. The schemes are applied to option pricing PDE for a
family of stochastic volatility models. We use a non-uniform grid with more
grid-points around the strike price. The schemes are fourth-order accurate in
space and second-order accurate in time for vanishing correlation. In our
numerical convergence study we achieve fourth-order accuracy also for non-zero
correlation. A combination of Crank-Nicolson and BDF-4 discretisation is
applied in time. Numerical examples confirm that a standard, second-order
finite difference scheme is significantly outperformed.


title: Overview of Spintronic Sensors, Internet of Things, and Smart Living

abstract:
  Smart living is a trending lifestyle that envisions lower energy consumption,
sound public services, and better quality of life for human being. The Internet
of Things (IoT) is a compelling platform connecting various sensors around us
to the Internet, providing great opportunities for the realization of smart
living. Spintronic sensors with superb measuring ability and multiple unique
advantages can be an important piece of cornerstone for IoT. In this review, we
discuss successful applications of spintronic sensors in electrical current
sensing, transmission and distribution lines monitoring, vehicle detection, and
biodetection. Traditional monitoring systems with limited sensors and wired
communication can merely collect fragmented data in the application domains. In
this paper, the wireless spintronic sensor networks (WSSNs) will be proposed
and illustrated to provide pervasive monitoring systems, which facilitate the
intelligent surveillance and management over building, power grid, transport,
and healthcare. The database of collected information will be of great use to
the policy making in public services and city planning. This work provides
insights for realizing smart living through the integration of IoT with
spintronic sensor technology.


title:
Fermi-surface topologies and low-temperature phases of the filled
  Skutterudite compounds CeOs$_4$Sb$_{12}$ and NdOs$_4$Sb$_{12}$

abstract:
  MHz conductivity, torque magnetometer and magnetization measurements are
reported on single crystals of CeOs$_4$Sb$_{12}$ and NdOs$_4$Sb$_{12}$ using
temperatures down to 0.5~K and magnetic fields of up to 60~tesla. The
field-orientation dependence of the de Haas-van Alphen and Shubnikov-de Haas
oscillations is deduced by rotating the samples about the $[010]$ and
$[0\bar{1}1]$ directions. The results indicate that NdOs$_4$Sb$_{12}$ has a
similar Fermi surface topology to that of the unusual superconductor
PrOs$_4$Sb$_{12}$, but with significantly smaller effective masses, supporting
the importance of local phonon modes in contributing to the low-temperature
heat capacity of NdOs$_4$Sb$_{12}$. By contrast, CeOs$_4$Sb$_{12}$ undergoes a
field-induced transition from an unusual semimetal into a high-field,
high-temperature state characterized by a single, almost spherical
Fermi-surface section. The behavior of the phase boundary and comparisons with
models of the bandstructure lead us to propose that the field-induced phase
transition in CeOs$_4$Sb$_{12}$ is similar in origin to the well-known
$\alpha-\gamma$ transition in Ce and its alloys.


title: A deterministic particle approximation for non-linear conservation laws

abstract:
  We review our analytical and numerical results obtained on the microscopic
Follow-The-Leader (FTL) many particle approximation of one-dimensional
conservation laws. More precisely, we introduce deterministic particle schemes
for the Hughes model for pedestrian movements and for two vehicular traffic
models, that are the scalar Lighthill-Whitham-Richards model (LWR) and the
$2\times2$ system Aw-Rascle-Zhang model (ARZ). Their approximation is performed
by a set of ODEs, determining the motion of platoons of possible fractional
vehicles or pedestrians seen as particles. Convergence results of the schemes
in the many particle limit are stated. The numerical simulations suggest the
consistency of the schemes.


title: Modeling of charged anisotropic compact stars in general relativity

abstract:
  A charged compact star models have been determined for anisotropic fluid
distribution. We have solved the Einstein's- Maxwell field equations to
construct the charged compact star models by using radial pressure, metric
function $e^{\lambda}$ and electric charge function. The generic charged
anisotropic solution is verified by exploring different physical conditions
like, causality condition, mass-radius relation and stability of the solution
(via. adiabatic index, TOV equations and Herrera cracking concept). It is
observed that the present charged anisotropic compact star is compatible with
the star PSR 1937+21. However we also presented the EOS $\rho=f(p)$ for present
charged compact star model.


title:
Energy Efficiency Optimization with Simultaneous Wireless Information
  and Power Transfer in MIMO Broadcast Channels

abstract:
  Simultaneous wireless information and power transfer (SWIPT) is anticipated
to have great applications in fifth-generation (5G) and beyond communication
systems. In this paper, we address the energy efficiency (EE) optimization
problem for SWIPT multiple-input multiple-output broadcast channel (MIMO-BC)
with time-switching (TS) receiver design. Our aim is to maximize the EE of the
system whilst satisfying certain constraints in terms of maximum transmit power
and minimum harvested energy per user. The coupling of the optimization
variables, namely, transmit covariance matrices and TS ratios, leads to a EE
problem which is non-convex, and hence very difficult to solve directly. Hence,
we transform the original maximization problem with multiple constraints into a
min-max problem with a single constraint and multiple auxiliary variables. We
propose a dual inner/outer layer resource allocation framework to tackle the
problem. For the inner-layer, we invoke an extended SWIPT-based BC-multiple
access channel (MAC) duality approach and provide two iterative resource
allocation schemes under fixed auxiliary variables for solving the dual MAC
problem. A sub-gradient searching scheme is then proposed for the outer-layer
in order to obtain the optimal auxiliary variables. Numerical results confirm
the effectiveness of the proposed algorithms and illustrate that significant
performance gain in terms of EE can be achieved by adopting the proposed
extended BC-MAC duality-based algorithm.


title: Variational structure of the $v_{\frac{n}{2}}$-Yamabe problem

abstract:
  We define a new formal Riemannian metric on a conformal class in the context
of the $v_{\frac{n}{2}}$-Yamabe problem. Our construction leads to a new
variational characterization and a new parabolic flow approach to this problem.
Moreover, this variational framework suggests that solutions to this problem
are unique in a given conformal class.


title: Self-Awareness of Cloud Applications

abstract:
  Cloud applications today deliver an increasingly larger portion of the
Information and Communication Technology (ICT) services. To address the scale,
growth, and reliability of cloud applications, self-aware management and
scheduling are becoming commonplace. How are they used in practice? In this
chapter, we propose a conceptual framework for analyzing state-of-the-art
self-awareness approaches used in the context of cloud applications. We map
important applications corresponding to popular and emerging application
domains to this conceptual framework, and compare the practical
characteristics, benefits, and drawbacks of self-awareness approaches. Last, we
propose a roadmap for addressing open challenges in self-aware cloud and
datacenter applications.


title:
Definitive ideal-gas thermochemical functions of the H$_2$$^{16}$O
  molecule

abstract:
  $Q_{\rm int}$($T$), of the H$_2$$^{16}$O molecule is reported for
temperatures between 0 and 6000 K. Determination of $Q_{\rm int}$($T$) is
principally based on the direct summation technique involving all accurate
experimental energy levels known for H$_2$$^{16}$O (almost 20~000 rovibrational
energies including an almost complete list up to a relative energy of 7500
\cm), augmented with a less accurate but complete list of first-principles
computed rovibrational energy levels up to the first dissociation limit, about
41~000 \cm\ (the latter list includes close to one million bound rovibrational
energy levels up to $J = 69$, where $J$ is the rotational quantum number).
Partition functions are developed for {\it ortho}- and {\it para}-H$_2$$^{16}$O
as well as for their equilibrium mixture. Unbound rovibrational states above
the first dissociation limit are considered using an approximate model
treatment. The effect of the excited electronic states on the thermochemical
functions is neglected, as their contribution to the thermochemical functions
is negligible even at the highest temperatures considered. Based on the
high-accuracy $Q_{\rm int}$($T$) and its first two moments, definitive results,
in 1~K increments, are obtained for the following thermochemical functions:
Gibbs energy, standardized enthalpy, entropy, and isobaric heat capacity.
Reliable approximately two standard deviation uncertainties, as a function of
temperature, are estimated for each quantity determined. These uncertainties
emphasize that the present results are the most accurate ideal-gas
thermochemical functions ever produced for H$_2$$^{16}$O. It is recommended
that the new value determined for the standard molar enthalpy increment at
298.15~K, $9.90404 \pm 0.00001$ kJ~mol$^{-1}$, should replace the old CODATA
datum, $9.905 \pm 0.005$ kJ~mol$^{-1}$.


title: Neutrino Mass, Electron Capture and the Shake-off Contributions

abstract:
  Electron capture can determine the electron neutrino mass, while the beta
decay of Tritium measures the electron antineutrino mass and the neutrinoless
double beta decay observes the Majorana neutrino mass. Electron capture e. g.
on 163Ho plus bound electron to 163Dy* plus neutrino can determine the electron
neutrino mass from the upper end of the decay spectrum of the excited Dy*,
which is given by the Q-Value minus the neutrino mass. The Dy* states decay by
X-ray and Auger electron emissions. The total decay energy is measured in a
bolometer. These excitations have been studied by Robertson and by Faessler et
al.. In addition the daughter atom Dy can also be excited by moving in the
capture process one electron into the continuum. The escape of these continuum
electrons is automatically included in the experimental bolometer spectrum.
Recently a method developed by Intemann and Pollock was used by DeRujula and
Lusignoli for a rough estimate of this shake-off process for "s" wave electrons
in capture on 163Ho. The purpose of the present work is to give a more reliable
description of "s" wave shake-off in electron capture on Holmium. For that one
needs very accurate atomic wave functions of Ho in its ground state and excited
atomic wave functions of Dy* including a description of the continuum
electrons. In the present approach the wave functions of Ho and Dy* are
determined selfconsistently with the antisymmetrized relativistic
Dirac-Hartree-Fock approach. The relativistic continuum electron wave functions
for the ionized Dy* are obtained in the corresponding selfconsistent
Dirac-Hartree-Fock-Potential. In this improved approach shake-off can hardly be
seen after electron capture in 163Ho and thus can probably not affect the
determination of the electron neutrino mass.


title:
Enhanced Factored Three-Way Restricted Boltzmann Machines for Speech
  Detection

abstract:
  In this letter, we propose enhanced factored three way restricted Boltzmann
machines (EFTW-RBMs) for speech detection. The proposed model incorporates
conditional feature learning by multiplying the dynamical state of the third
unit, which allows a modulation over the visible-hidden node pairs. Instead of
stacking previous frames of speech as the third unit in a recursive manner, the
correlation related weighting coefficients are assigned to the contextual
neighboring frames. Specifically, a threshold function is designed to capture
the long-term features and blend the globally stored speech structure. A
factored low rank approximation is introduced to reduce the parameters of the
three-dimensional interaction tensor, on which non-negative constraint is
imposed to address the sparsity characteristic. The validations through the
area-under-ROC-curve (AUC) and signal distortion ratio (SDR) show that our
approach outperforms several existing 1D and 2D (i.e., time and time-frequency
domain) speech detection algorithms in various noisy environments.


title:
Turbulent compressible fluid: renormalization group analysis, scaling
  regimes, and anomalous scaling of advected scalar fields

abstract:
  We study a model of fully developed turbulence of a compressible fluid, based
on the stochastic Navier-Stokes equation, by means of the field theoretic
renormalization group. In this approach, scaling properties are related to the
fixed points of the renormalization group equations. Previous analysis of this
model near the real-world space dimension 3 identified some scaling regime
[Theor. Math. Phys., 110, 3 (1997)]. The aim of the present paper is to explore
the existence of additional regimes, that could not be found using the direct
perturbative approach of the previous work, and to analyze the crossover
between different regimes. It seems possible to determine them near the special
value of space dimension $4$ in the framework of double $y$ and $\varepsilon$
expansion, where $y$ is the exponent associated with the random force and
$\varepsilon=4-d$ is the deviation from the space dimension $4$. Our
calculations show that there exists an additional fixed point that governs
scaling behavior. Turbulent advection of a passive scalar (density) field by
this velocity ensemble is considered as well. We demonstrate that various
correlation functions of the scalar field exhibit anomalous scaling behavior in
the inertial-convective range. The corresponding anomalous exponents,
identified as scaling dimensions of certain composite fields, can be
systematically calculated as a series in $y$ and $\varepsilon$. All
calculations are performed in the leading one-loop approximation.


title: Variational Inference via $\chi$-Upper Bound Minimization

abstract:
  Variational inference (VI) is widely used as an efficient alternative to
Markov chain Monte Carlo. It posits a family of approximating distributions $q$
and finds the closest member to the exact posterior $p$. Closeness is usually
measured via a divergence $D(q || p)$ from $q$ to $p$. While successful, this
approach also has problems. Notably, it typically leads to underestimation of
the posterior variance. In this paper we propose CHIVI, a black-box variational
inference algorithm that minimizes $D_{\chi}(p || q)$, the $\chi$-divergence
from $p$ to $q$. CHIVI minimizes an upper bound of the model evidence, which we
term the $\chi$ upper bound (CUBO). Minimizing the CUBO leads to improved
posterior uncertainty, and it can also be used with the classical VI lower
bound (ELBO) to provide a sandwich estimate of the model evidence. We study
CHIVI on three models: probit regression, Gaussian process classification, and
a Cox process model of basketball plays. When compared to expectation
propagation and classical VI, CHIVI produces better error rates and more
accurate estimates of posterior variance.


title: Collectivity in small collision systems : an initial state perspective

abstract:
  Measurements of multi-particle correlations in the collisions of small
systems such as $p+p$, $p/d/^3He+A$ show striking similarity to the
observations in heavy ion collisions. A number of observables measured in the
high multiplicity events of these systems resemble features that are attributed
to collectivity driven by hydrodynamics. However alternative explanations based
on initial state dynamics are able to describe many characteristic features of
these measurements. In this brief review we highlight some of the recent
developments and outstanding issues in this direction.


title: New non-arithmetic complex hyperbolic lattices II

abstract:
  We describe a general procedure to produce fundamental domains for complex
hyperbolic triangle groups, a class of groups that contains a representative of
the commensurability class of every known non-arithmetic lattice in ${\rm
PU}(2,1)$. We discuss several commensurability invariants for lattices, and
show that some triangle groups yield new commensurability classes, bringing the
number of known non-arithmetic commensurability classes to 22.


title:
Low Cost Autonomous Navigation and Control of a Mechanically Balanced
  Bicycle with Dual Locomotion Mode

abstract:
  On the lines of the huge and varied efforts in the field of automation with
respect to technology development and innovation of vehicles to make them run
autonomously, this paper presents an innovation to a bicycle. A normal daily
use bicycle was modified at low cost such that it runs autonomously, while
maintaining its original form i.e. the manual drive. Hence, a bicycle which
could be normally driven by any human and with a press of switch could run
autonomously according to the needs of the user has been developed.


title:
Hierarchical data-driven approach to fitting numerical relativity data
  for nonprecessing binary black holes with an application to final spin and
  radiated energy

abstract:
  Numerical relativity is an essential tool in studying the coalescence of
binary black holes (BBHs). It is still computationally prohibitive to cover the
BBH parameter space exhaustively, making phenomenological fitting formulas for
BBH waveforms and final-state properties important for practical applications.
We describe a general hierarchical bottom-up fitting methodology to design and
calibrate fits to numerical relativity simulations for the three-dimensional
parameter space of quasicircular nonprecessing merging BBHs, spanned by mass
ratio and by the individual spin components orthogonal to the orbital plane.
Particular attention is paid to incorporating the extreme-mass-ratio limit and
to the subdominant unequal-spin effects. As an illustration of the method, we
provide two applications, to the final spin and final mass (or equivalently:
radiated energy) of the remnant black hole. Fitting to 427 numerical relativity
simulations, we obtain results broadly consistent with previously published
fits, but improving in overall accuracy and particularly in the approach to
extremal limits and for unequal-spin configurations. We also discuss the
importance of data quality studies when combining simulations from diverse
sources, how detailed error budgets will be necessary for further improvements
of these already highly accurate fits, and how this first detailed study of
unequal-spin effects helps in choosing the most informative parameters for
future numerical relativity runs.


title: On uniqueness of dissipative solutions of the Camassa-Holm equation

abstract:
  We prove that dissipative weak solutions of the Camassa-Holm equation are
unique. Thus we complete the global well-posedness theory of this celebrated
model of shallow water, initiated by a general proof of existence in [Z. Xin,
P. Zhang Comm. Pure Appl. Math. 53 (2000)]. As the dissipative weak solutions,
being viscosity solutions, seem to constitute the most physically relevant
class of solutions in the wave-breaking regime, the result provides
mathematical rationale for the feasibility of the Camassa-Holm equation as a
model of water waves encompassing both soliton interactions and wave-breaking.


title:
The effects of near-core convective shells on the gravity modes of the
  subdwarf B pulsator KIC 10553698A

abstract:
  KIC 10553698A is a hot pulsating subdwarf B (sdB) star observed by the Kepler
satellite. It exhibits dipole (l = 1) and quadrupole (l = 2) gravity modes with
a clear period spacing structure. The seismic properties of the KIC 10553698A
provide a test of stellar evolution models, and offer a unique opportunity to
determine mixing processes. We consider mixing due to convective overshooting
beyond the boundary of the helium burning core. Very small overshooting ( f =
10^{-6} ) results in a progressive increase in the size of convective core.
However, moderate ( f = 10^{-2} ) and small ( f = 10^{-5} ) overshooting both
lead to the occurrence of inert outer convective shells in the near-core
region. We illustrate that the chemical stratifications induced by convective
shells are able to change the g-mode period spacing pattern of a sdB star
appreciably. The mean period spacing and trapping of the gravity modes in the
model with moderate and small core overshooting are fully consistent with the
period spacing trends observed in KIC 10553698A. Atomic diffusion driven by
gravitational settling as well as thermal and chemical gradients is applied to
reach a better match with the observed period spacings. Models that include
small or very small overshooting with atomic diffusion have a decreased
lifetime of the extreme horizontal branch phase and produce chemical
stratification induced by convective shells during helium burning phase. In
addition of being consistent with asteroseismology, their calculated values of
the R2 parameter are more compatible with the observed R2 values.


title: Fiber laser system for cesium and rubidium atom interferometry

abstract:
  We present an innovative fiber laser system for both cesium and rubidium
manipulation. The architecture is based on frequency conversion of two lasers
at 1560 nm and 1878 nm. By taking advantage of existing fiber components at
these wavelengths, we demonstrate an all fiber laser system delivering 350 mW
at 780 nm for rubidium and 210 mW at 852 nm for cesium. This result highlights
the promising nature of such laser system especially for Cs manipulation for
which no fiber laser system has been reported. It offers new perspectives for
the development of atomic instruments dedicated to onboard applications and
opens the way to a new generation of atom interferometers involving three
atomic species $^{85}$Rb, $^{87}$Rb and $^{133}$Cs for which we propose an
original laser architecture.


title: Stochastic Variational Deep Kernel Learning

abstract:
  Deep kernel learning combines the non-parametric flexibility of kernel
methods with the inductive biases of deep learning architectures. We propose a
novel deep kernel learning model and stochastic variational inference procedure
which generalizes deep kernel learning approaches to enable classification,
multi-task learning, additive covariance structures, and stochastic gradient
training. Specifically, we apply additive base kernels to subsets of output
features from deep neural architectures, and jointly learn the parameters of
the base kernels and deep network through a Gaussian process marginal
likelihood objective. Within this framework, we derive an efficient form of
stochastic variational inference which leverages local kernel interpolation,
inducing points, and structure exploiting algebra. We show improved performance
over stand alone deep networks, SVMs, and state of the art scalable Gaussian
processes on several classification benchmarks, including an airline delay
dataset containing 6 million training points, CIFAR, and ImageNet.


title: An alternative proof of Kazhdan property for elementary groups

abstract:
  In 2010, Invent. Math., Ershov and Jaikin-Zapirain proved Kazhdan's property
(T) for elementary groups. This expository article focuses on presenting an
alternative simpler proof of that. Unlike the original one, our proof supplies
no estimate of Kazhdan constants. It may be regarded as a specific example of
the results in the paper "Upgrading fixed points without bounded generation"
(arXiv:1505.06728, forthcoming version) by the author.


title:
A search for new phenomena in pp collisions at sqrt(s) = 13 TeV in final
  states with missing transverse momentum and at least one jet using the alphaT
  variable

abstract:
  A search for new phenomena is performed in final states containing one or
more jets and an imbalance in transverse momentum in pp collisions at a
centre-of-mass energy of 13 TeV. The analysed data sample, recorded with the
CMS detector at the CERN LHC, corresponds to an integrated luminosity of 2.3
inverse femtobarns. Several kinematic variables are employed to suppress the
dominant background, multijet production, as well as to discriminate between
other standard model and new physics processes. The search provides sensitivity
to a broad range of new-physics models that yield a stable weakly interacting
massive particle. The number of observed candidate events is found to agree
with the expected contributions from standard model processes, and the result
is interpreted in the mass parameter space of fourteen simplified
supersymmetric models that assume the pair production of gluinos or squarks and
a range of decay modes. For models that assume gluino pair production, masses
up to 1575 and 975 GeV are excluded for gluinos and neutralinos, respectively.
For models involving the pair production of top squarks and compressed mass
spectra, top squark masses up to 400 GeV are excluded.


title: On Event Reduction in Localization of DES Supervisory Control

abstract:
  Supervisor localization procedure can be used to construct local controllers
corresponding to each component agent in discrete-event systems. This procedure
is based on state reduction of a monolithic supervisor with respect to each set
of controllable events corresponding to each component agent. State reduction
from the reduced supervisor to each local controller is an important criterion.
In this paper, we deal with event reduction. It is proved that the number of
events in each local controller is less than the event cardinality in the
reduced supervisor, provided that each local controller has less number of
states comparing to the reduced supervisor. It shows that each local controller
needs less number of events to make consistent decisions. Having this property,
we can evaluate the localizability of a supervisor by event reduction criteria
instead of state reduction criteria. State reduction facilitates the
implementation of local controllers on industrial systems. Whereas, event
reduction reduces communication traffic between each pair of local controllers.


title: Variational Bayes In Private Settings (VIPS)

abstract:
  Many applications of Bayesian data analysis involve sensitive information,
motivating methods which ensure that privacy is protected. We introduce a
general privacy-preserving framework for Variational Bayes (VB), a widely used
optimization-based Bayesian inference method. Our framework respects
differential privacy, the gold-standard privacy criterion, and encompasses a
large class of probabilistic models, called the Conjugate Exponential (CE)
family. We observe that we can straightforwardly privatise VB's approximate
posterior distributions for models in the CE family, by perturbing the expected
sufficient statistics of the complete-data likelihood. For a broadly-used class
of non-CE models, those with binomial likelihoods, we show how to bring such
models into the CE family, such that inferences in the modified model resemble
the private variational Bayes algorithm as closely as possible, using the
Polya-Gamma data augmentation scheme. The iterative nature of variational Bayes
presents a further challenge since iterations increase the amount of noise
needed. We overcome this by combining: (1) an improved composition method for
differential privacy, called the moments accountant, which provides a tight
bound on the privacy cost of multiple VB iterations and thus significantly
decreases the amount of additive noise; and (2) the privacy amplification
effect of subsampling mini-batches from large-scale data in stochastic
learning. We empirically demonstrate the effectiveness of our method in CE and
non-CE models including latent Dirichlet allocation, Bayesian logistic
regression, and sigmoid belief networks, evaluated on real-world datasets.


title: Minidisks in Binary Black Hole Accretion

abstract:
  Newtonian simulations have demonstrated that accretion onto binary black
holes produces accretion disks around each black hole ("minidisks"), fed by gas
streams flowing through the circumbinary cavity from the surrounding
circumbinary disk. We study the dynamics and radiation of an individual black
hole minidisk using two-dimensional hydrodynamical simulations performed with a
new general relativistic version of the moving mesh code Disco. We introduce a
co-moving energy variable which enables highly accurate integration of these
high Mach number flows. Tidally induced spiral shock waves are excited in the
disk and propagate through the ISCO providing a Reynolds stress which causes
efficient accretion by purely hydrodynamic means and producing a radiative
signature brighter in hard X-rays than the Novikov-Thorne model. Disk cooling
is provided by a local blackbody prescription that allows the disk to evolve
self-consistently to a temperature profile where hydrodynamic heating is
balanced by radiative cooling. We find that the spiral shock structure is in
agreement with the relativistic dispersion relation for tightly-wound linear
waves. We measure the shock induced dissipation and find outward angular
momentum transport corresponding to an effective alpha parameter of order 0.01.
We perform ray-tracing image calculations from the simulations to produce
theoretical minidisk spectra and viewing angle dependent images for comparison
with observations.


title: Holographic Corrections to Meson Scattering Amplitudes

abstract:
  We compute meson scattering amplitudes using the holographic duality between
confining gauge theories and string theory, in order to consider holographic
corrections to the Veneziano amplitude and associated higher-point functions.
The generic nature of such computations is explained, thanks to the
well-understood nature of confining string backgrounds, and two different
examples of the calculation in given backgrounds are used to illustrate the
details. The effect we discover, whilst only qualitative, is re-obtainable in
many such examples, in four-point but also higher point amplitudes.


title: Symplectic Modeling of Beam Loading in Electromagnetic Cavities

abstract:
  Simulating beam loading in radiofrequency accelerating structures is critical
for understanding higher-order mode effects on beam dynamics, such as beam
break-up instability in energy recovery linacs. Full wave simulations of beam
loading in radiofrequency structures are computationally expensive, while
reduced models can ignore essential physics and can be difficult to generalize.
We present a self-consistent algorithm derived from the least-action principle
which can model an arbitrary number of cavity eigenmodes and with a generic
beam distribution.