title:
A General Method to Determine Limiting Optimal Shapes for
  Edge-Isoperimetric Inequalities

abstract:
  For a general family of graphs on $\mathbb{Z}^n$, we translate the
edge-isoperimetric problem into a continuous isoperimetric problem in
$\mathbb{R}^n$. We then solve the continuous isoperimetric problem using the
Brunn-Minkowski inequality and Minkowski's theorem on Mixed Volumes. This
translation allows us to conclude, under a reasonable assumption about the
discrete problem, that the shapes of the optimal sets in the discrete problem
approach the shape of the optimal set in the continuous problem as the size of
the set grows. The solution is the zonotope defined as the Minkowski sum of the
edges of the original graph.
  We demonstrate the efficacy of this method by revisiting some previously
solved classical edge-isoperimetric problems. We then apply our method to some
discrete isoperimetric problems which had not previously been solved. The
complexity of those solutions suggest that it would be quite difficult to find
them using discrete methods only.


title:
Deep Double Sparsity Encoder: Learning to Sparsify Not Only Features But
  Also Parameters

abstract:
  This paper emphasizes the significance to jointly exploit the problem
structure and the parameter structure, in the context of deep modeling. As a
specific and interesting example, we describe the deep double sparsity encoder
(DDSE), which is inspired by the double sparsity model for dictionary learning.
DDSE simultaneously sparsities the output features and the learned model
parameters, under one unified framework. In addition to its intuitive model
interpretation, DDSE also possesses compact model size and low complexity.
Extensive simulations compare DDSE with several carefully-designed baselines,
and verify the consistently superior performance of DDSE. We further apply DDSE
to the novel application domain of brain encoding, with promising preliminary
results achieved.


title: On the Lifting of the Dirac Elements in the Higson-Kasparov Theorem

abstract:
  In this thesis, we investigate the proof of the Baum-Connes Conjecture with
Coefficients for a-$T$-menable groups. We will mostly and essentially follow
the argument employed by N. Higson and G. Kasparov in the paper [Nigel Higson
and Gennadi Kasparov. $E$-theory and $KK$-theory for groups which act properly
and isometrically on Hilbert space. Invent. Math., 144(1):23-74, 2001]. The
crucial feature is as follows. One of the most important point of their proof
is how to get the Dirac elements (the inverse of the Bott elements) in
Equivariant $KK$-Theory. We prove that the group homomorphism used for the
lifting of the Dirac elements is an isomorphism in the case of our interests.
Hence, we get a clear and simple understanding of the lifting of the Dirac
elements in the Higson-Kasparov Theorem. In the course of our investigation, on
the other hand, we point out a problem and give a fixed precise definition for
the non-commutative functional calculus which is defined in the paper In the
final part, we mention that the $C^*$-algebra of (real) Hilbert space becomes a
$G$-$C^*$-algebra naturally even when a group $G$ acts on the Hilbert space by
an affine action whose linear part is of the form an isometry times a scalar
and prove the infinite dimensional Bott-Periodicity in this case by using
Fell's absorption technique.


title: L\'evy-Vasicek Models and the Long-Bond Return Process

abstract:
  The classical derivation of the well-known Vasicek model for interest rates
is reformulated in terms of the associated pricing kernel. An advantage of the
pricing kernel method is that it allows one to generalize the construction to
the L\'evy-Vasicek case, avoiding issues of market incompleteness. In the
L\'evy-Vasicek model the short rate is taken in the real-world measure to be a
mean-reverting process with a general one-dimensional L\'evy driver admitting
exponential moments. Expressions are obtained for the L\'evy-Vasicek bond
prices and interest rates, along with a formula for the return on a unit
investment in the long bond, defined by $L_t = \lim_{T \rightarrow \infty}
P_{tT} / P_{0T}$, where $P_{tT}$ is the price at time $t$ of a $T$-maturity
discount bond. We show that the pricing kernel of a L\'evy-Vasicek model is
uniformly integrable if and only if the long rate of interest is strictly
positive.


title:
Hawking Radiation of Vector Particles via Tunneling From 4-Dimensional
  And 5-Dimensional Black Holes

abstract:
  Using Proca equation and WKB approximation, we investigate Hawking radiation
of vector particles via tunneling from 4-dimensional Kerr-de Sitter black hole
and 5-dimensional Schwarzschild-Tangherlini black hole. The results show that
the tunneling rates and Hawking temperatures are depended on the properties of
spacetime (event horizon, mass and angular momentum). Besides, our results are
the same as scalars and fermions tunneling from 4-dimensional Kerr-de Sitter
black hole and 5-dimensional Schwarzschild-Tangherlini black hole.


title:
Towards Machine Comprehension of Spoken Content: Initial TOEFL Listening
  Comprehension Test by Machine

abstract:
  Multimedia or spoken content presents more attractive information than plain
text content, but it's more difficult to display on a screen and be selected by
a user. As a result, accessing large collections of the former is much more
difficult and time-consuming than the latter for humans. It's highly attractive
to develop a machine which can automatically understand spoken content and
summarize the key information for humans to browse over. In this endeavor, we
propose a new task of machine comprehension of spoken content. We define the
initial goal as the listening comprehension test of TOEFL, a challenging
academic English examination for English learners whose native language is not
English. We further propose an Attention-based Multi-hop Recurrent Neural
Network (AMRNN) architecture for this task, achieving encouraging results in
the initial tests. Initial results also have shown that word-level attention is
probably more robust than sentence-level attention for this task with ASR
errors.


title:
Profile Analyst: Advanced Job Candidate Matching via Automatic Skills
  Linking

abstract:
  The recruitment process is a slow and inefficient one at best, and a
potentially ineffective one at worst. Matching candidates to jobs is one thing,
but matching candidates with jobs alongside appropriate expectations and taking
into account the right aptitude and suitability for any given role is another
thing and in this paper we look at a whole new way of matching jobs with
potential candidates as well as matching against their overall suitability for
a given role.


title:
Fermi Large Area Telescope Observations of the Monoceros Loop Supernova
  Remnant

abstract:
  We present an analysis of the gamma-ray measurements by the Large Area
Telescope onboard the \textit{Fermi Gamma-ray Space Telescope} in the region of
the supernova remnant~(SNR) Monoceros Loop~(G205.5$+$0.5). The brightest
gamma-ray peak is spatially correlated with the Rosette Nebula, which is a
molecular cloud complex adjacent to the southeast edge of the SNR. After
subtraction of this emission by spatial modeling, the gamma-ray emission from
the SNR emerges, which is extended and fit by a Gaussian spatial template. The
gamma-ray spectra are significantly better reproduced by a curved shape than a
simple power law. The luminosities between 0.2--300~GeV are $\sim$~$4 \times
10^{34}$~erg~s$^{-1}$ for the SNR and $\sim$~$3 \times 10^{34}$~erg~s$^{-1}$
for the Rosette Nebula, respectively. We argue that the gamma rays likely
originate from the interactions of particles accelerated in the SNR. The decay
of neutral pions produced in nucleon-nucleon interactions of accelerated
hadrons with interstellar gas provides a reasonable explanation for the
gamma-ray emission of both the Rosette Nebula and the Monoceros SNR.


title:
First-principles study on segregation of ternary additions for
  MoSi2/Mo5Si3 interface

abstract:
  We investigate segregation behavior of additive elements M (= Ni, Cr) at the
C11b/D8m interface for MoSi2- Mo5Si3 alloys, based on first-principles
calculation. We first find energetically stable interface structure with
interface energy of 0.08 eV/A^2. Based on the stable interface, segregation
energy for additive elements is calcu- lated for individual atomic layer, which
is applied to Monte Carlo statistical simulation under grand-canonical ensemble
to quantitatively predict interface segregation profile. We find that our
simulation successfully capture the characteristics in measured segregation
tendency of (i) Similarity in strong segregation at interface both for Ni and
Cr compared with bulk composition, and (ii) stronger segregation for Ni than
for Cr, which can be mainly attributed to differences in calculated segregation
energy. The present results indicate that measured segregated interface for
MoSi2-Mo5Si3 alloys can be thermodynamically stable.


title:
AMS-02 Positron Excess and Indirect Detection of Three-body Decaying
  Dark Matter

abstract:
  We consider indirect detection of meta-stable dark matter particles decaying
into a stable neutral particle and a pair of standard model fermions. Due to
the softer energy spectra from the three-body decay, such models could
potentially explain the AMS-02 positron excess without being constrained by the
Fermi-LAT gamma-ray data and the cosmic ray anti-proton measurements. We
scrutinize over different final state fermions, paying special attention to
handling of the cosmic ray background and including various contributions from
cosmic ray propagation with the help of the \textsc{LikeDM} package. It is
found that primary decays into an electron-positron pair and a stable neutral
particle could give rise to the AMS-02 positron excess and, at the same time,
stay unscathed against the gamma-ray and anti-proton constraints. Decays to a
muon pair or a mixed flavor electron-muon pair may also be viable depending on
the propagation models. Decays to all other standard model fermions are
severely disfavored.


title: Softplus Regressions and Convex Polytopes

abstract:
  To construct flexible nonlinear predictive distributions, the paper
introduces a family of softplus function based regression models that convolve,
stack, or combine both operations by convolving countably infinite stacked
gamma distributions, whose scales depend on the covariates. Generalizing
logistic regression that uses a single hyperplane to partition the covariate
space into two halves, softplus regressions employ multiple hyperplanes to
construct a confined space, related to a single convex polytope defined by the
intersection of multiple half-spaces or a union of multiple convex polytopes,
to separate one class from the other. The gamma process is introduced to
support the convolution of countably infinite (stacked) covariate-dependent
gamma distributions. For Bayesian inference, Gibbs sampling derived via novel
data augmentation and marginalization techniques is used to deconvolve and/or
demix the highly complex nonlinear predictive distribution. Example results
demonstrate that softplus regressions provide flexible nonlinear decision
boundaries, achieving classification accuracies comparable to that of kernel
support vector machine while requiring significant less computation for
out-of-sample prediction.


title: Hard-edge asymptotics of the Jacobi growth process

abstract:
  We introduce a two parameter ($\alpha, \beta>-1$) family of interacting
particle systems with determinantal correlation kernels expressible in terms of
Jacobi polynomials $\{ P^{(\alpha, \beta)}_k \}_{k \geq 0}$. The family
includes previously discovered Plancherel measures for the infinite-dimensional
orthogonal and symplectic groups. The construction uses certain BC-type
orthogonal polynomials which generalize the characters of these groups.
  The local asymptotics near the hard edge where one expects distinguishing
behavior yields the multi-time $(\alpha, \beta)$-dependent discrete Jacobi
kernel and the multi-time $\beta$-dependent hard-edge Pearcey kernel. For
nonnegative integer values of $\beta$, the hard-edge Pearcey kernel had
previously appeared in the asymptotics of non-intersecting squared Bessel paths
at the hard edge.


title: Balloon UV Experiments for Astronomical and Atmospheric Observations

abstract:
  The ultraviolet (UV) window has been largely unexplored through balloons for
astronomy. We discuss here the development of a compact near-UV spectrograph
with fiber optics input for balloon ights. It is a modified Czerny-Turner
system built using off-the-shelf components. The system is portable and
scalable to different telescopes. The use of re ecting optics reduces the
transmission loss in the UV. It employs an image-intensified CMOS sensor,
operating in photon counting mode, as the detector of choice. A lightweight
pointing system developed for stable pointing to observe astronomical sources
is also discussed, together with the methods to improve its accuracy, e.g.
using the in-house build star sensor and others. Our primary scientific
objectives include the observation of bright Solar System objects such as
visible to eye comets, Moon and planets. Studies of planets can give us
valuable information about the planetary aurorae, helping to model and compare
atmospheres of other planets and the Earth. The other major objective is to
look at the diffuse UV atmospheric emission features (airglow lines), and at
column densities of trace gases. This UV window includes several lines
important to atmospheric chemistry, e.g. SO2, O3, HCHO, BrO. The spectrograph
enables simultaneous measurement of various trace gases, as well as provides
better accuracy at higher altitudes compared to electromechanical trace gas
measurement sondes. These lines contaminate most astronomical observations but
are poorly characterized. Other objectives may include sprites in the
atmosphere and meteor ashes from high altitude burn-outs. Our recent
experiments and observations with high-altitude balloons are discussed.


title:
Which techniques does your application use?: An information extraction
  framework for scientific articles

abstract:
  Every field of research consists of multiple application areas with various
techniques routinely used to solve problems in these wide range of application
areas. With the exponential growth in research volumes, it has become difficult
to keep track of the ever-growing number of application areas as well as the
corresponding problem solving techniques. In this paper, we consider the
computational linguistics domain and present a novel information extraction
system that automatically constructs a pool of all application areas in this
domain and appropriately links them with corresponding problem solving
techniques. Further, we categorize individual research articles based on their
application area and the techniques proposed/used in the article. k-gram based
discounting method along with handwritten rules and bootstrapped pattern
learning is employed to extract application areas. Subsequently, a language
modeling approach is proposed to characterize each article based on its
application area. Similarly, regular expressions and high-scoring noun phrases
are used for the extraction of the problem solving techniques. We propose a
greedy approach to characterize each article based on the techniques. Towards
the end, we present a table representing the most frequent techniques adopted
for a particular application area. Finally, we propose three use cases
presenting an extensive temporal analysis of the usage of techniques and
application areas.


title:
Discrete Parametric Oscillation and Nondiffracting Beams in a
  Glauber-Fock Oscillator

abstract:
  We consider a Glauber-Fock oscillator and show that diffraction can be
managed. We show how to design arrays of waveguides where light beams
experience zero diffraction. We find an exact analytical family of
nondiffracting localized solution. We predict discrete parametric oscillation
in the Glauber-Fock oscillator.


title:
Calculating branching ratio and spin-orbit coupling from
  first-principles: A formalism and its application to iridates

abstract:
  We present a simple technique to calculate spin-orbit coupling, $\langle {\bf
L}\cdot{\bf S} \rangle$, and branching ratio measured in x-ray absorption
spectroscopy. Our method is for first-principles electronic structure
calculation and its implementation is straightforward for any of standard
formulations and codes. We applied this technique to several different large
spin-orbit coupling iridates. The calculated $\langle{ {\bf L}\cdot{\bf S}}
\rangle$ and branching ratio of a prototype $j_{\rm eff}$=1/2 Mott insulator,
Sr$_2$IrO$_4$, are in good agreement with recent experimental data over the
wide range of Rh-doping. Three different double perovskite iridates (namely,
Sr$_2$MgIrO$_6$, Sr$_2$ScIrO$_6$, and Sr$_2$TiIrO$_6$) are also well described.
This technique can serve as a promising tool for studying large spin-orbit
coupling materials from first-principles and for understanding experiments.


title:
Star Clusters in the Magellanic Clouds-1: Parameterisation and
  Classification of 1072 Clusters in the LMC

abstract:
  We have introduced a semi-automated quantitative method to estimate the age
and reddening of 1072 star clusters in the Large Magellanic Cloud (LMC) using
the Optical Gravitational Lensing Experiment (OGLE) III survey data. This study
brings out 308 newly parameterised clusters. In a first of its kind, the LMC
clusters are classified into groups based on richness/mass as very poor, poor,
moderate and rich clusters, similar to the classification scheme of open
clusters in the Galaxy. A major cluster formation episode is found to happen at
125 +- 25 Myr in the inner LMC. The bar region of the LMC appears prominently
in the age range 60 - 250 Myr and is found to have a relatively higher
concentration of poor and moderate clusters. The eastern and the western ends
of the bar are found to form clusters initially, which later propagates to the
central part. We demonstrate that there is a significant difference in the
distribution of clusters as a function of mass, using a movie based on the
propagation (in space and time) of cluster formation in various groups. The
importance of including the low mass clusters in the cluster formation history
is demonstrated. The catalog with parameters, classification, and cleaned and
isochrone fitted CMDs of 1072 clusters, which are available as online material,
can be further used to understand the hierarchical formation of clusters in
selected regions of the LMC.


title:
Non-LTE line formation of Fe in late-type stars - III. 3D non-LTE
  analysis of metal-poor stars

abstract:
  As one of the most important elements in astronomy, iron abundance
determinations need to be as accurate as possible. We investigate the accuracy
of spectroscopic iron abundance analyses using archetypal metal-poor stars. We
perform detailed 3D non-LTE radiative transfer calculations based on 3D
hydrodynamic Stagger model atmospheres, and employ a new model atom that
includes new quantum-mechanical neutral hydrogen collisional rate coefficients.
With the exception of the red giant HD122563, we find that the 3D non-LTE
models achieve Fe i/Fe ii excitation and ionization balance as well as not
having any trends with equivalent width to within modelling uncertainties of
0.05 dex, all without having to invoke any microturbulent broadening; for
HD122563 we predict that the current best parallax-based surface gravity is
over-estimated by 0.5 dex. Using a 3D non-LTE analysis, we infer iron
abundances from the 3D model atmospheres that are roughly 0.1 dex higher than
corresponding abundances from 1D MARCS model atmospheres; these differences go
in the same direction as the non-LTE effects themselves. We make available
grids of departure coefficients, equivalent widths and abundance corrections,
calculated on 1D MARCS model atmospheres and horizontally- and
temporally-averaged 3D Stagger model atmospheres.


title:
Measurement of the $\tau$ lepton polarization in the decay ${\bar B}
  \rightarrow D^* \tau^- {\bar \nu_{\tau}}$

abstract:
  We report the first measurement of the $\tau$ lepton polarization in the
decay ${\bar B} \rightarrow D^* \tau^- {\bar\nu_{\tau}}$ as well as a new
measurement of the ratio of the branching fractions $R(D^{*}) =
\mathcal{B}({\bar B} \rightarrow D^* \tau^- {\bar\nu_{\tau}}) /
\mathcal{B}({\bar B} \rightarrow D^* \ell^- {\bar\nu_{\ell}})$, where $\ell^-$
denotes an electron or a muon, with the decays $\tau^- \rightarrow \pi^-
\nu_{\tau}$ and $\tau^- \rightarrow \rho^- \nu_{\tau}$. We use the full data
sample of $772 \times 10^6$ $B{\bar B}$ pairs accumulated with the Belle
detector at the KEKB electron-positron collider. Our preliminary results,
$R(D^*) = 0.276 \pm 0.034{\rm (stat.)} ^{+0.029} _{-0.026}{\rm (syst.)}$ and
$P_{\tau} = -0.44 \pm 0.47 {\rm (stat.)} ^{+0.20} _{-0.17} {\rm (syst.)}$, are
consistent with the theoretical predictions of the Standard Model within $0.6$
standard deviation.


title:
Formalization of Fault Trees in Higher-order Logic: A Deep Embedding
  Approach

abstract:
  Fault Tree (FT) is a standard failure modeling technique that has been
extensively used to predict reliability, availability and safety of many
complex engineering systems. In order to facilitate the formal analysis of FT
based analyses, a higher-order-logic formalization of FTs has been recently
proposed. However, this formalization is quite limited in terms of handling
large systems and transformation of FT models into their corresponding
Reliability Block Diagram (RBD) structures, i.e., a frequently used
transformation in reliability and availability analyses. In order to overcome
these limitations, we present a deep embedding based formalization of FTs. In
particular, the paper presents a formalization of AND, OR and NOT FT gates,
which are in turn used to formalize other commonly used FT gates, i.e., NAND,
NOR, XOR, Inhibit, Comparator and majority Voting, and the formal verification
of their failure probability expressions. For illustration purposes, we present
a formal failure analysis of a communication gateway software for the next
generation air traffic management system.


title:
Conjugate boundary condition, hidden particles, and gauge-Higgs
  inflation

abstract:
  We propose an idea that hidden particles can be separated according to gauge
quantum numbers from the visible ones by the difference of boundary conditions
on extra dimensions. We formulate 5-dimensional gauge theories yielding
conjugate boundary conditions besides ordinary ones on $S^1/Z_2$, and examine
physical implications concerning hidden particles on an extension of the
standard model coexisting different types of boundary conditions. A model with
conjugate boundary conditions is applied on a gauge-Higgs inflation scenario.


title:
$K^0 \Lambda$ and $D^- \Lambda_c^+$ production induced by pion beams off
  the nucleon

abstract:
  We present a comparative study of the pion induced production of $K^0
\Lambda$ and $D^- \Lambda_c^+$ off the nucleon. A hybrid framework is utilized
by combining an effective Lagrangian method with a Regge approach. We consider
the $t$-channel process in a plannar diagram by vector-meson Reggeon exchanges
and the $u$-channel one in a non-planar diagram by baryon Reggeon exchanges.
The present model reproduces the $K^0 \Lambda$ production data well with a few
parameters. Having fixed them, we predict the $D^- \Lambda_c^+$ production,
which turns out to be about $10^4-10^6$ times smaller than the strangeness one,
depending on the kinematical regions.


title:
Simple Modules of the Quantum Double of the Nichols Algebra of
  Unidentified Diagonal Type $\mathfrak{ufo}(7)$

abstract:
  The simple finite-dimensional modules over the Drinfeld double of the
bosonization of the Nichols algebra $\mathfrak{ufo}(7)$ are classified.


title: Theory and applications of generalized Pipek--Mezey Wannier functions

abstract:
  The theory for the generation of Wannier functions within the generalized
Pipek--Mezey approach [Lehtola, S.; J\'onsson, H. J. Chem. Theory Comput. 2014,
10, 642] is presented and an implementation thereof is described. Results are
presented for systems with periodicity in one, two and three dimensions as well
as isolated molecules. The generalized Pipek--Mezey Wannier functions (PMWF)
are highly localized orbitals consistent with chemical intuition where a
distinction is maintained between {\sigma}- and {\pi}-orbitals. The PMWF method
is compared with the so-called maximally localized Wannier functions (MLWF)
that are frequently used for the analysis of condensed matter calculations.
Whereas PMWFs maximize the localization criterion of Pipek and Mezey, MLWFs
maximize that of Foster and Boys and have the disadvantage of mixing {\sigma}-
and {\pi}-orbitals in many cases. The PMWF orbitals turn out to be as localized
as the MLWF orbitals as evidenced by cross-comparison of the values of the PMWF
and MLWF objective functions for the two types of orbitals. Our implementation
in the atomic simulation environment (ASE) is compatible with various
representations of the wave function, including real-space grids, plane waves
and linear combinations of atomic orbitals. The projector augmented wave
formalism for the representation of atomic core electrons is also supported.
Results of calculations with the GPAW software are described here, but our
implementation can also use output from other electronic structure software
such as ABINIT, NWChem and VASP.


title:
Well-posedness for the Navier-Stokes equations with datum in the Sobolev
  spaces

abstract:
  In this paper, we study local well-posedness for the Navier-Stokes \linebreak
equations with arbitrary initial data in homogeneous Sobolev spaces
$\dot{H}^s_p(\mathbb{R}^d)$ for $d \geq 2, p > \frac{d}{2},\ {\rm and}\
\frac{d}{p} - 1 \leq s < \frac{d}{2p}$. The obtained result improves the known
ones for $p > d$ and $s = 0$ M. Cannone and Y. Meyer (1995). In the case of
critical indexes $s=\frac{d}{p}-1$, we prove global well-posedness for
Navier-Stokes equations when the norm of the initial value is small enough.
This result is a generalization of the one in M. Cannone (1997) in which $p =
d$ and $s = 0$.


title: An improvement on the number of simplices in $\mathbb{F}_q^d$

abstract:
  Let $\mathcal{E}$ be a set of points in $\mathbb{F}_q^d$. Bennett, Hart,
Iosevich, Pakianathan, and Rudnev (2016) proved that if $|\mathcal{E}|\gg
q^{d-\frac{d-1}{k+1}}$ then $\mathcal{E}$ determines a positive proportion of
all $k$-simplices. In this paper, we give an improvement of this result in the
case when $\mathcal{E}$ is the Cartesian product of sets. More precisely, we
show that if $\mathcal{E}$ is the Cartesian product of sets and
$q^{\frac{kd}{k+1-1/d}}=o(|\mathcal{E}|)$, the number of congruence classes of
$k$-simplices determined by $\mathcal{E}$ is at least
$(1-o(1))q^{\binom{k+1}{2}}$, and in some cases our result is sharp.


title:
Detailed study of the column-based priority logic readout of
  Topmetal-II- CMOS pixel direct charge sensor

abstract:
  We present the detailed study of the digital readout of Topmetal-II- CMOS
pixel direct charge sensor. Topmetal-II- is an integrated sensor with an array
of 72X72 pixels each capable of directly collecting external charge through
exposed metal electrodes in the topmost metal layer. In addition to the
time-shared multiplexing readout of the analog output from Charge Sensitive
Amplifiers in each pixel, hits are also generated through comparators with
individually DAC settable thresholds in each pixel. The hits are read out via a
column-based priority logic structure, retaining both hit location and time
information. The in-array column-based priority logic is fully combinational
hence there is no clock distributed in the pixel array. Sequential logic and
clock are placed on the peripheral of the array. We studied the detailed
working behavior and performance of this readout, and demonstrated its
potential in imaging applications.


title: A special case of quasiminimality

abstract:
  We deduce a special case of Zilber's quasiminimality conjecture, for the
complex exponential field, from work of Henson and Rubel. Specifically, we deal
with those subsets of $\mathbb{C}$ defined by formulas of the form
$\exists\bar{y}(P(x,\bar{y})=0)$, where $P$ is a term formed from the language
$\{+,\times,\exp\}$ together with parameters from $\mathbb{C}$.


title: Distinct distances on regular varieties over finite fields

abstract:
  In this paper we study some generalized versions of a recent result due to
Covert, Koh, and Pi (2015). More precisely, we prove that if a subset
$\mathcal{E}$ in a regular variety satisfies $|\mathcal{E}|\gg
q^{\frac{d-1}{2}+\frac{1}{k-1}}$, then $\Delta_{k, F}(\mathcal{E})\supseteq
\mathbb{F}_q\setminus \{0\}$ for some certain families of polynomials
$F(\mathbf{x})\in \mathbb{F}_q[x_1, \ldots, x_d]$.


title:
Analyticity Properties and Asymptotic Behavior of Scattering Amplitude
  in Higher Dimensional Theories

abstract:
  The properties of the high energy behavior of the scattering amplitude of
massive, neutral and spinless particles in higher dimensional field theories
are investigated. The axiomatic formulation of Lehmann, Symanzik and Zimmermann
is adopted. The analyticity properties of the causal, the retarded and the
advanced functions associated with the four point elastic amplitudes are
studied. The analog of the Lehmann-Jost-Dyson representation is obtained in
higher dimensional field theories. The generalized J-L-D representation is
utilized to derive the t-plane analyticity property of the amplitude. The
existence of an ellipse analogous to the Lehmann ellipse is demonstrated. Thus
a fixed-t dispersion relation can be written down with finite number of
subtractions due to the temperedness of the amplitudes. The domain of
analyticity of scattering amplitude in $s$ and $t$ variables is extended by
imposing unitarity constraints. A generalized version of Martin's theorem is
derived to prove the existence of such a domain in D-dimensional field
theories. It is shown that the amplitude can be expanded in a power series in t
which converges for |t|<R; R being s-independent. The positivity properties of
absorptive amplitudes are derived to prove the $t$-plane analyticity of
amplitude. In the extended analyticity domain dispersion relations are written
with two subtractions. The bound on the total cross section is derived from LSZ
axioms without any extra ad hoc assumptions.


title:
Phased Exploration with Greedy Exploitation in Stochastic Combinatorial
  Partial Monitoring Games

abstract:
  Partial monitoring games are repeated games where the learner receives
feedback that might be different from adversary's move or even the reward
gained by the learner. Recently, a general model of combinatorial partial
monitoring (CPM) games was proposed \cite{lincombinatorial2014}, where the
learner's action space can be exponentially large and adversary samples its
moves from a bounded, continuous space, according to a fixed distribution. The
paper gave a confidence bound based algorithm (GCB) that achieves
$O(T^{2/3}\log T)$ distribution independent and $O(\log T)$ distribution
dependent regret bounds. The implementation of their algorithm depends on two
separate offline oracles and the distribution dependent regret additionally
requires existence of a unique optimal action for the learner. Adopting their
CPM model, our first contribution is a Phased Exploration with Greedy
Exploitation (PEGE) algorithmic framework for the problem. Different algorithms
within the framework achieve $O(T^{2/3}\sqrt{\log T})$ distribution independent
and $O(\log^2 T)$ distribution dependent regret respectively. Crucially, our
framework needs only the simpler "argmax" oracle from GCB and the distribution
dependent regret does not require existence of a unique optimal action. Our
second contribution is another algorithm, PEGE2, which combines gap estimation
with a PEGE algorithm, to achieve an $O(\log T)$ regret bound, matching the GCB
guarantee but removing the dependence on size of the learner's action space.
However, like GCB, PEGE2 requires access to both offline oracles and the
existence of a unique optimal action. Finally, we discuss how our algorithm can
be efficiently applied to a CPM problem of practical interest: namely, online
ranking with feedback at the top.


title: Polynomials and Second Order Linear Recurrences

abstract:
  One of the most interesting results of the last century was the proof
completed by Matijasevich that computably enumerable sets are precisely the
diophantine sets [MRDP Theorem, 9], thus settling, based on previously
developed machinery, Hilbert's question whether there exists a general
algorithm for checking the solvability in integers of any diophantine equation.
In this paper we describe techniques to prove the nonexistence of polynomials
in two variables for some simple generalizations of the Fibonacci sequence
(explicit diophantine representation of Fibonacci numbers were known from
Jones' polynomial whose positive values have the same range as that of
Fibonacci numbers), and we believe similar techniques exist for the primes. In
this paper we mainly show the following results: (1) using one of the many
techniques known for solving the Pell's equation, namely the solution in an
extended number system, we prove the existence and explicitly find the
polynomials for the recurrences of the form $e(n)=ae(n-1)+e(n-2)$ with starting
values of 0 and 1 in particular, and for any arbitrary starting values, in the
process defining a concept of fundamental starting numbers, (2) we prove a few
identities that seem to be quite interesting and useful, (3) we use these
identities in a novel way to generate systems of equations of certain rank
deficiency using which we disprove for the first time the existence of any
polynomial in 2 variables for the generalized recurrence of the form
$e(n)=ae(n-1)+be(n-2)$


title:
Multi-Pair Two-Way Relay Network with Harvest-Then-Transmit Users:
  Resolving Pairwise Uplink-Downlink Coupling

abstract:
  While two-way relaying is a promising way to enhance the spectral efficiency
of wireless networks, the imbalance of relay-user distances may lead to
excessive wireless power at the nearby-users. To exploit the excessive power,
the recently proposed harvest-then-transmit technique can be applied. However,
it is well-known that harvest-then-transmit introduces uplink-downlink coupling
for a user. Together with the co-dependent relationship between paired users
and interference among multiple user pairs, wirelessly powered two-way relay
network suffers from the unique pairwise uplink-downlink coupling, and the
joint uplink-downlink network design is nontrivial. To this end, for the one
pair users case, we show that a global optimal solution can be obtained. For
the general case of multi-pair users, based on the rank-constrained difference
of convex program, a convergence guaranteed iterative algorithm with an
efficient initialization is proposed. Furthermore, a lower bound to the
performance of the optimal solution is derived by introducing virtual receivers
at relay. Numerical results on total transmit power show that the proposed
algorithm achieves a transmit power value close to the lower bound.


title: Resonances in axially symmetric dielectric objects

abstract:
  A high-order convergent and robust numerical solver is constructed and used
to find complex eigenwavenumbers and electromagnetic eigenfields of dielectric
objects with axial symmetry. The solver is based on Fourier--Nystr\"om
discretization of combined integral equations for the transmission problem and
can be applied to demanding resonance problems at microwave, terahertz, and
optical wavelengths. High achievable accuracy, even at very high wavenumbers,
makes the solver ideal for benchmarking and for assessing the performance of
general purpose commercial software.


title: A realization theorem for sets of distances

abstract:
  Let $H$ be an atomic monoid. The set of distances $\Delta (H)$ of $H$ is the
set of all $d \in \mathbb{N}$ with the following property: there are
irreducible elements $u\_1, \ldots, u\_k, v\_1 \ldots, v\_{k+d}$ such that
$u\_1 \cdot \ldots \cdot u\_k=v\_1 \cdot \ldots \cdot v\_{k+d}$ but $u\_1 \cdot
\ldots \cdot u\_k$ cannot be written as a product of $\ell$ irreducible
elements for any $\ell \in \mathbb{N}$ with $k\lt \ell \lt k+d$. It is
well-known (and easy to show) that, if $\Delta (H)$ is nonempty, then $\min
\Delta (H) = \gcd \Delta (H)$. In this paper we show conversely that for every
finite nonempty set $\Delta \subset \mathbb{N}$ with $\min \Delta = \gcd
\Delta$ there is a finitely generated Krull monoid $H$ such that $\Delta
(H)=\Delta$.


title: Online Learning to Rank with Top-k Feedback

abstract:
  We consider two settings of online learning to rank where feedback is
restricted to top ranked items. The problem is cast as an online game between a
learner and sequence of users, over $T$ rounds. In both settings, the learners
objective is to present ranked list of items to the users. The learner's
performance is judged on the entire ranked list and true relevances of the
items. However, the learner receives highly restricted feedback at end of each
round, in form of relevances of only the top $k$ ranked items, where $k \ll m$.
The first setting is \emph{non-contextual}, where the list of items to be
ranked is fixed. The second setting is \emph{contextual}, where lists of items
vary, in form of traditional query-document lists. No stochastic assumption is
made on the generation process of relevances of items and contexts. We provide
efficient ranking strategies for both the settings. The strategies achieve
$O(T^{2/3})$ regret, where regret is based on popular ranking measures in first
setting and ranking surrogates in second setting. We also provide impossibility
results for certain ranking measures and a certain class of surrogates, when
feedback is restricted to the top ranked item, i.e. $k=1$. We empirically
demonstrate the performance of our algorithms on simulated and real world
datasets.


title:
Learning to Communicate: Channel Auto-encoders, Domain Specific
  Regularizers, and Attention

abstract:
  We address the problem of learning efficient and adaptive ways to communicate
binary information over an impaired channel. We treat the problem as
reconstruction optimization through impairment layers in a channel autoencoder
and introduce several new domain-specific regularizing layers to emulate common
channel impairments. We also apply a radio transformer network based attention
model on the input of the decoder to help recover canonical signal
representations. We demonstrate some promising initial capacity results from
this architecture and address several remaining challenges before such a system
could become practical.


title:
High-performance electronic cooling with superconducting tunnel
  junctions

abstract:
  When biased at a voltage just below a superconductor's energy gap, a tunnel
junction between this superconductor and a normal metal cools the latter. While
the study of such devices has long been focussed to structures of submicron
size and consequently cooling power in the picoWatt range, we have led a
thorough study of devices with a large cooling power up to the nanoWatt range.
Here we describe how their performance can be optimized by using a
quasi-particle drain and tuning the cooling junctions' tunnel barrier.


title:
Density-Matrix Renormalization Group study of Many-Body Localization in
  Floquet Eigenstates

abstract:
  We generalize the recently introduced Density-Matrix Renormalization Group
(DMRG-X) [Khemani et al, PRL 2016] algorithm to obtain Floquet eigenstates of
one-dimensional, periodically driven many-body localized systems. This
generalization is made possible by the fact that the time-evolution operator
for a period can be efficiently represented using a matrix-product operator. We
first benchmark the method by comparing to exact diagonalization for small
systems. We then obtain Floquet eigenstates for larger systems and show
unambiguously that the characteristic area-law scaling remains robust.


title: Stability revisited: new generalisation bounds for the Leave-one-Out

abstract:
  The present paper provides a new generic strategy leading to non-asymptotic
theoretical guarantees on the Leave-one-Out procedure applied to a broad class
of learning algorithms. This strategy relies on two main ingredients: the new
notion of $L^q$ stability, and the strong use of moment inequalities. $L^q$
stability extends the ongoing notion of hypothesis stability while remaining
weaker than the uniform stability. It leads to new PAC exponential
generalisation bounds for Leave-one-Out under mild assumptions. In the
literature, such bounds are available only for uniform stable algorithms under
boundedness for instance. Our generic strategy is applied to the Ridge
regression algorithm as a first step.


title:
Generalized monogamy inequalities of convex-roof extended negativity in
  $N$-qubit systems

abstract:
  In this paper, we present some generalized monogamy inequalities based on
negativity and convex-roof extended negativity (CREN). These monogamy relations
are satisfied by the negativity of $N$-qubit quantum systems $ABC_1\cdots
C_{N-2}$, under the partitions $AB|C_1\cdots C_{N-2}$ and $ABC_1|C_2\cdots
C_{N-2}$. Furthermore, the $W$-class states are used to test these generalized
monogamy inequalities.


title:
Observation of dynamics of hydrogen bonds in TGS crystals by means of
  measurements of pyroelectric currents induced by changes of temperature

abstract:
  The study of pyroelectric response of monocrystalline TGS cubic specimens to
changes of temperature induced by linear and pulse heating of three mutually
perpendicular pairs of cube sides demonstrated a complicated structure of
signals. We attribute their forms to the activation of various hydrogen bonds
between glycine I, II, III molecules. In the case of pulse heating the
pyroelectric signal is observed also in the paraelectric phase. The applied
measurement method is relatively simple but precise and can be realized in most
of dielectric measurements laboratories.


title: Online bin packing with cardinality constraints resolved

abstract:
  Cardinality constrained bin packing or bin packing with cardinality
constraints is a basic bin packing problem. In the online version with the
parameter k \geq 2, items having sizes in (0,1] associated with them are
presented one by one to be packed into unit capacity bins, such that the
capacities of bins are not exceeded, and no bin receives more than k items. We
resolve the online problem in the sense that we prove a lower bound of 2 on the
overall asymptotic competitive ratio. This closes this long standing open
problem, since an algorithm of an absolute competitive ratio 2 is known.
Additionally, we significantly improve the known lower bounds on the asymptotic
competitive ratio for every specific value of k. The novelty of our
constructions is based on full adaptivity that creates large gaps between item
sizes. Thus, our lower bound inputs do not follow the common practice for
online bin packing problems of having a known in advance input consisting of
batches for which the algorithm needs to be competitive on every prefix of the
input.


title:
RELARM: A rating model based on relative PCA attributes and k-means
  clustering

abstract:
  Following widely used in visual recognition concept of relative attributes,
the article establishes definition of the relative PCA attributes for a class
of objects defined by vectors of their parameters. A new rating model (RELARM)
is built using relative PCA attribute ranking functions for rating object
description and k-means clustering algorithm. Rating assignment of each rating
object to a rating category is derived as a result of cluster centers
projection on the specially selected rating vector. Empirical study has shown a
high level of approximation to the existing S & P, Moody's and Fitch ratings.


title:
Geometric Interpretation of Theoretical Bounds for RSS-based Source
  Localization with Uncertain Anchor Positions

abstract:
  The Received Signal Strength based source localization can encounter severe
problems originating from uncertain information about the anchor positions in
practice. The anchor positions, although commonly assumed to be precisely known
prior to the source localization, are usually obtained using previous
estimation algorithm such as GPS. This previous estimation procedure produces
anchor positions with limited accuracy that result in degradations of the
source localization algorithm and topology uncertainty. We have recently
addressed the problem with a joint estimation framework that jointly estimates
the unknown source and uncertain anchors positions and derived the theoretical
limits of the framework. This paper extends the authors previous work on the
theoretical performance bounds of the joint localization framework with
appropriate geometric interpretation of the overall problem exploiting the
properties of semi-definiteness and symmetry of the Fisher Information Matrix
and the Cram{\`e}r-Rao Lower Bound and using Information and Error Ellipses,
respectively. The numerical results aim to illustrate and discuss the
usefulness of the geometric interpretation. They provide in-depth insight into
the geometrical properties of the joint localization problem underlining the
various possibilities for practical design of efficient localization
algorithms.


title:
Finest light curve details, physical parameters, and period fluctuations
  of CoRoT RR Lyrae stars

abstract:
  The CoRoT satellite supplied the scientific community with a huge data base
of variable stars. Among them the RR Lyrae stars have intensively been
discussed in numerous papers in the last few years, but the latest runs have
not been checked to find RR Lyrae stars up to now. Our main goal was to fill
this gap and complete the CoRoT RR Lyrae sample. We found nine unstudied RR
Lyrae stars. Seven of them are new discoveries. We identified three new Blazhko
stars. The Blazhko effect shows non-strictly repetitive nature for all stars.
The frequency spectrum of the Blazhko star CoRoT 104948132 contains second
overtone frequency with the highest known period ratio. The harmonic amplitude
and phase declines with the harmonic order were studied for non-Blazhko stars.
We found a period dependent but similar shape amplitude decline for all stars.
We discovered significant random period fluctuation for one of the two
oversampled target, CM Ori. After a successful transformation of the CoRoT band
parameters to the Johnson V values we estimated the basic physical properties
such as mass, luminosity, metallicity. The sample can be divided into two
subgroups with respect to the metallicity but otherwise the physical parameters
are in the canonical range of RR Lyrae stars.


title:
An alternative approach to the limits of predictability in human
  mobility

abstract:
  Next place prediction algorithms are invaluable tools, capable of increasing
the efficiency of a wide variety of tasks, ranging from reducing the spreading
of diseases to better resource management in areas such as urban planning. In
this work we estimate upper and lower limits on the predictability of human
mobility to help assess the performance of competing algorithms. We do this
using GPS traces from 604 individuals participating in a multi year long
experiment, The Copenhagen Networks study. Earlier works, focusing on the
prediction of a participant's whereabouts in the next time bin, have found very
high upper limits (>90%). We show that these upper limits are highly dependent
on the choice of a spatiotemporal scales and mostly reflect stationarity, i.e.
the fact that people tend to not move during small changes in time. This leads
us to propose an alternative approach, which aims to predict the next location,
rather than the location in the next bin. Our approach is independent of the
temporal scale and introduces a natural length scale. By removing the effects
of stationarity we show that the predictability of the next location is
significantly lower (~71%) than the predictability of the location in the next
bin.


title:
A Harmonic Potential Field Approach for Joint Planning & Control of a
  Rigid, Separable Nonholonomic, Mobile Robot

abstract:
  The main objective of this paper is to provide a tool for performing path
planning at the servo level of a mobile robot. The ability to perform, in a
provably correct manner, such a complex task at the servo level can lead to a
large increase in the speed of operation, low energy consumption and high
quality of response. Planning has been traditionally limited to the high level
controller of a robot. The guidance velocity signal from this stage is usually
converted to a control signal using what is known as an electronic speed
controller (ESC). This paper demonstrates the ability of the harmonic potential
field (HPF) approach to generate a provably correct, constrained, well behaved
trajectory and control signal for a rigid, nonholonomic robot in a stationary,
cluttered environment. It is shown that the HPF based, servo level planner can
address a large number of challenges facing planning in a realistic situation.
The suggested approach migrates the rich and provably correct properties of the
solution trajectories from an HPF planner to those of the robot. This is
achieved using a synchronizing control signal whose aim is to align the
velocity of the robot in its local coordinates, with that of the gradient of
the HPF. The link between the two is made possible by representing the robot
using what the paper terms separable form. The context-sensitive and
goal-oriented control signal used to steer the robot is demonstrated to be well
behaved and robust in the presence of actuator noise, saturation and
uncertainty in the parameters. The approach is developed, proofs of correctness
are provided and the capabilities of the scheme are demonstrated using
simulation results.


title: Some examples of rank-2 Brill-Noether loci

abstract:
  In this paper, we construct some examples of rank-2 Brill-Noether loci with
"unexpected" properties on general curves. The key example is in genus 6, but
we also have interesting examples in rank 5 and in higher genus. We relate some
of our results to the recent proof of Mercat's conjecture in rank 2 by Bakker
and Farkas.


title:
Schur Method for Robust Pole Assignment of Descriptor Systems via
  Proportional Plus Derivative State Feedback

abstract:
  The pole assignment problem for descriptor systems is a classical inverse
algebraic eigenvalue problem, which has attracted attention for decades. In
this paper, we propose a direct method to solve the problem with the
application of the proportional plus derivative state feedback, intending to
obtain a robust closed-loop system. Theorems on the feasibility of our method
will be presented. Numerical examples show that our method yields poles of high
relative accuracy.


title: Numerical modular symbols for elliptic curves

abstract:
  We present a detailed analysis of how to implement the computation of modular
symbols for a given elliptic curve by using numerical approximations. This
method turns out to be more efficient than current implementation as the
conductor of the curve increases.


title:
Global well-posedness of the two-dimensional exterior Navier-Stokes
  equations for non-decaying data

abstract:
  We prove global well-posedness of the two-dimensional exterior Navier-Stokes
equations for bounded initial data with a finite Dirichlet integral, subject to
the non-slip boundary condition. As an application, we construct global
solutions for asymptotically constant initial data and arbitrary large Reynolds
numbers.


title: Status and developments of event generators

abstract:
  Event generators play a crucial role in the exploration of LHC physics. This
presentation summarizes news and plans for the three general-purpose pp
generators HERWIG, PYTHIA and SHERPA, as well as briefer notes on a few other
generators. Common themes, such as the matching and merging between matrix
elements and parton showers, are highlighted. Other topics include a historical
introduction, from the Lund perspective, and comments on the role of MCnet.


title: On fundamental groups of tensor product $\rm II_1$ factors

abstract:
  Let $M$ be a $\rm II_1$ factor and let $\mathcal{F}(M)$ denote the
fundamental group of $M$. In this article, we study the following property of
$M$: for arbitrary $\rm II_1$ factor $B$, we have $\mathcal{F}(M
\overline{\otimes} B)=\mathcal{F}(M)\mathcal{F}(B)$. We prove that for any
subgroup $G\leq \mathbb{R}^*_+$ which is realized as a fundamental group of a
$\rm II_1$ factor, there exists a $\rm II_1$ factor $M$ which satisfies this
property and whose fundamental group is $G$. Using this, we deduce that if $G,H
\leq \mathbb{R}^*_+$ are realized as fundamental groups of $\rm II_1$ factors
(with separable predual), then so are groups $G \cdot H$ and $G \cap H$.


title: Arbitrarily regularizable graphs

abstract:
  A graph is regularizable if it is possible to assign weights to its edges so
that all nodes have the same degree. Weights can be positive, nonnegative or
arbitrary as soon as the regularization degree is not null. Positive and
nonnegative regularizable graphs have been thoroughly investigated in the
literature. In this work, we propose and study arbitrarily regularizable
graphs. In particular, we investigate necessary and sufficient regularization
conditions on the topology of the graph and of the corresponding adjacency
matrix. Moreover, we study the computational complexity of the regularization
problem and characterize it as a linear programming model.


title: The sub-leading coefficient of the L-function of an elliptic curve

abstract:
  In this very short note, we show that there is a relation between the leading
term at $s=1$ of an $L$-function of an elliptic curve defined over an number
field and the term that follows.


title:
The Swift-BAT monitoring reveals a long term decay of the cyclotron line
  energy in Vela X-1

abstract:
  We study the behaviour of the cyclotron resonant scattering feature (CRSF) of
the high mass X-ray binary Vela X-1 using the long-term hard X-ray monitoring
performed by the Burst Alert Telescope (BAT) on board Swift. High statistics,
intensity selected spectra were built along 11 years of BAT survey. While the
fundamental line is not revealed, the second harmonic of the CRSF can be
clearly detected in all the spectra, at an energy varying between $\sim 53$ keV
and $\sim 58$ keV, directly correlated with the luminosity. We have further
investigated the evolution of the CRSF in time, by studying the intensity
selected spectra built along four 33-month time intervals along the survey. For
the first time we find in this source a secular variation in the CRSF energy:
independent of the source luminosity, the CRSF second harmonic energy decreases
by $\sim 0.36$ keV/year between the first and the third time interval,
corresponding to an apparent decay of the magnetic field of $\sim 3\times
10^{10}$ G/year. The intensity-cyclotron energy pattern is consistent between
the third and the last time intervals. A possible interpretation for this decay
could be the settling of an accreted mound that produces either a distortion of
the poloidal magnetic field on the polar cap or a geometrical displacement of
the line forming region. This hypothesis seems supported by the correspondance
between the rate of the line shift per unit accreted mass and the mass accreted
on the polar cap per unit area in Vela X-1 and Her X-1, respectively.


title:
Self-organized Growth of Graphene Nanomesh with Increased Gas
  Sensitivity

abstract:
  A bottom-up chemical vapor deposition (CVD) process for the growth of
graphene nanomesh films is demonstrated. The process relies on silicon
nanospheres to block nucleation sites for graphene CVD on copper substrates.
These spheres are formed in a self-organized way through silicon diffusion
through a 5 $\mu$m copper layer on a silicon wafer coated with 400 nm of
silicon nitride. The temperature during the growth process disintegrates the
$Si_3$$N_4$ layer and silicon atoms diffuse to the copper surface, where they
form the nanospheres. After graphene nanomesh growth, the Si nanospheres can be
removed by a simple hydrofluoric acid etch, leaving holes in the graphene film.
The nanomesh films have been successfully transferred to different substrates,
including gas sensor test structures, and verified and characterized by Auger,
TEM and SEM measurements. Electrical/gas-exposure measurements show a 2-fold
increase in ammonia sensitivity compared to plain graphene sensors. This
improvement can be explained by a higher adsorption site density (edge sites).
This new method for nanopatterned graphene is scalable, inexpensive and can be
carried out in standard semiconductor industry equipment. Furthermore, the
substrates are reusable.


title: On the subRiemannian cut locus in a model of free two-step Carnot group

abstract:
  We characterize the subRiemannian cut locus of the origin in the free Carnot
group of step two with three generators. We also calculate explicitly the cut
time of any extremal path and the distance from the origin of all points of the
cut locus. Finally, by using the Hamiltonian approach, we show that the cut
time of strictly normal extremal paths is a smooth explicit function of the
initial velocity covector. Finally, using our previous results, we show that at
any cut point the distance has a corner-like singularity.


title: Mean Field Limit and Propagation of Chaos for a Pedestrian Flow Model

abstract:
  In this paper a rigorous proof of the mean field limit for a pedestrian flow
model in two dimensions is given by using a probabilistic method.
  The model under investigation is an interacting particle system coupled to
the eikonal equation on the microscopic scale.
  For stochastic initial data, it is proved that the solution of the
$N$-particle pedestrian flow system with properly chosen cut-off converges in
the probability sense to the solution of the characteristics of the non-cut-off
Vlasov equation.
  Furthermore, the result on propagation of chaos is also deduced in terms of
bounded Lipschitz distance.


title:
Molecular Dynamics Simulations of Chemically Disordered Ferroelectric
  (Ba,Sr)TiO$_3$ with a Semi-Empirical Effective Hamiltonian

abstract:
  We present a semi-empirical effective Hamiltonian to capture effects of
disorder associated with Ba and Sr cations occupying $A$ sites in
(Ba$_{x}$Sr$_{1-x}$)TiO$_3$ on its ferroelectric phase transition. Averaging
between the parameters of first-principles effective Hamiltonians of end
members BaTiO$_3$ and SrTiO$_3$, we include a term with an empirical parameter
to capture the local polarization and strains arising from the difference
between ionic radii of Ba and Sr. Using mixed-space molecular dynamics of the
effective Hamiltonian, we determine $T$-dependent ferroelectric phase
transitions in (Ba$_{x}$Sr$_{1-x}$)TiO$_3$ which are in good agreement with
experiment. Our scheme of determination of semi-empirical parameters in
effective Hamiltonian should be applicable to other perovskite-type
ferroelectric solid solutions.


title:
Convolutional Network for Attribute-driven and Identity-preserving Human
  Face Generation

abstract:
  This paper focuses on the problem of generating human face pictures from
specific attributes. The existing CNN-based face generation models, however,
either ignore the identity of the generated face or fail to preserve the
identity of the reference face image. Here we address this problem from the
view of optimization, and suggest an optimization model to generate human face
with the given attributes while keeping the identity of the reference image.
The attributes can be obtained from the attribute-guided image or by tuning the
attribute features of the reference image. With the deep convolutional network
"VGG-Face", the loss is defined on the convolutional feature maps. We then
apply the gradient decent algorithm to solve this optimization problem. The
results validate the effectiveness of our method for attribute driven and
identity-preserving face generation.


title: Paradox of integration -- a computational model

abstract:
  The paradoxical aspect of integration of a social group has been highlighted
by Peter Blau (Exchange and Power in Social Life, Wiley and Sons, 1964). During
the integration process, the group members simultaneously compete for social
status and play the role of the audience. Here we show that when the
competition prevails over the desire of approval, a sharp transition breaks all
friendly relations. However, as was described by Blau, people with high status
are inclined to bother more with acceptance of others; this is achieved by
praising others and revealing her/his own weak points. In our model, this
action smooths the transition and improves interpersonal relations.


title:
Dynamic dependence to domain wall propagation through artificial spin
  ice

abstract:
  Domain wall propagation dynamics have been studied in nanostructured
artificial kagome spin ice structures. A stripline circuit has been used to
provide localised pulsed magnetic fields within the artificial spin ice
structure. This provides control of the system through electrically assisted
domain wall nucleation events. Synchronisation of the pulsed fields with
additional global magnetic fields and the use of a focussed magneto-optical
Kerr effect magnetometer allows our experiments to probe the domain wall
transit through an extended ASI structure. We find that the propagation
distance depends on the driving field revealing field driven properties of
domain walls below their intrinsic nucleation field.


title:
Quasiparticle interference from different impurities on the surface of
  pyrochlore iridates: signatures of the Weyl phase

abstract:
  Weyl semimetals are gapless three-dimensional topological materials where two
bands touch at an even number of points in the bulk Brillouin zone. These
semimetals exhibit topologically protected surface Fermi arcs, which pairwise
connect the projected bulk band touchings in the surface Brillouin zone. Here,
we analyze the quasiparticle interference patterns of the Weyl phase when
time-reversal symmetry is explicitly broken. We use a multi-band $d$-electron
Hubbard Hamiltonian on a pyrochlore lattice, relevant for the pyrochlore
iridate R$_2$Ir$_2$O$_7$ (where R is a rare earth). Using exact
diagonalization, we compute the surface spectrum and quasiparticle interference
(QPI) patterns for various surface terminations and impurities. We show that
the spin and orbital texture of the surface states can be inferred from the
absence of certain backscattering processes and from the symmetries of the QPI
features for non-magnetic and magnetic impurities. Furthermore, we show that
the QPI patterns of the Weyl phase in pyrochlore iridates may exhibit
additional interesting features that go beyond those found previously in TaAs.


title: Hopf hypersurfaces in spaces of oriented geodesics

abstract:
  A Hopf hypersurface in a (para-)Kaehler manifold is a real hypersurface for
which one of the principal directions of the second fundamental form is the
(para-)complex dual of the normal vector.
  We consider particular Hopf hypersurfaces in the space of oriented geodesics
of a non-flat space form of dimension greater than 2. For spherical and
hyperbolic space forms, the oriented geodesic space admits a canonical
Kaehler-Einstein and para-Kaehler-Einstein structure, respectively, so that a
natural notion of a Hopf hypersurface exists.
  The particular hypersurfaces considered are formed by the oriented geodesics
that are tangent to a given convex hypersurface in the underlying space form.
We prove that a tangent hypersurface is Hopf in the space of oriented geodesics
with respect to this canonical (para-)Kaehler structure iff the underlying
convex hypersurface is totally umbilic and non-flat.
  In the case of 3 dimensional space forms, however, there exists a second
canonical complex structure which can also be used to define Hopf
hypersurfaces. We prove that in this dimension, the tangent hypersurface of a
convex hypersurface in the space form is always Hopf with respect to this
second complex structure.


title: An Ultraviolet imager to study bright UV sources

abstract:
  We have designed and developed a compact ultraviolet imaging payload to fly
on a range of possible platforms such as high altitude balloon experiments,
cubesats, space missions, etc. The primary science goals are to study the
bright UV sources (mag < 10) and also to look for transients in the Near UV
(200 - 300 nm) domain. Our first choice is to place this instrument on a
spacecraft going to the Moon as part of the Indian entry into Google lunar
X-Prize competition. The major constraints for the instrument are, it should be
lightweight (< 2Kg), compact (length < 50cm) and cost effective. The instrument
is an 80 mm diameter Cassegrain telescope with a field of view of around half a
degree designated for UV imaging. In this paper we will discuss about the
various science cases that can be performed by having observations with the
instrument on different platforms. We will also describe the design,
development and the current state of implementation of the instrument. This
includes opto-mechanical and electrical design of the instrument. We have
adopted an all spherical optical design which would make the system less
complex to realize and a cost effective solution compared to other telescope
configuration. The structural design has been chosen in such a way that it will
ensure that the instrument could withstand all the launch load vibrations. An
FPGA based electronics board is used for the data acquisition, processing and
CCD control. We will also briefly discuss about the hardware implementation of
the detector interface and algorithms for the detector readout and data
processing.


title:
A Delay-Tolerant Potential-Field-Based Network Implementation of an
  Integrated Navigation System

abstract:
  Network controllers (NCs) are devices that are capable of converting dynamic,
spatially extended, and functionally specialized modules into a taskable
goal-oriented group called networked control system. This paper examines the
practical aspects of designing and building an NC that uses the Internet as a
communication medium. It focuses on finding compatible controller components
that can be integrated via a host structure in a manner that makes it possible
to network, in real-time, a webcam, an unmanned ground vehicle (UGV), and a
remote computer server along with the necessary operator software interface.
The aim is to deskill the UGV navigation process and yet maintain a robust
performance. The structure of the suggested controller, its components, and the
manner in which they are interfaced are described. Thorough experimental
results along with performance assessment and comparisons to a previously
implemented NC are provided.


title: Feynman Propagators on Static Spacetimes

abstract:
  We consider the Klein-Gordon equation on a static spacetime and minimally
coupled to a static electromagnetic potential. We show that it is essentially
self-adjoint on $C_{\mathrm{c}}^\infty$. We discuss various distinguished
inverses and bisolutions of the Klein-Gordon operator, focusing on the
so-called Feynman propagator. We show that the Feynman propagator can be
considered the boundary value of the resolvent of the Klein-Gordon operator, in
the spirit of the limiting absorption principle known from the theory of
Schr\"odinger operators. We also show that the Feynman propagator is the limit
of the inverse of the Wick rotated Klein-Gordon operator.


title: Quenched large deviations for interacting diffusions in random media

abstract:
  The aim of the paper is to establish a large deviation principle (LDP) for
the empirical measure of mean-field interacting diffusions in a random
environment. The point is to derive such a result once the environment has been
frozen (quenched model). The main theorem states that a LDP holds for every
realization of the environment, with a rate function that does not depend on
the disorder and is different from the rate function in the averaged model.
Similar results concerning the empirical flow and local empirical measures are
provided.


title: Efficient single photon absorption by a trapped moving atom

abstract:
  The influence of the center of mass motion of a trapped two level system on
efficient resonant single photon absorption is investigated. It is shown that
this absorption process depends strongly on the ratio between the
characteristic time scales of spontaneous photon emission and of the two level
system's center of mass motion. In particular, if the spontaneous photon
emission process occurs almost instantaneously on the time scale of the center
of mass motion coherent control of the center of mass motion offers interesting
perspectives for optimizing single photon absorption. It is demonstrated that
this way time dependent modulation of a harmonic trapping frequency allows to
squeeze the two level system's center of mass motion so strongly that high
efficient single photon absorption is possible even in cases of weak
confinement by a trapping potential.


title:
General model of depolarization and transfer of polarization of singly
  ionized atoms by collisions with hydrogen atoms

abstract:
  Simulations of the generation of the atomic polarization is necessary for
interpreting the second solar spectrum. For this purpose, it is important to
rigorously determine the effects of the isotropic collisions with neutral
hydrogen on the atomic polarization of the neutral atoms, ionized atoms and
molecules. Our aim is to treat in generality the problem of depolarizing
isotropic collisions between singly ionized atoms and neutral hydrogen in its
ground state. Using our numerical code, we computed the collisional
depolarization rates of the $p$-levels of ions for large number of values of
the effective principal quantum number $n^{*}$ and the Uns\"old energy $E_p$.
Then, genetic programming has been utilized to fit the available depolarization
rates. As a result, strongly non-linear relationships between the collisional
depolarization rates, $n^{*}$ and $E_p$ are obtained, and are shown to
reproduce the original data with accuracy clearly better than 10\%. These
relationships allow quick calculations of the depolarizing collisional rates of
any simple ion which is very useful for the solar physics community. In
addition, the depolarization rates associated to the complex ions and to the
hyperfine levels can be easily derived from our results. In this work we have
shown that by using powerful numerical approach and our collisional method,
general model giving the depolarization of the ions can be obtained to be
exploited for solar applications.


title:
The effect of spin-orbit coupling on the effective-spin correlation in
  YbMgGaO4

abstract:
  Motivated by the recent experiments on the triangular lattice spin liquid
YbMgGaO$_4$, we explore the effect of spin-orbit coupling on the effective-spin
correlation of the Yb local moments. We point out the anisotropic interaction
between the effective-spins on the nearest neighbor bonds is sufficient to
reproduce the spin-wave dispersion of the fully polarized state in the presence
of strong magnetic field normal to the triangular plane. We further evaluate
the effective-spin correlation within the mean-field spherical approximation.
We explicitly demonstrate that, the nearest-neighbor anisotropic effective-spin
interaction, originating from the strong spin-orbit coupling, enhances the
effective-spin correlation at the M points in the Brillouin zone. We identify
these results as the strong evidence for the anisotropic interaction and the
strong spin-orbit coupling in YbMgGaO$_4$.


title:
Evolution of Intermittency in the Slow and Fast Solar Wind Beyond the
  Ecliptic Plane

abstract:
  We study intermittency as a departure from self-similarity of the solar wind
magnetic turbulence and investigate the evolution with the heliocentric
distance and latitude. We use data from the Ulysses spacecraft measured during
two solar minima (1997-1998 and 2007-2008) and one solar maximum (1999-2001).
In particular, by modeling a multifractal spectrum, we revealed the
intermittent character of turbulence in the small-scale fluctuations of the
magnetic field embedded in the slow and fast solar wind. Generally, at small
distances from the Sun, in both the slow and fast solar wind, we observe the
high degree of multifractality (intermittency) that decreases somewhat slowly
with distance and slowly with latitude. The obtained results seem to suggest
that generally intermittency in the solar wind has a solar origin. However, the
fast and slow streams, shocks, and other nonlinear interactions can only be
considered as the drivers of the intermittent turbulence. It seems that
analysis shows that turbulence beyond the ecliptic plane evolves too slowly to
maintain the intermittency with the distance and latitude. Moreover, we confirm
that the multifractality and intermittency are at a lower level than in the
ecliptic, as well as the existence of symmetry with respect to the ecliptic
plane, suggesting that there are similar turbulent properties observed in the
two hemispheres.


title:
Global solutions to the isentropic compressible Navier-Stokes equations
  with a class of large initial data

abstract:
  In this paper, we consider the global well-posedness problem of the
isentropic compressible Navier-Stokes equations in the whole space $\R^N$ with
$N\ge2$. In order to better reflect the characteristics of the dispersion
equation, we make full use of the role of the frequency on the integrability
and regularity of the solution, and prove that the isentropic compressible
Navier-Stokes equations admit global solutions when the initial data are close
to a stable equilibrium in the sense of suitable hybrid Besov norm. As a
consequence, the initial velocity with arbitrary $\dot{B}^{\fr{N}{2}-1}_{2,1}$
norm of potential part $\Pe^\bot u_0$ and large highly oscillating are allowed
in our results. The proof relies heavily on the dispersive estimates for the
system of acoustics, and a careful study of the nonlinear terms.


title:
Time-of-flight expansion of trapped dipolar Fermi gases: From the
  collisionless to the hydrodynamic regime

abstract:
  A recent time-of-flight (TOF) expansion experiment with polarized fermionic
erbium atoms measured a Fermi surface deformation from a sphere to an ellipsoid
due to dipole-dipole interaction, thus confirming previous theoretical
predictions. Here we perform a systematic study of the ground-state properties
and TOF dynamics for trapped dipolar Fermi gases from the collisionless to the
hydrodynamic regime at zero temperature. To this end we solve analytically the
underlying Boltzmann-Vlasov equation within the relaxation-time approximation
in the vicinity of equilibrium by using a suitable rescaling of the equilibrium
distribution. The resulting ordinary differential equations for the respective
scaling parameters are then solved numerically for experimentally realistic
parameters and relaxation times that correspond to the collisionless,
collisional, and hydrodynamic regime. The equations for the collisional regime
are first solved in the approximation of a fixed relaxation time, and then this
approach is extended to include a self-consistent determination of the
relaxation time. The presented analytical and numerical results are relevant
for a detailed quantitative understanding of ongoing experiments and the design
of future experiments with ultracold fermionic dipolar atoms and molecules. In
particular, the obtained results are relevant for systems with strong
dipole-dipole interaction, which turn out to affect significantly the aspect
ratios during the TOF expansion.


title:
Equation of state for neutron star matter with NJL model and
  Dirac-Brueckner-Hartree-Fock approximation

abstract:
  As the interior density of a neutron star can become very high, it has been
expected and discussed that quark matter may exist inside it. To describe the
transition from hadron to quark phases (and vice versa), there are mainly two
methods; one is the first-order phase transition, and the other is the
crossover phenomenon. In the present study, using the flavor-SU (3) NJL model
with the vector coupling interaction, we have calculated the equation of state
for the quark phase at high density. Furthermore, for the hadron phase at low
density, we have used two kinds of the equations of state; one is a relatively
soft one by the QHD model, and the other is a stiff one calculated with
relativistic Brueckner-Hartree-Fock approximation. Using those equations of
state for the two phases, we have investigated the influence of various choices
of parameters concerning the crossover region on the mass and radius of a
neutron star.


title: Kondo cloud of single heavy quark in cold and dense matter

abstract:
  The Kondo effect is a universal phenomena observed in a variety of fermion
systems containing a heavy impurity particle whose interaction is governed by
the non-Abelian interaction. At extremely high density, I study the Kondo
effect by color exchange in quark matter containing a single heavy (charm or
bottom) quark as an impurity particle. To obtain the ground state with the
Kondo effect, I introduce the condensate mixing the light quark and the heavy
quark (Kondo cloud) in the mean-field approximation. I estimate the energy gain
by formation of the Kondo cloud, and present that the Kondo cloud exhibits the
resonant structure. I also evaluate the scattering cross section for the light
quark and the heavy quark, and discuss its effect to the finite size quark
matter.


title: Failure Detection for Facial Landmark Detectors

abstract:
  Most face applications depend heavily on the accuracy of the face and facial
landmarks detectors employed. Prediction of attributes such as gender, age, and
identity usually completely fail when the faces are badly aligned due to
inaccurate facial landmark detection. Despite the impressive recent advances in
face and facial landmark detection, little study is on the recovery from and
detection of failures or inaccurate predictions. In this work we study two top
recent facial landmark detectors and devise confidence models for their
outputs. We validate our failure detection approaches on standard benchmarks
(AFLW, HELEN) and correctly identify more than 40% of the failures in the
outputs of the landmark detectors. Moreover, with our failure detection we can
achieve a 12% error reduction on a gender estimation application at the cost of
a small increase in computation.


title:
Mass spectra in ${\cal N}=1$ SQCD with additional colorless fields.
  Strong coupling regimes

abstract:
  We consider the ${\cal N}=1$ $SU(N_c)$ SQCD-like (direct) theory (and its
Seiberg's dual with $SU(N_F-N_c)$ dual colors), and with $N_F$ flavors of light
quarks ${\overline Q}_j, Q^i$ with the mass term in the superpotential $m_Q{\rm
Tr}({\overline Q} Q),\,\, m_Q\ll\Lambda_Q$. Besides, there are $N_F^2$
additional colorless but flavored fields $\Phi^j_i$ with the large mass
parameter $\mu_{\Phi}\gg\Lambda_Q$. But now considered is the region
$N_c+1<N_F<3N_c/2$ where the UV free direct $SU(N_c)$ theory is strongly
coupled at scales $\mu<\Lambda_Q$.
  The mass spectra of this direct theory in various vacua and at different
values of $\mu_{\Phi}\gg\Lambda_Q$ are calculated within the dynamical scenario
introduced by the author in [10]. This scenario assumes that quarks in such
${\cal N}=1$ SQCD-like theories can be in two standard phases only. These are
either the HQ (heavy quark) phase where they are confined or the Higgs phase.
  It is shown that due to the strong power-like RG evolution, the seemingly
heavy and dynamically irrelevant at scales $\mu<\Lambda_Q$ fields $\Phi^j_i$
can become light and relevant at lower energies, and there appear then two
additional generation of light $\Phi$-particles with masses $\mu_{2,3}^{\rm
pole}(\Phi)\ll\Lambda_Q$.
  The calculated mass spectra of this strongly coupled at $\mu<\Lambda_Q\,
SU(N_c)$ theory are compared to those of its weakly coupled at $\mu<\Lambda_Q$
Seiberg's dual $SU(N_F-N_c)$ variant and appeared to be parametrically
different. It is worth to recall that the dynamical scenario from [10] used in
this article satisfies all those tests which were used as checks of the Seiberg
hypothesis about the equivalence of the direct and dual theories. This
parametrical difference shows, in particular, that all these tests, although
necessary, may well be insufficient.


title:
A new proof of the fundamental two-term transformation for the series
  ${}_3F_2(1)$ due to Thomae

abstract:
  The aim of this short note is to provide a very simple proof for obtaining
the fundamental two-term transformation for the series ${}_3F_2(1)$ due to
Thomae.


title:
Comment on a paper "Watson - like Formulae for terminating $_{3}F_2$
  series" by Chu and Zhou

abstract:
  In a recent paper, Chu and Zhou [Advances in Combinatorics, I.S. Kotsireas
and E.V. Zima(eds.), 139-159 (2013)] established in all 40 closed formulae for
terminating Watson-like hypergeometric $_{3}F_2$- series by investigating
through Gould and Hsu's fundamental pair of inverse series relations, the dual
relations of Dougall's formula for the very well - poised $_{5}F_4$ - series.
  The aim of this short note is just to point out that out of 40 results, 33
results have already been discovered in 1992 by Lavoie, et al.


title: On-demand entanglement generation using dynamic single-electron sources

abstract:
  We review our recent proposals for the on-demand generation of entangled
few-electron states using dynamic single-electron sources. The generation of
entanglement can be traced back to the single-electron entanglement produced by
quantum point contacts acting as electronic beam splitters. The coherent
partitioning of a single electron leads to entanglement between the two
outgoing arms of the quantum point contact. We describe our various approaches
for generating and certifying entanglement in dynamic electronic conductors and
we quantify the influence of detrimental effects such as finite electronic
temperatures and other dephasing mechanisms. The prospects for future
experiments are discussed and possible avenues for further developments are
identified.


title:
Discontinuous change from thermally- to geometrically- dominated
  effective interactions in colloidal solutions

abstract:
  We report numerical results for the effective potential arising between two
colloids immersed in a self-assembling cosolute which forms reversible
clusters. The potential is evaluated at cosolute state points with different
densities and temperatures but with the same connectivity properties. We find
that the range of the resulting effective potential is controlled only by the
cosolute thermal correlation length rather than by its connectivity length. We
discuss the significant differences with previous results focused on cosolute
forming irreversible clusters and we show that irreversible bond case
represents a singular limit which cannot be accessed in equilibrium by
continuously increasing the bond lifetime.


title: Dirichlet approximation and universal Dirichlet series

abstract:
  We characterize the uniform limits of Dirichlet polynomials on a right half
plane. In the Dirichlet setting, we find approximation results, with respect to
the Euclidean distance and {to} the chordal one as well, analogous to classical
results of Runge, Mergelyan and Vitushkin. We also strengthen the notion of
universal Dirichlet series.


title: Stack and Queue Layouts via Layered Separators

abstract:
  It is known that every proper minor-closed class of graphs has bounded
stack-number (a.k.a. book thickness and page number). While this includes
notable graph families such as planar graphs and graphs of bounded genus, many
other graph families are not closed under taking minors. For fixed $g$ and $k$,
we show that every $n$-vertex graph that can be embedded on a surface of genus
$g$ with at most $k$ crossings per edge has stack-number $\mathcal{O}(\log n)$;
this includes $k$-planar graphs. The previously best known bound for the
stack-number of these families was $\mathcal{O}(\sqrt{n})$, except in the case
of $1$-planar graphs. Analogous results are proved for map graphs that can be
embedded on a surface of fixed genus. None of these families is closed under
taking minors. The main ingredient in the proof of these results is a
construction proving that $n$-vertex graphs that admit constant layered
separators have $\mathcal{O}(\log n)$ stack-number.


title:
Tracking Amendments to Legislation and Other Political Texts with a
  Novel Minimum-Edit-Distance Algorithm: DocuToads

abstract:
  Political scientists often find themselves tracking amendments to political
texts. As different actors weigh in, texts change as they are drafted and
redrafted, reflecting political preferences and power. This study provides a
novel solution to the prob- lem of detecting amendments to political text based
upon minimum edit distances. We demonstrate the usefulness of two
language-insensitive, transparent, and efficient minimum-edit-distance
algorithms suited for the task. These algorithms are capable of providing an
account of the types (insertions, deletions, substitutions, and trans-
positions) and substantive amount of amendments made between version of texts.
To illustrate the usefulness and efficiency of the approach we replicate two
existing stud- ies from the field of legislative studies. Our results
demonstrate that minimum edit distance methods can produce superior measures of
text amendments to hand-coded efforts in a fraction of the time and resource
costs.


title:
The $\sigma$ exchange effect in the Lamb shift of muonic hydrogen by two
  photons and two pions exchange

abstract:
  Based on the simple phenomenological $\sigma \pi \pi$, $\sigma N N$ and $\pi
\pi \gamma$ interactions, we estimate the $\sigma$ exchange effect in the Lamb
shift of muonic hydrogen. We at first calculate the effective couplings of
$\sigma\mu\mu$ by two photons and two pions exchange, then calculate the
corresponding corrections to the energy shift of the 2S/2P states of muonic
hydrogen. We find the correction to the energy shift of 2S state is about
-14$\mu$eV by the current used parameters, which is about $44\%$ of the usual
two photons exchange contribution, and is larger than the current experimental
precision, and should be considered in the experimental analysis.


title:
Bogoliubov Fermi surfaces in superconductors with broken time-reversal
  symmetry

abstract:
  It is commonly believed that in the absence of disorder or an external
magnetic field, there are three possible types of superconducting excitation
gaps: the gap is nodeless, it has point nodes, or it has line nodes. Here, we
show that for an even-parity nodal superconducting state which spontaneously
breaks time-reversal symmetry, the low-energy excitation spectrum generally
does not belong to any of these categories, instead it has extended Bogoliubov
Fermi surfaces. These Fermi surfaces can be visualized as two-dimensional
surfaces generated by "inflating" point or line nodes into spheroids or tori,
respectively. These inflated nodes are topologically protected from being
gapped by a $\mathbb{Z}_2$ invariant, which we give in terms of a Pfaffian. We
also show that superconducting states possessing these Fermi surfaces can be
energetically stable. A crucial ingredient in our theory is that more than one
band is involved in the pairing, since all candidate materials for even-parity
superconductivity with broken time-reversal symmetry are multiband systems, we
expect these $\mathbb{Z}_2$-protected Fermi surfaces to be ubiquitous.


title:
On Low-High Orders of Directed Graphs: Incremental Algorithms and
  Applications

abstract:
  A flow graph $G=(V,E,s)$ is a directed graph with a distinguished start
vertex $s$. The dominator tree $D$ of $G$ is a tree rooted at $s$, such that a
vertex $v$ is an ancestor of a vertex $w$ if and only if all paths from $s$ to
$w$ include $v$. The dominator tree is a central tool in program optimization
and code generation and has many applications in other diverse areas including
constraint programming, circuit testing, biology, and in algorithms for graph
connectivity problems. A low-high order of $G$ is a preorder $\delta$ of $D$
that certifies the correctness of $D$ and has further applications in
connectivity and path-determination problems. In this paper, we first consider
how to maintain efficiently a low-high order of a flow graph incrementally
under edge insertions. We present algorithms that run in $O(mn)$ total time for
a sequence of $m$ edge insertions in an initially empty flow graph with $n$
vertices.These immediately provide the first incremental certifying algorithms
for maintaining the dominator tree in $O(mn)$ total time, and also imply
incremental algorithms for other problems. Hence, we provide a substantial
improvement over the $O(m^2)$ simple-minded algorithms, which recompute the
solution from scratch after each edge insertion. We also show how to apply
low-high orders to obtain a linear-time $2$-approximation algorithm for the
smallest $2$-vertex-connected spanning subgraph problem (2VCSS). Finally, we
present efficient implementations of our new algorithms for the incremental
low-high and 2VCSS problems and conduct an extensive experimental study on
real-world graphs taken from a variety of application areas. The experimental
results show that our algorithms perform very well in practice.


title:
Desorption Dynamics of Rb_2 Molecules off the Surface of Helium
  Nanodroplets

abstract:
  The desorption dynamics of rubidium dimers (Rb_2) off the surface of helium
nanodroplets induced by laser excitation is studied employing both nanosecond
and femtosecond ion imaging spectroscopy. Similarly to alkali metal atoms, we
find that the Rb_2 desorption process resembles the dissociation of a diatomic
molecule. However, both angular and energy distributions of detected Rb_2^+
ions appear to be most crucially determined by the Rb_2 intramolecular degrees
of freedom rather than by those of the Rb_2He_N complex. The pump-probe
dynamics of Rb_2^+ is found to be slower than that of Rb^+ pointing at a weaker
effective guest-host repulsion for excited molecules than for single atoms.


title:
Very-high-energy observations of the binaries V 404 Cyg and 4U 0115+634
  during giant X-ray outbursts

abstract:
  Transient X-ray binaries produce major outbursts in which the X-ray flux can
increase over the quiescent level by factors as large as $10^7$. The low-mass
X-ray binary V 404 Cyg and the high-mass system 4U 0115+634 underwent such
major outbursts in June and October 2015, respectively. We present here
observations at energies above hundreds of GeV with the VERITAS observatory
taken during some of the brightest X-ray activity ever observed from these
systems. No gamma-ray emission has been detected by VERITAS in 2.5 hours of
observations of the microquasar V 404 Cyg from 2015, June 20-21. The upper flux
limits derived from these observations on the gamma-ray flux above 200 GeV of F
$< 4.4\times 10^{-12}$ cm$^{-2}$ s$^{-1}$ correspond to a tiny fraction (about
$10^{-6}$) of the Eddington luminosity of the system, in stark contrast to that
seen in the X-ray band. No gamma rays have been detected during observations of
4U 0115+634 in the period of major X-ray activity in October 2015. The flux
upper limit derived from our observations is F $< 2.1\times 10^{-12}$ cm$^{-2}$
s$^{-1}$ for gamma rays above 300 GeV, setting an upper limit on the ratio of
gamma-ray to X-ray luminosity of less than 4%.


title: Connected components of moduli spaces of generalised Kummer varieties

abstract:
  Moduli spaces of polarised (with fixed polarisation type) irreducible
holomorphic symplectic manifolds deformation equivalent to Hilbert schemes of
points on $K3$ surfaces are not connected in general and A. Apostolov counted
the number of their components. We extend Apostolov's results to the case of
manifolds deformation equivalent to generalised Kummer varieties.


title: Real bundle gerbes, orientifolds and twisted KR-homology

abstract:
  We consider Real bundle gerbes on manifolds equipped with an involution and
prove that they are classified by their Real Dixmier-Douady class in
Grothendieck's equivariant sheaf cohomology. We show that the Grothendieck
group of Real bundle gerbe modules is isomorphic to twisted KR-theory for a
torsion Real Dixmier-Douady class. Using these modules as building blocks, we
introduce geometric cycles for twisted KR-homology and prove that they generate
a real-oriented generalised homology theory dual to twisted KR-theory for Real
closed manifolds, and more generally for Real finite CW-complexes, for any Real
Dixmier-Douady class. This is achieved by defining an explicit natural
transformation to analytic twisted KR-homology and proving that it is an
isomorphism. Our model both refines and extends previous results by Wang and
Baum-Carey-Wang to the Real setting. Our constructions further provide a new
framework for the classification of orientifolds in string theory, providing
precise conditions for orientifold lifts of H-fluxes and for orientifold
projections of open string states.


title: On the isometry group of $RCD^*(K,N)$-spaces

abstract:
  We prove that the group of isometries of a metric measure space that
satisfies the Riemannian curvature condition, $RCD^*(K,N),$ is in fact a Lie
group. We obtain an optimal upper bound on its dimension and classify the
spaces where this maximal dimension is achieved.


title:
On the gauge-invariant operator $A^2_{\min}$ in Euclidean Yang-Mills
  theories

abstract:
  We review our recent work on the gauge-invariant non-local dimension-two
operator $A^2_{\rm min}$, whose minimization is defined along the gauge orbit.
Albeit non-local, the operator $A^2_{\rm min}$ can be cast in local form
through the introduction of an auxiliary Stueckelberg field. The whole
procedure results into a local action which turns out to be renormalizable to
all orders.


title: Warehousing Complex Archaeological Objects

abstract:
  Data organization is a difficult and essential component in cultural heritage
applications. Over the years, a great amount of archaeological ceramic data
have been created and processed by various methods and devices. Such ceramic
data are stored in databases that concur to increase the amount of available
information rapidly. However , such databases typically focus on one type of
ceramic descriptors, e.g., qualitative textual descriptions, petrographic or
chemical analysis results, and do not interoperate. Thus, research involving
archaeological ceramics cannot easily take advantage of combining all these
types of information. In this application paper, we introduce an evolution of
the Ceramom database that includes text descriptors of archaeological features,
chemical analysis results, and various images, including petrographic and
fabric images. To illustrate what new analyses are permitted by such a
database, we source it to a data warehouse and present a sample on-line
analysis processing (OLAP) scenario to gain deep understanding of ceramic
context.


title: Natural Supersymmetry from Extra Dimensions

abstract:
  We show that natural supersymmetry can be embedded in a five-dimensional
theory with supersymmetry breaking \`a la Scherk-Schwarz (SS). There is no
'gluino-sucks' problem for stops localized in the four-dimensional brane and
gluinos propagating in the full five-dimensional bulk, and sub-TeV stops are
easily accommodated. The $\mu / B_\mu$ problem is absent as well; the SS
breaking generates a Higgsino Dirac mass and no bilinear Higgs mass parameter
in the superpotential is required. Moreover, for non-maximal SS twists leading
to $\tan \beta \simeq 1$, the Higgs spectrum is naturally split, in agreement
with LHC data. The 125-GeV Higgs mass and radiative electroweak symmetry
breaking can be accommodated by minimally extending the Higgs sector with $Y=0$
$SU(2)_L$ triplets.


title:
Evidence of natural hybridization and introgression between Medicago
  ciliaris and Medicago intertexta

abstract:
  The present study, investigated some reproductive and fertility parameters in
some wild populations, originating from the North Tunisia (4 populations of
Medicago ciliaris and 3 populations of Medicago intertexta). Previous finding
revealed that these species are genetically distinct and easily recognized by
the number of flowers per inflorescence and pod dimensions. However,
biometrical traits and isozyme patterns intermediacy between these two species
had detected the existence of a potential spontaneous interspecific hybrid
originating from Sedjnane locality in Tunisia. Indeed, the present work has
shown significant decrease of pollen fertility and seed production for this
population when compared to the others(pollen viability 75%, pollen
germinability 8% and pod production=9%). These results suggested a possible
natural interspecific hybrid and confirming introgressive hybridization
possibility between M. intertexta and M. ciliaris.


title:
Multivariate Cryptography with Mappings of Discrete Logarithms and
  Polynomials

abstract:
  In this paper, algorithms for multivariate public key cryptography and
digital signature are described. Plain messages and encrypted messages are
arrays, consisting of elements from a fixed finite ring or field. The
encryption and decryption algorithms are based on multivariate mappings. The
security of the private key depends on the difficulty of solving a system of
parametric simultaneous multivariate equations involving polynomial or
exponential mappings. The method is a general purpose utility for most data
encryption, digital certificate or digital signature applications.