title:
Nuclear pseudo-differential operators in Besov spaces on compact Lie
  groups

abstract:
  In this work we establish the metric approximation property for Besov spaces
defined on arbitrary compact Lie groups. As a consequence of this fact, we
investigate trace formulae for nuclear Fourier multipliers on Besov spaces.
Finally, we study the r-nuclearity, the Grothendieck-Lidskii formula and the
(nuclear) trace of pseudo-differential operators in generalized H\"ormander
classes acting on periodic Besov spaces. We will restrict our attention to
pseudo-differential operators with symbols of limited regularity.


title: Radio light curve of the galaxy possibly associated with FRB150418

abstract:
  We present observations made with the Australia Telescope Compact Array
(ATCA), the Jansky Very Large Array (JVLA) and the Giant Metre-Wave Telescope
of the radio source within the galaxy WISE~J071634.59-190039.2, claimed to be
host of FRB~150418 by Keane et al. (2016). We have established a common flux
density scale between the ATCA and JVLA observations, the main result of which
is to increase the flux densities obtained by Keane et al. At a frequency of
5.5 GHz, the source has a mean flux density of 140uJy and is variable on short
timescales with a modulation index of 0.36. Statistical analysis of the flux
densities shows that the variations seen are consistent with refractive
interstellar scintillation of the weak active galactic nucleus at the centre of
the galaxy. It may therefore be the case that the FRB and the galaxy are not
associated. However, taking into account the rarity of highly variable sources
in the radio sky, and our lack of knowledge of the progenitors of FRBs as a
class, the association between WISE~J071634.59-190039.2 and FRB~150418 remains
a possibility.


title: BehavioCog: An Observation Resistant Authentication Scheme

abstract:
  We propose that by integrating behavioural biometric gestures---such as
drawing figures on a touch screen---with challenge-response based cognitive
authentication schemes, we can benefit from the properties of both. On the one
hand, we can improve the usability of existing cognitive schemes by
significantly reducing the number of challenge-response rounds by (partially)
relying on the hardness of mimicking carefully designed behavioural biometric
gestures. On the other hand, the observation resistant property of cognitive
schemes provides an extra layer of protection for behavioural biometrics; an
attacker is unsure if a failed impersonation is due to a biometric failure or a
wrong response to the challenge. We design and develop an instantiation of such
a "hybrid" scheme, and call it BehavioCog. To provide security close to a
4-digit PIN---one in 10,000 chance to impersonate---we only need two
challenge-response rounds, which can be completed in less than 38 seconds on
average (as estimated in our user study), with the advantage that unlike PINs
or passwords, the scheme is secure under observation.


title: Machine Learning Model Interpretability for Precision Medicine

abstract:
  Interpretability of machine learning models is critical for data-driven
precision medicine efforts. However, highly predictive models are generally
complex and are difficult to interpret. Here using Model-Agnostic Explanations
algorithm, we show that complex models such as random forest can be made
interpretable. Using MIMIC-II dataset, we successfully predicted ICU mortality
with 80% balanced accuracy and were also were able to interpret the relative
effect of the features on prediction at individual level.


title: The Hydration Structure of Carbon Monoxide by Ab Initio Methods

abstract:
  The solvation of carbon monoxide (CO) in liquid water is important for
understanding its toxicological effects and biochemical roles. In this paper,
we use ab initio molecular dynamics (AIMD) and CCSD(T)-F12 calculations to
assess the accuracy of the Straub and Karplus molecular mechanical (MM) model
for CO(aq). The CCSD(T)-F12 CO--H2O potential energy surfaces show that the
most stable structure corresponds to water donating a hydrogen bond to the C
center. The MM-calculated surface it incorrectly predicts that the O atom is a
stronger hydrogen bond acceptor than the C atom. The AIMD simulations indicate
that CO is solvated like a hydrophobic solute, with very limited hydrogen
bonding with water. The MM model tends to overestimate the degree of hydrogen
bonding and overestimates the atomic radius of the C atom. The calculated Gibbs
energy of hydration is in good agreement with experiment (9.3 kJ/mol calc. vs
10.7 kJ/mol exptl.). The calculated diffusivity of CO(aq) in TIP3P-model water
was 5.19 x 10-5 cm2/s calc., more than double the experimental value of 2.32 x
10-5 cm2/s


title:
The Zeeman Effect in the 44 GHz Class I Methanol Maser Line toward
  DR21(OH)

abstract:
  We report the detection of the Zeeman effect in the 44 GHz Class I methanol
maser line toward the star forming region DR21(OH). In a 219 Jy/beam maser
centered at an LSR velocity of 0.83 km s$^{-1}$, we find a 20-$\sigma$
detection of $zB_{\text{los}} = 53.5 \pm 2.7$ Hz. If 44 GHz methanol masers are
excited at $n \sim 10^{7-8}$ cm$^{-3}$, then the $B~vs.~n^{1/2}$ relation would
imply from comparison with Zeeman effect detections in the CN($1-0$) line
toward DR21(OH) that magnetic fields traced by 44 GHz methanol masers in
DR21(OH) should be $\sim$10 mG. Together with our detected $zB_{\text{los}} =
53.5$ Hz, this would imply that the value of the 44 GHz methanol Zeeman
splitting factor $z$ is $\sim$5 Hz mG$^{-1}$. Such small values of $z$ would
not be a surprise, as the methanol molecule is non paramagnetic, like H$_2$O.
Empirical attempts to determine $z$, as demonstrated, are important because
currently there are no laboratory measurements or theoretically calculated
values of $z$ for the 44 GHz methanol transition. Data from observations of a
larger number of sources are needed to make such empirical determinations
robust.


title: Latent geometry of bipartite networks

abstract:
  Despite the abundance of bipartite networked systems, their organizing
principles are less studied, compared to unipartite networks. Bipartite
networks are often analyzed after projecting them onto one of the two sets of
nodes. As a result of the projection, nodes of the same set are linked together
if they have at least one neighbor in common in the bipartite network. Even
though these projections allow one to study bipartite networks using tools
developed for unipartite networks, one-mode projections lead to significant
loss of information and artificial inflation of the projected network with
fully connected subgraphs. Here we pursue a different approach for analyzing
bipartite systems that is based on the observation that such systems have a
latent metric structure: network nodes are points in a latent metric space,
while connections are more likely to form between nodes separated by shorter
distances. This approach has been developed for unipartite networks, and
relatively little is known about its applicability to bipartite systems. Here,
we fully analyze a simple latent-geometric model of bipartite networks, and
show that this model explains the peculiar structural properties of many real
bipartite systems, including the distributions of common neighbors and
bipartite clustering. We also analyze the geometric information loss in
one-mode projections in this model, and propose an efficient method to infer
the latent pairwise distances between nodes. Uncovering the latent geometry
underlying real bipartite networks can find applications in diverse domains,
ranging from constructing efficient recommender systems to understanding cell
metabolism.


title: Data-driven time parallelism via forecasting

abstract:
  This work proposes a data-driven method for enabling the efficient, stable
time-parallel numerical solution of systems of ordinary differential equations
(ODEs). The method assumes that low-dimensional bases that accurately capture
the time evolution of the state are available. The method adopts the parareal
framework for time parallelism, which is defined by an initialization method, a
coarse propagator, and a fine propagator. Rather than employing usual
approaches for initialization and coarse propagation, we propose novel
data-driven techniques that leverage the available time-evolution bases. The
coarse propagator is defined by a forecast (proposed in Ref. [12]) applied
locally within each coarse time interval, which comprises the following steps:
(1) apply the fine propagator for a small number of time steps, (2) approximate
the state over the entire coarse time interval using gappy POD with the local
time-evolution bases, and (3) select the approximation at the end of the time
interval as the propagated state. We also propose both local-forecast and
global-forecast initialization. The method is particularly well suited for
POD-based reduced-order models (ROMs). In this case, spatial parallelism
quickly saturates, as the ROM dynamical system is low dimensional; thus, time
parallelism is needed to enable lower wall times. Further, the time-evolution
bases can be extracted from the (readily available) right singular vectors
arising during POD computation. In addition to performing analyses related to
the method's accuracy, speedup, stability, and convergence, we also numerically
demonstrate the method's performance. Here, numerical experiments on ROMs for a
nonlinear convection-reaction problem demonstrate the method's ability to
realize near-ideal speedups; global-forecast initialization with a
local-forecast coarse propagator leads to the best performance.


title: Dynamo-driven plasmoid formation from a current-sheet instability

abstract:
  Axisymmetric current-carrying plasmoids are formed in the presence of
nonaxisymmetric fluctuations during nonlinear three-dimensional resistive MHD
simulations in a global toroidal geometry. We utilize the helicity injection
technique to form an initial poloidal flux in the presence of a toroidal guide
field. As helicity is injected, two types of current sheets are formed from 1)
the oppositely directed field lines in the injector region (primary
reconnecting current sheet), and 2) the poloidal flux compression near the
plasma edge (edge current sheet). We first find that nonaxisymmetic
fluctuations arising from the current-sheet instability isolated near the
plasma edge have tearing parity but can nevertheless grow fast (on the poloidal
Alfven time scale). These modes saturate by breaking up the current sheet.
Second, for the first time a dynamo poloidal flux amplification is observed at
the reconnetion site (in the region of the oppositely directed magnetic field).
This fluctuation-induced flux amplification increases the local Lundquist
number, which then triggers a plasmoid instability and breaks the primary
current sheet at the reconnection site. The plasmoids formation driven by
large-scale flux amplification, i.e. a large-scale dynamo, observed here has
strong implications for astrophysical reconnection as well as fast reconnection
events in laboratory plasmas.


title: The Geometry of Synchronization Problems and Learning Group Actions

abstract:
  We develop a geometric framework that characterizes the synchronization
problem --- the problem of consistently registering or aligning a collection of
objects. The theory we formulate characterizes the cohomological nature of
synchronization based on the classical theory of fibre bundles. We first
establish the correspondence between synchronization problems in a topological
group $G$ over a connected graph $\Gamma$ and the moduli space of flat
principal $G$-bundles over $\Gamma$, and develop a discrete analogy of the
renowned theorem of classifying flat principal bundles with fix base and
structural group using the representation variety. In particular, we show that
prescribing an edge potential on a graph is equivalent to specifying an
equivalence class of flat principal bundles, of which the triviality of
holonomy dictates the synchronizability of the edge potential. We then develop
a twisted cohomology theory for associated vector bundles of the flat principal
bundle arising from an edge potential, which is a discrete version of the
twisted cohomology in differential geometry. This theory realizes the
obstruction to synchronizability as a cohomology group of the twisted de Rham
cochain complex. We then build a discrete twisted Hodge theory --- a fibre
bundle analog of the discrete Hodge theory on graphs --- which geometrically
realizes the graph connection Laplacian as a Hodge Laplacian of degree zero.
Motivated by our geometric framework, we study the problem of learning group
actions --- partitioning a collection of objects based on the local
synchronizability of pairwise correspondence relations. A dual interpretation
is to learn finitely generated subgroups of an ambient transformation group
from noisy observed group elements. A synchronization-based algorithm is also
provided, and we demonstrate its efficacy using simulations and real data.


title: A local and operational framework for the foundations of physics

abstract:
  We discuss a novel framework for physical theories that is based on the
principles of locality and operationalism. It generalizes and unifies previous
frameworks, including the standard formulation of quantum theory, the convex
operational framework and Segal's approach to quantum field theory. It is
capable of encoding both classical and quantum (field) theories, implements
spacetime locality in a manifest way and contains the complete modern notion of
measurement in the quantum case. Its mathematical content can be condensed into
a set of axioms that are similar to those of Atiyah and Segal. This is
supplemented by two basic rules for extracting probabilities or expectation
values for measurement processes. The framework, called the positive formalism,
is derived in three completely different ways. One derivation is from first
principles, one starts with classical field theory and one with quantum field
theory. The latter derivation arose previously in the programme of the general
boundary formulation of quantum theory. As in the convex operational framework,
the difference between classical and quantum theories essentially arises from
certain partially ordered vector spaces being either lattices or anti-lattices.
If we add the ad hoc ingredient of imposing anti-lattice structures, the
derivation from first principles may be seen as a reconstruction of quantum
theory. Among other things, the positive formalism suggests a statistical
approach to classical field theories with dynamical metric, provides a common
ground for quantum information theory and quantum field theory, introduces a
notion of local measurement into quantum field theory, and suggests a new
perspective on quantum gravity by removing the incompatibility with general
relativistic principles.


title: Higher-order nonclassical effects in fluctuating-loss channels

abstract:
  We study the evolution of higher-order nonclassicality and entanglement
criteria in atmospheric fluctuating-loss channels. By formulating input-output
relations for the matrix of moments, we investigate the influence of such
channels on the corresponding quantumness criteria. This generalization of our
previous work on Gaussian entanglement [M. Bohmann et al., Phys. Rev. A 94,
010302(R) (2016)] not only exploits second-order-based scenarios, but it also
provides a detailed investigation of nonclassicality and entanglement in
non-Gaussian and multimode radiation fields undergoing a fluctuating
attenuation. That is, various examples of criteria and states are studied in
detail, unexpected effects, e.g., the dependency of the squeezing transfer on
the coherent displacement, are discovered, and it is demonstrated that
non-Gaussian entanglement can be more robust against atmospheric losses than
Gaussian one. Additionally, we propose a detection scheme for measuring the
considered moments after propagation through the atmosphere. Therefore, our
results may help to develop, improve, and optimize non-Gaussian sources of
quantum light for applications in free-space quantum communication.


title: Broadcast Coded Modulation: Multilevel and Bit-interleaved Construction

abstract:
  The capacity of the AWGN broadcast channel is achieved by superposition
coding, but superposition of individual coded modulations expands the
modulation alphabet and distorts its configuration. Coded modulation over a
broadcast channel subject to a specific channel-input modulation constraint
remains an important open problem. Some progress has been made in the related
area of unequal-error protection modulations which can be considered
single-user broadcast transmission, but it does not approach all points on the
boundary of the capacity region. This paper studies broadcast coded modulation
using multilevel coding (MLC) subject to a specific channel input
constellation. The conditions under which multilevel codes can achieve the
constellation-constrained capacity of the AWGN broadcast channel are derived.
For any given constellation, we propose a pragmatic multilevel design technique
with near constellation-constrained-capacity performance where the coupling of
the superposition inner and outer codes are localized to each bit-level. It is
shown that this can be further relaxed to a code coupling on only one bit
level, with little or no penalty under natural labeling. The rate allocation
problem between the bit levels of the two users is studied and a pragmatic
method is proposed, again with near-capacity performance. In further pursuit of
lower complexity, a hybrid MLC-BICM is proposed, whose performance is shown to
be very close to the boundary of the constellation-constrained capacity region.
Simulation results show that good point-to-point LDPC codes produce excellent
performance in the proposed coded modulation framework.


title:
ATLASGAL-selected massive clumps in the inner Galaxy III. Dust Continuum
  Characterization of an Evolutionary Sample

abstract:
  The ATLASGAL survey provides an ideal basis for detailed studies of large
numbers of massive star forming clumps covering the whole range of evolutionary
stages. The ATLASGAL Top100 is a sample of clumps selected from their infrared
and radio properties to be representative for the whole range of evolutionary
stages. The ATLASGAL Top100 sources are the focus of a number of detailed
follow-up studies that will be presented in a series of papers. In the present
work we use the dust continuum emission to constrain the physical properties of
this sample and identify trends as a function of source evolution.
  We determine flux densities from mid-infrared to submm wavelength (8-870
micron) images and use these values to fit their spectral energy distributions
(SEDs) and determine their dust temperature and flux. Combining these with
recent distances from the literature including maser parallax measurements we
determine clump masses, luminosities and column densities. We find trends for
increasing temperature, luminosity and column density with the proposed
evolution sequence, confirming that this sample is representative of different
evolutionary stages of massive star formation. We show that most of the sample
has the ability to form massive stars (including the most massive O-type stars)
and that the majority is gravitationally unstable and hence likely to be
collapsing.
  The highest column density ATLASGAL sources presented cover the whole range
of evolutionary stages from the youngest to the most evolved high-mass star
forming clumps. Their study provides a unique starting point for more in-depth
research on massive star formation in four distinct evolutionary stages whose
well defined physical parameters afford more detailed studies. As most of the
sample is closer than 5 kpc, these sources are also ideal for follow-up
observations with high spatial resolution.


title:
Scrape-Off Layer Turbulence in Tokamaks Simulated with a Continuum
  Gyrokinetic Code

abstract:
  We are developing a new continuum gyrokinetic code, Gkeyll, for use in edge
plasma simulations, and here present initial simulations of turbulence on open
field lines with model sheath boundary conditions. The code implements an
energy conserving discontinuous Galerkin scheme, applicable to a general class
of Hamiltonian equations. Several applications to test problems have been done,
including a calculation of the parallel heat-flux on divertor plates resulting
from an ELM crash in JET, for a 1x/1v SOL scenario explored previously, where
the ELM is modeled as a time-dependent intense upstream source. Here we present
initial simulations of turbulence on open field lines in the LAPD linear plasma
device. We have also done simulations in a helical open-field-line geometry.
While various simplifications have been made at present, this still includes
some of the key physics of SOL turbulence, such as bad-curvature drive for
instabilities and rapid parallel losses with sheath boundary conditions. This
is useful for demonstrating the overall feasibility of this approach and for
initial physics studies of SOL turbulence. We developed a novel version of DG
that uses Maxwellian-weighted basis functions while still preserving exact
particle and energy conservation. The Maxwellian-weighted DG method achieves
the same error with 4 times less computational cost in 1v, or 16 times lower
cost in the 2 velocity dimensions of gyrokinetics (assuming memory bandwidth is
the limiting factor).


title: Measure-valued P\'olya processes

abstract:
  A P\'olya urn process is a Markov chain that models the evolution of an urn
containing some coloured balls, the set of possible colours being
$\{1,\ldots,d\}$ for $d\in \mathbb{N}$. At each time step, a random ball is
chosen uniformly in the urn. It is replaced in the urn and, if its colour is
$c$, $R_{c,j}$ balls of colour $j$ are also added (for all $1\leq j\leq d$). We
introduce a model of measure-valued processes that generalises this
construction. This generalisation includes the case when the space of colours
is a (possibly infinite) Polish space $\mathcal P$.
  We see the urn composition at any time step $n$ as a measure ${\mathcal M}_n$
-- possibly non atomic -- on $\mathcal P$. In this generalisation, we choose a
random colour $c$ according to the probability distribution proportional to
${\mathcal M}_n$, and add a measure ${\mathcal R}_c$ in the urn, where the
quantity ${\mathcal R}_c(B)$ of a Borel set $B$ models the added weight of
"balls" with colour in $B$.
  We study the asymptotic behaviour of these measure-valued P\'olya urn
processes, and give some conditions on the replacements measures $({\mathcal
R}_c, c\in \mathcal P)$ for the sequence of measures $({\mathcal M}_n, n\geq
0)$ to converge in distribution, possibly after rescaling. For certain models,
related to branching random walks, $({\mathcal M}_n, n\geq 0)$ is shown to
converge almost surely under some moment hypothesis; a particular case of this
last result gives the almost sure convergence of the (renormalised) profile of
the random recursive tree to a standard Gaussian.


title:
Scheduling Distributed Clusters of Parallel Machines: Primal-Dual and
  LP-based Approximation Algorithms [Full Version]

abstract:
  The Map-Reduce computing framework rose to prominence with datasets of such
size that dozens of machines on a single cluster were needed for individual
jobs. As datasets approach the exabyte scale, a single job may need distributed
processing not only on multiple machines, but on multiple clusters. We consider
a scheduling problem to minimize weighted average completion time of N jobs on
M distributed clusters of parallel machines. In keeping with the scale of the
problems motivating this work, we assume that (1) each job is divided into M
"subjobs" and (2) distinct subjobs of a given job may be processed
concurrently.
  When each cluster is a single machine, this is the NP-Hard concurrent open
shop problem. A clear limitation of such a model is that a serial processing
assumption sidesteps the issue of how different tasks of a given subjob might
be processed in parallel. Our algorithms explicitly model clusters as pools of
resources and effectively overcome this issue.
  Under a variety of parameter settings, we develop two constant factor
approximation algorithms for this problem. The first algorithm uses an LP
relaxation tailored to this problem from prior work. This LP-based algorithm
provides strong performance guarantees. Our second algorithm exploits a
surprisingly simple mapping to the special case of one machine per cluster.
This mapping-based algorithm is combinatorial and extremely fast. These are the
first constant factor approximations for this problem.


title: Mathematical Physics Properties of Waves on Finite Background

abstract:
  Several mathematical and physical aspects of waves on finite background are
reported in this article. The evolution of the complex wave packet envelope of
these type of waves is governed by the focussing-type of the nonlinear
Schr\"{o}dinger (NLS) equation. The NLS equation admits a number of exact
solutions; in this article, we only discuss waves on finite background type of
solutions that have been proposed as theoretical models for freak wave events.
Three types of waves on finite background considered in this article are known
as the Soliton on Finite Background (SFB), the Ma solution and the rational
solution. In particular, two families of the SFB solutions deserve our special
attention. These are SFB$_{1}$ and SFB$_{2}$, where the latter one belongs to
higher order waves on finite background type of solution. These families of
solutions describe the Benjamin-Feir modulational instability phenomenon, which
has been verified theoretically, numerically and experimentally as the
phenomenon that a uniform continuous wave train is unstable under a very long
modulational perturbations of its envelope. A distinct difference between the
two families of solutions can be observed in the spectral domain, where
SFB$_{1}$ has one pair of initial sidebands and SFB$_{2}$ has two pairs of
initial sidebands within the interval of instability. The relationship between
SFB$_{1}$ and SFB$_{2}$ are explained and some important physical
characteristics of the two solutions are discussed. These include the amplitude
amplification factor, the spatial evolution of complex-valued envelopes, their
corresponding physical wave fields and the evolution of the corresponding wave
signals. Interestingly, wavefront dislocation and phase singularity are
observed in both families of the solution with different patterns, depending on
the value of the modulation wavelength and on the choice of parameters in
SFB$_{2}$.


title: Intensity mapping of H-alpha, H-beta, [OII] and [OIII] lines at z<5

abstract:
  Intensity mapping is now becoming a useful tool to study the large-scale
structure of the universe through spatial variations in the integrated emission
from galaxies and the intergalactic medium. We study intensity mapping of the
H-alpha 6563AA, [OIII]5007AA, [OII]3727AA and H-beta 4861AA lines at 0.8<z<5.2.
The mean intensities of these four emission lines are estimated using the
observed luminosity functions (LFs), cosmological simulations, and the star
formation rate density (SFRD) derived from observations at z<5. We calculate
the intensity power spectra and consider the foreground contamination of other
lines at lower redshifts. We use the proposed NASA small explorer SPHEREx (the
Spectro-Photometer for the History of the Universe, Epoch of Reionization, and
Ices Explorer) as a case study for the detectability of the intensity power
spectra of the four emission lines. We also investigate the cross correlation
with the 21-cm line probed by CHIME (the Canadian Hydrogen Intensity Mapping
Experiment), Tianlai experiment and SKA (the Square Kilometer Array) at
0.8<z<2.4. We find both the auto and cross power spectra can be well measured
for the H-alpha, [OIII] and [OII] lines at z<3, while it is more challenging
for the H-beta line. Finally, we estimate the constraint on the SFRD from
intensity mapping, and find we can reach accuracy higher than 7% at z<4, which
is better than usual measurements using the LFs of galaxies.


title:
Evidence for magnetar formation in broad-lined type Ic supernovae 1998bw
  and 2002ap

abstract:
  Broad-lined type Ic supernovae (SNe Ic-BL) are peculiar stellar explosions
that distinguish themselves from ordinary SNe. Some SNe Ic-BL are associated
with long-duration (\gtrsim 2 s) gamma-ray bursts (GRBs). Black holes and
magnetars are two types of compact objects that are hypothesized to be central
engines of GRBs. In spite of decades of investigations, no direct evidence for
the formation of black holes or magnetars has been found for GRBs so far. Here
we report the finding that the early peak (t \lesssim 50 days) and late-time (t
\gtrsim 300 days) slow decay displayed in the light curves of both SNe 1998bw
(associated with GRB 980425) and 2002ap (not GRB-associated) can be attributed
to magnetar spin-down with initial rotation period P0 \sim 20 ms, while the
intermediate-time (50 \lesssim t \lesssim 300 days) linear decline is caused by
radioactive decay of 56Ni. The connection between the early peak and late-time
slow decline in the light curves is unexpected in alternative models. We thus
suggest that GRB 980425 and SN 2002ap were powered by magnetars.


title:
Isolated singularities of positive solutions for Choquard equations in
  sublinear case

abstract:
  Our purpose of this paper is to study the isolated singularities of positive
solutions to Choquard equation in the sublinear case $q \in (0,1)$
  $$\displaystyle \ \ -\Delta u+ u =I_\alpha[u^p] u^q\;\;
  {\rm in}\; \mathbb{R}^N\setminus\{0\},
  % [2mm] \phantom{ }
  \;\; \displaystyle \lim_{|x|\to+\infty}u(x)=0, $$ where $p >0, N \geq 3,
\alpha \in (0,N)$ and $I_{\alpha}[u^p](x) = \int_{\mathbb{R}^N}
\frac{u^p(y)}{|x-y|^{N-\alpha}}dy$ is the Riesz potential, which appears as a
nonlocal term in the equation. We investigate the nonexistence and existence of
isolated singular solutions of Choquard equation under different range of the
pair of exponent $(p,q)$. Furthermore, we obtain qualitative properties for the
minimal singular solutions of the equation.


title:
On Generalized Heawood Inequalities for Manifolds: a van
  Kampen--Flores-type Nonembeddability Result

abstract:
  The fact that the complete graph $K_5$ does not embed in the plane has been
generalized in two independent directions. On the one hand, the solution of the
classical Heawood problem for graphs on surfaces established that the complete
graph $K_n$ embeds in a closed surface $M$ (other than the Klein bottle) if and
only if $(n-3)(n-4)\leq 6b_1(M)$, where $b_1(M)$ is the first $\mathbb
Z_2$-Betti number of $M$. On the other hand, van Kampen and Flores proved that
the $k$-skeleton of the $n$-dimensional simplex (the higher-dimensional
analogue of $K_{n+1}$) embeds in $\mathbb R^{2k}$ if and only if~$n \le 2k+1$.
  Two decades ago, K\"uhnel conjectured that the $k$-skeleton of the
$n$-simplex embeds in a compact, $(k-1)$-connected $2k$-manifold with $k$th
$\mathbb Z_2$-Betti number $b_k$ only if the following generalized Heawood
inequality holds: $\binom{n-k-1}{k+1} \le \binom{2k+1}{k+1}b_k$. This is a
common generalization of the case of graphs on surfaces as well as the van
Kampen--Flores theorem (the special cases $k=1$ and $b_k=0$, respectively), and
also closely related to the theory of face numbers of triangulated manifolds.
  In the spirit of K\"uhnel's conjecture, we prove that if the $k$-skeleton of
the $n$-simplex embeds in a $2k$-manifold with $k$th $\mathbb Z_2$-Betti number
$b_k$, then $n \le 2b_k\binom{2k+2}{k} + 2k + 4$. This bound is weaker than the
generalized Heawood inequality, but does not require the assumption that $M$ is
$(k-1)$-connected. Our results generalize to maps without $q$-covered points,
in the spirit of Tverberg's theorem, for $q$ a prime power. Our proof uses a
result of Volovikov about maps that satisfy a certain homological triviality
condition.


title:
Identifying Unknown Unknowns in the Open World: Representations and
  Policies for Guided Exploration

abstract:
  Predictive models deployed in the real world may assign incorrect labels to
instances with high confidence. Such errors or unknown unknowns are rooted in
model incompleteness, and typically arise because of the mismatch between
training data and the cases encountered at test time. As the models are blind
to such errors, input from an oracle is needed to identify these failures. In
this paper, we formulate and address the problem of informed discovery of
unknown unknowns of any given predictive model where unknown unknowns occur due
to systematic biases in the training data. We propose a model-agnostic
methodology which uses feedback from an oracle to both identify unknown
unknowns and to intelligently guide the discovery. We employ a two-phase
approach which first organizes the data into multiple partitions based on the
feature similarity of instances and the confidence scores assigned by the
predictive model, and then utilizes an explore-exploit strategy for discovering
unknown unknowns across these partitions. We demonstrate the efficacy of our
framework by varying the underlying causes of unknown unknowns across various
applications. To the best of our knowledge, this paper presents the first
algorithmic approach to the problem of discovering unknown unknowns of
predictive models.


title: On the Waring Rank of Binary Forms

abstract:
  The $K$-rank of a binary form $f$ in $K[x,y],~K\subseteq \mathbb{C},$ is the
smallest number of $d$-th powers of linear forms over $K$ of which $f$ is a
$K$-linear combination. We provide lower bounds for the $\mathbb{C}$-rank
(Waring rank) and for the $\mathbb{R}$-rank (real Waring rank) of binary forms
depending on their factorization. We completely classify binary forms of Waring
rank 3.


title:
Tertiary particle production and target optimization of the H2 beam line
  in the SPS North Area

abstract:
  In this note, the tertiary particle yield from secondary targets of different
materials placed at the 'filter' position of the H2 beam line of SPS North Area
are presented. The production is studied for secondary beams of different
momenta in the range of 50-250 GeV/c. More specifically, we studied six
different targets: two copper cylinders with a radius of 40 mm and lengths of
100 and 300 mm, one solid tungsten cylinder with a radius of 40 mm and a length
of 150 mm and three polyethylene cylinders with radius of 40 mm and lengths of
550, 700 and 1000 mm. Eight different momenta of the secondary beam (50, 60,
70, 100, 120, 150, 200 and 250 GeV/c) as well as two different physics lists
(QGSP_BIC and FTFP_BERT) have been extensively studied. The purpose of this
study is (a) to optimize (using the appropriate filter target) the particle
production from the secondary targets as demanded by the experiments (b)
investigate the proton production (with respect to the pion production) in the
produced tertiary beams, a fact interesting for cross-section measuring
experiments (e.g. NA61), (c) provide an expected beam-composition database for
each target and energy that will act as a reference for the test-beam users of
the North Area and (d) demonstrate the differences between the different
GEANT-4 physics lists. Moreover this work constitutes a starting point for a
more detailed benchmark of the different available Monte-Carlo models and codes
in this momentum range.


title:
The Solar Twin Planet Search. V. Close-in, low-mass planet candidates
  and evidence of planet accretion in the solar twin HIP 68468

abstract:
  [Methods]. We obtained high-precision radial velocities with HARPS on the ESO
3.6 m telescope and determined precise stellar elemental abundances (~0.01 dex)
using MIKE spectra on the Magellan 6.5m telescope. [Results]. Our data indicate
the presence of a planet with a minimum mass of 26 Earth masses around the
solar twin HIP 68468. The planet is a super-Neptune, but unlike the distant
Neptune in our solar system (30 AU), HIP 68468c is close-in, with a semi-major
axis of 0.66 AU, similar to that of Venus. The data also suggest the presence
of a super-Earth with a minimum mass of 2.9 Earth masses at 0.03 AU; if the
planet is confirmed, it will be the fifth least massive radial velocity planet
discovery to date and the first super-Earth around a solar twin. Both
isochrones (5.9 Gyr) and the abundance ratio [Y/Mg] (6.4 Gyr) indicate an age
of about 6 billion years. The star is enhanced in refractory elements when
compared to the Sun, and the refractory enrichment is even stronger after
corrections for Galactic chemical evolution. We determined a NLTE Li abundance
of 1.52 dex, which is four times higher than what would be expected for the age
of HIP 68468. The older age is also supported by the low log(R'HK) (-5.05) and
low jitter. Engulfment of a rocky planet of 6 Earth masses can explain the
enhancement in both lithium and the refractory elements. [Conclusions]. The
super-Neptune planet candidate is too massive for in situ formation, and
therefore its current location is most likely the result of planet migration
that could also have driven other planets towards its host star, enhancing thus
the abundance of lithium and refractory elements in HIP 68468. The intriguing
evidence of planet accretion warrants further observations to verify the
existence of the planets that are indicated by our data and to better constrain
the nature of the planetary system around this unique star.


title:
Quantum fluctuation theorems and work-energy relationships with due
  regard for convergence, dissipation and irreversibility

abstract:
  Firstly the fluctuation theorems (FT) for expended work in a driven
nonequilibrium system, isolated or thermostatted, together with the ensuing
Jarzynski work-energy (W-E) relationships, will be discussed and reobtained.
Secondly, the fluctuation theorems for entropy flow will be reconsidered. Our
treatment will be fully quantum-statistical, being an ex-tension of our
previous research reported in Phys. Rev. E (2012), and will avoid the
deficiencies that afflicted previous works such as: arguments based on
classical trajectories in phase space, a reliance on the 'pure' von Neumann
equation or 'non-reduced' Heisenberg operators, or other departures from the
general tenets spelled out by Lindblad and others (e.g. Breuer and Petruccione)
such as stochastic 'jump-induced' random trajectories. While a number of
relationships from such previous works will still be employed, our Markov
probability $P(\sigma_f,t_f|\sigma_0,t_0)$ shall only denote the two
state-points, with no reference whatsoever to stochastic trajectories, these
being meaningless in a quantum description.


title:
Landau levels and shallow donor states in GaAs/AlGaAs multiple quantum
  wells at mega-gauss magnetic fields

abstract:
  Landau levels and shallow donor states in multiple GaAs/AlGaAs quantum wells
(MQWs) are investigated by means of the cyclotron resonance at mega-gauss
magnetic fields. Measurements of magneto-optical transitions were performed in
pulsed fields up to 140 T and temperatures from 6 to 300 K. The $14\times14$
\textbf{P}$\cdot$\textbf{p} band model for GaAs is used to interpret
free-electron transitions in a magnetic field. Temperature behavior of the
observed resonant structure indicates, in addition to the free-electron Landau
states, contributions of magneto-donor states in the GaAs wells and possibly in
the AlGaAs barriers. The magneto-donor energies are calculated using a
variational procedure suitable for high magnetic fields and accounting for
conduction band nonparabolicity in GaAs. It is shown that the above states,
including their spin splitting, allow one to interpret the observed
magneto-optical transitions in MQWs in the middle infrared region. Our
experimental and theoretical results at very high magnetic fields are
consistent with the picture used previously for GaAs/AlGaAs MQWs at lower
magnetic fields.


title:
Finite-temperature phase transition in a homogeneous one-dimensional gas
  of attractive bosons

abstract:
  In typical one-dimensional models the Mermin-Wagner theorem forbids long
range order, thus preventing finite-temperature phase transitions. We find a
finite-temperature phase transition for a homogeneous system of attractive
bosons in one dimension. The low-temperature phase is characterized by a
quantum bright soliton without long range order; the high-temperature phase is
a free gas. Numerical calculations for finite particle numbers show a specific
heat scaling as $N^2$, consistent with a vanishing transition region in the
thermodynamic limit.


title:
$\Lambda_c\Sigma_c\pi$ coupling and $\Sigma_c \rightarrow\Lambda_c \pi$
  decay in lattice QCD

abstract:
  We evaluate the $\Lambda_c\Sigma_c\pi$ coupling constant ($G_{\Lambda_c
\Sigma_c \pi}$) and the width of the strong decay $\Sigma_c
\rightarrow\Lambda_c \pi$ in 2+1 flavor lattice QCD on four different ensembles
with pion masses ranging from 700 MeV to 300 MeV. We find $G_{\Lambda_c
\Sigma_c \pi}=18.332(1.476)_{\rm{stat.}}(2.171)_{\rm{syst.}}$ and the decay
width $\Gamma(\Sigma_c \rightarrow\Lambda_c
\pi)=1.65(28)_{\rm{stat.}}(30)_{\rm{syst.}}$~MeV on the physical quark-mass
point, which is in agreement with the recent experimental determination.


title: Orthogonal Random Features

abstract:
  We present an intriguing discovery related to Random Fourier Features: in
Gaussian kernel approximation, replacing the random Gaussian matrix by a
properly scaled random orthogonal matrix significantly decreases kernel
approximation error. We call this technique Orthogonal Random Features (ORF),
and provide theoretical and empirical justification for this behavior.
Motivated by this discovery, we further propose Structured Orthogonal Random
Features (SORF), which uses a class of structured discrete orthogonal matrices
to speed up the computation. The method reduces the time cost from
$\mathcal{O}(d^2)$ to $\mathcal{O}(d \log d)$, where $d$ is the data
dimensionality, with almost no compromise in kernel approximation quality
compared to ORF. Experiments on several datasets verify the effectiveness of
ORF and SORF over the existing methods. We also provide discussions on using
the same type of discrete orthogonal structure for a broader range of
applications.


title:
Latitudinal variability in Jupiter's tropospheric disequilibrium
  species: GeH$_4$, AsH$_3$ and PH$_3$

abstract:
  Jupiter's tropospheric composition is studied using high resolution
spatially-resolved 5-micron observation from the CRIRES instrument at the Very
Large Telescope. The high resolving power (R=96,000) allows us to spectrally
resolve the line shapes of individual molecular species in Jupiter's
troposphere and, by aligning the slit north-south along Jupiter's central
meridian, we are able to search for any latitudinal variability. Despite the
high spectral resolution, we find that there are significant degeneracies
between the cloud structure and aerosol scattering properties that complicate
the retrievals of tropospheric gaseous abundances and limit conclusions on any
belt-zone variability. However, we do find evidence for variability between the
equatorial regions of the planet and the polar regions. Arsine (AsH$_3$) and
phosphine (PH$_3$) both show an enhancement at high latitudes, while the
abundance of germane (GeH$_4$) remains approximately constant. These
observations contrast with the theoretical predictions from Wang et al. (2016)
and we discuss the possible explanations for this difference.


title:
Temperatures are not useful to characterise bright-soliton experiments
  for ultra-cold atoms

abstract:
  Contrary to many other translationally invariant one-dimensional models, the
low-temperature phase for an attractively interacting one-dimensional Bose-gas
(a quantum bright soliton) is stable against thermal fluctuations. However,
treating the thermal properties of quantum bright solitons within the canonical
ensemble leads to anomalous fluctuations of the total energy that indicate that
canonical and micro-canonical ensembles are not equivalent. State-of-the-art
experiments are best described by the micro-canonical ensemble, within which we
predict a co-existence between single atoms and solitons even in the
thermodynamic limit - contrary to strong predictions based on both the Landau
hypothesis and the canonical ensemble. This questions the use of temperatures
to describe state-of-the-art bright soliton experiments that currently load
Bose-Einstein condensates into quasi-one-dimensional wave guides without adding
contact to a heat bath.


title: Missing Data Imputation for Supervised Learning

abstract:
  Missing data imputation can help improve the performance of prediction models
in situations where missing data hide useful information. This paper compares
methods for imputing missing categorical data for supervised classification
tasks. We experiment on two machine learning benchmark datasets with missing
categorical data, comparing classifiers trained on non-imputed (i.e., one-hot
encoded) or imputed data with different levels of additional missing-data
perturbation. We show imputation methods can increase predictive accuracy in
the presence of missing-data perturbation, which can actually improve
prediction accuracy by regularizing the classifier. We achieve the
state-of-the-art on the Adult dataset with missing-data perturbation and
k-nearest-neighbors (k-NN) imputation.


title:
Damping-free collective oscillations of a driven two-component Bose gas
  in optical lattices

abstract:
  We explore quantum many-body physics of a driven Bose-Einstein condensate in
optical lattices. The laser field induces a gap in the generalized Bogoliubov
spectrum proportional to the effective Rabi frequency. The lowest lying modes
in a driven condensate are characterized by zero group velocity and non-zero
current. Thus, the laser field induces roton modes, which carry interaction in
a driven condensate. We show that collective excitations below the energy of
the laser-induced gap remain undamped, while above the gap they are
characterized by a significantly suppressed Landau damping rate.


title: Integrating Topic Models and Latent Factors for Recommendation

abstract:
  Nowadays, we have large amounts of online items in various web-based
applications, which makes it an important task to build effective personalized
recommender systems so as to save users' efforts in information seeking. One of
the most extensively and successfully used methods for personalized
recommendation is the Collaborative Filtering (CF) technique, which makes
recommendation based on users' historical choices as well as those of the
others'. The most popular CF method, like Latent Factor Model (LFM), is to
model how users evaluate items by understanding the hidden dimension or factors
of their opinions. How to model these hidden factors is key to improve the
performance of recommender system. In this work, we consider the problem of
hotel recommendation for travel planning services by integrating the location
information and the user's preference for recommendation. The intuition is that
user preferences may change dynamically over different locations, thus treating
the historical decisions of a user as static or universally applicable can be
infeasible in real-world applications. For example, users may prefer chain
brand hotels with standard configurations when traveling for business, while
they may prefer unique local hotels when traveling for entertainment. In this
paper, we aim to provide trip-level personalization for users in
recommendation.


title: Multibands Tunneling in AAA-Stacked Trilayer Graphene

abstract:
  We study the electronic transport through np and npn junctions for
AAA-stacked trilayer graphene. Two kinds of gates are considered where the
first is a single gate and the second is a double gate. After obtaining the
solutions for the energy spectrum, we use the transfer matrix method to
determine the three transmission probabilities for each individual cone
$\tau=0, \pm 1$. We show that the quasiparticles in AAA-stacked trilayer
graphene are not only chiral but also labeled by an additional cone index
$\tau$. The obtained bands are composed of three Dirac cones that depend on the
chirality indexes. We show that there is perfect transmission for normal or
near normal incidence, which is a manifestation of the Klein tunneling effect.
We analyze also the corresponding total conductance, which is defined as the
sum of the conductance channels in each individual cone. Our results are
numerically discussed and compared with those obtained for ABA- and ABC-stacked
trilayer graphene.


title:
Stability analysis of the numerical Method of characteristics applied to
  a class of energy-preserving systems. Part I: Periodic boundary conditions

abstract:
  We study numerical (in)stability of the Method of characteristics (MoC)
applied to a system of non-dissipative hyperbolic partial differential
equations (PDEs) with periodic boundary conditions. We consider three different
solvers along the characteristics: simple Euler (SE), modified Euler (ME), and
Leap-frog (LF). The two former solvers are well known to exhibit a mild, but
unconditional, numerical instability for non-dissipative ordinary differential
equations (ODEs). They are found to have a similar (or stronger, for the
MoC-ME) instability when applied to non-dissipative PDEs. On the other hand,
the LF solver is known to be stable when applied to non-dissipative ODEs.
However, when applied to non-dissipative PDEs within the MoC framework, it was
found to have by far the strongest instability among all three solvers. We also
comment on the use of the fourth-order Runge--Kutta solver within the MoC
framework.


title:
Stability analysis of the numerical Method of characteristics applied to
  a class of energy-preserving systems. Part II: Nonreflecting boundary
  conditions

abstract:
  We show that imposition of non-periodic, in place of periodic, boundary
conditions (BC) can alter stability of modes in the Method of characteristics
(MoC) employing certain ordinary-differential equation (ODE) numerical solvers.
Thus, using non-periodic BC may render some of the MoC schemes stable for most
practical computations, even though they are unstable for periodic BC. This
fact contradicts a statement, found in some literature, that an instability
detected by the von Neumann analysis for a given numerical scheme implies an
instability of that scheme with arbitrary (i.e., non-periodic) BC. We explain
the mechanism behind this contradiction. We also show that, and explain why,
for the MoC employing some other ODE solvers, stability of the modes may be
unaffected by the BC.


title:
An inductive machinery for representations of categories with shift
  functors

abstract:
  We describe an inductive machinery to prove various properties of
representations of a category equipped with a generic shift functor.
Specifically, we show that if a property (P) of representations of the category
behaves well under the generic shift functor, then all finitely generated
representations of the category have the property (P). In this way, we obtain
simple criteria for properties such as Noetherianity, finiteness of
Castelnuovo-Mumford regularity, and polynomial growth of dimension to hold.
This gives a systemetic and uniform proof of such properties for
representations of the categories $\FI_G$ and $\OI_G$ which appear in
representation stability theory.


title: A Study of the Gamma-Ray Burst Fundamental Plane

abstract:
  A class of long gamma-ray bursts (GRBs) with a plateau phase in their X-ray
afterglows obeys a three-dimensional (3D) relation (Dainotti et al. 2016),
between the rest-frame time at the end of the plateau, Ta, its corresponding
X-ray luminosity, La, and the peak luminosity in the prompt emission, Lpeak. We
extended the original analysis with X-ray data from July 2014 to July 2016
achieving a total sample of 183 Swift GRBs with afterglow plateaus and known
redshifts. We added the most recent GRBs to the previous 'gold sample' (now
including 45 GRBs) and obtained a relation plane with intrinsic scatter
compatible within one sigma with the previous result. We compared several GRB
categories, such as short with extended emission, X-ray Flashes, GRBs
associated with SNe, long-duration GRBs, and the gold sample, composed only by
GRBs with light curves with good data coverage and relatively flat plateaus and
evaluated their relation planes. We found that they are not statistically
different from the fundamental plane derived from the gold sample and that the
fundamental plane still has the smallest scatter. We compared the jet opening
angles tabulated in literature with the angles derived using the Eiso-Egamma
relation of the method in Pescalli et al. (2015) and calculated the relation
plane for a sample of long GRBs accounting for the different jet opening
angles. We observed that this correction does not significantly reduce the
scatter. In an extended analysis, we found that the fundamental plane is
independent from several prompt and afterglow parameters.


title: SOL: A Library for Scalable Online Learning Algorithms

abstract:
  SOL is an open-source library for scalable online learning algorithms, and is
particularly suitable for learning with high-dimensional data. The library
provides a family of regular and sparse online learning algorithms for
large-scale binary and multi-class classification tasks with high efficiency,
scalability, portability, and extensibility. SOL was implemented in C++, and
provided with a collection of easy-to-use command-line tools, python wrappers
and library calls for users and developers, as well as comprehensive documents
for both beginners and advanced users. SOL is not only a practical machine
learning toolbox, but also a comprehensive experimental platform for online
learning research. Experiments demonstrate that SOL is highly efficient and
scalable for large-scale machine learning with high-dimensional data.


title: On prime vs. prime power pairs

abstract:
  In this paper, we consider pairs of a prime and a prime power with a fixed
difference. We prove an average result on the distribution of such pairs. This
is a partial improvement of the result of Bauer (1998).


title:
On the difference between locally risk-minimizing and delta hedging
  strategies for exponential L\'evy models

abstract:
  We discuss the difference between locally risk-minimizing and delta hedging
strategies for exponential L\'evy models, where delta hedging strategies in
this paper are defined under the minimal martingale measure. We give firstly
model-independent upper estimations for the difference. In addition we show
numerical examples for two typical exponential L\'evy models: Merton models and
variance gamma models.


title: A Novel Route to Reach a $p$-wave Superfluid Fermi Gas

abstract:
  We theoretically propose an idea to realize a $p$-wave superfluid Fermi gas.
To overcome the experimental difficulty that a $p$-wave pairing interaction to
form $p$-wave Cooper pairs damages the system before the condensation growth,
we first prepare a $p$-wave pair amplitude ($\Phi_{p}$) in a spin-orbit coupled
$s$-wave superfluid Fermi gas, without any $p$-wave interaction. Then, by
suddenly changing the $s$-wave interaction with a $p$-wave one ($U_{p}$) by
using a Feshbach resonance, we reach the $p$-wave superfluid phase with the
$p$-wave order parameter being symbolically written as $\Delta_{p}\sim
U_{p}\Phi_{p}$. In this letter, we assess this scenario within the framework of
a time-dependent Bogoliubov-de Gennes theory. Our results would contribute to
the study toward the realization of unconventional pairing states in an
ultracold Fermi gas.


title: Recent advances in content based video copy detection

abstract:
  With the immense number of videos being uploaded to the video sharing sites,
issue of copyright infringement arises with uploading of illicit copies or
transformed versions of original video. Thus safeguarding copyright of digital
media has become matter of concern. To address this concern, it is obliged to
have a video copy detection system which is sufficiently robust to detect these
transformed videos with ability to pinpoint location of copied segments. This
paper outlines recent advancement in content based video copy detection, mainly
focusing on different visual features employed by video copy detection systems.
Finally we evaluate performance of existing video copy detection systems.


title:
Anomalous phase transitions in one-dimensional organo-metal halide
  perovskite nanorods grown inside porous silicon nanotube templates

abstract:
  One-dimensional organo-metal halide Perovskite (CH3NH3PbI3) nanorods whose
diameter and length are dictated by the inner size of porous silicon nanotube
templates have been grown, characterized and compared to bulk perovskites in
the form of microwires. We have observed a structural phase transition for bulk
perovskites, where the crystal structure changes from tetragonal to
orthorhombic at about 150K, as opposed to small diameter one-dimensional
perovskite nanorods, of the order of 30-70 nm in diameter, where the phase
transition is inhibited and the dominant phase remains tetragonal. Two major
experimental techniques, infrared absorption spectroscopy and
photoluminescence, were utilized to probe the temperature dependence of the
perovskite phases over the 4-300K temperature range. Yet, different
characteristics of the phase transition were measured by the two spectroscopic
methods and explained by the presence of small, tetragonal inclusions embedded
in the orthorhombic phase. The inhibition of the phase transition is attributed
to the large surface area of these one-dimensional perovskite nanorods, which
gives rise to a large stress that, in turn, prevents the formation of the
orthorhombic phase. The absence of phase transition enables the measurement of
the tetragonal bandgap energy down to low temperatures.


title: The Dynamic Descriptive Complexity of k-Clique

abstract:
  In this work the dynamic descriptive complexity of the k-clique query is
studied. It is shown that when edges may only be inserted then k-clique can be
maintained by a quantifier-free update program of arity k-1, but it cannot be
maintained by a quantifier-free update program of arity k-2 (even in the
presence of unary auxiliary functions). This establishes an arity hierarchy for
graph queries for quantifier-free update programs under insertions. The proof
of the lower bound uses upper and lower bounds for Ramsey numbers.


title:
Phenomenological study of extended seesaw model for light sterile
  neutrino

abstract:
  We study the zero textures of the Yukawa matrices in the minimal extended
type-I seesaw (MES) model which can give rise to $\sim$ eV scale sterile
neutrinos. In this model, three right handed neutrinos and one extra singlet
$S$ are added to generate a light sterile neutrino. The light neutrino mass
matrix for the active neutrinos, $ m_{\nu}$, depends on the Dirac neutrino mass
matrix ($ M_{D} $), Majorana neutrino mass matrix ($ M_{R} $) and the mass
matrix ($ M_{S} $) coupling the right handed neutrinos and the singlet. The
model predicts one of the light neutrino masses to vanish. We systematically
investigate the zero textures in $ M_{D} $ and observe that maximum five zeros
in $ M_{D} $ can lead to viable zero textures in $ m_{\nu} $. For this study we
consider four different forms for $ M_R $ (one diagonal and three off diagonal)
and two different forms of $(M_{S})$ containing one zero. Remarkably we obtain
only two allowed forms of $ m_{\nu} $ ($m_{e\tau} = 0 $ and $m_{\tau\tau}=0$)
having inverted hierarchical mass spectrum. We re-analyze the phenomenological
implications of these two allowed textures of $m_\nu$ in the light of recent
neutrino oscillation data. In the context of the MES model, we also express the
low energy mass matrix, the mass of the sterile neutrino and the active-sterile
mixing in terms of the parameters of the allowed Yukawa matrices. The MES model
leads to some extra correlations which disallow some of the Yukawa textures
obtained earlier, even though they give allowed one-zero forms of $m_\nu$. We
show that the allowed textures in our study can be realized in a simple way in
a model based on MES mechanism with a discrete Abelian flavor symmetry group
$Z_8 \times Z_2$.


title: Representation Learning Models for Entity Search

abstract:
  We focus on the problem of learning distributed representations for entity
search queries, named entities, and their short descriptions. With our
representation learning models, the entity search query, named entity and
description can be represented as low-dimensional vectors. Our goal is to
develop a simple but effective model that can make the distributed
representations of query related entities similar to the query in the vector
space. Hence, we propose three kinds of learning strategies, and the difference
between them mainly lies in how to deal with the relationship between an entity
and its description. We analyze the strengths and weaknesses of each learning
strategy and validate our methods on public datasets which contain four kinds
of named entities, i.e., movies, TV shows, restaurants and celebrities. The
experimental results indicate that our proposed methods can adapt to different
types of entity search queries, and outperform the current state-of-the-art
methods based on keyword matching and vanilla word2vec models. Besides, the
proposed methods can be trained fast and be easily extended to other similar
tasks.


title:
Seeding the m = 0 instability in dense plasma focus Z-pinches with a
  hollow anode

abstract:
  The dense plasma focus (DPF) is a classic Z-pinch plasma device that has been
studied for decades as a radiation source. The formation of the m = 0 plasma
instability during the compression phase is linked to the generation of
high-energy charged particle beams, which, when operated in deuterium, lead to
beam-target fusion reactions and the generation of neutron yield. In this
paper, we present a technique of seeding the m = 0 instability by employing a
hollow in the anode. As the plasma sheath moves along the anode's hollow
structure, a low density perturbation is formed and this creates a non-uniform
plasma column which is highly unstable. Dynamics of the low density
perturbation and preferential seeding of the m = 0 instability were studied in
detail with fully kinetic plasma simulations performed in the Large Scale
Plasma particle-in-cell code as well as with a simple snowplow model. The
simulations showed that by employing an anode geometry with appropriate inner
hollow radius, the neutron yield of the DPF is significantly improved and
low-yield shots are eliminated.


title: More on foxes

abstract:
  An edge in a $k$-connected graph $G$ is called {\em $k$-contractible} if the
graph $G/e$ obtained from $G$ by contracting $e$ is $k$-connected. Generalizing
earlier results on $3$-contractible edges in spanning trees of $3$-connected
graphs, we prove that (except for the graphs $K_{k+1}$ if $k \in \{1,2\}$) (a)
every spanning tree of a $k$-connected triangle free graph has two
$k$-contractible edges, (b) every spanning tree of a $k$-connected graph of
minimum degree at least $\frac{3}{2}k-1$ has two $k$-contractible edges, (c)
for $k>3$, every DFS tree of a $k$-connected graph of minimum degree at least
$\frac{3}{2}k-\frac{3}{2}$ has two $k$-contractible edges, (d) every spanning
tree of a cubic $3$-connected graph nonisomorphic to $K_4$ has at least
$\frac{1}{3}|V(G)|-1$ many $3$-contractible edges, and (e) every DFS tree of a
$3$-connected graph nonisomorphic to $K_4$, the prism, or the prism plus a
single edge has two 3-contractible edges. We also discuss in which sense these
theorems are best possible.


title:
An Algorithm for the calculation of non-isotropic collision integral
  matrix elements of the non-linear Boltzmann equation by the use of recurrence
  relations

abstract:
  An algorithm for sequential calculation of non-isotropic matrix elements of
the collision integral which are necessary for the solution of the non-linear
Boltzmann equation by moment method is proposed. Isotropic matrix elements that
we believe are known, are starting ones. The procedure is valid for any
interaction law and any mass ratio of the colliding particles.


title: Universal dimer-dimer scattering in lattice effective field theory

abstract:
  We consider two-component fermions with short-range interactions and large
scattering length. This system has universal properties that are realized in
several different fields of physics. In the limit of large fermion-fermion
scattering length $a_\mathrm{ff}$ and zero-range interaction, all properties of
the system scale proportionally with $a_\mathrm{ff}$. For the case with shallow
bound dimers, we calculate the dimer-dimer scattering phase shifts using
lattice effective field theory. We extract the universal dimer-dimer scattering
length $a_\mathrm{dd}/a_\mathrm{ff}=0.618(30)$ and effective range
$r_\mathrm{dd}/a_\mathrm{ff}=-0.431(48)$. This result for the effective range
is the first calculation with quantified and controlled systematic errors. We
also benchmark our methods by computing the fermion-dimer scattering parameters
and testing some predictions of conformal scaling of irrelevant operators near
the unitarity limit.

categories: nucl-th cond-mat.quant-gas hep-lat physics.atom-ph


title: Laser assisted electron dynamics

abstract:
  We apply the convergent close-coupling (CCC) formalism to analyse the
processes of laser assisted electron impact ionisation of He, and the
attosecond time delay in the photodetachment of the H^{-} ion and the
photoionisation of He. Such time dependent atomic collision processes are of
considerable interest as experimental measurements on the relevant timescale
(attoseconds 10^{-18} s) are now possible utilising ultrafast and intense laser
pulses. These processes in particular are furthermore of interest as they are
strongly influenced by many-electron correlations. In such cases their
theoretical description requires a more comprehensive treatment than that
offered by first order perturbation theory. We apply such a treatment through
the use of the CCC formalism which involves the complete numeric solution of
the integral Lippmann-Schwinger equations pertaining to a particular scattering
event. For laser assisted electron impact ionisation of He such a treatment is
of a considerably greater accuracy than the majority of previous theoretical
descriptions applied to this problem which treat the field-free scattering
event within the first Born approximation. For the photodetachment of H^{-} and
photoionisation of He, the CCC approach allows for accurate calculation of the
attosecond time delay and comparison with the companion processes of
photoelectron scattering on H and He^{+}, respectively.


title: Generative complexity of Gray-Scott model

abstract:
  In the Gray-Scott reaction-diffusion system one reactant is constantly fed in
the system, another reactant is reproduced by consuming the supplied reactant
and also converted to an inert product. The rate of feeding one reactant in the
system and the rate of removing another reactant from the system determine
configurations of concentration profiles: stripes, spots, waves. We calculate
the generative complexity --- a morphological complexity of concentration
profiles grown from a point-wise perturbation of the medium --- of the
Gray-Scott system for a range of the feeding and removal rates. The
morphological complexity is evaluated using Shannon entropy, Simpson diversity,
approximation of Lempel-Ziv complexity, and expressivity (Shannon entropy
divided by space-filling). We analyse behaviour of the systems with highest
values of the generative morphological complexity and show that the Gray-Scott
systems expressing highest levels of the complexity are composed of the
wave-fragments (similar to wave-fragments in sub-excitable media) and
travelling localisations (similar to quasi-dissipative solitons and gliders in
Conway's Game of Life).


title:
Conclusions about properties of high-energy cosmic-rays drawn with
  limited recourse to hadronic models

abstract:
  Determining the energy and mass of the highest energy cosmic rays requires
knowledge of features of particle interactions at energies beyond those reached
at the LHC. Inadequacies of the model predictions set against a variety of data
are summarised and it is clear that firm statements about primary mass are
premature. Nonetheless, conclusions of significance about the origin of the
highest-energy cosmic rays can be deduced from the data. This paper is
dedicated to my great friend and colleague, Jim Cronin, who died suddenly on 25
August 2016, without whom the Auger Collaboration would not have happened.


title:
An instability mechanism of pulsatile flow along particle trajectories
  for the axisymmetric Euler equations

abstract:
  The dynamics along the particle trajectories for the 3D axisymmetric Euler
equations in an infinite cylinder are considered. It is shown that if the
inflow-outflow is rapidly increasing in time, the corresponding laminar profile
of the Euler flow is not (in some sense) stable provided that the swirling
component is not small. This exhibits an instability mechanism of pulsatile
flow. In the proof, Frenet-Serret formulas and orthonormal moving frame are
essentially used.


title:
Thermal structures of accreting neutron stars with neutrino losses due
  to strong pion condensations

abstract:
  Quiescent X-ray luminosities are presented in low mass X-ray binaries with
use of evolutionary calculations. The calculated luminosities are compared with
observed ones in terms of timeaveraged mass accretion rate. It is shown that
neutrino emission by strong pion condensation can explain quiescent X-ray
luminosity of SAX J1808.4-3658 and we do not need direct Urca processes
concerning nucleons and/or hyperons.


title: Added costs of insect-scale flapping flight in unsteady airflows

abstract:
  The aerial environment in the operating domain of small-scale natural and
artificial flapping wing fliers is highly complex, unsteady and generally
turbulent. Considering flapping flight in an unsteady wind environment with a
periodically varying lateral velocity component, we show that body rotations
experienced by flapping wing fliers result in the reorientation of the
aerodynamic force vector that can render a substantial cumulative deficit in
the vertical force. We derive quantitative estimates of the body roll amplitude
and the related energetic requirements to maintain the weight support in free
flight under such conditions. We conduct force measurements of a miniature
hummingbird-inspired robotic flapper and numerical simulations of a bumblebee.
In both cases, we demonstrate the loss of weight support due to body roll
rotations. Using semi-restrained flight measurements, we demonstrate the
increased power requirements to maintain altitude in unsteady winds, achieved
by increasing the flapping frequency. Flapping fliers may increase their
flapping frequency as well as the stroke amplitude to produce the required
increase in aerodynamic force, both of these two types of compensatory control
requiring additional energetic cost. We analyze the existing data from
experiments on animals flying in von K\'arm\'an streets and find reasonable
agreement with the proposed theoretical model.


title: Weak Localization in Electric-Double-Layer Gated Few-layer Graphene

abstract:
  We induce surface carrier densities up to $\sim7\cdot 10^{14}$cm$^{-2}$ in
few-layer graphene devices by electric double layer gating with a polymeric
electrolyte. In 3-, 4- and 5-layer graphene below 20-30K we observe a
logarithmic upturn of resistance that we attribute to weak localization in the
diffusive regime. By studying this effect as a function of carrier density and
with ab-initio calculations we derive the dependence of transport, intervalley
and phase coherence scattering lifetimes on total carrier density. We find that
electron-electron scattering in the Nyquist regime is the main source of
dephasing at temperatures lower than 30K in the $\sim10^{13}$cm$^{-2}$ to
$\sim7 \cdot 10^{14}$cm$^{-2}$ range of carrier densities. With the increase of
gate voltage, transport elastic scattering is dominated by the competing
effects due to the increase in both carrier density and charged scattering
centers at the surface. We also tune our devices into a crossover regime
between weak and strong localization, indicating that simultaneous tunability
of both carrier and defect density at the surface of electric double layer
gated materials is possible.


title:
Differential models for B-type open-closed topological Landau-Ginzburg
  theories

abstract:
  We propose a family of differential models for B-type open-closed topological
Landau-Ginzburg theories defined by a pair $(X,W)$, where $X$ is any
non-compact Calabi-Yau manifold and $W$ is any holomorphic complex-valued
function defined on $X$ whose critical set is compact. The models are
constructed at cochain level using smooth data, including the twisted Dolbeault
algebra of polyvector valued forms and a twisted Dolbeault category of
holomorphic factorizations of $W$. We give explicit proposals for cochain level
versions of the bulk and boundary traces and for the bulk-boundary and
boundary-bulk maps of the Landau-Ginzburg theory. We prove that most of the
axioms of an open-closed topological field theory are satisfied on cohomology
and conjecture that the remaining axioms are also satisfied.


title:
On the ions acceleration via collisionless magnetic reconnection in
  laboratory plasmas

abstract:
  This work presents an analysis of the ion outflow from magnetic reconnection
throughout fully kinetic simulations with typical laboratory plasmas values. A
symmetric initial configuration for the density and magnetic field is
considered across the current sheet. After analyzing the behavior of a set of
nine simulations with a reduced mass ratio and with a permuted value of three
initial electron temperature and magnetic field intensity, the best ion
acceleration scenario is further studied with a realistic mass ratio in terms
of the ion dynamics and energy budget. Interestingly, a series of shock waves
structures are observed in the outflow, resembling the shock discontinuities
found in recent magnetohydrodynamic (MHD) simulations. An analysis of the ion
outflow at several distances from the reconnection point is presented, in light
of possible laboratory applications. The analysis suggests that magnetic
reconnection could be used as a tool for plasma acceleration, with applications
ranging from electric propulsion to production of ion thermal beams.


title:
Keldysh approach to periodically driven systems with a fermionic bath:
  non-equilibrium steady state, proximity effect and dissipation

abstract:
  We study properties of a periodically driven system coupled to a thermal
bath. As a nontrivial example, we consider periodically driven metallic system
coupled to a superconducting bath. The effect of the superconductor on the
driven system is two-fold: it (a) modifies density of states in the metal via
the proximity effect and (b) acts as a thermal bath for light-excited
quasi-particles. Using Keldysh formalism, we calculate, nonpertubatively in the
system-bath coupling, the steady-state properties of the system and obtain
non-equilibrium distribution function. The latter allows one to calculate
observable quantities which can be spectroscopically measured in tunneling
experiments.


title:
The Conditional Variational Principle for Maps with the Pseudo-orbit
  Tracing Property

abstract:
  Let $(X,d,f)$ be a topological dynamical system, where $(X,d)$ is a compact
metric space and $f:X\to X$ is a continuous map. We define $n$-ordered
empirical measure of $x\in X$ by \begin{align*}
\mathscr{E}_n(x)=\frac{1}{n}\sum\limits_{i=0}^{n-1}\delta_{f^ix}, \end{align*}
where $\delta_y$ is the Dirac mass at $y$. Denote by $V(x)$ the set of limit
measures of the sequence of measures $\mathscr{E}_n(x).$ In this paper, we
obtain conditional variational principles for the topological entropy of
\begin{align*} \Delta_{sub}(I)=\left\{x\in X:V(x)\subset I\right\},
\end{align*} and \begin{align*} \Delta_{cap}(I)=\left\{x\in X:V(x)\cap
I\neq\emptyset \right\}. \end{align*} in a transitive dynamical system with the
pseudo-orbit tracing property, where $I$ is a certain subset of $\mathscr
M_{\rm inv}(X,f)$.


title:
Pro-unipotent harmonic actions and dynamical properties of $p$-adic
  cyclotomic multiple zeta values

abstract:
  $p$-adic cyclotomic multiple zeta values depend on the choice of a number of
iterations of the crystalline Frobenius of the pro-unipotent fundamental
groupoid of $\mathbb{P}^{1} - \{0,\mu_{N},\infty\}$. In this paper we study how
the iterated Frobenius depends on the number of iterations, in relation with
the computation of $p$-adic cyclotomic multiple zeta values in terms of
cyclotomic multiple harmonic sums. This provides new results on that
computation and the definition of a new pro-unipotent harmonic action.


title:
How well do Network Models predict Observations? On the Importance of
  Predictability in Network Models

abstract:
  Network models are an increasingly popular way to abstract complex
psychological phenomena. While the study of the structure of network models has
led to many important insights, little attention is paid to how well they
predict observations. This is despite the fact that predictability is crucial
for judging the practical relevance of edges: for instance in clinical
practice, predictability of a symptom indicates whether a an intervention on
that symptom through the symptom network is promising. We close this
methodological gap by introducing nodewise predictability, which quantifies how
well a given node can be predicted by all other nodes it is connected to in the
network. In addition, we provide fully reproducible code examples of how to
compute and visualize nodewise predictability both for cross-sectional and
time-series data.


title: Improved Classification Rates under Refined Margin Conditions

abstract:
  In this paper we present a simple partitioning based technique to refine the
statistical analysis of classification algorithms. The core of our idea is to
divide the input space into two parts such that the first part contains a
suitable vicinity around the decision boundary, while the second part is
sufficiently far away from the decision boundary. Using a set of margin
conditions we are then able to control the classification error on both parts
separately. By balancing out these two error terms we obtain a refined error
analysis in a final step. We apply this general idea to the histogram rule and
show that even for this simple method we obtain, under certain assumptions,
better rates than the ones known for support vector machines, for certain
plug-in classifiers, and for a recently analyzed tree based
adaptive-partitioning ansatz. Moreover, we show that a margin condition which
sets the critical noise in relation to the decision boundary makes it possible
to improve the optimal rates proven for distributions without this margin
condition.


title: $f$-Divergence Inequalities via Functional Domination

abstract:
  This paper considers derivation of $f$-divergence inequalities via the
approach of functional domination. Bounds on an $f$-divergence based on one or
several other $f$-divergences are introduced, dealing with pairs of probability
measures defined on arbitrary alphabets. In addition, a variety of bounds are
shown to hold under boundedness assumptions on the relative information. The
journal paper, which includes more approaches for the derivation of
f-divergence inequalities and proofs, is available on the arXiv at
https://arxiv.org/abs/1508.00335, and it has been published in the IEEE Trans.
on Information Theory, vol. 62, no. 11, pp. 5973-6006, November 2016.

categories: cs.IT cs.LG math.IT math.PR math.ST stat.TH


title:
Emergence of Non-Axisymmetric Vortex in Strong-Coupling Chiral p-Wave
  Superconductor

abstract:
  We studied strong-coupling effect upon an isolated vortex in a
two-dimensional chiral p-wave superconductor. We solved the Eilenberger
equation for the quasiclassical Green's functions and the Eliashberg equation
with single mode Einstein boson self-consistently. We calculated the
free-energy of each obtained vortex, and found that a non-axisymmetric vortex
metastably exists in some situation.


title: Decentralized Clustering and Linking by Networked Agents

abstract:
  We consider the problem of decentralized clustering and estimation over
multi-task networks, where agents infer and track different models of interest.
The agents do not know beforehand which model is generating their own data.
They also do not know which agents in their neighborhood belong to the same
cluster. We propose a decentralized clustering algorithm aimed at identifying
and forming clusters of agents of similar objectives, and at guiding
cooperation to enhance the inference performance. One key feature of the
proposed technique is the integration of the learning and clustering tasks into
a single strategy. We analyze the performance of the procedure and show that
the error probabilities of types I and II decay exponentially to zero with the
step-size parameter. While links between agents following different objectives
are ignored in the clustering process, we nevertheless show how to exploit
these links to relay critical information across the network for enhanced
performance. Simulation results illustrate the performance of the proposed
method in comparison to other useful techniques.


title:
Importance of local exact exchange potential in hybrid functionals for
  accurate excited states

abstract:
  Density functional theory has been an essential analysis tool for both
theoretical and experimental chemists since accurate hybrid functionals were
developed. Here we propose a local hybrid method derived from the optimized
effective potential (OEP) method and compare its distinct features with
conventional nonlocal ones from the Hartree-Fock (HF) exchange operator. Both
are formally exact for ground states and thus show similar accuracy for
atomization energies and reaction barrier heights. For excited states, the
local version yields virtual orbitals with N-electron character, while those of
the nonlocal version have mixed characters between N- and (N+1)-electron
orbitals. As a result, the orbital energy gaps from the former well approximate
excitation energies with a small mean absolute error (MAE = 0.40 eV) for the
Caricato benchmark set. The correction from time-dependent density functional
theory with a simple local density approximation kernel further improves its
accuracy by incorporating multi-configurational effects, resulting in the total
MAE of 0.27 eV that outperforms conventional functionals except for MN15.


title: Majority problems of large query size

abstract:
  We study two models of the Majority problem. We are given n balls and an
unknown coloring of them with two colors. We can ask sets of balls of size k as
queries, and in the so-called General Model the answer to a query shows if all
the balls in the set are of the same color or not. In the so-called Counting
Model the answer to a query gives the difference between the cardinalities of
the color classes in the query. Our goal is to show a ball of the larger color
class, or prove that the color classes are of the same size, using as few
queries as possible. In this paper we improve the bounds given by De Marco and
Kranakis for the number of queries needed.


title: Infinite transitivity and special automorphisms

abstract:
  It is known that if the special automorphism group $\text{SAut}(X)$ of a
quasiaffine variety $X$ of dimension at least $2$ acts transitively on $X$,
then this action is infinitely transitive. In this paper we address the
question whether this is the only possibility for the automorphism group
$\text{Aut}(X)$ to act infinitely transitively on $X$. We show that this is the
case provided $X$ admits a nontrivial $\mathbb{G}_a$- or $\mathbb{G}_m$-action.
Moreover, 2-transitivity of the automorphism group implies infinite
transitivity.


title:
Pseudogap phenomena near the BKT transition of a two-dimensional
  ultracold Fermi gas in the crossover region

abstract:
  We investigate strong-coupling properties of a two-dimensional ultracold
Fermi gas in the normal phase. In the three-dimensional case, it has been shown
that the so-called pseudogap phenomena can be well described by a
(non-self-consistent) $T$-matrix approximation (TMA). In the two-dimensional
case, while this strong coupling theory can explain the pseudogap phenomenon in
the strong-coupling regime, it unphysically gives large pseudogap size in the
crossover region, as well as in the weak-coupling regime. We show that this
difficulty can be overcome when one improve TMA to include higher order pairing
fluctuations within the framework of a self-consistent $T$-matrix approximation
(SCTMA). The essence of this improvement is also explained. Since the
observation of the BKT transition has recently been reported in a
two-dimensional $^6$Li Fermi gas, our results would be useful for the study of
strong-coupling physics associated with this quasi-long-range order.


title: Cover Systems for the Modalities of Linear Logic

abstract:
  Ono's modal FL-algebras are models of an extension of Full Lambek logic that
has the modalities ! and ? of linear logic. Here we define a notion of modal
FL-cover system that combines aspects of Beth-Kripke-Joyal semantics with
Girard's interpretation of the ! modality, and has structured subsets that
interpret propositions. We show that any modal FL-algebra can be represented as
an algebra of propositions of some modal FL-cover system.


title:
Thermal properties of an impurity immersed in a granular gas of rough
  hard spheres

abstract:
  We study in this work the dynamics of a granular impurity immersed in a
low-density granular gas of identical particles. For description of the
kinetics of the granular gas and the impurity particles we use the rough hard
sphere collisional model. We take into account the effects of non-conservation
of energy upon particle collision. We find an (approximate) analytical solution
of the pertinent kinetic equations for the single-particle velocity
distribution functions that reproduces reasonably well the properties of
translational/rotational energy non-equipartition. We assess the accuracy of
the theoretical solution by comparing with computer simulations. For this, we
use two independent computer data sets, from molecular dynamics (MD) and from
Direct Simulation Monte Carlo method (DSMC). Both approach well, with different
degrees, the kinetic theory within a reasonable range of parameter values.


title:
Some exact solutions of the local induction equation for motion of a
  vortex in a Bose-Einstein condensate with Gaussian density profile

abstract:
  The dynamics of a vortex filament in a trapped Bose-Einstein condensate is
considered when the equilibrium density of the condensate, in rotating with
angular velocity ${\bf\Omega}$ coordinate system, is Gaussian with a quadratic
form ${\bf r}\cdot\hat D{\bf r}$. It is shown that equation of motion of the
filament in the local induction approximation admits a class of exact solutions
in the form of a straight moving vortex, ${\bf R}(\beta,t)=\beta {\bf M}(t)
+{\bf N}(t)$, where $\beta$ is a longitudinal parameter, and $t$ is the time.
The vortex is in touch with an ellipsoid, as it follows from the conservation
laws ${\bf N}\cdot \hat D {\bf N}=C_1$ and ${\bf M}\cdot \hat D {\bf N}=C_0=0$.
Equation of motion for the tangent vector ${\bf M}(t)$ turns out to be closed,
and it has the integrals ${\bf M}\cdot \hat D {\bf M}=C_2$, $(|{\bf M}| -{\bf
M}\cdot\hat G{\bf \Omega})=C$, where the matrix $\hat G=2(\hat I \mbox{Tr\,}
\hat D -\hat D)^{-1}$. Intersection of the corresponding level surfaces
determines trajectories in the phase space.


title: Scalar-tensor linear inflation

abstract:
  We investigate two approaches to non minimally coupled gravity theories which
present linear inflation as attractor solution: a) the scalar-tensor theory
approach, where we look for a scalar-tensor theory that would restore results
of linear inflation in the strong coupling limit for any form of the
non-minimal coupling to gravity of the form of $f(\varphi)R/2$; b) the particle
physics approach, where we motivate the form of the Jordan frame potential by
the loop corrections to the inflaton field. In both cases the Jordan frame
potentials are modifications of the induced inflation, but instead of the
Starobinsky attractor they lead to the linear inflation in the strong coupling
limit.


title:
Interferometric Monitoring of Gamma-ray Bright AGNs I: Results of
  Single-epoch Multifrequency Observations

abstract:
  We present results of single-epoch very long baseline interferometry (VLBI)
observations of gamma-ray bright active galactic nuclei (AGNs) using the Korean
VLBI Network (KVN) at 22, 43, 86, and 129~GHz bands, which are part of a KVN
key science program, Interferometric Monitoring of Gamma-ray Bright AGNs
(iMOGABA). We selected a total of 34 radio-loud AGNs of which 30 sources are
gamma-ray bright AGNs with flux densities of
$>6\times10^{-10}$~ph~cm$^{-2}$~s$^{-1}$. Single-epoch multi-frequency VLBI
observations of the target sources were conducted during a 24-hr session on
2013 November 19 and 20. All observed sources were detected and imaged at all
frequency bands with or without a frequency phase transfer technique which
enabled the imaging of 12 faint sources at 129~GHz, except for one source. Many
of the target sources are resolved on milliarcsecond scales, yielding a
core-jet structure with the VLBI core dominating the synchrotron emission on
the milliarcsecond scale. CLEAN flux densities of the target sources are
0.43-28~Jy, 0.32-21~Jy, 0.18-11~Jy, and 0.35-8.0~Jy in the 22, 43, 86, and
129~GHz bands, respectively.


title:
Calculation of the astrophysical S-factor S_12 with the Lorentz integral
  transform

abstract:
  The LIT approach is tested for the calculation of astrophysical S-factors. As
an example the S-factor of the reaction 2H(p,gamma)3He is considered. It is
discussed that a sufficiently high density of LIT states at low energies is
necessary for a precise determination of S-factors. In particular it is shown
that the hyperspherical basis is not very well suited for such a calculation
and that a different basis system is much more advantageous. A comparison of
LIT results with calculations, where continuum wave functions are explicitly
used, shows that the LIT approach leads to reliable results. It is also shown
how an error estimate of the LIT inversion can be obtained.


title: The Weak Convergence of TCP Bandwidth Sharing

abstract:
  TCP is the dominating transmission protocol in the Internet since decades. It
proved its flexibility to adapt to unknown and changing network conditions. A
distinguished TCP feature is the comparably fair resource sharing.
Unfortunately, this abstract fairness is frequently misinterpreted as
convergence towards equal sharing rates. In this paper we show in theory as
well as in experiment that TCP rate convergence does not exist. Instead, the
individual TCP flow rate is persistently fluctuating over a range close to one
order of magnitude. The fluctuations are not short term but correlated over
long intervals, so that the carried data volume converges rather slowly. The
weak convergence does not negate fairness in general. Nevertheless, a
particular transmission operation could deviate considerably.


title:
Model-independent pricing with insider information: a Skorokhod
  embedding approach

abstract:
  In this paper, we consider the pricing and hedging of a financial derivative
for an insider trader, in a model-independent setting. In particular, we
suppose that the insider wants to act in a way which is independent of any
modelling assumptions, but that she observes market information in the form of
the prices of vanilla call options on the asset. We also assume that both the
insider's information, which takes the form of a set of impossible paths, and
the payoff of the derivative are time-invariant. This setup allows us to adapt
recent work of Beiglboeck, Cox and Huesmann (2016) to prove duality results and
a monotonicity principle, which enables us to determine geometric properties of
the optimal models. Moreover, we show that this setup is powerful, in that we
are able to find analytic and numerical solutions to certain pricing and
hedging problems.


title: Young star clusters in circumnuclear starburst rings

abstract:
  We analyse the cluster luminosity functions (CLFs) of the youngest star
clusters in three galaxies exhibiting prominent circumnuclear starburst rings.
We focus specifically on NGC 1512 and NGC 6951, for which we have access to
H$\alpha$ data that allow us to unambiguously identify the youngest sample
clusters. To place our results on a firm statistical footing, we first explore
in detail a number of important technical issues affecting the process from
converting the observational data into the spectral-energy distributions of the
objects in our final catalogues. The CLFs of the young clusters in both
galaxies exhibit approximate power-law behaviour down to the 90 per cent
observational completeness limits, thus showing that star cluster formation in
the violent environments of starburst rings appears to proceed similarly as
that elsewhere in the local Universe. We discuss this result in the context of
the density of the interstellar medium in our starburst-ring galaxies.


title: Experimental and theoretical study of metal combustion in oxygen flows

abstract:
  The effects of oxygen flow speed and pressure on the iron and mild steel
combustion are investigated experimentally and theoretically. The studied
specimens are vertical cylindrical rods subjected to an axial oxygen flow and
ignited at the upper end by laser irradiation. Three main stages of the
combustion process have been identified experimentally: (1) Induction period,
during which the rod is heated until an intensive metal oxidation begins at its
upper end; (2) Static combustion, during which a laminar liquid "cap" slowly
grows on the upper rod end; and, after the liquid cap detachment from the
sample, (3) Dynamic combustion, which is characterized by a rapid metal
consumption and turbulent liquid motions. An analytical description of these
stages is given. In particular, a model of the dynamic combustion is
constructed based on the turbulent oxygen transport through the liquid
metal-oxide flow. This model yields a simple expression for the fraction of
metal burned in the process, and allows one to calculate the normal propagation
speed of the solid metal--liquid interface as a function of the oxygen flow
speed and pressure. A comparison of the theory with the experimental results is
made.


title:
Adaptive regularization for Lasso models in the context of
  non-stationary data streams

abstract:
  Large scale, streaming datasets are ubiquitous in modern machine learning.
Streaming algorithms must be scalable, amenable to incremental training and
robust to the presence of non-stationarity. In this work consider the problem
of learning $\ell_1$ regularized linear models in the context of streaming
data. In particular, the focus of this work revolves around how to select the
regularization parameter when data arrives sequentially and the underlying
distribution is non-stationary (implying the choice of optimal regularization
parameter is itself time-varying). We propose a framework through which to
infer an adaptive regularization parameter. Our approach employs an $\ell_1$
penalty constraint where the corresponding sparsity parameter is iteratively
updated via stochastic gradient descent. This serves to reformulate the choice
of regularization parameter in a principled framework for online learning. The
proposed method is derived for linear regression and subsequently extended to
generalized linear models. We validate our approach using simulated and real
datasets and present an application to a neuroimaging dataset.


title:
Intensity and radiation statistics of correlated dipoles in GHZ and
  W-states

abstract:
  We investigate the super and sub-radiance characteristics of the radiation
emitted from a system of three two-level atoms, in the GHZ and W-states. The
dipolar coupling between atoms leads to two distinct configurations, one in
which the three atoms are on a line, and the other in a closed loop form,
wherein each atom interacts with both its neighbours. The quantum statistical
properties of the emitted radiation show distinctly different characteristics
for the GHZ and W-states resulting from the above configurations. The far-field
radiation pattern also shows distinct differences between differently entangled
states, making it possible for optical probing of entangled states.


title: The trace on projective representations of quantum groups

abstract:
  For certain roots of unity, we consider the categories of weight modules over
three quantum groups: small, un-restricted and unrolled. The first main theorem
of this paper is to show that there is a modified trace on the projective
modules of the first two categories. The second main theorem is to show that
category over the unrolled quantum group is ribbon. Partial results related to
these theorems were known previously.


title: Improved Lower Bounds for Graph Embedding Problems

abstract:
  In this paper, we give new, tight subexponential lower bounds for a number of
graph embedding problems. We introduce two related combinatorial problems,
which we call String Crafting and Orthogonal Vector crafting, and show that
these cannot be solved in time $2^{o(|s|/\log{|s|})}$, unless the Exponential
Time Hypothesis fails.
  These results are used to obtain simplified hardness results for several
graph embedding problems, on more restricted graph classes than previously
known: assuming the Exponential Time Hypothesis, there do not exist algorithms
that run in $2^{o(n/\log n)}$ time for Subgraph Isomorphism on graphs of
pathwidth 1, Induced Subgraph Isomorphism on graphs of pathwidth 1, Graph Minor
on graphs of pathwidth 1, Induced Graph Minor on graphs of pathwidth 1,
Intervalizing 5-Colored Graphs on trees, and finding a tree or path
decomposition with width at most $c$ with a minimum number of bags, for any
fixed $c\geq 16$.
  $2^{\Theta(n/\log n)}$ appears to be the "correct" running time for many
packing and embedding problems on restricted graph classes, and we think String
Crafting and Orthogonal Vector Crafting form a useful framework for
establishing lower bounds of this form.