title: Boson Representation of Spin Operators

abstract:
  The derivation of the boson representation of spin operators is given which
reproduces the Holstein-Primakoff and Dyson-Maleev transformations in the
corresponding cases. The suggested formalism allows to address some subtle
issues which appear crucial for treating certain class of problems. Moreover,
the transformation is suggested which is naturally related to the symmetry of
the spin systems.


title:
Of Hags and bitches. Ageist attitudes in 2016 presidential debate on
  twitter

abstract:
  In this article we present our exploratory research into the occurrence of
ageist attitudes within the discussion related to the US 2016 presidential
election. We use natural processing techniques to analyze the content tweets
related to Hillary Clinton and Donald Trump. Content analysis shows that
although ageist attitudes are scarce in the discussion, they are mostly focused
on Hillary Clinton rather than Donald Trump. Also, ageist arguments against
Donald Trump appear mostly as a reply to controversies connected with the
health of Hillary Clinton.


title: Fully differential NLO predictions for the rare muon decay

abstract:
  Using the automation program GoSam, fully differential NLO corrections were
obtained for the rare decay of the muon $\mu\to e\nu\bar\nu ee$. This process
is an important Standard Model background to searches of the Mu3e collaboration
for lepton-flavour violation, as it becomes indistinguishable from the signal
$\mu\to 3e$ if the neutrinos carry little energy. With our NLO program we are
able to compute the branching ratio as well as custom-tailored observables for
the experiment. With minor modifications, related decays of the tau can also be
computed.


title: Smartphone-based Vehicle Telematics - A Ten-Year Anniversary

abstract:
  Just like it has irrevocably reshaped social life, the fast growth of
smartphone ownership is now beginning to revolutionize the driving experience
and change how we think about automotive insurance, vehicle safety systems, and
traffic research. This paper summarizes the first ten years of research in
smartphone-based vehicle telematics, with a focus on user-friendly
implementations and the challenges that arise due to the mobility of the
smartphone. Notable academic and industrial projects are reviewed, and system
aspects related to sensors, energy consumption, cloud computing, vehicular ad
hoc networks, and human-machine interfaces are examined. Moreover, we highlight
the differences between traditional and smartphonebased automotive navigation,
and survey the state-of-the-art in smartphone-based transportation mode
classification, driver classification, and road condition monitoring. Future
advances are expected to be driven by improvements in sensor technology,
evidence of the societal benefits of current implementations, and the
establishment of industry standards for sensor fusion and driver assessment


title: Excursion set peaks: the role of shear

abstract:
  Recent analytical work on the modelling of dark halo abundances and
clustering has demonstrated the advantages of combining the excursion set
approach with peaks theory. We extend these ideas and introduce a model of
excursion set peaks that incorporates the role of initial tidal effects or
shear in determining the gravitational collapse of dark haloes. The model -- in
which the critical density threshold for collapse depends on the tidal
influences acting on protohaloes -- is well motivated from ellipsoidal collapse
arguments and is also simple enough to be analytically tractable. We show that
the predictions of this model are in very good agreement with measurements of
the halo mass function and traditional scale dependent halo bias in N-body
simulations across a wide range of masses and redshift. The presence of shear
in the collapse threshold means that halo bias is naturally predicted to be
nonlocal, and that protohalo densities at fixed mass are naturally predicted to
have Lognormal-like distributions. We present the first direct estimate of
Lagrangian nonlocal bias in N-body simulations, finding broad agreement with
the model prediction. Finally, the simplicity of the model (which has
essentially a single free parameter) opens the door to building efficient and
accurate non-universal fitting functions of halo abundances and bias for use in
precision cosmology.


title: Presence of magnetic excitations in SmFeAsO

abstract:
  We measured dispersive spin excitations in $\mathrm{SmFeAsO}$, parent
compound of $\mathrm{SmFeAsO_{\text{1-x}}F_{\text{x}}}$ one of the highest
temperature superconductors of Fe pnictides (T$_{\text{C}}\approx$55~K). We
determine the magnetic excitations to disperse with a bandwidth energy of ca
170 meV at (0.47, 0) and (0.34, 0.34), which merges into the elastic line
approaching the $\Gamma$ point. Comparing our results with other parent Fe
pnictides, we show the importance of structural parameters for the magnetic
excitation spectrum, with small modifications of the tetrahedron angles and As
height strongly affecting the magnetism.


title:
Intra-layer doping effects on the high-energy magnetic correlations in
  NaFeAs

abstract:
  We have used Resonant Inelastic X-ray Scattering (RIXS) and dynamical
susceptibility calculations to study the magnetic excitations in
NaFe$_{1-x}$Co$_x$As (x = 0, 0.03, and 0.08). Despite a relatively low ordered
magnetic moment, collective magnetic modes are observed in parent compounds (x
= 0) and persist in optimally (x = 0.03) and overdoped (x = 0.08) samples.
Their magnetic bandwidths are unaffected by doping within the range
investigated. High energy magnetic excitations in iron pnictides are robust
against doping, and present irrespectively of the ordered magnetic moment.
Nevertheless, Co doping slightly reduces the overall magnetic spectral weight,
differently from previous studies on hole-doped BaFe$_{2}$As$_{2}$, where it
was observed constant. Finally, we demonstrate that the doping evolution of
magnetic modes is different for the dopants being inside or outside the Fe-As
layer.


title: A timing view of the heartbeat state of GRS 1915+105

abstract:
  We present a timing analysis of two Rossi X-ray Timing Explorer observations
of the microquasar GRS 1915+105 during the heartbeat state. The
phase-frequency-power maps show that the intermediate-frequency aperiodic X-ray
variability weakens as the source softens in the slow rise phase, and when the
quasi-periodic oscillation disappears in the rise phase of the pulse of the
double-peaked class its sub-harmonic is still present with a hard phase lag. In
the slow rise phase, the energy-frequency-power maps show that most of the
aperiodic variability is produced in the corona, and may also induce the
aperiodic variability observed at low energies from an accretion disk, which is
further supported by the soft phase lag especially in the
intermediate-frequency range (with a time delay up to 20 ms). In the rise phase
of the pulse, the low-frequency aperiodic variability is enhanced significantly
and there is a prominent hard lag (with a time delay up to 50 ms), indicating
that the variability is induced by extension of the disk toward small radii as
implied by the increase in flux and propagates into the corona. However, during
the hard pulse of the double-peaked class, the variability shows no significant
lag, which may be attributed to an optically thick corona. These timing results
are generally consistent with the spectral results presented by Neilsen et al.
(2011, 2012) which indicated that the slow rise phase corresponds to a local
Eddington limit and the rise phase of the pulse corresponds to a radiation
pressure instability in the disk.


title: Controlled isotope arrangement in 13C enriched carbon nanotubes

abstract:
  We report the synthesis of a novel isotope engineered $^{13}{\rm
C}$--$^{12}{\rm C}$ heteronuclear nanostructure: single-wall carbon nanotubes
made of $^{13}{\rm C}$ enriched clusters which are embedded in natural carbon
regions. The material is synthesized with a high temperature annealing from
$^{13}{\rm C}$ enriched benzene and natural ${\rm C}_{60}$, which are
co-encapsulated inside host SWCNTs in an alternating fashion. The Raman 2D line
indicates that the $^{13}{\rm C}$ isotopes are not distributed uniformly in the
inner tubes. A semi-empirical method based modeling of the Raman modes under
$^{13}{\rm C}$ isotope enrichment shows that experimental data is compatible
with the presence of $^{13}{\rm C}$ rich clusters which are embedded in a
natural carbon containing matrix. This material may find applications in
quantum information processing and storage using nuclear spins as qubits.


title: Invertibility and Largest Eigenvalue of Symmetric Matrix Signings

abstract:
  The spectra of signed matrices have played a fundamental role in social
sciences, graph theory, and control theory. In this work, we investigate the
computational problems of identifying symmetric signings of matrices with
natural spectral properties. Our results are twofold:
  1. We show NP-completeness for the following three problems: verifying
whether a given matrix has a symmetric signing that is positive
semi-definite/singular/has bounded eigenvalues. However, we also illustrate
that the complexity could substantially differ for input matrices that are
adjacency matrices of graphs.
  2. We exhibit a stark contrast between invertibility and the above-mentioned
spectral properties: we show a combinatorial characterization of matrices with
invertible symmetric signings and design an efficient algorithm using this
characterization to verify whether a given matrix has an invertible symmetric
signing. Next, we give an efficient algorithm to solve the search problem of
finding an invertible symmetric signing for matrices whose support graph is
bipartite. We also provide a lower bound on the number of invertible symmetric
signed adjacency matrices. Finally, we give an efficient algorithm to find a
minimum increase in support of a given symmetric matrix so that it has an
invertible symmetric signing.
  We use combinatorial and spectral techniques in addition to classic results
from matching theory. Our combinatorial characterization of matrices with
invertible symmetric signings might be of independent interest.


title: Remarks on the Rellich inequality

abstract:
  We study the Rellich inequalities in the framework of equalities. We present
equalities which imply the Rellich inequalities by dropping remainders. This
provides a simple and direct understanding of the Rellich inequalities as well
as the nonexistence of nontrivial extremisers.


title: Secondary Cosmic Ray Nuclei in the Light of the Single Source Model

abstract:
  Evidence for a local 'Single Source' of cosmic rays is amassing by way of the
recent precise measurements of various cosmic ray energy spectra from the
AMS-02 instrument. To observations of individual cosmic ray nuclei, electrons,
positrons and antiprotons must now be added the determination of the
boron-to-carbon ratio and the energy spectrum of lithium to 2000 GV with high
precision. Our analysis leads us to claim that, with certain assumptions about
propagation in the Galaxy, the results confirm our arguments regarding the
presence of a local single source, perhaps, a supernova remnant (SNR). An
attempt is made to determine some of the properties of this SNR and its
progenitor star.


title: Fiber and Crystals Dual Readout calorimeters

abstract:
  The RD52 (DREAM) collaboration is performing R\&D on dual readout calorimetry
techniques with the aim of improving hadronic energy resolution for future high
energy physics experiments. The simultaneous detection of Cherenkov and
scintillation light enables us to measure the electromagnetic fraction of
hadron shower event-by-event. As a result, we could eliminate the main
fluctuation which prevented from achieving precision energy measurement for
hadrons.
  We have tested the performance of the lead and copper fiber prototypes
calorimeters with various energies of electromagnetic particles and hadrons.
During the beam test, we investigated the energy resolutions for electrons and
pions as well as the identification of those particles in a longitudinally
unsegmented calorimeter.
  Measurements were also performed on pure and doped PbWO$_{4}$ crystals, as
well as BGO and BSO, with the aim of realising a crystal based dual readout
detector. We will describe our results, focusing on the more promising
properties of homogeneous media for the technique. Guidelines for additional
developments on crystals will be also given.
  Finally we discuss the construction techniques that we have used to assemble
our prototypes and give an overview of the ones that could be industrialized
for the construction of a full hermetic calorimeter.


title: On Proving Confluence Modulo Equivalence for Constraint Handling Rules

abstract:
  Previous results on proving confluence for Constraint Handling Rules are
extended in two ways in order to allow a larger and more realistic class of CHR
programs to be considered confluent. Firstly, we introduce the relaxed notion
of confluence modulo equivalence into the context of CHR: while confluence for
a terminating program means that all alternative derivations for a query lead
to the exact same final state, confluence modulo equivalence only requires the
final states to be equivalent with respect to an equivalence relation tailored
for the given program. Secondly, we allow non-logical built-in predicates such
as var/1 and incomplete ones such as is/2, that are ignored in previous work on
confluence.
  To this end, a new operational semantics for CHR is developed which includes
such predicates. In addition, this semantics differs from earlier approaches by
its simplicity without loss of generality, and it may also be recommended for
future studies of CHR.
  For the purely logical subset of CHR, proofs can be expressed in first-order
logic, that we show is not sufficient in the present case. We have introduced a
formal meta-language that allows reasoning about abstract states and
derivations with meta-level restrictions that reflect the non-logical and
incomplete predicates. This language represents subproofs as diagrams, which
facilitates a systematic enumeration of proof cases, pointing forward to a
mechanical support for such proofs.


title:
Pre-flare coronal jet and evolutionary phases of a solar eruptive
  prominence associated with M1.8 flare: SDO and RHESSI observations

abstract:
  We investigate triggering, activation, and ejection of a solar eruptive
prominence that occurred in a multi-polar flux system of active region NOAA
11548 on 2012 August 18 by analyzing data from AIA on board SDO, RHESSI, and
EUVI/SECCHI on board STEREO. Prior to the prominence activation, we observed
striking coronal activities in the form of a blowout jet which is associated
with rapid eruption of a cool flux rope. Further, the jet-associated flux rope
eruption underwent splitting and rotation during its outward expansion. These
coronal activities are followed by the prominence activation during which it
slowly rises with a speed of ~12 km/s while the region below the prominence
emits gradually varying EUV and thermal X-ray emissions. From these
observations, we propose that the prominence eruption is a complex, multi-step
phenomenon in which a combination of internal (tether-cutting reconnection) and
external (i.e., pre-eruption coronal activities) processes are involved. The
prominence underwent catastrophic loss of equilibrium with the onset of the
impulsive phase of an M1.8 flare suggesting large-scale energy release by
coronal magnetic reconnection. We obtained signatures of particle acceleration
in the form of power law spectra with hard electron spectral index (delta ~ 3)
and strong HXR footpoint sources. During the impulsive phase, a hot EUV
plasmoid was observed below the apex of the erupting prominence that ejected in
the direction of the prominence with a speed of ~177 km/s. The temporal,
spatial and kinematic correlations between the erupting prominence and the
plasmoid imply that the magnetic reconnection supported the fast ejection of
prominence in the lower corona.


title: A Category of Probability Spaces

abstract:
  We introduce a category Prob of probability spaces whose objects are all
probability spaces and arrows are corresponding to measurable functions
satisfying an absolutely continuous requirement. We can consider a Prob-arrow
as an evolving direction of information with a way of its interpretation. We
introduce a contravariant functor E from Prob to Set, the category of sets. The
functor E provides conditional expectations along arrows in Prob, which are
generalizations of the classical conditional expectations. For a Prob arrow f,
we introduce two concepts f-measurability and f-independence and investigate
their interaction with conditional expectations along f. We also show that the
completion of probability spaces is naturally formulated as an endofunctor of
Prob.


title:
Voxblox: Incremental 3D Euclidean Signed Distance Fields for On-Board
  MAV Planning

abstract:
  Micro Aerial Vehicles (MAVs) that operate in unstructured, unexplored
environments require fast and flexible local planning, which can replan when
new parts of the map are explored. Trajectory optimization methods fulfill
these needs, but require obstacle distance information, which can be given by
Euclidean Signed Distance Fields (ESDFs).
  We propose a method to incrementally build ESDFs from Truncated Signed
Distance Fields (TSDFs), a common implicit surface representation used in
computer graphics and vision. TSDFs are fast to build and smooth out sensor
noise over many observations, and are designed to produce surface meshes.
Meshes allow human operators to get a better assessment of the robot's
environment, and set high-level mission goals.
  We show that we can build TSDFs faster than Octomaps, and that it is more
accurate to build ESDFs out of TSDFs than occupancy maps. Our complete system,
called voxblox, will be available as open source and runs in real-time on a
single CPU core. We validate our approach on-board an MAV, by using our system
with a trajectory optimization local planner, entirely on-board and in
real-time.


title:
Shape model of asteroid (130) Elektra from optical photometry and
  disk-resolved images from VLT/SPHERE and Nirc2/Keck

abstract:
  Asteroid (130) Elektra belongs to one of the six known triple asteroids in
the main belt, so its mass has been reliably determined. We aim to use all
available disk-resolved images of (130) Elektra obtained by the SPHERE
instrument at VLT and by the Nirc2 of the Keck telescope together with the
disk-integrated photometry to determine its shape model and its size. The
volume can be then used in combination with the known mass to derive the bulk
density of the primary. We apply the All-Data Asteroid Modeling (ADAM)
algorithm to the optical disk-integrated data, 2 disk-resolved images obtained
by the SPHERE instrument and 13 disk-resolved images from the Nirc2 of the Keck
telescope, and derive the shape model and size of Elektra. We present the shape
model, volume-equivalent diameter (199$\pm$7 km) and bulk density
(1.60$\pm$0.13 g cm$^{-3}$) of the C-type asteroid Elektra.


title: A New Proof to the Period Problems of GL(2)

abstract:
  We use the relations between the base change representations, theta lifts and
Whittaker model, to give a new proof to the period problems of $GL(2)$ over a
quadratic local field extension $E/F.$ And we classify both local and global
$D^\times(F)-$distinguished representations $\pi^D$ of $D^\times(E),$ where
$D^\times$ is an inner form of $GL_2$ defined over a nonarchimedean field or a
number field $F.$


title:
Left-invariant Sub-Riemannian Engel structures: abnormal geodesics and
  integrability

abstract:
  We provide the first known family of examples of integrable homogeneous
sub-Riemannian structures admitting strictly abnormal geodesics. These examples
were obtained through the analysis of the equivalence problem for
sub-Riemannian Engel structures. We formulate a criterion of strict abnormality
in terms of structure functions of a canonical frame on a sub-Riemannian Engel
manifold as well as estimates on conjugate times.


title: What antineutrinos can tell about octant and $\delta_{CP}$ in DUNE?

abstract:
  We study the efficiency of DUNE, a next generation long baseline oscillation
experiment to resolve two major unknowns in neutrino oscillation physics. These
are, octant of $\theta_{23}$ (i.e. if $\theta_{23}$ is $< 45^\circ$ or
$>45^\circ$) and Dirac CP phase $\delta_{CP}$. We mainly focus on the role of
antineutrinos when they travel 1300 km baseline of DUNE. We observe that for
DUNE, the antineutrino runs help to remove parameter degeneracies even in the
parameter space where the antineutrino probability suffers from various
degeneracies. We study these points in detail and find that, due to enhanced
matter effect longer baseline experiments create an increased tension between
the neutrino and the antineutrino probabilities which helps to increase total
sensitivity in case of combined runs. We also find that, antineutrino run
increases overall CP sensitivity due to its ability to abolish
octant-$\delta_{CP}$ degeneracy.


title:
Polynomial mixing of the edge-flip Markov chain for unbiased dyadic
  tilings

abstract:
  We give the first polynomial upper bound on the mixing time of the edge-flip
Markov chain for unbiased dyadic tilings, resolving an open problem originally
posed by Janson, Randall, and Spencer in 2002. A dyadic tiling of size n is a
tiling of the unit square by n non-overlapping dyadic rectangles, each of area
1/n, where a dyadic rectangle is any rectangle that can be written in the form
[a2^{-s}, (a+1)2^{-s}] \times [b2^{-t}, (b+1)2^{-t}] for non-negative integers
a,b,s,t. The edge-flip Markov chain selects a random edge of the tiling and
replaces it with its perpendicular bisector if doing so yields a valid dyadic
tiling. Specifically, we show that the relaxation time of the edge-flip Markov
chain for dyadic tilings is at most O(n^{4.09}), which implies that the mixing
time is at most O(n^{5.09}). We complement this by showing that the relaxation
time is at least \Omega(n^{1.38}), improving upon the previously best lower
bound of \Omega(n\log n) coming from the diameter of the chain.


title: The impact of anticipation in dynamical systems

abstract:
  Collective motion in biology is often modelled as a dynamical system, in
which individuals are represented as particles whose interactions are
determined by the current state of the system. Many animals, however, including
humans, have predictive capabilities, and presumably base their behavioural
decisions---at least partially---upon an anticipated state of their
environment. We explore a minimal version of this idea in the context of
particles that interact according to a pairwise potential. Anticipation enters
the picture by calculating the interparticle forces from linear extrapolations
of the particle positions some time $\tau$ into the future. Simulations show
that for intermediate values of $\tau$, compared to a transient time scale
defined by the potential and the initial conditions, the particles form
rotating clusters in which the particles are arranged in a hexagonal pattern.
Analysis of the system shows that anticipation induces energy dissipation and
we show that the kinetic energy asymptotically decays as $1/t$. Furthermore, we
show that the angular momentum is not necessarily conserved for $\tau >0$, and
that asymmetries in the initial condition therefore can cause rotational
movement. These results suggest that anticipation could play an important role
in collective behaviour, since it induces pattern formation and stabilises the
dynamics of the system.


title:
Isotope effect on the transition temperature $T_c$ in Fe-based
  superconductors: the current status

abstract:
  The results of the Fe isotope effect (Fe-IE) on the transition temperature
$T_c$ obtained up to date in various Fe-based high temperature superconductors
are summarized and reanalyzed by following the approach developed in [Phys.
Rev. B 82, 212505 (2010)]. It is demonstrated that the very controversial
results for Fe-IE on $T_c$ are caused by small structural changes occurring
simultaneously with the Fe isotope exchange. The Fe-IE exponent on $T_c$
[$\alpha_{\rm Fe}=-(\Delta T_c/T_c)/(\Delta M/M)$, $M$ is the isotope mass]
needs to be decomposed into two components with the one related to the
structural changes ($\alpha_{\rm Fe}^{\rm str}$) and the genuine (intrinsic)
one ($\alpha_{\rm Fe}^{\rm int}$). The validity of such decomposition is
further confirmed by the fact that $\alpha_{\rm Fe}^{\rm int}$ coincides with
the Fe-IE exponent on the characteristic phonon frequencies $\alpha_{\rm
Fe}^{\rm ph}$ as is reported in recent EXAFS and Raman experiments.


title: When is a scale-free graph ultra-small?

abstract:
  In this paper we study typical distances in the configuration model, when the
degrees have asymptotically infinite variance. We assume that the empirical
degree distribution follows a power law with exponent $\tau\in (2,3)$, up to
value $n^{\beta_n}$ for some $\beta_n\gg (\log n)^{-\gamma}$ and
$\gamma\in(0,1)$. This assumption is satisfied for power law i.i.d. degrees,
and also includes truncated power-law distributions where the (possibly
exponential) truncation happens at $n^{\beta_n}$. We show that the graph
distance between two uniformly chosen vertices centers around $2 \log \log
(n^{\beta_n}) / |\log (\tau-2)| + 1/(\beta_n(3-\tau))$, with tight
fluctuations. Thus, the graph is an \emph{ultrasmall world} whenever
$1/\beta_n=o(\log\log n)$. We determine the distribution of the fluctuations
around this value, in particular we prove that these are non-converging tight
random variables that show $\log \log$-periodicity. We describe the topology
and number of shortest paths: We show that the number of shortest paths is of
order $n^{f_n\beta_n}$, where $f_n \in (0,1)$ is a random variable that
oscillates with $n$. The two end-segments of any shortest path have length
$\log \log (n^{\beta_n}) / |\log (\tau-2)|$+tight, and the total degree is
increasing towards the middle of the path on these segments. The connecting
middle segment has length $1/(\beta_n(3-\tau))$+tight, and it contains only
vertices with degree at least of order $n^{(1-f_n)\beta_n}$, thus all the
degrees on this segment are comparable to the maximal degree. Our theorems also
apply when instead of truncating the degrees, we start with a configuration
model and we remove every vertex with degree at least $n^{\beta_n}$, and the
edges attached to these vertices. This sheds light on the attack vulnerability
of the configuration model with infinite variance degrees.


title: A molecular fountain

abstract:
  The resolution of any spectroscopic or interferometric experiment is
ultimately limited by the total time a particle is interrogated. We here
demonstrate the first molecular fountain, a development which permits hitherto
unattainably long interrogation times with molecules. In our experiments,
ammonia molecules are decelerated and cooled using electric fields, launched
upwards with a velocity between 1.4 and 1.9\,m/s and observed as they fall back
under gravity. A combination of quadrupole lenses and bunching elements is used
to shape the beam such that it has a large position spread and a small velocity
spread (corresponding to a transverse temperature of $<$10\,$\mu$K and a
longitudinal temperature of $<$1\,$\mu$K) when the molecules are in free fall,
while being strongly focused at the detection region. The molecules are in free
fall for up to 266\,milliseconds, making it possible to perform sub-Hz
measurements in molecular systems and paving the way for stringent tests of
fundamental physics theories.


title:
Improving Reliability of Word Similarity Evaluation by Redesigning
  Annotation Task and Performance Measure

abstract:
  We suggest a new method for creating and using gold-standard datasets for
word similarity evaluation. Our goal is to improve the reliability of the
evaluation, and we do this by redesigning the annotation task to achieve higher
inter-rater agreement, and by defining a performance measure which takes the
reliability of each annotation decision in the dataset into account.


title: Gluon and Ghost Dynamics from Lattice QCD

abstract:
  The two point gluon and ghost correlation functions and the three gluon
vertex are investigated, in the Landau gauge, using lattice simulations. For
the two point functions, we discuss the approach to the continuum limit looking
at the dependence on the lattice spacing and volume. The analytical structure
of the propagators is also investigated by computing the corresponding spectral
functions using an implementation of the Tikhonov regularisation to solve the
integral equation. For the three point function we report results when the
momentum of one of the gluon lines is set to zero and discuss its implications.


title:
Glimpses of black hole formation/evaporation in highly inelastic,
  ultra-planckian string collisions

abstract:
  We revisit possible glimpses of black-hole formation by looking at
ultra-planckian string-string collisions at very high final-state multiplicity.
We compare, in particular, previous results using the optical theorem, the
resummation of ladder diagrams at arbitrary loop order, and the AGK cutting
rules, with the more recent study of $2 \rightarrow N$ scattering at $N \sim s
M_P^{-2} \gg 1$. We argue that some apparent tension between the two approaches
disappears once a reinterpretation of the latter's results in terms of suitably
defined infrared-safe cross sections is adopted. Under that assumption, the
typical final state produced in an ultra-planckian collision does indeed appear
to share some properties with those expected from the evaporation of a black
hole of mass $\sqrt{s}$, although no sign of thermalization is seen to emerge
at this level of approximation.


title: The spectrum for commutative complex $K$-theory

abstract:
  We study commutative complex $K$-theory, a generalised cohomology theory
built from spaces of ordered commuting tuples in the unitary groups. We show
that the spectrum for commutative complex $K$-theory is stably equivalent to
the $ku$-group ring of $BU(1)$ and thus obtain a splitting of its representing
space $B_{com}U$ as a product of all the terms in the Whitehead tower for $BU$,
$B_{com}U\simeq BU\times BU\langle 4\rangle \times BU\langle 6\rangle \times
\dots .$ As a consequence of the spectrum level identification we obtain the
ring of coefficients for this theory. Using the rational Hopf ring for
$B_{com}U$ we describe the relationship of our results with a previous
computation of the rational cohomology algebra of $B_{com}U$. This gives an
essentially complete description of the space $B_{com}U$ introduced by A. Adem
and J. G\'omez.


title: Latching dynamics in neural networks with synaptic depression

abstract:
  Priming is the ability of the brain to more quickly activate a target concept
in response to a related stimulus (prime). Experiments point to the existence
of an overlap between the populations of the neurons coding for different
stimuli. Other experiments show that prime-target relations arise in the
process of long term memory formation. The classical modelling paradigm is that
long term memories correspond to stable steady states of a Hopfield network
with Hebbian connectivity. Experiments show that short term synaptic depression
plays an important role in the processing of memories. This leads naturally to
a computational model of priming, called latching dynamics; a stable state
(prime) can become unstable and the system may converge to another transiently
stable steady state (target). Hopfield network models of latching dynamics have
been studied by means of numerical simulation, however the conditions for the
existence of this dynamics have not been elucidated. In this work we use a
combination of analytic and numerical approaches to confirm that latching
dynamics can exist in the context of Hebbian learning, however lacks robustness
and imposes a number of biologically unrealistic restrictions on the model. In
particular our work shows that the symmetry of the Hebbian rule is not an
obstruction to the existence of latching dynamics, however fine tuning of the
parameters of the model is needed.


title:
Has global warming modified the relationship between sunspot numbers and
  global temperatures?

abstract:
  We study time evolution of the relationship between sunspot numbers and
global temperatures between 1880 and 2016 using wavelet coherence framework.
The results suggest that the relationship is stable in time. Changes in the
sunspot numbers precede changes in the temperatures by more than two years as
suggested by the wavelet phase differences. This leading position of the sun
activity is stable in time as well. However, the relationship has been
disturbed by increasing $CO_2$ emissions since 1960s. Without controlling for
the effect of possible global warming, or more precisely the positive
connection between increasing $CO_2$ emissions and the global temperatures, the
findings would have been quite different. Combination of the cointegration
analysis and wavelet coherence framework has enabled uncovering a hidden
relationship between the solar activity and global temperatures, and possibly
explaining equivocal results in the topical literature.


title:
On corners scattering stably and stable shape determination by a single
  far-field pattern

abstract:
  In this paper, we establish two sharp quantitative results for the direct and
inverse time-harmonic acoustic wave scattering. The first one is concerned with
the recovery of the support of an inhomogeneous medium, independent of its
contents, by a single far-field measurement. For this challenging inverse
scattering problem, we establish a sharp stability estimate of logarithmic type
when the medium support is a polyhedral domain in $\mathbb{R}^n$, $n=2,3$. The
second one is concerned with the stability for corner scattering. More
precisely if an inhomogeneous scatterer, whose support has a corner, is probed
by an incident plane-wave, we show that the energy of the scattered far-field
possesses a positive lower bound depending only on the geometry of the corner
and bounds on the refractive index of the medium there. This implies the
impossibility of approximate invisibility cloaking by a device containing a
corner and made of isotropic material. Our results sharply quantify the
qualitative corner scattering results in the literature, and the corresponding
proofs involve much more subtle analysis and technical arguments. As a
significant byproduct of this study, we establish a quantitative Rellich's
theorem that continues smallness of the wave field from the far-field up to the
interior of the inhomogeneity. The result is of significant mathematical
interest for its own sake and is surprisingly not yet known in the literature.


title: Large rainbow matchings in general graphs

abstract:
  By a theorem of Drisko, any $2n-1$ matchings of size $n$ in a bipartite graph
have a partial rainbow matching of size $n$. Inspired by discussion of Bar\'at,
Gy\'arf\'as and S\'ark\"ozy, we conjecture that if $n$ is odd then the same is
true also in general graphs, and that if $n$ is even then $2n$ matchings of
size $n$ suffice. We prove that any $3n-2$ matchings of size $n$ have a partial
rainbow matching of size $n$.


title:
Interplay of soft and perturbative correlations in multiparton
  interactions at central rapidities

abstract:
  We study the role of soft/nonperturbative correlations in the multi parton
interactions in the central kinematics relevant for double parton scattering
(DPS) and underlying event (UE) measurements at ATLAS and CMS. We show that the
effect of soft correlations is negligible for DPS regime (typical transverse
momenta larger than 10-20 GeV), but may be important for UE (several GeV
scale). The characteristic scale where soft correlations become important
increases with decrease of $x$ (energy increase) leading to approximately
constant \effs at small x.


title: Lee-Wick Black Holes

abstract:
  We derive and study an approximate static vacuum solution generated by a
point-like source in a higher derivative gravitational theory with a pair of
complex conjugate ghosts. The gravitational theory is local and characterized
by a high derivative operator compatible with Lee-Wick unitarity. In
particular, the tree-level two-point function only shows a pair of complex
conjugate poles besides the massless spin two graviton. We show that
singularity-free black holes exist when the mass of the source $M$ exceeds a
critical value $M_{\rm crit}$. For $M > M_{\rm crit}$ the spacetime structure
is characterized by an outer event horizon and an inner Cauchy horizon, while
for $M = M_{\rm crit}$ we have an extremal black hole with vanishing Hawking
temperature. The evaporation process leads to a remnant that approaches the
zero-temperature extremal black hole state in an infinite amount of time.


title: Torsion as a Dark Matter Candidate from the Higgs Portal

abstract:
  Torsion is a metric-independent component of gravitation, which may provide a
more general geometry than the one taking place within general relativity. On
the other hand torsion could lead to interesting phenomenology in both particle
physics and cosmology. In the present work it is shown that a torsion field
interacting with the SM Higgs doublet and having a negligible coupling to SM
fermions is protected from decaying by a $Z_2$ symmetry, and therefore becomes
a promising Dark Matter (DM) candidate. In order to check the consistency of
this scenario we evaluate the DM relic density and explore direct DM detection
and collider constraints on this model. It turns out that in the model when the
Higgs boson is only partly responsible for the generation of torsion mass,
there is a region of parameter space where torsion contributes 100% to the DM
budget of the Universe. Furthermore, we show that the LHC currently has a
limited sensitivity to the torsion parameter space via mono-jet signature and
will be able to considerably improve its coverage of the torsion parameter
space with the projected high luminosity.


title:
Show me the material evidence: Initial experiments on evaluating
  hypotheses from user-generated multimedia data

abstract:
  Subjective questions such as `does neymar dive', or `is clinton lying', or
`is trump a fascist', are popular queries to web search engines, as can be seen
by autocompletion suggestions on Google, Yahoo and Bing. In the era of
cognitive computing, beyond search, they could be handled as hypotheses issued
for evaluation. Our vision is to leverage on unstructured data and metadata of
the rich user-generated multimedia that is often shared as material evidence in
favor or against hypotheses in social media platforms. In this paper we present
two preliminary experiments along those lines and discuss challenges for a
cognitive computing system that collects material evidence from user-generated
multimedia towards aggregating it into some form of collective decision on the
hypothesis.


title: Chiral Thermodynamics in a finite box

abstract:
  Finite-volume modifications of the two-flavor chiral phase diagram are
investigated within an effective quark-meson model in various mean-field
approximations. The role of vacuum fluctuations and boundary conditions, their
influence on higher cumulants and signatures of a possible pseudo-critical
endpoint are amplified with smaller volumes.


title: On regular rotating black holes

abstract:
  Different proposals for regular rotating black hole spacetimes have appeared
recently in the literature. However, a rigorous analysis and proof of the
regularity of this kind of spacetimes is still lacking. In this note we analyze
rotating Kerr-like black hole spacetimes and find the necessary and sufficient
conditions for the regularity of all their second order scalar invariants
polynomial in the Riemann tensor. We also show that the regularity is linked to
a violation of the weak energy conditions around the core of the rotating black
hole.


title:
Improving Belief Propagation Decoding of Polar Codes Using Scattered
  EXIT Charts

abstract:
  For finite length polar codes, channel polarization leaves a significant
number of channels not fully polarized. Adding a Cyclic Redundancy Check (CRC)
to better protect information on the semi-polarized channels has already been
successfully applied in the literature, and is straightforward to be used in
combination with Successive Cancellation List (SCL) decoding. Belief
Propagation (BP) decoding, however, offers more potential for exploiting
parallelism in hardware implementation, and thus, we focus our attention on
improving the BP decoder. Specifically, similar to the CRC strategy in the
SCL-case, we use a short-length "auxiliary" LDPC code together with the polar
code to provide a significant improvement in terms of BER. We present the novel
concept of "scattered" EXIT charts to design such auxiliary LDPC codes, and
achieve net coding gains (Le. for the same total rate) of 0.4 dB at BER of 1E-5
compared to the conventional BP decoder.


title:
Compatibility Properties of Synchronously and Asynchronously
  Communicating Components

abstract:
  We study interacting components and their compatibility with respect to
synchronous and asynchronous composition. The behavior of components is
formalized by I/O-transition systems. Synchronous composition is based on
simultaneous execution of shared output and input actions of two components
while asynchronous composition uses unbounded FIFO-buffers for message
transfer. In both contexts we study compatibility notions based on the idea
that any output issued by one component should be accepted as an input by the
other. We distinguish between strong and weak versions of compatibility, the
latter allowing the execution of internal actions before a message is accepted.
We consider open systems and study conditions under which (strong/weak)
synchronous compatibility is sufficient and necessary to get (strong/weak)
asynchronous compatibility. We show that these conditions characterize
half-duplex systems. Then we focus on the verification of weak asynchronous
compatibility for possibly non half-duplex systems and provide a decidable
criterion that ensures weak asynchronous compatibility. We investigate
conditions under which this criterion is complete, i.e. if it is not satisfied
then the asynchronous system is not weakly asynchronously compatible. Finally,
we discuss deadlock-freeness and investigate relationships between
deadlock-freeness in the synchronous and in the asynchronous case.


title:
The Superluminous (Type I) Supernova ASASSN-15lh : A case for a
  Quark-Nova inside an Oxygen-type Wolf-Rayet supernova remnant

abstract:
  We show that a Quark-Nova (QN; the explosive transition of a neutron star to
a quark star) occurring a few days following the supernova explosion of an
Oxygen-type Wolf-Rayet (WO) star can account for the intriguing features of
ASASSN-15lh, including its extreme energetics, its double-peaked light-curve
and the evolution of its photospheric radius and temperature. A two-component
configuration of the homologously expanding WO remnant (an extended envelope
and a compact core) is used to harness the kinetic energy (>10^52 ergs) of the
QN ejecta. The delay between the WO SN and the QN yields a large (~ 10^4 Rsun)
envelope which when energized by the QN ejecta/shock gives the first peak in
our model. As the envelope's photosphere recedes into the slowly expanding, hot
and insulated, denser core (initially heated by the QN shock) a second hump
emerges. The spectrum in our model should reflect the composition of an WO SN
remnant re-heated by a QN going off in its wake.


title: A Massive Millisecond Pulsar in an Eccentric Binary

abstract:
  The recent discovery of a population of eccentric (e ~ 0.1) millisecond
pulsar (MSP) binaries with low-mass white dwarf companions in the Galactic
field represents a challenge to evolutionary models that explain MSP formation
as recycling: all such models predict that the orbits become highly
circularised during a long period of accretion. The members of this new
population exhibit remarkably similar properties (orbital periods,
eccentricities, companion masses, spin periods) and several models have been
put forward that suggest a common formation channel. In this work we present
the results of an extensive timing campaign focusing on one member of this new
population, PSR J1946+3417. Through measurement of the both the advance of
periastron and Shapiro delay for this system, we determine the mass of the
pulsar, companion and the inclination of the orbit to be 1.828(22) Msun,
0.2656(19) Msun and 76.4(6) , under the assumption that general relativity is
the true description of gravity. Notably, this is the third highest mass
measured for any pulsar. Using these masses and the astrometric properties of
PSR J1946+3417 we examine three proposed formation channels for eccentric MSP
binaries. While our results are consistent with eccentricity growth driven by a
circumbinary disk or neutron star to strange star phase transition, we rule out
rotationally delayed accretion-induced collapse as the mechanism responsible
for the configuration of the PSR J1946+3417 system.


title:
Spectroscopic observations of active solar-analog stars having high
  X-ray luminosity, as a proxy of superflare stars

abstract:
  Recent studies of solar-type superflare stars have suggested that even old
slowly rotating stars similar to the Sun can have large starspots and
superflares. We conducted high dispersion spectroscopy of 49 nearby
solar-analog stars (G-type main sequence stars with
$T_{\rm{eff}}\approx5,600\sim6,000$ K) identified as ROSAT soft X-ray sources,
which are not binary stars from the previous studies. We expected that these
stars can be used as a proxy of bright solar-analog superflare stars, since
superflare stars are expected to show strong X-ray luminosity. More than half
(37) of the 49 target stars show no evidence of binarity, and their atmospheric
parameters ($T_{\rm{eff}}$, $\log g$, and [Fe/H]) are within the range of
ordinary solar-analog stars. We measured Ca II 8542 and H$\alpha$ lines, which
are good indicators of the chromospheric activity. The intensity of these lines
indicates that all the target stars have large starspots. We also measured
$v\sin i$ (projected rotational velocity) and Lithium abundance for the target
stars. Li abundance is a key to understanding the evolution of the stellar
convection zone, which reflects the stellar age, mass and rotational history.
We confirmed that many of the target stars rapidly rotate and have high Li
abundance, compared with the Sun, as suggested by many previous studies. There
are, however, also some target stars that rotate slowly ($v\sin i$=2$\sim$3 km
s$^{-1}$) and have low Li abundance like the Sun. These results support that
old and slowly rotating stars similar to the Sun could have high activity level
and large starspots. This is consistent with the results of our previous
studies of solar-type superflare stars. In the future, it is important to
conduct long-term monitoring observations of these active solar-analog stars in
order to investigate detailed properties of large starspots from the viewpoint
of stellar dynamo theory.


title: Using text mining and machine learning for detection of child abuse

abstract:
  Abuse in any form is a grave threat to a child's health. Public health
institutions in the Netherlands try to identify and prevent different kinds of
abuse, and building a decision support system can help such institutions
achieve this goal. Such decision support relies on the analysis of relevant
child health data. A significant part of the medical data that the institutions
have on children is unstructured, and in the form of free text notes. In this
research, we employ machine learning and text mining techniques to detect
patterns of possible child abuse in the data. The resulting model achieves a
high score in classifying cases of possible abuse. We then describe our
implementation of the decision support API at a municipality in the
Netherlands.


title:
Mean field approaches for $\Xi^-$ hypernuclei and current experimental
  data

abstract:
  Motivated by the recently observed hypernucleus (Kiso event) $^{15}_{\Xi}$C
($^{14}$N$+\Xi^-$), we identify the state of this system theoretically within
the framework of the relativistic-mean-field and Skyrme-Hartree-Fock models.
The $\Xi N$ interactions are constructed to reproduce the two possibly observed
$\Xi^-$ removal energies, $4.38\pm 0.25$ MeV or $1.11\pm 0.25$ MeV. The present
result is preferable to be $^{14}{\rm N}({\rm g.s.})+\Xi^-(1p)$, corresponding
to the latter value.


title: Moduli spaces of (bi)algebra structures in topology and geometry

abstract:
  After introducing some motivations for this survey, we describe a formalism
to parametrize a wide class of algebraic structures occurring naturally in
various problems of topology, geometry and mathematical physics. This allows us
to define an "up to homotopy version" of algebraic structures which is coherent
(in the sense of $\infty$-category theory) at a high level of generality. To
understand the classification and deformation theory of these structures on a
given object, a relevant idea inspired by geometry is to gather them in a
moduli space with nice homotopical and geometric properties. Derived geometry
provides the appropriate framework to describe moduli spaces classifying
objects up to weak equivalences and encoding in a geometrically meaningful way
their deformation and obstruction theory. As an instance of the power of such
methods, I will describe several results of a joint work with Gregory Ginot
related to longstanding conjectures in deformation theory of bialgebras,
$E_n$-algebras and quantum group theory.


title:
On Symmetry of Birkhoff-James Orthogonality of Linear Operators on
  Finite-dimensional Real Banach Spaces

abstract:
  We characterize left symmetric linear operators on a finite dimensional
strictly convex and smooth real normed linear space $ \mathbb{X},$ which
answers a question raised recently by one of the authors in \cite{S} [D. Sain,
\textit{Birkhoff-James orthogonality of linear operators on finite dimensional
Banach spaces, Journal of Mathematical Analysis and Applications, accepted, $
2016 $}]. We prove that $ T\in B(\mathbb{X}) $ is left symmetric if and only if
$ T $ is the zero operator. If $ \mathbb{X} $ is two-dimensional then the same
characterization can be obtained without the smoothness assumption. We also
explore the properties of right symmetric linear operators defined on a finite
dimensional real Banach space. In particular, we prove that smooth linear
operators on a finite-dimensional strictly convex and smooth real Banach space
can not be right symmetric.


title: Stylized facts in social networks: Community-based static modeling

abstract:
  The past analyses of datasets of social networks have enabled us to make
empirical findings of a number of aspects of human society, which are commonly
featured as stylized facts of social networks, such as broad distributions of
network quantities, existence of communities, assortative mixing, and
intensity-topology correlations. Since the understanding of the structure of
these complex social networks is far from complete, for deeper insight into
human society more comprehensive datasets and modeling of the stylized facts
are needed. Although the existing dynamical and static models can generate some
stylized facts, here we take an alternative approach by devising a
community-based static model with heterogeneous community sizes and larger
communities having smaller link density and weight. With these few assumptions
we are able to generate realistic social networks that show most stylized facts
for a wide range of parameters, as demonstrated numerically and analytically.
Since our community-based static model is simple to implement and easily
scalable, it can be used as a reference system, benchmark, or testbed for
further applications.


title:
Functional Inference on Rotational Curves and Identification of Human
  Gait at the Knee Joint

abstract:
  We extend Gaussian perturbation models in classical functional data analysis
to the three-dimensional rotational group where a zero-mean Gaussian process in
the Lie algebra under the Lie exponential spreads multiplicatively around a
central curve. As an estimator, we introduce point-wise extrinsic mean curves
which feature strong perturbation consistency, and which are asymptotically
a.s. unique and differentiable, if the model is so. Further, we consider the
group action of time warping and that of spatial isometries that are connected
to the identity. The latter can be asymptotically consistently estimated if
lifted to the unit quaternions. Introducing a generic loss for Lie groups, the
former can be estimated, and based on curve length, due to asymptotic
differentiability, we propose two-sample permutation tests involving various
combinations of the group actions. This methodology allows inference on gait
patterns due to the rotational motion of the lower leg with respect to the
upper leg. This was previously not possible because, among others, the usual
analysis of separate Euler angles is not independent of marker placement, even
if performed by trained specialists.


title:
Oriented bounding boxes using multiresolution contours for fast
  interference detection of arbitrary geometry objects

abstract:
  Interference detection of arbitrary geometric objects is not a trivial task
due to the heavy computational load imposed by implementation issues. The
hierarchically structured bounding boxes help us to quickly isolate the contour
of segments in interference. In this paper, a new approach is introduced to
treat the interference detection problem involving the representation of
arbitrary shaped objects. Our proposed method relies upon searching for the
best possible way to represent contours by means of hierarchically structured
rectangular oriented bounding boxes. This technique handles 2D objects
boundaries defined by closed B-spline curves with roughness details. Each
oriented box is adapted and fitted to the segments of the contour using second
order statistical indicators from some elements of the segments of the object
contour in a multiresolution framework. Our method is efficient and robust when
it comes to 2D animations in real time. It can deal with smooth curves and
polygonal approximations as well results are present to illustrate the
performance of the new method.


title: Ring Of Real Analytic Functions on $[0,1]$

abstract:
  We consider the ring of real analytic functions defined on $[0,1]$, i.e.
$$C^{\omega}[0,1] =\lbrace f :[0,1] \longrightarrow \mathbb{R} | f \text{ is
analytic on } [0,1]\rbrace$$ In this article, we explore the nature of ideals
in this ring. It is well known that the ring $C[0,1]$ of real valued continuous
functions on $[0,1]$ has precisely the following maximal ideals: $$\text{For }
\gamma \in [0,1], M_{\gamma} := \lbrace f \in C[0,1] | f(\gamma) =0\rbrace$$ It
has been proved that each such $M_{\gamma}$ is infinitely generated, in-fact
uncountably generated. Observe that $C^{\omega}[0,1]$ is a subring of $C[0,1]$
  We prove that for any $\gamma$ in $[0,1]$, the contraction
$M^{\omega}_{\gamma}$ of $M_{\gamma}$ under the natural inclusion of
$C^{\omega}[0,1]$ in $C[0,1]$ is again a maximal ideal (of $C^{\omega}[0,1]$ ),
and these are precisely all the maximal ideals of $C^{\omega}[0,1]$. Next we
prove that each $M^{\omega}_{\gamma}$ is principal (though $M_{\gamma}$ is
uncountably generated). Surprisingly, this forces all the ideals of the ring
$C^{\omega}[0,1]$ to be singly generated, i.e. $C^{\omega}[0,1]$ is a PID.


title: The loop gravity string

abstract:
  In this work we study canonical gravity in finite regions for which we
introduce a generalisation of the Gibbons-Hawking boundary term including the
Immirzi parameter. We study the canonical formulation on a spacelike
hypersuface with a boundary sphere and show how the presence of this term leads
to an unprecedented type of degrees of freedom coming from the restoration of
the gauge and diffeomorphism symmetry at the boundary. In the presence of a
loop quantum gravity state, these boundary degrees of freedom localize along a
set of punctures on the boundary sphere. We demonstrate that these degrees of
freedom are effectively described by auxiliary strings with a 3-dimensional
internal target space attached to each puncture. We show that the string
currents represent the local frame field, that the string angular momenta
represent the area flux and that the string stress tensor represents the two
dimensional metric on the boundary of the region of interest. Finally, we show
that the commutators of these broken diffeomorphisms charges of quantum
geometry satisfy at each puncture a Virasoro algebra with central charge $c=3$.
This leads to a description of the boundary degrees of freedom in terms of a
CFT structure with central charge proportional to the number of loop punctures.
The boundary $SU(2)$ gauge symmetry is recovered via the action of the $U(1)^3$
Kac-Moody generators (associated with the string current) in a way that is the
exact analog of an infinite dimensional generalization of the Schwinger
spin-representation. We finally show that this symmetry is broken by the
presence of background curvature.


title: Matrix factorizations and curves in $\mathbb{P}^4$

abstract:
  Let $C$ be a curve in $\mathbb{P}^4$ and $X$ be a hypersurface containing it.
We show how it is possible to construct a matrix factorization on $X$ from the
pair $(C,X)$ and, conversely, how a matrix factorization on $X$ leads to curves
lying on $X$. We use this correspondence to prove the unirationality of the
Hurwitz space $\mathcal{H}_{12,8}$ and the uniruledness of the Brill-Noether
space $\mathcal{W}^1_{13,9}$. Several unirational families of curves of genus
$16 \leq g \leq 20$ in $\mathbb{P}^4$ are also exhibited.


title: Global study of nuclear modifications on parton distribution functions

abstract:
  A global analysis of nuclear medium modifications of parton distributions is
presented using deeply inelastic scattering data of various nuclear targets.
Two obtained data sets are provided for quark and gluon nuclear modification
factors, referred as nIMParton16. One is from the global fit only to the
experimental data of isospin-scalar nuclei (Set A), and the other is from the
fit to all the measured nuclear data (Set B). The scale-dependence is described
by DGLAP equations with nonlinear corrections in this work. The Fermi motion
and off-shell effect, nucleon swelling, and parton-parton recombination are
taken into account together for modeling the complicated $x$-dependence of
nuclear modification. The nuclear gluon shadowing in this paper is dynamically
generated by the QCD evolution of parton splitting and recombination processes
with zero gluon density at the input scale. Sophisticated nuclear dependence of
nuclear medium effects is studied with only two free parameters. With the
obtained free parameters from the global analysis, the nuclear modifications of
parton distribution functions of unmeasured nuclei can be predicted in our
model. Nuclear modification of deuteron is also predicted and shown with recent
measurement at JLab.


title: Well-Quasi-Ordering versus Clique-Width: New Results on Bigenic Classes

abstract:
  Daligault, Rao and Thomass\'e asked whether a hereditary class of graphs
well-quasi-ordered by the induced subgraph relation has bounded clique-width.
Lozin, Razgon and Zamaraev recently showed that this is not true for classes
defined by infinitely many forbidden induced subgraphs. However, in the case of
finitely many forbidden induced subgraphs the question remains open and we
conjecture that in this case the answer is positive. The conjecture is known to
hold for classes of graphs defined by a single forbidden induced subgraph $H$,
as such graphs are well-quasi-ordered and are of bounded clique-width if and
only if $H$ is an induced subgraph of $P_4$. For bigenic classes of graphs,
i.e. ones defined by two forbidden induced subgraphs, there are several open
cases in both classifications. In the present paper we obtain a number of new
results on well-quasi-orderability of bigenic classes, each of which supports
the conjecture.


title:
Improvement of the transport properties of a high-mobility electron
  system by intentional parallel conductance

abstract:
  We present a gating scheme to separate even strong parallel conductance from
the magneto-transport signatures and properties of a two-dimensional electron
system. By varying the electron density in the parallel conducting layer, we
can study the impact of mobile charge carriers in the vicinity of the dopant
layer on the properties of the two-dimensional electron system. It is found
that the parallel conducting layer is indeed capable to screen the remote
ionized impurity potential fluctuations responsible for the fragility of
fractional quantum Hall states.


title: Learning to Navigate in Complex Environments

abstract:
  Learning to navigate in complex environments with dynamic elements is an
important milestone in developing AI agents. In this work we formulate the
navigation question as a reinforcement learning problem and show that data
efficiency and task performance can be dramatically improved by relying on
additional auxiliary tasks leveraging multimodal sensory inputs. In particular
we consider jointly learning the goal-driven reinforcement learning problem
with auxiliary depth prediction and loop closure classification tasks. This
approach can learn to navigate from raw sensory input in complicated 3D mazes,
approaching human-level performance even under conditions where the goal
location changes frequently. We provide detailed analysis of the agent
behaviour, its ability to localise, and its network activity dynamics, showing
that the agent implicitly learns key navigation abilities.


title:
Asymptotic behavior for quadratic variations of non-Gaussian
  multiparameter Hermite random fields

abstract:
  Let $(Z^{q, H}_t)_{t \in [0, 1]^d}$ denote a $d$-parameter Hermite random
field of order $q \geq 1$ and self-similarity parameter $H = (H_1, \ldots, H_d)
\in (\frac{1}{2}, 1)^d$. This process is $H$-self-similar, has stationary
increments and exhibits long-range dependence. Particular examples include
fractional Brownian motion ($q=1$, $d=1$), fractional Brownian sheet $(q=1, d
\geq 2)$, Rosenblatt process ($q=2$, $d=1$) as well as Rosenblatt sheet $(q=2,
d \geq 2)$. For any $q \geq 2, d\geq 1$ and $H \in (\frac{1}{2}, 1)^d$ we show
in this paper that a proper normalization of the quadratic variation of $Z^{q,
H}$ converges in $L^2(\Omega)$ to a standard $d$-parameter Rosenblatt random
variable with self-similarity index $H" = 1+ (2H-2)/q$.


title: Electromagnetic Properties of a Hot and Dense Medium

abstract:
  We study the properties of an electromagnetically interacting medium in the
presence of high concentration of electrons at extremely high temperatures and
chemical potentials. We show that the electromagnetic properties of a medium
such as the electric permittivity, magnetic permeability, magnetic moments and
the propagation speed of electromagnetic waves as well as the corresponding
particle processes depend on temperature and density of the medium.
Electromagnetic properties of neutrinos are significantly modified due to their
interactions with electrons when they propagate through such a medium of hot
and dense electrons.


title:
$L_\infty$-estimates for the torsion function and $L_\infty$-growth of
  semigroups satisfying Gaussian bounds

abstract:
  We investigate selfadjoint $C_0$-semigroups on Euclidean domains satisfying
Gaussian upper bounds. Major examples are semigroups generated by second order
uniformly elliptic operators with Kato potentials and magnetic fields. We study
the long time behaviour of the $L_\infty$ operator norm of the semigroup. As an
application we prove a new $L_\infty$-bound for the torsion function of a
Euclidean domain that is close to optimal.


title: Primal-Dual Optimization for Fluids

abstract:
  We apply a novel optimization scheme from the image processing and machine
learning areas, a fast Primal-Dual method, to achieve controllable and
realistic fluid simulations. While our method is generally applicable to many
problems in fluid simulations, we focus on the two topics of fluid guiding and
separating solid-wall boundary conditions. Each problem is posed as an
optimization problem and solved using our method, which contains acceleration
schemes tailored to each problem. In fluid guiding, we are interested in
partially guiding fluid motion to exert control while preserving fluid
characteristics. With our method, we achieve explicit control over both
large-scale motions and small-scale details which is valuable for many
applications, such as level-of-detail adjustment (after running the coarse
simulation), spatially varying guiding strength, domain modification, and
resimulation with different fluid parameters. For the separating solid-wall
boundary conditions problem, our method effectively eliminates unrealistic
artifacts of fluid crawling up solid walls and sticking to ceilings, requiring
few changes to existing implementations. We demonstrate the fast convergence of
our Primal-Dual method with a variety of test cases for both model problems.


title:
Resonance fluorescence from an asymmetric quantum dot dressed by a
  bichromatic electromagnetic field

abstract:
  We present the theory of resonance fluorescence from an asymmetric quantum
dot driven by a two-component electromagnetic field with two different
frequencies, polarizations and amplitudes (bichromatic field) in the regime of
strong light-matter coupling. It follows from the elaborated theory that the
broken inversion symmetry of the driven quantum system and the bichromatic
structure of the driving field result in unexpected features of the resonance
fluorescence, including the infinite set of Mollow triplets, the quench of
fluorescence peaks induced by the dressing field, and the oscillating behavior
of the fluorescence intensity as a function of the dressing field amplitude.
These quantum phenomena are of general physical nature and, therefore, can take
place in various double-driven quantum systems with broken inversion symmetry.


title: Deep Convolutional Neural Network for Inverse Problems in Imaging

abstract:
  In this paper, we propose a novel deep convolutional neural network
(CNN)-based algorithm for solving ill-posed inverse problems. Regularized
iterative algorithms have emerged as the standard approach to ill-posed inverse
problems in the past few decades. These methods produce excellent results, but
can be challenging to deploy in practice due to factors including the high
computational cost of the forward and adjoint operators and the difficulty of
hyper parameter selection. The starting point of our work is the observation
that unrolled iterative methods have the form of a CNN (filtering followed by
point-wise non-linearity) when the normal operator (H*H, the adjoint of H times
H) of the forward model is a convolution. Based on this observation, we propose
using direct inversion followed by a CNN to solve normal-convolutional inverse
problems. The direct inversion encapsulates the physical model of the system,
but leads to artifacts when the problem is ill-posed; the CNN combines
multiresolution decomposition and residual learning in order to learn to remove
these artifacts while preserving image structure. We demonstrate the
performance of the proposed network in sparse-view reconstruction (down to 50
views) on parallel beam X-ray computed tomography in synthetic phantoms as well
as in real experimental sinograms. The proposed network outperforms total
variation-regularized iterative reconstruction for the more realistic phantoms
and requires less than a second to reconstruct a 512 x 512 image on GPU.


title: DB-Nets: on The Marriage of Colored Petri Nets and Relational Databases

abstract:
  The integrated management of business processes and mas- ter data is being
increasingly considered as a fundamental problem, by both the academia and the
industry. In this position paper, we focus on the foundations of the problem,
arguing that contemporary approaches struggle to find a suitable equilibrium
between data- and process-related aspects. We then propose db-nets, a new
formal model that balances such two pillars through the marriage of colored
Petri nets and relational databases. We invite the research community to build
on this model, discussing its potential in modeling, formal verification, and
simulation.


title:
Prediction-Correction Algorithms for Time-Varying Constrained
  Optimization

abstract:
  This paper develops online algorithms to track solutions of time-varying
constrained optimization problems. Particularly, resembling workhorse Kalman
filtering-based approaches for dynamical systems, the proposed methods involve
prediction-correction steps to provably track the trajectory of the optimal
solutions of time-varying convex problems. The merits of existing
prediction-correction methods have been shown for unconstrained problems and
for setups where computing the inverse of the Hessian of the cost function is
computationally affordable. This paper addresses the limitations of existing
methods by tackling constrained problems and by designing first-order
prediction steps that rely on the Hessian of the cost function (and do not
require the computation of its inverse). In addition, the proposed methods are
shown to improve the convergence speed of existing prediction-correction
methods when applied to unconstrained problems. Numerical simulations
corroborate the analytical results and showcase performance and benefits of the
proposed algorithms. A realistic application of the proposed method to
real-time control of energy resources is presented.


title:
The Liouville Dynamics of the q-Deformed 1-D Classical Harmonic
  Oscillator

abstract:
  The Liouville equation for the q-deformed 1-D classical harmonic oscillator
is derived for two definitions of q-deformation. This derivation is achieved by
using two different representations for the q-deformed Hamiltonian of this
oscillator corresponding to undeformed and deformed phase spaces. The resulting
Liouville equation is solved by using the method of characteristics in order to
obtain the classical probability distribution function for this system. The 2-D
and 3-D behaviors of this function are then investigated using a computer
visualization method. The results are compared with those for the classical
anharmonic oscillator. This comparison reveals that there are some similarities
between these two models, where the results for the q-deformed oscillator
exhibit similar whorl shapes that evolve with time as for the anharmonic
oscillator. It is concluded that studying the Liouville dynamics gives more
details about the physical nature of q-deformation than using the equation of
motion method. It is also concluded that this result could have reflections on
the interpretation of the quantized version of this q-deformed oscillator.


title:
Optical spectroscopy of the microquasar GRS 1758-258: a possible
  intermediate mass system?

abstract:
  Context. GRS 1758-258 is one of two prototypical microquasars towards the
Galactic Center direction discovered almost a quarter of a century ago. The
system remains poorly studied in the optical domain due to its counterpart
being a very faint and absorbed target in a crowded region of the sky. Aims.
Our aim is to investigate GRS 1758-258 in order to shed light on the nature of
the stellar binary components. In particular, the main physical parameters of
the donor star, such as the mass or the spectral type, are not yet well
constrained. Methods. GRS 1758-258 has remained so far elusive to optical
spectroscopy owing to its observational difficulties. Here, we use this
traditional tool of stellar astronomy at low spectral resolution with a 10 m
class telescope and a long slit spectrograph. Results. An improved spectrum is
obtained as compared to previous work. The quality of the data does not allow
the detection of emission or absorption features but, nevertheless, we manage
to partially achieve our aims comparing the de-reddened continuum with the
spectral energy distribution expected from an irradiated disc model and
different donor star templates. Conclusions. We tentatively propose that GRS
1758-258 does not host a giant star companion. Instead, a main sequence star
with mid-A spectral type appears to better agree with our data. The main
impacts of this finding are the possibility that we are dealing with an
intermediate mass system and, in this case, the prediction of an orbital period
significantly shorter than previously proposed.


title: Amplitudes ratios in $\rho^0$ leptoproductions and GPDs

abstract:
  We investigate exclusive leptoproduction of $\rho^0$ meson. These reactions
were analyzed within the factorizing handbag approach. In our model good
agreement of observables for light meson production with experimental data in a
wide energy range was found.
  Using the model results we calculate the ratio of different helicity
amplitudes for a transversely polarized proton target to the leading twist
longitudinal amplitude. Our results are close to the amplitude ratios measured
by HERMES.


title: A quotient of the Lubin-Tate tower

abstract:
  In this article we show that the quotient of the Lubin-Tate space at infinite
level by the Borel subgroup of upper triangular matrices in GL(2,Q_p) exists as
a perfectoid space. As an application we show that Scholze's functor
H^i_et(P^1,F(pi)) is concentrated in degree one whenever pi is a principal
series representation or a twist of the Steinberg representation of GL(2,Q_p).


title:
Improved Discrete-Time Kalman Filtering within Singular Value
  Decomposition

abstract:
  The paper presents a new Kalman filter (KF) implementation useful in
applications where the accuracy of numerical solution of the associated Riccati
equation might be crucially reduced by influence of roundoff errors. Since the
appearance of the KF in 1960s, it has been recognized that the factored-form of
the KF is preferable for practical implementation. The most popular and
beneficial techniques are found in the class of square-root algorithms based on
the Cholesky decomposition of error covariance matrix. Another important matrix
factorization method is the singular value decomposition (SVD) and, hence,
further encouraging implementations might be found under this approach. The
analysis presented here exposes that the previously proposed SVD-based KF
variant is still sensitive to roundoff errors and poorly treats ill-conditioned
situations, although the SVD-based strategy is inherently more stable than the
conventional KF approach. In this paper we design a new SVD-based KF
implementation for enhancing the robustness against roundoff errors, provide
its detailed derivation, and discuss the numerical stability issues. A set of
numerical experiments are performed for comparative study. The obtained results
illustrate that the new SVD-based method is algebraically equivalent to the
conventional KF and to the previously proposed SVD-based method, but it
outperforms the mentioned techniques for estimation accuracy in ill-conditioned
situations.


title:
Real-time observation of the isothermal crystallization kinetics in a
  deeply supercooled liquid

abstract:
  Below the melting temperature $T_m$ crystals are the stable phase of typical
elemental or molecular systems. However, cooling down a liquid below $T_m$,
crystallization is anything but inevitable. The liquid can be supercooled,
eventually forming a glass below the glass transition temperature $T_g$.
Despite their long lifetimes and the presence of strong barriers that produces
an apparent stability, supercooled liquids and glasses remain intrinsically
metastable state and thermodynamically unstable towards the crystal. Here we
investigated the isothermal crystallization kinetics of the prototypical strong
glassformer GeO$_2$ in the deep supercooled liquid at 1100 K, about half-way
between $T_m$ and $T_g$. The crystallization process has been observed through
time-resolved neutron diffraction for about three days. Data show a continuous
reorganization of the amorphous structure towards the alpha-quartz phase with
the final material composed by crystalline domains plunged into a low-density,
residual amorphous matrix. A quantitative analysis of the diffraction patterns
allows determining the time evolution of the relative fractions of crystal and
amorphous, that was interpreted through an empirical model for the
crystallization kinetics. This approach provides a very good description of the
experimental data and identifies a predator-prey-like mechanism between crystal
and amorphous, where the density variation acts as blocking barrier.


title: Homogeneous rank one perturbations

abstract:
  A holomorphic family of closed operators with a rank one perturbation given
by the function $x^{\frac{m}{2}}$ is studied. The operators can be used in a
toy model of renormalization group.


title: Incommensurate spiral order from double exchange interactions

abstract:
  The double exchange model describing interactions of itinerant electrons with
localized spins is usually used to explain ferromagnetism in metals. We show
that for a variety of crystal lattices of different dimensionalities and for a
wide range of model parameters the ferromagnetic state is unstable against a
non-collinear spiral magnetic order. We revisit the phase diagram of the double
exchange model on a triangular lattice and show in a large part of the diagram
the incommensurate spiral state has a lower energy than the previously
discussed commensurate states. These results indicate that double exchange
systems are inherently frustrated and can host unconventional spin orders.


title: Supergravity with Doubled Spacetime Structure

abstract:
  Double Field Theory (DFT) is a low-energy effective theory of a manifestly
$O(D,D)$ invariant formulation of the closed string theory when toroidally
compactified dimensions are present. The theory is based on a doubled spacetime
structure and, in order to preserve the gauge symmetry provided by the
invariance under generalized diffeomorphisms, a constraint has to be imposed on
fields and gauge parameters. In this paper, we propose a DFT-inspired
Supergravity by using a suitable {\em star product} that implements such
constraint and the corresponding algebraic structure is explored. We get a
consistent DFT in which also an orthogonality condition of momenta is necessary
for having a closed gauge algebra. In constructing this theory, we start from
the simplest case of doubling one spatial dimension where the action is
uniquely determined, without ambiguities, by the gauge symmetry. Then, the
extension to the generic $O(D, D)$ case is presented. The result is consistent
with the closed string field theory.


title:
Quantifying statistical uncertainties in ab initio nuclear physics using
  Lagrange multipliers

abstract:
  Theoretical predictions need quantified uncertainties for a meaningful
comparison to experimental results. This is an idea which presently permeates
the field of theoretical nuclear physics. In light of the recent progress in
estimating theoretical uncertainties in ab initio nuclear physics, we here
present and compare methods for evaluating the statistical part of the
uncertainties. A special focus is put on the (for the field) novel method of
Lagrange multipliers (LM). Uncertainties from the fit of the nuclear
interaction to experimental data are propagated to a few observables in
light-mass nuclei to highlight any differences between the presented methods.
The main conclusion is that the LM method is more robust, while covariance
based methods are less demanding in their evaluation.


title: A sharp $k$-plane Strichartz inequality for the Schr\"odinger equation

abstract:
  We prove that $$ \|X(|u|^2)\|_{L^3_{t,\ell}}\leq
C\|f\|_{L^2(\mathbb{R}^2)}^2, $$ where $u(x,t)$ is the solution to the linear
time-dependent Schr\"odinger equation on $\mathbb{R}^2$ with initial datum $f$,
and $X$ is the (spatial) X-ray transform on $\mathbb{R}^2$. In particular, we
identify the best constant $C$ and show that a datum $f$ is an extremiser if
and only if it is a gaussian. We also establish bounds of this type in higher
dimensions $d$, where the X-ray transform is replaced by the $k$-plane
transform for any $1\leq k\leq d-1$. In the process we obtain sharp $L^2(\mu)$
bounds on Fourier extension operators associated with certain high-dimensional
spheres, involving measures $\mu$ supported on natural "co-$k$-planarity" sets.


title:
Orbital breathing effects in the computation of x-ray d-ion spectra in
  solids by ab initio wave-function-based methods

abstract:
  In existing theoretical approaches to core-level excitations of
transition-metal ions in solids relaxation and polarization effects due to the
inner core hole are often ignored or described phenomenologically. Here we set
up an ab initio computational scheme that explicitly accounts for such physics
in the calculation of x-ray absorption and resonant inelastic x-ray scattering
spectra. Good agreement is found with experimental transition-metal $L$-edge
data for the strongly correlated $d^9$ cuprate Li$_2$CuO$_2$, for which we
determine the absolute scattering intensities. The newly developed methodology
opens the way for the investigation of even more complex $d^n$ electronic
structures of group VI B to VIII B correlated oxide compounds.


title:
Analysis of a mathematical model for tumor growth with Gibbs-Thomson
  relation

abstract:
  In this paper we study a mathematical model for the growth of nonnecrotic
solid tumor. The tumor is assumed to be radially symmetric and its radius R(t)
is an unknown function of time t as tumor growth, and the model is in the form
of a free boundary problem. The feature of the model is that a Gibbs-Thomson
relation is taken into account, which resulting an interesting phenomenon that
there exist two stationary solutions (depending on the model parameters). The
global existence and uniqueness of solution are established. By denoting c the
ratio of the diffusion time scale to the tumor doubling time scale, we prove
that for sufficiently small c>0, the stationary solution with the larger radius
is asymptotically stable, and the other smaller one is unstable.


title: Reaching the ideal glass transition by aging polymer films

abstract:
  Searching for the ideal glass transition, we exploit the ability of glassy
polymer films to explore low energy states in remarkably short time scales. We
use 30 nm thick polystyrene (PS) films, which in the supercooled state
basically display the bulk polymer equilibrium thermodynamics and dynamics. We
show that in the glassy state, this system exhibits two mechanisms of
equilibrium recovery. The faster one, active well below the kinetic glass
transition temperature ($T_g$), allows massive enthalpy recovery. This implies
that the 'fictive' temperature ($T_f$) reaches values as low as the predicted
Kauzmann temperature ($T_K$) for PS. Once the thermodynamic state corresponding
to $T_f = T_K$ is reached, no further decrease of enthalpy is observed. This is
interpreted as a signature of the ideal glass transition.


title: Hall algebras and Donaldson-Thomas invariants

abstract:
  This is a survey article on Hall algebras and their applications to the study
of motivic invariants of moduli spaces of coherent sheaves on Calabi-Yau
threefolds. It is a write-up of my talks at the 2015 Salt Lake City AMS Summer
Research Institute and will appear in the Proceedings. The ideas presented here
are mostly due to Joyce, Kontsevich, Reineke, Soibelman and Toda.


title: Riemann-Hilbert problems from Donaldson-Thomas theory

abstract:
  We study a class of Riemann-Hilbert problems arising naturally in
Donaldson-Thomas theory. In certain special cases we show that these problems
have unique solutions which can be written explicitly as products of gamma
functions. We briefly explain connections with Gromov-Witten theory and exact
WKB analysis.


title: A model for structured information representation in neural networks

abstract:
  Humans possess the capability to reason at an abstract level and to structure
information into abstract categories, but the underlying neural processes have
remained unknown. Experimental evidence has recently emerged for the
organization of an important aspect of abstract reasoning: for assigning words
to semantic roles in a sentence, such as agent (or subject) and patient (or
object). Using minimal assumptions, we show how such a binding of words to
semantic roles emerges in a generic spiking neural network through Hebbian
plasticity. The resulting model is consistent with the experimental data and
enables new computational functionalities such as structured information
retrieval, copying data, and comparisons. It thus provides a basis for the
implementation of more demanding cognitive computations by networks of spiking
neurons.


title:
Design and Analysis of Compressive Antenna Arrays for Direction of
  Arrival Estimation

abstract:
  In this paper we investigate the design of compressive antenna arrays for
direction of arrival (DOA) estimation that aim to provide a larger aperture
with a reduced hardware complexity by a linear combination of the antenna
outputs to a lower number of receiver channels. We present a basic receiver
architecture of such a compressive array and introduce a generic system model
that includes different options for the hardware implementation. We then
discuss the design of the analog combining network that performs the receiver
channel reduction, and propose two design approaches. The first approach is
based on the spatial correlation function which is a low-complexity scheme that
in certain cases admits a closed-form solution. The second approach is based on
minimizing the Cramer-Rao Bound (CRB) with the constraint to limit the
probability of false detection of paths to a pre-specified level. Our numerical
simulations demonstrate the superiority of the proposed optimized compressive
arrays compared to the sparse arrays of the same complexity and to compressive
arrays with randomly chosen combining kernels.


title:
A block lower triangular preconditioner for a class of complex symmetric
  system of linear equations

abstract:
  We present a block lower triangular (BLT) preconditioner to accelerate the
convergence of nthe Krylov subspace iterative methods, such as generalized
minimal residual (GMRES), for solving a broad class of complex symmetric system
of linear equations. We analyze the eigenvalues distribution of preconditioned
coefficient matrix. Numerical experiments are given to demonstrate the
effectiveness of the BLT preconditioner.


title: Experimental evidence for Wigner's tunneling time

abstract:
  Tunneling of a particle through a potential barrier remains one of the most
remarkable quantum phenomena. Owing to advances in laser technology, electric
fields comparable to those electrons experience in atoms are readily generated
and open opportunities to dynamically investigate the process of electron
tunneling through the potential barrier formed by the superposition of both
laser and atomic fields. Attosecond-time and angstrom-space resolution of the
strong laser-field technique allow to address fundamental questions related to
tunneling, which are still open and debated: Which time is spent under the
barrier and what momentum is picked up by the particle in the meantime? In this
combined experimental and theoretical study we demonstrate that for
strong-field ionization the leading quantum mechanical Wigner treatment for the
time resolved description of tunneling is valid. We achieve a high sensitivity
on the tunneling barrier and unambiguously isolate its effects by performing a
differential study of two systems with almost identical tunneling geometry.
Moreover, working with a low frequency laser, we essentially limit the
non-adiabaticity of the process as a major source of uncertainty. The agreement
between experiment and theory implies two substantial corrections with respect
to the widely employed quasiclassical treatment: In addition to a non-vanishing
longitudinal momentum along the laser field-direction we provide clear evidence
for a non-zero tunneling time delay. This addresses also the fundamental
question how the transition occurs from the tunnel barrier to free space
classical evolution of the ejected electron.


title: Holographic Floquet states: (I) A strongly coupled Weyl semimetal

abstract:
  Floquet states can be realized in quantum systems driven by continuous
time-periodic perturbations. It is known that a state known as the Floquet Weyl
semimetal can be realized when free Dirac fermions are placed in a rotating
electric field. What will happen if strong interaction is introduced to this
system? Will the interaction wash out the characteristic features of Weyl
semimetals such as the Hall response? Is there a steady state and what is its
thermodynamic behavior? We answer these questions using AdS/CFT correspondence
in the $\mathcal{N}=2$ supersymmetric massless QCD in a rotating electric field
in the large $N_c$ limit realizing the first example of a "holographic Floquet
state". In this limit, gluons not only mediate interaction, but also act as an
energy reservoir and stabilize the nonequilibrium steady state (NESS). We
obtain the electric current induced by a rotating electric field: In the high
frequency region, the Ohm's law is satisfied, while we recover the DC nonlinear
conductivity at low frequency, which was obtained holographically in a previous
work. The thermodynamic properties of the NESS, e.g., fluctuation-dissipation
relation, is characterized by the effective Hawking temperature that is defined
from the effective horizon giving a holographic meaning to the "periodic
thermodynamic" concept. In addition to the strong (pump) rotating electric
field, we apply an additional weak (probe) electric field in the spirit of the
pump-probe experiments done in condensed matter experiments. Weak DC and AC
probe analysis in the background rotating electric field shows Hall currents as
a linear response, therefore the Hall response of Floquet Weyl semimetals
survives at the strong coupling limit. We also find frequency mixed response
currents, i.e., a heterodyning effect, characteristic to periodically driven
Floquet systems.

categories: hep-th cond-mat.mes-hall cond-mat.str-el gr-qc


title:
An improved effective-one-body model of spinning, nonprecessing binary
  black holes for the era of gravitational-wave astrophysics with advanced
  detectors

abstract:
  We improve the accuracy of the effective-one-body (EOB) waveforms that were
employed during the first observing run of Advanced LIGO for binaries of
spinning, nonprecessing black holes by calibrating them to a set of 141
numerical-relativity (NR) waveforms. The NR simulations expand the domain of
calibration towards larger mass ratios and spins, as compared to the previous
EOBNR model. Merger-ringdown waveforms computed in black-hole perturbation
theory for Kerr spins close to extremal provide additional inputs to the
calibration. For the inspiral-plunge phase, we use a Markov-chain Monte Carlo
algorithm to efficiently explore the calibration space. For the merger-ringdown
phase, we fit the NR signals with phenomenological formulae. After
extrapolation of the calibrated model to arbitrary mass ratios and spins, the
(dominant-mode) EOBNR waveforms have faithfulness --- at design Advanced-LIGO
sensitivity --- above $99\%$ against all the NR waveforms, including 16
additional waveforms used for validation, when maximizing only on initial phase
and time. This implies a negligible loss in event rate due to modeling for
these binary configurations. We find that future NR simulations at mass ratios
$\gtrsim 4$ and double spin $\gtrsim 0.8$ will be crucial to resolve
discrepancies between different ways of extrapolating waveform models. We also
find that some of the NR simulations that already exist in such region of
parameter space are too short to constrain the low-frequency portion of the
models. Finally, we build a reduced-order version of the EOBNR model to speed
up waveform generation by orders of magnitude, thus enabling intensive
data-analysis applications during the upcoming observation runs of Advanced
LIGO.


title:
K2-60b and epic 216468514b. A sub-jovian and a jovian planet from the k2
  mission

abstract:
  We report the characterization and independant detection of K2-60b, as well
as the detection and characterization of EPIC 216468514b, two transiting hot
gaseous planets from the K2 space mission. We confirm the planetary nature of
the two systems and determine their fundamental parameters combining the K2
time-series data with FIES@NOT and HARPS-N@TNG spectroscopic observations.
K2-60b has a radius of 0.683 +/- 0.037 RJup and a mass of 0.426 +/- 0.037 MJup
and orbits a G4V star with an orbital period of 3.00267 +/- 0.00006 days. EPIC
216468514b has a radius of 1.44 +/- 0.15RJup and a mass of 0.84 +/- 0.08 MJup
and orbits an F9 IV star every 3.31392 +/- 0.00002 days. K2-60b is among the
few planets at the edge of the so-called "desert" of short-period sub Jovian
planets. EPIC 216468514b is a highly inflated Jovian planet orbiting an evolved
star about to leave the main sequence.


title: Asymptotic density of Catalan numbers modulo 3 and powers of 2

abstract:
  We establish the asymptotic density of the Catalan numbers modulo 3 and
modulo powers of 2.


title:
Global helioseismology (WP4.1): From the Sun to the stars & solar
  analogs

abstract:
  Sun-as-a star observations put our star as a reference for stellar
observations. Here, I review the activities in which the SPACEINN global
seismology team (Working Package WP4.1) has worked during the past 3 years. In
particular, we will explain the new deliverables available on the SPACEINN
seismic+ portal. Moreover, special attention will be given to surface dynamics
(rotation and magnetic fields). After characterizing the rotation and the
magnetic properties of around 300 solar-like stars and defining proper metrics
for that, we use their seismic properties to characterize 18 solar analogues
for which we study their surface magnetic and seismic properties. This allows
us to put the Sun into context compared to its siblings.


title: The number of parking functions with center of a given length

abstract:
  Let $1\leq r\leq n$ and suppose that, when the Depth-first Search Algorithm
is applied to a given rooted labelled tree on $n+1$ vertices, exactly $r$
vertices are visited before backtracking. Let $R$ be the set of trees with this
property. We count the number of elements of $R$.
  For this purpose, we first consider a bijection, due to Parkinson, Yang and
Yu, that maps $R$ onto the set of parking function with center (defined by the
authors in a previous article) of size $r$. A second bijection maps this set
onto the set of parking functions with run $r$, a property that we introduce
here. We then prove that the number of length $n$ parking functions with a
given run is the number of length $n$ rook words (defined by Leven, Rhoades and
Wilson) with the same run. This is done by counting related lattice paths in a
ladder-shaped region. We finally count the number of length $n$ rook words with
run $r$, which is the answer to our initial question.


title:
Advection of a passive scalar field by turbulent compressible fluid:
  renormalization group analysis near $d = 4$

abstract:
  The field theoretic renormalization group (RG) and the operator product
expansion (OPE) are applied to the model of a density field advected by a
random turbulent velocity field. The latter is governed by the stochastic
Navier-Stokes equation for a compressible fluid. The model is considered near
the special space dimension $d = 4$. It is shown that various correlation
functions of the scalar field exhibit anomalous scaling behaviour in the
inertial-convective range. The scaling properties in the RG+OPE approach are
related to fixed points of the renormalization group equations. In comparison
with physically interesting case $d = 3$, at $d = 4$ additional Green function
has divergences which affect the existence and stability of fixed points. From
calculations it follows that a new regime arises there and then by continuity
moves into $d = 3$. The corresponding anomalous exponents are identified with
scaling dimensions of certain composite fields and can be systematically
calculated as series in $y$ (the exponent, connected with random force) and
$\epsilon=4-d$. All calculations are performed in the leading one-loop
approximation.


title:
Energy loss spectroscopy of Buckminster C60 with twisted electrons:
  Influence of orbital angular momentum transfer on plasmon generation

abstract:
  Recent experimental progress in creating and controlling singular electron
beams that carry orbital angular momentum allows for new types of local
spectroscopies. We theoretically investigate the twisted-electron energy loss
spectroscopy (EELS) from the C60 fullerene. Of particular interest are the
strong multipolar collective excitations and their selective response to the
orbital angular momentum of the impinging electron beam. Based on ab-initio
calculations for the collective response we compute EELS signals with twisted
electron beams and uncover the interplay between the plasmon polarity and the
amount of angular momentum transfer.

categories: cond-mat.mes-hall cond-mat.str-el physics.atm-clus physics.chem-ph


title: A quark model study of strong decays of $X\left( 3915\right) $

abstract:
  Strong decays of $X\left( 3915\right) $ are analyzed from two quark model
descriptions of $X\left( 3915\right) $, a conventional one in terms of the
Cornell potential and an unconventional one from a Generalized Screened
potential. We conclude that the experimental suppression of the OZI allowed
decay $X\left( 3915\right) \rightarrow D\overline{D}$ might be explained in
both cases as due to the momentum dependence of the decay amplitude. However,
the experimental significance of the OZI forbidden decay $X\left( 3915\right)
\rightarrow\omega J/\psi$ could favor an unconventional description.