title: Micromegas for dark matter searches: CAST/IAXO & TREX-DM

abstract:
  The most compelling candidates for Dark Matter to day are WIMPs and axions.
The applicability of gasesous Time Projection Chambers (TPCs) with Micromesh
Gas Structures (Micromegas) to the search of these particles is explored within
this work. Both particles would produce an extremely low rate at very low
energies in particle detectors. Micromegas detectors can provide both low
background rates and low en- ergy threshold, due to the high granularity,
radiopurity and uniformity of the readout. Small (few cm wide) Micromegas
detectors are used to image the axion-induced x-ray signal expected in the CERN
Axion Solar Telescope (CAST) experiment. We show the background levels obtained
in CAST and the prospects to further reduce them to the values required by the
Internation Axion Observatory (IAXO). We also present TREX-DM, a scaled-up
version of the Micromegas used in axion research, but this time dedicated to
the low-mass WIMP detection. TREX-DM is a high-pressure Micromegas-based TPC
designed to host a few hundreds of grams of light nuclei (argon or neon) with
energy thresholds potentially at the level of 100 eV. The detector is described
in detail, as well as the results of the commissioning and characterization
phase on surface. Besides, the back- ground model of TREX-DM is presented,
along with the anticipated sensitivity of this search, which could go beyond
current experimental limits.


title: On Buffer-Aided Multiple-Access Relay Channel

abstract:
  The paper treats uplink scenario where M user equipments (UEs) send to a Base
Station (BS), possibly via a common Relay Station (RS) that is equipped with a
buffer. This is a multiple-access relay channel (MARC) aided by a buffer. We
devise a protocol in which the transmission mode is selected adaptively, using
the buffer at the RS in order to maximize the average system throughput. We
consider the general case in which the RS and the BS can have limits on the
maximal number of transmitters that can be received over the multiple access
channel. In each slot there are three type possible actions: (A1) multiple UEs
transmit at rates that enable BS to decode them (A2) multiple UEs transmit, the
BS can only decode the messages partially, while the RS completely; (A3) RS
forwards the side information to BS about the partially decoded messages, which
are going to be combined and decoded entirely at the BS, while simultaneously a
number of UEs sends new messages to the BS. The results show that the adaptive
selection of direct and buffer-aided relay transmissions leads to significant
average throughput gains.


title: Reversible feedback confinement

abstract:
  We present a feedback protocol that is able to confine a system to a single
micro-state without heat dissipation. The protocol adjusts the Hamiltonian of
the system in such a way that the Bayesian posterior distribution after
measurement is in equilibrium. As a result, the whole process satisfies
feedback reversibility -- the process is indistinguishable from its time
reversal -- and assures the lowest possible dissipation for confinement. In
spite of the whole process being reversible it can surprisingly be implemented
in finite time. We illustrate the idea with a Brownian particle in a harmonic
trap with increasing stiffness and present a general theory of reversible
feedback confinement for systems with discrete states.


title:
Drifting states and synchronization induced chaos in autonomous networks
  of excitable neurons

abstract:
  The study of balanced networks of excitatory and inhibitory neurons has led
to several open questions. On the one hand it is yet unclear whether the
asynchronous state observed in the brain is autonomously generated, or if it
results from the interplay between external drivings and internal dynamics. It
is also not known, which kind of network variabilities will lead to irregular
spiking and which to synchronous firing states. Here we show how isolated
networks of purely excitatory neurons generically show asynchronous firing
whenever a minimal level of structural variability is present together with a
refractory period. Our autonomous networks are composed of excitable units, in
the form of leaky integrators spiking only in response to driving inputs. For a
non-uniform network, composed exclusively of excitatory neurons, we find a rich
repertoire of self-induced dynamical states, including asynchronous drifting
states, fully synchronized, or mixed, containing both drifting and synchronized
components. The individual neurons considered are excitable and hence do not
dispose of intrinsic natural firing frequencies. An effective network-wide
distribution of natural frequencies is however generated autonomously through
self-consistent feedback loops. We find two types of asynchronous activity,
with the individual neurons spiking regularly in the pure drifting state,
albeit with a continuous distribution of firing frequencies. The activity of
the drifting component, however, becomes irregular in the mixed state, due to
the periodic driving of the synchronized component. We propose a new tool for
the study of chaos in spiking neural networks, which consists of an analysis of
the time series of pairs of consecutive interspike intervals. In this space, we
show that a strange attractor with a fractal dimension is formed.


title:
Optimal combination of energy storages for prospective power supply
  systems based on Renewable Energy Sources

abstract:
  Prospective power supply systems based on Renewable Energy Sources require
measures to balance power generation and load at all times. The utilisation of
storage devices and backup power plants is widely suggested for this purpose,
whereas the best combination is still to be found. In this work, we present a
modelling approach to systematically study scenarios of future power supply
systems with a high share of electricity originating from wind and solar
resources. By considering backup as a subordinate source of electricity with
energy-only costs, the approach is independent of the actual full-load hours of
the backup power plants. Applying the approach to multi-year meteorological
data for Germany, cost-optimised combinations of storage devices and backup
power are identified. We find that even in scenarios with significant excess
generation capacities there is a need for storage devices or backup power
plants with discharging power on the same order as the average load to balance
the system at all times. Furthermore, these capacities seem to be required in
some years of the multi-year period only. Our results imply that the societal
need of having electricity available at all times can likely be satisfied by
installing over-capacities only, whereas a balance has to be found between
installing additional backup or storage or generation capacities.


title:
Highly efficient and tuneable spin-to-charge conversion through Rashba
  coupling at oxide interfaces

abstract:
  The spin-orbit interaction couples the electrons' motion to their spin.
Accordingly, passing a current in a material with strong spin-orbit coupling
generates a transverse spin current (spin Hall effect, SHE) and vice-versa
(inverse spin Hall effect, ISHE). The emergence of SHE and ISHE as
charge-to-spin interconversion mechanisms offers a variety of novel spintronics
functionalities and devices, some of which do not require any ferromagnetic
material. However, the interconversion efficiency of SHE and ISHE (spin Hall
angle) is a bulk property that rarely exceeds ten percent, and does not take
advantage of interfacial and low-dimensional effects otherwise ubiquitous in
spintronics hetero- and mesostructures. Here, we make use of an
interface-driven spin-orbit coupling mechanism - the Rashba effect - in the
oxide two-dimensional electron system (2DES) LaAlO3/SrTiO3 to achieve
spin-to-charge conversion with unprecedented efficiency. Through spin-pumping,
we inject a spin current from a NiFe film into the oxide 2DES and detect the
resulting charge current, which can be strongly modulated by a gate voltage. We
discuss the amplitude of the effect and its gate dependence on the basis of the
electronic structure of the 2DES.


title:
Evaluation of student proficiency through a multidimensional finite
  mixture IRT model

abstract:
  In certain academic systems, a student can enroll for an exam immediately
after the end of the teaching period or can postpone it to any later
examination session, so that the grade is missing until the exam is not
attempted. We propose an approach for the evaluation in itinere of a student's
proficiency accounting also for non-attempted exams. The approach is based on
considering each exam as an item, so that responding to the item amounts to
attempting the exam, and on an Item Response Theory model that includes two
latent variables corresponding to the student's ability and the propensity to
attempt the exam. In this way, we explicitly account for non-ignorable missing
observations as the indicators of item response also contribute to measure the
ability. The two latent variables are assumed to have a discrete distribution
defining latent classes of students that are homogeneous in terms of ability
and priority assigned to exams. The model, which also allows for individual
covariates in its structural part, is fitted by the Expectation-Maximization
algorithm. The approach is illustrated through the analysis of data about the
first-year exams of freshmen of the School of Economics at the University of
Florence (Italy).


title: Induced QCD I: Theory

abstract:
  We explore an alternative discretization of continuum SU(N_c) Yang-Mills
theory on a Euclidean spacetime lattice, originally introduced by Budzcies and
Zirnbauer. In this discretization the self-interactions of the gauge field are
induced by a path integral over N_b auxiliary boson fields, which are coupled
linearly to the gauge field. The main progress compared to earlier approaches
is that N_b can be as small as N_c. In the present paper we (i) extend the
proof that the continuum limit of the new discretization reproduces Yang-Mills
theory in two dimensions from gauge group U(N_c) to SU(N_c), (ii) derive
refined bounds on N_b for non-integer values, and (iii) perform a perturbative
calculation to match the bare parameter of the induced gauge theory to the
standard lattice coupling. In follow-up papers we will present numerical
evidence in support of the conjecture that the induced gauge theory reproduces
Yang-Mills theory also in three and four dimensions, and explore the
possibility to integrate out the gauge fields to arrive at a dual formulation
of lattice QCD.


title:
Systematic study on probable projectile-target combinations for the
  synthesis of the $^{302}$120 superheavy nucleus

abstract:
  Probable projectile-target combinations for the synthesis of superheavy
element $^{302}$120 have been studied taking Coulomb and proximity potential as
the interaction barrier. The probabilities of compound nucleus formation, PCN
for the projectile-target combinations found in the cold reaction valley of
$^{302}$120 are estimated. At energies near and above the Coulomb barrier, we
have calculated the capture, fusion and evaporation residue cross sections for
the reactions of all the probable projectile-target combinations so as to
predict the most promising projectile-target combinations for the synthesis of
SHE $^{302}$120 in heavy ion fusion reactions. The calculated fusion and
evaporation cross section for the more asymmetric (hotter) projectile-target
combination is found to be higher than the less asymmetric (colder)
combination. It can be seen from the nature of quasi-fission barrier height,
mass asymmetry, probability of compound nucleus formation, survival probability
and excitation energy, the systems $^{44}$Ar + $^{258}$No, $^{46}$Ar +
$^{256}$No, $^{48}$Ca + $^{254}$Fm, $^{50}$Ca + $^{252}$Fm, $^{54}$Ti +
$^{248}$Cf, $^{58}$Cr + $^{244}$Cm in the deep region I of cold reaction
valley, and the systems $^{62}$Fe + $^{240}$Pu, $^{64}$Fe + $^{238}$Pu,
$^{68}$Ni + $^{234}$U, $^{70}$Ni + $^{232}$U, $^{72}$Ni + $^{230}$U, $^{74}$Zn
+ $^{228}$Th in the other cold valleys are identified as the better
projectile-target combinations for the synthesis of $^{302}$120. Our prediction
on the synthesis of $^{302}$120 superheavy nuclei using the combinations
$^{54}$Cr+$^{248}$Cm, $^{58}$Fe+$^{244}$Pu, $^{64}$Ni+$^{238}$U and
$^{50}$Ti+$^{249}$Cf are compared with available experimental data and other
theoretical predictions.


title: Topology and Quantum States: the Electron-Monopole system

abstract:
  This paper starts by describing the dynamics of the electron-monopole system
at both classical and quantum level by a suitable reduction procedure. This
suggests, in order to realise the space of states for quantum systems which are
classically described on topologically non trivial configuration spaces, to
consider Hilbert spaces of exterior differential forms. Among the advantages of
this formulation, we present in the case of the group ${\rm SU}(2)$, how it is
possible to obtain all unitary irreducible representations on such a Hilbert
space, and how it is possible to write scalar Dirac type operators, following
an idea by K\"ahler.


title:
Noncommutative gravity and the relevance of the $\theta$-constant
  deformation

abstract:
  In this Letter we construct the noncommutative (NC) gravity model on the
$\theta$-constant NC space-time. We start from the NC $SO(2,3)_\star$ gauge
theory and use the enveloping algebra approach and the Seiberg-Witten map to
construct the effective NC gravity action. The action and the equations of
motion are expanded up to second order in the deformation parameter. The
equations of motion show that the noncommutativity plays a role of a source for
the curvature and/or torsion. Finally, we calculate the NC corrections to the
Minkowski space-time and we show that in the presence of noncommutativity
Minkowski space-time becomes curved, but remains torsion-free. The breaking of
diffeomorphism invariance is understood in terms of the preferred coordinate
system. We show that the coordinates we are using are the Fermi normal
coordinates. This suggests that the natural coordinate system in which one
should study NC gravity is given by the Fermi normal coordinates.


title: Balancing building and maintenance costs in growing transport networks

abstract:
  The costs associated to the length of links impose unavoidable constraints to
the growth of natural and artificial transport networks. When future network
developments can not be predicted, building and maintenance costs require
competing minimization mechanisms, and can not be optimized simultaneously.
Hereby, we study the interplay of building and maintenance costs and its impact
on the growth of transportation networks through a non-equilibrium model of
network growth. We show cost balance is a sufficient ingredient for the
emergence of tradeoffs between the network's total length and transport
effciency, of optimal strategies of construction, and of power-law temporal
correlations in the growth history of the network. Analysis of empirical ant
transport networks in the framework of this model suggests different ant
species may adopt similar optimization strategies.


title: The numbers of powers in the Tribonacci sequence

abstract:
  The Tribonacci sequence $\mathbb{T}$ is the fixed point of the substitution
$\sigma(a)=ab$, $\sigma(b)=ac$, $\sigma(c)=a$. The prefix of $\mathbb{T}$ of
length $n$ is denoted by $\mathbb{T}[1,n]$. The main result is threefold, we
give: (1) explicit expressions of the numbers of distinct squares and cubes in
$\mathbb{T}[1,n]$; (2) algorithms for counting the numbers of repeated squares
and cubes in $\mathbb{T}[1,n]$; (3) a discussion about $\alpha$-powers in
$\mathbb{T}[1,n]$ for $\alpha\geq2$ and $n\geq1$.


title:
Bose glass behavior in (Yb$_{1-x}$Lu$_x$)$_4$As$_3$ representing the
  randomly diluted quantum spin-1/2 chains

abstract:
  The site-diluted compound (Yb$_{1-x}$Lu$_x$)$_4$As$_3$ is a scarce
realization of the linear Heisenberg antiferromagnet partitioned into
finite-size segments and is an ideal model compound for studying
field-dependent effects of quenched disorder in the one-dimensional
antiferromagnets. It differentiates from the systems studied so far in two
aspects - the type of randomness and the nature of the energy gap in the pure
sample. We have measured the specific heat of single-crystal
(Yb$_{1-x}$Lu$_x$)$_4$As$_3$ in magnetic fields up to 19.5 T. The contribution
$C_{\perp}$ arising from the magnetic subsystem in an applied magnetic field
perpendicular to the chains is determined. Compared to pure Yb$_4$As$_3$, for
which $C_{\perp}$ indicates a gap opening, for diluted systems a
non-exponential decay is found at low temperatures which is consistent with the
thermodynamic scaling of the specific heat established for a Bose-glass phase.


title:
Explicit formulas for enumeration of lattice paths: basketball and the
  kernel method

abstract:
  This article deals with the enumeration of directed lattice walks on the
integers with any finite set of steps, starting at a given altitude $j$ and
ending at a given altitude $k$, with additional constraints such as, for
example, to never attain altitude $0$ in-between. We first discuss the case of
walks on the integers with steps $-h, \dots, -1, +1, \dots, +h$. The case $h=1$
is equivalent to the classical Dyck paths, for which many ways of getting
explicit formulas involving Catalan-like numbers are known. The case $h=2$
corresponds to "basketball" walks, which we treat in full detail. Then we move
on to the more general case of walks with any finite set of steps, also
allowing some weights/probabilities associated with each step. We show how a
method of wide applicability, the so-called "kernel method", leads to explicit
formulas for the number of walks of length $n$, for any $h$, in terms of nested
sums of binomials. We finally relate some special cases to other combinatorial
problems, or to problems arising in queuing theory.


title: KIC 2831097 - A 2-year orbital-period RR Lyrae binary candidate

abstract:
  We report the discovery of a new Kepler first-overtone RR Lyrae pulsator, KIC
2831097. The pulsation shows large, 0.1 d amplitude, systematic phase
variations that can be interpreted as light travel-time effect caused by
orbital motion in a binary system, superimposed on a linear pulsation-period
decrease. The assumed eccentric (e=0.47) orbit with the period of approximately
2 yr is the shortest among the non-eclipsing RR Lyrae binary candidates. The
binary model gives a lowest estimate for the mass of the companion of 8.4
M_Sun, that places it among black hole candidates. Beside the first-overtone
pulsation, numerous additional non-radial pulsation frequencies were also
identified. We detected an ~47-d Blazhko-like irregular light-curve modulation.


title: An equivalence between Frobenius algebras and Calabi-Yau categories

abstract:
  We show that the bigroupoid of separable symmetric Frobenius algebras over an
algebraically closed field and the bigroupoid of finitely semi-simple
Calabi-Yau categories are equivalent. To this end, we construct a trace on the
category of finitely-generated representations of a symmetric, separable
Frobenius algebra, given by the composite of the Frobenius form with the
Hattori-Stallings trace. In order to put this result into perspective, we
introduce the concept of the equivariantization of a 2-functor between
bicategories endowed with a G-action. We prove that the equivalence between
Frobenius algebras and Calabi-Yau categories is actually the equivariantization
of the 2-functor sending a separable algebra to its category of
finitely-generated modules, where we endow both the bicategory of algebras,
bimodules and intertwiners and the bicategory of linear categories with the
trivial SO(2)-action and take homotopy fixed points as considered in [HSV16].


title: Normal State Properties of a resonantly interacting p-wave Fermi Gas

abstract:
  Motivated by the recent experimental progresses in the study of p-wave
resonant Fermi gas, we investigate the normal state properties of such a gas
close to a p-wave scattering resonance. We calculate the universal equation of
state and the two p-wave contacts which characterise the universal properties
of the system, in good agreement with experiments. Our calculation takes
explicit account of the effective range correction and obtains the superfluid
transition temperature $T_c$ within Nozi\`eres-Schmitt-Rink (NSR) scheme, and
shows that it lies within experimental reach. We derive analytic expression for
$T_c$ in the weak coupling limit and show explicitly the non-perturbative
nature of the effective range corrections.


title: First LHCb results from pA and Pb-Pb collisions

abstract:
  In 2015, the LHCb collaboration endorsed the proposal to pursue an ambitious
heavy-ion physics program. In 2013, LHCb has demonstrated its capabilities to
operate successfully in p-Pb and Pb-p collisions, leading already to several
important publications in the field. The measurements of the nuclear
modification factor and forward-backward production of prompt and displaced
J/$\psi$, $\psi$(2S) and $\Upsilon$(1S) states, as well as the production of
prompt $D^{0}$ mesons, have allowed to extend the knowledge of Cold Nuclear
Matter effects on open heavy flavours and quarkonium production. The
measurement of Z-boson production, important to constrain nuclear PDFs, and the
measurement of two-particle angular correlations, probing collective effects in
the dense environment of high energy collisions, have also been performed.
Furthermore, LHCb is the only experiment at the LHC that can be operated in
fixed-target mode, owing to the injection of a small amount of gas inside the
LHCb collision area. There have been several p-gas and Pb-gas data taking
periods during Run 1 and beginning of Run 2. This fixed target programme is
conducted at a center-of-mass energy of $\mathcal{O}$(100 GeV), and has great
potential to bridge the gap of knowledge between SPS and RHIC in the domain of
Quark Gluon Plasma physics. Finally, LHCb successfully participated to its
first Pb-Pb data taking at the end of 2015. First studies show that up to
semi-central Pb-Pb collisions can be successfully analysed to provide unique
measurements in the forward region. In this proceeding, we will present a
selection of LHCb results in pA collisions. We will also give some prospects
for fixed target and Pb-Pb studies.


title:
The monodromy theorem for compact K\"ahler manifolds and smooth
  quasi-projective varieties

abstract:
  Given any connected topological space $X$, assume that there exists an
epimorphism $\phi: \pi_1(X) \to \mathbb{Z}$. The deck transformation group
$\mathbb{Z}$ acts on the associated infinite cyclic cover $X^\phi$ of $X$,
hence on the homology group $H_i(X^\phi, \mathbb{C})$. This action induces a
linear automorphism on the torsion part of the homology group as a module over
the Laurent ring $\mathbb{C}[t,t^{-1}]$, which is a finite dimensional
$\mathbb{C}$-vector space. We study the sizes of the Jordan blocks of this
linear automorphism. When $X$ is a compact K\"ahler manifold, we show that all
the Jordan blocks are of size one. When $X$ is a smooth complex
quasi-projective variety, we give an upper bound on the sizes of the Jordan
blocks, which is an analogue of the Monodromy Theorem for the local Milnor
fibration.


title: Chatbots' Greetings to Human-Computer Communication

abstract:
  Both dialogue systems and chatbots aim at putting into action communication
between humans and computers. However, instead of focusing on sophisticated
techniques to perform natural language understanding, as the former usually do,
chatbots seek to mimic conversation. Since Eliza, the first chatbot ever,
developed in 1966, there were many interesting ideas explored by the chatbots'
community. Actually, more than just ideas, some chatbots' developers also
provide free resources, including tools and large-scale corpora. It is our
opinion that this know-how and materials should not be neglected, as they might
be put to use in the human-computer communication field (and some authors
already do it). Thus, in this paper we present a historical overview of the
chatbots' developments, we review what we consider to be the main contributions
of this community, and we point to some possible ways of coupling these with
current work in the human-computer communication research line.


title:
Network-regularized Sparse Logistic Regression Models for Clinical Risk
  Prediction and Biomarker Discovery

abstract:
  Molecular profiling data (e.g., gene expression) has been used for clinical
risk prediction and biomarker discovery. However, it is necessary to integrate
other prior knowledge like biological pathways or gene interaction networks to
improve the predictive ability and biological interpretability of biomarkers.
Here, we first introduce a general regularized Logistic Regression (LR)
framework with regularized term $\lambda \|\bm{w}\|_1 +
\eta\bm{w}^T\bm{M}\bm{w}$, which can reduce to different penalties, including
Lasso, elastic net, and network-regularized terms with different $\bm{M}$. This
framework can be easily solved in a unified manner by a cyclic coordinate
descent algorithm which can avoid inverse matrix operation and accelerate the
computing speed. However, if those estimated $\bm{w}_i$ and $\bm{w}_j$ have
opposite signs, then the traditional network-regularized penalty may not
perform well. To address it, we introduce a novel network-regularized sparse LR
model with a new penalty $\lambda \|\bm{w}\|_1 + \eta|\bm{w}|^T\bm{M}|\bm{w}|$
to consider the difference between the absolute values of the coefficients. And
we develop two efficient algorithms to solve it. Finally, we test our methods
and compare them with the related ones using simulated and real data to show
their efficiency.


title: Newforms of half-integral weight: the minus space counterpart

abstract:
  We define a subspace of the space of holomorphic modular forms of weight
$k+1/2$ and level $4M$ where $M$ is odd and square-free. We show that this
subspace is isomorphic under the Shimura-Niwa correspondence to the space of
newforms of weight $2k$ and level $2M$ and that this is a Hecke isomorphism.
The space we define is a proper subspace of the orthogonal complement of the
Kohnen plus space if the Kohnen plus space is nonzero.


title:
Dirac and Weyl Materials: Fundamental Aspects and Some Spintronics
  Applications

abstract:
  Dirac and Weyl materials refer to a class of solid materials which host
low-energy quasiparticle excitations that can be described by the Dirac and
Weyl equations in relativistic quantum mechanics. Starting with the advent of
graphene as the first prominent example, these materials have been attracting
tremendous interest owing to their novel fundamental properties as well as the
great potential for applications. Here we introduce the basic concepts and
notions related to Dirac and Weyl materials and briefly review some recent
works in this field, particularly on the conceptual development and the
possible spintronics/pseudospintronics applications.


title:
Finite speed heat transport in a quantum spin chain after quenched local
  cooling

abstract:
  We study the dynamics of an initially thermalized spin chain in the quantum
XY-model, after sudden coupling to a heat bath of lower temperature at one end
of the chain. In the semi-classical limit we see an exponential decay of the
system-bath heatflux by exact solution of the reduced dynamics. In the full
quantum description however, we numerically find the heatflux to reach
intermediate plateaus where it is approximately constant -- a phenomenon that
we attribute to the finite speed of heat transport via spin waves.


title:
Almost mixing of all orders and CLT for some $\mathbb{Z}^d$-actions on
  subgroups of $\mathbb{F}\_p^{\mathbb{Z}^d}$

abstract:
  For N d-actions by algebraic endomorphisms on compact abelian groups, the
existence of non-mixing configurations is related to "S-unit type" equations
and plays a role in limit theorems for such actions. We consider a family of
endomorphisms on shift-invariant subgroups of F Z d p and show that there are
few solutions of the corresponding equations. This implies the validity of the
Central Limit Theorem for different methods of summation.


title: Orbital edge states in a photonic honeycomb lattice

abstract:
  We experimentally reveal the emergence of edge states in a photonic lattice
with orbital bands. We use a two-dimensional honeycomb lattice of coupled
micropillars whose bulk spectrum shows four gapless bands arising from the
coupling of $p$-like photonic orbitals. We observe zero-energy edge states
whose topological origin is similar to that of conventional edge states in
graphene. Additionally, we report novel dispersive edge states that emerge not
only in zigzag and bearded terminations, but also in armchair edges. The
observations are reproduced by tight-binding and analytical calculations. Our
work shows the potentiality of coupled micropillars in elucidating some of the
electronic properties of emergent 2D materials with orbital bands.


title:
Regimes of strong electrostatic collapse of a highly charged
  polyelectrolyte in a poor solvent

abstract:
  We perform extensive molecular dynamics simulations of a highly charged
flexible polyelectrolyte (PE) chain in a poor solvent for the case when the
chain is in a collapsed state and the electrostatic interactions, characterized
by the reduced Bjerrum length $\ell_B$, are strong. We detect the existence of
several sub-regimes, $R_g \sim \ell_B^{-\gamma}$, in the dependence of the
gyration radius of the chain $R_g$ on $\ell_B$. In contrast to a good solvent,
the exponent $\gamma$ for a poor solvent crucially depends on the size and
valency of counterions. To explain the different sub-regimes we generalize the
existing counterion fluctuation theory by a more complete account of the volume
interactions in the free energy of the chain. These include interactions
between the chain monomers, between monomers and counterions and the
counterions themselves. We also demonstrate that the presence of the condensed
counterions can modify the effective attraction among the chain monomers and
impact the sign of the second virial coefficient.


title: Study of the reflection spectrum of the LMXB 4U 1702-429

abstract:
  The source 4U 1702-429 (Ara X-1) is a low-mass X-ray binary system hosting a
neutron star. Albeit the source is quite bright ( $\sim10^{37}$ erg s$^{-1}$)
its broadband spectrum has never been studied. Neither dips nor eclipses have
been observed in the light curve suggesting that its inclination angle is
smaller than 60$^{\circ}$.We analysed the broadband spectrum of 4U 1702-429 in
the 0.3-60 keV energy range, using XMM-Newton and INTEGRAL data, to constrain
its Compton reflection component if it is present. After excluding the three
time intervals in which three type-I X-ray bursts occurred, we fitted the joint
XMM-Newton and INTEGRAL spectra obtained from simultaneous observations. A
broad emission line at 6.7 keV and two absorption edges at 0.87 and 8.82 keV
were detected. We found that a self-consistent reflection model fits the 0.3-60
keV spectrum well. The broadband continuum is composed of an emission component
originating from the inner region of the accretion disc, a Comptonised direct
emission coming from a corona with an electron temperature of $2.63 \pm 0.06$
keV and an optical depth $\tau=13.6 \pm 0.2$, and, finally, a reflection
component. The best-fit indicates that the broad emission line and the
absorption edge at 8.82 keV, both associated with the presence of \ion{Fe}{xxv}
ions, are produced by reflection in the region above the disc with a ionisation
parameter of $Log(\xi) \simeq 2.7$. We have inferred that the inner radius,
where the broad emission line originates, is $64^{+52}_{-15}$ km, and the inner
radius of the accretion disc is $39^{+6}_{-8}$ km. (Abridged)


title:
Application of the MST clustering to the high energy gamma-ray sky. IV -
  Blazar candidates found as possible counterparts of photon clusters

abstract:
  We present the results of a cluster search in the Fermi-LAT Pass 8 gamma-ray
sky by means of the Minimum Spanning Tree algorithm, at energies higher than 10
GeV and at Galactic latitudes higher than 25 degrees. The selected clusters
have a minimum number of photons higher than or equal to 5, a high degree of
concentration, and are without a clear corresponding counterpart in blazar
catalogues. A sample of 30 possible gamma-ray sources was obtained. These
objects were verified by applying the standard Maximum Likelihood analysis on
the Fermi-LAT data. A search for possible radio counterparts in a circle having
a radius of 6 arcmin was performed, finding several interesting objects, the
majority of them without optical spectroscopical data. These can be considered
as new blazar candidates. Some of them were already noticed as possible blazars
or Active Galactic Nuclei in previous surveys, but never associated with high
energy emission. These possible counterparts are reported and their properties
are discussed.


title:
An application of the sum-product phenomenon to sets having no solutions
  of several linear equations

abstract:
  We prove that for an arbitrary $\kappa \le \frac{1}{3}$ any subset of
$\mathbf{F}_p$ avoiding $t$ linear equations with three variables has size less
than $O(p/t^\kappa)$. We also find several applications to problems about
so--called non--averaging sets, number of collinear triples and mixed energies.


title: One Sentence One Model for Neural Machine Translation

abstract:
  Neural machine translation (NMT) becomes a new state-of-the-art and achieves
promising translation results using a simple encoder-decoder neural network.
This neural network is trained once on the parallel corpus and the fixed
network is used to translate all the test sentences. We argue that the general
fixed network cannot best fit the specific test sentences. In this paper, we
propose the dynamic NMT which learns a general network as usual, and then
fine-tunes the network for each test sentence. The fine-tune work is done on a
small set of the bilingual training data that is obtained through similarity
search according to the test sentence. Extensive experiments demonstrate that
this method can significantly improve the translation performance, especially
when highly similar sentences are available.


title: Rare radiative leptonic B-decays

abstract:
  We obtain predictions for $B_{(s)}\to e^+e^-\gamma$ and $B_{(s)}\to
\mu^+\mu^-\gamma$ decays. All the contributions containing long-distance QCD
effects are calculated in the framework of relativistic quark model. The
contributions of the light vector-meson resonances related to the virtual
photon emission from valence quarks of the $B$-meson are included. The highest
branching ratios for the radiative leptonic B-decays are ${\cal B}(\bar
B^0_s\to e^+e^-\gamma)=18.8\times10^{-9}$ and ${\cal B}(B^0_s\to
\mu^+\mu^-\gamma)=12.2\times10^{-9}$. We also give the distribution of the
foward-backward asymmetry.


title: Document Image Coding and Clustering for Script Discrimination

abstract:
  The paper introduces a new method for discrimination of documents given in
different scripts. The document is mapped into a uniformly coded text of
numerical values. It is derived from the position of the letters in the text
line, based on their typographical characteristics. Each code is considered as
a gray level. Accordingly, the coded text determines a 1-D image, on which
texture analysis by run-length statistics and local binary pattern is
performed. It defines feature vectors representing the script content of the
document. A modified clustering approach employed on document feature vector
groups documents written in the same script. Experimentation performed on two
custom oriented databases of historical documents in old Cyrillic, angular and
round Glagolitic as well as Antiqua and Fraktur scripts demonstrates the
superiority of the proposed method with respect to well-known methods in the
state-of-the-art.


title: Computational experiments with nilpotent Lie algebra

abstract:
  In this note we present some experimental results on the general matrix
nilpotent Lie algebras derived by calculations on a computer


title:
Symbolic dynamics for non uniformly hyperbolic diffeomorphisms of
  compact smooth manifolds

abstract:
  We construct countable Markov partitions for non-uniformly hyperbolic
diffeomorphisms on compact manifolds of any dimension, extending earlier work
of O. Sarig for surfaces. These partitions allow us to obtain symbolic coding
on invariant sets of full measure for all hyperbolic measures whose Lyapunov
exponents are bounded away from zero by a constant. Applications include
counting results for hyperbolic periodic orbits, and structure of hyperbolic
measures of maximal entropy.


title: New fermions in the bulk

abstract:
  Spinor fields on 5-dimensional Lorentzian manifolds are classified, according
to the geometric Fierz identities that involve their bilinear covariants. Based
upon this classification that generalises the celebrated 4-dimensional Lounesto
classification of spinor fields, new non-trivial classes of 5-dimensional
spinor fields are, hence, found, with important potential applications
regarding bulk fermions and their subsequent localisation on brane-worlds. In
addition, quaternionic bilinear covariants are used to derive the quaternionic
spin density, through the truncated exterior bundle. In order to accomplish a
realisation of these new spinors, a Killing vector field is constructed on the
horizon of 5-dimensional Kerr black holes. This Killing vector field is shown
to reach the time-like Killing vector field at the spatial infinity, through a
current 1-form density, constructed with the derived new spinor fields. The
current density is, moreover, expressed as the f\"unfbein components, assuming
a condensed form.


title:
Initial Temperature and Extent of Chemical Equilibration of Partons in
  Relativistic Collision of Heavy Nuclei

abstract:
  We emphasize that a knowledge of energy and entropy densities of quark gluon
plasma - a thermalized de-confined matter, formed in relativistic heavy ion
collisions fixes the formation temperature and the product of gluon fugacity
and formation time uniquely, {\em provided} we know the relative fugacities of
quarks and gluons. This also provides that a smaller formation time would imply
larger fugacities for partons. Next we explore the limits of chemical
equilibration of partons during the initial stages in relativistic collision of
heavy nuclei. The experimentally measured rapidity densities of transverse
energy and charged particle multiplicity at RHIC and LHC energies are used to
estimate the energy and number densities with the assumption of formation of a
thermally equilibrated quark gluon plasma which may be chemically equilibrated
to the same or differing extents for quarks and gluons. The estimates are found
to be very sensitive to the correction factor used for the Bj\"{o}rken energy
density for identifying it with the initial energy density. The extent of
chemical equilibration near the end of the QGP phase is inferred by solving
master equations by including the processes $gg \leftrightarrow ggg$ and $gg
\leftrightarrow q\overline{q}$ along with expansion and cooling of the plasma.
The possible consequences for invariant mass distribution of intermediate mass
dileptons radiated from the plasma are discussed which could distinguish
between different scenarios.


title: On the asymptotic prime partitions of integers

abstract:
  In this paper, we discuss P(n), the number of ways in which a given integer n
may be written as a sum of primes. In particular, an asymptotic form P_as(n)
valid for n towards infinity is obtained analytically using standard techniques
of quantum statistical mechanics. First, the bosonic partition function of
primes, or the generating function of unrestricted prime partitions in number
theory, is constructed. Next, the density of states is obtained using the
saddle-point method for Laplace inversion of the partition function in the
limit of large n. This directly gives the asymptotic number of prime partitions
P_as(n). The leading term in the asymptotic expression grows exponentially as
sqrt[n/ln(n)] and agrees with previous estimates. We calculate the
next-to-leading order term in the exponent, porportional to ln[ln(n)]/ln(n),
and show that an earlier result in the literature for its coefficient is
incorrect. Furthermore, we also calculate the next higher order correction,
proportional to 1/ln(n) and given in Eq.(43), which so far has not been
available in the literature. Finally, we compare our analytical results with
the exact numerical values of P(n) up to n \sim 8 10^6. For the highest values,
the remaining error between the exact P(n) and our P_as(n) is only about half
of that obtained with the leading-order (LO) approximation. But we also show
that, unlike for other types of partitions, the asymptotic limit for the prime
partitions is still quite far from being reached even for n \sim 10^7.


title:
The porous medium equation with large initial data on negatively curved
  Riemannian manifolds

abstract:
  We show existence and uniqueness of very weak solutions of the Cauchy problem
for the porous medium equation on Cartan-Hadamard manifolds satisfying suitable
lower bounds on Ricci curvature, with initial data that can grow at infinity at
a prescribed rate, that depends crucially on the curvature bounds. The
curvature conditions we require are sharp for uniqueness in the sense that if
they are not satisfied then, in general, there can be infinitely many solutions
of the Cauchy problem even for bounded data. Furthermore, under matching upper
bounds on sectional curvatures, we give a precise estimate for the maximal
existence time, and we show that in general solutions do not exist if the
initial data grow at infinity too fast. This proves in particular that the
growth rate of the data we consider is optimal for existence. Pointwise blow-up
is also shown for a particular class of manifolds and of initial data.


title:
Towards a global scientific brain: Indicators of researcher mobility
  using co-affiliation data

abstract:
  This paper analyses the potential use of bibliometric data for mapping and
applying network analysis to mobility flows. We show case mobility networks at
three different levels of aggregation: at the country level, at the city level
and at the institutional level. We reflect on the potential uses of
bibliometric data to inform research policies with regard to scientific
mobility.


title: Wavelet-Based Segmentation on the Sphere

abstract:
  Segmentation, a useful/powerful technique in pattern recognition, is the
process of identifying object outlines within images. There are a number of
efficient algorithms for segmentation in Euclidean space that depend on the
variational approach and partial differential equation modelling. Wavelets have
been used successfully in various problems in image processing, including
segmentation, inpainting, noise removal, super-resolution image restoration,
and many others. Wavelets on the sphere have been developed to solve such
problems for data defined on the sphere, which arise in numerous fields such as
cosmology and geophysics. In this work, we propose a wavelet-based method to
segment images on the sphere, accounting for the underlying geometry of
spherical data. Our method is a direct extension of the tight-frame based
segmentation method used to automatically identify tube-like structures such as
blood vessels in medical imaging. It is compatible with any arbitrary type of
wavelet frame defined on the sphere, such as axisymmetric wavelets, directional
wavelets, curvelets, and hybrid wavelet constructions. Such an approach allows
the desirable properties of wavelets to be naturally inherited in the
segmentation process. In particular, directional wavelets and curvelets, which
were designed to efficiently capture directional signal content, provide
additional advantages in segmenting images containing prominent directional and
curvilinear features. We present several numerical experiments, applying our
wavelet-based segmentation method, as well as the common K-means method, on
real-world spherical images. These experiments demonstrate the superiority of
our method and show that it is capable of segmenting different kinds of
spherical images, including those with prominent directional features.
Moreover, our algorithm is efficient with convergence usually within a few
iterations.


title:
Concentration-compactness principle for nonlocal scalar field equations
  with critical growth

abstract:
  The aim of this paper is to study a concentration-compactness principle for
homogeneous fractional Sobolev space $\mathcal{D}^{s,2} (\mathbb{R}^N)$ for
$0<s<\min\{1,N/2\}.$ As an application we establish Palais-Smale compactness
for the Lagrangian associated to the fractional scalar field equation
$(-\Delta)^{s} u = f(x,u)$ for $0<s<1.$ Moreover, using an analytic framework
based on $\mathcal{D}^{s,2}(\mathbb{R}^N),$ we obtain the existence of ground
state solutions for a wide class of nonlinearities in the critical growth
range.


title: Dissecting new physics models through kinematic edges

abstract:
  Kinematic edges in the invariant mass distributions of different final state
particles are typically a signal of new physics. In this work we propose a
scenario wherein these edges could be utilised in discriminating between
different classes of models. To this effect, we consider the resonant
production of a heavy Higgs like resonance (H 1 ) as a case study. Such states
are a characteristic feature of many new physics scenarios beyond the Standard
Model (SM). In the event of a discovery, it is essential to identify the true
nature of the underlying theory. In this work we propose a channel, $H_1
\rightarrow t_2 t$, where t_2 is a vector-like gauge singlet top-partner that
decays into W b, Zt, ht. Invariant mass distributions constructed out of these
final states are characterized by the presence of kinematic edges, which are
unique to the topology under consideration. Further, since all the final state
particles are SM states, the position in the edges of these invariant mass
distributions can be used to exclusively determine the masses of the
resonances. Observation of these features are meant to serve as a trigger,
thereby mandating a more detailed analysis in a particular direction of
parameter space. The absence of these edge like features, in the specific
invariant mass distributions considered here, in minimal versions of
supersymmetric models (MSSM) also serves as a harbinger of such non MSSM-like
scenarios.


title:
Analysis of the cool down related cavity performance of the European
  XFEL vertical acceptance tests

abstract:
  It has been reported that the cool down dynamics across $T_c$ has a
significant influence on the observed quality factors $Q_0$ of a cavity, which
is most likely due to trapped flux. In this document we show the results of the
investigation if such a correlation can be observed during the European XFEL
cavity production.


title:
Brillouin-Wigner Theory for Floquet Topological Phase Transitions in
  Spin-orbit Coupled Materials

abstract:
  We develop the high frequency expansion based on the Brillouin-Wigner (B-W)
perturbation theory for driven systems with spin-orbit coupling which is
applicable to the cases of silicene, germanene and stanene. We compute the
effective Hamiltonian in the zero photon subspace not only to order
$O(\omega^{-1})$, but by keeping all the important terms to order
$O(\omega^{-2})$, and obtain the photo-assisted correction terms to both the
hopping and the spin-orbit terms, as well as new longer ranged hopping terms.
We then use the effective static Hamiltonian to compute the phase diagram in
the high frequency limit and compare it with the results of direct numerical
computation of the Chern numbers of the Floquet bands, and show that at
sufficiently large frequencies, the B-W theory high frequency expansion works
well even in the presence of spin-orbit coupling terms.


title: Li-rich AGB/RGB stars: Lithium abundances and mass loss

abstract:
  Most metal-rich AGB/RGB stars present strong Li underabundances, since this
element is easily destroyed in the high temperatures of the stellar interiors.
In spite of this fact, several of these stars are Li-rich, having Li abundances
given by log (Li/H) + 12 > 1.5. In the present work, we extend our previous
investigation on AGB/RGB stars to the expected mass loss rates of these stars.
Specifically, we look for correlations between the Li abundances and the mass
loss rates or related parameters in Li-rich AGB/RGB stars. We have estimated
the mass loss rates using a modified form of the Reimers formula and applied it
to a large sample of 104 Li-rich giant stars for which reliable stellar data
are available. Our proposed method assumes a linear relation between the
stellar luminosity and the Li abundance, so that the luminosity can be
estimated from the Li abundance. The stellar mass is then obtained from the
effective temperature and luminosity using recent evolutionary tracks. The
stellar radius can be determined from the stellar gravity, so that the mass
loss rate can be calculated using an adequate calibration involving both
Li-rich and Li-poor stars in the AGB/RGB branches. The results show that most
Li-rich stars have lower mass loss rates compared with C-rich or O-rich giants
that do not present Li enhancements.


title:
Unconditionally saturated Banach space with the scalar-plus-compact
  property

abstract:
  We construct a Bourgain-Delbaen $\mathscr{L}_\infty$-space
$\mathfrak{X}_{Kus}$ with strongly heterogenous structure: any bounded operator
on $\mathfrak{X}_{Kus}$ is a compact perturbation of a multiple of the
identity, whereas the space $\mathfrak{X}_{Kus}$ is saturated with
unconditional basic sequences.


title:
Number of Eigenvalues of Non-self-adjoint Schr\"{o}dinger Operators with
  Dilation Analytic Complex Potentials

abstract:
  In this paper, we give Lieb-Thirring type inequalities for isolated
eigenvalues of $d$-dimensional non-selfadjoint Schr\"{o}dinger operators with
complex-valued and dilation analytic potentials. In order to derive them, we
prove that isolated eigenvalues and their multiplicities are invariant under
complex dilation.


title: Global Versus Local Computations: Fast Computing with Identifiers

abstract:
  This paper studies what can be computed by using probabilistic local
interactions with agents with a very restricted power in polylogarithmic
parallel time. It is known that if agents are only finite state (corresponding
to the Population Protocol model by Angluin et al.), then only semilinear
predicates over the global input can be computed. In fact, if the population
starts with a unique leader, these predicates can even be computed in a
polylogarithmic parallel time. If identifiers are added (corresponding to the
Community Protocol model by Guerraoui and Ruppert), then more global predicates
over the input multiset can be computed. Local predicates over the input sorted
according to the identifiers can also be computed, as long as the identifiers
are ordered. The time of some of those predicates might require exponential
parallel time. In this paper, we consider what can be computed with Community
Protocol in a polylogarithmic number of parallel interactions. We introduce the
class CPPL corresponding to protocols that use $O(n\log^k n)$, for some k,
expected interactions to compute their predicates, or equivalently a
polylogarithmic number of parallel expected interactions. We provide some
computable protocols, some boundaries of the class, using the fact that the
population can compute its size. We also prove two impossibility results
providing some arguments showing that local computations are no longer easy:
the population does not have the time to compare a linear number of consecutive
identifiers. The Linearly Local languages, such that the rational language
$(ab)^*$, are not computable.


title: An Indecomposable and unconditionally saturated Banach space

abstract:
  We construct an indecomposable reflexive Banach space $X_{ius}$ such that
every infinite dimensional closed subspace contains an unconditional basic
sequence. We also show that every operator $T\in \mathcal{B}(X_{ius})$ is of
the form $\lambda I+S$ with $S$ a strictly singular operator.


title: $X_\text{max}$ reconstruction from amplitude information with AERA

abstract:
  The standard method to estimate the mass of a cosmic ray is the measurement
of the atmospheric depth of the shower maximum ($X_\text{max}$). This depth is
strongly correlated with the mass of the primary because it depends on the
interaction cross section of the primary with the constituents of the
atmosphere. Measuring the electric field, emitted by the secondary particles of
an extensive air shower (EAS), with the Auger Engineering Radio Array (AERA) in
the 30-80 MHz band allows the determination of the depth of shower maximum on
the basis of the good understanding of the radio emission mechanisms. The duty
cycle of radio detectors is close to 100\%, making possible the statistical
determination of the cosmic-ray mass composition through the study of a large
number of cosmic rays above 10$^{17}$ eV. In this contribution, $X_\text{max}$
reconstruction methods based on the study of the radio signal with AERA are
detailed.


title: SIS epidemics on Triadic Random Graphs

abstract:
  It has been shown in the past that many real-world networks exhibit community
structures and non-trivial clustering which comes with the occurrence of a
notable number of triangular connections. Yet the influence of such connection
patterns on the dynamics of disease transmission is not fully understood. In
order to study their role in the context of Susceptible-Infected-Susceptible
(SIS) epidemics we use the Triadic Random Graph (TRG) model to construct small
networks (N=49) from distinct, closed, directed triadic subpatterns. We compare
various global properties of TRGs and use the N-intertwined mean-field
approximation (NIMFA) model to perform numerical simulations of SIS-dynamics on
TRGs. The results show that the infection spread on undirected TRGs displays
very similar behavior to TRGs with an abundance of (directed) feed-back-loops,
while using (directed) feed-forward-loops as network-entities significantly
slows down the epidemic and lowers the number of infected individuals in the
endemic state. Moreover, we introduce a novel stochastic approach for modelling
the SIS-epidemics on TRGs based on characterizing nodes according to their set
of $\left(k_{in},k_{out}\right)$ within triads. Within this model, the topology
of the network is given by the number and the local structure of directed
triadic motifs and not by the adjacency matrix. Nevertheless, the outcome of
simulations is qualitatively similar to the results of the NIMFA model.


title:
Further analysis of the budgets of the dissipation tensor
  $\varepsilon_{ij}$ in turbulent plane channel flow

abstract:
  Recent DNS results [Gerolymos G.A., Vallet I. : J. Fluid Mech. 807 (2016)
386--418] have provided data for the terms in the transport equations for the
components of the dissipation tensor $\varepsilon_{ij}$ in low-Reynolds
turbulent plane channel flow. The present paper extends the previous results by
a detailed analysis of the behaviour of various mechanisms in the
$\varepsilon_{ij}$-transport equations (production, diffusion, redistribution,
destruction), with particular emphasis on the component-by-component comparison
with the corresponding mechanisms in the transport equations for the
Reynolds-stresses $r_{ij}$. The splitting of the pressure terms for the
wall-normal components into redistribution and pressure-diffusion reveals
substantially different behaviour near the wall. The wall-asymptotics of
different terms in the transport equations are studied in detail, and examined
using the DNS data. Both DNS data and wall-asympotic analysis show that the
anisotropy of the destruction-of-dissipation tensor
$\varepsilon_{\varepsilon_{ij}}$ is fundamentally different from that of
$r_{ij}$ or $\varepsilon_{ij}$, never approaching the 2-component (2-C) state
at the solid wall.


title: Model Checking Spatial Logics for Closure Spaces

abstract:
  Spatial aspects of computation are becoming increasingly relevant in Computer
Science, especially in the field of collective adaptive systems and when
dealing with systems distributed in physical space. Traditional formal
verification techniques are well suited to analyse the temporal evolution of
programs; however, properties of space are typically not taken into account
explicitly. We present a topology-based approach to formal verification of
spatial properties depending upon physical space. We define an appropriate
logic, stemming from the tradition of topological interpretations of modal
logics, dating back to earlier logicians such as Tarski, where modalities
describe neighbourhood. We lift the topological definitions to the more general
setting of closure spaces, also encompassing discrete, graph-based structures.
We extend the framework with a spatial surrounded operator, a propagation
operator and with some collective operators. The latter are interpreted over
arbitrary sets of points instead of individual points in space. We define
efficient model checking procedures, both for the individual and the collective
spatial fragments of the logic and provide a proof-of-concept tool.


title: Streamwise decay of localized states in channel flow

abstract:
  Channel flow, the pressure driven flow between parallel plates, has exact
coherent structures that show various degrees of localization. For states which
are localized in streamwise direction but extended in spanwise direction, we
show that they are exponentially localized, with decay constants that are
different on the upstream and downstream side. We extend the analysis of Brand
and Gibson [J. Fluid Mech. 750, R1 (2014)] for stationary states to the case of
advected structures that is needed here, and derive expressions for the decay
in terms of eigenvalues and eigenfunctions of certain second order differential
equations. The results are in very good agreement with observations on exact
coherent structures of different transversal wave lengths.


title: The Complexity of the Numerical Semigroup Gap Counting Problem

abstract:
  In this paper, we prove that the numerical-semigroup-gap counting problem is
#NP-complete as a main theorem. A numerical semigroup is an additive semigroup
over the set of all nonnegative integers. A gap of a numerical semigroup is
defined as a positive integer that does not belong to the numerical semigroup.
The computation of gaps of numerical semigroups has been actively studied from
the 19th century. However, little has been known on the computational
complexity. In 2005, Ramirez-Alfonsin proposed a question whether or not the
numerical-semigroup-gap counting problem is #P-complete. This work is an answer
for his question. For proving the main theorem, we show the #NP-completenesses
of other two variants of the numerical-semigroup-gap counting problem.


title:
Decoupled Uplink and Downlink in a Wireless System with Buffer-Aided
  Relaying

abstract:
  The paper treats a multiuser relay scenario where multiple user equipments
(UEs) have a two-way communication with a common Base Station (BS) in the
presence of a buffer-equipped Relay Station (RS). Each of the uplink (UL) and
downlink (DL) transmission can take place over a direct or over a relayed path.
Traditionally, the UL and the DL path of a given two-way link are coupled, that
is, either both are direct links or both are relayed links. By removing the
restriction for coupling, one opens the design space for a decoupled two-way
links. Following this, we devise two protocols: orthogonal decoupled UL/DL
buffer-aided (ODBA) relaying protocol and non-orthogonal decoupled UL/DL
buffer-aided (NODBA) relaying protocol. In NODBA, the receiver can use
successive interference cancellation (SIC) to extract the desired signal from a
collision between UL and DL signals. For both protocols, we characterize the
transmission decision policies in terms of maximization of the average two-way
sum rate of the system. The numerical results show that decoupling association
and non-orthogonal radio access lead to significant throughput gains for
two-way traffic.


title: Force sensitivity of multilayer graphene optomechanical devices

abstract:
  Mechanical resonators based on low-dimensional materials are promising for
force and mass sensing experiments. The force sensitivity in these ultra-light
resonators is often limited by the imprecision in the measurement of the
vibrations, the fluctuations of the mechanical resonant frequency, and the
heating induced by the measurement. Here, we strongly couple multilayer
graphene resonators to superconducting cavities in order to achieve a
displacement sensitivity of $1.3$ fm Hz$^{-1/2}$. This coupling also allows us
to damp the resonator to an average phonon occupation of $7.2$. Our best force
sensitivity, $390$ zN Hz$^{-1/2}$ with a bandwidth of $200$ Hz, is achieved by
balancing measurement imprecision, optomechanical damping, and heating. Our
results hold promise for studying the quantum capacitance of graphene, its
magnetization, and the electron and nuclear spins of molecules adsorbed on its
surface.


title: A note on discrete Borg-type theorems

abstract:
  We consider the discrete versions of the well known Borg theorem and use
simple linear algebraic techniques to obtain new versions of the discrete Borg
type theorems. To be precise, we prove that the periodic potential of a
discrete Schrodinger operator is almost a constant if and only if the possible
spectral gaps of the operator are of small width. This result is further
extended to more general settings and the connection to the well known Ten
Martini problem is also discussed.


title: Thermal conductance of Nb thin films at sub-kelvin temperatures

abstract:
  We determine the thermal conductance of thin niobium (Nb) wires on a silica
substrate in the temperature range of 0.1 - 0.6 K using electron thermometry
based on normal metal-insulator-superconductor tunnel junctions. We find that
at 0.6 K, the thermal conductance of Nb is two orders of magnitude lower than
that of Al in the superconducting state, and two orders of magnitude below the
Wiedemann-Franz conductance calculated with the normal state resistance of the
wire. The measured thermal conductance exceeds the prediction of the
Bardeen-Cooper-Schrieffer theory, and demonstrates a power law dependence on
temperature as $T^{4.5}$, instead of an exponential one. At the same time, we
monitor the temperature profile of the substrate along the Nb wire to observe
possible overheating of the phonon bath. We show that Nb can be successfully
used for thermal insulation in a nanoscale circuit while simultaneously
providing an electrical connection.


title:
Don't Be Greedy: Leveraging Community Structure to Find High Quality
  Seed Sets for Influence Maximization

abstract:
  We consider the problem of maximizing the spread of influence in a social
network by choosing a fixed number of initial seeds --- a central problem in
the study of network cascades. The majority of existing work on this problem,
formally referred to as the influence maximization problem, is designed for
submodular cascades. Despite the empirical evidence that many cascades are
non-submodular, little work has been done focusing on non-submodular influence
maximization.
  We propose a new heuristic for solving the influence maximization problem and
show via simulations on real-world and synthetic networks that our algorithm
outputs more influential seed sets than the state-of-the-art greedy algorithm
in many natural cases, with average improvements of 7% for submodular cascades,
and 55% for non-submodular cascades. Our heuristic uses a dynamic programming
approach on a hierarchical decomposition of the social network to leverage the
relation between the spread of cascades and the community structure of social
networks. We verify the importance of network structure by showing the quality
of the hierarchical decomposition impacts the quality of seed set output by our
algorithm. We also present "worst-case" theoretical results proving that in
certain settings our algorithm outputs seed sets that are a factor of
$\Theta(\sqrt{n})$ more influential than those of the greedy algorithm, where
$n$ is the number of nodes in the network. Finally, we generalize our algorithm
to a message passing version that can be used to find seed sets that have at
least as much influence as the dynamic programming algorithms.


title: Spin Hall magnetoresistance in antiferromagnet/normal metal bilayers

abstract:
  We predict the emergence of spin Hall magnetoresistance in a magnetic bilayer
composed of a normal metal adjacent to an antiferromagnet. Based on a recently
derived drift-diffusion equation, we show that the resistance of the bilayer
depends on the relative angle between the direction transverse to the current
flow and the N\'eel order parameter. Although this effect presents striking
similarities with the spin Hall magnetoresistance recently reported in
ferromagnetic bilayers, in the present case its physical origin is attributed
to the anisotropic spin relaxation of itinerant spins in the antiferromagnet.


title: Computing Vertex-Disjoint Paths using MAOs

abstract:
  Let G be a graph with minimum degree $\delta$. It is well-known that maximal
adjacency orderings (MAOs) compute a vertex set S such that every pair of S is
connected by at least $\delta$ internally vertex-disjoint paths in G.
  We present an algorithm that, given any pair of S, computes these $\delta$
paths in linear time O(n+m). This improves the previously best solutions for
these special vertex pairs, which were flow-based. Our algorithm simplifies a
proof about pendant pairs of Mader and makes a purely existential proof of
Nagamochi algorithmic.


title:
Hollow carbon sphere/metal oxide nanocomposite anodes for lithium-ion
  batteries

abstract:
  Hollow carbon spheres (HCS) covered with metal oxide nanoparticles (SnO2 and
MnO2, respectively) were successfully synthesized and investigated regarding
their potential as anode materials for lithium-ion batteries. Raman
spectroscopy shows a high degree of graphitization for the HCS host structure.
The mesoporous nature of the nanocomposites is confirmed by
Brunauer-Emmett-Teller analysis. For both metal oxides under study, the metal
oxide functionalization of HCS yields a significant increase of electrochemical
performance. The charge capacity of HCS/SnO2 is 370 mAh/g after 45 cycles (266
mAh/g in HCS/MnO2) which clearly exceeds the value of 188 mAh/g in pristine
HCS. Remarkably, the data imply excellent long term cycling stability after 100
cycles in both cases. The results hence show that mesoporous HCS/metal oxide
nanocomposites enable exploiting the potential of metal oxide anode materials
in Lithium-ion batteries by providing a HCS host structure which is both
conductive and stable enough to accommodate big volume change effects.


title:
Fingerprints of different interaction mechanisms on the collective modes
  in complex (dusty) plasmas

abstract:
  In this paper we discuss the relations between the exact shape of
interparticle interactions in complex (dusty) plasmas and the dispersion
relation of the longitudinal collective mode. Several representative repulsive
potentials, predicted previously theoretically, are chosen and the
corresponding dispersion relations are calculated using the quasi-crystalline
approximation. Both weakly coupled and strongly coupled regimes are considered.
It is shown that the long-wavelength portions of the dispersion relations are
sensitive to the long-range asymptote of the interaction potential. This can be
used to discriminate between different interaction mechanisms operational in
complex plasmas experimentally. Main requirements are briefly discussed.


title: Detailed study of a transverse field Zeeman slower

abstract:
  We present a thorough analysis of a Zeeman slower for sodium atoms made of
permanent magnets in a Halbach configuration. Due to the orientation of the
magnetic field, the polarisation of the slowing laser beam cannot be purely
circular leading to optical leakages into dark states. To circumvent this
effect, we propose an atomic state preparation stage able to significantly
increase the performances of the Zeeman slower. After a careful theoretical
analysis of the problem, we experimentally implement an optical pumping stage
leading to an increase of the magneto-optical trap loading rate by 3.5. Such
method is easy to set up and could be extended to other Zeeman slower
architectures.


title: Temporal Data Exchange

abstract:
  Data exchange is the problem of transforming data that is structured under a
source schema into data structured under another schema, called the target
schema, so that both the source and target data satisfy the relationship
between the schemas. Even though the formal framework of data exchange for
relational database systems is well-established, it does not immediately carry
over to the settings of temporal data, which necessitates reasoning over
unbounded periods of time. In this work, we study data exchange for temporal
data. We first motivate the need for two views of temporal data: the concrete
view, which depicts how temporal data is compactly represented and on which the
implementations are based, and the abstract view, which defines the semantics
of temporal data as a sequence of snapshots. We first extend the chase
procedure for the abstract view to have a conceptual basis for the data
exchange for temporal databases. Considering non-temporal source-to-target
tuple generating dependencies and equality generating dependencies, the chase
algorithm can be applied on each snapshot independently. Then we define a chase
procedure (called c-chase) on concrete instances and show the result of c-chase
on a concrete instance is semantically aligned with the result of chase on the
corresponding abstract instance. In order to interpret intervals as constants
while checking if a dependency or a query is satisfied by a concrete database,
we will normalize the instance with respect to the dependency or the query. To
obtain the semantic alignment, the nulls in the concrete view are annotated
with temporal information. Furthermore, we show that the result of the concrete
chase provides a foundation for query answering. We define naive evaluation on
the result of the c-chase and show it produces certain answers.


title: Resonances for Symmetric Tensors on Asymptotically Hyperbolic Spaces

abstract:
  On manifolds with an even Riemannian conformally compact Einstein metric, the
resolvent of the Lichnerowicz Laplacian, acting on trace-free, divergence-free,
symmetric 2-tensors is shown to have a meromorphic continuation to the complex
plane, defining quantum resonances of this Laplacian. For higher rank symmetric
tensors, a similar result is proven for (convex cocompact) quotients of
hyperbolic space.


title: Quantum model for mode locking in pulsed semiconductor quantum dots

abstract:
  Quantum dots in GaAs/InGaAs structures have been proposed as a candidate
system for realizing quantum computing. The short coherence time of the
electronic quantum state that arises from coupling to the nuclei of the
substrate is dramatically increased if the system is subjected to a magnetic
field and to repeated optical pulsing. This enhancement is due to mode locking:
Oscillation frequencies resonant with the pulsing frequencies are enhanced,
while off-resonant oscillations eventually die out. Because the resonant
frequencies are determined by the pulsing frequency only, the system becomes
immune to frequency shifts caused by the nuclear coupling and by slight
variations between individual quantum dots. The effects remain even after the
optical pulsing is terminated. In this work, we explore the phenomenon of mode
locking from a quantum mechanical perspective. We treat the dynamics using the
central spin model, which includes coupling to 10-20 nuclei and incoherent
decay of the excited electronic state, in a perturbative framework. Using
scaling arguments, we extrapolate our results to realistic system parameters.
We find that the synchronization to the pulsing frequency needs time scales in
the order of 1 s.


title: Unstoppable brane-flux decay of $\overline{\text{D6}}$ branes

abstract:
  We investigate $p$ $\overline{\text{D6}}$ branes inside a flux throat that
carries $K \times M$ D6 charges with $K$ the 3-form flux quantum and $M$ the
Romans mass. We find that within the calculable supergravity regime where $g_s
p$ is large, the $\overline{\text{D6}}$ branes annihilate immediately against
the fluxes despite the existence of a metastable state at small $p/M$ in the
probe approximation. The crucial property that causes this naive conflict with
effective field theory is a singularity in the 3-form flux, which we cut off at
string scale. Our result explains the absence of regular solutions at finite
temperature and suggests there should be a smooth time-dependent solution. We
also discuss the qualitative differences between $\overline{\text{D6}}$ branes
and $\overline{\text{D3}}$ branes, which makes it a priori not obvious to
conclude the same instability for $\overline{\text{D3}}$ branes.


title:
Weakly supervised spoken term discovery using cross-lingual side
  information

abstract:
  Recent work on unsupervised term discovery (UTD) aims to identify and cluster
repeated word-like units from audio alone. These systems are promising for some
very low-resource languages where transcribed audio is unavailable, or where no
written form of the language exists. However, in some cases it may still be
feasible (e.g., through crowdsourcing) to obtain (possibly noisy) text
translations of the audio. If so, this information could be used as a source of
side information to improve UTD. Here, we present a simple method for rescoring
the output of a UTD system using text translations, and test it on a corpus of
Spanish audio with English translations. We show that it greatly improves the
average precision of the results over a wide range of system configurations and
data preprocessing methods.


title: On the expansions of real numbers in two multiplicative dependent bases

abstract:
  Let $r \ge 2$ and $s \ge 2$ be multiplicatively dependent integers. We
establish a lower bound for the sum of the block complexities of the $r$-ary
expansion and of the $s$-ary expansion of an irrational real number, viewed as
infinite words on $\{0, 1, \ldots , r-1\}$ and $\{0, 1, \ldots , s-1\}$, and we
show that this bound is best possible.


title:
Bibliographic Analysis on Research Publications using Authors,
  Categorical Labels and the Citation Network

abstract:
  Bibliographic analysis considers the author's research areas, the citation
network and the paper content among other things. In this paper, we combine
these three in a topic model that produces a bibliographic model of authors,
topics and documents, using a nonparametric extension of a combination of the
Poisson mixed-topic link model and the author-topic model. This gives rise to
the Citation Network Topic Model (CNTM). We propose a novel and efficient
inference algorithm for the CNTM to explore subsets of research publications
from CiteSeerX. The publication datasets are organised into three corpora,
totalling to about 168k publications with about 62k authors. The queried
datasets are made available online. In three publicly available corpora in
addition to the queried datasets, our proposed model demonstrates an improved
performance in both model fitting and document clustering, compared to several
baselines. Moreover, our model allows extraction of additional useful knowledge
from the corpora, such as the visualisation of the author-topics network.
Additionally, we propose a simple method to incorporate supervision into topic
modelling to achieve further improvement on the clustering task.


title:
On Data-Independent Properties for Density-Based Dissimilarity Measures
  in Hybrid Clustering

abstract:
  Hybrid clustering combines partitional and hierarchical clustering for
computational effectiveness and versatility in cluster shape. In such
clustering, a dissimilarity measure plays a crucial role in the hierarchical
merging. The dissimilarity measure has great impact on the final clustering,
and data-independent properties are needed to choose the right dissimilarity
measure for the problem at hand. Properties for distance-based dissimilarity
measures have been studied for decades, but properties for density-based
dissimilarity measures have so far received little attention. Here, we propose
six data-independent properties to evaluate density-based dissimilarity
measures associated with hybrid clustering, regarding equality, orthogonality,
symmetry, outlier and noise observations, and light-tailed models for
heavy-tailed clusters. The significance of the properties is investigated, and
we study some well-known dissimilarity measures based on Shannon entropy,
misclassification rate, Bhattacharyya distance and Kullback-Leibler divergence
with respect to the proposed properties. As none of them satisfy all the
proposed properties, we introduce a new dissimilarity measure based on the
Kullback-Leibler information and show that it satisfies all proposed
properties. The effect of the proposed properties is also illustrated on
several real and simulated data sets.


title: BITLLES: Electron Transport Simulation with Quantum Trajectories

abstract:
  After the seminal work of R. Landauer in 1957 relating the electrical
resistance of a conductor to its scattering properties, much progress has been
made in our ability to predict the performance of electron devices in the DC
(stationary) regime. Computational tools to describe their dynamical behavior
(including the AC, transient and noise performance), however, are far from
being as trustworthy as would be desired by the electronic industry. While
there is no fundamental limitation to correctly modeling the high-frequency
quantum transport and its fluctuations, certainly more careful attention must
be paid to delicate issues such as overall charge neutrality, total current
conservation, or the back action of the measuring apparatus. In this review, we
will show how the core ideas behind the Bohmian formulation of quantum
mechanics can be exploited to design an efficient Monte Carlo algorithm that
provides a quantitative description of electron transport in open quantum
systems. By making the most of trajectory-based and wave function methods, the
BITLLES simulator, a free software developed by the authors, extends the
capabilities that the semi-classical Monte Carlo simulation technique has
offered for decades (DC, AC, noise, transients) to the quantum regime.


title: Holographic phase transition probed by non-local observables

abstract:
  From the viewpoint of holography, the phase structure of a 5-dimensional
Reissner-Nordstr\"{o}m-AdS black hole is probed by the two point correlation
function, Wilson loop, and entanglement entropy. As the case of thermal
entropy, we find for all the probes, the black hole undergos a Hawking-Page
phase transition, a first order phase transition and a second order phase
transition successively before it reaches to a stable phase. In addition, for
these probes, we find the equal area law for the first order phase transition
is valid always and the critical exponent of the heat capacity for the second
order phase transition coincides with that of the mean field theory regardless
of the size of the boundary region.


title:
Production-Level Facial Performance Capture Using Deep Convolutional
  Neural Networks

abstract:
  We present a real-time deep learning framework for video-based facial
performance capture -- the dense 3D tracking of an actor's face given a
monocular video. Our pipeline begins with accurately capturing a subject using
a high-end production facial capture pipeline based on multi-view stereo
tracking and artist-enhanced animations. With 5-10 minutes of captured footage,
we train a convolutional neural network to produce high-quality output,
including self-occluded regions, from a monocular video sequence of that
subject. Since this 3D facial performance capture is fully automated, our
system can drastically reduce the amount of labor involved in the development
of modern narrative-driven video games or films involving realistic digital
doubles of actors and potentially hours of animated dialogue per character. We
compare our results with several state-of-the-art monocular real-time facial
capture techniques and demonstrate compelling animation inference in
challenging areas such as eyes and lips.


title:
Electron transmission through a periodically driven graphene magnetic
  barrier

abstract:
  The kinetic transport of electrons through graphene magnetic barriers is
studied theoretically in presence of an external time harmonic scalar
potential. The transmission coefficients are calculated in the framework of the
non-perturbative Floquet theory using transfer matrix method. The time
dependent scalar potential is found to suppress the usual Fabry-Perot
oscillations occurring in the transmission through a constant vector potential
barrier (corresponding to two oppositely directed delta-function magnetic
barriers). Two types of asymmetric Fano resonances (FR) are noted and are
discussed for the narrow barrier structure. One of them arises due to the
oscillatory mode while the other due to the evanescent mode of the electron
wave inside the barrier. In contrast, the oscillating field favors the
transmission for rectangular magnetic barrier structure and also exhibits the
FR due to the presence of bound state inside the barrier. The characteristic
Fano line shape can be tuned by varying the amplitude of the oscillating
potential. The detection of such FR offers an efficient tool for the
identification of the quasi-bound and evanescent extended states inside the
barrier not reported in the literature so far, for the case of graphene
magnetic barrier structures.


title:
Discovery of a 0.42-s pulsar in the ultraluminous X-ray source NGC 7793
  P13

abstract:
  NGC 7793 P13 is a variable (luminosity range ~100) ultraluminous X-ray source
(ULX) proposed to host a stellar-mass black hole of less than 15 M$_{\odot}$ in
a binary system with orbital period of 64 d and a 18-23 M$_{\odot}$ B9Ia
companion. Within the EXTraS project we discovered pulsations at a period of
~0.42 s in two XMM-Newton observations of NGC 7793 P13, during which the source
was detected at $L_{\mathrm{X}}\sim2.1\times10^{39}$ and $5\times10^{39}$ erg
s$^{-1}$ (0.3-10 keV band). These findings unambiguously demonstrate that the
compact object in NGC 7793 P13 is a neutron star accreting at super-Eddington
rates. While standard accretion models face difficulties accounting for the
pulsar X-ray luminosity, the presence of a multipolar magnetic field with $B$ ~
few $\times$ 10$^{13}$ G close to the base of the accretion column appears to
be in agreement with the properties of the system.


title:
From galaxy-scale fueling to nuclear-scale feedback: the merger-state of
  radio galaxies 3C293, 3C305 & 4C12.50

abstract:
  Powerful radio galaxies are often associated with gas-rich galaxy mergers.
These mergers may provide the fuel to trigger starburst and active galactic
nuclear (AGN) activity. In this Research Note, we study the host galaxies of
three seemingly young or re-started radio sources that drive fast outflows of
cool neutral hydrogen (HI) gas, namely 3C 293, 3C 305 and 4C 12.50 (PKS
1345+12). Our aim is to link the feedback processes in the central kpc-scale
region with new information on the distribution of stars and gas at scales of
the galaxy. For this, we use deep optical V-band imaging of the host galaxies,
complemented with HI emission-line observations to study their gaseous
environments. We find prominent optical tidal features in all three radio
galaxies, which confirm previous claims that 3C 293, 3C 305 and 4C 12.50 have
been involved in a recent galaxy merger or interaction. Our data show the
complex morphology of the host galaxies, and identify the companion galaxies
that are likely involved in the merger or interaction. The radio sources appear
to be (re-)triggered at a different stage of the merger; 4C 12.50 is a
pre-coalescent and possibly multiple merger, 3C 293 is a post-coalescent merger
that is undergoing a minor interaction with a close satellite galaxy, while 3C
305 appears to be shaped by an interaction with a gas-rich companion. For 3C
293 and 3C 305, we do not detect HI beyond the inner ~30-45 kpc region, which
shows that the bulk of the cold gas is concentrated within the host-galaxy,
rather than along the widespread tidal features.


title:
All-sky census of Galactic high-latitude molecular intermediate-velocity
  clouds

abstract:
  The HI halo clouds of the Milky Way, and in particular the
intermediate-velocity clouds (IVCs), are thought to be connected to Galactic
fountain processes. Observations of fountain clouds are important for
understanding the role of matter recycling and accretion onto the Galactic disk
and subsequent star formation. Here, we quantify the amount of molecular gas in
the Galactic halo. We focus on the rare class of molecular IVCs (MIVCs) and
search for new objects. The HI-FIR correlation was studied across the entire
northern and southern Galactic hemispheres at Galactic latitudes $|b|>20^\circ$
to determine the amount and distribution of molecular gas in IVCs. We used the
most recent large-scale HI and FIR data, the Effelsberg Bonn-HI Survey, the
Parkes Galactic All-Sky Survey, and the Planck FIR surveys. We present a
catalogue of 239 MIVC candidates on the northern and southern Galactic
hemispheres. Among these candidates, all previously known MIVCs are recovered
except for one single source. The frequency of candidates differs significantly
between the northern and southern Galactic hemispheres and between negative and
positive LSR velocities as well. In our approach we analyse the local Galactic
environment. Extrapolating our results to the entire Galaxy, the global inflow
of atomic and molecular IVC gas onto the Milky Way may account for the major
fraction of the gaseous mass that is required to sustain the current Galactic
star formation rate.


title:
Mean-field beyond mean-field: the single particle view for moderately to
  strongly coupled charged fluids

abstract:
  In a counter-ion only charged fluid, Coulomb coupling is quantified by a
single dimensionless parameter. Yet, the theoretical treatment of moderately to
strongly coupled charged fluids is a difficult task, central to the
understanding of a wealth of soft matter problems, including biological
systems. We show that the corresponding coupling regime can be remarkably well
described by a single particle treatment, which, at variance with previous
works, takes due account of inter-ionic interactions. To this end, the
prototypical problem of a planar charged dielectric interface is worked out.
Testing our predictions against Monte Carlo simulation data reveals an
excellent agreement.


title:
Change-over of carrier type and magneto-transport property in Cu doped
  Bi2Te3 Topological Insulators

abstract:
  Structural, resistivity, thermoelectric power and magneto-transport
properties of Cu doped Bi2Te3 topological insulators have been investigated.
The occurrence of the tuning of charge carriers from n type to p type by Cu
doping at Te sites of Bi2Te3 is observed both from Hall effect and
thermoelectric power measurements. Carrier mobility decreases with the doping
of Cu which provides evidence of the movement of Fermi level from bulk
conduction band to the bulk valence band. Thermoelectric power also
increaseswith doping of Cu.Moreover linear magnetoresistance (LMR) has been
observed at high magnetic field in pure Bi2Te3 which is associated to the
gapless topological surface states protected by time reversal symmetry (TRS),
whereas doping of Cu breaks TRS and an opening of band gap occurs which
quenches the LMR.


title: Self impedance matched Hall-effect gyrators and circulators

abstract:
  We present a model study of an alternative implementation of a two-port
Hall-effect microwave gyrator. Our set-up involves three electrodes, one of
which acts as a common ground for the others. Based on the capacitive-coupling
model of Viola and DiVincenzo, we analyze the performance of the device and we
predict that ideal gyration can be achieved at specific frequencies.
Interestingly, the impedance of the three-terminal gyrator can be made
arbitrarily small for certain coupling strengths, so that no auxiliary
impedance matching is required. Although the bandwidth of the device shrinks as
the impedance decreases, it can be improved by reducing the magnetic field; it
can be realistically increased up to $ 150 \mathrm{MHz}$ at $50\mathrm{\Omega}$
by working at filling factor $\nu=10$. We examine also the effects of the
parasitic capacitive coupling between electrodes and we find that, although in
general they strongly influence the response of device, their effect is
negligible at low impedance. Finally, we analyze an interferometric
implementation of a circulator, which incorporates the gyrator in a
Mach-Zender-like construction. Perfect circulation in both directions can be
achieved, depending on frequency and on the details of the interferometer.


title:
Phase space analysis for a scalar-tensor model with kinetic and
  Gauss-Bonnet couplings

abstract:
  We study the phase space for an scalar-tensor string inspired model of dark
energy with non minimal kinetic and Gauss Bonnet couplings. The form of the
scalar potential and of the coupling terms is of the exponential type, which
give rise to appealing cosmological solutions. The critical points describe a
variety of cosmological scenarios that go from matter or radiation dominated
universe to dark energy dominated universe. There were found trajectories in
the phase space departing from unstable or saddle fixed points and arriving to
the stable scalar field dominated point corresponding to late-time accelerated
expansion.


title:
Data-driven nonlinear expectations for statistical uncertainty in
  decisions

abstract:
  In stochastic decision problems, one often wants to estimate the underlying
probability measure statistically, and then to use this estimate as a basis for
decisions. We shall consider how the uncertainty in this estimation can be
explicitly and consistently incorporated in the valuation of decisions, using
the theory of nonlinear expectations.

categories: math.ST math.OC math.PR q-fin.MF stat.TH


title:
An Eruptive Hot-Channel Structure Observed at Metric Wavelength as a
  Moving Type-IV Solar Radio Burst

abstract:
  Hot channel (HC) structure, observed in the high-temperature passbands of the
AIA/SDO, is regarded as one candidate of coronal flux rope which is an
essential element of solar eruptions. Here we present the first radio imaging
study of an HC structure in the metric wavelength. The associated radio
emission manifests as a moving type-IV (t-IVm) burst. We show that the radio
sources co-move outwards with the HC, indicating that the t-IV emitting
energetic electrons are efficiently trapped within the structure. The t-IV
sources at different frequencies present no considerable spatial dispersion
during the early stage of the event, while the sources spread gradually along
the eruptive HC structure at later stage with significant spatial dispersion.
The t-IV bursts are characterized by a relatively-high brightness temperature
($\sim$ 10$^{7}$ $-$ 10$^{9}$ K), a moderate polarization, and a spectral shape
that evolves considerably with time. This study demonstrates the possibility of
imaging the eruptive HC structure at the metric wavelength and provides strong
constraints on the t-IV emision mechanism, which, if understood, can be used to
diagnose the essential parameters of the eruptive structure.


title:
A high-throughput analysis of ovarian cycle disruption by mixtures of
  aromatase inhibitors

abstract:
  Background: Combining computational toxicology with ExpoCast exposure
estimates and ToxCast assay data gives us access to predictions of human health
risks stemming from exposures to chemical mixtures.
  Objectives: To explore, through mathematical modeling and simulations, the
size of potential effects of random mixtures of aromatase inhibitors on the
dynamics of women's menstrual cycles.
  Methods: We simulated random exposures to millions of potential mixtures of
86 aromatase inhibitors. A pharmacokinetic model of intake and disposition of
the chemicals predicted their internal concentration as a function of time (up
to two years). A ToxCast aromatase assay provided concentration-inhibition
relationships for each chemical. The resulting total aromatase inhibition was
input to a mathematical model of the hormonal hypothalamus-pituitary-ovarian
control of ovulation in women.
  Results: Above 10% inhibition of estradiol synthesis by aromatase inhibitors,
noticeable (eventually reversible) effects on ovulation were predicted.
Exposures to individual chemicals never led to such effects. In our best
estimate, about 10% of the combined exposures simulated had mild to
catastrophic impacts on ovulation. A lower bound on that figure, obtained using
an optimistic exposure scenario, was 0.3%.
  Conclusions: These results demonstrate the possibility to predict large-scale
mixture effects for endocrine disrupters with a predictive toxicology approach,
suitable for high-throughput ranking and risk assessment. The size of the
effects predicted is consistent with an increased risk of infertility in women
from everyday exposures to our chemical environment.


title:
Analytic Solution of the Ornstein-Zernike Relation for Inhomogeneous
  Liquids

abstract:
  The properties of a classical simple liquid can be strongly affected by
application of an external potential that supports inhomogeneity. To understand
the nature of these property changes the equilibrium particle distribution
functions of the liquid have, typically, been evaluated individually as
functions of system control parameters, such as the packing fraction of a hard
sphere liquid. In this study we focus attention on two distribution functions
that characterize the inhomogeneous liquid: the pair direct correlation
function $c(\mathbf{r}_1,\mathbf{r}_2)$ and the pair correlation function
$g(\mathbf{r}_1,\mathbf{r}_2)$. We solve the Ornstein-Zernike equation for the
inhomogeneous liquid to obtain $c(\mathbf{r}_1,\mathbf{r}_2)$ as an explicit
function of $g(\mathbf{r}_1,\mathbf{r}_2)$, with the latter considered to be an
experimental observable, using information about the well studied and resolved
$g^0(\mathbf{r}_1-\mathbf{r}_2)$ and $c^0(\mathbf{r}_1-\mathbf{r}_2)$ for the
parent homogeneous ($^0$) system. The result obtained with our formulation is
tested against the exact solutions for the correlation and distribution
functions of a one-dimensional inhomogeneous hard rod liquid. Following the
success of that test the formalism is extended to obtain
$c(\mathbf{r}_1,\mathbf{r}_2)$ as an explicit function of
$g(\mathbf{r}_1,\mathbf{r}_2)$ in a three dimensional liquid.


title:
Exploring the Venus global super-rotation using a comprehensive General
  Circulation Model

abstract:
  The atmospheric circulation in Venus is well known to exhibit strong
super-rotation. However, the atmospheric mechanisms responsible for the
formation of this super-rotation are still not fully understood. In this work,
we developed a new Venus general circulation model to study the most likely
mechanisms driving the atmosphere to the current observed circulation. Our
model includes a new radiative transfer, convection and suitably adapted
boundary layer schemes and a dynamical core that takes into account the
dependence of the heat capacity at constant pressure with temperature.
  The new Venus model is able to simulate a super-rotation phenomenon in the
cloud region quantitatively similar to the one observed. The mechanisms
maintaining the strong winds in the cloud region were found in the model
results to be a combination of zonal mean circulation, thermal tides and
transient waves. In this process, the semi-diurnal tide excited in the upper
clouds has a key contribution in transporting axial angular momentum mainly
from the upper atmosphere towards the cloud region. The magnitude of the
super-rotation in the cloud region is sensitive to various radiative parameters
such as the amount of solar radiative energy absorbed by the surface, which
controls the static stability near the surface. In this work, we also discuss
the main difficulties in representing the flow below the cloud base in Venus
atmospheric models.
  Our new radiative scheme is more suitable for 3D Venus climate models than
those used in previous work due to its easy adaptability to different
atmospheric conditions. This flexibility of the model was crucial to explore
the uncertainties in the lower atmospheric conditions and may also be used in
the future to explore, for example, dynamical-radiative-microphysical
feedbacks.


title:
Measurement of the relative yields of $\psi(2S)$ to $\psi(1S)$ mesons
  produced at forward and backward rapidity in $p$$+$$p$, $p$$+$Al, $p$$+$Au,
  and $^{3}$He$+$Au collisions at $\sqrt{s_{_{NN}}}=200$ GeV

abstract:
  The PHENIX Collaboration has measured the ratio of the yields of $\psi(2S)$
to $\psi(1S)$ mesons produced in $p$$+$$p$, $p$$+$Al, $p$$+$Au, and
$^{3}$He$+$Au collisions at $\sqrt{s_{_{NN}}}=200$ GeV over the forward and
backward rapidity intervals $1.2<|y|<2.2$. We find that the ratio in $p$$+$$p$
collisions is consistent with measurements at other collision energies. In
collisions with nuclei, we find that in the forward ($p$-going or
$^{3}$He-going) direction, the relative yield of $\psi(2S)$ mesons to
$\psi(1S)$ mesons is consistent with the value measured in \pp collisions.
However, in the backward (nucleus-going) direction, the $\psi(2S)$ is
preferentially suppressed by a factor of $\sim$2. This suppression is
attributed in some models to breakup of the weakly-bound $\psi(2S)$ through
final state interactions with comoving particles, which have a higher density
in the nucleus-going direction. These breakup effects may compete with color
screening in a deconfined quark-gluon plasma to produce sequential suppression
of excited quarkonia states.