title:
Network Densification in 5G: From the Short-Range Communications
  Perspective

abstract:
  Besides advanced telecommunications techniques, the most prominent evolution
of wireless networks is the densification of network deployment. In particular,
the increasing access points/users density and reduced cell size significantly
enhance spatial reuse, thereby improving network capacity. Nevertheless, does
network ultra-densification and over-deployment always boost the performance of
wireless networks? Since the distance from transmitters to receivers is greatly
reduced in dense networks, signal is more likely to be propagated from long- to
short-range region. Without considering short-range propagation features,
conventional understanding of the impact of network densification becomes
doubtful. With this regard, it is imperative to reconsider the pros and cons
brought by network densification. In this article, we first discuss the
short-range propagation features in densely deployed network and verify through
experimental results the validity of the proposed short-range propagation
model. Considering short-range propagation, we further explore the fundamental
impact of network densification on network capacity, aided by which a concrete
interpretation of ultra-densification is presented from the network capacity
perspective. Meanwhile, as short-range propagation makes interference more
complicated and difficult to handle, we discuss possible approaches to further
enhance network capacity in ultra-dense wireless networks. Moreover, key
challenges are presented to suggest future directions.


title: Multi-Modal Hybrid Deep Neural Network for Speech Enhancement

abstract:
  Deep Neural Networks (DNN) have been successful in en- hancing noisy speech
signals. Enhancement is achieved by learning a nonlinear mapping function from
the features of the corrupted speech signal to that of the reference clean
speech signal. The quality of predicted features can be improved by providing
additional side channel information that is robust to noise, such as visual
cues. In this paper we propose a novel deep learning model inspired by insights
from human audio visual perception. In the proposed unified hybrid
architecture, features from a Convolution Neural Network (CNN) that processes
the visual cues and features from a fully connected DNN that processes the
audio signal are integrated using a Bidirectional Long Short-Term Memory
(BiLSTM) network. The parameters of the hybrid model are jointly learned using
backpropagation. We compare the quality of enhanced speech from the hybrid
models with those from traditional DNN and BiLSTM models.


title:
The QUAX-g_p g_s experiment to search for monopole-dipole Axion
  interaction

abstract:
  The QCD axion is an hypothetical particle introduced to solve the strong CP
problem of standard model of particle physics and is of interest as a possible
component of cold dark matter. In the axion scenario, J.E. Moody and F. Wilczek
showed that a new macroscopic long-range force, mediated by axion exchange,
acts on electron spins, and that such force can be described in terms of an
effective magnetic field. The QUAX-g$_p$g$_s$ experiment, carried out at INFN
Laboratori Nazionali di Legnaro, is designed to search for the effects on
magnetized samples of the effective field produced by unpolarized mass sources.
As this field is macroscopic, it can be detected by measuring the change of
magnetization of a paramagnetic Gadolinium silicate (GSO) crystal cooled at
liquid helium temperature. The axion effective field induced magnetization can
be detected with a SQUID magnetometer. By varying the position of the of source
masses, the induced GSO magnetization is modulated at acoustic frequencies.
Although the full QUAX-g$_p$g$_s$ sensitivity has not been yet exploited, we
are able to measure a magnetization of $10^{-17}~$T at few tens of Hz. With
this sensitivity we expect to further improve the upper limit of the coupling
of the predicted long-range force in the $10^{-3}$ to $1~$m interval.


title:
Generator masas in $q$-deformed Araki-Woods von Neumann algebras and
  factoriality

abstract:
  To any strongly continuous orthogonal representation of $\R$ on a real
Hilbert space $\CH_\R$, Hiai constructed $q$-deformed Araki-Woods von Neumann
algebras for $-1< q< 1$, which are $W^{\ast}$-algebras arising from non tracial
representations of the $q$-commutation relations, the latter yielding an
interpolation between the Bosonic and Fermionic statistics. We prove that if
the orthogonal representation is not ergodic then these von Neumann algebras
are factors whenever $dim(\CH_\R)\geq 2$ and $q\in (-1,1)$. In such case, the
centralizer of the $q$-quasi free state has trivial relative commutant. In the
process, we study `generator masas' in these factors and establish that they
are strongly mixing. The analysis is inspired by a previous work of \'{E}.
Ricard on Bo$\overset{.}{\text{z}}$ejko-Speicher's factors \cite{ER} and
measure-multiplicity invariant of masas introduced by K. Dykema, A. Sinclair
and R. Smith in \cite{DSS06}.


title:
Safe Exploration in Finite Markov Decision Processes with Gaussian
  Processes

abstract:
  In classical reinforcement learning, when exploring an environment, agents
accept arbitrary short term loss for long term gain. This is infeasible for
safety critical applications, such as robotics, where even a single unsafe
action may cause system failure. In this paper, we address the problem of
safely exploring finite Markov decision processes (MDP). We define safety in
terms of an, a priori unknown, safety constraint that depends on states and
actions. We aim to explore the MDP under this constraint, assuming that the
unknown function satisfies regularity conditions expressed via a Gaussian
process prior. We develop a novel algorithm for this task and prove that it is
able to completely explore the safely reachable part of the MDP without
violating the safety constraint. To achieve this, it cautiously explores safe
states and actions in order to gain statistical confidence about the safety of
unvisited state-action pairs from noisy observations collected while navigating
the environment. Moreover, the algorithm explicitly considers reachability when
exploring the MDP, ensuring that it does not get stuck in any state with no
safe way out. We demonstrate our method on digital terrain models for the task
of exploring an unknown map with a rover.


title:
A Correlational Encoder Decoder Architecture for Pivot Based Sequence
  Generation

abstract:
  Interlingua based Machine Translation (MT) aims to encode multiple languages
into a common linguistic representation and then decode sentences in multiple
target languages from this representation. In this work we explore this idea in
the context of neural encoder decoder architectures, albeit on a smaller scale
and without MT as the end goal. Specifically, we consider the case of three
languages or modalities X, Z and Y wherein we are interested in generating
sequences in Y starting from information available in X. However, there is no
parallel training data available between X and Y but, training data is
available between X & Z and Z & Y (as is often the case in many real world
applications). Z thus acts as a pivot/bridge. An obvious solution, which is
perhaps less elegant but works very well in practice is to train a two stage
model which first converts from X to Z and then from Z to Y. Instead we explore
an interlingua inspired solution which jointly learns to do the following (i)
encode X and Z to a common representation and (ii) decode Y from this common
representation. We evaluate our model on two tasks: (i) bridge transliteration
and (ii) bridge captioning. We report promising results in both these
applications and believe that this is a right step towards truly interlingua
inspired encoder decoder architectures.


title:
Quantized Vortices and Four-Component Superfluidity of Semiconductor
  Excitons

abstract:
  We study spatially indirect excitons of GaAs quantum wells, confined in a 10
microns electrostatic trap. Below a critical temperature of about 1 Kelvin, we
detect macroscopic spatial coherence and quantised vortices in the weak
photoluminescence emitted from the trap. These quantum signatures are
restricted to a narrow range of density, in a dilute regime. They manifest the
formation of a four-component superfluid, made by a low population of optically
bright excitons coherently coupled to a dominant fraction of optically dark
excitons.


title: The generalized r-Whitney numbers

abstract:
  In this paper, we define the generalized r-Whitney numbers of the first and
second kind. Moreover, we drive the generalized Whitney numbers of the first
and second kind. The recurrence relations and the generating functions of these
numbers are derived. The relations between these numbers and generalized
Stirling numbers of the first and second kind are deduced. Furthermore, some
special cases are given. Finally, matrix representation of The relations
between Whitney and Stirling numbers are given.


title:
Dirichlet spectrum of the paradigm model of complex PT-symmetric
  potential: $V(x)=-(ix)^N$

abstract:
  So far the spectra $E_n(N)$ of the paradigm model of complex
PT(Parity-Time)-symmetric potential $V_{BB}(x,N)=-(ix)^N$ is known to be
analytically continued for $N > 4$. Consequently, the well known eigenvalues of
the Hermitian cases ($N=6,10$) cannot be recovered. Here, we illustrate Kato's
theorem that even if a Hamiltonian $H(\lambda)$ is an analytic function of a
real parameter $\lambda$, its eigenvalues $E_n(\lambda)$ may not be analytic at
finite number of Isolated Points (IPs). In this light, we present the Dirichlet
spectra $E_n(N)$ of $V_{BB}(x,N)$ for $2\le N<12$ using the numerical
integration of Schr{\"o}dinger equation with $\psi(x=\pm \infty)=0$ and the
diagonalization of $H=p^2/2\mu+V_{BB}(x,N)$ in the harmonic oscillator basis.
We show that these real discrete spectra are consistent with the most simple
two-turning point CWKB (C refers to complex turning points) method provided we
choose the maximal turning points (MxTP) [$-a+ib,a+ib, a, b \in {\cal R}$] such
that $|a|$ is the largest for a given energy among all (multiple) turning
points. We find that $E_n(N)$ are continuous function of $N$ but non-analytic
(their first derivative is discontinuous) at IPs $N=4,8$; where the Dirichlet
spectrum is null (as $V_{BB}$ becomes a Hermitian flat-top potential barrier).
At $N=6$ and $10$, $V_{BB}(x,N)$ becomes a Hermitian well and we recover its
well known eigenvalues.


title:
The ${\Upsilon}(nS)$ ${\to}$ $B_{c}^{\ast}{\pi}$, $B_{c}^{\ast}K$ decays
  with perturbative QCD approach

abstract:
  Besides the traditional strong and electromagnetic decay modes,
${\Upsilon}(nS)$ meson can also decay through the weak interactions within the
standard model of elementary particle. With anticipation of copious
${\Upsilon}(nS)$ data samples at the running LHC and coming SuperKEKB
experiments, the two-body nonleptonic bottom-changing ${\Upsilon}(nS)$ ${\to}$
$B_{c}^{\ast}{\pi}$, $B_{c}^{\ast}K$ decays ($n$ $=$ 1, 2, 3) are investigated
with perturbative QCD approach firstly. The absolute branching ratios for
${\Upsilon}(nS)$ ${\to}$ $B_{c}^{\ast}{\pi}$ and $B_{c}^{\ast}K$ decays are
estimated to reach up to about $10^{-10}$ and $10^{-11}$, respectively, which
might possibly be measured by the future experiments.


title: A minimalist approach to conceptualization of time in quantum theory

abstract:
  Ever since Schrodinger, Time in quantum theory is postulated Newtonian for
every reference frame. With the help of certain known mathematical results, we
show that the concept of the so-called Local Time allows avoiding the
postulate. In effect, time appears as neither fundamental nor universal on the
quantum-mechanical level while being consistently attributable to every, at
least approximately, closed quantum system as well as to every of its
(conservative or not) subsystems.


title: Adapting to unknown noise level in sparse deconvolution

abstract:
  In this paper, we study sparse spike deconvolution over the space of
complex-valued measures when the input measure is a finite sum of Dirac masses.
We introduce a modified version of the Beurling Lasso (BLasso), a semi-definite
program that we refer to as the Concomitant Beurling Lasso (CBLasso). This new
procedure estimates the target measure and the unknown noise level
simultaneously. Contrary to previous estimators in the literature, theory holds
for a tuning parameter that depends only on the sample size, so that it can be
used for unknown noise level problems. Consistent noise level estimation is
standardly proved. As for Radon measure estimation, theoretical guarantees
match the previous state-of-the-art results in Super-Resolution regarding
minimax prediction and localization. The proofs are based on a bound on the
noise level given by a new tail estimate of the supremum of a stationary
non-Gaussian process through the Rice method.


title: Probabilistic Interpretation for Correntropy with Complex Data

abstract:
  Recent studies have demonstrated that correntropy is an efficient tool for
analyzing higher-order statistical moments in nonGaussian noise environments.
Although it has been used with complex data, some adaptations were then
necessary without deriving a generic form so that similarities between complex
random variables can be aggregated. This paper presents a novel probabilistic
interpretation for correntropy using complex-valued data called complex
correntropy. An analytical recursive solution for the maximum complex
correntropy criterion (MCCC) is introduced as based on the fixedpoint solution.
This technique is applied to a simple system identification case study, as the
results demonstrate prominent advantages regarding the proposed cost function
if compared to the complex recursive least squares (RLS) algorithm. By using
such probabilistic interpretation, correntropy can be applied to solve several
problems involving complex data in a more straightforward way.


title: Birational Chow-K\"unneth decompositions

abstract:
  We study the notion of a birational Chow-K\"unneth decomposition, which is
essentially a decomposition of the integral birational motive of a variety. The
existence of a birational Chow-K\"unneth decomposition is stably birationally
invariant and this notion refines the Chow theoretical decomposition of the
diagonal. We show that a birational Chow-K\"unneth decompostion exists for the
following varieties: (a) Jacobian variety; (b) Hilbert scheme of points on a
$K3$ surface and (c) The variety of lines on a stably rational cubic threefold
or a stably rational cubic fourfold.


title: A Simple Streaming Bit-parallel Algorithm for Swap Pattern Matching

abstract:
  The pattern matching problem with swaps is to find all occurrences of a
pattern in a text while allowing the pattern to swap adjacent symbols. The goal
is to design fast matching algorithm that takes advantage of the bit
parallelism of bitwise machine instructions and has only streaming access to
the input. We introduce a new approach to solve this problem based on the graph
theoretic model and compare its performance to previously known algorithms. We
also show that an approach using deterministic finite automata cannot achieve
similarly efficient algorithms. Furthermore, we describe a fatal flaw in some
of the previously published algorithms based on the same model. Finally, we
provide experimental evaluation of our algorithm on real-world data.


title: Resonant spectra of quadrupolar anions

abstract:
  In quadrupole-bound anions, an extra electron is attached at a sufficiently
large quadrupole moment of a neutral molecule, which is lacking a permanent
dipole moment. The nature of the bound states and low-lying resonances of such
anions is of interest for understanding the threshold behavior of open quantum
systems in general. In this work, we investigate the properties of quadrupolar
anions as extreme halo systems, the formation of rotational bands, and the
transition from a subcritical to supercritical electric quadrupole moment. We
solve the electron-plus-molecule problem using a non-adiabatic coupled-channel
formalism by employing the Berggren ensemble, which explicitly contains bound
states, narrow resonances, and the scattering continuum. We demonstrate that
binding energies and radii of quadrupolar anions strictly follow the scaling
laws for two-body halo systems. Contrary to the case of dipolar anions,
ground-state band of quadrupolar anions smoothly extend into the continuum, and
many rotational bands could be identified above the detachment threshold. We
study the evolution of a bound state of an anion as to dives into the continuum
at a critical quadrupole moment and we show that the associated critical
exponent is consistent with the second-order phase transition. Everything
considered, quadrupolar anions represent a perfect laboratory for the studies
of marginally bound open quantum systems.


title: Maximal independent sets in Borel graphs and large cardinals

abstract:
  We construct a Borel graph G such that ZF+DC+"There are no maximal
independent sets in G" is equiconsistent with ZFC+"There exists an inaccessible
cardinal".


title:
Probe-based Rapid Hybrid Hyperspectral and Tissue Surface Imaging Aided
  by Fully Convolutional Networks

abstract:
  Tissue surface shape and reflectance spectra provide rich intra-operative
information useful in surgical guidance. We propose a hybrid system which
displays an endoscopic image with a fast joint inspection of tissue surface
shape using structured light (SL) and hyperspectral imaging (HSI). For SL a
miniature fibre probe is used to project a coloured spot pattern onto the
tissue surface. In HSI mode standard endoscopic illumination is used, with the
fibre probe collecting reflected light and encoding the spatial information
into a linear format that can be imaged onto the slit of a spectrograph.
Correspondence between the arrangement of fibres at the distal and proximal
ends of the bundle was found using spectral encoding. Then during pattern
decoding, a fully convolutional network (FCN) was used for spot detection,
followed by a matching propagation algorithm for spot identification. This
method enabled fast reconstruction (12 frames per second) using a GPU. The
hyperspectral image was combined with the white light image and the
reconstructed surface, showing the spectral information of different areas.
Validation of this system using phantom and ex vivo experiments has been
demonstrated.


title:
Consistency relations and conservation of $\zeta$ in holographic
  inflation

abstract:
  It is well known that, in single clock inflation, the curvature perturbation
$\zeta$ is constant in time on superhorizon scales. In the standard bulk
description this follows quite simply from the local conservation of the energy
momentum tensor in the bulk. On the other hand, in a holographic description,
the constancy of the curvature perturbation must be related to the properties
of the RG flow in the boundary theory. Here, we show that, in single clock
holographic inflation, the time independence of correlators of $\zeta$ follows
from the cut-off independence of correlators of the energy momentum tensor in
the boundary theory, and from the so-called consistency relations for vertex
functions with a soft leg.


title:
Weighted vector-valued bounds for a class of multilinear singular
  integral operators

abstract:
  In this paper, we investigate the weighted vector-valued bounds for a class
of multilinear singular integral operators, and its commutators, from
$L^{p_1}(l^{q_1};\,\mathbb{R}^n,w_1)\times\dots\times
L^{p_m}(l^{q_m};\,\mathbb{R}^n,w_m)$ to
$L^{p}(l^q;\,\mathbb{R}^n,\nu_{\vec{w}})$, with $p_1,\dots,p_m\in (1,\,\infty)$
and $1/p=1/p_1+\dots+1/p_m$ and $\vec{w}$ is a multiple $A_{\vec{P}}$ weights.
Our argument also leads to the weighted weak type endpoint estimates for the
commutators.


title: Quantum character varieties and braided module categories

abstract:
  We compute quantum character varieties of arbitrary closed surfaces with
boundaries and marked points. These are categorical invariants $\int_S\mathcal
A$ of a surface $S$, determined by the choice of a braided tensor category
$\mathcal A$, and computed via factorization homology.
  We identify the algebraic data governing marked points and boundary
components with the notion of a {\em braided module category} for $\mathcal A$,
and we describe braided module categories with a generator in terms of certain
explicit algebra homomorphisms called {\em quantum moment maps}. We then show
that the quantum character variety of a decorated surface is obtained from that
of the corresponding punctured surface as a quantum Hamiltonian reduction.
  Characters of braided $\mathcal A$-modules are objects of the torus category
$\int_{T^2}\mathcal A$. We initiate a theory of character sheaves for quantum
groups by identifying the torus integral of $\mathcal A=\operatorname{Rep_q} G$
with the category $\mathcal D_q(G/G)-\operatorname{mod}$ of equivariant quantum
$\mathcal D$-modules. When $G=GL_n$, we relate the mirabolic version of this
category to the representations of the spherical double affine Hecke algebra
(DAHA) $\mathbb{SH}_{q,t}$.


title: An improved lower bound for finite additive 2-bases

abstract:
  A set of non-negative integers A is an additive 2-basis with range n, if its
sumset A+A contains 0, 1, ..., n but not n+1. Explicit bases are known with
arbitrarily large size |A|=k and $n/k^2 \ge 2/7 > 0.2857$. We present a more
general construction and improve the lower bound to $85/294 > 0.2891$.


title: Moments and Entropy of the Interpolating Family of Size Distributions

abstract:
  Sinner et al. (2016) recently introduced a five-parameter family of size
distributions, coined Interpolating Family or IF distribution for short. In
this complementary note, we take advantage of the tractability of the IF
distribution to compute the moments and the differential entropy. As a
consequence, we deduce at a single stroke the corresponding expressions for
many well-known size distributions arising as special cases of the IF
distribution.


title: $\alpha_s$ review (2016)

abstract:
  The current world-average of the strong coupling at the Z pole mass,
$\alpha_s(m^2_{Z}) = 0.1181 \pm 0.0013$, is obtained from a comparison of
perturbative QCD calculations computed, at least, at
next-to-next-to-leading-order accuracy, to a set of 6 groups of experimental
observables: (i) lattice QCD "data", (ii) $\tau$ hadronic decays, (iii) proton
structure functions, (iv) event shapes and jet rates in $e^+e^-$ collisions,
(v) Z boson hadronic decays, and (vi) top-quark cross sections in p-p
collisions. In addition, at least 8 other $\alpha_s$ extractions, usually with
a lower level of theoretical and/or experimental precision today, have been
proposed: pion, $\Upsilon$, W hadronic decays; soft and hard fragmentation
functions; jets cross sections in pp, e-p and $\gamma$-p collisions; and photon
F$_2$ structure function in $\gamma\,\gamma$ collisions. These 14 $\alpha_s$
determinations are reviewed, and the perspectives of reduction of their present
uncertainties are discussed.


title: A properly infinite C*-algebra which is not K_1-injective

abstract:
  We construct in this note a unital properly infinite C*-algebra which is not
K$_1$-injective.


title:
Free Form based active contours for image segmentation and free space
  perception

abstract:
  In this paper we present a novel approach for representing and evolving
deformable active contours. The method combines piecewise regular B{\'e}zier
models and curve evolution defined by local Free Form Deformation. The contour
deformation is locally constrained which allows contour convergence with almost
linear complexity while adapting to various shape settings and handling
topology changes of the active contour.
  We demonstrate the effectiveness of the new active contour scheme for visual
free space perception and segmentation using omnidirectional images acquired by
a robot exploring unknown indoor and outdoor environments. Several experiments
validate the approach with comparison to state-of-the art parametric and
geometric active contours and provide fast and real-time robot free space
segmentation and navigation.


title: Mapping spaces and automorphism groups of toric noncommutative spaces

abstract:
  We develop a sheaf theory approach to toric noncommutative geometry which
allows us to formalize the concept of mapping spaces between two toric
noncommutative spaces. As an application we study the `internalized'
automorphism group of a toric noncommutative space and show that its Lie
algebra has an elementary description in terms of braided derivations.


title:
A geometric criterion for equation $\dot{x}=\sum^m_{i=0}a_i(t)x^i$
  having at most $m$ isolated periodic solutions

abstract:
  This paper is devoted to the investigation of generalized Abel equation
$\dot{x}=S(x,t)=\sum^m_{i=0}a_i(t)x^i$, where $a_i\in\mathrm
C^{\infty}([0,1])$. A solution $x(t)$ is called a {\em periodic solution} if
$x(0)=x(1)$. In order to estimate the number of isolated periodic solutions of
the equation, we propose a hypothesis (H) which is only concerned with $S(x,t)$
on $m$ straight lines: There exist $m$ real numbers
$\lambda_1<\cdots<\lambda_m$ such that either $(-1)^i\cdot S(\lambda_i,t)\geq0$
for $i=1,\cdots,m$, or $(-1)^i\cdot S(\lambda_i,t)\leq0$ for $i=1,\cdots,m$. By
means of Lagrange interpolation formula, we proves that the equation has at
most $m$ isolated periodic solutions (counted with multiplicities) if
hypothesis (H) holds, and the upper bound is sharp. Furthermore, this
conclusion is also obtained under some weaker geometric hypotheses.
  Applying our main result for the trigonometrical generalized Abel equation
with coefficients of degree one, we give a criterion to obtain the upper bound
for the number of isolated periodic solutions. This criterion is "almost
equivalent" to hypothesis (H) and can be much more effectively checked.


title: Axially Symmetric Shear-free Fluids in $f(R,T)$ Gravity

abstract:
  In this work we have discussed the implications of shear-free condition on
axially symmetric anisotropic gravitating objects in $f(R,T)$ theory.
Restricted axial symmetry ignoring rotation and reflection enteries is taken
into account for establishment of instability range. Implementation of linear
perturbation on constitutive modified dynamical equations yield evolution
equation. This equation associates adiabatic index $\Gamma$ with material and
dark source components defining stable and unstable regions in Newtonian (N)
and post-Newtonian (pN) approximations.


title:
The Learning and Prediction of Application-level Traffic Data in
  Cellular Networks

abstract:
  Traffic learning and prediction is at the heart of the evaluation of the
performance of telecommunications networks and attracts a lot of attention in
wired broadband networks. Now, benefiting from the big data in cellular
networks, it becomes possible to make the analyses one step further into the
application level. In this paper, we firstly collect a significant amount of
application-level traffic data from cellular network operators. Afterwards,
with the aid of the traffic "big data", we make a comprehensive study over the
modeling and prediction framework of cellular network traffic. Our results
solidly demonstrate that there universally exist some traffic statistical
modeling characteristics, including ALPHA-stable modeled property in the
temporal domain and the sparsity in the spatial domain. Meanwhile, the results
also demonstrate the distinctions originated from the uniqueness of different
service types of applications. Furthermore, we propose a new traffic prediction
framework to encompass and explore these aforementioned characteristics and
then develop a dictionary learning-based alternating direction method to solve
it. Besides, we validate the prediction accuracy improvement and the robustness
of the proposed framework through extensive simulation results.


title: Group Actions on Winning Games of Super Tic-Tac-Toe

abstract:
  Consider a $n \times n$ tic-tac-toe board. In each field of the board, draw a
smaller $n\times n$ tic-tac-toe board. Now let super tic-tac-toe (STTT) be a
game where each player's move dictates which field on the larger board a player
must make their next move. We will play an impartial game of STTT where each
player uses X. We define a set of actions on a game board which gives rise to a
group-action on the game that creates equivalent games. We will discuss how the
structure of this group-action forms a Dihedral group.


title:
An analytical solution of the gyrokinetic equation for the calculation
  of neoclassical effects

abstract:
  The purpose of this document is to find an analytical solution for the
gyrokinetic equation under specific, simplificative hypotheses. The case I am
considering is that of a collisional plasma in the presence of a chain of
magnetic islands. The presence of the magnetic islands causes the onset of
perturbative fields, in particular an electrostatic field, with a gradient
length-scale comparable with the island's width. When the island's width w
becomes comparable with the ion Larmor radius rho_i , the drift-kinetic
equation is inadequate to treat the transport and the calculation of the
neoclassical effects. Nevertheless, I'm going to solve the equation with the
methods described by S. P. Hirshman and D. J. Sigmar in the review paper
"Neoclassical transport of impurities in tokamak plasmas", which was developed
to solve the drift-kinetic equation in different regimes of collisionality. I'm
going to remind first the drift-kinetic theory, which was largely used to study
classical and neoclassical transport in magnetized plasmas. Then I'm moving to
the gyrokinetic theory, which brings to a more complicated kinetic equation,
and I'm going to solve it by applying the approach used previously by Hirshman
& Sigmar.


title: Instantaneous Bethe-Salpeter View of Goldstone-Type Pseudoscalar Mesons

abstract:
  Describing the lightest pseudoscalar mesons as bound states of quark and
antiquark within the framework of an instantaneous Bethe-Salpeter formalism
constructed such as to retain (in contrast to Salpeter's equation) as much
information on the relativistic effects provided by the full quark propagator
as conceivable allows for a surprisingly simple implementation of their near
masslessness mandatory for their interpretability as pseudo-Goldstone bosons
related to the spontaneous breaking of the chiral symmetries of quantum
chromodynamics.


title:
Search for pair production of Higgs bosons in the $b\bar{b}b\bar{b}$
  final state using proton--proton collisions at $\sqrt{s} = 13$ TeV with the
  ATLAS detector

abstract:
  A search for Higgs-boson pair production in the $b\bar{b}b\bar{b}$ final
state is carried out with 3.2 fb$^{-1}$ of proton--proton collision data
collected at $\sqrt{s} = 13$ TeV with the ATLAS detector. The data are
consistent with the estimated background and are used to set upper limits on
the production cross section of Higgs-boson pairs times branching ratio to
$b\bar{b}b\bar{b}$ for both nonresonant and resonant production. In the case of
resonant production of Kaluza--Klein gravitons within the Randall--Sundrum
model, upper limits in the 24 to 91 fb range are obtained for masses between
600 and 3000 GeV, at the 95% confidence level. The production cross section
times branching ratio for nonresonant Higgs-boson pairs is also constrained to
be less than 1.22 pb, at the 95% confidence level.


title:
Field Induced Quantum Phase Transitions in $S=1/2$ $J_1$-$J_2$
  Heisenberg Model on the Square Lattice

abstract:
  We study the magnetic field dependence of the ground state of $S=1/2$
$J_1$-$J_2$ Heisenberg model on the square lattice by the DMRG method with the
sine-square deformation. We obtain 8 different phases including plaquette
valence-bond crystal with a finite spin gap, transverse N$\acute{\rm e}$el,
transverse stripe, 1/2 magnetization plateau with up-up-up-down (uuud), and
three new phases we named Y-like, V-like, and $\Psi$ phases around $J_2/J_1$
=0.55-0.6 depending on the magnetic field. The phase transitions to uuud and
Y-like states from transverse N$\acute{\rm e}$el (at $J_2/J_1$ = 0.55) and
stripe (at $J_2/J_1$ = 0.6) states are discontinuous, as in the case of
spin-flop.


title:
Signature of the Leggett mode in the A1g Raman response: from MgB2 to
  iron-based superconductors

abstract:
  The Raman response in a superconductor is a powerful probe to investigate the
symmetry of the superconducting gap. Here we show that in a multiband
superconductor it also offers the unique opportunity to establish if the
driving pairing interaction has an intraband or interband character. In the
model with one hole and one electron band the full gauge-invariant Raman
response, obtained by accounting for the fluctuations of both the density and
superconducting phase degrees of freedom, is always dominated by the Leggett
mode, regardless its nature. However, while in the case of intra-band dominated
pairing the Josephson-like phase fluctuations of the two condensates identify a
well-defined peak, as observed in MgB$_2$, for dominant interband pairing the
Leggett resonance is pushed at twice the largest gap, resembling apparently a
pair-breaking peak. The latter case is in very good agreement with experimental
data in iron-based superconductors, suggesting that an interband pairing
mechanism should be at play in these systems. These results have also
interesting implications for the non-linear optical response probed by means of
intense THz fields.


title:
Computation of dynamical correlation functions for many fermion systems
  with auxiliary-field quantum Monte Carlo

abstract:
  We address the calculation of dynamical correlation functions for many
fermion systems at zero temperature, using the auxiliary-field quantum Monte
Carlo method. The two-dimensional Hubbard hamiltonian is used as a model
system. Although most of the calculations performed here are for cases where
the sign problem is absent, the discussions are kept general for applications
to physical problems when the sign problem does arise. We study the use of
twisted boundary conditions to improve the extrapolation of the results to the
thermodynamic limit. A strategy is proposed to drastically reduce finite size
effects relying on a minimization among the twist angles. This approach is
demonstrated by computing the charge gap at half-filling. We obtain accurate
results showing the scaling of the gap with the interaction strength $U$,
connecting to the scaling of the unrestricted Hartree-Fock method at small $U$
and Bethe Ansatz exact result in one dimension at large $U$. A new algorithm is
then proposed to compute dynamical Green functions and correlation functions
which explicitly varies the number of particles during the random walks in the
manifold of Slater determinants. In dilute systems, such as ultracold Fermi
gases, this algorithm enables calculations with much more favorable complexity,
with computational cost proportional to basis size or the number of lattice
sites.


title: A Survey of Satisfiability Modulo Theory

abstract:
  Satisfiability modulo theory (SMT) consists in testing the satisfiability of
first-order formulas over linear integer or real arithmetic, or other theories.
In this survey, we explain the combination of propositional satisfiability and
decision procedures for conjunctions known as DPLL(T), and the alternative
"natural domain" approaches. We also cover quantifiers, Craig interpolants,
polynomial arithmetic, and how SMT solvers are used in automated software
analysis.


title:
Rectifiability of a class of invariant measures with one non-vanishing
  Lyapunov exponent

abstract:
  We study order-preserving C^1-circle diffeomorphisms driven by irrational
rotations with a Diophantine rotation number. We show that there is a non-empty
open set of one-parameter families of such diffeomorphisms where the ergodic
measures of nearly all family members are one-rectifiable, that is, absolutely
continuous with respect to the restriction of the one-dimensional Hausdorff
measure to a countable union of Lipschitz graphs.


title: Type II seesaw supersymmetric neutrino model for $\theta_{13}\neq0$

abstract:
  Using the type II seesaw approach and properties of discrete flavor symmetry
group representations, we build a supersymmetric $A_{4}\times A_{3}$\ neutrino
model with $\theta_{13}\neq0$. After describing the basis of this model--which
is beyond the minimal supersymmetric Standard Model--with a superfield spectrum
containing flavons in $A_{4}\times A_{3}$\ representations, we first generate
the tribimaximal neutrino mixing which is known to be in agreement with the
mixing angles $\theta_{12}$ and $\theta_{23}$. Then, we give the scalar
potential of the theory where the $A_{3}$ discrete subsymmetry is used to avoid
the so-called sequestering problem. We \textrm{next} study the deviation from
the tribimaximal mixing matrix which is produced by perturbing the neutrino
mass matrix with a nontrivial $A_{4}$ singlet. Normal and inverted mass
hierarchies are discussed numerically. We also study the breaking of $A_{4}$\
down to $Z_{3}$\ in the charged lepton sector, and use the branching ratio of
the decay $\tau \rightarrow \mu \mu e$--which is allowed by the residual
symmetry $Z_{3}$--to get estimations on the mass of one of the flavons and the
cutoff scale $\Lambda$ of the model.


title: Network Maximal Correlation

abstract:
  We introduce Network Maximal Correlation (NMC) as a multivariate measure of
nonlinear association among random variables. NMC is defined via an
optimization that infers transformations of variables by maximizing aggregate
inner products between transformed variables. For finite discrete and jointly
Gaussian random variables, we characterize a solution of the NMC optimization
using basis expansion of functions over appropriate basis functions. For finite
discrete variables, we propose an algorithm based on alternating conditional
expectation to determine NMC. Moreover we propose a distributed algorithm to
compute an approximation of NMC for large and dense graphs using graph
partitioning. For finite discrete variables, we show that the probability of
discrepancy greater than any given level between NMC and NMC computed using
empirical distributions decays exponentially fast as the sample size grows. For
jointly Gaussian variables, we show that under some conditions the NMC
optimization is an instance of the Max-Cut problem. We then illustrate an
application of NMC in inference of graphical model for bijective functions of
jointly Gaussian variables. Finally, we show NMC's utility in a data
application of learning nonlinear dependencies among genes in a cancer dataset.


title: Local Operators in Kinetic Wealth Distribution

abstract:
  The statistical mechanics approach to wealth distribution is based on the
conservative kinetic multi-agent model for money exchange, where the local
interaction rule between the agents is analogous to the elastic particle
scattering process. Here, we discuss the role of a class of conservative local
operators, and we show that, depending on the values of their parameters, they
can be used to generate all the relevant distributions. We also show
numerically that in order to generate the power-law tail an heterogeneous risk
aversion model is required. By changing the parameters of these operators one
can also fine tune the resulting distributions in order to provide support for
the emergence of a more egalitarian wealth distribution.


title:
2D Time-frequency interference modelling using stochastic geometry for
  performance evaluation in Low-Power Wide-Area Networks

abstract:
  In wireless networks, interferences between trans- missions are modelled
either in time or frequency domain. In this article, we jointly analyze
interferences in the time- frequency domain using a stochastic geometry model
assuming the total time-frequency resources to be a two-dimensional plane and
transmissions from Internet of Things (IoT) devices time- frequency patterns on
this plane. To evaluate the interference, we quantify the overlap between the
information packets: provided that the overlap is not too strong, the packets
are not necessarily lost due to capture effect. This flexible model can be used
for multiple medium access scenarios and is especially adapted to the random
time-frequency access schemes used in Low-Power Wide-Area Networks (LPWANs). By
characterizing the outage probability and throughput, our approach permits to
evaluate the performance of two representative LPWA technologies
Sigfox{\textsuperscript \textregistered} and LoRaWA{\textsuperscript
\textregistered}.


title:
A study of variable stars in the open cluster NGC 1582 and its
  surrounding field

abstract:
  This paper presents the Charge-Coupled Device time-series photometric
observations of the open cluster NGC 1582 and its surrounding field with
Johnson B, V and R filters by using Nanshan 1m telescope of Xinjiang
Astronomical Observatory. 19 variable stars and 3 variable candidates were
detected in a 45 {\times} 48.75 field around the cluster. 12 of the variable
stars are newly-discovered variable objects. The physical properties,
classifications, and membership of the 22 objects are studied through their
light curves, their positions on the color-magnitude diagram, and with the
archival data from the Naval Observatory Merged Astrometric Dataset. Among
these objects, 5 are eclipsing binary systems, 6 are pulsating variable stars
including one known Delta Scuti star and one newly-discovered RR Lyrae star.
The distance of the RR Lyrae star is estimated to be 7.9 {\pm} 0.3 kpc,
indicates that the star locates far behind the cluster. 4 variable stars are
probable members of the cluster, and 13 of the 22 objects are confirmed to be
field stars.


title:
A splitting method for nonlinear diffusions with nonlocal, nonpotential
  drifts

abstract:
  We prove an existence result for nonlinear diffusion equations in the
presence of a nonlocal density-dependent drift which is not necessarily
potential. The proof is constructive and based on the Helmholtz decomposition
of the drift and a splitting scheme. The splitting scheme combines transport
steps by the divergence-free part of the drift and semi-implicit minimization
steps \`a la Jordan-Kinderlherer-Otto to deal with the potential part.


title:
A Convex Relaxation Approach to Higher-Order Statistical Approaches to
  Signal Recovery

abstract:
  In this work, we investigate an efficient numerical approach for solving
higher order statistical methods for blind and semi-blind signal recovery from
non-ideal channels. We develop numerical algorithms based on convex
optimization relaxation for minimization of higher order statistical cost
functions. The new formulation through convex relaxation overcomes the local
convergence problem of existing gradient descent based algorithms and applies
to several well-known cost functions for effective blind signal recovery
including blind equalization and blind source separation in both
single-input-single-output (SISO) and multi-input-multi-output (MIMO) systems.
We also propose a fourth order pilot based cost function that benefits from
this approach. The simulation results demonstrate that our approach is suitable
for short-length packet data transmission using only a few pilot symbols.


title:
A search for an optical counterpart to the gravitational wave event
  GW151226

abstract:
  We present a search for an electromagnetic counterpart of the gravitational
wave source GW151226. Using the Pan-STARRS1 telescope we mapped out 290 square
degrees in the optical i_ps filter starting 11.5hr after the LIGO information
release and lasting for a further 28 days. The first observations started
49.5hr after the time of the GW151226 detection. We typically reached
sensitivity limits of i_ps = 20.3-20.8 and covered 26.5% of the LIGO
probability skymap. We supplemented this with ATLAS survey data, reaching 31%
of the probability region to shallower depths of m~19. We found 49
extragalactic transients (that are not obviously AGN), including a faint
transient in a galaxy at 7Mpc (a luminous blue variable outburst) plus a
rapidly decaying M-dwarf flare. Spectral classification of 20 other transient
events showed them all to be supernovae. We found an unusual transient,
PS15dpn, with an explosion date temporally coincident with GW151226 which
evolved into a type Ibn supernova. The redshift of the transient is secure at
z=0.1747 +/- 0.0001 and we find it unlikely to be linked, since the luminosity
distance has a negligible probability of being consistent with that of
GW151226. In the 290 square degrees surveyed we therefore do not find a likely
counterpart. However we show that our survey strategy would be sensitive to
NS-NS mergers producing kilonovae at D < 100 Mpc which is promising for future
LIGO/Virgo searches.


title: Kinetic and mean field description of Gibrat's law

abstract:
  We introduce and analyze a linear kinetic model that describes the evolution
of the probability density of the number of firms in a society, in which the
microscopic rate of change obeys to the so-called law of proportional effect
proposed by Gibrat. Despite its apparent simplicity, the possible mean field
limits of the kinetic model are varied. In some cases, the asymptotic limit can
be described by a first-order partial differential equation. In other cases,
the mean field equation is a linear diffusion with a non constant diffusion
coefficient that models also the geometric Brownian motion and can be studied
analytically. In this case, it is shown that the large-time behavior of the
solution is represented, for a large class of initial data, by a lognormal
distribution with constant mean value and variance increasing exponentially in
time at a precise rate. The relationship between the kinetic and the diffusion
models allow to introduce an easy-to- implement expression for computing the
Fourier transform of the lognormal distribution.


title:
V-Net: Fully Convolutional Neural Networks for Volumetric Medical Image
  Segmentation

abstract:
  Convolutional Neural Networks (CNNs) have been recently employed to solve
problems from both the computer vision and medical image analysis fields.
Despite their popularity, most approaches are only able to process 2D images
while most medical data used in clinical practice consists of 3D volumes. In
this work we propose an approach to 3D image segmentation based on a
volumetric, fully convolutional, neural network. Our CNN is trained end-to-end
on MRI volumes depicting prostate, and learns to predict segmentation for the
whole volume at once. We introduce a novel objective function, that we optimise
during training, based on Dice coefficient. In this way we can deal with
situations where there is a strong imbalance between the number of foreground
and background voxels. To cope with the limited number of annotated volumes
available for training, we augment the data applying random non-linear
transformations and histogram matching. We show in our experimental evaluation
that our approach achieves good performances on challenging test data while
requiring only a fraction of the processing time needed by other previous
methods.


title:
All-fiber upconversion high spectral resolution wind lidar using a
  Fabry-Perot interferometer

abstract:
  An all-fiber, micro-pulse and eye-safe high spectral resolution wind lidar
(HSRWL) at 1550nm is proposed and demonstrated by using a pair of upconversion
single-photon detectors and a fiber Fabry-Perot scanning interferometer
(FFP-SI). In order to improve the optical detection efficiency, both the
transmission spectrum and the reflection spectrum of the FFP-SI are used for
spectral analyses of the aerosol backscatter and the reference laser pulse. The
reference signal is tapped from the outgoing laser and served as a zero
velocity indicator. The Doppler shift is retrieved from a frequency response
function Q, which is defined as the ratio of difference of the transmitted
signal and the reflected signal to their sum. Taking advantages of high
signal-to-noise ratio of the detectors and high spectral resolution of the
FFP-SI, the Q spectra of the aerosol backscatter are reconstructed along the
line-of-sight (LOS) of the telescope. By applying a least squares fit procedure
to the measured Q spectra, the center frequencies and the bandwidths are
obtained simultaneously. And then the Doppler shifts are determined relative to
the center frequency of the reference signal. To eliminate the influence of
temperature fluctuations on the FFP-SI, the FFP-SI is cased in a chamber with
temperature stability of 0.001 during the measurement. Continuous LOS wind
observations are carried out on two days at Hefei (31.843 N, 117.265 E), China.
In the meantime, LOS wind measurements from the HSRWL show good agreement with
the results from an ultrasonic wind sensor (Vaisala windcap WMT52). Due to the
computational expensive of the convolution operation of the Q function, an
empirical method is adopted to evaluate the quality of the measurements. The
standard deviation of the wind speed is 0.76 m/s at the 1.8 km. The standard
deviation of the retrieved bandwidth variation is 2.07 MHz at the 1.8 km.


title:
Contact Changes of Sheared Systems: Scaling, Correlations, and
  Mechanisms

abstract:
  We probe the onset and effect of contact changes in 2D soft harmonic particle
packings which are sheared quasistatically under controlled strain. First, we
show that in the majority of cases, the first contact changes correspond to the
creation or breaking of contacts on a single particle, with contact breaking
overwhelmingly likely for low pressures and/or small systems, and contact
making and breaking equally likely for large pressures and in the thermodynamic
limit. The statistics of the corresponding strains are near-Poissonian. The
mean characteristic strains exhibit scaling with the number of particles N and
pressure P, and reveal the existence of finite size effects akin to those seen
for linear response quantities. Second, we show that linear response accurately
predicts the strains of the first contact changes, which allows us to study the
scaling of the characteristic strains of making and breaking contacts
separately. Both of these show finite size scaling, and we formulate scaling
arguments that are consistent with the observed behavior. Third, we probe the
effect of the first contact change on the shear modulus G, and show in detail
how the variation of G remains smooth and bounded in the large system size
limit: even though contact changes occur then at vanishingly small strains,
their cumulative effect, even at a fixed value of the strain, are limited, so
that effectively, linear response remains well-defined. Fourth, we explore
multiple contact changes under shear, and find strong and surprising
correlations between alternating making and breaking events. Fifth, we show
that by making a link with extremal statistics, our data is consistent with a
very slow crossover to self averaging with system size, so that the
thermodynamic limit is reached much more slowly than expected based on finite
size scaling of elastic quantities or contact breaking strains.


title:
Mechanism of Laser/light beam interaction at cellular and tissue level
  and study of the influential factors for the application of low level laser
  therapy

abstract:
  After the discovery of laser therapy it was realized it has useful
application of wound healing and reduce pain, but due to the poor understanding
of the mechanism and dose response this technique remained to be controversial
for therapeutic applications. In order to understand the working and
effectiveness different experiments were performed to determine the laser beam
effect at the cellular and tissue level. This article discusses the mechanism
of beam interaction at tissues and cellular level with different light sources
and dosimetry principles for clinical application of low level laser therapy.
Different application techniques and methods currently in use for clinical
treatment has also been reviewed.


title:
A Powerful Generative Model Using Random Weights for the Deep Image
  Representation

abstract:
  To what extent is the success of deep visualization due to the training?
Could we do deep visualization using untrained, random weight networks? To
address this issue, we explore new and powerful generative models for three
popular deep visualization tasks using untrained, random weight convolutional
neural networks. First we invert representations in feature spaces and
reconstruct images from white noise inputs. The reconstruction quality is
statistically higher than that of the same method applied on well trained
networks with the same architecture. Next we synthesize textures using scaled
correlations of representations in multiple layers and our results are almost
indistinguishable with the original natural texture and the synthesized
textures based on the trained network. Third, by recasting the content of an
image in the style of various artworks, we create artistic images with high
perceptual quality, highly competitive to the prior work of Gatys et al. on
pretrained networks. To our knowledge this is the first demonstration of image
representations using untrained deep neural networks. Our work provides a new
and fascinating tool to study the representation of deep network architecture
and sheds light on new understandings on deep visualization.


title:
A generalized Fellner-Schall method for smoothing parameter estimation
  with application to Tweedie location, scale and shape models

abstract:
  We consider the estimation of smoothing parameters and variance components in
models with a regular log likelihood subject to quadratic penalization of the
model coefficients, via a generalization of the method of Fellner (1986) and
Schall (1991). In particular: (i) we generalize the original method to the case
of penalties that are linear in several smoothing parameters, thereby covering
the important cases of tensor product and adaptive smoothers; (ii) we show why
the method's steps increase the restricted marginal likelihood of the model,
that it tends to converge faster than the EM algorithm, or obvious
accelerations of this, and investigate its relation to Newton optimization;
(iii) we generalize the method to any Fisher regular likelihood. The method
represents a considerable simplification over existing methods of estimating
smoothing parameters in the context of regular likelihoods, without sacrificing
generality: for example, it is only necessary to compute with the same first
and second derivatives of the log-likelihood required for coefficient
estimation, and not with the third or fourth order derivatives required by
alternative approaches. Examples are provided which would have been impossible
or impractical with pre-existing Fellner-Schall methods, along with an example
of a Tweedie location, scale and shape model which would be a challenge for
alternative methods.


title: A Gelfand-Naimark type theorem

abstract:
  Let $X$ be a completely regular space. For a non-vanishing self-adjoint
Banach subalgebra $H$ of $C_B(X)$ which has local units we construct the
spectrum $\mathfrak{sp}(H)$ of $H$ as an open subspace of the Stone-Cech
compactification of $X$ which contains $X$ as a dense subspace. The
construction of $\mathfrak{sp}(H)$ is simple. This enables us to study certain
properties of $\mathfrak{sp}(H)$, among them are various compactness and
connectedness properties. In particular, we find necessary and sufficient
conditions in terms of either $H$ or $X$ under which $\mathfrak{sp}(H)$ is
connected, locally connected and pseudocompact, strongly zero-dimensional,
basically disconnected, extremally disconnected, or an $F$-space.


title:
Ambiguities in one-dimensional phase retrieval from magnitudes of a
  linear canonical transform

abstract:
  Phase retrieval problems occur in a wide range of applications in physics and
engineering. Usually, these problems consist in the recovery of an unknown
signal from the magnitudes of its Fourier transform. In some applications,
however, the given intensity arises from a different transformation such as the
Fresnel or fractional Fourier transform. More generally, we here consider the
phase retrieval of an unknown signal from the magnitudes of an arbitrary linear
canonical transform. Using the close relation between the Fourier and the
linear canonical transform, we investigate the arising ambiguities of these
phase retrieval problems and transfer the well-known characterizations of the
solution sets from the classical Fourier phase retrieval problem to the new
setting.


title:
A Unified Framework for Analyzing Closed Queueing Networks in Bike
  Sharing Systems

abstract:
  During the last decade bike sharing systems have emerged as a public
transport mode in urban short trips in more than 500 major cities around the
world. For the mobility service mode, many challenges from its operations are
not well addressed yet, for example, how to develop the bike sharing systems to
be able to effectively satisfy the fluctuating demands both for bikes and for
vacant lockers. To this end, it is a key to give performance analysis of the
bike sharing systems. This paper first describes a large-scale bike sharing
system. Then the bike sharing system is abstracted as a closed queueing network
with multi-class customers, where the virtual customers and the virtual nodes
are set up, and the service rates as well as the relative arrival rates are
established. Finally, this paper gives a product-form solution to the steady
state joint probabilities of queue lengths, and gives performance analysis of
the bike sharing system. Therefore, this paper provides a unified framework for
analyzing closed queueing networks in the study of bike sharing systems. We
hope the methodology and results of this paper can be applicable in the study
of more general bike sharing systems.


title: Holomorphic maps from the complex unit ball to Type IV classical domains

abstract:
  We prove rigidity results for holomorphic proper maps from the complex unit
ball $\mathbb{B}^n$ to the Type IV bounded symmetric domain $D^{IV}_m$ where $n
\geq 4, n+1\leq m \leq 2n-3$. In addition, a classification result is
established when $m=n+1.$


title: The non-Hermitian Swanson model with a time-dependent metric

abstract:
  We provide further non-trivial solutions to the recently proposed
time-dependent Dyson and quasi-Hermiticity relation. Here we solve them for the
generalized version of the non-Hermitian Swanson Hamiltonian with
time-dependent coefficients. We construct time-dependent solutions by employing
the Lewis-Riesenfeld method of invariants and discuss concrete physical
applications of our results.


title: Experimental aspects of the tachyon hypothesis

abstract:
  This note is aimed at an introductory presentation of experimental
characteristics of charged tachyons, deduced under the assumption that the
tachyons possess standard electromagnetic interactions. In particular,
Cherenkov radiation by tachyons, their ionization loss in tracking devices and
the bremsstrahlung loss in electromagnetic calorimeters are considered.


title: ASAGA: Asynchronous Parallel SAGA

abstract:
  We describe ASAGA, an asynchronous parallel version of the incremental
gradient algorithm SAGA that enjoys fast linear convergence rates. Through a
novel perspective, we revisit and clarify a subtle but important technical
issue present in a large fraction of the recent convergence rate proofs for
asynchronous parallel optimization algorithms, and propose a simplification of
the recently introduced "perturbed iterate" framework that resolves it. We
thereby prove that ASAGA can obtain a theoretical linear speedup on multi-core
systems even without sparsity assumptions. We present results of an
implementation on a 40-core architecture illustrating the practical speedup as
well as the hardware overhead.


title: Spectral Analysis for Perturbed Operators on Carnot Groups

abstract:
  Let $\G$ be a Carnot group of homogeneous dimension $M$ and $\Delta$ its
horizontal sublaplacian. For $\alpha\in(0,M)$ we show that operators of the
form $H_\alpha:=(-\Delta)^\alpha+V$ have no singular spectrum, under generous
assumptions on the multiplication operator $V$. The proof is based on
commutator methods and Hardy inequalities.


title:
Deep SDSS Optical Spectroscopy of Distant Halo Stars. III. Chemical
  analysis of extremely metal-poor stars

abstract:
  We present the results of an analysis for 107 extremely metal-poor (EMP)
stars with metallicities less than [Fe/H] = -3.0, identified from
medium-resolution spectra in SDSS. We follow a methodology based on comparisons
of the observed spectra with synthetic spectra. The abundances of Fe, Ca, and
Mg are determined by fitting spectral regions dominated by lines of each
element. In addition, we present a technique to determine upper limits for
elements whose features are not detected in a given spectrum. We also analyse
our sample with the SEGUE Stellar Parameter Pipeline, in order to obtain
additional determinations of the atmospheric parameters, iron and alpha-element
abundances, to compare with ours, and to infer [C/Fe] ratios. We find that, in
these moderate to low signal-to-noise and medium-resolution spectra in this
metallicity regime, Ca is usually the only element that exhibits lines that are
sufficiently strong to reliably measure its abundance. Fe and Mg exhibit weaker
features that, in most cases, only provide upper limits. We measure [Ca/Fe] and
[Mg/Fe] for EMP stars in the SDSS spectra, and conclude that most of the stars
exhibit the usual level of enhancement for {\alpha}-elements, ~ +0.4, although
a number of stars for which only [Fe/H] upper limits could be estimated point
to higher [{\alpha}/Fe] ratios. We also find that 26 % of the stars in our
sample can be classified as carbon-enhanced metal-poor (CEMP) stars, and that
the frequency of CEMP stars also increases with decreasing metallicity, as has
been reported for previous samples. We identity a rare, bright (g = 11.90) EMP
star, SDSS J134144.61+474128.6, with [Fe/H] = -3.27, [C/Fe] = +0.95, and
elevated magnesium ([Mg/Fe] = +0.62), an abundance pattern typical of CEMP-no
stars.


title:
Combined role of molecular diffusion, mean streaming and helicity in the
  eddy diffusivity of short-correlated random flows

abstract:
  We analytically investigate the effective-diffusivity tensor of a tracer
particle in a fluid flow endowed with a short correlation time. By means of
functional calculus and a multiscale expansion, we write down the main
contributions to the eddy diffusivity due to each single physical effect and to
their interplays. Namely, besides molecular diffusivity and a constant uniform
mean streaming, we take into account the possibility for the (incompressible,
Gaussian, stationary, homogeneous, isotropic) turbulent fluctuations to break
parity invariance. With respect to the classical turbulence-driven diffusivity
amplification for delta-correlated flows, we find that the presence of a short
temporal correlation induces a diminution even when coupled with such effects,
with two principal exceptions. Notably, the diffusivity is --- perturbatively
--- enlarged not only by the helical contribution itself, but also by the
interference between molecular diffusion and mean flow.


title:
Spin dynamics in Kapitza-Dirac scattering of electrons from bichromatic
  laser fields

abstract:
  Kapitza-Dirac scattering of nonrelativistic electrons from counterpropagating
bichromatic laser waves of linear polarization is studied. The focus lies on
the electronic spin dynamics in the Bragg regime when the laser fields possess
a frequency ratio of two. To this end, the time-dependent Pauli equation is
solved numerically, both in coordinate space and momentum space. Our numerical
results are corroborated by analytical derivations. We demonstrate that, for
certain incident electron momenta, the scattering crucially relies on the
electron spin which undergoes characteristic Rabi-like oscillations. A
parameter regime is identified where the Rabi oscillations reach maximum
amplitude. We also briefly discuss spin-dependent Kapitza-Dirac scattering of
protons.


title: On The Rationality Of The Spectrum

abstract:
  Let $\Omega \subset \mathbb{R}$ be a compact set with measure $1$. If there
exists a subset $\Lambda \subset \mathbb{R}$ such that the set of exponential
functions $E_{\Lambda}:=\{e_\lambda(x) = e^{2\pi i \lambda x}|_\Omega :\lambda
\in \Lambda\}$ is an orthonormal basis for $L^2(\Omega)$, then $\Lambda$ is
called a spectrum for the set $\Omega$. A set $\Omega$ is said to tile
$\mathbb{R}$ if there exists a set $\mathcal T$ such that $\Omega + \mathcal T
= \mathbb{R}$. A conjecture of Fuglede suggests that Spectra and Tiling sets
are related. Lagarias and Wang \cite {LW1} proved that Tiling sets are always
periodic and are rational. That any spectrum is also a periodic set was proved
in \cite {BM1}, \cite {IK}. In this paper, we give some partial results to
support the rationality of the spectrum.


title: The B and Be States of the Star EM Cepheus

abstract:
  We present eleven years of high-resolution, spectroscopic observations for
the star EM~Cep. EM~Cep switches between B and Be star states, as revealed by
the level of H$\alpha$ emission, but spends most of its time in the B~star
state. EM~Cep has been considered to be an eclipsing, near contact binary of
nearly equal-massed B stars in order to reproduce regular photometric
variations; however, this model is problematic due to the lack of any observed
Doppler shift in the spectrum. Our observations confirm that there are no
apparent Doppler shifts in the wide spectral lines H$\alpha$ and HeI~6678 in
either the B or Be star states.The profiles of HeI~6678 typically exhibited a
filled-in absorption core, but we detected weak emission in this line during
the highest Be state. Given the lack of observed Doppler shifts, we model
EM~Cep as an isolated Be star with a variable circumstellar disk. We can
reproduce the observed H$\alpha$ emission profiles over the eleven year period
reasonably well with disk masses on the order of $3$ to
$10\times\,10^{-11}\;M_*$ in the Be state with the circumstellar disk seen at
an inclination of $78^{\circ}$ to the line of sight. From a disk ejection
episode in 2014, we estimate a mass loss rate of $\approx\,3\times 10^{-9}\;\rm
M_{\odot}\,yr^{-1}$. The derived disk density parameters are typical of those
found for the classical Be stars. We therefore suggest that the EM~Cep is a
classical Be star and that its photometric variations are the result of
$\beta\;$Cep or non-radial pulsations.


title: Note on level r consensus

abstract:
  We show that the hierarchy of level $r$ consensus partially collapses. In
particular, any profile $\pi\in \mathcal{P}$ that exhibits consensus of level
$(K-1)!$ around $\succ_0$ in fact exhibits consensus of level $1$ around
$\succ_0$.


title: Correlation steering in the angularly multimode Raman atomic memory

abstract:
  We present the possibility of steering the direction of correlations between
the off-resonant Raman scattered photons from the angularly multimode atomic
memory based on warm rubidium vapors. Using acousto-optic deflectors (AOD)
driven by different modulation frequencies we experimentally change the angle
of incidence of the laser beams on the atomic ensemble. Performing correlations
measurements for various deflection angles we verify that we can choose the
anti-Stokes light propagation direction independently of the correlated Stokes
scattered light in the continuous way. As a result we can select the spatial
mode of photons retrieved from the memory, which may be important for future
development of quantum information processing.


title:
Quantum dynamics of optical phonons generated by optical excitation of a
  quantum dot

abstract:
  The study of the fundamental properties of phonons is crucial to understand
their role in applica- tions in quantum information science, where the active
use of phonons is currently highly debated. A genuine quantum phenomenon
associated with the fluctuation properties of phonons is squeezing, which is
achieved when the fluctuations of a certain variable drop below their
respective vacuum value. We consider a semiconductor quantum dot in which the
exciton is coupled to phonons. We review the fluctuation properties of the
phonons, which are generated by optical manipulation of the quantum dot, in the
limiting case of ultra short pulses. Then we discuss the phonon properties for
an excitation with finite pulses. Within a generating function formalism we
calculate the corre- sponding fluctuation properties of the phonons and show
that phonon squeezing can be achieved by the optical manipulation of the
quantum dot exciton for certain conditions even for a single pulse excitation
where neither for short nor for long pulses squeezing occurs. To explain the
occurrence of squeezing we employ a Wigner function picture providing a
detailed understanding of the induced quantum dynamics.


title: Nonparametric Analysis of Random Utility Models

abstract:
  This paper develops and implements a nonparametric test of Random Utility
Models. The motivating application is to test the null hypothesis that a sample
of cross-sectional demand distributions was generated by a population of
rational consumers. We test a necessary and sufficient condition for this that
does not rely on any restriction on unobserved heterogeneity or the number of
goods. We also propose and implement a control function approach to account for
endogenous expenditure. An econometric result of independent interest is a test
for linear inequality constraints when these are represented as the vertices of
a polyhedron rather than its faces. An empirical application to the U.K.
Household Expenditure Survey illustrates computational feasibility of the
method in demand problems with 5 goods.


title: Understanding Probabilistic Sparse Gaussian Process Approximations

abstract:
  Good sparse approximations are essential for practical inference in Gaussian
Processes as the computational cost of exact methods is prohibitive for large
datasets. The Fully Independent Training Conditional (FITC) and the Variational
Free Energy (VFE) approximations are two recent popular methods. Despite
superficial similarities, these approximations have surprisingly different
theoretical properties and behave differently in practice. We thoroughly
investigate the two methods for regression both analytically and through
illustrative examples, and draw conclusions to guide practical application.


title:
Quantum dynamics of trapped ions in a dynamic field gradient using
  dressed states

abstract:
  Novel ion traps that provide either a static or a dynamic magnetic gradient
field allow for the use of radio frequency (rf) radiation for coupling internal
and motional states of ions, which is essential for conditional quantum logic.
We show that the coupling mechanism in the presence of a dynamic gradient is
the same, in a dressed state basis, as in the case of a static gradient. Then,
it is shown how demanding experimental requirements arising when using a
dynamic gradient could be overcome. Thus, using dressed states in a dynamic
gradient field could decisively reduce experimental complexity on the route
towards a scalable device for quantum information science based on rf-driven
trapped ions.


title: Remarks on the degree growth of birational transformations

abstract:
  We look at sequences of positive integers that can be realized as degree
sequences of iterates of rational dominant maps of smooth projective varieties
over arbitrary fields. New constraints on the degree growth of endomorphisms of
the affine space and examples of degree sequences are displayed. We also show
that the set of all degree sequences of rational maps is countable; this
generalizes a result of Bonifant and Fornaess.


title:
The impact of the Star Formation Histories on the SFR-M$_{*}$ relation
  at z$\ge$2

abstract:
  In this paper we investigate the impact of different star formation histories
(SFHs) on the relation between stellar mass M$_{*}$ and star formation rate
(SFR) using a sample of galaxies with reliable spectroscopic redshift zspec>2
drawn from the VIMOS Ultra-Deep Survey (VUDS). We produce an extensive database
of dusty model galaxies, calculated starting from the new library of single
stellar population (SSPs) models presented in Cassara' et al. 2013 and weighted
by a set of 28 different SFHs based on the Schmidt function, and characterized
by different ratios of the gas infall time scale $\tau_{infall}$ to the star
formation efficiency $\nu$. The treatment of dust extinction and re-emission
has been carried out by means of the radiative transfer calculation. The
spectral energy distribution (SED) fitting technique is performed by using
GOSSIP+, a tool able to combine both photometric and spectroscopic information
to extract the best value of the physical quantities of interest, and to
consider the Intergalactic Medium (IGM) attenuation as a free parameter. We
find that the main contribution to the scatter observed in the $SFR-M_{*}$
plane is the possibility of choosing between different families of SFHs in the
SED fitting procedure, while the redshift range plays a minor role. The
majority of the galaxies, at all cosmic times, are best-fit by models with SFHs
characterized by a high $\tau_{\rm infall}/\nu$ ratio. We discuss the
reliability of the presence of a small percentage of dusty and highly star
forming galaxies, in the light of their detection in the FIR.


title: Global transport in a nonautonomous standard map

abstract:
  A non-autonomous version of the standard map with a periodic variation of the
parameter is introduced and studied. Symmetry properties in the variables and
parameters of the map are found and used to find relations between rotation
numbers of invariant sets of the autonomous realization of the period-two case
of the map. The role of the nonautonomous dynamics on period-one orbits,
stability and bifurcation is studied. The critical boundaries for the global
transport and the destruction of invariant circles with fixed rotation number
are studied in detail using direct computation and a continuation method. In
the case of global transport, the critical boundary has a particular
symmetrical horn shape. The results are contrasted with similar calculations
found in the literature.


title: Inverting the cut-tree transform

abstract:
  We consider fragmentations of an R-tree $T$ driven by cuts arriving according
to a Poisson process on $T \times [0, \infty)$, where the first co-ordinate
specifies the location of the cut and the second the time at which it occurs.
The genealogy of such a fragmentation is encoded by the so-called cut-tree,
which was introduced by Bertoin and Miermont for a fragmentation of the
Brownian continuum random tree. The cut-tree was generalised by Dieuleveut to a
fragmentation of the $\alpha$-stable trees, $\alpha \in (1, 2)$, and by Broutin
and Wang to the inhomogeneous continuum random trees of Aldous and Pitman.
Remarkably, in all of these cases, the law of the cut-tree is the same as that
of the original R-tree. In this paper, we develop a clean general framework for
the study of cut-trees of R-trees. We then focus particularly on the problem of
reconstruction: how to recover the original R-tree from its cut-tree. This has
been studied in the setting of the Brownian CRT by Broutin and Wang, where they
prove that it is possible to reconstruct the original tree in distribution. We
describe an enrichment of the cut-tree transformation, which endows the cut
tree with information we call a consistent collection of routings. We show this
procedure is well-defined under minimal conditions on the R-trees. We then show
that, for the case of the Brownian CRT and the $\alpha$-stable trees with
$\alpha \in (1, 2)$, the original tree and the Poisson process of cuts thereon
can both be almost surely reconstructed from the enriched cut-trees. For the
latter results, our methods make essential use of the self-similarity and
re-rooting invariance of these trees.


title: Sub-Poisson-Binomial Light

abstract:
  We introduce the general parameter Q_PB that provides an experimentally
accessible nonclassicality measure for light. The parameter is quantified by
the click statistics obtained from on-off detectors in a general multiplexing
detection setup. Sub-Poisson-binomial statistics, observed by Q_PB<0, indicates
that a given state of light is nonclassical. Our new parameter replaces the
binomial parameter Q_B for more general cases, where any unbalance among the
multiplexed modes is allowed, thus enabling the use of arbitrary multiplexing
schemes. The significance of the parameter Q_PB is theoretically examined in a
measurement setup that only consists of a ring resonator and a single on-off
detector. The proposed setup exploits minimal experimental resources and is
geared towards a fully integrated quantum nanophotonic circuit. The results
show that nonclassical features remain noticeable even in the presence of
significant losses, rendering the new nonclassicality test more practical and
flexible to be used in various nanophotonic platforms.


title:
Multi-wavelength properties of IGR J05007-7047 (LXP 38.55) and
  identification as a Be X-ray binary pulsar in the LMC

abstract:
  We report on the results of a $\sim$40 d multi-wavelength monitoring of the
Be X-ray binary system IGR J05007-7047 (LXP 38.55). During that period the
system was monitored in the X-rays using the Swift telescope and in the optical
with multiple instruments. When the X-ray luminosity exceeded $10^{36}$ erg/s
we triggered an XMM-Newton ToO observation. Timing analysis of the photon
events collected during the XMM-Newton observation reveals coherent X-ray
pulsations with a period of 38.551(3) s (1 {\sigma}), making it the 17$^{th}$
known high-mass X-ray binary pulsar in the LMC. During the outburst, the X-ray
spectrum is fitted best with a model composed of an absorbed power law ($\Gamma
=0.63$) plus a high-temperature black-body (kT $\sim$ 2 keV) component. By
analysing $\sim$12 yr of available OGLE optical data we derived a 30.776(5) d
optical period, confirming the previously reported X-ray period of the system
as its orbital period. During our X-ray monitoring the system showed limited
optical variability while its IR flux varied in phase with the X-ray
luminosity, which implies the presence of a disk-like component adding cooler
light to the spectral energy distribution of the system.


title: The prescribed mean curvature equation in weakly regular domains

abstract:
  We show that the characterization of existence and uniqueness up to vertical
translations of solutions to the prescribed mean curvature equation, originally
proved by Giusti in the smooth case, holds true for domains satisfying very
mild regularity assumptions. Our results apply in particular to the
non-parametric solutions of the capillary problem for perfectly wetting fluids
in zero gravity. Among the essential tools used in the proofs, we mention a
\textit{generalized Gauss-Green theorem} based on the construction of the weak
normal trace of a vector field with bounded divergence, in the spirit of
classical results due to Anzellotti, and a \textit{weak Young's law} for
$(\Lambda,r_{0})$-minimizers of the perimeter.


title:
Trapping and manipulation of individual nanoparticles in a planar Paul
  trap

abstract:
  Visualization and manipulation of nanoscale matter is one of the main and
current challenges in nanosciences. To this aim, different techniques have been
recently developed to non-invasively trap and manipulate nano-specimens, like
nanoparticles or molecules. However, operating in air or vacuum still remains
very challenging since most approaches are limited to a liquid environment. In
this letter, we design and characterize a planar Paul trap optimized to trap
and manipulate individual charged nanoparticles. This configuration offers
competitive capabilities to manipulate nano-specimens in air or vacuum
including in-plane integration, high trap confinement along with dynamical trap
reconfiguration.


title: Bind: a Partitioned Global Workflow Parallel Programming Model

abstract:
  High Performance Computing is notorious for its long and expensive software
development cycle. To address this challenge, we present Bind: a "partitioned
global workflow" parallel programming model for C++ applications that enables
quick prototyping and agile development cycles for high performance computing
software targeting heterogeneous distributed many-core architectures. We
present applications of Bind to Linear Algebra and MapReduce algorithms
alongside with performance results.


title:
Spectral stability of traveling fronts for reaction diffusion-degenerate
  Fisher-KPP equations

abstract:
  This paper establishes the spectral stability in exponentially weighted
spaces of smooth traveling monotone fronts for reaction diffusion equations of
Fisher-KPP type with nonlinear degenerate diffusion coefficient. It is assumed
that the former is degenerate, that is, it vanishes at zero, which is one of
the equilibrium points of the reaction. A parabolic regularization technique is
introduced in order to locate a subset of the compression spectrum of the
linearized operator around the wave, whereas the point spectrum is proved to be
stable with the use of energy estimates. Detailed asymptotic decay estimates of
solutions to spectral equations are required in order to close the energy
estimates. It is shown that all fronts traveling with speed above a threshold
value are spectrally stable in an appropriately chosen exponentially weighted
$L^2$-space.


title: Generalized Soft-and-Hard/DB Boundary

abstract:
  A novel class of boundary conditions is introduced as a generalization of the
previously defined class of soft-and-hard/DB (SHDB) boundary conditions. It is
shown that the conditions for the generalized soft-and-hard/DB (GSHDB) boundary
arise most naturally in a simple and straightforward manner by applying
four-dimensional differential-form and dyadic formalism. At a given boundary
surface, the GSHDB conditions are governed by two one-forms. In terms of
Gibbsian 3D vector and dyadic algebra the GSHDB conditions are defined in terms
of two vectors tangential to the boundary surface and two scalars. Considering
plane-wave reflection from the GSHDB boundary, for two eigenpolarizations, the
GSHDB boundary can be replaced by the PEC or PMC boundary. Special attention is
paid to the problem of plane waves matched to the GSHDB boundary, defined by a
2D dispersion equation for the wave vector, making the reflection dyadic
indeterminate. Examples of dispersion curves for various chosen parameters of
the GSHDB boundary are given. Conditions for a possible medium whose interface
acts as a GSHDB boundary are discussed.


title:
Searches for heavy diboson resonances in $pp$ collisions at
  $\sqrt{s}=13$ TeV with the ATLAS detector

abstract:
  Searches for new heavy resonances decaying to $WW$, $WZ$, and $ZZ$ bosons are
presented, using a data sample corresponding to 3.2 fb$^{-1}$ of $pp$
collisions at $\sqrt{s}=13$ TeV collected with the ATLAS detector at the CERN
Large Hadron Collider. Analyses selecting $\nu\nu qq$, $\ell\nu qq$, $\ell\ell
qq$ and $qqqq$ final states are combined, searching for a narrow-width
resonance with mass between 500 and 3000 GeV. The discriminating variable is
either an invariant mass or a transverse mass. No significant deviations from
the Standard Model predictions are observed. Three benchmark models are tested:
a model predicting the existence of a new heavy scalar singlet, a simplified
model predicting a heavy vector-boson triplet, and a bulk Randall-Sundrum model
with a heavy spin-2 graviton. Cross-section limits are set at the 95%
confidence level and are compared to theoretical cross-section predictions for
a variety of models. The data exclude a scalar singlet with mass below 2650
GeV, a heavy vector-boson triplet with mass below 2600 GeV, and a graviton with
mass below 1100 GeV. These results significantly extend the previous limits set
using $pp$ collisions at $\sqrt{s}=8$ TeV.


title:
d2, d3, and d4 M3C2 Transition Metal Carbides (MXenes) as Catalysts for
  CO2 Conversion into Hydrocarbon Fuels: A Mechanistic and Pre-dictive DFT
  Study

abstract:
  The functioning of 2D d2, d3, and d4 transition metal carbides as CO2
conversion catalysts has been proved by well resolved density functional theory
(DFT) and DFT+U theoretical calculations. Whilst MXenes from the d2 series (M =
Ti, Zr, and Hf) have demonstrated active behaviors for the capture of CO2, the
V3C2, Nb3C2, Cr3C2, and Mo3C2 materials exhibit the most promising results for
their application in the selective CO2 conversion into CH4, with limiting
reaction energies of 1.55, 1.75, 0.69, and 1.24 eV, respectively, at DFT+U
computational level plus explicit DFT-D3 dispersion corrections, and specially
highlighting the role of Cr3C2 due to its theoretically predicted low over
potential. Moreover, important features have been predicted during the first
hydrogenation step towards the formation of the OCHO and HOCO radical species,
exhibiting spontaneous reaction energies in the OCHO obtaining for such
promising carbides from the d3 and d4 groups. Our re-sults provide novel
insights in the computer-aided searching of high performance catalysts and the
understanding of reaction mech-anisms for CO2. Finally, it is hypothesized that
the capture of CO2 along the early step of the reaction is spontaneously
produced without pass from a physisorbed state, being the strength of such
capture larger than the computed binding energies for the chemi-sorption of
H2O, offering encouraging perspectives for the experimental testing of our
materials in water environment


title: Learning Word Sense Embeddings from Word Sense Definitions

abstract:
  Word embeddings play a significant role in many modern NLP systems. Since
learning one representation per word is problematic for polysemous words and
homonymous words, researchers propose to use one embedding per word sense.
Their approaches mainly train word sense embeddings on a corpus. In this paper,
we propose to use word sense definitions to learn one embedding per word sense.
Experimental results on word similarity tasks and a word sense disambiguation
task show that word sense embeddings produced by our approach are of high
quality.


title: Sketched Floor plans versus SLAM maps: A Comparison

abstract:
  Maps --- specifically floor plans --- are useful for a variety of tasks from
arranging furniture to designating conceptual or functional spaces (e.g.,
kitchen, walkway). We present a simple algorithm for quickly laying a floor
plan (or other conceptual map) onto a SLAM map, creating a one-to-one mapping
between them. Our goal was to enable using a floor plan (or other hand-drawn or
annotated map) in robotic applications instead of the typical SLAM map created
by the robot. We look at two use cases, specifying "no-go" regions within a
room and locating objects within a scanned room. Although a user study showed
no statistical difference between the two types of maps in terms of performance
on this spatial memory task, we argue that floor plans are closer to the mental
maps people would naturally draw to characterize spaces.


title:
Energy versus centrality dependence of the jet quenching parameter $\hat
  q$ at RHIC and LHC: a new puzzle?

abstract:
  The central goal of jet quenching studies in high-energy nuclear collisions
is the characterization of those QCD medium properties that are accessible by
these probes. Most of the discussion in the last years has been focused on the
determination of the jet quenching parameter, $\hat q$. We present here an
extraction of this parameter using data of inclusive particle suppression at
RHIC and LHC energies for different centralities. Our approach consists of
fitting a $K$ factor that quantifies the departure of this parameter from an
ideal estimate, $K\equiv \hat q/(2\epsilon^{3/4})$, where $\hat q$ is
determined by the local medium quantities as provided by hydrodynamical
calculations. We find that this $K$ factor is larger at RHIC than at the LHC,
as obtained already in previous analyses, but, surprisingly, it is almost
independent of the centrality of the collision. Taken at face value, the $K$
factor would not depend on the local properties of the medium as energy density
or temperature, but on global collision quantities such as the center of mass
energy. This is a very intriguing, unexpected possibility for which we cannot
yet provide a clear interpretation. We also comment on the limitations of the
formalism that may affect this conclusion.


title: Optimization Methods for Large-Scale Machine Learning

abstract:
  This paper provides a review and commentary on the past, present, and future
of numerical optimization algorithms in the context of machine learning
applications. Through case studies on text classification and the training of
deep neural networks, we discuss how optimization problems arise in machine
learning and what makes them challenging. A major theme of our study is that
large-scale machine learning represents a distinctive setting in which the
stochastic gradient (SG) method has traditionally played a central role while
conventional gradient-based nonlinear optimization techniques typically falter.
Based on this viewpoint, we present a comprehensive theory of a
straightforward, yet versatile SG algorithm, discuss its practical behavior,
and highlight opportunities for designing algorithms with improved performance.
This leads to a discussion about the next generation of optimization methods
for large-scale machine learning, including an investigation of two main
streams of research on techniques that diminish noise in the stochastic
directions and methods that make use of second-order derivative approximations.


title:
Few-qubit quantum-classical simulation of strongly correlated lattice
  fermions

abstract:
  We study a proof-of-principle example of the recently proposed hybrid
quantum-classical simulation of strongly correlated fermion models in the
thermodynamic limit. In a "two-site" dynamical mean-field theory (DMFT)
approach we reduce the Hubbard model to an effective impurity model subject to
self-consistency conditions. The resulting minimal two-site representation of
the non-linear hybrid setup involves four qubits implementing the impurity
problem, plus an ancilla qubit on which all measurements are performed. We
outline a possible implementation with superconducting circuits feasible with
near-future technology.


title:
Recent Tectonic Activity on Pluto Driven by Phase Changes in the Ice
  Shell

abstract:
  The New Horizons spacecraft has found evidence for geologic activity on the
surface of Pluto, including extensional tectonic deformation of its water ice
bedrock (see Moore et al., 2016). One mechanism that could drive extensional
tectonic activity is global surface expansion due to the partial freezing of an
ocean. We use updated physical properties for Pluto and simulate its thermal
evolution to understand the survival of a possible subsurface ocean. For
thermal conductivities of rock less than 3 W m$^{-1}$ K$^{-1}$, an ocean forms
and at least partially freezes, leading to recent extensional stresses in the
ice shell. In scenarios where the ocean freezes and the ice shell is thicker
than $260$ km, ice II forms and causes global volume contraction. Since there
is no evidence for recent compressional tectonic features, we argue that ice II
has not formed and that Pluto's ocean has likely survived to present day.


title:
Temperature-dependent excitonic photoluminescence Excited by Two-Photon
  Absorption in Perovskite CsPbBr3 Quantum Dots

abstract:
  Recently lead halide nanocrystals (quantum dots) have been reported with
potential for photovoltaic and optoelectronic applications due to their
excellent luminescent properties. Herein excitonic photoluminescence (PL)
excited by two-photon absorption in perovskite CsPbBr3 quantum dots (QDs) have
been studied across a broad temperature range from 80K to 380K. Two-photon
absorption has been investigated with absorption coefficient up to 0.085 cm/GW
at room temperature. Moreover, the photoluminescence excited by two-photon
absorption shows a linear blue-shift (0.25meV/K) below temperature of ~220K and
turned steady with fluctuation below 1nm (4.4meV) for higher temperature up to
380K. These phenomena are distinctly different from general red-shift of
semiconductor and can be explained by the competition between lattice expansion
and electron-phonon couplling.Our results reveal the strong nonlinear
absorption and temperature-independent chromaticity in a large temperature
range from 220K to 380K in the CsPbX3 QDs, which will offer new opportunities
in nonlinear photonics, light-harvesting and light-emitting devices.


title:
The nucleosynthetic history of elements in the Galactic disk: [X/Fe] -
  age relations from high-precision spectroscopy

abstract:
  Context: The chemical composition of stars is intimately linked to the Galaxy
formation and evolution. Aims: We aim to trace the chemical evolution of the
Galactic disk through the inspection of the [X/Fe]-age relations of 24 species
from C to Eu. Methods: Using high-resolution and high-signal-to-noise UVES
spectra of nine solar twins, we obtained precise estimates of stellar ages and
chemical abundances. These determinations have been integrated with additional
accurate age and abundance determinations from recent spectroscopic studies of
solar twins existing in the literature, comprising superb abundances with
0.01~dex precision. Based on this data set, we outlined the [X/Fe]-age
relations over a time interval of 10~Gyr. Results: We present the [X/Fe] - age
relations for 24 elements (C, O, Na, Mg, Al, Si, S, K, Ca, Sc, Ti, V, Cr, Mn,
Co, Ni, Cu, Zn, Y, Ba, La, Ce, Nd, and Eu). Each different class of elements
showed distinct evolution with time that relies on the different
characteristics, rates and timescales of the nucleosynthesis' sites from which
they are produced. The $\alpha$-elements are characterised by a [X/Fe]
decrement as time goes on. Strikingly, an opposite behaviour is observed for
Ca. The iron-peak elements show an early [X/Fe] increase followed by a decrease
towards the youngest stars. The [X/Fe] for the n-capture elements decrease with
age. We also found that both [Mg/Y] and [Al/Y] are precise stellar clocks, with
[Al/Y] showing the steepest dependence with age. Conslusions: Knowledge of the
[X/Fe]-age relations is a gold mine from which we can achieve a great
understanding about the processes that governed the formation and evolution of
the Milky Way. Through the reverse engineering of these relations we will be
able to put strong constraints on the nature of the stellar formation history,
the SNe rates, the stellar yields, and the variety of the SNe progenitors.


title:
The internal composition of proto-neutron stars under strong magnetic
  fields

abstract:
  In this work, we study the effects of magnetic fields and rotation on the
structure and composition of proto-neutron stars (PNS's). A hadronic chiral
SU(3) model is applied to cold neutron stars (NS) and proto-neutron stars with
trapped neutrinos and at fixed entropy per baryon. We obtain general
relativistic solutions for neutron and proto-neutron stars endowed with a
poloidal magnetic field by solving Einstein-Maxwell field equations in a
self-consistent way. As the neutrino chemical potential decreases in value over
time, this alters the chemical equilibrium and the composition inside the star,
leading to a change in the structure and in the particle population of these
objects. We find that the magnetic field deforms the star and significantly
alters the number of trapped neutrinos in the stellar interior, together with
strangeness content and temperature in each evolution stage.


title:
Fractional derivative defined by non-singular kernels to capture
  anomalous relaxation and diffusion

abstract:
  Anomalous relaxation and diffusion processes have been widely characterized
by fractional derivative models, where the definition of the fractional-order
derivative remains a historical debate due to the singular memory kernel that
challenges numerical calculations. This study first explores physical
properties of relaxation and diffusion models where the fractional derivative
was defined recently using an exponential kernel. Analytical analysis shows
that the fractional derivative model with an exponential kernel cannot
characterize non-exponential dynamics well-documented in anomalous relaxation
and diffusion. A legitimate extension of the previous fractional derivative is
then proposed by replacing the exponential kernel with a stretched exponential
kernel. Numerical tests show that the fractional derivative model with the
stretched exponential kernel can describe a much wider range of anomalous
diffusion than the exponential kernel, implying the potential applicability of
the new fractional derivative in quantifying real-world, anomalous relaxation
and diffusion processes.


title: Large Range Manipulation of Exciton Species in Monolayer WS2

abstract:
  Unconventional emissions from exciton and trion in monolayer WS2 are studied
by photoexcitation. Excited by 532nm laser beam, the carrier species in the
monolayer WS2 are affected by the excess electrons escaping from
photoionization of donor impurity, the concentration of which varies with
different locations of the sample. Simply increasing the excitation power at
room temperature, the excess electron and thus the intensity ratio of excited
trion and exciton can be continuously tuned over a large range from 0.1 to 7.7.
Furthermore, this intensity ratio can also be manipulated by varying
temperature. However, in this way the resonance energy of the exciton and trion
show red-shifts with increasing temperature due to electron-phonon coupling.
The binding energy of the trion is determined to be ~23meV and independent to
temperature, indicating strong Coulomb interaction of carriers in such 2D
materials.