title:
Using a Distributional Semantic Vector Space with a Knowledge Base for
  Reasoning in Uncertain Conditions

abstract:
  The inherent inflexibility and incompleteness of commonsense knowledge bases
(KB) has limited their usefulness. We describe a system called Displacer for
performing KB queries extended with the analogical capabilities of the word2vec
distributional semantic vector space (DSVS). This allows the system to answer
queries with information which was not contained in the original KB in any
form. By performing analogous queries on semantically related terms and mapping
their answers back into the context of the original query using displacement
vectors, we are able to give approximate answers to many questions which, if
posed to the KB alone, would return no results.
  We also show how the hand-curated knowledge in a KB can be used to increase
the accuracy of a DSVS in solving analogy problems. In these ways, a KB and a
DSVS can make up for each other's weaknesses.


title: Graphenes flakes under controlled biaxial deformation

abstract:
  Thin membranes, such as monolayer graphene of monoatomic thickness, are bound
to exhibit lateral buckling under uniaxial tensile loading that impairs its
mechanical behaviour. In this work, we have developed an experimental device to
subject 2D materials to controlled equibiaxial strain on supported beams that
can be flexed up or down to subject the material to either compression or
tension, respectively. Using strain gauges in tandem with Raman spectroscopy
measurements, we monitor the G and 2D phonon properties of graphene under
biaxial strain and thus extract important information about the uptake of
stress under these conditions. The experimental shift over strain for the G and
2D Raman peaks were found to be in the range of 62.3 \pm 5 cm^-1/%, and 148.2
\pm 6 cm^-1/%, respectively, for monolayer but also bilayer graphenes. The
corresponding Gruneisen parameters for the G and 2D peaks were found to be
between 1.97 \pm 0.15 and 2.86 \pm 0.12, respectively. These values agree
reasonable well with those obtained from small-strain bubble-type experiments.
The results presented are also backed up by classical and ab initio molecular
dynamics simulations and excellent agreement of \Gamma-E2g shifts with strains
and the Gruneisen parameter was observed.


title:
Largest initial segments pointwise fixed by automorphisms of models of
  set theory

abstract:
  Given a model $\mathcal{M}$ of set theory, and a nontrivial automorphism $j$
of $\mathcal{M}$, let $\mathcal{I}_{\mathrm{fix}}(j)$ be the submodel of
$\mathcal{M}$ whose universe consists of elements $m$ of $\mathcal{M}$ such
that $j(x)=x$ for every $x$ in the transitive closure of $m$ (where the
transitive closure of $m$ is computed within $\mathcal{M}$). Here we study the
class $\mathcal{C}$ of structures of the form $\mathcal{I}_{\mathrm{fix}}(j)$,
where the ambient model $\mathcal{M}$ satisfies a frugal yet robust fragment of
$\mathrm{ZFC}$ known as $\mathrm{MOST}$, and $j(m)=m$ whenever $m$ is a finite
ordinal in the sense of $\mathcal{M}$. We show that every structure in
$\mathcal{C}$ satisfies
$\mathrm{MOST}+\Delta_0^\mathcal{P}\textrm{-Collection}$. We also show that the
following countable structures are in $\mathcal{C}$: (a) transitive models of
$\mathrm{MOST}+\Delta_0^\mathcal{P}\textrm{-Collection}$, (b) recursively
saturated models of $\mathrm{MOST}+\Delta_0^\mathcal{P}\textrm{-Collection}$,
(c) models of $\mathrm{ZFC}$. It follows from (b) that the theory of
$\mathcal{C}$ is precisely $\mathrm{MOST+\Delta}_{0}^{\mathcal{P}}$-Collection.
We conclude by proving a refinement of a result due to Amir Togha.


title:
Electronic Transport on the Shastry-Sutherland Lattice in Ising-type
  Rare Earth Tetraborides

abstract:
  In the presence of a magnetic field frustrated spin systems may exhibit
plateaus at fractional values of saturation magnetization. Such plateau states
are stabilized by classical and quantum mechanisms including order-by-disorder,
triplon crystallization, and various competing order effects. In the case of
electrically conducting systems, free electrons represent an incisive probe for
the plateau states. Here we study the electrical transport of Ising-type rare
earth tetraborides $R$B$_4$ ($R=$Er, Tm), a metallic Shastry-Sutherland lattice
showing magnetization plateaus. We find that the longitudinal and transverse
resistivities reflect scattering with both the static and dynamic plateau
structure. We model these results consistently with the expected strong
uniaxial anisotropy in a quantitative level, providing a framework for the
study of plateau states in metallic frustrated systems.


title:
Efficient molecular quantum dynamics in coordinate and phase space using
  pruned bases

abstract:
  We present an efficient implementation of dynamically pruned quantum
dynamics, both in coordinate space and in phase space. We combine the ideas
behind the biorthogonal von Neumann basis (PvB) with the orthogonalized
momentum-symmetrized Gaussians (Weylets) to create a new basis, projected
Weylets, that takes the best from both methods. We benchmark pruned dynamics
using phase-space-localized PvB, projected Weylets, and
coordinate-space-localized DVR bases, with real-world examples in up to six
dimensions. We show that coordinate-space localization is most important for
efficient pruning and that pruned dynamics is much faster compared to unpruned,
exact dynamics. Phase-space localization is useful for more demanding dynamics
where many basis functions are required. There, projected Weylets offer a more
compact representation than pruned DVR bases.


title:
Fluctuations of the Electromagnetic Local Density of States as a Probe
  for Structural Phase Switching

abstract:
  We study the statistics of the fluorescence decay rates for single quantum
emitters embedded in a scattering medium undergoing a phase transition. Under
certain circumstances, the structural properties of the scattering medium
explore a regime in which the system dynamically switches between two different
phases. While in that regime the light scattering properties of both phases are
hardly distinguishable, we demonstrate that the lifetime statistics of single
emitters with low diffusivity is clearly dependent on the dynamical state in
which the medium evolves. Hence, lifetime statistics provides clear signatures
of phase switching in systems where light scattering does not.


title: It ain't necessarily so: Basic sequent systems for negative modalities

abstract:
  We look at non-classical negations and their corresponding adjustment
connectives from a modal viewpoint, over complete distributive lattices, and
apply a very general mechanism in order to offer adequate analytic proof
systems to logics that are based on them. Defining non-classical negations
within usual modal semantics automatically allows one to treat equivalent
formulas as synonymous, and to have a natural justification for a global
version of the contraposition rule. From that perspective, our study offers a
particularly useful environment in which negative modalities and their
companions may be used for dealing with inconsistency and indeterminacy. After
investigating modal logics based on arbitrary frames, we extend the results to
serial frames, reflexive frames, functional frames, and symmetric frames. In
each case we also investigate when and how classical negation may thereby be
defined.


title: Hysteretic Faraday Waves

abstract:
  We report on the numerical and theoretical study of the subcritical
bifurcation of parametrically amplified waves appearing at the interface
between two immiscible incompressible fluids when the layer of the lower fluid
is very shallow. As a critical control parameter is surpassed, small amplitude
surface waves bifurcate towards highly nonlinear ones, with twice their
amplitude. We propose a simple phenomenological model which can describe the
observed bifurcation. We relate this hysteresis with the change of shear stress
using a simple stress balance, in agreement with numerical results.


title:
Space- and Time-resolved Resistive Measurement of Liquid Metal Wall
  Thickness

abstract:
  In a fusion reactor internally coated with liquid metal, it will be important
to diagnose the thickness of the liquid at various locations in the vessel, as
a function of time, and possibly respond to counteract undesired bulging or
depletion. The electrical conductance between electrodes immersed in the liquid
metal can be used as a simple proxy for the local thickness. Here a matrix of
electrodes is shown to provide spatially resolved measurements of liquid metal
thickness in the absence of plasma. First a theory is developed for mxn
electrodes, and then it is experimentally demonstrated for 3x1 electrodes. The
experiments were carried out with Galinstan, but are easily extended to Lithium
or other liquid metals.


title:
Boundary-field-driven control of discontinuous phase transitions on
  hyperbolic lattices

abstract:
  The multistate Potts models on two-dimensional hyperbolic lattices are
studied with respect to various boundary effects. The free energy is
numerically calculated by Corner Transfer Matrix Renormalization Group method.
We analyze phase transitions of the Potts models in the thermodynamic limit
with respect to contracted boundary layers. A false phase transition is present
even if a couple of the boundary layers are contracted. Its significance
weakens, as the number of the contracted boundary layers increases, until the
correct phase transition (deep inside the bulk) prevails over the false one.
For this purpose we derive a thermodynamic quantity, the so-called bulk excess
free energy, which depends on the contracted boundary layers and memorizes
additional boundary effects. In particular, the magnetic field is imposed on
the outermost boundary layer. While the boundary magnetic field does not affect
the second-order phase transition in the bulk if suppressing all the boundary
effects on the hyperbolic lattices, the first-order (discontinuous) phase
transition is significantly sensitive to the boundary magnetic field. Contrary
to the phase transition on the Euclidean lattices, the discontinuous phase
transition on the hyperbolic lattices can be continuously controlled (within a
certain temperature coexistence region) by varying the boundary magnetic field.


title: Three representations of the Ising model

abstract:
  Statistical models that analyse (pairwise) relations between variables
encompass assumptions about the underlying mechanism that generated the
associations in the observed data. In the present paper we demonstrate that
three Ising model representations exist that, although each proposes a distinct
theoretical explanation for the observed associations, are mathematically
equivalent. This equivalence allows the researcher to interpret the results of
one model in three different ways. We illustrate the ramifications of this by
discussing concepts that are conceived as problematic in their traditional
explanation, yet when interpreted in the context of another explanation make
immediate sense.

categories: stat.ME cond-mat.dis-nn cond-mat.stat-mech math.ST stat.TH


title: Dynamic physical layer equalization in optical communication networks

abstract:
  In optical transport networks, signal lightpaths between two terminal nodes
can be different due to current network conditions. Thus the transmission
distance and accumulated dispersion in the lightpath cannot be predicted.
Therefore, the adaptive compensation of dynamic dispersion is necessary in such
networks to enable flexible routing and switching. In this paper, we present a
detailed analysis on the adaptive dispersion compensation using the
least-mean-square (LMS) algorithm in coherent optical communication networks.
It is found that the variable-step-size LMS equalizer can achieve the same
performance with a lower complexity, compared to the traditional LMS algorithm.


title: Inferring Mechanisms for Global Constitutional Progress

abstract:
  Constitutions help define domestic political orders, but are known to be
influenced by two international mechanisms: one that reflects global temporal
trends in legal development, and another that reflects international network
dynamics such as shared colonial history. We introduce the provision space; the
growing set of all legal provisions existing in the world's constitutions over
time. Through this we uncover a third mechanism influencing constitutional
change: hierarchical dependencies between legal provisions, under which the
adoption of essential, fundamental provisions precedes more advanced
provisions. This third mechanism appears to play an especially important role
in the emergence of new political rights, and may therefore provide a useful
roadmap for advocates of those rights. We further characterise each legal
provision in terms of the strength of these mechanisms.


title:
Inducing Self-Organized Criticality in a network toy model by
  neighborhood assortativity

abstract:
  Complex networks are a recent type of frameworks used to study complex
systems with many interacting elements, such as Self-Organized Criticality
(SOC). The network node's tendency to link to other nodes of similar type is
characterized by assortative mixing. Real networks exhibit assortative mixing
by vertex degree, however typical random network models, such as Erdos-Renyi or
Barabasi-Albert, show no assortative arrangements. In this paper we introduce
the neighborhood assortativity notion, as the tendency of a node to belong to a
community (its neighborhood) showing an average property similar to its own.
Imposing neighborhood assortative mixing by degree in a network toy model, SOC
dynamics can be found. The long-range correlations resulting from the
criticality have been characterized by means of fluctuation analysis and show
an anticorrelation in the node's activity. The model contains only one
parameter and its statistics plots for different values of the parameter can be
collapsed into a single curve. The simplicity of the model allows performing
numerical simulations and also to study analytically the statistics for a
specific value of the parameter, making use of the Markov chains.


title:
The global non-linear stability of the Kerr-de Sitter family of black
  holes

abstract:
  We establish the full global non-linear stability of the Kerr-de Sitter
family of black holes, as solutions of the initial value problem for the
Einstein vacuum equations with positive cosmological constant, for small
angular momenta, and without any symmetry assumptions on the initial data. We
achieve this by extending the linear and non-linear analysis on black hole
spacetimes described in a sequence of earlier papers by the authors: We develop
a general framework which enables us to deal systematically with the
diffeomorphism invariance of Einstein's equations. In particular, the iteration
scheme used to solve Einstein's equations automatically finds the parameters of
the Kerr-de Sitter black hole that the solution is asymptotic to, the
exponentially decaying tail of the solution, and the gauge in which we are able
to find the solution; the gauge here is a wave map/DeTurck type gauge, modified
by source terms which are treated as unknowns, lying in a suitable
finite-dimensional space.


title: Photon-assisted shot noise in graphene in the Terahertz range

abstract:
  When subjected to electromagnetic radiation, the fluctuation of the
electronic current across a quantum conductor increases. This additional noise,
called photon-assisted shot noise, arises from the generation and subsequent
partition of electron-hole pairs in the conductor. The physics of
photon-assisted shot noise has been thoroughly investigated at microwave
frequencies up to 20 GHz, and its robustness suggests that it could be extended
to the Terahertz (THz) range. Here, we present measurements of the quantum shot
noise generated in a graphene nanoribbon subjected to a THz radiation. Our
results show signatures of photon-assisted shot noise, further demonstrating
that hallmark time-dependant quantum transport phenomena can be transposed to
the THz range.


title: Adaptivity vs Postselection

abstract:
  We study the following problem: with the power of postselection (classically
or quantumly), what is your ability to answer adaptive queries to certain
languages? More specifically, for what kind of computational classes
$\mathcal{C}$, we have $\mathsf{P}^{\mathcal{C}}$ belongs to $\mathsf{PostBPP}$
and $\mathsf{PostBQP}$? While a complete answer to the above question seems
impossible given the development of present computational complexity theory. We
study the analogous question in query complexity, which sheds light on the
limitation of {\em relativized} methods (the relativization barrier) to the
above question.
  Informally, we show that, for a partial function $f$, if there is no
efficient (In the world of query complexity, being efficient means using
$O(\operatorname*{polylog}(n))$ time.) {\em small bounded-error} algorithm for
$f$ classically or quantumly, then there is no efficient postselection
bounded-error algorithm to answer adaptive queries to $f$ classically or
quantumly. Our results imply a new proof for the classical oracle separation
$\mathsf{P}^{\mathsf{NP}^{\mathcal{O}}} \not\subset \mathsf{PP}^{\mathcal{O}}$.
They also lead to a new oracle separation
$\mathsf{P}^{\mathsf{SZK}^{\mathcal{O}}} \not\subset
\mathsf{PP}^{\mathcal{O}}$.
  Our result also implies a hardness amplification construction for polynomial
approximation: given a function $f$ on $n$ bits, we construct an
adaptive-version of $f$, denoted by $F$, on $O(m \cdot n)$ bits, such that if
$f$ requires large degree to approximate to error $2/3$ in a certain one-sided
sense, then $F$ requires large degree to approximate even to error $1/2 -
2^{-m}$. Our construction achieves the same amplification in the work of Thaler
(ICALP, 2016), by composing a function with $O(\log n)$ {\em deterministic
query complexity}.


title:
Measurement of the $W^{\pm}Z$ boson pair-production cross section in
  $pp$ collisions at $\sqrt{s}=13$ TeV with the ATLAS Detector

abstract:
  The production of $W^{\pm}Z$ events in proton--proton collisions at a
centre-of-mass energy of 13 TeV is measured with the ATLAS detector at the LHC.
The collected data correspond to an integrated luminosity of 3.2 fb$^{-1}$. The
$W^{\pm}Z$ candidates are reconstructed using leptonic decays of the gauge
bosons into electrons or muons. The measured inclusive cross section in the
detector fiducial region for leptonic decay modes is $\sigma_{W^\pm Z
\rightarrow \ell^{'} \nu \ell \ell}^{\textrm{fid.}} = 63.2 \pm 3.2$ (stat.)
$\pm 2.6$ (sys.) $\pm 1.5$ (lumi.) fb. In comparison, the next-to-leading-order
Standard Model prediction is $53.4^{+3.6}_{-2.8}$ fb. The extrapolation of the
measurement from the fiducial to the total phase space yields
$\sigma_{W^{\pm}Z}^{\textrm{tot.}} = 50.6 \pm 2.6$ (stat.) $\pm 2.0$ (sys.)
$\pm 0.9$ (th.) $\pm 1.2$ (lumi.) pb, in agreement with a recent
next-to-next-to-leading-order calculation of $48.2^{+1.1}_{-1.0}$ pb. The cross
section as a function of jet multiplicity is also measured, together with the
charge-dependent $W^+Z$ and $W^-Z$ cross sections and their ratio.


title: Black holes and Higgs stability

abstract:
  We study the effect of primordial black holes on the classical rate of
nucleation of AdS regions within the standard electroweak vacuum. We find that
the energy barrier for transitions to the new vacuum, which characterizes the
exponential suppression of the nucleation rate, can be reduced significantly in
the black-hole background. A precise analysis is required in order to determine
whether the the existence of primordial black holes is compatible with the form
of the Higgs potential at high temperature or density in the Standard Model or
its extensions.


title:
From superdeformation to extreme deformation and clusterization in the
  N~Z nuclei of the A~40 mass region

abstract:
  A systematic search for extremely deformed structures in the N~Z nuclei of
the A~40 mass region has been performed for the first time in the framework of
covariant density functional theory. At spin zero such structures are located
at high excitation energies which prevents their experimental observation. The
rotation acts as a tool to bring these exotic shapes to the yrast line or its
vicinity so that their observation could become possible with future generation
of $\gamma-$tracking (or similar) detectors such as GRETA and AGATA. The major
physical observables of such structures (such as transition quadrupole moments
as well as kinematic and dynamic moments of inertia), the underlying
single-particle structure and the spins at which they become yrast or near
yrast are defined. The search for the fingerprints of clusterization and
molecular structures is performed and the configurations with such features are
discussed. The best candidates for observation of extremely deformed structures
are identified. For several nuclei in this study (such as $^{36}$Ar), the
addition of several spin units above currently measured maximum spin of
$16\hbar$ will inevitably trigger the transition to hyper- and megadeformed
nuclear shapes.


title: The IDSA and the homogeneous sphere: Issues and possible improvements

abstract:
  In this paper, we are concerned with the study of the Isotropic Diffusion
Source Approximation (IDSA) (Baxter et al., Phys. Rev. E 73, 046118, 2006) of
radiative transfer. After having recalled well-known limits of the radiative
transfer equation, we present the IDSA and adapt it to the case of the
homogeneous sphere. We then show that for this example the IDSA suffers from
severe numerical difficulties. We argue that these difficulties originate in
the min-max switch coupling mechanism used in the IDSA. To overcome this
problem we reformulate the IDSA to avoid the problematic coupling. This allows
us to access the modeling error of the IDSA for the homogeneous sphere test
case. The IDSA is shown to overestimate the streaming component, hence we
propose a new version of the IDSA which is numerically shown to be more
accurate than the old one.
  Analytical results and numerical tests are provided to support the accuracy
of the new proposed approximation.


title: Activation of monogamy in non-locality using local contextuality

abstract:
  A unified view on the phenomenon of monogamy exhibited by Bell inequalities
and non-contextuality inequalities arising from the no-signaling and
no-disturbance principles is presented using the graph-theoretic method
introduced in \textit{Phys. Rev. Lett. 109, 050404 (2012)}. We propose a novel
type of trade-off, namely Bell inequalities that do not exhibit monogamy
features of their own can be activated to be monogamous by the addition of a
local contextuality term. This is illustrated by means of the well-known
$\mathcal{I}_{3322}$ inequality, and reveals a resource trade-off between
bipartite correlations and the local purity of a single system. In the
derivation of novel no-signaling monogamies, we uncover a new feature, namely
that two-party Bell expressions that are trivially classically saturated can
become non-trivial upon the addition of an expression involving a third party
with a single measurement input.


title:
Joint Channel Estimation and Training Signal Design for Two-way MIMO
  Relay Systems

abstract:
  In this paper, a two-stage channel estimation scheme for two-way MIMO relay
systems with a single relay antenna is proposed. The backward channel is
estimated by using linear minimum mean square estimator (LMMSE) at the first
stage, where the optimal training signal is designed. We then mainly focus on
the forward channel estimation by using singular value decomposition (SVD)
based maximum likelihood method, and the related training signal is proposed.
We note that the forward channel estimator is nonlinear and by analyzing the
asymptotic Bayesian Cramer-rao Lower Bound (BCRLB), we seek BCRLB as the
criterion for training signal design. Finally, the numerical results show that
the proposed training signal can improve the MSE performance.


title: Spectral Representations and Global Maps of Cellular Automata Dynamics

abstract:
  We present a spectral representation of any computation performed by a
Cellular Automaton (CA) of arbitrary topology and dimensionality via an
appropriate coding scheme in Fourier space that can be implemented in an analog
machine ideally circumventing part of the overall waste heat production. We
explore further consequences of this encoding and we provide a simple example
based on the Game-of-Life where we find global maps for small lattices
indicating an interesting underlying recursive structure.


title:
Design and construction of a point-contact spectroscopy rig with lateral
  scanning capability

abstract:
  The design and realization of a cryogenic rig for point-contact spectroscopy
measurements in the needle-anvil configuration is presented. Thanks to the use
of two piezoelectric nano-positioners, the tip can move along the vertical
($z$) and horizontal ($x$) direction and thus the rig is suitable to probe
different regions of a sample \textit{in situ}. Moreover, it can also form
double point-contacts on different facets of a single crystal for achieving,
e.g., an interferometer configuration for phase-sensitive measurements. For the
latter purpose, the sample holder can also host a Helmholtz coil for applying a
small transverse magnetic field to the junction. A semi-rigid coaxial cable can
be easily added for studying the behavior of Josephson junctions under
microwave irradiation. The rig can be detached from the probe and thus used
with different cryostats. The performance of this new probe has been tested in
a Quantum Design PPMS system by conducting point-contact Andreev reflection
measurements on Nb thin films over large areas as a function of temperature and
magnetic field.


title: Topological properties of function spaces over ordinals

abstract:
  A topological space $X$ is said to be an Ascoli space if any compact subset
$K$ of $C_k(X)$ is evenly continuous. This definition is motivated by the
classical Ascoli theorem. We study the $k_R$-property and the Ascoli property
of $C_p(\kappa)$ and $C_k(\kappa)$ over ordinals $\kappa$. We prove that
$C_p(\kappa)$ is always an Ascoli space, while $C_p(\kappa)$ is a $k_R$-space
iff the cofinality of $\kappa$ is countable. In particular, this provides the
first $C_p$-example of an Ascoli space which is not a $k_R$-space, namely
$C_p(\omega_1)$. We show that $C_k(\kappa)$ is Ascoli iff $cf(\kappa)$ is
countable iff $C_k(\kappa)$ is metrizable.


title:
Tridimensional to bidimensional transition in magnetohydrodynamic
  turbulence with a guide field and kinetic helicity injection

abstract:
  We study the transition in dimensionality of a three-dimensional
magnetohydrodynamic flow forced only mechanically, when the strength of a
magnetic guiding field is gradually increased. We use numerical simulations to
consider cases in which the mechanical forcing injects (or not) helicity in the
flow. As the guiding field is increased, the strength of the magnetic field
fluctuations decrease as a power law of the guiding field intensity. We show
that for strong enough guiding fields, the helical magnetohydrodynamic flow can
become almost two-dimensional. In this case, the mechanical energy can undergo
a process compatible with an inverse cascade, being transferred preferentially
towards scales larger than the forcing scale. The presence of helicity changes
the spectral scaling of the small magnetic field fluctuations, and affects the
statistics of the velocity field and of the velocity gradients. Moreover, at
small scales the dynamics of the flow becomes dominated by a direct cascade of
helicity, which can be used to derive scaling laws for the velocity field.


title: Some elementary examples of non-liftable schemes

abstract:
  We present some simple examples of smooth projective varieties in positive
characteristic, arising from linear algebra, which do not admit a lifting
neither to characteristic zero, nor to the ring of second Witt vectors. Our
first construction is the blow-up of the graph of the Frobenius morphism of a
homogeneous space. The second example is a blow-up of $\mathbb{P}^3$ in a
'purely characteristic-$p$' configuration of points and lines.


title:
Change of nuclear configurations in the neutrinoless double-$\beta$
  decay of $^{130}$Te $\rightarrow$ $^{130}$Xe and $^{136}$Xe $\rightarrow$
  $^{136}$Ba

abstract:
  The change in the configuration of valence protons between the initial and
final states in the neutrinoless double-$\beta$ decay of $^{130}$Te
$\rightarrow$ $^{130}$Xe and of $^{136}$Xe $\rightarrow$ $^{136}$Ba has been
determined by measuring the cross sections of the ($d$,$^3$He) reaction with
101-MeV deuterons. Together with our recent determination of the relevant
neutron configurations involved in the process, a quantitative comparison with
the latest shell-model and interacting-boson-model calculations reveals
significant discrepancies. These are the same calculations used to determine
the nuclear matrix elements governing the rate of neutrinoless double-$\beta$
decay in these systems.


title: A Conjecture about Periods in Subtraction Games

abstract:
  We make a conjecture that characterizes the periods of the nim values in
subtraction games with subtraction set of size 3.


title: Exact simulation of coined quantum walks with the continuous-time model

abstract:
  The connection between coined and continuous-time quantum walk models has
been addressed in a number of papers. In most of those studies, the
continuous-time model is derived from coined quantum walks by employing
dimensional reduction and taking appropriate limits. In this work, we produce
the evolution of a coined quantum walk on a generic graph using a
continuous-time quantum walk on a larger graph. In addition to expanding the
underlying structure, we also have to switch on and off edges during the
continuous-time evolution to accommodate the alternation between the shift and
coin operators from the coined model. In one particular case, the connection is
very natural, and the continuous-time quantum walk that simulates the coined
quantum walk is driven by the graph Laplacian on the dynamically changing
expanded graph.


title: String-Based Borsuk-Ulam Theorem

abstract:
  This paper introduces a string-based extension of the Borsuk-Ulam Theorem
(denoted by strBUT). A string is a region with zero width and either bounded or
unbounded length on the surface of an $n$-sphere or a region of a normed linear
space. In this work, an $n$-sphere surface is covered by a collection of
strings. For a strongly proximal continuous function on an $n$-sphere into
$n$-dimensional Euclidean space, there exists a pair of antipodal $n$-sphere
strings with matching descriptions that map into Euclidean space
$\mathbb{R}^n$. Each region $M$ of a string-covered $n$-sphere is a worldsheet
(denoted by $\mbox{wsh}M$). For a strongly proximal continuous mapping from a
worldsheet-covered $n$-sphere to $\mathbb{R}^n$, strongly near antipodal
worldsheets map into the same region in $\mathbb{R}^n$. An application of
strBUT is given in terms of the evaluation of Electroencephalography (EEG)
patterns.


title: Yukawa Unification in Heterotic String Theory

abstract:
  We analyze Yukawa unification in the the context of $E_8\times E_8$ heterotic
Calabi-Yau models which rely on breaking to a GUT theory via a non-flat gauge
bundle and subsequent Wilson line breaking to the standard model. Our focus is
on underlying GUT theories with gauge group $SU(5)$ or $SO(10)$. We provide a
detailed analysis of the fact that, in contrast to traditional field theory
GUTs, the underlying GUT symmetry of these models does not enforce Yukawa
unification. Using this formalism, we present various scenarios where Yukawa
unification can occur as a consequence of additional symmetries. These
additional symmetries arise naturally in some heterotic constructions and we
present an explicit heterotic line bundle model which realizes one of these
scenarios.


title:
Designing Commercial Therapeutic Robots for Privacy Preserving Systems
  and Ethical Research Practices within the Home

abstract:
  The migration of robots from the laboratory into sensitive home settings as
commercially available therapeutic agents represents a significant transition
for information privacy and ethical imperatives. We present new privacy
paradigms and apply the Fair Information Practices (FIPs) to investigate
concerns unique to the placement of therapeutic robots in private home
contexts. We then explore the importance and utility of research ethics as
operationalized by existing human subjects research frameworks to guide the
consideration of therapeutic robotic users -- a step vital to the continued
research and development of these platforms. Together, privacy and research
ethics frameworks provide two complementary approaches to protect users and
ensure responsible yet robust information sharing for technology development.
We make recommendations for the implementation of these principles -- paying
particular attention to specific principles that apply to vulnerable
individuals (i.e., children, disabled, or elderly persons)--to promote the
adoption and continued improvement of long-term, responsible, and
research-enabled robotics in private settings.


title:
Spectral decomposition of fractional operators and a reflected stable
  semigroup

abstract:
  In this paper, we provide the spectral decomposition in Hilbert space of the
$\mathcal{C}_0$-semigroup $P$ and its adjoint $\hatP$ having as generator,
respectively, the Caputo and the right-sided Riemann-Liouville fractional
derivatives of index $1<\alpha<2$. These linear operators, which are non-local
and non-self-adjoint, appear in many recent studies in applied mathematics and
also arise as the infinitesimal generators of some substantial processes such
as the reflected spectrally negative $\alpha$-stable process. Our approach
relies on intertwining relations that we establish between these semigroups and
the semigroup of a Bessel type process whose generator is a self-adjoint second
order differential operator. In particular, from this commutation relation, we
characterize the positive real axis as the continuous point spectrum of $P$ and
provide a power series representation of the corresponding eigenfunctions. We
also identify the positive real axis as the residual spectrum of the adjoint
operator $\hatP$ and elucidates its role in the spectral decomposition of these
operators. By resorting to the concept of continuous frames, we proceed by
investigating the domain of the spectral operators and derive two
representations for the heat kernels of these semigroups. As a by-product, we
also obtain regularity properties for these latter and also for the solution of
the associated Cauchy problem.


title:
Appraisal of the realistic accuracy of Molecular dynamics of high
  pressure hydrogen

abstract:
  Molecular dynamics is a powerful method for studying the behaviour of
materials at high temperature. In practice, however, its effectiveness in
representing real systems is limited by the accuracy of the forces, finite size
effects, quantization, and equilibration methods. In this paper we report and
discuss some calculations carried out using molecular dynamics on high pressure
hydrogen, reviewing a number of sources of error. We find that the neglect of
zero-point vibrations is quantitively the largest. We show that simulations
using ab initio molecular dynamics with the PBE functional predict a large
stability field for the molecular Cmca-4 structure at pressures just above
those achieved in current experiments above the stability range of the mixed-
molecular layered Phase IV. However, the various errors in the simulation all
point towards a much smaller stability range, and the likelihood of a
non-molecular phase based on low-coordination networks or chains of atoms.


title: Microservices: yesterday, today, and tomorrow

abstract:
  Microservices is an architectural style inspired by service-oriented
computing that has recently started gaining popularity. Before presenting the
current state-of-the-art in the field, this chapter reviews the history of
software architecture, the reasons that led to the diffusion of objects and
services first, and microservices later. Finally, open problems and future
challenges are introduced. This survey primarily addresses newcomers to the
discipline, while offering an academic viewpoint on the topic. In addition, we
investigate some practical issues and point out some potential solutions.


title: Coordinated Multi-area Economic Dispatch via Critical Region Projection

abstract:
  A coordinated economic dispatch method for multi-area power systems is
proposed. Choosing boundary phase angles as coupling variables, the proposed
method exploits the structure of critical regions in local problems defined by
active and inactive constraints. For a fixed boundary state given by the
coordinator, local operators compute the coefficients of critical regions
containing the boundary state and of the optimal cost functions then
communicate them to the coordinator who in turn optimizes the boundary state to
minimize the overall cost. By iterating between local operators and the
coordinator, the proposed algorithm converges to the global optimal solution in
finite steps, and it requires limited information sharing.


title: Trace Norm Regularised Deep Multi-Task Learning

abstract:
  We propose a framework for training multiple neural networks simultaneously.
The parameters from all models are regularised by the tensor trace norm, so
that each neural network is encouraged to reuse others' parameters if possible
-- this is the main motivation behind multi-task learning. In contrast to many
deep multi-task learning models, we do not predefine a parameter sharing
strategy by specifying which layers have tied parameters. Instead, our
framework considers sharing for all shareable layers, and the sharing strategy
is learned in a data-driven way.


title:
The Sound of Silence: equilibrium filtering and optimal censoring in
  financial markets

abstract:
  Following the approach of standard filtering theory, we analyse
investor-valuation of firms, when these are modelled as geometric-Brownian
state processes that are privately and partially observed, at random (Poisson)
times, by agents. Tasked with disclosing forecast values, agents are able
purposefully to withhold their observations; explicit filtering formulas are
derived for downgrading the valuations in the absence of disclosures. The
analysis is conducted for both a solitary firm and m co-dependent firms.


title: Simplices over finite fields

abstract:
  We prove that, provided $d > k$, every sufficiently large subset of
$\mathbf{F}_q^d$ contains an isometric copy of every $k$-simplex that avoids
spanning a nontrivial self-orthogonal subspace. We obtain comparable results
for simplices exhibiting self-orthogonal behavior.


title:
Supergranulation as the largest buoyantly driven convective scale of the
  Sun

abstract:
  Supergranulation is characterized by horizontally divergent flows with
typical length scales of 32 Mm in the solar photosphere. Unlike granulation,
the size of which is comparable to both the thickness of the radiative boundary
layer and local scale height of the plasma in the photosphere, supergranulation
does not reflect any obvious length scale of the solar convection zone. Early
suggestions that the depth of second helium ionization is important are not
supported by numerical simulations. Thus the origin of the solar
supergranulation remains largely a mystery. Moreover, observations of flows in
the photosphere using either Doppler imaging or correlation or feature tracking
show a monotonic decrease in power at scales larger than supergranulation. Both
local area and global spherical shell simulations of solar convection by
contrast show the opposite, a power law increase in horizontal flow amplitudes
to low wavenumber. Here we examine this disparity, and investigate how the
solar supergranulation may arise as a consequence of strong photospheric
driving and non-local heat transport by cool diving plumes. Using three
dimensional anelastic simulations with surface driving, we show that the
kinetic energy of largest convective scales in the upper layers of a stratified
domain reflects the depth of transition from strong buoyant driving to
adiabatic stratification below. We interpret the observed monotonic decrease in
solar convective power at scales larger than supergranulation to be a
consequence of this rapid transition, and show how the supergranular scale can
be understood as the largest buoyantly driven mode of convection in the Sun.


title: Randomized Ternary Search Tries

abstract:
  This paper presents a new kind of self-balancing ternary search trie that
uses a randomized balancing strategy adapted from Aragon and Seidel's
randomized binary search trees ("treaps"). After any sequence of insertions and
deletions of strings, the tree looks like a ternary search trie built by
inserting strings in random order. As a result, the time cost of searching,
inserting, or deleting a string of length k in a tree with n strings is at most
O(k + log n) with high probability.


title:
Crystallographic features and state stability of the decagonal
  quasicrystal in the Al-Co-Cu alloy system

abstract:
  In the Al-Co-Cu alloy system, both the decagonal quasicrystal with the space
group of $P\overline{10}m2$ and its approximant Al$_{13}$Co$_4$ phase with
monoclinic $Cm$ symmetry are present around 20 at.% Co-10 at.% Cu. In this
study, we examined the crystallographic features of prepared Al-(30-x) at.%
Co-x at.% Cu samples mainly by transmission electron microscopy in order to
make clear the crystallographic relation between the decagonal quasicrystal and
the monoclinic Al$_{13}$Co$_4$ structure. The results revealed a coexistence
state consisting of decagonal quasicrystal and approximant Al$_{13}$Co$_4$
regions in Al-20 at.% Co-10 at.% Cu alloy samples. With the help of the
coexistence state, the orientation relationship was established between the
monoclinic Al$_{13}$Co$_4$ structure and the decagonal quasicrystal. In the
determined relationship, the crystallographic axis in the quasicrystal was
found to be parallel to the normal direction of the (010)$_{\rm m}$ plane in
the Al$_{13}$Co$_4$ structure, where the subscript m denotes the monoclinic
system. Based on data obtained experimentally, the state stability of the
decagonal quasicrystal was also examined in terms of the Hume-Rothery (HR)
mechanism on the basis of the nearly-free-electron approximation. It was found
that a model based on the HR mechanism could explain the crystallographic
features such as electron diffraction patterns and atomic arrangements found in
the decagonal quasicrystal. In other words, the HR mechanism is most likely
appropriate for the stability of the decagonal quasicrystal in the Al-Co-Cu
alloy system.


title: Nontrivial UV behavior of rank-4 tensor field models for quantum gravity

abstract:
  We investigate the universality classes of rank-4 colored bipartite U(1)
tensor field models near the Gaussian fixed point with the functional
renormalization group. In a truncation that contains all power counting
relevant and marginal operators, we find a one-dimensional UV attractor that is
connected with the Gaussian fixed point. Hence this is first evidence that the
model could be asymptotically safe due to a mechanism similar to the one found
in the Grosse-Wulkenhaar model, whose UV behavior near the Gaussian fixed point
is also described by one-dimensional attractor that contains the Gaussian fixed
point. However, the cancellation mechanism that is responsible for the
simultaneous vanishing of the beta functions is new to tensor models, i.e. it
does not occur in vector or matrix models.


title: Photon gas thermodynamics in dS and AdS momentum spaces

abstract:
  In this paper, we study thermostatistical properties of a photon gas in the
framework of two deformed special relativity models defined by the cosmological
coordinatizations of the de Sitter (dS) and anti-de Sitter (AdS) momentum
spaces. The dS model is a doubly special relativity theory in which an
ultraviolet length scale is invariant under the deformed Lorentz
transformations. For the case of AdS model, however, the Lorentz symmetry
breaks at the high energy regime. We show that the existence of a maximal
momentum in dS momentum space leads to maximal pressure and temperature at the
thermodynamical level while maximal internal energy and entropy arise for the
case of the AdS momentum space due to the existence of a maximal kinematical
energy. These results show the thermodynamical duality of these models much
similar to their well-known kinematical duality.


title: Weak symmetric integrals with respect to the fractional Brownian motion

abstract:
  The aim of this paper is to establish the weak convergence, in the topology
of the Skorohod space, of the $\nu$-symmetric Riemann sums for functionals of
the fractional Brownian motion when the Hurst parameter takes the critical
value $H=(4\ell+2)^{-1}$, where $\ell=\ell(\nu)\geq 1$ is the largest natural
number satisfying $\int_0^1 \alpha^{2j}\nu(d\alpha)=(2j+1)^{-1}$ for all
$j=0,\ldots,\ell-1$. As a consequence, we derive a change-of-variable formula
in distribution, where the correction term is a stochastic integral with
respect to a Brownian motion that is independent of the fractional Brownian
motion.


title: EPIC201702477b: A Long Period Transiting Brown Dwarf from K2

abstract:
  We report the discovery of EPIC201702477b, a transiting brown dwarf in a long
period (40.73691 +/- 0.00037 day) and eccentric (e=0.2281 +/- 0.0026) orbit.
This system was initially reported as a planetary candidate based on two
transit events seen in K2 Campaign 1 photometry and later validated as an
exoplanet. We confirm the transit and refine the ephemeris with two subsequent
ground-based detections of the transit using the LCOGT 1m telescope network. We
rule out any transit timing variations above the level of 30s. Using high
precision radial velocity measurements from HARPS and SOPHIE we identify the
transiting companion as a brown dwarf with a mass, radius, and bulk density of
66.9 +/- 1.7 M$_J$, 0.757 +/- 0.065 R$_J$, and 191+/-51 g.cm$^{-3}$
respectively. EPIC201702477b is the smallest radius brown dwarf yet discovered,
with a mass just below the H-burning limit. It has the highest density of any
planet, substellar mass object or main-sequence star discovered so far. We find
evidence in the set of known transiting brown dwarfs for two populations of
objects - high mass brown dwarfs and low mass brown dwarfs. The higher-mass
population have radii in very close agreement to theoretical models, and show a
lower-mass limit around 60 M$_J$. This may be the signature of mass-dependent
ejection of systems during the formation process.


title:
On the Milnor monodromy of the irreducible complex reflection
  arrangements

abstract:
  Using recent results by A. Macinic, S. Papadima and R. Popescu, and a
refinement of an older construction of ours, we determine the monodromy action
on $H^1(F(G),C)$, where $F(G)$ denotes the Milnor fiber of a hyperplane
arrangement associated to an irreducible complex reflection group $G$.


title: The Distribution of Integers in a Totally Real Cubic Field

abstract:
  Hecke studies the distribution of fractional parts of quadratic irrationals
with Fourier expansion of Dirichlet series. This method is generalized by
Behnke and Ash-Friedberg, to study the distribution of the number of totally
positive integers of given trace in a general totally real number field of any
degree. When the field is cubic, we show that the asymptotic behavior of a
weighted Diophantine sum is related to the structure of the unit group. The
main term can be expressed in terms of Gr\"ossencharacter $L$-functions.


title: Birth-death processes with quenched uncertainty and intrinsic noise

abstract:
  The dynamics of populations is frequently subject to intrinsic noise. At the
same time unknown interaction networks or rate constants can present quenched
uncertainty. Existing approaches often involve repeated sampling of the
quenched disorder and then running the stochastic birth-death dynamics on these
samples. In this paper we take a different view, and formulate an effective
jump process, representative of the ensemble of quenched interactions as a
whole. Using evolutionary games with random payoff matrices as an example, we
develop an algorithm to simulate this process, and we discuss diffusion
approximations in the limit of weak intrinsic noise.


title:
Minority-carrier dynamics in semiconductors probed by two-photon
  microscopy

abstract:
  Two-photon time-resolved photoluminescence has been recently applied to
various semiconductor devices to determine carrier lifetime and surface
recombination velocities. So far the theoretical modeling activity has been
mainly limited to the commonly used one-photon counterpart of the technique.
Here we provide the analytical solution to a 3D diffusion equation that
describes two-photon microscopy in the low-injection regime. We focus on a
system with a single buried interface with enhanced recombination, and analyze
how transport, bulk and surface recombinations influence photoluminescence
decays. We find that bulk measurements are dominated by diffusion at short
times and by bulk recombination at long times. Surface recombination modifies
bulk signals when the optical spot is less than a diffusion length away from
the probed interface. In addition, the resolution is increased as the spot size
is reduced, which however makes the signal more sensitive to diffusion.


title: Dialog state tracking, a machine reading approach using Memory Network

abstract:
  In an end-to-end dialog system, the aim of dialog state tracking is to
accurately estimate a compact representation of the current dialog status from
a sequence of noisy observations produced by the speech recognition and the
natural language understanding modules. This paper introduces a novel method of
dialog state tracking based on the general paradigm of machine reading and
proposes to solve it using an End-to-End Memory Network, MemN2N, a
memory-enhanced neural network architecture. We evaluate the proposed approach
on the second Dialog State Tracking Challenge (DSTC-2) dataset. The corpus has
been converted for the occasion in order to frame the hidden state variable
inference as a question-answering task based on a sequence of utterances
extracted from a dialog. We show that the proposed tracker gives encouraging
results. Then, we propose to extend the DSTC-2 dataset with specific reasoning
capabilities requirement like counting, list maintenance, yes-no question
answering and indefinite knowledge management. Finally, we present encouraging
results using our proposed MemN2N based tracking model.


title:
Upper Bound on the Gluino Mass in Supersymmetric Models with Extra
  Matters

abstract:
  We discuss the upper bound on the gluino mass in supersymmetric models with
vector-like extra matters. In order to realize the observed Higgs mass of 125
GeV, the gluino mass is bounded from above in supersymmetric models. With the
existence of the vector-like extra matters at around TeV, we show that such an
upper bound on the gluino mass is significantly reduced compared to the case of
minimal supersymmetric standard model. This is due to the fact that radiatively
generated stop masses as well the stop trilinear coupling are enhanced in the
presence of the vector-like multiplets. In a wide range of parameter space of
the model with extra matters, the gluino is required to be lighter than $\sim
3$ TeV, which is likely to be within the reach of forthcoming LHC experiment.


title:
Connecting Leptonic Unitarity Triangle to Neutrino Oscillation with CP
  Violation in Vacuum and in Matter

abstract:
  Leptonic unitarity triangle (LUT) provides fundamental means to geometrically
describe CP violation in neutrino oscillation. In this work, we use LUT to
present a new geometrical interpretation of the vacuum oscillation probability,
and derive a compact new oscillation formula in terms of only 3 independent
parameters of the corresponding LUT. Then, we systematically study matter
effects in the geometrical formulation of neutrino oscillation with CP
violation. Including nontrivial matter effects, we derive a very compact new
oscillation formula by using the LUT formulation. We further demonstrate that
this geometrical formula holds well for applications to neutrino oscillations
in matter, including the long baseline experiments T2K, MINOS, NOvA, and DUNE.


title:
A modified single and multi-objective bacteria foraging optimization for
  the solution of quadratic assignment problem

abstract:
  Non-polynomial hard (NP-hard) problems are challenging because no
polynomial-time algorithm has yet been discovered to solve them in polynomial
time. The Bacteria Foraging Optimization (BFO) algorithm is one of the
metaheuristics algorithms that is mostly used for NP-hard problems. BFO is
inspired by the behavior of the bacteria foraging such as Escherichia coli
(E-coli). The aim of BFO is to eliminate those bacteria that have weak foraging
properties and maintain those bacteria that have breakthrough foraging
properties toward the optimum. Despite the strength of this algorithm, most of
the problems reaching optimal solutions are time-demanding or impossible. In
this paper, we modified single objective BFO by adding a mutation operator and
multi-objective BFO (MOBFO) by adding mutation and crossover from genetic
algorithm operators to update the solutions in each generation, and local tabu
search algorithm to reach the local optimum solution. Additionally, we used a
fast nondominated sort algorithm in MOBFO to find the best-nondominated
solutions in each generation. We evaluated the performance of the proposed
algorithms through a number of single and multi-objective Quadratic Assignment
Problem (QAP) instances. The experimental results show that our approaches
outperform some previous optimization algorithms in both convergent and
divergent solutions.


title:
On the exact learnability of graph parameters: The case of partition
  functions

abstract:
  We study the exact learnability of real valued graph parameters $f$ which are
known to be representable as partition functions which count the number of
weighted homomorphisms into a graph $H$ with vertex weights $\alpha$ and edge
weights $\beta$. M. Freedman, L. Lov\'asz and A. Schrijver have given a
characterization of these graph parameters in terms of the $k$-connection
matrices $C(f,k)$ of $f$. Our model of learnability is based on D. Angluin's
model of exact learning using membership and equivalence queries. Given such a
graph parameter $f$, the learner can ask for the values of $f$ for graphs of
their choice, and they can formulate hypotheses in terms of the connection
matrices $C(f,k)$ of $f$. The teacher can accept the hypothesis as correct, or
provide a counterexample consisting of a graph. Our main result shows that in
this scenario, a very large class of partition functions, the rigid partition
functions, can be learned in time polynomial in the size of $H$ and the size of
the largest counterexample in the Blum-Shub-Smale model of computation over the
reals with unit cost.


title: Weak universality in sensory tradeoffs

abstract:
  For many organisms, the number of sensory neurons is largely determined
during development, before strong environmental cues are present. This is
despite the fact that environments can fluctuate drastically both from
generation to generation and within an organism's lifetime. How can organisms
get by by hard-coding the number of sensory neurons? We approach this question
using rate-distortion theory. A combination of simulation and theory suggests
that when environments are large, the rate-distortion function---a proxy for
material costs, timing delays, and energy requirements---depends only on
coarse-grained environmental statistics that are expected to change on
evolutionary, rather than ontogenetic, timescales.


title: Noise-induced absorbing phase transition in a model of opinion formation

abstract:
  In this work we study a 3-state ($+1$, $-1$, $0$) opinion model in the
presence of noise and disorder. We consider pairwise competitive interactions,
with a fraction $p$ of those interactions being negative (disorder). Moreover,
there is a noise $q$ that represents the probability of an individual
spontaneously change his opinion to the neutral state. Our aim is to study how
the increase/decrease of the fraction of neutral agents affects the critical
behavior of the system and the evolution of opinions. We derive analytical
expressions for the order parameter of the model, as well as for the stationary
fraction of each opinion, and we show that there are distinct phase
transitions. One is the usual ferro-paramagnetic transition, that is in the
Ising universality class. In addition, there are para-absorbing and
ferro-absorbing transitions, presenting the directed percolation universality
class. Our results are complemented by numerical simulations.


title: Reducibility versus definability for pseudovarieties of semigroups

abstract:
  It is easy to show that a pseudovariety which is reducible with respect to an
implicit signature $\sigma$ for the equation $x=y$ can also be defined by
$\sigma$-identities. We present several negative examples for the converse
using signatures in which the pseudovarieties are usually defined. An ordered
example issue from the extended Straubing-Th\'erien hierarchy of regular
languages is also shown to provide a positive example for the inequality $x\le
y$.


title: A note on viability of nonminimally coupled $f(R)$ theory

abstract:
  Consistency conditions for nonminimally coupled $f(R)$ theories have been
derived by requiring the absence of tachyons and instabilities in the scalar
fluctuations. This note confirms these results and clarifies a subtlety
regarding different definitions of sound speeds.


title:
Dynamical Casimir effect of phonon excitation in the dispersive regime
  of cavity optomechanics

abstract:
  In this paper, we theoretically propose and investigate a feasible
experimental scheme for realizing the dynamical Casimir effect (DCE) of phonons
in an optomechanical setup formed by a ground-state precooled mechanical
oscillator (MO) inside a Fabry-P{\'e}rot cavity, which is driven by an
amplitude-modulated classical laser field in the dispersive (far-detuned)
regime. The time modulation of the driving field leads to the parametric
amplification of the mechanical vacuum fluctuations of the MO, which results in
the generation of Casimir phonons over time scales longer than the cavity
lifetime. We show that the generated phonons exhibit quadrature squeezing,
bunching effect, and super-Poissonian statistics which are controllable by the
externally modulated laser pump. In particular, we find that the scheme allows
for a perfect squeezing transfer from one mechanical quadrature to another when
the laser frequency is varied from red detuning to blue detuning. Moreover, by
analyzing the effect of the thermal noise of the MO environment, we find that
there exists a critical temperature above which there is no phonon quadrature
squeezing to occur. We also show that in the presence of time modulation of the
driving laser the linewidth narrowing of the displacement spectrum of the MO
can be considered as a signature of the generation of Casimir phonons.


title: Causal transport in discrete time and applications

abstract:
  Loosely speaking, causal transport plans are a relaxation of adapted
processes in the same sense as Kantorovich transport plans extend Monge-type
transport maps. The corresponding causal version of the transport problem has
recently been introduced by Lassalle. Working in a discrete time setup, we
establish a dynamic programming principle that links the causal transport
problem to the transport problem for general costs recently considered by
Gozlan et al. Based on this recursive principle, we give conditions under which
the celebrated Knothe-Rosenblatt rearrangement can be viewed as a causal
analogue to the Brenier's map. Moreover, these considerations provide
transport-information inequalities for the nested distance between stochastic
processes pioneered by Pflug and Pichler, and so serve to gauge the discrepancy
between stochastic programs driven by different noise distributions.


title: Microorganism billiards in closed plane curves

abstract:
  Recent experiments have shown that many species of microorganisms leave a
solid surface at a fixed angle determined by steric interactions and near-field
hydrodynamics. This angle is completely independent of the incoming angle. For
several collisions in a closed body this determines a unique type of billiard
system, an aspecular billiard in which the outgoing angle is fixed for all
collisions. We analyze such a system using numerical simulation of this
billiard for varying tables and outgoing angles, and also utilize the theory of
one-dimensional maps and wavefront dynamics. When applicable we cite results
from and compare our system to similar billiard systems in the literature. We
focus on examples from three broad classes: the ellipse, the Bunimovich
billiards, and the Sinai billiards. The effect of a noisy outgoing angle is
also discussed.


title: Non-destructive profilometry of optical nanofibres

abstract:
  Single-mode optical nanofibres are a central component of a broad range of
applications and emerging technologies. Their fabrication has been extensively
studied over the past decade, but imaging of the final sub-micrometre products
has been restricted to destructive or low-precision techniques. Here we
demonstrate an optical scattering-based scanning method that uses a probe
nanofibre to locally scatter the evanescent field of a sample nanofibre. The
method does not damage the sample nanofibre and is easily implemented only
using the same equipment as in a standard fibre puller setup. We demonstrate
sub-nanometre radial resolution at video rates (0.7 nm in 10 ms) on single mode
nanofibres, allowing for a complete high-precision profile to be obtained
within minutes of fabrication. The method thus enables non-destructive, fast
and precise characterisation of optical nanofibers, with applications ranging
from optical sensors and cold atom traps to non-linear optics.


title: Quasimodularity and large genus limits of Siegel-Veech constants

abstract:
  Quasimodular forms were first studied in the context of counting torus
coverings. Here we show that a weighted version of these coverings with
Siegel-Veech weights also provides quasimodular forms. We apply this to prove
conjectures of Eskin and Zorich on the large genus limits of Masur-Veech
volumes and of Siegel-Veech constants.
  In Part I we connect the geometric definition of Siegel-Veech constants both
with a combinatorial counting problem and with intersection numbers on Hurwitz
spaces. We introduce modified Siegel-Veech weights whose generating functions
will later be shown to be quasimodular.
  Parts II and III are devoted to the study of the quasimodularity of the
generating functions arising from weighted counting of torus coverings. The
starting point is the theorem of Bloch and Okounkov saying that q-brackets of
shifted symmetric functions are quasimodular forms. In Part II we give an
expression for their growth polynomials in terms of Gaussian integrals and use
this to obtain a closed formula for the generating series of cumulants that is
the basis for studying large genus asymptotics. In Part III we show that the
even hook-length moments of partitions are shifted symmetric polynomials and
prove a formula for the q-bracket of the product of such a hook-length moment
with an arbitrary shifted symmetric polynomial. This formula proves
quasimodularity also for the (-2)-nd hook-length moments by extrapolation, and
implies the quasimodularity of the Siegel-Veech weighted counting functions.
  Finally, in Part IV these results are used to give explicit generating
functions for the volumes and Siegel-Veech constants in the case of the
principal stratum of abelian differentials. To apply these exact formulas to
the Eskin-Zorich conjectures we provide a general framework for computing the
asymptotics of rapidly divergent power series.


title:
Electronic and magnetic structures and bonding properties of Ce2CrN3 and
  U2CrN3 from first principles

abstract:
  The electronic and magnetic structures of A2CrN3 (A = Ce, U) ternary
compounds calculated based on band magnetism within DFT exhibit different
behaviors of the nf elements (n = 4, 5 resp.). Charge analysis allows to
formally express the two compounds as A2Cr 5+ N3 5- thus classifying them as
covalent nitrides, i.e. far from formal exchange of +- 9 electrons. From
establishing the energy-volume equations of state, the two compounds are found
with hardness magnitudes: B0(A=Ce) =192 GPa and B0(A=U) = 243 GPa, within range
of oxides due to covalent metal-nitrogen bonding shown as based on overlap
matrix analysis. The uranium compound is harder due to a smaller volume and
less compressible U versus Ce metals. Ce2CrN3 exhibits large magnetization on
Cr (1.94BM) and a very small moment develops on cerium (0.14 BM) pointing out
to an intermediate valence state while in U2CrN3, M(Cr) = 0.49 BM and M(U) =
0.97BM. These results are stressed by broad band-like density of states (DOS)
behavior for A=U and localized DOS for A=Ce. Both compounds are found
ferromagnetic in the ground state


title: A Nearly Naked Supermassive Black Hole

abstract:
  During a systematic search for supermassive black holes (SMBHs) not in
galactic nuclei, we identified the compact symmetric radio source B3 1715+425
with an emission-line galaxy offset ~ 8.5 kpc from the nucleus of the brightest
cluster galaxy (BCG) in the redshift $z = 0.1754$ cluster ZwCl 8193. B3
1715+425 is too bright (brightness temperature $\sim 3 \times 10^{10}$ K at
observing frequency 7.6 GHz) and too luminous (1.4 GHz luminosity $\sim
10^{25}$ W/Hz) to be powered by anything but a SMBH, but its host galaxy is
much smaller ($\sim 0.9$ kpc $\times$ 0.6 kpc full width between half-maximum
points) and optically fainter (R-band absolute magnitude $\sim -18.2$) than any
other radio galaxy. Its high radial velocity $\sim 1860$ km/s relative to the
BCG, continuous ionized wake extending back to the BCG nucleus, and surrounding
debris indicate that the radio galaxy was tidally shredded passing through the
BCG core, leaving a nearly naked supermassive black hole fleeing from the BCG
with space velocity $> 2000$ km/s. The radio galaxy has mass $< 6 \times 10^9$
solar masses and infrared luminosity $\sim 3 \times 10^{11}$ solar luminosities
close to its dust Eddington limit, so it is vulnerable to further mass loss
from radiative feedback.


title: Universal hitting time statistics for integrable flows

abstract:
  The perceived randomness in the time evolution of "chaotic" dynamical systems
can be characterized by universal probabilistic limit laws, which do not depend
on the fine features of the individual system. One important example is the
Poisson law for the times at which a particle with random initial data hits a
small set. This was proved in various settings for dynamical systems with
strong mixing properties. The key result of the present study is that, despite
the absence of mixing, the hitting times of integrable flows also satisfy
universal limit laws which are, however, not Poisson. We describe the limit
distributions for "generic" integrable flows and a natural class of target
sets, and illustrate our findings with two examples: the dynamics in central
force fields and ellipse billiards. The convergence of the hitting time process
follows from a new equidistribution theorem in the space of lattices, which is
of independent interest. Its proof exploits Ratner's measure classification
theorem for unipotent flows, and extends earlier work of Elkies and McMullen.


title:
Bounds on the individual Betti numbers of complex varieties, stability
  and algorithms

abstract:
  We prove graded bounds on the individual Betti numbers of affine and
projective complex varieties. In particular, we give for each $p,d,r$, explicit
bounds on the $p$-th Betti numbers of affine and projective subvarieties of
$\mathrm{C}^k$, $\mathbb{P}^k_{\mathrm{C}}$, as well as products of projective
spaces, defined by $r$ polynomials of degrees at most $d$ as a function of
$p,d$ and $r$. Unlike previous bounds these bounds are independent of $k$, the
dimension of the ambient space. We also prove as consequences of our technique
certain homological and representational stability results for sequences of
complex projective varieties which could be of independent interest. Finally,
we highlight differences in computational complexities of the problem of
computing Betti numbers of complex as opposed to real projective varieties.


title: Use of Topology in physical problems

abstract:
  Some of the basic concepts of topology are explored through known physics
problems. This helps us in two ways, one, in motivating the definitions and the
concepts, and two, in showing that topological analysis leads to a clearer
understanding of the problem. The problems discussed are taken from classical
mechanics, quantum mechanics, statistical mechanics, solid state physics, and
biology (DNA), to emphasize some unity in diverse areas of physics. It is the
real Euclidean space, $R^d$, with which we are most familiar. Intuitions can
therefore be sharpened by appealing to the relevant features of this known
space, and by using these as simplest examples to illustrate the abstract
topological concepts. This is what is done in this chapter.


title: Scientific Realism and Primordial Cosmology

abstract:
  We discuss scientific realism from the perspective of modern cosmology,
especially primordial cosmology: i.e. the cosmological investigation of the
very early universe.
  We first (Section 2) state our allegiance to scientific realism, and discuss
what insights about it cosmology might yield, as against "just" supplying
scientific claims that philosophers can then evaluate. In particular, we
discuss: the idea of laws of cosmology, and limitations on ascertaining the
global structure of spacetime. Then we review some of what is now known about
the early universe (Section 3): meaning, roughly, from a thousandth of a second
after the Big Bang onwards(!).
  The rest of the paper takes up two issues about primordial cosmology, i.e.
the very early universe, where "very early" means, roughly, much earlier
(logarithmically) than one second after the Big Bang: say, less than $10^{-11}$
seconds. Both issues illustrate that familiar philosophical threat to
scientific realism, the under-determination of theory by data---on a cosmic
scale.
  The first issue (Section 4) concerns the difficulty of observationally
probing the very early universe. More specifically, the difficulty is to
ascertain details of the putative inflationary epoch. The second issue (Section
5) concerns difficulties about confirming a cosmological theory that postulates
a multiverse, i.e. a set of domains (universes) each of whose inhabitants (if
any) cannot directly observe, or otherwise causally interact with, other
domains. This again concerns inflation, since many inflationary models
postulate a multiverse.
  For all these issues, it will be clear that much remains unsettled, as
regards both physics and philosophy. But we will maintain that these remaining
controversies do not threaten scientific realism.


title:
Factorization Breaking of $A^T_d$ for polarized deuteron targets in a
  relativistic framework

abstract:
  We discuss the possible factorization of the tensor asymmetry $A^T_d$
measured for polarized deuteron targets within a relativistic framework. We
define a reduced asymmetry and find that factorization holds only in plane wave
impulse approximation and if p-waves are neglected. Our numerical results show
a strong factorization breaking once final state interactions are included. We
also compare the d-wave content of the wave functions with the size of the
factored, reduced asymmetry and find that there is no systematic relationship
of this quantity to the d-wave probability of the various wave functions.


title:
On Probabilistic Shaping of Quadrature Amplitude Modulation for the
  Nonlinear Fiber Channel

abstract:
  Different aspects of probabilistic shaping for a multi-span optical
communication system are studied. First, a numerical analysis of the additive
white Gaussian noise (AWGN) channel investigates the effect of using a small
number of input probability mass functions (PMFs) for a range of
signal-to-noise ratios (SNRs), instead of optimizing the constellation shaping
for each SNR. It is shown that if a small penalty of at most 0.1 dB SNR to the
full shaping gain is acceptable, just two shaped PMFs are required per
quadrature amplitude modulation (QAM) over a large SNR range. For a multi-span
wavelength division multiplexing (WDM) optical fiber system with 64QAM input,
it is shown that just one PMF is required to achieve large gains over uniform
input for distances from 1,400 km to 3,000 km. Using recently developed
theoretical models that extend the Gaussian noise (GN) model and full-field
split-step simulations, we illustrate the ramifications of probabilistic
shaping on the effective SNR after fiber propagation. Our results show that,
for a fixed average optical launch power, a shaping gain is obtained for the
noise contributions from fiber amplifiers and modulation-independent nonlinear
interference (NLI), whereas shaping simultaneously causes a penalty as it leads
to an increased NLI. However, this nonlinear shaping loss is found to have a
relatively minor impact, and optimizing the shaped PMF with a
modulation-dependent GN model confirms that the PMF found for AWGN is also a
good choice for a multi-span fiber system.


title: ENTRA: Whole-Systems Energy Transparency

abstract:
  Promoting energy efficiency to a first class system design goal is an
important research challenge. Although more energy-efficient hardware can be
designed, it is software that controls the hardware; for a given system the
potential for energy savings is likely to be much greater at the higher levels
of abstraction in the system stack. Thus the greatest savings are expected from
energy-aware software development, which is the vision of the EU ENTRA project.
This article presents the concept of energy transparency as a foundation for
energy-aware software development. We show how energy modelling of hardware is
combined with static analysis to allow the programmer to understand the energy
consumption of a program without executing it, thus enabling exploration of the
design space taking energy into consideration. The paper concludes by
summarising the current and future challenges identified in the ENTRA project.


title: Local analyses of Planck maps with Minkowski Functionals

abstract:
  Minkowski Functionals (MF) are excellent tools to investigate the statistical
properties of the cosmic background radiation (CMB) maps. Between their
notorious advantages is the possibility to use them efficiently in patches of
the CMB sphere, which allow studies in masked skies, inclusive analyses of
small sky regions. Then, possible deviations from Gaussianity are investigated
by comparison with MF obtained from a set of Gaussian isotropic simulated CMB
maps to which are applied the same cut-sky masks. These analyses are sensitive
enough to detect contaminations of small intensity like primary and secondary
CMB anisotropies. Our methodology uses the MF, widely employed to study
non-Gaussianities in CMB data, and asserts Gaussian deviations only when all of
them points out an exceptional $\chi^2$ value, at more than $2.2 \sigma$
confidence level, in a given sky patch. Following this rigorous procedure, we
find 13 regions in the foreground-cleaned Planck maps that evince such high
levels of non-Gaussian deviations. According to our results, these non-Gaussian
contributions show signatures that can be associated to the presence of hot or
cold spots in such regions. Moreover, some of these non-Gaussian deviations
signals suggest the presence of foreground residuals in those regions located
near the galactic plane. Additionally, we confirm that most of the regions
revealed in our analyses, but not all, have been recently reported in studies
done by the Planck collaboration. Furthermore, we also investigate whether
these non-Gaussian deviations can be possibly sourced by systematics, like
inhomogeneous noise and beam effect in the released Planck data, or perhaps due
to residual galactic foregrounds.


title: Calabi--Yau complete intersections in exceptional Grassmannians

abstract:
  We classify completely reducible equivariant vector bundles on Grassmannians
of exceptional Lie groups which give Calabi--Yau 3-folds as complete
intersections. In particular, we find a new family of Calabi--Yau 3-folds in an
$E_6$-Grassmannian.


title: Analysis and design of nonlinear resonances via singularity theory

abstract:
  Bifurcation theory and continuation methods are well-established tools for
the analysis of nonlinear mechanical systems subject to periodic forcing. We
illustrate the added value and the complementary information provided by
singularity theory with one distinguished parameter. While tracking
bifurcations reveals the qualitative changes in the behaviour, tracking
singularities reveals how structural changes are themselves organised in
parameter space. The complementarity of that information is demonstrated in the
analysis of detached resonance curves in a two-degree-of-freedom system.


title: Dynamo generated by the centrifugal instability

abstract:
  We present a new scenario for magnetic field amplification where an
electrically conducting fluid is confined in a differentially rotating,
spherical shell with thin aspect-ratio. When the angular momentum sufficiently
decreases outwards, an hydrodynamic instability develops in the equatorial
region, characterised by pairs of counter-rotating toroidal vortices similar to
those observed in cylindrical Couette flow. These spherical Taylor-Couette
vortices generate a subcritical dynamo magnetic field dominated by
non-axisymmetric components. We show that the critical magnetic Reynolds number
seems to reach a constant value at large Reynolds number and that the global
rotation can strongly decrease the dynamo onset. Our numerical results are
understood within the framework of a simple dynamical system, and we propose a
low-dimensional model for subcritical dynamo bifurcations. Implications for
both laboratory dynamos and astrophysical magnetic fields are finally
discussed.


title:
Fifth-order susceptibility unveils growth of thermodynamic amorphous
  order in glass-formers

abstract:
  Glasses are ubiquitous in daily life and technology. However the microscopic
mechanisms generating this state of matter remain subject to debate: Glasses
are considered either as merely hyper-viscous liquids or as resulting from a
genuine thermodynamic phase transition towards a rigid state. We show that
third- and fifth-order susceptibilities provide a definite answer to this
longstanding controversy. Performing the corresponding high-precision nonlinear
dielectric experiments for supercooled glycerol and propylene carbonate, we
find strong support for theories based upon thermodynamic amorphous order.
Moreover, when lowering temperature, we find that the growing transient domains
are compact - that is their fractal dimension d_f = 3. The glass transition may
thus represent a class of critical phenomena different from canonical
second-order phase transitions for which d_f < 3.


title: Matching Networks for One Shot Learning

abstract:
  Learning from a few examples remains a key challenge in machine learning.
Despite recent advances in important domains such as vision and language, the
standard supervised deep learning paradigm does not offer a satisfactory
solution for learning new concepts rapidly from little data. In this work, we
employ ideas from metric learning based on deep neural features and from recent
advances that augment neural networks with external memories. Our framework
learns a network that maps a small labelled support set and an unlabelled
example to its label, obviating the need for fine-tuning to adapt to new class
types. We then define one-shot learning problems on vision (using Omniglot,
ImageNet) and language tasks. Our algorithm improves one-shot accuracy on
ImageNet from 87.6% to 93.2% and from 88.0% to 93.8% on Omniglot compared to
competing approaches. We also demonstrate the usefulness of the same model on
language modeling by introducing a one-shot task on the Penn Treebank.


title:
Graph-Community Detection for Cross-Document Topic Segment Relationship
  Identification

abstract:
  In this paper we propose a graph-community detection approach to identify
cross-document relationships at the topic segment level. Given a set of related
documents, we automatically find these relationships by clustering segments
with similar content (topics). In this context, we study how different
weighting mechanisms influence the discovery of word communities that relate to
the different topics found in the documents. Finally, we test different mapping
functions to assign topic segments to word communities, determining which topic
segments are considered equivalent.
  By performing this task it is possible to enable efficient multi-document
browsing, since when a user finds relevant content in one document we can
provide access to similar topics in other documents. We deploy our approach in
two different scenarios. One is an educational scenario where equivalence
relationships between learning materials need to be found. The other consists
of a series of dialogs in a social context where students discuss commonplace
topics. Results show that our proposed approach better discovered equivalence
relationships in learning material documents and obtained close results in the
social speech domain, where the best performing approach was a clustering
technique.


title: Bayesian estimation of incompletely observed diffusions

abstract:
  We present a general framework for Bayesian estimation of incompletely
observed multivariate diffusion processes. Observations are assumed to be
discrete in time, noisy and incomplete. We assume the drift and diffusion
coefficient depend on an unknown parameter. A data-augmentation algorithm for
drawing from the posterior distribution is presented which is based on
simulating diffusion bridges conditional on a noisy incomplete observation at
an intermediate time. The dynamics of such filtered bridges are derived and it
is shown how these can be simulated using a generalised version of the guided
proposals introduced in Schauer et al. (2016).


title: Role of the plurality rule in multiple choices

abstract:
  People are often challenged to select one among several alternatives. This
situation is present not only in decisions about complex issues, e.g.,
political or academic choices, but also about trivial ones, as in daily
purchases at a supermarket. We tackle this scenario by means of the tools of
statistical mechanics. Following this approach, we introduce and analyze a
model of opinion dynamics, using a Potts-like state variable to represent the
multiple choices, including the ``undecided state'', that represents the
individuals that do not make a choice. We investigate the dynamics over
Erd\"{o}s-R\'enyi and Barab\'asi-Albert networks, two paradigmatic classes with
the small-world property, and we show the impact of the type of network on the
opinion dynamics. Depending on the number of available options $q$ and on the
degree distribution of the network of contacts, different final steady states
are accessible: from a wide distribution of choices to a state where a given
option largely dominates. The abrupt transition between them is consistent with
the sudden viral dominance of a given option over many similar ones. Moreover,
the probability distributions produced by the model are validated by real data.
Finally, we show that the model also contemplates the real situation of
overchoice, where a large number of similar alternatives makes the choice
process harder and indecision prevail.


title: Bounds on Universal Extra Dimension from LHC Run I and II data

abstract:
  We discuss the collider bounds on minimal Universal Extra Dimension (mUED)
model from LHC Run-I and II data. The phenomenology of mUED is determined by
only two parameters namely, the compactification scale ($R^{-1}$) of the extra
dimension and cutoff scale ($\Lambda$) of the theory. The characteristic
feature of mUED is the occurrence of nearly degenerate mass spectrum for the
Kaluza-Klein (KK) particles and hence, soft leptons, soft jets at the collider
experiments. The degree of degeneracy of KK-mass spectrum crucially depends on
$\Lambda$. The strongest direct bound on $R^{-1}$ ($\sim $950 GeV for large
$\Lambda$) arises from a search for a pair of soft dimuons at the Large Hadron
Collider (LHC) experiment with 8 TeV center-of-mass energy and $20~{\rm
fb}^{-1}$ integrated luminosity. However, for small $\Lambda$ and hence, small
splitting within the first KK-level, the bounds from the dimuon channel is
rather weak. On the other hand, the discovery of 126 GeV Higgs boson demands
small $\Lambda$ to prevent the scalar potential form being unbounded from
below. We discuss LHC monojet searches as a probe of low $\Lambda$ region of
mUED parameter space. We also compute bounds on the mUED parameter space from
13 TeV multijets results.


title: Tensor surgery and tensor rank

abstract:
  We introduce a method for transforming low-order tensors into higher-order
tensors and apply it to tensors defined by graphs and hypergraphs. The
transformation proceeds according to a surgery-like procedure that splits
vertices, creates and absorbs virtual edges and inserts new vertices and edges.
We show that tensor surgery is capable of preserving the low rank structure of
an initial tensor decomposition and thus allows to prove nontrivial upper
bounds on tensor rank, border rank and asymptotic rank of the final tensors. We
illustrate our method with a number of examples. Tensor surgery on the triangle
graph, which corresponds to the matrix multiplication tensor, leads to
nontrivial rank upper bounds for all odd cycle graphs, which correspond to the
tensors of iterated matrix multiplication. In the asymptotic setting we obtain
upper bounds in terms of the matrix multiplication exponent $\omega$ and the
rectangular matrix multiplication parameter $\alpha$. These bounds are optimal
if $\omega$ equals two. We also give examples that illustrate that tensor
surgery on general graphs might involve the absorption of virtual hyperedges
and we provide an example of tensor surgery on a hypergraph. Besides its
relevance in algebraic complexity theory, our work has applications in quantum
information theory and communication complexity.


title:
Inference in Regression Discontinuity Designs with a Discrete Running
  Variable

abstract:
  We consider inference in regression discontinuity designs when the running
variable only takes a moderate number of distinct values. In particular, we
study the common practice of using confidence intervals (CIs) based on standard
errors that are clustered by the running variable as a means to make inference
robust to model misspecification (Lee and Card, 2008). We derive theoretical
results and present simulation and empirical evidence showing that these CIs do
not guard against model misspecification, and that they have poor coverage
properties. We therefore recommend against using these CIs in practice. We
instead propose two alternative CIs with guaranteed coverage properties under
easily interpretable restrictions on the conditional expectation function.


title: Networked Intelligence: Towards Autonomous Cyber Physical Systems

abstract:
  Developing intelligent systems requires combining results from both industry
and academia. In this report you find an overview of relevant research fields
and industrially applicable technologies for building very large scale cyber
physical systems. A concept architecture is used to illustrate how existing
pieces may fit together, and the maturity of the subsystems is estimated.
  The goal is to structure the developments and the challenge of machine
intelligence for Consumer and Industrial Internet technologists, cyber physical
systems researchers and people interested in the convergence of data & Internet
of Things. It can be used for planning developments of intelligent systems.


title: Fundamental groups of $F$-regular singularities via $F$-signature

abstract:
  We prove that the local etale fundamental group of a strongly $F$-regular
singularity is finite (and likewise for the \'etale fundamental group of the
complement of a codimension $\geq 2$ set), analogous to results of Xu and
Greb-Kebekus-Peternell for KLT singularities in characteristic zero. In fact
our result is effective, we show that the reciprocal of the $F$-signature of
the singularity gives a bound on the size of this fundamental group. To prove
these results and their corollaries, we develop new transformation rules for
the $F$-signature under finite etale-in-codimension-one extensions. As another
consequence of these transformation rules, we also obtain purity of the branch
locus over rings with mild singularities (particularly if the $F$-signature is
$> 1/2$). Finally, we generalize our $F$-signature transformation rules to the
context of pairs and not-necessarily etale-in-codimension-one extensions,
obtaining an analog of another result of Xu.


title:
Observation of Spatial Charge and Spin Correlations in the 2D
  Fermi-Hubbard Model

abstract:
  Strong electron correlations lie at the origin of transformative phenomena
such as colossal magneto-resistance and high-temperature superconductivity.
Already near room temperature, doped copper oxide materials display remarkable
features such as a pseudo-gap and a "strange metal" phase with unusual
transport properties. The essence of this physics is believed to be captured by
the Fermi-Hubbard model of repulsively interacting, itinerant fermions on a
lattice. Here we report on the site-resolved observation of charge and spin
correlations in the two-dimensional (2D) Fermi-Hubbard model realized with
ultracold atoms. Antiferromagnetic spin correlations are maximal at
half-filling and weaken monotonically upon doping. Correlations between singly
charged sites are negative at large doping, revealing the Pauli and correlation
hole\textemdash a suppressed probability of finding two fermions near each
other. However, as the doping is reduced below a critical value, correlations
between such local magnetic moments become positive, signaling strong bunching
of doublons and holes. Excellent agreement with numerical linked-cluster
expansion (NLCE) and determinantal quantum Monte Carlo (DQMC) calculations is
found. Positive non-local moment correlations directly imply potential energy
fluctuations due to doublon-hole pairs, which should play an important role for
transport in the Fermi-Hubbard model.


title:
The Evolution of the Fractions of Quiescent and Star-forming Galaxies as
  a Function of Stellar Mass Since z=3: Increasing Importance of Massive, Dusty
  Star-forming Galaxies in the Early Universe

abstract:
  Using the UltraVISTA DR1 and 3D-HST catalogs, we construct a
stellar-mass-complete sample, unique for its combination of surveyed volume and
depth, to study the evolution of the fractions of quiescent galaxies,
moderately unobscured star-forming galaxies, and dusty star-forming galaxies as
a function of stellar mass over the redshift interval $0.2 \le z \le 3.0$. We
show that the role of dusty star-forming galaxies within the overall galaxy
population becomes more important with increasing stellar mass, and grows
rapidly with increasing redshift. Specifically, dusty star-forming galaxies
dominate the galaxy population with $\log{(M_{\rm star}/M_{\odot})} \gtrsim
10.3$ at $z\gtrsim2$. The ratio of dusty and non-dusty star-forming galaxies as
a function of stellar mass changes little with redshift. Dusty star-forming
galaxies dominate the star-forming population at $\log{(M_{\rm
star}/M_{\odot})} \gtrsim 10.0-10.5$, being a factor of $\sim$3-5 more common,
while unobscured star-forming galaxies dominate at $\log{(M_{\rm
star}/M_{\odot})} \lesssim 10$. At $\log{(M_{\rm star}/M_{\odot})} > 10.5$, red
galaxies dominate the galaxy population at all redshift $z<3$, either because
they are quiescent (at late times) or dusty star-forming (in the early
universe).


title:
7.1 keV sterile neutrino constraints from X-ray observations of 33
  clusters of galaxies with Chandra ACIS

abstract:
  Recently an unidentified emission line at 3.55 keV has been detected in X-ray
spectra of clusters of galaxies. The line has been discussed as a possible
decay signature of 7.1 keV sterile neutrinos, which have been proposed as a
dark matter candidate. We aim at putting constraints on the proposed line
emission in a large sample of Chandra-observed clusters and obtain limits on
the mixing-angle in a 7.1 keV sterile neutrino dark matter scenario. For a
sample of 33 high-mass clusters of galaxies we merge all observations from the
Chandra data archive. Each cluster has more than 100 ks of combined exposure.
The resulting high signal-to-noise spectra are used to constrain the flux of an
unidentified line emission at 3.55 keV in the individual spectra and a merged
spectrum of all clusters. We obtained very detailed spectra around the 3.55 keV
range and limits on an unidentified emission line. Assuming all dark matter
were made of 7.1 keV sterile neutrinos the upper limits on the mixing angle are
$\rm{sin^2(2\Theta)}$ $\rm{<10.1\times10^{-11}}$ from ACIS-I, and
$\rm{<40.3\times10^{-11}}$ from ACIS-S data at 99.7 per cent confidence level.
We do not find evidence for an unidentified emission line at 3.55 keV. The
sample extends the list of objects searched for an emission line at 3.55 keV
and will help to identify the best targets for future studies of the potential
dark matter decay line with upcoming X-ray observatories like Hitomi (Astro-H),
eROSITA, and Athena.


title: Hiding its age: the case for a younger bulge

abstract:
  The determination of the age of the bulge has led to two contradictory
results. On the one side, the color-magnitude diagrams in different bulge
fields seem to indicate a uniformly old ($>$10 Gyr) population. On the other
side, individual ages derived from dwarfs observed through microlensing events
seem to indicate a large spread, from $\sim$ 2 to $\sim$ 13 Gyr. Because the
bulge is now recognised as being mainly a boxy peanut-shaped bar, it is
suggested that disk stars are one of its main constituents, and therefore also
stars with ages significantly younger than 10 Gyr. Other arguments as well
point to the fact that the bulge cannot be exclusively old, and in particular
cannot be a burst population, as it is usually expected if the bulge was the
fossil remnant of a merger phase in the early Galaxy. In the present study, we
show that given the range of metallicities observed in the bulge, a uniformly
old population would be reflected into a significant spread in color at the
turn-off which is not observed. Inversely, we demonstrate that the correlation
between age and metallicity expected to hold for the inner disk would conspire
to form a color-magnitude diagram with a remarkably small spread in color, thus
mimicking the color-magnitude diagram of a uniformly old population. If stars
younger than 10 Gyr are part of the bulge, as must be the case if the bulge has
been mainly formed through dynamical instabilities in the disk, then a very
small spread at the turn-off is expected, as seen in the observations.


title:
Search for resonant production of high-mass photon pairs in
  proton-proton collisions at sqrt(s) = 8 and 13 TeV

abstract:
  A search for the resonant production of high-mass photon pairs is presented.
The analysis is based on samples of proton-proton collision data collected by
the CMS experiment at center-of-mass energies of 8 and 13 TeV, corresponding to
integrated luminosities of 19.7 and 3.3 inverse femtobarns, respectively. The
search focuses on spin-0 and spin-2 resonances with masses between 0.5 and 4
TeV and with widths, relative to the mass, between 1.4E-4 and 5.6E-2. Limits
are set on scalar resonances produced through gluon-gluon fusion, and on
Randall-Sundrum gravitons. A modest excess of events compatible with a narrow
resonance with a mass of about 750 GeV is observed. The local significance of
the excess is approximately 3.4 standard deviations. The significance is
reduced to 1.6 standard deviations once the effect of searching under multiple
signal hypotheses is considered. More data are required to determine the origin
of this excess.


title:
Conetronics in 2D Metal-Organic Frameworks: Double Dirac Cones, Magnetic
  Half Dirac Cones and Quantum Anomalous Hall Effect

abstract:
  Based on recently synthesized Ni3C12S12 class 2D metal-organic frameworks, we
predict electronic properties of M3C12S12 and M3C12O12, where M is Zn, Cd, Hg,
Be, or Mg with no M orbital contributions to bands near Fermi level. For
M3C12S12, their band structures exhibit double Dirac cones with different Fermi
velocities that are n and p type, respectively, which are switchable by
few-percent strain. The crossing of two cones are symmetry-protected to be
non-hybridizing, leading to two independent channels in 2D node-line semimetals
at the same k-point akin to spin-channels in spintronics, rendering conetronics
device possible. The node line rings right at their crossing, which are both
electron and hole pockets at the Fermi level, can give rise to
magnetoresistance that will not saturate when the magnetic field is infinitely
large, due to perfect n-p compensation. For M3C12O12, together with conjugated
metal-tricatecholate polymers M3(HHTP)2, the spin-polarized slow Dirac cone
center is pinned precisely at the Fermi level, making the systems conducting in
only one spin or cone channel. Quantum anomalous Hall effect can arise in MOFs
with non-negligible spin-orbit coupling like Cu3C12O12. Compounds of M3C12S12
and M3C12O12 with different M, can be used to build spintronic and
cone-selecting heterostructure devices, tunable by strain or electrostatic
gating.