title: Quantum Non-Gaussian Multiphoton Light

abstract:
  We propose an experimental method of recognizing quantum non-Gaussian
multiphoton states. This is a native quantum property of Fock states, the
fundamental quantum states with a constant number of particles. Our method
allows experimental development and characterization of higher Fock states of
light, reaching even beyond the current technical limits of their generation.
We experimentally demonstrate that it is capable of distinguishing realistic
quantum non-Gaussian light with the mean number of photons up to 5 despite
detection efficiency of 50 %. We also provide evidence that our method can help
to distinguish the number of single-photon emitters based only on their
collective emission.


title: Convex projective generalized Dehn filling

abstract:
  For $d=4, 5, 6$, we exhibit the first examples of complete finite volume
hyperbolic $d$-manifolds $M$ with cusps such that infinitely many $d$-orbifolds
$M_{m}$ obtained from $M$ by generalized Dehn filling admit properly convex
real projective structures. The orbifold fundamental groups of $M_m$ are
Gromov-hyperbolic relative to a collection of subgroups virtually isomorphic to
$\mathbb{Z}^{d-2}$, hence the images of the developing maps of the projective
structures on $M_m$ are new examples of divisible properly convex domains of
the projective $d$-space which are not strictly convex, in contrast to the
previous examples of Benoist.


title: A Greedy Approach to Answer Reachability Queries on DAGs

abstract:
  Several modern applications involve huge graphs and require fast answers to
reachability queries. In more than two decades since first proposals, several
approaches have been presented adopting on-line searches, hop labelling or
transitive closure compression. Transitive closure compression techniques
usually construct a graph reachability index, for example by decomposing the
graph into disjoint chains. As memory consumption is proportional to the number
of chains, the target of those algorithms is to decompose the graph into an
optimal number \width\ of chains. However, commonly used techniques fail to
meet general expectations, are exceedingly complex, and their application on
large graphs is impractical. The main contribution of this paper is a novel
approach to construct such reachability indexes. The proposed method decomposes
the graph into a sub-optimal number $\widehat{c}$ of chains by following a
greedy strategy. We show that, given a vertex topological order, such a
decomposition is obtained in $\mathcal{O}(\widehat{c} m)$ time, and requires
$\mathcal{O}(\widehat{c} n)$ space, with $\widehat{c}$ bounded by $[c
\log(\frac{n}{c})]$. We provide experimental evidence suggesting that, on
different categories of automatically generated benchmarks as well as on graphs
arising from the field of logic synthesis and formal verification, the proposed
method produces a number of chains very close to the optimum, while
significantly reducing computation time.


title: A note on sphere free energy of $p$-form gauge theory and Hodge duality

abstract:
  We consider a free $p$-form gauge theory on a $d$-dimensional sphere of
radius $R$ and calculate its free energy. We perform the calculation for
generic values of $p$ and obtain the free energy as a function of $d, p$ and
$R$. The result contains a $\log R$ term with coefficient proportional to
$\left(2p+2-d \right)$, which is consistent with lack of conformal invariance
for $p$ form theories in dimensions other than $2p+2$. We also compare the
result for $p$-form and $(d-p-2)$-form theory which are classically Hodge dual
to each other in $d$ dimensions and find that they agree for odd values of $d$.
Instead, for even $d$, we find that the results disagree by an amount that is
consistent with the reported values in the literature.


title: What Makes a Link Successful on Wikipedia?

abstract:
  While a plethora of hypertext links exist on the Web, only a small amount of
them are regularly clicked. Starting from this observation, we set out to study
large-scale click data from Wikipedia in order to understand what makes a link
successful. We systematically analyze effects of link properties on the
popularity of links. By utilizing mixed-effects hurdle models supplemented with
descriptive insights, we find evidence of user preference towards links leading
to the periphery of the network, towards links leading to semantically similar
articles, and towards links in the top and left-side of the screen. We
integrate these findings as Bayesian priors into a navigational Markov chain
model and by doing so successfully improve the model fits. We further adapt and
improve the well-known classic PageRank algorithm that assumes random
navigation by accounting for observed navigational preferences of users in a
weighted variation. This work facilitates understanding navigational click
behavior and thus can contribute to improving link structures and algorithms
utilizing these structures.


title:
Radial velocities and metallicities of red giant stars in the old open
  cluster NGC 7762

abstract:
  We present and discuss radial velocity and the very first metallicity
measurements for nine evolved stars in the poorly known old open cluster NGC
7762. We isolated eight radial velocity cluster members and one interloper.
Radial velocities are in good agreement with previous studies. NGC 7762 turns
out to be of solar metallicity within the uncertainties ([Fe/H]=0.04$\pm$0.12).
For this metallicity, the cluster age is 2.5$\pm$0.2 Gyr, and falls in a age
range where only a few old open clusters are known. With respect to previous
studies, we find a larger distance, implying the cluster to be located at
900$^{+70}_{-50}$ pc from the Sun. For most of the elements we measure
solar-scaled abundance ratios. We searched the literature for open clusters of
similar age in the solar vicinity and found that NGC 7762 can be considered a
twin of Ruprecht 147, a similar age cluster located at only 300 pc from the
Sun. In fact, beside age, also metallicity and abundance ratios are very close
to Ruprecht 147 values within the observational uncertainties.


title:
2D MoS2-Graphene-based multilayer van der Waals heterostructures:
  Enhanced charge transfer and optical absorption, and electric-field tunable
  Dirac point and band gap

abstract:
  Multilayer van der Waals (vdWs) heterostructures assembled by diverse
atomically thin layers have demonstrated a wide range of fascinating phenomena
and novel applications. Understanding the interlayer coupling and its
correlation effect is paramount for designing novel vdWs heterostructures with
desirable physical properties. Using a detailed theoretical study of 2D
MoS2-graphene (GR)-based heterostructures based on state-of-the-art hybrid
density functional theory, we reveal that for 2D few-layer heterostructures,
vdWs forces between neighboring layers depend on the number of layers. Compared
to that in bilayer, the interlayer coupling in trilayer vdW heterostructures
can significantly be enhanced by stacking the third layer, directly supported
by short interlayer separations and more interfacial charge transfer. The
trilayer shows strong light absorption over a wide range (<700 nm), making it
very potential for solar energy harvesting and conversion. Moreover, the Dirac
point of GR and band gaps of each layer and trilayer can be readily tuned by
external electric field, verifying multilayer vdWs heterostructures with unqiue
optoelectronic properties found by experiments. These results suggest that
tuning the vdWs interaction, as a new design parameter, would be an effective
strategy for devising particular 2D multilayer vdWs heterostructures to meet
the demands in various applications.


title:
Stochastic multi-reference perturbation theory with application to
  linearized coupled cluster method

abstract:
  In this article we report a stochastic evaluation of the recently proposed
LCC multireference perturbation theory [Sharma S., and Alavi A., J. Chem. Phys.
143, 102815, (2015)]. In this method both the zeroth order and first order
wavefunctions are sampled stochastically by propagating simultaneously two
populations of signed walkers. The sampling of the zeroth order wavefunction
follows a set of stochastic processes identical to the one used in the FCIQMC
method. To sample the first order wavefunction, the usual FCIQMC algorithm is
augmented with a source term that spawns walkers in the sampled first order
wavefunction from the zeroth order wavefunction. The second order energy is
also computed stochastically but requires no additional overhead outside of the
added cost of sampling the first order wavefunction. This fully stochastic
method opens up the possibility of simultaneously treating large active spaces
to account for static correlation and recovering the dynamical correlation
using perturbation theory. This method is used to study a few benchmark systems
including the carbon dimer and aromatic molecules. We have computed the
singlet-triplet gaps of benzene and m-xylylene. For m-xylylene, which has
proved difficult for standard CASSCF+PT, we find the singlet-triplet gap to be
in good agreement with the experimental values.


title: Cognitive Discriminative Mappings for Rapid Learning

abstract:
  Humans can learn concepts or recognize items from just a handful of examples,
while machines require many more samples to perform the same task. In this
paper, we build a computational model to investigate the possibility of this
kind of rapid learning. The proposed method aims to improve the learning task
of input from sensory memory by leveraging the information retrieved from
long-term memory. We present a simple and intuitive technique called cognitive
discriminative mappings (CDM) to explore the cognitive problem. First, CDM
separates and clusters the data instances retrieved from long-term memory into
distinct classes with a discrimination method in working memory when a sensory
input triggers the algorithm. CDM then maps each sensory data instance to be as
close as possible to the median point of the data group with the same class.
The experimental results demonstrate that the CDM approach is effective for
learning the discriminative features of supervised classifications with few
training sensory input instances.


title: Tilted disordered Weyl semimetals

abstract:
  Although Lorentz invariance forbids the presence of a term that tilts the
energy-momentum relation in the Weyl Hamiltonian, a tilted dispersion is not
forbidden and, in fact, generic for condensed matter realizations of Weyl
semimetals. We here investigate the combined effect of such a tilted Weyl
dispersion and the presence of potential disorder. In particular, we address
the influence of a tilt on the disorder-induced phase transition between a
quasi-ballistic phase at weak disorder, in which the disorder is an irrelevant
perturbation, and a diffusive phase at strong disorder. Our main result is that
the presence of a tilt leads to a reduction of the critical disorder strength
for this transition or, equivalently, that increasing the tilt at fixed
disorder strength drives the system through the phase transition to the
diffusive strong-disorder phase. Notably this obscures the tilt induced
Lifshitz transition to an over tilted type-II Weyl phase at any finite disorder
strength. Our results are supported by analytical calculations using the
self-consistent Born approximation and numerical calculations of the density of
states and of transport properties.


title:
Estimation of the Perturbing Accelerations Induced on the LARES
  Satellite by Neutral Atmosphere Drag

abstract:
  The laser-ranged satellite LARES is expected to provide new refined
measurements of relativistic physics, as well as significant contributions to
space geodesy and geophysics. The very low area-to-mass ratio of this passive
and dense satellite was chosen to reduce as much as possible the disturbing
effects of non-gravitational perturbations. However, because of its height,
about 1450 km compared with about 5800-5900 km for the two LAGEOS satellites,
LARES is exposed to a much stronger drag due to neutral atmosphere. From a
precise orbit determination, analyzing the laser ranging normal points of LARES
over a time span of about 3.7 years, it was found an average semi-major axis
decay rate of -0.999 m per year, corresponding to a non-conservative net force
with a mean along-track acceleration of -1.444 x 10^-11 m/s^2. By means of a
modified version of the SATRAP (ISTI/CNR) code, the neutral drag perturbation
acting on LARES was evaluated over the same time span, taking into account the
real evolution of solar and geomagnetic activities, with five thermospheric
density models. All of them were able to model most of the observed semi-major
axis decay, with differences among the average drag coefficients smaller than
10%. A further independent check carried out analyzing the orbital decay of a
passive spherical satellite (Ajisai) just 40 km higher than LARES, it was then
concluded that some of the currently best models developed for neutral
atmosphere, within their uncertainties and range of applicability, were able to
account for most (about 98.6%) of the observed semi-major axis decay of LARES.
Finally, after modeling the neutral atmosphere drag, a residual semi-major axis
decay, corresponding to an average along-track acceleration of about -2 x
10^-13 m/s^2 (i.e. about 1/72 of neutral drag), was detected as well.


title: Quantum key distribution without the wavefunction

abstract:
  A well-known feature of quantum mechanics is the secure exchange of secret
bit strings which can then be used as keys to encrypt messages transmitted over
any classical communication channel. It is demonstrated that this quantum key
distribution allows a much more general and abstract access than commonly
thought. The results include some generalizations for the Hilbert space version
of quantum key distribution,but base upon a general non-classical extension of
conditional probability. A special state-independent conditional probability is
identified as origin of the superior security of quantum key distribution and
may have more profound implications for the foundations and interpretation of
quantum mechanics,quantum information theory, and the philosophical question
what actually constitutes physical reality.


title: Tailored Mutants Fit Bugs Better

abstract:
  Mutation analysis measures test suite adequacy, the degree to which a test
suite detects seeded faults: one test suite is better than another if it
detects more mutants. Mutation analysis effectiveness rests on the assumption
that mutants are coupled with real faults i.e. mutant detection is strongly
correlated with real fault detection. The work that validated this also showed
that a large portion of defects remain out of reach.
  We introduce tailored mutation operators to reach and capture these defects.
Tailored mutation operators are built from and apply to an existing codebase
and its history. They can, for instance, identify and replay errors specific to
the project for which they are tailored. As our point of departure, we define
tailored mutation operators for identifiers, which mutation analysis has
largely ignored, because there are too many ways to mutate them. Evaluated on
the Defects4J dataset, our new mutation operators creates mutants coupled to
14% more faults, compared to traditional mutation operators.
  These new mutation operators, however, quadruple the number of mutants. To
combat this problem, we propose a new approach to mutant selection focusing on
the location at which to apply mutation operators and the unnaturalness of the
mutated code. The results demonstrate that the location selection heuristics
produce mutants more closely coupled to real faults for a given budget of
mutation operator applications.
  In summary, this paper defines and explores tailored mutation operators,
advancing the state of the art in mutation testing in two ways: 1) it suggests
mutation operators that mutate identifiers and literals, extending mutation
analysis to a new class of faults and 2) it demonstrates that selecting the
location where a mutation operator is applied decreases the number of generated
mutants without affecting the coupling of mutants and real faults.


title:
Visualising three-dimensional volumetric data with an arbitrary
  coordinate system

abstract:
  Astronomical data does not always use Cartesian coordinates. Both all-sky
observational data and simulations of rotationally symmetric systems, such as
accretion and protoplanetary discs, may use spherical polar or other coordinate
systems. Standard displays rely on Cartesian coordinates, but converting
non-Cartesian data into Cartesian format causes distortion of the data and loss
of detail. I here demonstrate a method using standard techniques from computer
graphics that avoids these problems with 3D data in arbitrary coordinate
systems. The method adds minimum computational cost to the display process and
is suitable for both realtime, interactive content and producing fixed rendered
images and videos. Proof-of-concept code is provided which works for data in
spherical polar coordinates.


title:
Observer design for piecewise smooth and switched systems via
  contraction theory

abstract:
  The aim of this paper is to present the application of an approach to study
contraction theory recently developed for piecewise smooth and switched
systems. The approach that can be used to analyze incremental stability
properties of so-called Filippov systems (or variable structure systems) is
based on the use of regularization, a procedure to make the vector field of
interest differentiable before analyzing its properties. We show that by using
this extension of contraction theory to nondifferentiable vector fields, it is
possible to design observers for a large class of piecewise smooth systems
using not only Euclidean norms, as also done in previous literature, but also
non-Euclidean norms. This allows greater flexibility in the design and
encompasses the case of both piecewise-linear and piecewise-smooth (nonlinear)
systems. The theoretical methodology is illustrated via a set of representative
examples.


title: Coherence in quantum estimation

abstract:
  The geometry of quantum states provides a unifying framework for estimation
processes based on quantum probes, and it allows to derive the ultimate bounds
of the achievable precision. We show a relation between the statistical
distance between infinitesimally close quantum states and the second order
variation of the coherence of the optimal measurement basis with respect to the
state of the probe. In Quantum Phase Estimation protocols, this leads to
identify coherence as the relevant resource that one has to engineer and
control to optimize the estimation precision. Furthermore, the main object of
the theory i.e., the Symmetric Logarithmic Derivative, in many cases allows to
identify a proper factorization of the whole Hilbert space in two subsystems.
The factorization allows: to discuss the role of coherence vs correlations in
estimation protocols; to show how certain estimation processes can be
completely or effectively described within a single-qubit subsystem; and to
derive lower bounds for the scaling of the estimation precision with the number
of probes used. We illustrate how the framework works for both noiseless and
noisy estimation procedures, in particular those based on multi-qubit
GHZ-states. Finally we succinctly analyze estimation protocols based on
zero-temperature critical behaviour. We identify the coherence that is at the
heart of their efficiency, and we show how it exhibits the non-analyticities
and scaling behaviour proper of a large class of quantum phase transitions.


title:
Experimental simulation of next-nearest-neighbor Heisenberg chain with
  photonic crystal waveguide array

abstract:
  Next-nearest-neighbor Heisenberg chain plays important roles in solid state
physics, such as predicting exotic electric properties of two-dimensional
materials or magnetic properties of organic compounds. Direct experimental
studies of the many-body electron systems or spin systems associating to these
materials are challenging tasks, while optical simulation provides an effective
and economical way for immediate observation. Comparing with bulk optics,
integrated optics are more of fascinating for steady, large scale and long-time
evolution simulations. Photonic crystal is an artificial microstructure
material with multiple methods to tune the propagation properties, which are
essential for various simulation tasks. Here we report for the first time an
experimental simulation of next-nearest-neighbor Heisenberg chain with an
integrated optical chip of photonic crystal waveguide array. The use of
photonic crystal enhances evanescent field thus allows coupling between
next-nearest-neighbor waveguides in such a planar waveguide array, without
breaking the weak coupling condition of the coupled mode equation.
Particularly, similarities between the model and coherent light propagation
could reach 0.99 in numerical simulations and 0.89 in experiment. Localization
effect induced by second-order coupling and coupling strengthening with
increasing wavelengths were also revealed in both numerical simulations and
experiments. The platform proposed here is compatible with mature complementary
metal oxide semiconductor technology thus possesses the potential for
larger-scale problems and photonic crystals further allows simulations of
specific target Hamiltonians.


title:
The inviscid Burgers equation with fractional Brownian initial data: the
  dimension of regular Lagrangian points

abstract:
  Fractional Brownian motion, H-FBM , of index 0<H<1 is considered as initial
velocity in the inviscid Burgers equation. It is shown that the Hausdorff
dimension of regular Lagrangian points at any moment t is equal to H. This fact
validates the Sinai-Frisch conjecture known since 1992.


title: Conductance distribution near the Anderson transition

abstract:
  Using a modification of the Shapiro approach, we introduce the two-parameter
family of conductance distributions W(g), defined by simple differential
equations, which are in the one-to-one correspondence with conductance
distributions for quasi-one-dimensional systems of size L^{d-1}\times L_z,
characterizing by parameters L/\xi and L_z/L (\xi is the correlation length, d
is the dimension of space). This family contains the Gaussian and log-normal
distributions, typical for the metallic and localized phases. For a certain
choice of parameters, we reproduce the results for the cumulants of conductance
in the space dimension d=2+\epsilon obtained in the framework of the
\sigma-model approach. The universal property of distributions is existence of
two asymptotic regimes, log-normal for small g and exponential for large g. In
the metallic phase they refer to remote tails, in the critical region they
determine practically all distribution, in the localized phase the former
asymptotics forces out the latter. A singularity at g=1, discovered in
numerical experiments, is admissible in the framework of their calculational
scheme, but related with a deficient definition of conductance. Apart of this
singularity, the critical distribution for d=3 is well described by the present
theory. One-parameter scaling for the whole distribution takes place under
condition, that two independent parameters characterizing this distribution are
functions of the ratio L/\xi.


title:
Coupled spin-1/2 ladders as microscopic models for non-Abelian chiral
  spin liquids

abstract:
  We construct a two-dimensional (2D) lattice model that is argued to realize a
gapped chiral spin liquid with (Ising) non-Abelian topological order. The
building blocks are spin-1/2 two-leg ladders with $SU(2)$-symmetric spin-spin
interactions. The two-leg ladders are then arranged on rows and coupled through
SU(2)-symmetric interactions between consecutive ladders. The intra-ladder
interactions are tuned so as to realize the c = 1/2 Ising conformal field
theory, a fact that we establish numerically via Density Matrix Renormalization
Group (DMRG) studies. Time-reversal breaking inter-ladder interactions are
tuned so as to open a bulk gap in the 2D lattice system. This 2D system
supports gapless chiral edge modes with Ising non-Abelian excitations but no
charge excitations, in contrast to the Pfaffian non-Abelian fractional quantum
Hall state.


title:
Improved key rate bounds for practical decoy-state quantum key
  distribution systems

abstract:
  The decoy-state scheme is the most widely implemented quantum key
distribution protocol in practice. In order to account for the finite-size key
effects on the achievable secret key generation rate, a rigorous statistical
fluctuation analysis is required. Originally, a heuristic
Gaussian-approximation technique was used for this purpose, which, despite of
its analytical convenience, was not sufficiently rigorous. The fluctuation
analysis has recently been made rigorous by using the Chernoff bound. There is
a considerable gap, however, between the key rate bounds obtained from these
new techniques and that obtained from the Gaussian assumption. Here, we develop
a tighter bound for the decoy-state method, which yields a smaller failure
probability. This improvement results in a higher key rate and increases the
maximum distance over which secure key exchange is possible. By optimizing the
system parameters, our simulation results show that our new method almost
closes the gap between the two previously proposed techniques and achieves a
similar performance to that of conventional Gaussian approximations.


title:
The Loss Surface of Residual Networks: Ensembles and the Role of Batch
  Normalization

abstract:
  Deep Residual Networks present a premium in performance in comparison to
conventional networks of the same depth and are trainable at extreme depths. It
has recently been shown that Residual Networks behave like ensembles of
relatively shallow networks. We show that these ensembles are dynamic: while
initially the virtual ensemble is mostly at depths lower than half the
network's depth, as training progresses, it becomes deeper and deeper. The main
mechanism that controls the dynamic ensemble behavior is the scaling
introduced, e.g., by the Batch Normalization technique. We explain this
behavior and demonstrate the driving force behind it. As a main tool in our
analysis, we employ generalized spin glass models, which we also use in order
to study the number of critical points in the optimization of Residual
Networks.


title:
A New Yield Simulator for Transiting Planets and False Positives:
  Application to the Next Generation Transit Survey

abstract:
  We present a yield simulator to predict the number and characteristics of
planets, false positives and false alarms in transit surveys. The simulator is
based on a galactic model and the planet occurrence rates measured by the
Kepler mission. It takes into account the observation window function and
measured noise levels of the investigated survey. Additionally, it includes
vetting criteria to identify false positives. We apply this simulator to the
Next Generation Transit Survey (NGTS), a wide-field survey designed to detect
transiting Neptune-sized exoplanets. We find that red noise is the main
limitation of NGTS up to 14th magnitude, and that its obtained level determines
the expected yield. Assuming a red noise level of 1 mmag, the simulation
predicts the following for a four-year survey: 4+-3 Super-Earths, 19+-5 Small
Neptunes, 16+-4 Large Neptunes, 55+-8 Saturn-sized planets and 150+-10
Jupiter-sized planets, along with 4688+-45 eclipsing binaries and 843+-75
background eclipsing binaries. We characterize the properties of these objects
to enhance the early identification of false positives and discuss follow-up
strategies for transiting candidates.


title:
Weak K\"{o}nig's lemma implies the uniform continuity theorem: a direct
  proof

abstract:
  We show in Bishop's constructive mathematics---in particular, using countable
choice---that weak K\"{o}nig's lemma implies the uniform continuity theorem.


title: LTL Model-Checking for Dynamic Pushdown Networks Communicating via Locks

abstract:
  A Dynamic Pushdown Network (DPN) is a set of pushdown systems (PDSs) where
each process can dynamically create new instances of PDSs. DPNs are a natural
model of multi-threaded programs with (possibly recursive) procedure calls and
thread creation. Extending DPNs with locks allows processes to synchronize with
each other. Thus, DPNs with locks are a well adapted formalism to model
multi-threaded programs that synchronize via locks. Therefore, it is important
to have model-checking algorithms for DPNs with locks. We consider in this work
model-checking for DPNs with locks against single-indexed LTL properties of the
form V fi s.t. fi is a LTL formula interpreted over the PDS i. We consider the
model-checking problems w.r.t. simple valuations (i.e, whether a configuration
satisfies an atomic proposition depends only on its control location and held
locks) and w.r.t. regular valuations (i.e., the set of the configurations
satisfying an atomic proposition is a regular set of configurations). We show
that these model-checking problems are decidable.


title: Pattern Formation in Double-Layer Kerr Resonators with Coupled Modes

abstract:
  A double-layer Kerr resonator in which both coupled modes are excited and
interact with each other via incoherent cross-phase modulation is investigated
to reveal stable localized solutions beyond the usual formation mechanism
involving a single mode. Periodic solutions from modulational instability are
found to occur at a slight penalty on the nonlinear efficiency, but they
stabilize the spatial dynamics, leading to dissipative solitons in previously
unattainable regimes. Numerical simulations show paired breather solitons in
addition to temporally stable solutions. The results demonstrate coupled modes
can increase the stability of Kerr frequency comb generation.


title: A Random Dot Product Model for Weighted Networks

abstract:
  This paper presents a generalization of the random dot product model for
networks whose edge weights are drawn from a parametrized probability
distribution. We focus on the case of integer weight edges and show that many
previously studied models can be recovered as special cases of this
generalization. Our model also determines a dimension--reducing embedding
process that gives geometric interpretations of community structure and
centrality. The dimension of the embedding has consequences for the derived
community structure and we exhibit a stress function for determining
appropriate dimensions. We use this approach to analyze a coauthorship network
and voting data from the U.S. Senate.


title: Kakutani's fixed point theorem in constructive mathematics

abstract:
  In this paper we consider Kakutani's extension of the Brouwer fixed point
theorem within the framework of Bishop's constructive mathematics. Kakutani's
fixed point theorem is classically equivalent to Brouwer's fixed point theorem.
The constructive proof of (an approximate) Brouwer's fixed point theorem relies
on a finite combinatorial argument; consequently we must restrict our attention
to uniformly continuous functions. Since Brouwer's fixed point theorem is a
special case of Kakutani's, the mappings in any constructive version of
Kakutani's fixed point theorem must also satisfy some form of uniform
continuity. We discuss the difficulties involved in finding an appropriate
notion of uniform continuity, before giving a constructive version of
Kakutani's fixed point theorem which is classically equivalent to the standard
formulation. We also consider the reverse constructive mathematics of
Kakutani's fixed point theorem, and provide a constructive proof of Kakutani's
first application of his theorem---a generalisation of von Neumann's minimax
theorem.


title:
Color reconnection and event-by-event fluctuations of mean transverse
  momentum in proton-proton collisions at sqrt_s = 7 TeV in PYTHIA6.4

abstract:
  Based on PYTHIA6.428, event-by-event fluctuations of the mean transverse
momentum in proton- proton collisions at sqrt_s = 7 TeV are studied using
several measures of the fluctuations. The study compares results of the
fluctuations for events where color reconnection is turned on, with those where
color reconnection is turned off. The comparison reveals that some of the
fluctuation measures are much more sensitive to color reconnection than others.
Through the comparison it is demonstrated for the first time that for
proton-proton collisions at the Large Hadron Collider, these sensitive measures
of the mean transverse momentum fluctuations can serve as alternative probes to
color reconnection and color reconnection is a non-trivial source of the
event-by-event fluctuations.


title: Field-strength correlators for QCD in a magnetic background

abstract:
  We present the results of an exploratory study (by means of Monte Carlo
simulations on the lattice) of the properties of the gauge-invariant two-point
correlation functions of the gauge-field strengths for $N_f=2$ QCD at zero
temperature and in the presence of a magnetic background field: the analysis
provides evidence for the emergence of anisotropies in the nonperturbative part
of the correlators and for an increase of the gluon condensate as a function of
the external magnetic field.


title: On the construction of general equilibria in a competitive economy

abstract:
  This paper gives a constructive treatment of McKenzie's theorem on the
existence of general equilibria. While the full theorem does not admit a
constructive proof, and hence does not admit a computational realisation, we
show that if we strengthen the conditions on our preference relation---we
require $\succ$ to be uniformly rotund in the sense of Bridges [5]---then we
can find `approximate equilibrium points,' points at which the collective
profit may not be maximal, but can be made arbitrarily close to being maximal.


title: Geometry of Adaptive Martensite in Ni-Mn-based Heusler alloys

abstract:
  Modulated martensites play an important role in magnetic shape memory alloys,
because all functional properties are closely connected to the twin
microstructure and the phase boundary. The nature of the modulated martensites
is still unclear. One approach is the concept of adaptive martensite, which
regards all modulated phases as nanotwinned microstructures. In this article,
we use the Ni-Mn-based shape memory alloys as an example to show the geometric
rationale behind this concept using analytic equations based on the
phenomenological theory of martensite. This could enhance discussions about the
implications of the adaptive martensite by showing the exact relations between
the various unit cells used to describe the structure. We use the concept to
discuss the compatibility at the habit plane, the nature of high-order twin
boundaries and the dependence of the lattice constants on the different types
of modulation.


title:
Single crystal growth, structure and magnetic properties of Pr2Hf2O7
  pyrochlore

abstract:
  Large single crystals of the pyrochlore Pr2Hf2O7 have been successfully grown
by the floating zone technique using an optical furnace equipped with high
power Xenon arc lamps. Structural investigations have been carried out by both
synchrotron X-ray and neutron powder diffraction to establish the
crystallographic structure of the materials produced. The magnetic properties
of the single crystals have been determined for magnetic fields applied along
different crystallographic axes. The results reveal that Pr2Hf2O7 is an
interesting material for further investigations as a frustrated magnet. The
high quality of the crystals produced make them ideal for detailed
investigations, especially those using neutron scattering techniques.


title: Network-wide Configuration Synthesis

abstract:
  Computer networks are hard to manage. Given a set of high-level requirements
(e.g., reachability, security), operators have to manually figure out the
individual configuration of potentially hundreds of devices running complex
distributed protocols so that they, collectively, compute a compatible
forwarding state. Not surprisingly, operators often make mistakes which lead to
downtimes. To address this problem, we present a novel synthesis approach that
automatically computes correct network configurations that comply with the
operator's requirements. We capture the behavior of existing routers along with
the distributed protocols they run in stratified Datalog. Our key insight is to
reduce the problem of finding correct input configurations to the task of
synthesizing inputs for a stratified Datalog program. To solve this synthesis
task, we introduce a new algorithm that synthesizes inputs for stratified
Datalog programs. This algorithm is applicable beyond the domain of networks.
We leverage our synthesis algorithm to construct the first network-wide
configuration synthesis system, called SyNET, that support multiple interacting
routing protocols (OSPF and BGP) and static routes. We show that our system is
practical and can infer correct input configurations, in a reasonable amount
time, for networks of realistic size (> 50 routers) that forward packets for
multiple traffic classes.


title:
Inferring disease causing genes and their pathways: A mathematical
  perspective

abstract:
  A system level view of cellular processes for human and several organisms can
be cap- tured by analyzing molecular interaction networks. A molecular
interaction network formed of differentially expressed genes and their
interactions helps to understand key players behind disease development. So, if
the functions of these genes are blocked by altering their interactions, it
would have a great impact in controlling the disease. Due to this promising
consequence, the problem of inferring disease causing genes and their pathways
has attained a crucial position in computational biology research. However,
considering the huge size of interaction networks, executing computations can
be costly. Review of literatures shows that the methods proposed for finding
the set of disease causing genes could be assessed in terms of their accuracy
which a perfect algorithm would find. Along with accuracy, the time complexity
of the method is also important, as high time complexities would limit the
number of pathways that could be found within a pragmatic time interval.


title:
Confinement, Holonomy and Correlated Instanton-Dyon Ensemble I: SU(2)
  Yang-Mills Theory

abstract:
  The mechanism of confinement in Yang-Mills theories remains a challenge to
our understanding of nonperturbative gauge dynamics. While it is widely
perceived that confinement may arise from chromo-magnetically charged gauge
configurations with nontrivial topology, it is not clear what types of
configurations could do that and how, in pure Yang-Mills and QCD-like
(non-supersymmetric) theories. Recently a promising approach has emerged, based
on statistical ensembles of dyons/anti-dyons that are constituents of
instanton/anti-instanton solutions with nontrivial holonomy where the holonomy
plays a vital role as an effective "Higgsing" mechanism. We report a thorough
numerical investigation of the confinement dynamics in SU(2) Yang-Mills theory
by constructing such a statistical ensemble of correlated instanton-dyons.


title:
Robust Phase Retrieval Algorithm for Time-Frequency Structured
  Measurements

abstract:
  We address the problem of signal reconstruction from intensity measurements
with respect to a measurement frame. This non-convex inverse problem is known
as phase retrieval. The case considered in this paper concerns phaseless
measurements taken with respect to a Gabor frame. It arises naturally in many
practical applications, such as diffraction imaging and speech recognition. We
present a reconstruction algorithm that uses a nearly optimal number of
phaseless time-frequency structured measurements and discuss its robustness in
the case when the measurements are corrupted by noise. We show how geometric
properties of the measurement frame are related to the robustness of the
phaseless reconstruction. The presented algorithm is based on the idea of
polarization as proposed by Alexeev, Bandeira, Fickus, and Mixon.


title: Arc diagrams, flip distances, and Hamiltonian triangulations

abstract:
  We show that every triangulation (maximal planar graph) on $n\ge 6$ vertices
can be flipped into a Hamiltonian triangulation using a sequence of less than
$n/2$ combinatorial edge flips. The previously best upper bound uses
$4$-connectivity as a means to establish Hamiltonicity. But in general about
$3n/5$ flips are necessary to reach a $4$-connected triangulation. Our result
improves the upper bound on the diameter of the flip graph of combinatorial
triangulations on $n$ vertices from $5.2n-33.6$ to $5n-23$. We also show that
for every triangulation on $n$ vertices there is a simultaneous flip of less
than $2n/3$ edges to a $4$-connected triangulation. The bound on the number of
edges is tight, up to an additive constant. As another application we show that
every planar graph on $n$ vertices admits an arc diagram with less than $n/2$
biarcs, that is, after subdividing less than $n/2$ (of potentially $3n-6$)
edges the resulting graph admits a $2$-page book embedding.


title:
Constructing the demand function of a strictly convex preference
  relation

abstract:
  We give conditions under which the demand function of a strictly convex
preference relation can be constructed.


title: Equivalents of disjunctive Markov's principle

abstract:
  The purpose of this short note is to point out a rich source of natural
equivalents of the weak semi-intuitionistic principle MP$^\vee$ in reverse
constructive mathematics: many simple theorems from Euclidean geometry when
read classically (for example with $<$ interpreted as $\leqslant$ and $\neq$)
are equivalent to disjunctive Markov's principle MP$^\vee$. We give an example
of this phenomenon.


title: Polaron model of pseudogap state in quasi-one-dimentional systems

abstract:
  A brief overview of the basic concepts and problems of the physics of
quasi-one-dimensional compounds is done. Consistent theoretical description of
the so-called pseudogap state remains the main problem. A simplified model of
the pseudogap state, based on the picture of small polarons formation in the
framework of cluster perturbation theory is considered.


title: Decompositions of Grothendieck Polynomials

abstract:
  We investigate the longstanding problem of finding a combinatorial rule for
the Schubert structure constants in the $K$-theory of flag varieties (in type
$A$). The Grothendieck polynomials of A. Lascoux-M.-P. Sch\"{u}tzenberger
(1982) serve as polynomial representatives for $K$-theoretic Schubert classes;
however no positive rule for their multiplication is known outside the
Grassmannian case. We contribute a new basis for polynomials, give a positive
combinatorial formula for the expansion of Grothendieck polynomials in these
glide polynomials, and provide a positive combinatorial Littlewood-Richardson
rule for expanding a product of Grothendieck polynomials in the glide basis.
Our techniques easily extend to the $\beta$-Grothendieck polynomials of S.
Fomin-A. Kirillov (1994), representing classes in connective $K$-theory, and we
state our results in this more general context.
  A specialization of the glide basis recovers the fundamental slide
polynomials of S. Assaf-D. Searles (2016), which play an analogous role with
respect to the Chow ring of flag varieties. Additionally, the stable limits of
another specialization of glide polynomials are T. Lam-P. Pylyavskyy's (2007)
basis of multi-fundamental quasisymmetric functions, $K$-theoretic analogues of
I. Gessel's (1984) fundamental quasisymmetric functions. Those glide
polynomials that are themselves quasisymmetric are truncations of
multi-fundamental quasisymmetric functions and form a basis of quasisymmetric
polynomials.


title:
UniFlex: Accelerating Networking Research and Experimentation through
  Software-Defined Wireless Networking

abstract:
  Classical control and management plane for computer networks is addressing
individual parameters of protocol layers within an individual wireless network
device. We argue that this is not sufficient in phase of increasing deployment
of highly re-configurable systems, as well as heterogeneous wireless systems
co-existing in the same radio spectrum which demand harmonized, frequently even
coordinated adaptation of multiple parameters in different protocol layers
(cross-layer) in multiple network devices (cross-node).
  We propose UniFlex, a framework enabling unified and flexible radio and
network control. It provides an API enabling coordinated cross-layer control
and management operation over multiple network nodes. The controller logic may
be implemented either in a centralized or distributed manner. This allows to
place time-sensitive control functions close to the controlled device (i.e.,
local control application), off-load more resource hungry network application
to compute servers and make them work together to control entire network.
  The UniFlex framework was prototypically implemented and provided to the
research community as open-source. We evaluated the the framework in a number
of use-cases, what proved its usability.


title:
Optimal Extraction and Taxation of Strategic Natural Resources: A
  Differential Game Approach

abstract:
  This paper studies the optimal extraction and taxation of nonrenewable
natural resources. It is well known that the market values of the main
strategic resources such as oil, natural gas, uranium, copper,..., etc,
fluctuate randomly following global and seasonal macroeconomic parameters,
these values are modeled using Markov switching L\'evy processes. We formulate
this problem as a differential game. The two players of this differential game
are the mining company whose aim is to maximize the revenues generated from its
extracting activities and the government agency in charge of regulating and
taxing natural resources. We prove the existence of a Nash equilibrium. The
corresponding Hamilton Jacobi Isaacs equations are completely solved and the
value functions as well as the optimal extraction and taxation rates are
derived in closed-form. A Numerical example is presented to illustrate our
findings.


title: Superconductivity Induced by High Pressure in Weyl Semimetal TaP

abstract:
  Weyl semimetal defines a material with three dimensional Dirac cones which
appear in pair due to the breaking of spatial inversion or time reversal
symmetry. Superconductivity is the state of quantum condensation of paired
electrons. Turning a Weyl semimetal into superconducting state is very
important in having some unprecedented discoveries. In this work, by doing
resistive measurements on a recently recognized Weyl semimetal TaP under
pressure up to about 100 GPa, we observe superconductivity at about 70 GPa. The
superconductivity retains when the pressure is released. The systematic
evolutions of resistivity and magnetoresistance with pressure are well
interpreted by the relative shift between the chemical potential and paired
Weyl points. Calculations based on the density functional theory also
illustrate the structure transition at about 70GPa, the phase at higher
pressure may host superconductivity. Our discovery of superconductivity in TaP
by pressure will stimulate further study on superconductivity in Weyl
semimetals.


title: Emerging interdependence between stock values during financial crashes

abstract:
  To identify emerging interdependencies between traded stocks we investigate
the behavior of the stocks of FTSE 100 companies in the period 2000-2015, by
looking at daily stock values. Exploiting the power of information theoretical
measures to extract direct influences between multiple time series, we compute
the information flow across stock values to identify several different regimes.
While small information flows is detected in most of the period, a dramatically
different situation occurs in the proximity of global financial crises, where
stock values exhibit strong and substantial interdependence for a prolonged
period. This behavior is consistent with what one would generally expect from a
complex system near criticality in physical systems, showing the long lasting
effects of crashes on stock markets.


title:
Discriminative Acoustic Word Embeddings: Recurrent Neural Network-Based
  Approaches

abstract:
  Acoustic word embeddings --- fixed-dimensional vector representations of
variable-length spoken word segments --- have begun to be considered for tasks
such as speech recognition and query-by-example search. Such embeddings can be
learned discriminatively so that they are similar for speech segments
corresponding to the same word, while being dissimilar for segments
corresponding to different words. Recent work has found that acoustic word
embeddings can outperform dynamic time warping on query-by-example search and
related word discrimination tasks. However, the space of embedding models and
training approaches is still relatively unexplored. In this paper we present
new discriminative embedding models based on recurrent neural networks (RNNs).
We consider training losses that have been successful in prior work, in
particular a cross entropy loss for word classification and a contrastive loss
that explicitly aims to separate same-word and different-word pairs in a
"Siamese network" training setting. We find that both classifier-based and
Siamese RNN embeddings improve over previously reported results on a word
discrimination task, with Siamese RNNs outperforming classification models. In
addition, we present analyses of the learned embeddings and the effects of
variables such as dimensionality and network structure.


title: Cohomology of partial smash products

abstract:
  We define the partial group cohomology as the right derived functor of the
functor of partial invariants, we relate this cohomology with partial
derivations and with the partial augmentation ideal and we show that there
exists a Grothendieck spectral sequence relating cohomology of partial smash
algebras with partial group cohomology and algebra cohomology.


title:
On the Uplink Spectral Efficiency of Full-Duplex Cooperative OFDMA
  Systems

abstract:
  In this paper, we develop a resource allocation algorithm for uplink of
in-band full-duplex (FD) cellular networks. The FD cellular network is assumed
to be based on orthogonal frequency division multiple access (OFDMA) and
consists of a base station communicating with multiple users. Some of the users
in the network act as relay for other users and help them to transmit their
data to the base station. These relays are FD and work based on amplify and
forward (AF) protocol. By appropriate selection of the relays and optimized
allocation of subcarriers and powers to all users, we try to maximize the total
sum rate of the network. During this optimization, we also impose some
constraints on the users' quality of service (QoS) and power. We propose a new
algorithm to select the best relays based on the users' maximum data rate and
also use Linear Assignment Problem Jonker-Volgenant (LAPJV) algorithm for
subcarrier assignment. It is proved that the resulting optimization problem can
be converted to a convex problem, and hence it can be solved by standard
numerical methods. The simulation results demonstrate the effect of the
proposed scheme on the sum rate and coverage of the network.


title: Weak {$q$}-concavity conditions for {$CR$}-manifolds

abstract:
  We introduce various notions of q-pseudo-concavity for abstract CR manifolds
and we apply these notions to the study of hyoo-ellipticity, maximum modulus
principle and Cauchy problems for CR functions.


title: The Neural Noisy Channel

abstract:
  We formulate sequence to sequence transduction as a noisy channel decoding
problem and use recurrent neural networks to parameterise the source and
channel models. Unlike direct models which can suffer from explaining-away
effects during training, noisy channel models must produce outputs that explain
their inputs, and their component models can be trained with not only paired
training samples but also unpaired samples from the marginal output
distribution. Using a latent variable to control how much of the conditioning
sequence the channel model needs to read in order to generate a subsequent
symbol, we obtain a tractable and effective beam search decoder. Experimental
results on abstractive sentence summarisation, morphological inflection, and
machine translation show that noisy channel models outperform direct models,
and that they significantly benefit from increased amounts of unpaired output
data that direct models cannot easily use.


title: Results of dark matter searches with the ANTARES neutrino telescope

abstract:
  Neutrino telescopes have a wide scientic scope. One of their main goals is
the detection of dark matter, for which they have specic advantages. Neutrino
telescopes offer the possibility of looking at several kinds of sources, not
all of them available to other indirect searches. In this work we provide an
overview of the results obtained by the ANTARES neutrino telescope, which has
been taking data for almost ten years. One of the most interesting ones is the
Sun, since a detection of high energy neutrinos from it would be a very clean
indication of dark matter, given that no signicant astrophysical backgrounds
are expected, contrary to other indirect searches. Moreover, the limits from
neutrino telescopes for spin-dependent cross section are the most restrictive
ones. Another interesting source is the Galactic Centre, for which ANTARES has
a better visibility than IceCube, due to its geographical location. This search
gives limits on the annihilation cross section. Other dark matter searches
carried out in ANTARES include the Earth and dwarf galaxies.


title: Application of the Generalized Linear Models in Actuarial Framework

abstract:
  This paper aims to review the methodology behind the generalized linear
models which are used in analyzing the actuarial situations instead of the
ordinary multiple linear regression. We introduce how to assess the adequacy of
the model which includes comparing nested models using the deviance and the
scaled deviance. The Akiake information criterion is proposed as a
comprehensive tool for selecting the adequate model. We model a simple
automobile portfolio using the generalized linear models, and use the best
chosen model to predict the number of claims made by the policyholders in the
portfolio.


title: Charmonium physics with heavy ions: experimental results

abstract:
  Thirty years ago, the suppression of charmonium production in heavy-ion
collisions was first proposed as an unambiguous signature for the formation of
a Quark-Gluon Plasma. Since then, experiments at fixed-target accelerators
(SPS) and hadronic colliders (RHIC, LHC) have investigated this observable and
discovered a wide range of effects, that have been related to the original
proposal but at the same time have also prompted a strong development in the
underlying theory concepts. In this contribution, I will review the main
achievements of this field, with emphasis on recent results obtained by LHC
experiments.


title: Nodal Finite Element de Rham Complexes

abstract:
  We construct 2D and 3D finite element de Rham sequences of arbitrary
polynomial degrees with extra smoothness. Some of these elements have nodal
degrees of freedom (DoFs) and can be considered as generalisations of scalar
Hermite and Lagrange elements. Using the nodal values, the number of global
degrees of freedom is reduced compared with the classical N\'{e}d\'{e}lec and
Brezzi-Douglas-Marini (BDM) finite elements, and the basis functions are more
canonical and easier to construct. Our finite elements for ${H}(\mathrm{div})$
with regularity $r=2$ coincide with the nonstandard elements given by Stenberg
(Numer Math 115(1): 131-139, 2010). We show how regularity decreases in the
finite element complexes, so that they branch into known complexes. The
standard de Rham complexes of Whitney forms and their higher order version can
be regarded as the family with the lowest regularity. The construction of the
new families is motivated by the finite element systems.%, and we also
establish local exact sequences (geometric decomposition) for the new elements.


title: The Binary Central Star of Hf 38

abstract:
  Despite years of effort, the impact of central star binarity on planetary
nebula formation and shaping remains unclear. This is hampered by the fact that
detecting central star binarity is inherently difficult, and requires very
precise observations. The fraction of planetary nebulae with binary central
stars therefore remains elusive. This work presents initial results of central
star analysis using data from the VST H$\alpha$ Survey of the Southern Galactic
Plane and Bulge (VPHAS+). The true central star of PN Hf 38 has been revealed,
and it exhibits a 0.465$\pm$0.334 $i$ band magnitude excess, indicative of a
M0V companion.


title: B\^ocher and Abstract Contractions of 2nd Order Quadratic Algebras

abstract:
  Quadratic algebras are generalizations of Lie algebras which include the
symmetry algebras of 2nd order superintegrable systems in 2 dimensions as
special cases. The superintegrable systems are exactly solvable physical
systems in classical and quantum mechanics. Distinct superintegrable systems
and their quadratic algebras can be related by geometric contractions, induced
by B\^ocher contractions of the conformal Lie algebra
${\mathfrak{so}}(4,\mathbb {C})$ to itself. In this paper we give a precise
definition of B\^ocher contractions and show how they can be classified. They
subsume well known contractions of ${\mathfrak{e}}(2,\mathbb {C})$ and
${\mathfrak{so}}(3,\mathbb {C})$ and have important physical and geometric
meanings, such as the derivation of the Askey scheme for obtaining all
hypergeometric orthogonal polynomials as limits of Racah/Wilson polynomials. We
also classify abstract nondegenerate quadratic algebras in terms of an
invariant that we call a canonical form. We describe an algorithm for finding
the canonical form of such algebras. We calculate explicitly all canonical
forms arising from quadratic algebras of 2D nondegenerate superintegrable
systems on constant curvature spaces and Darboux spaces. We further discuss
contraction of quadratic algebras, focusing on those coming from
superintegrable systems.


title: SU(2)$_{\tiny\mbox{CMB}}$ at high redshifts and the value of $H_0$

abstract:
  We investigate a high-$z$ cosmological model to compute the co-moving sound
horizon $r_s$ at baryon-velocity freeze-out towards the end of hydrogen
recombination. This model assumes a replacement of the conventional CMB photon
gas by deconfining SU(2) Yang-Mills thermodynamics, three flavours of massless
neutrinos ($N_\nu=3$), and a {\sl purely baryonic} matter sector (no cold
dark-matter (CDM)). The according SU(2) temperature-redshift relation of the
CMB is contrasted with recent measurements appealing to the thermal
Sunyaev-Zel'dovich effect and CMB-photon absorption by molecular rotations
bands or atomic hyperfine levels. Relying on a realistic simulation of the
ionization history throughout recombination, we obtain $z_*=1693.55\pm 6.98$
and $z_{\rm drag}=1812.66\pm 7.01$. Due to considerable widths of the
visibility functions in the solutions to the associated Boltzmann hierarchy and
Euler equation we conclude that $z_*$ and $z_{\rm drag}$ over-estimate the
redshifts for the respective photon and baryon-velocity freeze-out. Realistic
decoupling values turn out to be $z_{{\rm lf},*}=1554.89\pm 5.18$ and $z_{\rm
lf,drag}=1659.30\pm 5.48$. With $r_s(z_{\rm lf,drag})=(137.19\pm 0.45)\,$Mpc
and the essentially model independent extraction of $r_s\cdot H_0=\mbox{const}$
from low-$z$ data in arXiv:1607.05617 we obtain a good match with the value
$H_0=(73.24\pm 1.74)\,$km\,s$^{-1}$\,Mpc$^{-1}$ extracted in arXiv:1604.01424
by appealing to Cepheid calibrated SNe~Ia, new parallax measurements, stronger
constraints on the Hubble flow, and a refined computation of distance to
NGC4258 from maser data. We briefly comment on a possible interpolation of our
high-$z$ model, invoking percolated and unpercolated U(1) topological solitons
of a Planck-scale axion field, to the phenomenologically successful low-$z$
$\Lambda$CDM cosmology.


title:
The challenging task of determining star formation rates: the case of a
  massive stellar burst in the brightest cluster galaxy of Phoenix galaxy
  cluster

abstract:
  Star formation in galaxies at the center of cooling-flow galaxy clusters is
an important phenomenon in the context of formation and evolution of massive
galaxies in the Universe. Yet, star formation rates (SFRs) in such systems
continue to be elusive. We use our Bayesian-motivated spectral energy
distribution (SED)-fitting code, BAYESCOOL, to estimate the plausible SFR
values in the brightest cluster galaxy of a massive, X-ray luminous galaxy
cluster, Phoenix. Previous studies of Phoenix have resulted in the highest
measurement of SFR for any galaxy, with the estimates reaching up to 1000 solar
masses/yr. However, a very small number of models have been considered in those
studies. BAYESCOOL allows us to probe a large parameter space. We consider two
models for star formation history, instantaneous bursts and continuous star
formation, a wide range of ages for the old and the young stellar population,
along with other discrete parameters, such as the initial mass function,
metallicities, internal extinction and extinction law. We find that in the
absence of any prior except that the maximum cooling rate < 3000 solar
masses/yr, the SFR lies in the range (2230-2890) solar masses/yr. If we impose
an observational prior on the internal extinction, E(B-V) < 0.6, the best-fit
SFR lies in (454-494) solar masses/yr, and we consider this as the most
probable range of SFR values for Phoenix. The SFR dependence on the extinction
is a reflection of the standard age-extinction degeneracy, which can be
overcome by using a prior on one of the two quantities in question.


title: Knotted fields and explicit fibrations for lemniscate knots

abstract:
  We give an explicit construction of complex maps whose nodal line have the
form of lemniscate knots. We review the properties of lemniscate knots, defined
as closures of braids where all strands follow the same transverse (1, $\ell$)
Lissajous figure, and are therefore a subfamily of spiral knots generalising
the torus knots. We then prove that such maps exist and are in fact fibrations
with appropriate choices of parameters. We describe how this may be useful in
physics for creating knotted fields, in quantum mechanics, optics and
generalising to rational maps with application to the Skyrme-Faddeev model. We
also prove how this construction extends to maps with weakly isolated
singularities.


title: Generalizing the Lorentz transformations

abstract:
  In this paper we develop a framework allowing a natural extension of the
Lorentz transformations. To begin, we show that by expanding conventional
four-dimensional spacetime to eight-dimensions that a natural generalization is
indeed obtained. We then find with these generalized coordinate transformations
acting on Maxwell's equations that the electromagnetic field transformations
are nevertheless unchanged. We find further, that if we assume the absence of
magnetic monopoles, in accordance with Maxwell's theory, our generalized
transformations are then restricted to be the conventional ones. While the
conventional Lorentz transformations are indeed recovered from our framework,
we nevertheless provide a new perspective into why the Lorentz transformations
are constrained to be the conventional ones. Also, this generalized framework
may assist in explaining several unresolved questions in electromagnetism as
well as to be able to describe quasi magnetic monopoles found in spin-ice
systems.


title: Application of SIR epidemiological model: new trends

abstract:
  The simplest epidemiologic model composed by mutually exclusive compartments
SIR (susceptible-infected-susceptible) is presented to describe a reality. From
health concerns to situations related with marketing, informatics or even
sociology, several are the fields that are using this epidemiological model as
a first approach to better understand a situation. In this paper, the basic
transmission model is analyzed, as well as simple tools that allows us to
extract a great deal of information about possible solutions. A set of
applications - traditional and new ones - is described to show the importance
of this model.


title:
The Second Law of Thermodynamics and Entropy-Decreasing Processes With
  $^4$He Superflows

abstract:
  We review on a recently proposed quantum exception to the second law of
thermodynamics. We emphasize that $^4$He superflows, like any other forms of
flows, shall carry entropy or heat in a thermal environment. Following that,
one can use a heterogeneous $^4$He superflow loop to realize entropy-decreasing
processes. We also mention that the heat content of a superflow has an unusual
dependence on flow velocity, which is an important factor contributing to the
entropy-decreasing processes.


title:
Strong Magnetic field effects on Neutron Stars within $f(T)$ theory of
  gravity

abstract:
  We investigate in this paper the structures of neutron stars under the strong
magnetic field in the framework of $f(T)$ gravity where $T$ denotes the scalar
torsion. The TOV equations in this theory of gravity have been considered and
numerical resolution of these equations has been performed within perturbative
approach taking into account the equation of state of neutron dense matter in
magnetic field. We simplify the problem by considering the very strong magnetic
field which affects considerably the dense matter; and for quadratic and cubic
corrections to Teleparallel term, one finds that the mass of neutron stars can
increase for different values of the perturbation parameter. The deviation from
Teleparallel for different values of magnetic field is found out and this
feature is very appreciable in the case of cubic correction. Our results are
related to the hadronic particles description with very small hyperon
contributions and the mass-radius evolution is consistency with the
observational data.


title:
PixelSNE: Visualizing Fast with Just Enough Precision via Pixel-Aligned
  Stochastic Neighbor Embedding

abstract:
  Embedding and visualizing large-scale high-dimensional data in a
two-dimensional space is an important problem since such visualization can
reveal deep insights out of complex data. Most of the existing embedding
approaches, however, run on an excessively high precision, ignoring the fact
that at the end, embedding outputs are converted into coarse-grained discrete
pixel coordinates in a screen space. Motivated by such an observation and
directly considering pixel coordinates in an embedding optimization process, we
accelerate Barnes-Hut tree-based t-distributed stochastic neighbor embedding
(BH-SNE), known as a state-of-the-art 2D embedding method, and propose a novel
method called PixelSNE, a highly-efficient, screen resolution-driven 2D
embedding method with a linear computational complexity in terms of the number
of data items. Our experimental results show the significantly fast running
time of PixelSNE by a large margin against BH-SNE, while maintaining the
minimal degradation in the embedding quality. Finally, the source code of our
method is publicly available at https://github.com/awesome-davian/PixelSNE


title:
Sparse multivariate factorization by mean of a few bivariate
  factorizations

abstract:
  We describe an algorithm to factor sparse multivariate polynomials using O(d)
bivariate factorizations where d is the number of variables. This algorithm is
implemented in the Giac/Xcas computer algebra system.


title: Heat Flows on Time-dependent Metric Measure Spaces and Super-Ricci Flows

abstract:
  We study the heat equation on time-dependent metric measure spaces (as well
as the dual and the adjoint heat equation) and prove existence, uniqueness and
regularity. Of particular interest are properties which characterize the
underlying space as a super Ricci flow as previously introduced by the second
author. Our main result yields the equivalence of (i) dynamic convexity of the
Boltzmann entropy on the (time-dependent) $L^2$-Wasserstein space; (ii)
monotonicity of $L^2$-Kantorovich-Wasserstein distances under the dual heat
flow acting on probability measures (backward in time); (iii) gradient
estimates for the heat flow acting on functions (forward in time); (iv) a
Bochner inequality involving the time-derivative of the metric.
  Moreover, we characterize the heat flow on functions as the unique forward
EVI-flow for the (time-dependent) energy in $L^2$-Hilbert space and the dual
heat flow on probability measures as the unique backward EVI-flow for the
(time-dependent) Boltzmann entropy in $L^2$-Wasserstein space.


title: Robust change-point detection in panel data

abstract:
  In panel data we observe a usually high number N of individuals over a time
period T. Even if T is large one often assumes stability of the model over
time. We propose a nonparametric and robust test for a change in location and
derive its asymptotic distribution under short range dependence and for N, T
tending to infinity. Some simulations show its usefulness under heavy tailed
distributions.


title:
Geophysical flows under location uncertainty, Part I Random transport
  and general models

abstract:
  A stochastic flow representation is considered with the Eulerian velocity
decomposed between a smooth large scale component and a rough small-scale
turbulent component. The latter is specified as a random field uncorrelated in
time. Subsequently, the material derivative is modified and leads to a
stochastic version of the material derivative to include a drift correction ,
an inhomogeneous and anisotropic diffusion, and a multiplicative noise. As
derived, this stochastic transport exhibits a remarkable energy conservation
property for any realizations. As demonstrated, this pivotal operator further
provides elegant means to derive stochastic formulations of classical
representations of geophysical flow dynamics.


title: ER= EPR and Non-Perturbative Action Integrals for Quantum Gravity

abstract:
  In this paper, we construct and calculate a non-perturbative path integrals
in a multiply-connected space-time. This is done by by summing over homotopy
classes of paths. The topology of the space-time is defined by Einstein-Rosen
bridges (ERB) forming from the entanglement of quantum foam described by
virtual black holes. As these `bubbles' are entangled, they ar econnected by
Plankian ERB's because of the $ER=EPR$ conjecture. Hence the space-time will
possess a large first Betti number $B1$. For any compact 2-surface in the
space-time, the topology (in particular the homotopy) of that surface is
not-trivial, due to the large number of Plankian ERB's that define homotopy
though this surface. The quantisation of space-time with this topology - along
with the proper choice of the 2-surfaces - is conjectured to allow
anon-perturbative path integrals of quantum gravity theory over the space-time
manifold.


title: The local Tully-Fisher relation for dwarf galaxies

abstract:
  We study different incarnations of the Tully-Fisher (TF) relation for the
Local Volume (LV) galaxies taken from Updated Nearby Galaxy Catalog. The UNGC
sample contains 656 galaxies with $W_{50}$ HI-line-width estimates, mostly
belonging to low mass dwarfs. Of them, 296 objects have distances measured with
accuracy better than 10%. For the sample of 331 LV galaxies having baryonic
masses $\log M_{bar} > 5.8 \log M_\odot$ we obtain a relation $\log M_{bar}=
2.49 \log W_{50} + 3.97$ with observed scatter of 0.38 dex. The largest factors
affecting the scatter are observational errors in $K$-band magnitudes and
$W_{50}$ line widths for the tiny dwarfs, as well as uncertainty of their
inclinations. We find that accounting for the surface brightness of the LV
galaxies, or their gas fraction, or specific star formation rate, or the
isolation index do not reduce essentially the observed scatter on the baryonic
TF-diagram. We also notice that a sample of 71 dSph satellites of the Milky Way
and M31 with known stellar velocity dispersion $\sigma^*$ tends to follow
nearly the same bTF relation, having slightly lower masses than that of
late-type dwarfs.


title:
Cosmic phylogeny: reconstructing the chemical history of the solar
  neighbourhood with an evolutionary tree

abstract:
  Using 17 chemical elements as a proxy for stellar DNA, we present a full
phylogenetic study of stars in the solar neighbourhood. This entails applying a
clustering technique that is widely used in molecular biology to construct an
evolutionary tree from which three branches emerge. These are interpreted as
stellar populations which separate in age and kinematics and can be thus
attributed to the thin disk, the thick disk, and an intermediate population of
probable distinct origin. We further find six lone stars of intermediate age
that could not be assigned to any population with enough statistical
significance. Combining the ages of the stars with their position on the tree,
we are able to quantify the mean rate of chemical enrichment of each of the
populations, and thus show in a purely empirical way that the star formation
rate in the thick disk is much higher than in the thin disk. We are also able
to estimate the relative contribution of dynamical processes such as radial
migration and disk heating to the distribution of chemical elements in the
solar neighbourhood. Our method offers an alternative approach to chemical
tagging methods with the advantage of visualising the behaviour of chemical
elements in evolutionary trees. This offers a new way to search for `common
ancestors' that can reveal the origin of solar neighbourhood stars.


title: Anomalous Effects from Dipole-Environment Quantum Entanglement

abstract:
  In this work, we analyze anomalous effects observed in the operation of two
different technological devices: a magnetic core and a parallel plate
(symmetrical or asymmetrical) capacitor. From experimental measurements on both
devices, we detected small raised anomalous forces that cannot be explained by
known interactions in the traditional theories. As the variations of device
inertia have not been completely understood by means of current theories, we
here propose a theoretical framework in which the anomalous effects can
consistently be explained by a preexisting state of quantum entanglement
between the external environment and either magnetic dipoles of magnetic cores
or electric dipoles of capacitors, so that the effects would be manifested by
the application of a strong magnetic field on the former or an intense electric
field on the latter. The values of the macroscopic observables calculated in
such a theoretical framework revealed good agreement with the experimental
measurements performed in both cases, so that the non - locality hypothesis
based on the generalized quantum correlation between dipoles and environment is
consistent as explanation for the anomalous effects observed. The control and
enhancement of the effect can allow the future viability of a new technology
based on electric propulsion of rockets and aircrafts.


title: Statistical simulations of the dust foreground to CMB polarization

abstract:
  The characterization of the dust polarization foreground to the Cosmic
Microwave Background (CMB) is a necessary step towards the detection of the
B-mode signal associated with primordial gravitational waves. We present a
method to simulate maps of polarized dust emission on the sphere, similarly to
what is done for the CMB anisotropies. This method builds on the understanding
of Galactic polarization stemming from the analysis of Planck data. It relates
the dust polarization sky to the structure of the Galactic magnetic field and
its coupling with interstellar matter and turbulence. The Galactic magnetic
field is modelled as a superposition of a mean uniform field and a random
component with a power-law power spectrum of exponent $\alpha_{\rm M}$. The
model parameters are constrained to fit the power spectra of dust polarization
EE, BB and TE measured using Planck data. We find that the slopes of the E and
B power spectra of dust polarization are matched for $\alpha_{\rm M} = -2.5$.
The model allows us to compute multiple realizations of the Stokes Q and U maps
for different realizations of the random component of the magnetic field, and
to quantify the variance of dust polarization spectra for any given sky area
outside of the Galactic plane. The simulations reproduce the scaling relation
between the dust polarization power and the mean total dust intensity including
the observed dispersion around the mean relation. We also propose a method to
carry out multi-frequency simulations including the decorrelation measured
recently by Planck, using a given covariance matrix of the polarization maps.
These simulations are well suited to optimize component separation methods and
to quantify the confidence with which the dust and CMB B-modes can be separated
in present and future experiments. We also provide an astrophysical perspective
on our modeling of the dust polarization spectra.


title:
Spectral-Timing Analysis of the Lower kHz QPO in the Low-Mass X-ray
  Binary Aquila X-1

abstract:
  Spectral-timing products of kilohertz quasi-periodic oscillations (kHz QPOs)
in low-mass X-ray binary (LMXB) systems, including energy- and
frequency-dependent lags, have been analyzed previously in 4U 1608-52, 4U
1636-53, and 4U 1728-34. Here, we study the spectral-timing properties of the
lower kHz QPO of the neutron star LMXB Aquila X-1 for the first time. We
compute broadband energy lags, as well as energy-dependent lags and the
covariance spectrum using data from the Rossi X-ray Timing Explorer (RXTE). We
find very similar characteristics to other previously studied systems,
including soft lags of $\sim$30 $\mu$s between the 3.0 - 8.0 keV and 8.0 - 20.0
keV energy bands at the average QPO frequency. We also find lags that show a
nearly monotonic trend with energy, with the highest energy photons arriving
first. The covariance spectrum of the lower kHz QPO is well fit by a thermal
Comptonization model, though we find a higher seed photon temperature compared
to the mean spectrum, which was also seen in Peille et al., (2015), and
indicates the possibility of a composite boundary layer emitting region.
Lastly, we see in one set of observations, an Fe K component in the covariance
spectrum at 2.4-$\sigma$ confidence which may raise questions about the role of
reverberation in the production of lags.


title: Seismology of an Ensemble of ZZ Ceti Stars

abstract:
  We combine all the reliably-measured eigenperiods for hot, short-period ZZ
Ceti stars onto one diagram and show that it has the features expected from
evolutionary and pulsation theory. To make a more detailed comparison with
theory we concentrate on a subset of 16 stars for which rotational splitting or
other evidence gives clues to the spherical harmonic index (l) of the modes.
The suspected l=1 periods in this subset of stars form a pattern of consecutive
radial overtones that allow us to conduct ensemble seismology using published
theoretical model grids. We find that the best-matching models have hydrogen
layer masses most consistent with the canonically thick limit calculated from
nuclear burning. We also find that the evolutionary models with masses and
temperatures from spectroscopic fits cannot correctly reproduce the periods of
the k=1 to 4 mode groups in these stars, and speculate that the mass of the
helium layer in the models is too large.


title:
Diffusion of an Enzyme: the Role of Fluctuation-Induced Hydrodynamic
  Coupling

abstract:
  The effect of conformational fluctuations of modular macromolecules, such as
enzymes, on their diffusion properties is addressed using a simple generic
model of an asymmetric dumbbell made of two hydrodynamically coupled subunits.
It is shown that equilibrium fluctuations can lead to an interplay between the
internal and the external degrees of freedom and give rise to negative
contributions to the overall diffusion coefficient. Considering that this model
enzyme explores a mechanochemical cycle, we show how substrate binding and
unbinding affects its internal fluctuations, and how this can result in an
enhancement of the overall diffusion coefficient of the molecule. These
theoretical predictions are successfully confronted with recent measurements of
enzyme diffusion in dilute conditions using fluorescence correlation
spectroscopy.


title:
Analytical formulation for the bend-loss in single-ring hollow-core
  photonic crystal fibers

abstract:
  Understanding bend-loss in single-ring hollow-core photonic crystal fibers is
becoming of increasing importance as the fibers enter practical applications.
While purely numerical approaches are useful, there is a need for a simpler
analytical formalism that provides physical insight and can be directly used in
the design of PCFs with low bend-loss. We show theoretically and experimentally
that a wavelength-dependent critical bend radius exists below which the
bend-loss reaches a maximum, and that this can be calculated from the
structural parameters of a fiber using a simple analytical formula. This allows
straightforward design of single-ring PCFs that are bend-insensitive for
specified ranges of bend radius and wavelength. It also can be used to derive
an expression for the bend radius that yields optimal higher-order mode
suppression for a given fiber structure.


title: An inverse Jacobian algorithm for Picard curves

abstract:
  We study the inverse Jacobian problem for the case of Picard curves over
$\mathbb{C}$. More precisely, we elaborate on an algorithm that, given a small
period matrix $\Omega\in \mathbb{C}^{3\times 3}$ corresponding to a principally
polarized abelian threefold equipped with an automorphism of order $3$, returns
a Legendre-Rosenhain equation for a Picard curve with Jacobian isomorphic to
the given abelian variety.
  Our method corrects a formula obtained by Koike-Weng in [Math. Comp.,
74(249):499-518, 2005] which is based on a theorem of Siegel. As a result, we
apply the algorithm to obtain (numerically) all the isomorphism classes of
Picard curves with maximal complex multiplication attached to the sextic
CM-fields with class number at most $4$. In particular, we obtain
(conjecturally) the complete list of CM Picard curves defined over
$\mathbb{Q}$.
  In the appendix, Vincent gives a correction to the generalization of Takase's
formula for the inverse Jacobian problem for hyperelliptic curves given in
[Balakrishnan-Ionica-Lauter-Vincent, LMS J. Comput. Math., 19(suppl.
A):283-300, 2016].


title:
A logistic regression analysis approach for sample survey data based on
  phi-divergence measures

abstract:
  A new family of minimum distance estimators for binary logistic regression
models based on $\phi$-divergence measures is introduced. The so called "pseudo
minimum phi-divergence estimator"(PM$\phi$E) family is presented as an
extension of "minimum phi-divergence estimator" (M$\phi$E) for general sample
survey designs and contains, as a particular case, the pseudo maximum
likelihood estimator (PMLE) considered in Roberts et al. \cite{r}. Through a
simulation study it is shown that some PM$\phi$Es have a better behaviour, in
terms of efficiency, than the PMLE.


title: Local affine selections of convex multifunctions

abstract:
  It is well known that not every convex multifunction admits an affine
selection. One could ask whether there exists at least local affine selection.
The answer is positive in the finite-dimensional case. The main part of this
note consists of two examples of non-existence of local affine selections of
convex multifunctions defined on certain infinite-dimensional Banach spaces.


title: Necessary Adiabatic Run Times in Quantum Optimization

abstract:
  Quantum annealing is guaranteed to find the ground state of optimization
problems in the adiabatic limit. Recent work [Phys. Rev. X 6, 031010 (2016)]
has found that for some barrier tunneling problems, quantum annealing can be
run much faster than is adiabatically required. Specifically, an $n$-qubit
optimization problem was presented for which a non-adiabatic, or diabatic,
annealing algorithm requires only constant runtime, while an adiabatic
annealing algorithm requires a runtime polynomial in $n$.
  Here we show that this non-adiabatic speed-up is a direct result of a
specific symmetry in the studied problems. In the more general case, no such
non-adiabatic speed-up occurs. We furthermore show why the special case
achieves this speed-up compared to the general case. We conclude with the
observation that the adiabatic annealing algorithm has a necessary and
sufficient runtime that is quadratically better than the standard quantum
adiabatic condition suggests.


title:
Can the periodic spectral modulations of the 236 SETI candidate Sloan
  Survey stars be due to Dark Matter effects?

abstract:
  The search for dark matter (DM) is one of the most active and challenging
areas of current research. Possible DM candidates are ultralight fields such as
axions and weak interacting massive particles (WIMPs). Axions piled up in the
center of stars are supposed to generate matter/DM configurations with
oscillating geometries at a very rapid frequency, which is a multiple of the
axion mass $m_B$ [1,2]. Borra and Trottier recently found peculiar ultrafast
periodic spectral modulations in $236$ main sequence stars in the sample of
$2.5$ million spectra of galactic halo stars of the Sloan Digital Sky Survey
that were interpreted as optical signals from extraterrestrial civilizations,
possible candidates for the search for extraterrestrial intelligence (SETI)
program [3]. We argue, instead, that this could be the first indirect evidence
of bosonic axion-like DM fields inside main sequence stars, with a stable
radiative nucleus, where a stable DM core can be hosted. These oscillations
were not observed in earlier stellar spectral classes probably because of the
impossibility of starting a stable oscillatory regime due to the presence of
chaotic motions in their convective nuclei. The axion mass values, $(50 < m_B <
2.4 \times 10^{3})~ \mathrm{\mu eV}$, obtained from the frequency range
observed by Borra and Trottier, $(0.6077< f <0.6070$) THz, agree with the
recent theoretical results from high-temperature lattice quantum chromodynamics
[4,5].


title: On the second cohomology of nilpotent orbits in exceptional Lie algebras

abstract:
  In this paper we consider non-compact non-complex exceptional Lie algebras,
and compute the dimensions of the second cohomology groups for most of the
nilpotent orbits. For the rest of cases of nilpotent orbits, which are not
covered in the above computations, we obtain upper bounds for the dimensions of
the second cohomology groups.


title: Contradiction Detection for Rumorous Claims

abstract:
  The utilization of social media material in journalistic workflows is
increasing, demanding automated methods for the identification of mis- and
disinformation. Since textual contradiction across social media posts can be a
signal of rumorousness, we seek to model how claims in Twitter posts are being
textually contradicted. We identify two different contexts in which
contradiction emerges: its broader form can be observed across independently
posted tweets and its more specific form in threaded conversations. We define
how the two scenarios differ in terms of central elements of argumentation:
claims and conversation structure. We design and evaluate models for the two
scenarios uniformly as 3-way Recognizing Textual Entailment tasks in order to
represent claims and conversation structure implicitly in a generic inference
model, while previous studies used explicit or no representation of these
properties. To address noisy text, our classifiers use simple similarity
features derived from the string and part-of-speech level. Corpus statistics
reveal distribution differences for these features in contradictory as opposed
to non-contradictory tweet relations, and the classifiers yield state of the
art performance.


title:
An Optimal Ancestry Labeling Scheme with Applications to XML Trees and
  Universal Posets

abstract:
  In this paper we solve the ancestry-labeling scheme problem which aims at
assigning the shortest possible labels (bit strings) to nodes of rooted trees,
so that ancestry queries between any two nodes can be answered by inspecting
their assigned labels only. This problem was introduced more than twenty years
ago by Kannan et al. [STOC '88], and is among the most well-studied problems in
the field of informative labeling schemes. We construct an ancestry-labeling
scheme for $n$-node trees with label size $\log_2 n + O(\log \log n)$ bits,
thus matching the $\log_2 n + O(\log \log n)$ bits lower bound given by Alstrup
et al. [SODA '03]. Our scheme is based on a simplified ancestry scheme that
operates extremely well on a restricted set of trees. In particular, for the
set of n-node trees with depth at most d, the simplified ancestry scheme enjoys
label size of $\log_2 n + 2 \log_2 d + O(1)$ bits. Since the depth of most XML
trees is at most some small constant, such an ancestry scheme may be of
practical use. In addition, we also obtain an adjacency-labeling scheme that
labels n-node trees of depth d with labels of size $\log_2 n + 3 \log_2 d +
O(1)$ bits. All our schemes assign the labels in linear time, and guarantee
that any query can be answered in constant time. Finally, our ancestry scheme
finds applications to the construction of small universal partially ordered
sets (posets). Specifically, for any fixed integer k, it enables the
construction of a universal poset of size $\tilde O(n^k)$ for the family of
$n$-element posets with tree-dimension at most $k$. Up to lower order terms,
this bound is tight thanks to a lower bound of $n^{k-o(1)}$ due to Alon and
Scheinerman [Order '88].


title: Veracity Computing from Lexical Cues and Perceived Certainty Trends

abstract:
  We present a data-driven method for determining the veracity of a set of
rumorous claims on social media data. Tweets from different sources pertaining
to a rumor are processed on three levels: first, factuality values are assigned
to each tweet based on four textual cue categories relevant for our journalism
use case; these amalgamate speaker support in terms of polarity and commitment
in terms of certainty and speculation. Next, the proportions of these lexical
cues are utilized as predictors for tweet certainty in a generalized linear
regression model. Subsequently, lexical cue proportions, predicted certainty,
as well as their time course characteristics are used to compute veracity for
each rumor in terms of the identity of the rumor-resolving tweet and its binary
resolution value judgment. The system operates without access to
extralinguistic resources. Evaluated on the data portion for which hand-labeled
examples were available, it achieves .74 F1-score on identifying rumor
resolving tweets and .76 F1-score on predicting if a rumor is resolved as true
or false.


title: Higher cyclic operads

abstract:
  We introduce a convenient definition for weak cyclic operads, which is based
on unrooted trees and Segal conditions. More specifically, we introduce a
category $\Xi$ of trees, which carries a tight relationship to the
Moerdijk-Weiss category of rooted trees $\Omega$. We prove a nerve theorem
exhibiting colored cyclic operads as presheaves on $\Xi$ which satisfy a Segal
condition. Finally, we produce a Quillen model category whose fibrant objects
satisfy a weak Segal condition, and we consider these objects as an
up-to-homotopy generalization of the concept of cyclic operad.


title: Prediction of positive parity $B_s$ mesons and search for the $X(5568)$

abstract:
  We use a combination of quark-antiquark and $B^{(*)}K$ interpolating fields
to predict the mass of two QCD bound states below the $B^*K$ threshold in the
quantum channels $J^P=0^+$ and $1^+$. The mesons correspond to the b-quark
cousins of the $D_{s0}^*(2317)$ and $D_{s1}(2460)$ and have not yet been
observed in experiment, even though they are expected to be found by LHCb. In
addition to these predictions, we obtain excellent agreement of the remaining
p-wave energy levels with the known $B_{s1}(5830)$ and $B_{s2}^*(5840)$ mesons.
The results from our first principles calculation are compared to previous
model-based estimates. More recently the D0 collaboration claimed the existence
of an exotic resonance $X(5568)$ with exotic flavor content $\bar{b}s\bar{d}u$.
If such a state with $J^P=0^+$ exists, only the decay into $B_s\pi$ is open
which makes a lattice search for this state much cleaner and simpler than for
other exotic candidates involving heavy quarks. We conclude, however, that we
do not find such a candidate in agreement with a recent LHCb result.


title: On the Lifetime of Metastable Metallic Hydrogen

abstract:
  The molecular phase of hydrogen converts to the atomic metallic phase at high
pressures estimated usually as 300 - 500 GPa. We analyze the decay of metallic
phase as the pressure is relieved below the transition one. The metallic state
is expected to be in the metastable long-lived state down to about 10 - 20 GPa
and decays instantly at the lower pressures. The pressure range of the
long-lived metastable state is directly associated with an impossibility to
produce a stable hydrogen molecule immersed into the electron liquid of high
density. For lower pressures, the nucleation of an electron-free cavity with
the energetically favorable hydrogen molecule inside cannot be suppressed with
the low ambient pressure.


title: A Coherent Quantum Annealer with Rydberg Atoms

abstract:
  There is a significant ongoing effort in realizing quantum annealing with
different physical platforms. The challenge is to achieve a fully programmable
quantum device featuring coherent adiabatic quantum dynamics. Here we show that
combining the well-developed quantum simulation toolbox for Rydberg atoms with
the recently proposed Lechner-Hauke-Zoller~(LHZ) architecture allows one to
build a prototype for a coherent adiabatic quantum computer with all-to-all
Ising interactions and, therefore, a novel platform for quantum annealing. In
LHZ a infinite-range spin-glass is mapped onto the low energy subspace of a
spin-1/2 lattice gauge model with quasi-local 4-body parity constraints. This
spin model can be emulated in a natural way with Rubidium and Cesium atoms in a
bipartite optical lattice involving laser-dressed Rydberg-Rydberg interactions,
which are several orders of magnitude larger than the relevant decoherence
rates. This makes the exploration of coherent quantum enhanced optimization
protocols accessible with state-of-the-art atomic physics experiments.


title: Affine translation surfaces in the isotropic 3-space

abstract:
  The isotropic 3-space \mathbb{I}^{3} is a real affine 3-space endowed with
the metric dx^{2}+dy^{2}. In this paper we describe Weingarten and linear
Weingarten affine translation surfaces in \mathbb{I}^{3}. Further we classify
the affine translation surfaces in \mathbb{I}^{3} that satisfy certain
equations in terms of the position vector and the Laplace operator.


title:
SWARM: A 32 GHz Correlator and VLBI Beamformer for the Submillimeter
  Array

abstract:
  A 32 GHz bandwidth VLBI capable correlator and phased array has been designed
and deployed at the Smithsonian Astrophysical Observatory's Submillimeter Array
(SMA). The SMA Wideband Astronomical ROACH2 Machine (SWARM) integrates two
instruments: a correlator with 140 kHz spectral resolution across its full 32
GHz band, used for connected interferometric observations, and a phased array
summer used when the SMA participates as a station in the Event Horizon
Telescope (EHT) Very Long Baseline Interferometry (VLBI) array. For each SWARM
quadrant, Reconfigurable Open Architecture Computing Hardware (ROACH2) units
shared under open source from the Collaboration for Astronomy Signal Processing
and Electronics Research (CASPER) are equipped with a pair of ultra-fast
Analog-to- Digital Converters (ADCs), a Field Programmable Gate Array (FPGA)
processor, and eight 10 Gigabit Ethernet ports. A VLBI data recorder interface
designated the SWARM Digital Back End, or SDBE, is implemented with a ninth
ROACH2 per quadrant, feeding four Mark6 VLBI recorders with an aggregate
recording rate of 64 Gbps. This paper describes the design and implementation
of SWARM, as well as its deployment at SMA with reference to verification and
science data.


title:
Magnetic hyperthermia enhances cell toxicity with respect to exogenous
  heating

abstract:
  Magnetic hyperthermia is a new type of cancer treatment designed for
overcoming resistance to chemotherapy during the treatment of solid,
inaccessible human tumors. The main challenge of this technology is increasing
the local tumoral temperature with minimal side effects on the surrounding
healthy tissue. This work consists of an in vitro study that compared the
effect of hyperthermia in response to the application of exogenous heating
(EHT) sources with the corresponding effect produced by magnetic hyperthermia
(MHT) at the same target temperatures. Human neuroblastoma SH-SY5Y cells were
loaded with magnetic nanoparticles (MNPs) and packed into dense pellets to
generate an environment that is crudely similar to that expected in solid
micro-tumors, and the above-mentioned protocols were applied to these cells.
These experiments showed that for the same target temperatures, MHT induces a
decrease in cell viability that is larger than the corresponding EHT, up to a
maximum difference of approximately 45\% at T = 46{\deg}C. An analysis of the
data in terms of temperature efficiency demonstrated that MHT requires an
average temperature that is 6{\deg}C lower than that required with EHT to
produce a similar cytotoxic effect. An analysis of electron microscopy images
of the cells after the EHT and MHT treatments indicated that the enhanced
effectiveness observed with MHT is associated with local cell destruction
triggered by the magnetic nano-heaters. The present study is an essential step
toward the development of innovative adjuvant anti-cancer therapies based on
local hyperthermia treatments using magnetic particles as nano-heaters.