title: The PCA Lens-Finder: application to CFHTLS

abstract:
  We present the results of a new search for galaxy-scale strong lensing
systems in CFHTLS Wide. Our lens-finding technique involves a preselection of
potential lens galaxies, applying simple cuts in size and magnitude. We then
perform a Principal Component Analysis of the galaxy images, ensuring a clean
removal of the light profile. Lensed features are searched for in the residual
images using the clustering topometric algorithm DBSCAN. We find 1098 lens
candidates that we inspect visually, leading to a cleaned sample of 109 new
lens candidates. Using realistic image simulations we estimate the completeness
of our sample and show that it is independent of source surface brightness,
Einstein ring size (image separation) or lens redshift. We compare the
properties of our sample to previous lens searches in CFHTLS. Including the
present search, the total number of lenses found in CFHTLS amounts to 678,
which corresponds to ~4 lenses per square degree down to i=24.8. This is
equivalent to ~ 60.000 lenses in total in a survey as wide as Euclid, but at
the CFHTLS resolution and depth.


title:
Dependence of Small Planet Frequency on Stellar Metallicity Hidden by
  Their Prevalence

abstract:
  The dependence of gas giant planet occurrence rate on stellar metallicity has
been firmly established. We extend this so-called planet-metallicity
correlation to broader ranges of metallicities and planet masses/radii. In
particular, we assume that the planet-metallicity correlation is a power law
below some critical saturation threshold, and that the probability of hosting
at least one planet is unity for stars with metallicity above the threshold. We
then are able to explain the discrepancy between the tentative detection and
null detection in previous studies regarding the planet-metallicity correlation
for small planets. In particular, we find that the null detection of this
correlation can be attributed to the combination of high planet occurrence rate
and low detection efficiency. Therefore, a planet-metallicity correlation for
small planets cannot be ruled out. We propose that stars with metallicities
lower than the Solar value are better targets for testing the
planet-metallicity correlation for small planets.


title:
Constraining the top-Higgs sector of the Standard Model Effective Field
  Theory

abstract:
  Working in the framework of the Standard Model Effective Field Theory, we
study chirality-flipping couplings of the top quark to Higgs and gauge bosons.
We discuss in detail the renormalization group evolution to lower energies and
investigate direct and indirect contributions to high- and low-energy
CP-conserving and CP-violating observables. Our analysis includes constraints
from collider observables, precision electroweak tests, flavor physics, and
electric dipole moments. We find that indirect probes are competitive or
dominant for both CP-even and CP-odd observables, even after accounting for
uncertainties associated with hadronic and nuclear matrix elements,
illustrating the importance of including operator mixing in constraining the
Standard Model Effective Field Theory. We also study scenarios where multiple
anomalous top couplings are generated at the high scale, showing that while the
bounds on individual couplings relax, strong correlations among couplings
survive. Finally, we find that enforcing minimal flavor violation does not
significantly affect the bounds on the top couplings.


title:
Unitarity, Feedback, Interactions -- Dynamics Emergent from Repeated
  Measurements

abstract:
  Motivated by the recent efforts to describe the gravitational interaction as
a classical channel arising from continuous quantum measurements, we study what
types of dynamics can emerge from a collisional model of repeated interactions
between a system and a set of ancillae. We show that contingent on the model
parameters the resulting dynamics ranges from exact unitarity to arbitrarily
fast decoherence (quantum Zeno effect). For a series of measurements the
effective dynamics includes feedback-control, which for a composite system
yields effective interactions between the subsystems. We quantify the amount of
decoherence accompanying such induced interactions, generalizing the lower
bound found for the gravitational example. However, by allowing multipartite
measurements, we show that interactions can be induced with arbitrarily low
decoherence. These results have implications for gravity-inspired decoherence
models. Moreover, we show how the framework can include terms beyond the usual
second-order approximation, which can spark new quantum control or simulation
protocols. Finally, within our simple approach we re-derive the quantum
filtering equations for the different regimes of effective dynamics, which can
facilitate new connections between different formulations of open systems.


title: ASASSN-16ae: A Powerful White-Light Flare on an Early-L Dwarf

abstract:
  We report the discovery and classification of SDSS~J053341.43+001434.1
(SDSS0533), an early-L dwarf first discovered during a powerful $\Delta V <
-11$ magnitude flare observed as part of the ASAS-SN survey. Optical and
infrared spectroscopy indicate a spectral type of L0 with strong H$\alpha$
emission and a blue NIR spectral slope. Combining the photometric distance,
proper motion, and radial velocity of SDSS0533 yields three-dimensional
velocities of $(U,V,W)=(14\pm13,-35\pm14,-94\pm22)$~km~s$^{-1}$, indicating
that it is most likely part of the thick disk population and probably old. The
three detections of SDSS0533 obtained during the flare are consistent with a
total $V$-band flare energy of at least $4.9\times10^{33}$~ergs (corresponding
to a total thermal energy of at least $E_{\rm tot}>3.7\times10^{34}$~erg),
placing it among the strongest detected M dwarf flares. The presence of this
powerful flare on an old L0 dwarf may indicate that stellar-type magnetic
activity persists down to the end of the main sequence and on older ML
transition dwarfs.


title:
A Tight Relation Between N/O Ratio and Galaxy Stellar Mass Can Explain
  the Evolution of Strong Emission Line Ratios with Redshift

abstract:
  The offset of high redshift star-forming galaxies in the [OIII]/H$\beta$
versus [NII]/H$\alpha$ (O3N2) diagram in comparison with the local star-forming
galaxy sequence is now well established. The physical origin of the shift is
the subject of some debate, and has important implications for metallicity
measurements based on strong lines at all redshifts. To investigate the origin
of the O3N2 offset, we use a sample of ~100,000 star-forming galaxies from SDSS
DR12 to probe the empirical correlations between emission line diagnostics and
measurable galaxy physical properties. In particular, we examine how surface
density of star formation, ionization parameter, nitrogen-to-oxygen (N/O)
ratio, and stellar mass drive position in two key diagnostic diagrams: O3N2 and
[OIII]/H$\beta$ versus [SII]/H$\alpha$ (O3S2). We show that, at fixed
[OIII]/H$\beta$, galaxies falling closer to the high-redshift locus in O3N2
have higher star formation density, stellar mass and N/O ratios. We also find a
tight correspondence in the distributions of stellar mass and N/O in the
diagnostic diagrams. This relation, spanning a range of galaxy evolutionary
states, suggests that the N/O-$M_{*}$ relation is more fundamental than the
N/O-metallicity relation. We argue that a tight N/O-$M_{*}$ relation is
well-motivated physically, and that the observed correlation of N/O with O/H in
the local universe is primarily a reflection of the existence of the
mass-metallicity relation. Because the mass-metallicity relation evolves much
more rapidly with redshift than N/O-$M_{*}$, the N/O ratios of high redshift
galaxies are significantly elevated in comparison with local galaxies with the
same gas-phase O/H. The O3N2 shift and elevated N/O ratios observed in high
redshift galaxies therefore come about as a natural consequence of the
N/O-$M_{*}$ relation combined with the evolution of the mass-metallicity
relation.


title:
Kitaev honeycomb tensor networks: exact unitary circuits and
  applications

abstract:
  The Kitaev honeycomb model is a paradigm of exactly-solvable models, showing
non-trivial physical properties such as topological quantum order, abelian and
non-abelian anyons, and chirality. Its solution is one of the most beautiful
examples of the interplay of different mathematical techniques in condensed
matter physics. In this paper, we show how to derive a tensor network (TN)
description of the eigenstates of this spin-1/2 model in the thermodynamic
limit, and in particular for its ground state. In our setting, eigenstates are
naturally encoded by an exact 3d TN structure made of fermionic unitary
operators, corresponding to the unitary quantum circuit building up the
many-body quantum state. In our derivation we review how the different
"solution ingredients" of the Kitaev honeycomb model can be accounted for in
the TN language, namely: Jordan-Wigner transformation, braidings of Majorana
modes, fermionic Fourier transformation, and Bogoliubov transformation. The TN
built in this way allows for a clear understanding of several properties of the
model. In particular, we show how the fidelity diagram is straightforward both
at zero temperature and at finite temperature in the vortex-free sector. We
also show how the properties of two-point correlation functions follow easily.
Finally, we also discuss the pros and cons of contracting of our 3d TN down to
a 2d Projected Entangled Pair State (PEPS) with finite bond dimension. The
results in this paper can be extended to generalizations of the Kitaev model,
e.g., to other lattices, spins, and dimensions.


title:
Locating the quantum critical point of the Bose-Hubbard model through
  singularities of simple observables

abstract:
  We show that the critical point of the two-dimensional Bose-Hubbard model can
be easily found through studies of either on-site atom number fluctuations or
the nearest-neighbor two-point correlation function (the expectation value of
the tunnelling operator). Our strategy to locate the critical point is based on
the observation that the derivatives of these observables with respect to the
parameter that drives the superfluid-Mott insulator transition are singular at
the critical point in the thermodynamic limit. Performing the quantum Monte
Carlo simulations of the two-dimensional Bose-Hubbard model, we show that this
technique leads to the accurate determination of the position of its critical
point. Our results can be easily extended to the three-dimensional Bose-Hubbard
model and different Hubbard-like models. They provide a simple
experimentally-relevant way of locating critical points in various cold atomic
lattice systems.


title:
fastRESOLVE: fast Bayesian imaging for aperture synthesis in radio
  astronomy

abstract:
  The standard imaging algorithm for interferometric radio data, CLEAN, is
optimal for point source observations, but suboptimal for diffuse emission.
Recently, RESOLVE, a new Bayesian algorithm has been developed, which is ideal
for extended source imaging. Unfortunately, RESOLVE is computationally very
expensive. In this paper we present fastRESOLVE, a modification of RESOLVE
based on an approximation of the interferometric likelihood that allows us to
avoid expensive gridding routines and consequently gain a factor of roughly 100
in computation time. Furthermore, we include a Bayesian estimation of the
measurement uncertainty of the visibilities into the imaging, a procedure not
applied in aperture synthesis before. The algorithm requires little to no user
input compared to the standard method CLEAN while being superior for extended
and faint emission. We apply the algorithm to VLA data of Abell 2199 and show
that it resolves more detailed structures.


title: Magnetic Influences on the Solar Wind (Ph.D. Dissertation)

abstract:
  The steady, supersonic outflow from the Sun we call the solar wind was first
posited in the 1950s and initial theories rightly linked the acceleration of
the wind to the existence of the million-degree solar corona. Still today, the
wind acceleration mechanisms and the coronal heating processes remain unsolved
challenges in solar physics. In this work, I seek to answer a portion of the
mystery by focusing on a particular acceleration process: Alfven waves launched
by the motion of magnetic field footpoints in the photosphere. The entire
corona is threaded with magnetic loops and flux tubes that open up into the
heliosphere. I have sought a better understanding of the role these magnetic
fields play in determining solar wind properties in open flux tubes. After an
introduction of relevant material, I discuss my parameter study of magnetic
field profiles and the statistical understanding we can draw from the resulting
steady-state wind. In the chapter following, I describe how I extended this
work to consider time dependence in the turbulent heating by Alfven waves in
three dimensional simulations. The bursty nature of this heating led to a
natural next step that expands my work to include not only the theoretical, but
also a project to analyze observations of small network jets in the
chromosphere and transition region, and the underlying photospheric magnetic
field that forms thresholds in jet production. In summary, this work takes a
broad look at the extent to which Alfven-wave-driven turbulent heating can
explain measured solar wind properties and other observed phenomena.


title:
A look to the inside of haloes: a characterisation of the halo shape as
  a function of overdensity in the Planck cosmology

abstract:
  In this paper we study the triaxial properties of dark matter haloes of a
wide range of masses extracted from a set of cosmological N-body simulations.
We measure the shape at different distances from the halo centre (characterised
by different overdensity thresholds), both in three and in two dimensions. We
discuss how halo triaxiality increases with mass, redshift and distance from
the halo centre. We also examine how the orientation of the different
ellipsoids are aligned with each other and what is the gradient in internal
shapes for halos with different virial configurations. Our findings highlight
that the internal part of the halo retains memory of the violent formation
process keeping the major axis oriented toward the preferential direction of
the in-falling material while the outer part becomes rounder due to continuous
isotropic merging events. This effect is clearly evident in high mass haloes -
which formed more recently - while it is more blurred in low mass haloes. We
present simple distributions that may be used as priors for various mass
reconstruction algorithms, operating in different wavelengths, in order to
recover a more complex and realistic dark matter distribution of isolated and
relaxed systems.


title: On the improvement of cosmological neutrino mass bounds

abstract:
  The most recent measurements of the temperature and low-multipole
polarization anisotropies of the Cosmic Microwave Background (CMB) from the
Planck satellite, when combined with galaxy clustering data from the Baryon
Oscillation Spectroscopic Survey (BOSS) in the form of the full shape of the
power spectrum, and with Baryon Acoustic Oscillation measurements, provide a
$95\%$ confidence level (CL) upper bound on the sum of the three active
neutrinos $\sum m _\nu< 0.183$ eV, among the tightest neutrino mass bounds in
the literature, to date, when the same datasets are taken into account. This
very same data combination is able to set, at $\sim70\%$ CL, an upper limit on
$\sum m _\nu$ of $0.0968$ eV, a value that approximately corresponds to the
minimal mass expected in the inverted neutrino mass hierarchy scenario. If
high-multipole polarization data from Planck is also considered, the $95\%$ CL
upper bound is tightened to $\sum m _\nu< 0.176$ eV. Further improvements are
obtained by considering recent measurements of the Hubble parameter. These
limits are obtained assuming a specific non-degenerate neutrino mass spectrum;
they slightly worsen when considering other degenerate neutrino mass schemes.
Current cosmological data, therefore, start to be mildly sensitive to the
neutrino mass ordering. Low-redshift quantities, such as the Hubble constant or
the reionization optical depth, play a very important role when setting the
neutrino mass constraints. We also comment on the eventual shifts in the
cosmological bounds on $\sum m_\nu$ when possible variations in the former two
quantities are addressed.


title: Generalized Delta Functions and Their Use in Quantum Optics

abstract:
  The Dirac delta function is widely used in many areas of physics and
mathematics. Here we consider the generalization of a Dirac delta function to
allow the use of complex arguments. We show that the properties of a
generalized delta function are very different from those of a Dirac delta
function and that they behave more like a pole in the complex plane. We use the
generalized delta function to derive the Glauber-Sudarshan P-function for a
Schr\"odinger cat state in a surprisingly simple form. Aside from their
potential applications in classical electromagnetism and quantum optics, these
results provide insight into the ability of the diagonal P-function to describe
density operators with off-diagonal elements.


title: Doubling bialgebras of graphs and feynman rules

abstract:
  In this article, we define a doubling procedure for the bialgebra of
specified Feynman graphs introduced in a previous paper \cite {DMB}. This is
the vector space generated by the pairs $(\bar \Gamma, \bar \gamma)$ where
$\bar \Gamma$ is a locally $1PI$ specified graph of a perturbation theory $\Cal
T$ with $\bar \gamma \subset \bar \Gamma$ locally $1PI$ and where $\bar \Gamma
/ \bar \gamma $ is a specified graph of $\Cal T$. We also define a convolution
product on the characters of this new bialgebra with values in an endomorphism
algebra, equipped with a commutative product compatible with the composition.
We then express in this framework the renormalization as formulated by A.
Smirnov \cite [\S 8.5, 8.6] {Sm}, adapting the approach of A. Connes and D.
Kreimer for two renormalization schemes: the minimal renormalization scheme and
the Taylor expansion scheme. Finally, we determine the finite parts of Feynman
integrals using the BPHZ algorithm after dimensional regularization procedure,
by following the approach by P. Etingof \cite{PE} (see also \cite{RM}).


title: Error Probabilities for Halfspace Depth

abstract:
  Data depth functions are a generalization of one-dimensional order statistics
and medians to real spaces of dimension greater than one; in particular, a data
depth function quantifies the centrality of a point with respect to a data set
or a probability distribution. One of the most commonly studied data depth
functions is halfspace depth. It is of interest to computational geometers
because it is highly geometric, and it is of interest to statisticians because
it shares many desirable theoretical properties with the one-dimensional
median. As the sample size increases, the halfspace depth for a sample
converges to the halfspace depth for the underlying distribution, almost
surely. In this paper, we use the geometry of halfspace depth to improve the
explicit bounds on the rate of convergence.


title:
Quantizing the Vector Potential Reveals Alternative Views of the
  Magnetic Aharonov-Bohm Phase Shift

abstract:
  We give a complete quantum analysis of the Aharonov-Bohm (AB) magnetic phase
shift involving three entities, the electron, the charges constituting the
solenoid current, and the vector potential. The usual calculation supposes that
the solenoid's vector potential may be well-approximated as classical. The AB
shift is then acquired by the quantized electron moving in this vector
potential. Recently, Vaidman presented a semi-classical calculation, later
confirmed by a fully quantum calculation of Pearle and Rizzi, where it is
supposed that the electron's vector potential may be well-approximated as
classical. The AB shift is then acquired by the quantized solenoid charges
moving in this vector potential. Here we present a third calculation, which
supposes that the electron and solenoid currents may be well-approximated as
classical sources. The AB phase shift is then shown to be acquired by the
quantized vector potential. We next show these are three equivalent alternative
ways of calculating the AB shift. We consider the exact problem where all three
entities are quantized. We approximate the wave function as the product of
three wave functions, a vector potential wave function, an electron wave
function and a solenoid wave function. We apply the variational principle for
the exact Schrodinger equation to this approximate form of solution. This leads
to three Schrodinger equations, one each for vector potential, electron and
solenoid, each with classical sources for the other two entities. However, each
Schrodinger equation contains an additional real c-number term, the time
derivative of an extra phase. We show that these extra phases are such that the
net phase of the total wave function produces the AB shift. Since none of the
three entities requires different treatment from any of the others, this leads
to three alternative views of the physical cause of the AB magnetic effect.


title:
Unveiling Majorana Quasiparticles by a Quantum Phase Transition:
  Proposal of a Current Switch

abstract:
  We propose a theoretical approach based on an interferometer composed by two
quantum dots asymmetrically coupled to isolated Majorana quasiparticles (MQPs),
lying on the edges of two topological Kitaev chains, respectively via couplings
$(t+\Delta)$ and $(\Delta-t)$. This setup enables us to probe MQPs in a quite
distinct way from the zero-bias peak feature. Most importantly, the system
behaves as a current switch made by two distinct paths: (i) for the upper dot
connected to both chains, the device perceives both MQPs as an ordinary fermion
and the current crosses solely the lower dot, since current in the upper dot is
prevented due to the presence of the superconducting gap; and (ii) by
suppressing slightly the hybridization of the upper dot with one chain, the
current is abruptly switched to flow through this dot, once a trapped electron
as a bound state in the continuum (BIC) (Phys. Rev. B 93, 165116 (2016))
appears in the lower dot. Such a current switch between upper and lower dots
characterizes the Quantum Phase Transition (QPT) proposed here, being the ratio
$t/\Delta$ the control parameter of the transition. This QPT is associated with
a change from an ordinary fermionic excitation regime to a MQP in the
interferometer, which enables not only the fundamental revealing of MQPs, but
also yields a current switch assisted by them.


title:
An inequality for longitudinal and transverse wave attenuation
  coefficients

abstract:
  Total absorption, defined as the net flux of energy out of a bounded region
averaged over one cycle for time harmonic motion, must be non-negative when
there are no sources of energy within the region. This passivity condition
places constraints on the non-dimensional absorption coefficients of
longitudinal and transverse waves, $\gamma_L$ and $\gamma_T$, in isotropic
linearly viscoelastic materials. Typically, $\gamma_L, \, \gamma_T$ are small,
in which case the constraints imply that coefficients of attenuation per unit
length, $\alpha_L$, $\alpha_T$, must satisfy the inequality
${\alpha_L}/{\alpha_T} \ge { 4c_{T}^3} / { 3c_{L}^3}$ where $c_L$, $c_T$ are
the wave speeds. This inequality, which as far as the author is aware, has not
been presented before, provides a relative bound on wave speed in terms of
attenuation, or {\it vice versa}. It also serves as a check on the consistency
of ultrasonic measurements from the literature, with most but not all of the
data considered passing the positive absorption test.


title: Analytic study of a coupled Kerr-SBS system

abstract:
  In order to describe the coupling between the Kerr nonlinearity and the
stimulated Brillouin scattering, Mauger et alii recently proposed a system of
partial differential equations in three complex amplitudes. We perform here its
analytic study by two methods. The first method is to investigate the structure
of singularities, in order to possibly find closed form singlevalued solutions
obeying this structure. The second method is to look at the infinitesimal
symmetries of the system in order to build reductions to a lesser number of
independent variables. Our overall conclusion is that the structure of
singularities is too intricate to obtain closed form solutions by the usual
methods. One of our results is the proof of the nonexistence of traveling
waves.


title: Identification and Analysis of Transition and Metastable Markov States

abstract:
  We present a new method that enables the identification and analysis of both
transition and metastable conformational states from atomistic or
coarse-grained molecular dynamics (MD) trajectories. Our algorithm is presented
and studied by using both analytical and actual examples from MD simulations of
the helix-forming peptide Ala5, and of a larger system, the epidermal growth
factor receptor (EGFR) protein. In all cases, our method identifies
automatically the corresponding transition states and metastable conformations
in an optimal way, with the input of a set of relevant coordinates, by
capturing accurately the intrinsic slowest relaxation rate. Our approach
provides a general and easy to implement analysis method that provides unique
insight into the molecular mechanism and the rare but crucial rate limiting
conformational pathways occurring in complex dynamical systems such as
molecular trajectories.


title: Critical dynamics at the Anderson localization mobility edge

abstract:
  We study the critical dynamics of matter waves at the 3D Anderson mobility
edge in cold-atom disorder quench experiments. General scaling arguments are
supported by precision numerics for the spectral function, diffusion
coefficient, and localization length in isotropic blue-detuned speckle
potentials. We discuss signatures of critical slowdown in the time-dependent
central column density of a spreading wave packet, and evaluate the prospects
of observing anomalous diffusion right at criticality.


title: Edge Cut Domination, Irredundance, and Independence in Graphs

abstract:
  An edge dominating set $F$ of a graph $G=(V,E)$ is an \textit{edge cut
dominating set} if the subgraph $\langle V,G-F \rangle$ is disconnected. The
\textit{edge cut domination number} $\gamma_{ct}(G)$ of $G$ is the minimum
cardinality of an edge cut dominating set of $G.$ In this paper we study the
edge cut domination number and investigate its relationships with other
parameters of graphs. We also introduce the properties edge cut irredundance
and edge cut independence.


title: Statistical properties of Cherenkov and quasi-Cherenkov superradiance

abstract:
  We consider the effects of shot noise and particle energy spread on
statistical properties of Cherenkov and quasi-Cherenkov superradiance emitted
by a relativistic electron beam. In the absence of energy spread, we have found
the root-mean-square deviations of both peak radiated power and instability
growth time as a function of the number of particles. It is shown that energy
spread can lead to a sharp drop in the radiated power of Cherenkov and
quasi-Cherenkov superradiance at high currents.


title:
Spectral Cauchy Characteristic Extraction of strain, news and
  gravitational radiation flux

abstract:
  We present a new approach for the Cauchy-characteristic extraction of
gravitational radiation strain, news function, and the flux of the
energy-momentum, supermomentum and angular momentum associated with the
Bondi-Metzner-Sachs asymptotic symmetries. In Cauchy-characteristic extraction,
a characteristic evolution code takes numerical data on an inner worldtube
supplied by a Cauchy evolution code, and propagates it outwards to obtain the
space-time metric in a neighborhood of null infinity. The metric is first
determined in a scrambled form in terms of coordinates determined by the Cauchy
formalism. In prior treatments, the waveform is first extracted from this
metric and then transformed into an asymptotic inertial coordinate system. This
procedure provides the physically proper description of the waveform and the
radiated energy but it does not generalize to determine the flux of angular
momentum or supermomentum. Here we formulate and implement a new approach which
transforms the full metric into an asymptotic inertial frame and provides a
uniform treatment of all the radiation fluxes associated with the asymptotic
symmetries. Computations are performed and calibrated using the Spectral
Einstein Code (SpEC).


title:
The rotation period distributions of 4--10 Myr T Tauri stars in Orion
  OB1: New constraints on pre-main-sequence angular momentum evolution

abstract:
  Most existing studies of the angular momentum evolution of young stellar
populations have focused on the youngest (1-3 Myr) T Tauri stars. In contrast,
the angular momentum distributions of older T Tauri stars (4-10 Myr) have been
less studied, even though they hold key insight to understanding stellar
angular momentum evolution at a time when protoplanetary disks have largely
dissipated and when models therefore predict changes in the rotational
evolution that can in principle be tested. We present a study of photometric
variability among 1,974 confirmed T Tauri members of various sub-regions of the
Orion OB1 association, and with ages spanning 4-10 Myr, using optical
time-series from three different surveys. For 564 of the stars (~32% of the
weak-lined T Tauri stars and ~13% of the classical T Tauri stars in our sample)
we detect statistically significant periodic variations which we attribute to
the stellar rotation periods, making this one of the largest samples of T Tauri
star rotation periods yet published. We observe a clear change in the overall
rotation period distributions over the age range 4-10 Myr, with the
progressively older sub-populations exhibiting systematically faster rotation.
This result is consistent with angular momentum evolution model predictions of
an important qualitative change in the stellar rotation periods starting at ~5
Myr, an age range for which very few observational constraints were previously
available.


title:
Fourier analysis of RGB fringe-projection profilometry and robust
  phase-demodulation methods against crosstalk distortion

abstract:
  In this paper we apply the frequency transfer function (FTF) formalism to
analyze the red, green and blue (RGB) phase-shifting fringe-projection
profilometry technique. The phase-shifted fringe patterns in RGB fringe
projection are typically corrupted by crosstalk because the sensitivity curves
of most projection-recording systems overlap. Crosstalk distortion needs to be
compensated in order to obtain high quality measurements. We study
phase-demodulation methods for null/mild, moderate, and severe levels of RGB
crosstalk. For null/mild crosstalk, we can estimate the searched phase-map
using Bruning's 3-step phase-shifting algorithm (PSA). For moderate crosstalk,
the RGB recorded data is usually preprocessed before feeding it into Bruning's
PSA; alternatively, in this paper we propose a computationally more efficient
approach, which combines crosstalk compensation and phase-demodulation into a
single process. For severe RGB crosstalk, we expect non-sinusoidal fringes'
profiles (distorting harmonics) and significant uncertainties on the crosstalk
calibration (which produces pseudo-detuning error). Analyzing these distorting
phenomena, we conclude that squeezing interferometry is the most robust
demodulation method for RGB fringe-projection techniques. We support our
conclusions with numerical simulations and experimental results.


title: New Insights into Quantum Gravity from Gauge/gravity Duality

abstract:
  Using gauge/gravity duality, we deduce several nontrivial consequences of
quantum gravity from simple properties of the dual field theory. These include:
(1) a version of cosmic censorship, (2) restrictions on evolution through black
hole singularities, and (3) the exclusion of certain cosmological bounces. In
the classical limit, the latter implies a new singularity theorem.


title: Nonlocal Drag of Magnons in a Ferromagnetic Bilayer

abstract:
  Quantized spin waves, or magnons, in a magnetic insulator are assumed to
interact weakly with the surroundings, and to flow with little dissipation or
drag, producing exceptionally long diffusion lengths and relaxation times. In
analogy to Coulomb drag in bilayer two dimensional electron gases, in which the
contribution of the Coulomb interaction to the electric resistivity is studied
by measuring the interlayer resistivity (transresistivity), we predict a
nonlocal drag of magnons in a ferromagnetic bilayer structure based on
semiclassical Boltzmann equations. Nonlocal magnon drag depends on magnetic
dipolar interactions between the layers and manifests in the magnon current
transresistivity and the magnon thermal transresistivity, whereby a magnon
current in one layer induces a chemical potential gradient and/or a temperature
gradient in the other layer. The largest drag effect occurs when the magnon
current flows parallel to the magnetization, however for oblique magnon
currents a large transverse current of magnons emerges. We examine the effect
for practical parameters, and find that the predicted induced temperature
gradient is readily observable.


title:
Support Vector Algorithms for Optimizing the Partial Area Under the ROC
  Curve

abstract:
  The area under the ROC curve (AUC) is a widely used performance measure in
machine learning. Increasingly, however, in several applications, ranging from
ranking to biometric screening to medicine, performance is measured not in
terms of the full area under the ROC curve, but in terms of the \emph{partial}
area under the ROC curve between two false positive rates. In this paper, we
develop support vector algorithms for directly optimizing the partial AUC
between any two false positive rates. Our methods are based on minimizing a
suitable proxy or surrogate objective for the partial AUC error. In the case of
the full AUC, one can readily construct and optimize convex surrogates by
expressing the performance measure as a summation of pairwise terms. The
partial AUC, on the other hand, does not admit such a simple decomposable
structure, making it more challenging to design and optimize (tight) convex
surrogates for this measure.
  Our approach builds on the structural SVM framework of Joachims (2005) to
design convex surrogates for partial AUC, and solves the resulting optimization
problem using a cutting plane solver. Unlike the full AUC, where the
combinatorial optimization needed in each iteration of the cutting plane solver
can be decomposed and solved efficiently, the corresponding problem for the
partial AUC is harder to decompose. One of our main contributions is a
polynomial time algorithm for solving the combinatorial optimization problem
associated with partial AUC. We also develop an approach for optimizing a
tighter non-convex hinge loss based surrogate for the partial AUC using
difference-of-convex programming. Our experiments on a variety of real-world
and benchmark tasks confirm the efficacy of the proposed methods.


title: Reversed Dickson polynomials of the (k+1)-th kind over finite fields

abstract:
  We discuss the properties and the permutation behaviour of the reversed
Dickson polynomials of the $(k+1)$-th kind $D_{n,k}(1,x)$ over finite fields.
The results in this paper unify and generalize several recently discovered
results on reversed Dickson polynomials over finite fields.


title: Reproducible and replicable CFD: it's harder than you think

abstract:
  Completing a full replication study of our previously published findings on
bluff-body aerodynamics was harder than we thought. Despite the fact that we
have good reproducible-research practices, sharing our code and data openly.
Here's what we learned from three years, four CFD codes and hundreds of runs.


title: The Maximum Block Size of Critical Random Graphs

abstract:
  Let $G(n,\, M)$ be the uniform random graph with $n$ vertices and $M$ edges.
Let $B_n$ be the maximum block-size of $G(n,\, M)$ or the maximum size of its
maximal $2$-connected induced subgraphs. We determine the expectation of $B_n$
near the critical point $M=n/2$. As $n-2M \gg n^{2/3}$, we find a constant
$c_1$ such that \[ c_1 = \lim_{n \rightarrow \infty} \left(1 - \frac{2M}{n}
\right) \, E B_n \, . \] Inside the window of transition of $G(n,\, M)$ with
$M=\frac{n}{2}(1+\lambda n^{-1/3})$, where $\lambda$ is any real number, we
find an exact analytic expression for \[ c_2(\lambda) = \lim_{n \rightarrow
\infty} \frac{E B_n} {n^{1/3}} \, . \] This study relies on the symbolic method
and analytic tools coming from generating function theory which enable us to
describe the evolution of $n^{-1/3} \, E B_n $ as a function of $\lambda$.


title: Extra-dimensional models on the lattice

abstract:
  In this review we summarize the ongoing effort to study extra-dimensional
gauge theories with lattice simulations. In these models the Higgs field is
identified with extra-dimensional components of the gauge field. The Higgs
potential is generated by quantum corrections and is protected from
divergencies by the higher dimensional gauge symmetry. Dimensional reduction to
four dimensions can occur through compactification or localization. Gauge-Higgs
unification models are often studied using perturbation theory. Numerical
lattice simulations are used to go beyond these perturbative expectations and
to include non-perturbative effects. We describe the known perturbative
predictions and their fate in the strongly-coupled regime for various
extra-dimensional models.


title: The pion electromagnetic structure with self-energy

abstract:
  We study the electromagnetic structure of the pion in terms of the quantum
cromodynamic~(QCD) model on the Breit-frame. We calculated the observables,
such as the electromagnetic form factor. The priori to have a calculation
covariant need to get the valence term of the eletromagnetic form factor. We
use the usual formalism in quantum field theory (QFT) and light-front quantum
field theory (LFQFT) in order to test the properties of form factor in
nonperturbative QCD. In this particular case, the form factor can be obtained
using the pion Light-Front (LF) wave function including self-energy from
Lattice-QCD. Specifically, these calculations was performed in LF formalism. We
consider a quark-antiquark vertex model having a quark self-energy. Also we can
use other models to compare the pion electromagnetic form factor with different
wave function and to observe the degree of agreement between them.


title:
A Relatively Small Turing Machine Whose Behavior Is Independent of Set
  Theory

abstract:
  Since the definition of the Busy Beaver function by Rado in 1962, an
interesting open question has been the smallest value of n for which BB(n) is
independent of ZFC set theory. Is this n approximately 10, or closer to
1,000,000, or is it even larger? In this paper, we show that it is at most
7,910 by presenting an explicit description of a 7,910-state Turing machine Z
with 1 tape and a 2-symbol alphabet that cannot be proved to run forever in ZFC
(even though it presumably does), assuming ZFC is consistent. The machine is
based on the work of Harvey Friedman on independent statements involving
order-invariant graphs. In doing so, we give the first known upper bound on the
highest provable Busy Beaver number in ZFC. To create Z, we develop and use a
higher-level language, Laconic, which is much more convenient than direct state
manipulation. We also use Laconic to design two Turing machines, G and R, that
halt if and only if there are counterexamples to Goldbach's Conjecture and the
Riemann Hypothesis, respectively.


title:
On the Effects of Measurement Uncertainty in Optimal Control of Contact
  Interactions

abstract:
  Stochastic Optimal Control (SOC) typically considers noise only in the
process model, i.e. unknown disturbances. However, in many robotic applications
involving interaction with the environment, such as locomotion and
manipulation, uncertainty also comes from lack of precise knowledge of the
world, which is not an actual disturbance. We analyze the effects of also
considering noise in the measurement model, by developing a SOC algorithm based
on risk-sensitive control, that includes the dynamics of an observer in such a
way that the control law explicitly depends on the current measurement
uncertainty. In simulation results on a simple 2D manipulator, we have observed
that measurement uncertainty leads to low impedance behaviors, a result in
contrast with the effects of process noise that creates stiff behaviors. This
suggests that taking into account measurement uncertainty could be a
potentially very interesting way to approach problems involving uncertain
contact interactions.


title:
Towards the compression of parton densities through machine learning
  algorithms

abstract:
  One of the most fascinating challenges in the context of parton density
function (PDF) is the determination of the best combined PDF uncertainty from
individual PDF sets. Since 2014 multiple methodologies have been developed to
achieve this goal. In this proceedings we first summarize the strategy adopted
by the PDF4LHC15 recommendation and then, we discuss about a new approach to
Monte Carlo PDF compression based on clustering through machine learning
algorithms.


title:
Cell Associations that Maximize the Average Uplink-Downlink Degrees of
  Freedom

abstract:
  We study the problem of associating mobile terminals to base stations in a
linear interference network, with the goal of maximizing the average rate
achieved over both the uplink and downlink sessions. The cell association
decision is made at a centralized cloud level, with access to global network
topology information. More specifically, given the constraint that each mobile
terminal can be associated to a maximum of N base stations at once, we
characterize the maximum achievable pre-log factor (degrees of freedom) and the
corresponding cell association pattern. Interestingly, the result indicates
that for the case where N > 1, the optimal cell association guarantees the
achievability of the maximum uplink rate even when optimizing for the uplink
alone, and for the case where N=1, the optimal cell association is that of the
downlink. Hence, this work draws attention to the question of characterizing
network topologies for which the problem can be simplified by optimizing only
for the uplink or only for the downlink.


title:
$^{133}$Cs and $^{75}$As NMR investigation of the normal metallic state
  of the quasi-one-dimensional Cs$_2$Cr$_3$As$_3$

abstract:
  We report $^{133}$Cs NMR and $^{75}$As Nuclear Quadrupole Resonance (NQR)
measurements on the normal metallic state above $T_c$ of a
quasi-one-dimensional superconductor Cs$_2$Cr$_3$As$_3$ ($T_c < 1.6$~K). From
the $^{133}$Cs NMR Knight shift $^{133}K$ measured at the Cs1 site, we show
that the uniform spin susceptibility $\chi_{spin}$ increases from 295~K to
$\sim$ 60~K, followed by a mild suppression; $\chi_{spin}$ then levels off
below $\sim$10~K. In contrast, a vanishingly small magnitude of $^{133}K$
indicates that Cs2 sites contribute very little to electrical conduction and
the exchange interactions between 3d electrons at Cr sites. Low frequency Cr
spin dynamics, reflected on $^{75}$As $1/T_1T$ (the nuclear spin-lattice
relaxation rate $1/T_1$ divided by temperature $T$), shows an analogous trend
as $\chi_{spin}$. Comparison with the results of $1/T_1T$ near $T_c$ with
Rb$_2$Cr$_3$As$_3$ ($T_c=6.1$~K) and Rb$_2$Cr$_3$As$_3$ ($T_c=4.8$~K)
establishes a systematic trend that substitution of K$^{+}$ ions with larger
alkali ions progressively suppresses Cr spin fluctuations together with $T_c$.


title: Families of conic K\"ahler-Einstein metrics

abstract:
  Let $p:X\to Y$ be an holomorphic surjective map between compact K\"ahler
manifolds and let $D$ be an effective divisor on $X$ with generically simple
normal crossings support and coefficients in $(0,1)$. Provided that the adjoint
canonical bundle $K_{X_y}+D_y$ of the generic fiber is ample, we show that the
current obtained by glueing the fiberwise conic K\"ahler-Einstein metrics on
the regular locus of the fibration is positive. Moreover, we prove that this
current is bounded outside the divisor and that it extends to a positive
current on $X$.


title:
Effects of long-range hopping and interactions on quantum walk in
  ordered and disordered lattices

abstract:
  We study the effects of long-range hopping and long-range inter-particle
interactions on quantum walk of hard-core bosons in ideal and disordered
one-dimensional lattices. We find that the range of hopping has a much more
significant effect on the particle correlation dynamics than the range of
interactions. We illustrate that long-range hopping makes the correlation
diagrams asymmetric with respect to the sign of the interaction and examine the
relative role of repulsive and attractive interactions on the dynamics of
scattering by isolated impurities and Anderson localization in dis- ordered
lattices. We show that weakly repulsive interactions increase the probability
of tunnelling through isolated impurities and decrease the localization.


title:
Guard Region Model for Pilot Reuse Analysis in Uplink Massive MIMO
  Systems

abstract:
  Massive multiple-input multiple-output (MIMO) are expected to significantly
enhance the spectrum efficiency (SE) and energy efficiency (EE) of future
cellular systems. Since the performance gain of massive MIMO is fundamentally
limited by pilot contamination, pilot reuse design is crucial to achieve
reasonable cell throughput and user rate. In this paper, we leverage stochastic
geometry to model pilot reuse in massive MIMO systems by introducing a guard
region model to match realistic pilot allocation strategies. The uplink
signal-to-interference-plus-noise ratio (SINR) distribution is analytically
derived, based on which the benefits of pilot reuse on cell-throughput and
user-rate are investigated. The optimal pilot reuse factor for uplink
transmission is obtained. We also find through simulations that increasing the
pilot reuse factor beyond a certain value would not improve user-rate, and
could even lead to a significant loss of the cell throughput.


title: Are Most Particles Gravitons?

abstract:
  The number of baryons in the observable universe is of the order of
$10^{80}$, as is the number of electrons. The number of photons is about nine
orders of magnitude greater, $10^{89}$, as is the estimated number of
neutrinos. However, the number of gravitons could be more than twenty orders of
magnitude larger yet, of the order of $10^{113} r$, where $r$ is the
tensor-to-scalar ratio for quantum fluctuations produced by inflation, which
could be as high as $0.1$.


title:
A countdown process, with application to the rank of random matrices
  over $\mathbb F_q(n)$

abstract:
  Motivated by the work of Fulman and Goldstein, comparing the distribution of
the corank of random matrices in $\mathbb F_q[n]$ with the limit distribution
as $n \to \infty$, we define a countdown process, driven by independent
geometric random variables related to random integer partitions. Analysis of
this process leads to sharper bounds on the total variation distance.


title:
Locally Restricted Sequential Structures and Runs of a Subcomposition in
  Integer Compositions

abstract:
  We study part sizes of supercritical locally restricted sequential
structures. This extends previous results about locally restricted integer
compositions and part sizes in smooth supercritical compositional structures.
Applications are given for runs of subcompositions. The problems are formulated
as enumerating directed walks in sized infinite digraphs and the proofs depend
heavily on earlier results by Bender and Canfield about infinite transfer
matrices.


title: Tamm's surface states and Bose-Einstein condensation

abstract:
  We calculate and discuss the effects on the thermodynamic properties of a 3D
Bose gas caused by a gap $\Delta$ in the energy of the particles constituting
the gas that without the gap behaves like an ideal Bose gas. Explicit formulae
with arbitrary $\Delta$ values are discussed for: the critical temperature
which increases as the gap grows; the condensate fraction; the internal energy;
and the constant-volume specific heat found to possess a jump-discontinuity for
any $\Delta$ different from zero. Three dimensional infinite ideal Bose gas
results are recovered when we the energy gap goes to zero.


title: Dirichlet spectrum and Green function

abstract:
  In the first part of this article we obtain an identity relating the radial
spectrum of rotationally invariant geodesic balls and an isoperimetric quotient
$\sum 1/\lambda_{i}^{\rm rad}=\int V(s)/S(s)ds$. We also obtain upper and lower
estimates for the series $\sum \lambda_{i}^{-2}(\Omega)$ where $\Omega$ is an
extrinsic ball of a proper minimal surface of $\mathbb{R}^{3}$. In the second
part we show that the first eigenvalue of bounded domains is given by iteration
of the Green operator and taking the limit, $\lambda_{1}(\Omega)=\lim_{k\to
\infty} \Vert G^k(f)\Vert_{2}/\Vert G^{k+1}(f)\Vert_{2}$ for any function
$f>0$. In the third part we obtain explicitly the $L^{1}(\Omega, \mu)$-momentum
spectrum of a bounded domain $\Omega$ in terms of its Green operator. In
particular, we obtain the first eigenvalue of a weighted bounded domain in
terms of the $L^{1}(\Omega, \mu)$-momentum spectrum, extending the work of
Hurtado-Markvorsen-Palmer on the first eigenvalue of rotationally invariant
balls.


title: A closer look at the cosmological implications of the $\Lambda$HDE model

abstract:
  In a previous paper, we proposed a heterotic dark energy model, called
$\Lambda$HDE, in which dark energy is composed of two components: cosmological
constant (CC) and holographic dark energy (HDE). The aim of this work is to
give a more comprehensive and systematic investigation on the cosmological
implications of the $\Lambda$HDE model. Firstly, we make use of the current
observations to constrain the $\Lambda$HDE model, and compare its cosmology-fit
results with the results of the $\Lambda$CDM and the HDE model. Then, by
combining a qualitative theoretical analysis with a quantitative numerical
study, we discuss the impact of considering curvature on the cosmic evolutions
of fractional HDE density $\Omega_{hde}$ and fractional CC density
$\Omega_{\Lambda}$, as well as on the ultimate cosmic fate. Finally, we explore
the effects of adopting different types of observational data. We find that:
(1) the current observational data cannot distinguish the $\Lambda$HDE model
from the $\Lambda$CDM and the HDE model; this indicates that DE may contain
multiple components. (2) the asymptotic solution of $\Omega_{hde}$ and the
corresponding cosmic fate in a flat universe can be extended to the case of a
non-flat universe; moreover, compared with the case of a flat universe,
considering curvature will make HDE closer to a phantom dark energy. (3)
compared with JLA dataset, SNLS3 data more favor a phantom type HDE; in
contrast, using other types of observational data have no significant impact on
the cosmic evolutions of the $\Lambda$HDE model.


title:
The Rise of the First Stars: Supersonic Streaming, Radiative Feedback,
  and 21-cm Cosmology

abstract:
  Understanding the formation and evolution of the first stars and galaxies
represents one of the most exciting frontiers in astronomy. Since the universe
was filled with hydrogen atoms at early times, the most promising probe of the
epoch of the first stars is the prominent 21-cm spectral line of hydrogen.
Current observational efforts are focused on the cosmic reionization era, but
observations of the pre-reionization cosmic dawn are also promising. While
observationally unexplored, theoretical studies predict a rich variety of
observational signatures from cosmic dawn. As the first stars formed, their
radiation (plus that from stellar remnants) produced significant cosmic events
including Lyman-alpha coupling at z~25, and early X-ray heating. Much focus has
gone to studying the angle-averaged power spectrum of 21-cm fluctuations.
Additional probes include the global (sky-averaged) 21-cm spectrum, and the
line-of-sight anisotropy of the 21-cm power spectrum. A particularly striking
signature may result from the recently recognized effect of a supersonic
relative velocity between the dark matter and gas. Work in this field, focused
on understanding the whole era of reionization and cosmic dawn with analytical
models and numerical simulations, is likely to grow in intensity and
importance, as the theoretical predictions are finally expected to confront
21-cm observations in the coming years. [Abridged]


title:
Minimax Rate-optimal Estimation of High-dimensional Covariance Matrices
  with Incomplete Data

abstract:
  Missing data occur frequently in a wide range of applications. In this paper,
we consider estimation of high-dimensional covariance matrices in the presence
of missing observations under a general missing completely at random model in
the sense that the missingness is not dependent on the values of the data.
Based on incomplete data, estimators for bandable and sparse covariance
matrices are proposed and their theoretical and numerical properties are
investigated.
  Minimax rates of convergence are established under the spectral norm loss and
the proposed estimators are shown to be rate-optimal under mild regularity
conditions. Simulation studies demonstrate that the estimators perform well
numerically. The methods are also illustrated through an application to data
from four ovarian cancer studies. The key technical tools developed in this
paper are of independent interest and potentially useful for a range of related
problems in high-dimensional statistical inference with missing data.


title: Occurrence Statistics of Entities, Relations and Types on the Web

abstract:
  The problem of collecting reliable estimates of occurrence of entities on the
open web forms the premise for this report. The models learned for tagging
entities cannot be expected to perform well when deployed on the web. This is
owing to the severe mismatch in the distributions of such entities on the web
and in the relatively diminutive training data. In this report, we build up the
case for maximum mean discrepancy for estimation of occurrence statistics of
entities on the web, taking a review of named entity disambiguation techniques
and related concepts along the way.


title: Variational Inference with Agent-Based Models

abstract:
  In this paper, we develop a variational method to track and make predictions
about a real-world system from continuous imperfect observations about this
system, using an agent-based model that describes the system dynamics. By
combining the power of big data with the power of model-thinking in the
stochastic process framework, we can make many valuable predictions. We show
how to track the spread of an epidemic at the individual level and how to make
short-term predictions about traffic congestion. This method points to a new
way to bring together modelers and data miners by turning the real world into a
living lab.


title: Observable Effects of Quantum Gravity

abstract:
  We discuss the generic phenomenology of quantum gravity and, in particular,
argue that the observable effects of quantum gravity, associated with new,
extended, non-local, non-particle-like quanta, and accompanied by a dynamical
energy-momentum space, are not necessarily Planckian and that they could be
observed at much lower and experimentally accessible energy scales.


title:
Classification of Multidimensional Darboux Transformations: First Order
  and Continued Type

abstract:
  We analyze Darboux transformations in very general settings for
multidimensional linear partial differential operators. We consider all known
types of Darboux transformations, and present a new type. We obtain a full
classification of all operators that admit Wronskian type Darboux
transformations of first order and a complete description of all possible
first-order Darboux transformations. We introduce a large class of invertible
Darboux transformations of higher order, which we call Darboux transformations
of continued Type I. This generalizes the class of Darboux transformations of
Type I, which was previously introduced. There is also a modification of this
type of Darboux transformations, continued Wronskian type, which generalize
Wronskian type Darboux transformations.


title: Universal One-dimensional Atomic Gases Near Odd-wave Resonance

abstract:
  We show the renormalization of contact interaction for odd-wave scattering in
one-dimension(1D). Based on the renormalized interaction, we exactly solve the
two-body problem in a harmonic trap, and further explore the universal
properties of spin-polarized fermions near odd-wave resonance using the
operator product expansion method. It is found that the high-momentum
distribution behaves as $C/k^2$, with $C$ the odd-wave contact. Various
universal relations are derived. Our work suggests a new universal system
emergent in 1D with large odd-wave scattering length.


title:
Interior Penalty Discontinuous Galerkin Methods for Second Order Linear
  Non-Divergence Form Elliptic PDEs

abstract:
  This paper develops interior penalty discontinuous Galerkin (IP-DG) methods
to approximate $W^{2,p}$ strong solutions of second order linear elliptic
partial differential equations (PDEs) in non-divergence form with continuous
coefficients. The proposed IP-DG methods are closely related to the IP-DG
methods for advection-diffusion equations, and they are easy to implement on
existing standard IP-DG software platforms. It is proved that the proposed
IP-DG methods have unique solutions and converge with optimal rate to the
$W^{2,p}$ strong solution in a discrete $W^{2,p}$-norm. The crux of the
analysis is to establish a DG discrete counterpart of the Calderon-Zygmund
estimate and to adapt a freezing coefficient technique used for the PDE
analysis at the discrete level. As a byproduct of our analysis, we also
establish broken $W^{1,p}$-norm error estimates for IP-DG approximations of
constant coefficient elliptic PDEs. Numerical experiments are provided to gauge
the performance of the proposed IP-DG methods and to validate the theoretical
convergence results.


title: Cartan Connections on Lie Groupoids and their Integrability

abstract:
  A multiplicatively closed, horizontal $n$-plane field $D$ on a Lie groupoid
$G$ over $M$ generalizes to intransitive geometry the classical notion of a
Cartan connection. The infinitesimalization of the connection $D$ is a Cartan
connection $\nabla $ on the Lie algebroid of $G$, a notion already studied
elsewhere by the author. It is shown that $\nabla $ may be regarded as
infinitesimal parallel translation in the groupoid $G$ along $D$. From this
follows a proof that $D$ defines a pseudoaction generating a pseudogroup of
transformations on $M$ precisely when the curvature of $\nabla $ vanishes. A
byproduct of this analysis is a detailed description of multiplication in the
groupoid $J^1 G$ of one-jets of bisections of $G$.


title:
Observation of orbital two-channel Kondo effect in a ferromagnetic
  L10-MnGa film

abstract:
  The experimental existence and stability of the quantum criticality point of
the two-channel Kondo (2CK) effect displaying exotic non-Fermi liquid physics
has been buried in persistent confusion despite the intensive theoretical and
experimental efforts in past three decades. Here we report an experimental
realization of the two-level system scattering-induced orbital 2CK effect in a
ferromagnetic L10-MnGa film, which is signified by a magnetic field-independent
resistivity upturn that has a logarithmic and square-root temperature
dependence beyond and below the Kondo temperature of ~14.5 K, respectively. Our
result not only evidences the robust existence of orbital 2CK effect even in
the presence of strong magnetic fields and long-range ferromagnetic ordering
but also extends the scope of 2CK host materials from nonmagnetic nanoscale
point contacts to diffusive conductors of disordered alloys.


title: Extension of ATLAST/LUVOIR's Capabilities to 5 Microns, or Beyond

abstract:
  ATLAST is a particular realization of LUVOIR, the Large Ultraviolet Optical
Infrared telescope, a ~10 m diameter space telescope being defined for
consideration in the 2020 Decadal Review of astronomy and astrophysics.
ATLAST/LUVOIR is generally thought of as an ambient temperature (~300 K)
system, and little consideration has been given to using it at infrared
wavelengths longward of ~2 {\mu}m. We assess the scientific and technical
benefits of operating such a telescope further into the infrared, with
particular emphasis on the study of exoplanets, which is a major science theme
for ATLAST/LUVOIR. For the study of exoplanet atmospheres, the capability to
work at least out to 5.0 {\mu}m is highly desirable. Such an extension of the
long wavelength limit of ATLAST would greatly increase its capabilities for
studies of exoplanet atmospheres and provide powerful capabilities for the
study of a wide range of astrophysical questions. We present a concept for a
fiber-fed grating spectrometer which would enable R = 200 spectroscopy on
ATLAST with minimal impact on the other focal planet instruments. We conclude
that it is technically feasible and highly desirable scientifically to extend
the wavelength range of ATLAST to at least 5 {\mu}m.


title:
Decentralized Autonomous Navigation Strategies for Multi-Robot Search
  and Rescue

abstract:
  In this report, we try to improve the performance of existing approaches for
search operations in multi-robot context. We propose three novel algorithms
that are using a triangular grid pattern, i.e., robots certainly go through the
vertices of a triangular grid during the search procedure. The main advantage
of using a triangular grid pattern is that it is asymptotically optimal in
terms of the minimum number of robots required for the complete coverage of an
arbitrary bounded area. We use a new topological map which is made and shared
by robots during the search operation. We consider an area that is unknown to
the robots a priori with an arbitrary shape, containing some obstacles. Unlike
many current heuristic algorithms, we give mathematically proofs of convergence
of the algorithms. The computer simulation results for the proposed algorithms
are presented using a simulator of real robots and environment. We evaluate the
performance of the algorithms via experiments with real robots. We compare the
performance of our own algorithms with three existing algorithms from other
researchers. The results demonstrate the merits of our proposed solution. A
further study on formation building with obstacle avoidance for a team of
mobile robots is presented in this report. We propose a decentralized formation
building with obstacle avoidance algorithm for a group of mobile robots to move
in a defined geometric configuration. Furthermore, we consider a more
complicated formation problem with a group of anonymous robots; these robots
are not aware of their position in the final configuration and need to reach a
consensus during the formation process. We propose a randomized algorithm for
the anonymous robots that achieves the convergence to a desired configuration
with probability 1. We also propose a novel obstacle avoidance rule, used in
the formation building algorithm.


title: Neural Dataset Generality

abstract:
  Often the filters learned by Convolutional Neural Networks (CNNs) from
different datasets appear similar. This is prominent in the first few layers.
This similarity of filters is being exploited for the purposes of transfer
learning and some studies have been made to analyse such transferability of
features. This is also being used as an initialization technique for different
tasks in the same dataset or for the same task in similar datasets.
Off-the-shelf CNN features have capitalized on this idea to promote their
networks as best transferable and most general and are used in a cavalier
manner in day-to-day computer vision tasks.
  It is curious that while the filters learned by these CNNs are related to the
atomic structures of the images from which they are learnt, all datasets learn
similar looking low-level filters. With the understanding that a dataset that
contains many such atomic structures learn general filters and are therefore
useful to initialize other networks with, we propose a way to analyse and
quantify generality among datasets from their accuracies on transferred
filters. We applied this metric on several popular character recognition,
natural image and a medical image dataset, and arrived at some interesting
conclusions. On further experimentation we also discovered that particular
classes in a dataset themselves are more general than others.


title:
A method of non-linear state feedback controller design based on state
  prediction

abstract:
  In this paper, we considered a design method of non-linear state feedback
controller for input-affine non-linear system taking data losses into account.
When data is lost in control system, control input is fixed to constant value
or to the last implemented value [1,2]. When data losses are taken into
account, these methods do not guarantee the stability of desired closed-loop.
The proposed method guarantees the stability and robustness properties in the
presence of uncertainty and data losses.


title: Reflection principles for class groups

abstract:
  We present several new examples of reflection principles which apply to both
class groups of number fields and picard groups of of curves over
$\mathbb{P}^{1}/\mathbb{F}_{p}$. This proves a conjecture of Lemmermeyer about
equality of 2-rank in subfields of $A_{4}$, up to a constant not depending on
the discriminant in the number field case, and exactly in the function field
case. More generally we prove similar relations for subfields of a Galois
extension with group $G$ for the cases when $G$ is $S_{3}$, $S_{4}$, $A_{4}$,
$D_{2l}$ and $\mathbb{Z}/l\mathbb{Z}\rtimes\mathbb{Z}/r\mathbb{Z}$. The method
of proof uses sheaf cohomology on 1-dimensional schemes, which reduces to
Galois module computations.


title: Betti numbers in three dimensional minimal model program

abstract:
  Let $X$ be a smooth projective threefold. We prove that, among the process of
minimal model program, the variance of the third Betti number can be bounded by
some integer depends only on the Picard number of $X$.


title:
Entanglement of spin-1/2 Heisenberg Antiferromagnetic quantum spin
  chains

abstract:
  The quantum entanglement measure is determined, for the first time, for a
collection of spin-1/2 arranged in a infinite chain with finite temperature and
applied to a single-crystal \beta-\mathrm{T_eVO_4}. The physical quantity
proposed here to measure the entanglement is the distance between states by
adopting the Hilbert-Schmidt norm. We relate the distance between states with
the magnetic susceptibility. The decoherence temperature, above which the
entanglement is suppressed, is determined for a system. A correlation among
their decoherence temperatures and their respective exchange coupling constants
is established, moreover, it is conjectured that the exchange coupling protects
the system from decoherence as temperature increases.


title: Online learning for Social Spammer Detection on Twitter

abstract:
  Social networking services like Twitter have been playing an import role in
people's daily life since it supports new ways of communicating effectively and
sharing information. The advantages of these social network services enable
them rapidly growing. However, the rise of social network services is leading
to the increase of unwanted, disruptive information from spammers, malware
discriminators, and other content polluters. Negative effects of social
spammers do not only annoy users, but also lead to financial loss and privacy
issues. There are two main challenges of spammer detection on Twitter. Firstly,
the data of social network scale with a huge volume of streaming social data.
Secondly, spammers continually change their spamming strategy such as changing
content patterns or trying to gain social influence, disguise themselves as far
as possible. With those challenges, it is hard to directly apply traditional
batch learning methods to quickly adapt newly spamming pattern in the
high-volume and real-time social media data. We need an anti-spammer system to
be able to adjust the learning model when getting a label feedback. Moreover,
the data on social media may be unbounded. Then, the system must allow update
efficiency model in both computation and memory requirements. Online learning
is an ideal solution for this problem. These methods incrementally adapt the
learning model with every single feedback and adjust to the changing patterns
of spammers overtime. Our experiments demonstrate that an anti-spam system
based on online learning approach is efficient in fast changing of spammers
comparing with batch learning methods. We also attempt to find the optimal
online learning method and study the effectiveness of various feature sets on
these online learning methods.


title:
A wavelet-based Projector Augmented-Wave (PAW) method: reaching
  frozen-core all-electron precision with a systematic, adaptive and localized
  wavelet basis set

abstract:
  We present a Projector Augmented-Wave~(PAW) method based on a wavelet basis
set. We implemented our wavelet-PAW method as a PAW library in the ABINIT
package [http://www.abinit.org] and into BigDFT [http://www.bigdft.org]. We
test our implementation in prototypical systems to illustrate the potential
usage of our code. By using the wavelet-PAW method, we can simulate charged and
special boundary condition systems with frozen-core all-electron precision.
Furthermore, our work paves the way to large-scale and potentially order-N
simulations within a PAW method.


title: ABC implies a Zsigmondy principle for ramification

abstract:
  Let $K$ be a number field or a function field of characteristic 0. If $K$ is
a number field, assume the $abc$-conjecture for $K$. We prove a variant of
Zsigmondy's theorem for ramified primes in preimage fields of rational
functions in $K(x)$ that are not postcritically finite. For example, suppose
$K$ is a number field and $f\in K[x]$ is not postcritically finite, and let
$K_n$ be the field generated by the $n$th iterated preimages under $f$ of
$\beta\in K$. We show that for all large $n$, there is a prime of $K$ that
ramifies in $K_n$ and does not ramify in $K_m$ for any $m<n$.


title:
Highly anisotropic electronic transport properties of monolayer and
  bilayer phosphorene from first principles

abstract:
  The intrinsic carrier transport dynamics in phosphorene is theoretically
examined. Utilizing a density functional theory treatment, the low-field
mobility and the saturation velocity are characterized for both electrons and
holes in the monolayer and bilayer structures. The analysis clearly elucidates
the crystal orientation dependence manifested through the anisotropic band
structure and the carrier-phonon scattering rates. In the monolayer, the hole
mobility in the armchair direction is estimated to be approximately five times
larger than in the zigzag direction at room temperature (460 cm$^2$/Vs vs. 90
cm$^2$/Vs). The bilayer transport, on the other hand, exhibits a more modest
anisotropy with substantially higher mobilities (1610 cm$^2$/Vs and 760
cm$^2$/Vs, respectively). The calculations on the conduction-band electrons
indicate a comparable dependence while the characteristic values are generally
smaller by about a factor of two. The variation in the saturation velocity is
found to be less pronounced. With the anticipated superior performance and the
diminished anisotropy, few-layer phosphorene offers a promising opportunity
particularly in p-type applications.


title:
What really happens in strongly correlated superconductors: Insights
  from a quantum Monte-Carlo study of high temperature superconductivity in
  FeSe films

abstract:
  This is a "perspective" inspired by the forthcoming article, "What makes the
$T_c$ of monolayer FeSe on SrTiO so high: a sign-problem free quantum Monte
Carlo study," by Z-X. Li, F. Wang, H. Yao, and D-H. Lee, arXiv:1512.06179.


title: Frequency Assignment Problem with Net Filter Discrimination Constraints

abstract:
  Managing radio spectrum resources is a crucial issue. The frequency
assignment problem (FAP) basically aims to allocate, in an efficient manner,
limited number of frequencies to communication links. Geographically close
links, however, cause interference, which complicates the assignment, imposing
frequency separation constraints. The FAP is closely related to the
graph-coloring problem and it is an NP-hard problem. In this paper, we propose
to incorporate the randomization into greedy and fast heuristics. As far as
being implemented, the proposed algorithms are very straight forward and are
without system parameters that need tuned. The proposed algorithms
significantly improve, quickly and effectively, the solutions obtained by
greedy algorithms in terms of the number of assigned frequencies and the range.
The enhanced versions of proposed algorithms perform close to the lower bounds
while running for a reasonable duration. Another novelty of our study is its
consideration of the net filter discrimination effects in the communication
model. Performance analysis is done by synthetic and measured data, where the
measurement data includes the effect of the real 3-dimensional (3D)
geographical features in the Daejeon region in Korea. In both cases, we observe
a significant improvement by employing randomized heuristics.


title: Sparsity-Based Error Detection in DC Power Flow State Estimation

abstract:
  This paper presents a new approach for identifying the measurement error in
the DC power flow state estimation problem. The proposed algorithm exploits the
singularity of the impedance matrix and the sparsity of the error vector by
posing the DC power flow problem as a sparse vector recovery problem that
leverages the structure of the power system and uses $l_1$-norm minimization
for state estimation. This approach can provably compute the measurement errors
exactly, and its performance is robust to the arbitrary magnitudes of the
measurement errors. Hence, the proposed approach can detect the noisy elements
if the measurements are contaminated with additive white Gaussian noise plus
sparse noise with large magnitude. The effectiveness of the proposed
sparsity-based decomposition-DC power flow approach is demonstrated on the IEEE
118-bus and 300-bus test systems.


title: Finalizing tentative matches from truncated preference lists

abstract:
  Consider the standard hospitals/residents problem, or the two-sided
many-to-one stable matching problem, and assume that the true preference lists
of both sides are complete and strict. The lists actually submitted, however,
are truncated. Let I be such a truncated instance. When we apply the
resident-proposing deferred acceptance algorithm of Gale and Shapley to I, the
algorithm produces a set of tentative matches (resident-hospital pairs). We say
that a tentative match in this set is finalizable in I if it is in the
resident-optimal stable matching for every completion of I (a complete instance
of which I is a truncation). We study the problem we call FTM (Finalizability
of Tentative Matches) of deciding if a given tentative match is finalizable in
a given truncated instance. We first show that FTM is coNP-complete, even in
the stable marriage case where the quota of each hospital is restricted to be
1.
  We then introduce and study a special case: we say that a truncated instance
is resident-minimal, if further truncation of the preference lists of the
residents inevitably changes the set of tentative matches. Resident-minimal
instances are not only practically motivated but also useful in natural
backtrack computations for the general case. We give a computationally useful
characterization of negative instances of FTM in this special case, which, for
instance, can be used to formulate an integer program for FTM. For the stable
marriage case, in particular, this characterization yields a polynomial time
algorithm to solve FTM for resident-minimal instances. On the other hand, we
show that FTM remains coNP-complete for resident-minimal instances, if the
maximum quota of the hospitals is 2 or larger.
  We also give a polynomial-time decidable sufficient condition for a tentative
match to be finalizable in the general case.


title: The mixed-phase version of moist-air entropy

abstract:
  The aim of this note is to derive the mixed-phase version of the moist-air
entropy potential temperature $\theta_s$ derived in Marquet (2011).
  This mixed-phase version is suitable to describe parcels where liquid water
and ice are allowed to coexist, with possible under- or super-saturations, with
possible supercooled water and with possible different temperatures for dry air
and water vapour, on the one hand, condensed water and ice, on the other hand.
  The impact of this new mixed-phase version for $\theta_s$ are evaluated by
using high latitudes, SHEBA/FIRE-ACE vertical profiles depicted in Figure 7 of
Morisson et al. (2011).


title:
First-principle study on compensated half metallic double perovskite
  compound $Ba_2PrVO_6$

abstract:
  The first-principle study on double perovskite compound Ba$_2$PrVO$_6$ has
been presented in this paper. By analysing band structures and integrated
density of states, it is found that Ba$_2$PrVO$_6$ is ferromagnetic metallic
within LSDA and compensated half metallic whithin LSDA+U. According to the
total and partial density of states, the anti-ferromagnetism of Ba$_2$PrVO$_6$
is originated from the spin down state Pr$^{4+}$ ($4f_{-2}$) and the spin up
hybridized state between the partially filled $t_{2g}$ state of V and the
partially filled triple-degeneration state $4f_{-1}$, $4f_{+1}$, $4f_{+3}$ of
Pr. We have investigated the magnetic evaluation of Ba$_2$PrVO$_6$ through
fixed spin moment calculations, and the results indicate that the compensated
half-metallic state is the ground state. The thermodynamic properties of
Ba$_2$PrVO$_6$ are also studied by employing the quasi-harmonic Debye model.


title:
Spectral analysis of the Navier-Stokes equations using the combination
  matrix

abstract:
  This work is a continuation of the analysis first presented in Cheung & Zaki
(2014). In that study, the combination matrix was introduced as a means to
tractably handle the nonlinear terms in the spectral domain. In this work, a
different approach is discussed. Rather than analyze solutions to the energy
equation, we examine the forced Navier-Stokes equations in spectral space and
determine if direct solutions to the momentum equations can be found. This is
done by using the combination matrix to rewrite the Navier-Stokes as a system
of intersecting quadratic polynomials. Intrepreted geometrically, any solution
to the Navier-Stokes can be represented as a the intersection of a multiple
conic sections.


title: Knight--Walras Equilibria

abstract:
  Knightian uncertainty leads naturally to nonlinear expectations. We introduce
a corresponding equilibrium concept with sublinear prices and establish their
existence. In general, such equilibria lead to Pareto inefficiency and coincide
with Arrow--Debreu equilibria only if the values of net trades are
ambiguity--free in the mean. Without aggregate uncertainty, inefficiencies
arise generically.
  We introduce a constrained efficiency concept, uncertainty--neutral
efficiency and show that Knight--Walras equilibrium allocations are efficient
in this constrained sense. Arrow--Debreu equilibria turn out to be non--robust
with respect to the introduction of Knightian uncertainty.


title:
The frequency and properties of young tidal dwarf galaxies in nearby
  gas-rich groups

abstract:
  We present high-resolution Giant Metrewave Radio Telescope (GMRT) HI
observations and deep Canada-France-Hawaii Telescope (CFHT) optical imaging of
two galaxy groups: NGC 4725/47 and NGC 3166/9. These data are part of a
multi-wavelength unbiased survey of the gas-rich dwarf galaxy populations in
three nearby interacting galaxy groups. The NGC 4725/47 group hosts two tidal
knots and one dIrr. Both tidal knots are located within a prominent HI tidal
tail, appear to have sufficient mass (M_gas~10^8 M_sol) to evolve into
long-lived tidal dwarf galaxies (TDGs) and are fairly young in age. The NGC
3166/9 group contains a TDG candidate, AGC 208457, at least three dIrrs and
four HI knots. Deep CFHT imaging confirms that the optical component of AGC
208457 is bluer -- with a 0.28 mag g-r colour -- and a few Gyr younger than its
purported parent galaxies. Combining the results for these groups with those
from the NGC 871/6/7 group reported earlier, we find that the HI properties,
estimated stellar ages and baryonic content of the gas-rich dwarfs clearly
distinguish tidal features from their classical counterparts. We optimistically
identify four potentially long-lived tidal objects associated to three separate
pairs of interacting galaxies, implying that TDGs are not readily produced
during interaction events as suggested by some recent simulations. The tidal
objects examined in this survey also appear to have a wider variety of
properties than TDGs of similar mass formed in current simulations of
interacting galaxies, which could be the result of pre- or post-formation
environmental influences.


title: On Asymptotically Orthonormal Sequences

abstract:
  An asymptotically orthonormal sequence is a sequence which is 'nearly'
orthonormal in the sense that it satisfies the Parseval equality up to two
constants close to one. In this paper, we explore such sequences formed by
normalized reproducing kernels of model spaces and de Branges Rovnyak spaces.


title:
Sharp mean-square regularity results for SPDEs with fractional noise and
  optimal convergence rates for the numerical approximations

abstract:
  This article offers sharp spatial and temporal mean-square regularity results
for a class of semi-linear parabolic stochastic partial differential equations
(SPDEs) driven by infinite dimensional fractional Brownian motion with the
Hurst parameter greater than one-half. In addition, mean-square numerical
approximation of such problem are investigated, performed by the spectral
Galerkin method in space and the linear implicit Euler method in time. The
obtained sharp regularity properties of the problems enable us to identify
optimal mean-square convergence rates of the full discrete scheme. These
theoretical findings are accompanied by several numerical examples.


title: New face-centered photonic square lattices with flat bands

abstract:
  We report two new classes of face-centered photonic square lattices with flat
bands which we call the Lieb-I and the Lieb-II lattices. There are 5 and 7
sites in the corresponding unit cells of the simplest Lieb-I and Lieb-II
lattices, respectively. The number of flat bands $m$ in the new Lieb lattices
is related to the number of sites $N$ in the unit cell by $m=(N-1)/2$. Physical
properties of the lattices with even and odd number of flat bands are
different. We also consider localization of light in such Lieb lattices. If the
input beam excites the flat-band mode, it will not diffract during propagation,
owing to the strong localization in the flat-band mode. For the Lieb-II
lattice, we also find that the beam will oscillate and still not diffract
during propagation, because of the intrinsic oscillating properties of certain
flat-band modes. The period of oscillation is determined by the energy
difference between the two flat bands. This study provides a new platform for
the investigation of flat-band modes.


title: Phonon transport in single-layer Boron nanoribbons

abstract:
  Inspired by the successful synthesis of several allotropes, boron sheets have
been one of the hottest spot areas of focus in various fields. Here, we study
phonon transport in three types of boron nanoribbons with zigzag and armchair
edges by using a non-equilibrium Green's function combined with first
principles methods. Diverse transport properties are found in the nanoribbons.
At the room temperature, their highest thermal conductance can be comparable
with that of graphene, while the lowest thermal conductance is less than half
of graphene's. The three boron sheets exhibit different anisotropic transport
characteristics. Two of these sheets have stronger phonon transport abilities
along the zigzag edges than the armchair edges, while in the case of the third,
the results are reversed. With the analysis of phonon dispersion, bonding
charge density, and simplified models of atomic chains, the mechanisms of the
diverse phonon properties are discussed. Because all boron allotropes consists
of hexagonal and triangular rings, many hybrid patterns can be constructed
naturally without doping, adsorption, and defects. Our results are useful in
materials and devices design using boron sheets for thermal management.


title:
Bayesian Lower Bounds for Dense or Sparse (Outlier) Noise in the RMT
  Framework

abstract:
  Robust estimation is an important and timely research subject. In this paper,
we investigate performance lower bounds on the mean-square-error (MSE) of any
estimator for the Bayesian linear model, corrupted by a noise distributed
according to an i.i.d. Student's t-distribution. This class of prior
parametrized by its degree of freedom is relevant to modelize either dense or
sparse (accounting for outliers) noise. Using the hierarchical Normal-Gamma
representation of the Student's t-distribution, the Van Trees' Bayesian
Cram\'er-Rao bound (BCRB) on the amplitude parameters is derived. Furthermore,
the random matrix theory (RMT) framework is assumed, i.e., the number of
measurements and the number of unknown parameters grow jointly to infinity with
an asymptotic finite ratio. Using some powerful results from the RMT,
closed-form expressions of the BCRB are derived and studied. Finally, we
propose a framework to fairly compare two models corrupted by noises with
different degrees of freedom for a fixed common target signal-to-noise ratio
(SNR). In particular, we focus our effort on the comparison of the BCRBs
associated with two models corrupted by a sparse noise promoting outliers and a
dense (Gaussian) noise, respectively.


title:
The damped oscillating propagation of the compensating self-accelerating
  beams

abstract:
  We report a new form of compensating accelerating beam generated by amplitude
modulation of the symmetric Airy beam (SAB) caustics with an exponential
apodization mask. Our numerical study manifests that the compensating beam is
with one main-lobe beam structure and can maintain the mean-intensity invariant
both in the free space and loss media. Specially, the beam inherits the
beamlets structure from the SAB and owns a novel damped oscillating propagation
property. We also conduct a comparative study of its propagation property with
that of the Airy beam theoretically. And by altering the signs of 2D masks, the
main lobe of the compensating beam can be modulated to orientate in four
different quadrants flexibly. The proposed compensating accelerating beam is
anticipated to get special applications in particle manipulation or plasmas
regions.


title: Path following control for a reversing general 2-trailer system

abstract:
  In order to meet the requirements for autonomous systems in real world
applications, reliable path following controllers have to be designed to
execute planned paths despite the existence of disturbances and model errors.
In this paper we propose a Linear Quadratic controller for stabilizing a
2-trailer system with possible off-axle hitching around preplanned paths in
backward motion. The controller design is based on a kinematic model of a
general 2-trailer system including the possibility for off-axle hitching.
Closed-loop stability is proved around a set of paths, typically chosen to
represent the possible output from the path planner, using theory from linear
differential inclusions. Using convex optimization tools a single quadratic
Lyapunov function is computed for the entire set of paths.


title: Cheeger isoperimetric constant of Gromov hyperbolic manifolds and graphs

abstract:
  In this paper we study the relationship of hyperbolicity and (Cheeger)
isoperimetric inequality in the context of Riemannian manifolds and graphs. We
characterize the hyperbolic manifolds and graphs (with bounded local geometry)
verifying this isoperimetric inequality, in terms of their Gromov boundary.
Furthermore, we characterize the trees with isoperimetric inequality (without
any hypothesis). As an application of our results, we obtain the solvability of
the Dirichlet problem at infinity for these Riemannian manifolds and graphs,
and that the Martin boundary is homeomorphic to the Gromov boundary.


title:
Phase transitions in ensembles of solitons induced by an optical pumping
  or a strong electric field

abstract:
  The latest trend in studies of modern electronically and/or optically active
materials is to provoke phase transformations induced by high electric fields
or by short (femtosecond) powerful optical pulses. The systems of choice are
cooperative electronic states whose broken symmetries give rise to topological
defects. For typical quasi-one-dimensional architectures, those are the
microscopic solitons taking from electrons the major roles as carriers of
charge or spin. Because of the long-range ordering, the solitons experience
unusual super-long-range forces leading to a sequence of phase transitions in
their ensembles: the higher-temperature transition of the confinement and the
lower one of aggregation into macroscopic walls. Here we present results of an
extensive numerical modeling for ensembles of both neutral and charged solitons
in both two- and three-dimensional systems. We suggest a specific Monte Carlo
algorithm preserving the number of solitons, which substantially facilitates
the calculations, allows to extend them to the three-dimensional case and to
include the important long-range Coulomb interactions. The results confirm the
first confinement transition, except for a very strong Coulomb repulsion, and
demonstrate a pattern formation at the second transition of aggregation.


title: Superconductivity and Ferromagnetism in Hole-Doped RbEuFe$_4$As$_4$

abstract:
  We discover a robust coexistence of superconductivity and ferromagnetism in
an iron arsenide RbEuFe$_4$As$_4$. The new material crystallizes in an
intergrowth structure of RbFe$_2$As$_2$ and EuFe$_2$As$_2$, such that the Eu
sublattice turns out to be primitive instead of being body-centered in
EuFe$_2$As$_2$. The FeAs layers, featured by asymmetric As coordinations, are
hole doped due to charge homogenization. Our combined measurements of
electrical transport, magnetization and heat capacity unambiguously and
consistently indicate bulk superconductivity at 36.5 K in the FeAs layers and
ferromagnetism at 15 K in the Eu sublattice. Interestingly, the Eu-spin
ferromagnetic ordering belongs to a rare third-order transition, according to
the Ehrenfest classification of phase transition. We also identify an
additional anomaly at $\sim$ 5 K, which is possibly associated with the
interplay between superconductivity and ferromagnetism.


title: Comments on the Green's function of a planar domain

abstract:
  We study several quantities associated to the Green's function of a multiply
connected domain in the complex plane. Among them are some intrinsic properties
such as geodesics, curvature, and $L^2$-cohomology of the capacity metric and
critical points of the Green's function. The principal idea used is an affine
scaling of the domain that furnishes quantitative boundary behaviour of the
Green's function and related objects.


title:
The laws of Newton and Coulomb as information transmission by virtual
  particles

abstract:
  In elementary particle physics the philosophy of virtual particles is widely
used. We use this philosophy to obtain the famous inverse square law of
classical physics. We define a formal model without fields or forces, but with
virtual particle - information transmitter. This formal model admits very
simple (school level) interpretation with two classical particles and one
virtual. Then we prove (in a mathematically rigorous way) that the trajectories
in our model converge to standard Newtonian trajectories of classical physics.


title: Measuring satisfaction in societies with opinion leaders and mediators

abstract:
  An opinion leader-follower model (OLF) is a two-action collective
decision-making model for societies, in which three kinds of actors are
considered: "opinion leaders", "followers", and "independent actors". In OLF
the initial decision of the followers can be modified by the influence of the
leaders. Once the final decision is set, a collective decision is taken
applying the simple majority rule. We consider a generalization of \OLF, the
gOLF models which allow collective decision taken by rules different from the
single majority rule. Inspired in this model we define two new families of
collective decision-making models associated with cooperative influence games.
We define the "oblivious" and "non-oblivious" influence models. We show that
gOLF models are non-oblivious influence models played on a two layered
bipartite influence graph.
  Together with OLF models, the Satisfaction measure was introduced and
studied. We analyze the computational complexity of the satisfaction measure
for gOLF models and the other collective decision-making models introduced in
the paper. We show that computing the satisfaction measure is #P-hard in all
the considered models except for the basic OLF inwhich the complexity remains
open. On the other hand, we provide two subfamilies of decision models in which
the satisfaction measure can be computed in polynomial time.
  Exploiting the relationship with influence games, we can relate the
satisfaction measure with the Rae index of an associated simple game. The Rae
index is closely related to the Banzhaf value. Thus, our results also extend
the families of simple games for which computing the Rae index and the Banzhaf
value is computationally hard.


title:
An Efficient Synthesis Algorithm for Parametric Markov Chains Against
  Linear Time Properties

abstract:
  In this paper, we propose an efficient algorithm for the parameter synthesis
of PLTL formulas with respect to parametric Markov chains. The PLTL formula is
translated to an almost fully partitioned B\"uchi automaton which is then
composed with the parametric Markov chain. We then reduce the problem to
solving an optimisation problem, allowing to decide the satisfaction of the
formula using an SMT solver. The algorithm works also for interval Markov
chains. The complexity is linear in the size of the Markov chain, and
exponential in the size of the formula. We provide a prototype and show the
efficiency of our approach on a number of benchmarks.


title:
Coherent perfect absorption mediated enhancement of transverse spin in a
  gap plasmon guide

abstract:
  We consider a symmetric gap plasmon guide (a folded Kretschmann
configuration) supporting both symmeric and antisymmetric coupled surface
plasmons. We calculate the transverse spin under illumination from both the
sides like in coherent perfect absorption (CPA), whereby all the incident light
can be absorbed to excite one of the modes of the structure. Significant
enhancement in the transverse spin is shown to be possible when the CPA dip and
the mode excitation are at the same frequency. The enhancement results from
CPA-mediated total transfer of the incident light to either of the coupled
modes and the associated large local fields. The transverse spin is localized
in the structure since in the ambient dielectric there are only incident plane
waves lacking any structure.


title: Maximal CP Violation in Minimal Seesaw Model

abstract:
  In the minimal seesaw model, we derive required constraints on Dirac neutrino
masses inducing maximal CP violation in neutrino oscillations. If the maximal
atmospheric neutrino mixing is further assumed, Dirac neutrino masses are
uniquely determined to respect $\mu$-$\tau$ flavored CP symmetry for neutrinos.


title: The structure of projective indecomposable modules for $A_n$, $n\leq 12$

abstract:
  This article gives the structure of all projective indecomposable modules in
blocks with non-cyclic defect group for $n\leq 11$, and almost all in the case
of $n=12$, leaving four simple modules for $p=2$ and one simple module for
$p=3$.


title: Tunable Weyl Points in Periodically Driven Nodal Line Semimetals

abstract:
  Weyl semimetals and nodal line semimetals are characterized by linear band
touching at zero-dimensional points and one-dimensional lines, respectively. We
predict that a circularly polarized light drives nodal line semimetals into
Weyl semimetals. The Floquet Weyl points thus obtained are tunable by the
incident light, which enables investigations of them in a highly controllable
manner. The transition from nodal line semimetals to Weyl semimetals is
accompanied by the emergence of a large and tunable anomalous Hall
conductivity. Our predictions are experimentally testable by transport
measurement in film samples or by pump-probe angle-resolved photoemission
spectroscopy.

categories: cond-mat.str-el cond-mat.mes-hall cond-mat.mtrl-sci cond-mat.quant-gas physics.optics