title: Propagation rules for (u,m,e,s)-nets and (u,e,s)-sequences

abstract:
  The classes of $(u,m,{\bf e},s)$-nets and $(u,{\bf e},s)$-sequences were
recently introduced by Tezuka, and in a slightly more restrictive form by Hofer
and Niederreiter. We study propagation rules for these point sets, which state
how one can obtain $(u,m,{\bf e},s)$-nets and $(u,{\bf e},s)$-sequences with
new parameter configurations from existing ones. In this way, we show
generalizations and extensions of several well-known construction methods that
have previously been shown for $(t,m,s)$-nets and $(t,s)$-sequences. We also
develop a duality theory for digital $(u,m,{\bf e},s)$-nets and present a new
construction of such nets based on global function fields.


title:
A Combination of Downward Continuation and Local Approximation for
  Harmonic Potentials

abstract:
  This paper presents a method for the approximation of harmonic potentials
that combines downward continuation of globally available data on a sphere
$\Omega_R$ of radius $R$ (e.g., a satellite's orbit) with locally available
data on a sphere $\Omega_r$ of radius $r<R$ (e.g., the spherical Earth's
surface). The approximation is based on a two-step algorithm motivated by
spherical multiscale expansions: First, a convolution with a scaling kernel
$\Phi_N$ deals with the downward continuation from $\Omega_R$ to $\Omega_r$,
while in a second step, the result is locally refined by a convolution on
$\Omega_r$ with a wavelet kernel $\tilde{\Psi}_N$. Different from earlier
multiscale approaches, it is not the primary goal to obtain an adaptive spatial
localization but to simultaneously optimize the related kernels $\Phi_N$,
$\tilde{\Psi}_N$ in such a way that the former behaves well for the downward
continuation while the latter shows a good localization on $\Omega_r$ in the
region where data is available. The concept is indicated for scalar as well as
vector potentials.


title: A Generative Product-of-Filters Model of Audio

abstract:
  We propose the product-of-filters (PoF) model, a generative model that
decomposes audio spectra as sparse linear combinations of "filters" in the
log-spectral domain. PoF makes similar assumptions to those used in the classic
homomorphic filtering approach to signal processing, but replaces hand-designed
decompositions built of basic signal processing operations with a learned
decomposition based on statistical inference. This paper formulates the PoF
model and derives a mean-field method for posterior inference and a variational
EM algorithm to estimate the model's free parameters. We demonstrate PoF's
potential for audio processing on a bandwidth expansion task, and show that PoF
can serve as an effective unsupervised feature extractor for a speaker
identification task.


title: Intrinsic weak derivatives and Sobolev spaces between manifolds

abstract:
  We define the notion of colocally weakly differentiable maps from a manifold
$M$ to a manifold $N$. If $p \ge 1$ and $M$ and $N$ are endowed with a
Riemannian metric, this allows us to define intrinsically the homogeneous
Sobolev space $\dot{W}^{1, p} (M, N)$. This new definition is equivalent with
the definition by embedding in the Euclidean space and with the definition of
Sobolev maps into a metric space. The colocal weak derivative is an approximate
derivative. The colocal weak differentiability is stable under the suitable
weak convergence. The Sobolev spaces can be endowed with various intrinsinc
distances that induce the same topology and for which the space is complete.


title:
Multiscale adaptive smoothing models for the hemodynamic response
  function in fMRI

abstract:
  In the event-related functional magnetic resonance imaging (fMRI) data
analysis, there is an extensive interest in accurately and robustly estimating
the hemodynamic response function (HRF) and its associated statistics (e.g.,
the magnitude and duration of the activation). Most methods to date are
developed in the time domain and they have utilized almost exclusively the
temporal information of fMRI data without accounting for the spatial
information. The aim of this paper is to develop a multiscale adaptive
smoothing model (MASM) in the frequency domain by integrating the spatial and
frequency information to adaptively and accurately estimate HRFs pertaining to
each stimulus sequence across all voxels in a three-dimensional (3D) volume. We
use two sets of simulation studies and a real data set to examine the finite
sample performance of MASM in estimating HRFs. Our real and simulated data
analyses confirm that MASM outperforms several other state-of-the-art methods,
such as the smooth finite impulse response (sFIR) model.


title:
Anisotropy of excitation and relaxation of photogenerated Dirac
  electrons in graphene

abstract:
  We investigate the polarization dependence of the carrier excitation and
relaxation in epitaxial multilayer graphene. Degenerate pump-probe experiments
with a temporal resolution of 30 fs are performed for different rotation angles
of the pump-pulse polarization with respect to the polarization of the probe
pulse. A pronounced dependence of the pump-induced transmission on this angle
is found. It reflects a strong anisotropy of the pump-induced occupation of
photogenerated carriers in momentum space even though the band structure is
isotropic. Within 150 fs after excitation an isotropic carrier distribution is
established. Our observations imply the predominant role of collinear
scattering preserving the initially optically generated anisotropy in the
carrier distribution. The experiments are well described by microscopic time-,
momentum, and angle-resolved modelling, which allows us to unambiguously
identify non-collinear carrier-phonon scattering to be the main relaxation
mechanism giving rise to an isotropic distribution in the first hundred fs
after optical excitation.


title:
Shape Derivatives for the Compressible Navier-Stokes Equations in
  Variational Form

abstract:
  Shape optimization based on surface gradients and the Hadarmard-form is
considered for a compressible viscous fluid. Special attention is given to the
difference between the 'function composition' approach involving local shape
derivatives and an alternate methodology based on the weak form of the state
equation. The resulting gradient expressions are found to be equal only if the
existence of a strong form solution is assumed. Surface shape derivatives based
on both formulations are implemented within a Discontinuous Galerkin flow
solver of variable order. The gradient expression stemming from the variational
approach is found to give superior accuracy when compared to finite
differences.


title:
Estimation of the shift parameter in regression models with unknown
  distribution of the observations

abstract:
  This paper is devoted to the estimation of the shift parameter in a
semiparametric regression model when the distribution of the observation times
is unknown. Hence, we propose to use a stochastic algorithm which takes into
account the estimation of the distribution of the observation times. We
establish the almost sure convergence of our estimator and the asymptotic
normality. The main result of the paper is that, with little assumptions on the
regularity of the regression function, the asymptotic variance obtained is the
same as when the distribution is known. In that sense, we improve the recent
work of Bercu and Fraysse.


title:
Quantized resonator field coupled to a current-biased Josephson junction
  in circuit QED

abstract:
  A Lagrangian formalism is used to derive the Hamiltonian for a $\lambda$/4
resonator shunted by a current-biased Josephson junction. The eigenstates and
the quantum dynamics of the system are analyzed numerically, and we show that
the system can function as an efficient detector of weak incident microwave
fields.


title:
BANYAN. II. Very Low Mass and Substellar Candidate Members to Nearby,
  Young Kinematic Groups With Previously Known Signs of Youth

abstract:
  We present Bayesian Analysis for Nearby Young AssociatioNs II (BANYAN II), a
modified Bayesian analysis for assessing the membership of later-than-M5
objects to any of several Nearby Young Associations (NYAs). In addition to
using kinematic information (from sky position and proper motion), this
analysis exploits 2MASS-WISE color-magnitude diagrams in which old and young
objects follow distinct sequences. As an improvement over our earlier work, the
spatial and kinematic distributions for each association are now modelled as
ellipsoids whose axes need not be aligned with the Galactic coordinate axes,
and we use prior probabilities matching the expected populations of the NYAs
considered versus field stars. We present an extensive contamination analysis
to characterize the performance of our new method. We find that Bayesian
probabilities are generally representative of contamination rates, except when
a parallax measurement is considered. In this case contamination rates become
significantly smaller and hence Bayesian probabilities for NYA memberships are
pessimistic. We apply this new algorithm to a sample of 158 objects from the
literature that are either known to display spectroscopic signs of youth or
have unusually red near-infrared colors for their spectral type. Based on our
analysis, we identify 25 objects as new highly probable candidates to NYAs,
including a new M7.5 bona fide member to Tucana-Horologium, making it the
latest-type member. In addition, we reveal that a known L2{\gamma} dwarf is
co-moving with a bright M5 dwarf, and we show for the first time that two of
the currently known ultra red L dwarfs are strong candidates to the AB Doradus
moving group. Several objects identified here as highly probable members to
NYAs could be free-floating planetary-mass objects if their membership is
confirmed.


title:
Radiative neutron capture on 9be, 14c, 14n, 15n and 16o at thermal and
  astrophysical energies

abstract:
  The total cross sections of the radiative neutron capture processes on 9Be,
14C, 14N, 15N, and 16O are described in the framework of the modified potential
cluster model with the classification of orbital states according to Young
tableaux. The continued interest in the study of these reactions is due, on the
one hand, to the important role played by this process in the analysis of many
fundamental properties of nuclei and nuclear reactions, and, on the other hand,
to the wide use of the capture cross section data in the various applications
of nuclear physics and nuclear astrophysics, and, also, to the importance of
the analysis of primordial nucleosynthesis in the Universe. This article is
devoted to the description of results for the processes of the radiative
neutron capture on certain light atomic nuclei at thermal and astrophysical
energies. The considered capture reactions are not part of stellar
thermonuclear cycles, but involve in the reaction chains of inhomogeneous Big
Bang models.


title:
Regularity of stable solutions to semilinear elliptic equations on
  Riemannian models

abstract:
  We consider the reaction-diffusion problem $-\Delta_g u = f(u)$ in
$\mathcal{B}_R$ with zero Dirichlet boundary condition, posed in a geodesic
ball $\mathcal{B}_R$ with radius $R$ of a Riemannian model $(M,g)$. This class
of Riemannian manifolds includes the classical \textit{space forms}, i.e., the
Euclidean, elliptic, and hyperbolic spaces. For the class of semistable
solutions we prove radial symmetry and monotonicity. Furthermore, we establish
$L^\infty$, $L^p$, and $W^{1,p}$ estimates which are optimal and do not depend
on the nonlinearity $f$. As an application, under standard assumptions on the
nonlinearity $\lambda f(u)$, we prove that the corresponding extremal solution
$u^*$ is bounded whenever $n\leq9$. To establish the optimality of our
regularity results we find the extremal solution for some exponential and power
nonlinearities using an improved weighted Hardy inequality.


title:
Quantum-limited amplification and parametric instability in the reversed
  dissipation regime of cavity optomechanics

abstract:
  Cavity optomechanical phenomena, such as cooling, amplification or
optomechanically induced transparency, emerge due to a strong imbalance in the
dissipation rates of the parametrically coupled electromagnetic and mechanical
resonators. Here we analyze the reversed dissipation regime where the
mechanical energy relaxation rate exceeds the energy decay rate of the
electromagnetic cavity. We demonstrate that this regime allows for
mechanically-induced amplification (or cooling) of the electromagnetic mode.
Gain, bandwidth, and added noise of this electromagnetic amplifier are derived
and compared to amplification in the normal dissipation regime. In addition, we
analyze the parametric instability, i.e. optomechanical Brillouin lasing, and
contrast it to conventional optomechanical phonon lasing. Finally, we propose
an experimental scheme that realizes the reversed dissipation regime using
parametric coupling and optomechanical cooling with a second electromagnetic
mode enabling quantum-limited amplification. Recent advances in high-Q
superconducting microwave resonators make the reversed dissipation regime
experimentally realizable.


title: Adsorbate Electric Fields on a Cryogenic Atom Chip

abstract:
  We investigate the behaviour of electric fields originating from adsorbates
deposited on a cryogenic atom chip as it is cooled from room temperature to
cryogenic temperature. Using Rydberg electromagnetically induced transparency
we measure the field strength versus distance from a 1 mm square of YBCO
patterned onto a YSZ chip substrate. We find a localized and stable dipole
field at room temperature and attribute it to a saturated layer of chemically
adsorbed rubidium atoms on the YBCO. As the chip is cooled towards 83 K we
observe a change in sign of the electric field as well as a transition from a
localized to a delocalized dipole density. We relate these changes to the onset
of physisorption on the chip surface when the van der Waals attraction
overcomes the thermal desorption mechanisms. Our findings suggest that, through
careful selection of substrate materials, it may be possible to reduce the
electric fields caused by atomic adsorption on chips, opening up experiments to
controlled Rydberg-surface coupling schemes.


title: Principled Non-Linear Feature Selection

abstract:
  Recent non-linear feature selection approaches employing greedy optimisation
of Centred Kernel Target Alignment(KTA) exhibit strong results in terms of
generalisation accuracy and sparsity. However, they are computationally
prohibitive for large datasets. We propose randSel, a randomised feature
selection algorithm, with attractive scaling properties. Our theoretical
analysis of randSel provides strong probabilistic guarantees for correct
identification of relevant features. RandSel's characteristics make it an ideal
candidate for identifying informative learned representations. We've conducted
experimentation to establish the performance of this approach, and present
encouraging results, including a 3rd position result in the recent ICML black
box learning challenge as well as competitive results for signal peptide
prediction, an important problem in bioinformatics.


title: Origin Of the enhanced flexoelectricity of relaxor ferroelectrics

abstract:
  We have measured the bending-induced polarization of Pb(Mg1/3Nb2/3)O3-PbTiO3
single crystals with compositions at the relaxor-ferroelectric phase boundary.
The crystals display very large flexoelectricity, with flexocoupling
coefficients an order of magnitude bigger than the theoretical upper limit set
by the theories of Kogan and Tagantsev. This enhancement persists in the
paraphrase up to a temperature T* that coincides with the start of elastic
softening in the crystals. Analysis of the temperature dependence and
cross-correlation between flexoelectric, dielectric and elastic properties
indicates that the large bendinginduced polarization of relaxor ferroelectrics
is not caused by intrinsically giant flexoelectricity, but by the reorientation
of polar nanotwins that become ferroelastically active below T*.


title:
Asymptotic analysis for radial sign-changing solutions of the
  Brezis-Nirenberg problem

abstract:
  We study the asymptotic behavior, as $\lambda \rightarrow 0$, of least energy
radial sign-changing solutions $u_\lambda$, of the Brezis-Nirenberg problem
  \begin{equation*} \begin{cases} -\Delta u = \lambda u + |u|^{2^* -2}u &
\hbox{in}\ B_1\\ u=0 & \hbox{on}\ \partial B_1, \end{cases} \end{equation*}
where $\lambda >0$, $2^*=\frac{2n}{n-2}$ and $B_1$ is the unit ball of $\R^n$,
$n\geq 7$.
  We prove that both the positive and negative part $u_\lambda^+$ and
$u_\lambda^-$ concentrate at the same point (which is the center) of the ball
with different concentration speeds. Moreover we show that suitable rescalings
of $u_\lambda^+$ and $u_\lambda^-$ converge to the unique positive regular
solution of the critical exponent problem in $\R^n$.
  Precise estimates of the blow-up rate of $\|u_\lambda^\pm\|_{\infty}$ are
given, as well as asymptotic relations between $\|u_\lambda^\pm\|_{\infty}$ and
the nodal radius $r_\lambda$.
  Finally we prove that, up to constant, $\lambda^{-\frac{n-2}{2n-8}}
u_\lambda$ converges in $C_{loc}^1(B_1-\{0\})$ to $G(x,0)$, where $G(x,y)$ is
the Green function of the Laplacian in the unit ball.


title:
Techniques to treat the continuum applied to electromagnetictransitions
  in $^8$Be

abstract:
  Bremsstrahlung emission in collisions between charged nuclei is equivalent to
nuclear gamma decay between continuum states. The way the continuum spectrum
can be treated is not unique, and efficiency and accuracy of cross section
calculations depend on the chosen method. In this work we describe, relate, and
compare three different methods in practical calculations of inelastic cross
sections, that is, by (i) treating the initial and final states as pure
continuum states on the real energy axis, (ii) discretizing the continuum
states on the real energy axis with a box boundary condition, and (iii) complex
rotation of the hamiltonian(complex scaling method). The electric quadrupole
transitions, $2^+ \rightarrow 0^+$ and $4^+ \rightarrow 2^+$, in
$\alpha+\alpha$ scattering are taken as an illustration.


title:
A refined error analysis for fixed-degree polynomial optimization over
  the simplex

abstract:
  We consider the problem of minimizing a fixed-degree polynomial over the
standard simplex. This problem is well known to be NP-hard, since it contains
the maximum stable set problem in combinatorial optimization as a special case.
In this paper, we revisit a known upper bound obtained by taking the minimum
value on a regular grid, and a known lower bound based on P\'olya's
representation theorem. More precisely, we consider the difference between
these two bounds and we provide upper bounds for this difference in terms of
the range of function values. Our results refine the known upper bounds in the
quadratic and cubic cases, and they asymptotically refine the known upper bound
in the general case.


title: Bottomonium and B results from full lattice QCD

abstract:
  We have developed two methods for handling $b$ quarks in lattice QCD. One
uses NRQCD (now improved to include radiative corrections) and the other uses
Highly Improved Staggered Quarks (HISQ), extrapolating to the $b$ quark from
lighter masses and using multiple lattice spacings to control discretisation
errors. Comparison of results for the two different methods gives confidence in
estimates of lattice QCD systematic errors, since they are very different in
these two cases. Here we show results for heavyonium hyperfine splittings and
vector current-current correlator moments using HISQ quarks, to add to earlier
results testing the heavy HISQ method with pseudoscalar mesons. We also show
the form factor for $B \rightarrow \pi l \nu$ decay at zero recoil using NRQCD
$b$ quarks and $u/d$ quarks with physical masses. This allows us to test the
soft pion theorem relation ($f_0(q^2_{max})=f_B/f_{\pi}$) accurately and we
find good agreement as $M_{\pi} \rightarrow 0$. }


title: Expansive automorphisms of totally disconnected, locally compact groups

abstract:
  We study automorphisms $\alpha$ of a totally disconnected, locally compact
group $G$ which are expansive in the sense that, for some identity
neighbourhood $U$, the sets $\alpha^n(U)$ (for integers $n$) intersect in the
trivial group. Notably, we prove that the automorphism induced by $\alpha$ on
$G/N$ for an $\alpha$-stable closed normal subgroup $N$ of $G$ is always
expansive. Further results involve the associated contraction groups $U_\alpha$
consisting of all $x$ in $G$ such that $\alpha^n(x) \to e$ as $n$ tends to
infinity. If $\alpha$ is expansive, then $W := U_\alpha U_{\alpha^{-1}}$ is an
open identity neighbourhood in $G$. We give examples where $W$ fails to be a
subgroup. However, $W$ is a nilpotent open subgroup whenever $G$ is a closed
subgroup of a general linear group over the $p$-adic numbers. Further results
are devoted to the divisible and torsion parts of $U_\alpha$, and to the
so-called "nub" $U_0$ of an expansive automorphism $\alpha$ (the intersection
of the closures of $U_\alpha$ and $U_{\alpha^{-1}}$).


title: Hereditarily hypercyclic subspaces

abstract:
  We say that a sequence of operators $(T_n)$ possesses hereditarily
hypercyclic subspaces along a sequence $(n_k)$ if for any subsequence
$(m_k)\subset(n_k)$, the sequence $(T_{m_k})$ possesses a hypercyclic subspace.
While so far no characterization of the existence of hypercyclic subspaces in
the case of Fr\'{e}chet spaces is known, we succeed to obtain a
characterization of sequences $(T_n)$ possessing hereditarily hypercyclic
subspaces along $(n_k)$, under the assumption that the sequence $(T_n)$
satisfies the Hypercyclicity Criterion along $(n_k)$. We also obtain a
characterization of operators possessing a hypercyclic subspace under the
assumption that $T$ satisfies the Frequent Hypercyclicity Criterion.


title:
Can the magnetic field in the Orion arm inhibit the growth of
  instabilities in the bow shock of Betelgeuse?

abstract:
  Many evolved stars travel through space at supersonic velocities, which leads
to the formation of bow shocks ahead of the star where the stellar wind
collides with the interstellar medium (ISM). Herschel observations of the bow
shock of $\alpha$-Orionis show that the shock is almost free of instabilities,
despite being, at least in theory, subject to both Kelvin-Helmholtz and
Rayleigh-Taylor instabilities. A possible explanation for the lack of
instabilities lies in the presence of an interstellar magnetic field. We wish
to investigate whether the magnetic field of the interstellar medium (ISM) in
the Orion arm can inhibit the growth of instabilities in the bow shock of
$\alpha$-Orionis. We used the code MPI-AMRVAC to make magneto-hydrodynamic
simulations of a circumstellar bow shock, using the wind parameters derived for
$\alpha$-Orionis and interstellar magnetic field strengths of $B\,=\,1.4,\,
3.0$, and $5.0\, \mu$G, which fall within the boundaries of the observed
magnetic field strength in the Orion arm of the Milky Way. Our results show
that even a relatively weak magnetic field in the interstellar medium can
suppress the growth of Rayleigh-Taylor and Kelvin-Helmholtz instabilities,
which occur along the contact discontinuity between the shocked wind and the
shocked ISM. The presence of even a weak magnetic field in the ISM effectively
inhibits the growth of instabilities in the bow shock. This may explain the
absence of such instabilities in the Herschel observations of $\alpha$-Orionis.


title: Fifty Years of TT Arietis

abstract:
  Results of photometric observations of the permanent negative superhumper TT
Ari in 1961/62 and 1966 are presented. Together with data from the literature
they are used to discuss the negative superhump amplitudes $A_{nSH}$ and the
amplitudes $A_{beat}$ of the modulation with the beat period $P_{beat}$. Both
amplitudes are shown to vary considerably from one season to another. Three
correlations are found: (1) between $A_{nSH}$ and $A_{beat}$, (2) between
$A_{nSH}$ and $P_{nSH}$, and (3) between $A_{beat}$ and $P_{beat}$.


title:
Special polynomials related to the supersymmetric eight-vertex model.
  II. Schr\"odinger equation

abstract:
  We show that symmetric polynomials previously introduced by the author
satisfy a certain differential equation. After a change of variables, it can be
written as a non-stationary Schr\"odinger equation with elliptic potential,
which is closely related to the Knizhnik--Zamolodchikov--Bernard equation and
to the canonical quantization of the Painlev\'e VI equation. In a subsequent
paper, this will be used to construct a four-dimensional lattice of tau
functions for Painlev\'e VI.


title:
A Search for Photometric Variability Towards M71 with the Near-Infrared
  Transiting ExoplanetS Telescope

abstract:
  We present the results of a high-cadence photometric survey of an
$11'\times11'$ field centred on the globular cluster M71, with the
Near-Infrared Transiting ExoplanetS Telescope. The aim of our survey is to
search for stellar variability and transiting giant exoplanets. This survey
differs from previous photometric surveys of M71 in that it is more sensitive
to lower amplitude ($\Delta M\leq0.02$ mag) and longer period ($P>2$ d)
variability than previous work on this cluster. We have discovered $17$ new
variable stars towards M71 and confirm the nature of $13$ previously known
objects, for which the orbital periods of $7$ are refined or newly determined.
Given the photometric precision of our high-cadence survey on the horizontal
branch of M71, we confirm the cluster is devoid of RR Lyrae variable stars
within the area surveyed. We present new $B$ and $V$ band photometry of the
stars in our sample from which we estimate spectral types of the variable
objects. We also search our survey data for transiting hot Jupiters and present
simulations of the expected number of detections. Approximately $1\,000$ stars
were observed on the main-sequence of M71 with sufficient photometric accuracy
to detect a transiting hot Jupiter, however none were found.


title:
Asymptotic formulas and inequalities for gamma function in terms of
  tri-gamma function

abstract:
  In the paper, the authors establish some asymptotic formulas and double
inequalities for the factorial $n!$ and the gamma function $\Gamma$ in terms of
the tri-gamma function $\psi'$.


title:
A unified framework for parabolic equations with mixed boundary
  conditions and diffusion on interfaces

abstract:
  In this paper we consider scalar parabolic equations in a general non-smooth
setting with emphasis on mixed interface and boundary conditions. In
particular, we allow for dynamics and diffusion on a Lipschitz interface and on
the boundary, where diffusion coefficients are only assumed to be bounded,
measurable and positive semidefinite. In the bulk, we additionally take into
account diffusion coefficients which may degenerate towards a Lipschitz
surface. For this problem class, we introduce a unified functional analytic
framework based on sesquilinear forms and show maximal regularity for the
corresponding abstract Cauchy problem.


title:
Towards an exact frame formulation of conformal higher spins in three
  dimensions

abstract:
  In this note we discuss some aspects of the frame formulation of conformal
higher spins in three dimensions. We give some exact formulae for the coupled
spin two - spin three part of the full higher spin theory and propose a star
product Lagrangian for all spins from two and up. Since there is no consistent
Lagrangian formulation based on the Poisson bracket we start the construction
from the field equations in this approximation of the star product. The higher
spin algebra is then realized in terms of classical variables which leads to
certain important simplifications that we take advantage of. The suggested
structure of the all-spin Lagrangian given here is, however, obtained using an
expansion of the star product beyond the Poisson bracket in terms of
multi-commutators and the Lagrangian should be viewed as a starting point for
the derivation of the full theory based on a star product. How to do this is
explained as well as how to include the coupling to scalar fields. We also
comment on the AdS/CFT relation to four dimensions.


title: Hard Lefschetz Theorem in $p$-adic cohomology

abstract:
  In this short paper, we give a $p$-adic analogue of the Hard Leftschetz
Theorem.


title:
Sub-dominant Type II Seesaw as an Origin of Non-zero $\theta_{13}$ in
  SO(10) model with TeV scale $Z^\prime$ Gauge Boson

abstract:
  We discuss a class of left-right symmetric models where the light neutrino
masses originate dominantly from type I seesaw mechanism along with a
sub-dominant type II seesaw contribution. The dominant type I seesaw gives rise
to tri-bimaximal type neutrino mixing whereas sub-dominant type II seesaw acts
as a small perturbation giving rise to non-zero $\theta_{13}$ in our model
which also has TeV scale right-handed neutrinos and $Z^\prime$ gauge boson
thereby making the model verifiable at current accelerator experiments.
Sub-dominant type II and dominant type I seesaw can be naturally accommodated
by allowing spontaneous breaking of D-parity and $SU(2)_R$ gauge symmetry at
high scale and allowing TeV scale breaking of $U(1)_{R} \times U(1)_{B-L}$ into
$U(1)_Y$. We also embed the left-right model in a non-supersymmetric $SO(10)$
grand unified theory (GUT) with verifiable TeV scale $Z^\prime$ gauge boson.
Drawing it to an end, we scrutinize in detail the evaluation of one-loop
renormalization group evolution for relevant gauge couplings and estimation of
the proton life time which can be accessible to the foreseeable experiments.
And in the aftermost part we make an estimation of branching ratio for lepton
flavor violating process $\mu \rightarrow e + \gamma $ as a function of type II
seesaw strength due to doubly charged component of the right handed Higgs
triplet with mass at the TeV scale, which can be accessible at ongoing
experiments.


title:
Variable relaxed schemes for multidimensional hyperbolic conservation
  laws

abstract:
  We present a new class of component-wise numerical schemes that are in the
family of relaxation formulations, originally introduced by [S. Jin and Z. P.
Xin, Comm. Pure Appl. Math., 48(1995), pp. 235-277]. The relaxation framework
enables the construction of schemes that are free of nonlinear Riemann solvers
and are independent of the underlying eigenstructure of the problem. The
constant relaxation schemes proposed by Jin & Xin can however introduce strong
numerical diffusion, especially when the maximum characteristic speeds are high
compared to the average speeds in the domain. We propose a general class of
variable relaxation formulations for multidimensional systems of conservation
laws which utilizes estimates of local maximum and minimum speeds to arrive at
more accurate relaxation schemes, irrespective of the contrast in maximum and
average characteristic speeds. First and second order variable relaxation
methods are presented for general nonlinear systems in one and two spatial
dimensions, along with monotonicity and TVD (Total Variation Diminishing)
properties for the 1D schemes. The effectiveness of the schemes is demonstrated
on a test suite that includes Burgers' equation, the weakly hyperbolic
Engquist-Runborg problem, as well as the weakly hyperbolic gas injection
displacements that are governed by strong nonlinear coupling thus making them
highly sensitive to numerical diffusion. In the latter examples the second
order Jin-Xin scheme fails to capture the fronts reasonably, when both the
first and second order variable relaxed schemes produce the displacement
profiles sharply.


title: Layer methods for Navier-Stokes equations with additive noise

abstract:
  We propose and study a number of layer methods for stochastic Navier-Stokes
equations (SNSE) with spatial periodic boundary conditions and additive noise.
The methods are constructed using conditional probabilistic representations of
solutions to SNSE and exploiting ideas of the weak sense numerical integration
of stochastic differential equations. We prove some convergence results for the
proposed methods. Results of numerical experiments on two model problems are
presented.


title:
On the form of the relative entropy between measures on the space of
  continuous functions

abstract:
  In this paper we derive an integral (with respect to time) representation of
the relative entropy (or Kullback-Leibler Divergence) between measures mu and P
on the space of continuous functions from time 0 to T. The underlying measure P
is a weak solution to a Martingale Problem with continuous coefficients. Since
the relative entropy governs the exponential rate of convergence of the
empirical measure (according to Sanov's Theorem), this representation is of use
in the numerical and analytical investigation of finite-size effects in systems
of interacting diffusions.


title: Non-parametric Bayesian modeling of complex networks

abstract:
  Modeling structure in complex networks using Bayesian non-parametrics makes
it possible to specify flexible model structures and infer the adequate model
complexity from the observed data. This paper provides a gentle introduction to
non-parametric Bayesian modeling of complex networks: Using an infinite mixture
model as running example we go through the steps of deriving the model as an
infinite limit of a finite parametric model, inferring the model parameters by
Markov chain Monte Carlo, and checking the model's fit and predictive
performance. We explain how advanced non-parametric models for complex networks
can be derived and point out relevant literature.


title:
Photometry of the progenitor of Nova Del 2013 (V339 Del) and calibration
  of a deep BVRI photometric

abstract:
  The Asiago plate archive has been searched for old plates covering the region
of the sky containing Nova Del 2013 (V339 Del). The brightness of the
progenitor was measured against a deep BVRI photometric sequence that we
calibrated on purpose. The mean brightness of the progenitor on Asiago plates
is <B>=17.27 and <V>=17.6, for a mean color (B-V) = -0.33. The recorded total
amplitude of variation in B band is 0.9 mag. Color and variability are in
agreement with a progenitor dominated by the emission from an accretion disc.
The progenitor was marginally detected also by the APASS all sky survey on
April 2012. We have stacked the CCD images from three individual visits and
measured the progenitor at B=17.33+/-0.09 and V=17.06+/-0.10 mag.


title: The Sparse Principal Component of a Constant-rank Matrix

abstract:
  The computation of the sparse principal component of a matrix is equivalent
to the identification of its principal submatrix with the largest maximum
eigenvalue. Finding this optimal submatrix is what renders the problem
${\mathcal{NP}}$-hard. In this work, we prove that, if the matrix is positive
semidefinite and its rank is constant, then its sparse principal component is
polynomially computable. Our proof utilizes the auxiliary unit vector technique
that has been recently developed to identify problems that are polynomially
solvable. Moreover, we use this technique to design an algorithm which, for any
sparsity value, computes the sparse principal component with complexity
${\mathcal O}\left(N^{D+1}\right)$, where $N$ and $D$ are the matrix size and
rank, respectively. Our algorithm is fully parallelizable and memory efficient.


title: Support for Error Tolerance in the Real-Time Transport Protocol

abstract:
  Streaming applications often tolerate bit errors in their received data well.
This is contrasted by the enforcement of correctness of the packet headers and
payload by network protocols. We investigate a solution for the Real-time
Transport Protocol (RTP) that is tolerant to errors by accepting erroneous
data. It passes potentially corrupted stream data payloads to the codecs. If
errors occur in the header, our solution recovers from these by leveraging the
known state and expected header values for each stream. The solution is fully
receiver-based and incrementally deployable, and as such requires neither
support from the sender nor changes to the RTP specification. Evaluations show
that our header error recovery scheme can recover from almost all errors, with
virtually no erroneous recoveries, up to bit error rates of about 10%.


title:
Duality in refined Sobolev-Malliavin spaces and weak approximations of
  SPDE

abstract:
  We introduce a new family of refined Sobolev-Malliavin spaces that capture
the integrability in time of the Malliavin derivative. We consider duality in
these spaces and derive a Burkholder type inequality in a dual norm. The theory
we develop allows us to prove weak convergence with essentially optimal rate
for numerical approximations in space and time of semilinear parabolic
stochastic evolution equations driven by Gaussian additive noise. In
particular, we combine a standard Galerkin finite element method with backward
Euler timestepping. The method of proof does not rely on the use of the
Kolmogorov equation or the It\={o} formula and is therefore non-Markovian in
nature. Test functions satisfying polynomial growth and mild smoothness
assumptions are allowed, meaning in particular that we prove convergence of
arbitrary moments with essentially optimal rate.


title:
Weak Convergence of the Sequential Empirical Process of some Long-Range
  Dependent Sequences with Respect to a Weighted Norm

abstract:
  Let $(X_k)_{k\geq1}$ be a Gaussian long-range dependent process with
$EX_1=0$, $EX_1^2=1$ and covariance function $r(k)=k^{-D}L(k)$. For any
measurable function $G$ let $(Y_k)_{k\geq1}=(G(X_k))_{k\geq1}$. We study the
asymptotic behaviour of the associated sequential empirical process
$\left(R_N(x,t)\right)$ with respect to a weighted norm $\|\cdot\|_w$. We show
that, after an appropriate normalization, $\left(R_N(x,t)\right)$ converges
weakly in the space of c\`adl\`ag functions with finite weighted norm to a
Hermite process.


title:
Intermittent dust mass loss from activated asteroid P/2013 P5
  (PANSTARRS)

abstract:
  We present observations and models of the dust environment of activated
asteroid P/2013 P5 (PANSTARRS). The object displayed a complex morphology
during the observations, with the presence of multiple tails. We combined our
own observations, all made with instrumentation attached to the 10.4m Gran
Telescopio Canarias (GTC) on La Palma, with previously published Hubble Space
Telescope (HST) images to build a model aimed at fitting all the observations.
Altogether, the data cover a full 3-month period of observations which can be
explained by an intermittent dust loss. The most plausible scenario is that of
an asteroid rotating with the spinning axis oriented perpendicular to the orbit
plane and loosing mass from the equatorial region, consistent with a rotational
break-up. Assuming that the ejection velocity of the particles
(v$\sim$0.02-0.05 m s$^{-1}$) corresponds to the escape velocity, the object
diameter is constrained to $\sim$30-130 m for bulk densities 3000 to 1000 kg
m$^{-3}$.


title: Relative frequencies of supernovae versus properties of spiral hosts

abstract:
  In this work, we present an analysis of SNe number ratios in spiral galaxies
with different morphological subtypes, luminosities, sSFR, and metallicities,
to provide important information about the physical properties of the
progenitor populations.


title: Higher order relations for ADE-type generalized q-Onsager algebras

abstract:
  Let $\{A_j|j=0,1,...,rank(g)\}$ be the fundamental generators of the
generalized $q-$Onsager algebra $\cal O_{q}(\widehat{g})$ introduced in
\cite{BB1}, where $\widehat{g}$ is a simply-laced affine Lie algebra. New
relations between certain monomials of the fundamental generators - indexed by
the integer $r\in\mathbb{Z}^{+}$ - are conjectured. These relations can be seen
as deformed analogues of Lusztig's $r-$th higher order $q-$Serre relations
associated with ${\cal U}_q({\widehat g})$, which are recovered as special
cases. The relations are proven for $r\leq 5$. For $r$ generic, several
supporting evidences are presented.

categories: math-ph cond-mat.stat-mech hep-th math.MP math.QA


title: Band symmetries of mixed-valence topological insulator: SmB6

abstract:
  We have investigated the band structure and the band symmetry of
mixed-valence insulator SmB$_{6}$ systematically within the density functional
theory (DFT). We have analyzed the symmetries and characters of Sm $4f$ and
$5d$ bands near the Fermi level ($E_F$) in terms of the non-relativistic real
cubic bases as well as the relativistic complex bases incorporating the
spin-orbit coupling and the cubic crystal field. Further, we have found that
the semi-core band located at $\sim 15$ eV below $E_F$ has the mixed parity and
thereby affects the parity eigenvalues of the special ${\bf k}$-points
considerably. We have discussed the possible surface states and topological
class of SmB$_{6}$, based on the bulk parity tables.


title:
A Detailed Numerical Analysis of Asymmetrical Density Distribution in
  Saturn's F ring During an Encounter with Prometheus

abstract:
  Saturn's rings, reminiscent of an early Solar System present a unique
opportunity to investigate experimentally some mechanisms thought to be
responsible for planet and planetesimal formation in protoplanetary discs. Here
we extended the comparison of our numerical models of Prometheus encountering
the F ring employing non-interacting and interacting particles. Higher
resolution analysis revealed that the density increases known to exist at
channel edges is more complex and localised than previously thought. Asymmetry
between density increases on channel edges revealed that the channel edge
facing way from Prometheus to be the most stable but with lowest maximum
increases. However, on the channel edge facing Prometheus the interacting model
showed large chaotic fluctuations in the maximum density of some clumps, much
larger than those of the other channel. The likely cause of this asymmetry is a
variance in localised turbulence introduced into the F ring by Prometheus. High
resolution velocity dispersion maps showed that there was a spatial link
between the highest densities and the highest velocity dispersions in the
interacting model. Thus suggesting that the high velocity dispersion we see is
the reason for the observed inhomogeneous distribution of fans (evidence of
embedded moonlets) on some of the channel edges facing Prometheus.


title:
The generalized pseudospectral approach to the bound states of Hulthen
  and Yukawa potentials

abstract:
  The generalized pseudospectral method is employed to calculate the bound
states of Hulth\'en and Yukawa potentials in quantum mechanics, with special
emphases on higher excited states and stronger couplings. Accurate energy
eigenvalues, expectation values and radial probability densities are obtained
through a nonuniform and optimal spatial discretization of the radial
Schr\"odinger equation. Results accurate up to thirteen to fourteen significant
figures are reported for all the 55 eigenstates of both these potentials with
$n\leq$10 for arbitrary values of the screening parameters covering a wide
range of interaction. Furthermore, excited states as high as up to $n=17$ have
been computed with good accuracy for both these potentials. Excellent agreement
with the available literature data has been observed in all cases. The $n>6$
states of Yukawa potential has been considerably improved over all other
existing results currently available, while the same for Hulth\'en potential
are reported here for the first time. Excepting the $1s$ and $2s$ states of
Yukawa potential, the present method surpasses in accuracy all other existing
results in the stronger coupling region for all other states of both these
systems. This offers a simple and efficient scheme for the accurate calculation
of these and other screened Coulomb potentials.


title:
Trajectory composition of Poisson time changes and Markov counting
  systems

abstract:
  Changing time of simple continuous-time Markov counting processes by
independent unit-rate Poisson processes results in Markov counting processes
for which we provide closed-form transition rates via composition of
trajectories and with which we construct novel, simpler infinitesimally
over-dispersed processes.


title: Band antiferromagnetism in a two-band model for iron pnictides

abstract:
  In this work I investigate a two-band Hubbard model using the Gutzwiller
wavefunction. The tight-binding part of the model was constructed to have a
gapless spin-density wave state which leads to Dirac points in the
bandstructure, a common feature of many iron-pnictide compounds. For quarter,
half and three-quarter fillings I show that the Hund's rule coupling has a
large impact on the metal-insulator transition in the paramagnetic phase. For
the half-filled model in the antiferromagnetic phase, the magnetism evolves in
a Stoner-like behavior and the size of the ordered moment is mainly determined
by the Hubbard interaction. As the Hund's coupling plays a minor role in this
state, the model does not describe a Hund's metal which is in contrast to more
realistic models for iron-pnictide compounds.


title: Co-jumps and Markov counting systems in random environments

abstract:
  We provide transition rates for Markov counting systems subject to correlated
environmental noises motivated by multi-strain disease models. Such noises
induce simultaneous counts, which can help model infinitesimal count
correlation (regardless of whether such correlation is due to correlated
noises).


title: Modern Statistical Methods in Oceanography: A Hierarchical Perspective

abstract:
  Processes in ocean physics, air-sea interaction and ocean biogeochemistry
span enormous ranges in spatial and temporal scales, that is, from molecular to
planetary and from seconds to millennia. Identifying and implementing
sustainable human practices depend critically on our understandings of key
aspects of ocean physics and ecology within these scale ranges. The set of all
ocean data is distorted such that three- and four-dimensional (i.e.,
time-dependent) in situ data are very sparse, while observations of surface and
upper ocean properties from space-borne platforms have become abundant in the
past few decades. Precisions in observations of all types vary as well. In the
face of these challenges, the interface between Statistics and Oceanography has
proven to be a fruitful area for research and the development of useful models.
With the recognition of the key importance of identifying, quantifying and
managing uncertainty in data and models of ocean processes, a hierarchical
perspective has become increasingly productive. As examples, we review a
heterogeneous mix of studies from our own work demonstrating Bayesian
hierarchical model applications in ocean physics, air-sea interaction, ocean
forecasting and ocean ecosystem models. This review is by no means exhaustive
and we have endeavored to identify hierarchical modeling work reported by
others across the broad range of ocean-related topics reported in the
statistical literature. We conclude by noting relevant ocean-statistics
problems on the immediate research horizon, and some technical challenges they
pose, for example, in terms of nonlinearity, dimensionality and computing.


title: Cubic surfaces with one rational line over finite fields

abstract:
  Let Fq be a finite field with q=8 or q at least 16. Let S be a smooth cubic
surface defined over Fq containing at least one rational line. We use a
pigeonhole principle to prove that all the rational points on S are generated
via tangent and secant operations from a single point.


title: Invariant metrics for the quaternionic Hardy space

abstract:
  Riemannian metrics on the unit ball of the quaternions, which are naturally
associated with the reproducing kernel Hilbert spaces. We study the metric
arising from the Hardy space in detail. We show that, in contrast to the
one-complex variable case, no Riemannian metric is invariant under regular
self-maps of the quaternionic ball.


title: Well-Quasi-Order for Permutation Graphs Omitting a Path and a Clique

abstract:
  We consider well-quasi-order for classes of permutation graphs which omit
both a path and a clique. Our principle result is that the class of permutation
graphs omitting $P_5$ and a clique of any size is well-quasi-ordered. This is
proved by giving a structural decomposition of the corresponding permutations.
We also exhibit three infinite antichains to show that the classes of
permutation graphs omitting $\{P_6,K_6\}$, $\{P_7,K_5\}$, and $\{P_8,K_4\}$ are
not well-quasi-ordered.


title: In memory of M. I. Polikarpov

abstract:
  This obituary is devoted to M. I. Polikarpov (28.12.1952 - 18.07.2013), our
teacher, our colleague, our friend. We recollect some facts of his biography
and stages of his scientific career, and make a brief review of some of his
most known scientific works. We conclude with some messages of condolence which
were received from his colleagues and friends after his sudden death.


title: Remarks on the $\mathbf Q$-curvature flow

abstract:
  The main purpose of this short note is to point out that the negative
gradient flow for the prescribed $\mathbf Q$-curvature problem on $S^n$ can be
extended to handle the case that the $\mathbf Q$-curvature candidate $f$ may
change signs.


title:
Operads with general groups of equivariance, and some 2-categorical
  aspects of operads in Cat

abstract:
  We give a definition of an operad with general groups of equivariance
suitable for use in any symmetric monoidal category with appropriate colimits.
We then apply this notion to study the 2-category of algebras over an operad in
Cat. We show that any operad is finitary, that an operad is cartesian if and
only if the group actions are nearly free (in a precise fashion), and that the
existence of a pseudo-commutative structure largely depends on the groups of
equivariance. We conclude by showing that the operad for strict braided
monoidal categories has two canonical pseudo-commutative structures.


title: Estimating time-changes in noisy L\'evy models

abstract:
  In quantitative finance, we often model asset prices as a noisy Ito
semimartingale. As this model is not identifiable, approximating by a
time-changed Levy process can be useful for generative modelling. We give a new
estimate of the normalised volatility or time change in this model, which
obtains minimax convergence rates, and is unaffected by infinite-variation
jumps. In the semimartingale model, our estimate remains accurate for the
normalised volatility, obtaining convergence rates as good as any previously
implied in the literature.


title: Containment of Schema Mappings for Data Exchange (Preliminary Report)

abstract:
  In data exchange, data are materialised from a source schema to a target
schema, according to suitable source-to-target constraints. Constraints are
also expressed on the target schema to represent the domain of interest. A
schema mapping is the union of the source-to-target and of the target
constraints.
  In this paper, we address the problem of containment of schema mappings for
data exchange, which has been recently proposed in this framework as a step
towards the optimization of data exchange settings. We refer to a natural
notion of containment that relies on the behaviour of schema mappings with
respect to conjunctive query answering, in the presence of so-called LAV TGDs
as target constraints. Our contribution is a practical technique for testing
the containment based on the existence of a homomorphism between special
"dummy" instances, which can be easily built from schema mappings.
  We argue that containment of schema mappings is decidable for most practical
cases, and we set the basis for further investigations in the topic. This paper
extends our preliminary results.


title: Energy loss in unstable QGP - problem of the upper cut-off

abstract:
  The energy loss of a highly energetic parton in a weakly coupled quark-gluon
plasma is studied as an initial value problem. An extremely prolate plasma,
where the momentum distribution is infinitely elongated along one direction, is
considered. The energy loss is strongly time and direction dependent and its
magnitude can much exceed the equilibrium value. It is logarithmically
ultraviolet divergent. We argue that a good approximation to the energy loss
can be obtained if this divergence is cut off with the parton energy.


title: Deep Separability of Ontological Constraints

abstract:
  When data schemata are enriched with expressive constraints that aim at
representing the domain of interest, in order to answer queries one needs to
consider the logical theory consisting of both the data and the constraints.
Query answering in such a context is called ontological query answering.
Commonly adopted database constraints in this field are tuple-generating
dependencies (TGDs) and equality-generating dependencies (EGDs). It is well
known that their interaction leads to intractability or undecidability of query
answering even in the case of simple subclasses. Several conditions have been
found to guarantee separability, that is lack of interaction, between TGDs and
EGDs. Separability makes EGDs (mostly) irrelevant for query answering and
therefore often guarantees tractability, as long as the theory is satisfiable.
In this paper we review the two notions of separability found in the
literature, as well as several syntactic conditions that are sufficient to
prove them. We then shed light on the issue of satisfiability checking, showing
that under a sufficient condition called deep separability it can be done by
considering the TGDs only.
  We show that, fortunately, in the case of TGDs and EGDs, separability implies
deep separability. This result generalizes several analogous ones, proved ad
hoc for particular classes of constraints. Applications include the class of
sticky TGDs and EGDs, for which we provide a syntactic separability condition
which extends the analogous one for linear TGDs; preliminary experiments show
the feasibility of query answering in this case.


title:
Tightened estimation can improve the key rate of MDI-QKD by more than
  $100\%$

abstract:
  We present formulas to tightly upper bound the phase-flip errors in decoy
state method by using 4 intensities. Our result compressed the bound to about a
quarter of known result for MDI-QKD. Based on this, we find that the key rate
is improved by more than $100\%$ given weak coherent state sources (WCS), and
even more than $200\%$ with the heralded single-photon sources (HSPS).


title: Perfect signaling among three parties violating predefined causal order

abstract:
  The paradigmatic view where information is seen as a more fundamental concept
than the laws of physics leads to a different understanding of spacetime where
the causal order of events emerges from correlations between random variables
representing physical quantities. In particular, such an information-theoretic
approach does not enforce a global spacetime structure. By following this path,
we conclude that perfect signaling correlations among three parties are
possible which do not obey the restrictions imposed by global spacetime. We
show this using a recent framework based on the sole assumptions that locally,
quantum theory is valid and random variables can be described by probability
distributions. Our result is of zero-error type and is an analog to a
tripartite appearance of quantum non-locality which manifests itself by
satisfying a condition with certainty whereas the same is impossible for any
local theory.


title: Search for binary central stars of the SMC PNe

abstract:
  The Optical Gravitational Lensing Experiment (OGLE), originally designed to
search for microlensing events, provides a rich and uniform data set suitable
for studying the variability of certain types of objects. We used the OGLE data
to study the photometry of central stars of planetary nebulae (PNe) in the
Small Magellanic Cloud (SMC). In particular, we searched for close binary
central stars with the aim to constrain the binary fraction and period
distribution in the SMC. We also searched for PNe mimics and removed them from
the PNe sample. We identified 52 counterparts of PNe in the SMC in the I-band
images from the OGLE-II and OGLE-III surveys. We analysed the time-series
photometry of the PNe. Spectra of the photometric variables were obtained to
constrain the nature of the objects or search for additional evidence for
binarity. Eight variables were found. Of these, seven objects are PNe mimics,
including one symbiotic star candidate. One close binary central star of PN
with a period of 1.15 or 2.31 day was discovered. The obtained binary fraction
for the SMC PNe and the observational biases are discussed in terms of the OGLE
observations.


title:
Global Distribution of Water Vapor and Cloud Cover--Sites for High
  Performance THz Applications

abstract:
  Absorption of terahertz radiation by atmospheric water vapor is a serious
impediment for radio astronomy and for long-distance communications.
Transmission in the THz regime is dependent almost exclusively on atmospheric
precipitable water vapor (PWV). Though much of the Earth has PWV that is too
high for good transmission above 200 GHz, there are a number of dry sites with
very low attenuation. We performed a global analysis of PWV with
high-resolution measurements from the Moderate Resolution Imaging Spectrometer
(MODIS) on two NASA Earth Observing System (EOS) satellites over the year of
2011. We determined PWV and cloud cover distributions and then developed a
model to find transmission and atmospheric radiance as well as necessary
integration times in the various windows. We produced global maps over the
common THz windows for astronomical and satellite communications scenarios.
Notably, we show that up through 1 THz, systems could be built in excellent
sites of Chile, Greenland and the Tibetan Plateau, while Antarctic performance
is good to 1.6 THz. For a ground-to-space communication link up through 847
GHz, we found several sites in the Continental United States where mean
atmospheric attenuation is less than 40 dB; not an insurmountable challenge for
a link.


title: A Monte Carlo method for optimal portfolio executions

abstract:
  Traders are often faced with large block orders in markets with limited
liquidity and varying volatility. Executing the entire order at once usually
incurs a large trading cost because of this limited liquidity. In order to
minimize this cost traders split up large orders over time. Varying volatility
however implies that they now take on price risk, as the underlying assets'
prices can move against the traders over the execution period. This execution
problem therefore requires a careful balancing between trading slow to reduce
liquidity cost and trading fast to reduce the volatility cost. R. Almgren
solved this problem for a market with one asset and stochastic liquidity and
volatility parameters, using a mean-variance framework. This leads to a
nonlinear PDE that needs to be solved numerically. We propose a different
approach using (quasi-)Monte Carlo which can handle any number of assets.
Furthermore, our method can be run in real-time and allows the trader to change
the parameters of the underlying stochastic processes on-the-fly.


title: Non-KPZ modes in two-species driven diffusive systems

abstract:
  Using mode coupling theory and dynamical Monte-Carlo simulations we
investigate the scaling behaviour of the dynamical structure function of a
two-species asymmetric simple exclusion process, consisting of two coupled
single-lane asymmetric simple exclusion processes. We demonstrate the
appearence of a superdiffusive mode with dynamical exponent $z=5/3$ in the
density fluctuations, along with a KPZ mode with $z=3/2$ and argue that this
phenomenon is generic for short-ranged driven diffusive systems with more than
one conserved density. When the dynamics is symmetric under the interchange of
the two lanes a diffusive mode with $z=2$ appears instead of the non-KPZ
superdiffusive mode.


title: Group-sparse Embeddings in Collective Matrix Factorization

abstract:
  CMF is a technique for simultaneously learning low-rank representations based
on a collection of matrices with shared entities. A typical example is the
joint modeling of user-item, item-property, and user-feature matrices in a
recommender system. The key idea in CMF is that the embeddings are shared
across the matrices, which enables transferring information between them. The
existing solutions, however, break down when the individual matrices have
low-rank structure not shared with others. In this work we present a novel CMF
solution that allows each of the matrices to have a separate low-rank structure
that is independent of the other matrices, as well as structures that are
shared only by a subset of them. We compare MAP and variational Bayesian
solutions based on alternating optimization algorithms and show that the model
automatically infers the nature of each factor using group-wise sparsity. Our
approach supports in a principled way continuous, binary and count observations
and is efficient for sparse matrices involving missing data. We illustrate the
solution on a number of examples, focusing in particular on an interesting
use-case of augmented multi-view learning.


title: Multiscale Partition of Unity

abstract:
  We introduce a new Partition of Unity Method for the numerical homogenization
of elliptic partial differential equations with arbitrarily rough coefficients.
We do not restrict to a particular ansatz space or the existence of a finite
element mesh. The method modifies a given partition of unity such that optimal
convergence is achieved independent of oscillation or discontinuities of the
diffusion coefficient. The modification is based on an orthogonal decomposition
of the solution space while preserving the partition of unity property. This
precomputation involves the solution of independent problems on local
subdomains of selectable size. We deduce quantitative error estimates for the
method that account for the chosen amount of localization. Numerical
experiments illustrate the high approximation properties even for 'cheap'
parameter choices.


title: Quantum time of arrival distribution in a simple lattice model

abstract:
  Imagine an experiment where a quantum particle inside a box is released at
some time in some initial state. A detector is placed at a fixed location
inside the box and its clicking signifies arrival of the particle at the
detector. What is the \emph{time of arrival} (TOA) of the particle at the
detector ? Within the paradigm of the measurement postulate of quantum
mechanics, one can use the idea of projective measurements to define the TOA.
We consider the setup where a detector keeps making instantaneous measurements
at regular finite time intervals {\emph{till}} it detects the particle at some
time $t$, which is defined as the TOA. This is a stochastic variable and, for a
simple lattice model of a free particle in a one-dimensional box, we find
interesting features such as power-law tails in its distribution and in the
probability of survival (non-detection). We propose a perturbative
calculational approach which yields results that compare very well with exact
numerics.


title: Black Hole X-ray Transients: The Formation Puzzle

abstract:
  There are 19 confirmed BH binaries in the Galaxy. 16 of them are X-ray
transients hosting a ~5-15 Msun BH and a Roche-lobe overflowing low-mass
companion. Companion masses are found mostly in 0.1-1 Msun mass range with peak
at 0.6 Msun. The formation of these systems is believed to involve a common
envelope phase, initiated by a BH progenitor, expected to be a massive star >20
Msun. It was realized that it may be very problematic for a low-mass companion
to eject a massive envelope of the black hole progenitor. It invoked
suggestions that an intermediate-mass companion ejects the envelope, and then
is shredded by the Roche-lobe overflow to its current low-mass. But this
creates another issue; a temperature mismatch between hot models and the
observed cool low-mass donors. Finally, the main driver of Roche-lobe overflow
that is believed to be magnetic braking does not seem to follow any
theoretically calculated models. Number of ideas were put forward to explain
various parts of this conundrum; pre-main sequence donor nature, alternative
approach to magnetic braking and common envelope energy was revisited. We test
various proposals and models to show that no overall solution exists so far. We
argue that common envelope physics is not crucial in the understanding BH
transient physical properties, but may affect significantly their formation
rates. Our failure most likely indicates that either the current evolutionary
models for low-mass stars and magnetic braking are not realistic or that the
intrinsic population of BH transients is quite different from the observed one.


title:
Cation-ordered A$'_{1/2}$A$''_{1/2}$B$_2$X$_4$ magnetic spinels as
  magnetoelectrics

abstract:
  We show that 1:1 ordering of A$'$ and A$''$ cations in
A$'_{1/2}$A$''_{1/2}$B$_2$X$_4$ magnetic spinels results in appearance of
magnetoelectric properties. Possible value of magnetically induced electric
polarization is calculated using the recently proposed microscopic model, which
takes into account spin-dependent electric dipole moments of magnetic ions
located in noncentrosymmetric crystallographic positions. We build
phenomenological models of magnetic phase transitions in cation-ordered
spinels, which describe ferromagnetic and antiferromagnetic ordering patterns
of B cation spins, and calculate the respective magnetoelectric responses. We
find that magnetoelectric coefficients diverge at ferromagnetic or weak
ferromagnetic phase transitions in ordered spinels.


title: Strain Engineering of Selective Chemical Adsorption on Monolayer MoS_2

abstract:
  Nanomaterials are prone to influence by chemical adsorption because of their
large surface to volume ratios. This enables sensitive detection of adsorbed
chemical species which, in turn, can tune the property of the host material.
Recent studies discovered that single and multilayer molybdenum disulfide
(MoS_2) films are ultra sensitive to several important environmental molecules.
Here we report new findings from ab initio calculations that reveal
substantially enhanced adsorption of NO and NH3 on strained monolyaer MoS2 with
significant impact on the properties of the adsorbates and MoS2 layer. The
magnetic moment of adsobed NO can be turned between 0 and 1 uB, strain also
induces an electronic phase transition between half-metal and metal. Adsorption
of NH3 weakens the MoS2 layer considerably, which explains the large discrepacy
between the experimentally measured strength and breaking strain of MoS2 film
from previous theoretical predictions. On the other hand, adsorption of NO2, CO
and CO2 is insensitive to the strain condition in the MoS2 layer. This
contrasting behavior allows sensitive strain engineering of selective chemical
adsorption on MoS2 with effective tuning of mechanical, electronic and magnetic
properties. These result suggest new design strategies for constructing MoS2
based ultrahigh sensitivity nanoscale sensor and electromechanical devices.


title:
Next-to-leading order QCD corrections to di-photon production in
  association with up to three jets at the Large Hadron Collider

abstract:
  We present the computation of next-to-leading order (NLO) QCD corrections to
di-photon production in association with two or three hard jets in pp
collisions at a center-of-mass energy of 8 TeV. The inclusion of NLO
corrections is shown to substantially reduce the theoretical uncertainties
estimated from scale variations on total cross section predictions. We study a
range of differential distributions relevant for phenomenological studies of
photon pair production in association with jets at the LHC. Using an efficient
computational set-up we performed a detailed study of uncertainties due to
parton distribution functions. The computation of the virtual corrections is
performed using new features of the C++ library NJET.


title:
Stellar Granulation as the Source of High-Frequency Flicker in Kepler
  Light Curves

abstract:
  A large fraction of cool, low-mass stars exhibit brightness fluctuations that
arise from a combination of convective granulation, acoustic oscillations,
magnetic activity, and stellar rotation. Much of the short-timescale
variability takes the form of stochastic noise, whose presence may limit the
progress of extrasolar planet detection and characterization. In order to lay
the groundwork for extracting useful information from these quasi-random
signals, we focus on the origin of the granulation-driven component of the
variability. We apply existing theoretical scaling relations to predict the
star-integrated variability amplitudes for 508 stars with photometric light
curves measured by the Kepler mission. We also derive an empirical correction
factor that aims to account for the suppression of convection in F-dwarf stars
with magnetic activity and shallow convection zones. So that we can make
predictions of specific observational quantities, we performed Monte Carlo
simulations of granulation light curves using a Lorentzian power spectrum.
These simulations allowed us to reproduce the so-called "flicker floor" (i.e.,
a lower bound in the relationship between the full light-curve range and power
in short-timescale fluctuations) that was found in the Kepler data. The Monte
Carlo model also enabled us to convert the modeled fluctuation variance into a
flicker amplitude directly comparable with observations. When the magnetic
suppression factor described above is applied, the model reproduces the
observed correlation between stellar surface gravity and flicker amplitude.
Observationally validated models like these provide new and complementary
evidence for a possible impact of magnetic activity on the properties of
near-surface convection.


title: Exciton spin dynamics of colloidal CdTe nanocrystals in magnetic field

abstract:
  The recombination and spin dynamics of excitons in colloidal CdTe
nanocrystals (NCs) are studied by time-resolved photoluminescence in high
magnetic fields up to 15 T and at cryogenic temperatures. The recombination
decay shows a nonexponential temporal behavior, with the longest component
corresponding to the dark excitons having 260 ns decay time at zero magnetic
field and 4.2 K temperature. This long component shortens to 150 ns at 15 T due
to the magnetic-field-induced mixing of the bright and dark exciton states. The
spin dynamics, assessed through the evolution of the magnetic-field-induced
circular polarization degree of the photoluminescence, has a fast component
shorter than 1 ns related to the bright excitons and a slow component of 5-10
ns associated with the dark excitons. The latter shortens with increasing
magnetic field, which is characteristic for a phonon-assisted spin relaxation
mechanism. The relatively low saturation level of the associated
magnetic-field-induced circular polarization degree of -30 % is explained by a
model that suggests the CdTe NCs to constitute an ensemble of prolate and
oblate NCs, both having a structural quantization axis. The exciton g-factor of
2.4-2.9 evaluated from fitting the experimental data in the frame of the
suggested approach is in good agreement with the expected value for the dark
excitons in CdTe NCs.


title:
The microscopic basis for phase-sensitive experiments for determination
  of the order parameter symmetry in Fe-based superconductors

abstract:
  We present a microscopic theory of dc Josephson current, based on the
construction of a coherent temperature Green function in the tight-binding
approximation, in junctions with multiband superconductors. This theory is
applied to the junctions with multiband Fe-based superconductors (FeBS)
described by anisotropic s-wave order parameter symmetries, which probably
realized in FeBS. We confirm microscopically the previously suggested crucial
experiment for determination of the type of the order parameter symmetry in
FeBS.


title: Peierls substitution for magnetic Bloch bands

abstract:
  We consider the Schr\"odinger operator in two dimensions with a periodic
potential and a strong constant magnetic field perturbed by slowly varying
non-periodic scalar and vector potentials, $\phi(\epsilon x)$ and $A(\epsilon
x)$, for $\epsilon\ll 1$. For each isolated family of magnetic Bloch bands we
derive an effective Hamiltonian that is unitarily equivalent to the restriction
of the Schr\"odinger operator to a corresponding almost invariant subspace. At
leading order, our effective Hamiltonian can be interpreted as the Peierls
substitution Hamiltonian widely used in physics for non-magnetic Bloch bands.
However, while for non-magnetic Bloch bands the corresponding result is well
understood, for magnetic Bloch bands it is not clear how to even define a
Peierls substitution Hamiltonian beyond a formal expression. The source of the
difficulty is a topological obstruction: magnetic Bloch bundles are generically
not trivializable. As a consequence, Peierls substitution Hamiltonians for
magnetic Bloch bands turn out to be pseudodifferential operators acting on
sections of non-trivial vector bundles over a two-torus, the reduced Brillouin
zone. Part of our contribution is the construction of a suitable Weyl calculus
for such pseudos. As an application of our results we construct a new family of
canonical one-band Hamiltonians $H^B_{\theta,q}$ for magnetic Bloch bands with
Chern number $\theta\in \mathbb{Z}$ that generalizes the Hofstadter model
$H^B_{\rm Hof} = H^B_{0,1}$ for a single non-magnetic Bloch band. It turns out
that $H^B_{\theta,q}$ is isospectral to $H^{q^2B}_{\rm Hof}$ for any $\theta$
and all spectra agree with the Hofstadter spectrum depicted in his famous black
and white butterfly. However, the resulting Chern numbers of subbands,
corresponding to Hall conductivities, depend on $\theta$ and $q$, and thus the
models lead to different colored butterflies.


title: Strictly convergent analytic structures

abstract:
  We give conclusive answers to some questions about definability in analytic
languages that arose shortly after the work by Denef and van den Dries, [DD],
on $p$-adic subanalytic sets, and we continue the study of non-archimedean
fields with analytic structure of [LR3], [CLR1] and [CL1]. We show that the
language $L_K$ consisting of the language of valued fields together with all
strictly convergent power series over a complete, rank one valued field $K$ can
be expanded, in a definitial way, to a larger language corresponding to an
analytic structure (with separated power series) from [CL1], hence inheriting
all properties from loc. cit., including geometric properties for the definable
sets like certain forms of quantifier elimination. Our expansion comes from
adding specific, existentially definable functions, which are solutions of
certain henselian systems of equations. Moreover, we show that, even when $K$
is algebraically closed, one does not have quantifier elimination in $L_K$
itself, and hence, passing to expansions is unavoidable in general. We pursue
this study in the wider generality of extending non-separated power series
rings to separated ones, and give new examples, in particular of the analytic
structure over $\mathbb{Z}[[t]]$ that can be interpreted and understood now in
all complete valued fields. In a separate direction, we show in rather large
generality that Weierstrass preparation implies Weierstrass division.


title: Cooperative Lamb shift in a quantum emitter array

abstract:
  Whenever several quantum light emitters are brought in proximity with one
another, their interaction with common electromagnetic fields couples them,
giving rise to cooperative shifts in their resonance frequency. Such collective
line shifts are central to modern atomic physics, being closely related to
superradiance on one hand and the Lamb shift on the other. Although collective
shifts have been theoretically predicted more than fifty years ago, the effect
has not been observed yet in a controllable system of a few isolated emitters.
Here, we report a direct spectroscopic observation of the cooperative shift of
an optical electric dipole transition in a system of up to eight Sr ions
suspended in a Paul trap. We study collective resonance shift in the previously
unexplored regime of far-field coupling, and provide the first observation of
cooperative effects in an array of quantum emitters. These results pave the way
towards experimental exploration of cooperative emission phenomena in
mesoscopic systems.


title: Assessment of Point Process Models for Earthquake Forecasting

abstract:
  Models for forecasting earthquakes are currently tested prospectively in
well-organized testing centers, using data collected after the models and their
parameters are completely specified. The extent to which these models agree
with the data is typically assessed using a variety of numerical tests, which
unfortunately have low power and may be misleading for model comparison
purposes. Promising alternatives exist, especially residual methods such as
super-thinning and Voronoi residuals. This article reviews some of these tests
and residual methods for determining the goodness of fit of earthquake
forecasting models.


title: Magnon condensation with finite degeneracy on the triangular lattice

abstract:
  We study the spin 1/2 triangular-lattice $J_1$-$J_2$-$J_3$ antiferromagnet
close to the saturation field using the dilute Bose gas theory, where the
magnetic structure is determined by the condensation of magnons. We focus on
the case of ferromagnetic $J_1$ and antiferromagnetic $J_2,J_3$, that is
particularly rich because frustration effects allow the single-magnon energy
dispersion to have six-fold degenerate minima at incommensurate momenta. Our
calculation also includes an interlayer coupling $J_0$, which covers both
antiferromagnetic and ferromagnetic cases including negligibly small regime
(two-dimensional case). Besides the spiral and fan phases, we find a new
double-$q$ phase (superposition of two modes), dubbed "${\bf Q}_0$-${\bf Q}_1$"
(or simply "01") phase, that enjoys a new type of multiferroic character.
Certain phase boundaries have a singular $J_0$ dependence for $J_0\to 0$,
implying that even a very small interlayer coupling drastically changes the
ground state. A mechanism for this singularity is presented. Moreover, in some
regions of the parameter space, we show that a dilute gas of magnons can not be
stable, and phase separation (corresponding to a magnetization jump) is
expected. In the $J_1$-$J_2$ model ($J_3=0$), formation of two-magnon bound
states is observed, which can lead to a quadrupolar (spin-nematic) ordered
phase. Exact diagonalization analysis is also applied to the search of bound
states.


title: Measuring voting power in convex policy spaces

abstract:
  Classical power index analysis considers the individual's ability to
influence the aggregated group decision by changing its own vote, where all
decisions and votes are assumed to be binary. In many practical applications we
have more options than either "yes" or "no". Here we generalize three important
power indices to continuous convex policy spaces. This allows the analysis of a
collection of economic problems like e.g. tax rates or spending that otherwise
would not be covered in binary models.


title: On the dynamic width of the 3-colorability problem

abstract:
  A graph $G$ is 3-colorable if and only if it maps homomorphically to the
complete 3-vertex graph $K_3$. The last condition can be checked by a
$k$-consistency algorithm where the parameter $k$ has to be chosen large
enough, dependent on $G$. Let $W(G)$ denote the minimum $k$ sufficient for this
purpose. For a non-3-colorable graph $G$, $W(G)$ is equal to the minimum $k$
such that $G$ can be distinguished from $K_3$ in the $k$-variable
existential-positive first-order logic. We define the dynamic width of the
3-colorability problem as the function $W(n)=\max_G W(G)$, where the maximum is
taken over all non-3-colorable $G$ with $n$ vertices.
  The assumption $\mathrm{NP}\ne\mathrm{P}$ implies that $W(n)$ is unbounded.
Indeed, a lower bound $W(n)=\Omega(\log\log n/\log\log\log n)$ follows
unconditionally from the work of Nesetril and Zhu on bounded treewidth duality.
The Exponential Time Hypothesis implies a much stronger bound
$W(n)=\Omega(n/\log n)$ and indeed we unconditionally prove that
$W(n)=\Omega(n)$. In fact, an even stronger statement is true: A first-order
sentence distinguishing any 3-colorable graph on $n$ vertices from any
non-3-colorable graph on $n$ vertices must have $\Omega(n)$ variables.
  On the other hand, we observe that $W(G)\le 3\,\alpha(G)+1$ and $W(G)\le
n-\alpha(G)+1$ for every non-3-colorable graph $G$ with $n$ vertices, where
$\alpha(G)$ denotes the independence number of $G$. This implies that
$W(n)\le\frac34\,n+1$, improving on the trivial upper bound $W(n)\le n$.
  We also show that $W(G)>\frac1{16}\, g(G)$ for every non-3-colorable graph
$G$, where $g(G)$ denotes the girth of $G$.
  Finally, we consider the function $W(n)$ over planar graphs and prove that
$W(n)=\Theta(\sqrt n)$ in the case.


title:
Dual-Branch MRC Receivers under Spatial Interference Correlation and
  Nakagami Fading

abstract:
  Despite being ubiquitous in practice, the performance of maximal-ratio
combining (MRC) in the presence of interference is not well understood. Because
the interference received at each antenna originates from the same set of
interferers, but partially de-correlates over the fading channel, it possesses
a complex correlation structure. This work develops a realistic analytic model
that accurately accounts for the interference correlation using stochastic
geometry. Modeling interference by a Poisson shot noise process with
independent Nakagami fading, we derive the link success probability for
dual-branch interference-aware MRC. Using this result, we show that the common
assumption that all receive antennas experience equal interference power
underestimates the true performance, although this gap rapidly decays with
increasing the Nakagami parameter $m_{\text{I}}$ of the interfering links. In
contrast, ignoring interference correlation leads to a highly optimistic
performance estimate for MRC, especially for large $m_{\text{I}}$. In the low
outage probability regime, our success probability expression can be
considerably simplified. Observations following from the analysis include: (i)
for small path loss exponents, MRC and minimum mean square error combining
exhibit similar performance, and (ii) the gains of MRC over selection combining
are smaller in the interference-limited case than in the well-studied
noise-limited case.


title:
Alleviating a form of electric vehicle range anxiety through On-Demand
  vehicle access

abstract:
  On-demand vehicle access is a method that can be used to reduce types of
range anxiety problems related to planned travel for electric vehicle owners.
Using ideas from elementary queueing theory, basic QoS metrics are defined to
dimension a shared fleet to ensure high levels of vehicle access. Using
mobility data from Ireland, it is argued that the potential cost of such a
system is very low.


title: Generic Deep Networks with Wavelet Scattering

abstract:
  We introduce a two-layer wavelet scattering network, for object
classification. This scattering transform computes a spatial wavelet transform
on the first layer and a new joint wavelet transform along spatial, angular and
scale variables in the second layer. Numerical experiments demonstrate that
this two layer convolution network, which involves no learning and no max
pooling, performs efficiently on complex image data sets such as CalTech, with
structural objects variability and clutter. It opens the possibility to
simplify deep neural network learning by initializing the first layers with
wavelet filters.


title: Developing a model of evacuation after an earthquake in Lebanon

abstract:
  This article describes the development of an agent-based model (AMEL,
Agent-based Model for Earthquake evacuation in Lebanon) that aims at simulating
the movement of pedestrians shortly after an earthquake. The GAMA platform was
chosen to implement the model. AMEL is applied to a real case study, a district
of the city of Beirut, Lebanon, which potentially could be stricken by a M7
earthquake. The objective of the model is to reproduce real life mobility
behaviours that have been gathered through a survey in Beirut and to test
different future scenarios, which may help the local authorities to target
information campaigns.


title:
Un theoreme de semi-continuite pour l'entropie des applications
  meromorphes

abstract:
  We prove a theorem of uppersemicontinuity for the metric entropy of
meromorphic maps.


title: A diophantine equation for sums of consecutive like powers

abstract:
  We show that the diophantine equation $n^\ell+(n+1)^\ell + ...+
(n+k)^\ell=(n+k+1)^\ell+ ...+ (n+2k)^\ell$ has no solutions in positive
integers $k,n \ge 1$ for all $\ell \ge 3$.


title: Does Planck really rule out monomial inflation?

abstract:
  We consider the modifications of monomial chaotic inflation models due to
radiative corrections induced by inflaton couplings to bosons and/or fermions
necessary for reheating. To the lowest order, ignoring gravitational
corrections and treating the inflaton as a classical background field, they are
of the Coleman-Weinberg type and parametrized by the renormalization scale
$\mu$. In cosmology, there are not enough measurements to fix $\mu$ so that we
end up with a family of models, each having a slightly different slope of the
potential. We demonstrate by explicit calculation that within the family of
chaotic $\phi^2$ models, some may be ruled out by Planck whereas some remain
perfectly viable. In contrast, radiative corrections do not seem to help
chaotic $\phi^{4}$ models to meet the Planck constraints.


title: The theory of pulsar wind nebulae

abstract:
  I review the current status of our theoretical understanding of Pulsar Winds
and associated nebulae (PWNe). In recent years, axisymmetric models of pulsar
winds with a latitude dependent energy flux have proved very successful at
explaining the morphology of PWNe as seen in the X-rays. This success has
prompted developments aimed at using multi-wavelength observations of these
nebulae as a diagnostics of the hidden physics of the pulsar wind and of the
mechanism(s) through which particles are accelerated in these sources. I will
discuss these most recent developments in terms of the information that we
infer from detailed comparison of simulated non-thermal emission with current
observations.


title: Adaptive Seeding for Gaussian Mixture Models

abstract:
  We present new initialization methods for the expectation-maximization
algorithm for multivariate Gaussian mixture models. Our methods are adaptions
of the well-known $K$-means++ initialization and the Gonzalez algorithm.
Thereby we aim to close the gap between simple random, e.g. uniform, and
complex methods, that crucially depend on the right choice of hyperparameters.
Our extensive experiments indicate the usefulness of our methods compared to
common techniques and methods, which e.g. apply the original $K$-means++ and
Gonzalez directly, with respect to artificial as well as real-world data sets.


title: Spectral asymptotics of a broken delta interaction

abstract:
  This paper is concerned with the spectral analysis of a Hamiltonian with a
$\delta$-interaction supported along a broken line with angle $\theta$. The
bound states with energy slightly below the threshold of the essential spectrum
are estimated in the semiclassical regime $\theta\to 0$.


title:
Non-equilibrium scale invariance and shortcuts to adiabaticity in a
  one-dimensional Bose gas

abstract:
  We present experimental evidence for scale invariant behaviour of the
excitation spectrum in phase-fluctuating quasi-1d Bose gases after a rapid
change of the external trapping potential. Probing density correlations in free
expansion, we find that the temperature of an initial thermal state scales with
the spatial extension of the cloud as predicted by a model based on adiabatic
rescaling of initial eigenmodes with conserved quasiparticle occupation
numbers. Based on this result, we demonstrate that shortcuts to adiabaticity
for the rapid expansion or compression of the gas do not induce additional
heating.


title:
Renormalizability of the nuclear many-body problem with the Skyrme
  interaction beyond mean field

abstract:
  Phenomenological effective interactions like Skyrme forces are currently used
in mean--field calculations in nuclear physics. Mean--field models have strong
analogies with the first order of the perturbative many--body problem and the
currently used effective interactions are adjusted at the mean--field level. In
this work, we analyze the renormalizability of the nuclear many--body problem
in the case where the effective Skyrme interaction is employed in its standard
form and the perturbative problem is solved up to second order. We focus on
symmetric nuclear matter and its equation of state, which can be calculated
analytically at this order. It is shown that only by applying specific density
dependence and constraints to the interaction parameters could
renormalizability be guaranteed in principle. This indicates that the standard
Skyrme interaction does not in general lead to a renormalizable theory. For
achieving renormalizability, other terms should be added to the interaction and
employed perturbatively only at first order.


title: The performance of the LHCf detector for hadronic showers

abstract:
  The Large Hadron Collider forward (LHCf) experiment has been designed to use
the LHC to benchmark the hadronic interaction models used in cosmic-ray
physics. The LHCf experiment measures neutral particles emitted in the very
forward region of LHC collisions. In this paper, the performances of the LHCf
detectors for hadronic showers was studied with MC simulations and beam tests.
The detection efficiency for neutrons is from 60% to 70% above 500 GeV. The
energy resolutions are about 40% and the position resolution is 0.1 to 1.3mm
depend on the incident energy for neutrons. The energy scale determined by the
MC simulations and the validity of the MC simulations were examined using 350
GeV proton beams at the CERN-SPS.


title: Automated Verification of Quantum Protocols by Equivalence Checking

abstract:
  In this paper we introduce a technique and a tool for formal verification of
various quantum information processing protocols. The tool uses stabilizer
formalism and is capable of representing concurrent quantum protocol, thus is
more expressive than quantum circuits. We also report on experimental results
of using our Quantum Equivalence Checker (QEC) to analyse a range of quantum
information processing protocols.


title:
Proceedings of the Fourth International Workshop on Domain-Specific
  Languages and Models for Robotic Systems (DSLRob 2013)

abstract:
  The Fourth International Workshop on Domain-Specific Languages and Models for
Robotic Systems (DSLRob'13) was held in conjunction with the 2013 IEEE/RSJ
International Conference on Intelligent Robots and Systems (IROS 2013),
November 2013 in Tokyo, Japan.
  The main topics of the workshop were Domain-Specific Languages (DSLs) and
Model-driven Software Development (MDSD) for robotics. A domain-specific
language is a programming language dedicated to a particular problem domain
that offers specific notations and abstractions that increase programmer
productivity within that domain. Model-driven software development offers a
high-level way for domain users to specify the functionality of their system at
the right level of abstraction. DSLs and models have historically been used for
programming complex systems. However recently they have garnered interest as a
separate field of study. Robotic systems blend hardware and software in a
holistic way that intrinsically raises many crosscutting concerns (concurrency,
uncertainty, time constraints, ...), for which reason, traditional
general-purpose languages often lead to a poor fit between the language
features and the implementation requirements. DSLs and models offer a powerful,
systematic way to overcome this problem, enabling the programmer to quickly and
precisely implement novel software solutions to complex problems within the
robotics domain.


title: An online version of Rota's basis conjecture

abstract:
  Rota's basis conjecture states that in any square array of vectors whose rows
are bases of a fixed vector space the vectors can be rearranged within their
rows in such a way that afterwards not only the rows are bases, but also the
columns. We discuss an online version of this conjecture, in which the
permutation used for rearranging the vectors in a given row must be determined
without knowledge of the vectors further down the array. The paper contains
surprises both for those who believe this online basis conjecture at first
glance, and for those who disbelieve it.


title: Fluctuating interfaces subject to stochastic resetting

abstract:
  We study one-dimensional fluctuating interfaces of length $L$ where the
interface stochastically resets to a fixed initial profile at a constant rate
$r$. For finite $r$ in the limit $L \to \infty$, the system settles into a
nonequilibrium stationary state with non-Gaussian interface fluctuations, which
we characterize analytically for the Kardar-Parisi-Zhang and Edwards-Wilkinson
universality class. Our results are corroborated by numerical simulations. We
also discuss the generality of our results for a fluctuating interface in a
generic universality class.


title:
Critical values of Rankin-Selberg L-functions for GL(n) x GL(n-1) and
  the symmetric cube L-functions for GL(2)

abstract:
  In a previous article we had proved an algebraicity result for the central
critical value for L-functions for GL(n) x GL(n-1) over Q assuming the validity
of a nonvanishing hypothesis involving archimedean integrals. The purpose of
this article is to generalize that result for all critical values for
L-functions for GL(n) x GL(n-1) over any number field F. Binyong Sun has
recently proved that nonvanishing hypothesis and so the results of this article
are unconditional. Using such results for the case of GL(3) x GL(2), new
unconditional algebraicity results for the special values of symmetric cube
L-functions for GL(2) over F have been proved.


title: A Radio Determination of the Time of the New Moon

abstract:
  The detection of the New Moon at sunset is of importance to communities based
on the lunar calendar. This is traditionally undertaken with visual
observations. We propose a radio method which allows a higher visibility of the
Moon relative to the Sun and consequently gives us the ability to detect the
Moon much closer to the Sun than is the case of visual observation. We first
compare the relative brightness of the Moon and Sun over a range of possible
frequencies and find the range 5--100\,GHz to be suitable. The next
consideration is the atmospheric absorption/emission due to water vapour and
oxygen as a function of frequency. This is particularly important since the
relevant observations are near the horizon. We show that a frequency of $\sim
10$ GHz is optimal for this programme. We have designed and constructed a
telescope with a FWHM resolution of 0$^\circ{}\!\!$.6 and low sidelobes to
demonstrate the potential of this approach. At the time of the 21 May 2012 New
Moon the Sun/Moon brightness temperature ratio was $72.7 \pm 2.2$ in agreement
with predictions from the literature when combined with the observed sunspot
numbers for the day. The Moon would have been readily detectable at $\sim
2^{\circ}$ from the Sun. Our observations at 16\,hr\,36\,min UT indicated that
the Moon would have been at closest approach to the Sun 16\,hr\,25\,min
earlier; this was the annular solar eclipse of 00\,hr\,00\,min\,UT on 21 May
2012.


title: A study of convolution models for background correction of BeadArrays

abstract:
  The RMA, since its introduction in \cite{Iri03a, Iri03b, Iri06}, has gained
popularity among bioinformaticians. It has evolved from the exponential-normal
convolution to the gamma-normal convolution, from single to two channels and
from the Affymetrix to the Illumina platform.
  The Illumina design has provided two probe types: the regular and the control
probes. This design is very suitable for studying the probability distribution
of both and one can apply the convolution model to compute the true intensity
estimator. The availability of benchmarking data set at Illumina platform, the
{\it Illumina spike-in}, helps researchers to evaluate their proposed method
for Illumina BeadArrays.
  In this paper, we study the existing convolution models for background
correction of Illumina BeadArrays in the literature and give a new estimator
for the true intensity, where the intensity value is exponentially or gamma
distributed and the noise has lognormal distribution. We compare the
performance of the models on the Illumina spike-in data set, based on various
criteria, for example, root and mean square error, $L_{1}$ error,
Kullback-Leibler coefficient, and some adapted criteria from Affycomp
\cite{Cop04}. We then provide a simulation study to measure the consistency of
the error of background correction and the parametrization. We also study the
performance of all models on the FFPE data set.
  Our study shows that our GLNn model is the optimal one for the benchmarking
data set with benchmarking criteria, while the gamma-normal model has the best
performance for the benchmarking data set with simulation criteria. At the
public data set of FFPE, the gamma-normal and the exponential-gamma models with
MLE cannot be used and our proposed models ELN and GLN have the best
performance, showing a moderate error in background correction and in the
parametrization.


title:
A diagrammatic categorification of the affine q-Schur algebra S(n,n) for
  n > 2

abstract:
  This is a follow-up to the paper in which we categorified the affine quantum
Schur algebra S(n,r) for 2 < r < n, using a quotient of Khovanov and Lauda's
categorification of the affine quantum sl_n. In this paper we categorify S(n,n)
for n > 2, using an extension of the aforementioned quotient.