title:
On the partial condition numbers for the indefinite least squares
  problem

abstract:
  The condition number of a linear function of the indefinite least squares
solution is called the partial condition number for the indefinite least
squares problem. In this paper, based on a new and very general condition
number which can be called the unified condition number, the expression of the
partial unified condition number is first presented when the data space is
measured by the general weighted product norm. Then, by setting the specific
norms and weight parameters, we obtain the expressions of the partial normwise,
mixed and componentwise condition numbers. Moreover, the corresponding
structured partial condition numbers are also taken into consideration when the
problem is structured, whose expressions are given. Considering the connections
between the indefinite and total least squares problems, we derive the
(structured) partial condition numbers for the latter, which generalize the
ones in the literature. To estimate these condition numbers effectively and
reliably, the probabilistic spectral norm estimator and the small-sample
statistical condition estimation method are applied and three related
algorithms are devised. Finally, the obtained results are illustrated by
numerical experiments.


title:
Operator description for thermal quantum field theories on an arbitrary
  path in the real time formalism

abstract:
  We develop an operator description, much like thermofield dynamics, for
quantum field theories on a real time path with an arbitrary parameter
$\sigma\,(0\leq\sigma\leq\beta)$. We point out new features which arise when
$\sigma\neq \frac{\beta}{2}$ in that the Hilbert space develops a natural,
modified inner product different from the standard Dirac inner product. We
construct the Bogoliubov transformation which connects the doubled vacuum state
at zero temperature to the thermal vacuum in this case. We obtain the thermal
Green's function (propagator) for the real massive Klein-Gordon theory as an
expectation value in this thermal vacuum (with a modified inner product). The
factorization of the thermal Green's function follows from this analysis. We
also discuss, in the main text as well as in two appendices, various other
interesting features which arise in such a description.


title: Digital Stylometry: Linking Profiles Across Social Networks

abstract:
  There is an ever growing number of users with accounts on multiple social
media and networking sites. Consequently, there is increasing interest in
matching user accounts and profiles across different social networks in order
to create aggregate profiles of users. In this paper, we present models for
Digital Stylometry, which is a method for matching users through stylometry
inspired techniques. We experimented with linguistic, temporal, and combined
temporal-linguistic models for matching user accounts, using standard and novel
techniques. Using publicly available data, our best model, a combined
temporal-linguistic one, was able to correctly match the accounts of 31% of
5,612 distinct users across Twitter and Facebook.


title:
Evolution of the thermodynamic properties and inelastic neutron
  scattering intensities for spin-1/2 antiferromagnetic quantum rings

abstract:
  This study examines the increasing complexity in the magnetic properties of
small $n$ = 3, 4, 5, 6 spin-1/2 quantum rings. Using an exact diagonalization
of the isotropic Heisenberg Hamiltonian with nearest and next-nearest neighbor
interactions, the energy eigenstates, magnetic specific heat capacity, magnetic
susceptibility, and inelastic neutron scattering structure factors are
determined for variable next-nearest neighbor interactions. Here, it is shown
that the presence of a complex spin-mixing, multiple ground states, and
non-zero ground states greatly complicate the spin Hamiltonian. Overall, the
energy eigenstates and structure factor intensities are presented in closed
form, while the thermodynamic properties detail the effect of a crossing
interaction in the rings. The goal of this work is to provide insight into the
evolution of the magnetic properties and spin excitations within these systems.


title: The Zak transform on strongly proper $G$-spaces and its applications

abstract:
  The Zak transform on $\mathbb{R}^d$ is an important tool in condensed matter
physics, signal processing, time-frequency analysis, and harmonic analysis in
general. This article introduces a generalization of the Zak transform to a
class of locally compact $G$-spaces, where $G$ is either a locally compact
abelian or a second countable unimodular type I group. This framework unifies
previously proposed generalizations of the Zak transform. It is shown that the
Zak transform has invariance properties analog to the classic case and is a
Hilbert space isomorphism between the space of $L^2$-functions and a direct
integral of Hilbert spaces that is explicitly determined via a Weil formula for
$G$-spaces and a Poisson summation formula for compact subgroups. Some
applications in physics are outlined.


title: Counterexamples to the Complement Problem

abstract:
  We provide explicit counterexamples to the so-called Complement Problem in
every dimension $n\geq3$, i.e. pairs of non-isomorphic irreducible
hypersurfaces $H_1, H_2\subset\mathbb{C}^{n}$ whose complements
$\mathbb{C}^{n}\setminus H_1$ and $\mathbb{C}^{n}\setminus H_2$ are isomorphic.
Since we can arrange that one of the hypersurfaces is singular whereas the
other is smooth, we also have counterexamples in the analytic setting.


title:
Twisted superfluid phase in the extended one-dimensional Bose-Hubbard
  model

abstract:
  In one-dimensional systems a twisted superfluid phase is found which is
induced by a spontaneous breaking of the time-reversal symmetry. Using the
density-matrix renormalization group allows us to show that the excitation
energy gap closes exponentially causing a quasi-degenerate ground state. The
two degenerate ground states are connected by the time-reversal symmetry which
manifests itself in an alternating complex phase of the long-range correlation
function. The quantum phase transition to the twisted superfluid is driven by
pair tunneling processes in an extended Bose-Hubbard model. The phase
boundaries of several other phases are discussed including a supersolid, a pair
superfluid, and a pair supersolid phase as well as a highly unconventional Mott
insulator with a degenerate ground state and a staggered pair correlation
function.


title: Mapping chiral symmetry breaking in the excited baryon spectrum

abstract:
  We study the conjectured "Insensitivity to Chiral Symmetry Breaking" in the
highly excited light baryon spectrum. While the experimental spectrum is being
measured at JLab and CBELSA/TAPS, this insensitivity remains to be computed
theoretically in detail. As the only existing option to have both confinement,
highly excited states and chiral symmetry, we adopt the truncated Coulomb gauge
formulation of QCD, considering a linearly confining Coulomb term. Adopting a
systematic and numerically intensive variational treatment up to 12 harmonic
oscillator shells we are able to access several angular and radial excitations.
We compute both the excited spectra of $I=1/2$ and $I=3/2$ baryons, up to large
spin $J=13/2$, and study in detail the proposed chiral multiplets. While the
static-light and light-light spectra clearly show chiral symmetry restoration
high in the spectrum, the realization of chiral symmetry is more complicated in
the baryon spectrum than earlier expected.


title:
Siamese convolutional networks based on phonetic features for cognate
  identification

abstract:
  In this paper, we explore the use of convolutional networks (ConvNets) for
the purpose of cognate identification. We compare our architecture with binary
classifiers based on string similarity measures on different language families.
Our experiments show that convolutional networks achieve competitive results
across concepts and across language families at the task of cognate
identification.


title: Early Stopping for Interleaver Recovering of Turbo Codes

abstract:
  Parameter recovering of channel codes is important in applications such as
cognitive radio. The main task for that of a turbo code is to recover the
interleaver. The existing optimal algorithm recovers interleaver parameters
incrementally one by one. This algorithm continues till the end even if it has
failed in the halfway. And there would be lots of wasted computation, as well
as incorrectly recovered parameters that will badly deteriorate turbo decoding
performance. To address such drawbacks, this paper proposes an early stopping
method for the algorithm. Thresholds needed for the method are set through
theoretical analysis. Simulations show that the proposed method is able to stop
the algorithm in time after it has failed, while no significant degradation in
the correct recovering probability is observed.


title: Optical teardown of a Kindle Paperwhite display by OCT

abstract:
  An optical teardown, or reverse engineering, of an Amazon Kindle Paperwhite
electrophoretic display was performed by Optical Coherence Tomography at 1060
nm. The display incorporates an optical diffuser, lightguide and scattering
layers for white light illumination, capacitive touch sensing, and an
electrophoretic display. All these layers can be imaged by OCT as well as the
thin film transistor array on the back side for driving the pixels. Phase
sensitive OCT is used to measure motion of the pigment particles as the display
changes between black and white.


title:
Classical Monte Carlo study for antiferro quadrupole orders in a diamond
  lattice

abstract:
  We investigate antiferro quadrupole orders in a diamond lattice under
magnetic fields by Monte Carlo simulations for two types of classical effective
models. One is an XY model with Z_3 anisotropy, and the other is a
two-component phi^4 model with a third-order anisotropy. We confirm that the
universality class of the zero-field transition is that for the
three-dimensional XY model. Magnetic field corresponds to a Z_3 field in the
effective model, and under this field, we find that collinear and canted
antiferro-quadrupole orders compete. Each phase is characterized by symmetry
breaking in the sector of (sublattice Z_2)x(reflection Z_2 for the order
parameter). When Z_3 anisotropy and magnetic field vary, it turns out that this
system is a good playground for various multicritical points; bicritical and
tetracritical points emerge in a finite field. Another important finding is
about the scaling of parasitic ferro quadrupole order at the zero-field
critical point. This is the secondary order parameter induced by the primary
antiferro order, and its critical exponent beta'=0.815 clearly differs from the
expected value that is twice the value for the primary order parameter. The
corresponding correlation length exponent is also different, nu'=0.597(12). We
also discuss relation of the present effective quadrupole models with the
3-state Potts model as well as implication to undertanding of orbital orders in
Pr-based 1-2-20 compounds.


title: Poincar\'e inequalities for the maximal function

abstract:
  We study generalized Poincar\'e inequalities. We prove that if a function
satisfies a suitable inequality of Poincar\'e type, then the Hardy-Littlewood
maximal function also obeys a meaningful estimate of similar form. As a
by-product, we get a unified approach to proving that the maximal operator is
bounded on Sobolev, Lipschitz and BMO spaces.


title:
Doping dependence and electron-boson coupling in the ultrafast
  relaxation of hot electron populations in Ba(Fe_{1-x}Co_x)_2As_2

abstract:
  Using femtosecond time- and angle-resolved photoemission spectroscopy we
investigate the effect of electron doping on the electron dynamics in
Ba(Fe_{1-x}Co_x)_2As_2 in a range of 0 < x < 0.15 at temperatures slightly
above the N\'eel temperature. By analyzing the time-dependent photoemission
intensity of the pump laser excited population as a function of energy, we
found that the relaxation times at 0 < E-E_F < 0.2 eV are doping dependent and
about 100 fs shorter at optimal doping than for overdoped and parent compounds.
Analysis of the relaxation rates also reveals the presence of a pump fluence
dependent step in the relaxation time at E-E_F = 200meV which we explain by
coupling of the excited electronic system to a boson of this energy. We compare
our results with static ARPES and transport measurements and find disagreement
and agreement concerning the doping-dependence, respectively. We discuss the
effect of the electron-boson coupling on the energy-dependent relaxation and
assign the origin of the boson to a magnetic excitation.


title:
CHISL: The Combined High-resolution and Imaging Spectrograph for the
  LUVOIR Surveyor

abstract:
  NASA is currently carrying out science and technical studies to identify its
next astronomy flagship mission, slated to begin development in the 2020s. It
has become clear that a Large Ultraviolet/Optical/IR (LUVOIR) Surveyor mission
(primary diameter 12 m, 1000 Ang - 2 micron spectroscopic bandpass) can carry
out the largest number of NASA's exoplanet and astrophysics science goals over
the coming decades. There are technical challenges for several aspects of the
LUVOIR Surveyor concept, including component level technology readiness
maturation and science instrument concepts for a broadly capable ultraviolet
spectrograph. We present the scientific motivation for, and a preliminary
design of, a multiplexed ultraviolet spectrograph to support both the exoplanet
and astrophysics goals of the LUVOIR Surveyor mission concept, the Combined
High-resolution and Imaging Spectrograph for the LUVOIR Surveyor (CHISL). CHISL
includes a high-resolution (R 120,000; 1000 - 1700 Ang) point-source
spectroscopy channel and a medium resolution (R > 14,000 from 1000 - 2000 Ang
in a single observation and R 24,000 - 35,000 in multiple grating settings)
imaging spectroscopy channel. We present the CHISL concept, a small sample of
representative science cases, and the primary technological hurdles. We are
actively engaged in laboratory and flight characterization efforts for
CHISL-enabling technologies as components on sounding rocket payloads under
development at the University of Colorado. We describe two payloads that are
designed to be pathfinder instruments for the high-resolution (CHESS) and
imaging spectroscopy (SISTINE) arms of CHISL. We are carrying out this
instrument design, characterization, and flight-testing today to support the
new start of a LUVOIR Surveyor mission in the next decade.


title: The "Horizon-T" Experiment: Extensive Air Showers Detection

abstract:
  Horizon-T is an innovative detector system constructed to study Extensive Air
Showers (EAS) in the energy range above 10^16 eV coming from a wide range of
zenith angles (0 - 85 degrees). The system is located at Tien Shan
high-altitude Science Station of Lebedev Physical Institute of the Russian
Academy of Sciences at approximately 3340 meters above the sea level. It
consists of eight charged particle detection points separated by the distance
up to one kilometer as well as optical detector subsystem to view the
Vavilov-Cerenkov light from the EAS. The time resolution of charged particles
and Vavilov-Cerenkov light photons passage of the detector system is a few ns.
This level of resolution allows conducting research of atmospheric development
of individual EAS.


title: Structured Prediction of 3D Human Pose with Deep Neural Networks

abstract:
  Most recent approaches to monocular 3D pose estimation rely on Deep Learning.
They either train a Convolutional Neural Network to directly regress from image
to 3D pose, which ignores the dependencies between human joints, or model these
dependencies via a max-margin structured learning framework, which involves a
high computational cost at inference time.
  In this paper, we introduce a Deep Learning regression architecture for
structured prediction of 3D human pose from monocular images that relies on an
overcomplete auto-encoder to learn a high-dimensional latent pose
representation and account for joint dependencies. We demonstrate that our
approach outperforms state-of-the-art ones both in terms of structure
preservation and prediction accuracy.


title:
A new characterization of ultraspherical, Hermite, and Chebyshev
  polynomials of the first kind

abstract:
  We show that the only polynomial sets with a generating function of the form
F (xt -- R(t)) and satisfying a three-term recursion relation are the monomial
set and the rescaled ultraspherical, Hermite, and Chebyshev polynomials of the
first kind.


title: Dynamic vibronic coupling in InGaAs quantum dots

abstract:
  The electron-phonon coupling in self-assembled InGaAs quantum dots is
relatively weak at low light intensities, which means that the zero-phonon line
in emission is strong compared to the phonon sideband. However, the coupling to
acoustic phonons can be dynamically enhanced in the presence of an intense
optical pulse tuned within the phonon sideband. Recent experiments have shown
that this dynamic vibronic coupling can enable population inversion to be
achieved when pumping with a blue-shifted laser and for rapid de-excitation of
an inverted state with red detuning. In this paper we confirm the incoherent
nature of the phonon-assisted pumping process and explore the temperature
dependence of the mechanism. We also show that a combination of blue- and
red-shifted pulses can create and destroy an exciton within a timescale ~20 ps
determined by the pulse duration and ultimately limited by the phonon
thermalisation time.


title: The Red and Featureless Outer Disks of Nearby Spiral Galaxies

abstract:
  We present results from deep, wide-field surface photometry of three nearby
(D=4--7 Mpc) spiral galaxies: M94 (NGC 4736), M64 (NGC 4826), and M106 (NGC
4258). Our imaging reaches limiting surface brightnesses of $\mu_{B} \sim$ 28
-- 30 mag arcsec$^{-2}$ and probes colors down to $\mu_{B} \sim$ 27.5 mag
arcsec$^{-2}$. We compare our broadband optical data to available ultraviolet
and high column-density HI data to better constrain the star forming history
and stellar populations of the outermost parts of each galaxy's disk. Each
galaxy has a well-defined radius beyond which little star formation occurs and
the disk light appears both azimuthally smooth and red in color, suggestive of
old, well-mixed stellar populations. Given the lack of ongoing star formation
or blue stellar populations in these galaxies' outer disks, the most likely
mechanisms for their formation are dynamical processes such as disk heating or
radial migration, rather than inside-out growth of the disks. This is also
implied by the similarity in outer disk properties despite each galaxy showing
distinct levels of environmental influence, from a purely isolated galaxy (M94)
to one experiencing weak tidal perturbations from its satellite galaxies (M106)
to a galaxy recovering from a recent merger (M64), suggesting that a variety of
evolutionary histories can yield similar outer disk structure. While this
suggests a common secular mechanism for outer disk formation, the large extent
of these smooth, red stellar populations---which reach several disk
scalelengths beyond the galaxies' spiral structure---may challenge models of
radial migration given the lack of any non-axisymmetric forcing at such large
radii.


title:
Strong coupling superconductivity revealed by scanning tunneling
  microscope in tetragonal FeS

abstract:
  We investigate the electronic properties of the tetragonal FeS superconductor
by using scanning tunneling microscope/spectroscopy. It is found that the
typical tunneling spectrum on the top layer of sulfur can be nicely fitted with
an anisotropic s-wave or a combination of two superconducting components in
which one may have a highly anisotropic or nodal like superconducting gap. The
fittings lead to the maximum superconducting gap $\Delta_{max}\approx$
0.90$\;$meV, which yields a ratio of 2$\Delta_{max}/k_BT_c\approx$ 4.65. This
value is larger than that of the predicted value 3.53 by the BCS theory in the
weak coupling limit, indicating a strong coupling superconductivity. Two kinds
of defects are observed on the surface, which can be assigned to the defects on
the S sites (four-fold image) and Fe sites (dumbbell shape). Impurity induced
resonance states are found only for the former defects and stay at zero-bias
energy.


title:
How to calculate dark matter direct detection exclusion limits that are
  consistent with gamma rays from annihilation in the Milky Way halo

abstract:
  When comparing constraints on the Weakly Interacting Massive Particle (WIMP)
properties from direct and indirect detection experiments it is crucial that
the assumptions made about the dark matter (DM) distribution are realistic and
consistent. For instance, if the Fermi-LAT Galactic centre GeV gamma-ray excess
was due to WIMP annihilation, its morphology would be incompatible with the
Standard Halo Model that is usually used to interpret data from direct
detection experiments. In this article, we calculate exclusion limits from
direct detection experiments using self-consistent velocity distributions,
derived from mass models of the Milky Way where the DM halo has a generalized
NFW profile. We use two different methods to make the mass model compatible
with a DM interpretation of the Galactic centre gamma-ray excess. Firstly, we
fix the inner slope of the DM density profile to the value that best fits the
morphology of the excess. Secondly, we allow the inner slope to vary and
include the morphology of the excess in the data sets used to constrain the
gravitational potential of the Milky Way. The resulting direct detection limits
differ significantly from those derived using the Standard Halo Model, in
particular for light WIMPs, due to the differences in both the local DM density
and velocity distribution.


title: Co-existence of Weyl Fermion and Massless Triply Degenerate Nodal Points

abstract:
  By using first-principles calculations, we propose that WC-type ZrTe is a new
type of topological semimetal (TSM). It has six pairs of chiral Weyl nodes in
its first Brillouin zone, but it is distinguished from other existing TSMs by
having additional two paris of massless fermions with triply degenerate nodal
points as proposed in the isostructural compounds TaN and NbN. The mirror
symmetry, three-fold rotational symmetry and time-reversal symmetry require all
of the Weyl nodes to have the same velocity vectors and locate at the same
energy level. The Fermi arcs on different surfaces are shown, which may be
measured by future experiments. It demonstrates that the "material universe"
can support more intriguing particles simultaneously.


title:
Propagation and filtering of elastic and electromagnetic waves in
  piezoelectric composite structures

abstract:
  In this article we discuss the modelling of elastic and electromagnetic wave
propagation through one- and two-dimensional structured piezoelectric solids.
Dispersion and the effect of piezoelectricity on the group velocity and
positions of stop bands are studied in detail. We will also analyze the
reflection and transmission associated with the problem of scattering of an
elastic wave by a heterogeneous piezoelectric stack. Special attention is given
to the occurrence of transmission resonances in finite stacks and their
dependence on a piezoelectric effect. A 2D doubly-periodic piezoelectric
checkerboard structure is subsequently introduced, for which the dispersion
surfaces for Bloch waves have been constructed and analysed, with the emphasis
on the dynamic anisotropy and special features of standing waves within the
piezoelectric structure.


title:
Topologically close-packed phases in binary transition-metal compounds:
  matching high-throughput ab initio calculations to an empirical structure map

abstract:
  In steels and single-crystal superalloys the control of the formation of
topologically close-packed (TCP) phases is critical for the performance of the
material. The structural stability of TCP phases in multi-component
transition-metal alloys may be rationalised in terms of the average
valence-electron count $\bar{N}$ and the composition-dependent relative
volume-difference $\overline{\Delta V/V}$. We elucidate the interplay of these
factors by comparing density-functional theory calculations to an empirical
structure map based on experimental data. In particular, we calculate the heat
of formation for the TCP phases A15, C14, C15, C36, $\chi$, $\mu$, and $\sigma$
for all possible binary occupations of the Wyckoff positions. We discuss the
isovalent systems V/Nb-Ta to highlight the role of atomic-size difference and
observe the expected stabilisation of C14/C15/C36/$\mu$ by $\overline{\Delta
V/V}$ at $\Delta N=0$ in V-Ta. In the systems V/Nb-Re, we focus on the
well-known trend of A15$- \sigma - \chi$ stability with increasing $\bar{N}$
and show that the influence of $\overline{\Delta V/V}$ is too weak to stabilise
C14/C15/C36/$\mu$ in Nb-Re. As an example for a significant influence of both
$\bar{N}$ and $\overline{\Delta V/V}$, we also consider the systems Cr/Mo-Co.
Here the sequence A15$- \sigma - \chi$ is observed in both systems but in Mo-Co
the large size-mismatch stabilises C14/C15/C36/$\mu$. We also include V/Nb-Co
that cover the entire valence range of TCP stability and also show the
stabilisation of C14/C15/C36/$\mu$. Moreover, the combination of a large volume
difference with a large mismatch in valence-electron count reduces the
stability of the A15/$\sigma$/$\chi$ phases in Nb-Co as compared to V-Co. By
comparison to non-magnetic calculations we also find that magnetism is of minor
importance for the structural stability of TCP phases in Cr/Mo-Co and in
V/Nb-Co.


title: C*-algebras of Boolean inverse monoids - traces and invariant means

abstract:
  To a Boolean inverse monoid $S$ we associate a universal C*-algebra
$C_B^*(S)$ and show that it is equal to Exel's tight C*-algebra of $S$. We then
show that any invariant mean on $S$ (in the sense of Kudryavtseva, Lawson, Lenz
and Resende) gives rise to a trace on $C_B^*(S)$, and vice-versa, under a
condition on $S$ equivalent to the underlying groupoid being Hausdorff. Under
certain mild conditions, the space of traces of $C_B^*(S)$ is shown to be
isomorphic to the space of invariant means of $S$. We then use many known
results about traces of C*-algebras to draw conclusions about invariant means
on Boolean inverse monoids; in particular we quote a result of Blackadar to
show that any metrizable Choquet simplex arises as the space of invariant means
for some AF inverse monoid $S$.


title: A note on lattice ordered $C^*$-algebras and Perron--Frobenius theory

abstract:
  A classical result of Sherman says that if the space of self-adjoint elements
in a $C^*$-algebra $\mathcal{A}$ is a lattice with respect to its canonical
order, then $\mathcal{A}$ is commutative. We give a new proof of this theorem
which shows that it is intrinsically connected with the spectral theory of
positive operator semigroups. Our methods also show that some important
Perron--Frobenius like spectral results fail to hold in any non-commutative
$C^*$-algebra.


title: Graph limits of random graphs from a subset of connected $k$-trees

abstract:
  For any set $\Omega$ of non-negative integers such that $\{0,1\}\subseteq
\Omega$ and $\{0,1\}\ne \Omega$, we consider a random $\Omega$-$k$-tree ${\sf
G}_{n,k}$ that is uniformly selected from all connected $k$-trees of $(n+k)$
vertices where the number of $(k+1)$-cliques that contain any fixed $k$-clique
belongs to $\Omega$. We prove that ${\sf G}_{n,k}$, scaled by
$(kH_{k}\sigma_{\Omega})/(2\sqrt{n})$ where $H_{k}$ is the $k$-th Harmonic
number and $\sigma_{\Omega}>0$, converges to the Continuum Random Tree
$\mathcal{T}_{{\sf e}}$. Furthermore, we prove the local convergence of the
rooted random $\Omega$-$k$-tree ${\sf G}_{n,k}^{\circ}$ to an infinite but
locally finite random $\Omega$-$k$-tree ${\sf G}_{\infty,k}$.


title: Large deviations of continuous regular conditional probabilities

abstract:
  We study product regular conditional probabilities under measures of two
coordinates with respect to the second coordinate that are weakly continuous on
the support of the marginal of the second coordinate. Assuming that there
exists a sequence of probability measures on the product space that satisfies a
large deviation principle, we present necessary and sufficient conditions for
the conditional probabilities under these measures to satisfy a large deviation
principle. The arguments of these conditional probabilities are assumed to
converge. A way to view regular conditional probabilities as a special case of
product regular conditional probabilities is presented. This is used to derive
conditions for large deviations of regular conditional probabilities. In
addition, we derive a Sanov-type theorem for large deviations of the empirical
distribution of the first coordinate conditioned on fixing the empirical
distribution of the second coordinate.


title: Probing Higgs-Portal Dark Matter with Weakly Interacting Mediators

abstract:
  The hypothesis of dark matter interacting with the standard model uniquely
via the Higgs portal is severely challenged by experiments. However, if dark
matter is a fermion, the Higgs-portal interaction implies the presence of
mediators, which can change the phenomenology significantly. This article
discusses the impact of weakly-interacting mediators on the dark-matter relic
abundance, direct detection, and collider searches. At the LHC, a typical
signature of Higgs-portal fermion dark matter features soft leptons and missing
energy, similarly to gaugino production in models with supersymmetry. We
suggest to re-interpret existing gaugino searches in the context of
Higgs-portal models and to extend future searches to the broader class of dark
sectors with weakly-interacting fermions.


title: Integer Set Reduction for Stochastic Mixed-Integer Programming

abstract:
  Two-stage stochastic mixed-integer programming (SMIP) problems with general
integer variables in the second-stage are generally difficult to solve. This
paper develops the theory of integer set reduction for characterizing the
subset of the convex hull of feasible integer points of the second-stage
subproblem which can be used for solving the SMIP. The basic idea is to
consider a small enough subset of feasible integer points that is necessary for
generating a valid inequality for the integer subproblem. An algorithm for
obtaining such a subset based on the solution of the subproblem LP-relaxation
is then devised and incorporated into the Fenchel decomposition method for
SMIP. To demonstrate the performance of the new integer set reduction
methodology, a computational study based on randomly generated test instances
was performed. The results of the study show that integer set reduction
provides significant gains in terms of generating cuts faster leading to better
bounds in solving SMIPs than using a direct solver.


title: Enhanced Twitter Sentiment Classification Using Contextual Information

abstract:
  The rise in popularity and ubiquity of Twitter has made sentiment analysis of
tweets an important and well-covered area of research. However, the 140
character limit imposed on tweets makes it hard to use standard linguistic
methods for sentiment classification. On the other hand, what tweets lack in
structure they make up with sheer volume and rich metadata. This metadata
includes geolocation, temporal and author information. We hypothesize that
sentiment is dependent on all these contextual factors. Different locations,
times and authors have different emotional valences. In this paper, we explored
this hypothesis by utilizing distant supervision to collect millions of
labelled tweets from different locations, times and authors. We used this data
to analyse the variation of tweet sentiments across different authors, times
and locations. Once we explored and understood the relationship between these
variables and sentiment, we used a Bayesian approach to combine these variables
with more standard linguistic features such as n-grams to create a Twitter
sentiment classifier. This combined classifier outperforms the purely
linguistic classifier, showing that integrating the rich contextual information
available on Twitter into sentiment classification is a promising direction of
research.


title: Derivatives at the Boundary for Analytic Lipschitz Functions

abstract:
  We consider the behaviour of holomorphic functions on a bounded open subset
of the plane, satisfying a Lipschitz condition with exponent $\alpha$, with
$0<\alpha<1$, in the vicinity of an exceptional boundary point where all such
functions exhibit some kind of smoothness. Specifically, we consider the
relation between the abstract idea of a bounded point derivation on the algebra
of such functions and the classical complex derivative evaluated as a limit of
difference quotients. We show that whenever such a bounded point derivation
exists at a boundary point $b$, it may be evaluated by taking a limit of
classical difference quotients, for approach from a set having full area
density at $b$.


title: Human Action Localization with Sparse Spatial Supervision

abstract:
  We introduce an approach for spatio-temporal human action localization using
sparse spatial supervision. Our method leverages the large amount of annotated
humans available today and extracts human tubes by combining a state-of-the-art
human detector with a tracking-by-detection approach. Given these high-quality
human tubes and temporal supervision, we select positive and negative tubes
with very sparse spatial supervision, i.e., only one spatially annotated frame
per instance. The selected tubes allow us to effectively learn a
spatio-temporal action detector based on dense trajectories or CNNs. We conduct
experiments on existing action localization benchmarks: UCF-Sports, J-HMDB and
UCF-101. Our results show that our approach, despite using sparse spatial
supervision, performs on par with methods using full supervision, i.e., one
bounding box annotation per frame. To further validate our method, we introduce
DALY (Daily Action Localization in YouTube), a dataset for realistic action
localization in space and time. It contains high quality temporal and spatial
annotations for 3.6k instances of 10 actions in 31 hours of videos (3.3M
frames). It is an order of magnitude larger than existing datasets, with more
diversity in appearance and long untrimmed videos.


title: A sharp Bogomolov-type bound

abstract:
  We prove a sharp lower bound for the essential minimum of a non-translate
variety in certain abelian varieties. This uses and generalises a result of
Galateau. Our bound is a new step in direction of an abelian analogue by David
and Philippon of a toric conjecture of Amoroso and David and has applications
in the framework of anomalous intersections.


title: One-dimensional Ising model with multispin interactions

abstract:
  We study the spin-$1/2$ Ising chain with multispin interactions $K$ involving
the product of $m$ successive spins, for general values of $m$. Using a change
of spin variables the zero-field partition function of a finite chain is
obtained for free and periodic boundary conditions (BC) and we calculate the
two-spin correlation function. When placed in an external field $H$ the system
is shown to be self-dual. Using another change of spin variables the
one-dimensional (1D) Ising model with multispin interactions in a field is
mapped onto a zero-field rectangular Ising model with first-neighbour
interactions $K$ and $H$. The 2D system, with size $m\times N/m$, has the
topology of a cylinder with helical BC. In the thermodynamic limit
$N/m\to\infty$, $m\to\infty$, a 2D critical singularity develops on the
self-duality line, $\sinh 2K\sinh 2H=1$.


title:
Termination of the MRI via parasitic instabilities in core-collapse
  supernovae: influence of numerical methods

abstract:
  We study the influence of numerical methods and grid resolution on the
termination of the magnetorotational instability (MRI) by means of parasitic
instabilities in three-dimensional shearing-disc simulations reproducing
typical conditions found in core-collapse supernovae. Whether or not the MRI is
able to amplify weak magnetic fields in this context strongly depends, among
other factors, on the amplitude at which its growth terminates. The qualitative
results of our study do not depend on the numerical scheme. In all our models,
MRI termination is caused by Kelvin-Helmholtz instabilities, consistent with
theoretical predictions. Quantitatively, however, there are differences, but
numerical convergence can be achieved even at relatively low grid resolutions
if high-order reconstruction methods are used.


title: A Note On A Norm-Preserving Continuous Galerkin Time Stepping Scheme

abstract:
  In this note we shall devise a variable-order continuous Galerkin time
stepping method which is especially geared towards norm-preserving dynamical
systems. In addition, we will provide an a posteriori estimate for the
$L^\infty$-error.


title:
Two Photon Exchange in Impact Parameter Space in the Relativistic
  Eikonal Approximation for Elastic e - N Scattering

abstract:
  Using the relativistic Eikonal approximation, we study the one and two photon
exchange amplitudes in elastic electron-nucleon scattering for the case of
transversely polarized nucleons with unpolarized electrons beam. In our
approach, we utilize the convolution theory of Fourier transforms and the
transverse charge density in transverse momentum space to evaluate the one and
two photon exchange Eikonal amplitudes. The results obtained for the $2\gamma$
amplitude in impact parameter space are compared to the corresponding 4D case.
We show that while the one and two photon cross sections are azimuthally
symmetric, the interference term between them is azimuthally asymmetric, which
is an indication of an azimuthal single spin asymmetry for proton and neutron
which can be attributed to the fact that the nucleon charge density is
transversely (azimuthally) distorted in the transverse plane for transversely
polarized nucleons. In addition, the calculations of the interference term for
proton and neutron show agreement in sign and magnitude of the existence data
and calculations for transverse target single spin asymmetry.


title:
Observation of Majorana Quasiparticles Surface States in Superfluid
  ${^3}$He-B by Heat Capacity Measurements

abstract:
  We report about direct measurements of heat capacity of Majorana
quasiparticles in superfluid ${^3}$He-B which appear near the surface of the
experimental bolometer on the coherence length ${\xi}$. Two bolometers with
different surface-to-volume ratios were used which allows us to have different
calibrated contributions from Majorana quasiparticles to the ${^3}$He heat
capacity. Estimations of possible impact of ${^3}$He layers adsorbed on the
walls of the bolometer have been done.


title: A sieve problem and its application

abstract:
  Let $\theta$ be an arithmetic function and let $\mathcal{B}$ be the set of
positive integers $n=p_1^{\alpha_1} \cdots p_k^{\alpha_k}$, which satisfy
$p_{j+1} \le \theta ( p_1^{\alpha_1}\cdots p_{j}^{\alpha_{j}})$ for $0\le j <
k$. We show that $\mathcal{B}$ has a natural density, provide a criterion to
determine whether this density is positive, and give various estimates for the
counting function of $\mathcal{B}$. When $\theta(n)/n$ is non-decreasing, the
set $\mathcal{B}$ coincides with the set of integers $n$ whose divisors $1=d_1<
d_2 < \ldots <d_{\tau(n)}=n$ satisfy $d_{j+1} \le \theta( d_j )$ for $1\le j
<\tau(n)$.


title:
Near-Earth asteroid (3200) Phaethon. Characterization of its orbit, spin
  state, and thermophysical parameters

abstract:
  The near-Earth asteroid (3200) Phaethon is an intriguing object: its
perihelion is at only 0.14 au and is associated with the Geminid meteor stream.
We aim to use all available disk-integrated optical data to derive a reliable
convex shape model of Phaethon. By interpreting the available space- and
ground-based thermal infrared data and Spitzer spectra using a thermophysical
model, we also aim to further constrain its size, thermal inertia, and visible
geometric albedo. We applied the convex inversion method to the new optical
data obtained by six instruments and to previous observations. The convex shape
model was then used as input for the thermophysical modeling. We also studied
the long-term stability of Phaethon's orbit and spin axis with a numerical
orbital and rotation-state integrator. We present a new convex shape model and
rotational state of Phaethon: a sidereal rotation period of 3.603958(2) h and
ecliptic coordinates of the preferred pole orientation of (319$^{\circ}$,
$-$39$^{\circ}$) with a 5$^{\circ}$ uncertainty. Moreover, we derive its size
($D$=5.1$\pm$0.2 km), thermal inertia ($\Gamma$=600$\pm$200 J m$^{-2}$
s$^{-1/2}$ K$^{-1}$), geometric visible albedo
($p_{\mathrm{V}}$=0.122$\pm$0.008), and estimate the macroscopic surface
roughness. We also find that the Sun illumination at the perihelion passage
during the past several thousand years is not connected to a specific area on
the surface, which implies non-preferential heating.


title: Mesoscopic central limit theorem for general $\beta$-ensembles

abstract:
  We prove that the linear statistics of eigenvalues of $\beta$-log gasses
satisfying the one-cut and off-critical assumption with a potential $V \in
C^6(\mathbb{R})$ satisfy a central limit theorem at all mesoscopic scales
$\alpha \in (0; 1)$. We prove this for compactly supported test functions $f
\in C^5(\mathbb{R})$ using loop equations at all orders along with rigidity
estimates.


title:
Quantum computing with atomic qubits and Rydberg interactions: Progress
  and challenges

abstract:
  We present a review of quantum computation with neutral atom qubits. After an
overview of architectural options and approaches to preparing large qubit
arrays we examine Rydberg mediated gate protocols and fidelity for two- and
multi-qubit interactions. Quantum simulation and Rydberg dressing are
alternatives to circuit based quantum computing for exploring many body quantum
dynamics. We review the properties of the dressing interaction and provide a
quantitative figure of merit for the complexity of the coherent dynamics that
can be accessed with dressing. We conclude with a summary of the current status
and an outlook for future progress.


title:
Deriving the properties of coronal pressure fronts in 3-D: application
  to the 17 May 2012 ground level enhancement

abstract:
  We study the link between an expanding coronal shock and the energetic
particles measured near Earth during the Ground Level Enhancement (GLE) of 17
May 2012. We developed a new technique based on multipoint imaging to
triangulate the 3-D expansion of the shock forming in the corona. It uses
images from three vantage points by mapping the outermost extent of the coronal
region perturbed by the pressure front. We derive for the first time the 3-D
velocity vector and the distribution of Mach numbers, $M_{FM}$, of the entire
front as a function of time. Our approach uses magnetic field reconstructions
of the coronal field, full magneto-hydrodynamic simulations and imaging
inversion techniques. We find that the highest $M_{FM}$ values appear near the
coronal neutral line within a few minutes of the Coronal Mass Ejection (CME)
onset; this neutral line is usually associated with the source of the
heliospheric current and plasma sheet. We illustrate the variability of the
shock speed, shock geometry and Mach number along different modeled magnetic
field lines. Despite the level of uncertainty in deriving the shock Mach
numbers, all employed reconstruction techniques show that the release time of
GeV particles occurs when the coronal shock becomes super-critical
($M_{FM}>3$). Combining in-situ measurements with heliospheric imagery, we also
demonstrate that magnetic connectivity between the accelerator (the coronal
shock of 17 May 2012) and the near-Earth environment is established via a
magnetic cloud that erupted from the same active region roughly five days
earlier.


title: A general realistic treatment of the disk paradox

abstract:
  Mechanical angular momentum is not conserved in systems involving
electromagnetic fields with non-zero electromagnetic field angular momentum.
Conservation is restored only if the total (mechanical and field) angular
momentum is considered. Previous studies have investigated this effect, known
as "Feynman's Electromagnetic Paradox" or simply "Disk Paradox" in the context
of idealized systems (infinite or infinitesimal solenoids and charged cylinders
etc). In the present analysis we generalize previous studies by considering
more realistic systems with finite components and demonstrating explicitly the
conservation of the total angular momentum. This is achieved by expressing both
the mechanical and the field angular momentum in terms of charges and magnetic
field fluxes through various system components. Using this general expression
and the closure of magnetic field lines, we demonstrate explicitly the
conservation of total angular momentum in both idealized and realistic systems
(finite solenoid concentric with two charged cylinders, much longer than the
solenoid) taking all the relevant terms into account including the flux outside
of the solenoid. This formalism has the potential to facilitate a simpler and
more accurate demonstration of total angular momentum conservation in
undergraduate physics electromagnetism laboratories.


title:
Magic wavelengths, matrix elements, polarizabilities, and lifetimes of
  Cs

abstract:
  Motivated by recent interest in their applications, we report a systematic
study of Cs atomic properties calculated by a high-precision relativistic
all-order method. Excitation energies, reduced matrix elements, transition
rates, and lifetimes are determined for levels with principal quantum numbers
$n \leq 12$ and orbital angular momentum quantum numbers $l \leq 3$.
Recommended values and estimates of uncertainties are provided for a number of
electric-dipole transitions and the electric dipole polarizabilities of the
$ns$, $np$, and $nd$ states. We also report a calculation of the electric
quadrupole polarizability of the ground state. We display the dynamic
polarizabilities of the $6s$ and $7p$ states for optical wavelengths between
1160 nm and 1800 nm and identify corresponding magic wavelengths for the
$6s-7p_{1/2}$, $6s-7p_{3/2}$ transitions. The values of relevant matrix
elements needed for polarizability calculations at other wavelengths are
provided.

categories: physics.atom-ph cond-mat.quant-gas physics.optics quant-ph


title:
Direct observation of dynamic modes excited in a magnetic insulator by
  pure spin current

abstract:
  Excitation of magnetization dynamics by pure spin currents has been recently
recognized as an enabling mechanism for spintronics and magnonics, which allows
implementation of spin-torque devices based on low-damping insulating magnetic
materials. Here we report the first spatially-resolved study of the dynamic
modes excited by pure spin current in nanometer-thick microscopic insulating
Yttrium Iron Garnet disks. We show that these modes exhibit nonlinear
self-broadening preventing the formation of the self-localized magnetic bullet,
which plays a crucial role in the stabilization of the single-mode
magnetization oscillations in all-metallic systems. This peculiarity associated
with the efficient nonlinear mode coupling in low-damping materials can be
among the main factors governing the interaction of pure spin currents with the
dynamic magnetization in high-quality magnetic insulators.


title: Multimodal Sparse Coding for Event Detection

abstract:
  Unsupervised feature learning methods have proven effective for
classification tasks based on a single modality. We present multimodal sparse
coding for learning feature representations shared across multiple modalities.
The shared representations are applied to multimedia event detection (MED) and
evaluated in comparison to unimodal counterparts, as well as other feature
learning methods such as GMM supervectors and sparse RBM. We report the
cross-validated classification accuracy and mean average precision of the MED
system trained on features learned from our unimodal and multimodal settings
for a subset of the TRECVID MED 2014 dataset.


title:
Berry phase, entanglement entropy, and algebraic properties of ground
  states of BCS and BEC superfluids

abstract:
  By using Bogoliubov transformations to construct the ground states of
fermionic Bardeen-Cooper-Schrieffer (BCS) superfluids and weakly-interacting
Bose gases supporting Bose Einstein Condensation (BEC), their algebraic
structures and implications can be analyzed in detail. Both ground states are
generalized squeezed coherent states saturating a generalized Heisenberg
uncertainty relation, and they acquire quantized Berry phases when the
corresponding systems are transported along a closed path in their parameter
spaces. While the Berry phase of the BCS ground state depends on the total
particle number, the Berry phase of the BEC ground state depends only on the
particles outside the BEC. The Berry phases are associated with magnetic
monopoles in the parameter spaces and we found that the Dirac quantization
condition is satisfied. Moreover, both ground states are entangled states of
the fermion or boson quanta and we found the entanglement entropy quantifying
the internal correlations. A fixed particle-number approach of fermionic
superfluids does not saturate the generalized uncertainty relation, exhibits
internal entanglement, and gives corresponding Berry phase. In addition, the
algebraic structures of the ground states can be classified by the $q$-deformed
Hopf algebra, $\bigoplus_{\mathbf{k}}h_{q_{\mathbf{k}}}(1)$ for bosons and
$q$-deformed Hopf superalgebra $\bigoplus_{\mathbf{k}}h_{q_{\mathbf{k}}}(1|1)$
for fermions, respectively.

categories: cond-mat.quant-gas cond-mat.supr-con math-ph math.MP


title: Spin-lattice coupling mediated multiferroicity in (ND4)2FeCl5D2O

abstract:
  We report a neutron diffraction study of the multiferroic mechanism in
(ND4)2FeCl5D2O, a molecular compound that exhibits magnetically induced
ferroelectricity. This material exhibits two successive magnetic transitions on
cooling: a long-range order transition to an incommensurate (IC) collinear
sinusoidal spin state at TN=7.3 K, followed by a second transition to an IC
cycloidal spin state at TFE=6.8 K, the later of which is accompanied by
spontaneous ferroelectric polarization. The cycloid structure is strongly
distorted by spin-lattice coupling as evidenced by the observations of both odd
and even higher-order harmonics associated with the cycloid wave vector, and a
weak commensurate phase that coexists with the IC phase. The appearance of the
2nd-order harmonic coincides with the onset of the electric polarization,
thereby providing unambiguous evidence that the induced electric polarization
is mediated by the spin-lattice interaction. Our results for this system, in
which the orbital angular momentum is expected to be quenched, are remarkably
similar to those of the prototypical TbMnO3, in which the magnetoelectric
effect is attributed to spin-orbit coupling.


title:
The Iso-electronic Series $Ca_{2-x}Sr_{x}RuO_{4}$: Structural
  Distortion, Effective Dimensionality, Spin Fluctuations and Quantum
  Criticality

abstract:
  The iso-electronic $d^{4}$ compounds of the $4d$ series show rich phase
diagrams due to competing spin, charge and orbital degrees of freedom in
presence of strong correlations and structural distortions. One such
iso-electronic series, $Ca_{2-x}Sr_{x}RuO_{4}$, is studied within the GGA (and
spin-orbit coupled GGA) plus DMFT formalism using the hybridization expansion
of continuous time Quantum Monte Carlo solver. While the local dynamical
correlations make $Sr_{2}RuO_{4}$ a Hund's metal, they drive $Ca_{2}RuO_{4}$ to
a Mott insulating ground state. We study the dynamic and static single-particle
and local irreducible vertex-corrected two-particle responses at three
different points ($x = 2.0, 0.5, 0.0$) to understand the anomalous cross-over
from Hund's metal ($x = 2.0 $) to a Mott insulator ($x = 0 $) and find that a
structural distortion is likely to be responsible for the cross-over. Further,
dynamical correlations reveal that the band-width ($W$) of the Hund's metal is
larger than its effective local Hubbard $U$, and a finite Hund's coupling
$J_{H}$ helps it remain in a bad metallic and nearly spin-frozen state over a
large temperature range. $Ca_{2}RuO_{4}$, on the other hand, is intrinsically
driven to the proximity of a Mott transition due to narrowing of band width
($U/W > 1.5$), though its finite temperature excitations indicate bad
metallicity. We show that there is a critical end point of second-order
structural transition at $x = 0.5$, where spin fluctuations become critically
singular and follow the exact scaling of conformally invariant boundary field
theory. The critical end point of quasi-$3D$ nature is associated with an
effective dimensional cross-over between the $x = 2.0$ and $x=0.0$ quasi-$2D$
structures. Finally we draw a modified magnetic phase diagram of the material,
showing a fan-like region starting from the quantum critical end point at $x =
0.5.$


title: Combinatorially Generated Piecewise Activation Functions

abstract:
  In the neuroevolution literature, research has primarily focused on evolving
the number of nodes, connections, and weights in artificial neural networks.
Few attempts have been made to evolve activation functions. Research in
evolving activation functions has mainly focused on evolving function
parameters, and developing heterogeneous networks by selecting from a fixed
pool of activation functions. This paper introduces a novel technique for
evolving heterogeneous artificial neural networks through combinatorially
generating piecewise activation functions to enhance expressive power. I
demonstrate this technique on NeuroEvolution of Augmenting Topologies using
ArcTan and Sigmoid, and show that it outperforms the original algorithm on
non-Markovian double pole balancing. This technique expands the landscape of
unconventional activation functions by demonstrating that they are competitive
with canonical choices, and introduces a purview for further exploration of
automatic model selection for artificial neural networks.


title:
A frame-dependent gravitational effective action mimics a cosmological
  constant, but modifies the black hole horizon

abstract:
  A frame dependent effective action motivated by the postulates of three-space
general coordinate invariance and Weyl scaling invariance exactly mimics a
cosmological constant in Robertson-Walker spacetimes. However, in a static
spherically symmetric Schwarzschild-like geometry it modifies the black hole
horizon structure within microscopic distances of the nominal horizon, in such
a way that $g_{00}$ never vanishes. This could have important implications for
the black hole "information paradox".


title:
An undergraduate laboratory experiment on measuring the velocity of
  light with a catastrophic machine

abstract:
  An experimental setup for electrostatic measurement of $\varepsilon_0$,
separated magneto-static measurement of $\mu_0$ and determination of the
velocity of light $c=1/\sqrt{\varepsilon_0 \mu_0}$ according to Maxwell theory
with percent accuracy is described. No forces are measured with the
experimental setup therefore there is no need of a scale and the experiment
price less than \pounds20 is mainly due to the batteries used. Multiplied
137~times, this experimental setup was given at the fourth open international
Experimental Physics Olympiad (EPO4) and a dozen high school students did very
well. This article, however, focuses on the catastrophe theory, which is the
basis of the methodology.


title: Parallel Evaluation of Multi-Semi-Joins

abstract:
  While services such as Amazon AWS make computing power abundantly available,
adding more computing nodes can incur high costs in, for instance,
pay-as-you-go plans while not always significantly improving the net running
time (aka wall-clock time) of queries. In this work, we provide algorithms for
parallel evaluation of SGF queries in MapReduce that optimize total time, while
retaining low net time. Not only can SGF queries specify all semi-join
reducers, but also more expressive queries involving disjunction and negation.
Since SGF queries can be seen as Boolean combinations of (potentially nested)
semi-joins, we introduce a novel multi-semi-join (MSJ) MapReduce operator that
enables the evaluation of a set of semi-joins in one job. We use this operator
to obtain parallel query plans for SGF queries that outvalue sequential plans
w.r.t. net time and provide additional optimizations aimed at minimizing total
time without severely affecting net time. Even though the latter optimizations
are NP-hard, we present effective greedy algorithms. Our experiments, conducted
using our own implementation Gumbo on top of Hadoop, confirm the usefulness of
parallel query plans, and the effectiveness and scalability of our
optimizations, all with a significant improvement over Pig and Hive.


title: Consecutive cancellations in Tor modules over local rings

abstract:
  Let $M, N$ be finite modules over a Noetherian local ring $R$, and let $G$ be
the associated graded ring of $R$. We show that the bigraded Hilbert series of
$gr(Tor^R(M,N))$ is obtained from that of $Tor^G(gr(M),gr(N))$ by negative
consecutive cancellations, thus extending a theorem of Rossi and Sharifan.


title: Virtuous smoothing for global optimization

abstract:
  In the context of global optimization and mixed-integer non-linear
programming, generalizing a technique of D'Ambrosio, Fampa, Lee and Vigerske
for handling the square-root function, we develop a virtuous smoothing method,
using cubics, aimed at functions having some limited non-smoothness. Our
results pertain to root functions ($w^p$ with $0<p<1$) and their increasing
concave relatives. We provide (i) a sufficient condition (which applies to
functions more general than root functions) for our smoothing to be increasing
and concave, (ii) a proof that when $p=1/q$ for integers $q\geq 2$, our
smoothing lower bounds the root function, (iii) substantial progress (i.e., a
proof for integers $2\leq q\leq 10,000$) on the conjecture that our smoothing
is a sharper bound on the root function than the natural and simpler "shifted
root function", and (iv) for all root functions, a quantification of the
superiority (in an average sense) of our smoothing versus the shifted root
function near 0.


title:
Canonical Horizontal Visibility Graphs are uniquely determined by their
  degree sequence

abstract:
  Horizontal visibility graphs (HVGs) are graphs constructed in correspondence
with number sequences that have been introduced and explored recently in the
context of graph-theoretical time series analysis. In most of the cases simple
measures based on the degree sequence (or functionals of these such as
entropies over degree and joint degree distributions) appear to be highly
informative features for automatic classification and provide nontrivial
information on the associated dynam- ical process, working even better than
more sophisticated topological metrics. It is thus an open question why these
seemingly simple measures capture so much information. Here we prove that,
under suitable conditions, there exist a bijection between the adjacency matrix
of an HVG and its degree sequence, and we give an explicit construction of such
bijection. As a consequence, under these conditions HVGs are unigraphs and the
degree sequence fully encapsulates all the information of these graphs, thereby
giving a plausible reason for its apparently unreasonable effectiveness.


title:
On the boosting ability of top-down decision tree learning algorithm for
  multiclass classification

abstract:
  We analyze the performance of the top-down multiclass classification
algorithm for decision tree learning called LOMtree, recently proposed in the
literature Choromanska and Langford (2014) for solving efficiently
classification problems with very large number of classes. The algorithm online
optimizes the objective function which simultaneously controls the depth of the
tree and its statistical accuracy. We prove important properties of this
objective and explore its connection to three well-known entropy-based decision
tree objectives, i.e. Shannon entropy, Gini-entropy and its modified version,
for which instead online optimization schemes were not yet developed. We show,
via boosting-type guarantees, that maximizing the considered objective leads
also to the reduction of all of these entropy-based objectives. The bounds we
obtain critically depend on the strong-concavity properties of the
entropy-based criteria, where the mildest dependence on the number of classes
(only logarithmic) corresponds to the Shannon entropy.


title: Visual TASK: A Collaborative Cognitive Aid for Acute Care Resuscitation

abstract:
  Preventable medical errors are a severe problem in healthcare, causing over
400,000 deaths per year in the US in hospitals alone. In acute care, the branch
of medicine encompassing the emergency department (ED) and intensive care units
(ICU), error rates may be higher to due low situational awareness among
clinicians performing resuscitation on patients. To support cognition, novice
team leaders may rely on reference guides to direct and anticipate future
steps. However, guides often act as a fixation point, diverting the leader's
attention away from the team. To address this issue, we conducted a qualitative
study that evaluates a collaborative cognitive aid co-designed with clinicians
called Visual TASK. Our study explored the use of Visual TASK in three
simulations employing a projected shared display with two different interaction
modalities: the Microsoft Kinect and a touchscreen. Our results suggest that
tools like the Kinect, while useful in other areas of acute care like the OR,
are unsuitable for use in high-stress situations like resuscitation. We also
observed that fixation may not be constrained to reference guides alone, and
may extend to other objects in the room. We present our findings, and a
discussion regarding future avenues in which collaborative cognitive aids may
help in improving situational awareness in resuscitation.


title: Control of reaction-diffusion equations on time-evolving manifolds

abstract:
  Among the main actors of organism development there are morphogens, which are
signaling molecules diffusing in the developing organism and acting on cells to
produce local responses. Growth is thus determined by the distribution of such
signal. Meanwhile, the diffusion of the signal is itself affected by the
changes in shape and size of the organism. In other words, there is a complete
coupling between the diffusion of the signal and the change of the shapes. In
this paper, we introduce a mathematical model to investigate such coupling. The
shape is given by a manifold, that varies in time as the result of a
deformation given by a transport equation. The signal is represented by a
density, diffusing on the manifold via a diffusion equation. We show the
non-commutativity of the transport and diffusion evolution by introducing a new
concept of Lie bracket between the diffusion and the transport operator. We
also provide numerical simulations showing this phenomenon.


title: On two-generator subgroups in SL_2(Z), SL_2(Q), and SL_2(R)

abstract:
  We consider what some authors call 'parabolic M\"obius subgroups' of matrices
over Z, Q, and R and focus on the membership problem in these subgroups and
complexity of relevant algorithms.


title:
Revisiting XOR-based Network Coding for Energy Efficient Broadcasting in
  Mobile Ad Hoc Networks

abstract:
  Network coding is commonly used to improve the energy efficiency of
network-wide broadcasting in wireless multi-hop networks. In this work, we
focus on XOR-based broadcasting in mobile ad hoc networks with multiple
sources. We make the observation that the common approach, which is to benefit
from the synergy of XOR network coding with a CDS-based broadcast algorithm,
suffers performance breakdowns. After delving into the details of this synergy,
we attribute this behavior to an important mechanism of the underlying
broadcast algorithm, known as the "termination criterion". To tackle the
problem, we propose a termination criterion that is fully compatible with XOR
coding. In addition to that, we revisit the internals of XOR coding. We first
enhance the synergy of XOR coding with the underlying broadcast algorithm by
allowing each mechanism to benefit from information available by the other. In
this way, we manage to improve the pruning efficiency of the CDS-based
algorithm while at the same time we come up with a method for detecting coding
opportunities that has minimal storage and processing requirements compared to
current approaches. Then, for the first time, we use XOR coding as a mechanism
not only for enhancing energy efficiency but also for reducing the
end-to-end-delay. We validate the effectiveness of our proposed algorithm
through extensive simulations on a diverse set of scenarios.


title: Lattice Model for water-solute mixtures

abstract:
  A lattice model for the study of mixtures of associating liquids is proposed.
Solvent and solute are modeled by adapting the associating lattice gas (ALG)
model. The nature of interaction solute/solvent is controlled by tuning the
energy interactions between the patches of ALG model. We have studied three set
of parameters, resulting on, hydrophilic, inert and hydrophobic interactions.
Extensive Monte Carlo simulations were carried out and the behavior of pure
components and the excess properties of the mixtures have been studied. The
pure components: water (solvent) and solute, have quite similar phase diagrams,
presenting: gas, low density liquid, and high density liquid phases. In the
case of solute, the regions of coexistence are substantially reduced when
compared with both the water and the standard ALG models. A numerical procedure
has been developed in order to attain series of results at constant pressure
from simulations of the lattice gas model in the grand canonical ensemble. The
excess properties of the mixtures: volume and enthalpy as the function of the
solute fraction have been studied for different interaction parameters of the
model. Our model is able to reproduce qualitatively well the excess volume and
enthalpy for different aqueous solutions. For the hydrophilic case, we show
that the model is able to reproduce the excess volume and enthalpy of mixtures
of small alcohols and amines. The inert case reproduces the behavior of large
alcohols such as, propanol, butanol and pentanol. For last case (hydrophobic),
the excess properties reproduce the behavior of ionic liquids in aqueous
solution.


title: Darbo-type theorem for quasimeasure of noncompactness

abstract:
  The paper introduces the concept of quasimeasure of noncompactness. Motivated
by the Arzel\`a-Ascoli theorem for $C^b(X,E)$, where $X$ is an Euclidean space
and $E$ an arbitrary Banach space, we construct a quasimeasure for this space
and study its properties. An analogon for Darbo fixed point theorem is obtained
with the additional aid of measure of nonconvexity. The paper ends with
possible application in integral equations. We prove that a Hammerstein
operator with Carath\'{e}odory kernel and nonlinearity of a certain type has a
fixed point.


title: Raman transitions between hyperfine clock states in a magnetic trap

abstract:
  We present our experimental investigation of an optical Raman transition
between the magnetic clock states of $^{87}$Rb in an atom chip magnetic trap.
The transfer of atomic population is induced by a pair of diode lasers which
couple the two clock states off-resonantly to an intermediate state manifold.
This transition is subject to destructive interference of two excitation paths,
which leads to a reduction of the effective two-photon Rabi-frequency.
Furthermore, we find that the transition frequency is highly sensitive to the
intensity ratio of the diode lasers. Our results are well described in terms of
light shifts in the multi-level structure of $^{87}$Rb. The differential light
shifts vanish at an optimal intensity ratio, which we observe as a narrowing of
the transition linewidth. We also observe the temporal dynamics of the
population transfer and find good agreement with a model based on the system's
master equation and a Gaussian laser beam profile. Finally, we identify several
sources of decoherence in our system, and discuss possible improvements.


title: The Non-uniform Fast Fourier Transform in Computed Tomography

abstract:
  This project is aimed at designing the fast forward projection algorithm and
also the backprojection algorithm for cone beam CT imaging systems with
circular X-ray source trajectory. The principle of the designs is based on
utilizing the potential computational efficiency which the Fourier Slice
Theorem and the Non-uniform Fast Fourier Transform (NUFFT) will bring forth. In
this Masters report, the detailed design of the NUFFT based forward projector
including a novel 3D (derivative of) Radon space resampling method will be
given. Meanwhile the complexity of the NUFFT based forward projector is
analysed and compared with the non-Fourier based CT projector, and the
advantage of the NUFFT based forward projection in terms of the computational
efficiency is demonstrated in this report. Base on the design of the forward
algorithm, the NUFFT based 3D direct reconstruction algorithm will be derived.
The experiments will be taken to test the performance of the forward algorithm
and the backprojection algorithm to show the practicability and accuracy of
these designs by comparing them jointly with the well-acknowledged cone beam CT
operators: the CT linear interpolation forward projector and the FDK algorithm.
This Master report will demonstrate a novel and efficient way of implementing
the cone beam CT operator, a detailed summary of the project, and the future
research prospects of the NUFFT based cone beam CT algorithms.


title: Switching in time-optimal problem. The 3-D case with 2-D control

abstract:
  We study local structure of time-optimal controls and trajectories for a
3-dimensional control-affine system with a 2-dimensional control parameter with
values in the disk. In particular, we give sufficient conditions, in terms of
Lie bracket relations, for optimal controls to be smooth or to have only
isolated jump discontinuities.


title: New Complexiton Solutions of the KdV and Coupled KdV Equations

abstract:
  A new approach to double-sub equation method is introduced to construct novel
solutions for the nonlinear partial differential equations. It is applied to
the Korteweg-de Vries (KdV) equation and yields new complexiton solutions of
both the KdV and coupled KdV equations. The graphs of the solutions are also
illustrated.


title:
An Energy-Aware Programming Approach for Mobile Application Development
  Guided by a Fine-Grained Energy Model

abstract:
  Energy efficiency has a significant influence on user experience of
battery-driven devices such as smartphones and tablets. It is shown that
software optimization plays an important role in reducing energy consumption of
system. However, in mobile devices, the conventional nature of compiler
considers not only energy-efficiency but also limited memory usage and
real-time response to user inputs, which largely limits the compiler's positive
impact on energy-saving. As a result, the code optimization relies more on
developers. In this paper, we propose an energy-aware programming approach,
which is guided by an operation-based source-code-level energy model. And this
approach is placed at the end of software engineering life cycle to avoid
distracting developers from guaranteeing the correctness of system. The
experimental result shows that our approach is able to save from 6.4% to 50.2%
of the overall energy consumption depending on different scenarios.


title:
PS1-14bj: A Hydrogen-Poor Superluminous Supernova With a Long Rise and
  Slow Decay

abstract:
  We present photometry and spectroscopy of PS1-14bj, a hydrogen-poor
superluminous supernova (SLSN) at redshift $z=0.5215$ discovered in the last
months of the Pan-STARRS1 Medium Deep Survey. PS1-14bj stands out by its
extremely slow evolution, with an observed rise of $\gtrsim 125$ rest-frame
days, and exponential decline out to $\sim 250$ days past peak at a measured
rate of $0.01~{\rm mag~day}^{-1}$, consistent with fully-trapped $^{56}$Co
decay. This is the longest rise time measured in a SLSN to date, and the first
SLSN to show a rise time consistent with pair-instability supernova (PISN)
models. Compared to other slowly-evolving SLSNe, it is spectroscopically
similar to the prototype SN2007bi at maximum light, though lower in luminosity
($L_{\rm peak} \simeq 4.6 \times 10^{43} {\rm erg s}^{-1}$) and with a flatter
peak than previous events. PS1-14bj shows a number of peculiar properties,
including a near-constant color temperature for $>200$ days past peak, and
strong emission lines from [O III] $\lambda$5007 and [O III] $\lambda$4363 with
a velocity width of $\sim$3400 km/s, in its late-time spectra. These both
suggest there is a sustained source of heating over very long timescales, and
are incompatible with a simple $^{56}$Ni-powered/PISN interpretation. A
modified magnetar model including emission leakage at late times can reproduce
the light curve, in which case the blue continuum and [O III] features are
interpreted as material heated and ionized by the inner pulsar wind nebula
becoming visible at late times. Alternatively, the late-time heating could be
due to interaction with a shell of H-poor circumstellar material.


title: Fast Concurrent Cuckoo Kick-Out Eviction Schemes for High-Density Tables

abstract:
  Cuckoo hashing guarantees constant-time lookups regardless of table density,
making it a viable candidate for high-density tables. Cuckoo hashing insertions
perform poorly at high table densities, however. In this paper, we mitigate
this problem through the introduction of novel kick-out eviction algorithms.
Experimentally, our algorithms reduce the number of bins viewed per insertion
for high-density tables by as much as a factor of ten.
  We also introduce an optimistic concurrency scheme for transactional
multi-writer cuckoo hash tables (not using hardware transactional memory). For
delete-light workloads, one of our kick-out algorithms avoids all competition
between insertions with high probability, and significantly reduces
transaction-abort frequency. This result is extended to arbitrary workloads
using a new synchronization mechanism called a claim flag.


title:
Irrelevance of Bell's Theorem for experiments involving correlations in
  space and time: a specific loophole-free computer-example

abstract:
  John Bell is generally credited to have accomplished the remarkable "proof"
that any theory of physics, which is both Einstein-local and "realistic"
(counterfactually definite), results in a strong upper bound to the
correlations that are measured in space and time. He thus predicts that
Einstein-Podolsky-Rosen experiments cannot violate Bell- type inequalities. We
present a counterexample to this claim, based on discrete-event computer
simulations. Our model-results fully agree with the predictions of quantum
theory for Einstein-Podolsky-Rosen-Bohm experiments and are free of the
detection- or a coincidence-loophole.


title:
Gromov-Witten theory of $\mathrm{K3} \times \mathbb{P}^1$ and
  quasi-Jacobi forms

abstract:
  Let $S$ be a K3 surface with primitive curve class $\beta$. We solve the
relative Gromov-Witten theory of $S \times \mathbb{P}^1$ in classes $(\beta,1)$
and $(\beta,2)$. The generating series are quasi-Jacobi forms and equal to a
corresponding series of genus $0$ Gromov-Witten invariants on the Hilbert
scheme of points of $S$. This proves a special case of a conjecture of
Pandharipande and the author. The new geometric input of the paper is a genus
bound for hyperelliptic curves on K3 surfaces proven by Ciliberto and Knutsen.
By exploiting various formal properties we find that a key generating series is
determined by the very first few coefficients.
  Let $E$ be an elliptic curve. As collorary of our computations we prove that
Gromov-Witten invariants of $S \times E$ in classes $(\beta,1)$ and $(\beta,2)$
are coefficients of the reciprocal of the Igusa cusp form. We also calculate
several linear Hodge integrals on the moduli space of stable maps to a K3
surface and the Gromov-Witten invariants of an abelian threefold in classes of
type $(1,1,d)$.


title:
Biologically Inspired Radio Signal Feature Extraction with Sparse
  Denoising Autoencoders

abstract:
  Automatic modulation classification (AMC) is an important task for modern
communication systems; however, it is a challenging problem when signal
features and precise models for generating each modulation may be unknown. We
present a new biologically-inspired AMC method without the need for models or
manually specified features --- thus removing the requirement for expert prior
knowledge. We accomplish this task using regularized stacked sparse denoising
autoencoders (SSDAs). Our method selects efficient classification features
directly from raw in-phase/quadrature (I/Q) radio signals in an unsupervised
manner. These features are then used to construct higher-complexity abstract
features which can be used for automatic modulation classification. We
demonstrate this process using a dataset generated with a software defined
radio, consisting of random input bits encoded in 100-sample segments of
various common digital radio modulations. Our results show correct
classification rates of > 99% at 7.5 dB signal-to-noise ratio (SNR) and > 92%
at 0 dB SNR in a 6-way classification test. Our experiments demonstrate a
dramatically new and broadly applicable mechanism for performing AMC and
related tasks without the need for expert-defined or modulation-specific signal
information.


title:
Permutational behavior of reversed Dickson polynomials over finite
  fields

abstract:
  In this paper, we use the method developed previously by Hong, Qin and Zhao
to obtain several results on the permutational behavior of the reversed Dickson
polynomial $D_{n,k}(1,x)$ of the $(k+1)$-th kind over the finite field
${\mathbb F}_{q}$. Particularly, we present the explicit evaluation of the
first moment $\sum_{a\in {\mathbb F}_{q}}D_{n,k}(1,a)$. Our results extend the
known results from the case $0\le k\le 3$ to the general $k\ge 0$ case.


title:
$<X_{max}>$ Uncertainty from Extrapolation of Cosmic Ray Air Shower
  Parameters

abstract:
  Recent measurements at the LHC of the p-p total cross section have reduced
the uncertainty in simulations of cosmic ray air showers. In particular of the
depth of shower maximum, called $X_{max}$. However, uncertainties of other
important parameters, in particular the multiplicity and elasticity of high
energy interactions, have not improved, and there is a remaining uncertainty
due to the total cross section. Uncertainties due to extrapolations from
accelerator data, at a maximum energy of $\sim$ one TeV in the p-p center of
mass, to 250 TeV ($3\times10^{19}$ eV in a cosmic ray proton's lab frame)
introduce significant uncertainties in predictions of $<X_{max}>$. In this
paper we estimate a lower limit on these uncertainties. The result is that the
uncertainty in $<X_{max}>$ is larger than the difference among the modern
models being used in the field. At the full energy of the LHC, which is
equivalent to $\sim 1\times10^{17}$ eV in the cosmic ray lab frame, the
extrapolation is not as extreme, and the uncertainty is approximately equal to
the difference among the models.


title:
How the instant collapse of a spatially-extended quantum state is
  consistent with relativity of simultaneity

abstract:
  A thought experiment is considered on observation of instantaneous collapse
of an extended wave packet. According to relativity of simultaneity, such a
collapse being instantaneous in some reference frame must be a lasting process
in other frames. But according to quantum mechanics, collapse is instantaneous
in any frame. Mathematical structure of quantum mechanics eliminates any
contradictions between these two apparently conflicting statements. Here the
invariance of quantum-mechanical collapse is shown to follow directly from the
Born postulate, without any use of mathematical properties of quantum
operators. The consistency of quantum mechanics with Relativity is also shown
for instant disentanglement of a composite system.


title: Fokker-Planck formalism in magnetic resonance simulations

abstract:
  This paper presents an overview of the Fokker-Planck formalism for
non-biological magnetic resonance simulations, describes its existing
applications and proposes some novel ones. The most attractive feature of
Fokker-Planck theory compared to the commonly used Liouville - von Neumann
equation is that, for all relevant types of spatial dynamics (spinning,
diffusion, flow, etc.), the corresponding Fokker-Planck Hamiltonian is
time-independent. Many difficult NMR, EPR and MRI simulation problems (multiple
rotation NMR, ultrafast NMR, gradient-based zero-quantum filters, diffusion and
flow NMR, off-resonance soft microwave pulses in EPR, spin-spin coupling
effects in MRI, etc.) are simplified significantly in Fokker-Planck space. The
paper also summarises the author's experiences with writing and using the
corresponding modules of the Spinach library - the methods described below have
enabled a large variety of simulations previously considered too complicated
for routine practical use.


title:
Discrimination of nuclear and electronic recoil events using plasma
  effect in germanium detectors

abstract:
  We report a new method of using the plasma time difference, which results
from the plasma effect, between the nuclear and electronic recoil events in
high-purity germanium detectors to distinguish these two types of events in the
search for rare physics processes. The physics mechanism of the plasma effect
is discussed in detail. A numerical model is developed to calculate the plasma
time for nuclear and electronic recoils at various energies in germanium
detectors. It can be shown that under certain conditions the plasma time
difference is large enough to be observable. The experimental aspects in
realizing such a discrimination in germanium detectors is discussed.


title:
On the kernel and particle consistency in smoothed particle
  hydrodynamics

abstract:
  The problem of consistency of smoothed particle hydrodynamics (SPH) has
demanded considerable attention in the past few years due to the ever
increasing number of applications of the method in many areas of science and
engineering. A loss of consistency leads to an inevitable loss of approximation
accuracy. In this paper, we revisit the issue of SPH kernel and particle
consistency and demonstrate that SPH has a limiting second-order convergence
rate. Numerical experiments with suitably chosen test functions validate this
conclusion. In particular, we find that when using the root mean square error
as a model evaluation statistics, well-known corrective SPH schemes, which were
thought to converge to second, or even higher order, are actually first-order
accurate, or at best close to second order. We also find that observing the
joint limit when $N\to\infty$, $h\to 0$, and $n\to\infty$, as was recently
proposed by Zhu et al., where $N$ is the total number of particles, $h$ is the
smoothing length, and $n$ is the number of neighbor particles, standard SPH
restores full $C^{0}$ particle consistency for both the estimates of the
function and its derivatives and becomes insensitive to particle disorder.

categories: math.NA astro-ph.CO astro-ph.GA physics.comp-ph physics.flu-dyn


title:
Classical Equation of Electromagnetic Field in the Higgs Boson Field and
  Estimation on the Static Electrical Polarizability of Leptons

abstract:
  In our paper we derived the classical motion equation of electromagnetic
field in space with Higgs field and by means of it discussed the distributions
of charge and current formed when the static electrical and magnetic fields are
interacting with the spherically symmetrical Higgs field, and predicted the
electrical polarizability of electron.


title:
Heart Rate Variability and Respiration Signal as Diagnostic Tools for
  Late Onset Sepsis in Neonatal Intensive Care Units

abstract:
  Apnea-bradycardia is one of the major clinical early indicators of late-onset
sepsis occurring in approximately 7% to 10% of all neonates and in more than
25% of very low birth weight infants in NICU. The objective of this paper was
to determine if HRV, respiration and their relationships help to diagnose
infection in premature infants via non-invasive ways in NICU. Therefore, we
implement Mono-Channel (MC) and Bi-Channel (BC) Analysis in two groups: sepsis
(S) vs. non-sepsis (NS). Firstly, we studied RR series not only by linear
methods: time domain and frequency domain, but also by non-linear methods:
chaos theory and information theory. The results show that alpha Slow, alpha
Fast and Sample Entropy are significant parameters to distinguish S from NS.
Secondly, the question about the functional coupling of HRV and nasal
respiration is addressed. Local linear correlation coefficient r2t,f has been
explored, while non-linear regression coefficient h2 was calculated in two
directions. It is obvious that r2t,f within the third frequency band (0.2<f<0.4
Hz) and h2 in two directions were complementary approaches to diagnose sepsis.
Thirdly, feasibility study is carried out on the candidate parameters selected
from MC and BC respectively. We discovered that the proposed test based on
optimal fusion of 6 features shows good performance with the largest AUC and a
reduced probability of false alarm (PFA).


title: Integral Van Vleck's and Kannappan's functional equations on semigroups

abstract:
  In this paper we study the solutions of the integral Van Vleck's functional
equation for the sine $$\int_{S}f(x\tau(y)t)d\mu(t)-\int_{S}f(xyt)d\mu(t)
=2f(x)f(y),\; x,y\in S$$ and the integral Kannappan's functional equation
$$\int_{S}f(xyt)d\mu(t)+\int_{S}f(x\tau(y)t)d\mu(t) =2f(x)f(y),\; x,y\in S,$$
where $S$ is a semigroup, $\tau$ is an involution of $S$ and $\mu$ is a measure
that is linear combinations of point measures $(\delta_{z_{i}})_{i\in I}$, such
that for all $i\in I$, $z_{i}$ is contained in the center of $S$. \\ We express
the solutions of the first equation by means of multiplicative functions on
$S$, and we prove that the solutions of the second equation are closely related
to the solutions of the classic d'Alembert's functional equation with
involution.


title: Generalized solutions of the Dirac equation, W bosons, and beta decay

abstract:
  We study the 7x7 Hagen-Hurley equations describing spin 1 particles. We split
these equations, in the interacting case, into two Dirac equations with
non-standard solutions. It is argued that these solutions describe decay of a
virtual W boson in beta decay.


title: The Volumetric Rate of Superluminous Supernovae at z~1

abstract:
  We present a measurement of the volumetric rate of superluminous supernovae
(SLSNe) at z~1, measured using archival data from the first four years of the
Canada-France-Hawaii Telescope Supernova Legacy Survey (SNLS). We develop a
method for the photometric classification of SLSNe to construct our sample. Our
sample includes two previously spectroscopically-identified objects, and a
further new candidate selected using our classification technique. We use the
point-source recovery efficiencies from Perrett et.al. (2010) and a Monte Carlo
approach to calculate the rate based on our SLSN sample. We find that the three
identified SLSNe from SNLS give a rate of 91 (+76/-36) SNe/Yr/Gpc^3 at a
volume-weighted redshift of z=1.13. This is equivalent to 2.2 (+1.8/-0.9)
x10^-4 of the volumetric core collapse supernova rate at the same redshift.
When combined with other rate measurements from the literature, we show that
the rate of SLSNe increases with redshift in a manner consistent with that of
the cosmic star formation history. We also estimate the rate of ultra-long
gamma ray bursts (ULGRBs) based on the events discovered by the Swift
satellite, and show that it is comparable to the rate of SLSNe, providing
further evidence of a possible connection between these two classes of events.
We also examine the host galaxies of the SLSNe discovered in SNLS, and find
them to be consistent with the stellar-mass distribution of other published
samples of SLSNe.


title: Graph reconstruction from the observation of diffused signals

abstract:
  Signal processing on graphs has received a lot of attention in the recent
years. A lot of techniques have arised, inspired by classical signal processing
ones, to allow studying signals on any kind of graph. A common aspect of these
technique is that they require a graph correctly modeling the studied support
to explain the signals that are observed on it. However, in many cases, such a
graph is unavailable or has no real physical existence. An example of this
latter case is a set of sensors randomly thrown in a field which obviously
observe related information. To study such signals, there is no intuitive
choice for a support graph. In this document, we address the problem of
inferring a graph structure from the observation of signals, under the
assumption that they were issued of the diffusion of initially i.i.d. signals.
To validate our approach, we design an experimental protocol, in which we
diffuse signals on a known graph. Then, we forget the graph, and show that we
are able to retrieve it very precisely from the only knowledge of the diffused
signals.


title: Some Inverse Spectral Results in Exterior Transmission Problem

abstract:
  We consider an inverse spectral theory in a domain with the cavity that is
bounded by a penetrable inhomogeneous medium. An ODE system is constructed
piecewise through the solutions inside and outside the cavity. The ODE system
is connected to the PDE system via the analytic continuation. For each
scattered angle, we describe its eigenvalue density in the complex plane, and
prove an inverse uniqueness on the inhomogeneity by the measurements in the
far-fields.


title: A Near-Field Basis in Radially Symmetric Interior Transmission Problem

abstract:
  The spectrum of interior transmission problem is the zero set of certain
entire functional determinant. It is classic that we deploy the series of
exponential polynomials to approximate the distribution of the roots of the
entire functions of exponential type. We construct an exponential system in the
form of $\{e^{ik_jr}\}$ according to the set of interior transmission
eigenvalues $\{k_{j}\}$. The eigenvalues are the zeros of a sine-type function.
In particular, they are intersection points of two asymptotically periodic
entire functions. The intersection set is asymptotically sine-like near the
real axis, so we may manage to construct a basis according to the class of
spectral objects. Due to the result of Paley-Wiener theorem, the zero set
generates a natural duality in the form of Fourier transform associated with
exponential polynomials. Whenever there is a sufficient quantity of
transmission eigenvalues, we are given a series of exponential polynomials to
saturate the functional density, which completes a $L^{2}$-Riesz basis in a
suitable ball.


title:
There is no direct generalization of positive partial transpose
  criterion to the three-by-three case

abstract:
  We show that there cannot exist a straightforward generalization of the
famous positive partial transpose criterion to three-by-three systems. We call
straightforward generalizations that use a finite set of positive maps and
arbitrary local rotations of the tested two-partite state. In particular, we
show that a family of extreme positive maps discussed in a paper by Ha and Kye,
cannot be replaced by a finite set of witnesses in the task of entanglement
detection in three-by-three systems. In a more mathematically elegant parlance,
our result says that the convex cone of positive maps of the set of
three-dimensional matrices into itself is not finitely generated as a mapping
cone


title: Star-shaped Oscillations of Leidenfrost Drops

abstract:
  We experimentally investigate the self-sustained, star-shaped oscillations of
Leidenfrost drops. The drops levitate on a cushion of evaporated vapor over a
heated, curved surface. We observe modes with $n = 2-13$ lobes around the drop
periphery. We find that the wavelength of the oscillations depends only on the
capillary length of the liquid, and is independent of the drop radius and
substrate temperature. However, the number of observed modes depends
sensitively on the liquid viscosity. The dominant frequency of pressure
variations in the vapor layer is approximately twice the drop oscillation
frequency, consistent with a parametric forcing mechanism. Our results show
that the star-shaped oscillations are driven by capillary waves of a
characteristic wavelength beneath the drop, and that the waves are generated by
a large shear stress at the liquid-vapor interface.


title: A Metric for Heterotic Moduli

abstract:
  Heterotic vacua of string theory are realised, at large radius, by a compact
threefold with vanishing first Chern class together with a choice of stable
holomorphic vector bundle. These form a wide class of potentially realistic
four-dimensional vacua of string theory. Despite all their phenomenological
promise, there is little understanding of the metric on the moduli space of
these. What is sought is the analogue of special geometry for these vacua. The
metric on the moduli space is important in phenomenology as it normalises
D-terms and Yukawa couplings. It is also of interest in mathematics, since it
generalises the metric, first found by Kobayashi, on the space of gauge field
connections, to a more general context. Here we construct this metric, correct
to first order in alpha', in two ways: first by postulating a metric that is
invariant under background gauge transformations of the gauge field, and also
by dimensionally reducing heterotic supergravity. These methods agree and the
resulting metric is Kahler, as is required by supersymmetry. Checking that the
metric is in fact Kahler is quite intricate and uses the anomaly cancellation
equation for the H-field, in an essential way. The Kahler potential
nevertheless takes a remarkably simple form: it is Kahler potential for special
geometry with the Kahler form replaced by the alpha'-corrected hermitian form.


title:
An Inverse Uniqueness of a Phaseless Scattering Problem by
  Zero-Crossings

abstract:
  We discuss the inverse uniqueness problem in phaseless scattering by counting
the zeros of its modulus of the scattering amplitude. The phase linearization
of scattered wave field disturbs the originally uniform distribution of the
zero set. There is a connection between the perturbation of the index of
refraction and the zero distribution of the modulus. We conclude the inverse
uniqueness of the phaseless problem from the point of view of interior
transmission problem.


title:
Real-time Eye Gaze Direction Classification Using Convolutional Neural
  Network

abstract:
  Estimation eye gaze direction is useful in various human-computer interaction
tasks. Knowledge of gaze direction can give valuable information regarding
users point of attention. Certain patterns of eye movements known as eye
accessing cues are reported to be related to the cognitive processes in the
human brain. We propose a real-time framework for the classification of eye
gaze direction and estimation of eye accessing cues. In the first stage, the
algorithm detects faces using a modified version of the Viola-Jones algorithm.
A rough eye region is obtained using geometric relations and facial landmarks.
The eye region obtained is used in the subsequent stage to classify the eye
gaze direction. A convolutional neural network is employed in this work for the
classification of eye gaze direction. The proposed algorithm was tested on Eye
Chimera database and found to outperform state of the art methods. The
computational complexity of the algorithm is very less in the testing phase.
The algorithm achieved an average frame rate of 24 fps in the desktop
environment.


title:
The resolvent algebra for oscillating lattice systems: Dynamics, ground
  and equilibrium states

abstract:
  Within the C*-algebraic framework of the resolvent algebra for canonical
quantum systems, the structure of oscillating lattice systems with bounded
nearest neighbor interactions is studied in any number of dimensions. The
global dynamics of such systems acts on the resolvent algebra by automorphisms
and there exists a (in any regular representation) weakly dense subalgebra on
which this action is pointwise norm continuous. Based on this observation,
equilibrium (KMS) states as well as ground states are constructed which are
shown to be regular. It is also indicated how to deal with singular
interactions and non-harmonic oscillations.

categories: math-ph cond-mat.stat-mech math.MP math.OA quant-ph


title: Quantum State Transfer on Coronas

abstract:
  We study state transfer in quantum walk on graphs relative to the adjacency
matrix. Our motivation is to understand how the addition of pendant subgraphs
affect state transfer. For two graphs $G$ and $H$, the Frucht-Harary corona
product $G \circ H$ is obtained by taking $|G|$ copies of the cone $K_{1} + H$
and by connecting the conical vertices according to $G$. Our work explores
conditions under which the corona $G \circ H$ exhibits state transfer. We also
describe new families of graphs with state transfer based on the corona
product. Some of these constructions provide a generalization of related known
results.