title:
Rest-frame ultra-violet spectra of massive galaxies at z=3: evidence of
  high-velocity outflows

abstract:
  Galaxy formation models invoke the presence of strong feedback mechanisms
that regulate the growth of massive galaxies at high redshifts. In this paper
we aim to: (1) confirm spectroscopically the redshifts of a sample of massive
galaxies selected with photometric redshifts z > 2.5; (2) investigate the
properties of their stellar and interstellar media; (3) detect the presence of
outflows, and measure their velocities. To achieve this, we analysed deep,
high-resolution (R~2000) FORS2 rest-frame UV spectra for 11 targets. We
confirmed that 9 out of 11 have spectroscopic redshifts z > 2.5. We also
serendipitously found two mask fillers at redshift z > 2.5, which originally
were assigned photometric redshifts 2.0 < z < 2.5. In the four highest-quality
spectra we derived outflow velocities by fitting the absorption line profiles
with models including multiple dynamical components. We found strongly
asymmetric, high-ionisation lines, from which we derived outflow velocities
ranging from 480 to 1518 km/s. The two galaxies with highest velocity show
signs of AGN. We revised the spectral energy distribution fitting U-band
through 8 micron photometry, including the analysis of a power-law component
subtraction to identify the possible presence of active galactic nuclei (AGN).
The revised stellar masses of all but one of our targets are >1e10 Msun, with
four having stellar masses > 5e10 Msun. Three galaxies have a significant
power-law component in their spectral energy distributions, which indicates
that they host AGN. We conclude that massive galaxies are characterised by
significantly higher velocity outflows than the typical Lyman break galaxies at
z ~ 3. The incidence of high-velocity outflows (~40% within our sample) is also
much higher than among massive galaxies at z < 1, which is consistent with the
powerful star formation and nuclear activity that most massive galaxies display
at z > 2.


title:
Multi-Frequency Optical-Depth Maps and the Case for Free-Free Absorption
  in Two Compact Symmetric Radio Sources: the CSO candidate J1324+4048 and the
  CSO J0029+3457

abstract:
  We obtained dual-polarization VLBI observations at six frequencies of the
compact symmetric object J0029+3457 and the CSO candidate J1324+4048. By
comparing the three lower-frequency maps with extrapolations of the high
frequency maps we produced maps of the optical depth as a function of
frequency. The morphology of the optical-depth maps of J1324+4048 is strikingly
smooth, suggestive of a foreground screen of absorbing gas. The spectra at the
intensity peaks fit a simple free-free absorption model, with a reduced chi
square ~ 2, better than a simple synchrotron self-absorption model, in which
the reduced chi square ~ 3.5 - 5.5. We conclude that the case for free-free
absorption in J1324+4048 is strong. The optical-depth maps of J0029+3457
exhibit structure, but the morphology does not correlate with that in the
intensity maps. The fit of the spectra at the peaks to a simple free-free
absorption model yields a reduced chi square ~ 1, but since the turnover is
gradual the fit is relatively insensitive to the input parameters. We find that
free-free absorption by a thin amount of gas in J0029+3457 is likely, but not
definitive. One compact feature in J0029+3457 has an inverted spectrum even at
the highest frequencies. We infer this to be the location of the core and
estimate an upper limit to the magnetic field of order 3 Gauss at a radius of
order 1 pc. In comparison with maps from observations at earlier epochs, no
apparent growth in either J1324+4048 or J0029+3457 is apparent, with upper
limits of 0.03 and 0.02 mas per yr, corresponding to maximum linear separation
speeds of 0.6c and 0.4c.


title: Automated and Weighted Self-Organizing Time Maps

abstract:
  This paper proposes schemes for automated and weighted Self-Organizing Time
Maps (SOTMs). The SOTM provides means for a visual approach to evolutionary
clustering, which aims at producing a sequence of clustering solutions. This
task we denote as visual dynamic clustering. The implication of an automated
SOTM is not only a data-driven parametrization of the SOTM, but also the
feature of adjusting the training to the characteristics of the data at each
time step. The aim of the weighted SOTM is to improve learning from more
trustworthy or important data with an instance-varying weight. The schemes for
automated and weighted SOTMs are illustrated on two real-world datasets: (i)
country-level risk indicators to measure the evolution of global imbalances,
and (ii) credit applicant data to measure the evolution of firm-level credit
risks.


title:
Dark Matter or Neutrino recoil? Interpretation of Recent Experimental
  Results

abstract:
  The elastic nuclear recoil signal, being under intense scrutiny by multiple
underground experiments, can be interpreted either as coming from the
interaction of nuclei with WIMP dark matter or from the scattering of new
species of MeV-energy neutrinos. The most promising model for the latter case
is a neutrino $\nu_b$ that interacts with baryon number, and with a flux
sourced by the oscillations of regular solar $^8$B neutrinos. We re-analyze
this model in light of the latest experimental results. In contrast to the
light-DM interpretation of various tentative positive signals (anomalies) that
is now seriously challenged by the negative results of the LUX experiment, the
neutrino interpretation remains a viable explanation to most of the anomalies.
Considering future prospects, we show that the superCDMS experiment alone, when
equipped with Ge and Si detectors, will be able to detect $\nu_b$ and
discriminate the model from a light DM interpretation. In addition, we also
provide the forecast for the new CRESST-II run that now operates with new
detectors and diminished backgrounds.


title:
Text Classification and Distributional features techniques in Datamining
  and Warehousing

abstract:
  Text Categorization is traditionally done by using the term frequency and
inverse document frequency.This type of method is not very good because, some
words which are not so important may appear in the document .The term frequency
of unimportant words may increase and document may be classified in the wrong
category.For reducing the error of classifying of documents in wrong category.
The Distributional features are introduced. In the Distribuional Features, the
Distribution of the words in the whole document is analyzed. Whole Document is
very closely analyzed for different measures like FirstAppearence, Last
Appearance, Centriod, Count, etc.The measures are calculated and they are used
in tf*idf equation and result is used in k- nearest neighbor and K-means
algorithm for classifying the documents.


title:
A complexity measure based method for studying the dependence of 222Rn
  concentration time series on indoor air temperature and humidity

abstract:
  We have suggested a complexity measure based method for studying the
dependence of measured 222Rn concentration time series on indoor air
temperature and humidity. This method is based on the Kolmogorov complexity
(KL). We have introduced (i) the sequence of the KL, (ii) the Kolmogorov
complexity highest value in the sequence (KLM) and (iii) the KL of the product
of time series. The noticed loss of the KLM complexity of 222Rn concentration
time series can be attributed to the indoor air humidity that keeps the radon
daughters in air.


title:
Spin-Wave Resonance Model of Surface Pinning in Ferromagnetic
  Semiconductor (Ga,Mn)As Thin Films

abstract:
  The source of spin-wave resonance (SWR) in thin films of the ferromagnetic
semiconductor (Ga,Mn)As is still under debate: does SWR stem from the
\emph{surface} anisotropy (in which case the surface inhomogeneity (SI) model
would apply), or does it originate in the \emph{bulk} inhomogeneity of the
magnetic structure of the sample (and thus requires the use of the volume
inhomogeneity (VI) model)? This paper outlines the ground on which the
controversy arose and shows why in different conditions a resonance sample may
meet the assumptions of either the SI or the VI model. In our considerations we
refer to the SWR spectra measured by Furdyna's team [X. Liu \textit{et al.},
Physical Review B \textbf{75}, 195220 (2007)] in (Ga,Mn)As thin films in
different configurations of the static magnetic field $\vec{H}$ with respect to
the surface. We demonstrate that the observed configuration dependence of the
SWR spectrum of the studied material can be described with the use of the
surface pinning parameter.


title: An RKHS Approach to Estimation with Sparsity Constraints

abstract:
  The investigation of the effects of sparsity or sparsity constraints in
signal processing problems has received considerable attention recently.
Sparsity constraints refer to the a priori information that the object or
signal of interest can be represented by using only few elements of a
predefined dictionary. Within this thesis, sparsity refers to the fact that a
vector to be estimated has only few nonzero entries. One specific field
concerned with sparsity constraints has become popular under the name
Compressed Sensing (CS). Within CS, the sparsity is exploited in order to
perform (nearly) lossless compression. Moreover, this compression is carried
out jointly or simultaneously with the process of sensing a physical quantity.
In contrast to CS, one can alternatively use sparsity to enhance signal
processing methods. Obviously, sparsity constraints can only improve the
obtainable estimation performance since the constraints can be interpreted as
an additional prior information about the unknown parameter vector which is to
be estimated. Our main focus will be on this aspect of sparsity, i.e., we
analyze how much we can gain in estimation performance due to the sparsity
constraints.


title:
An Exact, Time-Independent Approach to Clone Size Distributions in
  Normal and Mutated Cells

abstract:
  Biological tools such as genetic lineage tracing, three dimensional confocal
microscopy and next generation DNA sequencing are providing new ways to
quantify the distribution of clones of normal and mutated cells.
Population-wide clone size distributions in vivo are complicated by multiple
cell types, and overlapping birth and death processes. This has led to the
increased need for mathematically informed models to understand their
biological significance. Standard approaches usually require knowledge of
clonal age. We show that modelling on clone size independent of time is an
alternative method that offers certain analytical advantages; it can help
parameterize these models, and obtain distributions for counts of mutated or
proliferating cells, for example. When applied to a general birth-death process
common in epithelial progenitors this takes the form of a gamblers ruin
problem, the solution of which relates to counting Motzkin lattice paths.
Applying this approach to mutational processes, an alternative, exact,
formulation of the classic Luria Delbruck problem emerges. This approach can be
extended beyond neutral models of mutant clonal evolution, and also describe
some distributions relating to sub-clones within a tumour. The approaches above
are generally applicable to any Markovian branching process where the dynamics
of different "coloured" daughter branches are of interest.


title:
A standard format and a graphical user interface for spin system
  specification

abstract:
  We introduce a simple and general XML format for spin system description that
is the result of extensive consultations within Magnetic Resonance community
and unifies under one roof all major existing spin interaction specification
conventions. The format is human-readable, easy to edit and easy to parse using
standard XML libraries. We also describe a graphical user interface that was
designed to facilitate construction and visualization of complicated spin
systems. The interface is capable of generating input files for several popular
spin dynamics simulation packages.

categories: quant-ph math-ph math.MP physics.chem-ph


title:
Coherent emission of $\gamma $ quanta by synchrotron radiation excited
  nuclei: geometry of nearly backward scattering

abstract:
  A possibility of further development of Synchrotron M\"{o}ssbauer Source
(SMS) of $^{57}$Fe 14.4 keV radiation is considered. The principles and
detailed description of the SMS device is given in Refs. Phys. Rev. A 84,
053851 (2011) G. V. Smirnov et al, J. Synchrotron Rad., v. 19, 559 (2012) V.
Potapkin et al. The perfect crystal of Iron Borate, FeBO$_{3}$, is the central
element of this device. The coherent nuclear fluorescence of IB crystal
illuminated by synchrotron radiation produces the sharply directed beam of 14.4
keV M\"{o}ssbauer radiation from the crystal set at the pure nuclear Bragg
reflection. Up to now the low angle scattering geometry was used for generation
of the coherent $\gamma $ radiation. The analysis performed in the present
paper shows that the source of about two times larger power can be obtained
when nearly backward scattering geometry is employed. This result can be
efficiently applied in development of high resolution spectroscopy using
synchrotron radiation.


title:
MOSAIC_SSD: a new web-tool for the Species Sensitivity Distribution,
  allowing to include censored data by maximum likelihood

abstract:
  Censored data are seldom taken into account in Species Sensitivity
Distribution (SSD) analysis. However, they are found in virtually every dataset
and sometimes represent the better part of the data. Stringent recommendations
on data quality often lead to discard a lot of this meaningful data, often
resulting in datasets of reduced size, which lack representativeness of any
realistic community. However, it is reasonably simple to include censored data
into SSD by using an extension of the standard maximum likelihood method. In
this paper, we detail this approach based on the use of the R-package
\emph{fitdistrplus}, dedicated to the fit of parametric probability
distributions. In particular, we introduce the new web-tool MOSAIC$\_$SSD to
fit an SSD on datasets containing any kind of data, censored or not.
MOSAIC$\_$SSD allows predicting any Hazardous Concentration (HC) and provides
in addition bootstrap confidence intervals on the prediction. In the end,
taking examples from published data, we illustrate the added value of including
censored data in SSD.


title:
An alternative subtraction scheme for NLO QCD calculations using
  Nagy-Soper dipoles

abstract:
  In this work, we briefly report on the current status of an alternative
subtraction scheme which is based on the splitting kernels of an improved
parton shower prescription. Our focus is here on more recent developments as
well as generic arguments on the scaling behaviour.


title: When does third order efficiency imply fourth order efficiency

abstract:
  In this article third and fourth order efficiency are studied in the
framework of translation equivariant location estimators. We assume
$X_1,...,X_n$ i.i.d. $f(\cdot -\theta)$. By recognizing that equality in a
special form of the Cauchy-Schwarz inequality leads to a certain dependence of
the cumulants of the maximum likelihood estimator (MLE) for $\theta$, it is
shown that this MLE is fourth order efficient if the underlying distribution is
Gumbel. Contrary to similar results which were previously published this result
is not based on symmetry.


title:
$L^p$-estimates for a transmission problem of mixed elliptic-parabolic
  type

abstract:
  We consider the situation when an elliptic problem in a subdomain $\Omega_1$
of an $n$-dimensional bounded domain $\Omega$ is coupled via inhomogeneous
canonical transmission conditions to a parabolic problem in
$\Omega\setminus\Omega_1$. In particular, we can treat elliptic-parabolic
equations in bounded domains with discontinuous coefficients. Using Fourier
multiplier techniques, we prove an a priori estimate for strong solutions to
the equations in $L^p$-Sobolev spaces.


title: Extreme events in excitable systems and mechanisms of their generation

abstract:
  We study deterministic systems, composed of excitable units of
FitzHugh-Nagumo type, that are capable of self-generating and self-terminating
strong deviations from their regular dynamics without the influence of noise or
parameter change. These deviations are rare, short-lasting, and recurrent and
can therefore be regarded as extreme events. Employing a range of methods we
analyze dynamical properties of the systems, identifying features in the
systems' dynamics that may qualify as precursors to extreme events. We
investigate these features and elucidate mechanisms that may be responsible for
the generation of the extreme events.


title:
Exact simulation of the sample paths of a diffusion with a finite
  entrance boundary

abstract:
  Diffusion processes arise in many fields, and so simulating the path of a
diffusion is an important problem. It is usually necessary to make some sort of
approximation via model-discretization, but a recently introduced class of
algorithms, known as the exact algorithm and based on retrospective rejection
sampling ideas, obviate the need for such discretization. In this paper I
extend the exact algorithm to apply to a class of diffusions with a finite
entrance boundary. The key innovation is that for these models the Bessel
process is a more suitable candidate process than the more usually chosen
Brownian motion. The algorithm is illustrated by an application to a general
diffusion model of population growth, where it simulates paths efficiently,
while previous algorithms are impracticable.


title: Normal holonomy of CR submanifolds

abstract:
  We study the normal holonomy group, i.e. the holonomy group of the normal
connection, of a CR-submanifold of a complex space form. We complete the local
classification of normal holonomies for complex submanifolds. We show that the
normal holonomy group of a coisotropic submanifold acts as the holonomy
representation of a Riemannian symmetric space. In case of a totally real
submanifold we give two results about reduction of codimension. We describe
explicitly the action of the normal holonomy in the case in which the totally
real submanifold is contained in a totally real totally geodesic submanifold.
In such a case we prove the compactness of the normal holonomy group.


title: Particle acceleration by shocks in supernova remnants

abstract:
  Particle acceleration occurs on a range of scales from AU in the heliosphere
to Mpc in clusters of galaxies and to energies ranging from MeV to EeV. A
number of acceleration processes have been proposed, but diffusive shock
acceleration (DSA) is widely invoked as the predominant mechanism. DSA operates
on all these scales and probably to the highest energies. DSA is simple, robust
and predicts a universal spectrum. However there are still many unknowns
regarding particle acceleration. This paper focuses on the particular question
of whether supernova remnants (SNR) can produce the Galactic CR spectrum up to
the knee at a few PeV. The answer depends in large part on the detailed physics
of diffusive shock acceleration.


title: Representations of classical Lie groups and quantized free convolution

abstract:
  We study the decompositions into irreducible components of tensor products
and restrictions of irreducible representations of classical Lie groups as the
rank of the group goes to infinity. We prove the Law of Large Numbers for the
random counting measures describing the decomposition. This leads to two
operations on measures which are deformations of the notions of the free
convolution and the free projection. We further prove that if one replaces
counting measures with others coming from the work of Perelomov and Popov on
the higher order Casimir operators for classical groups, then the operations on
the measures turn into the free convolution and projection themselves.
  We also explain the relation between our results and limit shape theorems for
uniformly random lozenge tilings with and without axial symmetry.


title: Compact electron acceleration and bunch compression in THz waveguides

abstract:
  We numerically investigate the acceleration and bunch compression
capabilities of 20 mJ, 0.6 THz-centered coherent terahertz pulses in optimized
metallic dielectric-loaded cylindrical waveguides. In particular, we
theoretically demonstrate the acceleration of 1.6 pC and 16 pC electron bunches
from 1 MeV to 10 MeV over an interaction distance of 20mm, the compression of a
1.6 pC 1 MeV bunch from 100 fs to 2 fs (50 times compression) over an
interaction distance of about 18mm, and the compression of a 1.6 pC 10 MeV
bunch from 100 fs to 1.61 fs (62 times) over an interaction distance of 42 cm.
The obtained results show the promise of coherent THz pulses in realizing
compact electron acceleration and bunch compression schemes.


title:
Optimal preconditioning for the symmetric and non-symmetric coupling of
  adaptive finite elements and boundary elements

abstract:
  We analyze a multilevel diagonal additive Schwarz preconditioner for the
adaptive coupling of FEM and BEM for a linear 2D Laplace transmission problem.
We rigorously prove that the condition number of the preconditioned system
stays uniformly bounded, independently of the refinement level and the local
mesh-size of the underlying adaptively refined triangulations. Although the
focus is on the non-symmetric Johnson-N\'ed\'elec one-equation coupling, the
principle ideas also apply to other formulations like the symmetric FEM-BEM
coupling. Numerical experiments underline our theoretical findings.


title: Review of the Theory of PWNe

abstract:
  Pulsar Wind Nebulae (PWNe) are ideal astrophysical laboratories where high
energy relativistic phenomena can be investigated. They are close, well
resolved in our observations, and the knowledg derived in their study has a
strong impact in many other fields, from AGNs to GRBs. Yet there are still
unresolved issues, that prevent us from a full clear understanding of these
objects. The lucky combination of high resolution X-ray imaging and numerical
codes to handle the outflow and dynamical properties of relativistic MHD, has
opened a new avenue of investigation that has lead to interesting progressed in
the last years. Despite all of these, we do not understand yet how particles
are accelerated, and the functioning of the pulsar wind and pulsar
magnetosphere, that power PWNe. I will review what is now commonly known as the
MHD paradigm, and in particular I will focus on various approaches that have
been and are currently used to model these systems. For each I will highlight
its advantages and limitations, and degree of applicability.


title:
The $\alpha^2(Z\alpha)^4m$ contributions to the Lamb shift and the fine
  structure in light muonic atoms

abstract:
  Corrections to energy levels in light muonic atoms are investigated in order
$\alpha^2(Z\alpha)^4m$. We pay attention to corrections which are specific for
muonic atoms and include the electron vacuum polarization loop. In particular,
we calculate relativistic and relativistic-recoil two-loop electron vacuum
polarization contributions. The results are obtained for the levels with
$n=1,2$ and in particular for the Lamb shift ($2p_{1/2}-2s_{1/2}$) and
fine-structure intervals ($2p_{3/2}-2p_{1/2}$) in muonic hydrogen, deuterium,
and muonic helium ions.


title:
Study of Baryonic R-Parity Violating MSSM Using Jet Substructure
  Technique at the 14 TeV LHC

abstract:
  We study the discovery reach of the gluino ($\widetilde{g}$) and the lightest
stop squark ($\widetilde{t}_1$) with baryonic R-parity violation (UDD type) in
the context of Minimal Supersymmetric Standard Model (MSSM) at the 14 TeV run
of the LHC. We consider the gluino pair production process followed by its
decay to a top quark and a real or virtual stop squark. The top quark produced
from the decay of the gluino can have sufficient transverse momentum to appear
as a single fat jet. We apply the jet substructure technique to tag such a
hadronically decaying boosted top quark and find that gluino mass up to 1.65
TeV can be discovered whereas exclusion limit extends up to 1.9 TeV at the 14
TeV LHC with 300 $\rm fb^{-1}$ luminosity. We also briefly discuss the
discovery prospect of the boosted stop squark which may be identified as a
narrow resonance in the jet mass distribution.


title:
On the convergence of densities of finite voter models to the
  Wright-Fisher diffusion

abstract:
  We study voter models defined on large sets. Through a perspective
emphasizing the martingale property of voter density processes, we prove that
in general, their convergence to the Wright-Fisher diffusion only involves
certain averages of the voter models over a small number of spatial locations.
This enables us to identify suitable mixing conditions on the underlying voting
kernels, one of which may just depend on their eigenvalues in some contexts, to
obtain the convergence of density processes. Our examples show that these
conditions are satisfied by a large class of voter models on growing finite
graphs.


title: Trajectory control of a bipedal walking robot with inertial disc

abstract:
  In this paper we exploit some interesting properties of a class of bipedal
robots which have an inertial disc. One of this properties is the ability to
control every position and speed except for the disc position. The proposed
control is designed in two hierarchic levels. The first will drive the robot
geometry, while the second will control the speed and also the angular
momentum. The exponential stability of this approach is proved around some
neighborhood of the nominal trajectory defining the geometry of the step. This
control will not spend energy to adjust the disc position and neither to
synchronize the trajectory with the time. The proposed control only takes
action to correct the essential aspects of the walking gait. Computational
simulations are presented for different conditions, serving as a empirical test
for the neighborhood of attraction.


title:
An improved beam waist formula for ultrashort, tightly-focused linearly,
  radially, and azimuthally polarized laser pulses in free space

abstract:
  We derive an asymptotically accurate formula for the beam waist of
ultrashort, tightly-focused fundamental linearly-polarized, radially-polarized,
and azimuthally-polarized modes in free space. We compute the exact beam waist
via numerical cubature to ascertain the accuracy with which our formula
approximates the exact beam waist over a broad range of parameters of practical
interest. Based on this, we describe a method of choosing parameters in the
model given the beam waist and pulse duration of a laser pulse.


title:
Relativistic recoil effects in a muonic atom within a Grotch-type
  approach: General approach

abstract:
  Recently we calculated relativistic recoil corrections to the energy levels
of the low lying states in muonic hydrogen induced by electron vacuum
polarization effects. The results were obtained by Breit-type and Grotch-type
calculations. The former were described in our previous papers in detail, and
here we present the latter.
  The Grotch equation was originally developed for pure Coulomb systems and
allowed to express the relativistic recoil correction in order
$(Z\alpha)^4m^2/M$ in terms of the relativistic non-recoil contribution
$(Z\alpha)^4m$. Certain attempts to adjust the method to electronic vacuum
polarization took place in the past, however, the consideration was incomplete
and the results were incorrect.
  Here we present a Groth-type approach to the problem and in a series of
papers consider relativistic recoil effects in order $\alpha(Z\alpha)^4m^2/M$
and $\alpha^2(Z\alpha)^4m^2/M$. That is the first paper of the series and it
presents a general approach, while two other papers present results of
calculations of the $\alpha(Z\alpha)^4m^2/M$ and $\alpha^2(Z\alpha)^4m^2/M$
contributions in detail. In contrast to our previous calculation, we address
now a variety of states in muonic atoms with a certain range of the nuclear
charge $Z$.


title:
Relativistic recoil effects for energy levels in a muonic atom within a
  Grotch-type approach: An application to the one-loop electronic vacuum
  polarization

abstract:
  We continue our account of relativistic recoil effects in muonic atoms and
present explicitly analytic results at first order in
electron-vacuum-polarization effects. The results are obtained within a
Grotch-type approach based on an effective Dirac equation. Some expressions are
cumbersome and we investigate their asymptotic behavior. Previously
relativistic two-body effects due to the one-loop electron vacuum polarization
were studied by several groups. Our results found here are consistent with the
previous result derived within a Breit-type approach (including ours) and
disagree with a recent attempt to apply a Grotch-type approach.


title: Two-Color-Laser-Driven Direct Electron Acceleration in Infinite Vacuum

abstract:
  We propose a direct electron acceleration scheme that uses a two-color pulsed
radially-polarized laser beam. The two-color scheme achieves electron
acceleration exceeding 90% of the theoretical energy gain limit, over twice of
what is possible with a one-color pulsed beam of equal total energy and pulse
duration. The scheme succeeds by exploiting the Gouy phase shift to cause an
acceleration-favoring interference of fields only as the electron enters its
effectively final accelerating cycle. Optimization conditions and power scaling
characteristics are discussed.


title:
Direct acceleration of an electron in infinite vacuum by a pulsed
  radially-polarized laser beam

abstract:
  We study the direct acceleration of a free electron in infinite vacuum along
the axis of a pulsed radially-polarized laser beam. We find that net energy
transfer from laser pulse to electron is maximized with the tightest focusing.
We show that the net energy gain of an electron initially moving at a
relativistic velocity may exceed more than half the theoretical limit of energy
transfer, which is not possible with an initially stationary electron in the
parameter space studied. We determine and analyze the power scaling of maximum
energy gain, extending our study to include a relatively unexplored regime of
low powers and revealing that substantial acceleration is already possible
without the use of petawatt peak-power laser technology.


title:
A Threshold for Laser-Driven Linear Particle Acceleration in Unbounded
  Vacuum

abstract:
  We hypothesize that a charged particle in unbounded vacuum can be
substantially accelerated by a force linear in the electric field of a
propagating electromagnetic wave only if the accelerating field is capable of
bringing the particle to a relativistic energy in its initial rest frame during
the interaction. We consequently derive a general formula for the acceleration
threshold of such schemes and support our conclusion with the results of
numerical simulations over a broad range of parameters for different kinds of
pulsed laser beams.


title:
Pekeris-type approximation for the $l$-wave in a P\"oschl-Teller
  potential

abstract:
  An approximation for the centrifugal term which transforms the radial
equation for a particle in a P\"oschl-Teller potential into an exactly solvable
approximate equation is proposed. In contrast to the approximations known in
the literature, the new one can be used with the most general form of the
central P\"oschl-Teller potential. An approximate expression for the
bound-state spectrum is obtained.


title:
Evolving functional network properties and synchronizability during
  human epileptic seizures

abstract:
  We assess electrical brain dynamics before, during, and after one-hundred
human epileptic seizures with different anatomical onset locations by
statistical and spectral properties of functionally defined networks. We
observe a concave-like temporal evolution of characteristic path length and
cluster coefficient indicative of a movement from a more random toward a more
regular and then back toward a more random functional topology. Surprisingly,
synchronizability was significantly decreased during the seizure state but
increased already prior to seizure end. Our findings underline the high
relevance of studying complex systems from the view point of complex networks,
which may help to gain deeper insights into the complicated dynamics underlying
epileptic seizures.


title: Unscented Orientation Estimation Based on the Bingham Distribution

abstract:
  Orientation estimation for 3D objects is a common problem that is usually
tackled with traditional nonlinear filtering techniques such as the extended
Kalman filter (EKF) or the unscented Kalman filter (UKF). Most of these
techniques assume Gaussian distributions to account for system noise and
uncertain measurements. This distributional assumption does not consider the
periodic nature of pose and orientation uncertainty. We propose a filter that
considers the periodicity of the orientation estimation problem in its
distributional assumption. This is achieved by making use of the Bingham
distribution, which is defined on the hypersphere and thus inherently more
suitable to periodic problems. Furthermore, handling of non-trivial system
functions is done using deterministic sampling in an efficient way. A
deterministic sampling scheme reminiscent of the UKF is proposed for the
nonlinear manifold of orientations. It is the first deterministic sampling
scheme that truly reflects the nonlinear manifold of the orientation.


title: The Arnold-Tongue of Coupled Acoustic Oscillators

abstract:
  Wind-driven sound generation is a source of anger and pleasure, depending on
the situation: airframe and car noise, or combustion noise are some of the most
disturbing environmental pollutions, whereas musical instruments are sources of
joy. We present an experiment on two coupled sound sources -organ pipes-
together with a theoretical model which takes into account the underlying
physics. Our focus is the Arnold tongue which quantitatively captures the
interaction of the sound sources, we obtain very good agreement of model and
experiment, the results are supported by very detailed CFD computations.


title: The non-existence of the self-accelerating dipole, and related questions

abstract:
  We calculate the self-force of a constantly accelerating electric dipole,
showing, in particular, that classical electromagnetism does not predict that
an electric dipole could self-accelerate, nor could it levitate in a
gravitational field. We also resolve a paradox concerning the inertial mass of
a longitudinally accelerating dipole, showing that the combined system of
dipole plus field can be assigned a well-defined energy-momentum four-vector,
so that the Principle of Relativity is satisfied. We then present some general
features of electromagnetic phenomena in a gravitational field described by the
Rindler metric, showing in particular that an observer fixed in a gravitational
field described by the Rindler metric will find any charged object supported in
the gravitational field to possess an electromagnetic self-force equal to that
observed by an inertial observer relative to which the body undergoes rigid
hyperbolic motion. It follows that the Principle of Equivalence is satisfied by
these systems.


title: Brzozowski type determinization for fuzzy automata

abstract:
  In this paper we adapt the well-known Brzozowski determinization method to
fuzzy automata. This method gives better results than all previously known
methods for determinization of fuzzy automata developed by B\v{e}lohl\'avek
[Inform Sciences 143 (2002) 205--209], Li and Pedrycz [Fuzzy Set Syst 156
(2005) 68--92], Ignjatovi\'c et al. [Inform Sciences 178 (2008) 164--180], and
Jan\v{c}i\'c et al. [Inform Sciences 181 (2011) 1358--1368]. Namely, as in the
case of ordinary nondeterministic automata, Brzozowski type determinization of
a fuzzy automaton results in a minimal crisp-deterministic fuzzy automaton
equivalent to the starting fuzzy automaton, and we show that there are cases
when all previous methods result in infinite automata, while Brzozowski type
determinization results in a finite one. The paper deals with fuzzy automata
over complete residuated lattices, but identical results can also be obtained
in a more general context, for fuzzy automata over lattice-ordered monoids, and
even for weighted automata over commutative semirings.


title: Large-Spin Expansions of GKP Strings

abstract:
  We demonstrate that the large-spin expansion of the energy of
Gubser-Klebanov-Polyakov (GKP) strings that rotate in RxS2 and AdS3 can be
expressed in terms of Lambert's W-function. We compute the leading, subleading
and next-to-subleading series of exponential corrections to the infinite-volume
dispersion relation of GKP strings that rotate in RxS2. These strings are dual
to certain long operators of N=4 SYM theory and provide their scaling
dimensions at strong coupling. We also show that the strings obey a short-long
(strings) duality. For the folded GKP strings that spin inside AdS3 and are
dual to twist-2 operators, we confirm the known formulas for the leading and
next-to-leading coefficients of their anomalous dimensions and derive the
corresponding expressions for the next-to-next-to-leading coefficients.


title:
Self-energy and vertex functions from hybridization expansion
  continuous-time quantum Monte Carlo for impurity models with retarded
  interaction

abstract:
  Optimized measurements for the susceptibility, self-energy, as well as
three-leg and four-leg vertex functions are introduced for the continuous-time
hybridization expansion quantum Monte Carlo solver for the impurity model in
presence of a retarded interaction. The self-energy and vertex functions are
computed from impurity averages which involve time integrals over the retarded
interaction. They can be evaluated efficiently within the segment
representation. These quantities are computed within dynamical mean-field
theory in presence of plasmonic screening. In the antiadiabatic regime, the
self-energy is strongly renormalized but retains features of the low energy
scale set by the screened interaction. An explicit expression for its
high-frequency behavior is provided. Across the screening-driven and
interaction-driven metal-insulator transitions, the vertex functions are found
to exhibit similar structural changes, which are hence identified as generic
features of the Mott transition.


title:
Loosening the notions of compliance and sub-behaviour in client/server
  systems

abstract:
  In the context of "session behaviors" for client/server systems, we propose a
weakening of the compliance and sub-behaviour relations where the bias toward
the client (whose "requests" must be satisfied) is pushed further with respect
to the usual definitions, by admitting that "not needed" output actions from
the server side can be "skipped" by the client. Both compliance and
sub-behaviour relations resulting from this weakening remain decidable, though
the proof of the duals-as-minima property for servers, on which the
decidability of the sub-behaviour relation relies, requires a tighter analysis
of client/server interactions.


title: Algebraic Morse theory and homological perturbation theory

abstract:
  We show that the main result of algebraic Morse theory can be obtained as a
consequence of the perturbation lemma of Brown and Gugenheim.


title:
A high-statistics study of the nucleon EM form factors, axial charge and
  quark momentum fraction

abstract:
  We present updated results for the nucleon axial charge and electromagnetic
(EM) form factors, which include a significant increase in statistics for all
ensembles (up to 4000 measurements), as well as the addition of ensembles with
pion masses down to $m_\pi\sim195$ MeV. We also present results for the average
quark momentum fraction. The new data allows us to perform a thorough study of
the systematic effects encountered in the lattice extraction. We concentrate on
systematic effects due to excited-state contaminations for each of the
quantities, which we check using several different time separations between the
operators at the source and sink through a comparison of plateau fits and the
summed operator insertion method (which provides a mechanism to suppress the
excited-state contamination). We confirm our earlier finding that a reliable
extraction of the axial charge must be based on a method which eliminates
excited-state contaminations. Similar conclusions apply to our EM form factor
calculations . The measurements are calculated using the CLS ensembles with
non-perturbatively O(a) improved Wilson fermions in $N_f=2$ QCD.


title: Elastodynamics and resonances in elliptical geometry

abstract:
  The resonant modes of two-dimensional elastic elliptical objects are studied
from a modal formalism by emphasizing the role of the symmetries of the
objects. More precisely, as the symmetry is broken in the transition from the
circular disc to the elliptical one, the splitting up of resonances and level
crossings are observed. From the mathematical point of view, this observation
can be explained by the broken invariance of the continuous symmetry group O(2)
associated with the circular disc. The elliptical disc is however invariant
under the finite group C2v and the resonances are classified and associated
with a given irreducible representation of this group. The main difficulty
arises in the application of the group theory in elastodynamics where the
vectorial formalism is used to express the physical quantities (elastic
displacement and stress) involved in the boundary conditions. However, this
method significantly simplifies the numerical treatment of the problem which is
uncoupled over the four irreducible representations of C2v. This provides a
full classification of the resonances. They are tagged and tracked as the
eccentricity of the elliptical disc increases. Then, the splitting up of
resonances, which occurs in the transition from the circular disc to the
elliptic one, is emphasized. The computation of displacement normal modes also
highlights the mode splittings. A physical interpretation of resonances in
terms of geometrical paths is provided.


title:
Analysis of Load Balancing in Large Heterogeneous Processor Sharing
  Systems

abstract:
  We analyze randomized dynamic load balancing schemes for multi-server
processor sharing systems when the number of servers in the system is large and
the servers have heterogeneous service rates. In particular, we focus on the
classical power-of-two load balancing scheme and a variant of it in which a
newly arrived job is assigned to the server having the least instantaneous
Lagrange shadow cost among two randomly chosen servers. The instantaneous
Lagrange shadow cost at a server is given by the ratio of the number of
unfinished jobs at the server to the capacity of the server. Two different
approaches of analysis are presented for each scheme. For exponential job
length distribution, the analysis is done using the mean field approach and for
more general job length distributions the analysis is carried out assuming an
asymptotic independence property. Analytical expressions to compute mean
sojourn time of jobs are found for both schemes. Asymptotic insensitivity of
the schemes to the type of job length distribution is established. Numerical
results are presented to validate the theoretical results and to show that,
unlike the homogeneous scenario, the power-of-two type schemes considered in
this paper may not always result in better behaviour in terms of the mean
sojourn time of jobs.


title:
Thermally excited multi-band conduction in LaAlO3/SrTiO3
  heterostructures exhibiting magnetic scattering

abstract:
  Magnetotransport measurements of charge carriers at the interface of a
LaAlO3/SrTiO3 heterostructure with 26 unit cells of LaAlO3 show Hall resistance
and magnetoresistance which at low and high temperatures is described by a
single channel of electron-like charge carriers. At intermediate temperatures,
we observe non-linear Hall resistance and positive magnetoresistance,
establishing the presence of at least two electron-like channels with
significantly different mobilities and carrier concentrations. These channels
are separated by 6 meV in energy and their temperature dependent occupation and
mobilities are responsible for the observed transport properties of the
interface. We observe that one of the channels has a mobility that decreases
with decreasing temperature, consistent with magnetic scattering in this
channel.


title: Using Ring Laser Systems to Measure Gravitomagnetic Effects on Earth

abstract:
  Gravitomagnetic effects originates from the rotation of the source of the
gravitational field and from the rotational features of the observers' frame.
In recent years, gravitomagnetism has been tested by means of its impact on the
precession of LAGEOS orbits and on the precession of spherical gyroscopes in
the GP-B experiment. What we suggest here is that light can be used as a probe
to test gravitomagnetic effects in an terrestrial laboratory: the proposed
detector consists of large ring-lasers arranged along three orthogonal axes.


title: Entangling power of two-qubit gates on mixed states

abstract:
  The ability to reach a maximally entangled state from a separable one through
the use of a two-qubit unitary operator is analyzed for mixed states. This
extension from the known case of pure states shows that there are at least two
families of gates which are able to give maximum entangling power for all
values of purity. It is notable that one of this gates coincides with a maximum
discording one. We give analytical proof that such gate is indeed perfect
entangler at all purities and give numerical evidence for the existence of the
second one. Further, we find that there are other gates, many in fact, which
are perfect entanglers for a restricted range of purities. This highlights the
fact that many perfect entangler gates could in principle be found if a
thorough analysis of the full parameter space is performed.


title: Deciding $k$CFA is complete for EXPTIME

abstract:
  We give an exact characterization of the computational complexity of the
$k$CFA hierarchy. For any $k > 0$, we prove that the control flow decision
problem is complete for deterministic exponential time. This theorem validates
empirical observations that such control flow analysis is intractable. It also
provides more general insight into the complexity of abstract interpretation.


title: Event-by-event weighting at next-to-leading order

abstract:
  We present a general method of associating next-to-leading order weights to
leading order phase space configurations at hadron colliders. The method relies
on a re-organization of phase space for the real radiation contributions,
defining a one-to-many map such that each point in the real phase space is
associated with a distinct Born topology. As a result virtual and real
singularities cancel at each Born phase space point. The new phase space maps
can be used in a traditional approach for NLO calculations. However,
interesting applications arise when one instead integrates out the real
radiation up to a specified scale. This allows one to define NLO weights for
individual phase space points that are present at LO. This method allows for
the extension of matrix element methods to next-to-leading order, even in the
presence of jets. We discuss some recent applications of the matrix element
method to Higgs physics at the LHC.


title:
The effectiveness of thin films in lieu of hyperbolic metamaterials in
  the near field

abstract:
  We show that the near-field functionality of hyperbolic metamaterials (HMM),
typically proposed for increasing the photonic local density of states (LDOS),
can be achieved with thin metal films. Although HMMs have an infinite density
of internally-propagating plane-wave states, the external coupling to nearby
emitters is severely restricted. We show analytically that properly designed
thin films, of thicknesses comparable to the metal size of a hyperbolic
metamaterial, yield a LDOS as high as (if not higher than) that of HMMs. We
illustrate these ideas by performing exact numerical computations of the LDOS
of multilayer HMMs, along with their application to the problem of maximizing
near-field heat transfer, to show that thin films are suitable replacements in
both cases.


title: 1/2, 1, and 3/2--Law Non-Radiative Accretion Flows

abstract:
  Assuming self-similarity of the first kind, we get three possible values
p=1/2, 1, 3/2 for the exponent describing the density profile, rho r^{-p}, of a
non-radiative (and hence quasi-spherical) accretion flow. The high and low p
cases are known as Bondi and Convection-Dominated accretion flows. The 1-law
flow we tentatively identify with the so-called Magnetically-Frustrated
accretion flow. If our interpretation is correct, the accretion flow must be,
roughly speaking, a collection of Prandtl's turbulent jets. The 1-law flow,
being a first-kind self-similar solution, may actually occur in nature (in
collisionless plasma).


title: Dynamics of a strongly coupled polaron

abstract:
  We study the dynamics of large polarons described by the Froehlich
Hamiltonian in the limit of strong coupling. The initial conditions are
(perturbations of) product states of an electron wave function and a phonon
coherent state, as suggested by Pekar. We show that, to leading order on the
natural time scale of the problem, the phonon field is stationary and the
electron moves according to an effective linear Schroedinger equation.


title: Probing color coherence effects in pp collisions at sqrt(s) = 7 TeV

abstract:
  A study of color coherence effects in pp collisions at a center-of-mass
energy of 7 TeV is presented. The data used in the analysis were collected in
2010 with the CMS detector at the LHC and correspond to an integrated
luminosity of 36 inverse picobarns. Events are selected that contain at least
three jets and where the two jets with the largest transverse momentum exhibit
a back-to-back topology. The measured angular correlation between the second-
and third-leading jet is shown to be sensitive to color coherence effects, and
is compared to the predictions of Monte Carlo models with various
implementations of color coherence. None of the models describe the data
satisfactorily.


title:
Sinkless: A Preliminary Study of Stress Propagation in Group Project
  Social Networks using a Variant of the Abelian Sandpile Model

abstract:
  We perform social network analysis on 53 students split over three semesters
and 13 groups, using conventional measures like eigenvector centrality,
betweeness centrality, and degree centrality, as well as defining a variant of
the Abelian Sandpile Model (ASM) with the intention of modeling stress
propagation in the college classroom. We correlate the results of these
analyses with group project grades received; due to a small or poorly collected
dataset, we are unable to conclude that any of these network measures relates
to those grades. However, we are successful in using this dataset to define a
discrete, recursive, and more generalized variant of the ASM. Abelian Sandpile
Model, College Grades, Self-organized Criticality, Sinkless Sandpile Model,
Social Network Analysis, Stress Propagation


title: Magnetoresistance of composites based on graphitic disks and cones

abstract:
  We have studied the magnetotransport of conical and disk-shaped nanocarbon
particles in magnetic fields $\left|B\right|\leq9\:\mathrm{T}$ at temperatures
$2\leq T\leq300\:\mathrm{K}$ to characterize electron scattering in a three
dimensional disordered material of multilayered quasi 2D and 3D carbon
nanoparticles. The microstructure of the particles was modified by
graphitization at temperatures $1600^{\circ}\mathrm{C}$ and
$2700^{\circ}\mathrm{C}$. We find clear correlations between the microstructure
as seen in transmission electron microscopy and the magnetotransport properties
of the particles. The magnetoresistance measurements showed a metallic nature
of samples and positive magnetoconductance which is a signature of weak
localization in disordered systems. We find that the magnetoconductance at low
temperatures resembles quantum transport in single-layer graphene despite the
fact that the samples are macroscopic and three dimensional, consisting of
stacked and layered particles, which are randomly oriented in the bulk sample.
This graphene-like behaviour is attributed to the very weak interlayer coupling
between the graphene layers.


title: Sparse halves in dense triangle-free graphs

abstract:
  Erd\H{o}s conjectured that every triangle-free graph $G$ on $n$ vertices
contains a set of $\lfloor n/2 \rfloor$ vertices that spans at most $n^2 /50$
edges. Krivelevich proved the conjecture for graphs with minimum degree at
least $\frac{2}{5}n$. Keevash and Sudakov improved this result to graphs with
average degree at least $\frac{2}{5}n$. We strengthen these results by showing
that the conjecture holds for graphs with minimum degree at least
$\frac{5}{14}n$ and for graphs with average degree at least $(\frac{2}{5} -
\varepsilon)n$ for some absolute $\varepsilon >0$. Moreover, we show that the
conjecture is true for graphs which are close to the Petersen graph in edit
distance.


title:
Asymptotics of the minimal clade size and related functionals of certain
  beta-coalescents

abstract:
  This article shows the asymptotics of distributions of various functionals of
the Beta$(2-\alpha,\alpha)$ $n$-coalescent process with $1<\alpha<2$ when $n$
goes to infinity. This process is a Markov process taking {values} in the set
of partitions of $\{1, \dots, n\}$, evolving from the intial value
$\{1\},\cdots, \{n\}$ by merging (coalescing) blocks together into one and
finally reaching the absorbing state $\{1, \dots, n\}$. The minimal clade of
$1$ is the block which contains $1$ at the time of coalescence of the singleton
$\{1\}$. The limit size of the minimal clade of $1$ is provided. To this, we
express it as a function of the coalescence time of $\{1\}$ and sizes of blocks
at that time. Another quantity concerning the size of the largest block (at
deterministic small time and at the coalescence time of $\{1\}$) is also
studied.


title:
Circular geodesics of naked singularities in the Kehagias-Sfetsos metric
  of Ho\v{r}ava's gravity

abstract:
  We discuss photon and test-particle orbits in the Kehagias-Sfetsos (KS)
metric. For any value of the Ho\v{r}ava parameter $\omega$, there are values of
the gravitational mass $M$ for which the metric describes a naked singularity,
and this is always accompanied by a vacuum "antigravity sphere" on whose
surface a test particle can remain at rest (in a zero angular momentum
geodesic), and inside which no circular geodesics exist. The observational
appearance of an accreting KS naked singularity in a binary system would be
that of a quasi-static spherical fluid shell surrounded by an accretion disk,
whose properties depend on the value of $M$, but are always very different from
accretion disks familiar from the Kerr-metric solutions. The properties of the
corresponding circular orbits are qualitatively similar to those of the
Reissner-Nordstr\"om naked singularities. When event horizons are present, the
orbits outside the Kehagias-Sfetsos black hole are qualitatively similar to
those of the Schwarzschild metric.


title: Ginzburg-Landau Approach to Holographic Superconductivity

abstract:
  We construct a family of minimal phenomenological models for holographic
superconductors in d=4+1 AdS spacetime and study the effect of scalar and gauge
field fluctuations. By making a Ginzburg-Landau interpretation of the dual
field theory, we determine through holographic techniques a phenomenological
Ginzburg-Landau Lagrangian and the temperature dependence of physical
quantities in the superconducting phase. We obtain insight on the behaviour of
the Ginzburg-Landau parameter and whether the systems behaves as a Type I or
Type II superconductor. Finally, we apply a constant external magnetic field in
a perturbative approach following previous work by D'Hoker and Kraus, and
obtain droplet solutions which signal the appearance of the Meissner effect.


title:
Relativistic recoil effects to energy levels in a muonic atom: a
  Grotch-type calculation of the second-order vacuum-polarization contributions

abstract:
  Adjusting a previously developed Grotch-type approach to a perturbative
calculation of the electronic vacuum-polarization effects in muonic atoms, we
find here the two-loop vacuum polarization relativistic recoil correction of
order $\alpha^2(Z\alpha)^4m^2/M$ in light muonic atoms. The result is in
perfect agreement with the one previously obtained within the Breit-type
approach. We also discuss here simple approximations of the irreducible part of
the two-loop vacuum-polarization dispersion density, which was applied to test
our calculations and can be useful for other evaluations with an uncertainty
better than 1%.


title: Probabilistic picture for medium-induced jet evolution

abstract:
  A high energy jet that propagates in a dense medium generates a cascade of
partons that can be described as a classical branching process. A simple
generating functional for the probabilities to observe a given number of gluons
at a given time is derived. This is used to obtain an evolution equation for
the inclusive one-gluon distribution, that takes into account the dependence
upon the energy and the transverse momentum of the observed gluon. A study of
the explicit transverse momentum dependence of the splitting kernel leads us to
identify large corrections to the jet quenching parameter.


title: Photoluminescence of freestanding single- and few-layer MoS2

abstract:
  We present a photoluminescence study of freestanding and Si/SiO2 supported
single- and few-layer MoS2. The single-layer exciton peak (A) is only observed
in freestanding MoS2. The photoluminescence of supported single-layer MoS2 is
instead originating from the A- (trion) peak as the MoS2 is n-type doped from
the substrate. In bilayer MoS2, the van der Waals interaction with the
substrate is decreasing the indirect band gap energy by up to ~ 80 meV.
Furthermore, the photoluminescence spectra of suspended MoS2 can be influenced
by interference effects.


title: Flow analysis, linearity, and PTIME

abstract:
  Flow analysis is a ubiquitous and much-studied component of compiler
technology---and its variations abound. Amongst the most well known is Shivers'
0CFA; however, the best known algorithm for 0CFA requires time cubic in the
size of the analyzed program and is unlikely to be improved. Consequently,
several analyses have been designed to approximate 0CFA by trading precision
for faster computation. Henglein's simple closure analysis, for example,
forfeits the notion of directionality in flows and enjoys an "almost linear"
time algorithm. But in making trade-offs between precision and complexity, what
has been given up and what has been gained? Where do these analyses differ and
where do they coincide?
  We identify a core language---the linear $\lambda$-calculus---where 0CFA,
simple closure analysis, and many other known approximations or restrictions to
0CFA are rendered identical. Moreover, for this core language, analysis
corresponds with (instrumented) evaluation. Because analysis faithfully
captures evaluation, and because the linear $\lambda$-calculus is complete for
PTIME, we derive PTIME-completeness results for all of these analyses.


title:
An optimization problem for nonliear Steklov eigenvalues with a boundary
  potential

abstract:
  In this paper, we analyze an optimization problem for the first (nonlinear)
Steklov eigenvalue plus a boundary potential with respect to the potential
function which is assumed to be uniformly bounded and with fixed $L^1$-norm.


title:
Transition in coupled replicas may not imply a finite temperature ideal
  glass transition in glass forming systems

abstract:
  A key open question in the glass transition field is whether a finite
temperature thermodynamic transition to the glass state exists or not. Recent
simulations of coupled replicas in atomistic models have found signatures of a
static transition as a function of replica coupling. This can be viewed as
evidence of an associated thermodynamic glass transition in the uncoupled
system. We demonstrate here that a different interpretation is possible. We
consider the triangular plaquette model, an interacting spin system which
displays (East model-like) glassy dynamics in the absence of any static
transition. We show that when two replicas are coupled there is a curve of
equilibrium phase transitions, between phases of small and large overlap, in
the temperature-coupling plane (located on the self-dual line of an exact
temperature/coupling duality of the system) which ends at a critical point.
Crucially, in the limit of vanishing coupling the finite temperature transition
disappears, and the uncoupled system is in the disordered phase at all
temperatures. We discuss interpretation of atomistic simulations in light of
this result.


title: The Splice Bootstrap

abstract:
  This paper proposes a new bootstrap method to compute predictive intervals
for nonlinear autoregressive time series model forecast. This method we call
the splice boobstrap as it involves splicing the last p values of a given
series to a suitably simulated series. This ensures that each simulated series
will have the same set of p time series values in common, a necessary
requirement for computing conditional predictive intervals. Using simulation
studies we show the methods gives 90% intervals intervals that are similar to
those expected from theory for simple linear and SETAR model driven by normal
and non-normal noise. Furthermore, we apply the method to some economic data
and demonstrate the intervals compare favourably with cross-validation based
intervals.


title: Neural Network Application on Foliage Plant Identification

abstract:
  Several researches in leaf identification did not include color information
as features. The main reason is caused by a fact that they used green colored
leaves as samples. However, for foliage plants, plants with colorful leaves,
fancy patterns in their leaves, and interesting plants with unique shape, color
and also texture could not be neglected. For example, Epipremnum pinnatum
'Aureum' and Epipremnum pinnatum 'Marble Queen' have similar patterns, same
shape, but different colors. Combination of shape, color, texture features, and
other attribute contained on the leaf is very useful in leaf identification. In
this research, Polar Fourier Transform and three kinds of geometric features
were used to represent shape features, color moments that consist of mean,
standard deviation, skewness were used to represent color features, texture
features are extracted from GLCMs, and vein features were added to improve
performance of the identification system. The identification system uses
Probabilistic Neural Network (PNN) as a classifier. The result shows that the
system gives average accuracy of 93.0833% for 60 kinds of foliage plants.


title: Dictionary-Learning-Based Reconstruction Method for Electron Tomography

abstract:
  Electron tomography usually suffers from so called missing wedge artifacts
caused by limited tilt angle range. An equally sloped tomography (EST)
acquisition scheme (which should be called the linogram sampling scheme) was
recently applied to achieve 2.4-angstrom resolution. On the other hand, a
compressive sensing-inspired reconstruction algorithm, known as adaptive
dictionary based statistical iterative reconstruction (ADSIR), has been
reported for x-ray computed tomography. In this paper, we evaluate the EST,
ADSIR and an ordered-subset simultaneous algebraic reconstruction technique
(OS-SART), and compare the ES and equally angled (EA) data acquisition modes.
Our results show that OS-SART is comparable to EST, and the ADSIR outperforms
EST and OS-SART. Furthermore, the equally sloped projection data acquisition
mode has no advantage over the conventional equally angled mode in the context.


title: Unveil Compressed Sensing

abstract:
  We discuss the applicability of compressed sensing theory. We take a genuine
look at both experimental results and theoretical works. We answer the
following questions: 1) What can compressed sensing really do? 2) More
importantly, why?


title: Maximal Non-Exchangeability in Dimension d

abstract:
  We give the maximal distance between a copula and itself when the argument is
permuted for arbitrary dimension, generalizing a result for dimension two by
Nelsen (2007), Klement and Mesiar (2006). Furthermore, we establish a subset of
$[0,1]^d$ in which this bound might be attained. For each point in this subset
we present a copula and a permutation, for which the distance in this point is
maximal. In the process, we see that this subset depends on the dimension being
even or odd.


title: Slices of hermitian K-theory and Milnor's conjecture on quadratic forms

abstract:
  We advance the understanding of K-theory of quadratic forms by computing the
slices of the motivic spectra representing hermitian K-groups and Witt-groups.
By an explicit computation of the slice spectral sequence for higher
Witt-theory, we prove Milnor's conjecture relating Galois cohomology to
quadratic forms via the filtration of the Witt ring by its fundamental ideal.
In a related computation we express hermitian K-groups in terms of motivic
cohomology.


title:
Traffic and Statistical Multiplexing Characterization of 3D Video
  Representation Formats (Extended Version)

abstract:
  The network transport of 3D video, which contains two views of a video scene,
poses significant challenges due to the increased video data compared to
conventional single-view video. Addressing these challenges requires a thorough
understanding of the traffic and multiplexing characteristics of the different
representation formats of 3D video. We examine the average bitrate-distortion
(RD) and bitrate variability-distortion (VD) characteristics of three main
representation formats. Specifically, we compare multiview video (MV)
representation and encoding, frame sequential (FS) representation, and
side-by-side (SBS) representation, whereby conventional single-view encoding is
employed for the FS and SBS representations. Our results for long 3D videos in
full HD format indicate that the MV representation and encoding achieves the
highest RD efficiency, while exhibiting the highest bitrate variabilities. We
examine the impact of these bitrate variabilities on network transport through
extensive statistical multiplexing simulations. We find that when multiplexing
a small number of streams, the MV and FS representations require the same
bandwidth. However, when multiplexing a large number of streams or smoothing
traffic, the MV representation and encoding reduces the bandwidth requirement
relative to the FS representation.


title: Some lessons for us scientists (too) from the "Sokal affair"

abstract:
  In this little non-technical piece, I argue that some of the lessons that can
be learnt from the bold action carried out in 1996 by the physicist Alan Sokal
and typically known as the "Sokal affair" not only apply to some sector of the
humanities (which was the original target of the hoax), but also (with much
less intensity, but still) to the hardest sciences.


title: Automatic Ranking of MT Outputs using Approximations

abstract:
  Since long, research on machine translation has been ongoing. Still, we do
not get good translations from MT engines so developed. Manual ranking of these
outputs tends to be very time consuming and expensive. Identifying which one is
better or worse than the others is a very taxing task. In this paper, we show
an approach which can provide automatic ranks to MT outputs (translations)
taken from different MT Engines and which is based on N-gram approximations. We
provide a solution where no human intervention is required for ranking systems.
Further we also show the evaluations of our results which show equivalent
results as that of human ranking.


title:
Statistical Anisotropic Gaussian Simulations of the CMB Temperature
  Field

abstract:
  Although theoretically expected to be Statistically Isotropic (SI), the
observed Cosmic Microwave Background (CMB) temperature \& polarization field
would exhibit SI violation due to various inevitable effects like weak lensing,
Doppler boost and practical limitations of observations like non-circular beam,
masking etc. However, presence of any SI violation beyond these effects may
lead to a discovery of inherent cosmic SI violation in the CMB temperature \&
polarization field. Recently, Planck presented strong evidence of SI violation
as a dipolar power asymmetry of the CMB temperature field in two hemispheres.
Statistical studies of SI violation effect require non-SI (nSI) Gaussian
realizations of CMB temperature field. The nSI Gaussian temperature field leads
to non-zero off-diagonal terms in the Spherical Harmonics (SH) space covariance
matrix encoded in the coefficients of the Bipolar Spherical Harmonics (BipoSH)
representation. We discuss an effective numerical algorithm, Code for
Non-Isotropic Gaussian Sky (CoNIGS) to generate nSI realizations of Gaussian
CMB temperature field of Planck like resolution with specific cases of SI
violation. Realizations of nSI CMB temperature field are obtained for non-zero
quadrupolar $(L=2)$ BipoSH measurements by WMAP, dipolar asymmetry (resembles
$L=1$ BipoSH coefficients) with a \emph{scale dependent} modulation field as
measured by Planck and for Doppler boosted CMB temperature field which also
leads to $L=1$ BipoSH spectra. Our method, CoNIGS can incorporate any kind of
SI violation and can produce nSI realizations efficiently.


title: A Riemann--Hilbert approach to Jacobi operators and Gaussian quadrature

abstract:
  The computation of the entries of Jacobi operators associated with orthogonal
polynomials has important applications in numerical analysis. From truncating
the operator to form a Jacobi matrix, one can apply the Golub--Welsh algorithm
to compute the Gaussian quadrature weights and nodes. Furthermore, the entries
of the Jacobi operator are the coefficients in the three-term recurrence
relationship for the polynomials. This provides an efficient method for
evaluating the orthogonal polynomials. Here, we present an $\mathcal O(N)$
method to compute the first $N$ rows of Jacobi operators from the associated
weight. The method exploits the Riemann--Hilbert representation of the
polynomials by solving a deformed Riemann--Hilbert problem numerically. We
further adapt this computational approach to certain entire weights that are
beyond the reach of current asymptotic Riemann--Hilbert techniques.


title:
Exceptional sequences of maximal length on some surfaces isogenous to a
  higher product

abstract:
  Let $S=(C \times D)/G$ be a surface isogenous to a higher product of unmixed
type with $p_g=q=0$, $G=(\mathbb{Z}/2)^3$ or $(\mathbb{Z}/2)^4$. We construct
exceptional sequences of maximal length and quasiphantom categories on $S$.


title:
On an Atom-Interferometer Test of the Speed of Collapse of Wavefunctions
  in Relativistic Quantum Mechanics

abstract:
  I propose to resolve the controversy over the speed of collapse of
quantum-mechanical wavefunctions by means of an experimental test with a
modified symmetric Mach-Zehnder atom interferometer, with non-intersecting,
parallel, widely separated final beams. According to the conventional collapse
scenario, the coherent twin-peak atomic wavefunction in the beams of the
interferometer suffers an instantaneous collapse, at infinite speed, when the
atom is captured by one of the two detectors at the ends of the beams, but it
remains coherent until that instant. In contrast, according to the
Hellwig-Kraus relativistic collapse scenario, the wavefunction collapses at the
speed of light, backward in time along the past light cone of each detector.
This leads to a premature collapse, or pre-collapse, which for a beam-to-beam
separation of 3 m extends over a time span of 10 ns before arrival at the
detectors. Within this time span the paired wavepackets in the two beams will
be incoherent. The difference between the coherent wavepackets of the
conventional scenario and the incoherent wavepackets of the relativistic
scenario can be tested by probing the atomic beams with a transverse laser beam
crossing them near the detectors. If the paired atomic wavepackets in the two
beams are coherent, the light scattered by the two beams will also be coherent
and generate a standing light wave in the space between the beams, with
detectable interference fringes. If the paired wavepackets are incoherent, no
such interference fringes will be generated, and the distribution of the
scattered light will be that of two independent dipoles. The design parameters
for this test seem to lie within reach of the techniques of atom
interferometry.


title:
Dark Energy coupling with electromagnetism as seen from future
  low-medium redshift probes

abstract:
  Beyond the standard cosmological model the late-time accelerated expansion of
the universe can be reproduced by the introduction of an additional dynamical
scalar field. In this case, the field is expected to be naturally coupled to
the rest of the theory's fields, unless a (still unknown) symmetry suppresses
this coupling. Therefore, this would possibly lead to some observational
consequences, such as space-time variations of nature's fundamental constants.
In this paper we investigate the coupling between a dynamical Dark Energy model
and the electromagnetic field, and the corresponding evolution of the fine
structure constant ($\alpha$) with respect to the standard local value
$\alpha_0$. In particular, we derive joint constraints on two dynamical Dark
Energy model parametrizations (the Chevallier-Polarski-Linder and Early Dark
Energy model) and on the coupling with electromagnetism $\zeta$, forecasting
future low-medium redshift observations. We combine supernovae and weak lensing
measurements from the Euclid experiment with high-resolution spectroscopy
measurements of fundamental couplings and the redshift drift from the European
Extremely Large Telescope, highlighting the contribution of each probe.
Moreover, we also consider the case where the field driving the $\alpha$
evolution is not the one responsible for cosmic acceleration and investigate
how future observations can constrain this scenario.


title: Dissipation in a topological Josephson junction

abstract:
  Topological features of low dimensional superconductors have caused a lot of
excitement recently because of their broad range of applications in quantum
information and their potential to reveal novel phases of quantum matter. A
potential problem for practical applications is the presence of phase-slips
that break phase coherence. Dissipation in non-topological superconductors
suppresses phase-slips and can restore long-range order. Here we investigate
the role of dissipation in a topological Josephson junction. We show that the
combined effects of topology and dissipation keeps phase and anti-phase slips
strongly correlated so that the device is superconducting even under conditions
where a non-topological device would be resistive. The resistive transition
occurs at a critical value of the dissipation which is four times smaller than
that expected for a conventional Josephson junction. We propose that this
difference could be employed as a robust experimental signature of topological
superconductivity.


title: A traffic model based on fuzzy cellular automata

abstract:
  Cellular automata (CA) play an important role in the development of
computationally efficient microscopic traffic models and recently have gained
considerable importance as a mean of optimising traffic control strategies.
However, real-time application of the available CA models in traffic control
systems is a difficult task due to their discrete and stochastic nature. This
paper introduces a novel method for simulation of signalised traffic streams,
which combines CA and fuzzy numbers. The introduced traffic simulation
algorithm eliminates main drawbacks of the CA approach, i.e. necessity of
multiple Monte Carlo simulations and calibration issues. Computational cost of
traffic simulation for the proposed algorithm is considerably lower than the
cost of simulation based on stochastic CA. Thus, the simulation results can be
obtained in a much shorter time. Experiments confirmed that the simulation
results for the introduced algorithm are consistent with that observed for
stochastic CA. The proposed simulation algorithm is suitable for real-time
applications in traffic control systems.


title:
Measurement and modeling of the mechanical and electrochemical response
  of amorphous Si thin film electrodes during cyclic lithiation

abstract:
  A combination of experimental measurements and numerical simulations are used
to characterize the mechanical and electrochemical response of thin film
amorphous Si electrodes during cyclic lithiation. Parameters extracted from the
experiment include the variation of elastic modulus and the flow stress as
functions of Li concentration; the strain rate sensitivity; the diffusion
coefficient for Li transport in the electrode; the free energy of mixing as a
function of Li concentration in the electrode; the exchange current density for
the Lithium insertion reaction; as well as reaction rates and diffusion
coefficients characterizing the rate of formation of solid-electrolyte
interphase layer at the electrode surface. Model predictions are compared with
experimental measurements; and the implications for practical Si based
electrodes are discussed.


title: On linear series with negative Brill-Noether number

abstract:
  Brill-Noether theory studies the existence and deformations of curves in
projective spaces; its basic object of study is $\mathcal{W}^r_{d,g}$, the
moduli space of smooth genus $g$ curves with a choice of degree $d$ line bundle
having at least $(r+1)$ independent global sections. The Brill-Noether theorem
asserts that the map $\mathcal{W}^r_{d,g} \rightarrow \mathcal{M}_g$ is
surjective with general fiber dimension given by the number $\rho = g -
(r+1)(g-d+r)$, under the hypothesis that $0 \leq \rho \leq g$. One may
naturally conjecture that for $\rho < 0$, this map is generically finite onto a
subvariety of codimension $-\rho$ in $\mathcal{M}_g$. This conjecture fails in
general, but seemingly only when $-\rho$ is large compared to $g$. This paper
proves that this conjecture does hold for at least one irreducible component of
$\mathcal{W}^r_{d,g}$, under the hypothesis that $0 < -\rho \leq \frac{r}{r+2}
g - 3r+3$. We conjecture that this result should hold for all $0 < -\rho \leq g
+ C$ for some constant $C$, and we give a purely combinatorial conjecture that
would imply this stronger result.


title: Generic Newton polygons for curves of given p-rank

abstract:
  We survey results and open questions about the $p$-ranks and Newton polygons
of Jacobians of curves in positive characteristic $p$. We prove some geometric
results about the $p$-rank stratification of the moduli space of
(hyperelliptic) curves. For example, if $0 \leq f \leq g-1$, we prove that
every component of the $p$-rank $f+1$ stratum of ${\mathcal M}_g$ contains a
component of the $p$-rank $f$ stratum in its closure. We prove that the
$p$-rank $f$ stratum of $\overline{\mathcal M}_g$ is connected. For all primes
$p$ and all $g \geq 4$, we demonstrate the existence of a Jacobian of a smooth
curve, defined over $\overline{\mathbb F}_p$, whose Newton polygon has slopes
$\{0, \frac{1}{4}, \frac{3}{4}, 1\}$. We include partial results about the
generic Newton polygons of curves of given genus $g$ and $p$-rank $f$.


title: Liouville Brownian motion at criticality

abstract:
  In this paper, we construct the Brownian motion of Liouville Quantum Gravity
with central charge $c=1$ (more precisely we restrict to the corresponding free
field theory). Liouville quantum gravity with $c=1$ corresponds to
two-dimensional string theory and is the conjectural scaling limit of large
planar maps weighted with a $O(n=2)$ loop model or a $Q=4$-state Potts model
embedded in a two dimensional surface in a conformal manner.
  Following \cite{GRV1}, we start by constructing the critical LBM from one
fixed point $x\in\mathbb{R}^2$ (or $x\in\S^2$), which amounts to changing the
speed of a standard planar Brownian motion depending on the local behaviour of
the critical Liouville measure $M'(dx)=-X(x)e^{2X(x)}\,dx$ (where $X$ is a
Gaussian Free Field, say on $\mathbb{S}^2$). Extending this construction
simultaneously to all points in $\mathbb{R}^2$ requires a fine analysis of the
potential properties of the measure $M'$. This allows us to construct a strong
Markov process with continuous sample paths living on the support of $M'$,
namely a dense set of Hausdorff dimension $0$. We finally construct the
associated Liouville semigroup, resolvent, Green function, heat kernel and
Dirichlet form.
  In passing, we extend to quite a general setting the construction of the
critical Gaussian multiplicative chaos that was initiated in
\cite{Rnew7,Rnew12} and also establish new capacity estimates for the critical
Gaussian multiplicative chaos.


title: A 6D standing-wave Braneworld with normal matter as source

abstract:
  A six dimensional standing-wave braneworld model has been constructed. It
consists in an anisotropic 4-brane generated by standing gravitational waves
whose source is normal matter. In this model the compact (on-brane) dimension
is assumed to be sufficiently small in order to describe our universe (hybrid
compactification). The bulk geometry is non-static, unlike most of the
braneworld models in the literature. The principal feature of this model is the
fact that the source is not a phantom like scalar field, as the original
standing-wave model that was proposed in five dimensions and its six
dimensional extension recently proposed in the literature. Here it was obtained
a solution in the presence of normal matter what assures that the model is
stable. Also our model is the first standing wave brane model in the literature
which can be applied successfully to the hierarchy problem. Additionally, we
have shown that the zero-mode for the scalar and fermionic fields are localized
around the brane. Particularly for the scalar field we show that it is
localized on the brane, regardless the warp factor is decreasing or increasing.
This is in contrast to the case of the local string-like defect where the
scalar field is localized for a decreasing warp factor only.


title: Multi-Channel Data Acquisition System with Absolute Time Synchronization

abstract:
  A low-cost, stand-alone Global-Positioning-System-time-synchronized data
acquisition system is described. The constructed prototype allows recoding up
to four analog signals with a 16-bit resolution in variable ranges and a
maximum sampling rate of 1000 S/s. Additionally, two digital readouts of
external sensors can be acquired. A complete data set is stored on a Secure
Digital (SD) card or transmitted to a computer using Universal Serial Bus
(USB). The estimated time accuracy of the data acquisition is better than 0.2
{\mu}s. The device is envisioned for the use in a global distributed sensor
network (the Global Network of Optical Magnetometers for Exotic physics -
GNOME), whose aim is to search for new particles and interactions.


title: PDEs with Compressed Solutions

abstract:
  Sparsity plays a central role in recent developments in signal processing,
linear algebra, statistics, optimization, and other fields. In these
developments, sparsity is promoted through the addition of an $L^1$ norm (or
related quantity) as a constraint or penalty in a variational principle. We
apply this approach to partial differential equations that come from a
variational quantity, either by minimization (to obtain an elliptic PDE) or by
gradient flow (to obtain a parabolic PDE). Also, we show that some PDEs can be
rewritten in an $L^1$ form, such as the divisible sandpile problem and
signum-Gordon. Addition of an $L^1$ term in the variational principle leads to
a modified PDE where a subgradient term appears. It is known that modified PDEs
of this form will often have solutions with compact support, which corresponds
to the discrete solution being sparse. We show that this is advantageous
numerically through the use of efficient algorithms for solving $L^1$ based
problems.


title:
Entanglement Spectra of Interacting Fermions in Quantum Monte Carlo
  Simulations

abstract:
  In a recent article T. Grover [Phys. Rev. Lett. 111, 130402 (2013)]
introduced a simple method to compute Renyi entanglement entropies in the realm
of the auxiliary field quantum Monte Carlo algorithm. Here, we further develop
this approach and provide a stabilization scheme to compute higher order Renyi
entropies and an extension to access the entanglement spectrum. The method is
tested on systems of correlated topological insulators.


title: Long-term monitoring of Sgr A* at 7 mm with VERA and KaVA

abstract:
  We present the results of radio monitoring observations of Sgr A* at 7 mm
(i.e. 43 GHz) with VLBI Exploration of Radio Astrometry (VERA), which is a VLBI
array in Japan. VERA provides angular resolutions on millisecond scales,
resolving structure within ~100 Schwarzschild radii of Sgr A* similar to Very
Large Baseline Array (VLBA). We performed multi-epoch observations of Sgr A* in
2005 - 2008, and started monitoring it again with VERA from January 2013 for
tracing the current G2 encounter event. Our preliminary results in 2013 show
that Sgr A* on mas scales has been in ordinary state as of August 2013,
although some fraction of the G2 cloud already passed pericenter of Sgr A* in
April 2013. We will continue on monitoring Sgr A* with VERA and newly developed
KaVA (KVN and VERA Array).


title:
John Cage's Number Pieces as Stochastic Processes: a Large-Scale
  Analysis

abstract:
  The Number Pieces are a corpus of works by composer John Cage, which rely on
a particular time-structure used for determining the temporal location of
sounds, named the "time-bracket". The time-bracket system is an inherently
stochastic process, which complicates the analysis of the Number Pieces as it
leads to a large number of possibilities in terms of sonic content instead of
one particular fixed performance. The purpose of this paper is to propose a
statistical approach of the Number Pieces by assimilating them to stochastic
processes. Two Number Pieces, "Four" and "Five", are studied here in terms of
pitch-class set content: the stochastic processes at hand lead to a collection
of random variables indexed over time giving the distribution of the possible
pitch-class sets. This approach allows for a static and dynamic analysis of the
score encompassing all the possible outcomes during the performance of these
works.


title: Center of Mass and spin for isolated sources of gravitational radiation

abstract:
  We define the center of mass and spin of an isolated system in General
Relativity. The resulting relationships between these variables and the total
linear and angular momentum of the gravitational system are remarkably similar
to their Newtonian counterparts, though only variables at the null boundary of
an asymptotically flat spacetime are used for their definition. We also derive
equations of motion linking their time evolution to the emitted gravitational
radiation. The results are then compared to other approaches. In particular one
obtains unexpected similarities as well as some differences with results
obtained in the Post Newtonian literature . These equations of motion should be
useful when describing the radiation emitted by compact sources such as
coalescing binaries capable of producing gravitational kicks, supernovas, or
scattering of compact objects.


title:
Metal-Poor Stars Observed with the Magellan Telescope II. Discovery of
  Four Stars with [Fe/H] < -3.5

abstract:
  We report on the discovery of seven low-metallicity stars selected from the
Hamburg/ESO Survey, six of which are extremely metal-poor ([Fe/H]<-3.0), with
four having [Fe/H]<-3.5. Chemical abundances or upper limits are derived for
these stars based on high-resolution (R~35,000) Magellan/MIKE spectroscopy, and
are in general agreement with those of other very and extremely metal-poor
stars reported in the literature. Accurate metallicities and abundance patterns
for stars in this metallicity range are of particular importance for studies of
the shape of the metallicity distribution function of the Milky Way's halo
system, in particular for probing the nature of its low-metallicity tail. In
addition, taking into account suggested evolutionary mixing effects, we find
that six of the program stars (with [Fe/H]<-3.35) possess atmospheres that were
likely originally enriched in carbon, relative to iron, during their
main-sequence phases. These stars do not exhibit over-abundances of their
s-process elements, and hence may be additional examples of the so-called
CEMP-no class of objects.


title:
Dual Kinetic Balance Approach to the Dirac Equation for Axially
  Symmetric Systems: Application to Static and Time-Dependent Fields

abstract:
  Dual kinetic balance (DKB) technique was previously developed to eliminate
spurious states in the finite-basis-set-based solution of the Dirac equation in
central fields. In the present paper, it is extended to the Dirac equation for
systems with axial symmetry. The efficiency of the method is demonstrated by
the calculation of the energy spectra of hydrogenlike ions in presence of
static uniform electric or magnetic fields. In addition, the DKB basis set is
implemented to solve the time-dependent Dirac equation making use of the
split-operator technique. The excitation and ionization probabilities for the
hydrogenlike argon and tin ions exposed to laser pulses are evaluated.


title: Improving Frenet's Frame Using Bishop's Frame

abstract:
  The main drawback of the Frenet frame is that it is undefined at those points
where the curvature is zero. Further- more, in the case of planar curves, the
Frenet frame does not agree with the standard framing of curves in the plane.
The main drawback of the Bishop frame is that the principle normal vector N is
not in it. Our new frame, which we call the Beta frame, combines, on a large
set of curves, the best aspects of the Bishop frames and the Frenet frames. It
yields a globally defined normal, a globally defined signed curvature, and a
globally defined torsion. For planar curves it agrees with the standard framing
of curves in the plane.


title: On Shimura curves in the Torelli locus of curves

abstract:
  Oort has conjectured that there do not exist Shimura curves lying generically
in the Torelli locus of curves of genus $g \geq 8$. We show that there do not
exist one-dimensional Shimura families of semi-stable curves of genus $g\geq 5$
of Mumford type. We also show that there do not exist Shimura curves lying
generically in the Torelli locus of hyperelliptic curves of genus $g\geq 8$.
The first result proves a slightly weaker form of the conjecture for the case
of Shimura curves of Mumford type. The second result proves the conjecture for
the Torelli locus of hyperelliptic curves. We also present examples of Shimura
curves contained generically in the Torelli locus of curves of genus $3$ and
$4$.


title:
Potential Energy Landscapes for the 2D XY Model: Minima, Transition
  States and Pathways

abstract:
  We describe a numerical study of the potential energy landscape for the
two-dimensional XY model (with no disorder), considering up to 100 spins and
CPU and GPU implementations of local optimization, focusing on minima and
saddles of index one (transition states). We examine both periodic and
anti-periodic boundary conditions, and show that the number of stationary
points located increases exponentially with increasing lattice size. The
corresponding disconnectivity graphs exhibit funneled landscapes; the global
minima are readily located because they exhibit relatively large basins of
attraction compared to the higher energy minima as the lattice size increases.


title:
Effects of fermionic singlet neutrinos on high- and low-energy
  observables

abstract:
  In this doctoral thesis, we study both low- and high-energy observables
related to massive neutrinos. Neutrino oscillations have provided indisputable
evidence in favour of non-zero neutrino masses and mixings. However, the
original formulation of the Standard Model cannot account for these
observations, which calls for the introduction of new Physics. Among many
possibilities, we focus here on the inverse seesaw, a neutrino mass generation
mechanism in which the Standard Model is extended with fermionic gauge
singlets. This model offers an attractive alternative to the usual seesaw
realisations since it can potentially have natural Yukawa couplings
($\mathcal{O}(1)$) while keeping the new Physics scale at energies within reach
of the LHC. Among the many possible effects, this scenario can lead to
deviations from lepton flavour universality. We have investigated these
signatures and found that the ratios $R_K$ and $R_\pi$ provide new, additional
constraints on the inverse seesaw. We have also considered the embedding of the
inverse seesaw in supersymmetric models. This leads to increased rates for
various lepton flavour violating processes, due to enhanced contributions from
penguin diagrams mediated by the Higgs and $Z^0$ bosons. Finally, we also found
that the new invisible decay channels associated with the sterile neutrinos
present in the supersymmetric inverse seesaw could significantly weaken the
constraints on the mass and couplings of a light CP-odd Higgs boson.


title:
Analytical and numerical studies of disordered spin-1 Heisenberg chains
  with aperiodic couplings

abstract:
  We investigate the low-temperature properties of the one-dimensional spin-1
Heisenberg model with geometric fluctuations induced by aperiodic but
deterministic coupling distributions, involving two parameters. We focus on two
aperiodic sequences, the Fibonacci sequence and the 6-3 sequence. Our goal is
to understand how these geometric fluctuations modify the physics of the
(gapped) Haldane phase, which corresponds to the ground state of the uniform
spin-1 chain. We make use of different adaptations of the strong-disorder
renormalization-group (SDRG) scheme of Ma, Dasgupta and Hu, widely employed in
the study of random spin chains, supplemented by quantum Monte Carlo and
density-matrix renormalization-group numerical calculations, to study the
nature of the ground state as the coupling modulation is increased. We find no
phase transition for the Fibonacci chain, while we show that the 6-3 chain
exhibits a phase transition to a gapless, aperiodicity-dominated phase similar
to the one found for the aperiodic spin-1/2 XXZ chain. Contrary to what is
verified for random spin-1 chains, we show that different adaptations of the
SDRG scheme may lead to different qualitative conclusions about the nature of
the ground state in the presence of aperiodic coupling modulations.


title: A Survey of the Differential Geometry of Discrete Curves

abstract:
  Discretization of curves is an ancient topic. Even discretization of curves
with an eye toward differential geometry is over a century old. However there
is no general theory or methodology in the literature, despite the ubiquitous
use of discrete curves in mathematics and science. There are conflicting
definitions of even basic concepts such as discrete curvature {\kappa},
discrete torsion {\tau}, or discrete Frenet frame.


title: Hamiltonian chordal graphs are not cycle extendible

abstract:
  In 1990, Hendry conjectured that every Hamiltonian chordal graph is cycle
extendible; that is, the vertices of any non-Hamiltonian cycle are contained in
a cycle of length one greater. We disprove this conjecture by constructing
counterexamples on $n$ vertices for any $n \geq 15$. Furthermore, we show that
there exist counterexamples where the ratio of the length of a non-extendible
cycle to the total number of vertices can be made arbitrarily small. We then
consider cycle extendibility in Hamiltonian chordal graphs where certain
induced subgraphs are forbidden, notably $P_n$ and the bull.


title:
Geometric Compatibility of IceCube TeV-PeV Neutrino Excess and its
  Galactic Dark Matter Origin

abstract:
  We perform a geometric analysis for the sky map of the IceCube TeV-PeV
neutrino excess and test its compatibility with the sky map of decaying dark
matter signals in our galaxy. Using both Kolmogorov-Smirnov and the
likelihood-ratio tests, we have found that the observed event sky map prefers
to have a combination of the galactic dark matter and a homogeneous background
contributions, compared to a purely galactic dark matter origin. For the
assumption that the galactic dark matter is responsible for all neutrino
excess, the current data can also exclude a wide range of dark matter profiles
except flatter profiles such as the isothermal one. We also consider several
representative decaying dark matter spectra, which can provide a good fit to
the observed spectrum at IceCube with a dark matter lifetime of around 12
orders of magnitude longer than the age of the universe.


title:
Regularity of shadows and the geometry of the singular set associated to
  a Monge-Ampere equation

abstract:
  Illuminating the surface of a convex body with parallel beams of light in a
given direction generates a shadow region. We prove sharp regularity results
for the boundary of this shadow in every direction of illumination. Moreover,
techniques are developed for investigating the regularity of the region
generated by orthogonally projecting a convex set onto another. As an
application we study the geometry and Hausdorff dimension of the singular set
corresponding to a Monge-Ampere equation.