title:
Storage and retrieval of squeezing in multimode resonant quantum
  memories

abstract:
  In this article the ability to record, store, and read out the quantum
properties of light is studied. The discussion is based on high-speed and
adiabatic models of quantum memory in lambda-configuration and in the limit of
strong resonance. We show that in this case the equality between efficiency and
squeezing ratio, predicted by the simple beamsplitter model, is broken. The
requirement of the maximum squeezing in the output pulse should not be
accompanied by the requirement of maximum efficiency of memory, as in the
beamsplitter model. We have demonstrated a high output pulse squeezing, when
the efficiency reached only about 50%. Comprehension of this "paradox" is
achieved on the basis of mode analysis. The memories eigenmodes, which have an
impact on the memory process, are found numerically. Also, the spectral
analysis of modes was performed to match the spectral width of the input signal
to the capacities of the memories.


title:
Statistics of vortex loops emitted from quantum turbulence driven by an
  oscillating sphere

abstract:
  We perform numerical simulation of quantum turbulence at zero temperature
generated by an oscillating sphere. In this simulation, we injected vortices on
the sphere to generate turbulence. Although we prepare injected vortex loops of
identical length, they are extended by the oscillating sphere to form a tangle
through numerous reconnections. The resulting tangle around the sphere is
anisotropic and affected by the oscillation. The vortex tangle continues to
emit vortex loops, which leave the sphere. The statistics of emitted loops
differ significantly from those of the original injected vortices. First, the
sizes of the emitted loops are widely distributed, ranging from smaller to much
larger than the size of the initial injected loop. Second, the propagation
direction of the emitted loops exhibits anisotropy: Small loops move away
almost isotropically but large ones do so anisotropically along the oscillation
direction of the sphere. Thus, the oscillating object stirs the initial
injected vortices to reproduce a group of vortices with different statistics.
Such physics is compared with the experiments of vibrating objects.


title: Wind-Driven Evolution of White Dwarf Binaries to Type Ia Supernovae

abstract:
  In the single degenerate scenario for the progenitors of type Ia supernovae
(SNe Ia), a white dwarf rapidly accretes hydrogen- or helium-rich material from
its companion star, and appears as a supersoft X-ray source. This picture has
been challenged by the properties of the supersoft X-ray sources with very
low-mass companions and the observations of several nearby SNe Ia. It has been
pointed out that, the X-ray radiation or the wind from the accreting white
dwarf can excite wind or strip mass from the companion star, thus significantly
influence the mass transfer processes. In this paper we perform detailed
calculations of the wind-driven evolution of white dwarf binaries. We present
the parameter space for the possible SN Ia progenitors, and for the surviving
companions after the SNe. The results show that the ex-companion stars of SNe
Ia have characteristics more compatible with the observations, compared to
those in the traditional single degenerate scenario.


title:
M-dwarf stellar winds: the effects of realistic magnetic geometry on
  rotational evolution and planets

abstract:
  We perform three-dimensional numerical simulations of stellar winds of
early-M dwarf stars. Our simulations incorporate observationally reconstructed
large-scale surface magnetic maps, suggesting that the complexity of the
magnetic field can play an important role in the angular momentum evolution of
the star, possibly explaining the large distribution of periods in field dM
stars, as reported in recent works. In spite of the diversity of the magnetic
field topologies among the stars in our sample, we find that stellar wind
flowing near the (rotational) equatorial plane carries most of the stellar
angular momentum, but there is no preferred colatitude contributing to mass
loss, as the mass flux is maximum at different colatitudes for different stars.
We find that more non-axisymmetric magnetic fields result in more asymmetric
mass fluxes and wind total pressures $p_{\rm tot}$ (defined as the sum of
thermal, magnetic and ram pressures). Because planetary magnetospheric sizes
are set by pressure equilibrium between the planet's magnetic field and $p_{\rm
tot}$, variations of up to a factor of $3$ in $p_{\rm tot}$ (as found in the
case of a planet orbiting at several stellar radii away from the star) lead to
variations in magnetospheric radii of about 20 percent along the planetary
orbital path. In analogy to the flux of cosmic rays that impact the Earth,
which is inversely modulated with the non-axisymmetric component of the total
open solar magnetic flux, we conclude that planets orbiting M dwarf stars like
DT~Vir, DS~Leo and GJ~182, which have significant non-axisymmetric field
components, should be the more efficiently shielded from galactic cosmic rays,
even if the planets lack a protective thick atmosphere/large magnetosphere of
their own.


title: Graph measures and network robustness

abstract:
  Network robustness research aims at finding a measure to quantify network
robustness. Once such a measure has been established, we will be able to
compare networks, to improve existing networks and to design new networks that
are able to continue to perform well when it is subject to failures or attacks.
In this paper we survey a large amount of robustness measures on simple,
undirected and unweighted graphs, in order to offer a tool for network
administrators to evaluate and improve the robustness of their network. The
measures discussed in this paper are based on the concepts of connectivity
(including reliability polynomials), distance, betweenness and clustering. Some
other measures are notions from spectral graph theory, more precisely, they are
functions of the Laplacian eigenvalues. In addition to surveying these graph
measures, the paper also contains a discussion of their functionality as a
measure for topological network robustness.


title: Arveson's extension theorem in *-algebras

abstract:
  Arveson's extension theorem asserts that B(H) is an injective object in the
category of operator systems. Calling every self adjoint unital subspace of a
unital *-algebra, a quasi operator system, we show that Arveson's theorem
remains valid in the much larger category of quasi operator systems. This shows
that Arveson's theorem as a non commutative extension of Hahn-Banach theorem,
is of purely algebraic nature.


title: Some context-specific graphical models for discrete longitudinal data

abstract:
  Ron et al (1998) introduced a rich family of models for discrete longitudinal
data, called acyclic probabilistic finite automata. These may be described as
context-specific graphical models, since they are represented as directed
multigraphs that embody context-specific conditional independence relations.
Here we develop the methodology from a statistical modelling perspective. We
show how likelihood ratio tests may be constructed using standard contingency
table methods, and indicate how these may be used in model selection. We also
show that the models generalize certain subclasses of conventional undirected
and directed graphical models.


title: Multivariate Stirling Polynomials of the first and second kind

abstract:
  Two doubly indexed families of homogeneous and isobaric polynomials in
several indeterminates are considered: the (partial) exponential Bell
polynomials $B_{n,k}$ and a new family $S_{n,k}$ such that
$X_1^{-(2n-1)}S_{n,k}$ and $B_{n,k}$ obey an inversion law which generalizes
that of the Stirling numbers of the first and second kind. Both polynomial
families appear as Lie coefficients in expansions of certain derivatives of
higher order. Substituting $D^j(\varphi)$ (the $j$-th derivative of a fixed
function $\varphi$) in place of the indeterminates $X_j$ shows that both
$S_{n,k}$ and $B_{n,k}$ are differential polynomials depending on $\varphi$ and
on its inverse $\overline{\varphi}$, respectively. Some new light is shed
thereby on Comtet's solution of the Lagrange inversion problem in terms of the
Bell polynomials. According to Haiman and Schmitt that solution is essentially
the antipode on the Fa\`{a} di Bruno Hopf algebra. It can be represented by
$X_1^{-(2n-1)}S_{n,1}$. Moreover, a general expansion formula that holds for
the whole family $S_{n,k}$ ($1\leq k\leq n$) is established together with a
closed expression for the coefficients of $S_{n,k}$. Several important
properties of the Stirling numbers are demonstrated to be special cases of
relations between the corresponding polynomials. As a non-trivial example, a
Schl\"omilch-type formula is derived expressing $S_{n,k}$ in terms of the Bell
polynomials $B_{n,k}$, and vice versa.


title:
Gromov-Hausdorff stability of linkage-based hierarchical clustering
  methods

abstract:
  A hierarchical clustering method is stable if small perturbations on the data
set produce small perturbations in the result. These perturbations are measured
using the Gromov-Hausdorff metric. We study the problem of stability on
linkage-based hierarchical clustering methods. We obtain that, under some basic
conditions, standard linkage-based methods are semi-stable. This means that
they are stable if the input data is close enough to an ultrametric space. We
prove that, apart from exotic examples, introducing any unchaining condition in
the algorithm always produces unstable methods.


title:
Refinement of Robertson-type uncertainty principles with geometric
  interpretation

abstract:
  A generalisation of the classical covariance for quantum mechanical
observables has previously been presented by Gibilisco, Hiai and Petz.
Gibilisco and Isola has proved that the usual quantum covariance gives the
sharpest inequalities for the determinants of covariance matrices. We introduce
a new generalisation of the classical covariance which gives better
inequalities than the classical one furthermore it has a direct geometric
interpretation.


title:
Nuclear magnetic resonance study of thin Co$_2$FeAl$_{0.5}$Si$_{0.5}$
  Heusler films with varying thickness

abstract:
  Type, degree and evolution of structural order are important aspects for
understanding and controlling the properties of highly spin polarized Heusler
compounds, in particular with respect to the optimal film growth procedure. In
this work, we compare the structural order and the local magnetic properties
revealed by nuclear magnetic resonance (NMR) spectroscopy with the macroscopic
properties of thin Co$_2$FeAl$_{0.5}$Si$_{0.5}$ Heusler films with varying
thickness. A detailed analysis of the measured NMR spectra presented in this
paper enables us to find a very high degree of $L2_1$ type ordering up to 81%
concomitantly with excess Fe of 8 to 13% at the expense of Al and Si. We show,
that the formation of certain types of order do not only depend on the
thermodynamic phase diagrams as in bulk samples, but that the kinetic control
may contribute to the phase formation in thin films. It is an exciting finding
that Co$_2$FeAl$_{0.5}$Si$_{0.5}$ can form an almost ideal $L2_1$ structure in
films though with a considerable amount of Fe-Al/Si off-stoichiometry.
Moreover, the very good quality of the films as demonstrated by our NMR study
suggests that the novel technique of off-axis sputtering technique used to grow
the films sets stage for the optimized performance of
Co$_2$FeAl$_{0.5}$Si$_{0.5}$ in spintronic devices.


title:
Lattice QCD study of $B_s\to D_s \ell \bar\nu_\ell$ decay near zero
  recoil

abstract:
  We study the hadronic matrix elements describing the $B_s \to D_s\ell
\bar\nu_\ell$ decay in and beyond the Standard Model. By using the twisted mass
QCD on the lattice with $N_f=2$ dynamical flavors we compute the normalization
$\mathscr G_s(1)$ of the form factor dominating $B_s\to D_s \ell \bar\nu_\ell$
in the SM. We also make the first lattice determination of $F_0(q^2)/F_+(q^2)$
and $F_T(q^2)/F_+(q^2)$ near zero recoil (near $q^2_{\rm max}$). We briefly
discuss the non-strange case $B \to D\ell \bar\nu_\ell$ as well.


title: Inferring network topology via the propagation process

abstract:
  Inferring the network topology from the dynamics is a fundamental problem
with wide applications in geology, biology and even counter-terrorism. Based on
the propagation process, we present a simple method to uncover the network
topology. The numerical simulation on artificial networks shows that our method
enjoys a high accuracy in inferring the network topology. We find the infection
rate in the propagation process significantly influences the accuracy, and each
network is corresponding to an optimal infection rate. Moreover, the method
generally works better in large networks. These finding are confirmed in both
real social and nonsocial networks. Finally, the method is extended to directed
networks and a similarity measure specific for directed networks is designed.


title: Degenerate twistor spaces for hyperkahler manifolds

abstract:
  Let $M$ be a hyperkaehler manifold, and $\eta$ a closed, positive (1,1)-form
which is degenerate everywhere on $M$. We associate to $\eta$ a family of
complex structures on $M$, called a degenerate twistor family, and parametrized
by a complex line. When $\eta$ is a pullback of a Kaehler form under a
Lagrangian fibration $L$, all the fibers of degenerate twistor family also
admit a Lagrangian fibration, with the fibers isomorphic to that of $L$.
Degenerate twistor families can be obtained by taking limits of twistor
families, as one of the Kahler forms in the hyperkahler triple goes to $\eta$.


title:
Recent integral cross section validation measurements at the ASP
  facility

abstract:
  This work presents new integral data measured at the ASP 14 MeV neutron
irradiation facility at Aldermaston in the UK, which has recently become
available for fusion-related work through the CCFE materials programme.
Measurements of reaction products from activation experiments using elemental
foils were carried out using gamma spectrometry in a high efficiency,
high-purity germanium (HPGe) detector and associated digital signal processing
hardware. Following irradiation and rapid extraction to the measurement cell,
gamma emissions were acquired with both energy and time bins. Integral cross
section and half-life data have been derived from these measurements. Selected
integral cross section values are presented from the measurement campaigns.


title:
Design, manufacture and initial operation of the beryllium components of
  the JET ITER-like wall

abstract:
  The aim of the JET ITER-like Wall Project was to provide JET with the plasma
facing material combination now selected for the DT phase of ITER (bulk
beryllium main chamber limiters and a full tungsten divertor) and, in
conjunction with the upgraded neutral beam heating system, to achieve ITER
relevant conditions. The design of the bulk Be plasma facing components had to
be compatible with increased heating power and pulse length, as well as to
reuse the existing tile supports originally designed to cope with disruption
loads from carbon based tiles and be installed by remote handling. Risk
reduction measures (prototypes, jigs, etc) were implemented to maximize
efficiency during the shutdown. However, a large number of clashes with
existing components not fully captured by the configuration model occurred.
Restarting the plasma on the ITER-like Wall proved much easier than for the
carbon wall and no deconditioning by disruptions was observed. Disruptions have
been more threatening than expected due to the reduced radiative losses
compared to carbon, leaving most of the plasma magnetic energy to be conducted
to the wall and requiring routine disruption mitigation. The main chamber power
handling has achieved and possibly exceeded the design targets.


title:
Design of a mechanically actuated RF grounding system for the ITER ICRH
  antenna

abstract:
  In the ITER equatorial ports containing ICRH antennas, parasitic electrical
resonances can be excited in the nominal 20 mm clearance gap between the port
walls and the plug contained within it. RF calculations have established that
these resonances can be effectively mitigated by a series of suitably located
electrically conducting contacts between the port and plug. These contacts must
allow installation and removal of the antenna but must also make reliable
electrical contact during antenna operation. In addition, the contacts must be
compliant enough to survive deflection of the port during seismic and
disruption events without transmitting large forces to the vacuum vessel. The
distance to be spanned is subject to significant uncertainty, due to the large
manufacturing tolerances of the surrounding components, and this also must be
considered during the design process. This paper outlines progress made in the
design of the grounding system, as well as detailing a number of concepts which
have been investigated and abandoned, leading up to the current reference
design. The current reference design is a simple and robust mechanical solution
consisting of sprung Copper-plated Inconel flaps which use part of the range of
the shimming system included in the antenna design as the actuation mechanism.
This paper also details practical testing of a number of aspects of the design,
including building and testing a prototype to validate mechanical and thermal
analyses.


title:
A new class of indicators for the model selection of scaling laws in
  nuclear fusion

abstract:
  The development of computationally efficient model selection strategies
represents an important problem facing the analysis of Nuclear Fusion
experimental data, in particular in the field of scaling laws for the
extrapolation to future machines, and image processing. In this paper, a new
model selection indicator, named Model Falsification Criterion (MFC), will be
presented and applied to the problem of choosing the most generalizable scaling
laws for the power threshold to access the H-mode of confinement in Tokamaks.
The proposed indicator is based on the properties of the model residuals, their
entropy and an implementation of the data falsification principle. The model
selection ability of the proposed criterion will be demonstrated in comparison
with the most widely used frequentist (Akaike Information Criterion) and
bayesian (Bayesian Information Criterion) indicators.


title:
Investigating the use of nanofluids to improve high heat flux cooling
  systems

abstract:
  The thermal performance of high heat flux components in a fusion reactor
could be enhanced significantly by the use of nanofluid coolants, suspensions
of a liquid with low concentrations of solid nanoparticles. However, before
they are considered viable for fusion, the long-term behaviour of nanofluids
must be investigated. This paper reports an experiment which is being prepared
to provide data on nanofluid stability, settling and erosion in a HyperVapotron
device. Procedures are demonstrated for nanofluid synthesis and quality
assessment, and the fluid sample analysis methods are described. The end
results from this long-running experiment are expected to allow an initial
assessment of the suitability of nanofluids as coolants in a fusion reactor.


title:
Neutron-induced dpa, transmutations, gas production, and helium
  embrittlement of fusion materials

abstract:
  In a fusion reactor materials will be subjected to significant fluxes of
high-energy neutrons. As well as causing radiation damage, the neutrons also
initiate nuclear reactions leading to changes in the chemical composition of
materials (transmutation). Many of these reactions produce gases, particularly
helium, which cause additional swelling and embrittlement of materials. This
paper investigates, using a combination of neutron-transport and inventory
calculations, the variation in displacements per atom (dpa) and helium
production levels as a function of position within the high flux regions of a
recent conceptual model for the "next-step" fusion device DEMO. Subsequently,
the gas production rates are used to provide revised estimates, based on new
density-functional-theory results, for the critical component lifetimes
associated with the helium-induced grain-boundary embrittlement of materials.
The revised estimates give more optimistic projections for the lifetimes of
materials in a fusion power plant compared to a previous study, while at the
same time indicating that helium embrittlement remains one of the most
significant factors controlling the structural integrity of fusion power plant
components.


title:
Baryons in the relativistic jets of the stellar-mass black hole
  candidate 4U 1630-47

abstract:
  Accreting black holes are known to power relativistic jets, both in
stellar-mass binary systems and at the centres of galaxies. The power carried
away by the jets, and hence the feedback they provide to their surroundings,
depends strongly on their composition. Jets containing a baryonic component
should carry significantly more energy than electron-positron jets. While
energetic considerations and circular polarisation measurements have provided
conflicting circumstantial evidence for the presence or absence of baryons, the
only system in which baryons have been unequivocally detected in the jets is
the X-ray binary SS 433. Here we report the detection of Doppler-shifted X-ray
emission lines from a more typical black hole candidate X-ray binary,
4U1630-47, coincident with the reappearance of radio emission from the jets of
the source. We argue that these lines arise in a jet with velocity 0.66c,
thereby establishing the presence of baryons in the jet. Such baryonic jets are
more likely to be powered by the accretion disc rather than the spin of the
black hole, and if the baryons can be accelerated to relativistic speeds,
should be strong sources of gamma rays and neutrino emission.


title: Combining the Shortest Paths and the Bottleneck Paths Problems

abstract:
  We combine the well known Shortest Paths (SP) problem and the Bottleneck
Paths (BP) problem to introduce a new problem called the Shortest Paths for All
Flows (SP-AF) problem that has relevance in real life applications. We first
solve the Single Source Shortest Paths for All Flows (SSSP-AF) problem on
directed graphs with unit edge costs in $O(mn)$ worst case time bound. We then
present two algorithms to solve SSSP-AF on directed graphs with integer edge
costs bounded by $c$ in $O(m^2 + nc)$ and $O(m^2 + mn\log{(\frac{c}{m})})$ time
bounds. Finally we extend our algorithms for the SSSP-AF problem to solve the
All Pairs Shortest Paths for All Flows (APSP-AF) problem in $O(m^{2}n + nc)$
and $O(m^{2}n + mn^{2}\log{(\frac{c}{mn})})$ time bounds. All algorithms
presented in this paper are practical for implementation.


title: Characterization of an in-vacuum PILATUS 1M detector

abstract:
  A dedicated in-vacuum X-ray detector based on the hybrid pixel PILATUS 1M
detector has been installed at the four-crystal monochromator beamline of PTB
at the electron storage ring BESSY II in Berlin. Due to its windowless
operation, the detector can be used in the entire photon energy range of the
beamline from 10 keV down to 1.75 keV for small-angle X-ray scattering (SAXS)
experiments and anomalous SAXS (ASAXS) at absorption edges of light elements.
The radiometric and geometric properties of the detector like quantum
efficiency, pixel pitch and module alignment have been determined with low
uncertainties. The first grazing incidence SAXS (GISAXS) results demonstrate
the superior resolution in momentum transfer achievable at low photon energies.


title:
Higher dimensional multifractal analysis of non-uniformly hyperbolic
  systems

abstract:
  Johansson, Jordan, \"Oberg and Pollicott ( Israel J. Math.(2010)) has studied
the multifractal analysis of a class of one-dimensional non-uniformly
hyperbolic systems, by introducing some new techniques, we extend the results
to the case of high dimension.


title: Pearltrees as a tool for referencing and teaching

abstract:
  Pearltrees is a social service, using which people can organise Web contents,
photos and notes. These contents are the "pearls" on some trees. Besides the
social opportunities, the trees can be used as a tool to organise references
and for content curation. However, they can be helpful for teaching purposes
too.


title:
Beta-function for the Higgs self-interaction in the Standard Model at
  three-loop level

abstract:
  The discovery of a Higgs particle has triggered numerous theoretical and
experimental investigations concerning its production and decay rates and has
led to interesting results concerning its interaction with fermions and gauge
bosons. The self-interaction $\lambda$ of the Standard Model Higgs boson is
particularly important due to its close connection with the stability of the SM
vacuum. In this talk precision calculations for the evolution of this crucial
coupling are presented and their impact on the question of vacuum stability is
analysed. We also compare the theoretical precision resulting from the
calculation of three-loop $\beta$-functions to the experimental uncertainties
stemming from key parameters, such as the top mass, the Higgs mass and the
strong coupling, and to the theoretical uncertainties introduced by the
matching of experimental data to parameters in the theoretically favoured
$\overline{\text{MS}}$ renormalization scheme.


title:
Reconstructing the density and temperature structure of prestellar cores
  from $Herschel$ data: A case study for B68 and L1689B

abstract:
  Utilizing multi-wavelength dust emission maps acquired with $Herschel$, we
reconstruct local volume density and dust temperature profiles for the
prestellar cores B68 and L1689B using inverse-Abel transform based technique.
We present intrinsic radial dust temperature profiles of starless cores
directly from dust continuum emission maps disentangling the effect of
temperature variations along the line of sight which was previously limited to
the radiative transfer calculations. The reconstructed dust temperature
profiles show a significant drop in core center, a flat inner part, and a
rising outward trend until the background cloud temperature is reached. The
central beam-averaged dust temperatures obtained for B68 and L1689B are 9.3
$\pm$ 0.5 K and 9.8 $\pm$0.5 K, respectively, which are lower than the
temperatures of 11.3 K and 11.6 K obtained from direct SED fitting. The best
mass estimates derived by integrating the volume density profiles of B68 and
L1689B are 1.6 M_sol and 11 M_sol, respectively. Comparing our results for B68
with the near-infrared extinction studies, we find that the dust opacity law
adopted by the HGBS project, $\kappa_{\lambda} =0.1(\lambda/300 \mu m)^{-2}$,
agrees to within 50% with the dust extinction constraints


title:
A High Angular Resolution Survey of Massive Stars in Cygnus OB2: Results
  from the Hubble Space Telescope Fine Guidance Sensors

abstract:
  We present results of a high angular resolution survey of massive OB stars in
the Cygnus OB2 association that we conducted with the Fine Guidance Sensor 1R
(FGS1r) on the Hubble Space Telescope. FGS1r is able to resolve binary systems
with a magnitude difference delta-V < 4 down to separations as small as 0.01
arcsec. The sample includes 58 of the brighter members of Cyg OB2, one of the
closest examples of an environment containing a large number of very young and
massive stars. We resolved binary companions for 12 targets and confirmed the
triple nature of one other target, and we offer evidence of marginally resolved
companions for two additional stars. We confirm the binary nature of 11 of
these systems from complementary adaptive optics imaging observations. The
overall binary frequency in our study is 22% to 26% corresponding to orbital
periods ranging from 20 - 20,000 years. When combined with the known
short-period spectroscopic binaries, the results supports the hypothesis that
the binary fraction among massive stars is > 60%. One of the new discoveries is
a companion to the hypergiant star MT 304 = Cyg OB2-12, and future measurements
of orbital motion should provide mass estimates for this very luminous star.


title:
Challenges and opportunities of ZnO-related single crystalline
  heterostructures

abstract:
  Recent technological advancement in ZnO heterostructures has expanded the
possibility of device functionalities to various kinds of applications. In
order to extract novel device functionalities in the heterostructures, one
needs to fabricate high quality films and interfaces with minimal impurities,
defects, and disorder. With employing molecular-beam epitaxy (MBE) and single
crystal ZnO substrates, the density of residual impurities and defects can be
drastically reduced and the optical and electrical properties have been
dramatically improved for the ZnO films and heterostructures with MgxZn1-xO.
Here, we overview such recent technological advancement from various aspects of
application. Towards optoelectronic devices such as a light emitter and a
photodetector in an ultraviolet region, the development of p-type ZnO and the
fabrication of excellent Schottky contact, respectively, have been subjected to
intensive studies for years. For the former, the fine tuning of the growth
conditions to make MgxZn1-xO as intrinsic as possible has opened the
possibilities of making p-type MgxZn1-xO through NH3 doping method. For the
latter, conducting and transparent polymer films spin-coated on MgxZn1-xO was
shown to give almost ideal Schottky junctions. The wavelength-selective
detection can be realized with varying the Mg content. From the viewpoint of
electronic devices, two-dimensional electrons confined at the MgxZn1-xO/ZnO
interfaces are promising candidate for quantum devices because of high electron
mobility and strong electron-electron correlation effect. These wonderful
features and tremendous opportunities in ZnO-based heterostructures make this
system unique and promising in oxide electronics and will lead to new quantum
functionalities in optoelectronic devices and electronic applications with
lower energy consumption and high performance.


title: Spontaneous supersymmetry breaking in the 2d N=1 Wess-Zumino model

abstract:
  We study the phase diagram of the two-dimensional N=1 Wess-Zumino model using
Wilson fermions and the fermion loop formulation. We give a complete
non-perturbative determination of the ground state structure in the continuum
and infinite volume limit. We also present a determination of the particle
spectrum in the supersymmetric phase, in the supersymmetry broken phase and
across the supersymmetry breaking phase transition. In the supersymmetry broken
phase we observe the emergence of the Goldstino particle.


title: Algorithmic regularity for polynomials and applications

abstract:
  In analogy with the regularity lemma of Szemer\'edi, regularity lemmas for
polynomials shown by Green and Tao (Contrib. Discrete Math. 2009) and by
Kaufman and Lovett (FOCS 2008) modify a given collection of polynomials \calF =
{P_1,...,P_m} to a new collection \calF' so that the polynomials in \calF' are
"pseudorandom". These lemmas have various applications, such as (special cases)
of Reed-Muller testing and worst-case to average-case reductions for
polynomials. However, the transformation from \calF to \calF' is not
algorithmic for either regularity lemma. We define new notions of regularity
for polynomials, which are analogous to the above, but which allow for an
efficient algorithm to compute the pseudorandom collection \calF'. In
particular, when the field is of high characteristic, in polynomial time, we
can refine \calF into \calF' where every nonzero linear combination of
polynomials in \calF' has desirably small Gowers norm.
  Using the algorithmic regularity lemmas, we show that if a polynomial P of
degree d is within (normalized) Hamming distance 1-1/|F| -\eps of some unknown
polynomial of degree k over a prime field F (for k < d < |F|), then there is an
efficient algorithm for finding a degree-k polynomial Q, which is within
distance 1-1/|F| -\eta of P, for some \eta depending on \eps. This can be
thought of as decoding the Reed-Muller code of order k beyond the list decoding
radius (finding one close codeword), when the received word P itself is a
polynomial of degree d (with k < d < |F|).
  We also obtain an algorithmic version of the worst-case to average-case
reductions by Kaufman and Lovett. They show that if a polynomial of degree d
can be weakly approximated by a polynomial of lower degree, then it can be
computed exactly using a collection of polynomials of degree at most d-1. We
give an efficient (randomized) algorithm to find this collection.


title:
Geons found include non-susy CDM particle and non-singular "Kerr-Newman"
  models

abstract:
  The antisoliton-soliton {\cal G}={\cal S_-}\!\vee{\cal S_+} neutral state is
a proper geon in a family of stable squashed-S^3\times\IR pp-wave electrovacua
along a primordial Q/r^2 field. With {\cal S_-} propagating backwards in time,
the dominant EM field is that of an effective electric-dipole moment {\sf p}.
If disjointed, the {\cal S_\pm} carry \pm Q charge (on a round-S^2 {\em
physical} singularity of radius r_o) as non-singular alternatives to the
Kerr-Newman solution. {\cal G} has three scales (gravitational \kappa, metric
scale, NUT-charge \kappa Q=2r_o) in a full 4-scale hierarchy without
supersymmetry. A particular {\cal G} with effective mass and a near-zero {\sf
p} is proposed as dark-matter particle. A gas of such {\cal G}s would
`freeze-out' before the electroweak era as CDM, whose present mean density is
predicted by this model (via Casimir-effect data on earth) as, roughly, 100{\rm
Mev}/{\rm cm}^3.


title:
Testing metallicity indicators at z~1.4 with the gravitationally lensed
  galaxy CASSOWARY 20

abstract:
  We present X-shooter observations of CASSOWARY 20 (CSWA 20), a star-forming
(SFR ~6 Msol/yr) galaxy at z=1.433, magnified by a factor of 11.5 by the
gravitational lensing produced by a massive foreground galaxy at z=0.741. We
analysed the integrated physical properties of the HII regions of CSWA 20 using
temperature- and density-sensitive emission lines. We find the abundance of
oxygen to be ~1/7 of solar, while carbon is ~50 times less abundant than in the
Sun. The unusually low C/O ratio may be an indication of a particularly rapid
timescale of chemical enrichment. The wide wavelength coverage of X-shooter
gives us access to five different methods for determining the metallicity of
CSWA 20, three based on emission lines from HII regions and two on absorption
features formed in the atmospheres of massive stars. All five estimates are in
agreement, within the factor of ~2 uncertainty of each method. The interstellar
medium of CSWA 20 only partially covers the star-forming region as viewed from
our direction; in particular, absorption lines from neutrals and first ions are
exceptionally weak. We find evidence for large-scale outflows of the
interstellar medium (ISM) with speeds of up 750 km/s, similar to the values
measured in other high-z galaxies sustaining much higher rates of star
formation.


title: Thermal vacancies in close-packing solids

abstract:
  Based on Stillinger's version of cell cluster theory, we derive an expression
for the equilibrium concentration of thermal monovacancies in solids which
allows for a transparent interpretation of the vacancy volume and the
energetic/entropic part in the corresponding Gibbs energy of vacancy formation
$\Delta G_{\rm v}$. For the close--packing crystals of the hard sphere and
Lennard--Jones model systems very good agreement with simulation data is found.
Application to metals through the embedded--atom method (EAM) reveals a strong
sensitivity of the variation of $\Delta G_{\rm v}$ with temperature to details
of the EAM potential. Our truncation of the cell cluster series allows for an
approximate, but direct measurement of crystal free energies and vacancy
concentration in colloidal model systems using laser tweezers.


title:
On stochastic generation of ultrametrics in high-dimension Euclidean
  spaces

abstract:
  The proof of the theorem, which states that the Euclidean metric on the set
of random points in an $n$-dimensional Euclidean space with the distribution of
a special class, converges in probability in the limit $n\rightarrow\infty$ to
the ultrametric is presented. The values of the ultrametric distance matrix is
completely determined by variances of point coordinates. Probabilistic
algorithm for the generation of finite ultrametric structures of any topology
in high-dimensional Euclidean space is presented. The validity of the algorithm
is demonstrated by explicit calculations of distance matrices with fixed
dimensions and ultrametricity indexes for various dimensions of Euclidean
space.


title: The elastodynamic model of wave-telegraph type for quasicrystals

abstract:
  In this work we propose the elastodynamic model of wave-telegraph type for
the description of dynamics of quasicrystals. Phonons are represented by waves,
and phasons by waves damped in time and propagating with finite velocity.
Therefore, the equations of motion for the phonon fields are of wave type and
for the phason fields are of telegraph type. The proposed model constitutes a
unified theory in the sense that already established models in the literature
can be recovered as asymptotic cases of it. The equations of motion for the
displacement fields in the theory of incompatible and compatible elastodynamics
of wave-telegraph type of quasicrystals are derived.


title: Microvariability Detection of Mrk 421

abstract:
  The BL Lac object Mrk 421 was observed in optical bands from 2009 April to
2012 May with the 1.0 m telescope at Weihai Observatory of Shandong University.
Microvariability was analysed by C and F tests, but no significant
microvariability was detected during our observations.


title: Non-K\"ahler Expanding Ricci Solitons II

abstract:
  We produce new non-K\"ahler, non-Einstein, complete expanding gradient Ricci
solitons with conical asymptotics and underlying manifold of the form $\R^2
\times M_2 \times \cdots \times M_r$, where $r \geq 2$ and $M_i$ are arbitrary
closed Einstein spaces with positive scalar curvature. We also find numerical
evidence for complete expanding solitons on the vector bundles whose sphere
bundles are the twistor or ${\rm Sp}(1)$ bundles over quaternionic projective
space.


title: Subgaussian 1-cocycles on discrete groups

abstract:
  We prove the $L_p$ Poincar\'e inequalities with constant $C\sqrt{p}$ for
$1$-cocycles on countable discrete groups under Bakry--Emery's
$\Gamma_2$-criterion. These inequalities determine an analogue of subgaussian
behavior for 1-cocycles. Our theorem improves some of our previous results in
this direction, and in particular implies Efraim and Lust-Piquard's Poincar\'e
type inequalities for the Walsh system. The key new ingredient in our proof is
a decoupling argument. As complementary results, we also show that the spectral
gap inequality implies the $L_p$ Poincar\'e inequalities with constant $C{p}$
under some conditions in the noncommutative setting. New examples which satisfy
the $\Gamma_2$-criterion are provided as well.


title:
The acceleration of the Universe in the light of supernovae -- The key
  role of the Cerro Tololo Inter-American Observatory

abstract:
  The discovery of acceleration and dark energy arguably constitutes the most
revolutionary discovery in astrophysics in recent years. Cerro Tololo
Inter-American Observatory (CTIO) played a key role in this amazing discovery
through three systematic supernova surveys organized by staff astronomers: the
"Tololo Supernova Program" (1986-2000), the Calan/Tololo Project (1989-1993),
and the "High-Z Supernova Search Team" (1994-1998). CTIO's state of the art
instruments also were fundamental in the independent discovery of acceleration
by the "Supernova Cosmology Project" (1992-1999). Here I summarize the work on
supernovae carried out from CTIO that led to the discovery of acceleration and
dark energy and provide a brief historical summary on the use of Type Ia
supernovae in cosmology in order to provide context for the CTIO contribution.


title:
Low-Lying Excitation Modes of Trapped Dipolar Fermi Gases: From
  Collisionless to Hydrodynamic Regime

abstract:
  By means of the Boltzmann-Vlasov kinetic equation we investigate dynamical
properties of a trapped, one-component Fermi gas at zero temperature, featuring
the anisotropic and long-range dipole-dipole interaction. To this end, we
determine an approximate solution by rescaling both space and momentum
variables of the equilibrium distribution, thereby obtaining coupled ordinary
differential equations for the corresponding scaling parameters. Based on
previous results on how the Fermi sphere is deformed in the hydrodynamic regime
of a dipolar Fermi gas, we are able to implement the relaxation-time
approximation for the collision integral. Then, we proceed by linearizing the
equations of motion around the equilibrium in order to study both the
frequencies and the damping of the low-lying excitation modes all the way from
the collisionless to the hydrodynamic regime. Our theoretical results are
expected to be relevant for understanding current experiments with trapped
dipolar Fermi gases.


title: Copulas and time series with long-ranged dependences

abstract:
  We review ideas on temporal dependences and recurrences in discrete time
series from several areas of natural and social sciences. We revisit existing
studies and redefine the relevant observables in the language of copulas (joint
laws of the ranks). We propose that copulas provide an appropriate mathematical
framework to study non-linear time dependences and related concepts - like
aftershocks, Omori law, recurrences, waiting times. We also critically argue
using this global approach that previous phenomenological attempts involving
only a long-ranged autocorrelation function lacked complexity in that they were
essentially mono-scale.


title: Breaking the quadratic barrier for 3-LCCs over the Reals

abstract:
  We prove that 3-query linear locally correctable codes over the Reals of
dimension $d$ require block length $n>d^{2+\lambda}$ for some fixed, positive
$\lambda >0$. Geometrically, this means that if $n$ vectors in $R^d$ are such
that each vector is spanned by a linear number of disjoint triples of others,
then it must be that $n > d^{2+\lambda}$. This improves the known quadratic
lower bounds (e.g. {KdW04, Wood07}). While a modest improvement, we expect that
the new techniques introduced in this work will be useful for further progress
on lower bounds of locally correctable and decodable codes with more than 2
queries, possibly over other fields as well.
  Our proof introduces several new ideas to existing lower bound techniques,
several of which work over every field. At a high level, our proof has two
parts, {\it clustering} and {\it random restriction}.
  The clustering step uses a powerful theorem of Barthe from convex geometry.
It can be used (after preprocessing our LCC to be {\it balanced}), to apply a
basis change (and rescaling) of the vectors, so that the resulting unit vectors
become {\it nearly isotropic}. This together with the fact that any LCC must
have many `correlated' pairs of points, lets us deduce that the vectors must
have a surprisingly strong geometric clustering, and hence also combinatorial
clustering with respect to the spanning triples.
  In the restriction step, we devise a new variant of the dimension reduction
technique used in previous lower bounds, which is able to take advantage of the
combinatorial clustering structure above. The analysis of our random projection
method reduces to a simple (weakly) random graph process, and works over any
field.


title: One- and two-neutron halos in effective field theory

abstract:
  I discuss recent work our group has undertaken on effective-field-theory
analyses of experimental data pertaining to one- and two-neutron halo nuclei.


title:
Study of the discovery potential for hidden photon emission at future
  electron scattering fixed target experiments

abstract:
  Electron scattering fixed target experiments are a versatile tool to explore
various physics phenomena. Recently these experiments came into focus to search
for $U(1)$ extensions of the Standard Model of particle physics at low
energies. These extensions are motivated from anomalies in astrophysical
observations as well as from deviations from Standard Model predictions, such
as the discrepancy between the experimental and theoretical determination of
the anomalous magnetic moment of the muon. They also arise naturally when the
Standard Model is embedded into a more general theory. In the considered $U(1)$
extensions a new, light messenger particle $\gamma^\prime$, the hidden photon,
couples to the hidden sector as well as to the electromagnetic current of the
Standard Model by kinetic mixing, which allows for a search for this particle
e.g. in the invariant mass distribution of the process $e (A,\,Z)\rightarrow e
(A,\,Z) l^+ l^-$. In this process the hidden photon is emitted by
bremsstrahlung and decays into a pair of Standard Model leptons. In this work
we study the applicability of the Weizs\"acker-Williams approximation to
calculate the signal cross section of the process, which is widely used to
design such experimental setups. Furthermore, based on a previous work, we
investigate the discovery potential of future experimental setups at the
Jefferson Lab. For that purpose we simulate the relevant cross sections for the
signal and the QED background in the actual kinematical setups and obtain
projected exclusion limits.


title: On positive proportion of rank zero twists of elliptic curves over Q

abstract:
  Extending the idea of \cite{dab2} and using the 2-descent method, we provide
three general families of elliptic curves over Q such that a positive
proportion of prime-twists of such elliptic curves have rank zero
simultaneously.


title: An analysis of $H \to \gamma \gamma$ up to three-loop QCD corrections

abstract:
  The principle of maximum conformality (PMC) provides a convenient way for
setting the optimal renormalization scales for high-energy processes, which can
eliminate the conventional renormalization scale error via an order-by-order
manner. At present, we make a detailed PMC analysis on the Higgs decay
$H\rightarrow \gamma\gamma$ up to three-loop QCD corrections. As an important
point of deriving reliable PMC estimation, it is noted that only those
$\{\beta_i\}$-terms that rightly determine the running behavior of coupling
constant via the renormalization group equation should be absorbed into the
coupling constant, and those $\{\beta_i\}$-terms that pertain to the quark mass
renormalization and etc. should be kept as a separate. To avoid confusion of
separating and absorbing different types of $\{\beta_i\}$-terms into the
coupling constant, we first transform the decay width in terms of top quark
$\overline{\rm MS}$ mass into that of on-shell mass and then apply the PMC
scale setting. After applying PMC scale setting, the final estimation is
conformal and is scheme-independent and scale-independent. Up to three-loop QCD
corrections, we obtain a PMC scale $\mu^{\rm PMC}_{r}=242.3$ GeV $\sim 2M_H$,
which is optimal and highly independent of any choice of initial scale. Thus,
we obtain a more accurate scale-independent prediction by taking the Higgs mass
as the same as that of ATLAS and CMS measurements, i.e., $\Gamma(H\rightarrow
\gamma\gamma)|_{\rm ATLAS}=9.504^{+0.226}_{-0.252}$ keV and
$\Gamma(H\rightarrow \gamma\gamma)|_{\rm CMS}=9.568^{+0.195}_{-0.191}$ keV,
where the error is caused by the measured Higgs mass, i.e. the Higgs mass
$M_{H}$ is taken as $125.5\pm0.2^{+0.5}_{-0.6}$ GeV for ATLAS and
$125.7\pm0.3\pm0.3$ GeV for CMS, respectively.


title: Factorization in the self-idealization of a PID

abstract:
  Let $D$ be a principal ideal domain and $R(D) = \{\begin{pmatrix} a & b 0 & a
\end{pmatrix} \mid a, b \in D\}$ be its self-idealization. It is known that
$R(D)$ is a commutative noetherian ring with identity, and hence $R(D)$ is
atomic (i.e., every nonzero nonunit can be written as a finite product of
irreducible elements). In this paper, we completely characterize the
irreducible elements of $R(D)$. We then use this result to show how to
factorize each nonzero nonunit of $R(D)$ into irreducible elements. We show
that every irreducible element of $R(D)$ is a primary element, and we determine
the system of sets of lengths of $R(D)$.


title:
A Methodology to Engineer and Validate Dynamic Multi-level Multi-agent
  Based Simulations

abstract:
  This article proposes a methodology to model and simulate complex systems,
based on IRM4MLS, a generic agent-based meta-model able to deal with
multi-level systems. This methodology permits the engineering of dynamic
multi-level agent-based models, to represent complex systems over several
scales and domains of interest. Its goal is to simulate a phenomenon using
dynamically the lightest representation to save computer resources without loss
of information. This methodology is based on two mechanisms: (1) the activation
or deactivation of agents representing different domain parts of the same
phenomenon and (2) the aggregation or disaggregation of agents representing the
same phenomenon at different scales.


title: M-theory and Type IIB from a Duality Manifest Action

abstract:
  We revisit the SL(5) U-duality manifest action constructed by Berman and
Perry in an extended spacetime. Upon choosing a four-dimensional solution to
the section condition constraint, the theory reduces to a four-dimensional
truncation of eleven-dimensional supergravity. In this paper, we show that the
theory contains more than this M-theory reduction. The section condition also
admits an SL(5) inequivalent three-dimensional solution, upon which the action
directly reduces to a three-dimensional truncation of type IIB supergravity. We
also discuss the reduction to IIB$^*$ supergravity.


title: Spin Waves and Dielectric Softening of Polar Molecule Condensates

abstract:
  We consider an oblate Bose-Einstein condensate of heteronuclear polar
molecules in a weak applied electric field. This system supports a rich
quasiparticle spectrum that plays a critical role in determining its bulk
dielectric properties. In particular, in sufficiently weak fields the system
undergoes a polarization wave rotonization, leading to the development of
textured electronic structure and a dielectric instability that is
characteristic of the onset of a negative static dielectric function.


title: Supersymmetric quiver gauge theories on the lattice

abstract:
  In this paper we detail the lattice constructions of several classes of
supersymmetric quiver gauge theories in two and three Euclidean spacetime
dimensions possessing exact supersymmetry at finite lattice spacing. Such
constructions are obtained through the methods of topological twisting and
geometric discretization of Euclidean Yang--Mills theories with eight and
sixteen supercharges in two and three dimensions. We detail the lattice
constructions of two-dimensional quiver gauge theories possessing four and
eight supercharges and three-dimensional quiver gauge theories possessing eight
supercharges.


title: Crossover transition to quark matter in heavy hybrid stars

abstract:
  We study the possibility that the transition from hadron matter to quark
matter at vanishing temperatures proceeds via crossover, similar to the
crossover behavior found with lattice QCD studies at high temperatures. The
purpose is to examine astrophysical consequences of this postulate by
constructing hybrid star sequences fulfilling current experimental data.


title: Systems described by Volterra type integral operators

abstract:
  In the paper some sufficient condition for the nonlinear integral operator of
the Volterra type to be a diffeomorphism defined on the space of absolutely
continuous functions are formulated. The proof relies on consideration of the
linearized equation together with Palais-Smale condition, thus a combination of
topological and variational methods is used. The applications of the result to
the control systems with feedback and to the specific nonlinear Volterra
equation are presented.


title:
A Dynamic Clustering and Resource Allocation Algorithm for Downlink CoMP
  Systems with Multiple Antenna UEs

abstract:
  Coordinated multi-point (CoMP) schemes have been widely studied in the recent
years to tackle the inter-cell interference. In practice, latency and
throughput constraints on the backhaul allow the organization of only small
clusters of base stations (BSs) where joint processing (JP) can be implemented.
In this work we focus on downlink CoMP-JP with multiple antenna user equipments
(UEs) and propose a novel dynamic clustering algorithm. The additional degrees
of freedom at the UE can be used to suppress the residual interference by using
an interference rejection combiner (IRC) and allow a multistream transmission.
In our proposal we first define a set of candidate clusters depending on
long-term channel conditions. Then, in each time block, we develop a resource
allocation scheme by jointly optimizing transmitter and receiver where: a)
within each candidate cluster a weighted sum rate is estimated and then b) a
set of clusters is scheduled in order to maximize the system weighted sum rate.
Numerical results show that much higher rates are achieved when UEs are
equipped with multiple antennas. Moreover, as this performance improvement is
mainly due to the IRC, the gain achieved by the proposed approach with respect
to the non-cooperative scheme decreases by increasing the number of UE
antennas.


title: Calculations for OPF with Adjustable Tap Ratios

abstract:
  In this document, the calculations of the AC power balance and flow equations
used by MATPOWER will be extended to include adjustable tap ratios.


title:
An Observational Evaluation of Magnetic Confinement in the Winds of BA
  Supergiants

abstract:
  Magnetic wind confinement has been proposed as one explanation for the
complex wind structures of supergiant stars of spectral types B and A.
Observational investigation of this hypothesis was undertaken using
high-resolution ({\lambda}/{\Delta}{\lambda} {\sim} 65,000) circular
polarization (Stokes V ) spectra of six late B and early A type supergiants
({\beta} Ori, B8Iae; 4 Lac, B9Iab; {\eta} Leo, A0Ib; HR1040, A0Ib; {\alpha}
Cyg, A2Iae; {\nu} Cep, A2Iab), obtained with the instruments ESPaDOnS and
Narval at the Canada-France-Hawaii Telescope and the Bernard Lyot Telescope.
Least Squares Deconvolution (LSD) analysis of the Stokes V spectra of all stars
yields no evidence of a magnetic field, with best longitudinal field 1{\sigma}
error bars ranging from {\sim}0.5 to {\sim}4.5 G for most stars. Spectrum
synthesis analysis of the LSD profiles using Bayesian inference yields an upper
limit with 95.4% credibility on the polar strength of the (undetected) surface
dipole fields of individual stars ranging from 3 to 30 G. These results
strongly suggest that magnetic wind confinement due to organized dipolar
magnetic fields is not the origin of the wind variability of BA supergiant
stars. Upper limits for magnetic spots may also be inconsistent with magnetic
wind confinement in the limit of large spot size and filling factor, depending
on the adopted wind parameters. Therefore, if magnetic spots are responsible
for the wind variability of BA supergiant stars, they likely occupy a small
fraction of the photosphere.


title:
Insulator-to-Superconductor Transition upon Electron Doping in a
  BiS$_{2}$-Based Superconductor Sr$_{1-x}$La$_{x}$FBiS$_{2}$

abstract:
  Effects of electron doping on the BiS$_2$-based superconductors
Sr$_{1-x}$La$_x$FBiS$_2$ ($0\le x\le 0.6$) have been investigated using the
systematically synthesized polycrystals. The pristine compound is a band
insulator with the BiS$_2$ layer, which accommodates electron carriers through
the La substitution for Sr, as evidenced by the change in x-ray absorption
spectra reflecting the occupancy of Bi 6$p$ orbitals. With increasing the
carrier density, the resistivity progressively decreases and a bad metallic
state appears for $x\ge0.45$, where bulk superconductivity manifests itself
below approximately 3 K. The value of $T_{\rm c}$ gradually increases with
decreasing $x$ from 0.6 to 0.45 and immediately decreases down to zero at the
critical concentration of $x\sim 0.4$, resulting in an insulator-superconductor
transition highly sensitive to the carrier density. Thermodynamic measurements
furthermore have revealed the possible enhancement of the superconducting
coupling strength as the insulating phase is approached. The obtained
superconducting phase diagram is markedly different from the broad dome-shaped
superconducting phase previously reported for $R$O$_{1-x}$F$_x$BiS$_2$ ($R$:
rare-earth ion), suggesting a strong influence of the blocking layer on the
superconductivity. Instead all these features are similar to those observed in
Li-intercalated ZrNCl superconductor, except for the critical electron
concentration of as low as 6% in the latter compound. For the present
superconductor, notably, the existence of hole-type carriers has been indicated
in the normal state from the Hall effect measurements. The
Sr$_{1-x}$La$_x$FBiS$_2$ system providing the phase diagram for the rigid-band
doping in the BiS$_2$ layer would be another prototypical example of
superconductivity derived from a doped layered band insulator, hosting both
hole-like and electron-like Fermi surfaces.


title: Mass Measurements of Stellar and Intermediate Mass Black-Holes

abstract:
  We discuss the method, and potential systematic effects therein, used for
measuring the mass of stellar-mass black holes in X-ray binaries. We restrict
our discussion to the method that relies on the validity of Kepler's laws; we
refer to this method as the dynamical method. We briefly discuss the
implications of the mass distribution of stellar-mass black holes and provide
an outlook for future measurements. Further, we investigate the evidence for
the existence of intermediate-mass black holes i.e. black holes with masses
above 100 Msun, the limit to the black hole mass that can be produced by
stellar evolution in the current Universe.


title: On higher spin extension of the Jackiw-Teitelboim gravity model

abstract:
  We formulate AdS_2 higher spin gravity as BF theory with fields taking values
in sl(N,R) algebra treated as higher spin algebra. The theory is topological
and naturally extends the Jackiw-Teitelboim gravity model so as to include
higher spin fields. The BF equations linearized about AdS_2 background are
interpreted as describing higher spin partially-massless fields of maximal
depth along with dilaton fields. It is shown that there are dual metric-like
formulations following from the original linearized BF higher spin theory. The
duality establishes a dynamical equivalence of the metric-like field equations
that can be given either as massive scalar field equations or as conservation
conditions for higher spin currents.


title: Actuarial fairness and solidarity in pooled annuity funds

abstract:
  Various types of structures that enable a group of individuals to pool their
mortality risk have been proposed in the literature. Collectively, the
structures are called pooled annuity funds. Since the pooled annuity funds
propose different methods of pooling mortality risk, we investigate the
connections between them and find that they are genuinely different for a
finite heterogeneous membership profile.
  We discuss the importance of actuarial fairness, defined as the expected
benefits equalling the contributions for each member, in the context of pooling
mortality risk and comment on whether actuarial unfairness can be seen as
solidarity between members. We show that, with a finite number of members in
the fund, the group self-annuitization scheme is not actuarially fair: some
members subsidize the other members. The implication is that the members who
are subsidizing the others may obtain a higher expected benefit by joining a
fund with a more favourable membership profile. However, we find that the
subsidies are financially significant only for very small or highly
heterogeneous membership profiles.


title: Finite element approximation of the $p(\cdot)$-Laplacian

abstract:
  We study a~priori estimates for the Dirichlet problem of the
$p(\cdot)$-Laplacian, \[-\mathrm{div}(|\nabla v|^{p(\cdot)-2} \nabla v) = f. \]
We show that the gradients of the finite element approximation with zero
boundary data converges with rate $O(h^\alpha)$ if the exponent $p$ is
$\alpha$-H\"{o}lder continuous. The error of the gradients is measured in the
so-called quasi-norm, i.e. we measure the $L^2$-error of $|\nabla
v|^{\frac{p-2}{2}} \nabla v$.


title:
The Mazurkiewicz distance and sets that are finitely connected at the
  boundary

abstract:
  We study local connectedness, local accessibility and finite connectedness at
the boundary, in relation to the compactness of the Mazurkiewicz completion of
a bounded domain in a metric space. For countably connected planar domains we
obtain a complete characterization. It is also shown exactly which parts of
this characterization fail in higher dimensions and in metric spaces.


title:
Human Mobility and Predictability enriched by Social Phenomena
  Information (extended abstract)

abstract:
  The information collected by mobile phone operators can be considered as the
most detailed information on human mobility across a large part of the
population. The study of the dynamics of human mobility using the collected
geolocations of users, and applying it to predict future users' locations, has
been an active field of research in recent years. In this work, we study the
extent to which social phenomena are reflected in mobile phone data, focusing
in particular in the cases of urban commute and major sports events. We
illustrate how these events are reflected in the data, and show how information
about the events can be used to improve predictability in a simple model for a
mobile phone user's location.


title: Reducing disorder in graphene nanoribbons by chemical edge modification

abstract:
  We present electronic transport measurements on etched graphene nanoribbons
on silicon dioxide before and after a short hydrouoric acid (HF) treatment. We
report on changes in the transport properties, in particular, in terms of a
decreasing transport gap and a reduced doping level after HF dipping.
Interestingly, the effective energy gap is nearly unaffected by the HF
treatment. Additional measurements on a graphene nanoribbon with lateral
graphene gates support strong indications that the HF significantly modifies
the edges of the investigated nanoribbons leading to a significantly reduced
disorder potential in these graphene nanostructures.


title: On conformal divergences and their population minimizers

abstract:
  Total Bregman divergences are a recent tweak of ordinary Bregman divergences
originally motivated by applications that required invariance by rotations.
They have displayed superior results compared to ordinary Bregman divergences
on several clustering, computer vision, medical imaging and machine learning
tasks. These preliminary results raise two important problems : First, report a
complete characterization of the left and right population minimizers for this
class of total Bregman divergences. Second, characterize a principled superset
of total and ordinary Bregman divergences with good clustering properties, from
which one could tailor the choice of a divergence to a particular application.
In this paper, we provide and study one such superset with interesting
geometric features, that we call conformal divergences, and focus on their left
and right population minimizers. Our results are obtained in a recently coined
$(u, v)$-geometric structure that is a generalization of the dually flat affine
connections in information geometry. We characterize both analytically and
geometrically the population minimizers. We prove that conformal divergences
(resp. total Bregman divergences) are essentially exhaustive for their left
(resp. right) population minimizers. We further report new results and extend
previous results on the robustness to outliers of the left and right population
minimizers, and discuss the role of the $(u, v)$-geometric structure in
clustering. Additional results are also given.


title:
Visual Representation of 3D Language Constructs Specified by Generic
  Depictions

abstract:
  Several modeling domains make use of three-dimensional representations, e.g.,
the "ball-and-stick" models of molecules. Our generator framework DEViL3D
supports the design and implementation of visual 3D languages for such modeling
purposes. The front-end of a language implementation generated by DEViL3D is a
dedicated 3D graphical structure editor, which is used to construct programs in
that domain. DEViL3D supports the language designer to describe the visual
appearance of the constructs of the particular language in terms of generic 3D
depictions. Their parameters specify where substructures are embedded, and how
the graphic adapts to space requirements of nested constructs. The 3D editor
used for such specifications is generated by DEViL3D, too. In this paper, we
briefly introduce the research field of 3D visual languages and report about
our generator framework and the role that generic depictions play in the
specification process for 3D languages. Our results show that our approach is
suitable for a wide range of 3D languages. We emphasize this suitability by
presenting requirements on the visual appearance for different languages.


title: Commutation Relations for Unitary Operators

abstract:
  Let $U$ be a unitary operator defined on some infinite-dimensional complex
Hilbert space ${\cal H}$. Under some suitable regularity assumptions, it is
known that a local positive commutation relation between $U$ and an auxiliary
self-adjoint operator $A$ defined on ${\cal H}$ allows to prove that the
spectrum of $U$ has no singular continuous spectrum and a finite point
spectrum, at least locally. We show that these conclusions still hold under
weak regularity hypotheses and without any gap condition. As an application, we
study the spectral properties of the Floquet operator associated to some
perturbations of the quantum harmonic oscillator under resonant AC-Stark
potential.


title: Formation and interaction of resonance chains in the open 3-disk system

abstract:
  In ballistic open quantum systems one often observes that the resonances in
the complex-energy plane form a clear chain structure. Taking the open 3-disk
system as a paradigmatic model system, we investigate how this chain structure
is reflected in the resonance states and how it is connected to the underlying
classical dynamics. Using an efficient scattering approach we observe that
resonance states along one chain are clearly correlated while resonance states
of different chains show an anticorrelation. Studying the phase space
representations of the resonance states we find that their localization in
phase space oscillate between different regions of the classical trapped set as
one moves along the chains and that these oscillations are connected to a
modulation of the resonance spacing. A single resonance chain is thus no WKB
quantization of a single periodic orbits, but the structure of several
oscillating chains arises from the interaction of several periodic orbits. We
illuminate the physical mechanism behind these findings by combining the
semiclassical cycle expansion with a quantum graph model.


title: Random matrices and Lyapunov coefficients regularity

abstract:
  Analyticity and other properties of the largest or smallest Lyapunov exponent
of a product of real matrices with a "cone property" are studied as functions
of the matrices entries, as long as they vary without destroying the cone
property. The result is applied to stability directions, Lyapunov coefficients
and Lyapunov exponents of a class of products of random matrices and of
dynamical systems. The method is based on the classical theory of the Mayer
series in Statistical Mechanics of rarefied gases.


title: Strain-induced insulator-to-metal transition in LaTiO3 within DFT+DMFT

abstract:
  We present results of combined density functional theory plus dynamical
mean-field theory (DFT+DMFT) calculations, which show that the Mott insulator
LaTiO3 undergoes an insulator-to-metal transition under compressive epitaxial
strain of about -2%. This transition is driven by strain-induced changes in the
crystal-field splitting between the Ti t2g orbitals, which in turn are
intimately related to the collective tilts and rotations of the oxygen
octahedra in the orthorhombically distorted Pbnm perovskite structure. An
accurate treatment of the underlying crystal structure is therefore crucial for
a correct description of the observed metal-insulator transition. Our
theoretical results are consistent with recent experimental observations, and
demonstrate that metallic behavior in heterostructures of otherwise insulating
materials can emerge also from mechanisms other than genuine interface effects.


title:
Evidence of a discontinuous disk structure around the Herbig Ae star HD
  139 614

abstract:
  A new class of pre-main sequence objects has been recently identified as
pre-transitional disks. They present near-infrared excess coupled to a flux
deficit at about 10 microns and a rising mid-infrared and far-infrared
spectrum. These features suggest a disk structure with inner and outer dust
components, separated by a dust-depleted region (or gap). We here report on the
first interferometric observations of the disk around the Herbig Ae star HD
139614. Its infrared spectrum suggests a flared disk, and presents
pre-transitional features,namely a substantial near-infrared excess accompanied
by a dip around 6 microns and a rising mid-infrared part. In this framework, we
performed a study of the spectral energy distribution (SED) and the
mid-infrared VLTI/MIDI interferometric data to constrain thespatial structure
of the inner dust disk region and assess its possibly multi-component
structure. We based our work on a temperature-gradient disk model that includes
dust opacity. While we could not reproduce the SED and interferometric
visibilities with a one-component disk, a better agreement was obtained with a
two-component disk model composed of an optically thin inner disk extending
from 0.22 to 2.3 au, a gap, and an outer temperature-gradient disk starting at
5.6 au. Therefore, our modeling favors an extended and optically thin inner
dust component and in principle rules out the possibility that the
near-infrared excess originates only from a spatially confined region.
Moreover, the outer disk is characterized by a very steep temperature profile
and a temperature higher than 300 K at its inner edge. This suggests the
existence of a warm component corresponding to a scenario where the inner edge
of the outer disk is directly illuminated by the central star. This is an
expected consequence of the presence of a gap, thus indicative of a
pre-transitional structure.


title: Searching for a lighter Higgs: parametrisation and sample tests

abstract:
  The structure of the Higgs sector is a major issue in the quest of a detailed
description of the electroweak interactions. Most of the effort is devoted to
the study of the standard model--like Higgs boson at 126 GeV, however the
experimental collaborations at the LHC are also searching for extra scalar
particles whose presence may hint to an extended Higgs sector, typical of many
extensions of the standard model. We study a model independent parametrisation
of a scalar particle lighter than the 126 GeV Higgs boson, which may be easily
implemented in the ongoing searches by ATLAS and CMS. Indeed many effective
Lagrangians/parametrisations used at present for the description of the Higgs
sector implicitly assume that no light particles other than the standard model
ones are present in the spectrum. We therefore introduce a parametrisation of a
two scalars model, one corresponding to the 126 GeV Higgs boson and the other
to a lighter scalar. After the introduction of such a tool, we consider two
typical examples falling in this category, in order to illustrate the use of
our formalism: the two Higgs doublet model and the next to minimal
supersymmetric standard model. Our results agree with the specific studies
performed for these models. Furthermore, employing such a generic
parametrisation allows us to translate the bounds to any model beyond the
standard model falling into this class.


title: Android Based Emergency Alert Button

abstract:
  Android is a java based operating system which runs on the Linux kernel. It
is lightweight and full featured. Android applications are developed using Java
and can be ported to new platform easily thereby fostering huge number of
useful mobile applications. This paper describes about a SOS application being
developed and its successful implementation with tested results. The
application has target users those sections of the people who surprisingly
falls into a situation where instant communication of their whereabouts becomes
indispensable to be informed to certain authorized persons at remote end


title: Intercomparison of General Circulation Models for Hot Extrasolar Planets

abstract:
  We compare five general circulation models (GCMs) which have been recently
used to study hot extrasolar planet atmospheres (BOB, CAM, IGCM, MITgcm, and
PEQMOD), under three test cases useful for assessing model convergence and
accuracy. Such a broad, detailed intercomparison has not been performed thus
far for extrasolar planets study. The models considered all solve the
traditional primitive equations, but employ different numerical algorithms or
grids (e.g., pseudospectral and finite volume, with the latter separately in
longitude-latitude and `cubed-sphere' grids). The test cases are chosen to
cleanly address specific aspects of the behaviors typically reported in hot
extrasolar planet simulations: 1) steady-state, 2) nonlinearly evolving
baroclinic wave, and 3) response to fast timescale thermal relaxation. When
initialized with a steady jet, all models maintain the steadiness, as they
should -- except MITgcm in cubed-sphere grid. A very good agreement is obtained
for a baroclinic wave evolving from an initial instability in pseudospectral
models (only). However, exact numerical convergence is still not achieved
across the pseudospectral models: amplitudes and phases are observably
different. When subject to a typical `hot-Jupiter'-like forcing, all five
models show quantitatively different behavior -- although qualitatively
similar, time-variable, quadrupole-dominated flows are produced. Hence, as have
been advocated in several past studies, specific quantitative predictions (such
as the location of large vortices and hot regions) by GCMs should be viewed
with caution. Overall, in the tests considered here, pseudospectral models in
pressure coordinate (PEBOB and PEQMOD) perform the best and MITgcm in
cubed-sphere grid performs the worst.


title: Boolean Lifting Property for Residuated Lattices

abstract:
  In this paper we define the Boolean Lifting Property (BLP) for residuated
lattices to be the property that all Boolean elements can be lifted modulo
every filter, and study residuated lattices with BLP. Boolean algebras, chains,
local and hyperarchimedean residuated lattices have BLP. BLP behaves
interestingly in direct products and involutive residuated lattices, and it is
closely related to arithmetic properties involving Boolean elements, nilpotent
elements and elements of the radical. When BLP is present, strong
representation theorems for semilocal and maximal residuated lattices hold.


title:
Influence of the surface band structure on electron emission spectra
  from metal surfaces

abstract:
  Electron distributions produced by grazing impact of fast protons on
Mg(0001), Cu(111), Ag(111) and Au(111) surfaces are investigated, focusing on
the effects of the electronic band structure. The process is described within
the Band-Structure-Based approximation, which is a perturbative method that
includes an accurate representation of the electron-surface interaction,
incorporating information of the electronic band structure of the solid. For
all the studied surfaces, the presence of partially occupied surface electronic
states produces noticeable structures in double differential - energy- and
angle- resolved - electron emission probabilities from the valence band. These
structures remain visible in electron emission spectra after adding
contributions coming from core electrons, which might make it possible their
experimental detection.


title:
Facile residue analysis of recent and prehistoric cook-stones using
  handheld Raman spectrometry

abstract:
  We performed food residue analysis of cook-stones from experimental and
prehistoric earth ovens using a handheld Raman spectrometry. Progress in modern
optical technology provides a facile means of rapid non-destructive
identification of residue artifacts from archaeological sites. For this study
spectral signatures were obtained on sotol (Dasylirion spp.) experimentally
baked in an earth oven as well as sotol residue on an experimentally used
processing tool. Inulin was the major residue component. The portable handheld
Raman spectrometer also detected traces of inulin on boiling stones used to
boil commercially obtained inulin. The Raman spectra of inulin and sotol may be
useful as signatures of wild plant residues in archaeology. Spectroscopic
analysis of millennia-old cook-stones from prehistoric archaeological sites in
Fort Hood, TX revealed the presence of residues whose further identification
requires improvement of current optical methods.


title: Interface motion in random media

abstract:
  We study the pinning phase transition for discrete surface dynamics in random
environments. A renormalization procedure is devised to prove that the
interface moves with positive velocity under a finite size condition. This
condition is then checked for different examples of microscopic dynamics to
illustrate the flexibility of the method. We show in our examples the existence
of a phase transition for various models, including high dimensional
interfaces, dependent environments and environments with arbitrarily deep
obstacles. Finally, our ballisticity criterion is proved to be valid up to the
critical threshold for a Lipschitz interface model.


title: Uniform self-diffusion in a granular gas

abstract:
  A granular gas composed of inelastic hard spheres or disks in the homogeneous
cooling state is considered. Some of the particles are labeled and their number
density exhibits a time-independent linear profile along a given direction. As
a consequence, there is a uniform flux of labeled particles in that direction.
It is shown that the inelastic Boltzmann-Enskog kinetic equation has a solution
describing this self-diffusion state. Approximate expressions for the transport
equation and the distribution function of labeled particles are derived. The
theoretical predictions are compared with simulation results obtained using the
direct Monte Carlo method to generate solutions of the kinetic equation. A
fairly good agreement is found.


title: Random regular graphs and the systole of a random surface

abstract:
  We study the systole of a random surface, where by a random surface we mean a
surface constructed by randomly gluing together an even number of triangles. We
study two types of metrics on these surfaces, the first one coming from using
ideal hyperbolic triangles and the second one using triangles that carry a
given Riemannian metric.
  In the hyperbolic case we compute the limit of the expected value of the
systole when the number of triangles goes to infinity (approximately 2.484). We
also determine the asymptotic probability distribution of the number of curves
of any finite length. This turns out to be a Poisson distribution.
  In the Riemannian case we give an upper bound to the limit supremum and a
lower bound to the limit infimum of the expected value of the systole depending
only on the metric on the triangle. We also show that this upper bound is sharp
in the sense that there is a sequence of metrics for which the limit infimum
comes arbitrarily close to the upper bound.
  The main tool we use is random regular graphs. One of the difficulties in the
proof of the limits is controlling the probability that short closed curves are
separating. To do this we first prove that the probability that a random cubic
graph has a short separating circuit tends to 0 for the number of vertices
going to infinity and show that this holds for circuits of a length up to
$\log_2$ of the number of vertices.


title: A weak version of the Lipman-Zariski conjecture

abstract:
  Let $X$ be a normal complex space such that the tangent sheaf $T_X$ is
locally free and locally admits a basis consisting of pairwise commuting vector
fields. Then $X$ is smooth.


title: Automorphic Galois representations and the inverse Galois problem

abstract:
  A strategy to address the inverse Galois problem over Q consists of
exploiting the knowledge of Galois representations attached to certain
automorphic forms. More precisely, if such forms are carefully chosen, they
provide compatible systems of Galois representations satisfying some desired
properties, e.g. properties that reflect on the image of the members of the
system. In this article we survey some results obtained using this strategy.


title: Resilient Control under Denial-of-Service

abstract:
  We investigate resilient control strategies for linear systems under
Denial-of-Service (DoS) attacks. By DoS attacks we mean interruptions of
communication on measurement (sensor-to-controller) and/or control
(controller-to-actuator) channels carried out by an intelligent adversary. We
characterize the duration of these interruptions under which stability of the
closed-loop system is preserved. The resilient nature of the control descends
from its ability to adapt the sampling rate to the occurrence of the DoS.


title:
Distributed Voltage and Current Control of Multi-Terminal High-Voltage
  Direct Current Transmission Systems

abstract:
  High-voltage direct current (HVDC) is a commonly used technology for
long-distance power transmission, due to its low resistive losses and low
costs. In this paper, a novel distributed controller for multi-terminal HVDC
(MTDC) systems is proposed. Under certain conditions on the controller gains,
it is shown to stabilize the MTDC system. The controller is shown to always
keep the voltages close to the nominal voltage, while assuring that the
injected power is shared fairly among the converters. The theoretical results
are validated by simulations, where the affect of communication time-delays is
also studied.


title:
A signature of chemical separation in the cooling curves of transiently
  accreting neutron stars

abstract:
  We show that convection driven by chemical separation can significantly
affect the cooling curves of accreting neutron stars after they go into
quiescence. We calculate the thermal relaxation of the neutron star ocean and
crust including the thermal and compositional fluxes due to convection. After
the inward propagating cooling wave reaches the base of the neutron star ocean,
the ocean begins to freeze, driving chemical separation. The resulting
convection transports heat inward, giving much faster cooling of the surface
layers than found assuming the ocean cools passively. The light curves
including convection show a rapid drop in temperature weeks after outburst.
Identifying this signature in observed cooling curves would constrain the
temperature and composition of the ocean as well as offer a real time probe of
the freezing of a classical multicomponent plasma.


title:
Observation of a Strong Atom-Dimer Attraction in a Mass-Imbalanced
  Fermi-Fermi Mixture

abstract:
  We investigate a mixture of ultracold fermionic $^{40}$K atoms and weakly
bound $^{6}$Li$^{40}$K dimers on the repulsive side of a heteronuclear atomic
Feshbach resonance. By radio-frequency spectroscopy we demonstrate that the
normally repulsive atom-dimer interaction is turned into a strong attraction.
The phenomenon can be understood as a three-body effect in which two heavy
$^{40}$K fermions exchange the light $^{6}$Li atom, leading to attraction in
odd partial-wave channels (mainly p-wave). Our observations show that mass
imbalance in a fermionic system can profoundly change the character of
interactions as compared to the well-established mass-balanced case.


title: Robust Rydberg interaction gates with adiabatic passage

abstract:
  We show that with adiabatic passage, one can reliably drive two-photon
optical transitions between the ground states and interacting Rydberg states in
a pair of atoms. For finite Rydberg interaction strengths a new adiabatic
pathway towards the doubly Rydberg excited state is identified when a constant
detuning is applied with respect to an intermediate optically excited level.
The Rydberg interaction among the excited atoms provides a phase that may be
used to implement quantum gate operations on atomic ground state qubits.


title: Calibration of the SST Image Scale Through the Use of Imaging Techniques

abstract:
  The Swedish 1-m Solar Telescope (SST) offers excellent imaging quality, but
it has a comparatively small field of view. This means that while observing the
solar photosphere, there has been no convenient way of calibrating the image
scale of the telescope. Other telescopes, such as NASA's Solar Dynamics
Observatory (SDO)utilize their larger Field of View (FOV) to use the solar disk
as a reference in order to measure the image scale. In the past, the image
scale of the SST has been determined by measuring the distance between the
moons of Jupiter in a captured SST image and comparing it to reference values,
as well as with the Venus transit of 2004. Both of these methods have their
drawbacks, including needing to open the telescope at night or waiting for the
very rare occurrence of a solar transit, which the telescope may not even be in
a position to observe. Additionally, assessing the accuracy of these methods
can be difficult. The purpose of this thesis is to examine the feasibility of
an idea proposed by the faculty of the Institute for Solar Physics at Stockholm
University, that would allow us to routinely calibrate the image scale of the
SST when desired and with known accuracy of the measurement, without the need
to open the telescope at night. The measurements performed so far are
consistent with the old value to about one third of a percent, with a total
uncertainty of the SST/CRISP image scale of about 0.1 percent. Resulting in a
grid spacing of the pinhole array of 5.15 arcseconds, which can be used to
determine the image scale of all the remaining science cameras of the SST.


title: Angular Dependence of Coherent Pion Production by Neutrinos

abstract:
  Coherent pion production by neutrinos has been interpreted in the framework
of the Partially Conserved Axial Current hypothesis (PCAC) and explicit model
calculations are available. In this article we compute angular correlations for
the produced pions which may help to separate the signal from the background.
We present many figures useful for the experiments and compare them with
another model.


title: Negative Improvements, Relative Validity and Elusive Goodness

abstract:
  Various issues related to the complexity of apprais- ing the capabilities of
physics models implemented in Monte Carlo simulation codes and the evolution of
the functional quality the associated software are considered, such as the
dependence on the experimental environment where the software operates and its
sensitivity to detector characteristics. The concept of software validity as
relative to the environment is illustrated by means of a real-life experimental
test case. Methods and techniques to mitigate the risk of deteriorating the
quality of the software are critically discussed: they concern various
disciplines of the software development process. Quantitative validation of
physics models is advocated as a method to appraise their capabilities
objectively and to monitor the evolution of their associated software behavior.


title: Data analysis with R in an experimental physics environment

abstract:
  A software package has been developed to bridge the R analysis model with the
conceptual analysis environment typical of radiation physics experiments. The
new package has been used in the context of a project for the validation of
simulation models, where it has demonstrated its capability to satisfy typical
requirements pertinent to the problem domain.


title: On Certain Lagrangian Submanifolds of $S^2\times S^2$ and $C P^n$

abstract:
  We consider various constructions of monotone Lagrangian submanifolds of $C
P^n, S^2\times S^2$, and quadric hypersurfaces of $C P^n$. In $S^2\times S^2$
and $C P^2$ we show that several different known constructions of exotic
monotone tori yield results that are Hamiltonian isotopic to each other, in
particular answering a question of Wu by showing that the monotone fiber of a
toric degeneration model of $C P^2$ is Hamiltonian isotopic to the Chekanov
torus. Generalizing our constructions to higher dimensions leads us to consider
monotone Lagrangian submanifolds (typically not tori) of quadrics and of $C
P^n$ which can be understood either in terms of the geodesic flow on $T^*S^n$
or in terms of the Biran circle bundle construction. Unlike previously-known
monotone Lagrangian submanifolds of closed simply connected symplectic
manifolds, many of our higher-dimensional Lagrangian submanifolds are provably
displaceable.


title: Physics Methods for the Simulation of Photoionisation

abstract:
  Several physics methods for the simulation of the photoelectric effect are
quantitatively evaluated with respect to a large collection of experimental
data retrieved from the literature. They include theoretical and empirical
calculations of total and partial cross sections, and calculations of the
photoelectron angular distribution. Some of these models are currently
implemented in general purpose Monte Carlo systems; some have been implemented
and evaluated for possible use in Monte Carlo particle transport for the first
time in this study.


title: Interacting quark matter equation of state for compact stars

abstract:
  Lattice QCD studies of the thermodynamics of the hot quark-gluon plasma (QGP)
demonstrate the importance of accounting for the interactions of quarks and
gluons, if one wants to investigate the phase structure of strongly interacting
matter. Motivated by this observation and using state-of-the-art results from
perturbative QCD, we construct a simple effective equation of state for cold
quark matter that consistently incorporates the effects of interactions and
furthermore includes a built-in estimate of the inherent systematic
uncertainties. This goes beyond the MIT bag model description in a crucial way,
yet leads to an equation of state that is equally straightforward to use.


title: Validation of Geant4 Electron Pair Production by Photons

abstract:
  The first results of a project in progress for the validation of the
simulation of electron-positron pair production are presented. They concern the
pair production cross section in a low energy range close to the production
threshold. The results hint to effects due to the granularity of tabulated
cross sections.


title: Remarks on double Higgs boson production by gluon fusion at threshold

abstract:
  The amplitude of double Higgs boson production by the gluon fusion, $gg \to
hh$, is known to be small due to cancellation between the graphs with the boson
trilinear coupling and those with the coupling to the top quark. For this
reason a study of this process was suggested as a sensitive probe of the Higgs
sector nonlinearity. We calculate in a closed analytical form this amplitude at
the threshold of the two bosons, where the cancellation is the strongest, and
discuss the origin of the small value of the amplitude. We also note that the
cancellation in the double boson production is in fact a part of a more general
phenomenon of suppression of similar threshold amplitudes for multiple boson
production, which, although not directly relevant to the actual top quark and
the Higgs boson, can be useful in other studies.


title: A simple holographic model of momentum relaxation

abstract:
  We consider a holographic model consisting of Einstein-Maxwell theory in
(d+1) bulk spacetime dimensions with (d-1) massless scalar fields. Momentum
relaxation is realised simply through spatially dependent sources for operators
dual to the neutral scalars, which can be engineered so that the bulk stress
tensor and resulting black brane geometry are homogeneous and isotropic. We
analytically calculate the DC conductivity, which is finite. In the d=3 case,
both the black hole geometry and shear-mode current-current correlators are
those of a sector of massive gravity.


title:
Scholarly literature and the press: scientific impact and social
  perception of physics computing

abstract:
  The broad coverage of the search for the Higgs boson in the mainstream media
is a relative novelty for high energy physics (HEP) research, whose
achievements have traditionally been limited to scholarly literature. This
paper illustrates the results of a scientometric analysis of HEP computing in
scientific literature, institutional media and the press, and a comparative
overview of similar metrics concerning representative particle physics
measurements. The picture emerging from these scientometric data documents the
scientific impact and social perception of HEP computing. The results of this
analysis suggest that improved communication of the scientific and social role
of HEP computing would be beneficial to the high energy physics community.

categories: physics.soc-ph cs.DL hep-ex physics.comp-ph


title:
CME Expansion as the Driver of Metric Type II Shock Emission as Revealed
  by Self-Consistent Analysis of High Cadence EUV Images and Radio Spectrograms

abstract:
  On 13 June 2010, an eruptive event occurred near the solar limb. It included
a small filament eruption and the onset of a relatively narrow coronal mass
ejection (CME) surrounded by an extreme ultraviolet wave front recorded by the
Solar Dynamics Observatory's (SDO) Atmospheric Imaging Assembly (AIA) at high
cadence. The ejection was accompanied by a GOES M1.0 soft X-ray flare and a
Type-II radio burst; high-resolution dynamic spectra of the latter were
obtained by the ARTEMIS IV radio spectrograph. The combined observations
enabled a study of the evolution of the ejecta and the EUV wavefront and its
relationship with the coronal shock manifesting itself as metric Type-II burst.
By introducing a novel technique, which deduces a proxy of the EUV compression
ratio from AIA imaging data and compares it with the compression ratio deduced
from the band-split of the Type-II metric radio burst, we are able to infer the
potential source locations of the radio emission of the shock on that AIA
images. Our results indicate that the expansion of the CME ejecta is the source
for both EUV and radio shock emissions. Early in the CME expansion phase, the
Type-II burst seems to originate in the sheath region between the EUV bubble
and the EUV shock front in both radial and lateral directions. This suggests
that both the nose and the flanks of the expanding bubble could have driven the
shock.


title: Electron Correlation in Oxygen Vacancy in SrTiO$_3$

abstract:
  Oxygen vacancies are an important type of defect in transition metal oxides.
In SrTiO$_3$ they are believed to be the main donors in an otherwise intrinsic
crystal. At the same time, a relatively deep gap state associated with the
vacancy is widely reported. To explain this inconsistency we investigate the
effect of electron correlation in an oxygen vacancy (OV) in SrTiO$_3$. When
taking correlation into account, we find that the OV-induced localized level
can at most trap one electron, while the second electron occupies the
conduction band. Our results offer a natural explanation of how the OV in
SrTiO$_3$ can produce a deep in-gap level (about 1 eV below the conduction band
bottom) in photoemission, and at the same time be an electron donor. Our
analysis implies an OV in SrTiO$_3$ should be fundamentally regarded as a
magnetic impurity, whose deep level is always partially occupied due to the
strong Coulomb repulsion. An OV-based Anderson impurity model is derived, and
its implications are discussed.


title:
Long-Term Radio Timing Observations of the Transition Millisecond Pulsar
  PSR~J1023+0038

abstract:
  The radio millisecond pulsar PSR J1023+0038 exhibits complex timing and
eclipse behavior. Here we analyze four years' worth of radio monitoring
observations of this object. We obtain a long-term timing solution, albeit with
large residual timing errors as a result of apparent orbital period variations.
We also observe variable eclipses when the companion passes near our line of
sight, excess dispersion measure near the eclipses and at random orbital
phases, and short-term disappearances of signal at random orbital phases. We
interpret the eclipses as possibly due to material in the companion's
magnetosphere supported by magnetic pressure, and the orbital period variations
as possibly due to a gravitational quadrupole coupling mechanism. Both of these
mechanisms would be the result of magnetic activity in the companion, in
conflict with evolutionary models that predict it should be fully convective
and hence non-magnetic. We also use our timing data to test for orbital and
rotational modulation of the system's $\gamma$-ray emission, finding no
evidence for orbital modulation and $3.7\sigma$ evidence for modulation at the
pulsar period. The energetics of the system make it plausible that the
$\gamma$-ray emission we observe is entirely from the millisecond pulsar
itself, but it seems unlikely for these $\gamma$-rays to provide the
irradiation of the companion, which we attribute instead to X-ray heating from
a shock powered by a particle wind.


title: Algebraic proofs of some fundamental theorems in algebraic $K$-theory

abstract:
  We present news proofs of the additivity, resolution and cofinality theorems
for the algebraic $K$-theory of exact categories. These proofs are entirely
algebraic, based on Grayson's presentation of higher algebraic $K$-groups via
binary complexes.