title:
Dark-Matter Halo Profiles of a General Cusp/Core with Analytic Velocity
  and Potential

abstract:
  We present useful functions for the profiles of dark-matter (DM) haloes with
a free inner slope, from cusps to cores, where the profiles of density,
mass-velocity and potential are simple analytic expressions. Analytic velocity
is obtained by expressing the mean density as a simple functional form, and
deriving the local density by differentiation. The function involves four shape
parameters, with only two or three free: a concentration parameter $c$, inner
and outer asymptotic slopes $\alpha$ and $\bar{\gamma}$, and a middle shape
parameter $\beta$. Analytic expressions for the potential and velocity
dispersion exist for $\bar{\gamma}=3$ and for $\beta$ a natural number. We
match the models to the DM haloes in cosmological simulations, with and without
baryons, ranging from steep cusps to flat cores. Excellent fits are obtained
with three free parameters ($c$, $\alpha$, $\bar{\gamma}$) and $\beta=2$. For
an analytic potential, similar fits are obtained for $\bar{\gamma}=3$ and
$\beta=2$ with only two free parameters ($c$, $\alpha$); this is our favorite
model. A linear combination of two such profiles, with an additional free
concentration parameter, provides excellent fits also for $\beta=1$, where the
expressions are simpler. The fit quality is comparable to non-analytic popular
models. An analytic potential is useful for modeling the inner-halo evolution
due to gas inflows and outflows, studying environmental effects on the outer
halo, and generating halo potentials or initial conditions for simulations. The
analytic velocity can quantify simulated and observed rotation curves without
numerical integrations.


title: Kibble-Zurek mechanism in the self-organization of a cold atomic cloud

abstract:
  When applying two counter-propagating laser beams to a cold cloud of Rubidium
atoms, we observe the spontaneous formation of intensity patterns associated
with a spatial structuration of the atomic spins. We study the average number
of defects in these patterns as a function of the sweep time employed to cross
the transition threshold. We observe a power-law decrease of the number of
defects with increasing sweep time, typical of the Kibble-Zurek mechanism. The
measured exponent is consistent with the prediction for a supercritical
bifurcation.


title:
The properties of the Malin 1 galaxy giant disk: A panchromatic view
  from the NGVS and GUViCS surveys

abstract:
  Low surface brightness galaxies (LSBGs) represent a significant percentage of
local galaxies but their formation and evolution remain elusive. They may hold
crucial information for our understanding of many key issues (i.e., census of
baryonic and dark matter, star formation in the low density regime, mass
function). The most massive examples - the so called giant LSBGs - can be as
massive as the Milky Way, but with this mass being distributed in a much larger
disk. Malin 1 is an iconic giant LSBG, perhaps the largest disk galaxy known.
We attempt to bring new insights on its structure and evolution on the basis of
new images covering a wide range in wavelength. We have computed surface
brightness profiles (and average surface brightnesses in 16 regions of
interest), in six photometric bands (FUV, NUV, u, g, i, z). We compared these
data to various models, testing a variety of assumptions concerning the
formation and evolution of Malin 1. We find that the surface brightness and
color profiles can be reproduced by a long and quiet star-formation history due
to the low surface density; no significant event, such as a collision, is
necessary. Such quiet star formation across the giant disk is obtained in a
disk model calibrated for the Milky Way, but with an angular momentum
approximately 20 times larger. Signs of small variations of the star-formation
history are indicated by the diversity of ages found when different regions
within the galaxy are intercompared.For the first time, panchromatic images of
Malin 1 are used to constrain the stellar populations and the history of this
iconic example among giant LSBGs. Based on our model, the extreme disk of Malin
1 is found to have a long history of relatively low star formation (about 2
Msun/yr). Our model allows us to make predictions on its stellar mass and
metallicity.


title:
Equation of State for Nucleonic and Hyperonic Neutron Stars with Mass
  and Radius Constraints

abstract:
  We obtain a new equation of state for the nucleonic and hyperonic inner core
of neutron stars that fulfills the 2$M_{\odot}$ observations as well as the
recent determinations of stellar radii below 13 km. The nucleonic equation of
state is obtained from a new parametrization of the FSU2 relativistic
mean-field functional that satisfies these latest astrophysical constraints
and, at the same time, reproduces the properties of nuclear matter and finite
nuclei while fulfilling the restrictions on high-density matter deduced from
heavy-ion collisions. On the one hand, the equation of state of neutron star
matter is softened around saturation density, which increases the compactness
of canonical neutron stars leading to stellar radii below 13 km. On the other
hand, the equation of state is stiff enough at higher densities to fulfill the
2$M_{\odot}$ limit. By a slight modification of the parametrization, we also
find that the constraints of 2$M_{\odot}$ neutron stars with radii around 13 km
are satisfied when hyperons are considered. The inclusion of the high magnetic
fields present in magnetars further stiffens the equation of state. Hyperonic
magnetars with magnetic fields in the surface of $ \sim 10^{15}$ G and with
values of $\sim 10^{18}$ G in the interior can reach maximum masses of
2$M_{\odot}$ with radii in the 12-13 km range.


title: Gender Systematics in Telescope Time Allocation at ESO

abstract:
  The results of a comprehensive statistical analysis of gender systematics in
the time allocation process at European Southern Observatory (ESO) are
presented. The sample on which the study is based includes more than 13000
Normal and Short proposals, submitted by about 3000 principal investigators
(PI) over eight years. The genders of PIs, and of the panel members of the
Observing Programmes Committee (OPC), were used, together with their career
level, to analyse the grade distributions and the proposal success rates.
Proposals submitted by female PIs show a significantly lower probability of
being allocated time. The proposal success rates (defined as number of top
ranked runs over requested runs) are 16.0$\pm$0.6% and 22.0$\pm$0.4% for
females and males, respectively. To a significant extent the disparity is
related to different input distributions in terms of career level. The
seniority of male PIs is significantly higher than that of female PIs, with
only 34% of the female PIs being professionally employed astronomers (compared
to 53% for male PIs). A small, but statistically significant, gender-dependent
behaviour is measured for the OPC referees: both genders show the same
systematics, but they are larger for males than females. The PI female/male
fraction is very close to 30/70; although far from parity, the fraction is
higher than that observed, for instance, among IAU membership.


title:
A refinement of P\'olya's method to construct Voronoi diagrams for
  rational functions

abstract:
  Given a complex polynomial $P$ with zeroes $z_1,\dotsc,z_d$, we show that the
asymptotic zero-counting measure of the iterated derivatives $Q^{(n)}, \
n=1,2,\dotsc$, where $Q=R/P$ is any irreducible rational function, converges to
an explicitly constructed probability measure supported by the Voronoi diagram
associated with $z_1,\dotsc,z_d$. This refines P\'olya's Shire theorem for
these functions. In addition, we prove a similar result, using currents, for
Voronoi diagrams associated with generic hyperplane configurations in $\mathbb
C^m$.


title:
Generalised spheroidal spacetimes in 5-D
  Einstein--Maxwell--Gauss--Bonnet gravity

abstract:
  The field equations for static EGBM gravity are obtained and transformed to
an equivalent form through a coordinate redefinition. A form for one of the
metric potentials that generalises the spheroidal ansatz of Vaidya--Tikekar
superdense stars and additionally prescribing the electric field intensity
yields viable solutions. Some special cases of the general solution are
considered and analogous classes in the Einstein framework are studied. In
particular the Finch--Skea ansatz is examined in detail and found to satisfy
the elementary physical requirements. These include positivity of pressure and
density, the existence of a pressure free hypersurface marking the boundary,
continuity with the exterior metric, a subluminal sound speed as well as the
energy conditions. Moreover, the solution possesses no coordinate
singularities. It is found that the impact of the Gauss--Bonnet term is to
correct undesirable features in the pressure profile and sound speed index when
compared to the equivalent Einstein gravity model. Furthermore graphical
analyses suggest that higher densities are achievable for the same radial
values when compared to the 5--dimensional Einstein case. The case of a
constant gravitational potential, isothermal distribution as well as an
incompressible fluid are studied. All exact solutions derived exhibit an
equation of state explicitly.


title: A quantum subgroup depth

abstract:
  The Green ring of the half quantum group $H=U_n(q)$ is computed in [Chen, Van
Oystaeyen, Zhang]. The tensor product formulas between indecomposables may be
used for a generalized subgroup depth computation in the setting of quantum
groups -- to compute depth of the Hopf subalgebra $H$ in its Drinfeld double
$D(H)$. In this paper the Hopf subalgebra quotient module $Q$ (a generalization
of the permutation module of cosets for a group extension) is computed and, as
$H$-modules, $Q$ and its second tensor power are decomposed into a direct sum
of indecomposables. We note that the least power $n$, referred to as depth, for
which $Q^{\otimes (n)}$ has the same indecomposable constituents as $Q^{\otimes
(n+1)}$ is $n = 2$, since $ Q^{\otimes (2)}$ contains all $H$-module
indecomposables, which determines the minimum even depth $d_{ev}(H,D(H)) = 6$.


title:
Efficient creation of dipolar coupled nitrogen-vacancy spin qubits in
  diamond

abstract:
  Coherently coupled pairs or multimers of nitrogen-vacancy defect electron
spins in diamond have many promising applications especially in quantum
information processing (QIP) but also in nanoscale sensing applications.
Scalable registers of spin qubits are essential to the progress of QIP. Ion
implantation is the only known technique able to produce defect pairs close
enough to allow spin coupling via dipolar interaction. Although several
competing methods have been proposed to increase the resulting resolution of
ion implantation, the reliable creation of working registers is still to be
demonstrated. The current limitation are residual radiation-induced defects,
resulting in degraded qubit performance as trade-off for positioning accuracy.
Here we present an optimized estimation of nanomask implantation parameters
that are most likely to produce interacting qubits under standard conditions.
We apply our findings to a well-established technique, namely masks written in
electron-beam lithography, to create coupled defect pairs with a reasonable
probability. Furthermore, we investigate the scaling behavior and necessary
improvements to efficiently engineer interacting spin architectures.


title:
Direct measurement of low-energy $^{22}$Ne(p,$\gamma$)$^{23}$Na
  resonances

abstract:
  The $^{22}$Ne(p,$\gamma$)$^{23}$Na reaction is the most uncertain process in
the neon-sodium cycle of hydrogen burning. At temperatures relevant for
nucleosynthesis in asymptotic giant branch stars and classical novae, its
uncertainty is mainly due to a large number of predicted but hitherto
unobserved resonances at low energy. Purpose: A new direct study of low energy
$^{22}$Ne(p,$\gamma$)$^{23}$Na resonances has been performed at the Laboratory
for Underground Nuclear Astrophysics (LUNA), in the Gran Sasso National
Laboratory, Italy. Method: The proton capture on $^{22}$Ne was investigated in
direct kinematics, delivering an intense proton beam to a $^{22}$Ne gas target.
$\gamma$ rays were detected with two high-purity germanium detectors enclosed
in a copper and lead shielding suppressing environmental radioactivity.
Results: Three resonances at 156.2 keV ($\omega\gamma$ =
(1.48\,$\pm$\,0.10)\,$\cdot$\,10$^{-7}$ eV), 189.5 keV ($\omega\gamma$ =
(1.87\,$\pm$\,0.06)\,$\cdot$\,10$^{-6}$ eV) and 259.7 keV ($\omega\gamma$ =
(6.89\,$\pm$\,0.16)\,$\cdot$\,10$^{-6}$ eV) proton beam energy, respectively,
have been observed for the first time. For the levels at 8943.5, 8975.3, and
9042.4 keV excitation energy corresponding to the new resonances, the
$\gamma$-decay branching ratios have been precisely measured. Three additional,
tentative resonances at 71, 105 and 215 keV proton beam energy, respectively,
were not observed here. For the strengths of these resonances, experimental
upper limits have been derived that are significantly more stringent than the
upper limits reported in the literature. Conclusions: Based on the present
experimental data and also previous literature data, an updated thermonuclear
reaction rate is provided in tabular and parametric form. The new reaction rate
is significantly higher than previous evaluations at temperatures of 0.08-0.3
GK.


title: Primary decomposition and normality of certain determinantal ideals

abstract:
  In this paper we study primality and primary decomposition of certain ideals
which are generated by homogeneous degree $2$ polynomials and occur naturally
from determinantal conditions. Normality is derived from these results.


title:
The case of a generalised linear discrete time system with infinite many
  solutions

abstract:
  In this article we study a class of generalised linear systems of difference
equations with given non-consistent initial conditions and infinite many
solutions. We take into consideration the case that the coefficients are square
constant matrices with the leading coefficient singular. We provide optimal
solutions and numerical examples to justify our theory.


title:
Measuring the degeneracy of discrete energy levels using a GaAs/AlGaAs
  quantum dot

abstract:
  We demonstrate an experimental method for measuring quantum state
degeneracies in bound state energy spectra. The technique is based on the
general principle of detailed balance, and the ability to perform precise and
efficient measurements of energy-dependent tunnelling-in and -out rates from a
reservoir. The method is realized using a GaAs/AlGaAs quantum dot allowing for
the detection of time-resolved single-electron tunnelling with a precision
enhanced by a feedback-control. It is thoroughly tested by tuning orbital and
spin-degeneracies with electric and magnetic fields. The technique also lends
itself for studying the connection between the ground state degeneracy and the
lifetime of the excited states.


title:
Anisotropic type-I superconductivity and anomalous superfluid density in
  OsB 2

abstract:
  We present a microscopic study of superconductivity in OsB2 , and discuss the
origin and characteristic length scales of the superconducting state. From
first-principles we show that OsB2 is characterized by three different Fermi
sheets, and we prove that this fermiology complies with recent
quantum-oscillation experiments. Using the found microscopic properties, and
experimental data from the literature, we employ Ginzburg-Landau relations to
reveal that OsB2 is a distinctly type-I superconductor with very low
Ginzburg-Landau parameter kappa - a rare property among compound materials. We
show that the found coherence length and penetration depth corroborate the
measured thermodynamic critical field. Moreover, our calculation of the
superconducting gap structure using anisotropic Eliashberg theory and ab initio
calculated electron-phonon interaction as input reveals a single but
anisotropic gap. The calculated gap spectrum is shown to give an excellent
account for the unconventional behavior of the superfluid density of OsB2
measured in experiments as a function of temperature. This reveals that gap
anisotropy can explain such behavior, observed in several compounds, which was
previously attributed solely to a two-gap nature of superconductivity.


title:
Nuclear Numerical Range and Quantum Error Correction Codes for
  non-unitary noise models

abstract:
  We introduce a notion of nuclear numerical range defined as the set of
expectation values of a given operator $A$ among normalized pure states, which
belong to the nucleus of an auxiliary operator $Z$. This notion proves to be
applicable to investigate models of quantum noise with block-diagonal structure
of the corresponding Kraus operators. The problem of constructing a suitable
quantum error correction code for this model can be restated as a geometric
problem of finding intersection points of certain sets in the complex plane.
This technique, worked out in the case of two-qubit systems, can be generalized
for larger dimensions.


title: Effect of temperature on spin-transfer torque induced magnetic solitons

abstract:
  Spin-transfer torques in a nanocontact to an extended magnetic film can
create spin waves that condense to form dissipative droplet solitons. Here we
report an experimental study of the temperature dependence of the current and
applied field thresholds for droplet soliton formation, as well as the
nanocontact's electrical characteristics associated with droplet dynamics.
Nucleation of droplet solitons requires higher current densities at higher
temperatures, in contrast to typical spin-transfer torque induced switching
between static magnetic states. Magnetoresistance and electrical noise
measurements show that soliton instabilities become more pronounced with
increasing temperature. These results are of fundamental interest in
understanding the influence of thermal noise on droplet solitons, and in
controlling their dynamics.


title:
Leptonic decay-constant ratio $f_K/f_\pi$ from clover-improved $N_f=2+1$
  QCD

abstract:
  The leptonic decay-constant ratio $f_K/f_\pi$ is calculated from lattice-QCD
simulations using $N_f=2+1$ dynamical fermion flavors in the clover-improved
formulation and 2-HEX smearing. The simulations were performed for a range of
mass-degenerate light quarks including the physical point and at various
lattice couplings and volumes, allowing to quantify all relevant sources of
systematic uncertainties for our final number of the decay-constant ratio.
Utilizing input from chiral perturbation theory, we also quote the charged
decay-constant ratio $f_{K^\pm}/f_{\pi^\pm}$. With further input from
super-allowed nuclear $\beta$-decays, eventually we obtain an estimate for the
CKM-matrix element $V_{\rm us}$.


title:
A note on the Moser-Trudinger inequality in Sobolev-Slobodeckij spaces
  in dimension one

abstract:
  We discuss some recent results by Parini and Ruf on a Moser-Trudinger type
inequality in the setting of Sobolev-Slobodeckij spaces in dimension one. We
push further their analysis considering the inequality on the whole
$\mathbb{R}$ and we give an answer to one of their open questions.


title:
Critical behaviour of reduced QED$_{4,3}$ and dynamical fermion gap
  generation in graphene

abstract:
  The dynamical generation of a fermion gap in graphene is studied at the
infra-red Lorentz-invariant fixed point where the system is described by an
effective relativistic-like field theory: reduced QED$_{4,3}$ with $N$ four
component fermions ($N=2$ for graphene), where photons are $(3+1)$-dimensional
and mediate a fully retarded interaction among $(2+1)$-dimensional fermions. A
correspondence between reduced QED$_{4,3}$ and QED$_3$ allows us to derive an
exact gap equation for QED$_{4,3}$ up to next-to-leading order. Our results
show that a dynamical gap is generated for $\alpha > \alpha_c$ where $1.03 <
\alpha_c < 1.08$ in the case $N=2$ or for $N < N_c$ where $N_c$ is such that
$\alpha_c \to \infty$ and takes the values $3.24 < N_c < 3.36$. The striking
feature of these results is that they are in good agreement with values found
in models with instantaneous Coulomb interaction. At the fixed point: $\alpha =
1/137 \ll \alpha_c$, and the system is therefore in the semi-metallic regime in
accordance with experiments.


title: Symmetric and asymmetric Ramsey properties in random hypergraphs

abstract:
  A celebrated result of R\"odl and Ruci\'nski states that for every graph $F$,
which is not a forest of stars and paths of length $3$, and fixed number of
colours $r\ge 2$ there exist positive constants $c, C$ such that for $p \leq
cn^{-1/m_2(F)}$ the probability that every colouring of the edges of the random
graph $G(n,p)$ contains a monochromatic copy of $F$ is $o(1)$ (the
"0-statement"), while for $p \geq Cn^{-1/m_2(F)}$ it is $1-o(1)$ (the
"1-statement"). Here $m_2(F)$ denotes the $2$-density of $F$. On the other
hand, the case where $F$ is a forest of stars has a coarse threshold which is
determined by the appearance of a certain small subgraph in $G(n, p)$.
  Recently, the natural extension of the 1-statement of this theorem to
$k$-uniform hypergraphs was proved by Conlon and Gowers and, independently, by
Friedgut, R\"odl and Schacht. In particular, they showed an upper bound of
order $n^{-1/m_k(F)}$ for the $1$-statement, where $m_k(F)$ denotes the
$k$-density of $F$. Similarly as in the graph case, it is known that the
threshold for star-like hypergraphs is given by the appearance of small
subgraphs. In this paper we show that another type of thresholds exists if $k
\ge 4:$ there are $k$-uniform hypergraphs for which the threshold is determined
by the asymmetric Ramsey problem in which a different hypergraph has to be
avoided in each colour-class.
  Along the way we obtain a general bound on the $1$-statement for asymmetric
Ramsey properties in random hypergraphs. This extends the work of Kohayakawa
and Kreuter, and of Kohayakawa, Schacht and Sp\"ohel who showed a similar
result in the graph case. We prove the corresponding 0-statement for
hypergraphs satisfying certain balancedness conditions.


title: On decomposition of operators having $\Gamma_3$ as a spectral set

abstract:
  The symmetrized polydisc of dimension three is the set \[ \Gamma_3 =\{
(z_1+z_2+z_3, z_1z_2+z_2z_3+z_3z_1, z_1z_2z_3)\,:\, |z_i|\leq 1 \,,\, i=1,2,3
\} \subseteq \mathbb C^3\,. \] A triple of commuting operators for which
$\Gamma_3$ is a spectral set is called a $\Gamma_3$-contraction. We show that
every $\Gamma_3$-contraction admits a decomposition into a $\Gamma_3$-unitary
and a completely non-unitary $\Gamma_3$-contraction. This decomposition
parallels the canonical decomposition of a contraction into a unitary and a
completely non-unitary contraction. We also find new characterizations for the
set $\Gamma_3$ and $\Gamma_3$-contractions.


title: Sharpe portfolio using a cross-efficiency evaluation

abstract:
  The Sharpe ratio is a way to compare the excess returns (over the risk free
asset) of portfolios for each unit of volatility that is generated by a
portfolio. In this paper we introduce a robust Sharpe ratio portfolio under the
assumption that the risk free asset is unknown. We propose a robust portfolio
that maximizes the Sharpe ratio when the risk free asset is unknown, but is
within a given interval. To compute the best Sharpe ratio portfolio all the
Sharpe ratios for any risk free asset are considered and compared by using the
so-called cross-efficiency evaluation. An explicit expression of the
Cross-Eficiency Sharpe ratio portfolio is presented when short selling is
allowed.


title: Bouncing cosmologies with dark matter and dark energy

abstract:
  We review matter bounce scenarios where the matter content is dark matter and
dark energy. These cosmologies predict a nearly scale-invariant power spectrum
with a slightly red tilt for scalar perturbations and a small tensor-to-scalar
ratio. Importantly, these models predict a positive running of the scalar
index, contrary to the predictions of the simplest inflationary and ekpyrotic
models, and hence could potentially be falsified by future observations. We
also review how bouncing cosmological space-times can arise in theories where
either the Einstein equations are modified or where matter fields that violate
the null energy condition are included.


title: Equilibria of homogeneous functionals in the fair-competition regime

abstract:
  We consider macroscopic descriptions of particles where repulsion is modelled
by non-linear power-law diffusion and attraction by a homogeneous
singular/smooth kernel leading to variants of the Keller-Segel model of
chemotaxis. We analyse the regime in which both homogeneities scale the same
with respect to dilations, that we coin as fair-competition. In the singular
kernel case, we show that existence of global equilibria can only happen at a
certain critical value and they are characterised as optimisers of a variant of
HLS inequalities. We also study the existence of self-similar solutions for the
sub-critical case, or equivalently of optimisers of rescaled free energies.
These optimisers are shown to be compactly supported radially symmetric and
non-increasing stationary solutions of the non-linear Keller-Segel equation. On
the other hand, we show that no radially symmetric non-increasing stationary
solutions exist in the smooth kernel case, implying that there is no
criticality. However, we show the existence of positive self-similar solutions
for all values of the parameter under the condition that diffusion is not too
fast. We finally illustrate some of the open problems in the smooth kernel case
by numerical experiments.


title:
First-principles calculation method and its applications for
  two-dimensional materials

abstract:
  We present details of our effective computational methods based on the
real-space finite-difference formalism to elucidate electronic and magnetic
properties of the two-dimensional (2D) materials within the framework of the
density functional theory. The real-space finite-difference formalism enables
us to treat truly 2D computational models by imposing individual boundary
condition on each direction. The formulae for practical computations under the
boundary conditions specific to the 2D materials are derived and the electronic
band structures of 2D materials are demonstrated using the proposed method.
Additionally, we introduce other first-principles works on the MoS2 monolayer
focusing on the modulation of electronic and magnetic properties originating
from lattice defects.


title:
Bosonic Analogs of Fractional Quantum Hall State in the Vicinity of Mott
  States

abstract:
  In the present paper, the Bose-Hubbard model (BHM) with the nearest-neighbor
(NN) repulsions is studied from the view point of possible bosonic analogs of
the fractional quantum Hall (FQH) state in the vicinity of the Mott insulator
(MI). First, by means of the Gutzwiller approximation, we obtain the phase
diagram of the BHM in a magnetic field. Then, we introduce an effective
Hamiltonian describing excess particles on a MI and calculate the vortex
density, momentum distribution and the energy gap. These calculations indicate
that the vortex solid forms for small NN repulsions, but a homogeneous
featureless `Bose-metal' takes the place of it as the NN repulsion increases.
We consider particular filling factors at which the bosonic FQH state is
expected to form. Chern-Simons (CS) gauge theory to the excess particle is
introduced, and a modified Gutzwiller wave function, which describes bosons
with attached flux quanta, is introduced. The energy of the excess particles in
the bosonic FQH state is calculated using that wave function, and it is
compared with the energy of the vortex solid and Bose-metal. We found that the
energy of the bosonic FQH state is lower than that of the Bose-metal and
comparable with the vortex solid. Finally, we clarify the condition that the
composite fermion appears by using CS theory on the lattice that we previously
proposed for studying the electron FQH effect.


title:
Adaptive Molecular Resolution Approach in Hamiltonian Form: An
  Asymptotic Analysis

abstract:
  Adaptive Molecular Resolution approaches in Molecular Dynamics are becoming
relevant tools for the analysis of molecular liquids characterized by the
interplay of different physical scales. The essential difference among these
methods is in the way the change of molecular resolution is made in a
buffer/transition region. In particular a central question concerns the
possibility of the existence of a global Hamiltonian which, by describing the
change of resolution, is at the same time physically consistent, mathematically
well defined and numerically accurate. In this paper we present an asymptotic
analysis of the adaptive process complemented by numerical results and show
that under certain mathematical conditions a Hamiltonian, which is physically
consistent and numerically accurate, may exist. Such conditions show that
molecular simulations in the current computational implementation require
systems of large size and thus a Hamiltonian approach as the one proposed, at
this stage, would not be practical from the numerical point of view. However,
the Hamiltonian proposed provides the basis for a simplification and
generalization of the numerical implementation of adaptive resolution
algorithms to other molecular dynamics codes.


title:
Chains of topological oscillators with instantons and calculable
  topological observables in topological quantum mechanics

abstract:
  We extend to a possibly infinite chain the conformally invariant mechanical
system that was introduced earlier as a toy model for understanding the
topological Yang-Mills theory. It gives a topological quantum model that has
interesting and computable zero modes and topological invariants. It confirms
the recent conjecture by several authors that supersymmetric quantum mechanics
may provide useful tools for understanding robotic mechanical systems (Vitelli
et al.) and condensed matter properties (Kane et al.), where trajectories of
effective models are allowed or not by the conservation of topological indices.
The absences of ground state and mass gaps are special features of such
systems.


title: The Nature and Origin of Ultra-High Energy Cosmic Ray Particles

abstract:
  We outline two concepts to explain Ultra High Energy Cosmic Rays (UHECRs),
one based on radio galaxies and their relativistic jets and terminal hot spots,
and one based on relativistic Super-Novae (SNe) or Gamma Ray Bursts (GRBs) in
starburst galaxies, one matching the arrival direction data in the South (the
radio galaxy Cen A) and one in the North (the starburst galaxy M82). Ubiquitous
neutrino emission follows accompanied by compact TeV photon emission,
detectable more easily if the direction is towards Earth. The ejection of
UHECRs is last. We have observed particles up to ZeV, neutrinos up to PeV,
photons up to TeV, 30 - 300 Hz GW events, and hope to detect soon of order Hz
to mHz GW events. Energy turnover in single low frequency GW events may be of
order 10^63 erg. How can we further test these concepts? First of all by
associating individual UHECR events, or directional groups of events, with
chemical composition in both the Telescope Array (TA) Coll. and the Auger Coll.
data. Second by identifying more TeV to PeV neutrinos with recent SMBH mergers.
Third by detecting the order < mHz GW events of SMBH binaries, and identifying
the galaxies host to the stellar BH mergers and their GW events in the range up
to 300 Hz. Fourth by finally detecting the formation of the first generation of
SMBHs and their mergers, surely a spectacular discovery.


title:
Corrector estimates for a thermo-diffusion model with weak thermal
  coupling

abstract:
  The present work deals with the derivation of corrector estimates for the
two-scale homogenization of a thermo-diffusion model with weak thermal coupling
posed in a heterogeneous medium endowed with periodically arranged
high-contrast microstructures. The terminology "weak thermal coupling" refers
here to the variable scaling in terms of the small homogenization parameter of
the heat conduction-diffusion interaction terms, while the "high-contrast" is
thought particularly in terms of the heat conduction properties of the
composite material. As main target, we justify the first-order terms of the
multiscale asymptotic expansions in the presence of coupled fluxes, induced by
the joint contribution of Sorret and Dufour-like effects. The contrasting heat
conduction combined with cross coupling lead to the main mathematical
difficulty in the system. Our approach relies on the method of periodic
unfolding combined with a priori estimates for the thermal and concentration
fields and for their coupled fluxes.


title: Micro-Data Learning: The Other End of the Spectrum

abstract:
  Many fields are now snowed under with an avalanche of data, which raises
considerable challenges for computer scientists. Meanwhile, robotics (among
other fields) can often only use a few dozen data points because acquiring them
involves a process that is expensive or time-consuming. How can an algorithm
learn with only a few data points?


title: Gysin exact sequences for quantum weighted lens spaces

abstract:
  We describe quantum weighted lens spaces as total spaces of quantum principal
circle bundles, using a Cuntz-Pimsner model. The corresponding Pimsner exact
sequence is interpreted as a noncommutative analogue of the Gysin exact
sequence. We use the sequence to compute the K-theory and K-homology groups of
quantum weighted lens spaces, extending previous results and computations due
to the author and collaborators.


title:
Tomographic reflection modelling of quasi-periodic oscillations in the
  black hole binary H 1743-322

abstract:
  Accreting stellar mass black holes (BHs) routinely exhibit Type-C
quasi-periodic oscillations (QPOs). These are often interpreted as
Lense-Thirring precession of the inner accretion flow, a relativistic effect
whereby the spin of the BH distorts the surrounding space-time, inducing nodal
precession. The best evidence for the precession model is the recent discovery,
using a long joint XMM-Newton and NuSTAR observation of H 1743-322, that the
centroid energy of the iron fluorescence line changes systematically with QPO
phase. This was interpreted as the inner flow illuminating different azimuths
of the accretion disc as it precesses, giving rise to a blue/red shifted iron
line when the approaching/receding disc material is illuminated. Here, we
develop a physical model for this interpretation, including a self-consistent
reflection continuum, and fit this to the same H 1743-322 data. We use an
analytic function to parameterise the asymmetric illumination pattern on the
disc surface that would result from inner flow precession, and find that the
data are well described if two bright patches rotate about the disc surface.
This model is preferred to alternatives considering an oscillating disc
ionisation parameter, disc inner radius and radial emissivity profile. We find
that the reflection fraction varies with QPO phase (3.5 sigma), adding to the
now formidable body of evidence that Type-C QPOs are a geometric effect. This
is the first example of tomographic QPO modelling, initiating a powerful new
technique that utilizes QPOs in order to map the dynamics of accreting material
close to the BH.


title:
Scalar field with the source in the form of the stress-energy tensor
  trace as a dark energy model

abstract:
  We consider a scalar-tensor theory of gravitation with the scalar source
being the trace of the stress-energy tensor of the scalar field itself and
matter. We obtain an example of a numerical solution of the cosmological
equations which shows that under some special choice of the scalar parameters,
there exists a slow-roll regime in which the modern values of the Hubble and
deceleration parameters may be obtained.


title: Calculating the Tate local pairing for any odd prime number

abstract:
  Fisher and Newton have given an explicit description of the Tate local
pairing associated with the 3-torsion of an elliptic curve. The present paper
summarizes the work from the author's master's thesis and gives an explicit
formula for any odd prime $p$, thereby extending the work of Fisher and Newton.


title: Hybrid Regularisation of Functional Linear Models

abstract:
  We consider the problem of estimating the slope function in a functional
regression with a scalar response and a functional covariate. This central
problem of functional data analysis is well known to be ill-posed, thus
requiring a regularised estimation procedure. The two most commonly used
approaches are based on spectral truncation or Tikhonov regularisation of the
empirical covariance operator. In principle, Tikhonov regularisation is the
more canonical choice. Compared to spectral truncation, it is robust to
eigenvalue ties, while it attains the optimal minimax rate of convergence in
the mean squared sense, and not just in a concentration probability sense. In
this paper, we show that, surprisingly, one can strictly improve upon the
performance of the Tikhonov estimator in finite samples by means of a linear
estimator, while retaining its stability and asymptotic properties by combining
it with a form of spectral truncation. Specifically, we construct an estimator
that additively decomposes the functional covariate by projecting it onto two
orthogonal subspaces defined via functional PCA; it then applies Tikhonov
regularisation to the one component, while leaving the other component
unregularised. We prove that when the covariate is Gaussian, this hybrid
estimator uniformly improves upon the MSE of the Tikhonov estimator in a
non-asymptotic sense, effectively rendering it inadmissible. This domination is
shown to also persist under discrete observation of the covariate function. The
hybrid estimator is linear, straightforward to construct in practice, and with
no computational overhead relative to the standard regularisation methods. By
means of simulation, it is shown to furnish sizeable gains even for modest
sample sizes.


title: On colouring point visibility graphs

abstract:
  In this paper we show that it can be decided in polynomial time whether or
not the visibility graph of a given point set is 4-colourable, and such a
4-colouring, if it exists, can also be constructed in polynomial time. We show
that the problem of deciding whether the visibility graph of a point set is
5-colourable, is NP-complete. We give an example of a point visibility graph
that has chromatic number 6 while its clique number is only 4.


title:
Fast and Reliable Primary Frequency Reserves From Refrigerators with
  Decentralized Stochastic Control

abstract:
  Due to increasing shares of renewable energy sources, more frequency reserves
are required to maintain power system stability. In this paper, we present a
decentralized control scheme that allows a large aggregation of refrigerators
to provide Primary Frequency Control (PFC) reserves to the grid based on local
frequency measurements and without communication.
  The control is based on stochastic switching of refrigerators depending on
the frequency deviation. We develop methods to account for typical lockout
constraints of compressors and increased power consumption during the startup
phase. In addition, we propose a procedure to dynamically reset the thermostat
temperature limits in order to provide reliable PFC reserves, as well as a
corrective temperature feedback loop to build robustness to biased frequency
deviations. Furthermore, we introduce an additional randomization layer in the
controller to account for thermostat resolution limitations, and finally, we
modify the control design to account for refrigerator door openings.
  Extensive simulations with actual frequency signal data and with different
aggregation sizes, load characteristics, and control parameters, demonstrate
that the proposed controller outperforms a relevant state-of-the-art
controller.


title: Exact and Positive Controllability of Boundary Control Systems

abstract:
  Using the semigroup approach to abstract boundary control problems we
characterize the space of all exactly reachable states. Moreover, we study the
situation when the controls of the system are required to be positive. The
abstract results are applied to flows in networks with static as well as
dynamic boundary conditions.


title: Inventory growth cycles with debt-financed investment

abstract:
  We propose a continuous-time stock-flow consistent model for inventory
dynamics in an economy with firms, banks, and households. On the supply side,
firms decide on production based on adaptive expectations for sales demand and
a desired level of inventories. On the demand side, investment is determined as
a function of utilization and profitability and can be financed by debt,
whereas consumption is independently determined as a function of income and
wealth. Prices adjust sluggishly to both changes in labour costs and inventory.
Disequilibrium between expected sales and demand is absorbed by unplanned
changes in inventory. This results in a five-dimensional dynamical system for
wage share, employment rate, private debt ratio, expected sales, and capacity
utilization. We analyze two limiting cases: the long-run dynamics provides a
version of the Keen model with effective demand and varying inventories,
whereas the short-run dynamics gives rise to behaviour that we interpret as
Kitchin cycles.


title: Embracing data abundance: BookTest Dataset for Reading Comprehension

abstract:
  There is a practically unlimited amount of natural language data available.
Still, recent work in text comprehension has focused on datasets which are
small relative to current computing possibilities. This article is making a
case for the community to move to larger data and as a step in that direction
it is proposing the BookTest, a new dataset similar to the popular Children's
Book Test (CBT), however more than 60 times larger. We show that training on
the new data improves the accuracy of our Attention-Sum Reader model on the
original CBT test data by a much larger margin than many recent attempts to
improve the model architecture. On one version of the dataset our ensemble even
exceeds the human baseline provided by Facebook. We then show in our own human
study that there is still space for further improvement.


title:
Semileptonic decays of $\Lambda_c$ baryons in the relativistic quark
  model

abstract:
  Motivated by recent experimental progress in studying weak decays of the
$\Lambda_c$ baryon we investigate its semileptonic decays in the framework of
the relativistic quark model based on the quasipotential approach with the
QCD-motivated potential. The form factors of the $\Lambda_c\to \Lambda l\nu_l$
and $\Lambda_c\to nl\nu_l$ decays are calculated in the whole accessible
kinematical region without extrapolations and additional model assumptions.
Relativistic effects are systematically taken into account including
transformations of baryon wave functions from the rest to moving reference
frame and contributions of the intermediate negative-energy states. Baryon wave
functions found in the previous mass spectrum calculations are used for the
numerical evaluation. Comprehensive predictions for decay rates, asymmetries
and polarization parameters are given. They agree well with available
experimental data.


title: Microresonator Kerr frequency combs with high conversion efficiency

abstract:
  Microresonator-based Kerr frequency comb (microcomb) generation can
potentially revolutionize a variety of applications ranging from
telecommunications to optical frequency synthesis. However, phase-locked
microcombs have generally had low conversion efficiency limited to a few
percent. Here we report experimental results that achieve ~30% conversion
efficiency (~200 mW on-chip comb power excluding the pump) in the fiber
telecommunication band with broadband mode-locked dark-pulse combs. We present
a general analysis on the efficiency which is applicable to any phase-locked
microcomb state. The effective coupling condition for the pump as well as the
duty cycle of localized time-domain structures play a key role in determining
the conversion efficiency. Our observation of high efficiency comb states is
relevant for applications such as optical communications which require high
power per comb line.


title: Yet another p-adic hyperbolic disc

abstract:
  We describe in this paper a geometric construction in the projective p-adic
plane that gives, together with a suitable notion of p-adic convexity, some
open subsets of P 2 .Q p / naturally endowed with a "Hilbert" distance and a
transitive action of PGL.2; Q p / by isometries. ese open sets are natural
analogues of the hyperbolic disc, more precisely of Klein's projective model.
But, unlike the real case, there is not only one such hyperbolic disc. Indeed,
we nd three of them if p is odd (and seven if p D 2). Let us stress out that
neither the usual notion of convexity nor that of connectedness as known for
the real case are meaningful in the p-adic case. us, there will be a rephrasing
game for the denitions of real convexity until we reach a formulation suitable
for other local elds. It will lead us to a denition of p-adic convexity by
duality. Although we will not recover the beautiful behaviour of real
convexity, we will still be able to dene the most important tool for our goals,
namely the Hilbert distance. We construct our analogues of the hyperbolic disc
(once again, via the projective model of the hyperbolic plane) in a quite
geometric, even naive, way. Our construction gives 2-dimensional objects over Q
p. It is very dierent, in spirit and in facts, of Drinfeld p-adic hyperbolic
plane []. e possible relations between the two objects remain still unexplored.
Another object often viewed as an analogue of the hyperbolic disc is the tree
of PGL.2; Q p / []. We explore the relations between our discs and this tree,
constructing a natural quasi-isometric projection from the discs to the tree.
Eventually we explore the transformation groups of our discs. And, whereas the
transformation group of the tree is huge, we prove that only PGL.2; Q p / acts
on the discs preserving the convex structure.


title:
An Inexact Variable Metric Proximal Point Algorithm for Generic
  Quasi-Newton Acceleration

abstract:
  We propose an inexact variable-metric proximal point algorithm to accelerate
gradient-based optimization algorithms. The proposed scheme, called QNing can
be notably applied to incremental first-order methods such as the stochastic
variance-reduced gradient descent algorithm (SVRG) and other randomized
incremental optimization algorithms. QNing is also compatible with composite
objectives, meaning that it has the ability to provide exactly sparse solutions
when the objective involves a sparsity-inducing regularization. When combined
with limited-memory BFGS rules, QNing is particularly effective to solve
high-dimensional optimization problems, while enjoying a worst-case linear
convergence rate for strongly convex problems. We present experimental results
where QNing gives significant improvements over competing methods for training
machine learning methods on large samples and in high dimensions.


title:
Implement and commissioning of the beam energy feedback system in BEPCII
  linac

abstract:
  In order to ensure the beam quality and meet the requirements introduced by
the BEPCII storage ring, the beam energy feedback system has been developed at
the exit of the linac. This paper describes the implementation and
commissioning of this system in detail. The energy feedback system consists of
an energy measurement unit, an application software and an execution unit. In
order to ensure the real-time monitoring and adjustment of beam energy, we need
to introduce a non-interceptive type of online beam energy measurement method
which is on the first try in China and the effective mechanism of energy
adjustment to achieve this goal. The adjustment of energy is achieved by
adjusting the output microwave phase of the RF power source station. The system
was put into operation in March 16th, 2016 and achieved the desired results. It
can effectively eliminate the low point of the injection rate caused by the
fluctuation of the beam center energy and has played an important role in
maintaining a high constant injection rate.


title:
Application of beam deconvolution technique to power spectrum estimation
  for CMB measurements

abstract:
  We present two novel methods for the estimation of the angular power spectrum
of cosmic microwave background (CMB) anisotropies. We assume an absolute CMB
experiment with arbitrary asymmetric beams and arbitrary sky coverage. The
methods differ from earlier ones in that the power spectrum is estimated
directly from time-ordered data, without first compressing the data into a sky
map, and they take into account the effect of asymmetric beams. In particular,
they correct the beam-induced leakage from temperature to polarization. The
methods are applicable to a case where part of the sky has been masked out to
remove foreground contamination, leaving a pure CMB signal, but incomplete sky
coverage. The first method (DQML) is derived as the optimal quadratic
estimator, which simultaneously yields an unbiased spectrum estimate and
minimizes its variance. We successfully apply it to multipoles up to
$\ell$=200. The second method is derived as a weak-signal approximation from
the first one. It yields an unbiased estimate for the full multipole range, but
relaxes the requirement of minimal variance. We validate the methods with
simulations for the 70 GHz channel of {\tt Planck} surveyor, and demonstrate
that we are able to correct the beam effects in the $TT$, $EE$, $BB$, and $TE$
spectra up to multipole $\ell$=1500. Together the two methods cover the
complete multipole range with no gap in between.


title: A quantum cascade phonon-polariton laser

abstract:
  We report a laser that coherently emits phonon-polaritons, quasi-particles
arising from the coupling between photons and transverse optical phonons. The
gain is provided by an intersubband transition in a quantum cascade structure.
The polaritons at h$\nu$ = 45.4meV (corresponding to an emission frequency of
10.4THz) are formed by the transverse AlAs phonon mode of monolayer thin AlInAs
layers coupled to the optical modes of a Fabry-Perot cavity. The frequency
location of the laser mode is in good agreement with the computed polaritonic
dispersion and allows to quantify the constituent fractions of the emitted
polaritons that reach a maximum of 50% for the phonon fraction. A fraction of
the gain (between 2-5%) originates directly from the coupling between the
intersubband and the phonon polarizations. The device exhibits a very low
temperature dependence of its threshold current, as well as the capability to
operate in very thin ($\lambda/20$) optical cavities.


title:
A loop type component in the non-negative solutions set of an indefinite
  elliptic problem

abstract:
  We prove the existence of a loop type component of non-negative solutions for
an indefinite elliptic equation with homogeneous Neumann boundary conditions.
This result complements our previous results obtained in [12], where the
existence of another loop type component was established in a different
situation. Our proof combines local and global bifurcation theory, rescaling
and regularizing arguments, a priori bounds, and Whyburn's topological method.
A further investigation of the loop type component established in [12] is also
provided.


title: Character analogue of the Boole summation formula with applications

abstract:
  In this paper, we present the character analogue of the Boole summation
formula. Using this formula, an integral representation is derived for the
alternating Dirichlet $L-$function and its derivative is evaluated at $s=0$.
Some applications of the character analogue of the Boole summation formula and
the integral representation are given about the alternating Dirichlet
$L-$function. Moreover, the reciprocity formulas for two new arithmetic sums,
arising from utilizing the summation formulas, and for Hardy--Berndt sum
$S_{p}\left( b,c:\chi\right) $ are proved.


title:
Multiuser Detection in Multibeam Satellite Systems: Theoretical Analysis
  and Practical Schemes

abstract:
  We consider the rates achievable by a user in a multibeam satellite system
for unicast applications, and propose alternatives to the conventional
single-user symbol-by-symbol detection applied at user terminals. Single-user
detection is known to suffer from strong degradation when the terminal is
located near the edge of the coverage area of a beam, and when aggressive
frequency reuse is adopted. For this reason, we consider multiuser detection,
and take into account the strongest interfering signal. We also analyze two
additional transmission strategies requiring modifications at medium access
control layer. We describe an information-theoretic framework to compare the
different strategies by computing the information rate of the user in the
reference beam. Furthermore, we analyze the performance of coded schemes that
could approach the information-theoretic limits. We show that classical codes
from the DVB-S2(X) standard are not suitable when multiuser detection is
adopted, and we propose two ways to improve the performance, based on the
redesign of the code and of the bit mapping.


title: Device for measurement of thermal emissivity at cryogenic temperatures

abstract:
  In the described device, the thermal emissivity or absorptivity of the sample
is measured by substitution of the radiative heat flow between two parallel
surfaces by thermal output of a heater. Fast measurements of the mutual
emissivity for the range of the temperature of the radiating surface 25 K-150 K
are possible. The absorbing surface has a temperature between 5 K and 10 K when
LHe is used as cryoliquid. The desired measurement sensitivity is 1 mK for
temperature and 0.1 {\mu}W for heat power, respectively. The diameter of the
whole device is 50 mm and so it is possible to use a commercial dewar can for
the cooling. The form of the sample is a round plate 40 mm in diameter and 1 mm
in thickness with one tested side. The emissivity and its temperature
dependency for various surface treatments can be checked immediately before
application in a cryogenic system.


title: String field representation of the Virasoro algebra

abstract:
  We construct a representation of the zero central charge Virasoro algebra
using string fields in Witten's open bosonic string field theory. This
construction is used to explore extensions of the KBc algebra and find novel
algebraic solutions of open string field theory.


title:
Extracting band structure characteristics of GaSb/InAs core-shell
  nanowires from thermoelectric properties

abstract:
  Nanowires with a GaSb core and an InAs shell (and the inverted structure) are
interesting for studies of electron-hole hybridization and interaction effects
due to the bulk broken band-gap alignment at the material interface. We have
used eight-band $\mathbf{k\cdot p}$ theory together with the envelope function
approximation to calculate the band structure of such nanowires. For a fixed
core radius, as a function of shell thickness the band structure changes from
metallic (for a thick shell) to semiconducting (for a thin shell) with a gap
induced by quantum confinement. For intermediate shell thickness, a different
gapped band structure can appear, where the gap is induced by hybridization
between the valence band in GaSb and the conduction band in InAs. To establish
a relationship between the nanowire band structures and signatures in
thermoelectrical measurements, we use the calculated energy dispersions as
input to the Boltzmann equation and to ballistic transport equations to study
the diffusive limit and the ballistic limit, respectively. Our theoretical
results provide a guide for experiments, showing how thermoelectric
measurements in a gated setup can be used to distinguish between different
types of band gaps, or tune the system into a regime with few electrons and few
holes, which can be of interest for studies of exciton physics.


title:
Stochastic Optimization with Variance Reduction for Infinite Datasets
  with Finite-Sum Structure

abstract:
  Stochastic optimization algorithms with variance reduction have proven
successful for minimizing large finite sums of functions. Unfortunately, these
techniques are unable to deal with stochastic perturbations of input data,
induced for example by data augmentation. In such cases, the objective is no
longer a finite sum, and the main candidate for optimization is the stochastic
gradient descent method (SGD). In this paper, we introduce a variance reduction
approach for these settings when the objective is composite and strongly
convex. The convergence rate outperforms SGD with a typically much smaller
constant factor, which depends on the variance of gradient estimates only due
to perturbations on a single example.


title: Spectral determinants and an Ambarzumian type theorem on graphs

abstract:
  We consider an inverse problem for Schr\"odinger operators on connected
equilateral graphs with standard matching conditions. We calculate the spectral
determinant and prove that the asymptotic distribution of a subset of its zeros
can be described by the roots of a polynomial. We verify that one of the roots
is equal to the mean value of the potential and apply it to prove an
Ambarzumian type result, i.e., if a specific part of the spectrum is the same
as in the case of zero potential, then the potential has to be zero.


title: Investigation of Galactic open cluster remnants: the case of NGC 7193

abstract:
  Galactic open clusters (OCs) that survive the early gas-expulsion phase are
gradually destroyed over time by the action of disruptive dynamical processes.
Their final evolutionary stages are characterized by a poorly populated
concentration of stars called open cluster remnant (OCR). This study is devoted
to assess the real physical nature of the OCR candidate NGC 7193. GMOS/Gemini
spectroscopy of 53 stars in the inner target region were obtained to derive
radial velocities and atmospheric parameters. We also employed photometric and
proper motion data. The analysis method consists of the following steps: (i)
analysis of the statistical resemblance between the cluster and a set of field
samples with respect to the sequences defined in colour-magnitude diagrams
(CMDs); (ii) a 5-dimensional iteractive exclusion routine was employed to
identify outliers from kinematical and positional data; (iii) isochrone fitting
to the $K_{s}\times(J-K_{s})$ CMD of the remaining stars and the dispersion of
spectral types along empirical sequences in the $(J-H)\times(H-K_{s})$ diagram
was checked. A group of stars was identified for which the mean heliocentric
distance is compatible with that obtained via isochrone fitting and whose
metallicities are compatible with each other. Fifteen member stars observed
spectroscopically were identified together with other 19 probable members. Our
results indicate that NGC 7193 is a genuine OCR, of an once very populous OC,
for which the following parameters were derived: $d=501\,\pm\,46\,$pc,
$t=2.5\,\pm\,1.2\,$Gyr, $\langle\,[Fe/H]\,\rangle=-0.17\,\pm\,0.23$ and
$E(B-V)=0.05\,\pm\,0.05$. Its luminosity and mass functions show depletion of
low mass stars, confirming the OCR dynamically evolved state.


title:
A global existence result for the anisotropic magnetohydrodynamical
  systems

abstract:
  We study an anisotropic system arising in magnetohydrodynamics (MHD) in the
whole space R^3 , in the case where there are no diffusivity in the vertical
direction and only a small diffusivity in the horizontal direction (of size
$\epsilon$$\alpha$ with 0 \textless{} $\alpha$ $\le$ $\alpha$0, for some
$\alpha$0 \textgreater{} 0). We prove the local existence and uniqueness of a
strong solution and then, using Strichartz-type estimates, we prove that this
solution globally exists in time for large initial data, when the rotation is
fast enough.


title:
A New Approach for Helper Selection and Performance Analysis in Poisson
  CoopMAC Networks

abstract:
  The cooperative medium access control (CoopMAC) protocol in the presence of
randomly-distributed nodes and shadowing is considered. The nodes are assumed
to be distributed according to a homogeneous two-dimensional Poisson point
process. A new approach is proposed for helper selection and throughput
performance analysis which depends on the shadowing parameters as well as the
distribution of helpers. In the proposed protocol, the potential helpers are
divided into several tiers based on their distances from the source and
destination in a way that the lower the tier index, the higher its priority.
When there are several helpers of the same tier, the helper that is less
affected by shadowing is chosen for cooperation. Upper and lower bounds are
derived for the average cooperative throughput of the proposed CoopMAC
protocol. It is observed that the proposed scheme readily outperforms the
conventional CoopMAC protocol in having larger average throughput. It is also
seen that the cooperative throughput of the proposed scheme approaches the
upper bound when the density of nodes increases.


title: Wind Turbine Design: Multi-Objective Optimization

abstract:
  Within the last 20 years, wind turbines have reached matured and the growing
worldwide wind energy market will allow further improvements. In the recent
decades, the numbers of research papers that have applied optimization
techniques in the attempt to obtain an optimal design have increased. The main
target of manufacturers has been to minimize the cost of energy of wind
turbines in order to compete with fossil-fuel sources. Therefore, it has been
argued that it is more stimulating to evaluate the wind turbine design as an
optimization problem consisting of more than one objective. Using
multi-objective optimization algo- rithms, the designers are able to identify a
trade-off curve called Pareto front that reveals the weaknesses, anomalies and
rewards of certain targets. In this chapter, we present the fundamental
principles of multi-objective optimization in wind turbine design and solve a
classic multi-objective wind turbine optimization problem using a genetic
algorithm.


title:
A Constraint-Handling Technique for Genetic Algorithms using a Violation
  Factor

abstract:
  Over the years, several meta-heuristic algorithms were proposed and are now
emerging as common methods for constrained optimization problems. Among them,
genetic algorithms (GA's) shine as popular evolutionary algorithms (EA's) in
engineering optimization. Most engineering design problems are difficult to
resolve with conventional optimization algorithms because they are highly
nonlinear and contain constraints. In order to handle these constraints, the
most common technique is to apply penalty functions. The major drawback is that
they require tuning of parameters, which can be very challenging. In this
paper, we present a constraint-handling technique for GA's solely using the
violation factor, called VCH (Violation Constraint-Handling) method. Several
benchmark problems from the literature are examined. The VCH technique was able
to provide a consistent performance and match results from other GA-based
techniques.


title:
Preserving torsion orders when embedding into groups with `small' finite
  presentations

abstract:
  We give a complete survey of a construction by Boone and Collins for
embedding any finitely presented group into one with $8$ generators and $26$
relations. We show that this embedding preserves the set of orders of torsion
elements, and in particular torsion-freeness. We combine this with the
independent results of Belegradek and Chiodo to prove that there is an
$8$-generator $26$-relator universal finitely presented torsion-free group (one
into which all finitely presented torsion-free groups embed).


title: Neutrino Oscillation, Finite Self-Mass and General Yang-Mills Symmetry

abstract:
  The conservation of lepton number is assumed to be associated with a general
Yang-Mills symmetry. New transformations involve (Lorentz) vector gauge
functions and characteristic phase functions, and they form a group. General
Yang-Mills fields are associated with new fourth-order equations and linear
potentials. Lepton self-masses turn out to be finite and proportional to the
inverse of lepton masses, which implies that neutrinos should have non-zero
masses. Thus, general Yang-Mills symmetry could provide an understanding of
neutrino oscillations and suggests that neutrinos with masses and very weak
leptonic force may play a role in dark matter.


title:
Horizon Quantum Mechanics of Generalized Uncertainty Principle Black
  Holes

abstract:
  We study the Horizon Wavefunction (HWF) description of a generalized
uncertainty principle inspired metric that admits sub-Planckian black holes,
where the black hole mass $m$ is replaced by $M = m\left( 1 + \frac{\beta}{2}
\frac{M_{\rm Pl}^2}{m^2} \right)$. Considering the case of a wave-packet shaped
by a Gaussian distribution, we compute the HWF and the probability ${\cal
{P}}_{BH}$ that the source is a (quantum) black hole, i.e., that it lies within
its horizon radius. The case $\beta<0$ is qualitatively similar to the standard
Schwarzschild case, and the general shape of ${\cal {P}}_{BH}$ is maintained
when decreasing the free parameter, but shifted to reduce the probability for
the particle to be a black hole accordingly. The probability grows with
increasing mass slowly for more negative $\beta$, and drops to 0 for a minimum
mass value. The scenario differs in significantly for increasing $\beta>0$,
where a minimum in ${\cal {P}}_{BH}$ is encountered, thus meaning that every
particle has some probability of decaying to a black hole. Furthermore, for
sufficiently large $\beta$ we find that every particle is a quantum black hole,
in agreement with the intuitive effect of increasing $\beta$, which creates
larger $M$ and $R_{H}$ terms. This is likely due to a "dimensional reduction"
feature of the model, where the black hole characteristics for sub-Planckian
black holes mimic those in $(1+1)$-dimensions and the horizon size grows as
$R_H \sim M^{-1}$.


title: Concentration for Coulomb gases and Coulomb transport inequalities

abstract:
  We study the non-asymptotic behavior of Coulomb gases in dimension two and
more. Such gases are modeled by an exchangeable Boltzmann-Gibbs measure with a
singular two-body interaction. We obtain concentration of measure inequalities
for the empirical distribution of such gases around their equilibrium measure,
with respect to bounded Lipschitz and Wasserstein distances. This implies
macroscopic as well as mesoscopic convergence in such distances. In particular,
we improve the concentration inequalities known for the empirical spectral
distribution of Ginibre random matrices. Our approach is remarkably simple and
bypasses the use of renormalized energy. It crucially relies on new
inequalities between probability metrics, including Coulomb transport
inequalities which can be of independent interest. Our work is inspired by the
one of Ma{\"i}da and Maurel-Segala, itself inspired by large deviations
techniques. Our approach allows to recover, extend, and simplify previous
results by Rougerie and Serfaty.


title: Multifractal phenomena and packing dimension

abstract:
  We undertake a general study of multifractal phenomena for functions. We show
that the existence of several kinds of multifractal functions can be easily
deduced from an abstract statement, leading to new results. This general
approach does not work for Fourier or Dirichlet series. Using careful
constructions, we extend our results to these cases.


title:
Energy-Aware Wireless Relay Selection in Load-Coupled OFDMA Cellular
  Networks

abstract:
  We investigate transmission energy minimization via optimizing wireless relay
selection in orthogonal-frequency-division multiple access (OFDMA) networks. We
take into account the impact of the load of cells on transmission energy. We
prove the NP-hardness of the energy-aware wireless relay selection problem. To
tackle the computational complexity, a partial optimality condition is derived
for providing insights in respect of designing an effective and efficient
algorithm. Numerical results show that the resulting algorithm achieves high
energy performance.


title: Stochastic dynamics for adaptation and evolution of microorganisms

abstract:
  We present a model for the dynamics of a population of bacteria with a
continuum of traits, who compete for resources and exchange horizontally
(transfer) an otherwise vertically inherited trait with possible mutations.
Competition influences individual demographics, affecting population size,
which feeds back on the dynamics of transfer. We consider a stochastic
individual-based pure jump process taking values in the space of point
measures, and whose jump events describe the individual reproduction, transfer
and death mechanisms. In a large population scale, the stochastic process is
proved to converge to the solution of a nonlinear integro-differential
equation. When there are only two different traits and no mutation, this
equation reduces to a non-standard two-dimensional dynamical system. We show
how crucial the forms of the transfer rates are for the long-term behavior of
its solutions. We describe the dynamics of invasion and fixation when one of
the two traits is initially rare, and compute the invasion probabilities. Then,
we study the process under the assumption of rare mutations. We prove that the
stochastic process at the mutation time scale converges to a jump process which
describes the successive invasions of successful mutants. We show that the
horizontal transfer can have a major impact on the distribution of the
successive mutational fixations, leading to dramatically different behaviors,
from expected evolution scenarios to evolutionary suicide. Simulations are
given to illustrate these phenomena.


title:
On the State of Computing in Statistics Education: Tools for Learning
  and for Doing

abstract:
  This paper lays out the current landscape of tools used in statistics
education. In particular, it considers graphing calculators, spreadsheets,
applets and microworlds, standalone educational software, statistical
programming tools, tools for reproducible research and bespoke tools. The
strengths and weaknesses of the tools are considered, particularly in the
context of McNamara (2016)'s list of attributes for a statistical computing
tool. Best practices for computing in introductory statistics are suggested.


title: Key attributes of a modern statistical computing tool

abstract:
  In the 1990s, statisticians began thinking in a principled way about how
computation could better support the learning and doing of statistics. Since
then, the pace of software development has accelerated, advancements in
computing and data science have moved the goalposts, and it is time to
reassess. Software continues to be developed to help do and learn statistics,
but there is little critical evaluation of the resulting tools, and no accepted
framework with which to critique them. This paper presents a set of attributes
necessary for a modern statistical computing tool. The framework was designed
to be broadly applicable to both novice and expert users, with a particular
focus on making more supportive statistical computing environments. A modern
statistical computing tool should be accessible, provide easy entry, privilege
data as a first-order object, support exploratory and confirmatory analysis,
allow for flexible plot creation, support randomization, be interactive,
include inherent documentation, support narrative, publishing, and
reproducibility, and be flexible to extensions. Ideally, all these attributes
could be incorporated into one tool, supporting users at all levels, but a more
reasonable goal is for tools designed for novices and professionals to `reach
across the gap,' taking inspiration from each others' strengths.


title: The Montreal White Dwarf Database: a Tool for the Community

abstract:
  We present the "Montreal White Dwarf Database" (MWDD), an accessible database
with sortable/filterable table and interactive plots that will, when fully
completed, allow the community to explore the physical properties of all white
dwarfs ever analyzed by the Montreal group, as well as display data and
analyses from the literature. We present its current capability and show how it
will continuously be updated to instantly reflect improvements made on both the
theoretical and observational fronts.


title:
Control of the differential interference contrast in reinjected bimode
  laser

abstract:
  We have demonstrated, both theoretically and experimentally, that it is
possible to control (i.e., to enhance or cancel) the contrast of the
interference pattern appearing in the intensity images obtained with a laser
optical feedback imaging (LOFI) setup using a bimode laser. The laser is
composed of two coupled orthogonally polarized states that interact (i.e.,
interfere) through the cross saturation laser dynamics. We created the contrast
control by choosing the frequency shift (i.e., the beating frequency) between
the feedback electric fields and the intracavity electric fields. We have shown
that the interference contrast of the output power modulation of the laser
total intensity is independent from the frequency shift and is always maximal.
On the other hand, the interference contrast of each polarization state is
frequency dependent. We obtained the maximal contrast when the frequency shift
was equal to one of the resonance frequencies of the bimode dynamics, and was
very low (and almost cancels) for an intermediate frequency located at the
intersection of the two resonance curves.


title: Changing optical band structure with single photons

abstract:
  Achieving strong interactions between individual photons enables a wide
variety of exciting possibilities in quantum information science and many-body
physics. Cold atoms interfaced with nanophotonic structures have emerged as a
platform to realize novel forms of nonlinear interactions. In particular, when
atoms are coupled to a photonic crystal waveguide (PCW), long-range atomic
interactions can arise that are mediated by localized atom-photon bound states.
We theoretically show that in such a system, the absorption of a single photon
can change the band structure for a subsequent photon. This occurs because the
first photon affects the atoms in the chain in an alternating fashion, thus
leading to an effective period doubling of the system and a new optical band
structure for the composite atom-nanophotonic system. We demonstrate how this
mechanism can be engineered to realize a single-photon switch, where the first
incoming photon switches the system from being highly transmissive to highly
reflective, and analyze how signatures can be observed via non-classical
correlations of the outgoing photon field.


title: The Integrated Cluster Finder for the ARCHES project

abstract:
  Context. Clusters of galaxies are important for cosmology and astrophysics.
They may be discovered through either the summed optical/IR radiation
originating from their member galaxies or via X-ray emission originating from
the hot intracluster medium. X- ray samples are not affected by projection
effects but a redshift determination typically needs optical and infrared
follow-up to then infer X-ray temperatures and luminosities. Aims. We want to
confirm serendipitously discovered X-ray emitting cluster candidates and
measure their cosmological redshift through the analysis and exploration of
multi-wavelength photometric catalogues. Methods. We developed a tool, the
Integrated Cluster Finder (ICF), to search for clusters by determining
overdensities of potential member galaxies in optical and infrared catalogues.
Based on a spectroscopic meta-catalogue we calibrated colour-redshift relations
that combine optical (SDSS) and IR data (UKIDSS, WISE). The tool is used to
quantify the overdensity of galaxies against the background via a modified
redMaPPer technique and to quantify the confidence of a cluster detection.
Results. Cluster finding results are compared to reference catalogues found in
the literature. The results agree to within 95-98%. The tool is used to confirm
488 out of 830 cluster candidates drawn from 3XMMe in the footprint of the SDSS
and CFHT catalogues. Conclusions. The ICF is a flexible and highly efficient
tool to search for galaxy clusters in multiple catalogues and is freely
available to the community. It may be used to identify the cluster content in
future X-ray catalogues from XMM-Newton and eventually from eROSITA.


title: The solar-stellar connection: Magnetic activity of seismic solar analogs

abstract:
  Finding solar-analog stars with fundamental properties as close as possible
to the Sun and studying the characteristics of their surface magnetic activity
is a very promising way to understand the solar variability and its associated
dynamo process. However, the identification of solar-analog stars depends on
the accuracy of the estimated stellar parameters. Thanks to the photometric
CoROT and Kepler space missions, the addition of asteroseismic data was proven
to provide the most accurate fundamental properties that can be derived from
stellar modeling today. Here, we present our latest results on the
solar-stellar connection by studying 18 solar analogs that we identified among
the Kepler seismic sample (Salabert et al., 2016a). We measured their magnetic
activity properties using the observations collected by the Kepler satellite
and the ground-based, high-resolution HERMES spectrograph. The photospheric
(Sph) and chromospheric (S) magnetic activity proxies of these seismic solar
analogs are compared in relation to the solar activity. We show that the
activity of the Sun is comparable to the activity of the seismic solar analogs,
within the maximum-to-minimum temporal variations of the 11-year solar activity
cycle. Furthermore, we report on the discovery of temporal variability in the
acoustic frequencies of the young (1 Gyr-old) solar analog KIC10644253 with a
modulation of about 1.5 years, which agrees with the derived photospheric
activity Sph (Salabert et al, 2016b). It could be the signature of the
short-period modulation, or quasi-biennal oscillation, of its magnetic activity
as observed in the Sun and in the 1-Gyr-old solar analog HD30495. In addition,
the lithium abundance and the chromospheric activity estimated from HERMES
confirms that KIC10644253 is a young and more active star than the Sun.


title:
Improved recovery of admissible stress in domain decomposition methods -
  application to heterogeneous structures and new error bounds for FETI-DP

abstract:
  This paper investigates the question of the building of admissible stress
field in a substructured context. More precisely we analyze the special role
played by multiple points. This study leads to (1) an improved recovery of the
stress field, (2) an opportunity to minimize the estimator in the case of
heterogeneous structures (in the parallel and sequential case), (3) a procedure
to build admissible fields for FETI-DP and BDDC methods leading to an error
bound which separates the contributions of the solver and of the
discretization.


title: Existence of Minkowski space

abstract:
  Minkowski space serves as a framework for the theoretical constructions that
deal with manifestations of relativistic effects in physical phenomena. But
neither Minkowski himself nor the subsequent developers of the relativity
theory have provided a reasonable rationale for this mathematical construct. In
physics, such a rationale should show lower-level statements that determine
where the proposed mathematical structure is applicable and yield formal
premises for proving its existence.
  The above failure has apparently been due to the features of the adopted
formalism based on the unjustifiably exclusive use of coordinates in the
theoretical analysis of physical phenomena, which ignores the necessity of
having physical grounds for mathematical concepts. In particular, the use of a
coordinate transformation between two inertial reference frames makes the
consideration so cumbersome that it appears useless for solving the fundamental
problems of physical theory, including the question of whether Minkowski space
exists.
  In contrast, a straightforward calculation proves that the transformation of
the time and the position vector of a physical event between two physical
spaces establishes an equivalence relation between pairs made of these
variables. This means the existence of Minkowski space and shows that the
premises for its proof are the same as for the coordinate-free derivation of
basic effects of the special relativity theory: the use of Einsteinian time
variable and motions of particles able to interact with each other and
electromagnetic field over a short spatial range only.
  The high degeneracy of free motions of point particles, together with the
intricacy of the above mentioned calculation, suggests that a further
generalization of Minkowski space is beyond belief, so that the modification or
even the abandonment of the concept of spacetime seems quite natural.


title:
Consistency relations for large scale structures with primordial
  non-Gaussianities

abstract:
  We investigate how the consistency relations of large-scale structures are
modified when the initial density field is not Gaussian. We consider both
scenarios where the primordial density field can be written as a nonlinear
functional of a Gaussian field and more general scenarios where the probability
distribution of the primordial density field can be expanded around the
Gaussian distribution, up to all orders over $\delta_{L0}$. Working at linear
order over the non-Gaussianity parameters $f_{\rm NL}^{(n)}$ or $S_n$, we find
that the consistency relations for the matter density fields are modified as
they include additional contributions that involve all-order mixed
linear-nonlinear correlations $\langle \prod \delta_L \prod \delta \rangle$. We
derive the conditions needed to recover the simple Gaussian form of the
consistency relations. This corresponds to scenarios that become Gaussian in
the squeezed limit. Our results also apply to biased tracers, and velocity or
momentum cross-correlations.


title:
Combined 4-component and relativistic pseudopotential study of ThO for
  the electron electric dipole moment search

abstract:
  A precise theoretical study of the electronic structure of heavy atom
diatomic molecules is of key importance to interpret the experiments in the
search for violation of time-reversal (T) and spatial-parity (P) symmetries of
fundamental interactions it terms of the electron electric dipole moment, eEDM,
and dimensionless constant, $k_{T,P}$, characterizing the strength of the
T,P-odd pseudoscalar$-$scalar electron$-$nucleus neutral current interaction.
ACME collaboration has recently obtained and improved limits on these
quantities using a beam of ThO molecules in the $H^3\Delta_1$ state [Science
343, 269 (2014)]. We apply the combined direct 4-component and two-step
relativistic pseudopotential/restoration approaches to a benchmark calculation
of the effective electric field, Eeff, parameter of the T,P-odd
pseudoscalar$-$scalar interaction, $W_{T,P}$, and HFS constant in $^3\Delta_1$
state of the ThO molecule. The first two parameters are required to interpret
the experimental data in terms of the eEDM and $k_{T,P}$ constant. We have
investigated the electron correlation for all of the 98 electrons of ThO
simultaneously up to the level of the coupled cluster with single, double and
noniterative triple amplitudes theory. Contributions from iterative triple and
noniterative quadruple cluster amplitudes for the valence electrons have been
also treated. The obtained values are Eeff=79.9 GV/cm, $W_{T,P}$=113.1 kHz. The
theoretical uncertainty of these values we estimate as about two times smaller
than that of our previous study [JCP, 142, 024301 (2015)]. It was found that
the correlation of the inner- and outer- core electrons contributes 9% to the
effective electric field. The values of the molecule frame dipole moment of the
$^3\Delta_1$ state and the $H^3\Delta_1\to X^1\Sigma^+$ transition energy of
ThO calculated within the same methods are in a very good agreement with the
experiment.


title:
Designing a Broadband Pump for High-Quality Micro-Lasers via Modified
  Net Radiation Method

abstract:
  High-quality micro-lasers are key ingredients in non-linear optics,
communication, sensing and low-threshold solar-pumped lasers. However, such
micro-lasers exhibit negligible absorption of free-space broadband pump light.
Recently, this limitation was lifted by cascade energy transfer, in which the
absorption and quality factor are modulated with wavelength, enabling
non-resonant pumping of high-quality micro-lasers and solar-pumped laser to
operate at record low solar concentration. Here, we present a generic
theoretical framework for modeling the absorption, emission and energy transfer
of incoherent radiation between cascade sensitizer and laser gain media. Our
model is based on linear equations of the modified net radiation method and is
therefore robust, fast converging and has low complexity. We apply this
formalism to compute the optimal parameters of low-threshold solar-pumped
lasers. It is revealed that the interplay between the absorption and
self-absorption of such lasers defines the optimal pump absorption below the
maximal value, which is in contrast to conventional lasers for which full pump
absorption is desired. Numerical results are compared to experimental data on a
sensitized Nd:YAG cavity, and quantitative agreement with theoretical models is
found. Our work modularizes the gain and sensitizing components and paves the
way for the optimal design of broadband-pumped high-quality micro-lasers and
efficient solar-pumped lasers.


title:
Nucleation, instability, and discontinuous phase transitions in
  monoaxial helimagnets with oblique fields

abstract:
  The phase diagram of the monoaxial chiral helimagnet as a function of
temperature (T ) and magnetic field with components perpendicular (H x ) and
parallel (H z ) to the chiral axis is theoretically studied via the variational
mean field approach in the continuum limit. A phase transition surface in the
three dimensional thermodynamic space separates a chiral spatially modulated
phase from a homogeneous forced ferromagnetic phase. The phase boundary is
divided into three parts: two surfaces of second order transitions of
instability and nucleation type, in De Gennes terminology, are separated by a
surface of first order transitions. Two lines of tricritical points separate
the first order surface from the second order surfaces. The divergence of the
period of the modulated state on the nucleation transition surface has the
logarithmic behavior typical of a chiral soliton lattice. The specific heat
diverges on the nucleation surface as a power law with logarithmic corrections,
while it shows a finite discontinuity on the other two surfaces. The soliton
density curves are described by a universal function of H x if the values of T
and H z determine a transition point lying on the nucleation surface;
otherwise, they are not universal.


title:
Impact of embedding on predictability of failure-recovery dynamics in
  networks

abstract:
  Failure, damage spread and recovery crucially underlie many spatially
embedded networked systems ranging from transportation structures to the human
body. Here we study the interplay between spontaneous damage, induced failure
and recovery in both embedded and non-embedded networks. In our model the
network's components follow three realistic processes that capture these
features: (i) spontaneous failure of a component independent of the
neighborhood (internal failure), (ii) failure induced by failed neighboring
nodes (external failure) and (iii) spontaneous recovery of a component.We
identify a metastable domain in the global network phase diagram spanned by the
model's control parameters where dramatic hysteresis effects and random
switching between two coexisting states are observed. The loss of
predictability due to these effects depend on the characteristic link length of
the embedded system. For the Euclidean lattice in particular, hysteresis and
switching only occur in an extremely narrow region of the parameter space
compared to random networks. We develop a unifying theory which links the
dynamics of our model to contact processes. Our unifying framework may help to
better understand predictability and controllability in spatially embedded and
random networks where spontaneous recovery of components can mitigate
spontaneous failure and damage spread in the global network.


title:
Density matrix renormalization group (DMRG) for cyclic and
  centrosymmetric linear chains

abstract:
  The density matrix renormalization group (DMRG) method generates the
low-energy states of linear systems of $N$ sites with a few degrees of freedom
at each site by starting with a small system and adding sites step by step
while keeping constant the dimension of the truncated Hilbert space. DMRG
algorithms are adapted to open chains with inversion symmetry at the central
site, to cyclic chains and to weakly coupled chains. Physical properties rather
than energy accuracy is the motivation. The algorithms are applied to the edge
states of linear Heisenberg antiferromagnets with spin $S \ge 1$ and to the
quantum phases of a frustrated spin-1/2 chain with exchange between first and
second neighbors. The algorithms are found to be accurate for extended Hubbard
and related 1D models with charge and spin degrees of freedom.


title:
Exponential utility maximization under model uncertainty for unbounded
  endowments

abstract:
  We consider the robust exponential utility maximization problem in discrete
time: An investor maximizes the worst case expected exponential utility with
respect to a family of nondominated probabilistic models of her endowment by
dynamically investing in a financial market, and statically in available
options. We show that, for any measurable random endowment (regardless of
whether the problem is finite or not) an optimal strategy exists, a dual
representation in terms of (calibrated) martingale measures holds true, and
that the problem satisfies the dynamic programming principle (in case of no
options). Further it is shown that the value of the utility maximization
problem converges to the robust superhedging price as the risk aversion
parameter gets large, and examples of nondominated probabilistic models are
discussed.


title:
Statistical learning for wind power : a modeling and stability study
  towards forecasting

abstract:
  We focus on wind power modeling using machine learning techniques. We show on
real data provided by the wind energy company Ma{\"i}a Eolis, that parametric
models, even following closely the physical equation relating wind production
to wind speed are outperformed by intelligent learning algorithms. In
particular, the CART-Bagging algorithm gives very stable and promising results.
Besides, as a step towards forecast, we quantify the impact of using
deteriorated wind measures on the performances. We show also on this
application that the default methodology to select a subset of predictors
provided in the standard random forest package can be refined, especially when
there exists among the predictors one variable which has a major impact.


title:
The distribution and kinematics of interstellar O~{\small VI} in the
  Milky Way}

abstract:
  We present the results of a survey of interstellar O~{\small VI} absorption
in the Milky Way (MW) towards {69} stars in the Large Magellanic Cloud (LMC)
obtained with the \textit{Far Ultraviolet Spectroscopic Explorer (FUSE)}. The
integrated MW O~{\small VI} column densities log N(O~{\small VI}) are in the
range from 13.68 to 14.73 with a mean of {14.26$_{-0.09}^{+0.07}$} atoms
cm$^{-2}$. The O~{\small VI} exponential scale height is found to be
{2.28$\pm$1.06} kpc. The O~{\small VI} column density correlates with the
Doppler parameter $\it b$. The O~{\small VI} velocity dispersion ranges from
{14.0 to 91.6 with an average value of 62.7 km s$^{-1}$}. These high values of
velocity dispersion reveal the effect of turbulence, multiple velocity
components and collision on broad O~{\small VI} profiles. There is a
significant variation of O~{\small VI} column density on all scales studied
{(0.0025$\degr$ - 6.35$\degr$)}. The smallest scale for which O~{\small VI}
column density variations has been found is {$\bigtriangleup \theta$
$\sim$~9$\arcsec$}. Comparison of the O~{\small VI} velocity profiles with
Fe~{\small II} indicates the presence of intermediate velocity cloud (IVC)
and/or high velocity cloud (HVC) components in the O~{\small VI} absorption.


title: Complex systems: physics beyond physics

abstract:
  Complex systems are characterized by specific time-dependent interactions
among their many constituents. As a consequence they often manifest rich,
non-trivial and unexpected behavior. Examples arise both in the physical and
non-physical world. The study of complex systems forms a new interdisciplinary
research area that cuts across physics, biology, ecology, economics, sociology,
and the humanities. In this paper we review the essence of complex systems from
a physicist's point of view, and try to clarify what makes them conceptually
different from systems that are traditionally studied in physics. Our goal is
to demonstrate how the dynamics of such systems may be conceptualized in
quantitative and predictive terms by extending notions from statistical physics
and how they can often be captured in a framework of co-evolving multiplex
network structures. We mention three areas of complex-systems science that are
currently studied extensively, the science of cities, dynamics of societies,
and the representation of texts as evolutionary objects. We discuss why these
areas form complex systems in the above sense. We argue that there exists
plenty of new land for physicists to explore and that methodical and conceptual
progress is needed most.


title:
Synchronization of cyclic power grids: equilibria and stability of the
  synchronous state

abstract:
  Synchronization is essential for proper functioning of the power grid. We
investigate the synchronous state and its stability for a network with a cyclic
topology and with the evolution of the states satisfying the swing equations.
We calculate the number of stable equilibria and investigate both the linear
and nonlinear stability of the synchronous state. The linear stability analysis
shows that the stability of the state, determined by the smallest nonzero
eigenvalue, is inversely proportional to the size of the network. The nonlinear
stability, which we calculated by comparing the potential energy of the type-1
saddles with that of the stable synchronous state, depends on the network size
($N$) in a more complicated fashion. In particular we find that when the
generators and consumers are evenly distributed in an alternating way, the
energy barrier, preventing loss of synchronization approaches a constant value.
For a heterogeneous distribution of generators and consumers, the energy
barrier will decrease with $N$. The more heterogeneous the distribution is, the
stronger the energy barrier depends on $N$. Finally, we found that by comparing
situations with equal line loads in cyclic and tree networks, tree networks
exhibit reduced stability. This difference disappears in the limit of
$N\to\infty$. This finding corroborates previous results reported in the
literature and suggests that cyclic (sub)networks may be applied to enhance
power transfer while maintaining stable synchronous operation.


title: Reducing Opacity to Linearizability: A Sound and Complete Method

abstract:
  Transactional memory is a mechanism that manages thread synchronisation on
behalf of a programmer so that blocks of code execute with an illusion of
atomicity. The main safety criterion for transactional memory is opacity, which
defines conditions for serialising concurrent transactions.
  Proving opacity is complicated because it allows concurrent transactions to
observe distinct memory states, while TM implementations are typically based on
one single shared store. This paper presents a sound and complete method, based
on coarse-grained abstraction, for reducing proofs of opacity to the relatively
simpler correctness condition: linearizability. We use our methods to verify
TML and NORec from the literature and show our techniques extend to relaxed
memory models by showing that both are opaque under TSO without requiring
additional fences. Our methods also elucidate TM designs at higher level of
abstraction; as an application, we develop a variation of NORec with fast-path
reads transactions. All our proofs have been mechanised, either in the Isabelle
theorem prover or the PAT model checker.


title:
A calculation scheme for spectral densities of strongly correlated
  electron systems using exact diagonalization of dynamical mean field theory

abstract:
  A new approach for calculating spectral density functions of strongly
correlated electron systems is proposed within the exact diagonalization method
of dynamical mean-field theory (DMFT). This approach is based on the analytic
continuation of spectral density function obtained by conventional exact
diagonalization method of DMFT and its results are more reasonable in shape. As
an example of its application, the Mott transition in a strongly correlated
electron system is investigated using this new approach.