title: Density of States for Random Band Matrices in two dimensions

abstract:
  We consider a two dimensional random band matrix ensemble, in the limit of
infinite volume and fixed but large band width $W$. For this model we
rigorously prove smoothness of the averaged density of states. We also prove
that the resulting expression coincides with Wigner's semicircle law with a
precision $W^{-2+\delta },$ where $\delta\to 0$ when $W\to \infty.$ The proof
uses the supersymmetric approach and extends results by Disertori, Pinson and
Spencer from three to two dimensions.


title: Asymptotically Optimal Algorithms for Budgeted Multiple Play Bandits

abstract:
  We study a generalization of the multi-armed bandit problem with multiple
plays where there is a cost associated with pulling each arm and the agent has
a budget at each time that dictates how much she can expect to spend. We derive
an asymptotic regret lower bound for any uniformly efficient algorithm in our
setting. We then study a variant of Thompson sampling for Bernoulli rewards and
a variant of KL-UCB for both single-parameter exponential families and bounded,
finitely supported rewards. We show these algorithms are asymptotically
optimal, both in rateand leading problem-dependent constants, including in the
thick margin setting where multiple arms fall on the decision boundary.


title: Some Results on Cyclic Interval Edge Colorings of Graphs

abstract:
  A proper edge coloring of a graph $G$ with colors $1,2,\dots,t$ is called a
\emph{cyclic interval $t$-coloring} if for each vertex $v$ of $G$ the edges
incident to $v$ are colored by consecutive colors, under the condition that
color $1$ is considered as consecutive to color $t$. We prove that a bipartite
graph $G$ with even maximum degree $\Delta(G)\geq 4$ admits a cyclic interval
$\Delta(G)$-coloring if for every vertex $v$ the degree $d_G(v)$ satisfies
either $d_G(v)\geq \Delta(G)-2$ or $d_G(v)\leq 2$. We also prove that every
Eulerian bipartite graph $G$ with maximum degree at most $8$ has a cyclic
interval coloring. Some results are obtained for $(a,b)$-biregular graphs, that
is, bipartite graphs with the vertices in one part all having degree $a$ and
the vertices in the other part all having degree $b$; it has been conjectured
that all these have cyclic interval colorings. We show that all
$(4,7)$-biregular graphs as well as all $(2r-2,2r)$-biregular ($r\geq 2$)
graphs have cyclic interval colorings. Finally, we prove that all complete
multipartite graphs admit cyclic interval colorings; this settles in the
affirmative, a conjecture of Petrosyan and Mkhitaryan.


title:
The structure of product bases of
  $\mathbb{C}^{2}\bigotimes\mathbb{C}^{n}$

abstract:
  In this paper, we mainly characterize the structure of product bases of the
complex vector space
  $\mathbb{C}^{2}\bigotimes\mathbb{C}^{n}$. It gives an answer to the
conjecture in case of $d=2n$ proposed by McNulty et al in 2016. As the
application of the result, we obtain all the product bases of a bipartite
system $\mathbb{C}^{2}\bigotimes\mathbb{C}^{n}$. It is helpful to review the
structure of all the product bases of $\mathbb{C}^{2}\bigotimes\mathbb{C}^{2}$
and $\mathbb{C}^{2}\bigotimes\mathbb{C}^{3}$, which given by McNulty et al.


title:
A study of the process $e^+ +e^- \to e^+ +e^- p \bar {p}$ by the
  two-photon mechanism $\gamma \gamma \to p \bar {p}$ at high energies

abstract:
  In this paper we consider the exclusive production of proton-antiproton pairs
in the interaction between two quasireal photons in $e^+e^-$ collision. The
differential and total cross section of the process $\gamma \gamma \to p\bar
{p}$ at a beam energy of photons from 2.1 GeV to 4.5 GeV in the center-of-mass
and for different values of $|cos\theta^{\ast}|$ is calculated. At energy
$<\sqrt {s_{e^+e^-}}>$=197 \,\,GeV the total cross section process o0f the $e^+
+e^- \to e^+ +e^- +p +\bar {p}$ is calculated by the two-photon mechanism. The
results are in satisfactory agreement with the experimental data.


title: Well-balanced finite difference WENO schemes for the blood flow model

abstract:
  The blood flow model maintains the steady state solutions, in which the flux
gradients are non-zero but exactly balanced by the source term. In this paper,
we design high order finite difference weighted non-oscillatory (WENO) schemes
to this model with such well-balanced property and at the same time keeping
genuine high order accuracy. Rigorous theoretical analysis as well as extensive
numerical results all indicate that the resulting schemes verify high order
accuracy, maintain the well-balanced property, and keep good resolution for
smooth and discontinuous solutions.


title:
Linearized stability theorem for invariant and quasi-invariant parabolic
  differential equations in Banach manifolds with applications to free boundary
  problems

abstract:
  If a differential equation in a Banach manifold is invariant or
quasi-invariant under the action of one or more Lie groups, then its stationary
points cannot be isolated, so that classical linearized stability theorem does
not apply to it. The first main purpose of this paper is to establish a
linearized stability theorem for parabolic differential equations in Banach
manifolds which are either invariant or quasi-invariant under actions of a
number of Lie groups. The second purpose of this paper is to apply this theorem
to analyze stability of stationary solutions of some free boundary problems. In
order to apply the abstract result to concrete free boundary problems, Banach
manifold made up of certain kind of domains such as simple domains in
${\mathbf{R}}^n$ is a fundamental tool which seems to have not been
well-studied in the literature yet. Hence in this paper we also make some basic
investigation to a such manifold. In Section 5 we use Nash-Moser implicit
function theorem to prove an interesting result for an obstacle problem which
says that if the domain $\Omega$ of this obstacle problem is a small
perturbation of a sphere then its interface $\Gamma$ is smooth and depends on
$\Omega$ smoothly. By using these results, in the last section we prove
asymptotic stability of radial stationary solution of a free boundary problem
modeling the growth of necrotic tumors, which has been kept open for over ten
years.


title:
Numeric calculation of antiferromagnetic resonance frequencies for the
  noncollinear antiferromagnet

abstract:
  We present an algorithm for the numeric calculation of antiferromagnetic
resonance frequencies for the non-collinear antiferromagnets of general type.
This algorithm uses general exchange symmetry approach \cite{andrmar} and is
applicable for description of low-energy dynamics of an arbitrary noncollinear
spin structure in weak fields. Algorithm is implemented as a MatLab and C++
program codes, which are available for download. Program codes are tested
against some representative analytically solvable cases.


title: Online Packet Scheduling with Bounded Delay and Lookahead

abstract:
  We study the online bounded-delay packet scheduling problem (BDPS), where
packets of unit size arrive at a router over time and need to be transmitted
over a network link. Each packet has two attributes: a non-negative weight and
a deadline for its transmission. The objective is to maximize the total weight
of the transmitted packets. This problem has been well studied in the
literature, yet its optimal competitive ratio remains unknown: the best upper
bound is $1.828$, still quite far from the best lower bound of $\phi \approx
1.618$.
  In the variant of BDPS with $s$-bounded instances, each packet can be
scheduled in at most $s$ consecutive slots, starting at its release time. The
lower bound of $\phi$ applies even to the special case of $2$-bounded
instances, and a $\phi$-competitive algorithm for $3$-bounded instances was
given in Chin et al. Improving that result, and addressing a question posed by
Goldwasser, we present a $\phi$-competitive algorithm for $4$-bounded
instances.
  We also study a variant of BDPS where an online algorithm has the additional
power of $1$-lookahead, knowing at time $t$ which packets will arrive at time
$t+1$. For BDPS with $1$-lookahead restricted to $2$-bounded instances, we
present an online algorithm with competitive ratio $(\sqrt{13} - 1)/2 \approx
1.303$ and we prove a nearly tight lower bound of $(1 + \sqrt{17})/4 \approx
1.281$.


title:
Design of 280 GHz feedhorn-coupled TES arrays for the balloon-borne
  polarimeter SPIDER

abstract:
  We describe 280 GHz bolometric detector arrays that instrument the
balloon-borne polarimeter SPIDER. A primary science goal of SPIDER is to
measure the large-scale B-mode polarization of the cosmic microwave background
in search of the cosmic-inflation, gravitational-wave signature. 280 GHz
channels aid this science goal by constraining the level of B-mode
contamination from galactic dust emission. We present the focal plane unit
design, which consists of a 16$\times$16 array of conical, corrugated feedhorns
coupled to a monolithic detector array fabricated on a 150 mm diameter silicon
wafer. Detector arrays are capable of polarimetric sensing via waveguide
probe-coupling to a multiplexed array of transition-edge-sensor (TES)
bolometers. The SPIDER receiver has three focal plane units at 280 GHz, which
in total contains 765 spatial pixels and 1,530 polarization sensitive
bolometers. By fabrication and measurement of single feedhorns, we demonstrate
14.7$^{\circ}$ FHWM Gaussian-shaped beams with $<$1% ellipticity in a 30%
fractional bandwidth centered at 280 GHz. We present electromagnetic
simulations of the detection circuit, which show 94% band-averaged,
single-polarization coupling efficiency, 3% reflection and 3% radiative loss.
Lastly, we demonstrate a low thermal conductance bolometer, which is
well-described by a simple TES model and exhibits an electrical noise
equivalent power (NEP) = 2.6 $\times$ 10$^{-17}$ W/$\sqrt{\mathrm{Hz}}$,
consistent with the phonon noise prediction.


title: Approaching the Cramer-Rao Bound in Weak Lensing with PDF Symmetrization

abstract:
  Weak lensing statistics is typically measured as weighted sum of shear
estimators or their products (shear-shear correlation). The weighting schemes
are designed in the hope of minimizing the statistical error without
introducing systematic errors. It would be ideal to approach the Cramer-Rao
bound (the lower bound of the statistical uncertainty) in shear statistics,
though it is generally difficult to do so in practice. The reasons may include:
difficulties in galaxy shape measurement, inaccurate knowledge of the
probability-distribution-function (PDF) of the shear estimator,
misidentification of point sources as galaxies, etc.. Using the shear
estimators defined in Zhang et al. (2015), we show that one can overcome all
these problems, and allow shear measurement accuracy to approach the Cramer-Rao
bound. This can be achieved by symmetrizing the PDF of the shear estimator, or
the joint PDF of shear estimator pairs (for shear-shear correlation), without
any prior knowledge of the PDF. Using simulated galaxy images, we demonstrate
that under general observing conditions, this idea works as expected: it
minimizes the statistical uncertainty without introducing systematic error.


title: Multicones, duality and invariance for families of matrices

abstract:
  In this paper we analyze the geometric structure and properties of a certain
class of subsets of $\Bbb R^d$, known in the literature as 1-multicones, and
here simply called multicones, which are quite natural generalizations of the
classical cones. In particular, we introduce and investigate a suitable
extension of the concept of duality to such multicones, which allows us to
treat in a convenient way many issues related to their invariance and strict
invariance for matrices and finite families of matrices. One of the main goals
of our investigations is the detection of sufficient conditions on the
structure of the eigenspaces of a given finite family of matrices to assure the
existence of an embedded pair of invariant multicones, which are the smallest
and the biggest in a suitable and natural sense. The conditions we find also
suggest us a practical computational procedure for the actual construction of
such invariant embedded pair.


title: Coalgebraic Trace Semantics for Buechi and Parity Automata

abstract:
  Despite its success in producing numerous general results on state-based
dynamics, the theory of coalgebra has struggled to accommodate the Buechi
acceptance condition---a basic notion in the theory of automata for infinite
words or trees. In this paper we present a clean answer to the question that
builds on the "maximality" characterization of infinite traces (by Jacobs and
Cirstea): the accepted language of a Buechi automaton is characterized by two
commuting diagrams, one for a least homomorphism and the other for a greatest,
much like in a system of (least and greatest) fixed-point equations. This
characterization works uniformly for the nondeterministic branching and the
probabilistic one; and for words and trees alike. We present our results in
terms of the parity acceptance condition that generalizes Buechi's.


title:
The influence of interaction between quasiparticles on parametric
  resonance process in Bose-Einstein condensates

abstract:
  We analyze the uniform system of weakly interacting bosonic gas undergoing
periodic oscillation of interaction constant. This, within Bogoliubov
approximation, leads to creation of atom pairs with well defined opposite
velocities. We show how interaction between quasiparticles, omitted in the
Bogoliubov approximation, significantly changes the atom pair creation process
and properties of scattered atoms.


title: Fractal Reconnection in Solar and Stellar Environments

abstract:
  Recent space based observations of the Sun revealed that magnetic
reconnection is ubiquitous in the solar atmosphere, ranging from small scale
reconnection (observed as nanoflares) to large scale one (observed as long
duration flares or giant arcades). Often the magnetic reconnection events are
associated with mass ejections or jets, which seem to be closely related to
multiple plasmoid ejections from fractal current sheet. The bursty radio and
hard X-ray emissions from flares also suggest the fractal reconnection and
associated particle acceleration. We shall discuss recent observations and
theories related to the plasmoid-induced-reconnection and the fractal
reconnection in solar flares, and their implication to reconnection physics and
particle acceleration. Recent findings of many superflares on solar type stars
that has extended the applicability of the fractal reconnection model of solar
flares to much a wider parameter space suitable for stellar flares are also
discussed.


title:
Efficient Randomized Algorithms for the Fixed-Precision Low-Rank Matrix
  Approximation

abstract:
  Randomized algorithms for low-rank matrix approximation are investigated,
with the emphasis on the fixed-precision problem and computational efficiency
for handling large matrices. The algorithms are based on the so-called QB
factorization, where Q is an orthonormal matrix. Firstly, a mechanism for
calculating the approximation error in Frobenius norm is proposed, which
enables efficient adaptive rank determination for large and/or sparse matrix.
It can be combined with any QB-form factorization algorithm in which B's rows
are incrementally generated. Based on the blocked randQB algorithm by P.-G.
Martinsson and S. Voronin, this results in an algorithm called randQB EI. Then,
we further revise the algorithm to obtain a pass-efficient algorithm, randQB
FP, which is mathematically equivalent to the existing randQB algorithms and
also suitable for the fixed-precision problem. Especially, randQB FP can serve
as a single-pass algorithm for calculating leading singular values, under
certain condition. With large and/or sparse test matrices, we have empirically
validated the merits of the proposed techniques, which exhibit remarkable
speedup and memory saving over the blocked randQB algorithm. We have also
demonstrated that the single-pass algorithm derived by randQB FP is much more
accurate than an existing single-pass algorithm. And with data from a scenic
image and an information retrieval application, we have shown the advantages of
the proposed algorithms over the adaptive range finder algorithm for solving
the fixed-precision problem.


title: Learning Crosslingual Word Embeddings without Bilingual Corpora

abstract:
  Crosslingual word embeddings represent lexical items from different languages
in the same vector space, enabling transfer of NLP tools. However, previous
attempts had expensive resource requirements, difficulty incorporating
monolingual data or were unable to handle polysemy. We address these drawbacks
in our method which takes advantage of a high coverage dictionary in an EM
style training algorithm over monolingual corpora in two languages. Our model
achieves state-of-the-art performance on bilingual lexicon induction task
exceeding models using large bilingual corpora, and competitive results on the
monolingual word similarity and cross-lingual document classification task.


title:
All-optical production of a superfluid Bose-Fermi mixture of $^6$Li and
  $^7$Li

abstract:
  We report the first all-optical production of a superfluid Bose-Fermi mixture
with two spin states of $^6$Li (fermion) and one spin state of $^7$Li (boson)
under the resonant magnetic field of the s-wave Feshbach resonance of the
fermions. Fermions are cooled efficiently by evaporative cooling and they serve
as coolant for bosons. As a result, a superfluid mixture can be achieved by
using a simple experimental apparatus and procedures, as in the case of the
all-optical production of a single Bose-Einstein condensate (BEC). We show that
the all-optical method enables us to realize variety of ultracold Bose-Fermi
mixtures.


title:
Instabilities and oscillations in coagulation equations with kernels of
  homogeneity one

abstract:
  We discuss the long-time behaviour of solutions to Smoluchowski's coagulation
equation with kernels of homogeneity one, combining formal asymptotics,
heuristic arguments based on linearization, and numerical simulations. The case
of what we call diagonally dominant kernels is particularly interesting. Here
one expects that the long-time behaviour is, after a suitable change of
variables, the same as for the Burgers equation. However, for kernels that are
close to the diagonal one we obtain instability of both, constant solutions and
traveling waves and in general no convergence to N-waves for integrable data.
On the other hand, for kernels not close to the diagonal one these structures
are stable, but the traveling waves have strong oscillations. This has
implications on the approach towards an N-wave for integrable data, which is
also characterized by strong oscillations near the shock front.


title: Superconducting detector of IR single-photons based on thin WSi films

abstract:
  We have developed the deposition technology of WSi thin films 4 to 9 nm thick
with high temperature values of superconducting transition (Tc~4 K). Based on
deposed films there were produced nanostructures with indicative planar sizes
~100 nm, and the research revealed that even on nanoscale the films possess of
high critical temperature values of the superconducting transition (Tc~3.3-3.7K
) which certifies high quality and homogeneity of the films created. The first
experiments on creating superconducting single-photon detectors showed that the
detectors SDE (system detection efficiency) with increasing bias current (Ib)
reaches a constant value of ~30% (for 1550 nm) defined by infrared radiation
absorption by the superconducting structure. To enhance radiation absorption by
the superconductor there were created detectors with cavity structures which
demonstrated a practically constant value of quantum efficiency >65% for bias
currents Ib>=0.6Ic. The minimal dark counts level (DC) made 1 s^-1 limited with
background noise. Hence WSi is the most promising material for creating
single-photon detectors with record SDE/DC ratio and noise equivalent power
(NEP).


title:
Global estimates of errors in quantum computation by the Feynman-Vernon
  formalism

abstract:
  The operation of a quantum computer is considered as a general quantum
operation on a mixed state on many qubits followed by a measurement. The
general quantum operation is further represented as a Feynman-Vernon double
path integral over the histories of the qubits and of an environment, and
afterward tracing out the environment. The qubit histories are taken to be
paths on the two-sphere $S^2$ as in Klauder's coherent-state path integralof
spin, and the environment is assumed to consist of harmonic oscillators
initially in thermal equilibrium, and linearly coupled to to qubit operators
$\hat{S}_z$. The environment can then be integrated out to give a
Feynman-Vernon influence action coupling the forward and backward histories of
the qubits. This representation allows to derive in a simple way estimates that
the total error of operation of a quantum computer without error correction
scales linearly with the number of qubits and the time of operation. It also
allows to discuss Kitaev's toric code interacting with an environment in the
same manner.


title: Physics at a 100 TeV pp collider: Higgs and EW symmetry breaking studies

abstract:
  This report summarises the physics opportunities for the study of Higgs
bosons and the dynamics of electroweak symmetry breaking at the 100 TeV pp
collider.


title: Faithful quantum state transfer between weakly coupled qubits

abstract:
  One of the strengths of quantum information theory is that it can treat
quantum states without referring to their particular physical representation.
In principle, quantum states can be therefore fully swapped between various
quantum systems by their mutual interaction and this quantum state transfer is
crucial for many quantum communication and information processing tasks. In
practice, however, the achievable interaction time and strength are often
limited by decoherence. Here we propose and experimentally demonstrate a
procedure for faithful quantum state transfer between two weakly interacting
qubits. Our scheme enables a probabilistic yet perfect unidirectional transfer
of an arbitrary unknown state of a source qubit onto a target qubit prepared
initially in a known state. The transfer is achieved by a combination of a
suitable measurement of the source qubit and quantum filtering on the target
qubit depending on the outcome of measurement on the source qubit. We
experimentally verify feasibility and robustness of the transfer using a linear
optical setup with qubits encoded into polarization states of single photons.


title:
Integrated simulation of magnetic-field-assist fast ignition laser
  fusion

abstract:
  To enhance the core heating efficiency in fast ignition laser fusion, the
concept of relativistic electron beam guiding by external magnetic fields was
evaluated by integrated simulations for FIREX class targets. For the
cone-attached shell target case, the core heating performance is deteriorated
by applying magnetic fields since the core is considerably deformed and the
most of the fast electrons are reflected due to the magnetic mirror formed
through the implosion. On the other hand, in the case of cone-attached solid
ball target, the implosion is more stable under the kilo-tesla-class magnetic
field. In addition, feasible magnetic field configuration is formed through the
implosion. As the results, the core heating efficiency becomes double by
magnetic guiding. The dependence of core heating properties on the heating
pulse shot timing was also investigated for the solid ball target.


title:
Role of dressed-state interference in electromagnetically induced
  transparency

abstract:
  Electromagnetically induced transparency (EIT) in three-level systems uses a
strong control laser on one transition to modify the absorption of a weak probe
laser on a second transition. The control laser creates dressed states whose
decay pathways show interference. We study the role of dressed-state
interference in causing EIT in the three types of three-level systems -- lambda
($\Lambda$), ladder ($\Xi$), and vee (V). In order to get realistic values for
the linewidths of the energy levels involved, we consider appropriate hyperfine
levels of $^{87}$Rb. For such realistic systems, we find that dressed-state
interference causes probe absorption---given by the imaginary part of the
susceptibility---to go to zero in a $\Lambda$ system, but plays a negligible
role in $\Xi$ and V systems.


title:
Whitney numbers of arrangements via measure concentration of intrinsic
  volumes

abstract:
  We verify the Rota-Heron-Welsh conjecture for matroids realizable as
c-arrangements: the coefficients of the characteristic polynomial of the
associated matroid are log-concave. This family of matroids strictly contains
that of complex hyperplane arrangements. Our proof combines the study of
intrinsic volumes of certain extensions of arrangements and the Levy--Milman
measure concentration phenomenon on realization spaces of arrangements.


title: Negative and nonlinear magnetoresistance effect in silicon strip

abstract:
  Both negative magnetoresistance and nonlinear magnetoresisitance were
observed in silicon strip nuclear radiation detector in room temperature if we
applied high magnetic field intensity in different direction. This result is
different with former report. We believe this is the result of coaction of high
electric field (Gunn effect) and high magnetic field, or because of the
variation of number of carriers and the carriers mobility. The weak
localization and Landau energy levels also affect the magnetoresistance.
Different crystal orientations have different energy band structures. Complex
band structures lead complex carriers mobility plus Landau energy levels. So
the magnetoresisitance effect is anisotropy.


title:
An efficiently and tunable switch between slow- and fast-light in double
  mode with an optomechanical system

abstract:
  We study the dynamics of a driven optomechanical cavity coupled to a charged
nanomechanical resonator via Coulomb interaction. We find the tunable switch
between slow-and fast- light in double-mode can be observed from the output
field by adjusting the laser-cavity detuning in this coupled system. Moreover,
the requencies of signal light can be tuned by Coulomb coupling strength. The
proposal may have potential application in optical communcation and nonlinear
optics.


title: Bayesian inference on group differences in multivariate categorical data

abstract:
  Multivariate categorical data are common in many fields. We are motivated by
election polls studies assessing evidence of changes in voters opinions with
their candidates preferences in the 2016 United States Presidential primaries
or caucuses. Similar goals arise routinely in several applications, but current
literature lacks a general methodology which combines flexibility, efficiency,
and tractability in testing for group differences in multivariate categorical
data at different---potentially complex---scales. We address this goal by
leveraging a Bayesian representation which factorizes the joint probability
mass function for the group variable and the multivariate categorical data as
the product of the marginal probabilities for the groups, and the conditional
probability mass function of the multivariate categorical data, given the group
membership. To enhance flexibility, we define the conditional probability mass
function of the multivariate categorical data via a group-dependent mixture of
tensor factorizations, thus facilitating dimensionality reduction and borrowing
of information, while providing tractable procedures for computation, and
accurate tests assessing global and local group differences. We compare our
methods with popular competitors, and discuss improved performance in
simulations and in American election polls studies.


title: Quantum phase transitions and multicriticality in Ta(Fe1-xVx)2

abstract:
  We present a comprehensive study of synthesis, structure analysis, transport
and thermodynamic properties of the C14 Laves phase Ta(Fe1-xVx)2. Our
measurements confirm the appearance of spin-density wave (SDW) order within a
dome-like region of the x - T phase diagram with vanadium content 0.02 < x <
0.3. Our results indicate that on approaching TaFe2 from the vanadium-rich
side, ferromagnetic (FM) correlations increase faster than the
antiferromagnetic (AFM) ones. This results in an exchange-enhanced
susceptibility and in the suppression of the SDW transition temperature for x <
0.13 forming the dome-like shape of the phase diagram. This effect is strictly
related to a significant lattice distortion of the crystal structure manifested
in the c/a ratio. At x = 0.02 both FM and AFM energy scales have similar
strength and the system remains paramagnetic down to 2 K with an extremely
large Stoner enhancement factor of about 400. Here, spin fluctuations dominate
the temperature dependence of the resistivity \rho ~ T ^ 3/2 and of the
specific heat C/T ~ - log(T) which deviate from their conventional Fermi liquid
forms, inferring the presence of a quantum critical point of dual nature.


title:
First measurement of polarisation asymmetry of a gamma-ray beam between
  1.74 to 74 MeV with the HARPO TPC

abstract:
  Current $\gamma$-ray telescopes suffer from a gap in sensitivity in the
energy range between 100keV and 100MeV, and no polarisation measurement has
ever been done on cosmic sources above 1MeV. Past and present e$^+$e$^-$ pair
telescopes are limited at lower energies by the multiple scattering of
electrons in passive tungsten converter plates. This results in low angular
resolution, and, consequently, a drop in sensitivity to point sources below
1GeV. The polarisation information, which is carried by the azimuthal angle of
the conversion plane, is lost for the same reasons.
  HARPO (Hermetic ARgon POlarimeter) is an R\&D program to characterise the
operation of a gaseous detector (a Time Projection Chamber or TPC) as a high
angular-resolution and sensitivity telescope and polarimeter for $\gamma$ rays
from cosmic sources. It represents a first step towards a future space
instrument in the MeV-GeV range.
  We built and characterised a 30cm cubic demonstrator [SPIE 91441M], and put
it in a polarised $\gamma$-ray beam at the NewSUBARU accelerator in Japan. Data
were taken at photon energies from 1.74MeV to 74MeV, and with different
polarisation configurations.
  We describe the experimental setup in beam. We then describe the software we
developed to reconstruct the photon conversion events, with special focus on
low energies. We also describe the thorough simulation of the detector used to
compare results. Finally we will present the performance of the detector as
extracted from this analysis and preliminary measurements of the polarisation
asymmetry.
  This beam-test qualification of a gas TPC prototype in a $\gamma$-ray beam
could open the way to high-performance $\gamma$-ray astronomy and polarimetry
in the MeV-GeV energy range in the near future.


title:
Zeta distributions generated by multidimensional polynomial Euler
  products with complex coefficients

abstract:
  In the present paper, we treat multidimensional polynomial Euler products
with complex coefficients on ${\mathbb{R}}^d$. We give necessary and sufficient
conditions for the multidimensional polynomial Euler products to generate
infinitely divisible, quasi-infinitely divisible but non-infinitely divisible
or not even characteristic functions by using Baker's theorem. Moreover, we
give many examples of zeta distributions on ${\mathbb{R}}^d$ generated by the
multidimensional polynomial Euler products with complex coefficients. Finally,
we consider applications to analytic number theory.


title:
An adaptive MCMC method for multiple changepoint analysis with
  applications to large datasets

abstract:
  We consider the problem of Bayesian inference for changepoints where the
number and position of the changepoints are both unknown. In particular, we
consider product partition models where it is possible to integrate out model
parameters for the regime between each changepoint, leaving a posterior
distribution over a latent vector indicating the presence or not of a
changepoint at each observation. The same problem setting has been considered
by Fearnhead (2006) where one can use filtering recursions to make exact
inference. However the complexity of this algorithm depends quadratically on
the number of observations. Our approach relies on an adaptive Markov Chain
Monte Carlo (MCMC) method for finite discrete state spaces. We develop an
adaptive algorithm which can learn from the past states of the Markov chain in
order to build proposal distributions which can quickly discover where
changepoint are likely to be located. We prove that our algorithm leaves the
posterior distribution ergodic. Crucially, we demonstrate that our adaptive
MCMC algorithm is viable for large datasets for which the filtering recursions
approach is not. Moreover, we show that inference is possible in a reasonable
time.


title:
The 7Be(n,alpha)4He reaction and the Cosmological Lithium Problem:
  measurement of the cross section in a wide energy range at n_TOF (CERN)

abstract:
  The energy-dependent cross section of the 7Be(n,alpha)4He reaction, of
interest for the so-called Cosmological Lithium Problem in Big Bang
Nucleosynthesis, has been measured for the first time from 10 meV to 10 keV
neutron energy. The challenges posed by the short half-life of 7Be and by the
low reaction cross section have been overcome at n_TOF thanks to an
unprecedented combination of the extremely high luminosity and good resolution
of the neutron beam in the new experimental area (EAR2) of the n_TOF facility
at CERN, the availability of a sufficient amount of chemically pure 7Be, and a
specifically designed experimental setup. Coincidences between the two
alpha-particles have been recorded in two Si-7Be-Si arrays placed directly in
the neutron beam. The present results are consistent, at thermal neutron
energy, with the only previous measurement performed in the 60's at a nuclear
reactor. The energy dependence here reported clearly indicates the inadequacy
of the cross section estimates currently used in BBN calculations. Although new
measurements at higher neutron energy may still be needed, the n_TOF results
hint to a minor role of this reaction in BBN, leaving the long-standing
Cosmological Lithium problem unsolved.


title:
Irreversibility of Asymptotic Entanglement Manipulation Under Quantum
  Operations Completely Preserving Positivity of Partial Transpose

abstract:
  We demonstrate the irreversibility of asymptotic entanglement manipulation
under quantum operations that completely preserve the positivity of partial
transpose (PPT), resolving a major open problem in quantum information theory.
Our key tool is a new efficiently computable additive lower bound for the
asymptotic relative entropy of entanglement with respect to PPT states, which
can be used to evaluate the entanglement cost under local operations and
classical communication (LOCC). We find that for any rank-two mixed state
supporting on the $3\otimes3$ antisymmetric subspace, the amount of distillable
entanglement by PPT operations is strictly smaller than one entanglement bit
(ebit) while its entanglement cost under PPT operations is exactly one ebit. As
byproduct, we find that for this class of states, both the Rains' bound and its
regularization, are strictly less than the asymptotic relative entropy of
entanglement. So, in general, there is no unique entanglement measure for the
manipulation of entanglement by PPT operations. We further show a computable
sufficient condition for the irreversibility of entanglement distillation by
LOCC (or PPT) operations.


title: Surface magnetism of strontium titanate

abstract:
  SrTiO3 plays a central role in oxide electronics. It is the substrate of
choice for functional oxide heterostructures based on perovskite-structure
thin-film stacks, and its surface or interface with a polar oxide such as
LaAlO3 can become a two-dimensional conductor because of electronic
reconstruction or the presence of oxygen defects. Inconsistent reports of
magnetic order in SrTiO3 abound in the literature. Here we report a systematic
experimental study aimed at establishing how and when SrTiO3 can develop a
magnetic moment at room temperature. Polished 100, 110 or 111 crystal slices
from four different suppliers are characterized before and after vacuum
annealing at 750 {\deg}C, both in single-crystal and powdered form. Impurity
content is analysed at the surface and in the bulk. Besides the underlying
intrinsic diamagnetism of SrTiO3, magnetic signals are of three types-a Curie
law susceptibility due to dilute magnetic impurities at the ppm level, a
hysteretic, temperature-dependent ferromagnetic impurity contribution, and a
practically-anhysteretic, defect-related temperature-independent component that
saturates in about 200 mT. The latter component is intrinsic. It is often the
largest, reaching 10 Bohr magnetons per nm2 of surface area or more and
dominating the magnetic response in low fields at room temperature. It is
associated with defects near the surface, and can be destroyed by treatment
with Tiron (C6H4Na2O8S2), an electron donor molecule that forms a strong
complex with titanium at the surface. The origin of this unusual
high-temperature ferromagnetic-like response is discussed.


title:
Probing transfer to unbound states of the ejectile with weakly bound 7Li
  on 93Nb

abstract:
  The two-step process of transfer followed by breakup is explored by measuring
a rather complete set of exclusive data for reaction channels populating states
in the ejectile continua of the $^7$Li+$^{93}$Nb system at energies close to
the Coulomb barrier. The cross sections for $\alpha+\alpha$ events from one
proton pickup were found to be smaller than those for $\alpha+d$ events from
one neutron stripping and $\alpha+t$ events from direct breakup of $^7$Li.
Coupled channels Born approximation and continuum discretized coupled channels
calculations describe the data well and support the conclusion that the
$\alpha+d$ and $\alpha+\alpha$ events are produced by direct transfer to
unbound states of the ejectile.


title: Variance Allocation and Shapley Value

abstract:
  Motivated by the problem of utility allocation in a portfolio under a
Markowitz mean-variance choice paradigm, we propose an allocation criterion for
the variance of the sum of $n$ possibly dependent random variables. This
criterion, the Shapley value, requires to translate the problem into a
cooperative game. The Shapley value has nice properties, but, in general, is
computationally demanding. The main result of this paper shows that in our
particular case the Shapley value has a very simple form that can be easily
computed. The same criterion is used also to allocate the standard deviation of
the sum of $n$ random variables and a conjecture about the relation of the
values in the two games is formulated.


title:
Identification of a possible superconducting transition above room
  temperature in natural graphite crystals

abstract:
  Measuring with high precision the electrical resistance of highly ordered
natural graphite samples from a Brazil mine, we have identified a transition at
$\sim$350~K with $\sim$40~K transition width. The step-like change in
temperature of the resistance, its magnetic irreversibility and time dependence
after a field change, consistent with trapped flux and flux creep, and the
partial magnetic flux expulsion obtained by magnetization measurements, suggest
the existence of granular superconductivity below 350~K. The zero-field virgin
state can only be reached again after zero field cooling the sample from above
the transition. Paradoxically, the extraordinarily high transition temperature
we found for this and several other graphite samples is the reason why this
transition remained undetected so far. The existence of well ordered
rhombohedral graphite phase in all measured samples has been proved by x-rays
diffraction measurements, suggesting its interfaces with the Bernal phase as a
possible origin for the high-temperature superconductivity, as theoretical
studies predicted. The localization of granular superconductivity at these two
dimensional interfaces prevents the observation of a zero resistance state or
of a full Meissner state.


title: Evolution of the stellar-merger red nova V1309 Scorpii: SED analysis

abstract:
  One very important object for understanding the nature of red novae is V1309
Sco. Its pre-outburst observations showed that, before its red-nova eruption in
2008, it was a contact binary quickly evolving to the merger of the components.
It thus provided us with a direct evidence that the red novae result from
stellar mergers. We analyse the spectral energy distribution (SED) of the
object and its evolution with time. From various optical and infrared surveys
and observing programmes carried out with OGLE, HST, VVV, Gemini South, WISE,
Spitzer, and Herschel we constructed observed SED in 2010 and 2012. Some
limited data are also available for the red-nova progenitor in 2007. We analyse
the data with our model of a dusty envelope surrounding a central star. Dust
was present in the pre-outburst state of V1309 Sco. Its high temperature
(900-1000 K) suggests that this was a freshly formed dust in a presumable
mass-loss from the spiralling-in binary. Shortly after its 2008 eruption,
V1309~Sco became almost completely embedded in dust. The parameters
(temperature, dimensions) of the dusty envelope in 2010 and 2012 evidence that
we then observed matter lost by the object during the 2008 outburst. Its mass
is at least $10^{-3}\,M_\odot$. The object remains quite luminous, although
since its maximum brightness in September 2008, it has faded in luminosity by a
factor of ~50 (in 2012). Far infrared data from Herschel reveal presence of a
cold (~30 K) dust at a distance of a few thousand AU from the object. This
conclusion could be verified by submillimeter interferometric observations.


title:
Gating classical information flow through spin chains by quantum phase
  transitions

abstract:
  To push commercial electronics beyond its current size limits, atomic-scale
communication channels and logic units need to be designed, making the use of
quantum entities an imperative. In this regime, quantum fluctuations naturally
become prominent, and are generally considered to be detrimental. Here we show
that for spin-based information processing, these fluctuations can be uniquely
exploited to gate the flow of classical binary information across a magnetic
chain. Moreover, this information flow can be controlled with a modest external
magnetic field that drives the system through different many-body quantum
phases in which the orientation of the final spin does or does not reflect the
orientation of the initial input. Our results are general for a wide class of
anisotropic spin chains that act as magnetic cellular automata, and suggest
that quantum fluctuations may play a unique role in driving classical
information flow at the atomic scale.

categories: cond-mat.mes-hall cond-mat.stat-mech cond-mat.str-el quant-ph


title:
The ionization rates of galactic nuclei and disks from Herschel/HIFI
  observations of water and its associated ions

abstract:
  (Abridged) We present Herschel/HIFI spectra of the H2O 1113 GHz and H2O+ 1115
GHz lines toward five nearby prototypical starburst/AGN systems, and OH+ 971
GHz spectra toward three of these. The beam size of 20" corresponds to
resolutions between 0.35 and 7 kpc. The observed line profiles range from pure
absorption (NGC 4945, M82) to P-Cygni indicating outflow (NGC 253, Arp 220) and
inverse P-Cygni indicating infall (Cen A). The similarity of the H2O, OH+, and
H2O+ profiles to each other and to HI indicates that diffuse and dense gas
phases are well mixed. We estimate column densities assuming negligible
excitation (for absorption features) and using a non-LTE model (for emission
features), adopting calculated collision data for H2O and OH+, and rough
estimates for H2O+. Column densities range from ~10^13 to ~10^15 cm^-2 for each
species, and are similar between absorption and emission components, indicating
that the nuclear region does not contribute much to the emission in these
ground-state lines. The N(H2O)/N(H2O+) ratios of 1.4-5.6 indicate an origin of
the lines in diffuse gas, and the N(OH+)/N(H2O+) ratios of 1.6-3.1 indicate a
low H2 fraction (~11%) in the gas.
  Adopting recent Galactic values for the average gas density and the
ionization efficiency, we find ionization rates for our sample galaxies of
~3x10^-16 s^-1 which are similar to the value for the Galactic disk, but ~10x
below that of the Galactic Center and ~100x below estimates for AGN from
excited-state H3O+ lines. We conclude that the ground-state lines of water and
its associated ions probe primarily non-nuclear gas in the disks of these
centrally active galaxies. Our data thus provide evidence for a decrease in
ionization rate by a factor of ~10 from the nuclei to the disks of galaxies, as
found before for the Milky Way.


title: Invariance principle and rigidity of high entropy measures

abstract:
  A deep analysis of the Lyapunov exponents, for stationary sequence of
matrices going back to Furstenberg, for more general linear cocycles by
Ledrappier and generalized to the context of non-linear cocycles by Avila and
Viana, gives an invariance principle for invariant measures with vanishing
central exponents. In this paper, we give a new criterium formulated in terms
of entropy for the invariance principle and in particular, obtain a simpler
proof for some of the known invariance principle results.
  As a byproduct, we study ergodic measures of partially hyperbolic
diffeomorphisms whose center foliation is 1-dimensional and forms a circle
bundle. We show that for any such C2 diffeomorphism which is accessible, weak
hyperbolicity of ergodic measures of high entropy implies that the system
itself is of rotation type.


title: Spinning particles moving around black holes: integrability and chaos

abstract:
  The motion of a stellar compact object around a supermassive black hole can
be approximated by the motion of a spinning test particle. The equations of
motion describing such systems are in general non-integrable, and therefore,
chaotic motion should be expected. This article discusses the integrability
issue of the spinning particle for the cases of Schwarzschild and Kerr
spacetime, and then it focuses on a canonical Hamiltonian formalism where the
spin of the particle is included only up to the linear order.


title:
A New Drop Fluidics Enabled by Magnetic Field Mediated Elasto-Capillary
  Transduction

abstract:
  This research introduces a new drop fluidics, which uses a deformable and
stretchable elastomeric film as the platform, instead of the commonly used
rigid supports. Such a soft film impregnated with magnetic particles can be
modulated with an external electromagnetic field that produces a vast array of
topographical landscapes with varying surface curvature, which, in conjunction
with capillarity, can direct and control motion of water droplets efficiently
and accurately. When a thin layer of oil is present on this film that is
deformed locally, a centrosymmetric wedge is formed. A water droplet placed on
this oil laden film becomes asymmetrically deformed thus producing a gradient
of Laplace pressure within the droplet setting it to motion. A simple theory is
presented that accounts for the droplet speed in terms of such geometric
variables as the volume of the droplet and the thickness of the oil film
covering the soft elastomeric film, as well as such material variables as the
viscosity of the oil and interfacial tension of the oil-water interfaces.
Following the verification of the theoretical result using well-controlled
model systems, we demonstrate how the electromagnetically controlled
elasto-capillary force can be used to manipulate the motion of single and/or
multiple droplets on the surface of the elastomeric film and how such
elementary operations as drop fusion and thermally addressed chemical
transformation can be carried out in aqueous droplets. It is expected that the
resulting drop fluidics would be suitable for digital control of drop motion by
simply switching on and off the electromagnetic fields applied at different
positions underneath the elastomeric film. We anticipate that this method of
directing and manipulating water droplets is poised for its applications in
various biochemical reaction engineering, an example of which is Polymerase
Chain Reaction (PCR).


title:
On anisotropy function in crystal growth simulations using Lattice
  Boltzmann equation

abstract:
  In this paper, we present the ability of the Lattice Boltzmann (LB) equation,
usually applied to simulate fluid flows, to simulate various shapes of
crystals. Crystal growth is modeled with a phase-field model for a pure
substance, numerically solved with a LB method in 2D and 3D. This study focuses
on the anisotropy function that is responsible for the anisotropic surface
tension between the solid phase and the liquid phase. The anisotropy function
involves the unit normal vectors of the interface, defined by gradients of
phase-field. Those gradients have to be consistent with the underlying lattice
of the LB method in order to avoid unwanted effects of numerical anisotropy.
Isotropy of the solution is obtained when the directional derivatives method,
specific for each lattice, is applied for computing the gradient terms. With
the central finite differences method, the phase-field does not match with its
rotation and the solution is not any more isotropic. Next, the method is
applied to simulate simultaneous growth of several crystals, each of them being
defined by its own anisotropy function. Finally, various shapes of 3D crystals
are simulated with standard and non standard anisotropy functions which favor
growth in <100>-, <110>- and <111>-directions.


title:
Steering a Predator Robot using a Mixed Frame/Event-Driven Convolutional
  Neural Network

abstract:
  This paper describes the application of a Convolutional Neural Network (CNN)
in the context of a predator/prey scenario. The CNN is trained and run on data
from a Dynamic and Active Pixel Sensor (DAVIS) mounted on a Summit XL robot
(the predator), which follows another one (the prey). The CNN is driven by both
conventional image frames and dynamic vision sensor "frames" that consist of a
constant number of DAVIS ON and OFF events. The network is thus "data driven"
at a sample rate proportional to the scene activity, so the effective sample
rate varies from 15 Hz to 240 Hz depending on the robot speeds. The network
generates four outputs: steer right, left, center and non-visible. After
off-line training on labeled data, the network is imported on the on-board
Summit XL robot which runs jAER and receives steering directions in real time.
Successful results on closed-loop trials, with accuracies up to 87% or 92%
(depending on evaluation criteria) are reported. Although the proposed approach
discards the precise DAVIS event timing, it offers the significant advantage of
compatibility with conventional deep learning technology without giving up the
advantage of data-driven computing.


title: Negative-parity nucleon excited state in nuclear matter

abstract:
  Spectral functions of the nucleon and its negative parity excited state in
nuclear matter are studied using QCD sum rules and the maximum entropy method
(MEM). It is found that in-medium modifications of the spectral functions are
attributed mainly to density dependencies of the $\langle \bar{q}q \rangle $
and $\langle q^{\dagger}q \rangle $ condensates. The MEM reproduces the
lowest-energy peaks of both the positive and negative parity nucleon states at
finite density up to $\rho \sim \rho_N$ (normal nuclear matter density). As the
density grows, the residue of the nucleon ground state decreases gradually
while the residue of the lowest negative parity excited state increases
slightly. On the other hand, the positions of the peaks, which correspond to
the total energies of these states, are almost density independent for both
parity states. The density dependencies of the effective masses and vector
self-energies are also extracted by assuming the mean-field green functions for
the peak states. We find that, as the density increases, the nucleon effective
mass decreases while the vector self-energy increases. The density dependence
of these quantities for the negative parity state on the other hand turns out
to be relatively weak.


title:
Dynamical charge and pseudospin currents in graphene and possible Cooper
  pair formation

abstract:
  Based on the quantum kinetic equations for systems with SU(2) structure,
regularization-free density and pseudospin currents are calculated in graphene
realized as the infinite mass-limit of electrons with quadratic dispersion and
a proper spin-orbit coupling. Correspondingly the currents possess no
quasiparticle part but only anomalous parts. The intraband and interband
conductivities are discussed with respect to magnetic fields and magnetic
domain puddles. It is found that the magnetic field and meanfield of domains
can be represented by an effective Zeeman field. For large Zeeman fields the
dynamical conductivities become independent of the density and are universal in
this sense. The different limits of vanishing density, relaxation, frequency,
and Zeeman field are not interchangeable. The optical conductivity agrees well
with the experimental values using screened impurity scattering and an
effective Zeeman field. The universal value of Hall conductivity is shown to be
modified due to the Zeeman field. The pseudospin current reveals an anomaly
since a quasiparticle part appears though it vanishes for particle currents.
The density and pseudospin response functions to an external electric field are
calculated and the dielectric function is discussed with respect to collective
excitations. A frequency and wave-vector range is identified where the
dielectric function changes sign and the repulsive Coulomb potential becomes
effectively attractive allowing Cooper pairing.


title: Theory of ballistic quantum transport in presence of localized defects

abstract:
  We present an efficient numerical approach for treating ballistic quantum
transport across devices described by tight binding (TB) Hamiltonians
designated to systems with localized potential defects. The method is based on
the wave function matching approach, Lippmann-Schwinger equation (LEQ) and the
scattering matrix formalism. We show that the number of matrix elements of the
Green's function to be evaluated for the unperturbed system can be essentially
reduced by projection of the time reversed scattering wave functions on LEQ
which radically improves the speed and lowers the memory consumption of the
calculations. Our approach can be applied to quantum devices of an arbitrary
geometry and any number of degrees of freedom or leads attached. We provide a
couple of examples of possible applications of the theory, including current
equilibration at the p-n junction in graphene and scanning gate microscopy
mapping of electron trajectories in the magnetic focusing experiment on a
graphene ribbon. Additionally, we provide a simple toy example of electron
transport through 1D wire with added onsite perturbation and obtain a simple
formula for conductance showing that Green's function of the device can be
obtained from the conductance versus impurity strength characteristics.


title:
LOFAR/H-ATLAS: A deep low-frequency survey of the Herschel-ATLAS North
  Galactic Pole field

abstract:
  We present LOFAR High-Band Array (HBA) observations of the Herschel-ATLAS
North Galactic Pole survey area. The survey we have carried out, consisting of
four pointings covering around 142 square degrees of sky in the frequency range
126--173 MHz, does not provide uniform noise coverage but otherwise is
representative of the quality of data to be expected in the planned LOFAR
wide-area surveys, and has been reduced using recently developed `facet
calibration' methods at a resolution approaching the full resolution of the
datasets ($\sim 10 \times 6$ arcsec) and an rms off-source noise that ranges
from 100 $\mu$Jy beam$^{-1}$ in the centre of the best fields to around 2 mJy
beam$^{-1}$ at the furthest extent of our imaging. We describe the imaging,
cataloguing and source identification processes, and present some initial
science results based on a 5-$\sigma$ source catalogue. These include (i) an
initial look at the radio/far-infrared correlation at 150 MHz, showing that
many Herschel sources are not yet detected by LOFAR; (ii) number counts at 150
MHz, including, for the first time, observational constraints on the numbers of
star-forming galaxies; (iii) the 150-MHz luminosity functions for active and
star-forming galaxies, which agree well with determinations at higher
frequencies at low redshift, and show strong redshift evolution of the
star-forming population; and (iv) some discussion of the implications of our
observations for studies of radio galaxy life cycles.


title: Coherent configurations associated with TI-subgroups

abstract:
  Let X be a coherent configuration associated with a transitive group G. In
terms of the intersection numbers of X, a necessary condition for the point
stabilizer of G to be a TI-subgroup, is established. Furthermore, under this
condition, X is determined up to isomorphism by the intersection numbers. It is
also proved that asymptotically, this condition is also sufficient. More
precisely, an arbitrary homogeneous coherent configuration satisfying this
condition is associated with a transitive group, the point stabilizer of which
is a TI-subgroup. As a byproduct of the developed theory, recent results on
pseudocyclic and quasi-thin association schemes are generalized and improved.
In particular, it is shown that any scheme of prime degree p and valency k is
associated with a transitive group, whenever p>1+6k(k-1)^2.


title: A road to reality with topological superconductors

abstract:
  Topological states of matter are a source of low-energy quasiparticles, bound
to a defect or propagating along the surface. In a superconductor these are
Majorana fermions, described by a real rather than a complex wave function. The
absence of complex phase factors promises protection against decoherence in
quantum computations based on topological superconductivity. This is a tutorial
style introduction written for a Nature Physics focus issue on topological
matter.


title:
Parameter Estimation via Conditional Expectation --- A Bayesian
  Inversion

abstract:
  When a mathematical or computational model is used to analyse some system, it
is usual that some parameters resp.\ functions or fields in the model are not
known, and hence uncertain. These parametric quantities are then identified by
actual observations of the response of the real system. In a probabilistic
setting, Bayes's theory is the proper mathematical background for this
identification process. The possibility of being able to compute a conditional
expectation turns out to be crucial for this purpose. We show how this
theoretical background can be used in an actual numerical procedure, and
shortly discuss various numerical approximations.


title:
Creating Feshbach resonances for ultracold molecule formation with
  radiofrequency fields

abstract:
  We show that radiofrequency (RF) radiation may be used to create Feshbach
resonances in ultracold gases of alkali-metal atoms at desired magnetic fields
that are convenient for atomic cooling and degeneracy. For the case of
$^{39}$K+$^{133}$Cs, where there are no RF-free resonances in regions where Cs
may be cooled to degeneracy, we show that a resonance may be created near 21~G
with 69.2~MHz RF radiation. This resonance is almost lossless with circularly
polarized RF, and the molecules created are long-lived even with
plane-polarized RF.


title:
Measurement-induced decoherence and information in double-slit
  interference

abstract:
  The double slit experiment provides a classic example of both interference
and the effect of observation in quantum physics. When particles are sent
individually through a pair of slits, a wave-like interference pattern
develops, but no such interference is found when one observes which "path" the
particles take. We present a model of interference, dephasing, and
measurement-induced decoherence in a one-dimensional version of the double-slit
experiment. Using this model, we demonstrate how the loss of interference in
the system is correlated with the information gain by the measuring
apparatus/observer. In doing so, we give a modern account of measurement in
this paradigmatic example of quantum physics that is accessible to students
taking quantum mechanics at the graduate or senior undergraduate levels.


title: The A-decomposability of the Singer construction

abstract:
  Let $R_s M$ denote the Singer construction on an unstable module $M$ over the
Steenrod algebra $A$ at the prime two; $R_s M$ is canonically a subobject of
$P_s\otimes M$, where $P_s$ is the polynomial algebra on s generators of degree
one. Passage to $A$-indecomposables gives the natural transformation $R_s M
\rightarrow F \otimes_A (P_s \otimes M)$, which identifies with the dual of the
composition of the Singer transfer and the Lannes-Zarati homomorphism.
  The main result of the paper proves the weak generalized algebraic spherical
class conjecture, which was proposed by the first named author. Namely, this
morphism is trivial on elements of positive degree when s>2. The condition s>2
is necessary, as exhibited by the spherical classes of Hopf invariant one and
those of Kervaire invariant one.


title: Central leaves in loop groups

abstract:
  This paper analyses the finer structure of Newton strata in loop groups.
These can be decomposed into so-called central leaves. We define them, and
determine their global geometric structure. We then study the closure of
central leaves, both by proving some general properties and by considering an
illustrative example.


title: Weighted Projective Lines and Rational Surface Singularities

abstract:
  In this paper we study rational surface singularities R with star shaped dual
graphs, and under very mild assumptions on the self-intersection numbers we
give an explicit description of all their special Cohen-Macaulay modules. We do
this by realising R as a certain Z-graded Veronese subring S^x of the
homogeneous coordinate ring S of the Geigle-Lenzing weighted projective line X,
and we realise the special CM modules as explicitly described summands of the
canonical tilting bundle on X. We then give a second proof that these are
special CM modules by comparing qgr S^x and coh X, and we also give a necessary
and sufficient combinatorial criterion for these to be equivalent categories.
In turn, we show that qgr S^x is equivalent to qgr of the reconstruction
algebra, and that the degree zero piece of the reconstruction algebra coincides
with Ringel's canonical algebra. This implies that the reconstruction algebra
contains the canonical algebra, and furthermore its qgr category is derived
equivalent to the canonical algebra, thus linking the reconstruction algebra of
rational surface singularities to the canonical algebra of representation
theory.


title:
Discovering topically- and temporally-coherent events in interaction
  networks

abstract:
  With the increasing use of online communication platforms, such as email,
twitter, and messaging applications, we are faced with a growing amount of data
that combine content (what is said), time (when), and user (by whom)
information. An important computational challenge is to analyze these data,
discover meaningful patterns, and understand what is happening. We consider the
problem of mining online communication data and finding top-k temporal events.
We define a temporal event to be a coherent topic that is discussed frequently,
in a relatively short time span, while the information ow of the event respects
the underlying network structure. We construct our model for detecting temporal
events in two steps. We first introduce the notion of interaction meta-graph,
which connects associated interactions. Using this notion, we define a temporal
event to be a subset of interactions that (i) are topically and temporally
close and (ii) correspond to a tree that captures the information ow. Finding
the best temporal event leads to budget version of the prize-collecting
Steiner-tree (PCST) problem, which we solve using three different methods: a
greedy approach, a dynamic-programming algorithm, and an adaptation to an
existing approximation algorithm. The problem of finding the top- k events
among a set of candidate events maps to maximum set-cover problem, and thus,
solved by greedy. We compare and analyze our algorithms in both synthetic and
real datasets, such as twitter and email communication. The results show that
our methods are able to detect meaningful temporal events.


title:
Integration-by-parts reductions from the viewpoint of computational
  algebraic geometry

abstract:
  Integration-by-parts reductions play a central role in perturbative QFT
calculations. They allow the set of Feynman integrals contributing to a given
observable to be reduced to a small set of basis integrals, and they moreover
facilitate the computation of those basis integrals. We introduce an efficient
new method for generating integration-by-parts reductions. This method
simplifies the task by making use of generalized-unitarity cuts and turns the
problem of finding the needed total derivatives into one of solving certain
polynomial (so-called syzygy) equations.


title: Clusters: age scales for stellar physics

abstract:
  Ages are key to truly understand a large plethora of astrophysical phenomena.
On the other hand, stellar clusters are open windows to understand stellar
evolution, specifically, the change with time and mass of different stellar
properties. As such, they are our laboratories where different theories can be
tested, but without accurate ages, our knowledge would impaired. We revisit
here a large number of age-dating techniques and discuss their advantages and
draw-backs. In addition, a step-by step process is suggested in order to built
a coherent age scale ladder, minimizing the error budget and the sources of
uncertainty.


title: Clique-Width and Directed Width Measures for Answer-Set Programming

abstract:
  Disjunctive Answer Set Programming (ASP) is a powerful declarative
programming paradigm whose main decision problems are located on the second
level of the polynomial hierarchy. Identifying tractable fragments and
developing efficient algorithms for such fragments are thus important
objectives in order to complement the sophisticated ASP systems available to
date. Hard problems can become tractable if some problem parameter is bounded
by a fixed constant; such problems are then called fixed-parameter tractable
(FPT). While several FPT results for ASP exist, parameters that relate to
directed or signed graphs representing the program at hand have been neglected
so far. In this paper, we first give some negative observations showing that
directed width measures on the dependency graph of a program do not lead to FPT
results. We then consider the graph parameter of signed clique-width and
present a novel dynamic programming algorithm that is FPT w.r.t. this
parameter. Clique-width is more general than the well-known treewidth, and, to
the best of our knowledge, ours is the first FPT algorithm for bounded
clique-width for reasoning problems beyond SAT.


title:
Variations of the Interstellar Extinction Law within the Nearest
  Kiloparsec

abstract:
  Multicolor photometry from the Tycho-2 and 2MASS catalogues for 11 990 OB and
30 671 K-type red giant branch stars is used to detect systematic large-scale
variations of the interstellar extinction law within the nearest kiloparsec.
The characteristic of the extinction law, the total-to-selective extinction
ratio $R_V$, which also characterizes the size and other properties of
interstellar dust grains, has been calculated for various regions of space by
the extinction law extrapolation method. The results for the two classes of
stars agree: the standard deviation of the "red giants minus OB" $R_V$
differences within 500 pc of the Sun is 0.2. The detected $R_V$ variations
between 2.2 and 4.4 not only manifest themselves in individual clouds but also
span the entire space near the Sun, following Galactic structures. In the Local
Bubble within about 100 pc of the Sun, $R_V$ has a minimum. In the inner part
of the Gould Belt and at high Galactic latitudes, at a distance of about 150 pc
from the Sun, $R_V$ reaches a maximum and then decreases to its minimum in the
outer part of the Belt and other directions at a distance of about 500 pc from
the Sun, returning to its mean values far from the Sun. The detected maximum of
$R_V$ at high Galactic latitudes is important when allowance is made for the
interstellar extinction toward extragalactic objects. In addition, a monotonic
increase in $R_V$ by 0.3 per kpc toward the Galactic center has been found near
the Galactic equator. It is consistent with the result obtained by Zasowski et
al. (2009) for much of the Galaxy. Ignoring the $R_V$ variations and
traditionally using a single value for the entire space must lead to systematic
errors in the calculated distances reaching 10\%.


title: Getting the Most Neutrinos out of IsoDAR

abstract:
  Several experimental collaborations worldwide intend to test sterile neutrino
models by measuring the disappearance of antineutrinos produced via isotope
decay at rest (IsoDAR). The most advanced of these proposals have very similar
setups, in which a proton beam strikes a target yielding neutrons which are
absorbed by a high isotopic purity 7Li converter, yielding 8Li whose resulting
decay yields the antineutrinos. In this note, we use FLUKA and GEANT4
simulations to investigate three proposed modifications of this standard
proposal. In the first, the 7Li is replaced with 7Li compounds including a
deuterium moderator. In the second, a gap is placed between the target and the
converter to reduce the neutron bounce-back. Finally, we consider cooling the
converter with liquid nitrogen. We find that these modifications can increase
the antineutrino yield by as much as 50 percent. The first also substantially
reduces the quantity of high purity 7Li which is needed.


title:
Data Suppression Algorithms for Surveillance Applications of Wireless
  Sensor and Actor Networks

abstract:
  This paper introduces algorithms for surveillance applications of wireless
sensor and actor networks (WSANs) that reduce communication cost by suppressing
unnecessary data transfers. The objective of the considered WSAN system is to
capture and eliminate distributed targets in the shortest possible time.
Computational experiments were performed to evaluate effectiveness of the
proposed algorithms. The experimental results show that a considerable
reduction of the communication costs together with a performance improvement of
the WSAN system can be obtained by using the communication algorithms that are
based on spatiotemporal and decision aware suppression methods.


title: Curved branes with regular support

abstract:
  We study spacetime singularities in a general five-dimensional braneworld
with curved branes satisfying four-dimensional maximal symmetry. The bulk is
supported by an analog of perfect fluid with the time replaced by the extra
coordinate. We show that contrary to the existence of finite distance
singularities from the brane location in any solution with flat (Minkowski)
branes, in the case of curved branes there are singularity-free solutions for a
range of equations of state compatible with the null energy condition.


title:
Determination of the neutrino mass hierarchy with a new statistical
  method

abstract:
  Nowadays neutrino physics is undergoing a change of perspective: the
discovery period is almost over and the phase of precise measurements is
starting. Despite the limited statistics collected for some variables, the
three--flavour oscillation neutrino framework is strengthening well. In this
framework a new method has been developed to determine the neutrino mass
ordering, one of the still unknown and most relevant parameters. The method is
applied to the 2015 results of the NOvA experiment for $\nu_\mu \rightarrow
\nu_e$ appearance, including its systematic errors. A substantial gain in
significance is obtained compared to the traditional $\Delta\chi^2$ approach.
Perspectives are provided for future results obtainable by NOvA with larger
exposures. Assuming the number of the 2015 $\nu_e$ observed events scales with
the exposure, an increase in only a factor three would exclude the inverted
hierarchy at more than 95\% C.L. over the full range of the CP violating phase.
The preliminary 2016 NOvA measurement on \numunue appearance has also been
analyzed.


title:
The Guarded Lambda-Calculus: Programming and Reasoning with Guarded
  Recursion for Coinductive Types

abstract:
  We present the guarded lambda-calculus, an extension of the simply typed
lambda-calculus with guarded recursive and coinductive types. The use of
guarded recursive types ensures the productivity of well-typed programs.
Guarded recursive types may be transformed into coinductive types by a
type-former inspired by modal logic and Atkey-McBride clock quantification,
allowing the typing of acausal functions. We give a call-by-name operational
semantics for the calculus, and define adequate denotational semantics in the
topos of trees. The adequacy proof entails that the evaluation of a program
always terminates. We introduce a program logic with L\"ob induction for
reasoning about the contextual equivalence of programs. We demonstrate the
expressiveness of the calculus by showing the definability of solutions to
Rutten's behavioural differential equations.


title: Hadronisation Models and Colour Reconnection

abstract:
  Enhanced production of hadrons with $s$-quark content has been observed in
$pp$ collisions at LHC, and earlier in collisions of heavy nuclei. We review
the string hadronisation formalism and correc- tions from rope hadronisation
and colour reconnection, corrections that takes place in such dense
environments, and are able to correctly describe data. Since such corrections
are very sensitive to the modelling of transverse proton structure, we
investigate two such models, and compare to final states. Finally we describe
how such corrections can also give a possible explanation to collective
phenomena observed in small systems.


title: The sunrise integral and elliptic polylogarithms

abstract:
  We summarize recent computations with a class of elliptic generalizations of
polylogarithms, arising from the massive sunrise integral. For the case of
arbitrary masses we obtain results in two and four space-time dimensions. The
iterated integral structure of our functions allows us to furthermore compute
the equal mass case to arbitrary order.


title: Vote-boosting ensembles

abstract:
  Vote-boosting is a sequential ensemble learning method in which the
individual classifiers are built on different weighted versions of the training
data. To build a new classifier, the weight of each training instance is
determined in terms of the degree of disagreement among the current ensemble
predictions for that instance. For low class-label noise levels, especially
when simple base learners are used, emphasis should be made on instances for
which the disagreement rate is high. When more flexible classifiers are used
and as the noise level increases, the emphasis on these uncertain instances
should be reduced. In fact, at sufficiently high levels of class-label noise,
the focus should be on instances on which the ensemble classifiers agree. The
optimal type of emphasis can be automatically determined using
cross-validation. An extensive empirical analysis using the beta distribution
as emphasis function illustrates that vote-boosting is an effective method to
generate ensembles that are both accurate and robust.


title:
Stride variability measures derived from wrist- and hip-worn
  accelerometers

abstract:
  Many epidemiological and clinical studies use accelerometry to objectively
measure physical activity using the activity counts, vector magnitude, or
number of steps. These measures use just a fraction of the information in the
raw accelerometry data as they are typically summarized at the minute level. To
address this problem we define and estimate two gait measures of temporal
stride-to-stride variability based on raw accelerometry data: Amplitude
Deviation (AD) and Phase Deviation (PD). We explore the sensitivity of our
approach to on-body placement of the accelerometer by comparing hip, left and
right wrist placements. We illustrate the approach by estimating AD and PD in
46 elderly participants in the Developmental Epidemiologic Cohort Study (DECOS)
who worn accelerometers during a 400 meter walk test. We also show that AD and
PD have a statistically significant association with the gait speed and
sit-to-stand test performance


title:
Intrinsic time in Geometrodynamics: introduction and application to
  Friedmann cosmology

abstract:
  An intrinsic local time in Geometrodynamics is obtained with using a scaled
Dirac's mapping. By addition of a background metric, one can construct a scalar
field. It is suitable to play a role of intrinsic time. Cauchy problem was
successfully solved in conformal variables because they are physical ones.
First, the intrinsic time as a logarithm of determinant of spatial metric, was
applied to a cosmological problem by Misner. A global time is exist under
condition of constant mean curvature slicing of spacetime. A volume of
hypersurface and the so-called mean York's time are canonical conjugated pair.
So, the volume is the intrinsic global time by its sense. The experimentally
observed redshift in cosmology is the evidence of its existence. An intrinsic
time of homogeneous models is global. The Friedmann equation by its sense ties
time intervals. Exact solutions of the Friedmann equation in Standard cosmology
with standard and conformal units are presented. Theoretical curves
interpolated the Hubble diagram on latest supernovae are expressed in
analytical form. The class of functions in which the concordance model is
described is Weierstrass meromorphic functions. The Standard cosmological model
is used for fitting the modern Hubble diagram. The physical interpretation of
the modern data from concept of conformal magnitudes is simpler, so is
preferable.


title: Stochastic Dominance Constraints in Elastic Shape Optimization

abstract:
  This paper deals with shape optimization for elastic materials under
stochastic loads. It transfers the paradigm of stochastic dominance, which
allows for flexible risk aversion via comparison with benchmark random
variables, from finite-dimensional stochastic programming to shape
optimization. Rather than handling risk aversion in the objective, this enables
risk aversion by including dominance constraints that single out subsets of
nonanticipative shapes which compare favorably to a chosen stochastic
benchmark. This new class of stochastic shape optimization problems arises by
optimizing over such feasible sets. The analytical description is built on
risk-averse cost measures. The underlying cost functional is of compliance type
plus a perimeter term, in the implementation shapes are represented by a phase
field which permits an easy estimate of a regularized perimeter. The analytical
description and the numerical implementation of dominance constraints are built
on risk-averse measures for the cost functional. A suitable numerical
discretization is obtained using finite elements both for the displacement and
the phase field function. Different numerical experiments demonstrate the
potential of the proposed stochastic shape optimization model and in particular
the impact of high variability of forces or probabilities in the different
realizations.


title: Recent progress in geometric Langlands theory

abstract:
  The is the English version of the text of the talk at S\'eminaire Bourbaki on
February 16, 2016


title: Optimal Locally Repairable Codes with Improved Update Complexity

abstract:
  For a systematic erasure code, update complexity (UC) is defined as the
maximum number of parity blocks needed to be changed when some information
blocks are updated. Locally repairable codes (LRCs) have been recently proposed
and used in real-world distributed storage systems. In this paper, update
complexity for optimal LRC is studied and both lower and upper bounds on UC are
established in terms of length (n), dimension (k), minimum distance (d), and
locality (r) of the code, when (r+1)|n. Furthermore, a class of optimal LRCs
with small UC is proposed. Our proposed LRCs could be of interest as they
improve UC without sacrificing optimality of the code.


title: Frequency-locked chaotic opto-RF oscillator

abstract:
  A driven opto-RF oscillator, consisting of a dual-frequency laser (DFL)
submitted to frequency-shifted feedback, is studied experimentally and
numerically in a chaotic regime. Precise control of the reinjection strength
and detuning permits to isolate a parameter region of bounded-phase chaos,
where the opto-RF oscillator is frequency-locked to the master oscillator, in
spite of chaotic phase and intensity oscillations. Robust experimental evidence
of this synchronization regime is found and phase noise spectra allows to
compare phase-locking and bounded-phase chaos regimes. In particular, it is
found that the long-term phase stability of the master oscillator is well
transferred to the opto-RF oscillator even in the chaotic regime.


title:
The effect of the cosmological constant on gravitational wave quadrupole
  signal

abstract:
  In this study the effects of a non-zero cosmological constant $\Lambda$ on a
quadrupole signal are studied. The linearized approximation of general
relativity was used, so the metric can be written as
$g_{\mu\nu}=\eta_{\mu\nu}+h_{\mu\nu}=\eta_{\mu\nu}+h_{\mu\nu}^{\Lambda}+h_{\mu\nu}^{GW}$
where $h_{\mu\nu}^{GW}$ can be interpreted as gravitational waves and
$h_{\mu\nu}^{\Lambda}$ is the background perturbation. The $\Lambda h^{GW}$
term was also included in this study. To derive physically relevant
consequences of $\Lambda\neq0$, the Friedmann--Robertson--Walker comoving
coordinates are used. In these coordinates, the equations of motion are not
self-consistent so the result of the linearized theory have to be transformed
to the FRW metric. The luminosity distance and the same order of the magnitude
of frequency of the GW150914 was used for the results.


title: Rosseland and flux mean opacities for Compton scattering

abstract:
  Rosseland mean opacity plays an important role in theories of stellar
evolution and X-ray burst models. In the high-temperature regime, when most of
the gas is completely ionized, the opacity is dominated by Compton scattering.
Our aim here is to critically evaluate previous works on this subject and to
compute exact Rosseland mean opacity for Compton scattering in a broad range of
temperatures and electron degeneracy parameter. We use relativistic kinetic
equations for Compton scattering and compute the photon mean free path as a
function of photon energy by solving the corresponding integral equation in the
diffusion limit. As a byproduct we also demonstrate the way to compute photon
redistribution functions in case of degenerate electrons. We then compute the
Rosseland mean opacity as a function of temperature and electron degeneracy. We
compare our results to the previous calculations and find a significant
difference in the low-temperature regime and strong degeneracy. We find useful
analytical expressions that approximate well the numerical results. We then
proceed to compute the flux mean opacity and show that in diffusion
approximation it is nearly identical to the Rosseland mean opacity. We also
provide a simple way for accounting for the true absorption in evaluation of
the Rosseland and flux mean opacities.


title: Symplectic non-squeezing for the cubic NLS on the line

abstract:
  We prove symplectic non-squeezing for the cubic nonlinear Schr\"odinger
equation on the line via finite-dimensional approximation.


title:
Young Massive Clusters: Their Population Properties, Formation and
  Evolution, and Their Relation to the Ancient Globular Clusters

abstract:
  This review summarises the main properties of Young Massive Clusters (YMCs),
including their population properties, particularly focusing on extragalactic
cluster samples. We discuss potential biases and caveats that can affect the
construction of cluster samples and how incompleteness effects can result in
erroneous conclusions regarding the long term survival of clusters. In addition
to the luminosity, mass and age distributions of the clusters, we discuss the
size distribution and profile evolution of the clusters. We also briefly
discuss the stellar populations within YMCs. The final part of the review
focusses on the connections between YMCs and the ancient globular clusters,
whether or not they are related objects and how we can use what we know about
YMC formation and evolution to understand how GCs formed in the early universe
and how they relate to galaxy formation/evolution.


title: Interpreting the 750 GeV diphoton signal as technipion

abstract:
  We discuss whether the enhancement in the diphoton final state at $M_{\gamma
\gamma}$ = 750 GeV, observed recently by the ATLAS and CMS Collaborations could
be a neutral pseudoscalar technipion $\tilde{\pi}^0$. We considered two
distinct minimal models for the dynamical electroweak symmetry breaking. Here
we concentrate only on two-flavor vector-like technicolor model and we assume
that the two-photon fusion is a dominant production mechanism. We include
contributions of $2 \to 1$, $2 \to 2$ and $2 \to 3$ partonic processes. All the
mechanisms give similar contributions to the cross section. With the strong
Yukawa (technipion-techniquark) coupling $g_{TC} \simeq 20$ we roughly obtain
the measured cross section of the "signal". With such value of $g_{TC}$ we get
a relatively small total decay width $\Gamma_{\rm tot}$. We discuss also the
size of the signal at lower energies (LHC, Tevatron) for $\gamma \gamma$ final
states, where the enhancement was not observed. We predict a measurable cross
section for neutral technipion production associated with one or two soft jets.
The technipion signal is compared with the Standard Model diphoton background
contributions. We observe the dominance of inelastic-inelastic $\gamma \gamma$
processes. We predict the signal cross section for purely exclusive $p p \to p
p \gamma \gamma$ procesess at $\sqrt{s}$ = 13 TeV to be about 0.2 fb. Such a
cross section would be, however, difficult to measure with the planned
integrated luminosity. We conclude that in all considered cases the signal is
below the background or/and below the threshold set by statistics although some
tension can be seen.


title:
Programming Patterns in Dataflow Matrix Machines and Generalized
  Recurrent Neural Nets

abstract:
  Dataflow matrix machines arise naturally in the context of synchronous
dataflow programming with linear streams. They can be viewed as a rather
powerful generalization of recurrent neural networks. Similarly to recurrent
neural networks, large classes of dataflow matrix machines are described by
matrices of numbers, and therefore dataflow matrix machines can be synthesized
by computing their matrices. At the same time, the evidence is fairly strong
that dataflow matrix machines have sufficient expressive power to be a
convenient general-purpose programming platform. Because of the network nature
of this platform, programming patterns often correspond to patterns of
connectivity in the generalized recurrent neural networks understood as
programs. This paper explores a variety of such programming patterns.


title:
On the subdifferential of symmetric convex functions of the spectrum for
  symmetric and orthogonally decomposable tensors

abstract:
  The subdifferential of convex functions of the singular spectrum of real
matrices has been widely studied in matrix analysis, optimization and automatic
control theory. Convex optimization over spaces of tensors is now gaining much
interest due to its potential applications in signal processing, statistics and
engineering. The goal of this paper is to present an extension of the approach
by Lewis \cite{lewis1995convex} for the analysis of the subdifferential of
certain convex functions of the spectrum of symmetric tensors. We give a
complete characterization of the subdifferential of Schatten-type tensor norms
for symmetric tensors. Some partial results in this direction are also given
for Orthogonally Decomposable tensors.


title:
Impact of Casimir-Polder interaction on Poisson-spot diffraction at a
  dielectric sphere

abstract:
  Diffraction of matter-waves is an important demonstration of the fact that
objects in nature possess a mixture of particle-like and wave-like properties.
Unlike in the case of light diffraction, matter-waves are subject to a
vacuum-mediated interaction with diffraction obstacles. Here we present a
detailed account of this effect through the calculation of the attractive
Casimir-Polder potential between a dielectric sphere and an atomic beam.
Furthermore, we use our calculated potential to make predictions about the
diffraction patterns to be observed in an ongoing experiment where a beam of
indium atoms is diffracted around a silicon dioxide sphere. The result is an
amplification of the on-axis bright feature which is the matter-wave analogue
of the well-known `Poisson spot' from optics. Our treatment confirms that the
diffraction patterns resulting from our complete account of the sphere
Casimir-Polder potential are indistinguishable from those found via a
large-sphere non-retarded approximation in the discussed experiments,
establishing the latter as an adequate model.


title:
Magnetic-field-induced electric quadrupole moments for relativistic
  hydrogenlike atoms: Application of the Sturmian expansion of the generalized
  Dirac-Coulomb Green function

abstract:
  We consider a Dirac one-electron atom placed in a weak, static, uniform
magnetic field. We show that, to the first order in the strength B of the
external field, the only electric multipole moments, which are induced by the
perturbation in the atom, are those of an even order. Using the Sturmian
expansion of the generalized Dirac-Coulomb Green function [R. Szmytkowski, J.
Phys. B 30, 825 (1997); 30, 2747(E) (1997)], we derive a closed-form expression
for the electric quadrupole moment induced in the atom in an arbitrary discrete
energy eigenstate. The result, which has the form of a double finite sum
involving the generalized hypergeometric functions 3F2 of the unit argument,
agrees with the earlier relativistic formula for that quantity, obtained by us
for the ground state of the atom.


title:
The role of crystallographic orientation of martensitic variants on
  cleavage crack propagation

abstract:
  Cleavage crack propagation has been investigated in a low-carbon
lath-martensitic steel using electron back-scattered diffraction technique. The
ability of different martensitic boundaries within prior-austenite grain, such
as sub-block, block and packet boundaries to resist cleavage crack propagation
has been estimated in terms of Kurdjumov-Sachs crystallographic variants.
Crystallographic study of crack path indicated that block boundaries are more
effective in cleavage crack deviation as compared to packet boundaries, whilst
sub-block boundaries are ineffective in that respect. Moreover, characterizing
the boundaries in terms of misorientation angle (angle-axis pair) may be
misleading if their effectiveness in retarding cleavage crack propagation is
considered.


title:
Dynamic defect correlations dominate activated electronic transport in
  SrTiO3

abstract:
  Strontium titanate (SrTiO3, STO) is a critically important material for the
study of emergent electronic phases in complex oxides, as well as for the
development of applications based on their heterostructures. Despite the large
body of knowledge on STO, there are still many uncertainties regarding the role
of defects in the properties of STO, including their influence on
ferroelectricity in bulk STO and ferromagnetism in STO-based heterostructures.
We present a detailed analysis of the decay of persistent photoconductivity in
STO single crystals with defect concentrations that are relatively low but
significantly affect their electronic properties. The results show that
photo-activated electron transport cannot be described by a superposition of
the properties due to independent point defects as current models suggest but
is, instead, governed by defect complexes that interact through dynamic
correlations. These results emphasize the importance of defect correlations for
activated electronic transport properties of semiconducting and insulating
perovskite oxides.


title: Single-Crystal Growth of a FeCoCrMnAl High-Entropy Alloy

abstract:
  We have grown a single crystal of the equiatomic FeCoCrMnAl high-entropy
alloy. The crystal was grown by means of the Bridgman technique and is about 1
cm in diameter and 6.6 cm in length. X-ray Laue images taken at various
positions on the surface are sharp and mutually consistent, reflecting its
single-crystal nature. We thus report on the first successful growth of a
single crystal of a high-entropy alloy with a volume of the order of cubic
centimeters. The material has a microstructure consisting of B2 inclusions in a
body-centered cubic matrix on the 10 nm length scale.


title: Comparative study of high-Tc superconductivity in H3S and H3P

abstract:
  We report on a comparative study of the electronic structure, phonon spectra,
and superconducting properties for recently discovered superconducting
hydrides, H3S and H3P. While the electronic structures of these two materials
are similar, there are notable changes in the phonon spectra and
electron-phonon coupling. The low-frequency bond-bending modes are softened in
H3P and their coupling to the electrons at the Fermi surface is enhanced
relative to H3S. Nevertheless, coupling to the high-frequency modes is reduced
so the resulting calculated superconducting transition temperature is reduced
from ~166 K in H3S to ~76 K in H3P.


title: Moir\'e superlattices in strained graphene-gold hybrid nanostructures

abstract:
  Graphene-metal nanoparticle hybrid materials potentially display not only the
unique properties of metal nanoparticles and those of graphene, but also
additional novel properties due to the interaction between graphene and
nanoparticles. This study shows that gold nanoislands can be used to tailor the
local electronic properties of graphene. Graphene on crystalline gold
nanoislands exhibits moir\'e superlattices, which generate secondary Dirac
points in the local density of states. Conversely, the graphene covered gold
regions undergo a polycrystalline to Au(111) phase transition upon annealing.
Moreover, the nanoscale coexistence of moir\'e superlattices with different
moir\'e periodicities has also been revealed. Several of these moir\'e
periodicities are anomalously large, which cannot be explained by the standard
lattice mismatch between the graphene and the topmost Au(111) layers. Density
functional theory and molecular dynamics simulations show for the first time
that in such cases the graphene and the interfacial metallic layer is strained,
leading to distorted lattice constants, and consequently to reduced misfit.
Room temperature charge localization induced by a large wavelength moir\'e
pattern is also observed by scanning tunneling spectroscopy. These findings can
open a route towards the strain engineering of graphene/metal interfaces with
various moir\'e superlattices and tailored electronic properties for nanoscale
information coding.


title:
Eikonal model analysis of elastic proton-proton collisions at 52.8 GeV
  and 8 TeV

abstract:
  Under the influence of standardly used description of Coulomb-hadronic
interference proposed by West and Yennie the protons have been interpreted as
transparent objects; elastic events have been interpreted as more central than
inelastic ones. It will be shown that using eikonal model the protons may be
interpreted in agreement with usual ontological conception; elastic processes
being more peripheral than inelastic ones. The corresponding results (differing
fundamentally from the suggested hitherto models) will be presented by
analyzing the most ample elastic data set measured at the ISR energy of 52.8
GeV and the LHC energy of 8 TeV. Detailed analysis of measured differential
cross section will be performed and possibility of peripheral behavior on the
basis of eikonal model will be presented. The impact of recently established
electromagnetic form factors on determination of quantities specifying hadron
interaction determined from the fits of experimental elastic data will be
analyzed. The influence of some other assumptions on proton characteristics
derived from elastic hadronic amplitude determined on the basis of experimental
data will be studied, too.


title: Intermediates and Generic Convergence to Equilibria

abstract:
  Known graphical conditions for the generic or global convergence to
equilibria of the dynamical system arising from a reaction network are shown to
be invariant under the so-called successive removal of intermediates, a
systematic procedure to simplify the network, making the graphical conditions
easier to check.