title:
Global Boundedness of the Gradient for a Class of Schr\"odinger
  Equations

abstract:
  In this paper, via applying the method developed by A. Cianchi and V. Maz'ya,
the author obtains the global boundedness of the gradient for solutions to
Dirichlet and Neumann problems of a class of Schr\"odinger equations under the
minimal assumptions for integrability on the data and regularity on the
boundary of the domain. Moreover, the case of arbitrary bounded semi-convex
domains is also considered.


title:
Thermodynamic evidence for nematic superconductivity in
  Cu$_x$Bi$_2$Se$_3$

abstract:
  Unconventional superconductivity is characterized by the spontaneous symmetry
breaking of the macroscopic superconducting wavefunction in addition to the
gauge symmetry breaking, such as rotational-symmetry breaking with respect to
the underlying crystal-lattice symmetry. Particularly, superconductivity with
spontaneous rotational-symmetry breaking in the wavefunction amplitude and thus
in bulk properties, not yet reported previously, is intriguing and can be
termed "nematic" superconductivity in analogy to nematic liquid-crystal phases.
Here, based on specific-heat measurements of the single-crystalline
Cu$_x$Bi$_2$Se$_3$ under accurate magnetic-field-direction control, we report
thermodynamic evidence for nematic superconductivity, namely, clear
two-fold-symmetric behavior in a trigonal lattice. The results indicate
realization of an "odd-parity nematic" state, feasible only by macroscopic
quantum condensates and distinct from nematic states in liquid crystals. The
results also confirm topologically non-trivial superconductivity in
Cu$_x$Bi$_2$Se$_3$.

categories: cond-mat.supr-con cond-mat.mtrl-sci cond-mat.soft cond-mat.str-el


title: Survival of pure disk galaxies over the last 8 billion years

abstract:
  Pure disk galaxies without any bulge component, i.e., neither classical nor
pseudo, seem to have escaped the affects of merger activity inherent to
hierarchical galaxy formation models as well as strong internal secular
evolution.
  We discover that a significant fraction (15 - 18 %) of disk galaxies in the
Hubble Deep Field (0.4 < z < 1.0) as well as in the local Universe (0.02 < z <
0.05) are such pure disk systems (hereafter, PDS). The spatial distribution of
light in these PDS is well described by a single exponential function from the
outskirts to the centre and appears to have remained intact over the last 8
billion years keeping the mean central surface brightness and scale-length
nearly constant. These two disk parameters of PDS are brighter and shorter,
respectively, than of those disks which are part of disk galaxies with bulges.
  Since the fraction of PDS as well as their profile defining parameters do not
change, it indicates that these galaxies have not witnessed either major
mergers or multiple minor mergers since z~1. However, there is substantial
increase in their total stellar mass and total size over the same time range.
This suggests that smooth accretion of cold gas via cosmic filaments is the
most probable mode of their evolution. We speculate that PDS are dynamically
hotter and cushioned in massive dark matter halos which may prevent them from
undergoing strong secular evolution.


title:
Multilevel Monte Carlo analysis for optimal control of elliptic PDEs
  with random coefficients

abstract:
  This work is motivated by the need to study the impact of data uncertainties
and material imperfections on the solution to optimal control problems
constrained by partial differential equations. We consider a pathwise optimal
control problem constrained by a diffusion equation with random coefficient
together with box constraints for the control. For each realization of the
diffusion coefficient we solve an optimal control problem using the variational
discretization [M. Hinze, Comput. Optim. Appl., 30 (2005), pp. 45-61]. Our
framework allows for lognormal coefficients whose realizations are not
uniformly bounded away from zero and infinity. We establish finite element
error bounds for the pathwise optimal controls. This analysis is nontrivial due
to the limited spatial regularity and the lack of uniform ellipticity and
boundedness of the diffusion operator. We apply the error bounds to prove
convergence of a multilevel Monte Carlo estimator for the expected value of the
pathwise optimal controls. In addition we analyze the computational complexity
of the multilevel estimator. We perform numerical experiments in 2D space to
confirm the convergence result and the complexity bound.


title:
Direct measurement of excited-state dipole matrix elements using
  electromagnetically induced transparency in the hyperfine Paschen-Back regime

abstract:
  Applying large magnetic fields to gain access to the hyperfine Paschen-Back
regime can isolate three-level systems in a hot alkali metal vapors, thereby
simplifying usually complex atom-light interactions. We use this method to make
the first direct measurement of the $\vert\langle 5P\vert\vert er\vert\vert
5D\rangle\vert$ matrix element in $^{87}$Rb. An analytic model with only three
levels accurately models the experimental electromagnetically induced
transparency spectra and extracted Rabi frequencies are used to determine the
dipole matrix element. We measure $\vert\langle 5P_{3/2}\vert\vert er\vert\vert
5D_{5/2}\rangle\vert = (2.290\pm0.002_{\rm stat}\pm0.04_{\rm syst})~ea_{0}$
which is in excellent agreement with the theoretical calculations of Safronova,
Williams, and Clark [Phys. Rev. A \textbf{69}, 022509 (2004)].


title: Easily doped p-type, low hole effective mass, transparent oxides

abstract:
  Fulfillment of the promise of transparent electronics has been hindered until
now largely by the lack of semiconductors that can be doped p-type in a stable
way, and that at the same time present high hole mobility and are highly
transparent in the visible spectrum. Here, a high-throughput study based on
first-principles methods reveals four oxides, namely X2SeO2, with X = La, Pr,
Nd, and Gd, which are unique in that they exhibit excellent characteristics for
transparent electronic device applications-i.e., a direct band gap larger than
3.1 eV, an average hole effective mass below the electron rest mass, and good
p-type dopability. Furthermore, for La2SeO2 it is explicitly shown that Na
impurities substituting La are shallow acceptors in moderate to strong
anion-rich growth conditions, with low formation energy, and that they will not
be compensated by anion vacancies VO or VSe.


title: Detecting chirality in molecules by linearly polarized laser fields

abstract:
  A new scheme for enantiomer differentiation of chiral molecules using a pair
of linearly polarized intense ultrashort laser pulses with skewed mutual
polarization is presented. The technique relies on the fact that the
off-diagonal anisotropic contributions to the electric polarizability tensor
for two enantiomers have different signs. Exploiting this property, we are able
to excite a coherent unidirectional rotation of two enantiomers with a {\pi}
phase difference in the molecular electric dipole moment. The approach is
robust and suitable for relatively high temperatures of molecular samples,
making it applicable for selective chiral analysis of mixtures, and to chiral
molecules with low barriers between enantiomers. As an illustration, we present
nanosecond laser-driven dynamics of a tetratomic non-rigid chiral molecule with
short-lived chirality. The ultrafast time scale of the proposed technique is
well suited to study parity violation in molecular systems in short-lived
chiral states.


title: To make a glass - avoid the crystal

abstract:
  Colloidal model systems allow for a flexible tuning of particle sizes,
particle spacings and mutual interactions at constant temperature. Colloidal
suspensions typically crystallize as soon as the interactions get sufficiently
strong and long-ranged. Several strategies have been successfully applied to
avoid crystallization and instead produce colloidal glasses. Most of these
amorphous solids are formed at high particle concentrations. This paper shortly
reviews experimental attempts to produce amorphous colloidal solids using
strategies based on topological, thermodynamic and kinetic considerations. We
complement this overview by introducing a (transient) amorphous solid forming
in a thoroughly deionized aqueous suspension of highly charged spheres at low
salt concentration and very low volume fractions.


title:
Majority-vote model on spatially embedded networks: crossover from
  mean-field to Ising universality classes

abstract:
  We study through Monte Carlo simulations and finite-size scaling analysis the
nonequilibrium phase transitions of the majority-vote model taking place on
spatially embedded networks. These structures are built from an underlying
regular lattice over which long-range connections are randomly added according
to the probability, $P_{ij}\sim{r^{-\alpha}}$, where $r_{ij}$ is the Manhattan
distance between nodes $i$ and $j$, and the exponent $\alpha$ is a controlling
parameter [J. M. Kleinberg, Nature 406, 845 (2000)]. Our results show that the
collective behavior of this system exhibits a continuous order-disorder phase
transition at a critical parameter, which is a decreasing function of the
exponent $\alpha$. Precisely, considering the scaling functions and the
critical exponents calculated, we conclude that the system undergoes a
crossover among distinct universality classes. For $\alpha\le3$ the critical
behavior is described by mean-field exponents, while for $\alpha\ge4$ it
belongs to the Ising universality class. Finally, in the region where the
crossover occurs, $3<\alpha<4$, the critical exponents are dependent on
$\alpha$.


title: Inflation in pure gravity with only massless spin-2 fields

abstract:
  We show that without introducing additional fields or extra degrees of
freedom, a specific higher derivative extension of Einstein's gravity that has
only a massless spin-2 excitation in its perturbative spectrum, has an
inflationary period, a quasi-de Sitter phase with enough number of e-foldings
required to solve the horizon and related problems. The crucial ingredient in
the construction is the curvature dependence of the effective Newton's
constant.


title:
Spin-charge-entangled non-Fermi liquid in a candidate material for a
  doped spin liquid

abstract:
  Quantum spin liquids are exotic Mott insulators that carry extraordinary spin
excitations and thus, when doped, expected to afford novel metallic states
coupled to the unconventional magnetic excitations. The organic
triangular-lattice system k-(ET)4Hg2.89Br8 is a promising candidate for the
doped spin-liquid and hosts a non-Fermi liquid at low pressures. We show that,
in the non-Fermi liquid regime, the charge transport confined in the layer gets
deconfined sharply at low temperatures, coinciding with the entrance of spins
into a quantum regime as signified by a steep decrease in spin susceptibility
behaving like the triangular-lattice Heisenberg model indicative of spin-charge
separation at high temperatures. This suggests a new type of non-Fermi liquid,
where interlayer charge-deconfimement is associated with spin-charge
entanglement.


title:
A High-Performance Mid-infrared Optical Switch Enabled by Bulk Dirac
  Fermions in Cd3As2

abstract:
  Pulsed lasers operating in the 2-5 {\mu}m band are important for a wide range
of applications in sensing, spectroscopy, imaging and communications. Despite
recent advances with mid-infrared gain media, the lack of a capable pulse
generation mechanism, i.e. a passive optical switch, remains a significant
technological challenge. Here we show that mid-infrared optical response of
Dirac states in crystalline Cd3As2, a three-dimensional topological Dirac
semimetal (TDS), constitutes an ideal ultrafast optical switching mechanism for
the 2-5 {\mu}m range. Significantly, fundamental aspects of the photocarrier
processes, such as relaxation time scales, are found to be flexibly controlled
through element doping, a feature crucial for the development of convenient
mid-infrared ultrafast sources. Although various exotic physical phenomena have
been uncovered in three-dimensional TDS systems, our findings show for the
first time that this emerging class of quantum materials can be harnessed to
fill a long known gap in the field of photonics.


title:
Representation of linguistic form and function in recurrent neural
  networks

abstract:
  We present novel methods for analyzing the activation patterns of RNNs from a
linguistic point of view and explore the types of linguistic structure they
learn. As a case study, we use a multi-task gated recurrent network
architecture consisting of two parallel pathways with shared word embeddings
trained on predicting the representations of the visual scene corresponding to
an input sentence, and predicting the next word in the same sentence. Based on
our proposed method to estimate the amount of contribution of individual tokens
in the input to the final prediction of the networks we show that the image
prediction pathway: a) is sensitive to the information structure of the
sentence b) pays selective attention to lexical categories and grammatical
functions that carry semantic information c) learns to treat the same input
token differently depending on its grammatical functions in the sentence. In
contrast the language model is comparatively more sensitive to words with a
syntactic function. Furthermore, we propose methods to ex- plore the function
of individual hidden units in RNNs and show that the two pathways of the
architecture in our case study contain specialized units tuned to patterns
informative for the task, some of which can carry activations to later time
steps to encode long-term dependencies.


title:
On the Hyperbolicity Properties of Inertial Manifolds of
  Reaction--Diffusion Equations

abstract:
  For 3D reaction--diffusion equations, we study the problem of existence or
nonexistence of an inertial manifold that is normally hyperbolic or absolutely
normally hyperbolic. We present a system of two coupled equations with a cubic
nonlinearity which does not admit a normally hyperbolic inertial manifold. An
example separating the classes of such equations admitting an inertial manifold
and a normally hyperbolic inertial manifold is constructed. Similar questions
concerning absolutely normally hyperbolic inertial manifolds are discussed.


title: Completeness and the ZX-calculus

abstract:
  Graphical languages offer intuitive and rigorous formalisms for quantum
physics. They can be used to simplify expressions, derive equalities, and do
computations. Yet in order to replace conventional formalisms, rigour alone is
not sufficient: the new formalisms also need to have equivalent deductive
power. This requirement is captured by the property of completeness, which
means that any equality that can be derived using some standard formalism can
also be derived graphically.
  In this thesis, I consider the ZX-calculus, a graphical language for pure
state qubit quantum mechanics. I show that it is complete for pure state
stabilizer quantum mechanics, so any problem within this fragment of quantum
theory can be fully analysed using graphical methods. This includes questions
of central importance in areas such as error-correcting codes or
measurement-based quantum computation. Furthermore, I show that the ZX-calculus
is complete for the single-qubit Clifford+T group, which is approximately
universal: any single-qubit unitary can be approximated to arbitrary accuracy
using only Clifford gates and the T-gate. [...] Lastly, I extend the use of
rigorous graphical languages outside quantum theory to Spekkens' toy theory, a
local hidden variable model that nevertheless exhibits some features commonly
associated with quantum mechanics. [...] I develop a graphical calculus similar
to the ZX-calculus that fully describes Spekkens' toy theory, and show that it
is complete. Hence, stabilizer quantum mechanics and Spekkens' toy theory can
be fully analysed and compared using graphical formalisms.
  Intuitive graphical languages can replace conventional formalisms for the
analysis of many questions in quantum computation and foundations without loss
of mathematical rigour or deductive power.


title: Dipole oscillation modes in light $\alpha$-clustering nuclei

abstract:
  The $\alpha$ cluster states are discussed in a model frame of extended
quantum molecular dynamics. Different alpha cluster structures are studied in
details, such as $^8$Be two-$\alpha$ cluster structure, $^{12}$C triangle
structure, $^{12}$C chain structure, $^{16}$O chain structure, $^{16}$O kite
structure, and $^{16}$O square structure. The properties studied, include as
the width of wave packets for different $\alpha$ clusters, momentum
distribution, and the binding energy among $\alpha$ clusters. It is also
discussed how the $\alpha$ cluster degree of freedom affects nuclear collective
vibrations. The cluster configurations in $^{12}$C and $^{16}$O are found to
have corresponding characteristic spectra of giant dipole resonance (GDR), and
the coherences of different $\alpha$ clusters's dipole oscillation are
described in details. The geometrical and dynamical symmetries of
$\alpha$-clustering configurations are responsible for the number and centroid
energies of peaks of GDR spectra. Therefore, the GDR can be regarded as an
effective probe to diagnose different $\alpha$ cluster configurations in light
nuclei.


title:
Multi-Material 3-D Viscoelastic Model of a Transtibial Residuum from
  In-vivo Indentation and MRI Data

abstract:
  Although the socket is critical in a prosthetic system for a person with limb
amputation, the methods of its design are largely artisanal. A roadblock for a
repeatable and quantitative socket design process is the lack of predictive and
patient specific biomechanical models of the residuum. This study presents the
evaluation of such a model using a combined experimental-numerical approach.
The model geometry and tissue boundaries are derived from MRI. The soft tissue
non-linear elastic and viscoelastic mechanical behavior was evaluated using
inverse finite element analysis (FEA) of in-vivo indentation experiments. A
custom designed robotic in-vivo indentation system was used to provide a rich
experimental data set of force versus time at 18 sites across a limb. During
FEA, the tissues were represented by two layers, namely the skin-adipose layer
and an underlying muscle-soft tissue complex. The non-linear elastic behavior
was modeled using 2nd order Ogden hyperelastic formulations, and
viscoelasticity was modeled using the quasi-linear theory of viscoelasticity.
To determine the material parameters for each tissue, an inverse FEA based
optimization routine was used that minimizes the combined mean of the squared
force differences between the numerical and experimental force-time curves for
indentations at 4 distinct anatomical regions on the residuum. The optimization
provided the following material parameters for the skin-adipose layer: c=5.22
kPa, m=4.79, gamma=3.57 MPa, tau=0.32 s and for the muscle-soft tissue complex:
c=5.20 kPa, m=4.78, gamma=3.47 MPa, tau=0.34 s. These parameters were evaluated
to predict the force-time curves for the remaining 14 anatomical locations. The
mean percentage error (mean absolute error/ maximum experimental force) for
these predictions was 7 +/- 3%. The mean percentage error at the 4 sites used
for the optimization was 4%.


title:
Failure of classical traffic and transportation theory: The maximization
  of the network throughput maintaining free flow conditions in network

abstract:
  We have revealed general physical conditions for the {\it maximization} of
the network throughput at which free flow conditions are ensured, i.e., traffic
breakdown cannot occur in the whole traffic or transportation network. A
physical measure of the network -- {\it network capacity} is introduced that
characterizes general features of the network with respect to the maximization
of the network throughput. The network capacity allows us also to make a
general proof of the deterioration of traffic system occurring when dynamic
traffic assignment is performed in a network based on the classical Wardrop'
user equilibrium (UE) and system optimum (SO) equilibrium.


title: A Generic Slice of the Moduli Space of Line Arrangements

abstract:
  We study the compactification of the locus parametrizing lines with a fixed
intersection to a given line, inside the moduli space of line arrangements in
the projective plane constructed for weight one by Hacking-Keel-Tevelev and
Alexeev for general weights. We show that this space is smooth, with normal
crossing boundary, and that it has a morphism to the moduli space of marked
rational curves which can be understood as a natural continuation of the blow
up construction of Kapranov. In addition, we prove that it is isomorphic to a
closed subvariety inside a non-reductive Chow quotient. The parametrized
objects are surfaces with broken lines, whose dual graphs are rooted trees with
possibly repeated markings.


title: Anisotropic thermal expansion of bismuth from first principles

abstract:
  Some anisotropy in both mechanical and thermodynamical properties of bismuth
is expected. A combination of density functional theory total energy
calculations and density functional perturbation theory in the local density
approximation is used to compute the elastic constants at 0 K using a finite
strain approach and the thermal expansion tensor in the quasiharmonic
approximation. The overall agreement with experiment is good. Furthermore, the
anisotropy in the thermal expansion is found to arise from the anisotropy in
both the directional compressibilities and the directional Gr\"uneisen
functions.


title:
FALDOI: A new minimization strategy for large displacement variational
  optical flow

abstract:
  We propose a large displacement optical flow method that introduces a new
strategy to compute a good local minimum of any optical flow energy functional.
The method requires a given set of discrete matches, which can be extremely
sparse, and an energy functional which locally guides the interpolation from
those matches. In particular, the matches are used to guide a structured
coordinate-descent of the energy functional around these keypoints. It results
in a two-step minimization method at the finest scale which is very robust to
the inevitable outliers of the sparse matcher and able to capture large
displacements of small objects. Its benefits over other variational methods
that also rely on a set of sparse matches are its robustness against very few
matches, high levels of noise and outliers. We validate our proposal using
several optical flow variational models. The results consistently outperform
the coarse-to-fine approaches and achieve good qualitative and quantitative
performance on the standard optical flow benchmarks.


title: Three methods for two-sided bounds of eigenvalues - a comparison

abstract:
  We compare three finite element based methods designed for two-sided bounds
of eigenvalues of symmetric elliptic second order operators. The first method
is known as the Lehmann-Goerisch method. The second method is based on
Crouzeix-Raviart nonconforming finite element method. The third one is a
combination of generalized Weinstein and Kato bounds with complementarity based
estimators. We concisely describe these methods and use them to solve three
numerical examples. We compare their accuracy, computational performance, and
generality in both the lowest and higher order case.


title: Efficiency of inefficient endoreversible thermal machines

abstract:
  We present a study of the performance of endoreversible thermal machines
optimized with respect to the thermodynamic force associated with the cold bath
in the regime of small thermodynamic forces. These thermal machines can work
either as an engine or as a refrigerator. We analyze how the optimal
performances are determined by the dependence of the thermodynamic flux on the
forces. The results are motivated and illustrated with a quantum model, the
three level maser, and explicit analytical expressions of the engine efficiency
as a function of the system parameters are given.


title:
Extensions and the weak Calkin algebra of Read's Banach space admitting
  discontinuous derivations

abstract:
  Read produced the first example of a Banach space $E_{\text{R}}$ such that
the associated Banach algebra $\mathscr{B}(E_{\text{R}})$ of bounded operators
admits a discontinuous derivation (J. London Math. Soc. 1989). We generalise
Read's main theorem about $\mathscr{B}(E_{\text{R}})$ from which he deduced
this conclusion, as well as the key technical lemmas that his proof relied on,
by constructing a strongly split-exact sequence {0} -->
$\mathscr{W}(E_{\text{R}})$ --> $\mathscr{B}(E_{\text{R}})$-->
$\tilde{\ell_2}$-->{0}, where $\mathscr{W}(E_{\text{R}})$ denotes the ideal of
weakly compact operators on $E_{\text{R}}$, while $\tilde{\ell_2}$ is the
unitization of the Hilbert space $\ell_2$, endowed with the zero product.


title: Towards joint reconstruction of noise and losses in quantum channels

abstract:
  The calibration of a quantum channel, i.e. the determination of the
transmission losses affecting it, is definitely one of the principal objectives
in both the quantum communication and quantum metrology frameworks. Another
task of the utmost relevance is the identification, e.g. by extracting its
photon number distribution, of the noise potentially present in the channel.
Here we present a protocol, based on the response of a photon-number-resolving
detector at different quantum efficiencies, able to accomplish both of these
tasks at once, providing with a single measurement an estimate of the
transmission losses as well as the photon statistics of the noise present in
the exploited quantum channel. We show and discuss the experimental results
obtained in the practical implementation of such protocol, with different kinds
and levels of noise.


title: On 132-representable Graphs

abstract:
  A graph $G = (V,E)$ is word-representable if there exists a word $w$ over the
alphabet $V$ such that letters $x$ and $y$ alternate in $w$ if and only if $xy$
is an edge in $E$. Word-representable graphs are the subject of a long research
line in the literature initiated in \cite{KP}, and they are the main focus in
the recently published book \cite{KL}. A word $w=w_1\cdots w_{n}$ avoids the
pattern $132$ if there are no $1\leq i_1<i_2<i_3\leq n$ such that
$w_{i_1}<w_{i_3}<w_{i_2}$. The theory of patterns in words and permutations is
a fast growing area discussed in \cite{HM,Kit}.
  A research direction suggested in \cite{KL} is in merging the theories of
word-representable graphs and patterns in words. Namely, given a class of
pattern-avoiding words, can we describe the class of graphs represented by the
words? Our paper provides the first non-trivial results in this direction. We
say that a graph is 132-representable if it can be represented by a
132-avoiding word. We show that each 132-representable graph is necessarily a
circle graph. Also, we show that any tree and any cycle graph are
132-representable, which is a rather surprising fact taking into account that
most of these graphs are non-representable in the sense specified, as a
generalization of the notion of a word-representable graph, in \cite{JKPR}.
Finally, we provide explicit 132-avoiding representations for all graphs on at
most five vertices, and also describe all such representations, and enumerate
them, for complete graphs.


title:
3D simulations of the electrothermal and THz emission properties of
  Bi$_2$Sr$_2$CaCu$_2$O$_8$ intrinsic Josephson junction stacks

abstract:
  We used 2D coupled sine-Gordon equations combined with 3D heat diffusion
equations to numerically investigate the thermal and electromagnetic properties
of a $250 \times 70\,\mu\mathrm{m}^2$ intrinsic Josephson junction stack. The
700 junctions are grouped to 20 segments; we assume that in a segment all
junctions behave identically. At large input power a hot spot forms in the
stack. Resonant electromagnetic modes, oscillating either along the length ((0,
$n$) modes) or the width (($m$, 0) modes) of the stack or having a more complex
structure, can be excited both with and without a hot spot. At fixed bath
temperature and bias current several cavity modes can coexist in the absence of
a magnetic field. The (1, 0) mode, considered to be the most favorable mode for
THz emission, can be stabilized by applying a small magnetic field along the
length of the stack. A strong field-induced enhancement of the emission power
is also found in experiment, for an applied field around 5.9 mT.


title:
$\Delta(1232)$ resonance in the $\vec{\gamma}p\rightarrow p\pi^0$
  reaction at threshold

abstract:
  We calculate the neutral pion photoproduction on the proton near threshold in
covariant baryon chiral perturbation theory, including the $\Delta(1232)$
resonance as an explicit degree of freedom, up to chiral order $p^{7/2}$ in the
$\delta$ counting. We compare our results with recent low-energy data from the
Mainz Microtron for angular distributions and photon asymmetries. The
convergence of the chiral series of the covariant approach is found to improve
substantially with the inclusion of the $\Delta(1232)$ resonance.


title: Killing tensors in stationary and axially symmetric space-times

abstract:
  We discuss the existence of Killing tensors for certain (physically
motivated) stationary and axially symmetric vacuum space-times. We show
nonexistence of a nontrivial Killing tensor for a Tomimatsu-Sato metric (up to
valence 7), for a C-metric (up to valence 9) and for a Zipoy-Voorhees metric
(up to valence 11). The results are obtained by mathematically completely
rigorous, nontrivial computer algebra computations with a huge number of
equations involved in the problem.


title:
Effect of magnetized phonons on electrical and thermal conductivity of
  neutron star crust

abstract:
  We study electrical and thermal conductivities of degenerate electrons
emitting and absorbing phonons in a strongly magnetized crystalline neutron
star crust. We take into account modification of the phonon spectrum of a
Coulomb solid of ions caused by a strong magnetic field. Boltzmann transport
equation is solved using a generalized variational method. The ensuing
three-dimensional integrals over the transferred momenta are evaluated by two
different numerical techniques, the Monte-Carlo method and a regular
integration over the first Brillouin zone. The results of the two numerical
approaches are shown to be in a good agreement. An appreciable growth of
electrical and thermal resistivities is reported at quantum and intermediate
temperatures $T \lesssim 0.1 T_{\rm p}$ ($T_{\rm p}$ is the ion plasma
temperature) in a wide range of chemical compositions and mass densities of
matter even for moderately magnetized crystals $\omega_{\rm B} \sim \omega_{\rm
p}$ ($\omega_{\rm B}$ and $\omega_{\rm p}$ are the ion cyclotron and plasma
frequencies). This effect is due to an appearance of a soft ($\omega \propto
k^2$) phonon mode in the magnetized ion Coulomb crystal, which turns out to be
easier to excite than acoustic phonons characteristic of the field-free case.
These results are important for modelling magneto-thermal evolution of neutron
stars.


title: Status and prospects for BSM ( (N)MSSM) Higgs searches at the LHC

abstract:
  Searches for Beyond the Standard Model Higgs processes in the context of
Minimal Supersymmetric Standard Model and Next to MSSM are presented. The
results are based on the first LHC run of pp collision data recorded by the
ATLAS and CMS experiments at the CERN Large Hadron Collider at centre-of-mass
energies of 7 and 8 TeV, corresponding to integrated luminosities of about 5
and 20 fb$^{-1}$ respectively. Current searches constrain large parts of the
parameter space. No evidence for BSM Higgs is found.


title: Alternating Set Quantifiers in Modal Logic

abstract:
  We establish the strictness of several set quantifier alternation hierarchies
that are based on modal logic, evaluated on various classes of finite graphs.
This extends to the modal setting a celebrated result of Matz, Schweikardt and
Thomas (2002), which states that the analogous hierarchy of monadic
second-order logic is strict.
  Thereby, the present paper settles a question raised by van Benthem (1983),
revived by ten Cate (2006), and partially answered by Kuusisto (2008, 2015).


title: The new scattering mode emerging at the LHC?

abstract:
  We point out the several experimental manifestations of the new reflective
scattering mode in elastic scattering and multiparticle production at the LHC
energy range.


title:
Generating and protecting correlated quantum states under collective
  dephasing

abstract:
  We study the collective dephasing process of a system of non-interacting
atomic qubits, immersed in a spatially uniform magnetic field of fluctuating
intensity. The correlation properties of bipartite states are analysed based on
a geometric representation of the state space. Particular emphasis is put on
the dephasing-assisted generation of states with a high correlation rank, which
can be related to discord-type correlations and allow for direct applications
in quantum information theory. Finally we study the conditions that ensure the
robustness of initial entanglement and discuss the phenomenon of time-invariant
entanglement.


title: Statistical models for dynamics in extreme value processes

abstract:
  We study four different approaches to model time-dependent extremal behavior:
dynamics introduced by (a) a state-space model (SSM), (b) a shot-noise-type
process with GPD marginals, (c) a copula-based autoregressive model with GPD
marginals, and (d) a GLM with GPD marginals (and previous extremal events as
regressors). Each of the models is fit against data, and from the fitted data,
we simulate corresponding paths according to the respective fitted models. At
this simulated data, the respective dependence structure is analyzed in copula
plots and judged against its capacity to fit the corresponding inter-arrival
distribution.


title: Overshooting and $L^1$-Norms of a Class of Nyquist Filters

abstract:
  To tightly control the signal envelope, estimating the peak regrowth between
FFT samples is an important sub-problem in multicarrier communications. While
the problem is well-investigated for trigonometric polynomials (i.e. OFDM), the
impact of an aperiodic transmit filter is important too and typically neglected
in the peak regrowth analysis. In this paper, we provide new bounds on the
overshooting between samples for general multicarrier signals improving on
available bounds for small oversampling factors. In particular, we generalize a
result of [1, Theorem 4.10]. Our results will be extended to bound overshooting
of a class of Nyquist filters as well. Eventually, results are related to some
respective $L^1$-properties of these filters with application to filter design.


title: Active Curved Polymers form Vortex Patterns on Membranes

abstract:
  Recent in vitro experiments with FtsZ polymers show self-organization into
different dynamic patterns, including structures reminiscent of the bacterial
Z-ring. We model FtsZ polymers as active particles moving along chiral,
circular paths by Brownian dynamics simulations and a Boltzmann approach. Our
two conceptually different methods point to a generic phase behavior. At
intermediate particle densities, we find self-organization into vortex
structures including closed rings. Moreover, we show that the dynamics at the
onset of pattern formation is described by a generalized complex
Ginzburg-Landau equation.


title: Clustering Based Feature Learning on Variable Stars

abstract:
  The success of automatic classification of variable stars strongly depends on
the lightcurve representation. Usually, lightcurves are represented as a vector
of many statistical descriptors designed by astronomers called features. These
descriptors commonly demand significant computational power to calculate,
require substantial research effort to develop and do not guarantee good
performance on the final classification task. Today, lightcurve representation
is not entirely automatic; algorithms that extract lightcurve features are
designed by humans and must be manually tuned up for every survey. The vast
amounts of data that will be generated in future surveys like LSST mean
astronomers must develop analysis pipelines that are both scalable and
automated. Recently, substantial efforts have been made in the machine learning
community to develop methods that prescind from expert-designed and manually
tuned features for features that are automatically learned from data. In this
work we present what is, to our knowledge, the first unsupervised feature
learning algorithm designed for variable stars. Our method first extracts a
large number of lightcurve subsequences from a given set of photometric data,
which are then clustered to find common local patterns in the time series.
Representatives of these patterns, called exemplars, are then used to transform
lightcurves of a labeled set into a new representation that can then be used to
train an automatic classifier. The proposed algorithm learns the features from
both labeled and unlabeled lightcurves, overcoming the bias generated when the
learning process is done only with labeled data. We test our method on MACHO
and OGLE datasets; the results show that the classification performance we
achieve is as good and in some cases better than the performance achieved using
traditional features, while the computational cost is significantly lower.


title: Epidemiological geographic profiling for a meta-population network

abstract:
  Epidemiological geographic profiling is a statistical method for making
inferences about likely areas of a source from the geographical distribution of
patients. Epidemiological geographic profiling algorithms are developed to
locate a source from the dataset on the number of new cases for a
meta-population network model. It is found from the WHO dataset on the SARS
outbreak that Hong Kong remains the most likely source throughout the period of
observation. This reasoning is pertinent under the restricted circumstance that
the number of reported probable cases in China was missing, unreliable, and
incomprehensive. It may also imply that globally connected Hong Kong was more
influential as a spreader than China. Singapore, Taiwan, Canada, and the United
States follow Hong Kong in the likeliness ranking list.


title: A fuzzy based conceptual framework for career counselling

abstract:
  Career guidance for students, particularly in rural areas is a challenging
issue in India. In the present era of digitalization, there is a need of an
automated system that can analyze a student for his/her capabilities, suggest a
career and provide related information. Keeping in mind the requirement, the
present paper is an effort in this direction. In this paper, a fuzzy based
conceptual framework has been suggested. It has two parts; in the first part a
students will be analyzed for his/her capabilities and in the second part the
available courses, job aspects related to their capabilities will be suggested.
To analyze a student, marks in various subject in 10+2 standards and vocational
interest in different fields have been considered and fuzzy sets have been
formed. On example basis, fuzzy inference rules have been framed for analyzing
the abilities in engineering, medical and hospitality fields only. In second
part, concept of composition of relations has been used to suggest the related
courses and jobs.


title:
Measurement of event-shape observables in $Z \to \ell^{+} \ell^{-}$
  events in $pp$ collisions at $\sqrt{s}=7$ TeV with the ATLAS detector at the
  LHC

abstract:
  Event-shape observables measured using charged particles in inclusive
$Z$-boson events are presented, using the electron and muon decay modes of the
$Z$ bosons. The measurements are based on an integrated luminosity of $1.1 {\rm
fb}^{-1}$ of proton--proton collisions recorded by the ATLAS detector at the
LHC at a centre-of-mass energy $\sqrt{s}=7$ TeV. Charged-particle
distributions, excluding the lepton--antilepton pair from the $Z$-boson decay,
are measured in different ranges of transverse momentum of the $Z$ boson.
Distributions include multiplicity, scalar sum of transverse momenta, beam
thrust, transverse thrust, spherocity, and $\mathcal{F}$-parameter, which are
in particular sensitive to properties of the underlying event at small values
of the $Z$-boson transverse momentum. The Sherpa event generator shows larger
deviations from the measured observables than Pythia8 and Herwig7. Typically,
all three Monte Carlo generators provide predictions that are in better
agreement with the data at high $Z$-boson transverse momenta than at low
$Z$-boson transverse momenta and for the observables that are less sensitive to
the number of charged particles in the event.


title:
Characterizing classes of regular languages using prefix codes of
  bounded synchronization delay

abstract:
  In this paper we continue a classical work of Sch\"utzenberger on codes with
bounded synchronization delay. He was interested to characterize those regular
languages where the groups in the syntactic monoid belong to a variety $H$. He
allowed operations on the language side which are union, intersection,
concatenation and modified Kleene-star involving a mapping of a prefix code of
bounded synchronization delay to a group $G\in H$, but no complementation. In
our notation this leads to the language classes $SD_G(A^\infty)$ and
$SD_H(A^\infty$). Our main result shows that $SD_H(A^\infty)$ always
corresponds to the languages having syntactic monoids where all subgroups are
in $H$. Sch\"utzenberger showed this for a variety $H$ if $H$ contains Abelian
groups, only. Our method shows the general result for all $H$ directly on
finite and infinite words. Furthermore, we introduce the notion of local Rees
products which refers to a simple type of classical Rees extensions. We give a
decomposition of a monoid in terms of its groups and local Rees products. This
gives a somewhat similar, but simpler decomposition than in Rhodes' synthesis
theorem. Moreover, we need a singly exponential number of operations, only.
Finally, our decomposition yields an answer to a question in a recent paper of
Almeida and Kl\'ima about varieties that are closed under Rees products.


title: Guido Castelnuovo e l'insegnamento della matematica

abstract:
  At the beginning of the 900s Guido Castelnuovo turned his attention toward
methodological, didactical, historical and applicative issues. He was an active
member of the ICMI (International Commission on Mathematical Instruction) and
of the Mathesis, an Italian association of mathematics teachers. He also was
the author of the mathematics curricula for the new Modern Lycee and he taught
the first University courses devoted to preservice training of mathematics
teachers. His course on Precision and Application Mathematics, inspired by
Felix Klein, shows Castelnuovo's point of view on mathematics and presents a
higher point of view on the programmes of the Modern Lycee.


title: K-stability for K\"ahler Manifolds

abstract:
  We formulate a notion of K-stability for K\"ahler manifolds, and prove one
direction of the Yau-Tian-Donaldson conjecture in this setting. More precisely,
we prove that the Mabuchi functional being bounded below (resp. coercive)
implies K-semistability (resp. uniformly K-stable). In particular this shows
that the existence of a constant scalar curvature K\"ahler metric implies
K-semistability, and K-stability if one assumes the automorphism group is
discrete. We also show how Stoppa's argument holds in the K\"ahler case, giving
a simpler proof of this K-stability statement.


title: Restrictions on Seshadri constants on surfaces

abstract:
  Starting with the pioneering work of Ein and Lazarsfeld restrictions on
values of Seshadri constants on algebraic surfaces have been studied by many
authors. In the present note we show how approximation involving continued
fractions combined with recent results of Kuronya and Lozovanu on Okounkov
bodies of line bundles on surfaces lead to effective statements considerably
restricting possible values of Seshadri constants. These results in turn
provide strong aditional evidence to a conjecture governing the Seshadri
constants on algebraic surfaces with Picard number 1.


title:
Common feature of concave growth pattern of oscillations in terms of
  speed, acceleration, fuel consumption and emission in car following:
  experiment and modeling

abstract:
  This paper has investigated the growth pattern of traffic oscillations by
using vehicle trajectory data in a car following experiment. We measured the
standard deviation of acceleration, emission and fuel consumption of each
vehicle in the car-following platoon. We found that: (1) Similar to the
standard deviation of speed, these indices exhibit a common feature of concave
growth pattern along vehicles in the platoon; (2) The emission and fuel
consumption of each vehicle decrease remarkably when the average speed of the
platoon increases from low value; However, when reaches 30km/h, the change of
emission and fuel consumption with is not so significant; (3), the correlations
of emission and fuel consumption with both the standard deviation of
acceleration and the speed oscillation are strong. Simulations show that with
the memory effect of drivers taken into account, the improved two-dimensional
intelligent driver model is able to reproduce the common feature of traffic
oscillation evolution quite well.


title: Even Trolls Are Useful: Efficient Link Classification in Signed Networks

abstract:
  We address the problem of classifying the links of signed social networks
given their full structural topology. Motivated by a binary user behaviour
assumption, which is supported by decades of research in psychology, we develop
an efficient and surprisingly simple approach to solve this classification
problem. Our methods operate both within the active and batch settings. We
demonstrate that the algorithms we developed are extremely fast in both
theoretical and practical terms. Within the active setting, we provide a new
complexity measure and a rigorous analysis of our methods that hold for
arbitrary signed networks. We validate our theoretical claims carrying out a
set of experiments on three well known real-world datasets, showing that our
methods outperform the competitors while being much faster.


title: Proof of Control of a UAV and a UGV Cooperating to Manipulate an Object

abstract:
  This paper focuses on the control of a system composed of an Unmanned Aerial
Vehicle (UAV) and an Unmanned Ground Vehicle (UGV) which cooperate to
manipulate an object. The two units are subject to actuator saturations and
cooperate to move the object to a desired pose, characterized by its position
and inclination. The paper proposes a control strategy where the ground vehicle
is tasked to deploy the object to a certain position, whereas the aerial
vehicle adjusts its inclination. The ground vehicle is governed by a saturated
proportional-derivative control law. The aerial vehicle is regulated by means
of a cascade control specifically designed for this problem that is able to
exploit the mechanical interconnection. The stability of the overall system is
proved through Input-to-State Stability and Small Gain theorem arguments. To
solve the problem of constraints satisfaction, a nonlinear Reference Governor
scheme is implemented. Numerical simulations are provided to demonstrate the
effectiveness of the proposed method.


title: A Solid-State Dielectric Elastomer Switch for Soft Logic

abstract:
  In this paper we describe a stretchable solid-state electronic switching
material that operates at high voltage potentials, as well as a switch material
benchmarking technique that utilizes a modular dielectric elastomer (artificial
muscle) ring oscillator. The solid-state switching material was integrated into
our oscillator, which self-started after 16s and performed 5 oscillations at a
frequency of 1.05Hz with 3.25kV DC input. Our materials-by-design approach for
the nickel filled polydimethysiloxane (Ni-PDMS) based switch has resulted in
significant improvements over previous carbon-grease based switches in four key
areas, namely sharpness of switching behavior upon applied stretch, magnitude
of electrical resistance change, ease of manufacture, and rate of production.
Switch lifetime was demonstrated to be in the range of tens to hundreds of
cycles with the current process. An interesting and potentially useful
strain-based switching hysteresis behavior is also presented.


title: Irreducible connections admit generic oper structures

abstract:
  Let G be a connected reductive group and X be a smooth curve over an
algebraically closed field of characteristic zero. We show that every
meromorphic G-connection on X admits a possibly degenerate oper structure; in
particular, every irreducible meromorphic G-connection admits a generic oper
structure.


title:
A DMFT+CTQMC Investigation of Strange Metallicity in Local Quantum
  Critical Scenario

abstract:
  Strange metallicity is now a pseudonym for a novel metallic state exhibiting
anomalous infra-red (branch-cut) continuum features in one and two particle
responses. Here, we employ dynamical mean-field theory (DMFT) using very
low-temperature continuous-time-quantum Monte-Carlo (CTQMC) solver for an
extended periodic Anderson model (EPAM) model to investigate unusual magnetic
fluctuations in the strange metal. We show how extinction of Landau
quasiparticles in the orbital selective Mott phase (OSMP) leads to (i)
qualitative explication of strange transport features and (ii) anomalous
quantum critical magnetic fluctuations due to critical liquid-like features in
dynamical spin fluctuations, in excellent accord with data in some f-electron
systems.


title: Extending DUNE: The dune-xt modules

abstract:
  We present our effort to extend and complement the core modules of the
Distributed and Unified Numerics Environment DUNE (http://dune-project.org) by
a well tested and structured collection of utilities and concepts. We describe
key elements of our four modules dune-xt-common, dune-xt-grid, dune-xt-la and
dune-xt-functions, which aim at further enabling the programming of generic
algorithms within DUNE as well as adding an extra layer of usability and
convenience.


title:
Dynamics of atomic and molecular solitary waves inatom-molecular hybrid
  Bose-Einstein condensates coupled by Magnetic Feshbach Resonance: Role of
  induced decays of Feshbach Molecules

abstract:
  Dynamics of atomic and molecular bright solitons in a hybrid atom-molecular
BEC (Bose Einstein Condensate) system of 85Rb coupled through Magnetic Feshbach
Resonance (MFR) has been investigated. By solving the time independent
atom-molecular coupled equations, the initial atomic and molecular
wavefunctions were obtained and the dynamics of the initial atomic and
molecular waves in a spherical one-dimensional trap were studied by solving the
time-dependent atom-molecular coupled equations. During evolution two types of
induced or stimulated decays of the feshbach molecules were switched on. These
two types of stimulated decays of the feshbach molecules to the two-atom
continuum and to the bound level of the lowest hyperfinee state of the molecule
were induced by laser or Radio Frequency fields. Hence the strength of these
two induced decays can be controlled by varying the laser or RF field
parameters e.g. intensity, detuning etc. It is found that depending on the
relative strength of these two types of stimulated or induced decays initial
atomic and molecular waves assume solitonic nature as bright solitons during
evolution and the stability of these solitonic waves can be achieved by
controlling the relative strength of induced decays in two different channels.
It is shown that these two induced decays lead to the formation of stable
atomic and molecular solitons by suppressing the initial oscillations and
instability in the atom-molecular coupled system of 85Rb atoms.


title:
Manifestly diffeomorphism invariant classical Exact Renormalization
  Group

abstract:
  We construct a manifestly diffeomorphism invariant Wilsonian (Exact)
Renormalization Group for classical gravity, and begin the construction for
quantum gravity. We demonstrate that the effective action can be computed
without gauge fixing the diffeomorphism invariance, and also without
introducing a background space-time. We compute classical contributions both
within a background-independent framework and by perturbing around a fixed
background, and verify that the results are equivalent. We derive the exact
Ward identities for actions and kernels and verify consistency. We formulate
two forms of the flow equation corresponding to the two choices of classical
fixed-point: the Gaussian fixed point, and the scale invariant interacting
fixed point using curvature-squared terms. We suggest how this programme may
completed to a fully quantum construction.


title:
Quark Matter in a Parallel Electric and Magnetic Field Background:
  Chiral Phase Transition and Equilibration of Chiral Density

abstract:
  In this article we study spontaneous chiral symmetry breaking for quark
matter in the background of static and homogeneous parallel electric field $\bm
E$ and magnetic field $\bm B$. We use a Nambu-Jona-Lasinio model with a local
kernel interaction to compute the relevant quantities to describe chiral
symmetry breaking at finite temperature for a wide range of $E$ and $B$. We
study the effect of this background on inverse catalysis of chiral symmetry
breaking for $E$ and $B$ of the same order of magnitude. We then focus on the
effect of equilibration of chiral density, $n_5$, produced dynamically by axial
anomaly on the critical temperature. The equilibration of $n_5$, a consequence
of chirality flipping processes in the thermal bath, allows for the
introduction of the chiral chemical potential, $\mu_5$, which is computed
self-consistently as a function of temperature and field strength by coupling
the number equation to the gap equation, and solving the two within an
expansion in $E/T^2$, $B/T^2$ and $\mu_5^2/T^2$. We find that even if chirality
is produced and equilibrates within a relaxation time $\tau_M$, it does not
change drastically the thermodynamics, with particular reference to the inverse
catalysis induced by the external fields, as long as the average $\mu_5$ at
equilibrium is not too large.


title:
Characterization of Optimal Feedback for Stochastic Linear Quadratic
  Control Problems

abstract:
  One of the fundamental issues in Control Theory is to design feedback
controls. It is well-known that, the purpose of introducing Riccati equations
in the deterministic case is to provide the desired feedback controls for
linear quadratic control problems. To date, the same problem in the stochastic
setting is only partially well-understood. In this paper, we establish the
equivalence between the existence of optimal feedback controls for the
stochastic linear quadratic control problems with random coefficients and the
solvability of the corresponding backward stochastic Riccati equations in a
suitable sense. We also give a counterexample showing the nonexistence of
feedback controls to a solvable stochastic linear quadratic control problem.
This is a new phenomenon in the stochastic setting, significantly different
from its deterministic counterpart.


title:
The kernel of the generalized Clifford-Fourier transform and its
  generating function

abstract:
  In this paper, we study the generalized Clifford-Fourier transform introduced
in [6] using the Laplace transform technique. We give explicit expressions in
the even dimensional case, we obtain polynomial bounds for the kernel functions
and establish a generating function.


title: Scaling limit and ageing for branching random walk in Pareto environment

abstract:
  We consider a branching random walk on the lattice, where the branching rates
are given by an i.i.d. Pareto random potential. We show that the system of
particles, rescaled in an appropriate way, converges in distribution to a
scaling limit that is interesting in its own right. We describe the limit
object as a growing collection of "lilypads" built on a Poisson point process
in $\mathbb{R}^d$. As an application of our main theorem, we show that the
maximizer of the system displays the ageing property.


title: The Survival Complex

abstract:
  We introduce a new way to associate a simplicial complex called the
\emph{survival complex} to a commutative semigroup with zero. Restricting our
attention to the semigroup of monomials arising from an Artinian monomial ring,
we determine that any such complex has an isolated point. Indeed, we show that
there is exactly one isolated point essentially only in the case where the
monomial ideal is generated purely by powers of the variables. This allows us
to recover Beintema's result that an Artinian monomial ring is Gorenstein if
and only if it is a complete intersection. A key ingredient of the translation
between the pure power result and Beintema's result is given by the one-to-one
correspondence we show between the so-called \emph{truly isolated} points of
our complex and the generators of the socle of the defining ideal. In another
relation between the geometry of the complex and the algebra of the ring, we
essentially give a correspondence between the nontrivial connected components
of the complex and the factors of a fibre product representation of the ring.
Finally, we explore algorithms for building survival complexes from specified
isolated points. That is, we work to build the ring out of a description of the
socle.


title: Simsun permutations, simsun successions and simsun patterns

abstract:
  In this paper, we introduce the definitions of simsun succession, simsun
cycle succession and simsun pattern. In particular, the ordinary simsun
permutations are permutations avoiding simsun pattern 321. We study the descent
and peak statistics on permutations avoiding simsun successions. We give a
combinatorial interpretation of the q-Eulerian polynomials introduced by Brenti
(J. Combin. Theory Ser. A 91 (2000), 137-170). We also present a bijection
between permutations avoiding simsun pattern 132 and set partitions.


title:
A Day of Your Days: Estimating Individual Daily Journeys Using Mobile
  Data to Understand Urban Flow

abstract:
  Nowadays, travel surveys provide rich information about urban mobility and
commuting patterns. But, at the same time, they have drawbacks: they are static
pictures of a dynamic phenomena, are expensive to make, and take prolonged
periods of time to finish. However, the availability of mobile usage data (Call
Detail Records) makes the study of urban mobility possible at levels not known
before. This has been done in the past with good results--mobile data makes
possible to find and understand aggregated mobility patterns. In this paper, we
propose to analyze mobile data at individual level by estimating daily
journeys, and use those journeys to build Origin-Destiny matrices to understand
urban flow. We evaluate this approach with large anonymized CDRs from Santiago,
Chile, and find that our method has a high correlation ($\rho = 0.89$) with the
current travel survey, and that it captures external anomalies in daily travel
patterns, making our method suitable for inclusion into urban computing
applications.


title: Strong Coordination over Multi-hop Line Networks

abstract:
  We analyze the problem of strong coordination over a multi-hop line network
in which the node initiating the coordination is a terminal network node. We
assume that each node has access to a certain amount of randomness that is
local to the node, and that the nodes share some common randomness, which are
used together with explicit hop-by-hop communication to achieve strong
coordination. We derive the trade-offs among the required rates of
communication on the network links, the rates of local randomness available to
network nodes, and the rate of common randomness to realize strong
coordination. We present an achievable coding scheme built using multiple
layers of channel resolvability codes, and establish several settings in which
this scheme is proven to offer the best possible trade-offs.


title: Quantum Errors and Disturbances: Response to Busch, Lahti and Werner

abstract:
  Busch, Lahti and Werner (BLW) have recently criticized the operator approach
to the description of quantum errors and disturbances. Their criticisms are
justified to the extent that the physical meaning of the operator definitions
has not hitherto been adequately explained. We rectify that omission. We then
examine BLW's criticisms in the light of our analysis. We argue that, although
the approach BLW favour (based on the Wasserstein 2-deviation) has its uses,
there are important physical situations where an operator approach is
preferable. We also discuss the reason why the error-disturbance relation is
still giving rise to controversies almost a century after Heisenberg first
stated his microscope argument. We argue that the source of the difficulties is
the problem of interpretation, which is not so wholly disconnected from
experimental practicalities as is sometimes supposed.


title: Pressure dependence of the magnetic ground states in MnP

abstract:
  MnP, a superconductor under pressure, exhibits a ferromagnetic order below
TC~290 K followed by a helical order with the spins lying in the ab plane and
the helical rotation propagating along the c axis below Ts~50 K at ambient
pressure. We performed single crystal neutron diffraction experiments to
determine the magnetic ground states under pressure. Both TC and Ts are
gradually suppressed with increasing pressure and the helical order disappears
at ~1.2 GPa. At intermediate pressures of 1.8 and 2.0 GPa, the ferromagnetic
order first develops and changes to a conical or two-phase (ferromagnetic and
helical) structure with the propagation along the b axis below a characteristic
temperature. At 3.8 GPa, a helical magnetic order appears below 208 K, which
hosts the spins in the ac plane and the propagation along the b axis. The
period of this b axis modulation is shorter than that at 1.8 GPa. Our results
indicate that the magnetic phase in the vicinity of the superconducting phase
may have a helical magnetic correlation along the b axis.


title: On commutative nonarchimedean Banach fields

abstract:
  We study the problem of whether a commutative nonarchimedean Banach ring
which is algebraically a field can be topologized by a multiplicative norm.
This can fail in general, but it holds for uniform Banach rings under some mild
extra conditions. Notably, any perfectoid ring whose underlying ring is a field
is a perfectoid field.


title: The VMC Survey. XIX. Classical Cepheids in the Small Magellanic Cloud

abstract:
  The VISTA near infrared Y, J, Ks survey of the Magellanic System (VMC) is
collecting deep Ks band time series photometry of pulsating variable stars
hosted by the two Magellanic Clouds and their connecting Bridge. In this paper,
we present Y, J, Ks light curves for a sample of 4172 Small Magellanic Cloud
(SMC) Classical Cepheids (CCs). These data, complemented with literature V
values, allowed us to construct a variety of period-luminosity (PL),
period-luminosity-color (PLC), and period-wesenheit (PW) relationships, valid
for Fundamental (F), First Overtone (FO) and Second Overtone (SO) pulsators.
The relations involving V, J, Ks bands are in agreement with their counterparts
in the literature. As for the Y band, to our knowledge we present the first CC
PL, PW, and PLC relations ever derived using this filter. We also present the
first near infrared PL, PW, and PLC relations for SO pulsators to date. We used
PW(V,Ks) to estimate the relative SMC-LMC distance and, in turn, the absolute
distance to the SMC. For the former quantity we find a value of
Delta(mu)=0.55+-0.04 mag, in rather good agreement with other evaluations based
on CCs, but significantly larger than the results obtained from older
population II distance indicators. This discrepancy might be due to the
different geometric distributions of young and old tracers in both Clouds. As
for the absolute distance to the SMC, our best estimates are
mu(SMC)=19.01+-0.05 mag and mu(SMC)=19.04+-0.06 mag, based on two distance
measurements to the LMC, which rely on accurate CC and eclipsing Cepheid binary
data, respectively.


title: Forward EW Physics at the LHC

abstract:
  Measurements of electroweak production in the forward region at the LHC
provide unique and complementary information to those performed in the central
region. Studies have been performed not just by LHCb, a dedicated forward
detector, but also by ATLAS and CMS, which are primarily situated in the
central region but can exploit forward calorimetry coverage to contribute to
the understanding of SM processes in the forward region.


title: Quantum difference equation for Nakajima varieties

abstract:
  For an arbitrary Nakajima quiver variety $X$, we construct an analog of the
quantum dynamical Weyl group acting in its equivariant K-theory. The correct
generalization of the Weyl group here is the fundamental groupoid of a certain
periodic locally finite hyperplane arrangement in $Pic(X)\otimes {\mathbb{C}}$.
We identify the lattice part of this groupoid with the operators of quantum
difference equation for $X$. The cases of quivers of finite and affine type are
illustrated by explicit examples.


title: Observation of Top Quark Production in the Forward Region at LHCb

abstract:
  Forward top production is observed, in the ${\mu}+b$ final state, with the 3
fb$^{-1}$ Run I dataset collected by the LHCb detector. The combined
cross-section for $t\bar{t}$ and single top production at $\sqrt{s}=7$ TeV and
$\sqrt{s}=8$ TeV is measured, for muons from the W boson with $p_{\rm T} > 25$
GeV in the pseudo-rapidity range 2.0$< \eta <$4.5 and with a b-tagged jet with
50$ < p_{\rm T} < 100$ GeV in the pseudorapidity range 2.2$< \eta <$4.2. The
production cross-sections are found to be in agreement with NLO predictions.


title: Equivalence relations invariant under group actions

abstract:
  We extend some recent results about bounded invariant equivalence relations
and invariant subgroups of definable groups: we show that type-definability and
smoothness are equivalent conditions in a wider class of relations than
heretofore considered, which includes all the cases for which the equivalence
was proved before. As a by-product, we show some analogous results in purely
topological context (without direct use of model theory).


title:
A 14 $h^{-3}$ Gpc$^3$ study of cosmic homogeneity using BOSS DR12 quasar
  sample

abstract:
  The BOSS quasar sample is used to study cosmic homogeneity with a 3D survey
in the redshift range $2.2<z<2.8$. We measure the count-in-sphere, $N(<\! r)$,
i.e. the average number of objects around a given object, and its logarithmic
derivative, the fractal correlation dimension, $D_2(r)$. For a homogeneous
distribution $N(<\! r) \propto r^3$ and $D_2(r)=3$. Due to the uncertainty on
tracer density evolution, 3D surveys can only probe homogeneity up to a
redshift dependence, i.e. they probe so-called "spatial isotropy". Our data
demonstrate spatial isotropy of the quasar distribution in the redshift range
$2.2<z<2.8$ in a model-independent way, independent of any FLRW fiducial
cosmology, resulting in $3-\langle D_2 \rangle < 1.7 \times 10^{-3}$ (2
$\sigma$) over the range $250<r<1200 \, h^{-1}$Mpc for the quasar distribution.
If we assume that quasars do not have a bias much less than unity, this implies
spatial isotropy of the matter distribution on large scales. Then, combining
with the Copernican principle, we finally get homogeneity of the matter
distribution on large scales. Alternatively, using a flat $\Lambda$CDM fiducial
cosmology with CMB-derived parameters, and measuring the quasar bias relative
to this $\Lambda$CDM model, our data provide a consistency check of the model,
in terms of how homogeneous the Universe is on different scales. $D_2(r)$ is
found to be compatible with our $\Lambda$CDM model on the whole $10<r<1200 \,
h^{-1}$Mpc range. For the matter distribution we obtain $3-\langle D_2 \rangle
< 5 \times 10^{-5}$ (2 $\sigma$) over the range $250<r<1200 \, h^{-1}$Mpc,
consistent with homogeneity on large scales.


title:
Universal Dynamic Magnetism in Yb-Pyrochlores with Disparate Ground
  States

abstract:
  The ytterbium pyrochlore magnets, Yb2B2O7 (B = Sn, Ti, Ge) are well described
by S_eff = 1/2 quantum spins decorating a network of corner-sharing tetrahedra
and interacting via anisotropic exchange. Structurally, only the non-magnetic
B-site cation, and hence, primarily the lattice parameter, is changing across
the series. Nonetheless, a range of magnetic behaviors are observed: the low
temperature magnetism in Yb2Ti2O7 and Yb2Sn2O7 has ferromagnetic character,
while Yb2Ge2O7 displays an antiferromagnetically ordered Neel state at low
temperatures. While the static properties of the ytterbium pyrochlores are
distinct, inelastic neutron scattering measurements reveal a common character
to their exotic spin dynamics. All three ytterbium pyrochlores show a gapless
continuum of spin excitations, resembling over-damped ferromagnetic spin waves
at low Q. Furthermore, the specific heat of the series also follows a common
form, with a broad, high-temperature anomaly followed by a sharp
low-temperature anomaly at T_C or T_N. The novel spin dynamics we report
correlate strongly with the broad specific heat anomaly only, remaining
unchanged across the sharp anomaly. This result suggests that the primary order
parameter in the ytterbium pyrochlores associated with the sharp anomaly is
"hidden" and not simple magnetic dipole order.


title: Spark deficient Gabor frames

abstract:
  The theory of Gabor frames of functions defined on finite abelian groups was
initially developed in order to better understand the properties of Gabor
frames of functions defined over the reals. However, during the last twenty
years the topic has acquired an interest of its own. One of the fundamental
questions asked in this finite setting is the existence of full spark Gabor
frames. The author proved the existence, as well as constructed such frames,
when the underlying group is finite cyclic. In this paper, we resolve the
non-cyclic case; in particular, we show that there can be no full spark Gabor
frames of windows defined on finite abelian non-cyclic groups. We also prove
that all eigenvectors of certain unitary matrices in the Clifford group in odd
dimensions generate spark deficient Gabor frames. Finally, similarities between
the uncertainty principles concerning the finite dimensional Fourier transform
and the short-time Fourier transform are discussed.


title: Beyond CCA: Moment Matching for Multi-View Models

abstract:
  We introduce three novel semi-parametric extensions of probabilistic
canonical correlation analysis with identifiability guarantees. We consider
moment matching techniques for estimation in these models. For that, by drawing
explicit links between the new models and a discrete version of independent
component analysis (DICA), we first extend the DICA cumulant tensors to the new
discrete version of CCA. By further using a close connection with independent
component analysis, we introduce generalized covariance matrices, which can
replace the cumulant tensors in the moment matching framework, and, therefore,
improve sample complexity and simplify derivations and algorithms
significantly. As the tensor power method or orthogonal joint diagonalization
are not applicable in the new setting, we use non-orthogonal joint
diagonalization techniques for matching the cumulants. We demonstrate
performance of the proposed models and estimation techniques on experiments
with both synthetic and real datasets.


title: GRB 141221A: gone is the wind

abstract:
  GRB 141221A was observed from infrared to soft gamma-ray bands. Here, we
investigate its properties, in light of the standard model. We find that the
optical light curve of the afterglow of this burst presents an unusual
steep/quick rise. The broad band spectral energy distribution taken near the
maximum of the optical emission presents either a thermal component or a
spectral break. In the former case, the properties of the afterglow are then
very unusual, but could explain the lack of apparent jet breaks in the Swift
light curves. In the latter case, the afterglow properties of this burst are
more usual, and we can see in the light curves the passing through of the
injection and cooling frequencies within the optical bands, not masked by a
reverse shock. This model also excludes the presence of a stellar wind,
challenging either the stellar progenitor properties, or the very stellar
nature of the progenitor itself. In all cases, this burst may be a part of a
Rosetta stone that could help to explain some of the most striking features
discovered by Swift during the last ten years.


title:
Measurement of the forward-backward asymmetry of top-quark and antiquark
  pairs using the full CDF Run II data set

abstract:
  We measure the forward--backward asymmetry of the production of top quark and
antiquark pairs in proton-antiproton collisions at center-of-mass energy
$\sqrt{s} = 1.96~\mathrm{TeV}$ using the full data set collected by the
Collider Detector at Fermilab (CDF) in Tevatron Run II corresponding to an
integrated luminosity of $9.1~\rm{fb}^{-1}$. The asymmetry is characterized by
the rapidity difference between top quarks and antiquarks ($\Delta y$), and
measured in the final state with two charged leptons (electrons and muons). The
inclusive asymmetry, corrected to the entire phase space at parton level, is
measured to be $A_{\text{FB}}^{t\bar{t}} = 0.12 \pm 0.13$, consistent with the
expectations from the standard-model (SM) and previous CDF results in the final
state with a single charged lepton. The combination of the CDF measurements of
the inclusive $A_{\text{FB}}^{t\bar{t}}$ in both final states yields
$A_{\text{FB}}^{t\bar{t}}=0.160\pm0.045$, which is consistent with the SM
predictions. We also measure the differential asymmetry as a function of
$\Delta y$. A linear fit to $A_{\text{FB}}^{t\bar{t}}(|\Delta y|)$, assuming
zero asymmetry at $\Delta y=0$, yields a slope of $\alpha=0.14\pm0.15$,
consistent with the SM prediction and the previous CDF determination in the
final state with a single charged lepton. The combined slope of
$A_{\text{FB}}^{t\bar{t}}(|\Delta y|)$ in the two final states is
$\alpha=0.227\pm0.057$, which is $2.0\sigma$ larger than the SM prediction.


title: Some ring-theoretic properties of A_inf

abstract:
  The ring of Witt vectors over a perfect valuation ring of characteristic p,
often denoted A_inf, plays a pivotal role in p-adic Hodge theory; for instance,
Bhatt, Morrow, and Scholze have recently reinterpreted and refined the
crystalline comparison isomorphism by relating it to a certain A_inf-valued
cohomology theory. We address some basic ring-theoretic questions about A_inf
motivated by analogies with two-dimensional regular local rings. For example,
we show that in most cases A_inf, which is manifestly not noetherian, is also
not coherent. On the other hand, it does have the property that vector bundles
over the complement of the closed point in Spec A_inf do extend uniquely over
the puncture; moreover, a similar statement holds in Huber's category of adic
spaces.


title: Sampling of General Correlators in Worm Algorithm-based Simulations

abstract:
  Using the complex $\phi^4$-model as a prototype for a system which is
simulated by a worm algorithm, we show that not only the charged correlator
$<\phi^{*}(x)\phi(y)>$, but also more general correlators such as
$<|\phi(x)||\phi(y)|>$ or $<\text{arg}(\phi(x))\text{arg}(\phi(y))>$, as well
as condensates like $<|\phi|>$, can be measured at every step of the Monte
Carlo evolution of the worm instead of on closed-worm configurations only. The
method generalizes straightforwardly to other systems simulated by worms, such
as spin or sigma models.


title: New insights from cosmic gamma rays

abstract:
  The measurement of gamma rays from cosmic sources at MeV energies is one of
the key tools for nuclear astrophysics, in its study of nuclear reactions and
their impacts on objects and phenomena throughout the universe. Gamma rays
trace nuclear processes most directly, as they originate from nuclear
transitions following radioactive decays or high-energy collisions with
excitation of nuclei. Additionally, the unique gamma-ray signature from the
annihilation of positrons falls into this astronomical window and is discussed
here: Cosmic positrons are often produced from beta-decays, thus also of
nuclear physics origins. The nuclear reactions leading to radioactive isotopes
occur inside stars and stellar explosions, which therefore constitute the main
objects of such studies. In recent years, both thermonuclear and core-collapse
supernova radioactivities have been measured, and complement conventional
supernova observations with measurements of their prime energy sources. The
diffuse radioactive afterglow of massive-star nucleosynthesis in gamma rays is
now being analysed towards how massive stars feed back their energy and ejecta
into interstellar gas. Large interstellar cavities and superbubbles have been
recognised to be the dominating structures where new massive-star ejecta are
injected, from 26Al gamma-ray spectroscopy. Finally, the puzzling
bulge-dominated intensity distribution of positron annihilation gamma rays is
measured in greater detail, but still not understood; a recent microquasar
flare provided evidence that such objects may be prime sources for positrons in
interstellar space, rather than distributed nucleosynthesis. We also briefly
discuss the status and prospects for astronomy with telescopes for the
nuclear-radiation energy window.


title:
State-of-the-art in Power Line Communications: from the Applications to
  the Medium

abstract:
  In recent decades, power line communication has attracted considerable
attention from the research community and industry, as well as from regulatory
and standardization bodies. In this article we provide an overview of both
narrowband and broadband systems, covering potential applications, regulatory
and standardization efforts and recent research advancements in channel
characterization, physical layer performance, medium access and higher layer
specifications and evaluations. We also identify areas of current and further
study that will enable the continued success of power line communication
technology.


title:
On the light quark mass effects in Higgs boson production in gluon
  fusion

abstract:
  Production of Higgs bosons at the LHC is affected by the contribution of
light quarks, that mediate the gg \to Hg transition. Although their impact is
suppressed by small Yukawa couplings, it is enhanced by large logarithms of the
ratio of the Higgs boson mass or its transverse momentum to light quark masses.
We study the origin of this enhancement, focusing on the abelian corrections to
gg \to Hg amplitudes of the form (C_F alphas L^{2})^n, where $L \in {
ln(s/mb^2), ln(p_\perp^2/mb^2) }. We show how these non-Sudakov double
logarithmic terms can be resummed to all orders in the strong coupling
constant. Interestingly, we find that the transverse momentum dependence of
these corrections is very weak due to a peculiar cancellation between different
logarithmic terms. Although the abelian part of QCD corrections is not expected
to be dominant, it can be used to estimate missing higher-order corrections to
light quark contributions to Higgs boson production at the LHC.


title: Asymptotic dynamics of three-dimensional gravity

abstract:
  These are the lectures notes of the course given at the Eleventh Modave
Summer School in Mathematical Physics, 2015, aimed at PhD candidates and junior
researchers in theoretical physics. We review in details the result of
Coussaert-Henneaux-van Driel showing that the asymptotic dynamics of $(2+1)$-
dimensional gravity with negative cosmological constant is described at the
classical level by Liouville theory. Boundary conditions implement the
asymptotic reduction in two steps: the first set reduces the $SL(2,\mathbb
R)\times SL(2,\mathbb R)$ Chern-Simons action, equivalent to the Einstein
action, to a non-chiral $SL(2,\mathbb R)$ Wess-Zumino-Witten model, while the
second set imposes constraints on the WZW currents that reduce further the
action to Liouville theory. We discuss the issues of considering the latter as
an effective description of the dual conformal field theory describing AdS$_3$
gravity beyond the semi-classical regime.


title: The parameterized space complexity of embedding along a path

abstract:
  The embedding problem is to decide, given an ordered pair of structures,
whether or not there is an injective homomorphism from the first structure to
the second. We study this problem using an established perspective in
parameterized complexity theory: the universe size of the first structure is
taken to be the parameter, and we define the embedding problem relative to a
class ${\cl A}$ of structures to be the restricted version of the general
problem where the first structure must come from ${\cl A}$. We initiate a
systematic complexity study of this problem family, by considering classes
whose structures are what we call rooted path structures; these structures have
paths as Gaifman graphs. Our main theorem is a dichotomy theorem on classes of
rooted path structures.


title:
Testing Elementary Cycles Formulation of Quantum Mechanics in Carbon
  Nanotubes and Superconductivity

abstract:
  Elementary Cycles are intrinsic periodic phenomena, classical in the essence,
whose classical relativistic dynamics reproduce the complete coherence (perfect
recurrences) typically associated to the pure quantum behaviours of elementary
particles. They can be regarded as effective representations of 't Hooft
Cellular Automata. By means of Elementary Cycles physics we obtain a
consistent, intuitive, novel derivation of the peculiar quantum dynamics of
electrons in Carbon Nanotubes, as well as of Superconductivity fundamental
phenomenology. In particular we derive, from classical arguments, the essential
electronic properties of graphene systems, such as energy bands and density of
states. Similarly, in the second part of the paper, we derive the
Superconductivity fundamental phenomenology in terms of simple geometrical
considerations, directly from the Elementary Cycles dynamics rather than from
empirical aspects and effective quantities connected to the microscopical
characteristics of materials as in the standard approaches to
Superconductivity. With this approach simple geometrical considerations about
the competition between the quantum recurrence and the thermal noise allow for
a novel interpretation of the occurrence of high temperature superconductivity
and the related gauge symmetry breaking mechanism.


title:
Measurements of the t-tbar production cross section in lepton+jets final
  states in pp collisions at 8 TeV and ratio of 8 to 7 TeV cross sections

abstract:
  A measurement of the top quark pair production (t-tbar) cross section in
proton-proton collisions at the centre-of-mass energy of 8 TeV is presented
using data collected with the CMS detector at the LHC, corresponding to an
integrated luminosity of 19.6 inverse femtobarns. This analysis is performed in
the t-tbar decay channels with one isolated, high transverse momentum electron
or muon and at least four jets, at least one of which is required to be
identified as originating from hadronization of a b quark. The calibration of
the jet energy scale and the efficiency of b jet identification are determined
from data. The measured t-tbar cross section is 228.5 +/- 3.8 (stat) +/- 13.7
(syst) +/- 6.0 (lumi) pb. This measurement is compared with an analysis of 7
TeV data, corresponding to an integrated luminosity of 5.0 inverse femtobarns,
to determine the ratio of 8 TeV to 7 TeV cross sections, which is found to be
1.43 +/- 0.04 (stat) +/- 0.07 (syst) +/- 0.05 (lumi). The measurements are in
agreement with QCD predictions up to next-to-next-to-leading order.


title: Criteria of Divergence Almost Everywhere in Ergodic Theory

abstract:
  In this expository paper, we survey nowadays classical tools or criteria used
in problems of convergence everywhere to build counterexamples: the Stein
continuity principle, Bourgain's entropy criteria and Kakutani-Rochlin lemma,
most classical device for these questions in ergodic theory. First, we state a
$L^1$-version of the continuity principle and give an example of its usefulness
by applying it to some famous problem on divergence almost everywhere of
Fourier series. Next we particularly focus on entropy criteria in $L^p$, $2\le
p\le \infty$ and provide detailed proofs. We also study the link between the
associated maximal operators and the canonical Gaussian process on $L^2$. We
further study the corresponding criterion in $L^p$, $1<p<2$ using properties of
$p$-stable processes. Finally we consider Kakutani-Rochlin's lemma, one of the
most frequently used tool in ergodic theory, by stating and proving a criterion
for a.e. divergence of weighted ergodic averages.


title:
Broadband THz spectroscopy of the insulator-metal transition driven by
  coherent lattice deformation at the SmNiO3/LaAlO3 interface

abstract:
  We investigate the non-equilibrium insulator-metal transition driven in a
SmNiO3 thin film by coherent optical excitation of the LaAlO3 substrate
lattice. By probing the transient optical properties over a broad frequency
range (100 - 800 cm^-1), we analyze both the time dependent metallic plasma and
the infrared optical phonon line shapes. We show that the light-induced
metallic phase in SmNiO3 has the same carrier density as the equilibrium
metallic phase. We also report that the LaAlO3 substrate acts as a transducer
only at the earlier time delays, as the vibrations are driven coherently. No
long-lived structural rearrangement takes place in the substrate. Finally, we
show that the transient insulator-metal transition occurs both below and above
the N\'eel temperature. We conclude that the supersonic melting of magnetic
order measured with ultrafast x-rays is not the driving force of the formation
of the metallic phase. We posit that the insulator metal transition may origin
from the rearrangement of ordered charges at the interface propagating into the
film.


title:
Elliptic Hypergeometric Summations by Taylor Series Expansion and
  Interpolation

abstract:
  We use elliptic Taylor series expansions and interpolation to deduce a number
of summations for elliptic hypergeometric series. We extend to the well-poised
elliptic case results that in the $q$-case have previously been obtained by
Cooper and by Ismail and Stanton. We also provide identities involving S.
Bhargava's cubic theta functions.


title:
Sum-Rate Maximization for Linearly Precoded Downlink Multiuser MISO
  Systems with Partial CSIT: A Rate-Splitting Approach

abstract:
  This paper considers the Sum-Rate (SR) maximization problem in downlink
MU-MISO systems under imperfect Channel State Information at the Transmitter
(CSIT). Contrary to existing works, we consider a rather unorthodox
transmission scheme. In particular, the message intended to one of the users is
split into two parts: a common part which can be recovered by all users, and a
private part recovered by the corresponding user. On the other hand, the rest
of users receive their information through private messages. This
Rate-Splitting (RS) approach was shown to boost the achievable Degrees of
Freedom (DoF) when CSIT errors decay with increased SNR. In this work, the RS
strategy is married with linear precoder design and optimization techniques to
achieve a maximized Ergodic SR (ESR) performance over the entire range of SNRs.
Precoders are designed based on partial CSIT knowledge by solving a stochastic
rate optimization problem using means of Sample Average Approximation (SAA)
coupled with the Weighted Minimum Mean Square Error (WMMSE) approach. Numerical
results show that in addition to the ESR gains, the benefits of RS also include
relaxed CSIT quality requirements and enhanced achievable rate regions compared
to conventional transmission with NoRS.


title:
Influence of surface conductivity on the apparent zeta potential of
  calcite

abstract:
  Zeta potential is a physicochemical parameter of particular importance in
describing the surface electrical properties of charged porous media. However,
the zeta potential of calcite is still poorly known because of the difficulty
to interpret streaming potential experiments. The Helmholtz-Smoluchowski (HS)
equation is widely used to estimate the apparent zeta potential from these
experiments. However, this equation neglects the influence of surface
conductivity on streaming potential. We present streaming potential and
electrical conductivity measurements on a calcite powder in contact with an
aqueous NaCl electrolyte. Our streaming potential model corrects the apparent
zeta potential of calcite by accounting for the influence of surface
conductivity and flow regime. We show that the HS equation seriously
underestimates the zeta potential of calcite, particularly when the electrolyte
is diluted (ionic strength < 0.01 M) because of calcite surface conductivity.
The basic Stern model successfully predicted the corrected zeta potential by
assuming that the zeta potential is located at the outer Helmholtz plane, i.e.
without considering a stagnant diffuse layer at the calcite-water interface.
The surface conductivity of calcite crystals was inferred from electrical
conductivity measurements and computed using our basic Stern model. Surface
conductivity was also successfully predicted by our surface complexation model.


title: Ultra-Low-Temperature Reactions of Carbon Atoms with Hydrogen Molecules

abstract:
  The reactions of carbon atoms with dihydrogen have been investigated in
liquid helium droplets at $T$ = 0.37 K. A calorimetric technique was applied to
monitor the energy released in the reaction. The barrierless reaction between a
single carbon atom and a single dihydrogen molecule was detected. Reactions
between dihydrogen clusters and carbon atoms have been studied by
high-resolution mass spectrometry. The formation of hydrocarbon cations of the
type C$_m$H$_n^+$, with $m$ = 1-4 and $n$ = 1-15 was observed. With enhanced
concentration of dihydrogen, the mass spectra demonstrated the main "magic"
peak assigned to the CH$_5^+$ cation. A simple formation pathway and the high
stability of this cation suggest its high abundance in the interstellar medium.


title:
Ab initio determination of effective electron-phonon coupling factor in
  copper

abstract:
  The electron temperature dependent electron density of states, Fermi-Dirac
distribution, and electron-phonon spectral function are computed as
prerequisites before achieving effective electron-phonon coupling factor. The
obtained coupling factor is implemented into a molecular dynamics (MD) and
two-temperature model (TTM) coupled simulation of femtosecond laser heating. By
monitoring temperature evolutions of electron and lattice subsystems, the
result utilizing coupling factor from ab initio calculation, shows a faster
decrease of electron temperature and increase of lattice temperature than those
using coupling factor from phenomenological treatment. The approach of
calculating coupling factor and its implementation into MD-TTM simulation is
applicable to other metals.


title: A remark on Deligne's finiteness theorem

abstract:
  Over a connected geometrically unibranch scheme $X$ of finite type over a
finite field, we show finiteness of the number of irreducible $\bar
\Q_\ell$-lisse sheaves, with bounded rank and bounded ramification in the sense
of Drinfeld, up to twist by a character of the finite field. On $X$ smooth,
with bounded ramification in the sense of bounding the Swan conductors on
curves, this is Deligne's theorem. Version 2: We prove also that for Deligne's
finiteness theorem, it is enough to assume $X$ normal. However, the proof uses
the smooth case, unlike the proof in the case of bounded ramification in the
sense of Drinfeld. Finally we discuss the various notions of boundedness of
ramification used.


title: The pitch angle paradox and radiative life times in a synchrotron source

abstract:
  In synchrotron radiation there is a paradox whether or not the pitch angle of
a radiating charge varies. The conventional wisdom is that the pitch angle does
not change during the radiation process. The argument is based on Larmor's
radiation formula, where in a synchrotron case the radiation power is along the
instantaneous direction of motion of the charge. Then the momentum loss will
also be parallel to that direction and therefore the pitch angle of the charge
would remain unaffected. The accordingly derived formulas for energy losses of
synchrotron electrons in radio galaxies are the standard text-book material for
the last 50 years. However, if we use the momentum transformation laws from
special relativity, then we find that the pitch angle of a radiating charge
varies. While the velocity component parallel to the magnetic field remains
unaffected, the perpendicular component does reduce in magnitude due to
radiative losses, implying a change in the pitch angle. This apparent paradox
is resolved when effects on the charge motion are calculated not from Larmor's
formula but from Lorentz's radiation reaction formula. We derive the exact
formulation by taking into account the change of the pitch angle due to
radiative losses. From this we first time derive the characteristic decay time
of synchrotron electrons over which they turn from highly relativistic into
mildly relativistic ones.


title:
SUePDF: a program to obtain quantitative pair distribution function from
  electron diffraction data

abstract:
  SUePDF is a graphic-user-interface program written in MATLAB to achieve
quantitative pair distribution functions (PDF) from electron diffraction data.
The program facilitates the structural studies of amorphous materials and small
nanoparticles based on electron diffraction data from transmission electron
microscopes (TEMs). It is based on the physics of electron scattering as well
as the total scattering methodology. A method of background modelling is
introduced to treat the intensity tail of the direct beam, inelastic scattering
and incoherent multiple scattering. Kinematical electron scattering intensity
is scaled using the electron scattering factors. The PDFs obtained after
Fourier transforms are normalized with respect to number density, nanoparticle
form factor, and the non-negativity of probability density. SUePDF is
distributed as free software for academic users.

categories: cond-mat.mtrl-sci cond-mat.mes-hall cond-mat.other physics.comp-ph physics.ins-det


title: Free loop space and the cyclic bar construction

abstract:
  Using the $E_\infty-$structure on singular cochains, we construct a homotopy
coherent map from the cyclic bar construction of the differential graded
algebra of cochains on a space to a model for the cochains on its free loop
space. This fills a gap in the paper "Cyclic homology and equivariant homology"
by John D.S. Jones.


title: On the Kontsevich $\star$-product associativity mechanism

abstract:
  The deformation quantization by Kontsevich [arXiv:q-alg/9709040] is a way to
construct an associative noncommutative star-product $\star=\times+\hbar \{\ ,\
\}_{P}+\bar{o}(\hbar)$ in the algebra of formal power series in $\hbar$ on a
given finite-dimensional affine Poisson manifold: here $\times$ is the usual
multiplication, $\{\ ,\ \}_{P}\neq0$ is the Poisson bracket, and $\hbar$ is the
deformation parameter. The product $\star$ is assembled at all powers
$\hbar^{k\geq0}$ via summation over a certain set of weighted graphs with $k+2$
vertices; for each $k>0$, every such graph connects the two co-multiples of
$\star$ using $k$ copies of $\{\ ,\ \}_{P}$. Cattaneo and Felder [
arXiv:math/9902090 [math.QA] ] interpreted these topological portraits as the
genuine Feynman diagrams in the Ikeda-Izawa model [arXiv:hep-th/9312059] for
quantum gravity.
  By expanding the star-product up to $\bar{o}(\hbar^3)$, i.e., with respect to
graphs with at most five vertices but possibly containing loops, we illustrate
the mechanism Assoc = Operator(Poisson) that converts the Jacobi identity for
the bracket $\{\ ,\ \}_{P}$ into the associativity of $\star$.
  Key words: Deformation quantization, associative algebra, Poisson bracket,
graph complex, star-product
  PACS: 02.40.Sf, 02.10.Ox, 02.40.Gh, also 04.60.-m


title: Algorithms on Ideal over Complex Multiplication order

abstract:
  We show in this paper that the Gentry-Szydlo algorithm for cyclotomic orders,
previously revisited by Lenstra-Silverberg, can be extended to
complex-multiplication (CM) orders, and even to a more general structure. This
algorithm allows to test equality over the polarized ideal class group, and
finds a generator of the polarized ideal in polynomial time. Also, the
algorithm allows to solve the norm equation over CM orders and the recent
reduction of principal ideals to the real suborder can also be performed in
polynomial time. Furthermore, we can also compute in polynomial time a unit of
an order of any number field given a (not very precise) approximation of it.
Our description of the Gentry-Szydlo algorithm is different from the original
and Lenstra- Silverberg's variant and we hope the simplifications made will
allow a deeper understanding. Finally, we show that the well-known speed-up for
enumeration and sieve algorithms for ideal lattices over power of two
cyclotomics can be generalized to any number field with many roots of unity.