title:
Introduction of impermeable actin-staining molecules to mammalian cells
  by optoporation

abstract:
  The selective insertion of foreign materials, such as fluorescent markers or
plasmids, into living cells has been a challenging problem in cell
biology.However, it is often necessary that researchers insert such materials
into cells for various dynamical and/or drug delivery studies. This problem
becomes even more challenging if the study is to be limited to specific cells
within a larger population, since other transfection methods, such as viral
transfection and lipofection, are not realizable with a high degree of spatial
selectivity.Here, we have used a focused femtosecond laser beam to create a
small transient hole in the cellular membrane (optoporation) in order to inject
nanomolar concentrations of rhodamine phalloidin (an impermeable dye molecule
for staining filamentous actin) into targeted living mammalian cells (both HEK
and primary cortical neurons).Following optoporation, the bound to the
intracellular actin network and rise in fluorescence intensity was observed...


title:
Causal Discovery from Subsampled Time Series Data by Constraint
  Optimization

abstract:
  This paper focuses on causal structure estimation from time series data in
which measurements are obtained at a coarser timescale than the causal
timescale of the underlying system. Previous work has shown that such
subsampling can lead to significant errors about the system's causal structure
if not properly taken into account. In this paper, we first consider the search
for the system timescale causal structures that correspond to a given
measurement timescale structure. We provide a constraint satisfaction procedure
whose computational performance is several orders of magnitude better than
previous approaches. We then consider finite-sample data as input, and propose
the first constraint optimization approach for recovering the system timescale
causal structure. This algorithm optimally recovers from possible conflicts due
to statistical errors. More generally, these advances allow for a robust and
non-parametric estimation of system timescale causal structures from subsampled
time series data.


title: Order-disorder transition in repulsive self-propelled particle systems

abstract:
  We study the collective dynamics of repulsive self-propelled particles. The
particles are governed by coupled equations of motion that include polar
self-propulsion, damping of velocity and of polarity, repulsive
particle-particle interaction, and deterministic dynamics. Particle dynamics
simulations show that the collective coherent motion with large density
fluctuations spontaneously emerges from a disordered, isotropic state. In the
parameter region where the rotational damping of polarity is strong, the
systems undergoes an abrupt shift to the absorbing ordered state after a
waiting period in the metastable disordered state. In order to obtain a simple
understanding of the mechanism underlying the collective behavior, we analyze
binary particle scattering process. We show that this approach correctly
predicts the order-disorder transition at dilute limit. The same approach is
expanded for finite densities, although it disagrees with the result from
many-particle simulations due to many-body correlations and density
fluctuations.


title: White-Light Flares on Close Binaries Observed with Kepler

abstract:
  Based on Kepler data, we present the results of a search for white-light
flares on 1049 close binaries. We identify 234 flare binaries, on which 6818
flares are detected. We compare the flare-binary fraction in different binary
morphologies ("detachedness"). The result shows that the fractions in
over-contact and ellipsoidal binaries are approximately 10-20 percent lower
than those in detached and semi-detached systems. We calculate the binary
flares activity level (AL) of all the flare binaries, and discuss its
variations along the orbital period (P_orb) and rotation period (P_rot,
calculated for only detached binaries). We find that AL increases with
decreasing P_orb or P_rot up to the critical values at P_orb near 3 days or
P_rot near 1.5 days, thereafter, the AL starts decreasing no matter how fast
the stars rotate. We examine the flaring rate as a function of orbital phase in
2 eclipsing binaries on which a large number of flares are detected. It appears
that there is no correlation between flaring rate and orbital phase in these 2
binaries. In contrast, when we examine the function with 203 flares on 20
non-eclipse ellipsoidal binaries, bimodal distribution of amplitude weighted
flare numbers shows up at orbital phase 0.25 and 0.75. Such variation could be
larger than what is expected from the cross-section modification.


title: Smooth loop stacks of differentiable stacks and gerbes

abstract:
  R\'esum\'e. Nous d\'efinissons un groupo\"ide de Fr\'echet-Lie Map(S^1,X)
d'ana-foncteurs du cercle vers un groupo\"ide de Lie X. Ceci fournit une
pr\'esentation du Hom-champ Hom(S^1,\cX), o\`u \cX est le champ
diff\'erentiable associ\'e \`a X. Nous appliquons cette construction au
groupo\"ide de Lie sous-jacent au `gerbe fibr\'e' d'une vari\'et\'e
diff\'erentiable M; le r\'esultat est un gerbe fibr\'e au-dessus de l'espace
des lacets LM de M.
  Abstract. We define a Fr\'echet--Lie groupoid Map(S^1,X) of anafunctors from
the circle into a Lie groupoid X. This provides a presentation of the Hom-stack
Hom(S^1,\cX), where \cX is the differentiable stack associated to X. We apply
this construction to the Lie groupoid underlying a bundle gerbe on a manifold
M; the result is a bundle gerbe on the loop space LM of M.


title:
Evaluation of selected recurrence measures in discriminating pre-ictal
  and inter-ictal periods from epileptic EEG data

abstract:
  We investigate the suitability of selected measures of complexity based on
recurrence quantification analysis and recurrence networks for an
identification of pre-seizure states in multi-day, multi-channel, invasive
electroencephalographic recordings from five epilepsy patients. We employ
several statistical techniques to avoid spurious findings due to various
influencing factors and due to multiple comparisons and observe precursory
structures in three patients. Our findings indicate a high congruence among
measures in identifying seizure precursors and emphasize the current notion of
seizure generation in large-scale epileptic networks. A final judgment of the
suitability for field studies, however, requires evaluation on a larger
database.


title: Magnetic Mass in 4D AdS Gravity

abstract:
  We provide a fully-covariant expression for the diffeomorphic charge in 4D
anti-de Sitter gravity, when the Gauss-Bonnet and Pontryagin terms are added to
the action. The couplings of these topological invariants are such that the
Weyl tensor and its dual appear in the on-shell variation of the action, and
such that the action is stationary for asymptotic (anti) self-dual solutions in
the Weyl tensor. In analogy with Euclidean electromagnetism, whenever the
self-duality condition is global, both the action and the total charge are
identically vanishing. Therefore, for such configurations the magnetic mass
equals the Ashtekhar-Magnon-Das definition.


title: Characterization of a dense aperture array for radio astronomy

abstract:
  EMBRACE@Nancay is a prototype instrument consisting of an array of 4608
densely packed antenna elements creating a fully sampled, unblocked aperture.
This technology is proposed for the Square Kilometre Array and has the
potential of providing an extremely large field of view making it the ideal
survey instrument. We describe the system,calibration procedures, and results
from the prototype.


title: Meteor observations with Mini-MegaTORTORA wide-field monitoring system

abstract:
  Here we report on the results of meteor observations with 9-channel
Mini-MegaTORTORA (MMT-9) wide-field optical monitoring system with high
temporal resolution. During first 1.5 years of operation more than 90 thousands
of meteors have been detected, at a rate of 300-350 per night, with durations
from 0.1 to 2.5 seconds and angular velocities up to 38 degrees per second. The
faintest detected meteors has the peak brightness about 10 mag, while the
majority - from 4 to 8 mag. Some of the meteors have been observed in BVR
filters simultaneously. Color variations along the trail for them are
determined. All parameters of detected meteors are published online. The
database also includes the information on 10 thousands meteors detected by our
previous FAVOR camera in 2006-2009 years.


title:
Contrasting Effects of Replication in Parallel Systems: From Overload to
  Underload and Back

abstract:
  Task replication has recently been advocated as a practical solution to
reduce latencies in parallel systems. In addition to several convincing
empirical studies, some others provide analytical results, yet under some
strong assumptions such as Poisson arrivals, exponential service times, or
independent service times of the replicas themselves, which may lend themselves
to some contrasting and perhaps contriving behavior. For instance, under the
second assumption, an overloaded system can be stabilized by a replication
factor, but can be sent back in overload through further replication. In turn,
under the third assumption, strictly larger stability regions of replication
systems do not necessarily imply smaller delays.
  Motivated by the need to dispense with such common and restricting
assumptions, which may additionally cause unexpected behavior, we develop a
unified and general theoretical framework to compute tight bounds on the
distribution of response times in general replication systems. These results
immediately lend themselves to the optimal number of replicas minimizing
response time quantiles, depending on the parameters of the system (e.g., the
degree of correlation amongst replicas). As a concrete application of our
framework, we design a novel replication policy which can improve the stability
region of classical fork-join queueing systems by $\mathcal{O}(\ln K)$, in the
number of servers $K$.


title: Octonionic geometry and conformal transformations

abstract:
  We describe space-time using split octonions over the reals and use their
group of automorphisms, the non-compact form of Cartan's exceptional Lie group
G2, as the main geometrical group of the model. Connections of the G2-rotations
of octonionic 8D space with the conformal transformations in 4D Minkowski
space-time are studied. It is shown that the dimensional constant needed in
these analysis naturally gives the observed value of the cosmological constant.


title: Mechanism for quantum speedup in open quantum systems

abstract:
  The quantum speed limit (QSL) time for open system characterizes the most
efficient response of the system to the environmental influences. Previous
results showed that the non-Markovianity governs the quantum speedup. Via
studying the dynamics of a dissipative two-level system, we reveal that the
non-Markovian effect is only the dynamical way of the quantum speedup, while
the formation of the system-environment bound states is the essential reason
for the quantum speedup. Our attribution of the quantum speedup to the
energy-spectrum character can supply another vital path for experiments when
the quantum speedup shows up without any dynamical calculations. The potential
experimental observation of our quantum speedup mechanism in the circuit QED
system is discussed. Our results may be of both theoretical and experimental
interests in exploring the ultimate QSL in realistic environments, and may open
new perspectives for devising active quantum speedup devices.


title: Non-Markovian Dynamics in Ultracold Rydberg Aggregates

abstract:
  We propose a setup of an open quantum system in which the environment can be
tuned such that either Markovian or non-Markovian system dynamics can be
achieved. The implementation uses ultracold Rydberg atoms, relying on their
strong long-range interactions. Our suggestion extends the features available
for quantum simulators of molecular systems employing Rydberg aggregates and
presents a new test bench for fundamental studies of the classification of
system-environment interactions and the resulting system dynamics in open
quantum systems.


title: TASI Lectures on the Conformal Bootstrap

abstract:
  These notes are from courses given at TASI and the Advanced Strings School in
summer 2015. Starting from principles of quantum field theory and the
assumption of a traceless stress tensor, we develop the basics of conformal
field theory, including conformal Ward identities, radial quantization,
reflection positivity, the operator product expansion, and conformal blocks. We
end with an introduction to numerical bootstrap methods, focusing on the 2d and
3d Ising models.


title:
Nature of charge density waves and superconductivity in
  1\emph{T}-TaSe$_{2-x}$Te$_x$

abstract:
  Transition-metal dichalcogenides (TMDs) $MX_2$ ($M$ = Ti, Nb, Ta; $X$ = S,
Se, Te) exhibit a rich set of charge density wave (CDW) orders, which usually
coexist and/or compete with superconductivity. The mechanisms of CDWs and
superconductivity in TMDs are still under debate. Here we perform an
investigation on a typical TMD system, 1\emph{T}-TaSe$_{2-x}$Te$_x$ ($0 \leq x
\leq 2$). Doping-induced disordered distribution of Se/Te suppresses CDWs in
1\emph{T}-TaSe$_2$. A domelike superconducting phase with the maximum
$T_\textrm{c}^{\textrm{onset}}$ of 2.5 K was observed near CDWs. The
superconducting volume is very small inside the CDW phase and becomes very
large instantly when the CDW phase is fully suppressed. The observations can be
understood based on the strong \emph{\textbf{q}}-dependent electron-phonon
coupling-induced periodic-lattice-distortion (PLD) mechanism of CDWs. The
volume variation of superconductivity implies the emergence of domain walls in
the suppressing process of CDWs. Our concluded scenario makes a fundamental
understanding about CDWs and related superconductivity in TMDs.


title:
Uniaxial pressure induced half-metallic ferromagnetic phase transition
  in LaMnO$_3$

abstract:
  We use first-principles theory to predict that the application of uniaxial
compressive strain leads to a transition from an antiferromagnetic insulator to
a ferromagnetic half-metal phase in LaMnO$_3$. We identify the Q2 Jahn-Teller
mode as the primary mechanism that drives the transition, indicating that this
mode can be used to tune the lattice, charge, and spin coupling. Applying
$\simeq$ 6 GPa of uniaxial pressure along the [010] direction activates the
transition to a half-metallic $\textit{pseudo-cubic}$ state. The
half-metallicity opens the possibility of producing colossal magnetoresistance
in the stoichiometric LaMnO$_3$ compound at significantly lower pressure
compared to recently observed investigations using hydrostatic pressure.


title: How effective can simple ordinal peer grading be?

abstract:
  Ordinal peer grading has been proposed as a simple and scalable solution for
computing reliable information about student performance in massive open online
courses. The idea is to outsource the grading task to the students themselves
as follows. After the end of an exam, each student is asked to rank -- in terms
of quality -- a bundle of exam papers by fellow students. An aggregation rule
then combines the individual rankings into a global one that contains all
students. We define a broad class of simple aggregation rules, which we call
type-ordering aggregation rules, and present a theoretical framework for
assessing their effectiveness. When statistical information about the grading
behaviour of students is available (in terms of a noise matrix that
characterizes the grading behaviour of the average student from a student
population), the framework can be used to compute the optimal rule from this
class with respect to a series of performance objectives that compare the
ranking returned by the aggregation rule to the underlying ground truth
ranking. For example, a natural rule known as Borda is proved to be optimal
when students grade correctly. In addition, we present extensive simulations
that validate our theory and prove it to be extremely accurate in predicting
the performance of aggregation rules even when only rough information about
grading behaviour (i.e., an approximation of the noise matrix) is available.
Both in the application of our theoretical framework and in our simulations, we
exploit data about grading behaviour of students that have been extracted from
two field experiments in the University of Patras.


title:
ARPES view of orbitally resolved quasiparticle lifetimes in iron
  pnictides

abstract:
  We study with ARPES the renormalization and quasiparticle lifetimes of the
$d_{xy}$ and $d_{xz}$/$d_{yz}$ orbitals in two iron pnictides, LiFeAs and
Ba(Fe$_{0.92}$Co$_{0.08}$)$_2$As$_2$ (Co8). We find that both quantities depend
on orbital character rather than on the position on the Fermi Surface (for
example hole or electron pocket). In LiFeAs, the renormalizations are larger
for $d_{xy}$, while they are similar on both types of orbitals in Co8. The most
salient feature, which proved robust against all the ARPES caveats we could
think of, is that the lifetimes for $d_{xy}$ exhibit a markedly different
behavior than those for $d_{xz}$/$d_{yz}$. They have smaller values near $E_F$
and exhibit larger $\omega$ and temperature dependences. While the behavior of
$d_{xy}$ is compatible with a Fermi liquid description, it is not the case for
$d_{xz}$/$d_{yz}$. This situation should have important consequences for the
physics of iron pnictides, which have not been considered up to now. More
generally, it raises interesting questions on how a Fermi liquid regime can be
established in a multiband system with small effective bandwidths.


title: A $p$-adic Hermitian Maass lift

abstract:
  For $K$ an imaginary quadratic field with discriminant $-D_K$ and associated
quadratic Galois character $\chi_K$, Kojima, Gritsenko and Krieg studied a
Hermitian Maass lift of elliptic modular cusp forms of level $D_K$ and
nebentypus $\chi_K$ via Hermitian Jacobi forms to Hermitian modular forms of
level one for the unitary group $U(2,2)$ split over $K$. We generalize this
(under certain conditions on $K$ and $p$) to the case of $p$-oldforms of level
$pD_K$ and character $\chi_K$. To do this, we define an appropriate Hermitian
Maass space for general level and prove that it is isomorphic to the space of
special Hermitian Jacobi forms. We then show how to adapt this construction to
lift a Hida family of modular forms to a $p$-adic analytic family of
automorphic forms in the Maass space of level $p$.


title: Thermal Conductivity of Segmented Nanowires

abstract:
  We present a review of the phonon thermal conductivity of segmented nanowires
focusing on theoretical results for Si and Si/Ge structures with the constant
and periodically modulated cross-sections. We describe the use of the
face-centered cubic cell and Born-von Karman models of the lattice vibrations
for calculating the phonon energy spectra in the segmented nanowires.
Modification of the phonon spectrum in such nanostructures results in strong
reduction of the phonon thermal conductivity and suppression of heat transfer
due to a trapping of phonon modes in nanowire segments. Possible practical
applications of segmented nanowires in thermoelectric energy generation are
also discussed.


title:
Oscillating solutions of the Vlasov-Poisson system -- A numerical
  investigation

abstract:
  Numerical evidence is given that spherically symmetric perturbations of
stable spherically symmetric steady states of the gravitational Vlasov-Poisson
system lead to solutions which oscillate in time. The oscillations can be
periodic in time or damped. Along one-parameter families of polytropic steady
states we establish an Eddington-Ritter type relation which relates the period
of the oscillation to the central density of the steady state. The numerically
obtained periods are used to estimate possible periods for typical elliptical
galaxies.


title:
Incommensurate Counterrotating Magnetic Order Stabilized by Kitaev
  Interactions in the Layered Honeycomb ${\alpha}$-Li$_2$IrO$_3$

abstract:
  The layered honeycomb magnet $\alpha$-Li$_2$IrO$_3$ has been theoretically
proposed as a candidate to display novel magnetic behaviour associated with
Kitaev interactions between spin-orbit entangled $j_{\rm eff}=1/2$ magnetic
moments on a honeycomb lattice. Here we report single crystal magnetic resonant
x-ray diffraction combined with powder magnetic neutron diffraction to reveal
an incommensurate magnetic order in the honeycomb layers with Ir magnetic
moments counter-rotating on nearest-neighbour sites. This type of magnetic
structure has not been reported experimentally before in honeycomb magnets and
cannot be explained by a spin Hamiltonian with dominant isotropic (Heisenberg)
couplings. The magnetic structure shares many key features with the magnetic
order in the structural polytypes $\beta$ and $\gamma$-Li$_2$IrO$_3$,
understood theoretically to be stabilized by dominant Kitaev interactions
between Ir moments located on the vertices of three-dimensional hyperhoneycomb
and stripyhoneycomb lattices, respectively. Based on this analogy and a
theoretical soft-spin analysis of magnetic ground states for candidate spin
Hamiltonians, we propose that Kitaev interactions also dominate in
$\alpha$-Li$_2$IrO$_3$, indicative of universal Kitaev physics across all three
members of the harmonic honeycomb family of Li$_2$IrO$_3$ polytypes.


title: Mode matching in second order susceptibility metamaterials

abstract:
  We present an effective model for a subwavelength periodically patterned
metallic layer, its cavities being filled with a nonlinear dielectric material,
which accounts for both the linear and second order behavior. The effective non
linear susceptibility for the homogenized layer is driven by the nonlinearity
of the dielectric material and by the geometrical parameters, thus leading to
much higher susceptibility than existing materials. This leads to a huge
enhancement of non linear processes when used together with resonances.
Furthermore, multiple resonances are taking place in the metallic cavities, and
we investigate the mode matching situations for frequency conversion processes
and show how it enhances further their efficiency.


title: Waves and null congruences in a draining bathtub

abstract:
  We study wave propagation in a draining bathtub: a fluid-mechanical black
hole analogue in which perturbations are governed by a Klein-Gordon equation on
an effective Lorentzian geometry. Like the Kerr spacetime, the draining bathtub
geometry possesses an (effective) horizon, an ergosphere and null circular
orbits. We propose that a `pulse' disturbance may be used to map out the
light-cone of the effective geometry. First, we apply the eikonal approximation
to elucidate the link between wavefronts, null geodesic congruences and the
Raychaudhuri equation. Next, we solve the wave equation numerically in the time
domain using the method of lines. Starting with Gaussian initial data, we
demonstrate that a pulse will propagate along a null congruence and thus trace
out the light-cone of the effective geometry. Our numerical results reveal
features, such as wavefront intersections, frame-dragging, winding and
interference effects, that are closely associated with the presence of null
circular orbits and the ergosphere.


title: Turning on gravity with the Higgs mechanism

abstract:
  We investigate how a Higgs mechanism could be responsible for the emergence
of gravity in extensions of Einstein theory. In this scenario, at high
energies, symmetry restoration could "turn off" gravity, with dramatic
implications for cosmology and quantum gravity. The sense in which gravity is
muted depends on the details of the implementation. In the most extreme case
gravity's dynamical degrees of freedom would only be unleashed after the Higgs
field acquires a non-trivial vacuum expectation value, with gravity reduced to
a topological field theory in the symmetric phase. We might also identify the
Higgs and the Brans-Dicke fields in such a way that in the unbroken phase
Newton's constant vanishes, decoupling matter and gravity. We discuss the broad
implications of these scenarios.


title: Operator Lipschitz Functions

abstract:
  The purpose of this survey article is a comprehensive study of operator
Lipschitz functions. A continuous function $f$ on the real line ${\Bbb R}$ is
called operator Lipschitz if $\|f(A)-f(B)\|\le{\rm const}\|A-B\|$ for arbitrary
self-adjoint operators $A$ and $B$. We give sufficient conditions and necessary
conditions for operator Lipschitzness. We also study the class of operator
differentiable functions on ${\Bbb R}$. Then we consider operator Lipschitz
functions on closed subsets of the plane as well as commutator Lipschitz
functions on such subsets. Am important role is played by double operator
integrals and Schur multipliers.


title: A multidimensional analogue of the Rademacher-Gaussian tail comparison

abstract:
  We prove a dimension-free tail comparison between the Euclidean norms of sums
of independent random vectors uniformly distributed in centred Euclidean
spheres and properly rescaled standard Gaussian random vectors.


title: Linear resolutions of powers and products

abstract:
  The goal of this paper is to present examples of families of homogeneous
ideals in the polynomial ring over a field that satisfy the following
condition: every product of ideals of the family has a linear free resolution.
As we will see, this condition is strongly correlated to good primary
decompositions of the products and good homological and arithmetical properties
of the associated multi-Rees algebras. The following families will be discussed
in detail: polymatroidal ideals, ideals generated by linear forms and Borel
fixed ideals of maximal minors. The main tools are Gr\"obner bases and Sagbi
deformation.


title:
GPU performance analysis of a nodal discontinuous Galerkin method for
  acoustic and elastic models

abstract:
  Finite element schemes based on discontinuous Galerkin methods possess
features amenable to massively parallel computing accelerated with general
purpose graphics processing units (GPUs). However, the computational
performance of such schemes strongly depends on their implementation. In the
past, several implementation strategies have been proposed. They are based
exclusively on specialized compute kernels tuned for each operation, or they
can leverage BLAS libraries that provide optimized routines for basic linear
algebra operations. In this paper, we present and analyze up-to-date
performance results for different implementations, tested in a unified
framework on a single NVIDIA GTX980 GPU. We show that specialized kernels
written with a one-node-per-thread strategy are competitive for polynomial
bases up to the fifth and seventh degrees for acoustic and elastic models,
respectively. For higher degrees, a strategy that makes use of the NVIDIA
cuBLAS library provides better results, able to reach a net arithmetic
throughput 35.7% of the theoretical peak value.


title:
Sunspot Observations and Counting at Specola Solare Ticinese in Locarno
  since 1957

abstract:
  Specola Solare Ticinese is an observatory dedicated to Sunspot Number
counting, which was constructed in 1957 in Locarno, Southern Switzerland, as an
external observing station of the Zurich Federal Observatory. When in 1981 the
responsibility of the determination of the International Sunspot Number was
assumed by the Royal Observatory of Belgium, Specola Solare Ticinese was given
the role of pilot station, with the aim of preserving the continuity in the
counting method. We report the observing procedure and counting rules applied
in Locarno.


title:
A general state-sum construction of 2-dimensional topological quantum
  field theories with defects

abstract:
  We derive the general state sum construction for 2D topological quantum field
theories (TQFTs) with source defects on oriented curves, extending the
state-sum construction from special symmetric Frobenius algebra for 2-D TQFTs
without defects (cf. Lauda \& Pfeiffer \cite{LP}). From the extended Pachner
moves (Crane \& Yetter \cite{CY}), we derive equations that we subsequently
translate into string diagrams so that we can easily observe their properties.
As in Dougherty, Park and Yetter \cite{DPY}, we require that triangulations be
flag-like, meaning that each simplex of the triangulation is either disjoint
from the defect curve, or intersects it in a closed face, and that the extended
Pachner moves preserve flag-likeness.
  This research was conducted under the mentorship of Prof. David Yetter at
Kansas State University with the support of NSF grant DMS-1262877.


title: On the geometry of Riemannian manifolds with density

abstract:
  We introduce a new geometric approach to a manifold equipped with a smooth
density function that takes a torsion-free affine connection, as opposed to a
weighted measure or Laplacian, as the fundamental object of study. The
connection motivates new versions of the volume and Laplacian comparison
theorems that are valid for the 1-Bakry-Emery Ricci tensor, a weaker assumption
than has previously been considered in the literature. As applications we prove
new generalizations of Myers' theorem and Cheng's diameter rigidity result. We
also investigate the holonomy groups of the weighted connection. We show that
they are more general than the Riemannian holonomy, but also exhibit some of
the same structure. For example, we obtain a generalization of the de Rham
splitting theorem as well as new rigidity phenomena for parallel vector fields.
A general feature of all of our rigidity results is that warped or twisted
product splittings are characterized, as opposed to the usual isometric
products.


title:
Guiding of positive streamers in nitrogen, argon and N$_{2}$-O$_{2}$
  mixtures by very low $n_{e}$ laser-induced pre-ionization trails

abstract:
  In previous work we have shown that positive streamers in pure nitrogen can
be guided by a laser-induced trail of low electron density. Here we show more
detailed results from such measurements. We show the sensitivity of this
laser-guiding on pressure p and found that the maximum delay between the laser
pulse and voltage pulse for guiding scales with something between $1/p$ and
$1/p^{2}$. We also show that when we use a narrower laser beam the laser
guiding occurs less frequent and that when we move the laser beam away from the
symmetry axis, guiding hardly is observed. Finally we show that laser guiding
can also occur in pure argon.


title: Essential dimension and the flats spanned by a point set

abstract:
  Let $P$ be a finite set of points in $\mathbb{R}^d$ or $\mathbb{C}^d$. We
answer a question of Purdy on the conditions under which the number of
hyperplanes spanned by $P$ is at least the number of $(d-2)$-flats spanned by
$P$.
  In answering this question, we define a new measure of the degeneracy of a
point set with respect to affine subspaces, termed the "essential dimension".
We use the essential dimension to give an asymptotic expression for the number
of $k$-flats spanned by $P$, for $1 \leq k \leq d-1$.


title:
Average transverse momenta of baryon production at p-p collider
  experiments and their crucial implications for the high energy
  hadroproduction physics

abstract:
  The phenomenological approach in the framework of Quark-Gluon String Model
(QGSM) has been applied to the description of transverse momentum spectra for
the baryon production at colliders. The analysis of data on hyperon transverse
momentum distributions,dN/dp_t, demonstrates a difference in the dynamics of
multiparticle production in proton-proton vs. antiproton-proton collisions in
the region of low p_t . The most important contribution in antip-p reaction
goes from fragmentation of antidiquark-diquark side of pomeron diagram. The
complete study of the energy dependence of average transverse momenta for the
energies from sqrt(s)= 0.2 to 7. TeV shows the slight growing of <p_t> with
energy. No dramatic changes were seen on the range from Tevatron to LHC, which
may be responsible for "knee" in the cosmic ray proton spectra. The average
transverse momentum analysis through the different mass of hadrons reveals some
regularity in the mass gaps between the hadron generations. This observation
suggests that more hadrons with the following masses 13.7, 37.3, 101.5, 276,
750 ... GeV are expected by geometrical progression with the mass factor of
order $\delta{lnM}$=1 . These states may possess new quantum numbers beyond the
Standard Model. The possibility of QGSM to construct the spectra of baryons in
the whole range of x_F gives obvious advantages in the description of
production asymmetries: the baryon-over-antibaryon access in the central region
of proton-proton collisions, the baryon-to-meson abnormal ratios in
nucleus-nucleus reactions, the growing ratios of secondary particles in cosmic
ray spectra as well as the recently observed negative asymmetry for charmed
baryon/antibaryon spectra at the far rapidity point Y=2 in LHCb experiment.
This study, based on the routine analysis of collider data, has many crucial
implications for the entire field of hadroproduction physics.


title: A topological view on algebraic computation models

abstract:
  We investigate the topological aspects of some algebraic computation models,
in particular the BSS-model. Our results can be seen as bounds on how different
BSS-computability and computability in the sense of computable analysis can be.
The framework for this is Weihrauch reducibility. As a consequence of our
characterizations, we establish that the solvability complexity index is
(mostly) independent of the computational model, and that there thus is common
ground in the study of non-computability between the BSS and TTE setting.


title:
Average Energy Expended Per e-h Pair and Energy Scale Function for
  Germanium-Based Dark Matter Experiments

abstract:
  We report a new result of the temperature-dependent average energy expended
per electron-hole (e-h) pair, $\varepsilon$, for germanium detectors. Applying
energy partition mechanism in ionization for a given energy deposition, the
Fano factor and the value of $\varepsilon$ can be determined separately.
Subsequently, we illustrate the variation of $\varepsilon$ as a function of
temperature. The impact of $\varepsilon$ on the energy threshold and energy
scale for germanium detectors at a given temperature is evaluated. We
demonstrate an absolute energy scale function of low-energy recoils for
germanium detectors in the direct detection of dark matter particles.


title: Adaptive estimation of High-Dimensional Signal-to-Noise Ratios

abstract:
  We consider the equivalent problems of estimating the residual variance, the
proportion of explained variance $\eta$ and the signal strength in a
high-dimensional linear regression model with Gaussian random design. Our aim
is to understand the impact of not knowing the sparsity of the regression
parameter and not knowing the distribution of the design on minimax estimation
rates of $\eta$. Depending on the sparsity $k$ of the regression parameter,
optimal estimators of $\eta$ either rely on estimating the regression parameter
or are based on U-type statistics, and have minimax rates depending on $k$. In
the important situation where $k$ is unknown, we build an adaptive procedure
whose convergence rate simultaneously achieves the minimax risk over all $k$ up
to a logarithmic loss which we prove to be non avoidable. Finally, the
knowledge of the design distribution is shown to play a critical role. When the
distribution of the design is unknown, consistent estimation of explained
variance is indeed possible in much narrower regimes than for known design
distribution.


title: Practical Riemannian Neural Networks

abstract:
  We provide the first experimental results on non-synthetic datasets for the
quasi-diagonal Riemannian gradient descents for neural networks introduced in
[Ollivier, 2015]. These include the MNIST, SVHN, and FACE datasets as well as a
previously unpublished electroencephalogram dataset. The quasi-diagonal
Riemannian algorithms consistently beat simple stochastic gradient gradient
descents by a varying margin. The computational overhead with respect to simple
backpropagation is around a factor $2$. Perhaps more interestingly, these
methods also reach their final performance quickly, thus requiring fewer
training epochs and a smaller total computation time.
  We also present an implementation guide to these Riemannian gradient descents
for neural networks, showing how the quasi-diagonal versions can be implemented
with minimal effort on top of existing routines which compute gradients.


title: High precision analysis of the solar twin HIP 100963

abstract:
  Methods. We used the HIRES spectrograph on the Keck I telescope to acquire
high-resolution (R $\approx$ 70000) spectra with a high signal-to-noise ratio
(S/N $\approx$ 400 - 650 per pixel) of HIP 100963 and the Sun for a
differential abundance analysis. We measured the equivalent widths (EWs) of
iron lines to determine the stellar parameters by employing the differential
spectroscopic equilibrium. We determined the composition of volatile,
refractory, and neutron-capture elements through a differential abundance
analysis with respect to the Sun.
  Results. The stellar parameters we found are $T_{\rm{eff}}=5818 \pm 4$ K, log
$g = 4.49 \pm 0.01$ dex, $v_{t} = 1.03 \pm 0.01 $ $\rm{km\ {s}}^{-1}$ , and
[Fe/H] $ = -\ 0.003 \pm 0.004$ dex. These low errors allow us to compute a
precise mass ($1.03^{+0.02}_{-0.01}$ M$_{\odot}$) and age (2.0 $\pm$ 0.4 Gyr),
obtained using Yonsei-Yale isochrones. Using our [Y/Mg] ratio, we have
determined an age of $2.1 \pm 0.4$ Gyr, in agreement with the age computed
using isochrones. Our isochronal age also agrees with the age determined from
stellar activity (2.4 $\pm$ 0.3 Gyr). We study the abundance pattern with
condensation temperature ($\rm{T_{cond}}$) taking corrections by the GCE into
account. We show that the enhancements of neutron-capture elements are
explained by contributions from both the $s$- and $r$-process. The lithium
abundance follows the tight Li-age correlation seen in other solar twins.
  Conclusions. We confirm that HIP 100963 is a solar twin and demonstrate that
its abundance pattern is about solar after corrections for GCE. The star also
shows enrichment in $s-$ and $r$-process elements, as well as depletion in
lithium that is caused by stellar evolution.


title:
Mesoscopic Superposition States Generated by Synthetic Spin-orbit
  Interaction in Fock-state Lattices

abstract:
  Mesoscopic superposition states of photons can be prepared in three cavities
interacting with the same two-level atom. By periodically modulating the three
cavity frequencies around the transition frequency of the atom with $2\pi/3$
phase difference, the time reversal symmetry is broken and an optical
circulator is generated with chiralities depending on the quantum state of the
atom. A superposition of the atomic states can guide photons from one cavity to
a mesoscopic superposition of the other two cavities. The physics can be
understood in a finite spin-orbit-coupled Fock-state lattice where the atom and
the cavities carry the spin and the orbit degrees of freedom, respectively.
This scheme can be realized in circuit QED architectures and provides a new
platform for exploring quantum information and topological physics in novel
lattices.


title:
Joint Scheduling and Power-Control for Delay Guarantees in Heterogeneous
  Cognitive Radios

abstract:
  An uplink multi secondary user (SU) cognitive radio system having average
delay constraints as well as an interference constraint to the primary user
(PU) is considered. If the interference channels between the SUs and the PU are
statistically heterogeneous due to the different physical locations of the
different SUs, the SUs will experience different delay performances. This is
because SUs located closer to the PU transmit with lower power levels. Two
dynamic scheduling-and-power-allocation policies that can provide the required
average delay guarantees to all SUs irrespective of their locations are
proposed. The first policy solves the problem when the interference constraint
is an instantaneous one, while the second is for problems with long-term
average interference constraints. We show that although the average
interference problem is an extension to the instantaneous interference one, the
solution is totally different. The two policies, derived using the Lyapunov
optimization technique, are shown to be asymptotically delay optimal while
satisfying the delay and interference constraints. Our findings are supported
by extensive system simulations and shown to outperform existing policies as
well as shown to be robust to channel estimation errors.


title:
What if the Masses of the First Two Quark Families are not Generated by
  the Standard Higgs?

abstract:
  We point out that, in the context of the SM, $|V^2_{13}| + | V^2_{23}|$ is
expected to be large, of order one. The fact that $|V^2_{13}| + |V^2_{23}|
\approx 1.6 \times 10^{-3}$ motivates the introduction of a symmetry S which
leads to $V_{CKM} ={1\>\!\!\!\mathrm{I}} $, with only the third generation of
quarks acquiring mass. We consider two scenarios for generating the mass of the
first two quark generations and full quark mixing. One consists of the
introduction of a second Higgs doublet which is neutral under S. The second
scenario consists of assuming New Physics at a high energy scale , contributing
to the masses of light quark generations, in an effective field theory
approach. This last scenario leads to couplings of the Higgs particle to
$s\overline s$ and $c \overline c$ which are significantly enhanced with
respect to those of the SM. In both schemes, one has scalar-mediated flavour-
changing neutral currents which are naturally suppressed. Flavour violating top
decays are predicted in the second scenario at the level $ \mbox{Br} (t
\rightarrow h c ) \geq 5\times 10^{-5}$.


title: Roughness in quotient groups

abstract:
  The theory of rough sets was firstly introduced by Pawlak (see \cite{p}).
Many Mathematician has been studied the relations between rough sets and
algebraic systems such as groups, rings and modules. In this paper we will
introduce the lower and upper approximations in a quotient group. We will
discuss several properties of the lower and upper approximations. Moreover
under some additional assumptions we are able to show that the lower
approximation is a normal subgroup of the quotient group but this property
fails for the upper approximation. At the end we will develop several
homomorphisms between lower approximations.


title: Gigantic directional asymmetry of luminescence in multiferroic CuB2O4

abstract:
  We report direction dependent luminescence (DDL), i.e., the asymmetry in the
luminescence intensity between the opposite directions of the emission, in
multiferroic CuB2O4. Although it is well known that the optical constants can
change with the reversal of the propagation direction of light in multiferroic
materials, the largest asymmetry in the luminescence intensity was 0.5 % so
far. We have performed a measurement of photoluminescence with a He-Ne laser
irradiation (633 nm). The luminescence intensity changes by about 70 % with the
reversal of the magnetic field due to the interference between the electric
dipole and magnetic dipole transitions. We also demonstrate the imaging of the
canted antiferromagnetic domain structure of (Cu,Ni)B2O4 by using the large
DDL.


title: Survival of pq-superstrings in field theory simulations

abstract:
  We perform large-scale field theoretical simulations in expanding universe to
characterize a network of strings that can form composed bound states. The
network consists of two copies of Abelian Higgs strings (which we label p and
q, respectively) coupled via a potential term to give pq bound states. The
simulations are performed using two different kinds of initial conditions: the
first one with a network of p- and q-strings, and the second one with a network
of q- and pq-strings. This way, we start from two opposite situations: one with
no initial pq-strings, and one with a large initial number of pq-strings. We
find that in both cases the system scales, and in both cases the system prefers
to have a low fraction of pq-strings. This is somewhat surprising in the case
for the second type of conditions, showing that the unzipping mechanism is very
efficient. We also find hints that both initial conditions tend to asymptote to
a common configuration, though we would need a larger dynamical range to
confirm it. The average velocities of the different types of strings in the
network have also been explored for the first time.


title: Modeling helicity dissipation-rate equation

abstract:
  Transport equation of the dissipation rate of turbulent helicity is derived
with the aid of a statistical analytical closure theory of inhomogeneous
turbulence. It is shown that an assumption on the helicity scaling with an
algebraic relationship between the helicity and its dissipation rate leads to
the transport equation of the turbulent helicity dissipation rate without
resorting to a heuristic modeling.


title:
Justification of the Nonlinear Schr\"odinger approximation for a
  quasilinear Klein-Gordon equation

abstract:
  We consider a nonlinear Klein-Gordon equation with a quasilinear quadratic
term. The Nonlinear Schr\"odinger (NLS) equation can be derived as a formal
approximation equation describing the evolution of the envelopes of slowly
modulated spatially and temporarily oscillating wave packet-like solutions to
the quasilinear Klein-Gordon equation. It is the purpose of this paper to
present a method which allows one to prove error estimates in Sobolev norms
between exact solutions of the quasilinear Klein-Gordon equation and the formal
approximation obtained via the NLS equation. The paper contains the first
validity proof of the NLS approximation of a nonlinear hyperbolic equation with
a quasilinear quadratic term by error estimates in Sobolev spaces. We expect
that the method developed in the present paper will allow an answer to the
relevant question of the validity of the NLS approximation for other
quasilinear hyperbolic systems.


title: Meta-learning within Projective Simulation

abstract:
  Learning models of artificial intelligence can nowadays perform very well on
a large variety of tasks. However, in practice different task environments are
best handled by different learning models, rather than a single, universal,
approach. Most non-trivial models thus require the adjustment of several to
many learning parameters, which is often done on a case-by-case basis by an
external party. Meta-learning refers to the ability of an agent to autonomously
and dynamically adjust its own learning parameters, or meta-parameters. In this
work we show how projective simulation, a recently developed model of
artificial intelligence, can naturally be extended to account for meta-learning
in reinforcement learning settings. The projective simulation approach is based
on a random walk process over a network of clips. The suggested meta-learning
scheme builds upon the same design and employs clip networks to monitor the
agent's performance and to adjust its meta-parameters "on the fly". We
distinguish between "reflexive adaptation" and "adaptation through learning",
and show the utility of both approaches. In addition, a trade-off between
flexibility and learning-time is addressed. The extended model is examined on
three different kinds of reinforcement learning tasks, in which the agent has
different optimal values of the meta-parameters, and is shown to perform well,
reaching near-optimal to optimal success rates in all of them, without ever
needing to manually adjust any meta-parameter.


title:
Real hypersurfaces in complex hyperbolic two-plane Grassmannians with
  commuting structure Jacobi operators

abstract:
  In this paper, we introduce a new commuting condition between the structure
Jacobi operator and symmetric (1,1)-type tensor field $T$, that is,
$R_{\xi}\phi T=TR_{\xi}\phi$, where $T=A$ or $T=S$ for Hopf hypersurfaces in
complex hyperbolic two-plane Grassmannians. By using simultaneous
diagonalzation for commuting symmetric operators, we give a complete
classification of real hypersurfaces in complex hyperbolic two-plane
Grassmannians with commuting condition respectively.


title: Arrows of time in unconfined systems

abstract:
  Entropy and the second law of thermodynamcs were discovered through study of
the behaviour of gases in confined spaces. The related techniques developed in
the kinetic theory of gases have failed to resolve the apparent conflict
between the time-reversal symmetry of all known laws of nature and the
existence of arrows of time that at all times and everywhere in the universe
all point in the same direction. I will argue that the failure may due to
unconscious application to the universe of the conceptual framework developed
for confined systems. If, as seems plausible, the universe is an unconfined
system, new concepts are needed.


title: Thermal dimension of quantum spacetime

abstract:
  Recent results suggest that a crucial crossroad for quantum gravity is the
characterization of the effective dimension of spacetime at short distances,
where quantum properties of spacetime become significant. This is relevant in
particular for various scenarios of "dynamical dimensional reduction" which
have been discussed in the literature. We are here concerned with the fact that
the related research effort has been based mostly on analyses of the "spectral
dimension", which involves an unphysical Euclideanization of spacetime and is
highly sensitive to the off-shell properties of a theory. As here shown,
different formulations of the same physical theory can have wildly different
spectral dimension. We propose that dynamical dimensional reduction should be
described in terms of the "thermal dimension" which we here introduce, a notion
that only depends on the physical content of the theory. We analyze a few
models with dynamical reduction both of the spectral dimension and of our
thermal dimension, finding in particular some cases where thermal and spectral
dimension agree, but also some cases where the spectral dimension has puzzling
properties while the thermal dimension gives a different and meaningful
picture.


title:
Stochastic forward-backward and primal-dual approximation algorithms
  with application to online image restoration

abstract:
  Stochastic approximation techniques have been used in various contexts in
data science. We propose a stochastic version of the forward-backward algorithm
for minimizing the sum of two convex functions, one of which is not necessarily
smooth. Our framework can handle stochastic approximations of the gradient of
the smooth function and allows for stochastic errors in the evaluation of the
proximity operator of the nonsmooth function. The almost sure convergence of
the iterates generated by the algorithm to a minimizer is established under
relatively mild assumptions. We also propose a stochastic version of a popular
primal-dual proximal splitting algorithm, establish its convergence, and apply
it to an online image restoration problem.


title: Recognizing Optimal 1-Planar Graphs in Linear Time

abstract:
  A graph with n vertices is 1-planar if it can be drawn in the plane such that
each edge is crossed at most once, and is optimal if it has the maximum of 4n-8
edges.
  We show that optimal 1-planar graphs can be recognized in linear time. Our
algorithm implements a graph reduction system with two rules, which can be used
to reduce every optimal 1-planar graph to an irreducible extended wheel graph.
The graph reduction system is non-deterministic, constraint, and non-confluent.


title:
Truthful Facility Assignment with Resource Augmentation: An Exact
  Analysis of Serial Dictatorship

abstract:
  We study the truthful facility assignment problem, where a set of agents with
private most-preferred points on a metric space are assigned to facilities that
lie on the metric space, under capacity constraints on the facilities. The goal
is to produce such an assignment that minimizes the social cost, i.e., the
total distance between the most-preferred points of the agents and their
corresponding facilities in the assignment, under the constraint of
truthfulness, which ensures that agents do not misreport their most-preferred
points.
  We propose a resource augmentation framework, where a truthful mechanism is
evaluated by its worst-case performance on an instance with enhanced facility
capacities against the optimal mechanism on the same instance with the original
capacities. We study a very well-known mechanism, Serial Dictatorship, and
provide an exact analysis of its performance. Although Serial Dictatorship is a
purely combinatorial mechanism, our analysis uses linear programming; a linear
program expresses its greedy nature as well as the structure of the input, and
finds the input instance that enforces the mechanism have its worst-case
performance. Bounding the objective of the linear program using duality
arguments allows us to compute tight bounds on the approximation ratio. Among
other results, we prove that Serial Dictatorship has approximation ratio
$g/(g-2)$ when the capacities are multiplied by any integer $g \geq 3$. Our
results suggest that even a limited augmentation of the resources can have
wondrous effects on the performance of the mechanism and in particular, the
approximation ratio goes to 1 as the augmentation factor becomes large. We
complement our results with bounds on the approximation ratio of Random Serial
Dictatorship, the randomized version of Serial Dictatorship, when there is no
resource augmentation.


title:
The electron-phonon coupling strength at metal surfaces directly
  determined from the Helium atom scattering Debye-Waller factor

abstract:
  A new quantum-theoretical derivation of the elastic and inelastic scattering
probability of He atoms from a metal surface, where the energy and momentum
exchange with the phonon gas can only occur through the mediation of the
surface free-electron density, shows that the Debye-Waller exponent is directly
proportional to the electron-phonon mass coupling constant $\lambda$. The
comparison between the values of $\lambda$ extracted from existing data on the
Debye-Waller factor for various metal surfaces and the $\lambda$ values known
from literature indicates a substantial agreement, which opens the possibility
of directly extracting the electron-phonon coupling strength in quasi-2D
conducting systems from the temperature or incident energy dependence of the
elastic Helium atom scattering intensities.


title: On the behavior of the size of a monomial ideal

abstract:
  In this paper we study the behavior of the size of a monomial ideal under
polarization and under generic deformations. As an application, we extend a
result relating the size and the Stanley depth of a squarefree monomial ideal
obtained by Herzog, Popescu and Vladoiu, together with a parallel result
obtained by Tang.


title:
Enhancement of Ultracold Molecule Formation Using Shaped Nanosecond
  Frequency Chirps

abstract:
  We demonstrate that judicious shaping of a nanosecond-time-scale frequency
chirp can dramatically enhance the formation rate of ultracold $^{87}$Rb$_{2}$
molecules. Starting with ultracold $^{87}$Rb atoms, we apply pulses of
frequency-chirped light to first photoassociate the atoms into excited
molecules and then, later in the chirp, de-excite these molecules into a high
vibrational level of the lowest triplet state, $a \, ^{3}\Sigma_{u}^{+}$. The
enhancing chirp shape passes through the absorption and stimulated emission
transitions relatively slowly, thus increasing their adiabaticity, but jumps
quickly between them to minimize the effects of spontaneous emission.
Comparisons with quantum simulations for various chirp shapes support this
enhancement mechanism.


title:
Nonequilibrium current-carrying steady states in the anisotropic $XY$
  spin chain

abstract:
  Out-of-equilibrium behavior is explored in the one-dimensional anisotropic
$XY$ model. Initially preparing the system in the isotropic $XX$ model with a
linearly varying magnetic field to create a domain-wall magnetization profile,
dynamics is generated by rapidly changing the exchange interaction anisotropy
and external magnetic field. Relaxation to a nonequilibrium steady state is
studied analytically at the critical transverse Ising point, where correlation
functions may be computed in closed form. For arbitrary values of anisotropy
and external field, an effective generalized Gibbs' ensemble is shown to
accurately describe observables in the long-time limit. Additionally, we find
spatial oscillations in the exponentially decaying, transverse spin-spin
correlation functions with wavelength set by the magnetization jump across the
initial domain wall. This wavelength depends only weakly on anisotropy and
magnetic field in contrast to the current, which is highly dependent on these
parameters.


title: Features of a high school olympiad problem

abstract:
  This paper is a supplement to a talk for mathematics teachers given at the
2016 LSU Mathematics Contest for High School Students. The paper covers more
details and aspects than could be covered in the talk.
  We start with an interesting problem from the 2009 Iberoamerican Math
Olympiad concerning a particular sequence. We include a solution to the
problem, but also relate it to several areas of mathematics. This problem
demonstrates the countability of the rational numbers with a direct one-to-one
correspondence. The problem also shows the one-to-one correspondence of finite
continued fractions and rational numbers. The subsequence of odd indexed terms
was constructed by Johannes Kepler and is discussed. We also show that the
indices have an extension to the 2-adic integers giving a one-to-one
correspondence between the positive real numbers and the 2-adic integers.
Everything but the extension to the 2-adic integers is known to have appeared
elsewhere.


title:
An algebraic approach to the KZ-functor for rational Cherednik algebras
  associated with cyclic groups

abstract:
  In the case of rational Cherednik algebras associated with cyclic groups, we
give an alternative proof that the projective object $P_{\text{KZ}}$
representing the KZ-functor is isomorphic to the $\Delta$-module associated
with the coinvariant algebra for a subset of parameter values from which all
parameter values can be obtained by integral translations. We also specify the
exact parameter values for which this isomorphism occurs. Furthermore, we
determine the action of the cyclotomic Hecke algebra on $P_{\text{KZ}}$ for
these parameter values, thereby giving a complete algebraic description of the
KZ-functor in this case.


title:
A Response to arXiv:1512.09181, "Space Charge Limits in the DAEdALUS DIC
  Compact Cyclotron"

abstract:
  This document addresses concerns raised about possible limits, due to space
charge, to the maximum H2+ ion beam current that can be injected into and
accepted by a compact cyclotron. The discussion of the compact cyclotron is
primarily within the context of the proposed DAEdALUS and IsoDAR neutrino
experiments. These concerns are examined by the collaboration and addressed
individually. While some of the concerns are valid, and present serious
challenges to the proposed program, the collaboration sees no immediate
showstoppers. However, some of the issues raised clearly need to be addressed
carefully--analytically, through simulation, and through experiments. In this
report, the matter is discussed, references are given to work already done and
future plans are outlined.


title:
Orbital magnetism of ultracold fermionic gases in a lattice: dynamical
  mean-field approach

abstract:
  We study finite-temperature properties of ultracold four-component mixtures
of alkaline-earth-like atoms in optical lattices that can be effectively
described by the two-band spin-$1/2$ Hubbard model including the Hund's
exchange coupling term. Our main goal is to investigate the effect of exchange
interactions on finite-temperature magnetic phases for a wide range of lattice
fillings. We use the dynamical mean-field theory approach and its real-space
generalization to obtain finite-temperature phase diagrams including
transitions to magnetically-ordered phases. It allows to determine optimal
experimental regimes for approaching long-range ferromagnetic ordering in
ultracold gases. We also calculate the entropy in the vicinity of
magnetically-ordered phases, which provides quantitative predictions for
on-going and future experiments aiming at approaching and studying long-range
ordered states in optical lattices.


title: Time-Space Trade-offs in Population Protocols

abstract:
  Population protocols are a popular model of distributed computing, in which
randomly-interacting agents with little computational power cooperate to
jointly perform computational tasks. Inspired by developments in molecular
computation, and in particular DNA computing, recent algorithmic work has
focused on the complexity of solving simple yet fundamental tasks in the
population model, such as leader election (which requires stabilization to a
single agent in a special "leader" state), and majority (in which agents must
stabilize to a decision as to which of two possible initial states had higher
initial count). Known results point towards an inherent trade-off between the
time complexity of such algorithms, and the space complexity, i.e. size of the
memory available to each agent.
  In this paper, we explore this trade-off and provide new upper and lower
bounds for majority and leader election. First, we prove a unified lower bound,
which relates the space available per node with the time complexity achievable
by a protocol: for instance, our result implies that any protocol solving
either of these tasks for $n$ agents using $O( \log \log n )$ states must take
$\Omega( n / \rm{polylog} n )$ expected time. This is the first result to
characterize time complexity for protocols which employ super-constant number
of states per node, and proves that fast, poly-logarithmic running times
require protocols to have relatively large space costs.
  On the positive side, we give algorithms showing that fast, poly-logarithmic
stabilization time can be achieved using $O( \log^2 n )$ space per node, in the
case of both tasks. Overall, our results highlight a time complexity separation
between $O(\log \log n)$ and $\Theta( \log^2 n )$ state space size for both
majority and leader election in population protocols, and introduce new
techniques, which should be applicable more broadly.


title:
Modeling Precursors for Event Forecasting via Nested Multi-Instance
  Learning

abstract:
  Forecasting events like civil unrest movements, disease outbreaks, financial
market movements and government elections from open source indicators such as
news feeds and social media streams is an important and challenging problem.
From the perspective of human analysts and policy makers, forecasting
algorithms need to provide supporting evidence and identify the causes related
to the event of interest. We develop a novel multiple instance learning based
approach that jointly tackles the problem of identifying evidence-based
precursors and forecasts events into the future. Specifically, given a
collection of streaming news articles from multiple sources we develop a nested
multiple instance learning approach to forecast significant societal events
across three countries in Latin America. Our algorithm is able to identify news
articles considered as precursors for a protest. Our empirical evaluation shows
the strengths of our proposed approaches in filtering candidate precursors,
forecasting the occurrence of events with a lead time and predicting the
characteristics of different events in comparison to several other
formulations. We demonstrate through case studies the effectiveness of our
proposed model in filtering the candidate precursors for inspection by a human
analyst.


title: Zero-Suppressed Computation: A New Computation Inspired by ZDDs

abstract:
  Zero-suppressed binary decision diagrams (ZDDs) are a data structure
representing Boolean functions, and one of the most successful variants of
binary decision diagrams (BDDs). On the other hand, BDDs are also called
branching programs in computational complexity theory, and have been studied as
a computation model. In this paper, we consider ZDDs from the viewpoint of
computational complexity theory. Our main proposal of this paper is that we
regard the basic idea of ZDDs as a new computation, which we call
zero-suppressed computation. We consider the zero-suppressed version of two
classical computation models, decision trees and branching programs, and show
some results. Although this paper is mainly written from the viewpoint of
computational complexity theory, the concept of zero-suppressed computation can
be widely applied to various areas.


title: Top Physics in WHIZARD

abstract:
  In this talk we summarize the top physics setup in the event generator
WHIZARD with a main focus on lepton colliders. This includes full six-, eight-
and ten-fermion processes, factorized processes and spin correlations. For
lepton colliders, QCD NLO processes for top quark physics are available and
will be discussed. A special focus is on the top-quark pair threshold, where a
special implementation combines a non-relativistic effective field theory
calculation augmented by a next-to-leading threshold logarithm resummation with
a continuum relativistic fixed-order QCD NLO simulation.


title: Thermodynamics of the $d$=3+1 Quantum XY Model

abstract:
  Within effective field theory we explore the properties of the $d$=3+1
quantum XY model at low temperatures and in weak magnetic or staggered fields.
For this parameter regime only few results appear to be known, and furthermore
are restricted to one-loop order. In the present study we systematically
analyze the thermodynamics of the $d$=3+1 quantum XY model up to three-loop
order. In the low-temperature expansion of the free energy density, the free
Bose gas term of order $T^4$ receives corrections of order $T^6$ and $T^8$. The
discussion also includes the pressure, (staggered) magnetization and
susceptibility. In particular, we show how these quantities are influenced by
the spin-wave interaction. We then compare our findings with those for the
quantum XY model in $d$=2+1.


title: ZAP -- Enhanced PCA Sky Subtraction for Integral Field Spectroscopy

abstract:
  We introduce Zurich Atmosphere Purge (ZAP), an approach to sky subtraction
based on principal component analysis (PCA) that we have developed for the
Multi Unit Spectrographic Explorer (MUSE) integral field spectrograph. ZAP
employs filtering and data segmentation to enhance the inherent capabilities of
PCA for sky subtraction. Extensive testing shows that ZAP reduces sky emission
residuals while robustly preserving the flux and line shapes of astronomical
sources. The method works in a variety of observational situations from sparse
fields with a low density of sources to filled fields in which the target
source fills the field of view. With the inclusion of both of these situations
the method is generally applicable to many different science cases and should
also be useful for other instrumentation. ZAP is available for download at
http://muse-vlt.eu/science/tools.


title: Regulator Artifacts in Uniform Matter for Chiral Interactions

abstract:
  Regulator functions applied to two- and three-nucleon forces are a necessary
ingredient in many-body calculations based on chiral effective field theory
interactions. These interactions have been developed recently with a variety of
different cutoff forms, including regulating both the momentum transfer (local)
and the relative momentum (nonlocal). While in principle any regulator that
suppresses high momentum modes can be employed, in practice artifacts are
inevitable in current power counting schemes. Artifacts from particular
regulators may cause significant distortions of the physics or may affect
many-body convergence rates, so understanding their nature is important. Here
we characterize the differences between cutoff effects using uniform matter at
Hartree-Fock and second-order in the interaction as a testbed. This provides a
clean laboratory to isolate phase-space effects of various regulators on both
two- and three-nucleon interactions. We test the normal-ordering approximation
for three-nucleon forces in nuclear matter and find that the relative size of
the residual 3N contributions is sensitive to the employed regularization
scheme.


title: A note on the notion "statistical symmetry"

abstract:
  A critical review is presented on the most recent attempt to generally
explain the notion of "statistical symmetry". This particular explanation,
however, is incomplete and misses one important and essential aspect. The aim
of this short note is to provide this missing information and to clarify this
notion on the basis of a few instructive examples.


title: SUSY Fits and their Implications for ILC and CLIC

abstract:
  We review results from our frequentist analysis of the parameter space of the
pMSSM10, in which the following 10 soft SUSY-breaking parameters are specified
independently at the mean scalar top mass scale Msusy = \sqrt{M_stop1 M_stop2}:
the gaugino masses M_{1,2,3}, the 1st-and 2nd-generation squark masses M_squ1 =
M_squ2, the third-generation squark mass M_squ3, a common slepton mass M_slep
and a common trilinear mixing parameter A, the Higgs mixing parameter mu, the
pseudoscalar Higgs mass M_A and tan beta, the ratio of the two Higgs vacuum
expectation values. We implemented the LHC searches for strongly- and
electroweakly-interacting sparticles and light stops, so as to confront the
pMSSM10 parameter space with all relevant SUSY searches. In addition, our
analysis includes Higgs mass and rate measurements, SUSY Higgs exclusion
bounds, the measurements of \bmm, other B-physics observables, electroweak
precision observables, the cold dark matter density and the searches for
spin-independent dark matter scattering, assuming that the cold dark matter is
mainly provided by the lightest neutralino. We discuss the discovery potential
of future e^+e^- linear colliders, such as ILC and CLIC, in the preferred
pMSSM10 parameter space.


title:
Neutral Higgs Boson Production at e^+e^- Colliders in the Complex MSSM:
  Towards the LC Precision

abstract:
  For the search for additional Higgs bosons in the Minimal Supersymmetric
Standard Model (MSSM) as well as for future precision analyses in the Higgs
sector a precise knowledge of their production properties is mandatory. We
review the evaluation of the cross sections for the neutral Higgs boson
production at e^+e^- colliders in the MSSM with complex parameters (cMSSM). The
evaluation is based on a full one-loop calculation of the production mechanisms
e^+e^- -> h_i Z, h_i gamma, h_i h_j (i,j = 1,2,3), including soft and hard QED
radiation. The dependence of the Higgs boson production cross sections on the
relevant cMSSM parameters is analyzed numerically. We find sizable
contributions to many cross sections. They are, depending on the production
channel, roughly of 10-20% of the tree-level results, but can go up to 50% or
higher.


title: Finite Element Method for Cosserat Plates

abstract:
  This paper presents the Finite Element Method for Cosserat plates. The
mathematical model for Cosserat elastic plates is based on the calculation of
the optimal value of the splitting parameter. We discuss the existence and
uniqueness of the weak solution and the convergence of the proposed FEM. The
Finite Element analysis of the clamped Cosserat plates of different shapes
under different loads is provided. We present the numerical validation of the
proposed FEM by estimating the order of convergence, when comparing the main
kinematic variables with the analytical solution. We also consider the
numerical analysis of plates with circular holes. We show that as expected the
stress concentration factor around the hole is smaller than the classical value
and smaller holes exhibit less stress concentration compared to larger ones.


title: The enhanced Sanov theorem and propagation of chaos

abstract:
  We establish a Sanov type large deviation principle for an ensemble of
interacting Brownian rough paths. As application a large deviations for the
($k$-layer, enhanced) empirical measure of weakly interacting diffusions is
obtained. This in turn implies a propagation of chaos result in rough path
spaces and allows for a robust subsequent analysis of the particle system and
its McKean-Vlasov type limit, as shown in two corollaries.


title:
On Adjusting the Learning Rate in Frequency Domain Echo Cancellation
  With Double-Talk

abstract:
  One of the main difficulties in echo cancellation is the fact that the
learning rate needs to vary according to conditions such as double-talk and
echo path change. In this paper we propose a new method of varying the learning
rate of a frequency-domain echo canceller. This method is based on the
derivation of the optimal learning rate of the NLMS algorithm in the presence
of noise. The method is evaluated in conjunction with the multidelay block
frequency domain (MDF) adaptive filter. We demonstrate that it performs better
than current double-talk detection techniques and is simple to implement.


title: PCA/LDA Approach for Text-Independent Speaker Recognition

abstract:
  Various algorithms for text-independent speaker recognition have been
developed through the decades, aiming to improve both accuracy and efficiency.
This paper presents a novel PCA/LDA-based approach that is faster than
traditional statistical model-based methods and achieves competitive results.
First, the performance based on only PCA and only LDA is measured; then a mixed
model, taking advantages of both methods, is introduced. A subset of the TIMIT
corpus composed of 200 male speakers, is used for enrollment, validation and
testing. The best results achieve 100%; 96% and 95% classification rate at
population level 50; 100 and 200, using 39-dimensional MFCC features with delta
and double delta. These results are based on 12-second text-independent speech
for training and 4-second data for test. These are comparable to the
conventional MFCC-GMM methods, but require significantly less time to train and
operate.


title:
Rashba spin-orbit coupling, strong interactions, and the BCS-BEC
  crossover in the ground state of the two-dimensional Fermi Gas

abstract:
  The recent experimental realization of spin-orbit coupled Fermi gases
provides a unique opportunity to study the interplay between strong interaction
and SOC in a tunable, disorder-free system. We present here precision ab initio
numerical results on the two-dimensional, unpolarized, uniform Fermi gas with
attractive interactions and Rashba SOC. Using auxiliary-field quantum Monte
Carlo and incorporating recent algorithmic advances, we carry out exact
calculations on sufficiently large system sizes to provide accurate results
systematically as a function of experimental parameters. We obtain the equation
of state, the momentum distributions, the pseudo-spin correlations and the
pairing wave functions. Our results help illuminate the rich pairing structure
induced by SOC, and provide benchmarks for theory and guidance to future
experimental efforts.


title: Towards Quantum Transport for Central Nuclear Reactions

abstract:
  Nonequilibrium Green's functions represent a promising tool for describing
central nuclear reactions. Even at the single-particle level, though, the
Green's functions contain more information that computers may handle in the
foreseeable future. In this study, we explore slab collisions in one dimension,
first in the mean field approximation and demonstrate that only function
elements close to the diagonal in arguments are relevant, in practice, for the
reaction calculations. This bodes well for the application of the Green's
functions to the reactions. Moreover we demonstrate that an initial state for a
reaction calculation may be generated through adiabatic transformation of
interactions. Finally, we report on our progress in incorporating correlations
into the dynamic calculations.


title: Denoising Flows on Trees

abstract:
  We study the estimation of flows on trees, a structured generalization of
isotonic regression. A tree flow is defined recursively as a positive flow
value into a node that is partitioned into an outgoing flow to the children
nodes, with some amount of the flow possibly leaking outside. We study the
behavior of the least squares estimator for flows, and the associated minimax
lower bounds. We characterize the risk of the least squares estimator in two
regimes. In the first regime the diameter of the tree grows at most
logarithmically with the number of nodes. In the second regime, the tree
contains long paths. The results are compared with known risk bounds for
isotonic regression.


title:
How to quantify coherence: Distinguishing speakable and unspeakable
  notions

abstract:
  Quantum coherence is a critical resource for many operational tasks.
Understanding how to quantify and manipulate it also promises to have
applications for a diverse set of problems in theoretical physics. For certain
applications, however, one requires coherence between the eigenspaces of
specific physical observables, such as energy, angular momentum, or photon
number, and it makes a difference which eigenspaces appear in the
superposition. For others, there is a preferred set of subspaces relative to
which coherence is deemed a resource, but it is irrelevant which of the
subspaces appear in the superposition. We term these two types of coherence
unspeakable and speakable respectively. We argue that a useful approach to
quantifying and characterizing unspeakable coherence is provided by the
resource theory of asymmetry when the symmetry group is a group of
translations, and we translate a number of prior results on asymmetry into the
language of coherence. We also highlight some of the applications of this
approach, for instance, in the context of quantum metrology, quantum speed
limits, quantum thermodynamics, and NMR. The question of how best to treat
speakable coherence as a resource is also considered. We review a popular
approach in terms of operations that preserve the set of incoherent states,
propose an alternative approach in terms of operations that are covariant under
dephasing, and we outline the challenge of providing a physical justification
for either approach. Finally, we note some mathematical connections that hold
among the different approaches to quantifying coherence.

categories: quant-ph cond-mat.dis-nn cond-mat.str-el cond-mat.supr-con nucl-th


title:
Dynamics of minimally coupled dark energy in spherical halos of dark
  matter

abstract:
  We analyse the evolution of scalar field dark energy in the spherical halos
of dark matter at the late stages of formation of gravitationally bound systems
in the expanding Universe. The dynamics of quintessential dark energy at the
center of dark matter halo strongly depends on the value of effective sound
speed $c_s$ (in units of speed of light). If $c_s\sim1$ (classical scalar
field) then the dark energy in the gravitationally bound systems is only
slightly perturbed and its density is practically the same as in cosmological
background. The dark energy with small value of sound speed ($c_s<0.1$), on the
contrary, is important dynamical component of halo at all stages of their
evolution: linear, non-linear, turnaround, collapse, virialization and later up
to current epoch. These properties of dark energy can be used for constraining
the value of effective sound speed $c_s$ by comparison the theoretical
predictions with observational data related to the large scale gravitationally
bound systems.


title: A trick to compute certain Manin products of operads

abstract:
  We describe simple tricks to compute the Manin black products with the
operads $\mathcal{A}ss$, $\mathcal{C}om$ and $pre\mathcal{L}ie$.


title:
Modelling stellar jets with magnetospheres using as initial states
  analytical MHD solutions

abstract:
  In this paper we focus on the construction of stellar outflow models emerging
from a polar coronal hole-type region surrounded by a magnetosphere in the
equatorial regions during phases of quiescent accretion. The models are based
on initial analytical solutions. We adopt a meridionally self-similar solution
of the time-independent and axisymmetric MHD equations which describes
effectively a jet originating from the corona of a star. We modify
appropriately this solution in order to incorporate a physically consistent
stellar magnetosphere. We find that the closed fieldline region may exhibit
different behaviour depending on the associated boundary conditions and the
distribution of the heat flux. However, the stellar jet in all final
equilibrium states is very similar to the analytical one prescribed in the
initial conditions. When the initial net heat flux is maintained, the
magnetosphere takes the form of a dynamical helmet streamer with a quasi steady
state slow magnetospheric wind. With no heat flux, a small dead zone forms
around the equator, surrounded by a weak streamer, source of a low mass flux
magnetospheric ejection. An equilibrium with no streamer and a helmet shaped
dead zone is found when the coronal hole is larger and extends up to a reduced
closed fieldline static zone. The study demonstrates the robustness of
self-similar solutions and their ability to provide quasi-steady jet
simulations with realistic boundaries and surrounded by equatorial
magnetospheres.


title: The young stellar population of Lynds 1340. An infrared view

abstract:
  We present results of an infrared study of the molecular cloud Lynds 1340,
forming three groups of low and intermediate-mass stars. Our goals are to
identify and characterise the young stellar population of the cloud, study the
relationships between the properties of the cloud and the emergent stellar
groups, and integrate L1340 into the picture of the star-forming activity of
our Galactic environment. We selected candidate young stellar objects from the
Spitzer and WISE data bases using various published color criteria, and
classified them based on the slope of the spectral energy distribution. We
identified 170 Class II, 27 Flat SED, and Class 0/I sources. High angular
resolution near-infrared observations of the RNO 7 cluster, embedded in L1340,
revealed eight new young stars of near-infrared excess. The surface density
distribution of young stellar objects shows three groups, associated with the
three major molecular clumps of L1340, each consisting of less than 100
members, including both pre-main sequence stars and embedded protostars. New
Herbig--Haro objects were identified in the Spitzer images. Our results
demonstrate that L1340 is a prolific star-forming region of our Galactic
environment in which several specific properties of the intermediate-mass mode
of star formation can be studied in detail.


title: Luminosity function of luminous compact star-forming galaxies

abstract:
  We study H-alpha, far- and near-ultraviolet luminosity functions (LF) of the
sample of 795 luminous compact star-forming galaxies with z<0.65. The
parameters of optimal functions for LFs are obtained using the maximum
likelihood method and the accuracy of fitting is estimated with the chi-squared
method. We find that these LFs cannot be reproduced by the Schechter function
because of an excess of very luminous galaxies. On the other hand, the Saunders
function, the log-normal distribution and some new related functions are good
approximations of LFs. The fact that LFs are not reproduced by the Schechter
function can be explained by the propagating star formation. This may result in
an excess of luminous starbursts with the mass of a young stellar population
above 2*10^8 M_Sun as compared to the LF of the quiescent galaxies. The most
luminous compact galaxies are characterised by H-alpha luminosities of >
5*10^{42} erg/s and star formation rates of > 40 M_Sun/yr.


title:
Stability of explicit one-step methods for P1-finite element
  approximation of linear diffusion equations on anisotropic meshes

abstract:
  We study the stability of explicit one-step integration schemes for the
linear finite element approximation of linear parabolic equations. The derived
bound on the largest permissible time step is tight for any mesh and any
diffusion matrix within a factor of $2(d+1)$, where $d$ is the spatial
dimension. Both full mass matrix and mass lumping are considered. The bound
reveals that the stability condition is affected by two factors. The first one
depends on the number of mesh elements and corresponds to the classic bound for
the Laplace operator on a uniform mesh. The other factor reflects the effects
of the interplay of the mesh geometry and the diffusion matrix. It is shown
that it is not the mesh geometry itself but the mesh geometry in relation to
the diffusion matrix that is crucial to the stability of explicit methods. When
the mesh is uniform in the metric specified by the inverse of the diffusion
matrix, the stability condition is comparable to the situation with the Laplace
operator on a uniform mesh. Numerical results are presented to verify the
theoretical findings.


title: Immobilization of a bubble in water by nanoelectrolysis

abstract:
  A surprising phenomenon is presented: a bubble, produced from water
electrolysis, is immobilized in the liquid (as if the Archimedes' buoyant force
were annihilated). This is achieved using a nanoelectrode (1 nm to 1 $\mu$m of
curvature radius at the apex) and an alternating electric potential with
adapted values of amplitude and frequency. A simple model based on
"nanoelectrolysis" (i.e., nanolocalization of the production of H2 and O2
molecules at the apex of the nanoelectrode) and an "open bubble" (i.e.,
exchanging H2 and O2 molecules with the solution) explains most of the
observations.


title: Biphoton statistic of quantum light generated on a silicon chip

abstract:
  We demonstrate a silicon-chip biphoton source with an unprecedented quantum
cross correlation up to ${\rm g_{si}^{(2)}(0) = (2.58 \pm 0.16) \times 10^4}$.
The emitted biphotons are intrinsically single-mode, with self correlations of
${\rm g_{ss}^{(2)}(0) = 1.90 \pm 0.05}$ and ${\rm g_{ii}^{(2)}(0) = 1.87 \pm
0.06}$ for signal and idler photons, respectively. We observe the waveform
asymmetry of cross correlation between signal and idler photons and reveal the
identical and non-exponential nature of self correlations of individual signal
and idler photon modes, which is a nature of cavity-enhanced nonlinear optical
processes. The high efficiency and high purity of the biphoton source allow us
to herald single photons with a conditional self correlation $\rm
g_{c}^{(2)}(0)$ as low as $\rm 0.0059 \pm 0.0014$ at a pair flux of $\rm 1.95
\times 10^5$ pairs/s, which remains below $\rm 0.026 \pm 0.001$ for a biphoton
flux up to $\rm 2.93 \times 10^6$ pairs/s, with a photon preparation efficiency
in the single-mode fiber up to 51%, among the best values that have ever been
reported. Our work unambiguously demonstrates that silicon photonic chips are
superior material and device platforms for integrated quantum photonics.


title: Evidence of s-wave superconductivity in ternary intermetallic La3Pd4Si4

abstract:
  We measured the temperature dependence of the magnetic penetration depth of
La3Pd4Si4 down to 0.02 Tc. We observe a temperature-independent behaviour below
0.25 Tc, which is firm evidence for a nodeless superconducting gap in this
material. The data display a very small anomaly around 1 K which we attribute
to the possible presence of a superconducting impurity phase. The superfluid
density is well described by a two-phase model, considering La3Pd4Si4 and the
impurity phase. The present analysis suggests that the superconducting energy
gap of La3Pd4Si4 is isotropic, as expected for conventional BCS
superconductors.


title: Finite time blowup for a supercritical defocusing nonlinear wave system

abstract:
  We consider the global regularity problem for defocusing nonlinear wave
systems $$ \Box u = (\nabla_{{\bf R}^m} F)(u) $$ on Minkowski spacetime ${\bf
R}^{1+d}$ with d'Alambertian $\Box := -\partial_t^2 + \sum_{i=1}^d
\partial_{x_i}^2$, the field $u: {\bf R}^{1+d} \to {\bf R}^m$ is vector-valued,
and $F: {\bf R}^m \to {\bf R}$ is a smooth potential which is positive and
homogeneous of order $p+1$ outside of the unit ball, for some $p >1$. This
generalises the scalar defocusing nonlinear wave (NLW) equation, in which $m=1$
and $F(v) = \frac{1}{p+1} |v|^{p+1}$. It is well known that in the energy
sub-critical and energy-critical cases when $d \leq 2$ or $d \geq 3$ and $p
\leq 1+\frac{4}{d-2}$, one has global existence of smooth solutions (for
dimensions $d \leq 7$ at least) from arbitrary smooth initial data $u(0),
\partial_t u(0)$. In this paper we study the supercritical case where $d = 3$
and $p > 5$. We show that in this case, there exists smooth potential $F$ for
some sufficiently large $m$ (in fact we can take $m=40$), positive and
homogeneous of order $p+1$ outside of the unit ball, and a smooth choice of
initial data $u(0), \partial_t u(0)$ for which the solution develops a finite
time singularity. In fact the solution is discretely self-similar in a
backwards light cone. The basic strategy is to first select the mass and energy
densities of $u$, then $u$ itself, and then finally design the potential $F$ in
order to solve the required equation. The Nash embedding theorem is used in the
second step, explaining the need to take $m$ relatively large.


title:
High-resolution magnetic penetration depth and inhomogeneities in
  locally noncentrosymmetric SrPtAs

abstract:
  We present a magnetic-penetration-depth study on polycrystalline and granular
samples of SrPtAs, a pnictide superconductor with a hexagonal structure
containing PtAs layers that individually break inversion symmetry (local
noncentrosymmetry). Compact samples show a clear-cut s-wave-type BCS behavior,
which we consider to be the intrinsic penetration depth of SrPtAs. Granular
samples display a sample-dependent second diamagnetic drop, attributed to the
intergrain coupling. Our experimental results point to a nodeless isotropic
superconducting energy gap in SrPtAs, which puts strong constraints on the
driven mechanism for superconductivity and the order parameter symmetry of this
compound.


title: Integrable Hopf twists, marginal deformations and generalised geometry

abstract:
  The Leigh-Strassler family of N=1 marginal deformations of the N=4 SYM theory
admits a Hopf algebra symmetry which is a quantum group deformation of the
SU(3) part of the R-symmetry of the Ncal=4 theory. We investigate how this
quantum symmetry might be expressed on the gravity side of the AdS/CFT
correspondence. First, we discuss the twist leading to the Hopf algebra
structure for the well-known beta-deformation as well as a unitarily equivalent
theory that we call the w-deformation. We then show how this Hopf twist can be
used to define a star product between the three scalar superfields of these
theories which encodes the deformed global symmetry. Turning to the gravity
side, we adapt this star product to deform the pure spinors of six-dimensional
flat space in its generalised geometry description. This leads to an N=2 NS-NS
solution of IIB supergravity. Starting from this precursor solution, adding
D3-branes and taking the near-horizon limit reproduces the dual gravitational
solution to the above theories, first derived by Lunin and Maldacena using TsT
techniques. This indicates that the Hopf algebra symmetry can play a useful
role in constructing the supergravity duals of the general Leigh-Strassler
deformations.


title: Probabilistic community detection with unknown number of communities

abstract:
  A fundamental problem in network analysis is clustering the nodes into groups
which share a similar connectivity pattern. Existing algorithms for community
detection assume the knowledge of the number of clusters or estimate it a
priori using various selection criteria and subsequently estimate the community
structure. Ignoring the uncertainty in the first stage may lead to erroneous
clustering, particularly when the community structure is vague. We instead
propose a coherent probabilistic framework for simultaneous estimation of the
number of communities and the community structure, adapting recently developed
Bayesian nonparametric techniques to network models. An efficient Markov chain
Monte Carlo (MCMC) algorithm is proposed which obviates the need to perform
reversible jump MCMC on the number of clusters. The methodology is shown to
outperform recently developed community detection algorithms in a variety of
synthetic data examples and in benchmark real-datasets. Using an appropriate
metric on the space of all configurations, we develop non-asymptotic Bayes risk
bounds even when the number of clusters is unknown. Enroute, we develop
concentration properties of non-linear functions of Bernoulli random variables,
which may be of independent interest.


title: Optimal Bounds for the No-Show Paradox via SAT Solving

abstract:
  Voting rules allow multiple agents to aggregate their preferences in order to
reach joint decisions. Perhaps one of the most important desirable properties
in this context is Condorcet-consistency, which requires that a voting rule
should return an alternative that is preferred to any other alternative by some
majority of voters. Another desirable property is participation, which requires
that no voter should be worse off by joining an electorate. A seminal result in
social choice theory by Moulin (1998) has shown that Condorcet-consistency and
participation are incompatible whenever there are at least 4 alternatives and
25 voters. We leverage SAT solving to obtain an elegant human-readable proof of
Moulin's result that requires only 12 voters. Moreover, the SAT solver is able
to construct a Condorcet-consistent voting rule that satisfies participation as
well as a number of other desirable properties for up to 11 voters, proving the
optimality of the above bound. We also obtain tight results for set-valued and
probabilistic voting rules, which complement and significantly improve existing
theorems.


title: Multipartite entanglement in heterogeneous systems

abstract:
  Heterogeneous bipartite quantum pure states, composed of two subsystems with
a different number of levels, cannot have both reductions maximally mixed. In
this work, we demonstrate existence of a wide range of highly entangled states
of heterogeneous multipartite systems consisting of $N>2$ parties such that
every reduction to one and two parties is maximally mixed. Two constructions of
generating genuinely multipartite maximally entangled states of heterogeneous
systems for an arbitrary number of subsystems are presented. Such states are
related to quantum error correction codes over mixed alphabets and mixed
orthogonal arrays. Additionally, we show the advantages of considering
heterogeneous systems in practical implementations of multipartite steering.


title:
Calibration of the EDGES High-Band Receiver to Observe the Global 21-cm
  Signature from the Epoch of Reionization

abstract:
  The EDGES High-Band experiment aims to detect the sky-average brightness
temperature of the $21$-cm signal from the Epoch of Reionization (EoR) in the
redshift range $14.8 \gtrsim z \gtrsim 6.5$. To probe this redshifted signal,
EDGES High-Band conducts single-antenna measurements in the frequency range
$90-190$ MHz from the Murchison Radio-astronomy Observatory in Western
Australia. In this paper, we describe the current strategy for calibration of
the EDGES High-Band receiver and report calibration results for the instrument
used in the $2015-2016$ observational campaign. We propagate uncertainties in
the receiver calibration measurements to the antenna temperature using a Monte
Carlo approach. We define a performance objective of $1$~mK residual RMS after
modeling foreground subtraction from a fiducial temperature spectrum using a
five-term polynomial. Most of the calibration uncertainties yield residuals of
$1$~mK or less at $95\%$ confidence. However, current uncertainties in the
antenna and receiver reflection coefficients can lead to residuals of up to
$20$ mK even in low-foreground sky regions. These dominant residuals could be
reduced by 1) improving the accuracy in reflection measurements, especially
their phase 2) improving the impedance match at the antenna-receiver interface,
and 3) decreasing the changes with frequency of the antenna reflection phase.


title:
Scalable semiparametric inference for the means of heavy-tailed
  distributions

abstract:
  Heavy tailed distributions present a tough setting for inference. They are
also common in industrial applications, particularly with Internet transaction
datasets, and machine learners often analyze such data without considering the
biases and risks associated with the misuse of standard tools. This paper
outlines a procedure for inference about the mean of a (possibly conditional)
heavy tailed distribution that combines nonparametric analysis for the bulk of
the support with Bayesian parametric modeling -- motivated from extreme value
theory -- for the heavy tail. The procedure is fast and massively scalable. The
resulting point estimators attain lowest-possible error rates and, unique among
alternatives, we are able to provide accurate uncertainty quantification for
these estimators. The work should find application in settings wherever correct
inference is important and reward tails are heavy; we illustrate the framework
in causal inference for A/B experiments involving hundreds of millions of users
of eBay.com.


title:
Improve Positioning Accuracy in WCDMA/FDD Networks Utilizing Adaptive
  Threshold for Direct Component Detection

abstract:
  In NLOS propagation conditions power of direct component can be attenuated
significantly. Therefore detection of direct component is aggravated which can
degrades accuracy of Time of Arrival mobile positioning. The goal of this paper
is to determine possibilities to improve estimation of direct component time
delay by reducing detection threshold. Three different methods for calculating
threshold has been tested and compared in terms of positioning error.