title:
A Framework for Accelerating Bottlenecks in GPU Execution with Assist
  Warps

abstract:
  Modern Graphics Processing Units (GPUs) are well provisioned to support the
concurrent execution of thousands of threads. Unfortunately, different
bottlenecks during execution and heterogeneous application requirements create
imbalances in utilization of resources in the cores. For example, when a GPU is
bottlenecked by the available off-chip memory bandwidth, its computational
resources are often overwhelmingly idle, waiting for data from memory to
arrive.
  This work describes the Core-Assisted Bottleneck Acceleration (CABA)
framework that employs idle on-chip resources to alleviate different
bottlenecks in GPU execution. CABA provides flexible mechanisms to
automatically generate "assist warps" that execute on GPU cores to perform
specific tasks that can improve GPU performance and efficiency.
  CABA enables the use of idle computational units and pipelines to alleviate
the memory bandwidth bottleneck, e.g., by using assist warps to perform data
compression to transfer less data from memory. Conversely, the same framework
can be employed to handle cases where the GPU is bottlenecked by the available
computational units, in which case the memory pipelines are idle and can be
used by CABA to speed up computation, e.g., by performing memoization using
assist warps.
  We provide a comprehensive design and evaluation of CABA to perform effective
and flexible data compression in the GPU memory hierarchy to alleviate the
memory bandwidth bottleneck. Our extensive evaluations show that CABA, when
used to implement data compression, provides an average performance improvement
of 41.7% (as high as 2.6X) across a variety of memory-bandwidth-sensitive GPGPU
applications.


title: On $J^{PC}=0^{--}$ exotic glueball

abstract:
  The mass spectrum of the gluonium with $J^{PC}=0^{--}$ is examined in three
bottom-up AdS/QCD models. The results are used to identify several production
and decay modes useful for searching this state. Moreover, the properties of
such glueball in a hot and dense quark medium are discussed.


title: Evidence for a Ru$^{4+}$ Kondo Lattice in LaCu$_3$Ru$_4$O$_{12}$

abstract:
  Rare $d$-electron derived heavy-fermion properties of the solid-solution
series LaCu$_3$Ru$_x$Ti$_{4-x}$O$_{12}$ were studied for $1 \leq x \leq 4$ by
resistivity, susceptibility, specific-heat measurements, and magnetic-resonance
techniques. The pure ruthenate ($x = 4$) is a heavy-fermion metal characterized
by a resistivity proportional to $T^2$ at low temperatures $T$. The coherent
Kondo lattice formed by the localized Ru 4$d$ electrons is screened by the
conduction electrons leading to strongly enhanced effective electron masses. By
increasing titanium substitution the Kondo lattice becomes diluted resulting in
single-ion Kondo properties like in the paradigm $4f$-based heavy-fermion
compound Ce$_x$La$_{1-x}$Cu$_{2.05}$Si$_2$ [M. Ocko {\em et al.}, Phys. Rev. B
\textbf{64}, 195106 (2001)]. In LaCu$_3$Ru$_x$Ti$_{4-x}$O$_{12}$ the
heavy-fermion behavior finally breaks down on crossing the metal-to-insulator
transition close to $x = 2$.


title:
Strong electroweak phase transition from Supersymmetric Custodial
  Triplets

abstract:
  The Supersymmetric Custodial Triplet Model, a supersymmetric generalization
of the Georgi-Machacek model, has proven to be an interesting modification of
the MSSM. It extends the MSSM Higgs sector by three extra SU(2)L triplets in
such a way that approximate custodial invariance is preserved and rho-parameter
deviations are kept under control. By means of a sizeable triplet contribution
to electroweak breaking the model is able to generate a barrier at tree level
between the false vacuum and the electroweak one. This will result in a strong
first order phase transition for an important region of the parameter space. We
also look at the gravitational waves that could be generated as a result of the
phase transition and show how future interferometers could be used as a probe
of the model.


title: Universality of causal graph dynamics

abstract:
  Causal Graph Dynamics generalize Cellular Automata, extending them to bounded
degree, time varying graphs. The dynamics rewrite the graph at each time step
with respect to two physics-like symmetries: causality (bounded speed of
information) and homogeneity (the rewriting acts the same everywhere on the
graph, at every time step). Universality is the ability simulating every other
instances of another (or the same) model of computation. In this work, we study
three different notions of simulation for Causal Graph Dynamics, each of them
leading to a definition of universality.


title:
Building a Bridge from Moments to PDF's: A New Approach to Finding PDF
  Mixing Models

abstract:
  Probability density function (PDF) methods are a promising alternative to
predicting the transport of solutes in groundwater under uncertainty. They make
it possible to derive the evolution equations of the mean concentration and the
concentration variance, used in moment methods. A mixing model, also known as a
dissipation model, is essential for both methods. Finding a satisfactory mixing
model is still an open question and due to the rather elaborate PDF methods, a
difficult undertaking. Both the PDF equation and the concentration variance
equation depend on the same mixing model. This connection is used to find and
test an improved mixing model for the much easier to handle concentration
variance. Subsequently, this mixing model is transferred to the PDF equation
and tested. The newly proposed mixing model yields significantly improved
results for both variance modelling and PDF modelling.


title: Gallium substitution in PuCoGa5

abstract:
  The substitution of gallium by aluminum, germanium, tin and indium in
PuCoGa5, the actinide-based superconductor with the highest critical
temperature, has been investigated. Only systems with 20% substitution by Al
and Ge (i.e. PuCoGa4Al and PuCoGa4Ge) have been successfully synthesized by
annealing arc-melted samples. X-ray powder diffraction refinements indicate an
enhanced c/a ratio in these two compounds but the magnetic susceptibility
measurements reveal a large reduction of the critical temperature Tc compared
to PuCoGa5. DFT+ED calculations indicate significant changes in the Fermi
surface, probably related to the decrease of Tc, in these compounds. In
addition, the isotopic effect of the atomic mass of gallium, using 69Ga and
71Ga isotopes, was also investigated without observable influence on the
critical temperature of PuCoGa5.


title:
Near-Optimality of Linear Recovery in Gaussian Observation Scheme under
  $\|\cdot\|_2^2$-Loss

abstract:
  We consider the problem of recovering linear image $Bx$ of a signal $x$ known
to belong to a given convex compact set $X$ from indirect observation
$\omega=Ax+\sigma\xi$ of $x$ corrupted by Gaussian noise $\xi$. It is shown
that under some assumptions on $X$ (satisfied, e.g., when $X$ is the
intersection of $K$ concentric ellipsoids/elliptic cylinders), an
easy-to-compute linear estimate is near-optimal, in certain precise sense, in
terms of its worst-case, over $x\in X$, expected $\|\cdot\|_2^2$-error. The
main novelty here is that our results impose no restrictions on $A$ and $B$, to
the best of our knowledge, preceding results on optimality of linear estimates
dealt either with the case of direct observations $A=I$ and $B=I$, or with the
"diagonal case" where $A$, $B$ are diagonal and $X$ is given by a "separable"
constraint like $X=\{x:\sum_ia_i^2x_i^2\leq 1\}$ or
$X=\{x:\max_i|a_ix_i|\leq1\}$, or with estimating a linear form (i.e., the case
one-dimensional $Bx$).


title: Chaotic and ballistic dynamics in time-driven quasiperiodic lattices

abstract:
  We investigate the nonequilibrium dynamics of classical particles in a driven
quasiperiodic lattice based on the Fibonacci sequence. An intricate transient
dynamics of extraordinarily long ballistic flights at distinct velocities is
found. We argue how these transients are caused and can be under- stood by a
hierarchy of block decompositions of the quasiperiodic lattice. A comparison to
the cases of periodic and fully randomized lattices is performed.


title: "Large" conformal metrics of prescribed Q-curvature in the negative case

abstract:
  Given a compact and connected four dimensional smooth Riemannian manifold
$(M,g_0)$ with $k_P := \int_M Q_{g_0} dV_{g_0} <0$ and a smooth non-constant
function $f_0$ with $\max_{p\in M}f_0(p)=0$, all of whose maximum points are
non-degenerate, we assume that the Paneitz operator is nonnegative and with
kernel consisting of constants. Then, we are able to prove that for
sufficiently small $\lambda>0$ there are at least two distinct conformal
metrics $g_\lambda=e^{2u_\lambda}g_0$ and $g^\lambda=e^{2u^\lambda}g_0$ of
$Q$-curvature $Q_{g_\lambda}=Q_{g^\lambda}=f_0+\lambda$. Moreover, by means of
the "monotonicity trick", we obtain crucial estimates for the "large" solutions
$u^\lambda$ which enable us to study their "bubbling behavior" as $\lambda
\downarrow 0$.


title: Towards Scalable Synthesis of Stochastic Control Systems

abstract:
  Formal control synthesis approaches over stochastic systems have received
significant attention in the past few years, in view of their ability to
provide provably correct controllers for complex logical specifications in an
automated fashion. Examples of complex specifications of interest include
properties expressed as formulae in linear temporal logic (LTL) or as automata
on infinite strings. A general methodology to synthesize controllers for such
properties resorts to symbolic abstractions of the given stochastic systems.
Symbolic models are discrete abstractions of the given concrete systems with
the property that a controller designed on the abstraction can be refined (or
implemented) into a controller on the original system. Although the recent
development of techniques for the construction of symbolic models has been
quite encouraging, the general goal of formal synthesis over stochastic control
systems is by no means solved. A fundamental issue with the existing techniques
is the known "curse of dimensionality," which is due to the need to discretize
state and input sets and that results in an exponential complexity over the
number of state and input variables in the concrete system. In this work we
propose a novel abstraction technique for incrementally stable stochastic
control systems, which does not require state-space discretization but only
input set discretization, and that can be potentially more efficient (and thus
scalable) than existing approaches. We elucidate the effectiveness of the
proposed approach by synthesizing a schedule for the coordination of two
traffic lights under some safety and fairness requirements for a road traffic
model. Further we argue that this 5-dimensional linear stochastic control
system cannot be studied with existing approaches based on state-space
discretization due to the very large number of generated discrete states.


title: Thermodynamics of Asymptotically Flat Black Holes in Lovelock Background

abstract:
  We study the thermodynamics of the asymptotically flat static black hole in
Lovelock back ground where the coupling constants of the Lovelock theory
effects are taken into account. We consider the effects of the second order of
the coupling constant, and third order of the Lovelock constant coefficient on
the thermodynamics of asymptotically flat static black holes. In this case the
effect of the coupling constants on the thermodynamics of the black hole are
discussed for 5, 6, and 7 dimensional spacetime.


title:
The role of band-index-dependent transport relaxation times in anomalous
  Hall effect

abstract:
  We revisit model calculations of the anomalous Hall effect (AHE) and show
that, in isotropic Rashba-coupled two-dimensional electron gas (2DEG) with
pointlike potential impurities, the full solution of the semiclassical
Boltzmann equation (SBE) may differ from the widely-used $1/\tau^{||}$ &
$1/\tau^{\perp}$ solution [Phys. Rev. B 68, 165311 (2003)]. Our approach to AHE
is analogous to the SBE-based analysis of the anisotropic magnetoresistance
leading to an integral equation for the distribution function [Phys. Rev. B 79,
045427 (2009)] but in the present case, we reduce the description to
band-index-dependent transport relaxation times. When both Rashba bands are
partially occupied, these are determined by solving a system of linear
equations. Detailed calculations show that, for intrinsic and hybrid skew
scatterings the difference between $1/\tau^{||}$ & $1/\tau^{\perp}$ and the
full solution of SBE is notable for large Fermi energies. For coordinate-shift
effects, the side-jump velocity acquired in the inter-band elastic scattering
process is shown to be more important for larger Rashba coupling and may even
exceed the intra-band one for the outer Rashba band. The coordinate-shift
contribution to AHE in the considered case notably differs from that in the
limit of smooth disorder potential analyzed before.


title:
Complexity of simple modules over the Lie superalgebra
  $\mathfrak{osp}(k|2)$

abstract:
  The complexity of a module is the rate of growth of the minimal projective
resolution of the module while the $z$-complexity is the rate of growth of the
number of indecomposable summands at each step in the resolution. Let
$\mathfrak{g}=\mathfrak{osp}(k|2)$ ($k>2$) be the type II orthosymplectic Lie
superalgebra of types $B$ or $D$. In this paper, we compute the complexity and
the $z$-complexity of the simple finite-dimensional
$\mathfrak{g}$-supermodules. We then give geometric interpretations using
support and associated varieties for these complexities.


title: Two-dimensional dispersion of magnetostatic volume spin waves

abstract:
  The dipolar (magnetostatic) interaction dominates the behavior of spin waves
in magnetic films in the long-wavelength regime. In an in-plane magnetized
film, volume modes exist with a negative group velocity (backward volume
magnetostatic spin waves), in addition to the forward surface-localized mode
(Damon-Eshbach). Inside the film of finite thickness $L$, the volume modes have
a nontrivial spatial dependence, and their two-dimensional dispersion relations
$\omega(\mathbf{k})$ can be calculated only numerically. We present explicit
perturbative expressions for the profiles and frequencies of the volume modes,
taking into account an in-plane applied field and uniaxial anisotropy, for the
regimes $\lVert \mathbf{k}L \rVert \gg 1$ and $\lVert \mathbf{k}L \rVert \ll
1$, which together provide a good indication of the behavior of the modes for
arbitrary wavevector $\mathbf{k}$. Moreover, we derive a very accurate
semianalytical expression for the dispersion relation $\omega(\mathbf{k})$ of
the lowest-frequency mode that is straightforward to evaluate using standard
numerical routines. Our results are useful to quickly interpret and control the
excitation and propagation of spin waves in (opto-)magnetic experiments.


title:
Geometrically induced complex tunnelings for ultracold atoms carrying
  orbital angular momentum

abstract:
  We investigate the dynamics of angular momentum states for a single ultracold
atom trapped in two dimensional systems of sided coupled ring potentials. The
symmetries of the system show that tunneling amplitudes between different ring
states with variation of the winding number are complex. In particular, we
demonstrate that in a triangular ring configuration the complex nature of the
cross-couplings can be used to geometrically engineer spatial dark states to
manipulate the transport of orbital angular momentum states via quantum
interference.


title:
The New Superconductor tP-SrPd2Bi2: Structural Polymorphism and
  Superconductivity in Intermetallics

abstract:
  We consider a system where structural polymorphism suggests the possible
existence of superconductivity through the implied structural instability.
SrPd2Bi2 has two poly-morphs which can be controlled by the synthesis
temperature: a tetragonal form (CaBe2Ge2-type) and a monoclinic form
(BaAu2Sb2-type). Though the crystallographic difference between the two forms
may at first seem trivial, we show that tetragonal SrPd2Bi2 is superconducting
at 2.0 K whereas monoclinic SrPd2Bi2 is not. We rationalize this finding and
place it in context with other 1-2-2 phases


title: On the Semantics of Intensionality

abstract:
  In this paper we propose a categorical theory of intensionality. We first
revisit the notion of intensionality, and discuss we its relevance to logic and
computer science. It turns out that 1-category theory is not the most
appropriate vehicle for studying the interplay of extension and intension. We
are thus led to consider the P-categories of \v{C}ubri\'{c}, Dybjer and Scott,
which are categories only up to a partial equivalence relation (PER). In this
setting, we introduce a new P-categorical construct, that of exposures.
Exposures are very nearly functors, except that they do not preserve the PERs
of the P-category. Inspired by the categorical semantics of modal logic, we
begin to develop their theory. Our leading examples demonstrate that an
exposure is an abstraction of well-behaved intensional devices, such as G\"odel
numberings. The outcome is a unifying framework in which classic results of
Kleene, G\"odel, Tarski and Rice find concise, clear formulations, and where
each logical device or assumption involved in their proofs can be expressed in
the same algebraic manner.


title: Semantic Acyclicity Under Constraints

abstract:
  A conjunctive query (CQ) is semantically acyclic if it is equivalent to an
acyclic one. Semantic acyclicity has been studied in the constraint-free case,
and deciding whether a query enjoys this property is NP-complete. However, in
case the database is subject to constraints such as tuple-generating
dependencies (tgds) that can express, e.g., inclusion dependencies, or
equality-generating dependencies (egds) that capture, e.g., functional
dependencies, a CQ may turn out to be semantically acyclic under the
constraints while not semantically acyclic in general. This opens avenues to
new query optimization techniques. In this paper we initiate and develop the
theory of semantic acyclicity under constraints. More precisely, we study the
following natural problem: Given a CQ and a set of constraints, is the query
semantically acyclic under the constraints, or, in other words, is the query
equivalent to an acyclic one over all those databases that satisfy the set of
constraints? We show that, contrary to what one might expect, decidability of
CQ containment is a necessary but not sufficient condition for the decidability
of semantic acyclicity. In particular, we show that semantic acyclicity is
undecidable in the presence of full tgds (i.e., Datalog rules). In view of this
fact, we focus on the main classes of tgds for which CQ containment is
decidable, and do not capture the class of full tgds, namely guarded,
non-recursive and sticky tgds. For these classes we show that semantic
acyclicity is decidable, and its complexity coincides with the complexity of CQ
containment. In the case of egds, we show that for keys over unary and binary
predicates semantic acyclicity is decidable (NP-complete). We finally consider
the problem of evaluating a semantically acyclic query over a database that
satisfies a set of constraints; for guarded tgds and functional dependencies
this problem is tractable.


title:
Superconducting quantum metamaterials as active lasing medium: Effects
  of disorder

abstract:
  A metamaterial formed by superconducting circuits or quantum dots can serve
as active lasing medium when coupled to a microwave resonator. For these
artificial atoms, in contrast to real atoms, variations in their parameters
cannot be avoided. In this paper, we examine the influence of disorder on such
a multi-atom lasing setup. We find that the lasing process evolves into a
self-organized stationary state that is quite robust against disorder. The
reason is that photons created by those atoms which are in or close to
resonance with the resonator stimulate the emission also of more detuned atoms.
Not only the number of photons grows with the number of atoms, but also the
width of the resonance as function of the detuning. Similar properties are
found for other types of disorder such as variations in the individual
coupling. We present relations how the allowed disorder scales with the number
of atoms and confirm it by a numerical analysis. We also provide estimates for
the sample-to-sample variations to be expected for setups with moderate numbers
of atoms.


title: Directly observing continuum emission from self-gravitating spiral waves

abstract:
  We use a simple, self-consistent, self-gravitating semi-analytic disc model
to conduct an examination of the parameter space in which self-gravitating
discs may exist. We then use Monte-Carlo radiative transfer to generate
synthetic ALMA images of these self-gravitating discs to determine the subset
of this parameter space in which they generate non-axisymmetric structure that
is potentially detectable by ALMA. Recently, several transition discs have been
observed to have non-axisymmetric structure that extends out to large radii. It
has been suggested that one possible origin of these asymmetries could be
spiral density waves induced by disc self-gravity. We use our simple model to
see if these discs exist in the region of parameter space where self-gravity
could feasibly explain these spiral features. We find that for self-gravity to
play a role in these systems typically requires a disc mass around an order of
magnitude higher than the observed disc masses for the systems. The spiral
amplitudes produced by self-gravity in the local approximation are relatively
weak when compared to amplitudes produced by tidal interactions, or spirals
launched at Lindblad resonances due to embedded planets in the disc. As such,
we ultimately caution against diagnosing spiral features as being due to
self-gravity, unless the disc exists in the very narrow region of parameter
space where the spiral wave amplitudes are large enough to produce detectable
features, but not so large as to cause the disc to fragment.


title: Type-II Topological Meissner States

abstract:
  We study the \emph{orbital effects} of the synthetic magnetic fields in an
interacting square lattice two-leg fermionic ladder model with the
number-conserving pair hopping that hosting the Majorana bound states. By
utilizing density matrix renormalization group and exact diagonalization, we
identify a novel type-II topological Meissner $($\emph{topo}-Meissner$)$ phase
$($as distinguished from the low-field type-I \emph{topo}-Meissner state$)$
when threading a \emph{high} magnetic flux through the plaquette of the ladder,
which not only exhibits a large uniformly circulating chiral current along the
legs, the characteristics of the celebrated Meissner state, but also
accommodates a topologically protected ground-state manifold due to the
\emph{reentrant} emergence of the Majorana end modes. Our work reveals some
interesting interference effects resulting from the interplay between the gauge
fields and the strong interactions in establishing the intrinsic topological
states of matter in low-dimensional quantum systems.


title: Sensory evaluation of commercial coffee brands in Colombia

abstract:
  Colombian coffee farmers have traditionally focused their efforts on
activities including seeding, planting and drying. Strategic issues to
successfully compete in the industry, such as branding, marketing and consumer
research, have been neglected. In this research, we apply a type of sensory
analysis, based on several statistical techniques used to investigate the key
features of ten different brands of Colombian coffee. A panel composed of 32
judges investigated nine different attributes related to flavour, fragrance,
sweetness and acidity, among others. The last section presents the conclusions
reached regarding customer preference and brands profiles.


title:
Analysis of generalized negative binomial distributions attached to
  hyperbolic Landau levels

abstract:
  To each hyperbolic Landau level of the Poincar\'e disc is attached a
generalized negative binomial distribution. In this paper, we compute the
moment generating function of this distribution and supply its decomposition as
a perturbation of the negative binomial distribution by a finitely-supported
measure. Using the Mandel parameter, we also discuss the nonclassical nature of
the associated coherent states. Next, we determine the L\'evy-Kintchine
decomposition its characteristic function when the latter does not vanish and
deduce that it is quasi-infinitely divisible except for the lowest hyperbolic
Landau level corresponding to the negative binomial distribution. By
considering the total variation of the obtained quasi-L\'evy measure, we
introduce a new infinitely-divisible distribution for which we derive the
characteristic function.


title: On Exclusive $h \to V \ell^+ \ell^-$ Decays

abstract:
  We study a set of exclusive decay modes of the Standard Model Higgs boson
into a vector meson and a dilepton pair: $h\to V \ell^+ \ell^-$, with
$V=\Upsilon, J/\psi,\phi$, and $\ell=\mu, \tau$, determining the decay rates,
the dilepton mass spectra and the $V$ longitudinal helicity fraction
distributions. In the same framework, we analyze the exclusive modes into
neutrino pairs $h\to V \nu \bar \nu$. We also discuss the implications of the
recent CMS and ATLAS results for the lepton flavor-changing process $h\to
\tau^+ \mu^-$ on the $h\to V \tau^+ \mu^-$ decay modes.


title:
Rigidity and characteristic classes of smooth bundles with nonpositively
  curved fibers

abstract:
  We prove vanishing results for the generalized Miller-Morita-Mumford classes
of some smooth bundles whose fiber is a closed manifold that supports a
nonpositively curved Riemannian metric. We also find, under some extra
conditions, that the vertical tangent bundle is topologically rigid.


title:
Long distance contributions to the rare kaon decay
  $K\to\pi\ell^{+}\ell^{-}$

abstract:
  The rare decays of a kaon into a pion and a charged lepton/antilepton pair
proceed via a flavour changing neutral current and therefore may only be
induced beyond tree level in the Standard Model. This natural suppression makes
these decays sensitive to the effects of potential New Physics. To discern such
New Physics one must be able to control the errors on the Standard Model
prediction of the decay amplitude. These particular decay channels however are
dominated by a single photon exchange; this involves a sizeable long-distance
hadronic contribution which represents the current major source of theoretical
uncertainty. Here we outline our methodology for the computation of the long
distance contributions to these rare decay amplitudes using lattice QCD, and
present the numerical results of some exploratory studies using the Domain Wall
Fermion ensembles of the RBC and UKQCD collaborations.


title: Holographic Equilibration of Nonrelativistic Plasmas

abstract:
  We study far-from-equilibrium physics of strongly interacting plasmas at
criticality and zero charge density for a wide range of dynamical scaling
exponents z in d dimensions using holographic methods. In particular, we
consider homogeneous isotropization of asymptotically Lifshitz black branes
with full backreaction. We find stable evolution and equilibration times that
exhibit small dependence of z and are of the order of the inverse temperature.
Performing a quasinormal mode analysis we find a corresponding narrow range of
relaxation times, fully characterized by the fraction z/(d-1). For z>=d-1,
equilibration is overdamped, whereas for z<d-1 we find oscillatory behavior.


title: Inv-ASKIT: A Parallel Fast Diret Solver for Kernel Matrices

abstract:
  We present a parallel algorithm for computing the approximate factorization
of an $N$-by-$N$ kernel matrix. Once this factorization has been constructed
(with $N \log^2 N $ work), we can solve linear systems with this matrix with $N
\log N $ work. Kernel matrices represent pairwise interactions of points in
metric spaces. They appear in machine learning, approximation theory, and
computational physics. Kernel matrices are typically dense (matrix
multiplication scales quadratically with $N$) and ill-conditioned (solves can
require 100s of Krylov iterations). Thus, fast algorithms for matrix
multiplication and factorization are critical for scalability.
  Recently we introduced ASKIT, a new method for approximating a kernel matrix
that resembles N-body methods. Here we introduce INV-ASKIT, a factorization
scheme based on ASKIT. We describe the new method, derive complexity estimates,
and conduct an empirical study of its accuracy and scalability. We report
results on real-world datasets including "COVTYPE" ($0.5$M points in 54
dimensions), "SUSY" ($4.5$M points in 8 dimensions) and "MNIST" (2M points in
784 dimensions) using shared and distributed memory parallelism. In our largest
run we approximately factorize a dense matrix of size 32M $\times$ 32M
(generated from points in 64 dimensions) on 4,096 Sandy-Bridge cores. To our
knowledge these results improve the state of the art by several orders of
magnitude.


title: A Flippon Related Singlet at the LHC II

abstract:
  We consider the 750 GeV diphoton resonance at the 13 TeV LHC in the ${\cal
F}$-$SU(5)$ model with a Standard Model (SM) singlet field which couples to
TeV-scale vector-like particles, dubbed $flippons$. This singlet field assumes
the role of the 750 GeV resonance, with production via gluon fusion and
subsequent decay to a diphoton via the vector-like particle loops. We present a
numerical analysis showing that the observed 8 TeV and 13 TeV diphoton
production cross-sections can be generated in the model space with realistic
electric charges and Yukawa couplings for light vector-like masses. We further
discuss the experimental viability of light vector-like masses in a General
No-Scale ${\cal F}$-$SU(5)$ model, offering a few benchmark scenarios in this
consistent GUT that can satisfy all experimental constraints imposed by the LHC
and other essential experiments.


title:
When are the Rees algebras of parameter ideals almost Gorenstein graded
  rings?

abstract:
  Let $A$ be a Cohen-Macaulay local ring with $\operatorname{dim} A = d\ge 3$,
possessing the canonical module ${\mathrm K}_A$. Let $a_1, a_2, \ldots, a_r$
$(3 \le r \le d)$ be a subsystem of parameters of $A$ and set $Q= (a_1, a_2,
\ldots, a_r)$. It is shown that if the Rees algebra ${\mathcal R}(Q)$ of $Q$ is
an almost Gorenstein graded ring, then $A$ is a regular local ring and $a_1,
a_2, \ldots, a_r$ is a part of a regular system of parameters of $A$.


title:
A bi-objective optimization framework for three-dimensional road
  alignment design

abstract:
  Optimization of three-dimensional road alignments is a nonlinear non-convex
optimization problem. The development of models that fully optimize a
three-dimensional road alignment problem is challenging due to numerous factors
involved and complexities in the geometric specification of the alignment. In
this study, we developed a novel bi-objective optimization approach to solve a
three dimensional road alignment problem where the horizontal and vertical
alignments are optimized simultaneously. Two conflicting cost objective
functions, \emph{earthwork} cost and the \emph{utility} cost, are cast in a
bi-objective optimization problem. We numerically compare several
multi-objective optimization solvers, and find that it is possible to determine
the Pareto front in a reasonable time.


title:
Entanglement entropy of excited states in conformal perturbation theory
  and the Einstein equation

abstract:
  For a conformal field theory (CFT) deformed by a relevant operator, the
entanglement entropy of a ball-shaped region may be computed as a perturbative
expansion in the coupling. A similar perturbative expansion exists for excited
states near the vacuum. Using these expansions, this work investigates the
behavior of excited state entanglement entropies of small, ball-shaped regions.
The motivation for these calculations is Jacobson's recent work on the
equivalence of the Einstein equation and the hypothesis of maximal vacuum
entropy [arXiv:1505.04753], which relies on a conjecture stating that the
behavior of these entropies is sufficiently similar to a CFT. In addition to
the expected type of terms which scale with the ball radius as $R^d$, the
entanglement entropy calculation gives rise to terms scaling as $R^{2\Delta}$,
where $\Delta$ is the dimension of the deforming operator. When
$\Delta\leq\frac{d}{2}$, the latter terms dominate the former, and suggest that
a modification to the conjecture is needed.


title:
Reactive two-body and three-body collisions of Ba$^+$ in an ultracold Rb
  gas

abstract:
  We analyze reactive collisions of a single Ba$^+$ ion in contact with an
ultracold gas of Rb atoms at low three-body collision energies of 2.2(9)
mK$\times k_{\mathrm{B}}$. Mapping out the Ba$^+$ loss rate dependence on the
Rb atom density we can discern two-body reactive collisions from three-body
ones and for the first time determine both rate coefficients which are
$k_2=3.1(6)(6)\times 10^{-13}\textrm{cm}^{3}\textrm{s}^{-1}$ and
$k_3=1.04(4)(45)\times 10^{-24}\textrm{cm}^{6}\textrm{s}^{-1}$, respectively
(statistical and systematic errors in parenthesis). Thus, the measured ternary
recombination dominates over binary reactions even at moderate atom densities
of $n\approx 10^{12}\: \textrm{cm}^{-3}$. The results for Ba$^+$ and Rb are
representative for a wide range of cold ion-atom systems and can serve as a
guidance for the future development of the field of hybrid atom-ion research.


title:
Hemisphere Partition Function and Analytic Continuation to the Conifold
  Point

abstract:
  We show that the hemisphere partition function for certain U(1) gauged linear
sigma models (GLSMs) with D-branes is related to a particular set of
Mellin-Barnes integrals which can be used for analytic continuation to the
singular point in the K\"ahler moduli space of an $h^{1,1}=1$ Calabi-Yau (CY)
projective hypersurface. We directly compute the analytic continuation of the
full quantum corrected central charge of a basis of geometric D-branes from the
large volume to the singular point. In the mirror language this amounts to
compute the analytic continuation of a basis of periods on the mirror CY to the
conifold point. However, all calculations are done in the GLSM and we do not
have to refer to the mirror CY. We apply our methods explicitly to the cubic,
quartic and quintic CY hypersurfaces.


title: Positive loops and $L^{\infty}$-contact systolic inequalities

abstract:
  We prove an inequality between the $L^{\infty}$-norm of the contact
Hamiltonian of a positive loop of contactomorphims and the minimal Reeb period.
This implies that there are no small positive loops on hypertight or Liouville
fillable contact manifolds. Non-existence of small positive loops for
overtwisted 3-manifolds was proved by Casals-Presas-Sandon in [CPS16].
  As corollaries of the inequality we deduce various results. E.g. we prove
that certain periodic Reeb flows are the unique minimizers of the
$L^\infty$-norm. Moreover, we establish $L^\infty$-type contact systolic
inequalities in the presence of a positive loop.


title: Analytic Continuation of Hypergeometric Functions in the Resonant Case

abstract:
  We perform the analytic continuation of solutions to the hypergeometric
differential equation of order $n$ to the third regular singularity, usually
denoted $z=1$, with the help of recurrences of their Mellin--Barnes integral
representations. In the resonant case, there are necessarily logarithmic
solutions. We apply the result to Picard-Fuchs equations of certain
one--parameter families of Calabi--Yau manifolds, known as the mirror quartic
and the mirror quintic.


title: The Minimum Shared Edges Problem on Planar Graphs

abstract:
  We study the Minimum Shared Edges problem introduced by Omran et al. [Journal
of Combinatorial Optimization, 2015] on planar graphs: Planar MSE asks, given a
planar graph G = (V,E), two distinct vertices s,t in V , and two integers p, k,
whether there are p s-t paths in G that share at most k edges, where an edges
is called shared if it appears in at least two of the p s-t paths. We show that
Planar MSE is NP-hard by reduction from Vertex Cover. We make use of a
grid-like structure, where the alignment (horizontal/vertical) of the edges in
the grid correspond to selection and validation gadgets respectively.


title: A Khovanov stable homotopy type for colored links

abstract:
  We extend Lipshitz-Sarkar's definition of a stable homotopy type associated
to a link L whose cohomology recovers the Khovanov cohomology of L. Given an
assignment c (called a coloring) of positive integer to each component of a
link L, we define a stable homotopy type X_col(L_c) whose cohomology recovers
the c-colored Khovanov cohomology of L. This goes via Rozansky's definition of
a categorified Jones-Wenzl projector P_n as an infinite torus braid on n
strands.
  We then observe that Cooper-Krushkal's explicit definition of P_2 also gives
rise to stable homotopy types of colored links (using the restricted palette
{1, 2}), and we show that these coincide with X_col. We use this equivalence to
compute the stable homotopy type of the (2,1)-colored Hopf link and the
2-colored trefoil. Finally, we discuss the Cooper-Krushkal projector P_3 and
make a conjecture of X_col(U_3) for U the unknot.


title: Unrestricted State Complexity of Binary Operations on Regular Languages

abstract:
  I study the state complexity of binary operations on regular languages over
different alphabets. It is well known that if $L'_m$ and $L_n$ are languages
restricted to be over the same alphabet, with $m$ and $n$ quotients,
respectively, the state complexity of any binary boolean operation on $L'_m$
and $L_n$ is $mn$, and that of the product (concatenation) is $(m-1)2^n
+2^{n-1}$. In contrast to this, I show that if $L'_m$ and $L_n$ are over their
own different alphabets, the state complexity of union and symmetric difference
is $mn+m+n+1$, that of intersection is $mn$, that of difference is $mn+m$, and
that of the product is $m2^n+2^{n-1}$.


title: Analyses of a Virtual World

abstract:
  We present an overview of a series of results obtained from the analysis of
human behavior in a virtual environment. We focus on the massive multiplayer
online game (MMOG) Pardus which has a worldwide participant base of more than
400,000 registered players. We provide evidence for striking statistical
similarities between social structures and human-action dynamics in the real
and virtual worlds. In this sense MMOGs provide an extraordinary way for
accurate and falsifiable studies of social phenomena. We further discuss
possibilities to apply methods and concepts developed in the course of these
studies to analyse oral and written narratives.


title: Constraining cosmic isotropy with type Ia supernovae

abstract:
  We investigate the validity of the Cosmological Principle by constraining the
cosmological parameters $H_0$ and $q_0$ through the celestial sphere. Our
analyses are performed in a low-redshift regime in order to follow a model
independent approach, using both Union2.1 and JLA Type Ia Supernovae (SNe)
compilations. We find that the preferred direction of the $H_0$ parameter in
the sky is consistent with the bulk flow motion of our local Universe in the
Union2.1 case, while the $q_0$ directional analysis seem to be anti-correlated
with the $H_0$ for both data sets. Furthermore, we test the consistency of
these results with Monte Carlo (MC) realisations, finding that the anisotropy
on both parameters are significant within $2-3\sigma$ confidence level, albeit
we find a significant correlation between the $H_0$ and $q_0$ mapping with the
angular distribution of SNe from the JLA compilation. Therefore, we conclude
that the detected anisotropies are either of local origin, or induced by the
non-uniform celestial coverage of the SNe data set.


title:
Assessing the role of nuclear effects in the interpretation of the
  MiniBooNE low-energy anomaly

abstract:
  We study the impact of the effect of multinucleon interactions in the
reconstruction of the neutrino energy on the fit of the MiniBooNE data in terms
of neutrino oscillations. We obtain some improvement of the fit of the
MiniBooNE low-energy excess in the framework of two-neutrino oscillations and a
shift of the allowed region in the $\sin^2 2\vartheta$--$\Delta{m}^2$ plane
towards smaller values of $\sin^2 2\vartheta$ and larger values of
$\Delta{m}^2$. However this effect is not enough to solve the problem of the
appearance-disappearance tension in the global fit of short-baseline neutrino
oscillation data.


title: The structure of large intersecting families

abstract:
  A collection of sets is {\em intersecting} if every two members have nonempty
intersection. We describe the structure of intersecting families of $r$-sets of
an $n$-set whose size is quite a bit smaller than the maximum ${n-1 \choose
r-1}$ given by the Erd\H os-Ko-Rado Theorem.
  In particular, this extends the Hilton-Milner theorem on nontrivial
intersecting families and answers a recent question of Han and Kohayakawa for
large $n$. In the case $r=3$ we describe the structure of all intersecting
families with more than 10 edges. We also prove a stability result for the
Erdos matching problem. Our short proofs are simple applications of the
Delta-system method introduced and extensively used by Frankl since 1977.


title: Particle identification in ALICE: a Bayesian approach

abstract:
  We present a Bayesian approach to particle identification (PID) within the
ALICE experiment. The aim is to more effectively combine the particle
identification capabilities of its various detectors. After a brief explanation
of the adopted methodology and formalism, the performance of the Bayesian PID
approach for charged pions, kaons and protons in the central barrel of ALICE is
studied. PID is performed via measurements of specific energy loss
($\mathrm{d}E/\mathrm{d}x$) and time-of-flight. PID efficiencies and
misidentification probabilities are extracted and compared with Monte Carlo
simulations using high-purity samples of identified particles in the decay
channels ${\rm K}^0_S \rightarrow \pi^-\pi^+$, $\phi \rightarrow {\rm K}^-{\rm
K}^+$, and $\Lambda \rightarrow {\rm p}\pi^-$ in p-Pb collisions at
$\sqrt{s_{\rm NN}}=5.02$ TeV. In order to thoroughly assess the validity of the
Bayesian approach, this methodology was used to obtain corrected $p_{\rm T}$
spectra of pions, kaons, protons, and D$^0$ mesons in pp collisions at
$\sqrt{s}=7$ TeV. In all cases, the results using Bayesian PID were found to be
consistent with previous measurements performed by ALICE using a standard PID
approach. For the measurement of D$^0 \rightarrow {\rm K}^-\pi^+$, it was found
that a Bayesian PID approach gave a higher signal-to-background ratio and a
similar or larger statistical significance when compared with standard PID
selections, despite a reduced identification efficiency. Finally, we present an
exploratory study of the measurement of $\Lambda_{\rm c}^{+}\rightarrow {\rm p}
{\rm K}^-\pi^+$ in pp collisions at $\sqrt{s}=7$ TeV, using the Bayesian
approach for the identification of its decay products.


title:
Ice Melt, Sea Level Rise and Superstorms: Evidence from Paleoclimate
  Data, Climate Modeling, and Modern Observations that 2{\deg}C Global Warming
  is Dangerous

abstract:
  We use numerical climate simulations, paleoclimate data, and modern
observations to study the effect of growing ice melt from Antarctica and
Greenland. Meltwater tends to stabilize the ocean column, inducing amplifying
feedbacks that increase subsurface ocean warming and ice shelf melting. Cold
meltwater and induced dynamical effects cause ocean surface cooling in the
Southern Ocean and North Atlantic, thus increasing Earth's energy imbalance and
heat flux into most of the global ocean's surface. Southern Ocean surface
cooling, while lower latitudes are warming, increases precipitation on the
Southern Ocean, increasing ocean stratification, slowing deepwater formation,
and increasing ice sheet mass loss. These feedbacks make ice sheets in contact
with the ocean vulnerable to accelerating disintegration. We hypothesize that
ice mass loss from the most vulnerable ice, sufficient to raise sea level
several meters, is better approximated as exponential than by a more linear
response. Doubling times of 10, 20 or 40 years yield multi-meter sea level rise
in about 50, 100 or 200 years. Recent ice melt doubling times are near the
lower end of the 10-40 year range, but the record is too short to confirm the
nature of the response. The feedbacks, including subsurface ocean warming, help
explain paleoclimate data and point to a dominant Southern Ocean role in
controlling atmospheric CO2, which in turn exercised tight control on global
temperature and sea level. The millennial (500-2000 year) time scale of deep
ocean ventilation affects the time scale for natural CO2 change and thus the
time scale for paleo global climate, ice sheet, and sea level changes, but this
paleo millennial time scale should not be misinterpreted as the time scale for
ice sheet response to a rapid large human-made climate forcing.


title:
A universal description of pseudorapidity distributions in both
  nucleus-nucleus and p-p collisions at now available energy regions

abstract:
  Investigations have shown that the collective motion not only appears in
nucleus-nucleus but also in p-p collisions. The best tool for depicting such
collective motion is relativistic hydrodynamics. In this paper, the collective
motion is assumed obeying the hydro model which integrates the features of
Landau and Hwa-Bjorken theory and is one of a very few analytically solvable
models. The fluid is then supposed freezing out into charged particles from a
time-like hypersurface with a fixed time of t_FO . The researches of present
paper show that this part of charged particles together with leading particles,
which, by conventional definition, carry on the quantum numbers of colliding
nucleons and take away the most part of incident energy, can give a proper
universal description to the pseudorapidity distributions of charged particles
measured in both nucleus-nucleus and p-p collisions at now available energy
regions.


title:
Interception efficiency of CVM-based lightning protection systems for
  buildings and the fractional Poisson model

abstract:
  The purpose of this paper is to resolve a question regarding efficiency of a
lightning protection system (LPS) for buildings based on the collection volume
method (CVM) . The paper has two components. The first, following suggestions
of other authors [Abidin and Ibrahim 2004], takes advantage of count data from
installed devices, and independent installation-site inspections to develop our
statistical analysis. The second component investigates the validity of the
underlying theory by introducing a novel methodology of fractional Poisson
processes, which are able to reproduce the burstiness of lightning strikes, an
essential feature of stochastic time dependence of incidence of lightning
strikes. The standard Poisson processes used in the past efforts in this area
cannot do that.


title: Making Walks Count: From Silent Circles to Hamiltonian Cycles

abstract:
  We illustrate the application of the matrix-transfer method for a number of
enumeration problems concerning the party game Silent Circles, Hamiltonian
cycles in the antiprism graphs, and simple paths and cycles of a fixed length
in arbitrary graphs.


title:
Mutual absolute continuity of interior and exterior harmonic measure
  implies rectifiability

abstract:
  We show that, for disjoint domains in the Euclidean space whose boundaries
satisfy a non-degeneracy condition, mutual absolute continuity of their
harmonic measures implies absolute continuity with respect to surface measure
and rectifiability in the intersection of their boundaries.


title:
Finding the different patterns in buildings data using bag of words
  representation with clustering

abstract:
  The understanding of the buildings operation has become a challenging task
due to the large amount of data recorded in energy efficient buildings. Still,
today the experts use visual tools for analyzing the data. In order to make the
task realistic, a method has been proposed in this paper to automatically
detect the different patterns in buildings. The K Means clustering is used to
automatically identify the ON (operational) cycles of the chiller. In the next
step the ON cycles are transformed to symbolic representation by using Symbolic
Aggregate Approximation (SAX) method. Then the SAX symbols are converted to bag
of words representation for hierarchical clustering. Moreover, the proposed
technique is applied to real life data of adsorption chiller. Additionally, the
results from the proposed method and dynamic time warping (DTW) approach are
also discussed and compared.


title:
$\Lambda_b \to \Lambda \ell^+ \ell^-$ form factors, differential
  branching fraction, and angular observables from lattice QCD with
  relativistic $b$ quarks

abstract:
  Using $(2+1)$-flavor lattice QCD, we compute the 10 form factors describing
the $\Lambda_b \to \Lambda$ matrix elements of the $b \to s$ vector, axial
vector, and tensor currents. The calculation is based on gauge field ensembles
generated by the RBC and UKQCD Collaborations with a domain-wall action for the
$u$, $d$, and $s$ quarks and the Iwasaki gauge action. The $b$ quark is
implemented using an anisotropic clover action, tuned nonperturbatively to the
physical point, and the currents are renormalized with a mostly nonperturbative
method. We perform simultaneous chiral, continuum, and kinematic extrapolations
of the form factors through modified $z$ expansions. Using our form factor
results, we obtain precise predictions for the $\Lambda_b \to \Lambda(\to p^+
\pi^-) \mu^+ \mu^-$ differential branching fraction and angular observables in
the Standard Model.


title: The Compact Star-Forming Complex at the Heart of NGC 253

abstract:
  We discuss integral field spectra of the compact star-forming complex that is
the brightest near-infrared (NIR) source in the central regions of the
starburst galaxy NGC 253. The spectra cover the H and K passbands and were
recorded with the Gemini NIR Spectrograph during sub-arcsec seeing conditions.
Absorption features in the spectrum of the star-forming complex are weaker than
in the surroundings. An absorption feature is found near 1.78um that coincides
with the location of a C2 bandhead. Emission lines of Brgamma, [FeII], and
HeI2.06um do not track the NIR continuum light. Pockets of star-forming
activity that do not have associated concentrations of red supergiants, and so
likely have ages < 8 Myr, are found along the western edge of the complex, and
there is evidence that one such pocket contains a rich population of Wolf-Rayet
stars. Unless the star-forming complex is significantly more metal-poor than
the surroundings, then a significant fraction of its total mass is in stars
with ages < 8 Myr. If the present-day star formation rate is maintained then
the time scale to double its stellar mass ranges from a few Myr to a few tens
of Myr, depending on the contribution made by stars older than ~ 8 Myr. If --
as suggested by some studies -- the star-forming complex is centered on the
galaxy nucleus, then the nucleus of NGC 253 is currently experiencing a phase
of rapid growth in its stellar mass.


title: Applications of AI for Magic Squares

abstract:
  In recreational mathematics, a normal magic square is an $n \times n$ square
matrix whose entries are distinctly the integers $1 \ldots n^2$, such that each
row, column, and major and minor traces sum to one constant $\mu$. It has been
proven that there are 7,040 fourth order normal magic squares and 2,202,441,792
fifth order normal magic squares, with higher orders unconfirmed. Previous work
related to fourth order normal squares has shown that symmetries such as the
dihedral group exist and that (under certain conditions) normal magic squares
can be categorized into four distinct subsets. With the implementation of an
efficient backtracking algorithm along with supervised machine learning
techniques for classification, it will be shown that the entire set of fourth
order normal magic squares can be generated by expanding the symmetry groups of
95 asymmetric parents. Discussion will suggest that methods employed in this
project could similarly apply to higher orders.


title: Chiral current generation in QED by longitudinal photons

abstract:
  We report the generation of a pseudovector electric current having imbalanced
chirality in an electron-positron strongly magnetized gas in QED. It propagates
along the external applied magnetic field B as a chiral magnetic effect in QED.
It is triggered by a perturbative electric field parallel to B, associated to a
pseudovector longitudinal mode propagating along B. An electromagnetic chemical
potential was introduced, but our results remain valid even for vanishing
chemical potential. A nonzero fermion mass was assumed, which is usually
considered vanishing in the literature. In the quantum field theory formalism
at finite temperature and density, an anomaly relation for the axial current
was found for a medium of massive fermions. It bears some analogy to the
Adler-Bell-Jackiw anomaly. From the expression for the chiral current in terms
of the photon self-energy tensor in a medium, it is obtained that electrons and
positrons scattered by longitudinal photons (inside the light cone) contribute
to the chiral current, as well as the pair creation due to longitudinal photons
(out of light cone). In the static limit, an electric pseudovector current is
obtained in the lowest Landau level


title: Equivariant differential operators on spinors in conformal geometry

abstract:
  We present a novel approach to the classification of conformally equivariant
differential operators on spinors in the case of homogeneous conformal
geometry. It is based on the classification of solutions for a vector-valued
system of partial differential equations, associated to $\mathcal{D}$-modules
for the homogeneous conformal structure and controlled by the spin Howe duality
for the orthogonal Lie algebras.


title: Quantum walks public key cryptographic system

abstract:
  Quantum Cryptography is a rapidly developing field of research that benefits
from the properties of Quantum Mechanics in performing cryptographic tasks.
Quantum walks are a powerful model for quantum computation and very promising
for quantum information processing. In this paper, we present a quantum
public-key cryptographic system based on quantum walks. In particular, in the
proposed protocol the public key is given by a quantum state generated by
performing a quantum walk. We show that the protocol is secure and analyze the
complexity of public-key generation and encryption/decryption procedures.


title: Invited Article: miniTimeCube

abstract:
  We present the development of the miniTimeCube (mTC), a novel compact
neutrino detector. The mTC is a multipurpose detector, aiming to detect not
only neutrinos but also fast/thermal neutrons. Potential applications include
the counterproliferation of nuclear materials and the investigation of
antineutrino short-baseline effects. The mTC is a plastic 0.2% $^{10}$B - doped
scintillator (13 cm)$^3$ cube surrounded by 24 Micro-Channel Plate (MCP) photon
detectors, each with an $8\times8$ anode totaling 1536 individual
channels/pixels viewing the scintillator. It uses custom-made electronics
modules which mount on top of the MCPs, making our detector compact and able to
both distinguish different types of events and reject noise in real time. The
detector is currently deployed and being tested at the National Institute of
Standards and Technology (NIST) Center for Neutron Research (NCNR) nuclear
reactor (20 MW$_\mathrm{th}$) in Gaithersburg, MD. A shield for further tests
is being constructed, and calibration and upgrades are ongoing. The mTC's
improved spatiotemporal resolution will allow for determination of incident
particle directions beyond previous capabilities.


title:
Optical conductivity of warm dense matter in wide frequency range within
  quantum statistical and kinetic approach

abstract:
  Fundamental properties of warm dense matter are described by the dielectric
function, which gives access to the frequency-dependent electrical
conductivity, absorption, emission and scattering of radiation, charged
particles stopping and further macroscopic properties. Different approaches to
the dielectric function and the related dynamical collision frequency are
compared in a wide frequency range. The high-frequency limit describing inverse
bremsstrahlung and the low-frequency limit of the dc conductivity are
considered. Sum rules and Kramers-Kronig relation are checked for the
generalized linear response theory and the standard approach following kinetic
theory. The results are discussed in application to aluminum, xenon and argon
plasmas.


title: A Kronecker-factored approximate Fisher matrix for convolution layers

abstract:
  Second-order optimization methods such as natural gradient descent have the
potential to speed up training of neural networks by correcting for the
curvature of the loss function. Unfortunately, the exact natural gradient is
impractical to compute for large models, and most approximations either require
an expensive iterative procedure or make crude approximations to the curvature.
We present Kronecker Factors for Convolution (KFC), a tractable approximation
to the Fisher matrix for convolutional networks based on a structured
probabilistic model for the distribution over backpropagated derivatives.
Similarly to the recently proposed Kronecker-Factored Approximate Curvature
(K-FAC), each block of the approximate Fisher matrix decomposes as the
Kronecker product of small matrices, allowing for efficient inversion. KFC
captures important curvature information while still yielding comparably
efficient updates to stochastic gradient descent (SGD). We show that the
updates are invariant to commonly used reparameterizations, such as centering
of the activations. In our experiments, approximate natural gradient descent
with KFC was able to train convolutional networks several times faster than
carefully tuned SGD. Furthermore, it was able to train the networks in 10-20
times fewer iterations than SGD, suggesting its potential applicability in a
distributed setting.


title:
Supraposinormality and hyponormality for the generalized Ces\`aro
  matrices of order two

abstract:
  It is well known that the generalized Ces\`aro matrices of order one are
hyponormal operators on $\ell^2$, and it has recently been shown that the
Ces\`aro matrix of order two is also hyponormal. Here the relatively new
concept of supraposinormality is used to show that the generalized Ces\`aro
matrices of order two are both posinormal and coposinormal, and that "most" of
them are also hyponormal. A conjecture is propounded that would extend the
hyponormality result.


title: Optimal De-Anonymization in Random Graphs with Community Structure

abstract:
  Anonymized social network graphs published for academic or advertisement
purposes are subject to de-anonymization attacks by leveraging side information
in the form of a second, public social network graph correlated with the
anonymized graph. This is because the two are from the same underlying graph of
true social relationships. In this paper, we (i) characterize the maximum a
posteriori (MAP) estimates of user identities for the anonymized graph and (ii)
provide sufficient conditions for successful de-anonymization for underlying
graphs with community structure. Our results generalize prior work that assumed
underlying graphs of Erd\H{o}s-R\'enyi type, in addition to proving the
optimality of the attack strategy adopted in the prior work.


title: A Framework for Fast Image Deconvolution with Incomplete Observations

abstract:
  In image deconvolution problems, the diagonalization of the underlying
operators by means of the FFT usually yields very large speedups. When there
are incomplete observations (e.g., in the case of unknown boundaries), standard
deconvolution techniques normally involve non-diagonalizable operators,
resulting in rather slow methods, or, otherwise, use inexact convolution
models, resulting in the occurrence of artifacts in the enhanced images. In
this paper, we propose a new deconvolution framework for images with incomplete
observations that allows us to work with diagonalized convolution operators,
and therefore is very fast. We iteratively alternate the estimation of the
unknown pixels and of the deconvolved image, using, e.g., an FFT-based
deconvolution method. This framework is an efficient, high-quality alternative
to existing methods of dealing with the image boundaries, such as edge
tapering. It can be used with any fast deconvolution method. We give an example
in which a state-of-the-art method that assumes periodic boundary conditions is
extended, through the use of this framework, to unknown boundary conditions.
Furthermore, we propose a specific implementation of this framework, based on
the alternating direction method of multipliers (ADMM). We provide a proof of
convergence for the resulting algorithm, which can be seen as a "partial" ADMM,
in which not all variables are dualized. We report experimental comparisons
with other primal-dual methods, where the proposed one performed at the level
of the state of the art. Four different kinds of applications were tested in
the experiments: deconvolution, deconvolution with inpainting, superresolution,
and demosaicing, all with unknown boundaries.


title: Intermediate links of plane curves

abstract:
  For a smooth complex curve C, we consider the link L(r) intersection of C
with the boundary of B(r), where B(r) denotes an Euclidean ball of radius r>0.
We prove that the diagram D(r) obtained from L(r) by a complex stereographic
projection satisfies that the Euler characteristic of the part of C in B(r)
equals the rotation number of D(r) minus the writhe of D(r). As a consequence
we show that if D(r) has no negative Seifert circles and L(r) is strongly
quasipositive and fibred, then the Yamada-Vogel algorithm applied to D(r)
yields a quasipositive braid.


title: Canary: A Scheduling Architecture for High Performance Cloud Computing

abstract:
  We present Canary, a scheduling architecture that allows high performance
analytics workloads to scale out to run on thousands of cores. Canary is
motivated by the observation that a central scheduler is a bottleneck for high
performance codes: a handful of multicore workers can execute tasks faster than
a controller can schedule them.
  The key insight in Canary is to reverse the responsibilities between
controllers and workers. Rather than dispatch tasks to workers, which then
fetch data as necessary, in Canary the controller assigns data partitions to
workers, which then spawn and schedule tasks locally.
  We evaluate three benchmark applications in Canary on up to 64 servers and
1,152 cores on Amazon EC2. Canary achieves up to 9-90X speedup over Spark and
up to 4X speedup over GraphX, a highly optimized graph analytics engine. While
current centralized schedulers can schedule 2,500 tasks/second, each Canary
worker can schedule 136,000 tasks/second per core and experiments show this
scales out linearly, with 64 workers scheduling over 120 million tasks per
second, allowing Canary to support optimized jobs running on thousands of
cores.


title:
Enhancement of radiative processes in nanofibers with embedded plasmonic
  nanoparticles

abstract:
  Efficient manipulation and long distance transport of single-photons is a key
component in nanoscale quantum optics. In this letter, we study the emission
properties of an individual light emitter placed into a nanofiber and coupled
to a metallic nanoparticle. We find that plasmonic field enhancement together
with the nanofiber optical confinement uniquely and synergistically contribute
to an overall increase of emission rates as well as quantum yields.


title:
Tracking the photodissociation probability of D$_2^+$ induced by
  linearly chirped laser pulses

abstract:
  In the presence of linearly varying frequency chirped laser pulses the
photodissociation dynamics of D$_2^+$ is studied theoretically after ionization
of D$_{2}$ . As a completion of our recent work (J. Chem. Phys. 143, 014305
(2015)) a comprehensive dependence on the pulse duration and delay time is
presented in terms of total dissociation probabilities. Our numerical analysis
carried out in the recently introduced light-induced conical intersection
(LICI) framework clearly shows the effects of the changing position of the LICI
which is induced by the frequency modulation of the chirped laser pulses. This
impact is presented for positively, negatively and zero chirped short pulses.


title:
The automorphism group of $M_{0,n}^\text{trop}$ and
  $\overline{M}_{0,n}^{\text{trop}}$

abstract:
  In this paper we show that the automorphism groups of $M_{0,n}^{\text{trop}}$
and $\overline{M}_{0,n}^{\text{trop}}$ are isomorphic to the permutation group
$S_n$ for $n\geq5$, while the automorphism groups of $M_{0,4}^{\text{trop}}$
and $\overline{M}_{0,4}^{\text{trop}}$ are isomorphic to the permutation group
$S_3$.


title: On the Relay-Fallback Tradeoff in Millimeter Wave Wireless System

abstract:
  Millimeter wave (mmWave) communications systems are promising candidate to
support extremely high data rate services in future wireless networks. MmWave
communications exhibit high penetration loss (blockage) and require directional
transmissions to compensate for severe channel attenuations and for high noise
powers. When blockage occurs, there are at least two simple prominent options:
1) switching to the conventional microwave frequencies (fallback option) and 2)
using an alternative non-blocked path (relay option). However, currently it is
not clear under which conditions and network parameters one option is better
than the other. To investigate the performance of the two options, this paper
proposes a novel blockage model that allows deriving maximum achievable
throughput and delay performance of both options. A simple criterion to decide
which option should be taken under which network condition is provided. By a
comprehensive performance analysis, it is shown that the right option depends
on the payload size, beam training overhead, and blockage probability. For a
network with light traffic and low probability of blockage in the direct link,
the fallback option is throughput- and delay-optimal. For a network with heavy
traffic demands and semi-static topology (low beam-training overhead), the
relay option is preferable.


title: Molecular cloud formation in high-shear, magnetized colliding flows

abstract:
  The colliding flows (CF) model is a well-supported mechanism for generating
molecular clouds. However, to-date most CF simulations have focused on the
formation of clouds in the normal-shock layer between head-on colliding flows.
We performed simulations of magnetized colliding flows that instead meet at an
oblique-shock layer. Oblique shocks generate shear in the post-shock
environment, and this shear creates inhospitable environments for star
formation. As the degree of shear increases (i.e. the obliquity of the shock
increases), we find that it takes longer for sink particles to form, they form
in lower numbers, and they tend to be less massive. With regard to magnetic
fields, we find that even a weak field stalls gravitational collapse within
forming clouds. Additionally, an initially oblique collision interface tends to
reorient over time in the presence of a magnetic field, so that it becomes
normal to the oncoming flows. This was demonstrated by our most oblique shock
interface, which became fully normal by the end of the simulation.


title: Twisted Yangians of small rank

abstract:
  We study quantized enveloping algebras called twisted Yangians associated
with the symmetric pairs of types CI, BDI and DIII (in Cartan's classification)
when the rank is small. We establish isomorphisms between these twisted
Yangians and the well known Olshanskii's twisted Yangians of types AI and AII,
and also with the Molev-Ragoucy reflection algebras associated with symmetric
pairs of type AIII. We also construct isomorphisms with twisted Yangians in
Drinfeld's original presentation.


title:
Liquid-Metal-Enabled Synthesis of Aluminum-Containing III-Nitrides by
  Plasma-Assisted Molecular Beam Epitaxy

abstract:
  Nitride films are promising for advanced optoelectronic and electronic device
applications. However, some challenges continue to impede development of high
aluminum-containing devices. The two major difficulties are growth of high
crystalline quality films with aluminum-rich compositions, and efficiently
doping such films p-type. These problems have severely limited use of
aluminum-rich nitride films grown by molecular beam epitaxy. A way around these
problems is through use of a liquid-metal-enabled approach to molecular beam
epitaxy. Although the presence of a liquid metal layer at the growth front is
reminiscent of conventional liquid phase epitaxy, this approach is different in
its details. Conventional liquid epitaxy is a near-thermodynamic equilibrium
process which liquid-metal assisted molecular beam epitaxy is not. Growth of
aluminum-rich nitrides is primarily driven by the kinetics of the molecular
vapor fluxes, and the surface diffusion of adatoms through a liquid metal layer
before incorporation. This paper reports on growth of high crystalline quality
and highly doped aluminum-containing nitride films. Measured optical and
electrical characterization data show that the approach is viable for growth of
atomically smooth aluminum-containing nitride heterostructures. Extremely high
p-type doping of up to $6 \times 10$$^{17}$ cm$^{-3}$ and n-type doping of up
to $1 \times 10$$^{20}$ cm$^{-3}$ in Al$_{0.7}$Ga$_{0.3}$N films was achieved.
Use of these metal-rich conditions is expected to have a significant impact on
high efficiency and high power optoelectronic and electronic devices that
require both high crystalline quality and highly doped (Al,Ga)N films.


title: Bidirectional imperfect quantum teleportation with a single Bell state

abstract:
  We present a bidirectional modification of the standard one-qubit
teleportation protocol, where both Alice and Bob transfer noisy versions of
their qubit states to each other by using single Bell state and auxiliary
(trigger) qubits. Three schemes are considered: the first where the actions of
parties are governed by two independent quantum random triggers, the second
with single random trigger, and the third as a mixture of the first two. We
calculate the fidelities of teleportation for all schemes and find a condition
on correlation between trigger qubits in the mixed scheme which allows us to
overcome the classical fidelity boundary of 2/3. We apply the Choi-Jamiolkowski
isomorphism to the quantum channels obtained in order to investigate an
interplay between their ability to transfer the information,
entanglement-breaking property, and auxiliary classical communication needed to
form correlations between trigger qubits. The suggested scheme for
bidirectional teleportation can be realized by using current experimental
tools.


title: An SSD-based eigensolver for spectral analysis on billion-node graphs

abstract:
  Many eigensolvers such as ARPACK and Anasazi have been developed to compute
eigenvalues of a large sparse matrix. These eigensolvers are limited by the
capacity of RAM. They run in memory of a single machine for smaller eigenvalue
problems and require the distributed memory for larger problems.
  In contrast, we develop an SSD-based eigensolver framework called FlashEigen,
which extends Anasazi eigensolvers to SSDs, to compute eigenvalues of a graph
with hundreds of millions or even billions of vertices in a single machine.
FlashEigen performs sparse matrix multiplication in a semi-external memory
fashion, i.e., we keep the sparse matrix on SSDs and the dense matrix in
memory. We store the entire vector subspace on SSDs and reduce I/O to improve
performance through caching the most recent dense matrix. Our result shows that
FlashEigen is able to achieve 40%-60% performance of its in-memory
implementation and has performance comparable to the Anasazi eigensolvers on a
machine with 48 CPU cores. Furthermore, it is capable of scaling to a graph
with 3.4 billion vertices and 129 billion edges. It takes about four hours to
compute eight eigenvalues of the billion-node graph using 120 GB memory.


title:
Influence of quantum confinement and strain on orbital polarization of
  four-layer LaNiO$_3$ superlattices: a DFT+DMFT study

abstract:
  Atomically precise superlattices involving transition metal oxides provide a
unique opportunity to engineer correlated electron physics using strain
(modulated by choice of substate) and quantum confinement (controlled by layer
thickness). Here we use the combination of density functional theory and
dynamical mean field theory (DFT+DMFT) to study Ni E$_g$ $d$-orbital
polarization in strained LaNiO$_3$/LaAlO$_3$ superlattices consisting of four
layers of nominally metallic NiO$_2$ and four layers of insulating AlO$_2$
separated by LaO layers. The layer-resolved orbital polarization is calculated
as a function of strain and analyzed in terms of structural, quantum
confinement, and correlation effects. The effect of strain is determined from
the dependence of the results on the Ni-O bond-length ratio and the octahedral
rotation angles; quantum confinement is studied by comparison to bulk
calculations with similar degrees of strain; correlation effects are inferred
by varying interaction parameters within our DFT+DMFT calculations. The
calculated dependence of orbital polarization on strain in superlattices is
qualitatively consistent with recent X-ray absorption spectroscopy and resonant
reflectometry data. However, interesting differences of detail are found
between theory and experiment. Under tensile strain, the two inequivalent Ni
ions display orbital polarization similar to that calculated for strained bulk
LaNiO$_3$ and observed in experiment. Compressive strain produces a larger
dependence of orbital polarization on Ni position and even the inner Ni layer
exhibits orbital polarization different from that calculated for strained bulk
LaNiO$_3$.


title:
Balanced growth path solutions of a Boltzmann mean field game model for
  knowledge growth

abstract:
  In this paper we study balanced growth path solutions of a Boltzmann mean
field game model proposed by Lucas et al [13] to model knowledge growth in an
economy. Agents can either increase their knowledge level by exchanging ideas
in learning events or by producing goods with the knowledge they already have.
The existence of balanced growth path solutions implies exponential growth of
the overall production in time. We proof existence of balanced growth path
solutions if the initial distribution of individuals with respect to their
knowledge level satisfies a Pareto-tail condition. Furthermore we give first
insights into the existence of such solutions if in addition to production and
knowledge exchange the knowledge level evolves by geometric Brownian motion.


title: The Sylow Subgroups of a Finite Reductive Group

abstract:
  We describe the structure of Sylow {\ell}-subgroups of a finite reduc-tive
group G(Fq) when q $\not\equiv$ 0 (mod {\ell}) that we find governed by a
complex reflection group attached to G and {\ell}, which depends on {\ell} only
through the set of cyclotomic factors of the generic order of G(Fq) whose value
at q is divisible by {\ell}. We also tackle the more general case G F where F
is an isogeny whose a power is a Frobenius morphism.


title: Geometric transformations of multidimensional color images based on NASS

abstract:
  We present quantum algorithms to realize geometric transformations (two-point
swappings, symmetric flips, local flips, orthogonal rotations, and
translations) based on an $n$-qubit normal arbitrary superposition state
(NASS). These transformations are implemented using quantum circuits consisting
of basic quantum gates, which are constructed with polynomial numbers of
single-qubit and two-qubit gates. Complexity analysis shows that the global
operators (symmetric flips, local flips, orthogonal rotations) can be
implemented with $O(n)$ gates. The proposed geometric transformations are used
to facilitate applications of quantum images with low complexity.


title: Roberge-Weiss endpoint at the physical point of $N_f = 2+1$ QCD

abstract:
  We study the phase diagram of $N_f = 2+1$ QCD in the $T - \mu_B$ plane and
investigate the critical point corresponding to the onset of the Roberge-Weiss
transition, which is found for imaginary values of $\mu_B$. We make use of
stout improved staggered fermions and of the tree level Symanzik gauge action,
and explore four different sets of lattice spacings, corresponding to $N_t =
4,6,8,10$, and different spatial sizes, in order to assess the universality
class of the critical point. The continuum extrapolated value of the endpoint
temperature is found to be $T_{\rm RW} = 208(5)$ MeV, i.e. $T_{\rm
  RW}/T_c \sim 1.34(7)$, where $T_c$ is the chiral pseudocritical temperature
at zero chemical potential, while our finite size scaling analysis, performed
on $N_t = 4$ and $N_t = 6$ lattices, provides evidence for a critical point in
the $3d$ Ising universality class.


title:
On estimates for the $\displaystyle \bar \partial $ equation in Stein
  manifolds

abstract:
  We generalize to intersection of strictly $c$ -convex domains in Stein
manifold, $ L^{r}-L^{s}$ and Lipschitz estimates for the solutions of the $
\bar \partial $ equation done by Ma and Vassiliadou for domains in $
{\mathbb{C}}^{n}.$ For this we use a Docquier-Grauert holomorphic retraction
plus the raising steps method I introduce earlier. This gives results in the
case of domains with low regularity, $ {\mathcal{C}}^{3},$ for their boundary.


title: "Draw My Topics": Find Desired Topics fast from large scale of Corpus

abstract:
  We develop the "Draw My Topics" toolkit, which provides a fast way to
incorporate social scientists' interest into standard topic modelling. Instead
of using raw corpus with primitive processing as input, an algorithm based on
Vector Space Model and Conditional Entropy are used to connect social
scientists' willingness and unsupervised topic models' output. Space for users'
adjustment on specific corpus of their interest is also accommodated. We
demonstrate the toolkit's use on the Diachronic People's Daily Corpus in
Chinese.


title: On Closed Manifolds with Harmonic Weyl Curvature

abstract:
  We derive point-wise and integral rigidity/gap results for a closed manifold
with harmonic Weyl curvature in any dimension. In particular, there is a
generalization of Tachibana's theorem for non-negative curvature operator. The
key ingredients are new Bochner-Weitzenb\"ock-Lichnerowicz type formulas for
the Weyl tensor, which are generalizations of identities in dimension four.


title: Unconditionally secure quantum coin flipping

abstract:
  Quantum coin flipping (QCF) is an essential primitive for quantum
cryptography. Unconditionally secure strong QCF with an arbitrarily small bias
was widely believed to be impossible. But basing on a problem which cannot be
solved without quantum algorithm, here we propose such a QCF protocol, and show
how it manages to evade all existing no-go proofs on QCF.


title: A heuristic for boundedness of ranks of elliptic curves

abstract:
  We present a heuristic that suggests that ranks of elliptic curves over the
rationals are bounded. In fact, it suggests that there are only finitely many
elliptic curves of rank greater than 21. Our heuristic is based on modeling the
ranks and Shafarevich-Tate groups of elliptic curves simultaneously, and relies
on a theorem counting alternating integer matrices of specified rank. We also
discuss analogues for elliptic curves over other global fields.


title:
Certain families of Polynomials arising in the study of hyperelliptic
  Lie algebras

abstract:
  The associative ring $R(P(t))=\mathbb C[t^{\pm1},u \,|\, u^2=P(t)]$, where
$P(t)=\sum_{i=0}^na_it^i=\prod_{k=1}^n(t-\alpha_i)$ with $\alpha_i\in\mathbb C$
pairwise distinct, is the coordinate ring of a hyperelliptic curve. The Lie
algebra $\mathcal{R}(P(t))=\text{Der}(R(P(t)))$ of derivations is called the
hyperelliptic Lie algebra associated to $P(t)$.
  In this paper we describe the universal central extension of
$\text{Der}(R(P(t)))$ in terms of certain families of polynomials which in a
particular case are associated Legendre polynomials. Moreover we describe
certain families of polynomials that arise in the study of the group of units
for the ring $R(P(t))$ where $P(t)=t^4-2bt^2+1$. In this study pairs of
Chebychev polynomials $(U_n,T_n)$ arise as particular cases of a pairs
$(r_n,s_n)$ with $r_n+s_n\sqrt{P(t)}$ a unit in $R(P(t))$. We explicitly
describe these polynomial pairs as coefficients of certain generating functions
and show certain of these polynomials satisfy particular second order linear
differential equations.


title: Metallicity from Type II Supernovae from the (i)PTF

abstract:
  Type IIP supernovae (SNe IIP) have recently been proposed as metallicity
($Z$) probes. The spectral models of Dessart et al. (2014) showed that the
pseudo-equivalent width of Fe II $\lambda$5018 (pEW$_{5018}$) during the
plateau phase depends on the primordial $Z$, but there was a paucity of SNe IIP
exhibiting pEW$_{5018}$ that were compatible with $Z < 0.4$ ${\rm Z}_{\odot}$.
This lack might be due to some physical property of the SN II population or to
the fact that those SNe have been discovered in luminous, metal-rich targeted
galaxies. Here we use SN II observations from the untargeted (intermediate)
Palomar Transient Factory [(i)PTF] survey, aiming to investigate the
pEW$_{5018}$ distribution of this SN population and, in particular, to look for
the presence of SNe II at lower $Z$. We perform pEW$_{5018}$ measurements on
the spectra of a sample of 39 (i)PTF SNe II, selected to have well-constrained
explosion epochs and light-curve properties. Based on the comparison with the
pEW$_{5018}$ spectral models, we subgrouped our SNe into four $Z$ bins from $Z
\approx 0.1$ $Z_{\odot}$ up to $Z \approx 2$ $Z_{\odot}$. We also independently
investigated the $Z$ of the hosts by using their absolute magnitudes and colors
and, in a few cases, using strong-line diagnostics from spectra. We searched
for possible correlations between SN observables, such as their peak magnitudes
and the $Z$ inferred from pEW$_{5018}$. We found 11 events with pEW$_{5018}$
that were small enough to indicate $Z \approx 0.1$ $Z_{\odot}$. The trend of
pEW$_{5018}$ with $Z$ matches the $Z$ estimates obtained from the host-galaxy
photometry, although the significance of the correlation is weak. We also found
that SNe with brighter peak magnitudes have smaller pEW$_{5018}$ and occur at
lower $Z$.


title: Stability of the Regular Hayward Thin-Shell Wormholes

abstract:
  The aim of this paper is to construct regular Hayward thin-shell wormholes
and analyze their stability. We adopt Israel formalism to calculate surface
stresses of the shell and check the null and weak energy conditions for the
constructed wormholes. It is found that the stress-energy tensor components
violate the null and weak energy conditions leading to the presence of exotic
matter at the throat. We analyze the attractive and repulsive characteristics
of wormholes corresponding to $a^r>0$ and $a^r<0$, respectively. We also
explore stability conditions for the existence of traversable thin-shell
wormholes with arbitrarily small amount of fluids describing cosmic expansion.
We find that the spacetime has non-physical regions which give rise to event
horizon for $0<a_{0}<2.8$ and the wormhole becomes non-traversable producing a
black hole. The non-physical region in the wormhole configuration decreases
gradually and vanishes for the Hayward parameter $l=0.9$. It is concluded that
the Hayward and Van der Waals quintessence parameters increase the stability of
thin-shell wormholes.


title: The Zero Active Mass Condition in Friedmann-Robertson-Walker Cosmologies

abstract:
  Many cosmological measurements today suggest that the Universe is expanding
at a constant rate. This is inferred from the observed age versus redshift
relationship and various distance indicators, all of which point to a cosmic
equation of state (EoS) p=-rho/3, where rho and p are, respectively, the total
energy density and pressure of the cosmic fluid. It has recently been shown
that this result is not a coincidence and simply confirms the fact that the
symmetries in the Friedmann-Robertson-Walker (FRW) metric appear to be viable
only for a medium with zero active mass, i.e., rho+3p=0. In their latest paper,
however, Kim, Lasenby and Hobson have provided what they believe to be a
counter argument to this conclusion. Here, we show that these authors are
merely repeating the conventional mistake of incorrectly placing the observer
simultaneously in a comoving frame, where the lapse function g_tt is coordinate
dependent when rho+3p is not 0, and a supposedly different, free-falling frame,
in which g_tt=1, implying no time dilation. We demonstrate that the Hubble flow
is not inertial when rho+3p is not 0, so the comoving frame is generally not in
free fall, even though in FRW, the comoving and free-falling frames are
supposed to be identical at every spacetime point. So this confusion of frames
not only constitutes an inconsistency with the fundamental tenets of general
relativity but, additionally, there is no possibility of using a gauge
transformation to select a set of coordinates for which g_tt=1 when rho+3p is
not 0.


title:
Roadless space is greatly diminished by logging in intact forest
  landscapes of the Congo Basin

abstract:
  Forest degradation in the tropics is often associated with roads built for
selective logging. The protection of Intact Forest Landscapes (IFL) that are
not accessible by roads is high on the biodiversity conservation agenda, a
challenge for logging concessions certified by the Forest Stewardship Council
(FSC). A frequently advocated conservation objective is to maximise the
retention of "roadless space", a concept that is based on distance to the
nearest road from any point. We developed a novel use of the empty space
function - a general statistical tool based on stochastic geometry and random
sets theory - to calculate roadless space in a part of the Congo Basin where
there has recently been rapid expansion of road networks. We compared the
temporal development of roadless space in certified and non-certified logging
concessions inside and outside areas declared as IFL in the year 2000. Between
1999 and 2007, rapid road network expansion led to a marked loss of roadless
space in IFL. After 2007, this trajectory levelled out in most areas, due to an
equilibrium between newly built roads and abandoned roads that became
revegetated. However, concessions within IFL that have been certified by FSC
since around 2007 showed continued decreases in roadless space, thus reaching a
level comparable to all other concessions. Only national parks remained
road-free. We recommend that forest management policies make the preservation
of large connected forest areas a top priority by effectively monitoring - and
limiting - the occupation of space by roads that are permanently accessible.


title: A Prototype Scalable Readout System for Micro-pattern Gas Detectors

abstract:
  A scalable readout system (SRS) is designed to provide a general solution for
different micro-pattern gas detectors. The system mainly consists of three
kinds of modules: the ASIC card, the Adapter card and the Front-End Card (FEC).
The ASIC cards, mounted with particular ASIC chips, are designed for receiving
detector signals. The Adapter card is in charge of digitizing the output
signals from several ASIC cards. The FEC, edged-mounted with the Adapter, has a
FPGA-based reconfigurable logic and I/O interfaces, allowing users to choose
various ASIC cards and Adapters for different types of detectors. The FEC
transfers data through Gigabit Ethernet protocol realized by a TCP processor
(SiTCP) IP core in field-programmable gate arrays (FPGA). The readout system
can be tailored to specific sizes to adapt to the experiment scales and readout
requirements. In this paper, two kinds of multi-channel ASIC chips, VA140 and
AGET, are applied to verify the concept of this SRS architecture. Based on this
VA140 or AGET SRS, one FEC covers 8 ASIC (VA140) cards handling 512 detector
channels, or 4 ASIC (AGET) cards handling 256 detector channels. More FECs can
be assembled in chassis to handle thousands of detector channels.


title: Comments on the Chernoff $\sqrt$ n-Lemma

abstract:
  The Chernoff $\sqrt$ n-Lemma is revised. This concerns two aspects: an
improvement of the Chernoff estimate in the strong operator topol-ogy and an
operator-norm estimate for quasi-sectorial contractions. Applications to the
Lie-Trotter product formula approximation for semigroups is presented.


title: Creating spacetime shortcuts with gravitational waveforms

abstract:
  A region-delimited gravitational wave field can be constructed, such that a
subset of geodesics crossing this region will move faster than nearby geodesics
moving entirely inside flat spacetime, along a preferred direction. Null
geodesics inside this region will move faster-than-light according to far away
observers. The waveform is synthesized from homogeneous plane wave solutions,
and the resulting field is the gravitational equivalent of a Gaussian beam.


title: Caract\`eres de repr\'esentations de niveau 0

abstract:
  Using the results of Meyer and Solleveld on the resolutions of Schneider and
Stuhler, we compute the character of every smooth representation of finite
length and of depht 0 of a p-adic group. We prove that, in every strongly
regular semi-simple point, the character is equal to some linear combination of
weighted orbital integrals.


title: Computational Security of Quantum Encryption

abstract:
  Quantum-mechanical devices have the potential to transform cryptography. Most
research in this area has focused either on the information-theoretic
advantages of quantum protocols or on the security of classical cryptographic
schemes against quantum attacks. In this work, we initiate the study of another
relevant topic: the encryption of quantum data in the computational setting.
  In this direction, we establish quantum versions of several fundamental
classical results. First, we develop natural definitions for private-key and
public-key encryption schemes for quantum data. We then define notions of
semantic security and indistinguishability, and, in analogy with the classical
work of Goldwasser and Micali, show that these notions are equivalent. Finally,
we construct secure quantum encryption schemes from basic primitives. In
particular, we show that quantum-secure one-way functions imply IND-CCA1-secure
symmetric-key quantum encryption, and that quantum-secure trapdoor one-way
permutations imply semantically-secure public-key quantum encryption.


title: Gender gap in the ERASMUS mobility program

abstract:
  Studying abroad has become very popular among students. The ERASMUS mobility
program is one of the largest international student exchange programs in the
world, which has supported already more than three million participants since
1987. We analyzed the mobility pattern within this program in 2011-12 and found
a gender gap across countries and subject areas. Namely, for almost all
participating countries, female students are over-represented in the ERASMUS
program when compared to the entire population of tertiary students. The same
tendency is observed across different subject areas. We also found a gender
asymmetry in the geographical distribution of hosting institutions, with a bias
of male students in Scandinavian countries. However, a detailed analysis
reveals that this latter asymmetry is rather driven by subject and consistent
with the distribution of gender ratios among subject areas.


title: Some Pairs Problems

abstract:
  A common form of MapReduce application involves discovering relationships
between certain pairs of inputs. Similarity joins serve as a good example of
this type of problem, which we call a "some-pairs" problem. In the framework of
Afrati et al. (VLDB 2013), algorithms are measured by the tradeoff between
reducer size (maximum number of inputs a reducer can handle) and the
replication rate (average number of reducers to which an input must be sent.
There are two obvious approaches to solving some-pairs problems in general. We
show that no general-purpose MapReduce algorithm can beat both of these two
algorithms in the worst case. We then explore a recursive algorithm for solving
some-pairs problems and heuristics for beating the lower bound on common
instances of the some-pairs class of problems.


title: Gromov hyperbolicity, the Kobayashi metric, and $\mathbb{C}$-convex sets

abstract:
  In this paper we study the global geometry of the Kobayashi metric on domains
in complex Euclidean space. We are particularly interested in developing
necessary and sufficient conditions for the Kobayashi metric to be Gromov
hyperbolic. For general domains, it has been suggested that a non-trivial
complex affine disk in the boundary is an obstruction to Gromov hyperbolicity.
This is known to be the case when the set in question is convex. In this paper
we first extend this result to $\mathbb{C}$-convex sets with $C^1$-smooth
boundary. We will then show that some boundary regularity is necessary by
producing in any dimension examples of open bounded $\mathbb{C}$-convex sets
where the Kobayashi metric is Gromov hyperbolic but whose boundary contains a
complex affine ball of complex codimension one.


title: Sequential Bayesian Analysis of Multivariate Count Data

abstract:
  We develop a new class of dynamic multivariate Poisson count models that
allow for fast online updating and we refer to these models as multivariate
Poisson-scaled beta (MPSB). The MPSB model allows for serial dependence in the
counts as well as dependence across multiple series with a random common
environment. Other notable features include analytic forms for state
propagation and predictive likelihood densities. Sequential updating occurs
through the updating of the sufficient statistics for static model parameters,
leading to a fully adapted particle learning algorithm and a new class of
predictive likelihoods and marginal distributions which we refer to as the
(dynamic) multivariate confluent hyper-geometric negative binomial distribution
(MCHG-NB) and the the dynamic multivariate negative binomial (DMNB)
distribution. To illustrate our methodology, we use various simulation studies
and count data on weekly non-durable goods consumer demand.


title: Unsupervised clustering of Type II supernova light curves

abstract:
  As new facilities come online, the astronomical community will be provided
with extremely large datasets of well-sampled light curves (LCs) of transient
objects. This motivates systematic studies of the light curves of supernovae
(SNe) of all types, including the early rising phase. We performed unsupervised
k-means clustering on a sample of 59 R-band Type II SN light curves and find
that our sample can be divided into three classes: slowly-rising (II-S),
fast-rise/slow-decline (II-FS), and fast-rise/fast-decline (II-FF). We also
identify three outliers based on the algorithm. We find that performing
clustering on the first two components of a principal component analysis gives
equivalent results to the analysis using the full LC morphologies. This may
indicate that Type II LCs could possibly be reduced to two parameters. We
present several important caveats to the technique, and find that the division
into these classes is not fully robust and is sensitive to the uncertainty on
the time of first light. Moreover these classes have some overlap, and are
defined in the R-band only. It is currently unclear if they represent distinct
physical classes, and more data is needed to study these issues. However, our
analysis shows that the outliers are actually composed of slowly-evolving SN
IIb, demonstrating the potential use of such methods. The slowly-evolving SNe
IIb may arise from single massive progenitors.


title:
Droplet formation near first-order phase transitions: A mechanism for
  heterogeneity and phase separation away from the coexistence curve

abstract:
  Phase separation, i.e., the coexistence of two different phases, is observed
in many systems away from the coexistence curve of a first-order transition,
leading to a stable heterogeneous phase or region. Examples include various
quantum ferromagnets, heavy-fermion systems, rare-earth nickelates, and others.
These observations seem to violate basic notions of equilibrium thermodynamics,
which state that phase separation can occur only on the coexistence curve. We
show theoretically that quenched disorder allows for phase separation away from
the coexistence curve even in equilibrium due to the existence of stable
minority-phase droplets within the majority phase. Our scenario also answers a
related question: How can a first-order transition remain sharp in the presence
of quenched disorder without violating the rigorous lower bound $\nu \geq 2/d$
for the correlation-length exponent? We discuss this scenario in the context of
experimental results for a large variety of systems.


title: SHARP: a distributed, GPU-based ptychographic solver

abstract:
  Ever brighter light sources, fast parallel detectors, and advances in phase
retrieval methods, have made ptychography a practical and popular imaging
technique. Compared to previous techniques, ptychography provides superior
robustness and resolution at the expense of more advanced and time consuming
data analysis. By taking advantage of massively parallel architectures,
high-throughput processing can expedite this analysis and provide microscopists
with immediate feedback. These advances allow real-time imaging at wavelength
limited resolution, coupled with a large field of view. Here, we introduce a
set of algorithmic and computational methodologies used at the Advanced Light
Source, and DOE light sources packaged as a CUDA based software environment
named SHARP (http://camera.lbl.gov/sharp), aimed at providing state-of-the-art
high-throughput ptychography reconstructions for the coming era of diffraction
limited light sources.