title:
Interference control of perfect photon absorption in cavity quantum
  electrodynamics

abstract:
  We propose and analyze a scheme for controlling coherent photon transmission
and reflection in a cavity-quantum-electrodynamics (CQED) system consisting of
an optical resonator coupled with three-level atoms coherently prepared by a
control laser from free space. When the control laser is off and the cavity is
excited by two identical light fields from two ends of the cavity, the two
input light fields can be completely absorbed by the CQED system and the light
energy is converted into the excitation of the polariton states, but no light
can escape from the cavity. Two distinct cases of controlling the perfect
photon absorption are analyzed: (a) when the control laser is tuned to the
atomic resonance and creates electromagnetically induced transparency, the
prefect photon absorption is suppressed and the input light fields are nearly
completely transmitted through the cavity; (b) when the control laser is tuned
to the polariton state resonance and inhibits the polariton state excitation,
the perfect photon absorption is again suppressed and the input light fields
are nearly completely reflected from the cavity. Thus, the CQED system can act
as a perfect absorber or near perfect transmitter/reflector by simply turning
off or on of the control laser. Such interference control of the coherent
photon-atom interaction in the CQED system should be useful for a variety of
applications in optical logical devices.


title: Multi-dimensional filtering: Reducing the dimension through rotation

abstract:
  Over the past few decades there has been a strong effort towards the
development of Smoothness-Increasing Accuracy-Conserving (SIAC) filters for
Discontinuous Galerkin (DG) methods, designed to increase the smoothness and
improve the convergence rate of the DG solution through this post-processor.
These advantages can be exploited during flow visualization, for example by
applying the SIAC filter to the DG data before streamline computations [Steffan
{\it et al.}, IEEE-TVCG 14(3): 680-692]. However, introducing these filters in
engineering applications can be challenging since a tensor product filter grows
in support size as the field dimension increases, becoming computationally
expensive. As an alternative, [Walfisch {\it et al.}, JOMP 38(2);164-184]
proposed a univariate filter implemented along the streamline curves. Until
now, this technique remained a numerical experiment. In this paper we introduce
the SIAC line filter and explore how the orientation, structure and filter size
affect the order of accuracy and global errors. We present theoretical error
estimates showing how line filtering preserves the properties of traditional
tensor product filtering, including smoothness and improvement in the
convergence rate. Furthermore, numerical experiments are included, exhibiting
how these filters achieve the same accuracy at significantly lower
computational costs, becoming an attractive tool for the scientific
visualization community.


title:
Gibbsian On-Line Distributed Content Caching Strategy for Cellular
  Networks

abstract:
  We develop Gibbs sampling based techniques for learning the optimal content
placement in a cellular network. A collection of base stations are scattered on
the space, each having a cell (possibly overlapping with other cells). Mobile
users request for downloads from a finite set of contents according to some
popularity distribution. Each base station can store only a strict subset of
the contents at a time; if a requested content is not available at any serving
base station, it has to be downloaded from the backhaul. Thus, there arises the
problem of optimal content placement which can minimize the download rate from
the backhaul, or equivalently maximize the cache hit rate. Using similar ideas
as Gibbs sampling, we propose simple sequential content update rules that
decide whether to store a content at a base station based on the knowledge of
contents in neighbouring base stations. The update rule is shown to be
asymptotically converging to the optimal content placement for all nodes. Next,
we extend the algorithm to address the situation where content popularities and
cell topology are initially unknown, but are estimated as new requests arrive
to the base stations. Finally, improvement in cache hit rate is demonstrated
numerically.


title: Multipoint scatterers with zero-energy bound states

abstract:
  We study multipoint scatterers with zero-energy bound states in three
dimensions. We present examples of such scatterers with multiple zero
eigenvalue or with strong multipole localization of zero-energy bound states.


title:
Kinetics of spontaneous filament nucleation via oligomers: insights from
  theory and simulation

abstract:
  Nucleation processes are at the heart of a large number of phenomena, from
cloud formation to protein crystallization. A recently emerging area where
nucleation is highly relevant is the initiation of filamentous protein
self-assembly, a process that has broad implications from medicine to
nanotechnology. As such, spontaneous nucleation of protein fibrils has received
much attention in recent years with many theoretical and experimental studies
focussing on the underlying physical principles. In this paper we make a step
forward in this direction and explore the early time behaviour of filamentous
protein growth in the context of nucleation theory. We first provide an
overview of the thermodynamics and kinetics of spontaneous nucleation of
protein filaments in the presence of one relevant degree of freedom, namely the
cluster size. In this case, we review how key kinetic observables, such as the
reaction order of spontaneous nucleation, are directly related to the physical
size of the critical nucleus. We then focus on the increasingly prominent case
of filament nucleation that includes a conformational conversion of the
nucleating building-block as an additional slow step in the nucleation process.
Using computer simulations, we study the concentration dependence of the
nucleation rate. We find that, under these circumstances, the reaction order of
spontaneous nucleation with respect to the free monomer does no longer relate
to the overall physical size of the nucleating aggregate but rather to the
portion of the aggregate that actively participates in the conformational
conversion. Our results thus provide a novel interpretation of the common
kinetic descriptors of protein filament formation, including the reaction order
of the nucleation step or the scaling exponent of lag times, and put into
perspective current theoretical descriptions of protein aggregation.


title:
On Polynomial Rings Over Nil Rings in Several Variables and the Central
  Closure of Prime Nil Rings

abstract:
  We prove that the ring of polynomials in several commuting indeterminates
over a nil ring cannot be homomorphically mapped onto a ring with identity,
i.e. it is Brown-McCoy radical. It answers a question posed by Puczylowski and
Smoktunowicz. We also show that the central closure of a prime nil ring cannot
be a simple ring with identity solving a problem due to Beidar.


title:
A testable radiative neutrino mass model without additional symmetries
  and Explanation for the $b \to s \ell^+ \ell^-$ anomaly

abstract:
  We propose a one-loop radiative Majorana-type neutrino-mass matrix without
any kind of additional symmetries by introducing two leptoquark-like bosons
only. In this scenario, we show that the anomaly appearing in the process $b\to
s\ell\bar\ell$ can be explained without any conflicts against various
constraints such as lepton-flavor violations, flavor-changing neutral currents,
oblique parameters $\Delta S,\ \Delta T$, and the Drell-Yan process. We make
the predictions for the flavor-violating lepton-pair production ($e\mu$,
$e\tau$, and $\mu\tau$) at the LHC, as well as the cross sections for pair
production of these leptoquark-like bosons.


title: Almost ISS property for feedback connected systems

abstract:
  Small-gain conditions used in analysis of feedback interconnections are
contraction conditions which imply certain stability properties. Such
conditions are applied to a finite or infinite interval. In this paper we
consider the case, when a small-gain condition is applied to several disjunct
intervals and use the density propagation condition in the gaps between these
intervals to derive global stability properties for an interconnection. This
extends and improves recent results from [1].


title: The Hoffmann-Jorgensen inequality in metric semigroups

abstract:
  We prove a refinement of the inequality by Hoffmann-Jorgensen that is
significant for three reasons. First, our result improves on the
state-of-the-art even for real-valued random variables. Second, the result
unifies several versions in the Banach space literature, including those by
Johnson and Schechtman [Ann. Probab. 17 (1989)], Klass and Nowicki [Ann.
Probab. 28 (2000)], and Hitczenko and Montgomery-Smith [Ann. Probab. 29
(2001)]. Finally, we show that the Hoffmann-Jorgensen inequality (including our
generalized version) holds not only in Banach spaces but more generally, in a
very primitive mathematical framework required to state the inequality: a
metric semigroup $\mathscr{G}$. This includes normed linear spaces as well as
all compact, discrete, or (connected) abelian Lie groups.


title: A criterion for left-orthogonality of an effective divisor on a surface

abstract:
  We find a criterion for an effective divisor $D$ on a smooth surface to be
left-orthogonal or strongly left-orthogonal (i.e. for the pair of line bundles
$(\mathcal O,\mathcal O(D))$ to be exceptional or strong exceptional).


title: A numerical study of interactions and stellar bars

abstract:
  For several decades it has been known that stellar bars in disc galaxies can
be triggered by interactions, or by internal processes such as dynamical
instabilities. In this work, we explore the differences between these two
mechanisms using numerical simulations. We perform two groups of simulations
based on isolated galaxies, one group in which a bar develops naturally, and
another group in which the bar could not develop in isolation. The rest of the
simulations recreate 1:1 coplanar fly-by interactions computed with the impulse
approximation. The orbits we use for the interactions represent the fly-bys in
groups or clusters of different masses accordingly to the velocity of the
encounter. In the analysis we focus on bars' amplitude, size, pattern speed and
their rotation parameter, ${\cal R}=R_{CR}/R_{bar}$. The latter is used to
define fast (${\cal R}<1.4$) and slow rotation (${\cal R}>1.4$). Compared with
equivalent isolated galaxies we find that bars affected or triggered by
interactions: (i) remain in the slow regime for longer; (ii) are more boxy in
face-on views; (iii) they host kinematically hotter discs. Within this set of
simulations we do not see strong differences between retrograde or prograde
fly-bys. We also show that slow interactions can trigger bar formation.


title: Causally consistent dynamic slicing

abstract:
  We offer a lattice-theoretic account of dynamic slicing for {\pi}-calculus,
building on prior work in the sequential setting. For any run of a concurrent
program, we exhibit a Galois connection relating forward slices of the start
configuration to backward slices of the end configuration. We prove that, up to
lattice isomorphism, the same Galois connection arises for any causally
equivalent execution, allowing an efficient concurrent implementation of
slicing via a standard interleaving semantics. Our approach has been formalised
in the dependently-typed language Agda.


title:
Polarization memory in the nonpolar magnetic ground state of
  multiferroic CuFeO2

abstract:
  We investigate polarization memory effects in single-crystal CuFeO2, which
has a magnetically-induced ferroelectric phase at low temperatures and applied
B fields between 7.5 and 13 T. Following electrical poling of the ferroelectric
phase, we find that the nonpolar collinear antiferromagnetic ground state at B
= 0 T retains a strong memory of the polarization magnitude and direction, such
that upon re-entering the ferroelectric phase a net polarization of comparable
magnitude to the initial polarization is recovered in the absence of external
bias. This memory effect is very robust: in pulsed-magnetic-field measurements,
several pulses into the ferroelectric phase with reverse bias are required to
switch the polarization direction, with significant switching only seen after
the system is driven out of the ferroelectric phase and ground state either
magnetically (by application of B > 13 T) or thermally. The memory effect is
also largely insensitive to the magnetoelastic domain composition, since no
change in the memory effect is observed for a sample driven into a
single-domain state by application of stress in the [1-10] direction. On the
basis of Monte Carlo simulations of the ground state spin configurations, we
propose that the memory effect is due to the existence of helical domain walls
within the nonpolar collinear antiferromagnetic ground state, which would
retain the helicity of the polar phase for certain magnetothermal histories.


title:
The National Science Foundation's AST Portfolio Review of 2012 is Not
  Relevant to the Green Bank Telescope of 2017: A White Paper

abstract:
  The National Science Foundation (NSF) Astronomy Division's Portfolio Review
of 2012 is no longer relevant to the Green Bank Telescope (GBT) of 2017 for two
principal reasons, one instrumental and the other astrophysical: 1) The GBT has
begun significant operations in the 3mm band, giving it unrivaled capabilities
for spectroscopy and continuum studies over 67-116 GHz. It is now an instrument
that is unique worldwide and is a critical complement to ALMA for the U.S.
scientific community. These capabilities had not been implemented at the time
of the review. 2) The detection of gravitational radiation by LIGO in 2015
places the GBT's work on pulsar observations of nano-Hz gravitational radiation
at the forefront of modern astrophysics.
  The Green Bank Telescope of 2017 is not the GBT that was reviewed by the
Eisenstein-Miller committee in 2012, a review that was specific to the NSF
Astronomy portfolio. The GBT serves a wide spectrum of science areas including
physics, chemistry, and planetary studies as well as astronomy. Besides its
well-documented intellectual merit, it thus has a significant broader impact.
The GBT is making significance advances in our understanding of gravitational
waves, the equation-of-state of nuclear matter, the mass of supermassive black
holes, the value of H0, and the physics of star-formation, all key science
goals for astronomy identified in a recent National Academy study "New Worlds,
New Horizons: A Midterm Assessment". In the era of ALMA and LIGO, other
countries have bolstered their mm-wave and cm-wave facilities; it is critical
that U.S. scientists have ready access to a large filled aperture to remain at
the forefront of research.


title: Colors of barlenses: evidence for connecting them to boxy/peanut bulges

abstract:
  We study the colors and orientations of structures in low and intermediate
inclination barred galaxies. We test the hypothesis that barlenses, roundish
central components embedded in bars, could form a part of the bar in a similar
manner to boxy/peanut bulges in the edge-on view. A sample of 79 barlens
galaxies was selected from the S$^4$G and the NIRS0S surveys. The sizes,
ellipticities, and orientations of barlenses were measured and used to define
the barlens regions in the color measurements. The orientations of barlenses
were studied with respect to those of the "thin bars" and the line-of-nodes of
the disks. For 47 galaxies color maps were constructed using the SDSS images in
five optical bands, u, g, r, i, and z. Colors of bars, barlenses, disks, and
central regions of the galaxies were measured using two different approaches
and color-color diagrams sensitive to metallicity, stellar surface gravity, and
short lived stars were constructed. Color differences between the structure
components were calculated for each individual galaxy, and presented in
histogram form. We find that the colors of barlenses are very similar to those
of the surrounding bars, indicating that most probably they form part of the
bar. We also find that barlenses have orientations closer to the disk
line-of-nodes than to the thin bars, which is consistent with the idea that
they are vertically thick, in a similar manner as the boxy/peanut structures in
more inclined galaxies. Typically, the colors of barlenses are similar to those
of normal E/S0 galaxies. Galaxy by galaxy studies show that in spiral galaxies
very dusty barlenses also exist, along with barlenses with rejuvenated stellar
populations. The central regions of galaxies are found to be on average redder
than bars or barlenses, although galaxies with bluer central peaks also exist.


title:
A staggered discontinuous Galerkin method for a class of nonlinear
  elliptic equations

abstract:
  In this paper, we present a staggered discontinuous Galerkin (SDG) method for
a class of nonlinear elliptic equations in two dimensions. The SDG methods have
some distinctive advantages, and have been successfully applied to a wide range
of problems including Maxwell equations, acoustic wave equation, elastodynamics
and incompressible Navier-Stokes equations. Among many advantages of the SDG
methods, one can apply a local post-processing technique to the solution, and
obtain superconvergence. We will analyze the stability of the method and derive
a priori error estimates. We solve the resulting nonlinear system using the
Newton's method, and the numerical results confirm the theoretical rates of
convergence and superconvergence.


title: Towards hybrid circuit quantum electrodynamics with quantum dots

abstract:
  Cavity quantum electrodynamics allows one to study the interaction between
light and matter at the most elementary level. The methods developed in this
field have taught us how to probe and manipulate individual quantum systems
like atoms and superconducting quantum bits with an exquisite accuracy. There
is now a strong effort to extend further these methods to other quantum
systems, and in particular hybrid quantum dot circuits. This could turn out to
be instrumental for a noninvasive study of quantum dot circuits and a
realization of scalable spin quantum bit architectures. It could also provide
an interesting platform for quantum simulation of simple fermion-boson
condensed matter systems. In this short review, we discuss the experimental
state of the art for hybrid circuit quantum electrodynamics with quantum dots,
and we present a simple theoretical modeling of experiments.


title: Application of Ontologies in Cloud Computing: The State-Of-The-Art

abstract:
  This paper presents a systematic survey on existing literature and seminal
works relevant to the application of ontologies in different aspects of Cloud
computing. Our hypothesis is that ontologies along with their reasoning
capabilities can have significant impact on improving various aspects of the
Cloud computing phenomena. Ontologies can promote intelligent decision support
mechanisms for various Cloud based services. They can also provide effective
interoperability among the Cloud based systems and resources. This survey can
promote a comprehensive understanding on the roles and significance of
ontologies within the overall domain of Cloud Computing. Also, this project can
potentially form the basis of new research area and possibilities for both
ontology and Cloud computing communities.


title: New dimension spectra: finer information on scaling and homogeneity

abstract:
  We introduce a new dimension spectrum motivated by the Assouad dimension; a
familiar notion of dimension which, for a given metric space, returns the
minimal exponent $\alpha\geq 0$ such that for any pair of scales $0<r<R$, any
ball of radius $R$ may be covered by a constant times $(R/r)^\alpha$ balls of
radius $r$. To each $\theta \in (0,1)$, we associate the appropriate analogue
of the Assouad dimension with the restriction that the two scales $r$ and $R$
used in the definition satisfy $\log R/\log r = \theta$. The resulting
`dimension spectrum' (as a function of $\theta$) thus gives finer geometric
information regarding the scaling structure of the space and, in some precise
sense, interpolates between the upper box dimension and the Assouad dimension.
This latter point is particularly useful because the spectrum is generally
better behaved than the Assouad dimension. We also consider the corresponding
`lower spectrum', motivated by the lower dimension, which acts as a dual to the
Assouad spectrum.
  We conduct a detailed study of these dimension spectra; including analytic,
geometric, and measureability properties. We also compute the spectra
explicitly for some common examples of fractals including decreasing sequences
with decreasing gaps and spirals with sub-exponential and monotonic winding. We
also give several applications of our results, including: dimension distortion
estimates under bi-H\"older maps for Assouad dimension and the provision of new
bi-Lipschitz invariants.


title: Impact of CP-violation on neutrino lepton number asymmetries revisited

abstract:
  We revisit the effect of the (Dirac) CP-violating phase on neutrino lepton
number asymmetries in both mass- and flavor-basis. We found that, even if there
are sizable effects on muon- and tau-neutrino asymmetries, the effect on the
asymmetry of electron-neutrinos is at most similar to the upper bound set by
BBN for initial neutrino degeneracy parameters smaller than order unity. We
also found that, for the asymmetries in mass-basis, the changes caused by
CP-violation is of sub-\% level which is unlikely to be accesible neither in
the current nor in the forthcoming experiments.


title:
Approximation Algorithms for Multi-Multiway Cut and Multicut Problems on
  Directed Graphs

abstract:
  In this paper, we present two approximation algorithms for the directed
multi-multiway cut and directed multicut problems. The so called region growing
paradigm \cite{1} is modified and used for these two cut problems on directed
graphs. By using this paradigm, we give for each problem an approximation
algorithm such that both algorithms have the approximate factor $O(k)$ the same
as the previous works done on these problems. However, the previous works need
to solve $k$ linear programming, whereas our algorithms require only one linear
programming. Therefore, our algorithms improve the running time of the previous
algorithms.


title:
Ballistic Anisotropic Magnetoresistance in Core Shell Nanowires and
  Rolled-up Nanotubes

abstract:
  In ferromagnetic nanostructures, the ballistic anisotropic magnetoresistance
(BAMR) is a change in the ballistic conductance with the direction of
magnetization due to spin-orbit interaction. Very recently, a directional
dependent ballistic conductance has been predicted to occur in a number of
newly synthesized nonmagnetic semiconducting nanostructures subject to
externally applied magnetic fields, without necessitating spin-orbit coupling.
In this article, we review past works on the prediction of this BAMR effect in
core-shell nanowires and rolled-up nanotubes. This is complemented by new
results we establish for the transport properties of tubular nanosystems
subject to external magnetic fields.


title:
The dynamical environment of asteroid 21 Lutetia according to different
  internal models

abstract:
  One of the most accurate models currently used to represent the gravity field
of irregular bodies is the polyhedral approach. In this model, the mass of the
body is assumed to be homogeneous, which may not be true for a real object. The
main goal of the present paper is to study the dynamical effects induced by
three different internal structures (uniform, three- and four-layers) of
asteroid (21) Lutetia, an object that recent results from space probe suggest
being at least partially differentiated. The Mascon gravity approach used in
the present work, consists of dividing each tetrahedron into eight parts to
calculate the gravitational field around the asteroid. The zero-velocity curves
show that the greatest displacement of the equilibrium points occurs in the
position of the E4 point for the four-layers structure and the smallest one
occurs in the position of the E3 point for the three-layers structure.
Moreover, stability against impact shows that the planar limit gets slightly
closer to the body with the four-layered structure.
  We then investigated the stability of orbital motion in the equatorial plane
of (21) Lutetia and propose numerical stability criteria to map the region of
stable motions. Layered structures could stabilize orbits that were unstable in
the homogeneous model.


title: Privacy Preserving Linear Programming

abstract:
  With the rapid increase in computing, storage and networking resources, data
is not only collected and stored, but also analyzed. This creates a serious
privacy problem which often inhibits the use of this data. In this chapter, we
investigate and resolve the privacy issues in a fundamental optimization
problem -- linear programming (LP) which is formulated by data collected from
different parties. We first consider the case where the objective function and
constraints of the linear programming problem are not partitioned between two
parties where one party privately holds the objective function while the other
party privately holds the constraints. Second, we present a privacy preserving
technique for the case that objective function and constraints are arbitrarily
partitioned between two parties where each party privately holds a share of
objective function and constraints. Finally, we extend the technique for
securely solving two-party arbitrarily partitioned linear programming problems
to a multi-party scenario. In summary, we propose a set of efficient and secure
transformation based techniques that create significant value-added benefits of
being independent of the specific algorithms used for solving the linear
programming problem.


title:
An infinite collection of quartic polynomials whose products of
  consecutive values are not perfect squares

abstract:
  Using an elementary identity, we prove that for infinitely many polynomials
$P(x)\in \mathbb{Z}[X]$ of fourth degree, the equation
$\prod\limits_{k=1}^{n}P(k)=y^2$ has finitely many solutions in $\mathbb{Z}$.
We also give an example of a quartic polynomial for which the product of it's
first consecutive values is infinitely often a perfect square.


title:
Pattern recognition in the ALFALFA.70 and Sloan Digital Sky Surveys: A
  catalog of $\sim$ 500,000 HI gas fraction estimates based on artificial
  neural networks

abstract:
  The application of artificial neural networks (ANNs) for the estimation of HI
gas mass fraction (\fgas) is investigated, based on a sample of 13,674 galaxies
in the Sloan Digital Sky Survey (SDSS) with HI detections or upper limits from
the Arecibo Legacy Fast Arecibo L-band Feed Array (ALFALFA). We show that, for
an example set of fixed input parameters ($g-r$ colour and $i$-band surface
brightness), a multidimensional quadratic model yields \fgas\ scaling relations
with a smaller scatter (0.22 dex) than traditional linear fits (0.32 dex),
demonstrating that non-linear methods can lead to an improved performance over
traditional approaches. A more extensive ANN analysis is performed using 15
galaxy parameters that capture variation in stellar mass, internal structure,
environment and star formation. Of the 15 parameters investigated, we find that
$g-r$ colour, followed by stellar mass surface density, bulge fraction and
specific star formation rate have the best connection with \fgas. By combining
two control parameters, that indicate how well a given galaxy in SDSS is
represented by the ALFALFA training set (\pr) and the scatter in the training
procedure (\sigf), we develop a strategy for quantifying which SDSS galaxies
our ANN can be adequately applied to, and the associated errors in the \fgas\
estimation. In contrast to previous works, our \fgas\ estimation has no
systematic trend with galactic parameters such as M$_{\star}$, $g-r$ and SFR.
We present a catalog of \fgas\ estimates for more than half a million galaxies
in the SDSS, of which $\sim$ 150,000 galaxies have a secure selection parameter
with average scatter in the \fgas\ estimation of 0.22 dex.


title:
Modeling the Spectra of Dense Hydrogen Plasmas: Beyond Occupation
  Probability

abstract:
  Accurately measuring the masses of white dwarf stars is crucial in many
astrophysical contexts (e.g., asteroseismology and cosmochronology). These
masses are most commonly determined by fitting a model atmosphere to an
observed spectrum; this is known as the spectroscopic method. However, for
cases in which more than one method may be employed, there are well known
discrepancies between masses determined by the spectroscopic method and those
determined by astrometric, dynamical, and/or gravitational-redshift methods. In
an effort to resolve these discrepancies, we are developing a new model of
hydrogen in a dense plasma that is a significant departure from previous
models. Experiments at Sandia National Laboratories are currently underway to
validate these new models, and we have begun modifications to incorporate these
models into stellar-atmosphere codes.


title:
Pure Connection Formulation, Twistors and the Chase for a Twistor Action
  for General Relativity

abstract:
  This paper establishes the relation between traditional results from
(euclidean) twistor theory and chiral formulations of General Relativity (GR),
especially the pure connection formulation. Starting from a $SU(2)$-connection
only we show how to construct natural complex data on twistor space, mainly an
almost Hermitian structure and a connection on some complex line bundle. Only
when this almost Hermitian structure is integrable is the connection related to
an anti-self-dual-Einstein metric and makes contact with the usual results.
This leads to a new proof of the non-linear-graviton theorem. Finally we
discuss what new strategies this "connection approach" to twistors suggests for
constructing a twistor action for gravity. In appendix we also review all known
chiral Lagrangians for GR.


title:
Engineering the Frequency Spectrum of Bright Squeezed Vacuum via Group
  Velocity Dispersion in an SU(1,1) Interferometer

abstract:
  Bright squeezed vacuum, a promising tool for quantum information, can be
generated by high-gain parametric down-conversion. However, its frequency and
angular spectra are typically quite broad, which is undesirable for
applications requiring single-mode radiation. We tailor the frequency spectrum
of high-gain parametric down-conversion using an SU(1,1) interferometer
consisting of two nonlinear crystals with a dispersive medium separating them.
The dispersive medium allows us to select a narrow band of the frequency
spectrum to be exponentially amplified by high-gain parametric amplification.
The frequency spectrum is thereby narrowed from (56.5 +- 0.1) to (1.22 +- 0.02)
THz and, in doing so, the number of frequency modes is reduced from
approximately 50 to 1.82 +- 0.02. Moreover, this method provides control and
flexibility over the spectrum of the generated light through the timing of the
pump.


title: Formation of metastable phases by spinodal decomposition

abstract:
  Metastable phases may be spontaneously formed from other metastable phases
through nucleation. Here we demonstrate the spontaneous formation of a
metastable phase from an unstable equilibrium by spinodal decomposition, which
leads to a transient coexistence of stable and metastable phases. This
phenomenon is generic within the recently introduced scenario of the
landscape-inversion phase transitions, which we experimentally realize as a
structural transition in a colloidal crystal. This transition exhibits a rich
repertoire of new phase-ordering phenomena, including the coexistence of two
equilibrium phases connected by two physically different interfaces. In
addition, this scenario enables the control of sizes and lifetimes of
metastable domains. Our findings open a new setting that broadens the
fundamental understanding of phase-ordering kinetics, and yield new prospects
of applications in materials science.


title:
Analysis of hadron yield data within hadron resonance gas model with
  multi-component eigenvolume corrections

abstract:
  We analyze the sensitivity of thermal fits to heavy-ion hadron yield data of
ALICE and NA49 collaborations to the systematic uncertainties in the hadron
resonance gas (HRG) model related to the modeling of the eigenvolume
interactions. We find a surprisingly large sensitivity in extraction of
chemical freeze-out parameters to the assumptions regarding eigenvolumes of
different hadrons. We additionally study the effect of including yields of
light nuclei into the thermal fits to LHC data and find even larger sensitivity
to the modeling of their eigenvolumes. The inclusion of light nuclei yields,
thus, may lead to further destabilization of thermal fits. Our results show
that modeling of eigenvolume interactions plays a crucial role in
thermodynamics of HRG and that conclusions based on a non-interacting HRG are
not unique.


title:
Critical Velocity in the Presence of Surface Bound States in Superfluid
  $^3$He-B

abstract:
  A microelectromechanical oscillator with a gap of 1.25 $\mu$m was immersed in
superfluid $^3$He-B and cooled below 250 $\mu$K at various pressures.
Mechanical resonances of its shear motion were measured at various levels of
driving force. The oscillator enters into a nonlinear regime above a certain
threshold velocity. The damping increases rapidly in the nonlinear region and
eventually prevents the velocity of the oscillator from increasing beyond the
critical velocity which is much lower than the Landau critical velocity. We
propose that this peculiar nonlinear behavior stems from the escape of
quasiparticles from the surface bound states into the bulk fluid.


title:
Adaptive Convolutional ELM For Concept Drift Handling in Online Stream
  Data

abstract:
  In big data era, the data continuously generated and its distribution may
keep changes overtime. These challenges in online stream of data are known as
concept drift. In this paper, we proposed the Adaptive Convolutional ELM method
(ACNNELM) as enhancement of Convolutional Neural Network (CNN) with a hybrid
Extreme Learning Machine (ELM) model plus adaptive capability. This method is
aimed for concept drift handling. We enhanced the CNN as convolutional
hiererchical features representation learner combined with Elastic ELM
(E$^2$LM) as a parallel supervised classifier. We propose an Adaptive OS-ELM
(AOS-ELM) for concept drift adaptability in classifier level (named ACNNELM-1)
and matrices concatenation ensembles for concept drift adaptability in ensemble
level (named ACNNELM-2). Our proposed Adaptive CNNELM is flexible that works
well in classifier level and ensemble level while most current methods only
proposed to work on either one of the levels.
  We verified our method in extended MNIST data set and not MNIST data set. We
set the experiment to simulate virtual drift, real drift, and hybrid drift
event and we demonstrated how our CNNELM adaptability works. Our proposed
method works well and gives better accuracy, computation scalability, and
concept drifts adaptability compared to the regular ELM and CNN. Further
researches are still required to study the optimum parameters and to use more
varied image data set.


title: Wave equation for 2D Landau Hamiltonian

abstract:
  This note is devoted to the study of the well-posedness of the Cauchy problem
for the Landau Hamiltonian wave equation in the plane, with nonzero constant
magnetic field. We show the well-posedness in suitably defined Sobolev spaces
taking into account the spectral properties of the operator.


title:
First measurement of unpolarized SIDIS cross section and cross section
  ratios from a $^3$He target

abstract:
  The unpolarized semi-inclusive deep-inelastic scattering (SIDIS) differential
cross sections in $^3$He($e,e^{\prime}\pi^{\pm}$)$X$ have been measured for the
first time in Jefferson Lab experiment E06-010 performed with a $5.9\,$GeV
$e^-$ beam on a $^3$He target. The experiment focuses on the valence quark
region, covering a kinematic range $0.12 < x_{bj} < 0.45$, $1 < Q^2 < 4 \,
\textrm{(GeV/c)}^2$, $0.45 < z_{h} < 0.65$, and $0.05 < P_t < 0.55 \,
\textrm{GeV/c}$. The extracted SIDIS differential cross sections of $\pi^{\pm}$
production are compared with existing phenomenological models while the $^3$He
nucleus approximated as two protons and one neutron in a plane wave picture, in
multi-dimensional bins. Within the experimental uncertainties, the azimuthal
modulations of the cross sections are found to be consistent with zero.


title:
Panning for Gold: Model-X Knockoffs for High-dimensional Controlled
  Variable Selection

abstract:
  Many contemporary large-scale applications involve building interpretable
models linking a large set of potential covariates to a response in a nonlinear
fashion, such as when the response is binary. Although this modeling problem
has been extensively studied, it remains unclear how to effectively control the
fraction of false discoveries even in high-dimensional logistic regression, not
to mention general high-dimensional nonlinear models. To address such a
practical problem, we propose a new framework of $model$-$X$ knockoffs, which
reads from a different perspective the knockoff procedure (Barber and Cand\`es,
2015) originally designed for controlling the false discovery rate in linear
models. Whereas the knockoffs procedure is constrained to homoscedastic linear
models with $n\ge p$, the key innovation here is that model-X knockoffs provide
valid inference from finite samples in settings in which the conditional
distribution of the response is arbitrary and completely unknown. Furthermore,
this holds no matter the number of covariates. Correct inference in such a
broad setting is achieved by constructing knockoff variables probabilistically
instead of geometrically. To do this, our approach requires the covariates be
random (independent and identically distributed rows) with a distribution that
is known, although we provide preliminary experimental evidence that our
procedure is robust to unknown/estimated distributions. To our knowledge, no
other procedure solves the $controlled$ variable selection problem in such
generality, but in the restricted settings where competitors exist, we
demonstrate the superior power of knockoffs through simulations. Finally, we
apply our procedure to data from a case-control study of Crohn's disease in the
United Kingdom, making twice as many discoveries as the original analysis of
the same data.


title:
Lightface mice with finitely many Woodin cardinals from optimal
  determinacy hypotheses

abstract:
  The determinacy of lightface $\Delta^1_{2n+2}$ and boldface
$\boldsymbol{\Pi}^1_{2n+1}$ sets implies the existence of an $(\omega,
\omega_1)$-iterable $M_{2n+1}^{\#}$.


title: Phonon Optimized Potentials

abstract:
  Molecular dynamics (MD) simulations have been extensively used to study
phonons and gain insight, but direct comparisons to experimental data are often
difficult, due to a lack of empirical interatomic potentials (EIPs) for
different systems. As a result, this issue has become a major barrier to
realizing the promise associated with advanced atomistic level modeling
techniques. Here, we present a general method for specifically optimizing EIPs
from ab initio inputs for the study of phonon transport properties, thereby
resulting in phonon optimized potentials (POPs). The method uses a genetic
algorithm (GA) to directly fit to the key properties that determine whether or
not the atomic level dynamics and most notably the phonon transport are
described properly.


title: Matrix elements from moments of correlation functions

abstract:
  Momentum-space derivatives of matrix elements can be related to their
coordinate-space moments through the Fourier transform. We derive these
expressions as a function of momentum transfer $Q^2$ for asymptotic in/out
states consisting of a single hadron. We calculate corrections to the finite
volume moments by studying the spatial dependence of the lattice correlation
functions. This method permits the computation of not only the values of matrix
elements at momenta accessible on the lattice, but also the momentum-space
derivatives, providing {\it a priori} information about the $Q^2$ dependence of
form factors. As a specific application we use the method, at a single lattice
spacing and with unphysically heavy quarks, to directly obtain the slope of the
isovector form factor at various $Q^2$, whence the isovector charge radius. The
method has potential application in the calculation of any hadronic matrix
element with momentum transfer, including those relevant to hadronic weak
decays.


title: Air modes of the Bacon internal resonator banjo

abstract:
  Sound measurements on a sequence of related, similar constructions with
slightly different dimensions confirm a simple picture of the air modes of the
internal resonator banjo's body. For the purpose of this study, the air modes
are decoupled from the soundboard (i.e., [drum] head) modes by replacing the
head with 3/4" plywood. The resulting characteristic features survive the
strong coupling of the air modes to the head and are in accord with the
qualitative distinctions recognized by banjo players.


title:
Sensitivity, quantum limits, and quantum enhancement of noise
  spectroscopies

abstract:
  We study the fundamental limits of noise spectroscopy using estimation
theory, Faraday rotation probing of an atomic spin system, and squeezed light.
We find a simple and general expression for the Fisher information, which
quantifies the sensitivity to spectral parameters such as resonance frequency
and linewidth. For optically-detected spin noise spectroscopy, we find that
shot noise imposes "local" standard quantum limits for any given probe power
and atom number, and also "global" standard quantum limits when probe power and
atom number are taken as free parameters. We confirm these estimation theory
results using non-destructive Faraday rotation probing of hot Rb vapor,
observing the predicted optima and finding good quantitative agreement with a
first-principles calculation of the spin noise spectra. Finally, we show
sensitivity beyond the atom- and photon-number-optimized global standard
quantum limit using squeezed light.


title: Xception: Deep Learning with Depthwise Separable Convolutions

abstract:
  We present an interpretation of Inception modules in convolutional neural
networks as being an intermediate step in-between regular convolution and the
depthwise separable convolution operation (a depthwise convolution followed by
a pointwise convolution). In this light, a depthwise separable convolution can
be understood as an Inception module with a maximally large number of towers.
This observation leads us to propose a novel deep convolutional neural network
architecture inspired by Inception, where Inception modules have been replaced
with depthwise separable convolutions. We show that this architecture, dubbed
Xception, slightly outperforms Inception V3 on the ImageNet dataset (which
Inception V3 was designed for), and significantly outperforms Inception V3 on a
larger image classification dataset comprising 350 million images and 17,000
classes. Since the Xception architecture has the same number of parameters as
Inception V3, the performance gains are not due to increased capacity but
rather to a more efficient use of model parameters.


title: Welcome or Not-Welcome: Reactions to Refugee Situation on Social Media

abstract:
  For many European countries, in 2015 the refugee situation developed from a
remote tragedy reported upon in the news to a situation they have to deal with
in their own neighborhood. Driven by this observation, we investigated the
development of the perception of the refugee situation during 2015 in Twitter.
Starting from a dataset of 1.7 Million tweets covering refugee-related topics
from May to December 2015, we investigated how the discussion on refugees
changed over time, in different countries as well as in relationship with the
evolution of the actual situation. In this paper we report and discuss our
findings from checking a set of hypotheses, such as that the closeness to the
actual situation would influence the intensity and polarity of discussions and
that news media takes a mediating role between the actual and perceived refugee
situation.


title:
DFT Simulations of Inter-Graphene-Layer Coupling with Rotationally
  Misaligned hBN Tunnel Barriers in Graphene/hBN/Graphene Tunnel FETs

abstract:
  Van der Waal's heterostrucutures allow for novel devices such as
two-dimensional-to-two-dimensional tunnel devices, exemplified by interlayer
tunnel FETs. These devices employ channel/tunnel-barrier/channel geometries.
However, during layer-by-layer exfoliation of these multi-layer materials,
rotational misalignment is the norm and may substantially affect device
characteristics. In this work, by using density functional theory methods, we
consider a reduction in tunneling due to weakened coupling across the
rotationally misaligned interface between the channel layers and the tunnel
barrier. As a prototypical system, we simulate the effects of rotational
misalignment of the tunnel barrier layer between aligned channel layers in a
graphene/hBN/graphene system. We find that rotational misalignment between the
channel layers and the tunnel barrier in this van der Waal's heterostructure
can significantly reduce coupling between the channels by reducing,
specifically, coupling across the interface between the channels and the tunnel
barrier. This weakened coupling in graphene/hBN/graphene with hBN misalignment
may be relevant to all such van der Waal's heterostructures.


title:
The Atacama Cosmology Telescope: Two-Season ACTPol Spectra and
  Parameters

abstract:
  We present the temperature and polarization angular power spectra measured by
the Atacama Cosmology Telescope Polarimeter (ACTPol). We analyze night-time
data collected during 2013-14 using two detector arrays at 149 GHz, from 548
deg$^2$ of sky on the celestial equator. We use these spectra, and the spectra
measured with the MBAC camera on ACT from 2008-10, in combination with Planck
and WMAP data to estimate cosmological parameters from the temperature,
polarization, and temperature-polarization cross-correlations. We find the new
ACTPol data to be consistent with the LCDM model. The ACTPol
temperature-polarization cross-spectrum now provides stronger constraints on
multiple parameters than the ACTPol temperature spectrum, including the baryon
density, the acoustic peak angular scale, and the derived Hubble constant.
Adding the new data to planck temperature data tightens the limits on damping
tail parameters, for example reducing the joint uncertainty on the number of
neutrino species and the primordial helium fraction by 20%.


title: Energy-efficient Delivery by Heterogeneous Mobile Agents

abstract:
  We consider the problem of delivering $m$ messages between specified
source-target pairs in a weighted undirected graph, by $k$ mobile agents
initially located at distinct nodes of the graph. Each agent consumes energy
proportional to the distance it travels in the graph and we are interested in
optimizing the total energy consumption for the team of agents. Unlike previous
related work, we consider heterogeneous agents with different rates of energy
consumption (weights~$w_i$). To solve the delivery problem, agents face three
major challenges: \emph{Collaboration} (how to work together on each message),
\emph{Planning} (which route to take) and \emph{Coordination} (how to assign
agents to messages).
  We first show that the delivery problem can be 2-approximated \emph{without}
collaborating and that this is best possible, i.e., we show that the
\emph{benefit of collaboration} is 2 in general. We also show that the benefit
of collaboration for a single message is~$1/\ln 2 \approx 1.44$. Planning turns
out to be \NP-hard to approximate even for a single agent, but can be
2-approximated in polynomial time if agents have unit capacities and do not
collaborate. We further show that coordination is \NP-hard even for agents with
unit capacity, but can be efficiently solved exactly if they have uniform
weights. Finally, we give a polynomial-time
$(4\max\tfrac{w_i}{w_j})$-approximation for message delivery with unit
capacities.


title: The equivariant Chern character as super holonomy on loop stacks

abstract:
  We study super parallel transport around super loops in a quotient stack, and
show that this geometry constructs a global version of the equivariant Chern
character.


title: Bosonic Partition Functions at Nonzero (Imaginary) Chemical Potential

abstract:
  We consider bosonic random matrix partition functions at nonzero chemical
potential and compare the chiral condensate, the baryon number density and the
baryon number susceptibility to the result of the corresponding fermionic
partition function. We find that as long as results are finite, the phase
transition of the fermionic theory persists in the bosonic theory. However, in
case that bosonic partition function diverges and has to be regularized, the
phase transition of the fermionic theory does not occur in the bosonic theory,
and the bosonic theory is always in the broken phase.


title: A Coordination Language for Databases

abstract:
  We present a coordination language for the modeling of distributed database
applications. The language, baptized Klaim-DB, borrows the concepts of
localities and nets of the coordination language Klaim but re-incarnates the
tuple spaces of Klaim as databases. It provides high-level abstractions and
primitives for the access and manipulation of structured data, with integrity
and atomicity considerations. We present the formal semantics of Klaim-DB and
develop a type system that avoids potential runtime errors such as certain
evaluation errors and mismatches of data format in tables, which are monitored
in the semantics. The use of the language is illustrated in a scenario where
the sales from different branches of a chain of department stores are
aggregated from their local databases. Raising the abstraction level and
encapsulating integrity checks in the language primitives have benefited the
modeling task considerably.


title: Deep Learning with Coherent Nanophotonic Circuits

abstract:
  Artificial Neural Networks are computational network models inspired by
signal processing in the brain. These models have dramatically improved the
performance of many learning tasks, including speech and object recognition.
However, today's computing hardware is inefficient at implementing neural
networks, in large part because much of it was designed for von Neumann
computing schemes. Significant effort has been made to develop electronic
architectures tuned to implement artificial neural networks that improve upon
both computational speed and energy efficiency. Here, we propose a new
architecture for a fully-optical neural network that, using unique advantages
of optics, promises a computational speed enhancement of at least two orders of
magnitude over the state-of-the-art and three orders of magnitude in power
efficiency for conventional learning tasks. We experimentally demonstrate
essential parts of our architecture using a programmable nanophotonic
processor.


title:
The Mass Dependence of Star Formation Histories in Barred Spiral
  Galaxies

abstract:
  We performed a series of 29 gasdynamical simulations of disc galaxies, barred
and unbarred, with various stellar masses, to study the impact of the bar on
star formation history. Unbarred galaxies evolve very smoothly, with a star
formation rate (SFR) that varies by at most a factor of three over a period of
2 Gyr. The evolution of barred galaxies is much more irregular, especially at
high stellar masses. In these galaxies, the bar drives a substantial amount of
gas toward the centre, resulting in a high SFR, and producing a starburst in
the most massive galaxies. Most of the gas is converted into stars, and gas
exhaustion leads to a rapid drop of star formation after the starburst. In
massive barred galaxies (stellar mass M* > 2x10^10 Msun) the large amount of
gas funnelled toward the centre is completely consumed by the starburst, while
in lower-mass barred galaxies it is only partially consumed. Gas concentration
is thus higher in lower-mass barred galaxies than it is in higher-mass ones.
Even though unbarred galaxies funnelled less gas toward their centre, the lower
SFR allows this gas to accumulate. At late times, the star formation efficiency
is higher in barred galaxies than unbarred ones, enabling these galaxies to
maintain a higher SFR with a smaller gas supply. Several properties, such as
the global SFR, central SFR, or central gas concentration, vary monotonically
with time for unbarred galaxies, but not for barred galaxies. Therefore one
must be careful when comparing barred and unbarred galaxies that share one
observational property, since these galaxies might be at very different stages
of their respective evolution.


title: Matrix commuting differential operators of rank 2

abstract:
  In this paper we propose a very effective method for constructing matrix
commuting differential operators of rank 2 and vector rank (2,2). We find new
matrix commuting differential operators L, M of orders 2 and 2g respectively.


title: Equidistribution, Uniform distribution: a probabilist's perspective

abstract:
  The theory of equidistribution is about hundred years old, and has been
developed primarily by number theorists and theoretical computer scientists. A
motivated uninitiated peer could encounter difficulties perusing the
literature, due to various synonyms and polysemes used by different schools.
One purpose of this note is to provide a short introduction for probabilists.
We proceed by recalling a perspective originating in a work of the second
author from 2002. Using it, various new examples of completely uniformly
distributed (mod 1) sequences, in the "metric" (meaning almost sure stochastic)
sense, can be easily exhibited. In particular, we point out natural
generalizations of the original $p$-multiply equidistributed sequence $k^p\, t$
mod 1, $k\geq 1$ (where $p\in \mathbb{N}$ and $t\in[0,1]$), due to Hermann Weyl
in 1916. In passing, we also derive a Weyl-like criterion for weakly completely
equidistributed (also known as WCUD) sequences, of substantial recent interest
in MCMC simulations.
  The translation from number theory to probability language brings into focus
a version of the strong law of large numbers for weakly correlated
complex-valued random variables, the study of which was initiated by Weyl in
the aforementioned manuscript, followed up by Davenport, Erd\"{o}s and LeVeque
in 1963, and greatly extended by Russell Lyons in 1988. In this context, an
application to $\infty$-distributed Koksma's numbers $t^k$ mod 1, $k\geq 1$
(where $t\in[1,a]$ for some $a>1$), and an important generalization by
Niederreiter and Tichy from 1985 are discussed.
  The paper contains negligible amount of new mathematics in the strict sense,
but its perspective and open questions included in the end could be of
considerable interest to probabilists and statisticians, as well as certain
computer scientists and number theorists.


title: Vertical stability of circular orbits in relativistic razor-thin disks

abstract:
  During the last few decades, there has been a growing interest in exact
solutions of Einstein equations describing razor-thin disks. Despite the
progress in the area, the analytical study of geodesic motion crossing the disk
plane in these systems is not yet so developed. In the present work, we propose
a definite vertical stability criterion for circular equatorial timelike
geodesics in static, axially symmetric thin disks, possibly surrounded by other
structures preserving axial symmetry. It turns out that the strong energy
condition for the disk stress-energy content is sufficient for vertical
stability of these orbits. Moreover, adiabatic invariance of the vertical
action variable gives us an approximate third integral of motion for oblique
orbits which deviate slightly from the equatorial plane. Such new approximate
third integral certainly points to a better understanding of the analytical
properties of these orbits. The results presented here, derived for static
spacetimes, may be a starting point to study the motion around rotating,
stationary razor-thin disks. Our results also allow us to conjecture that the
strong energy condition should be sufficient to assure transversal stability of
periodic orbits for any singular timelike hypersurface, provided it is
invariant under the geodesic flow.


title:
Adaptive Aggregation-based Domain Decomposition Multigrid for Twisted
  Mass Fermions

abstract:
  The Adaptive Aggregation-based Domain Decomposition Multigrid method
(arXiv:1303.1377) is extended for two degenerate flavors of twisted mass
fermions. By fine-tuning the parameters we achieve a speed-up of the order of
hundred times compared to the conjugate gradient algorithm for the physical
value of the pion mass. A thorough analysis of the aggregation parameters is
presented, which provides a novel insight into multigrid methods for lattice
QCD independently of the fermion discretization.


title: Sub-Shimura Varieties for type O(2,n)

abstract:
  We give a classification, up to consideration of component groups, of
sub-Shimura varieties of those Shimura Varieties attached to orthogonal groups
of signature (2,n) over Q.


title: Combining local and global smoothing in multivariate density estimation

abstract:
  Non-parametric estimation of a multivariate density estimation is tackled via
a method which combines traditional local smoothing with a form of global
smoothing but without imposing a rigid structure. Simulation work delivers
encouraging indications on the effectiveness of the method. An application to
density-based clustering illustrates a possible usage.


title: Distributed Averaging CNN-ELM for Big Data

abstract:
  Increasing the scalability of machine learning to handle big volume of data
is a challenging task. The scale up approach has some limitations. In this
paper, we proposed a scale out approach for CNN-ELM based on MapReduce on
classifier level. Map process is the CNN-ELM training for certain partition of
data. It involves many CNN-ELM models that can be trained asynchronously.
Reduce process is the averaging of all CNN-ELM weights as final training
result. This approach can save a lot of training time than single CNN-ELM
models trained alone. This approach also increased the scalability of machine
learning by combining scale out and scale up approaches. We verified our method
in extended MNIST data set and not-MNIST data set experiment. However, it has
some drawbacks by additional iteration learning parameters that need to be
carefully taken and training data distribution that need to be carefully
selected. Further researches to use more complex image data set are required.


title:
Unified Control and Data Flow Diagrams Applied to Software Engineering
  and other Systems

abstract:
  More often than not, there is a need to understand the structure of complex
computer code: what functions and in what order they are called, how
information travels around static, input, and output variables, what depends on
what. As a rule, executable code and data are scattered among multiple files
and even multiple modules. Information is transmitted among variables which
often change names. These tangled relations greatly complicate the development,
maintenance, and redevelopment of code, its analysis for complexity and its
robustness. As of now, there is no tool which is capable of presenting the
real-life, useful diagram of actual code. Conventional flowcharts fail.
Proposed is the method which overcomes these difficulties. The main idea is
that functionality of software can be described through flows of control, which
is essentially flows of time, and flows of data. These are inseparable. The
second idea is to follow very strict system boundaries and distinctions with
respect to modules, functions, blocks, and operators, as well as data holders,
showing them all as subsystems, in other words, by clearly expressing the
system structure when every piece of executable code and every variable may
have its own graphical representation. The third is defining timelines as the
entities clearly separated from the connected blocks of code. Timelines allow
presentation of nesting of the control flow as deep as necessary. As a proof of
concept, the same methods successfully describe production systems. Keywords:
flowchart, UML, software diagram, visual programming, extreme programming,
extreme modeling, control flow, data flow.


title:
Spin-orbit coupling controlled $J=3/2$ electronic ground state in
  5$d^{3}$ oxides

abstract:
  Entanglement of spin and orbital degrees of freedom drives the formation of
novel quantum and topological physical states. Discovering new spin-orbit
entangled ground states and emergent phases of matter requires both
experimentally probing the relevant energy scales and applying suitable
theoretical models. Here we report resonant inelastic x-ray scattering
measurements of the transition metal oxides Ca$_3$LiOsO$_6$ and Ba$_2$YOsO$_6$.
We invoke an intermediate coupling approach that incorporates both spin-orbit
coupling and electron-electron interactions on an even footing and reveal the
ground state of $5d^3$ based compounds, which has remained elusive in
previously applied models, is a novel spin-orbit entangled J=3/2 electronic
ground state. This work reveals the hidden diversity of spin-orbit controlled
ground states in 5d systems and introduces a new arena in the search for
spin-orbit controlled phases of matter.


title: Are there moonlets near the Uranian alpha and beta rings?

abstract:
  The Voyager 2 Radio Science Subsystem occultations of the Uranian alpha and
beta rings exhibit quasi-periodic optical depth variations with radial
wavelengths that vary with longitude. These patterns may be wakes from small
moonlets orbiting exterior to these rings. Based on the observed structures in
the rings, we estimate that the moonlets would need to be located about 100 km
exterior to the rings' semimajor axes and be 2-7 km in radius. Such moonlets
could help keep the rings confined. Due to their small radii and presumed low
albedo, the expected brightness of these moonlets is on the order of the noise
in Voyager 2 images.


title: Step Timing Adjustment: A Step toward Generating Robust Gaits

abstract:
  Step adjustment for humanoid robots has been shown to improve robustness in
gaits. However, step duration adaptation is often neglected in control
strategies. In this paper, we propose an approach that combines both step
location and timing adjustment for generating robust gaits. In this approach,
step location and step timing are decided, based on feedback from the current
state of the robot. The proposed approach is comprised of two stages. In the
first stage, the nominal step location and step duration for the next step or a
previewed number of steps are specified. In this stage which is done at the
start of each step, the main goal is to specify the best step length and step
duration for a desired walking speed. The second stage deals with finding the
best landing point and landing time of the swing foot at each control cycle. In
this stage, stability of the gaits is preserved by specifying a desired offset
between the swing foot landing point and the Divergent Component of Motion
(DCM) at the end of current step. After specifying the landing point of the
swing foot at a desired time, the swing foot trajectory is regenerated at each
control cycle to realize desired landing properties. Simulation on different
scenarios shows the robustness of the generated gaits from our proposed
approach compared to the case where no timing adjustment is employed.


title:
Frame completions with prescribed norms: local minimizers and
  applications

abstract:
  Let $\mathcal F_0=\{f_i\}_{i\in\mathbb{I}_{n_0}}$ be a finite sequence of
vectors in $\mathbb C^d$ and let $\mathbf{a}=(a_i)_{i\in\mathbb{I}_k}$ be a
finite sequence of positive numbers. We consider the completions of $\cal F_0$
of the form $\cal F=(\cal F_0,\cal G)$ obtained by appending a sequence $\cal
G=\{g_i\}_{i\in\mathbb{I}_k}$ of vectors in $\mathbb C^d$ such that
$\|g_i\|^2=a_i$ for $i\in\mathbb{I}_k$, and endow the set of completions with
the metric $d(\cal F,\tilde {\mathcal F}) =\max\{ \,\|g_i-\tilde g_i\|: \
i\in\mathbb{I}_k\}$ where $\tilde {\cal F}=(\cal F_0,\,\tilde {\cal G})$. In
this context we show that local minimizers on the set of completions of a
convex potential $\text{P}_\varphi$, induced by a strictly convex function
$\varphi$, are also global minimizers. In case that $\varphi(x)=x^2$ then
$\text{P}_\varphi$ is the so-called frame potential introduced by Benedetto and
Fickus, and our work generalizes several well known results for this potential.
We show that there is an intimate connection between frame completion problems
with prescribed norms and frame operator distance (FOD) problems. We use this
connection and our results to settle in the affirmative a generalized version
of Strawn's conjecture on the FOD.


title: Interpolating sequences on the bidisk

abstract:
  We give a characterization of interpolating sequences for bounded analytic
functions on the bidisk.


title:
BBGKY chain and kinetic equations for the level dynamics in an
  externally perturbed quantum system

abstract:
  Theoretical description and simulation of large quantum coherent systems out
of equilibrium remains a daunting task. Here we are developing a new approach
to it based on the Pechukas-Yukawa formalism, which is especially convenient in
case of an adiabatically slow external perturbation. In this formalism the
dynamics of energy levels in an externally perturbed quantum system as a
function of the perturbation parameter is mapped on that of a fictitious
one-dimensional classical gas of particles with cubic repulsion. Equilibrium
statistical mechanics of this Pechukas gas allows to reproduce the random
matrix theory of energy levels. In the present work, we develop the
nonequilibrium statistical mechanics of the Pechukas gas, starting with the
derivation of the Bogoliubov-Born-Green-Kirkwood-Yvon (BBGKY) chain of
equations for the appropriate generalized distribution functions. Sets of
approximate kinetic equations can be consistently obtained by breaking this
chain at a particular point (i.e. approximating all higher-order distribution
functions by the products of the lower-order ones). When complemented by the
equations for the level occupation numbers and inter-level transition
amplitudes, they allow to describe the nonequilibrium evolution of the quantum
state of the system, which can describe better a large quantum coherent system
than the currently used approaches. In particular, we find that corrections to
the factorized approximation of the distribution function scale as 1/N, where N
is the number of the "Pechukas gas particles" (i.e. energy levels in the
system).


title: Geometric random graphs and Rado sets in sequence spaces

abstract:
  We consider a random geometric graph model, where pairs of vertices are
points in a metric space and edges are formed independently with fixed
probability $p$ between pairs within threshold distance $\delta $. A countable
dense set in a metric space is {\sl Rado} if this random model gives, with
probability 1, a graph that is unique up to isomorphism. In earlier work, the
first two authors proved that in finite dimensional spaces $\mathbb{R}^n$
equipped with the $\ell_{\infty}$ norm, all countable dense set satisfying a
mild non-integrality condition are Rado. In this paper, we extend this result
to infinite-dimensional spaces. If the underlying metric space is a separable
Banach space, then we show in some cases that we can almost surely recover the
Banach space from such a geometric random graph. More precisely, we show that
in the sequence spaces $c$ and $c_0$, for measures $\mu$ satisfying certain
conditions, $\mu^\N$-almost all countable sets are Rado. Moreover, with
probability 1, in $c$ as in $c_0$, all graphs obtained from the random
geometric model with a randomly chosen dense countable vertex set are
isomorphic to each other. Finally, we show that representatives of the
isomorphism classes obtained in this way from $c$ and $c_0$ are non-isomorphic
to each other, and also non-isomorphic to their counterparts obtained from
finite dimensional spaces.


title: The three point Pick problem on the Bidisk

abstract: We analyze the three point Pick interpolation problem on the bidisk


title: A simple construction of positive loops of Legendrians

abstract:
  We construct positive loops of Legendrian submanifolds in several instances.
In particular, we partially recover G. Liu's result stating that any loose
Legendrian admits a positive loop, under some mild topological assumptions on
the Legendrian. Moreover, we show contractibility of the constructed loops
under an extra topological assumption.


title: Hydrodynamics of bilayer membranes with diffusing transmembrane proteins

abstract:
  We consider the hydrodynamics of lipid bilayers containing transmembrane
proteins of arbitrary shape. This biologically-motivated problem is relevant to
the cell membrane, whose fluctuating dynamics play a key role in phenomena
ranging from cell migration, intercellular transport, and cell communication.
Using Onsager's variational principle, we derive the equations that govern the
relaxation dynamics of the membrane shape, of the mass densities of the bilayer
leaflets, and of the diffusing proteins' concentration. With our generic
formalism, we obtain several results on membrane dynamics. We find that
proteins that span the bilayer increase the intermonolayer friction
coefficient. The renormalization, which can be significant, is in inverse
proportion to the protein's mobility. Second, we find that asymmetric proteins
couple to the membrane curvature and to the difference in monolayer densities.
For practically all accessible membrane tensions ($\sigma> 10^{-8}$ N/m) we
show that the protein density is the slowest relaxing variable. Furthermore,
its relaxation rate decreases at small wavelengths due to the coupling to
curvature. We apply our formalism to the large-scale diffusion of a
concentrated protein patch. We find that the diffusion profile is not
self-similar, owing to the wavevector dependence of the effective diffusion
coefficient.


title: Safe and Robust Robot Maneuvers Based on Reach Control

abstract:
  In this paper, we investigate the synthesis of piecewise affine feedback
controllers to address the problem of safe and robust controller design in
robotics based on high-level controls specifications. The methodology is based
on formulating the problem as a collection of reach control problems on a
polytopic state space. Reach control has so far only been developed in theory
and has not been tested experimentally on a real system before. Using a
quadrocopter as our experimental platform, we show that these theoretical tools
can achieve fast, albeit safe and robust maneuvers. In contrast to most
traditional control techniques, the reach control approach does not require a
predefined open-loop reference trajectory or spacial path. Experimental results
on a quadrocopter show the effectiveness and robustness of this control
approach. In a proof-of-concept demonstration, the reach controller is
implemented in one translational direction while the other degrees of freedom
are stabilized by separate controllers.


title: Charge metastability and hysteresis in the quantum Hall regime

abstract:
  We report simultaneous quasi-dc magnetotransport and high frequency surface
acoustic wave measurements on bilayer two-dimensional electron systems in GaAs.
Near strong integer quantized Hall states a strong magnetic field sweep
hysteresis in the velocity of the acoustic waves is observed at low
temperatures. This hysteresis indicates the presence of a metastable state with
anomalously high conductivity in the interior of the sample. This
non-equilibrium state is not revealed by conventional low frequency transport
measurements which are dominated by dissipationless transport at the edge of
the 2D system. We find that a field-cooling technique allows the equilibrium
charge configuration within the interior of the sample to be established. A
simple model for this behavior is discussed.


title: Final Service Provider DevOps concept and evaluation

abstract:
  This report presents the results of the UNIFY Service Provider DevOps
activities. First, we present the final definition and assessment of the
concept. SP-DevOps is realized by a combination of various functional
components facilitating integrated service verification, efficient and
programmable observability, and automated troubleshooting processes. Our
assessment shows that SP-DevOps can help providers to reach a medium level of
DevOps maturity and allows significant reduction in OPEX. Second, we focus on
the evaluation of the proposed SP-DevOps components. The set of tools proposed
supports ops and devs across all stages, with a focus on the deployment,
operation and debugging phases, and allows to activate automated processes for
operating NFV environments. Finally, we present use-cases and our demonstrators
for selected process implementions, which allowed the functional validation of
SP-DevOps.


title:
The role of body flexibility in stroke enhancements for finite-length
  undulatory swimmers in viscoelastic fluids

abstract:
  The role of passive body dynamics on the kinematics of swimming
micro-organisms in complex fluids is investigated. Asymptotic analysis of small
amplitude motions of a finite-length undulatory swimmer in a Stokes-Oldroyd-B
fluid is used to predict shape changes that result as body elasticity and fluid
elasticity are varied. Results from the analysis are compared with numerical
simulations, and the small amplitude analysis of shape changes is
quantitatively accurate at both small and large amplitudes, even for strongly
elastic flows. We compute a stroke-induced swimming speed that accounts for the
shape changes, but not additional effects of fluid elasticity. Elastic induced
shape changes lead to larger amplitude strokes for sufficiently soft swimmers
in a viscoelastic fluid, and these stroke boosts can lead to swimming
speed-ups, but we find that additional effects of fluid elasticity generically
slow down swimmers. High amplitude strokes in strongly elastic flows lead to a
qualitatively different regime in which highly concentrated elastic stresses
accumulate near swimmer bodies and where dramatic slow-downs are seen.


title:
Thouless energy and multifractality across the many-body localization
  transition

abstract:
  Thermal and many-body localized phases are separated by a dynamical phase
transition of a new kind. We analyze the distribution of off-diagonal matrix
elements of local operators across the many-body localization transition (MBLT)
in a disordered spin chain, and use it to characterize the breakdown of the
eigenstate thermalization hypothesis and to extract the many-body Thouless
energy. We find a wide critical region around the MBLT, where Thouless energy
becomes smaller than the level spacing, while matrix elements show critical
dependence on the energy difference. In the same region, matrix elements,
viewed as amplitudes of a fictitious wave function, exhibit strong
multifractality. Our findings show that the correlation length becomes larger
than the accessible system sizes in a broad range of disorder strength values,
and shed light on the critical behaviour of MBL systems.

categories: cond-mat.dis-nn cond-mat.mes-hall cond-mat.stat-mech cond-mat.str-el


title:
Shock Wave Interactions and the Riemann-flat Condition: The Geometry
  behind Metric Smoothing and the Existence of Locally Inertial Frames in
  General Relativity

abstract:
  We prove that the essential smoothness of the gravitational metric at shock
waves in GR, a PDE regularity issue for weak solutions of the Einstein
equations, is determined by a geometrical condition which we introduce and name
the {\it Riemann-flat condition}. The Riemann-flat condition determines whether
or not the essential smoothness of the gravitational metric is two full
derivatives more regular than the Riemann curvature tensor. This provides a
geometric framework for the open problem as to whether {\it regularity
singularities} (points where the curvature is in $L^\infty$ but the essential
smoothness of the gravitational metric is only Lipschitz continuous) can be
created by shock wave interaction in GR, or whether metrics Lipschitz at shocks
can always be smoothed one level to $C^{1,1}$ by coordinate transformation. As
a corollary of the ideas we give a proof that locally inertial frames always
exist in a natural sense for shock wave metrics in spherically symmetric
spacetimes, independent of whether the metric itself can be smoothed to
$C^{1,1}$ locally. This latter result yields an explicit procedure (analogous
to Riemann Normal Coordinates in smooth spacetimes) for constructing locally
inertial coordinates for Lipschitz metrics, and is a new regularity result for
GR solutions constructed by the Glimm scheme.


title:
Grad-CAM: Visual Explanations from Deep Networks via Gradient-based
  Localization

abstract:
  We propose a technique for producing "visual explanations" for decisions from
a large class of CNN-based models, making them more transparent. Our approach -
Gradient-weighted Class Activation Mapping (Grad-CAM), uses the gradients of
any target concept, flowing into the final convolutional layer to produce a
coarse localization map highlighting important regions in the image for
predicting the concept. Grad-CAM is applicable to a wide variety of CNN
model-families: (1) CNNs with fully-connected layers, (2) CNNs used for
structured outputs, (3) CNNs used in tasks with multimodal inputs or
reinforcement learning, without any architectural changes or re-training. We
combine Grad-CAM with fine-grained visualizations to create a high-resolution
class-discriminative visualization and apply it to off-the-shelf image
classification, captioning, and visual question answering (VQA) models,
including ResNet-based architectures. In the context of image classification
models, our visualizations (a) lend insights into their failure modes, (b) are
robust to adversarial images, (c) outperform previous methods on localization,
(d) are more faithful to the underlying model and (e) help achieve
generalization by identifying dataset bias. For captioning and VQA, we show
that even non-attention based models can localize inputs. We devise a way to
identify important neurons through Grad-CAM and combine it with neuron names to
provide textual explanations for model decisions. Finally, we design and
conduct human studies to measure if Grad-CAM helps users establish appropriate
trust in predictions from models and show that Grad-CAM helps untrained users
successfully discern a 'stronger' nodel from a 'weaker' one even when both make
identical predictions. Our code is available at
https://github.com/ramprs/grad-cam/, along with a demo at
http://gradcam.cloudcv.org, and a video at youtu.be/COjUB9Izk6E.


title:
An Automatic System for Acoustic Microphone Geometry Calibration based
  on Minimal Solvers

abstract:
  In this paper, robust detection, tracking and geometry estimation methods are
developed and combined into a system for estimating time-difference estimates,
microphone localization and sound source movement. No assumptions on the 3D
locations of the microphones and sound sources are made. The system is capable
of tracking continuously moving sound sources in an reverberant environment.
The multi-path components are explicitly tracked and used in the geometry
estimation parts. The system is based on matching between pairs of channels
using GCC-PHAT. Instead of taking a single maximum at each time instant from
each such pair, we select the four strongest local maxima. This produce a set
of hypothesis to work with in the subsequent steps, where consistency
constraints between the channels and time-continuity constraints are exploited.
In the paper it demonstrated how such detections can be used to estimate
microphone positions, sound source movement and room geometry. The methods are
tested and verified using real data from several reverberant environments. The
evaluation demonstrated accuracy in the order of few millimeters.


title:
New theory of diffusive and coherent nature of optical wave via a
  quantum walk

abstract:
  We propose a new theory on a relation between diffusive and coherent nature
in one dimensional wave mechanics based on a quantum walk. It is known that the
quantum walk in homogeneous matrices provides the coherent property of wave
mechanics. Using the recent result of a localization phenomenon in a
one-dimensional quantum walk (Konno, Quantum Inf. Proc. (2010) 9, 405-418), we
numerically show that the randomized localized matrices suppress the coherence
and give diffusive nature.


title:
Color-kinematics duality and Sudakov form factor at five loops for N=4
  supersymmetric Yang-Mills theory

abstract:
  Using color-kinematics duality, we construct for the first time the full
integrand of the five-loop Sudakov form factor in N=4 super-Yang-Mills theory,
including non-planar contributions. This result also provides a first
manifestation of the color-kinematics duality at five loops. The integrand is
explicitly ultraviolet finite when D<26/5, coincident with the known finiteness
bound for amplitudes. If the double-copy method could be applied to the form
factor, this would indicate an interesting ultraviolet finiteness bound for N=8
supergravity at five loops. The result is also expected to provide an essential
input for computing the five-loop non-planar cusp anomalous dimension.


title: Causal-order superposition as an enabler of free will

abstract:
  It is often argued that bottom-up causation under a physicalist, reductionist
worldview precludes free will in the libertarian sense. On the one hand, the
paradigm of classical mechanics makes determinism inescapable, while on the
other, the leading models that allow a role for quantum effects are
noncommittal regarding how conscious agents are supposed to translate
indeterminacy into self-formed choice. Recent developments, however, not only
imply that self-formed decisions are possible, but actually suggest how they
might come about. The cornerstone appears to be causality superposition rather
than quantum-state entanglement, as is usually assumed, and the natural arena
for applying these developments is (perhaps ironically) a framework that was
built without any consideration for quantum effects.


title: Readout technologies for directional WIMP Dark Matter detection

abstract:
  The measurement of the direction of WIMP-induced nuclear recoils is a
compelling but technologically challenging strategy to provide an unambiguous
signature of the detection of Galactic dark matter. Most directional detectors
aim to reconstruct the dark-matter-induced nuclear recoil tracks, either in gas
or solid targets. The main challenge with directional detection is the need for
high spatial resolution over large volumes, which puts strong requirements on
the readout technologies. In this paper we review the various detector readout
technologies used by directional detectors. In particular, we summarize the
challenges, advantages and drawbacks of each approach, and discuss future
prospects for these technologies.

categories: physics.ins-det astro-ph.CO astro-ph.IM hep-ex


title: Second Infintesimal Neighborhoods of Projective Bundle Sections

abstract:
  This short paper shows that a projective bundle over a smooth variety with a
section can be uniquely recovered from the embedding of the section in its
second infinitesimal neighborhood within the bundle.


title: Collider Signatures of Flavorful Higgs Bosons

abstract:
  Motivated by our limited knowledge of the Higgs couplings to first two
generation fermions, we analyze the collider phenomenology of a class of two
Higgs doublet models (2HDMs) with a non-standard Yukawa sector. One Higgs
doublet is mainly responsible for the masses of the weak gauge bosons and the
third generation fermions, while the second Higgs doublet provides mass for the
lighter fermion generations. The characteristic collider signatures of this
setup differ significantly from well-studied 2HDMs with natural flavor
conservation, flavor alignment, or minimal flavor violation. New production
mechanisms for the heavy scalar, pseudoscalar, and charged Higgs involving
second generation quarks can become dominant. The most interesting decay modes
include H/A -> cc, tc, {\mu}{\mu}, {\tau}{\mu} and H+ -> cb, cs, {\mu}{\nu}.
Searches for low mass di-muon resonances are currently among the best probes of
the heavy Higgs bosons in this setup.


title: Statistics of Dark Matter Substructure: III. Halo-to-Halo Variance

abstract:
  We present a study of unprecedented statistical power regarding the
halo-to-halo variance of dark matter substructure. Using a combination of
N-body simulations and a semi-analytical model, we investigate the variance in
subhalo mass fractions and subhalo occupation numbers, with an emphasis on how
these statistics scale with halo formation time. We demonstrate that the
subhalo mass fraction, f_sub, is mainly a function of halo formation time, with
earlier forming haloes having less substructure. At fixed formation redshift,
the average f_sub is virtually independent of halo mass, and the mass
dependence of f_sub is therefore mainly a manifestation of more massive haloes
assembling later. We compare observational constraints on f_sub from
gravitational lensing to our model predictions and simulation results. Although
the inferred f_sub are substantially higher than the median LCDM predictions,
they fall within the 95th percentile due to halo-to-halo variance. We show that
while the halo occupation distribution of subhaloes, P(N|M), is
super-Poissonian for large <N>, a well established result, it becomes
sub-Poissonian for <N> < 2. Ignoring the non-Poissonity results in systematic
errors of the clustering of galaxies of a few percent, and with a complicated
scale- and luminosity-dependence. Earlier-formed haloes have P(N|M) closer to a
Poisson distribution, suggesting that the dynamical evolution of subhaloes
drives the statistics towards Poissonian. Contrary to a recent claim, the
non-Poissonity of subhalo occupation statistics does not vanish by selecting
haloes with fixed mass and fixed formation redshift. Finally, we use subhalo
occupation statistics to put loose constraints on the mass and formation
redshift of the Milky Way halo. Using observational constraints on the V_max of
the most massive satellites, we infer that 0.25<M_vir/10^12M_sun/h<1.4 and
0.1<z_f<1.4 at 90% confidence.


title:
Robust sparse image reconstruction of radio interferometric observations
  with purify

abstract:
  Next-generation radio interferometers, such as the Square Kilometre Array
(SKA), will revolutionise our understanding of the universe through their
unprecedented sensitivity and resolution. However, to realise these goals
significant challenges in image and data processing need to be overcome. The
standard methods in radio interferometry for reconstructing images, such as
CLEAN, have served the community well over the last few decades and have
survived largely because they are pragmatic. However, they produce
reconstructed inter\-ferometric images that are limited in quality and
scalability for big data. In this work we apply and evaluate alternative
interferometric reconstruction methods that make use of state-of-the-art sparse
image reconstruction algorithms motivated by compressive sensing, which have
been implemented in the PURIFY software package. In particular, we implement
and apply the proximal alternating direction method of multipliers (P-ADMM)
algorithm presented in a recent article. First, we assess the impact of the
interpolation kernel used to perform gridding and degridding on sparse image
reconstruction. We find that the Kaiser-Bessel interpolation kernel performs as
well as prolate spheroidal wave functions, while providing a computational
saving and an analytic form. Second, we apply PURIFY to real interferometric
observations from the Very Large Array (VLA) and the Australia Telescope
Compact Array (ATCA) and find images recovered by PURIFY are higher quality
than those recovered by CLEAN. Third, we discuss how PURIFY reconstructions
exhibit additional advantages over those recovered by CLEAN. The latest version
of PURIFY, with developments presented in this work, is made publicly
available.


title: Radiative shocks create environments for dust formation in novae

abstract:
  Classical novae commonly show evidence of rapid dust formation within months
of the outburst. However, it is unclear how molecules and grains are able to
condense within the ejecta, given the potentially harsh environment created by
ionizing radiation from the white dwarf. Motivated by the evidence for powerful
radiative shocks within nova outflows, we propose that dust formation occurs
within the cool, dense shell behind these shocks. We incorporate a simple
molecular chemistry network and classical nucleation theory with a model for
the thermodynamic evolution of the post-shock gas, in order to demonstrate the
formation of both carbon and forsterite ($\rm Mg_2SiO_4$) grains. The high
densities due to radiative shock compression ($n \sim 10^{14}$ cm$^{-3}$)
result in CO saturation and rapid dust nucleation. Grains grow efficiently to
large sizes $\gtrsim 0.1\mu$m, in agreement with IR observations of
dust-producing novae, and with total dust masses sufficient to explain massive
extinction events such as V705 Cas. As in dense stellar winds, dust formation
is CO-regulated, with carbon-rich flows producing carbon-rich grains and
oxygen-rich flows primarily forming silicates. CO is destroyed by non-thermal
particles accelerated at the shock, allowing additional grain formation at late
times, but the efficiency of this process appears to be low. Given observations
showing that individual novae produce both carbonaceous and silicate grains, we
concur with previous works attributing this bimodality to chemical
heterogeneity of the ejecta. Nova outflows are diverse and inhomogeneous, and
the observed variety of dust formation events can be reconciled by different
abundances, the range of shock properties, and the observer viewing angle. The
latter may govern the magnitude of extinction, with the deepest extinction
events occurring for observers within the binary equatorial plane.


title:
The Search for Failed Supernovae with the Large Binocular Telescope:
  Constraints from 7 Years of Data

abstract:
  We report updated results for the first 7 years of our program to monitor 27
galaxies within 10 Mpc using the Large Binocular Telescope to search for failed
supernovae (SNe) -- core-collapses of massive stars that form black holes
without luminous supernovae. In the new data, we identify no new compelling
candidates and confirm the existing candidate. Given the 6 successful
core-collapse SNe in the sample and one likely failed SN, the implied fraction
of core-collapses that result in failed SNe is $f = 0.14^{+0.33}_{-0.10}$ at
90% confidence. If the current candidate is a failed SN, the fraction of failed
SN naturally explains the missing high-mass red supergiant SN progenitors and
the black hole mass function. If the current candidate is ultimately rejected,
the data implies a 90% confidence upper limit on the failed SN fraction of $f <
0.35$.


title: Warped K\"ahler potentials and fluxes

abstract:
  The four-dimensional effective theory for type IIB warped flux
compactifications proposed in [1] is completed by taking into account the
backreaction of the K\"ahler moduli on the three-form fluxes. The only required
modification consists in a flux-dependent contribution to the chiral fields
parametrising the K\"ahler moduli. The resulting supersymmetric effective
theory satisfies the no-scale condition and consistently combines previous
partial results present in the literature. Similar results hold for M-theory
warped compactifications on Calabi-Yau fourfolds, whose effective field theory
and K\"ahler potential are also discussed.


title: Ultraviolet Halos Around Spiral Galaxies. I. Morphology

abstract:
  We examine ultraviolet halos around a sample of highly inclined galaxies
within 25 Mpc to measure their morphology and luminosity. Despite contamination
from galactic light scattered into the wings of the point-spread function, we
find that UV halos occur around each galaxy in our sample. Around most galaxies
the halos form a thick, diffuse disk-like structure, but starburst galaxies
with galactic superwinds have qualitatively different halos that are more
extensive and have filamentary structure. The spatial coincidence of the UV
halos above star-forming regions, the lack of consistent association with
outflows or extraplanar ionized gas, and the strong correlation between the
halo and galaxy UV luminosity suggest that the UV light is an extragalactic
reflection nebula. UV halos may thus represent 1-10 million solar masses of
dust within 2-10 kpc of the disk, whose properties may change with height in
starburst galaxies.


title: Advanced LIGO Constraints on Neutron Star Mergers and R-Process Sites

abstract:
  The role of compact binary mergers as the main production site of r-process
elements is investigated by combining stellar abundances of Eu observed in the
Milky Way, galactic chemical evolution (GCE) simulations, binary population
synthesis models, and Advanced LIGO gravitational wave measurements. We
compiled and reviewed seven recent GCE studies to extract the frequency of
neutron star - neutron star (NS-NS) mergers that is needed in order to
reproduce the observed [Eu/Fe] vs [Fe/H] relationship. We used our simple
chemical evolution code to explore the impact of different analytical
delay-time distribution (DTD) functions for NS-NS mergers. We then combined our
metallicity-dependent population synthesis models with our chemical evolution
code to bring their predictions, for both NS-NS mergers and black hole -
neutron star mergers, into a GCE context. Finally, we convolved our results
with the cosmic star formation history to provide a direct comparison with
current and upcoming Advanced LIGO measurements. When assuming that NS-NS
mergers are the exclusive r-process sites, and that the ejected r-process mass
per merger event is 0.01 Msun, the number of NS-NS mergers needed in GCE
studies is about 10 times larger than what is predicted by standard population
synthesis models. These two distinct fields can only be consistent with each
other when assuming optimistic rates, massive NS-NS merger ejecta, and low Fe
yields for massive stars. Population synthesis models and GCE simulations are
in agreement with the current upper limit (O1) established by Advanced LIGO
during their first run of observations. Upcoming measurements will provide
important constraints on the actual local NS-NS merger rate, will provide
insights on the plausibility of the GCE requirement, and will help to define
whether or not compact binary mergers can be the dominant source of r-process
elements in the Universe.


title:
Anisotropic transport of normal metal-barrier-normal metal junctions in
  monolayer phosphorene

abstract:
  We study transport properties of a phosphorene monolayer in the presence of
single and multiple potential barriers of height $U_0$ and width $d$, using
both continuum and microscopic lattice models, and show that the nature of
electron transport along its armchair edge ($x$ direction) is qualitatively
different from its counterpart in both conventional two-dimensional electron
gas with Schr\"odinger-like quasiparticles and graphene or surfaces of
topological insulators hosting massless Dirac quasiparticles. We show that the
transport, mediated by massive Dirac electrons, allows one to achieve
collimated quasiparticle motion along $x$ and thus makes monolayer phosphorene
an ideal experimental platform for studying Klein paradox. We study the
dependence of the tunneling conductance $G \equiv G_{xx}$ as a function of $d$
and $U_0$, and demonstrate that for a given applied voltage $V$ its behavior
changes from oscillatory to decaying function of $d$ for a range of $U_0$ with
finite non-zero upper and lower bounds, and provide analytical expression for
these bounds within which $G$ decays with $d$. We contrast such behavior of $G$
with that of massless Dirac electrons in graphene and also with that along the
zigzag edge ($y$ direction) in phosphorene where the quasiparticles obey an
effective Schr\"odinger equation at low energy. We also study transport through
multiple barriers along $x$ and demonstrate that these properties hold for
transport through multiple barrier as well. Finally, we suggest concrete
experiments which may verify our theoretical predictions.