title:
Modelling Dust Evolution in Galaxies with a Multiphase, Inhomogeneous
  ISM

abstract:
  We develop a model of dust evolution in a multiphase, inhomogeneous ISM
including dust growth and destruction processes. The physical conditions for
grain evolution are taken from hydrodynamical simulations of giant molecular
clouds in a Milky Way-like spiral galaxy. We improve the treatment of dust
growth by accretion in the ISM to investigate the role of the
temperature-dependent sticking coefficient and ion-grain interactions. From
detailed observational data on the gas-phase Si abundances [Si/H]_{gas}
measured in the local Galaxy, we derive a relation between the average
[Si/H]_{gas} and the local gas density n(H) which we use as a critical
constraint for the models. This relation requires a sticking coefficient that
decreases with the gas temperature. The synthetic relation constructed from the
spatial dust distribution reproduces the slope of -0.5 of the observed relation
in cold clouds. This slope is steeper than that for the warm medium and is
explained by the dust growth. We find that it occurs for all adopted values of
the minimum grain size a_{min} from 1 to 5nm. For the classical cut-off of
a_{min}=5 nm, the ion-grain interactions result in longer growth timescales and
higher [Si/H]_{gas} than the observed values. For a_{min} below 3 nm, the
ion-grain interactions enhance the growth rates, steepen the slope of
[Si/H]_{gas}-n(H) relation and provide a better match to observations. The
rates of dust re-formation in the ISM by far exceed the rates of dust
production by stellar sources as expected from simple evolution models. After
the cycle of matter in and out of dust reaches a steady state, the dust growth
balances the destruction operating on similar timescales of 350 Myr.


title:
Universal Fragment Descriptors for Predicting Electronic Properties of
  Inorganic Crystals

abstract:
  Historically, materials discovery has been driven by a laborious
trial-and-error process. The growth of materials databases and emerging
informatics approaches finally offer the opportunity to transform this practice
into data- and knowledge-driven rational design. By using data from the AFLOW
repository for high-throughput ab-initio calculations, we have generated
Quantitative Materials Structure-Property Relationship (QMSPR) models to
predict eight critical electronic and thermomechanical materials properties,
such as the metal/insulator classification, band gap energy, bulk and shear
moduli, Debye temperature, and heat capacity. The prediction accuracy obtained
with these QMSPR models approaches training data for virtually any
stoichiometric inorganic crystalline material. The success and universality of
these models is attributed to the construction of new materials
descriptors---referred to as the universal Property-Labeled Materials Fragments
(PLMF). The representation requires only minimal structural input and affords
straightforward model interpretation in terms of simple heuristic design rules
that guide rational materials design. This study demonstrates the power of
materials informatics to dramatically accelerate the search for new materials.


title: Application of multiview techniques to NHANES dataset

abstract:
  Disease prediction or classification using health datasets involve using
well-known predictors associated with the disease as features for the models.
This study considers multiple data components of an individual's health, using
the relationship between variables to generate features that may improve the
performance of disease classification models. In order to capture information
from different aspects of the data, this project uses a multiview learning
approach, using Canonical Correlation Analysis (CCA), a technique that finds
projections with maximum correlations between two data views. Data categories
collected from the NHANES survey (1999-2014) are used as views to learn the
multiview representations. The usefulness of the representations is
demonstrated by applying them as features in a Diabetes classification task.


title:
Revealing the source of the radial flow patterns in proton--proton
  collisions using hard probes

abstract:
  In this work, we propose a tool to reveal the origin of the collective-like
phenomena observed in proton--proton collisions. We exploit the fundamental
difference between the underlying mechanisms, color reconnection (CR) and
hydrodynamics, which produce radial flow patterns in \textsc{Pythia}~8 and
\textsc{Epos}~3, respectively. Specifically, we proceed by examining the
strength of the coupling between the soft and hard components which, by
construction, is larger in \textsc{Pythia}~8 than in \textsc{Epos}~3. We study
the transverse momentum ($p_{\rm T}$) distributions of charged pions, kaons and
(anti)protons in inelastic pp collisions at $\sqrt{s}=$ 7\,TeV produced at
mid-rapidity. Specific selections are made on an event-by-event basis as a
function of the charged particle multiplicity and the transverse momentum of
the leading jet ($p_{\rm T}^{\rm jet}$) reconstructed using the
\textsc{FastJet} algorithm at mid-pseudorapidity ($|\eta|<1$). From our
studies, quantitative and qualitative differences between \textsc{Pythia}~8 and
\textsc{Epos}~3 are found in the $p_{\rm T}$ spectra when (for a given
multiplicity class) the leading jet $p_{\rm T}$ is increased. In addition, we
show that for low-multiplicity events the presence of jets can produce radial
flow-like behavior. Motivated by our findings, we propose to perform a similar
analysis using experimental data from RHIC and LHC.


title: Resonance $X(5568)$ as an exotic axial-vector state

abstract:
  The mass and meson-current coupling constant of the resonance $X(5568)$, as
well as the width of the decay $X(5568)\to B_s^{\ast}\pi$ are calculated by
modeling the exotic $X(5568)$ resonance as a diquark-antidiquark state $%
X_b=[su][bd]$ with quantum numbers $J^{P}=1^{+}$. The calculations are made
employing QCD two-point sum rule method, where the quark, gluon and mixed
vacuum condensates up to dimension eight are taken into account. The sum rule
approach on the light-cone in its soft-meson approximation is used to explore
the vertex $X_bB_{s}^{\ast}\pi$ and extract the strong coupling $%
g_{X_bB_{s}^{\ast}\pi}$, which is a necessary ingredient to find the width of
the $X_b \to B_s^{\ast}\pi^{+}$ decay process. The obtained predictions are
compared with the experimental data of the D0 Collaboration, and results of
other theoretical works.


title: Rank Two Fourier-Mukai Transforms for K3 Surfaces

abstract:
  We study rank two locally-free Fourier-Mukai transforms on K3 surfaces and
show that they come in two distinct types according to whether the determinant
of a suitable twist of the kernel is positive or not. We show that a necessary
and sufficient condition on the existence of Fourier-Mukai transforms of rank 2
between the derived categories of K3 surfaces X and Y with negative twisted
determinant is that Y is isomorphic to X and there must exist a line bundle
with no cohomology. We use these results to prove that all reflexive K3
surfaces (including the degenerate ones) admit Fourier-Mukai transforms.


title: Ex Vacuo Atom Chip Bose-Einstein Condensate (BEC)

abstract:
  Ex vacuo atom chips, used in conjunction with a custom thin walled vacuum
chamber, have enabled the rapid replacement of atom chips for magnetically
trapped cold atom experiments. Atoms were trapped in $>2$ kHz magnetic traps
created using high power atom chips. The thin walled vacuum chamber allowed the
atoms to be trapped $\lesssim1$ mm from the atom chip conductors which were
located outside of the vacuum system. Placing the atom chip outside of the
vacuum simplified the electrical connections and improved thermal management.
Using a multi-lead Z-wire chip design, a Bose-Einstein condensate was produced
with an external atom chip. Vacuum and optical conditions were maintained while
replacing the Z-wire chip with a newly designed cross-wire chip. The atom chips
were exchanged and an initial magnetic trap was achieved in less than three
hours.


title: High anisotropy of fully hydrogenated borophene

abstract:
  We have studied the mechanical properties and phonon dispersions of fully
hydrogenated borophene (borophane) under strains by first principles
calculations. Uniaxial tensile strains along the a- and b-direction,
respectively, and biaxial tensile strain have been considered. Our results show
that the mechanical properties and phonon stability of borophane are both
highly anisotropic. The ultimate tensile strain along the a-direction is only
0.12, but it can be as large as 0.30 along the b-direction. Compared to
borophene and other 2D materials (graphene, graphane, silicene, silicane, h-BN,
phosphorene and MoS2), borophane presents the most remarkable anisotropy in
in-plane ultimate strain, which is very important for strain engineering.
Furthermore, the phonon dispersions under the three applied strains indicate
that borophane can withstand up to 5% and 15% uniaxial tensile strain along the
a- and b-direction, respectively, and 9% biaxial tensile strain, indicating
that mechanical failure in borophane is likely to originate from phonon
instability.


title:
Modelling Student Behavior using Granular Large Scale Action Data from a
  MOOC

abstract:
  Digital learning environments generate a precise record of the actions
learners take as they interact with learning materials and complete exercises
towards comprehension. With this high quantity of sequential data comes the
potential to apply time series models to learn about underlying behavioral
patterns and trends that characterize successful learning based on the granular
record of student actions. There exist several methods for looking at
longitudinal, sequential data like those recorded from learning environments.
In the field of language modelling, traditional n-gram techniques and modern
recurrent neural network (RNN) approaches have been applied to algorithmically
find structure in language and predict the next word given the previous words
in the sentence or paragraph as input. In this paper, we draw an analogy to
this work by treating student sequences of resource views and interactions in a
MOOC as the inputs and predicting students' next interaction as outputs. In
this study, we train only on students who received a certificate of completion.
In doing so, the model could potentially be used for recommendation of
sequences eventually leading to success, as opposed to perpetuating
unproductive behavior. Given that the MOOC used in our study had over 3,500
unique resources, predicting the exact resource that a student will interact
with next might appear to be a difficult classification problem. We find that
simply following the syllabus (built-in structure of the course) gives on
average 23% accuracy in making this prediction, followed by the n-gram method
with 70.4%, and RNN based methods with 72.2%. This research lays the ground
work for recommendation in a MOOC and other digital learning environments where
high volumes of sequential data exist.


title: Coherent observations of gravitational radiation with LISA and gLISA

abstract:
  The geosynchronous Laser Interferometer Space Antenna (gLISA) is a
space-based gravitational wave (GW) mission that, for the past five years, has
been under joint study at the Jet Propulsion Laboratory, Stanford University,
the National Institute for Space Research (I.N.P.E., Brazil), and Space Systems
Loral. If flown at the same time as the LISA mission, the two arrays will
deliver a joint sensitivity that accounts for the best performance of both
missions in their respective parts of the mHz band. This simultaneous operation
will result in an optimally combined sensitivity curve that is "white" from a
few mHz to 1 Hz, making the two antennas capable of detecting, with high
signal-to-noise ratios (SNRs), coalescing black-hole binaries (BHBs) with
masses in the range (10 - 100 million) solar masses. Their ability of jointly
tracking, with enhanced SNR, signals similar to that observed by the Advanced
Laser Interferometer Gravitational Wave Observatory (aLIGO) on September 14,
2015 (the GW150914 event) will result in a larger number of observable
small-mass binary black-holes and an improved precision of the parameters
characterizing these sources. Together, LISA, gLISA and aLIGO will cover, with
good sensitivity, a frequency band from a tenth of a mHz to a kHz frequency
band.


title: Self-Assembly of Shapes at Constant Scale using Repulsive Forces

abstract:
  The algorithmic self-assembly of shapes has been considered in several models
of self-assembly. For the problem of \emph{shape construction}, we consider an
extended version of the Two-Handed Tile Assembly Model (2HAM), which contains
positive (attractive) and negative (repulsive) interactions. As a result,
portions of an assembly can become unstable and detach. In this model, we
utilize fuel-efficient computation to perform Turing machine simulations for
the construction of the shape. In this paper, we show how an arbitrary shape
can be constructed using an asymptotically optimal number of distinct tile
types (based on the shape's Kolmogorov complexity). We achieve this at $O(1)$
scale factor in this straightforward model, whereas all previous results with
sublinear scale factors utilize powerful self-assembly models containing
features such as staging, tile deletion, chemical reaction networks, and tile
activation/deactivation. Furthermore, the computation and construction in our
result only creates constant-size garbage assemblies as a byproduct of
assembling the shape.


title:
The formation and migration of sand ripples in closed conduits:
  experiments with turbulent water flows

abstract:
  The transport of solid particles by a fluid flow is frequently found in
nature and industry. Some examples are the transport of sand in rivers and
hydrocarbon pipelines. When the shear stresses exerted by a fluid flow on a
granular bed remain moderate, some grains are set in motion without fluidizing
the bed; the moving grains form a layer, known as bed load, that moves while
maintaining contact with the fixed part of the bed. Under bed load conditions,
the granular bed may become unstable, generating ripples and dunes. Sand
ripples are commonly observed in closed conduits and pipes such as in petroleum
pipelines, sewer systems, and dredging lines. Although of importance for many
scientific domains and industrial applications, the formation of ripples in
closed conduits is not well understood, and the problem is still open. This
paper presents an experimental study on the formation and migration of sand
ripples under a turbulent closed-conduit flow and bed-load conditions. In our
experiments, fully-developed turbulent water flows were imposed over a granular
bed of known granulometry in a transparent channel, and bed load took place.
For different water flow rates and grain diameters, the growth and migration of
bedforms were filmed by a high-definition camera, and a numerical code was
developed to determine the wavelength and celerity of the bedforms from the
acquired images. The obtained results are compared with published stability
analyses.


title: Neutrinoless double beta decay from lattice QCD

abstract:
  While the discovery of non-zero neutrino masses is one of the most important
accomplishments by physicists in the past century, it is still unknown how and
in what form these masses arise. Lepton number-violating neutrinoless double
beta decay is a natural consequence of Majorana neutrinos and many BSM
theories, and many experimental efforts are involved in the search for these
processes. Understanding how neutrinoless double beta decay would manifest in
nuclear environments is key for understanding any observed signals. In these
proceedings we present an overview of a set of one- and two-body matrix
elements relevant for experimental searches for neutrinoless double beta decay,
describe the role of lattice QCD calculations, and present preliminary lattice
QCD results.


title: Laurent phenomenon algebras arising from surfaces

abstract:
  It was shown by Fomin, Shapiro and Thurston that some cluster algebras arise
from orientable surfaces. Subsequently, Dupont and Palesi extended this
construction to non-orientable surfaces. We link this framework to Lam and
Pylyavskyy's Laurent phenomenon algebras, showing that both orientable and
non-orientable unpunctured marked surfaces have an associated LP-algebra.


title: Interpolation and Commutant Lifting with Weights

abstract:
  Our two principle goals are generalizations of the commutant lifting theorem
and the Nevanlinna-Pick interpolation theorem to the context of Hardy algebras
built from $W^*$-correspondences endowed with a sequence of weights. These
theorems generalize theorems of Muhly and Solel from 1998 and 2004,
respectively, which were proved in settings without weights. Of special
interest is the fact that commutant lifting in our setting is a consequence of
Parrott's Lemma; it is inspired by work of Arias.


title: Predicting Band Gaps with Hybrid Density Functionals

abstract:
  We compare the ability of four popular hybrid density functionals (B3LYP,
B3PW91, HSE, and PBE0) for predicting band gaps of semiconductors and
insulators over a large benchmark set using a consistent methodology. We
observe no significant statistical dference in their overall performance
although the screened hybrid HSE is more accurate for typical semiconductors.
HSE can improve its accuracy for large large band gap materials --without
affecting that of semiconductors-- by including a larger portion of
Hartree-Fock exchange in its short range. Given that screened hybrids are
computationally much less expensive than their global counterparts, we conclude
that they are a better option for the black box prediction of band gaps.


title: Theta-stratifications, Theta-reductive stacks, and applications

abstract:
  These are expanded notes on a lecture of the same title at the 2015 AMS
summer institute in algebraic geometry. We give an introduction and overview of
the "beyond geometric invariant theory" program for analyzing moduli problems
in algebraic geometry. We discuss methods for analyzing stability in general
moduli problems, focusing on the moduli of coherent sheaves on a smooth
projective scheme as a toy example. We describe several applications: a general
structure theorem for the derived category of coherent sheaves on an algebraic
stack; some results on the topology of moduli stacks; and a "virtual
non-abelian localization formula" in K-theory. We also propose a generalization
of toric geometry to arbitrary compactifications of homogeneous spaces for
algebraic groups, and formulate a conjecture on the Hodge theory of
algebraic-symplectic stacks.


title: Full top quark mass dependence in Higgs boson pair production at NLO

abstract:
  We study the effects of the exact top-quark mass dependent two-loop
corrections to Higgs boson pair production by gluon fusion at the LHC and at a
100 TeV hadron collider. We perform a detailed comparison of the full
next-to-leading order result to various approximations at the level of
differential distributions and also analyse non-standard Higgs self-coupling
scenarios. We find that the different next-to-leading order approximations
differ from the full result by up to 50 percent in relevant differential
distributions. This clearly stresses the importance of the full NLO result.


title: Evidence for a nematic phase in La$_{1.75}$Sr$_{0.25}$NiO$_{4}$

abstract:
  Determining the nature of electronic states in doped Mott insulators remains
a challenging task. In the case of tetragonal La$_{2-x}$Sr$_{x}$NiO$_{4}$, the
occurrence of diagonal charge and spin stripe order in the ground state is now
well established. In contrast, the nature of the high-temperature "disordered"
state from which the stripe order develops has long been a subject of
controversy, with considerable speculation regarding a polaronic liquid.
Following on the recent detection of dynamic charge stripes, we use neutron
scattering measurements on an $x=0.25$ crystal to demonstrate that the
dispersion of the charge stripe excitations is anisotropic. This observation
provides compelling evidence for the presence of electronic nematic order.


title: The configuration space of a robotic arm in a tunnel

abstract:
  We study the motion of a robotic arm inside a rectangular tunnel. We prove
that the configuration space of all possible positions of the robot is a CAT(0)
cubical complex. This allows us to use techniques from geometric group theory
to find the optimal way of moving the arm from one position to another. We also
compute the diameter of the configuration space, that is, the longest distance
between two positions of the robot.


title:
Effect of aging-induced disorder on the quantum transport properties of
  atomically thin WTe$_{2}$

abstract:
  Atomically thin layers of transition-metal dicalcogenides (TMDCs) are often
known to be metastable in the ambient atmosphere. Understanding the mechanism
of degradation is essential for their future applications in nanoelectronics,
and thus has attracted intensive interest recently. Here, we demonstrate a
systematic study of atomically thin WTe$_{2}$ in its low temperature quantum
electronic transport properties. Strikingly, while the temperature dependence
of few layered WTe$_{2}$ showed clear metallic tendency in the fresh state,
degraded devices first exhibited a re-entrant insulating behavior, and finally
entered a fully insulating state. Correspondingly, a crossover from parabolic
to linear magnetoresistance, and finally to weak anti-localization was seen.
Real-time Raman scattering measurement, together with transmission electron
microscopy studies done before and after air degradation of atomically thin
WTe$_{2}$ further confirmed that the material gradually form amorphous islands.
It thus leads to localized electronic states and explains the low temperature
Coulomb gap observed in transport measurements. Our study reveals for the first
time the correlation between the unusual magnetotransport and disorder in
few-layered WTe$_{2}$, which is indispensable in providing guidance on its
future devices application.


title: Scalable Learning of Non-Decomposable Objectives

abstract:
  Modern retrieval systems are often driven by an underlying machine learning
model. The goal of such systems is to identify and possibly rank the few most
relevant items for a given query or context. Thus, such systems are typically
evaluated using a ranking-based performance metric such as the area under the
precision-recall curve, the $F_\beta$ score, precision at fixed recall, etc.
Obviously, it is desirable to train such systems to optimize the metric of
interest.
  In practice, due to the scalability limitations of existing approaches for
optimizing such objectives, large-scale retrieval systems are instead trained
to maximize classification accuracy, in the hope that performance as measured
via the true objective will also be favorable. In this work we present a
unified framework that, using straightforward building block bounds, allows for
highly scalable optimization of a wide range of ranking-based objectives. We
demonstrate the advantage of our approach on several real-life retrieval
problems that are significantly larger than those considered in the literature,
while achieving substantial improvement in performance over the
accuracy-objective baseline.


title: Center of Mass Momentum Dependent Interaction Between Ultracold Atoms

abstract:
  We show that a new type of two-body interaction, which depends on the
momentum of the center of mass (CoM) of these two particles, can be realized in
ultracold atom gases with a laser-modulaed magnetic Feshbach resonance (MFR).
Here the MFR is modulated by two laser beams propagating along different
directions, which can induce Raman transition between two-body bound states.
The Doppler effect causes the two-atom scattering length to be strongly
dependent on the CoM momentum of these two atoms. As a result, the effective
two-atom interaction is CoM-momentum dependent, while the one-atom free
Hamiltonian is still the simple kinetic energy ${\bf p}^2/(2m)$.


title: Quanta and Qualia

abstract:
  I sketch a line of thought about consciousness and physics that gives some
motivation for the hypothesis that conscious observers deviate - perhaps only
very subtly and slightly - from quantum dynamics. Although it is hard to know
just how much credence to give this line of thought, it does motivate a
stronger and more comprehensive programme of quantum experiments involving
quantum observers.


title: Quantum Reality via Late Time Photodetection

abstract:
  We further investigate postulates for realist versions of relativistic
quantum theory and quantum field theory in Minkowski space and other background
space-times. According to these postulates, quantum theory is supplemented by
local variables that depend on possible outcomes of hypothetical measurements
on the late time electromagnetic field in spacelike separated regions. We
illustrate the implications in simple examples using photon wave mechanics, and
discuss possible extensions to quantum field theory.


title: An instrumental puzzle: the modular integration of AOLI

abstract:
  The Adaptive Optics Lucky Imager, AOLI, is an instrument developed to deliver
the highest spatial resolution ever obtained in the visible, 20 mas, from
ground-based telescopes. In AOLI a new philosophy of instrumental prototyping
has been applied, based on the modularization of the subsystems. This modular
concept offers maximum flexibility regarding the instrument, telescope or the
addition of future developments.


title:
Commissioning and First Observations with Wide FastCam at the Telescopio
  Carlos S\'anchez

abstract:
  The FastCam instrument platform, jointly developed by the IAC and the UPCT,
allows, in real-time, acquisition, selection and storage of images with a
resolution that reaches the diffraction limit of medium-sized telescopes.
FastCam incorporates a specially designed software package to analyse series of
tens of thousands of images in parallel with the data acquisition at the
telescope. Wide FastCam is a new instrument that, using the same software for
data acquisition, does not look for lucky imaging but fast observations in a
much larger field of view. Here we describe the commissioning process and first
observations with Wide FastCam at the Telescopio Carlos S\'anchez (TCS) in the
Observatorio del Teide.


title:
Learning Latent Local Conversation Modes for Predicting Community
  Endorsement in Online Discussions

abstract:
  Many social media platforms offer a mechanism for readers to react to
comments, both positively and negatively, which in aggregate can be thought of
as community endorsement. This paper addresses the problem of predicting
community endorsement in online discussions, leveraging both the participant
response structure and the text of the comment. The different types of features
are integrated in a neural network that uses a novel architecture to learn
latent modes of discussion structure that perform as well as deep neural
networks but are more interpretable. In addition, the latent modes can be used
to weight text features thereby improving prediction accuracy.


title: Generalizing the Futurama Theorem

abstract:
  The 2010 episode of \emph{Futurama} titled \emph{The Prisoner of Benda}
centers around a machine that swaps the brains of any two people who use it.
The problem is, once two people use the machine to swap brains with each other,
they cannot swap back.
  In this article, we present a new proof of this theorem and also a
generalization of it to what would happen if, instead, the machine swapped
cyclically the brains of $p$ characters, where $p$ is prime.


title: Curvature Free Rigidity for Higher Rank Three-Manifolds

abstract:
  We prove two rigidity results for complete Riemannian three-manifolds of
higher rank. Complete three-manifolds have higher spherical rank if an only if
they are spherical space forms. Complete finite volume three-manifolds have
higher hyperbolic rank if and only if they are hyperbolic space forms.


title:
Spin-orbit precession for eccentric black hole binaries at first order
  in the mass ratio

abstract:
  We consider spin-orbit ("geodetic") precession for a compact binary in
strong-field gravity. Specifically, we compute $\psi$, the ratio of the
accumulated spin-precession and orbital angles over one radial period, for a
spinning compact body of mass $m_1$ and spin $s_1$, with $s_1 \ll G m_1^2/c$,
orbiting a non-rotating black hole. We show that $\psi$ can be computed for
eccentric orbits in both the gravitational self-force and post-Newtonian
frameworks, and that the results appear to be consistent. We present a
post-Newtonian expansion for $\psi$ at next-to-next-to-leading order, and a
Lorenz-gauge gravitational self-force calculation for $\psi$ at first order in
the mass ratio. The latter provides new numerical data in the strong-field
regime to inform the Effective One-Body model of the gravitational two-body
problem. We conclude that $\psi$ complements the Detweiler redshift $z$ as a
key invariant quantity characterizing eccentric orbits in the gravitational
two-body problem.


title: Monotone Paths in Geometric Triangulations

abstract:
  (I) We prove that the (maximum) number of monotone paths in a geometric
triangulation of $n$ points in the plane is $O(1.7864^n)$. This improves an
earlier upper bound of $O(1.8393^n)$; the current best lower bound is
$\Omega(1.7003^n)$.
  (II) Given a planar geometric graph $G$ with $n$ vertices, we show that the
number of monotone paths in $G$ can be computed in $O(n^2)$ time.


title:
Quality Gain Analysis of the Weighted Recombination Evolution Strategy
  on General Convex Quadratic Functions

abstract:
  Quality gain is the expected relative improvement of the function value in a
single step of a search algorithm. Quality gain analysis reveals the
dependencies of the quality gain on the parameters of a search algorithm, based
on which one can derive the optimal values for the parameters. In this paper,
we investigate evolution strategies with weighted recombination on general
convex quadratic functions. We derive a bound for the quality gain and two
limit expressions of the quality gain. From the limit expressions, we derive
the optimal recombination weights and the optimal step-size, and find that the
optimal recombination weights are independent of the Hessian of the objective
function. Moreover, the dependencies of the optimal parameters on the dimension
and the population size are revealed. Differently from previous works where the
population size is implicitly assumed to be smaller than the dimension, our
results cover the population size proportional to or greater than the
dimension. Numerical simulation shows that the asymptotically optimal step-size
well approximates the empirically optimal step-size for a finite dimensional
convex quadratic function.


title: A simple proof of Renner's exponential de Finetti theorem

abstract:
  We give a simple proof of the exponential de Finetti theorem due to Renner.
Like Renner's proof, ours combines the post-selection de Finetti theorem, the
Gentle Measurement lemma, and the Chernoff bound, but avoids virtually all
calculations, including any use of the theory of types.


title:
A Functional Package for Automatic Solution of Ordinary Differential
  Equations with Spectral Methods

abstract:
  We present a Python module named PyCheb, to solve the ordinary differential
equations by using spectral collocation method. PyCheb incorporates
discretization using Chebyshev points, barycentric interpolation and iterate
methods. With this Python module, users can initialize the ODEsolver class by
passing attributes, including the both sides of a given differential equation,
boundary conditions, and the number of Chebyshev points, which can also be
generated automatically by the ideal precision, to the constructor of ODEsolver
class. Then, the instance of the ODEsolver class can be used to automatically
determine the resolution of the differential equation as well as generate the
graph of the high-precision approximate solution. (If you have any questions,
please send me an email and I will reply ASAP.
e-mail:shaohui_liu@qq.com/2013141482143@stu.scu.edu.cn)


title:
NonLERFness of arithmetic hyperbolic manifold groups and mixed
  3-manifold groups

abstract:
  We will show that, for any noncompact arithmetic hyperbolic $m$-manifold with
$m> 3$, and any compact arithmetic hyperbolic $m$-manifold with $m> 4$ that is
not a $7$-dimensional arithmetic hyperbolic manifold defined by octonions, its
fundamental group is not LERF. The main ingredient in the proof is a study on
abelian amalgamations of hyperbolic $3$-manifold groups. We will also show that
a compact orientable irreducible $3$-manifold with empty or tori boundary
supports a geometric structure if and only if its fundamental group is LERF.


title:
Consequences of R-Parity violating interactions for anomalies in $\bar
  B\to D^{(*)} \tau \bar \nu$ and $b\to s \mu^+\mu^-$

abstract:
  We investigate the possibility of explaining the enhancement in semileptonic
decays of $\bar B \to D^{(*)} \tau \bar \nu$, the anomalies induced by $b\to
s\mu^+\mu^-$ in $\bar B\to (K, K^*, \phi)\mu^+\mu^-$ and violation of lepton
universality in $R_K = Br(\bar B\to K \mu^+\mu^-)/Br(\bar B\to K e^+e^-)$
within the framework of R-parity violating (RPV) MSSM. Exchange of down type
right-handed squark coupled to quarks and leptons yield interactions which are
similar to leptoquark induced interactions that have been proposed to explain
the $\bar B \to D^{(*)} \tau \bar \nu$ by tree level interactions and $b\to s
\mu^+\mu^-$ anomalies by loop induced interactions, simultaneously. However,
the Yukawa couplings in such theories have severe constraints from other rare
processes in $B$ and $D$ decays. Although this interaction can provide a viable
solution to $R(D^{(*)})$ anomaly, we show that with the severe constraint from
$\bar B \to K \nu \bar \nu$, it is impossible to solve the anomalies in $b\to s
\mu^+\mu^-$ process simultaneously.


title:
Approximate transformations of bipartite pure-state entanglement from
  the majorization lattice

abstract:
  We study the problem of deterministic transformations of an \textit{initial}
pure entangled quantum state, $|\psi\rangle$, into a \textit{target} pure
entangled quantum state, $|\phi\rangle$, by using \textit{local operations and
classical communication} (LOCC). A celebrated result of Nielsen [Phys. Rev.
Lett. \textbf{83}, 436 (1999)] gives the necessary and sufficient condition
that makes this entanglement transformation process possible. Indeed, this
process can be achieved if and only if the majorization relation $\psi \prec
\phi$ holds, where $\psi$ and $\phi$ are probability vectors obtained by taking
the squares of the Schmidt coefficients of the initial and target states,
respectively. In general, this condition is not fulfilled. However, one can
look for an \textit{approximate} entanglement transformation. Vidal \textit{et.
al} [Phys. Rev. A \textbf{62}, 012304 (2000)] have proposed a deterministic
transformation using LOCC in order to obtain a target state
$|\chi^\mathrm{opt}\rangle$ most approximate to $|\phi\rangle$ in terms of
maximal fidelity between them. Here, we show a strategy to deal with
approximate entanglement transformations based on the properties of the
\textit{majorization lattice}. More precisely, we propose as approximate target
state one whose Schmidt coefficients are given by the supremum between $\psi$
and $\phi$. Our proposal is inspired on the observation that fidelity does not
respect the majorization relation in general. Remarkably enough, we find that
for some particular interesting cases, like two-qubit pure states or the
entanglement concentration protocol, both proposals are coincident.


title: Parameter Selection for HOTV Regularization

abstract:
  Popular methods for finding regularized solutions to inverse problems include
sparsity promoting $\ell_1$ regularization techniques, one in particular which
is the well known total variation (TV) regularization. More recently, several
higher order (HO) methods similar to TV have been proposed, which we generally
refer to as HOTV methods. In this letter, we investigate problem of the often
debated selection of $\lambda$, the parameter used to carefully balance the
interplay between data fitting and regularization terms. We theoretically argue
for a scaling of the parameter that works for all orders for HOTV methods,
based off of a single selection of the parameter for any one of the orders. We
also provide numerical results which justify our theoretical findings.


title: On the Asymptotic Equivalence of Circulant and Toeplitz Matrices

abstract:
  Any sequence of uniformly bounded $N\times N$ Hermitian Toeplitz matrices
$\{\boldsymbol{H}_N\}$ is asymptotically equivalent to a certain sequence of
$N\times N$ circulant matrices $\{\boldsymbol{C}_N\}$ derived from the Toeplitz
matrices in the sense that $\left\| \boldsymbol{H}_N - \boldsymbol{C}_N
\right\|_F = o(\sqrt{N})$ as $N\rightarrow \infty$. This implies that certain
collective behaviors of the eigenvalues of each Toeplitz matrix are reflected
in those of the corresponding circulant matrix and supports the utilization of
the computationally efficient fast Fourier transform (instead of the
Karhunen-Lo\`{e}ve transform) in applications like coding and filtering. In
this paper, we study the asymptotic performance of the individual eigenvalue
estimates. We show that the asymptotic equivalence of the circulant and
Toeplitz matrices implies the individual asymptotic convergence of the
eigenvalues for certain types of Toeplitz matrices. We also show that these
estimates asymptotically approximate the largest and smallest eigenvalues for
more general classes of Toeplitz matrices.


title:
Isomerism in Quantum Dots: Geometries, Band Gaps, Dipole Moments,
  Ionization Energies and Heats of Formation

abstract:
  Quantum dots (QDs) are applied in a variety of fields ranging from
photovoltaics to biomedical imaging. Even the smallest QDs present a
complicated potential energy surface characterized by a large set of stationary
points. Each local minimum is an isomer of QD of given composition. An
established theoretical methodology is hereby employed to obtain geometries of
the QD isomers (Cd16Se16, Cd16Se16, Zn16S16, Zn16Se16) and predict their
fundamental electronic and thermodynamic properties. Significantly scattered
heats of formation, with an amplitude up to 1304 kcal mol-1 in Cd16S16, were
found for the most and the least thermodynamically stable isomers of QDs. The
most shallow transition points can unlikely be observed in the experiments at
finite temperature, since they are able to transform into more stable isomers
upon thermal motion. Dipole moment is the most sensitive property to the QD
isomer geometry. A global energy search technique was demonstrated to be an
efficient tool to systematically identify isomers of QDs.


title:
Recovering Fine Details from Under-Resolved Electron Tomography Data
  using HOTV Regularization

abstract:
  Over the last decade or so, reconstruction methods using $\ell_1$
regularization, often categorized as compressed sensing (CS) algorithms, have
significantly improved the capabilities of high fidelity imaging in electron
tomography. The most popular $\ell_1$ regularization approach within electron
tomography has been total variation (TV) regularization. In addition to
reducing unwanted noise, TV regularization encourages a piecewise constant
solution with sparse boundary regions. In this paper we propose an alternative
$\ell_1$ regularization approach for electron tomography based on higher order
total variation (HOTV). Like TV, the HOTV approach promotes solutions with
sparse boundary regions. In smooth regions however, the solution is not limited
to piecewise constant behavior. We demonstrate that this allows for more
accurate reconstruction of a broader class of images -- even those for which TV
was designed for -- particularly when dealing with pragmatic tomographic
sampling patterns and very fine image features. We develop results for an
electron tomography data set as well as a phantom example, and we also make
comparisons with discrete tomography approaches.


title: Plasma heating inside ICMEs by Alfvenic fluctuations dissipation

abstract:
  Nonlinear cascade of low-frequency Alfvenic fluctuations (AFs) is regarded as
one candidate of the energy sources to heat plasma during the non-adiabatic
expansion of interplanetary coronal mass ejections (ICMEs). However, AFs inside
ICMEs were seldom reported in the literature. In this study, we investigate AFs
inside ICMEs using observations from Voyager 2 between 1 and 6 au. It is found
that AFs with high degree of Alfvenicity frequently occurred inside ICMEs, for
almost all the identified ICMEs (30 out of 33 ICMEs), and 12.6% of ICME time
interval. As ICMEs expand and move outward, the percentage of AF duration
decays linearly in general. The occurrence rate of AFs inside ICMEs is much
less than that in ambient solar wind, especially within 4 au. AFs inside ICMEs
are more frequently presented in the center and at the boundaries of ICMEs. In
addition, the proton temperature inside ICME has a similar distribution. These
findings suggest significant contribution of AFs on local plasma heating inside
ICMEs.


title: Noise and Function

abstract:
  Noise is widely understood to be something that interferes with a signal or
process. Thus, it is generally thought to be destructive, obscuring signals and
interfering with function. However, early in the 20th century, mechanical
engineers found that mechanisms inducing additional vibration in mechanical
systems could prevent sticking and hysteresis. This so-called "dither" noise
was later introduced in an entirely different context at the advent of digital
information transmission and recording in the early 1960s. Ironically, the
addition of noise allows one to preserve information that would otherwise be
lost when the signal or image is digitized. As we shall see, the benefits of
added noise in these contexts are closely related to the phenomenon which has
come to be known as stochastic resonance, the original version of which
appealed to noise to explain how small periodic fluctuations in the
eccentricity of the earth's orbit might be amplified in such a way as to bring
about the observed periodic transitions in climate from ice age to temperate
age and back. These noise-induced transitions have since been invoked to
explain a wide array of biological phenomena, including the foraging and
tracking behavior of ants. Many biological phenomena, from foraging to gene
expression, are noisy, involving an element of randomness. In this paper, we
illustrate the general principles behind dithering and stochastic resonance
using examples from image processing, and then show how the constructive use of
noise can carry over to systems found in nature.


title:
Spectral Theory Sum Rules, Meromorphic Herglotz Functions and Large
  Deviations

abstract:
  Short blurb for invited talk at AMS annual meeting in Atlanta; will appear in
January AMS Notices


title:
A better convergence analysis of the block coordinate descent method for
  large scale machine learning

abstract:
  This paper considers the problems of unconstrained minimization of large
scale smooth convex functions having block-coordinate-wise Lipschitz continuous
gradients. The block coordinate descent (BCD) method are among the first
optimization schemes suggested for solving such problems
\cite{nesterov2012efficiency}. We obtain a new lower (to our best knowledge the
lowest currently) bound that is $16p^3$ times smaller than the best known on
the information-based complexity of BCD method based on an effective technique
called Performance Estimation Problem (PEP) proposed by Drori and Teboulle
\cite{drori2012performance} recently for analyzing the performance of
first-order black box optimization methods. Numerical test confirms our
analysis.


title:
Well-Posedness of some nonlinear Volterra-Fredholm integral and
  integro-dynamic equations on time scales

abstract:
  In this paper we study well posedness of a certain nonlinear
Volterra-Fredholm dynamic integral and integro-dynamic equations on unbounded
interval from arbitrary time scale. We derive the time scale analogue of
certain integral inequalities of Pachpatte type and using them with Banach's
fixed-point theorem to establish the results.


title: Localized waves supported by the rotating waveguide array

abstract:
  We show that truncated rotating square waveguide arrays support new types of
localized modes that exist even in the linear case, in complete contrast to
localized excitations in nonrotating arrays requiring nonlinearity for their
existence and forming above the energy flow threshold. These new modes appear
either around array center, since rotation leads to the emergence of the
effective attractive potential with a minimum at the rotation axis, or in the
array corners, in which case localization occurs due to competition between
centrifugal force (in terms of quasi-particle analogy) and total internal
reflection at the interface of the truncated array. The degree of localization
of the central and corner modes mediated by rotation increases with rotation
frequency. Stable rotating soliton families bifurcating from linear modes are
analyzed in both focusing and defocusing media.


title: Quantum Merlin-Arthur with noisy channel

abstract:
  What happens if in QMA the quantum channel between Merlin and Arthur is
noisy? It is not difficult to show that such a modification does not change the
computational power as long as the noise is not too strong so that errors are
correctable with high probability, since if Merlin encodes the witness state in
a quantum error-correction code and sends it to Arthur, Arthur can correct the
error caused by the noisy channel. If we further assume that Arthur can do only
single-qubit measurements, however, the problem becomes nontrivial, since in
this case Arthur cannot do the universal quantum computation by himself. In
this paper, we show that such a restricted complexity class is still equivalent
to QMA. To show it, we use measurement-based quantum computing: honest Merlin
sends the graph state to Arthur, and Arthur does fault-tolerant
measurement-based quantum computing on the noisy graph state with only
single-qubit measurements. By measuring stabilizer operators, Arthur also
checks the correctness of the graph state. Although this idea itself was
already used in several previous papers, these results cannot be directly used
to the present case, since the test that checks the graph state used in these
papers is so strict that even honest Merlin is rejected with high probability
if the channel is noisy. We therefore introduce a more relaxed test that can
accept not only the ideal graph state but also noisy graph states that are
error-correctable.


title: Outlier Detection on Mixed-Type Data: An Energy-based Approach

abstract:
  Outlier detection amounts to finding data points that differ significantly
from the norm. Classic outlier detection methods are largely designed for
single data type such as continuous or discrete. However, real world data is
increasingly heterogeneous, where a data point can have both discrete and
continuous attributes. Handling mixed-type data in a disciplined way remains a
great challenge. In this paper, we propose a new unsupervised outlier detection
method for mixed-type data based on Mixed-variate Restricted Boltzmann Machine
(Mv.RBM). The Mv.RBM is a principled probabilistic method that models data
density. We propose to use \emph{free-energy} derived from Mv.RBM as outlier
score to detect outliers as those data points lying in low density regions. The
method is fast to learn and compute, is scalable to massive datasets. At the
same time, the outlier score is identical to data negative log-density up-to an
additive constant. We evaluate the proposed method on synthetic and real-world
datasets and demonstrate that (a) a proper handling mixed-types is necessary in
outlier detection, and (b) free-energy of Mv.RBM is a powerful and efficient
outlier scoring method, which is highly competitive against state-of-the-arts.


title:
Long-range transverse Ising model built with dipolar condensates in
  two-well arrays

abstract:
  Dipolar Bose-Einstein condensates in an array of double-well potentials
realize an effective transverse Ising model with peculiar inter-layer
interactions, that may result under proper conditions in an anomalous
first-order ferromagnetic-antiferromagnetic phase transition, and nontrivial
phases due to frustration. The considered setup as well allows the study of
Kibble-Zurek defect formation, whose kink statistics follows that expected from
the universality class of the mean-field transverse Ising model in 1D.
Furthermore, random occupation of each layer of the stack leads to random
effective Ising interactions and generation of local transverse fields, thus
allowing the study of Anderson-like localization of imbalance perturbations in
the two-well stack under controllable conditions.


title: Monetary economics from econophysics perspective

abstract:
  This is an invited article for the Discussion and Debate special issue of The
European Physical Journal Special Topics on the subject "Can Economics Be a
Physical Science?" The first part of the paper traces the personal path of the
author from theoretical physics to economics. It briefly summarizes
applications of statistical physics to monetary transactions in an ensemble of
economic agents. It shows how a highly unequal probability distribution of
money emerges due to irreversible increase of entropy in the system. The second
part examines deep conceptual and controversial issues and fallacies in
monetary economics from econophysics perspective. These issues include the
nature of money, conservation (or not) of money, distinctions between money vs.
wealth and money vs. debt, creation of money by the state and debt by the
banks, the origins of monetary crises and capitalist profit. Presentation uses
plain language understandable to laypeople and may be of interest to both
specialists and general public.


title: Geometric numerical integrators for Hunter-Saxton-like equations

abstract:
  We present novel geometric numerical integrators for Hunter--Saxton-like
equations by means of new multi-symplectic formulations and known Hamiltonian
structures of the problems. We consider the Hunter--Saxton equation, the
modified Hunter--Saxton equation, and the two-component Hunter--Saxton
equation. Multi-symplectic discretisations based on these new formulations of
the problems are exemplified by means of the explicit Euler box scheme, and
Hamiltonian-preserving discretisations are exemplified by means of the discrete
variational derivative method. We explain and justify the correct treatment of
boundary conditions in a unified manner. This is necessary for a proper
numerical implementation of these equations and was never explicitly clarified
in the literature before, to the best of our knowledge. Finally, numerical
experiments demonstrate the favourable behaviour of the proposed numerical
integrators.


title:
Asymptotic approximation of central binomial coefficients with rigorous
  error bounds

abstract:
  We show that a well-known asymptotic series for the logarithm of the central
binomial coefficient is strictly enveloping in the sense of P\'olya and
Szeg\"o, so the error incurred in truncating the series is of the same sign as
the next term, and is bounded in magnitude by that term. We consider closely
related asymptotic series for Binet's function, for $\ln\Gamma(z+1/2)$, and for
the Riemann-Siegel theta function, and make some historical remarks.


title: Some relations of interpolated multiple zeta values

abstract:
  In this paper, the extended double shuffle relations for interpolated
multiple zeta values are established. As an application, Hoffman's relations
for interpolated multiple zeta values are proved. Furthermore, a generating
function for sums of interpolated multiple zeta values of fixed weight, depth
and height is represented by hypergeometric functions, and we discuss some
special cases.


title: Gravitational collapse of massless scalar field in $f(R)$ gravity

abstract:
  We study the spherically symmetric gravitational collapse of massless scalar
matter field in asymptotic flat spacetime in $f(R)$ gravity. In the Einstein
frame of $f(R)$ gravity, an additional scalar field arises due to the conformal
transformation. We find that besides the usual competition between
gravitational energy and kinetic energy in the process of gravitational
collapse, the new scalar field brought by the conformal transformation adds one
more competing force in the dynamical system. The dynamical competition can be
controlled by tuning the amplitudes of the initial perturbations of the new
scalar field and the matter field. To understand the physical reasons behind
these phenomena, we analyze the gravitational potential behavior and calculate
the Ricci scalar at center with the change of initial amplitudes of
perturbations. We find rich physics on the formation of black holes through
gravitational collapse in $f(R)$ gravity.


title:
I-Planner: Intention-Aware Motion Planning Using Learning Based Human
  Motion Prediction

abstract:
  We present a motion planning algorithm to compute collision-free and smooth
trajectories for high-DOF robots interacting with humans in a shared workspace.
Our approach uses offline learning of human actions along with temporal
coherence to predict the human actions. Our intention-aware online planning
algorithm uses the learned database to compute a reliable trajectory based on
the predicted actions. We represent the predicted human motion using a Gaussian
distribution and compute tight upper bounds on collision probabilities for safe
motion planning. We also describe novel techniques to account for noise in
human motion prediction. We highlight the performance of our planning algorithm
in complex simulated scenarios and real world benchmarks with 7-DOF robot arms
operating in a workspace with a human performing complex tasks. We demonstrate
the benefits of our intention-aware planner in terms of computing safe
trajectories in such uncertain environments.


title: Almost perfect matchings in $k$-partite $k$-graphs

abstract:
  The minimum co-degree threshold for a perfect matching in a $k$-graph with
$n$ vertices was determined by R\"odl, Ruci\'nski and Szemer\'edi for the case
when $n\equiv 0\pmod k$. Recently, Han resolved the remaining cases when $n
\not\equiv 0\pmod k$, establishing a conjecture of R\"odl, Ruci\'nski and
Szemer\'edi. In this paper, we determine the minimum co-degree threshold for
almost perfect matchings in $k$-partite $k$-graphs, answering a question of
R\"odl and Ruci\'nski.


title: Dynamic Collaborative Filtering with Compound Poisson Factorization

abstract:
  Model-based collaborative filtering analyzes user-item interactions to infer
latent factors that represent user preferences and item characteristics in
order to predict future interactions. Most collaborative filtering algorithms
assume that these latent factors are static, although it has been shown that
user preferences and item perceptions drift over time. In this paper, we
propose a conjugate and numerically stable dynamic matrix factorization (DCPF)
based on compound Poisson matrix factorization that models the smoothly
drifting latent factors using Gamma-Markov chains. We propose a numerically
stable Gamma chain construction, and then present a stochastic variational
inference approach to estimate the parameters of our model. We apply our model
to time-stamped ratings data sets: Netflix, Yelp, and Last.fm, where DCPF
achieves a higher predictive accuracy than state-of-the-art static and dynamic
factorization models.


title:
Emergent elasticity of skyrmion crystal in chiral magnets: the
  constitutive equations

abstract:
  Here we derive the linear constitutive equations governing the emergent
elastic behavior of skX under applied mechanical forces as well as other
effective fields. The linear coefficients appearing in the equations are
expressed analytically in terms of the thermodynamic parameters describing the
magnetoelastic interaction of the underlying chiral magnet. Through the
deduction of equations, we clarify that two types of coupled deformation may
occur for skX, that is the internal deformation, described by variation of the
Fourier magnitudes, and the lattice deformation, described by the emergent
elastic strains. We also find that besides mechanical loads, bias magnetic
field, spatially periodic magnetic field, spatially periodic mechanical loads,
and emergent stresses can all lead to deformation of the skX. When homogeneous
stresses are applied only, the emergent elastic strains are linearly related to
the elastic strains through the emergent strain ratio matrix {\lambda}. We
calculate {\lambda} for the skX in bulk MnSi and discuss its variation with the
temperature and magnetic field. In particular, we find that all components of
{\lambda} are sensitive to variation of magnetic field b, such that they change
sign as b increases. Moreover, as b approaches the critical magnetic field of
the skX-ferromagnetic phase transition, the dominant components of {\lambda}
diverges. The constitutive equations are of fundamental significance in
emergent elasticity, a new area studying the variation of internal forces and
deformation of emergent crystals and their relation when exposed to effective
external fields.


title:
Safe Serializable Secure Scheduling: Transactions and the Trade-off
  Between Security and Consistency

abstract:
  Modern applications often operate on data in multiple administrative domains.
In this federated setting, participants may not fully trust each other. These
distributed applications use transactions as a core mechanism for ensuring
reliability and consistency with persistent data. However, the coordination
mechanisms needed for transactions can both leak confidential information and
allow unauthorized influence.
  By implementing a simple attack, we show these side channels can be
exploited. However, our focus is on preventing such attacks. We explore secure
scheduling of atomic, serializable transactions in a federated setting. While
we prove that no protocol can guarantee security and liveness in all settings,
we establish conditions for sets of transactions that can safely complete under
secure scheduling. Based on these conditions, we introduce staged commit, a
secure scheduling protocol for federated transactions. This protocol avoids
insecure information channels by dividing transactions into distinct stages. We
implement a compiler that statically checks code to ensure it meets our
conditions, and a system that schedules these transactions using the staged
commit protocol. Experiments on this implementation demonstrate that realistic
federated transactions can be scheduled securely, atomically, and efficiently.


title: What can the outskirts of galaxies tell us about dark matter?

abstract:
  Deep observations of galaxy outskirts reveal faint extended stellar
components (ESCs) of streams, shells, and halos, which are ghostly remnants of
the tidal disruption of satellite galaxies. We use cosmological galaxy
formation simulations in Cold Dark Matter (CDM) and Warm Dark Matter (WDM)
models to explore how the dark matter model influences the spatial, kinematic,
and orbital properties of ESCs. These reveal that the spherically averaged
stellar mass density at large galacto-centric radius can be depressed by up to
a factor of 10 in WDM models relative to the CDM model, reflecting the
anticipated suppressed abundance of satellite galaxies in WDM models. However,
these differences are much smaller in WDM models that are compatible with
observational limits, and are comparable in size to the system-to-system
variation we find within the CDM model. This suggests that it will be
challenging to place limits on dark matter using only the unresolved ESC.


title: Putting Down Roots: A Graphical Exploration of Community Attachment

abstract:
  In this paper, we explore the relationships that individuals have with their
communities. This work was prepared as part of the ASA Data Expo '13 sponsored
by the Graphics Section and the Computing Section, using data provided by the
Knight Foundation Soul of the Community survey. The Knight Foundation in
cooperation with Gallup surveyed 43,000 people over three years in 26
communities across the United States with the intention of understanding the
association between community attributes and the degree of attachment people
feel towards their community. These include the different facets of both urban
and rural communities, the impact of quality education, and the trend in the
perceived economic conditions of a community over time. The goal of our work is
to facilitate understanding of why people feel attachment to their communities
through the use of an interactive and web-based visualization. We will explain
the development and use of web-based interactive graphics, including an
overview of the R package Shiny and the JavaScript library D3, focusing on the
choices made in producing the visualizations and technical aspects of how they
were created. Then we describe the stories about community attachment that
unfolded from our analysis.


title: Boosting Docking-based Virtual Screening with Deep Learning

abstract:
  In this work, we propose a deep learning approach to improve docking-based
virtual screening. The introduced deep neural network, DeepVS, uses the output
of a docking program and learns how to extract relevant features from basic
data such as atom and residues types obtained from protein-ligand complexes.
Our approach introduces the use of atom and amino acid embeddings and
implements an effective way of creating distributed vector representations of
protein-ligand complexes by modeling the compound as a set of atom contexts
that is further processed by a convolutional layer. One of the main advantages
of the proposed method is that it does not require feature engineering. We
evaluate DeepVS on the Directory of Useful Decoys (DUD), using the output of
two docking programs: AutodockVina1.1.2 and Dock6.6. Using a strict evaluation
with leave-one-out cross-validation, DeepVS outperforms the docking programs in
both AUC ROC and enrichment factor. Moreover, using the output of
AutodockVina1.1.2, DeepVS achieves an AUC ROC of 0.81, which, to the best of
our knowledge, is the best AUC reported so far for virtual screening using the
40 receptors from DUD.


title: Lecture Notes on Spectral Graph Methods

abstract:
  These are lecture notes that are based on the lectures from a class I taught
on the topic of Spectral Graph Methods at UC Berkeley during the Spring 2015
semester.


title: A Convolutional Autoencoder for Multi-Subject fMRI Data Aggregation

abstract:
  Finding the most effective way to aggregate multi-subject fMRI data is a
long-standing and challenging problem. It is of increasing interest in
contemporary fMRI studies of human cognition due to the scarcity of data per
subject and the variability of brain anatomy and functional response across
subjects. Recent work on latent factor models shows promising results in this
task but this approach does not preserve spatial locality in the brain. We
examine two ways to combine the ideas of a factor model and a searchlight based
analysis to aggregate multi-subject fMRI data while preserving spatial
locality. We first do this directly by combining a recent factor method known
as a shared response model with searchlight analysis. Then we design a
multi-view convolutional autoencoder for the same task. Both approaches
preserve spatial locality and have competitive or better performance compared
with standard searchlight analysis and the shared response model applied across
the whole brain. We also report a system design to handle the computational
challenge of training the convolutional autoencoder.


title:
A mathematical model for mechanically-induced deterioration of the
  binder in lithium-ion electrodes

abstract:
  This study is concerned with modeling detrimental deformations of the binder
phase within lithium-ion batteries that occur during cell assembly and usage. A
two-dimensional poroviscoelastic model for the mechanical behavior of porous
electrodes is formulated and posed on a geometry corresponding to a thin
rectangular electrode, with a regular square array of microscopic circular
electrode particles, stuck to a rigid base formed by the current collector.
Deformation is forced both by (i) electrolyte absorption driven binder
swelling, and; (ii) cyclic growth and shrinkage of electrode particles as the
battery is charged and discharged. The governing equations are upscaled in
order to obtain macroscopic effective-medium equations. A solution to these
equations is obtained, in the asymptotic limit that the height of the
rectangular electrode is much smaller than its width, that shows the
macroscopic deformation is one-dimensional. The confinement of macroscopic
deformations to one dimension is used to obtain boundary conditions on the
microscopic problem for the deformations in a 'unit cell' centered on a single
electrode particle. The resulting microscale problem is solved using numerical
(finite element) techniques. The two different forcing mechanisms are found to
cause distinctly different patterns of deformation within the microstructure.
Swelling of the binder induces stresses that tend to lead to binder
delamination from the electrode particle surfaces in a direction parallel to
the current collector, whilst cycling causes stresses that tend to lead to
delamination orthogonal to that caused by swelling. The differences between the
cycling-induced damage in both: (i) anodes and cathodes, and; (ii) fast and
slow cycling are discussed. Finally, the model predictions are compared to
microscopy images of nickel manganese cobalt oxide cathodes and a qualitative
agreement is found.


title:
Proximity induced superconductivity in monolayer CuO$_{2}$ on the
  cuprate substrates

abstract:
  To understand the recently observed high temperature superconductivity in the
monolayer CuO$_2$ grown on the Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ substrates,
we propose a two band model of the hybridized oxygen $p_x$ and $p_y$ orbitals
with the proximity effect of the substrate. We demonstrate that both the nodal
and nodeless d-wave superconducting states can be induced by the proximity
effect, depending on the strengths of the pairing parameters.


title: Dressed-state scheme for a fast CNOT gate

abstract:
  A highly feasible dressed-state scheme, which greatly speeds up the adiabatic
population transfer of a quantum system, is applied for implementing a fast
CNOT gate in a cavity QED system. The cavity QED system consists of two
identical five-level atoms which are respectively trapped in two optical
cavities connected by a fiber. With the help of quantum Zeno dynamics, the CNOT
gate is constructed by three steps with six pulses. Because the adiabatic
condition is not necessary to be considered and all of the pulses are smoothly
turned on and off, the scheme is fast and feasible in experiment. Numerical
simulations indicate that the average fidelity for constructing the CNOT gate
is quite high and the gate operation time is relatively short. Moreover, the
effects on the fidelity of the atomic spontaneous emission and the photon
leakages from the cavities are discussed by the master equation and the result
shows the scheme is robust against the decoherence.


title: Sliding control for single-degree-of-freedom fractional oscillators

abstract:
  This paper proposes fractional sliding control designs for
single-degree-of-freedom fractional oscillators respectively of the
Kelvin-Voigt type, the modified Kelvin-Voigt type and D\"{u}ffing type, whose
dynamical behaviors are described by second-order differential equations
involving fractional derivatives. Firstly, the differential equations of motion
are transformed into non-commensurate fractional state equations by introducing
state variables with physical significance. Secondly, fractional sliding
manifolds are constructed and stability of the corresponding sliding dynamics
is addressed via the infinite state approach and Lyapunov stability theory.
Thirdly, sliding control laws and adaptive sliding laws are designed for
fractional oscillators respectively in cases that the bound of the external
exciting force is known or unknown. Finally, numerical simulations are carried
out to validate the above control designs.


title:
Essentials of an Integrated Crowd Management Support System Based on
  Collective Artificial Intelligence

abstract:
  The simulation of the dynamical behavior of pedestrians and crowds in spatial
structures is a consolidated research and application context that still
presents challenges for researchers in different fields and disciplines.
Despite currently available commercial systems for this kind of simulation are
growingly employed by designers and planners for the evaluation of alternative
solutions, this class of systems is generally not integrated with existing
monitoring and control infrastructures, usually employed by crowd managers and
field operators for security reasons. This paper introduces the essentials and
the related computational frame- work of an Integrated Crowd Management Support
System based on a Collective Artificial Intelligence approach encompassing (i)
interfaces from and to monitored and controlled environments (respectively,
sen- sors and actuators), (ii) a set of software tools supporting the analysis
of pedestrians and crowd phenomena taking place in the environment to feed a
(iii) faster than real-time simulation of the plausible evolution of the
current situation in order to support forms of inference provid- ing decision
support to crowd managers, potentially directly controlling elements of the
environment (e.g. blocking turnstiles, escalators), com- municating orders to
operators on the field or trying to influence the pedestrians by means of
dynamic signage or audible messages.


title: Quicksort with median of medians is considered practical

abstract:
  The linear pivot selection algorithm, known as median-of-medians, makes the
worst case complexity of quicksort be $\mathrm{O}(n\ln n)$. Nevertheless, it
has often been said that this algorithm is too expensive to use in quicksort.
In this article, we show that we can make the quicksort with this kind of pivot
selection approach be efficient.


title:
Dynamic heterogeneities and non-Gaussian behavior in two-dimensional
  randomly confined colloidal fluids

abstract:
  A binary mixture of super-paramagnetic colloidal particles is confined
between glass plates such that the large particles become fixed and provide a
two-dimensional disordered matrix for the still mobile small particles, which
form a fluid. By varying fluid and matrix area fractions and tuning the
interactions between the super-paramagnetic particles via an external magnetic
field, different regions of the state diagram are explored. The mobile
particles exhibit delocalized dynamics at small matrix area fractions and
localised motion at high matrix area fractions, and the localization transition
is rounded by the soft interactions [T. O. E. Skinner et al, Phys. Rev. Lett.
{\bf 111}, 128301 (2013)]. Expanding on previous work, we find the dynamics of
the tracers to be strongly heterogeneous and show that molecular dynamics
simulations of an ideal gas confined in a fixed matrix exhibit similar
behavior. The simulations show how these soft interactions make the dynamics
more heterogenous compared to the disordered Lorentz gas and lead to strong
non-Gaussian fluctuations.


title:
Green's functions for spin boson systems: Beyond conventional
  perturbation theories

abstract:
  Unraveling general properties of Green's functions of quantum dissipative
systems is of both experimental relevance and theoretical interest. Here, we
study the spin-boson model as a prototype. By utilizing the Majorana- Fermion
representation together with the polaron transformation, we establish a
theoretical approach to analyze Green's functions of the spin-boson model. In
contrast to conventional perturbation theories either in the tunneling energy
or in the system-bath coupling strength, the proposed scheme gives reliable
results over wide regimes of the coupling strength, bias, as well as
temperature. To demonstrate the utility of the approach, we consider the
susceptibility as well as the symmetrized spin correlation function (SSCF)
which can be expressed in terms of Green's functions. Thorough investigations
are made on systems embedded in Ohmic or sub-Ohmic bosonic baths. We found the
so-obtained SSCF is the same as that of the non-interacting blip approximation
(NIBA) in unbiased systems while it is applicable for a wider range of
temperature in the biased systems compared with the NIBA. We also show that a
previous perturbation result is recovered as a weak coupling limit of the
so-obtained SSCF. Furthermore, by studying the quantum criticality of the
susceptibility, we confirm the validity of the quantum-toclassical mapping in
the whole sub-Ohmic regime.


title:
First study of the CP-violating phase and decay-width difference in
  $B_s^0\to\psi(2S)\phi$ decays

abstract:
  A time-dependent angular analysis of $B_s^0\to\psi(2S)\phi$ decays is
performed using data recorded by the LHCb experiment. The data set corresponds
to an integrated luminosity of 3.0\invfb collected during Run 1 of the LHC. The
CP-violating phase and decay-width difference of the $B_s^0$ system are
measured to be $\phi_s = 0.23^{+0.29}_{-0.28} \pm 0.02$ rad and $\Delta\Gamma_s
= 0.066^{+0.041}_{-0.044} \pm 0.007$ ps$^{-1}$, respectively, where the first
uncertainty is statistical and the second systematic. This is the first time
that $\phi_s$ and $\Delta\Gamma_s$ have been measured in a decay containing the
$\psi(2S)$ resonance.


title: Nature of charmed strange baryons $\Xi_c(3055)$ and $\Xi_c(3080)$

abstract:
  The hadronic decay widths and some ratios of branching fractions of the newly
observed charmed strange baryons, $\Xi_c(3055)^0$, $\Xi_c(3055)^+$ and
$\Xi_c(3080)^+$ are calculated in a $^3P_0$ model. In the calculation, they are
considered as $34$ kinds of $D-wave$ charmed strange baryons. Among these
assignments, $\Xi_c(3055)^+$ is very possibly a $J^P={5\over 2}^+$
$\hat\Xi_{c3}^\prime(\frac{5}{2}^+)$ or $\check\Xi_{c3}^2(\frac{5}{2}^+)$,
where $\Xi_c(3055)^+$ has the total decay width $\Gamma=10.1$ MeV and
$\Gamma=7.6$ MeV. The predicted ratios $\Gamma(\Xi_c(3055)^+ \to \Lambda D^+ )/
\Gamma(\Xi_c(3055)^+ \to \Sigma_c^{++}K^-)=3.39$. $\Xi_c(3055)^+$ is also very
possibly a $J^P={7\over 2}^+$ $\hat\Xi_{c3}^\prime(\frac{7}{2}^+)$ or
$\check\Xi_{c3}^2(\frac{7}{2}^+)$. In these two assignments, $\Xi_c(3055)^+$
has the total decay width $\Gamma=9.7$ MeV and $\Gamma=6.3$ MeV. The predicted
ratios $\Gamma(\Xi_c(3055)^+ \to \Lambda D^+ )/ \Gamma(\Xi_c(3055)^+ \to
\Sigma_c^{++}K^-)=5.91~\rm{or}~6.04$. As a isospin partner of $\Xi_c(3055)^+$,
$\Xi_c(3055)^0$ is also very possibly a $J^P={5\over 2}^+$
$\hat\Xi_{c3}^\prime(\frac{5}{2}^+)$ or $\check\Xi_{c3}^2(\frac{5}{2}^+)$,
where $\Xi_c(3055)^0$ has the total decay width $\Gamma=10.9$ MeV and
$\Gamma=7.0$ MeV. The predicted ratios $\Gamma(\Xi_c(3055)^0 \to \Lambda D^0 )/
\Gamma(\Xi_c(3055)^0 \to \Sigma_c^{+}K^-)=4.24~\rm{or}~4.20$. $\Xi_c(3055)^0$
is also very possibly a $J^P={7\over 2}^+$ $\hat\Xi_{c3}^\prime(\frac{7}{2}^+)$
or $\check\Xi_{c3}^2(\frac{7}{2}^+)$. In these assignments, $\Xi_c(3055)^0$ has
the total decay width $\Gamma=10.3$ MeV and $\Gamma=7.1$ MeV. The predicted
ratios $\Gamma(\Xi_c(3055)^0 \to \Lambda D^0 )/ \Gamma(\Xi_c(3055)^0 \to
\Sigma_c^{+}K^-)=7.47~\rm{or}~7.56$. The results agree well with recent
experimental data from Belle. $\Xi_c(3080)^+$ seems impossible to be identified
with a D-wave charmed strange baryon.


title: Quality adaptive online double auction in participatory sensing

abstract:
  Agents (specially humans) with smart devices are stemming with astounding
rapidity and that may play a big role in information and communication
technology apart from being used only as a mere calling devices. Inculcating
the power of smart devices carried by the agents in several different
applications is commonly termed as participatory sensing (PS). In this paper,
for the first time a truthful quality adaptive participatory sensing is
presented in an online double auction environment. The proposed algorithm is
simulated with a benchmark mechanism that adapts the existing McAfee's Double
Auction (MDA) directly in the online environment.


title: Symmetric identities of higher-order degenerate q-Bernoulli polynomials

abstract:
  The purpose of this paper is to give symmetric identities for higher-order
degenerate q- Bernoulli polynomials arising from the p-adic q-integral on Zp.


title:
Imprimitivity bimodules of Cuntz--Krieger algebras and strong shift
  equivalences of matrices

abstract:
  In this paper, we will introduce a notion of basis related Morita equivalence
in the Cuntz--Krieger algebras $({{\mathcal{O}}_A}, \{S_a\}_{a \in E_A})$ with
the canonical right finite basis $\{S_a\}_{a \in E_A}$ as Hilbert
$C^*$-bimodule, and prove that two nonnegative irreducible matrices $A$ and $B$
are elementary equivalent, that is, $A = CD, B = DC$ for some nonnegative
rectangular matrices $C, D$, if and only if the Cuntz--Krieger algebras
$({{\mathcal{O}}_A}, \{S_a\}_{a \in E_A})$ and $({{\mathcal{O}}_B}, \{
S_b\}_{b\in E_B})$ with the canonical right finite bases are basis relatedly
elementary Morita equivalent.


title: Momentum mapping of continuum electron wave packet interference

abstract:
  We analyze the two-dimensional photoelectrons momentum distribution of Ar
atom ionized by midinfrared laser pulses and mainly concentrate on the energy
range below 2Up. By using a generalized quantum trajectory Monte Carlo (GQTMC)
simulation and comparing with the numerical solution of time-dependent
Schrodinger equation (TDSE), we show that in the deep tunneling regime, the
rescattered electron trajectories plays unimportant role and the interplay
between the intracycle and inter-cycle results in a ring-like interference
pattern. The ring-like interference pattern will mask the holographic
interference structure in the low longitudinal momentum region. When the
nonadiabatic tunneling contributes significantly to ionization, i.e., the
Keldysh parameter 1, the contribution of the rescattered electron trajectories
become large, thus holographic interference pattern can be clearly observed.
Our results help paving the way for gaining physical insight into ultrafast
electron dynamic process with attosecond temporal resolution.


title: Adaptive confidence sets for matrix completion

abstract:
  In the present paper we study the problem of existence of honest and adaptive
confidence sets for matrix completion. We consider two statistical models: the
trace regression model and the Bernoulli model. In the trace regression model,
we show that honest confidence sets that adapt to the unknown rank of the
matrix exist even when the error variance is unknown. Contrary to this, we
prove that in the Bernoulli model, honest and adaptive confidence sets exist
only when the error variance is known a priori. In the course of our proofs we
obtain bounds for the minimax rates of certain composite hypothesis testing
problems arising in low rank inference.


title: Feature Driven and Point Process Approaches for Popularity Prediction

abstract:
  Predicting popularity, or the total volume of information outbreaks, is an
important subproblem for understanding collective behavior in networks. Each of
the two main types of recent approaches to the problem, feature-driven and
generative models, have desired qualities and clear limitations. This paper
bridges the gap between these solutions with a new hybrid approach and a new
performance benchmark. We model each social cascade with a marked Hawkes
self-exciting point process, and estimate the content virality, memory decay,
and user influence. We then learn a predictive layer for popularity prediction
using a collection of cascade history. To our surprise, Hawkes process with a
predictive overlay outperform recent feature-driven and generative approaches
on existing tweet data [43] and a new public benchmark on news tweets. We also
found that a basic set of user features and event time summary statistics
performs competitively in both classification and regression tasks, and that
adding point process information to the feature set further improves
predictions. From these observations, we argue that future work on popularity
prediction should compare across feature-driven and generative modeling
approaches in both classification and regression tasks.


title:
Influence of selfish and polite behaviours on a pedestrian evacuation
  through a narrow exit: A quantitative characterisation

abstract:
  We study the influence of selfish vs. polite behaviours on the dynamics of a
pedestrian evacuation through a narrow exit. To this end, experiments involving
about 80 participants with distinct prescribed behaviours are performed;
reinjection of participants into the setup allowed us to improve the
statistics. Notwithstanding the fluctuations in the instantaneous flow rate, we
find that a stationary regime is almost immediately reached. The average flow
rate increases monotonically with the fraction c\_s of vying (selfish)
pedestrians, which corresponds to a "faster-is-faster" effect in our
experimental conditions; it is also positively correlated with the average
density of pedestrians in front of the door, up to nearly close-packing. At
large c\_s , the flow displays marked intermittency, with bursts of
quasi-simultaneous escapes. In addition to these findings, we wonder whether
the effect of cooperation is specific to systems of intelligent beings, or
whether it can be reproduced by a purely mechanical surrogate. To this purpose,
we consider a bidimensional granular flow through an orifice in which some
grains are made "cooperative" by repulsive magnetic interactions which impede
their mutual collisions.


title:
Sub-exponential decay of eigenfunctions for some discrete Schr\"odinger
  operators

abstract:
  Following the method of Froese and Herbst, we show for a class of potentials
V that an eigenfunction $\psi$ with eigenvalue E of the multi-dimensional
discrete Schr\"odinger operator H = $\Delta$ + V on \mathbb{Z}^d decays
sub-exponentially whenever the Mourre estimate holds at E. In the
one-dimensional case we further show that this eigenfunction decays
exponentially with a rate at least of cosh^{--1}((E -- 2)/($\theta$\_E -- 2)),
where $\theta$\_E is the nearest threshold of H located between E and 2. A
consequence of the latter result is the absence of eigenvalues between 2 and
the nearest thresholds above and below this value. The method of Combes-Thomas
is also reviewed for the discrete Schr\"odinger operators.


title:
Colorimetry technique for scalable characterization of suspended
  graphene

abstract:
  Previous statistical studies on the mechanical properties of
chemical-vapor-deposited (CVD) suspended graphene membranes have been performed
by means of measuring individual devices or with techniques that affect the
material. Here, we present a colorimetry technique as a parallel, non-invasive,
and affordable way of characterizing suspended graphene devices. We exploit
Newton rings interference patterns to study the deformation of a double-layer
graphene drum 13.2 micrometer in diameter when a pressure step is applied. By
studying the time evolution of the deformation, we find that filling the drum
cavity with air is 2-5 times slower than when it is purged.


title:
On the Distinguishing Number of Cyclic Tournaments: Towards the
  Albertson-Collins Conjecture

abstract:
  A distinguishing $r$-labeling of a digraph $G$ is a mapping $\lambda$ from
the set of verticesof $G$ to the set of labels $\{1,\dots,r\}$ such that no
nontrivial automorphism of $G$ preserves all the labels.The distinguishing
number $D(G)$ of $G$ is then the smallest $r$ for which $G$ admits a
distinguishing $r$-labeling.From a result of Gluck (David Gluck, Trivial
set-stabilizers in finite permutation groups,{\em Can. J. Math.} 35(1) (1983),
59--67),it follows that $D(T)=2$ for every cyclic tournament~$T$ of (odd) order
$2q+1\ge 3$.Let $V(T)=\{0,\dots,2q\}$ for every such tournament.Albertson and
Collins conjectured in 1999that the canonical 2-labeling $\lambda^*$ given
by$\lambda^*(i)=1$ if and only if $i\le q$ is distinguishing.We prove that
whenever one of the subtournaments of $T$ induced by vertices $\{0,\dots,q\}$or
$\{q+1,\dots,2q\}$ is rigid, $T$ satisfies Albertson-Collins Conjecture.Using
this property, we prove that several classes of cyclic tournaments satisfy
Albertson-Collins Conjecture.Moreover, we also prove that every Paley
tournament satisfies Albertson-Collins Conjecture.


title: Exact balanced random imputation for sample survey data

abstract:
  Surveys usually suffer from non-response, which decreases the effective
sample size. Item non-response is typically handled by means of some form of
random imputation if we wish to preserve the distribution of the imputed
variable. This leads to an increased variability due to the imputation
variance, and several approaches have been proposed for reducing this
variability. Balanced imputation consists in selecting residuals at random at
the imputation stage, in such a way that the imputation variance of the
estimated total is eliminated or at least significantly reduced. In this work,
we propose an implementation of balanced random imputation which enables to
fully eliminate the imputation variance. Following the approach in Cardot et
al. (2013), we consider a regularized imputed estimator of a total and of a
distribution function, and we prove that they are consistent under the proposed
imputation method. Some simulation results support our findings.


title: Towards Music Captioning: Generating Music Playlist Descriptions

abstract:
  Descriptions are often provided along with recommendations to help users'
discovery. Recommending automatically generated music playlists (e.g.
personalised playlists) introduces the problem of generating descriptions. In
this paper, we propose a method for generating music playlist descriptions,
which is called as music captioning. In the proposed method, audio content
analysis and natural language processing are adopted to utilise the information
of each track.


title: The Chemistry and Kinematics of Two Molecular Clouds near Sagittarius A*

abstract:
  We have analysed the chemical and kinematic properties of the 20 and 50 km
s$^{-1}$ molecular clouds in the Central Molecular Zone of the Milky Way
Galaxy, as well as those of the molecular ridge bridging these two clouds. Our
work has utilized 37 molecular transitions in the 0.65, 3 and 7-mm wavebands,
from the Mopra and NANTEN2 telescopes. The 0.65-mm NANTEN2 data highlights a
dense condensation of emission within the western part of the 20 km s$^{-1}$
cloud, visible in only four other transitions, which are 3-mm H$^{13}$CN
(1--0), H$^{13}$CO$^{+}$ (1--0), HNC (1--0) and N$_{2}$H$^{+}$ (1--0),
suggesting that the condensation is moderately optically thick and cold. We
find that while the relative chemical abundances between both clouds are alike
in many transitions, suggesting little variation in the chemistry between both
clouds; the 20 km s$^{-1}$, cold cloud is brighter than the 50 km s$^{-1}$
cloud in shock and high density tracers. The spatial distribution of enhanced
emission is widespread in the 20 km s$^{-1}$ cloud, as shown via line ratio
maps. The position velocity diagrams across both clouds indicate that the gas
is well mixed. We show that the molecular ridge is most likely part of the 20
km s$^{-1}$ cloud and that both of them may possibly extend to include the 50
km s$^{-1}$ cloud, as part of one larger cloud. Furthermore, we expect that the
20 km s$^{-1}$ cloud is being tidally sheared as a result of the gravitational
potential from Sgr A*.


title:
Electrically tunable topological superconductivity and Majorana fermions
  in two dimensions

abstract:
  The external controllability of topological superconductors and Majorana
fermions would be important both for fundamental and practical interests. Here
we predict the electric-field control of Majorana fermions in two-dimensional
topological superconductors utilizing a topological insulator thin film
proximity coupled to a conventional $s$-wave superconductor. With ferromagnetic
ordering, the tunable structure inversion asymmetry by vertical electric field
could induce topological quantum phase transition and realize a chiral
topological superconductor state. A zero-energy Majorana bound state appears at
the boundary of an applied electric field spot, which can be observed by
scanning tunneling microscopy. Furthermore, the structure inversion asymmetry
could also enlarge the helical topological superconductor state in the phase
diagram, making the realization of such an exotic state more feasible. The
electrical control of topological phases could further apply to van der Waals
materials such as two-dimensional transition metal dichalcogenides.


title:
Forward Feynman-Kac type representation for semilinear nonconservative
  Partial Differential Equations

abstract:
  We propose a nonlinear forward Feynman-Kac type equation, which represents
the solution of a non-conservative semilinear parabolic Partial Differential
Equations (PDE). We show in particular existence and uniqueness. The solution
of that type of equation can be approached via a weighted particle system.


title: Hard Clusters Maximize Mutual Information

abstract:
  In this paper, we investigate mutual information as a cost function for
clustering, and show in which cases hard, i.e., deterministic, clusters are
optimal. Using convexity properties of mutual information, we show that certain
formulations of the information bottleneck problem are solved by hard clusters.
Similarly, hard clusters are optimal for the information-theoretic
co-clustering problem that deals with simultaneous clustering of two dependent
data sets. If both data sets have to be clustered using the same cluster
assignment, hard clusters are not optimal in general. We point at interesting
and practically relevant special cases of this so-called pairwise clustering
problem, for which we can either prove or have evidence that hard clusters are
optimal. Our results thus show that one can relax the otherwise combinatorial
hard clustering problem to a real-valued optimization problem with the same
global optimum.


title: Black hole solutions in functional extensions of Born-Infeld gravity

abstract:
  We consider electrovacuum black hole spacetimes in classical extensions of
Eddington-inspired Born-Infeld gravity. By rewriting Born-Infeld action as the
square root of the determinant of a matrix $\hat{\Omega}$, we consider the
family of models $f (|\hat{\Omega}|)$, and study black hole solutions for a
power-law family of models labelled by a simple parameter. We show how the
innermost structure of the corresponding black holes is modified as compared to
their General Relativity counterparts, discussing in which cases a wormhole
structure replaces the point-like singularity. We go forward to argue that in
such cases a geodesically complete and thus non-singular spacetime is present,
despite the existence of curvature divergences at the wormhole throat.


title: Wave energy absorption by a floating air bag

abstract:
  A floating air bag, ballasted in water, expands and contracts as it heaves
under wave action. Connecting the bag to a secondary volume via a turbine
transforms the bag into a device capable of generating useful energy from the
waves. Small-scale measurements of the device reveal some interesting
properties, which are successfully predicted numerically. Owing to its
compressibility, the device can have a heave resonance period longer than that
of a rigid device of the same shape and size, without any phase control.
Furthermore, varying the amount of air in the bag is found to change its shape
and hence its dynamic response, while varying the turbine damping or the air
volume ratio changes the dynamic response without changing the shape.


title:
Anomalies in the peer-review system: A case study of the journal of High
  Energy Physics

abstract:
  Peer-review system has long been relied upon for bringing quality research to
the notice of the scientific community and also preventing flawed research from
entering into the literature. The need for the peer-review system has often
been debated as in numerous cases it has failed in its task and in most of
these cases editors and the reviewers were thought to be responsible for not
being able to correctly judge the quality of the work. This raises a question
"Can the peer-review system be improved?" Since editors and reviewers are the
most important pillars of a reviewing system, we in this work, attempt to
address a related question - given the editing/reviewing history of the editors
or re- viewers "can we identify the under-performing ones?", with citations
received by the edited/reviewed papers being used as proxy for quantifying
performance. We term such review- ers and editors as anomalous and we believe
identifying and removing them shall improve the performance of the peer- review
system. Using a massive dataset of Journal of High Energy Physics (JHEP)
consisting of 29k papers submitted between 1997 and 2015 with 95 editors and
4035 reviewers and their review history, we identify several factors which
point to anomalous behavior of referees and editors. In fact the anomalous
editors and reviewers account for 26.8% and 14.5% of the total editors and
reviewers respectively and for most of these anomalous reviewers the
performance degrades alarmingly over time.


title: Current-induced instability of domain walls in cylindrical nanowires

abstract:
  We study the current-driven domain wall (DW) motion in cylindrical nanowires
using micromagnetic simulations by implementing the Landau-Lifshitz-Gilbert
equation with nonlocal spin-transfer torque in a finite difference
micromagnetic package. We find that in the presence of DW Gaussian wave packets
(spin waves) will be generated when the charge current is applied to the system
suddenly. And this effect is excluded when using the local spin-transfer
torque. The existence of spin waves emission indicates that transverse domain
walls can not move arbitrarily fast in cylindrical nanowires although they are
free from the Walker limit. We establish an upper-velocity limit for the DW
motion by analyzing the stability of Gaussian wave packets using the local
spin-transfer torque. Micromagnetic simulations show that the stable region
obtained by using nonlocal spin-transfer torque is smaller than that by using
its local counterpart. This limitation is essential for multiple domain walls
since the instability of Gaussian wave packets will break the structure of
multiple domain walls.


title: On Knotted Spheres in Euclidean $4$-space $ \mathbb{E}^{4}$

abstract:
  In the present study we consider knotted spheres in Euclidean $4$-space $
\mathbb{E}^{4}$. Firstly, we give some basic curvature properties of knotted
spheres in $ \mathbb{E}^{4}$. Further, we obtained some results related with
the conjugate nets and Laplace transforms of these kind of surfaces.


title: Live Prefetching for Mobile Computation Offloading

abstract:
  The conventional designs of mobile computation offloading fetch user-specific
data to the cloud prior to computing, called offline prefetching. However, this
approach can potentially result in excessive fetching of large volumes of data
and cause heavy loads on radio-access networks. To solve this problem, the
novel technique of live prefetching is proposed in this paper that seamlessly
integrates the task-level computation prediction and prefetching within the
cloud-computing process of a large program with numerous tasks. The technique
avoids excessive fetching but retains the feature of leveraging prediction to
reduce the program runtime and mobile transmission energy. By modeling the
tasks in an offloaded program as a stochastic sequence, stochastic optimization
is applied to design fetching policies to minimize mobile energy consumption
under a deadline constraint. The policies enable real-time control of the
prefetched-data sizes of candidates for future tasks. For slow fading, the
optimal policy is derived and shown to have a threshold-based structure,
selecting candidate tasks for prefetching and controlling their prefetched data
based on their likelihoods. The result is extended to design close-to-optimal
prefetching policies to fast fading channels. Compared with fetching without
prediction, live prefetching is shown theoretically to always achieve reduction
on mobile energy consumption.