title: Structure of parabolically induced modules for affine Kac-Moody algebras

abstract:
  The main result of the paper establishes the irreducibility of a large family
of nonzero central charge induced modules over Affine Lie algebras for any non
standard parabolic subalgebra. It generalizes all previously known partial
results and provides a a construction of many new irreducible modules.


title:
Ab initio prediction of stable nanotwin double layers and 4O structure
  in Ni$_{2}$MnGa

abstract:
  The ab initio electronic structure calculations of the Ni$_{2}$MnGa The alloy
indicate that the orthorhombic 4O structure exhibits the lowest energy compared
to all known martensitic structures. The 4O structure is formed by nanotwin
double layers, i.e., oppositely oriented nanotwins consisting of two (101)
lattice planes of nonmodulated martensitic structure. It exhibits the lowest
occupation of density of states at the Fermi level. The total energy 1.98
meV/atom below the energy of nonmodulated martensite is achieved within
structural relaxation by shifting Mn and Ga atoms at the nanotwin boundaries.
The same atomic shift can also be found in other martensitic nanotwinned or
modulated structures such as 10M and 14M, which indicates the importance of the
nanotwin double layer for the stability of these structures. Our discovery
shows that the nanotwinning or modulation is a natural property of
low-temperature martensitic phases in Ni-Mn-Ga alloys.


title: Fluctuations of Functions of Wigner Matrices

abstract:
  We show that matrix elements of functions of $N\times N$ Wigner matrices
fluctuate on a scale of order $N^{-1/2}$ and we identify the limiting
fluctuation. Our result holds for any function $f$ of the matrix that has
bounded variation and thus considerably relaxes the regularity requirement
imposed in [7,11].


title:
Radiation of non-relativistic particle on a conducting sphere and a
  string of spheres

abstract:
  The radiation arising under uniform motion of non-relativistic charged
particle by (or through) perfectly conducting sphere is considered. The
rigorous results are obtained using the method of images known from
electrostatics.


title: Deep image mining for diabetic retinopathy screening

abstract:
  Deep learning is quickly becoming the leading methodology for medical image
analysis. Given a large medical archive, where each image is associated with a
diagnosis, efficient pathology detectors or classifiers can be trained with
virtually no expert knowledge about the target pathologies. However, deep
learning algorithms, including the popular ConvNets, are black boxes: little is
known about the local patterns analyzed by ConvNets to make a decision at the
image level. A solution is proposed in this paper to create heatmaps showing
which pixels in images play a role in the image-level predictions. In other
words, a ConvNet trained for image-level classification can be used to detect
lesions as well. A generalization of the backpropagation method is proposed in
order to train ConvNets that produce high-quality heatmaps. The proposed
solution is applied to diabetic retinopathy (DR) screening in a dataset of
almost 90,000 fundus photographs from the 2015 Kaggle Diabetic Retinopathy
competition and a private dataset of almost 110,000 photographs (e-ophtha). For
the task of detecting referable DR, very good detection performance was
achieved: $A_z = 0.954$ in Kaggle's dataset and $A_z = 0.949$ in e-ophtha.
Performance was also evaluated at the image level and at the lesion level in
the DiaretDB1 dataset, where four types of lesions are manually segmented:
microaneurysms, hemorrhages, exudates and cotton-wool spots. The proposed
detector outperforms recent algorithms trained to detect those lesions
specifically, as well as competing heatmap generation algorithms for ConvNets.
This detector is part of the Messidor system for mobile eye pathology
screening. Because it does not rely on expert knowledge or manual segmentation
for detecting relevant patterns, the proposed solution is a promising image
mining tool, which has the potential to discover new biomarkers in images.


title: Higher Commutator Theory for Congruence Modular Varieties

abstract:
  We develop the basic properties of the higher commutator for congruence
modular varieties.


title:
Differential-free characterisation of smooth mappings with controlled
  growth

abstract:
  In this paper we give some generalizations and improvements of the Pavlovi\'c
result on the Holland-Walsh type characterization of the Bloch space of
continuously differentiable (smooth) functions in the unit ball in
$\mathbf{R}^m$.


title:
Reinforcement Learning in Conflicting Environments for Autonomous
  Vehicles

abstract:
  In this work, we investigate the application of Reinforcement Learning to two
well known decision dilemmas, namely Newcomb's Problem and Prisoner's Dilemma.
These problems are exemplary for dilemmas that autonomous agents are faced with
when interacting with humans. Furthermore, we argue that a Newcomb-like
formulation is more adequate in the human-machine interaction case and
demonstrate empirically that the unmodified Reinforcement Learning algorithms
end up with the well known maximum expected utility solution.


title: STEPS: Predicting place attributes via spatio-temporal analysis

abstract:
  In recent years, a vast amount of research has been conducted on learning
people's interests from their actions. Yet their collective actions also allow
us to learn something about the world, in particular, infer attributes of
places people visit or interact with. Imagine classifying whether a hotel has a
gym or a swimming pool, or whether a restaurant has a romantic atmosphere
without ever asking its patrons. Algorithms we present can do just that.
  Many web applications rely on knowing attributes of places, for instance,
whether a particular restaurant has WiFi or offers outdoor seating. Such data
can be used to support a range of user experiences, from explicit query-driven
search to personalized place recommendations. However, obtaining these
attributes is generally difficult, with existing approaches relying on
crowdsourcing or parsing online reviews, both of which are noisy, biased, and
have limited coverage. Here we present a novel approach to classifying place
attributes, which learns from patrons' visit patterns based on anonymous
observational data.
  Our method, STEPS, learns from aggregated sequences of place visits. For
example, if many people visit the restaurant on a Saturday evening, coming from
a luxury hotel or theater, and stay for a long time, then this restaurant is
more likely to have a romantic atmosphere. On the other hand, if most people
visit the restaurant on weekdays, coming from work or a grocery store, then the
restaurant is less likely to be romantic. We show that such transition features
are highly predictive of place attributes. In an extensive empirical
evaluation, STEPS nearly doubled the coverage of a state of the art approach
thanks to learning from observational location data, which allowed our method
to reason about many more places.


title: Automatic Identification of Sarcasm Target: An Introductory Approach

abstract:
  Past work in computational sarcasm deals primarily with sarcasm detection. In
this paper, we introduce a novel, related problem: sarcasm target
identification i.e., extracting the target of ridicule in a sarcastic
sentence). We present an introductory approach for sarcasm target
identification. Our approach employs two types of extractors: one based on
rules, and another consisting of a statistical classifier. To compare our
approach, we use two baselines: a na\"ive baseline and another baseline based
on work in sentiment target identification. We perform our experiments on book
snippets and tweets, and show that our hybrid approach performs better than the
two baselines and also, in comparison with using the two extractors
individually. Our introductory approach establishes the viability of sarcasm
target identification, and will serve as a baseline for future work.


title: Bounds in Cohen's idempotent theorem

abstract:
  We show that if $G$ is a finite Abelian group and $f$ is an integer-valued
map on $G$ with algebra norm at most $M$ then there is some $L <
\exp(M^{4+o(1)})$, cosets of (possibly different) subgroups $W_1,...,W_L$, and
$s_1,...,s_L \in \{-1,1\}$ such that $f=\sum_i{s_i1_{W_i}}$.


title:
Equivalence between contextuality and negativity of the Wigner function
  for qudits

abstract:
  Contextuality and negativity of the Wigner function are two notions of
non-classicality for quantum systems. Howard, Wallman, Veitch and Emerson
proved recently that these two notions coincide for qudits in odd prime
dimension. This equivalence is particularly important since it promotes
contextuality as a ressource that magic states must possess in order to allow
for a quantum speed-up. We propose a simple proof of the equivalence between
contextuality and negativity of the Wigner function based on character theory.
This simplified approach allows us to generalize this equivalence to multiple
qudits and to any qudit system of odd local dimension.


title:
Inferring parameters of prey switching in a plankton 1 predator--2 prey
  system with a linear preference tradeoff

abstract:
  We construct two ordinary-differential-equation models of a predator feeding
adaptively on two prey types, and we evaluate the models' ability to fit data
on freshwater plankton. We model the predator's switch from one prey to the
other in two different ways: (1) smooth switching using a hyperbolic tangent
function; and (2) by incorporating a parameter that changes abruptly across the
switching boundary as a system variable that is coupled to the population
dynamics. We conduct linear stability analyses, use approximate Bayesian
computation (ABC) combined with a population Monte Carlo (PMC) method to fit
model parameters, and compare model predictions quantitatively to data for
ciliate predators and their two algal prey groups collected from Lake Constance
on the German--Swiss--Austrian border. We show that the two models fit the data
well when the smooth transition is steep, supporting the simplifying assumption
of a discontinuous prey switching behavior for this scenario. We thus conclude
that prey switching is a possible mechanistic explanation for the observed
ciliate--algae dynamics in Lake Constance in spring, but that these data cannot
distinguish between the details of prey switching that are encoded in these
different models.


title:
Observation of Upsilon(1S) pair production in proton-proton collisions
  at sqrt(s) = 8 TeV

abstract:
  Pair production of Upsilon(1S) mesons is observed at the LHC in proton-proton
collisions at sqrt(s) = 8 TeV by the CMS experiment in a data sample
corresponding to an integrated luminosity of 20.7 inverse femtobarns. Both
Upsilon(1S) candidates are fully reconstructed via their decays to mu+ mu-. The
fiducial acceptance region is defined by an absolute Upsilon(1S) rapidity
smaller than 2.0. The fiducial cross section for the production of Upsilon(1S)
pairs, assuming that both mesons decay isotropically, is measured to be 68.8
+/- 12.7 (stat) +/- 7.4 (syst) +/- 2.8 (B) pb, where the third uncertainty
comes from the uncertainty in the branching fraction of Upsilon(1S) decays to
mu+ mu-. Assuming instead that the Upsilon(1S) mesons are produced with
different polarizations leads to variations in the measured cross section in
the range from -38% to +36%.


title: A statistical approach to covering lemmas

abstract:
  We discuss a statistical variant of Ruzsa's covering lemma and use it to show
that if G is an Abelian group of bounded exponent and A in G has |A+A| < K|A|
then the subgroup generated by A has size at most exp(O(K log^22K))|A|, where
the constant in the big-O depends on the exponent of the group only.


title: Analysis of minimal representations of SL(n,R)

abstract:
  Some minimal representations of SL(n,R) can be realized on a Hilbert space of
holomorphic functions. This is the analogue of the Brylinski-Kostant model.
They can also be realized on a Hilbert space of homogeneous functions on
${\bboard R}^n$. This is the analogue of the Kobayashi-Orsted model. We will
describe the two realizations and a transformation which maps one model to the
other. It can be seen as an analogue of the classical Bargmann transform.


title:
A boundary integral method for the general conjugation problem in
  multiply connected circle domains

abstract:
  We present a boundary integral method for solving a certain class of
Riemann-Hilbert problems known as the general conjugation problem. The method
is based on a uniquely solvable boundary integral equation with the generalized
Neumann kernel. We present also an alternative proof for the existence and
uniqueness of the solution of the general conjugation problem.


title: Excess area dependent scaling behavior of nano-sized membrane tethers

abstract:
  Thermal fluctuations in cell membranes manifest as an excess area (${\cal
A}_{\rm ex}$) which governs a multitude of physical process at the sub-micron
scale. We present a theoretical framework, based on an in silico tether pulling
method, which may be used to reliably estimate ${\cal A}_{\rm ex}$ in live
cells. The tether forces estimated from our simulations compare well with our
experimental measurements for tethers extracted from ruptured GUVs and HeLa
cells. We demonstrate the significance and validity of our method by showing
that all our calculations along with experiments of tether extraction in 15
different cell types collapse onto two unified scaling relationships mapping
tether force, tether radius, bending stiffness $\kappa$, and membrane tension
$\sigma$. We show that $R_{\rm bead}$, the size of the wetting region, is an
important determinant of the radius of the extracted tether, which is equal to
$\xi=\sqrt{\kappa/2\sigma}$ (a characteristic length scale of the membrane) for
$R_{\rm bead}<\xi$, and is equal to $R_{\rm bead}$ for $R_{\rm bead}>\xi$. We
also find that the estimated excess area follows a linear scaling behavior that
only depends on the true value of ${\cal A}_{\rm ex}$ for the membrane, based
on which we propose a self-consistent technique to estimate the range of excess
membrane areas in a cell.

categories: physics.bio-ph cond-mat.mes-hall cond-mat.soft cond-mat.stat-mech physics.comp-ph


title: Local Maxima and Improved Exact Algorithm for MAX-2-SAT

abstract:
  Given a MAX-2-SAT instance, we define a local maximum to be an assignment
such that changing any single variable reduces the number of satisfied clauses.
We consider the question of the number of local maxima that an instance of
MAX-2-SAT can have. We give upper bounds in both the sparse and nonsparse case,
where the sparse case means that there is a bound $d$ on the average number of
clauses involving any given variable. The bounds in the nonsparse case are
tight up to polylogarithmic factors, while in the sparse case the bounds are
tight up to a multiplicative factor in $d$ for large $d$. Additionally, we
generalize to the question of assignments which are maxima up to changing $k>
1$ variables simultaneously; in this case, we give explicit constructions with
large (in a sense explained below) numbers of such maxima in the sparse case.
The basic idea of the upper bound proof is to consider a random assignment to
some subset of the variables and determine the probability that some fraction
of the remaining variables can be fixed without considering interactions
between them. The bounded results hold in the case of weighted MAX-2-SAT as
well. Using this technique and combining with ideas from Ref. 6, we find an
algorithm for weighted MAX-2-SAT which is faster for large $d$ than previous
algorithms which use polynomial space; this algorithm does require an
additional bounds on maximum weights and degree.


title: General Central Limit Theorems for Associated Sequences

abstract:
  In this paper, we provide general central limit theorems (CLT's) for
associated random variables (rv's) following the approaches used by Newman
(1980) and Olivera et al.(2012). Given some assumptions, a
Lyapounov-Feller-Levy type theorem is stated. We next specify different
particular CLT versions of associated sequences based on moment conditions. A
comparison study with available CTL's is performed. As a by-product, we
complete an important available theorem where an assumption was missing.


title: Depinning asymptotics in ergodic media

abstract:
  We study speeds of fronts in bistable, spatially inhomogeneous media at
parameter regimes where speeds approach zero. We provide a set of conceptual
assumptions under which we can prove power-law asymptotics for the speed, with
exponent depending a local dimension of the ergodic measure near extremal
values. We also show that our conceptual assumptions are satisfied in a context
of weak inhomogeneity of the medium and almost balanced kinetics, and compare
asymptotics with numerical simulations.


title:
Surface tension and a self-consistent theory of soft composite solids
  with elastic inclusions

abstract:
  The importance of surface tension effects is being recognized in the context
of soft composite solids, where it is found to significantly affect the
mechanical properties, such as the elastic response to an external stress. It
has recently been discovered that Eshelby's inclusion theory breaks down when
the inclusion size approaches the elastocapillary length $L\equiv\gamma/E$,
where $\gamma$ is the inclusion/host surface tension and $E$ is the host
Young's modulus. Extending our recent results for liquid inclusions, here we
model the elastic behavior of a non-dilute distribution of isotropic elastic
spherical inclusions in a soft isotropic elastic matrix, subject to a
prescribed infinitesimal far-field loading. Within our framework, the composite
stiffness is uniquely determined by the elastocapillary length $L$, the
spherical inclusion radius $R$, and the stiffness contrast parameter ${C}$,
which is the ratio of the inclusion to the matrix stiffness. We compare the
results with those from the case of liquid inclusions, and we derive an
analytical expression for elastic cloaking of the composite by the inclusions.
Remarkably, we find that the composite stiffness is influenced significantly by
surface tension even for inclusions two orders of magnitude more stiff than the
host matrix. Finally, we show how to simultaneously determine the surface
tension and the inclusion stiffness using two independent constraints provided
by global and local measurements.


title: Independent Component Analysis by Entropy Maximization with Kernels

abstract:
  Independent component analysis (ICA) is the most popular method for blind
source separation (BSS) with a diverse set of applications, such as biomedical
signal processing, video and image analysis, and communications. Maximum
likelihood (ML), an optimal theoretical framework for ICA, requires knowledge
of the true underlying probability density function (PDF) of the latent
sources, which, in many applications, is unknown. ICA algorithms cast in the ML
framework often deviate from its theoretical optimality properties due to poor
estimation of the source PDF. Therefore, accurate estimation of source PDFs is
critical in order to avoid model mismatch and poor ICA performance. In this
paper, we propose a new and efficient ICA algorithm based on entropy
maximization with kernels, (ICA-EMK), which uses both global and local
measuring functions as constraints to dynamically estimate the PDF of the
sources with reasonable complexity. In addition, the new algorithm performs
optimization with respect to each of the cost function gradient directions
separately, enabling parallel implementations on multi-core computers. We
demonstrate the superior performance of ICA-EMK over competing ICA algorithms
using simulated as well as real-world data.


title: Broken sublattice symmetry states in Bernal stacked multilayer graphene

abstract:
  We analyze the ordered phases of Bernal stacked multilayer graphene in the
presence of interaction induced band gaps due to sublattice symmetry breaking
potentials, whose solutions can be analyzed in terms of light-mass and
heavy-mass pseudospin doublets which have the same Chern numbers but opposite
charge polarization directions. The application of a perpendicular external
electric field reveals an effective Hund's rule for the ordering of the
sublattice pseudospin doublets in a tetralayer, while a similar but more
complex phase diagram develops with increasing layer number.


title: Ultrafast pulse generation in a mode-locked Erbium chip waveguide laser

abstract:
  We report mode-locked ~1550 nm output of transform-limited ~180 fs pulses
from a large mode-area (diameter ~ 50 {\mu}m) guided-wave erbium
fluorozirconate glass laser. The passively mode-locked oscillator generates
pulses with 25 nm bandwidth at 156 MHz repetition rate and peak-power of 260 W.
Scalability to higher repetition rate is demonstrated by transform-limited 410
fs pulse output at 1.3 GHz. To understand the origins of the broad spectral
output, the laser cavity is simulated by using a numerical solution to the
Ginzburg-Landau equation. This paper reports the widest bandwidth and shortest
pulses achieved from an ultra-fast laser inscribed waveguide laser.


title:
Efficient quantum circuits for continuous-time quantum walks on
  composite graphs

abstract:
  In this paper, we investigate the simulation of continuous-time quantum walks
on specific classes of graphs, for which it is possible to fast-forward the
time-evolution operator to achieve constant-time simulation complexity and to
perform the simulation exactly, while maintaining $\mbox{poly}(\mbox{log}(n))$
efficiency. In particular, we discuss two classes of composite graphs,
commuting graphs and Cartesian product of graphs, that contain classes of
graphs which can be simulated in this fashion. This allows us to identify new
families of graphs that we can efficiently simulate in a quantum circuit
framework, providing practical and explicit means to explore quantum-walk based
algorithms in laboratories.


title: Fast and Reliable Parameter Estimation from Nonlinear Observations

abstract:
  In this paper we study the problem of recovering a structured but unknown
parameter ${\bf{\theta}}^*$ from $n$ nonlinear observations of the form
$y_i=f(\langle {\bf{x}}_i,{\bf{\theta}}^*\rangle)$ for $i=1,2,\ldots,n$. We
develop a framework for characterizing time-data tradeoffs for a variety of
parameter estimation algorithms when the nonlinear function $f$ is unknown.
This framework includes many popular heuristics such as projected/proximal
gradient descent and stochastic schemes. For example, we show that a projected
gradient descent scheme converges at a linear rate to a reliable solution with
a near minimal number of samples. We provide a sharp characterization of the
convergence rate of such algorithms as a function of sample size, amount of
a-prior knowledge available about the parameter and a measure of the
nonlinearity of the function $f$. These results provide a precise understanding
of the various tradeoffs involved between statistical and computational
resources as well as a-prior side information available for such nonlinear
parameter estimation problems.


title:
Symplectic Geometric Algorithm for Quaternion Kinematical Differential
  Equation

abstract:
  Solving quaternion kinematical differential equations is one of the most
significant problems in the automation, navigation, aerospace and aeronautics
literatures. Most existing approaches for this problem neither preserve the
norm of quaternions nor avoid errors accumulated in the sense of long term
time. We present symplectic geometric algorithms to deal with the quaternion
kinematical differential equation by modeling its time-invariant and
time-varying versions with Hamiltonian systems by adopting a three-step
strategy. Firstly, a generalized Euler's formula for the autonomous quaternion
kinematical differential equation are proved and used to construct symplectic
single-step transition operators via the centered implicit Euler scheme for
autonomous Hamiltonian system. Secondly, the symplecitiy, orthogonality and
invertibility of the symplectic transition operators are proved rigorously.
Finally, the main results obtained are generalized to design symplectic
geometric algorithm for the time-varying quaternion kinematical differential
equation which is a non-autonomous and nonlinear Hamiltonian system
essentially. Our novel algorithms have simple algorithmic structures and low
time complexity of computation, which are easy to be implemented with real-time
techniques. The correctness and efficiencies of the proposed algorithms are
verified and validated via numerical simulations.


title: Tsallis thermostatics as a statistical physics of random chains

abstract:
  In this paper we point out that the generalized statistics of
Tsallis-Havrda-Charv\'at can be conveniently used as a conceptual framework for
statistical treatment of random chains. In particular, we use the path-integral
approach to show that the ensuing partition function can be identified with the
partition function of a fluctuating oriented random loop of arbitrary length
and shape in a background scalar potential. To put some meat on the bare bones,
we illustrate this with two statistical systems; Schultz-Zimm polymer and
relativistic particle. Further salient issues such as the $PSL(2;R)$
transformation properties of Tsallis' inverse-temperature parameter and a
grandcanonical ensemble of fluctuating random loops related to the
Tsallis-Havrda-Charv\'at statistics are also briefly discussed.

categories: cond-mat.stat-mech math-ph math.MP quant-ph


title: Exact solution of a generalized two-sites Bose-Hubbard model

abstract:
  I introduce a new parametrization of a bosonic Lax operator for the algebraic
Bethe ansatz method with the $gl(2)$-invariant $R$-matrix and use it to present
the exact solution of a generalized two-sites Bose-Hubbard model with
asymmetric tunnelling. In the no interaction limit I show that the Bethe ansatz
equations can be written as a $S^{N-1}$ sphere, where $N$ is the total number
of atoms in the condensate.

categories: cond-mat.quant-gas hep-th math-ph math.MP nlin.SI quant-ph


title: Nonlinear $E$-mode clustering in Lagrangian space

abstract:
  We study the nonlinear $E$-mode clustering in Lagrangian space by using large
scale structure $N$-body simulations and use the displacement field information
in Lagrangian space to recover the primordial linear density field. We find
that, compared to Eulerian nonlinear density fields, the $E$-mode displacement
fields in Lagrangian space improves the cross-correlation scale $k$ with
initial density field by a factor of 6-7, containing two orders of magnitude
more primordial information. This illustrates ability of potential density
reconstruction algorithms, to improve the baryonic acoustic oscillation
measurements from current and future large scale structure surveys.


title:
Unusual UUDD magnetic chain structure of the spin-1/2 tetragonally
  distorted spinel GeCu2O4

abstract:
  GeCu2O4 exhibits a tetragonal spinel structure due to the strong Jahn-Teller
distortion associated with Cu2+ ions. We show that its magnetic structure can
be described as slabs composed of a pair of layers with orthogonally oriented
spin 1/2 Cu chains in the basal ab plane. The spins between the two layers
within a slab are collinearly aligned while the spin directions of neighboring
slabs are perpendicular to each other. Interestingly, we find that spins along
each chain form an unusual up-up-down-down (UUDD) pattern, suggesting a
non-negligible nearest-neighbor biquadratic exchange interaction in the
effective classical spin Hamiltonian. We hypothesize that spin-orbit coupling
and orbital mixing of Cu2+ ions in this system is non-negligible, which calls
for future calculations using perturbation theory with extended Hilbert (spin
and orbital) space and calculations based on density functional theory
including spin-orbit coupling and looking at the global stability of the UUDD
state.


title: Thermal cascaded lattice Boltzmann method

abstract:
  In this paper, a thermal cascaded lattice Boltzmann method (TCLBM) is
developed in combination with the double-distribution-function (DDF) approach.
A density distribution function relaxed by the cascaded scheme is employed to
solve the flow field, and a total energy distribution function relaxed by the
BGK scheme is used to solve temperature field, where two distribution functions
are coupled naturally. The forcing terms are incorporated by means of central
moments, which is consistent with the previous force scheme [Premnath \emph{et
al.}, Phys. Rev. E \textbf{80}, 036702 (2009)] but the derivation is more
intelligible and the evolution process is simpler. In the method, the viscous
heat dissipation and compression work are taken into account, the Prandtl
number and specific-heat ratio are adjustable, the external force is considered
directly without the Boussinesq assumption, and the low-Mach number
compressible flows can also be simulated. The forcing scheme is tested by
simulating a steady Taylor-Green flow, and the new TCLBM is then tested by
numerical experiments of the thermal Couette flow, low-Mach number shock tube
problem, and Rayleigh-B\'{e}nard convection. The simulation results agree well
with the analytical solutions and/or results given by previous researchers.


title:
A Simple Picosecond Pulse Generator Based on a Pair of Step Recovery
  Diodes

abstract:
  A picosecond pulse generator based on a pair of step recovery diodes (SRD),
leveraging the transient response of the SRD PN junction and controlling the
pulse width by a resistor, is proposed. We first explain the operation
principle of the device, decomposing the pulse generation into different
phases, and then demonstrate an experimental prototype with two different
resistance, and hence pulse width, values.


title: Online Classification with Complex Metrics

abstract:
  We present a framework and analysis of consistent binary classification for
complex and non-decomposable performance metrics such as the F-measure and the
Jaccard measure. The proposed framework is general, as it applies to both batch
and online learning, and to both linear and non-linear models. Our work follows
recent results showing that the Bayes optimal classifier for many complex
metrics is given by a thresholding of the conditional probability of the
positive class. This manuscript extends this thresholding characterization --
showing that the utility is strictly locally quasi-concave with respect to the
threshold for a wide range of models and performance metrics. This, in turn,
motivates simple normalized gradient ascent updates for threshold estimation.
We present a finite-sample regret analysis for the resulting procedure. In
particular, the risk for the batch case converges to the Bayes risk at the same
rate as that of the underlying conditional probability estimation, and the risk
of proposed online algorithm converges at a rate that depends on the
conditional probability estimation risk. For instance, in the special case
where the conditional probability model is logistic regression, our procedure
achieves $O(\frac{1}{\sqrt{n}})$ sample complexity, both for batch and online
training. Empirical evaluation shows that the proposed algorithms out-perform
alternatives in practice, with comparable or better prediction performance and
reduced run time for various metrics and datasets.


title:
Role of a triangle singularity in the $\gamma p\rightarrow K^+
  \Lambda(1405)$ reaction

abstract:
  We show the effects of a triangle singularity mechanism for the $\gamma p \to
K^+\Lambda(1405)$ reaction. The mechanism has a $N^*$ resonance around 2030
MeV, which decays into $K^* \Sigma$. The $K^*$ decays to $K^+ \pi$, and the
$\pi \Sigma$ merge to form the $\Lambda(1405)$. This mechanism produces a peak
around $\sqrt{s} = 2110$ MeV, and has its largest contribution around
cos$\theta=0$. The addition of this mechanism to other conventional ones, leads
to a good reproduction of ${\rm d}\sigma/{\rm dcos}\theta$ and the integrated
cross section around this energy, providing a solution to a problem encountered
in previous theoretical models.


title: Verified Parallel String Matching in Haskell

abstract:
  In this paper, we prove correctness of parallelizing a string matcher using
Haskell as a theorem prover. We use refinement types to specify correctness
properties, Haskell terms to express proofs and Liquid Haskell to check
correctness of proofs. First, we specify and prove that a class of monoid
morphisms can be parallelized via parallel monoid concatenation. Then, we
encode string matching as a morphism to get a provably correct parallel
transformation. Our 1839LoC prototype proof shows that Liquid Haskell can be
used as a fully expressive theorem prover on realistic Haskell implementations.


title:
Cross Device Matching for Online Advertising with Neural Feature
  Ensembles : First Place Solution at CIKM Cup 2016

abstract:
  We describe the 1st place winning approach for the CIKM Cup 2016 Challenge.
In this paper, we provide an approach to reasonably identify same users across
multiple devices based on browsing logs. Our approach regards a candidate
ranking problem as pairwise classification and utilizes an unsupervised neural
feature ensemble approach to learn latent features of users. Combined with
traditional hand crafted features, each user pair feature is fed into a
supervised classifier in order to perform pairwise classification. Lastly, we
propose supervised and unsupervised inference techniques.


title:
Iterative coupling of flow, geomechanics and adaptive phase-field
  fracture including level-set crack width approaches

abstract:
  In this work, we present numerical studies of fixed-stress iterative coupling
for solving flow and geomechanics with propagating fractures in a porous
medium. Specifically, fracture propagations are described by employing a
phase-field approach. The extension to fixed-stress splitting to propagating
phase-field fractures and systematic investigation of its properties are
important enhancements to existing studies. Moreover, we provide an accurate
computation of the fracture opening using level-set approaches and a subsequent
finite element interpolation of the width. The latter enters as fracture
permeability into the pressure diffraction problem which is crucial for fluid
filled fractures. Our developments are substantiated with several numerical
tests that include comparisons of computational cost for iterative coupling and
nonlinear and linear iterations as well as convergence studies in space and
time.


title:
Adaptive enriched Galerkin methods for miscible displacement problems
  with entropy residual stabilization

abstract:
  We present a novel approach to the simulation of miscible displacement by
employing adaptive enriched Galerkin finite element methods (EG) coupled with
entropy residual stabilization for transport. In particular, numerical
simulations of viscous fingering instabilities in heterogeneous porous media
and Hele-Shaw cells are illustrated. EG is formulated by enriching the
conforming continuous Galerkin finite element method (CG) with piecewise
constant functions. The method provides locally and globally conservative
fluxes, which is crucial for coupled flow and transport problems. Moreover, EG
has fewer degrees of freedom in comparison with discontinuous Galerkin (DG) and
an efficient flow solver has been derived which allows for higher order
schemes. Dynamic adaptive mesh refinement is applied in order to save
computational cost for large-scale three dimensional applications. In addition,
entropy residual based stabilization for high order EG transport systems
prevents any spurious oscillations. Numerical tests are presented to show the
capabilities of EG applied to flow and transport.


title: Tangle Floer homology and cobordisms between tangles

abstract:
  We introduce a generalization of oriented tangles, which are still called
tangles, so that they are in one-to-one correspondence with the sutured
manifolds. We define cobordisms between sutured manifolds (tangles) by
generalizing cobordisms between oriented tangles. For every commutative algebra
A over Z/2Z, we define A-Tangles to be the category consisting of A-tangles,
which are balanced tangles with A-colorings of the tangle strands and fixed
SpinC structures, and A-cobordisms as morphisms. An A-cobordism is a cobordism
with a compatible A-coloring and an affine set of SpinC structures. Associated
with every A-module M we construct a functor $HF^M$ from A-Tangles to
A-Modules, called the tangle Floer homology functor, where A-Modules denotes
the the category of A-modules and A-homomorphisms between them. Moreover, for
any A-tangle T the A-module $HF^M(T)$ is the extension of sutured Floer
homology defined in an earlier work of the authors. In particular, this
construction generalizes the 4-manifold invariants of Ozsvath and Szabo.
Moreover, applying the above machinery to decorated cobordisms between links,
we get functorial maps on link Floer homology.


title: Analysis of Count Data by Transmuted Geometric Distribution

abstract:
  Transmuted geometric distribution (TGD) was recently introduced and
investigated by Chakraborty and Bhati (2016). This is a flexible extension of
geometric distribution having an additional parameter that determines its zero
inflation as well as the tail length. In the present article we further study
this distribution for some of its reliability, stochastic ordering and
parameter estimation properties. In parameter estimation among others we
discuss an EM algorithm and the performance of estimators is evaluated through
extensive simulation. For assessing the statistical significance of additional
parameter, Likelihood ratio test, the Rao's score tests and the Wald's test are
developed and its empirical power via simulation were compared. We have
demonstrate two applications of (TGD) in modeling real life count data.


title:
An Alternative Method to Implement Contact Angle Boundary Condition on
  Immersed Surfaces for Phase-Field Simulations

abstract:
  In this paper, we propose an alternative approach to implement the contact
angle boundary condition on immersed surfaces for phase-field simulations of
two-phase flows using the Cahn-Hilliard equation on a Cartesian mesh. This
simple and effective method was inspired by previous works on the geometric
formulation of the wetting boundary condition. In two dimensions, by making
full use of the hyperbolic tangent profile of the order parameter, we were able
to obtain its unknown value at a ghost point from the information at only one
point in the fluid. This is in contrast with previous approaches using
interpolations involving several points. The special feature allows this method
to be easily implemented on immersed surfaces (including curved ones) that cut
through the grid lines. It is verified through the study of two examples: (1)
the shape of a drop on a circular cylinder with different contact angles; (2)
the spreading of a drop on an embedded inclined wall with a given contact
angle.


title:
On the hyperplane conjecture for periods of Calabi-Yau hypersurfaces in
  $\mathbb P^n$

abstract:
  In [HLY1], Hosono, Lian, and Yau posed a conjecture characterizing the set of
solutions to certain Gelfand-Kapranov-Zelevinsky hypergeometric equations which
are realized as periods of Calabi-Yau hypersurfaces in a Gorenstein Fano toric
variety $X$. We prove this conjecture in the case where $X$ is a complex
projective space.


title:
On Unifying Multi-View Self-Representations for Clustering by Tensor
  Multi-Rank Minimization

abstract:
  In this paper, we address the multi-view subspace clustering problem. Our
method utilizes the circulant algebra for tensor, which is constructed by
stacking the subspace representation matrices of different views and then
rotating, to capture the low rank tensor subspace so that the refinement of the
view-specific subspaces can be achieved, as well as the high order correlations
underlying multi-view data can be explored.} By introducing a recently proposed
tensor factorization, namely tensor-Singular Value Decomposition (t-SVD)
\cite{kilmer13}, we can impose a new type of low-rank tensor constraint on the
rotated tensor to capture the complementary information from multiple views.
Different from traditional unfolding based tensor norm, this low-rank tensor
constraint has optimality properties similar to that of matrix rank derived
from SVD, so the complementary information among views can be explored more
efficiently and thoroughly. The established model, called t-SVD based
Multi-view Subspace Clustering (t-SVD-MSC), falls into the applicable scope of
augmented Lagrangian method, and its minimization problem can be efficiently
solved with theoretical convergence guarantee and relatively low computational
complexity. Extensive experimental testing on eight challenging image dataset
shows that the proposed method has achieved highly competent objective
performance compared to several state-of-the-art multi-view clustering methods.


title:
The quadratic regulator problem and the Riccati equation for a process
  governed by a linear Volterra integrodifferential equations

abstract:
  In this paper we study the quadratic regulator problem for a process governed
by a Volterra integral equation in ${\mathbb R}^n$. Our main goal is the proof
that it is possible to associate a Riccati differential equation to this
quadratic control problem, which leads to the feedback form of the optimal
control. This is in contrast with previous papers on the subject, which confine
themselves to study the Fredholm integral equation which is solved by the
optimal control.


title:
Linear optical quantum metrology with single photons --- Experimental
  errors, resource counting, and quantum Cram\'er-Rao bounds

abstract:
  Quantum number-path entanglement is a resource for super-sensitive quantum
metrology and in particular provides for sub-shotnoise or even
Heisenberg-limited sensitivity. However, such number-path entanglement has
thought to have been resource intensive to create in the first place ---
typically requiring either very strong nonlinearities, or nondeterministic
preparation schemes with feed-forward, which are difficult to implement.
Recently in [Phys. Rev. Lett. 114, 170802 (2015)] we showed that number-path
entanglement from a BosonSampling inspired interferometer can be used to beat
the shot-noise limit. In this manuscript we compare and contrast different
interferometric schemes, discuss resource counting, calculate exact quantum
Cram\'er-Rao bounds, and study details of experimental errors.


title: Developing and Assessing MATLAB Exercises for Active Concept Learning

abstract:
  New technologies, such as MOOCs, provide innovative methods to tackle new
challenges in teaching and learning, such as globalization and changing
contemporary culture and to remove the limits of conventional classrooms.
However, they also bring challenges in course delivery and assessment, due to
factors such as less direct student-instructor interaction. These challenges
are especially severe in engineering education, which relies heavily on
experiential learning, such as computer simulations and laboratory exercises,
to assist students in understanding concepts. As a result, effective design of
experiential learning components is extremely critical for engineering MOOCs.
In this paper, we will share our experience gained through developing and
offering a MOOC on communication systems, with special focus on the development
and assessment of MATLAB exercises for active concept learning. Our approach
introduced students to concepts using learning components commonly provided by
many MOOC platforms (e.g., online lectures and quizzes), and augmented the
student experience with MATLAB based computer simulations and exercises to
enable more concrete and detailed understanding of the material. We describe
here a systematic approach to MATLAB problem design and assessment, based on
our experience with the MATLAB server provided by MathWorks and integrated with
the edX MOOC platform. We discuss the effectiveness of the instructional
methods as evaluated through students' learning performance. We analyze the
impact of the course design tools from both the instructor and the student
perspective.


title: Quantum Trajectories: Dirac, Moyal and Bohm

abstract:
  We recall Dirac's early proposals to develop a description of quantum
phenomena in terms of a non-commutative algebra in which he suggested a way to
construct what he called `quantum trajectories'. Generalising these ideas, we
show how they are related to weak values and explore their use in the
experimental construction of quantum trajectories. We discuss covering spaces
which play an essential role in accounting for the `wave' properties of quantum
particles. We briefly point out how new mathematical techniques take us beyond
Hilbert space and into a deeper structure which connects with the algebras
originally introduced by Born, Heisenberg and Jordan. This enables us to bring
out the geometric aspects of quantum phenomena.


title: Asymptotic of Non-Crossings probability of Additive Wiener Fields

abstract:
  Let $W_i=\{W_i(t_i), t_i\in \R_+\}, i=1,2,\ldots,d$ are independent Wiener
processes. $W=\{W(\mathbf{t}),t\in \R_+^d\}$ be the additive Wiener field
define as the sum of $W_i$. For any trend $f$ in $\kHC$ (the reproducing kernel
Hilbert Space of $W$), we derive upper and lower bounds for the boundary
non-crossing probability $$P_f=P\{\sum_{i=1}^{d}W_i(t_i) +f(\mathbf{t})\leq
u(\mathbf{t}), \mathbf{t}\in\R_+^d\},$$ where $u: \R_+^d\rightarrow \R_+$ is a
measurable function. Furthermore, for large trend functions $\gamma f>0$, we
show that the asymptotically relation $\ln P_{\gamma f}\sim \ln P_{\gamma
\underline{f}}$ as $\gamma \to \IF$, where $\underline{f}$ is the projection of
$f$ on some closed convex subset of $\kHC$.


title:
Emergence of topological semimetals in gap closing in semiconductors
  without inversion symmetry

abstract:
  A band gap for electronic states in crystals governs various properties of
solids, such as transport, optical and magnetic properties. Its estimation and
control have been an important issue in solid state physics. The band gap can
be controlled externally by various parameters, such as pressure, atomic
compositions and external field. Sometimes, the gap even collapses by tuning
some parameter. In the field of topological insulators, such closing of the gap
at a time-reversal invariant momentum indicates a band inversion, i.e. it leads
to a topological phase transition from a normal insulator to a topological
insulator. Here we show that the gap losing in inversion-asymmetric crystals is
universal, in the sense that the gap closing always leads either to a Weyl
semimetal or a nodal-line semimetal, from an exhaustive study on possible space
groups. We here consider three-dimensional spinful systems with time-reversal
symmetry. The space group of the system and the wavevector at the gap closing
uniquely determine which possibility occurs and where the gap-closing points or
lines lie in the wavevector space after closing of the gap. In particular, we
show that an insulator-to-insulator transition never happens, which is in sharp
contrast with inversion-symmetric systems.


title:
On the equivalence of proportional-integral and proportional-resonant
  controllers with anti-windup

abstract:
  It is shown that proportional-integral (PI) control in the synchronously
rotating (d, q)-reference frame and proportional-resonant (PR) control in the
stationary ({\alpha}, \b{eta})-reference frame, both with anti-windup, are
equivalent if and only if their implementation is done correctly in state space
and the controller parameters and the initial values are identical. It is shown
that an equivalence in the frequency domain does only hold if simplifying
assumptions are satisfied. As consequence of the equivalence, both closed- loop
control performances are identical with respect to closed-loop dynamics and
steady-state accuracy. The control performance will only differ if their
implementation is not done correctly or the time delay induced by the voltage
source inverter becomes significant. To the best knowledge of the author,
equivalence of PR and PI controllers with anti-windup has not been shown before
(in particular not in state space).


title: Kinematic Space and Wormholes

abstract:
  The kinematic space could play a key role in constructing the bulk geometry
from dual CFT. In this paper, we study the kinematic space from geometric
points of view, without resorting to differential entropy. We find that the
kinematic space could be intrinsically defined in the embedding space. For each
oriented geodesic in the Poincar\'e disk, there is a corresponding point in the
kinematic space. This point is the tip of the causal diamond of the disk whose
intersection with the Poincar\'e disk determines the geodesic. In this
geometric construction, the causal structure in the kinematic space can be seen
clearly. Moreover, we find that every transformation in the $SL(2,\mathbb{R})$
leads to a geodesic in the kinematic space. In particular, for a hyperbolic
transformation defining a BTZ black hole, it is a timelike geodesic in the
kinematic space. We show that the horizon length of the static BTZ black hole
could be computed by the geodesic length of corresponding points in the
kinematic space. Furthermore, we discuss the fundamental regions in the
kinematic space for the BTZ blackhole and multi-boundary wormholes.


title: A new earthquake location method based on the waveform inversion

abstract:
  In this paper, a new earthquake location method based on the waveform
inversion is proposed. As is known to all, the waveform misfit function is very
sensitive to the phase shift between the synthetic waveform signal and the real
waveform signal. Thus, the convergence domain of the conventional waveform
based earthquake location methods is very small. In present study, by
introducing and solving a simple sub-optimization problem, we greatly expand
the convergence domain of the waveform based earthquake location method.
According to a large number of numerical experiments, the new method expands
the range of convergence by several tens of times. This allows us to locate the
earthquake accurately even from some relatively bad initial values.


title: The first Cheeger constant of a simplex

abstract:
  The coboundary expansion generalizes the classical graph expansion to the
case of the general simplicial complexes, and allows the definition of the
higher-dimensional Cheeger constants $h_k(X)$ for an arbitrary simplicial
complex $X$, and any $k\geq 0$. In this paper we investigate the value of
$h_1(\Delta^{[n]})$ - the first Cheeger constant of a simplex with $n$
vertices. It is known, due to the pioneering work of Meshulam and Wallach, that
\[\lceil n/3\rceil\geq h_1(\Delta^{[n]})\geq n/3, \textrm{ for all } n,\] and
that the equality $h_1(\Delta^{[n]})=n/3$ is achieved when $n$ is divisible by
$3$.
  Here we expand on these results. First, we show that \[h_1(\Delta^{[n]})=n/3,
\textrm{ whenever }n\textrm{ is not a power of }2.\] So the sharp equality
holds on a set whose density goes to $1$. Second, we show that
\[h_1(\Delta^{[n]})=n/3+O(1/n),\textrm{ when }n\textrm{ is a power of }2.\] In
other words, as $n$ goes to infinity, the value $h_1(\Delta^{[n]})-n/3$ is
either $0$ or goes to $0$ very rapidly.
  Our methods include recasting the original question in purely graph-theoretic
language, followed by a detailed investigation of a specific graph family, the
so-called {\it staircase graphs}. These are defined by associating a graph to
every partition, and appear to be especially suited to gain information about
the first Cheeger constant of a simplex.


title: Bosonic-Seesaw Portal Dark Matter

abstract:
  We discuss a new type of Higgs-portal dark matter (DM)-production mechanism,
called bosonic-seesaw portal (BSP) scenario. The BS provides the dynamical
origin of the electroweak symmetry breaking, triggered by mixing between the
elementary Higgs and a composite Higgs generated by a new-color strong
dynamics, hypercolor (HC). At the HC strong coupling scale, the classical-scale
invariance assumed in the model is dynamically broken as well as the "chiral"
symmetry present in the HC sector. In addition to the composite Higgs, HC
baryons emerge to potentially be stable because of the unbroken HC baryon
number symmetry. Hence the lightest HC baryon can be a DM candidate. Of
interest in the present scenario is that HC pions can be as heavy as the HC
baryon due to the possibly enhanced-explicit "chiral"-breaking effect triggered
after the BS mechanism, so the HC baryon pair cannot annihilate into HC pions.
As in the standard setup of freeze-in scenario, it is assumed that the DM was
never in the thermal equilibrium, which ends up with no thermal abundance. It
is then the non-thermal BSP process that crucially comes into the game below
the HC scale: the HC baryon significantly couples to the standard-model Higgs
via the BS mechanism, and can non-thermally be produced from the thermal plasma
below the HC scale, which turns out to allow the TeV mass scale for the
composite baryonic DM, much smaller than the generic bound placed in the
conventional thermal freeze-out scenario, to account for the observed relic
abundance. Thus the DM can closely be related to the mechanism of the
electroweak symmetry breaking.


title:
Higher moments of multiplicity fluctuations in a hadron-resonance gas
  with exact conservation laws

abstract:
  Higher moments of multiplicity fluctuations of hadrons produced in central
nucleus-nucleus collisions are studied within the hadron-resonance gas model in
the canonical ensemble. Exact conservation of three charges, baryon number,
electric charge, and strangeness, is enforced in the large volume limit.
Moments up to the forth order of various particles are calculated at SPS, RHIC
and LHC energies. The asymptotic fluctuations within a simplified model with
only one conserved charge in the canonical ensemble are discussed where simple
analytical expressions for moments of multiplicity distributions can be
obtained. Moments products of net-proton, net-kaon, and net-charge
distributions in Au + Au collisions at RHIC energies are calculated. The
pseudo-rapidity coverage dependence of net-charge fluctuation is discussed.


title:
A Monte Carlo Study of Flux Ratios of Raman Scattered O~VI Features at
  6825 \AA\ and 7082 \AA\ in Symbiotic Stars

abstract:
  Symbiotic stars are regarded as wide binary systems consisting of a hot white
dwarf and a mass losing giant. They exhibit unique spectral features at 6825
\AA\ and 7082 \AA, which are formed via Raman scattering of
\ion{O}{6}$\lambda\lambda$ 1032 and 1038 with atomic hydrogen. We adopt a Monte
Carlo technique to generate the same number of \ion{O}{6}$\lambda$1032 and
$\lambda$1038 line photons and compute the flux ratio $F(6825)/F(7082)$ of
these Raman scattered \ion{O}{6} features formed in neutral regions with a
simple geometric shape as a function of \ion{H}{1} column density $N_{HI}$. In
cylindrical and spherical neutral regions with the \ion{O}{6} source embedded
inside, the flux ratio $F(6825)/F(7082)$ shows an overall decrease from 3 to 1
as $N_{HI}$ increases in the range $10^{22-24}{\rm\ cm^{-2}}$. In the cases of
a slab geometry and other geometries with the \ion{O}{6} source outside the
\ion{H}{1} region, Rayleigh escape operates to lower the flux ratio
considerably. For moderate values of $N_{HI}\sim 10^{23}{\rm\ cm^{-2}}$ the
flux ratio behaves in a complicated way to exhibit a broad bump with a peak
value of 3.5 in the case of a sphere geometry. We find that the ratio of Raman
conversion efficiencies of \ion{O}{6}$\lambda\lambda$1032, 1038 ranges from 0.8
to 3.5. Our high resolution spectra of 'D' type HM~Sge and 'S' type AG~Dra
obtained with the {\it Canada-France-Hawaii-Telescope} show that the flux ratio
$F(6825)/F(7082)$ of AG~Dra is significantly smaller than that of HM~Sge,
implying that 'S' type symbiotics are characterized by higher $N_{HI}$ than 'D'
type symbiotics.


title: Finite Temperature Corrections to Tachyon Mass in Intersecting D-Branes

abstract:
  We continue with the analysis of finite temperature corrections to the
Tachyon mass in intersecting branes which was initiated in arxiv:1403.0389. In
this paper we extend the computation to the case of intersecting D3-branes by
considering a setup of two intersecting branes in flat-space background. A
holographic model dual to BCS superconductor consisting of intersecting
D8-branes in D4-brane background was proposed in arxiv:1104.2843. The
background considered here is a simplified configuration of this dual model. We
compute the one-loop Tachyon amplitude in the Yang-Mills approximation and show
that the result is finite. Analyzing the amplitudes further we numerically
compute the transition temperature at which the Tachyon becomes massless. The
analytic expressions for the one-loop amplitudes obtained here reduce to those
for intersecting D1-branes obtained in arxiv:1403.0389 as well as those for
intersecting D2-branes.


title: An Efficient Web Traffic Defence Against Timing-Analysis Attacks

abstract:
  We introduce a new class of lower overhead tunnel that is resistant to
traffic analysis. The tunnel opportunistically reduces the number of dummy
packets transmitted during busy times when many flows are simultaneously active
while maintaining well-defined privacy properties. We find that the dummy
packet overhead is typically less than 20% on lightly loaded links and falls to
zero as the traffic load increases i.e. the tunnel is capacity-achieving. The
additional latency incurred is less than 100ms. We build an experimental
prototype of the tunnel and carry out an extensive performance evaluation that
demonstrates its effectiveness under a range of network conditions and real web
page fetches.


title: Weyl Ferroelectric Semimetal

abstract:
  The recent discoveries of ferroelectric metal and Weyl semimetal (WSM) have
stimulated a natural question: whether these two exotic states of matter can
coexist in a single material or not. These two discoveries ensure us that
physically it is possible since both of them share the same necessary
condition, the broken inversion symmetry. Here, by using first-principles
calculations, we demonstrate that the experimentally synthesized nonmagnetic
HgPbO$_3$ represents a unique example of such hybrid "\emph{Weyl ferroelectric
semimetal}". Its centrosymmetric $R\bar{3}c$ phase will undergo a ferroelectric
phase transition to the ferroelectric $R3c$ structure. Both phases are metallic
and the ferroelectric phase owns a spontaneous polarization of 33
$\mu$C/cm$^2$. Most importantly, it also harbors six pairs of chiral Weyl nodes
around the Fermi level to be an oxide WSM. The structural symmetry broken phase
transition induces a topological phase transition. The coexistence of
ferroelectricity and Weyl nodes in HgPbO$_3$ is an ideal platform for exploring
multiphase interaction and mutual control. The Weyl nodes can be tuned by
external pulse electric field, which is promising for potential applications of
integrated topotronic and ferroelectric devices.


title: Physics potential of searching for $0\nu\beta\beta$ decays in JUNO

abstract:
  In the past few decades, numerous searches have been made for the
neutrinoless double-beta decay (0$\nu\beta\beta$) process, aiming to establish
whether neutrinos are their own antiparticles (Majorana neutrinos), but no
0$\nu\beta\beta$ decay signal has yet been observed. A number of new
experiments are proposed but they ultimately suffer from a common problem: the
sensitivity may not increase indefinitely with the target mass. We have
performed a detailed analysis of the physics potential by using the Jiangmen
Underground Neutrino Observatory (JUNO) to improve the sensitivity to
0$\nu\beta\beta$ up to a few meV, a major step forward with respect to the
experiments currently being planned. JUNO is a 20 kton low-background liquid
scintillator (LS) detector with 3\%/$\sqrt{E \text{(MeV)}}$ energy resolution,
now under construction. It is feasible to build a balloon filled with enriched
xenon gas (with $^{136}$Xe up to 80\%) dissolved in LS, inserted into the
central region of the JUNO LS. The energy resolution is $\sim$1.9\% at the
$Q$-value of $^{136}$Xe 0$\nu\beta\beta$ decay. Ultra-low background is the key
for 0$\nu\beta\beta$ decay searches. Detailed studies of background rates from
intrinsic 2$\nu\beta\beta$ and $^{8}$B solar neutrinos, natural radioactivity,
and cosmogenic radionuclides (including light isotopes and $^{137}$Xe) were
performed and several muon veto schemes were developed. We find that JUNO has
the potential to reach a sensitivity (at 90\% C. L.) to
$T^{0\nu\beta\beta}_{1/2}$ of $1.8\times10^{28}$ yr ($5.6\times10^{27}$ yr)
with $\sim$50 tons (5 tons) of fiducial $^{136}$Xe and 5 years exposure, while
in the 50-ton case the corresponding sensitivity to the effective neutrino
mass, $m_{\beta\beta}$, could reach (5--12) meV, covering completely the
allowed region of inverted neutrino mass ordering.


title: Bounded embeddings of graphs in the plane

abstract:
  A drawing in the plane ($\mathbb{R}^2$) of a graph $G=(V,E)$ equipped with a
function $\gamma: V \rightarrow \mathbb{N}$ is \emph{$x$-bounded} if (i) $x(u)
<x(v)$ whenever $\gamma(u)<\gamma(v)$ and (ii) $\gamma(u)\leq\gamma(w)\leq
\gamma(v)$, where $uv\in E$ and $\gamma(u)\leq \gamma(v)$, whenever $x(w)\in
x(uv)$, where $x(.)$ denotes the projection to the $x$-axis. We prove a
characterization of isotopy classes of graph embeddings in the plane containing
an $x$-bounded embedding. Then we present an efficient algorithm, that relies
on our result, for testing the existence of an $x$-bounded embedding if the
given graph is a tree or generalized $\Theta$-graph. This partially answers a
question raised recently by Angelini et al. and Chang et al., and proves that
c-planarity testing of flat clustered graphs with three clusters is tractable
if each connected component of the underlying abstract graph is a tree.


title: Sequential decision problems, dependent types and generic solutions

abstract:
  We present a computer-checked generic implementation for solving
finite-horizon sequential decision problems. This is a wide class of problems,
including inter-temporal optimizations, knapsack, optimal bracketing,
scheduling, etc. The implementation can handle time-step dependent control and
state spaces, and monadic representations of uncertainty (such as stochastic,
non-deterministic, fuzzy, or combinations thereof). This level of genericity is
achievable in a programming language with dependent types (we have used both
Idris and Agda). Dependent types are also the means that allow us to obtain a
formalization and computer-checked proof of the central component of our
implementation: Bellman's principle of optimality and the associated backwards
induction algorithm. The formalization clarifies certain aspects of backwards
induction and, by making explicit notions such as viability and reachability,
can serve as a starting point for a theory of controllability of monadic
dynamical systems, commonly encountered in, e.g., climate impact research.


title: Note on the butterfly effect in holographic superconductor models

abstract:
  In this note we remark that the butterfly effect can be used to diagnose the
phase transition of superconductivity in a holographic framework. Specifically,
we compute the butterfly velocity in a charged black hole background as well as
anisotropic backgrounds with Q-lattice structure. In both cases we find its
derivative to the temperature is discontinuous at critical points. We also
propose that the butterfly velocity can signalize the occurrence of thermal
phase transition in general holographic models.


title: Another characterization of homogeneous Poisson processes

abstract:
  For a general renewal process $N$ (allowing delay, defect and multiple
simultaneous arrivals) the independence of the first renewal epochs of the
marked processes got from $N$ by Bernoulli $0$/$1$ thinning is characterized.
This independence is well-known to hold true in the case of homogeneous Poisson
processes; by way of corollary one obtains the interesting observation that,
when coupled with some minimal extra conditions, it in fact already identifies
them. The proof is analytic in character.


title:
Revisiting optimal eavesdropping in quantum cryptography: Optimal
  interaction is unique up to rotation of the underlying basis

abstract:
  A general framework of optimal eavesdropping on BB84 protocol was provided by
Fuchs et al. [Phys. Rev. A, 1997]. An upper bound on mutual information was
derived, which could be achieved by a specific type of interaction and the
corresponding measurement. However, uniqueness of optimal interaction was posed
as an unsolved problem there and it has remained open for almost two decades
now. In this paper, we solve this open problem and establish the uniqueness of
optimal interaction up to rotation. The specific choice of optimal interaction
by Fuchs et al. is shown to be a special case of the form derived in our work.


title:
Two are Better than One: An Ensemble of Retrieval- and Generation-Based
  Dialog Systems

abstract:
  Open-domain human-computer conversation has attracted much attention in the
field of NLP. Contrary to rule- or template-based domain-specific dialog
systems, open-domain conversation usually requires data-driven approaches,
which can be roughly divided into two categories: retrieval-based and
generation-based systems. Retrieval systems search a user-issued utterance
(called a query) in a large database, and return a reply that best matches the
query. Generative approaches, typically based on recurrent neural networks
(RNNs), can synthesize new replies, but they suffer from the problem of
generating short, meaningless utterances. In this paper, we propose a novel
ensemble of retrieval-based and generation-based dialog systems in the open
domain. In our approach, the retrieved candidate, in addition to the original
query, is fed to an RNN-based reply generator, so that the neural model is
aware of more information. The generated reply is then fed back as a new
candidate for post-reranking. Experimental results show that such ensemble
outperforms each single part of it by a large margin.


title: Holomorphic Gromov's partial order

abstract:
  As in [5], we study holomorphic maps of positive degree between compact
complex manifolds, and prove that any holomorphic map of degree one from a
compact complex manifold to itself is biholomorphic. This conclusion confirms
that under a mild restriction the holomorphic Gromov relation ">_" is indeed a
partial order.


title:
In silico modeling of the rheological properties of covalently
  crosslinked collagen triple helices

abstract:
  Biomimetic hydrogels based on natural polymers are a promising class of
biomaterial, mimicking the natural extra-cellular matrix of biological tissues
and providing cues for cell attachment, proliferation and differentiation. With
a view to providing an upstream method to guide subsequent experimental design,
the aim of this study was to introduce a mathematical model that described the
rheological properties of a hydrogel system based on covalently crosslinked
collagen triple helices. In light of their organization, such gels exhibit
limited collagen bundling that cannot be described by existing fibril network
models. The model presented here treats collagen triple helices as discrete
semi-flexible polymers, permits full access to metrics for network
microstructure, and should provide a comprehensive understanding of the
parameter space associated with the development of such multi-functional
materials. Triple helical hydrogel networks were experimentally obtained via
reaction of type I collagen with both aromatic and aliphatic diacids. The
complex modulus G* was found from rheological testing in linear shear and
quantitatively compared to model predictions. In silico data from the
computational model successfully described the experimental trends in hydrogel
storage modulus with either (i) the concentration of collagen triple helices
during crosslinking reaction or (ii) the type of crosslinking segment
introduced in resulting hydrogel networks. This approach may pave the way to a
step change in the rational design of biomimetic triple helical collagen
systems with controlled multi-functionality.


title:
A Structurally Self-Assembled Peptide Nano-Architecture by One-Step
  Electrospinning

abstract:
  Self-assembling peptides (SAPs) have shown to offer great promise in
therapeutics and have the ability to undergo self-assembly and form ordered
nanostructures. However SAP gels are often associated with inherent weak and
transient mechanical properties and incorporation of them into polymeric
matrices is a route to enhance their mechanical stability. The aim of this work
was to incorporate P11-8 peptide (CH3COQQRFOWOFEQQNH2) within
poly(epsilon-caprolactone) (PCL) fibrous webs via one-step electrospinning,
aiming to establish the underlying relationships between spinning process,
molecular peptide conformation, and material internal architecture.
Electrospinning of PCL solutions (6% w/w) in hexafluoro-2-propanol (HFIP)
containing up to 40 mg/ml P11-8 resulted in the formation of fibres in both
nano- (10-100 nm) and submicron range (100-700 nm), in contrast to PCL only
webs, which displayed a predominantly submicron fibre distribution. FTIR and CD
spectroscopy on both PCL/peptide solutions and resulting electrospun webs
revealed monomeric and beta-sheet secondary conformation, respectively,
suggesting the occurrence of peptide self-assembly during electrospinning due
to solvent evaporation. The peptide concentration (0 -> 40 mg/ml) was found to
primarily affect the internal structure of the fabric at the nano-scale, whilst
water as well as cell culture medium contact angles were dramatically
decreased. Nearly no cytotoxic response (> 90% cell viability) was observed
when L929 mouse fibroblasts were cultured in contact with electrospun peptide
loaded samples. This novel nanofibrous architecture may be the basis for an
interesting material platform for e.g. hard tissue repair, in light of the
presence of the self assembled P11-8 in the PCL fibrous structure.


title:
Convex Splitting Method for the Calculation of Transition States of
  Energy Functional

abstract:
  Among numerical methods for partial differential equations arising from
steepest descent dynamics of energy functionals (e.g., Allen-Cahn and
Cahn-Hilliard equations), the convex splitting method is well-known to maintain
unconditional energy stability for a large time step size. In this work, we
show how to use the convex splitting idea to find transition states, i.e.,
index-1 saddle points of the same energy functionals. Based on the iterative
minimization formulation (IMF) for saddle points (SIAM J. Numer. Anal., vol.
53, p1786, 2015), we introduce the convex splitting method to minimize the
auxiliary functional at each cycle of the IMF. We present a general principle
of constructing convex splitting forms for these auxiliary functionals and show
how to avoid solving nonlinear equations. The new numerical scheme based on the
convex splitting method allows for large time step sizes. The new methods are
tested for the one dimensional Ginzburg-Landau energy functional in the search
of the Allen-Cahn or Cahn-Hilliard types of transition states. We provide the
numerical results of transition states for the two dimensional
Landau-Brazovskii energy functional for diblock copolymers.


title:
Geographic and seasonal influences on optical followup of gravitational
  wave events

abstract:
  We investigate the effects of observatory locations on the probability of
discovering optical/infrared counterparts of gravitational wave sources. We
show that for the LIGO--Virgo network, the odds of discovering optical/infrared
(OIR) counterparts show some latitude dependence, but weak or no longitudinal
dependence. A stronger effect is seen to arise from the timing of LIGO/Virgo
observing runs, with northern OIR observatories having better chances of
finding the counterparts in northern winters. Assuming identical technical
capabilities, the tentative mid-2017 three-detector network observing favors
southern OIR observatories for discovery of EM counterparts.


title: Strongly Gauduchon spaces

abstract:
  We define strongly Gauduchon spaces and the class SG which are generalization
of strongly Gauduchon manifolds in complex spaces. Comparing with the case of
Kahlerian, the strongly Gauduchon space and the class SG are similar to the
Kahler space and the Fujiki class C respectively. Some properties about these
complex spaces are obtained, and the relations between the strongly Gauduchon
spaces and the class SG are studied.


title:
Monitoring Mechanical Motion of Carbon Nanotube based Nanomotor by
  Optical Absorption Spectrum

abstract:
  The optical absorption spectrums of nanomotors made from double-wall carbon
nanotubes have been calculated with the time-dependent density functional based
tight binding method. When the outer short tube of the nanomotor moves along or
rotates around the inner long tube, the peaks in the spectrum will gradually
evolve and may shift periodically, the amplitude of which can be as large as
hundreds of meV. We show that the features and behaviors of the optical
absorption spectrum could be used to monitor the mechanical motions of the
double-wall carbon nanotube based nanomotor.


title:
A Profile Analysis of Raman-scattered O VI Bands at 6825 \AA\ and 7082
  \AA\ in Sanduleak's Star

abstract:
  We present a detailed modeling of the two broad bands observed at 6825 \AA\
and 7082 \AA\ in Sanduleak's star, a controversial object in the Large
Magellanic Cloud. These bands are known to originate from Raman-scattering of O
VI $\lambda\lambda$ 1032 and 1038 photons with atomic hydrogen and are only
observed in bona fide symbiotic stars. Our high-resolution spectrum obtained
with the Magellan Inamori Kyocera Echelle (MIKE) spectrograph at the
Magellan-Clay Telescope reveals, quite surprisingly, that the profiles of the
two bands look very different: while the Raman 6825 \AA\ band shows a single
broad profile with a redward extended bump, the Raman 7082 \AA\ band exhibits a
distinct triple-peak profile. Our model suggests that the O VI emission nebula
can be decomposed into a red, blue and central emission regions from an
accretion disk, a bipolar outflow and a further compact, optically thick
region. We also perform Monte Carlo simulations with the aim of fitting the
observed flux ratio $F(6825)/F(7082) \sim 4.5$, which indicate that the neutral
region in Sanduleak's star is characterized by the column density $N_{HI} \sim
1 \times 10^{23} {\rm\ cm^{-2}}$.


title: Orthogonal projection of a test configuration to vector fields

abstract:
  Given a polarized complex manifold, projection of a torus-equivariant test
configuration to holomorphic vector fields was introduced by G. Sz\'ekelyhidi,
as the limit of the associated $\mathbb{C}^*$-actions. We show that there
actually holds the moment convergence of the weight distributions. Our analytic
approach at the same time specifies the limit in terms of the weak geodesic ray
associated with the test configuration. Related to the result, we discuss about
the reduced $L^p$-norm of the test configuration in attempt to describe the
uniform K-stability of the polarization relative to the automorphism group.


title: Real-time Halfway Domain Reconstruction of Motion and Geometry

abstract:
  We present a novel approach for real-time joint reconstruction of 3D scene
motion and geometry from binocular stereo videos. Our approach is based on a
novel variational halfway-domain scene flow formulation, which allows us to
obtain highly accurate spatiotemporal reconstructions of shape and motion. We
solve the underlying optimization problem at real-time frame rates using a
novel data-parallel robust non-linear optimization strategy. Fast convergence
and large displacement flows are achieved by employing a novel hierarchy that
stores delta flows between hierarchy levels. High performance is obtained by
the introduction of a coarser warp grid that decouples the number of unknowns
from the input resolution of the images. We demonstrate our approach in a live
setup that is based on two commodity webcams, as well as on publicly available
video data. Our extensive experiments and evaluations show that our approach
produces high-quality dense reconstructions of 3D geometry and scene flow at
real-time frame rates, and compares favorably to the state of the art.


title: On Zermelo's theorem

abstract:
  A famous result in game theory known as Zermelo's theorem says that "in chess
either White can force a win, or Black can force a win, or both sides can force
at least a draw". The present paper extends this result to the class of all
finite-stage two-player games of complete information with alternating moves.
It is shown that in any such game either the first player has a winning
strategy, or the second player has a winning strategy, or both have unbeatable
strategies.


title: Stochastic inference with spiking neurons in the high-conductance state

abstract:
  The highly variable dynamics of neocortical circuits observed in vivo have
been hypothesized to represent a signature of ongoing stochastic inference but
stand in apparent contrast to the deterministic response of neurons measured in
vitro. Based on a propagation of the membrane autocorrelation across spike
bursts, we provide an analytical derivation of the neural activation function
that holds for a large parameter space, including the high-conductance state.
On this basis, we show how an ensemble of leaky integrate-and-fire neurons with
conductance-based synapses embedded in a spiking environment can attain the
correct firing statistics for sampling from a well-defined target distribution.
For recurrent networks, we examine convergence toward stationarity in computer
simulations and demonstrate sample-based Bayesian inference in a mixed
graphical model. This points to a new computational role of high-conductance
states and establishes a rigorous link between deterministic neuron models and
functional stochastic dynamics on the network level.

categories: q-bio.NC cond-mat.dis-nn cs.NE physics.bio-ph stat.ML


title: Categorifying rationalization

abstract:
  We solve a problem proposed by Khovanov by constructing, for any set of
primes $S$, a triangulated category (in fact a stable $\infty$-category) whose
Grothendieck group is $S^{-1}\mathbf{Z}$. More generally, for any exact
$\infty$-category $E$, we construct an exact $\infty$-category $S^{-1}E$ of
equivariant sheaves on the Cantor space with respect to an action of a dense
subgroup of the circle. We show that this $\infty$-category is precisely the
result of categorifying division by the primes in $S$. In particular,
$K_n(S^{-1}E)\cong S^{-1}K_n(E)$.


title:
On the behavior of sequences of solutions to U(1) Seiberg-Witten systems
  in dimension 4

abstract:
  This paper studies the behavior of sequences of solutions to Seiberg-Witten
like equations for a pair consisting of a Hermitian connection on a line bundle
over a 4-dimensional manifold and a section of the self-dual spinor bundle of a
complex Clifford module on the manifold. Examples include the cases where the
Clifford module is a direct sum of C2 bundles associated to SpinC structures;
and the case of the SU(2) Vafa-Witten equations with an Abelian ansatz.


title: Cocompletion of restriction categories

abstract:
  Restriction categories were introduced as a way of generalising the notion of
partial map categories. In this paper, we define cocomplete restriction
category, and give the free cocompletion of a small restriction category as a
suitably defined category of restriction presheaves. We also consider the case
where our restriction category is locally small.


title: On real bisectional curvature for Hermitian manifolds

abstract:
  Motivated by the recent work of Wu and Yau on the ampleness of canonical line
bundle for compact K\"ahler manifolds with negative holomorphic sectional
curvature, we introduce a new curvature notion called $\textbf{real bisectional
curvature}$ for Hermitian manifolds. When the metric is K\"ahler, this is just
the holomorphic sectional curvature $H$, and when the metric is non-K\"ahler,
it is slightly stronger than $H$. We classify compact Hermitian manifolds with
constant non-zero real bisectional curvature, and also slightly extend Wu-Yau's
theorem to the Hermitian case. The underlying reason for the extension is that
the Schwarz lemma of Wu-Yau works the same when the target metric is only
Hermitian but has nonpositive real bisectional curvature.


title:
Development of Yttrium alloy ion source and its application in
  nanofabrication

abstract:
  We present a new YAuSi Liquid Metal Alloy Ion Source (LMAIS), generating
focused ion beams of yttrium ions, and its prospective applications for
nanofabrication, sample preparation, lithographic and implantation processes.
Working parameters of the AuSiY LMAIS are similar to other gold-silicon based
LMAIS. We found anomalously high emission current of triple charged Yttrium
ions. Influence of Yttrium implantation on optical qualities of the implanted
ion-ensembles is shown in luminescence of co-implanted Erbium ions.


title:
Entropy spectrum of Lyapunov exponents for nonhyperbolic step
  skew-products and elliptic cocycles

abstract:
  We study the fiber Lyapunov exponents of step skew-product maps over a
complete shift of $N$, $N\ge2$, symbols and with $C^1$ diffeomorphisms of the
circle as fiber maps. The systems we study are transitive and genuinely
nonhyperbolic, exhibiting simultaneously ergodic measures with positive,
negative, and zero exponents. Examples of such systems arise from the
projective action of $2\times 2$ matrix cocycles and our results apply to an
open and dense subset of elliptic $\mathrm{SL}(2,\bR)$ cocycles. We derive a
multifractal analysis for the topological entropy of the level sets of Lyapunov
exponent. The results are formulated in terms of Legendre-Fenchel transforms of
restricted variational pressures, considering hyperbolic ergodic measures only,
as well as in terms of restricted variational principles of entropies of
ergodic measures with a given exponent. We show that the entropy of the level
sets is a continuous function of the Lyapunov exponent. The level set of the
zero exponent has positive, but not maximal, topological entropy. Under the
additional assumption of proximality, as for example for skew-products arising
from certain matrix cocycles, there exist two unique ergodic measures of
maximal entropy, one with negative and one with positive fiber Lyapunov
exponent.


title: Exact diagonalization of the truncated Bogoliubov Hamiltonian

abstract:
  The present short note is simply intended to communicate that I have
analytically diagonalized the Bogoliubov truncated Hamiltonian
$H_c$~\cite{Bogo1,Bogo2}, in an interacting bosonic gas. This is the natural
prosecution of my work~\cite{MS}, now denoted as (I), where the diagonalization
was performed only in the subspace corresponding to zero momentum collective
excitations (CE).


title: Interaction-Free Effects Between Distant Atoms

abstract:
  A Gedanken experiment is presented where an excited and a ground-state atom
are positioned such that, within the former's half-life time, they exchange a
photon with 50% probability. A measurement of their energy state will therefore
indicate in 50% of the cases that no photon was exchanged. Yet other
measurements would reveal that, by the mere possibility of exchange, the two
atoms have become entangled. Consequently, the "no exchange" result, apparently
precluding entanglement, is non-locally established between the atoms by this
very entanglement. This quantum-mechanical version of the ancient Liar Paradox
can be realized with already existing transmission schemes, with the addition
of Bell's theorem applied to the no-exchange cases. Under appropriate
probabilities, the initially-excited atom, still excited, can be entangled with
additional atoms time and again, or alternatively, exert multipartite nonlocal
correlations in an interaction free manner. When densely repeated several
times, this result also gives rise to the Quantum Zeno effect, again exerted
between distant atoms without photon exchange. We discuss these experiments as
variants of Interaction-Free-Measurement, now generalized for both spatial and
temporal uncertainties. We next employ weak measurements for elucidating the
paradox. Interpretational issues are discussed in the conclusion, and a
resolution is offered within the Two-State Vector Formalism and its new
Heisenberg framework.


title:
Design of beam optics for the Future Circular Collider e+e- -collider
  rings

abstract:
  A beam optics scheme has been designed for the Future Circular Collider-e+e-
(FCC-ee). The main characteristics of the design are: beam energy 45 to 175
GeV, 100 km circumference with two interaction points (IPs) per ring,
horizontal crossing angle of 30 mrad at the IP and the crab-waist scheme [1]
with local chromaticity correction. The crab-waist scheme is implemented within
the local chromaticity correction system without additional sextupoles, by
reducing the strength of one of the two sextupoles for vertical chromatic
correction at each side of the IP. So-called "tapering" of the magnets is
applied, which scales all fields of the magnets according to the local beam
energy to compensate for the effect of synchrotron radiation (SR) loss along
the ring. An asymmetric layout near the interaction region reduces the critical
energy of SR photons on the incoming side of the IP to values below 100 keV,
while matching the geometry to the beam line of the FCC proton collider
(FCC-hh) [2] as closely as possible. Sufficient transverse/longitudinal dynamic
aperture (DA) has been obtained, including major dynamical effects, to assure
an adequate beam lifetime in the presence of beamstrahlung and top-up
injection. In particular, a momentum acceptance larger than +/-2% has been
obtained, which is better than the momentum acceptance of typical collider
rings by about a factor of 2. The effects of the detector solenoids including
their compensation elements are taken into account as well as synchrotron
radiation in all magnets. The optics presented in this paper is a step toward a
full conceptual design for the collider. A number of issues have been
identified for further study.


title:
Numerical computation of a fractional derivative with non-local and
  non-singular kernel

abstract:
  A numerical scheme for solving fractional initial value problems involving
the Atangana-Baleanu fractional derivative is presented. Some examples for the
proposed method are included, both for equations and systems of fractional
initial value problems.


title:
Trend to equilibrium for a reaction-diffusion system modelling
  reversible enzyme reaction

abstract:
  A spatio-temporal evolution of chemicals appearing in a reversible enzyme
reaction and modelled by a four component reaction-diffusion system with the
reaction terms obtained by the law of mass action is considered. The large time
behaviour of the system is studied by means of entropy methods.


title: Multiphase hydrogen storage in nanocontainers

abstract:
  Hydrogen can be stored in containers or in materials. In materials it can
exist in molecular or atomic forms. The atomic form can further exist as
multiple phases. Molecular hydrogen can be adsorbed on the surface or can be
present inside the material. In the current work, we demonstrate for the first
time, a methodology to store hydrogen in nearly all conceivable forms. At the
heart of this strategy is the novel concept of storage of molecular hydrogen in
metal Pd nanocontainers. The existence of multiple phases of hydrogen is
confirmed by x ray diffraction, Raman spectroscopy, nuclear magnetic resonance
and pressure-composition isotherm measurements. Enhancement in storage capacity
as compared to nanocrystals of the same mass is observed (36 percent increase
at 1 atm and 25C). About 18 percent of the hydrogen stored is in the molecular
form and interestingly this is achieved at room temperature and 1 atm pressure.


title: Colouring simplicial complexes via the Lechuga-Murillo's model

abstract:
  L. Lechuga and A. Murillo showed that a non-oriented, simple, connected,
finite graph $G$ is $k$-colourable if and only if a certain pure Sullivan
algebra associated to $G$ and $k$ is not elliptic. In this paper, we extend
this result to simplicial complexes by means of several notions of colourings
of these objects.


title:
Not All Multi-Valued Partial CFL Functions Are Refined by Single-Valued
  Functions

abstract:
  Multi-valued partial CFL functions are functions computed along accepting
computation paths by one-way nondeterministic pushdown automata, equipped with
write-only output tapes, which are allowed to reject an input, in comparison
with single-valued partial CFL functions. We give an answer to a fundamental
question, raised by Konstantinidis, Santean, and Yu [Act. Inform. 43 (2007)
395-417], of whether all such multi-valued partial CFL functions can be refined
by single-valued partial CFL functions. We negatively solve this open question
by presenting a special multi-valued partial CFL function as an example
function and by proving that no refinement of this particular function becomes
a single-valued partial CFL function. This contrasts an early result of
Kobayashi [Inform. Control 15 (1969) 95-109] that multi-valued partial NFA
functions are always refined by single-valued NFA functions, where NFA
functions are computed by one-way nondeterministic finite automata with output
tapes. Our example function turns out to be unambiguously 2-valued, and thus we
obtain a stronger separation result, in which no refinement of unambiguously
2-valued partial CFL functions can be single-valued. For the proof of this
fact, we first introduce a new concept of colored automata having no output
tapes but having "colors," which can simulate pushdown automata equipped with
constant-space output tapes. We then conduct an extensive combinatorial
analysis on the behaviors of transition records of stack contents (called stack
histories) of these colored automata.


title:
Accurate eigenvalues of the Schr\"odinger equation with the potential
  $V(r)=V_{0}r^{\alpha}$

abstract:
  We calculate accurate eigenvalues of the Schr\"odinger equation with the
potential $V(r)=V_{0}r^{\alpha}$, $\alpha \geq -1$, $V_{0}\alpha >0$. We resort
to the Riccati-Pad\'e method that is based on a rational approximation to the
logarithmic derivative of the wavefunction. This approach applies when $\alpha
$ is a rational number.


title: Colouring of (P3UP2)-free graphs

abstract:
  The class of 2K2-free graphs and its various subclasses have been studied in
a variety of contexts. In this paper, we are concerned with the colouring of
(P3UP2)-free graphs, a super class of 2K2-free graphs. We derive a O(w^3) upper
bound for the chromatic number of (P3UP2)-free graphs, and sharper bounds for
(P3UP2), diamond)-free graphs, where w denotes the clique number. By applying
similar proof techniques we obtain chromatic bounds for (2K2, diamond)-free
graphs. The last two classes are perfect if w >=5 and >= 4 respectively.


title: Zero product determined Lie algebras

abstract:
  A Lie algebra $L$ over a field $\mathbb{F}$ is said to be zero product
determined (zpd) if every bilinear map $f:L\times L\to \mathbb{F}$ with the
property that $f(x,y)=0$ whenever $x$ and $y$ commute is a coboundary. The main
goal of the paper is to determine whether or not some important Lie algebras
are zpd. We show that the Galilei Lie algebra $\mathfrak{sl}_2\ltimes V$, where
$V$ is a simple $\mathfrak{sl}_2$-module, is zpd if and only if $\dim V =2$ or
$\dim V$ is odd. The class of zpd Lie algebras also includes the quantum torus
Lie algebras $\mathcal{L}_q$ and $\mathcal{L}^+_q$, the untwisted affine Lie
algebras, the Heisenberg Lie algebras, and all Lie algebras of dimension at
most $3$, while the class of non-zpd Lie algebras includes the
($4$-dimensional) aging Lie algebra $\mathfrak {age}(1)$ and all Lie algebras
of dimension more than $3$ in which only linearly dependent elements commute.
We also give some evidence of the usefulness of the concept of a zpd Lie
algebra by using it in the study of commutativity preserving linear maps.


title: Dual conformal transformations of smooth holographic Wilson loops

abstract:
  We study dual conformal transformations of minimal area surfaces in $AdS_5
\times S^5$ corresponding to holographic smooth Wilson loops and some other
related observables. To act with dual conformal transformations we map the
string solutions to the dual space by means of T-duality, then we apply a
conformal transformation and finally T-dualize back to the original space. The
transformation maps between string solutions with different boundary contours.
The boundary contours of the minimal surfaces are not mapped back to the AdS
boundary, and the regularized area of the surface changes.


title:
Analytical model of atomic-force-microscopy force curves in viscoelastic
  materials exhibiting power law relaxation

abstract:
  We propose an analytical model for the force-indentation relationship in
viscoelastic materials exhibiting a power law relaxation described by an
exponent n, where n = 1 represents the standard viscoelastic solid (SLS) model,
and n < 1 represents a fractional SLS model. To validate the model, we perform
nanoindentation measurements of poylacrylamide gels with atomic force
microscopy (AFM) force curves. We found exponents n < 1 that depends on the
bysacrylamide concentration. We also demonstrate that the fitting of AFM force
curves for varying load speeds can reproduce the dynamic viscoelastic
properties of those gels measured with dynamic force modulation methods.


title: Death and rebirth of neural activity in sparse inhibitory networks

abstract:
  In this paper, we clarify the mechanisms underlying a general phenomenon
present in pulse-coupled heterogeneous inhibitory networks: inhibition can
induce not only suppression of the neural activity, as expected, but it can
also promote neural reactivation. In particular, for globally coupled systems,
the number of firing neurons monotonically reduces upon increasing the strength
of inhibition (neurons' death). However, the random pruning of the connections
is able to reverse the action of inhibition, i.e. in a sparse network a
sufficiently strong synaptic strength can surprisingly promote, rather than
depress, the activity of the neurons (neurons' rebirth). Thus the number of
firing neurons reveals a minimum at some intermediate synaptic strength. We
show that this minimum signals a transition from a regime dominated by the
neurons with higher firing activity to a phase where all neurons are
effectively sub-threshold and their irregular firing is driven by current
fluctuations. We explain the origin of the transition by deriving an analytic
mean field formulation of the problem able to provide the fraction of active
neurons as well as the first two moments of their firing statistics. The
introduction of a synaptic time scale does not modify the main aspects of the
reported phenomenon. However, for sufficiently slow synapses the transition
becomes dramatic, the system passes from a perfectly regular evolution to an
irregular bursting dynamics. In this latter regime the model provides
predictions consistent with experimental findings for a specific class of
neurons, namely the medium spiny neurons in the striatum.


title: Weyl semimetals with a boundary at $z=0$ a photoemission study

abstract:
  We consider a Weyl semimetal with two nodes and derive the scattering
Hamiltonian in the presence of a boundary at $z=0$. We compute the
photoemission spectrum and demonstrate the presence of the Fermi arcs which
connect the two nodes. In the presence of an electric field parallel to the
scattering surface we observe the one dimensional chiral anomaly.


title: How to be Fair and Diverse?

abstract:
  Due to the recent cases of algorithmic bias in data-driven decision-making,
machine learning methods are being put under the microscope in order to
understand the root cause of these biases and how to correct them. Here, we
consider a basic algorithmic task that is central in machine learning:
subsampling from a large data set. Subsamples are used both as an end-goal in
data summarization (where fairness could either be a legal, political or moral
requirement) and to train algorithms (where biases in the samples are often a
source of bias in the resulting model). Consequently, there is a growing effort
to modify either the subsampling methods or the algorithms themselves in order
to ensure fairness. However, in doing so, a question that seems to be
overlooked is whether it is possible to produce fair subsamples that are also
adequately representative of the feature space of the data set - an important
and classic requirement in machine learning. Can diversity and fairness be
simultaneously ensured? We start by noting that, in some applications,
guaranteeing one does not necessarily guarantee the other, and a new approach
is required. Subsequently, we present an algorithmic framework which allows us
to produce both fair and diverse samples. Our experimental results on an image
summarization task show marked improvements in fairness without compromising
feature diversity by much, giving us the best of both the worlds.