title: Optimal incentives for collective intelligence

abstract:
  Collective intelligence is the ability of a group to perform more effectively
than any individual alone. Diversity among group members is a key condition for
the emergence of collective intelligence, but maintaining diversity is
challenging in the face of social pressure to imitate one's peers. We
investigate the role incentives play in maintaining useful diversity through an
evolutionary game-theoretic model of collective prediction. We show that
market-based incentive systems produce herding effects, reduce information
available to the group and suppress collective intelligence. In response, we
propose a new incentive scheme that rewards accurate minority predictions, and
show that this produces optimal diversity and collective predictive accuracy.
We conclude that real-world systems should reward those who have demonstrated
accuracy when majority opinion has been in error.


title: Wave functions for three electrons in a magnetic field

abstract:
  This manuscript is in progress and the first version was removed by decision
of the autors.


title:
Return probability and recurrence for the random walk driven by
  two-dimensional Gaussian free field

abstract:
  Given any $\gamma>0$ and for $\eta=\{\eta_v\}_{v\in \mathbb Z^2}$ denoting a
sample of the two-dimensional discrete Gaussian free field on $\mathbb Z^2$
pinned at the origin, we consider the random walk on~$\mathbb Z^2$ among random
conductances where the conductance of edge $(u, v)$ is given by
$\mathrm{e}^{\gamma(\eta_u + \eta_v)}$. We show that, for almost every~$\eta$,
this random walk is recurrent and that, with probability tending to~1 as $T\to
\infty$, the return probability at time~$2T$ decays as $T^{-1+o(1)}$. In
addition, we prove a version of subdiffusive behavior by showing that the
expected exit time from a ball of radius~$N$ scales as $N^{\psi(\gamma)+o(1)}$
with $\psi(\gamma)>2$ for all~$\gamma>0$. Our results rely on delicate control
of the effective resistance for this random network. In particular, we show
that the effective resistance between two vertices at Euclidean distance~$N$
behaves as~$N^{o(1)}$.


title:
Phase-field modeling of electric field induced poration of lipid
  membranes

abstract:
  In this work, a model and simulation method to study the dynamics of pore
formation and annihilation in a lipid membrane under an applied electric field
has been developed. A continuum-level diffusive interface model (phase-field)
method is applied to model the evolution of the pore in a lipid membrane patch.
The numerical method and results are presented.


title: Parity Breaking Medium and Squeeze Operators

abstract:
  The transition between a Minkowski space region and a parity breaking medium
domain is thoroughly discussed. The requirement of continuity of the field
operator content across the separating boundary of the two domains leads to
Bogolyubov transformations, squeezed pairs states and squeeze operators that
turn out to generate a functional SU(2) algebra. According to this algebraic
approach, the reflection and transmission probability amplitude across the
separating boundary are computed. The probability rate of the emission or
absorption of squeezed pairs out of the vacuum (generalization of the
Sauter-Schwinger-Nikishov formula) is obtained.


title:
Controlling and observing nonseparability of phonons created in
  time-dependent 1D atomic Bose condensates

abstract:
  We study the spectrum and entanglement of phonons produced by temporal
changes in homogeneous one-dimensional atomic condensates. To characterize the
experimentally accessible changes, we first consider the dynamics of the
condensate when varying the radial trapping frequency, separately studying two
regimes: an adiabatic one and an oscillatory one. Working in momentum space, we
then show that in situ measurements of the density-density correlation function
can be used to assess the nonseparability of the phonon state after such
changes. We also study time-of-flight (TOF) measurements, paying particular
attention to the role played by the adiabaticity of opening the trap on the
nonseparability of the final state of atoms. In both cases, we emphasize that
commuting measurements can suffice to assess nonseparability. Some recent
observations are analyzed, and we make proposals for future experiments.


title: Approximate analytic expression for the Skyrmions crystal

abstract:
  We find approximate solutions for the two-dimensional non-linear
{\Sigma}-model with Dzyalioshinkii-Moriya term, representing magnetic
Skyrmions. They are built in an analytic form, by pasting different approximate
solutions found in different regions of space. We verify that our construction
reproduces the phenomenology known from numerical solutions and Monte Carlo
simulations, giving rise to a Skyrmion lattice at an intermediate range of
magnetic field, flanked by spiral and ferromagnetic phases for low and high
magnetic field respectively.


title:
Help, It Looks Confusing: GUI Task Automation Through Demonstration and
  Follow-up Questions

abstract:
  Non-programming users should be able to create their own customized scripts
to perform computer-based tasks for them, just by demonstrating to the machine
how it's done. To that end, we develop a system prototype which
learns-by-demonstration called HILC (Help, It Looks Confusing). Users train
HILC to synthesize a task script by demonstrating the task, which produces the
needed screenshots and their corresponding mouse-keyboard signals. After the
demonstration, the user answers follow-up questions.
  We propose a user-in-the-loop framework that learns to generate scripts of
actions performed on visible elements of graphical applications. While pure
programming-by-demonstration is still unrealistic, we use quantitative and
qualitative experiments to show that non-programming users are willing and
effective at answering follow-up queries posed by our system. Our models of
events and appearance are surprisingly simple, but are combined effectively to
cope with varying amounts of supervision.
  The best available baseline, Sikuli Slides, struggled with the majority of
the tests in our user study experiments. The prototype with our proposed
approach successfully helped users accomplish simple linear tasks, complicated
tasks (monitoring, looping, and mixed), and tasks that span across multiple
executables. Even when both systems could ultimately perform a task, ours was
trained and refined by the user in less time.


title: Reinforcement Learning in Rich-Observation MDPs using Spectral Methods

abstract:
  Reinforcement learning (RL) in Markov decision processes (MDPs) with large
state spaces is a challenging problem. The performance of standard RL
algorithms degrades drastically with the dimensionality of state space.
However, in practice, these large MDPs typically incorporate a latent or hidden
low-dimensional structure. In this paper, we study the setting of
rich-observation Markov decision processes (ROMDP), where there are a small
number of hidden states which possess an injective mapping to the observation
states. In other words, every observation state is generated through a single
hidden state, and this mapping is unknown a priori. We introduce a spectral
decomposition method that consistently learns this mapping, and more
importantly, achieves it with low regret. The estimated mapping is integrated
into an optimistic RL algorithm (UCRL), which operates on the estimated hidden
space. We derive finite-time regret bounds for our algorithm with a weak
dependence on the dimensionality of the observed space. In fact, our algorithm
asymptotically achieves the same average regret as the oracle UCRL algorithm,
which has the knowledge of the mapping from hidden to observed spaces. Thus, we
derive an efficient spectral RL algorithm for ROMDPs.


title: Some Developments in Gribov's Approach to QCD

abstract:
  We review several developments in the formulation of QCD provided by the GZ
action. These include the GZ-action at finite temperature, the relation of the
horizon condition and the Kugo-Ojima confinement criterion, the relation of the
horizon condition and the dual-Meisssner effect, the alternative derivation of
the GZ action provided by the Maggiore-Schaden shift, and the spontaneous
breaking of BRST symmetry. We conclude with a proposal for the definition of
physical states in the presence of BRST breaking.


title:
Regularity and strict positivity of densities for the nonlinear
  stochastic heat equation

abstract:
  In this paper, we establish a necessary and sufficient condition for the
existence and regularity of the density of the solution to a semilinear
stochastic (fractional) heat equation with measure-valued initial conditions.
Under a mild cone condition for the diffusion coefficient, we establish the
smooth joint density at multiple points. The tool we use is Malliavin calculus.
The main ingredient is to prove that the solutions to a related stochastic
partial differential equation have negative moments of all orders. Because we
cannot prove $u(t,x)\in \mathbb{D}^\infty$ for measure-valued initial data, we
need a localized version of Malliavin calculus. Furthermore, we prove that the
(joint) density is strictly positive in the interior of the support of the law,
where we allow both measure-valued initial data and unbounded diffusion
coefficient. The criteria introduced by Bally and Pardoux [1] are no longer
applicable for the parabolic Anderson model. We have extended their criteria to
a localized version. Our general framework includes the parabolic Anderson
model as a special case.


title: Associated points and integral closure of modules

abstract:
  Let $X:=\mathrm{Spec}(R)$ be an affine Noetherian scheme, and $\mathcal{M}
\subset \mathcal{N}$ be a pair of finitely generated $R$-modules. Denote their
Rees algebras by $\mathcal{R}(\mathcal{M})$ and $\mathcal{R}(\mathcal{N})$. Let
$\mathcal{N}^{n}$ be the $n$th homogeneous component of
$\mathcal{R}(\mathcal{N})$ and let $\mathcal{M}^{n}$ be the image of the $n$th
homegeneous component of $\mathcal{R}(\mathcal{M})$ in $\mathcal{N}^n$. Denote
by $\overline{\mathcal{M}^{n}}$ be the integral closure of $\mathcal{M}^{n}$ in
$\mathcal{N}^{n}$. We prove that
$\mathrm{Ass}_{X}(\mathcal{N}^{n}/\overline{\mathcal{M}^{n}})$ and
$\mathrm{Ass}_{X}(\mathcal{N}^{n}/\mathcal{M}^{n})$ are asymptotically stable,
generalizing known results for the case where $\mathcal{M}$ is an ideal or
where $\mathcal{N}$ is a free module. Suppose either that $\mathcal{M}$ and
$\mathcal{N}$ are free at the generic point of each irreducible component of
$X$ or $\mathcal{N}$ is contained in a free $R$-module. When $X$ is universally
catenary, we prove a generalization of a classical result due to McAdam and
obtain a geometric classification of the points appearing in
$\mathrm{Ass}_{X}(\mathcal{N}^{n}/\overline{\mathcal{M}^{n}})$. Notably, we
show that if $x \in
\mathrm{Ass}_{X}(\mathcal{N}^{n}/\overline{\mathcal{M}^{n}})$ for some $n$,
then $x$ is the generic point of a codimension-one component of the nonfree
locus of $\mathcal{N}/\mathcal{M}$ or $x$ is a generic point of an irreducible
set in $X$ where the fiber dimension $\mathrm{Proj}(\mathcal{R}(\mathcal{M}))
\rightarrow X$ jumps. We prove a converse to this result without requiring $X$
to be universally catenary. Many of our results are stated and proved more
generally for standard graded algebras. Also, we recover, strengthen, and prove
a sort of converse of an important result of Kleiman and Thorup about integral
dependence of modules.


title:
A compatible high-order meshless method for the Stokes equations with
  applications to suspension flows

abstract:
  A stable numerical solution of the steady Stokes problem requires
compatibility between the choice of velocity and pressure approximation that
has traditionally proven problematic for meshless methods. In this work, we
present a discretization that couples a staggered scheme for pressure
approximation with a divergence-free velocity reconstruction to obtain an
adaptive, high-order, finite difference-like discretization that can be
efficiently solved with conventional algebraic multigrid techniques. We use
analytic benchmarks to demonstrate equal-order convergence for both velocity
and pressure when solving problems with curvilinear geometries. In order to
study problems in dense suspensions, we couple the solution for the flow to the
equations of motion for freely suspended particles in an implicit monolithic
scheme. The combination of high-order accuracy with fully-implicit schemes
allows the accurate resolution of stiff lubrication forces directly from the
solution of the Stokes problem without the need to introduce sub-grid
lubrication models.


title:
Competing instabilities, orbital ordering and splitting of band
  degeneracies from a parquet renormalization group analysis of a 4-pocket
  model for iron-based superconductors: application to FeSe

abstract:
  We report the results of a parquet renormalization group (RG) study of
competing instabilities in the full 2D four pocket, three orbital low-energy
model for iron-based superconductors. We derive and analyze the RG flow of the
couplings, which describe all symmetry-allowed interactions between low-energy
fermions. Despite that the number of the couplings is large, we argue that
there are only two stable fixed trajectories of the RG flow and one weakly
unstable fixed trajectory with a single unstable direction. Each fixed
trajectory has a finite basin of attraction in the space of initial system
parameters. On the stable trajectories, either interactions involving only
$d_{xz}$ and $d_{yz}$ or only $d_{xy}$ orbital components on the electron
pockets dominate, while on the weakly unstable trajectory interactions
involving $d_{xz}$ ($d_{yz}$) and $d_{xy}$ orbital states on the electron
pockets remain comparable. The behavior along the two stable fixed trajectories
has been analyzed earlier [A.V. Chubukov, M. Khodas, and R.M. Fernandes,
arXiv:1602.05503]. Here we focus on the system behavior along the weakly
unstable trajectory and apply the results to FeSe. We find, based on the
analysis of susceptibilities along this trajectory, that the leading
instability upon lowering the temperature is towards a {\it three-component}
d-wave orbital nematic order. Two components are the differences between
fermionic densities on $d_{xz}$ and $d_{yz}$ orbitals on hole pockets and on
electron pockets, and the third one is the difference between the densities of
$d_{xy}$ orbitals on the two electron pockets. We argue that this order is
consistent with the splitting of band degeneracies, observed in recent
photoemission data on FeSe by A. Fedorov et al [arXiv:1606.03022].


title: Zero-sum continuous-time Markov pure jump game over a fixed duration

abstract:
  This paper considers a two-person zero-sum continuous-time Markov pure jump
game in Borel state and action spaces over a fixed finite horizon. The main
assumption on the model is the existence of a drift function, which bounds the
reward rate. Under some regularity conditions, we show that the game has a
value, and both of the players have their optimal policies.


title: Statistics of Reconnection-Driven Turbulence

abstract:
  Magnetic reconnection is a process that changes magnetic field topology in
highly conducting fluids. Within the standard Sweet-Parker model, this process
would be too slow to explain observations (e.g. solar flares). In reality, the
process must be ubiquitous as astrophysical fluids are magnetized and motions
of fluid elements necessarily entail crossing of magnetic frozen-in field lines
and magnetic reconnection. In the presence of turbulence, the reconnection is
independent of microscopic plasma properties, and may be much faster than
previously thought, as proposed in Lazarian & Vishniac (1999) and tested in
Kowal et al. (2009, 2012). However, the considered turbulence in the
Lazarian-Vishniac model was imposed externally. In this work we consider
reconnection-driven magnetized turbulence in realistic three-dimensional
geometry initiated by stochastic noise. We demonstrate through numerical
simulations that the stochastic reconnection is able to self-generate
turbulence through interactions between its outflows. We analyze the
statistical properties of velocity fluctuations using power spectra and
anisotropy scaling, which demonstrates that the reconnection produces
Kolmogorov-like turbulence, compatible with Goldreich-Sridhar (1995) model.
Anisotropy statistics are, however, strongly affected by the dynamics of
reconnection outflows. Once the broad turbulent region is formed, the typical
anisotropy scaling $l_\parallel \propto l_\perp^{2/3}$ is formed, especially
for high resolution models, were the broader range of scales is available. The
decay of reconnection outflows to turbulent-like fluctuations, characterized by
different anisotropy scalings, strongly depends on $\beta$ plasma. Moreover,
the estimated reconnection rates are weakly dependent on the resolution,
suggesting that no external processes are required to make reconnection fast.

categories: astro-ph.GA astro-ph.HE astro-ph.SR physics.plasm-ph physics.space-ph


title:
When Fashion Meets Big Data: Discriminative Mining of Best Selling
  Clothing Features

abstract:
  With the prevalence of e-commence websites and the ease of online shopping,
consumers are embracing huge amounts of various options in products.
Undeniably, shopping is one of the most essential activities in our society and
studying consumer's shopping behavior is important for the industry as well as
sociology and psychology. Indisputable, one of the most popular e-commerce
categories is clothing business. There arises the needs for analysis of popular
and attractive clothing features which could further boost many emerging
applications, such as clothing recommendation and advertising. In this work, we
design a novel system that consists of three major components: 1) exploring and
organizing a large-scale clothing dataset from a online shopping website, 2)
pruning and extracting images of best-selling products in clothing item data
and user transaction history, and 3) utilizing a machine learning based
approach to discovering fine-grained clothing attributes as the representative
and discriminative characteristics of popular clothing style elements. Through
the experiments over a large-scale online clothing shopping dataset, we
demonstrate the effectiveness of our proposed system, and obtain useful
insights on clothing consumption trends and profitable clothing features.


title:
A KIM-compliant potfit for fitting sloppy interatomic potentials:
  Application to the EDIP model for silicon

abstract:
  Fitted interatomic potentials are widely used in atomistic simulations thanks
to their ability to compute the energy and forces on atoms quickly. However,
the simulation results crucially depend on the quality of the potential being
used. Force matching is a method aimed at constructing reliable and
transferable interatomic potentials by matching the forces computed by the
potential as closely as possible, with those obtained from first principles
calculations. The potfit program is an implementation of the force-matching
method that optimizes the potential parameters using a global minimization
algorithm followed by a local minimization polish. We extended potfit in two
ways. First, we adapted the code to be compliant with the KIM Application
Programming Interface (API) standard (part of the Knowledgebase of Interatomic
Models Project). This makes it possible to use potfit to fit many KIM potential
models, not just those prebuilt into the potfit code. Second, we incorporated
the geodesic Levenberg--Marquardt (LM) minimization algorithm into potfit as a
new local minimization algorithm. The extended potfit was tested by generating
a training set using the KIM Environment-Dependent Interatomic Potential (EDIP)
model for silicon and using potfit to recover the potential parameters from
different initial guesses. The results show that EDIP is a "sloppy model" in
the sense that its predictions are insensitive to some of its parameters, which
makes fitting more difficult. We find that the geodesic LM algorithm is
particularly efficient for this case. The extended potfit code is the first
step in developing a KIM-based fitting framework for interatomic potentials for
bulk and two dimensional materials. The code is available for download via
https://www.potfit.net.


title: Interaction of a vortex induced by a rotating cylinder with a plane

abstract:
  In this article,we study theoretically and numerically the interaction of a
vortex induced by a rotating cylinder with a perpendicular plane. We show the
existence of weak solutions to the swirling vortex models by using the Hopf
extension method, and by an elegant contradiction argument, respectively. We
demonstrate numerically that the model could produce phenomena of swirling
vortex including boundary layer pumping and two-celled vortex that are observed
in potential line vortex interacting with a plane and in a tornado.


title: A caracter\'istica de Euler-Poincar\'e

abstract:
  We introduce the Euler-Poincar\'e's characteristic with an elementary way and
historically. We explain also why one should call Descartes-Poincar\'e
characteristic instead of the Euler-Poincar\'e's characteristic. All the
considered spaces are compact and without boundary. We work essentially on
smooth and oriented surfaces . However, we work also on singular and
non-oriented surfaces. We provide also the results which may be extended for
the case of superior dimension.


title: Additive Collatz Trajectories

abstract:
  Collatz Conjecture (also known as Ulam's conjecture and 3x+1 problem)
concerns the behavior of the iterates of a particular function on natural
numbers. A number of generalizations of the conjecture have been subjected to
extensive study. This paper explores Additive Collatz Trajectories, a
particular case of a generalization of Collatz conjecture and puts forward a
sufficient and necessary condition for looping of Additive Collatz
Trajectories, along with two minor results. An algorithm to compute the number
of equivalence classes when natural numbers are quotiented by the limiting
behavior of their corresponding trajectories is also proposed.


title: Sunspot and starspot lifetimes in a turbulent erosion model

abstract:
  Quantitative models of sunspot and starspot decay predict the timescale of
magnetic diffusion and may yield important constraints in stellar dynamo
models. Motivated by recent measurements of starspot lifetimes, we investigate
the disintegration of a magnetic flux tube by nonlinear diffusion. Previous
theoretical studies are extended by considering two physically motivated
functional forms for the nonlinear diffusion coefficient $D$: an inverse
power-law dependence $D \propto B^{-\nu}$ and a step-function dependence of $D$
on the magnetic field magnitude $B$. Analytical self-similar solutions are
presented for the power-law case, including solutions exhibiting "superfast"
diffusion. For the step-function case, the heat-balance integral method yields
approximate solutions, valid for moderately suppressed diffusion in the spot.
The accuracy of the resulting solutions is confirmed numerically, using a
method which provides an accurate description of long-time evolution by
imposing boundary conditions at infinite distance from the spot. The new models
may allow insight into differences and similarities between sunspots and
starspots.


title: Finite-state independence

abstract:
  In this work we introduce a notion of independence based on finite-state
automata: two infinite words are independent if no one helps to compress the
other using one-to-one finite-state transducers with auxiliary input. We prove
that, as expected, the set of independent pairs of infinite words has Lebesgue
measure 1. We show that the join of two independent normal words is normal.
However, the independence of two normal words is not guaranteed if we just
require that their join is normal. To prove this we construct a normal word
$x_1x_2x_3\ldots$ where $x_{2n}=x_n$ for every $n$.


title:
The Herschel-ATLAS: a sample of 500{\mu}m-selected lensed galaxies over
  600 square degrees

abstract:
  We present a sample of 80 candidate strongly lensed galaxies with flux
density above 100mJy at 500{\mu}m extracted from the Herschel Astrophysical
Terahertz Large Area Survey (H-ATLAS), over an area of 600 square degrees.
Available imaging and spectroscopic data allow us to confirm the strong lensing
in 20 cases and to reject it in one case. For other 8 objects the lensing
scenario is strongly supported by the presence of two sources along the same
line of sight with distinct photometric redshifts. The remaining objects await
more follow-up observations to confirm their nature. The lenses and the
background sources have median redshifts z_L = 0.6 and z_S = 2.5, respectively,
and are observed out to z_L = 1.2 and z_S = 4.2. We measure the number counts
of candidate lensed galaxies at 500{\mu}m and compare them with theoretical
predictions, finding a good agreement for a maximum magnification of the
background sources in the range 10-20. These values are consistent with the
magnification factors derived from the lens modelling of individual systems.
The catalogue presented here provides sub- mm bright targets for follow-up
observations aimed at exploiting gravitational lensing to study with
un-precedented details the morphological and dynamical properties of dusty star
forming regions in z >~ 1.5 galaxies.


title: Self-consistent Green's function approaches

abstract:
  We present the fundamental techniques and working equations of many-body
Green's function theory for calculating ground state properties and the
spectral strength. Green's function methods closely relate to other polynomial
scaling approaches discussed in chapters 8 and 10. However, here we aim
directly at a global view of the many-fermion structure. We derive the working
equations for calculating many-body propagators, using both the Algebraic
Diagrammatic Construction technique and the self-consistent formalism at finite
temperature. Their implementation is discussed, as well as the inclusion of
three-nucleon interactions. The self-consistency feature is essential to
guarantee thermodynamic consistency. The pairing and neutron matter models
introduced in previous chapters are solved and compared with the other methods
in this book.


title: Robust MPC via Min-Max Differential Inequalities

abstract:
  This paper is concerned with tube-based model predictive control (MPC) for
both linear and nonlinear, input-affine continuous-time dynamic systems that
are affected by time-varying disturbances. We derive a min-max differential
inequality describing the support function of positive robust forward invariant
tubes, which can be used to construct a variety of tube-based model predictive
controllers. These constructions are conservative, but computationally
tractable and their complexity scales linearly with the length of the
prediction horizon. In contrast to many existing tube-based MPC
implementations, the proposed framework does not involve discretizing the
control policy and, therefore, the conservatism of the predicted tube depends
solely on the accuracy of the set parameterization. The proposed approach is
then used to construct a robust MPC scheme based on tubes with ellipsoidal
cross-sections. This ellipsoidal MPC scheme is based on solving an optimal
control problem under linear matrix inequality constraints. We illustrate these
results with the numerical case study of a spring-mass-damper system.


title: Geometry-dependent constitutive law for granular slow frictional drag

abstract:
  Frictional constitutive law for very slow vertical withdrawing of a thin rod
from a granular bed is experimentally studied. Using a very precise creep
meter, geometry-dependent granular frictional constitutive law is particularly
examined. In some previous works, a dimensionless number
$I=\dot{\gamma}D_g/\sqrt{p/\rho_g}$ has been used to characterize granular
frictional constitutive laws, where $\dot{\gamma}$, $D_g$, $p$, and $\rho_g$
are the shear strain rate, grain diameter, confining pressure, and bulk density
of granular bed, respectively. It has been considered that granular frictional
constitutive law expressed by $I$ is universal (almost geometry-independent) in
dense flow regime. In this study, however, we find that the geometry of the
system is much more crucial to characterize granular friction in a very slow
withdrawing regime. Specifically, the ratio between rod and grain diameters
must be an essential parameter to describe the granular frictional constitutive
law. Physical meaning of the geometry-dependent constitutive law is discussed
on the basis of grains-contact-number dependence of granular behavior.


title:
Upper critical magnetic field of $Ln$O$_{0.5}$F$_{0.5}$BiS$_2$ ($Ln$ =
  La, Nd) superconductors at ambient and high pressure

abstract:
  The upper critical field $H_{c2}$ of polycrystalline samples of
$Ln$O$_{0.5}$F$_{0.5}$BiS$_{2}$ ($Ln$ = La, Nd) at ambient pressure (tetragonal
structure) and high pressure (HP) (monoclinic structure) have been investigated
via electrical resistivity measurements at various magnetic fields up to 8.5 T.
The $H_{c2}$($T$) curves for all the samples show an uncharacteristic concave
upward curvature at temperatures below $T_c$, which cannot be described by the
conventional one-band Werthamer-Helfand-Hohenberg theory. For the
LaO$_{0.5}$F$_{0.5}$BiS$_{2}$ sample under HP, as temperature is decreased, the
upper critical field $H_{onset}$, estimated from the onset of the
superconducting transitions, increases slowly between 4.9 and 5.8 T compared
with the slope of $H_{onset}$($T$) below 4.9 T and above 5.8 T. This anomalous
behavior reveals a remarkable similarity in superconductivity between
LaO$_{0.5}$F$_{0.5}$BiS$_{2}$ samples measured under HP and synthesized under
HP, although the crystal structures of the two samples were reported to be
different. The experimental results support the idea that local atomic
environment, which can be tuned by applying external pressure and can be
quenched to ambient pressure via high temperature-pressure annealing, is
possibly more essential to the enhancement of $T_c$ for BiS$_2$-based
superconductors than the structural phase transition. On the other hand, such
anomalous behavior is very subtle in the case of NdO$_{0.5}$F$_{0.5}$BiS$_{2}$
under HP, suggesting that the anisotropy of the upper critical field in the
$ab$-plane and the possible lattice deformation induced by external pressure is
weak. This explains why the pressure-induced enhancement of $T_c$ for
NdO$_{0.5}$F$_{0.5}$BiS$_{2}$ is not as large as that for
LaO$_{0.5}$F$_{0.5}$BiS$_{2}$.


title:
Statistical properties of gravity-driven granular discharge flow under
  the influence of an obstacle

abstract:
  Two-dimensional granular discharge flow driven by gravity under the influence
of an obstacle is experimentally investigated. A horizontal exit of width $W$
is opened at the bottom of vertical Hele-Shaw cell filled with stainless-steel
particles to start the discharge flow. In this experiment, a circular obstacle
is placed in front of the exit. Thus, the distance between the exit and
obstacle $L$ is also an important parameter. During the discharge,
granular-flow state is acquired by a high-speed camera. The bulk discharge-flow
rate is also measured by load cell sensors. The obtained high-speed-image data
are analyzed to clarify the particle-level granular-flow dynamics. Using the
measured data, we find that the obstacle above the exit affects the
granular-flow field. Specifically, the existence of obstacle results in large
horizontal granular temperature and small packing fraction. This tendency
becomes significant when $L$ is smaller than approximately 6$D_g$ when $W
\simeq 4 D_g$, where $D_g$ is diameter of particles.


title: Universal Partial Words over Non-Binary Alphabets

abstract:
  Chen, Kitaev, M\"{u}tze, and Sun recently introduced the notion of universal
partial words, a generalization of universal words and de Bruijn sequences.
Universal partial words allow for a wild-card character $\diamond$, which is a
placeholder for any letter in the alphabet. We settle and strengthen
conjectures posed in the same paper where this notion was introduced. For
non-binary alphabets, we show that universal partial words have periodic
$\diamond$ structure and are cyclic, and we give number-theoretic conditions on
the existence of universal partial words. In addition, we provide an explicit
construction for a family of universal partial words over alphabets of even
size.


title: Operational extreme points and Cuntz's canonical endomorphism

abstract:
  Based on the fact that the Cuntz algebra $O_n$ is generated by the operators
consisting of a finite operatorional partition, we study the notion of
operational extreme points (which we introduce here) by using several
completely positive maps on $O_n$. As a typical example, we show that the
Cuntz's canonical endomorphism $Phi_n$ is an operational extreme point in the
set of completely positive maps on $O_n$ and that it induces a completely
positive map which is extreme but not operational extreme, etc.


title:
Uniqueness in the inverse boundary value problem for piecewise
  homogeneous anisotropic elasticity

abstract:
  Consider a three dimensional piecewise homogeneous anisotropic elastic medium
$\Omega$ which is a bounded domain consisting of a finite number of bounded
subdomains $D_\alpha$, with each $D_\alpha$ a homogeneous elastic medium. One
typical example is a finite element model with elements with curvilinear
interfaces for an ansiotropic elastic medium. Assuming the $D_\alpha$ are known
and Lipschitz, we are concerned with the uniqueness in the inverse boundary
value problem of identifying the anisotropic elasticity tensor on $\Omega$ from
a localized Dirichlet to Neumann map given on a part of the boundary $\partial
D_{\alpha_0}\cap\partial\Omega$ of $\partial\Omega$ for a single $\alpha_0$,
where $\partial D_{\alpha_0}$ denotes the boundary of $ D_{\alpha_0}$. If we
can connect each $D_\alpha$ to $D_{\alpha_0}$ by a chain of
$\{D_{\alpha_i}\}_{i=1}^n$ such that interfaces between adjacent regions
contain a curved portion, we obtain global uniqueness for this inverse boundary
value problem. If the $D_\alpha$ are not known but are subanalytic subsets of
$\mathbb{R}^3$ with curved boundaries, then we also obtain global uniqueness.


title:
On the Brauer $p$-dimension of Henselian discrete valued fields of
  residual characteristic $p > 0$

abstract:
  Let $(K, v)$ be a Henselian discrete valued field with residue field
$\widehat K$ of characteristic $p$, and Brd$_{p}(K)$ be the Brauer
$p$-dimension of $K$. This paper shows that Brd$_{p}(K) \ge n$, if $[\widehat
K\colon \widehat K ^{p}] = p ^{n}$, for some $n \in \mathbb{N}$. It proves that
Brd$_{p}(K) = \infty $ if and only if $[\widehat K\colon \widehat K ^{p}] =
\infty $.


title: Training IBM Watson using Automatically Generated Question-Answer Pairs

abstract:
  IBM Watson is a cognitive computing system capable of question answering in
natural languages. It is believed that IBM Watson can understand large corpora
and answer relevant questions more effectively than any other
question-answering system currently available. To unleash the full power of
Watson, however, we need to train its instance with a large number of
well-prepared question-answer pairs. Obviously, manually generating such pairs
in a large quantity is prohibitively time consuming and significantly limits
the efficiency of Watson's training. Recently, a large-scale dataset of over 30
million question-answer pairs was reported. Under the assumption that using
such an automatically generated dataset could relieve the burden of manual
question-answer generation, we tried to use this dataset to train an instance
of Watson and checked the training efficiency and accuracy. According to our
experiments, using this auto-generated dataset was effective for training
Watson, complementing manually crafted question-answer pairs. To the best of
the authors' knowledge, this work is the first attempt to use a large-scale
dataset of automatically generated question-answer pairs for training IBM
Watson. We anticipate that the insights and lessons obtained from our
experiments will be useful for researchers who want to expedite Watson training
leveraged by automatically generated question-answer pairs.


title:
Existence of self-shrinkers to the degree-one curvature flow with a
  rotationally symmetric conical end

abstract:
  Given a smooth, symmetric, homogeneous of degree one function
$f\left(\lambda_{1},\cdots,\,\lambda_{n}\right)$ satisfying $\partial_{i}f>0$
for all $i=1,\cdots,\,n$, and a rotationally symmetric cone $\mathcal{C}$ in
$\mathbb{R}^{n+1}$, we show that there is a $f$ self-shrinker (i.e. a
hypersurface $\Sigma$ in $\mathbb{R}^{n+1}$ which satisfies
$f\left(\kappa_{1},\cdots,\,\kappa_{n}\right)+\frac{1}{2}X\cdot N=0$, where $X$
is the position vector, $N$ is the unit normal vector, and
$\kappa_{1},\cdots,\,\kappa_{n}$ are principal curvatures of $\Sigma$) that is
asymptotic to $\mathcal{C}$ at infinity.


title: Personalized Donor-Recipient Matching for Organ Transplantation

abstract:
  Organ transplants can improve the life expectancy and quality of life for the
recipient but carries the risk of serious post-operative complications, such as
septic shock and organ rejection. The probability of a successful transplant
depends in a very subtle fashion on compatibility between the donor and the
recipient but current medical practice is short of domain knowledge regarding
the complex nature of recipient-donor compatibility. Hence a data-driven
approach for learning compatibility has the potential for significant
improvements in match quality. This paper proposes a novel system
(ConfidentMatch) that is trained using data from electronic health records.
ConfidentMatch predicts the success of an organ transplant (in terms of the 3
year survival rates) on the basis of clinical and demographic traits of the
donor and recipient. ConfidentMatch captures the heterogeneity of the donor and
recipient traits by optimally dividing the feature space into clusters and
constructing different optimal predictive models to each cluster. The system
controls the complexity of the learned predictive model in a way that allows
for assuring more granular and confident predictions for a larger number of
potential recipient-donor pairs, thereby ensuring that predictions are
"personalized" and tailored to individual characteristics to the finest
possible granularity. Experiments conducted on the UNOS heart transplant
dataset show the superiority of the prognostic value of ConfidentMatch to other
competing benchmarks; ConfidentMatch can provide predictions of success with
95% confidence for 5,489 patients of a total population of 9,620 patients,
which corresponds to 410 more patients than the most competitive benchmark
algorithm (DeepBoost).


title:
An Elementary Proof of Convex Phase Retrieval in the Natural Parameter
  Space via the Linear Program PhaseMax

abstract:
  The phase retrieval problem has garnered significant attention since the
development of the PhaseLift algorithm, which is a convex program that operates
in a lifted space of matrices. Because of the substantial computational cost
due to lifting, many approaches to phase retrieval have been developed,
including non-convex optimization algorithms which operate in the natural
parameter space, such as Wirtinger Flow. Very recently, a convex formulation
called PhaseMax has been discovered, and it has been proven to achieve phase
retrieval via linear programming in the natural parameter space under optimal
sample complexity. The current proofs of PhaseMax rely on statistical learning
theory or geometric probability theory. Here, we present a short and elementary
proof that PhaseMax exactly recovers real-valued vectors from random
measurements under optimal sample complexity. Our proof only relies on standard
probabilistic concentration and covering arguments, yielding a simpler and more
direct proof than those that require statistical learning theory, geometric
probability or the highly technical arguments for Wirtinger Flow-like
approaches.


title:
Decoupling of Mixed Methods Based on Generalized Helmholtz
  Decompositions

abstract:
  A framework to systematically decouple high order elliptic equations into
combination of Poisson-type and Stokes-type equations is developed. The key is
to systematically construct the underling commutative diagrams involving the
complexes and Helmholtz decompositions in a general way. Discretizing the
decoupled formulation leads to a natural superconvergence between the Galerkin
projection and the decoupled approximation. Examples include but not limit to:
the primal formulations and mixed formulations of biharmonic equation, fourth
order curl equation, and triharmonic equation etc. As a by-product, Helmholtz
decompositions for many dual spaces are obtained.


title:
All-optical switching via four-wave mixing Bragg scattering in a silicon
  platform

abstract:
  We employ the process of non-degenerate four-wave mixing Bragg scattering
(FWM-BS) to demonstrate all-optical control in a silicon platform. In our
configuration, a strong, non-information-carrying pump is mixed with a weak
control pump and an input signal in a silicon-on-insulator waveguide. Through
the optical nonlinearity of this highly-confining waveguide, the weak pump
controls the wavelength conversion process from the signal to an idler, leading
to a controlled depletion of the signal. The strong pump, on the other hand,
plays the role of a constant bias. In this work, we show experimentally that it
is possible to implement this low-power switching technique as a first step
towards universal optical logic gates, and test the performance with random
binary data. Even at very low powers, where the signal and control pump levels
are almost equal, the eye-diagrams remain open, indicating a successful
operation of the logic gates.


title: Subdirect sums of Lie algebras

abstract:
  We show Lie algebra versions of some results on homological finiteness
properties of subdirect products of groups, including a version of the 1-2-3
Theorem.


title: A Frobenius-Nirenberg theorem with parameter

abstract:
  The Newlander-Nirenberg theorem says that a formally integrable complex
structure is locally equivalent to the complex structure in the complex
Euclidean space. We will show two results about the Newlander-Nirenberg theorem
with parameter. The first extends the Newlander-Nirenberg theorem to a
parametric version, and its proof yields a sharp regularity result as Webster's
proof for the Newlander-Nirenberg theorem. The second concerns a version of
Nirenberg's complex Frobenius theorem and its proof yields a result with a mild
loss of regularity.


title: Sequences of Integers with Three Missing Separations

abstract:
  Fix a set $D$ of positive integers. We study the maximum density $\mu(D)$ of
sequences of integers in which the separation between any two terms does not
fall in $D$. The $D$-sets considered in this article are of the form
$\{1,j,k\}$. The closely related function $\kappa(D)$, the parameter involved
in the "lonely runner conjecture," is also investigated. Exact values of
$\kappa(D)$ and $\mu(D)$ are found for some families of $D=\{1,j,k\}$. We prove
that the boundary conditions in two earlier results of Haralambis are sharp.
Consequently, our results declaim two conjectures posted recently, and extend
some results by Gupta.


title: Anomaly Detection in Bitcoin Network Using Unsupervised Learning Methods

abstract:
  The problem of anomaly detection has been studied for a long time. In short,
anomalies are abnormal or unlikely things. In financial networks, thieves and
illegal activities are often anomalous in nature. Members of a network want to
detect anomalies as soon as possible to prevent them from harming the network's
community and integrity. Many Machine Learning techniques have been proposed to
deal with this problem; some results appear to be quite promising but there is
no obvious superior method. In this paper, we consider anomaly detection
particular to the Bitcoin transaction network. Our goal is to detect which
users and transactions are the most suspicious; in this case, anomalous
behavior is a proxy for suspicious behavior. To this end, we use three
unsupervised learning methods including k-means clustering, Mahalanobis
distance, and Unsupervised Support Vector Machine (SVM) on two graphs generated
by the Bitcoin transaction network: one graph has users as nodes, and the other
has transactions as nodes.


title: Anomaly Detection in the Bitcoin System - A Network Perspective

abstract:
  The problem of anomaly detection has been studied for a long time, and many
Network Analysis techniques have been proposed as solutions. Although some
results appear to be quite promising, no method is clearly to be superior to
the rest. In this paper, we particularly consider anomaly detection in the
Bitcoin transaction network. Our goal is to detect which users and transactions
are the most suspicious; in this case, anomalous behavior is a proxy for
suspicious behavior. To this end, we use the laws of power degree and
densification and local outlier factor (LOF) method (which is proceeded by
k-means clustering method) on two graphs generated by the Bitcoin transaction
network: one graph has users as nodes, and the other has transactions as nodes.
  We remark that the methods used here can be applied to any type of setting
with an inherent graph structure, including, but not limited to, computer
networks, telecommunications networks, auction networks, security networks,
social networks, Web networks, or any financial networks. We use the Bitcoin
transaction network in this paper due to the availability, size, and
attractiveness of the data set.


title:
Multiplicity free gradings on semisimple Lie and Jordan algebras and
  skew root

abstract:
  A $G$-grading on an algebra is called multiplicity free if each homogeneous
component of the grading is 1-dimensional, where $G$ is an abelian group. We
introduce skew root systems of Lie type and skew root systems of Jordan type
respectively, and use them to construct multiplicity free gradings on
semisimple Lie algebras and on semisimple Jordan algebras respectively. Under
certain conditions the corresponding Lie (resp. Jordan) algebras are simple.
Three families of skew root systems of Lie type (resp. of Jordan type) are
constructed and the corresponding Lie (resp. Jordan) algebras are identified.
This is a new approach to study abelian group gradings on Lie and Jordan
algebras.


title:
Potentials of a family of arrangements of hyperplanes and elementary
  subarrangements

abstract:
  We consider the Frobenius algebra of functions on the critical set of the
master function of a weighted arrangement of hyperplanes in $\C^k$ with normal
crossings. We construct two potential functions (of first and second kind) of
variables labeled by hyperplanes of the arrangement and prove that the matrix
coefficients of the Grothendieck residue bilinear form on the algebra are given
by the $2k$-th derivatives of the potential function of first kind and the
matrix coefficients of the multiplication operators on the algebra are given by
the $(2k+1)$-st derivatives of the potential function of second kind. Thus the
two potentials completely determine the Frobenius algebra. The presence of
these potentials is a manifestation of a Frobenius like structure similar to
the Frobenius manifold structure.
  We introduce the notion of an elementary subarrangement of an arrangement
with normal crossings. It turns out that our potential functions are local in
the sense that the potential functions are sums of contributions from
elementary subarrangements of the given arrangement. This is a new phenomenon
of locality of the Grothendieck residue bilinear form and multiplication on the
algebra.
  It is known that this Frobenius algebra of functions on the critical set is
isomorphic to the Bethe algebra of this arrangement. (That Bethe algebra is an
analog of the Bethe algebras in the theory of quantum integrable models.) Thus
our potential functions describe that Bethe algebra too.


title: Stringy horizons and generalized FZZ duality in perturbation theory

abstract:
  We study scattering amplitudes in two-dimensional string theory on a black
hole bakground. We start with a simple derivation of the
Fateev-Zamolodchikov-Zamolodchikov (FZZ) duality, which associates correlation
functions of the sine-Liouville integrable model on the Riemann sphere to
tree-level string amplitudes on the Euclidean two-dimensional black hole. This
derivation of FZZ duality is based on perturbation theory, and it relies on a
trick originally due to Fateev, which involves duality relations between
different Selberg type integrals. This enables us to rewrite the correlation
functions of sine-Liouville theory in terms of a special set of correlators in
the gauged Wess-Zumino-Witten (WZW) theory, and use this to perform further
consistency checks of the recently conjectured Generalized FZZ (GFZZ) duality.
In particular, we prove that n-point correlation functions in sine-Liouville
theory involving n-2 winding modes actually coincide with the correlation
functions in the SL(2,R)/U(1) gauged WZW model that include n-2 oscillator
operators of the type described by Giveon, Itzhaki and Kutasov in reference
arXiv:1603.05822. This proves the GFZZ duality for the case of tree level
maximally winding violating n-point amplitudes with arbitrary $n$. We also
comment on the connection between GFZZ and other marginal deformations
previously considered in the literature.


title:
New method of averaging diffeomorphisms based on Jacobian determinant
  and curl vector

abstract:
  Averaging diffeomorphisms is a challenging problem, and it has great
applications in areas like medical image atlases. The simple Euclidean average
can neither guarantee the averaged transformation is a diffeomorphism, nor get
reasonable result when there is a local rotation. The goal of this paper is to
propose a new approach to averaging diffeomorphisms based on the Jacobian
determinant and the curl vector of the diffeomorphisms. Instead of averaging
the diffeomorphisms directly, we average the Jacobian determinants and the curl
vectors, and then construct a diffeomorphism based on the averaged Jacobian
determinant and averaged curl vector as the average of diffeomorphisms.
Numerical examples with convincible results are presented to demonstrate the
method.


title: A Pragmatic Non-Blocking Concurrent Directed Acyclic Graph

abstract:
  In this paper, we have developed two algorithms for maintaining acyclicity in
a concurrent directed graph. The first algorithm is based on a wait-free
reachability query and the second one is based on partial snapshot-based
obstruction-free reachability query. Interestingly, we are able to achieve the
acyclic property in the dynamic setting without the need of helping using
descriptors by other threads or clean double collect mechanism. We present a
proof to show that the graph remains acyclic at all times in the concurrent
setting. We also prove that the acyclic graph data-structure operations are
linearizable. We implement both the algorithms in C++ and test through a number
of micro-benchmarks. Our experimental results show an average of 7x improvement
over the sequential and global lock implementation.


title:
Algebra of Kodaira-Spencer Gravity and Deformation of Calabi-Yau
  Manifold

abstract:
  We study the algebraic structure of the configuration space of the
Kodaira-Spencer gravity theory on a Calabi-Yau threefold. We then investigate
the deformation problem of the Kodaira-Spencer gravity at the classical level
using the algebraic tools obtained here.


title: Linguistically Regularized LSTMs for Sentiment Classification

abstract:
  Sentiment understanding has been a long-term goal of AI in the past decades.
This paper deals with sentence-level sentiment classification. Though a variety
of neural network models have been proposed very recently, however, previous
models either depend on expensive phrase-level annotation, whose performance
drops substantially when trained with only sentence-level annotation; or do not
fully employ linguistic resources (e.g., sentiment lexicons, negation words,
intensity words), thus not being able to produce linguistically coherent
representations. In this paper, we propose simple models trained with
sentence-level annotation, but also attempt to generating linguistically
coherent representations by employing regularizers that model the linguistic
role of sentiment lexicons, negation words, and intensity words. Results show
that our models are effective to capture the sentiment shifting effect of
sentiment, negation, and intensity words, while still obtain competitive
results without sacrificing the models' simplicity.


title:
Auxiliary variables for nonlinear equations with softly broken
  symmetries

abstract:
  General methods of solving equations deal with solving N equations in N
variables and the solutions are usually a set of discrete values. However, for
problems with a softly broken symmetry these methods often first find a point
which would be a solution if the symmetry were exact, and is thus an
approximate solution. After this, the solver needs to move in the direction of
the symmetry to find the actual solution, but that can be very difficult if
this direction is not a straight line in the space of variables. The solution
can often be found much more quickly by adding the generators of the softly
broken symmetry as auxiliary variables. This makes the number of variables more
than the equations and hence there will be a family of solutions, any one of
which would be acceptable. In this paper we present a procedure for finding
solutions in this case, and apply it to several simple examples and an
important problem in the physics of false vacuum decay. We also provide a
Mathematica package that implements Powell's hybrid method with the
generalization to allow more variables than equations.


title: Nuclear Fusion in Laser-Driven Counter-Streaming Collisionless Plasmas

abstract:
  Nuclear fusion reactions are the most important processes in nature to power
stars and produce new elements, and lie at the center of the understanding of
nucleosynthesis in the universe. It is critically important to study the
reactions in full plasma environments that are close to true astrophysical
conditions. By using laser-driven counter-streaming collisionless plasmas, we
studied the fusion D$+$D$\rightarrow n +^3$He in a Gamow-like window around 27
keV. The results show that astrophysical nuclear reaction yield can be
modulated significantly by the self-generated electromagnetic fields and the
collective motion of the plasma. This plasma-version mini-collider may provide
a novel tool for studies of astrophysics-interested nuclear reactions in plasma
with tunable energies in earth-based laboratories.


title:
Shared information between residues is sufficient to detect pair-wise
  epistasis in a protein

abstract:
  In a comment on our manuscript "Strong selection significantly increases
epistatic interactions in the long-term evolution of a protein", Dr. Crona
challenges our assertion that shared entropy (that is, information) between two
residues implies epistasis between those residues, by constructing an explicit
example of three loci (say A, B, and C), where A and B are epistatically linked
(leading to shared entropy between A and B), and A and C also depend
epistatically (leading to shared entropy between A and C), so that loci B and C
are correlated (share entropy).


title:
A birational embedding of an algebraic curve into a projective plane
  with two Galois points

abstract:
  A criterion for the existence of a birational embedding of an algebraic curve
into a projective plane with two Galois points is presented. Several novel
examples of plane curves with two inner Galois points as an application are
described.


title:
Multilingual Knowledge Graph Embeddings for Cross-lingual Knowledge
  Alignment

abstract:
  Many recent works have demonstrated the benefits of knowledge graph
embeddings in completing monolingual knowledge graphs. Inasmuch as related
knowledge bases are built in several different languages, achieving
cross-lingual knowledge alignment will help people in constructing a coherent
knowledge base, and assist machines in dealing with different expressions of
entity relationships across diverse human languages. Unfortunately, achieving
this highly desirable crosslingual alignment by human labor is very costly and
errorprone. Thus, we propose MTransE, a translation-based model for
multilingual knowledge graph embeddings, to provide a simple and automated
solution. By encoding entities and relations of each language in a separated
embedding space, MTransE provides transitions for each embedding vector to its
cross-lingual counterparts in other spaces, while preserving the
functionalities of monolingual embeddings. We deploy three different techniques
to represent cross-lingual transitions, namely axis calibration, translation
vectors, and linear transformations, and derive five variants for MTransE using
different loss functions. Our models can be trained on partially aligned
graphs, where just a small portion of triples are aligned with their
cross-lingual counterparts. The experiments on cross-lingual entity matching
and triple-wise alignment verification show promising results, with some
variants consistently outperforming others on different tasks. We also explore
how MTransE preserves the key properties of its monolingual counterpart TransE.


title:
Convergence of Discrete Exterior Calculus Approximations for Poisson
  Problems

abstract:
  Discrete exterior calculus (DEC) is a framework for constructing discrete
versions of exterior differential calculus objects, and is widely used in
computer graphics, computational topology, and discretizations of the
Hodge-Laplace operator and other related partial differential equations.
However, a rigorous convergence analysis of DEC has always been lacking; as far
as we are aware, the only convergence proof of DEC so far appeared is for the
scalar Poisson problem in two dimensions, and it is based on reinterpreting the
discretization as a finite element method. Moreover, even in two dimensions,
there have been some puzzling numerical experiments reported in the literature,
apparently suggesting that there is convergence without consistency. In this
paper, we develop a general independent framework for analyzing issues such as
convergence of DEC without relying on theories of other discretization methods,
and demonstrate its usefulness by establishing convergence results for DEC
beyond the Poisson problem in two dimensions. Namely, we prove that DEC
solutions to the scalar Poisson problem in arbitrary dimensions converge
pointwise to the exact solution at least linearly with respect to the mesh
size. We illustrate the findings by various numerical experiments, which show
that the convergence is in fact of second order when the solution is
sufficiently regular. The problems of explaining the second order convergence,
and of proving convergence for general p-forms remain open.


title: Lorentz breaking terms from Einstein gravity

abstract:
  We construct an action which is invariant under the foliation preserving
diffeomorphism from the Einstein Hilbert action. Starting from the Einstein
Hilbert action, we introduce the gauge invariance under the anisotropic
rescaling by using the St\"uckelberg method. We then introduce the gauge field
corresponds to the anisotropic rescaling, and the St\"uckelberg field turns out
to be the Nambu-Goldstone boson. The Nambu-Goldstone boson, however, is not
completely eaten by the massive gauge field and the Nambu-Goldstone boson can
be integrated out from the action. Then the resultant action is a
Horava-Lifshitz type action which contains $R^3$ term.


title: Inflationary Dynamics Reconstruction via Inverse-Scattering Theory

abstract:
  The evolution of inflationary fluctuations can be recast as an inverse
scattering problem. In this context, we employ the Gel'fand-Levitan method from
inverse-scattering theory to reconstruct the evolution of both the inflaton
field freeze-out horizon and the Hubble parameter during inflation. We
demonstrate this reconstruction procedure numerically for a scenario of
slow-roll inflation, as well as for a scenario which temporarily departs from
slow-roll. The field freeze-out horizon is reconstructed from the accessible
primordial scalar power spectrum alone, while the reconstruction of the Hubble
parameter requires additional information from the tensor power spectrum. We
briefly discuss the application of this technique to more realistic cases
incorporating estimates of the primordial power spectra over limited ranges of
scales and with specified uncertainties.


title:
Optimal control of a linearized continuum model for re-entrant
  manufacturing production systems

abstract:
  A re-entrant manufacturing system producing a large number of items and
involving many steps can be approximately modeled by a hyperbolic partial
differential equation (PDE) according to mass conservation law with respect to
a continuous density of items on a production process. The mathematic model is
a typical nonlinear and nonlocal PDE and the cycle time depends nonlinearly on
the work in progress. However, the nonlinearity brings mathematic and
engineering difficulties in practical application. In this work, we address the
optimal control based on the linearized system model and in order to improve
the model and control accuracy, a modified system model taking into account the
re-entrant degree of the product is utilized to reflect characteristics of
small-scale and large-scale multiple re-entrant manufacturing systems. In this
work, we solve the optimal output reference tracking problem through
combination of variation approach and state feedback internal model control
(IMC) method. Numerical example on optimal boundary influx for step-like demand
rate is presented. In particular, the demand rates are generated by an known
exosystem.


title:
On Smart Query Routing: For Distributed Graph Querying with Decoupled
  Storage

abstract:
  We study online graph queries that retrieve nearby nodes of a query node from
a large network. To answer such queries with high throughput and low latency,
we partition the graph and process the data in parallel across a cluster of
servers. State-of-the-art distributed graph querying systems place each graph
partition on a separate server, where query answering over that partition takes
place. This design has two major disadvantages. First, the router needs to
maintain a fixed routing table. Hence, these systems are less flexible with
respect to query routing, fault tolerance, and graph updates. Second, the graph
data must be partitioned such that the workload across the servers is balanced,
and the inter-machine communication is minimized. In addition, it is required
to update the existing partitions based on workload changes over graph nodes.
However, graph partitioning, online monitoring of workloads, and dynamically
updating the graph partitions are expensive. In this work, we mitigate both
these problems by decoupling graph storage from query processors, and by
developing smart routing strategies that improve the cache locality in query
processors. Since a query processor is no longer assigned any fixed part of the
graph, it is equally capable of handling any request, thus facilitating load
balancing and fault tolerance. On the other hand, due to our smart routing
strategies, query processors can effectively leverage their cache contents,
reducing the overall impact of how the graph is partitioned across storage
servers. A detailed experimental evaluation with several real-world, large
graph datasets demonstrates that our proposed framework, gRouting - even with
simple hash partitioning of the data - achieves up to an order of magnitude
better query throughput compared to existing graph querying systems that employ
expensive graph partitioning and re-partitioning strategies.


title:
Topology of configuration space of the mean-field phi^4 model by Morse
  theory

abstract:
  In this paper we present the study of the topology of the equipotential
hypersurfaces of configuration space of the mean-field $\phi^4$ model with a
$\mathbb{Z}_2$ symmetry. Our purpose is discovering, if any, the relation
between the second-order $\mathbb{Z}_2$-symmetry breaking phase transition and
the geometric entities mentioned above. The mean-field interaction allows us to
solve analytically either the thermodynamic in the canonical ensemble or the
topology by means of Morse theory. We have analyzed the results at the light of
two theorems on sufficiency conditions for symmetry breaking phase transitions
recently proven. This study makes part of a research line based on the general
framework of geometric-topological approach to Hamiltonian chaos and critical
phenomena.


title: Norm approximation for many-body quantum dynamics and Bogoliubov theory

abstract:
  We review some recent results on the norm approximation to the Schr\"odinger
dynamics. We consider $N$ bosons in $\mathbb{R}^3$ with an interaction
potential of the form $N^{3\beta-1}w(N^{\beta}(x-y))$ with $0\le \beta<1/2$,
and show that in the large $N$ limit, the fluctuations around the condensate
can be effectively described using Bogoliubov approximation.


title: Primitive forms for Gepner singularities

abstract:
  We provide a construction of Saito primitive forms for Gepner singularity by
studying the relation between Saito primitive forms for Gepner singularities
and primitive forms for singularities of the form $F_{k,n}=\sum_{i=1}^n x_i^k$
invariant under the natural $S_n$-action.


title: Parametric resonance of magnetization excited by electric field

abstract:
  Manipulation of magnetization by electric field is a central goal of
spintronics because it enables energy-efficient operation of spin-based
devices. Spin wave devices are promising candidates for low-power information
processing but a method for energy-efficient excitation of short-wavelength
spin waves has been lacking. Here we show that spin waves in nanoscale magnetic
tunnel junctions can be generated via parametric resonance induced by electric
field. Parametric excitation of magnetization is a versatile method of
short-wavelength spin wave generation, and thus our results pave the way
towards energy-efficient nanomagnonic devices.


title: Deformations and Rigidity of $\ell$-adic Sheaves

abstract:
  Let $X$ be a smooth connected projective algebraic curve over an
algebraically closed field, and let $S$ be a finite nonempty closed subset in
$X$. We study deformations of $\overline{\mathbb F}_\ell$-sheaves. The
universal deformation space is a formal scheme. Its generic fiber has a rigid
analytic space structure. By studying this rigid analytic space, we prove a
conjecture of Katz which says that if a lisse $\overline{\mathbb Q}_\ell$-sheaf
$\mathcal F$ on $X-S$ is irreducible and rigid, then we have $\mathrm{dim}\,
H^1(X,j_\ast\mathcal End(\mathcal F))=2g$, where $j:X-S\to X$ is the open
immersion, and $g$ is the genus of $X$.


title:
Residual Information of Previous Decision Affects Evidence Accumulation
  in Current Decision

abstract:
  Bias in perceptual decisions comes to pass when the advance knowledge
colludes with the current sensory evidence in support of the final choice. The
literature on decision making suggests two main hypotheses to account for this
kind of bias: internal bias signals are derived from (a) the residual of motor
response-related signals, and (b) the sensory information residues of the
decisions that we made in the past. Beside these hypotheses, a credible
hypothesis proposed by this study to explain the cause of decision biasing,
suggests that the decision-related neuron can make use of the residual
information of the previous decision for the current decision. We demonstrate
the validity of this assumption, first by performing behavioral experiments
based on the two-alternative forced-choice (TAFC) discrimination of motion
direction paradigms and then, we modified the pure drift-diffusion model (DDM)
based on accumulation to the bound mechanism to account for the sequential
effect. In both cases, the trace of the previous trial influences the current
decision. Results indicate that the probability of being correct in a current
decision increases if it is in line with the previously made decision. Also,
the model that keeps the previous decision information provides a better fit to
the behavioral data. Our findings suggest that the state of a decision variable
which is represented in the activity of decision-related neurons after crossing
the bound (in the previous decision) can accumulate with the decision variable
for the current decision in consecutive trials.


title:
Giftness problem and Staging of Math Education (according to the
  I.S.Rubanov paper "Method of Mathematical induction")

abstract:
  One can notice that quite often difference between so-called "standard
students" and "gifted" ones is not because that first are less smart, but they
have different "orientation", they consider subject as a collections of rules
which should not be broken. The first aim is to overcame this dogmatic point of
view on this subject, and only after that possible to judge a person to be
talented one or not. This is the first stage of math education, the material
needs just to serve it.
  The technology of overcoming this wrong relation to subject is discoursed in
spirit of the I.S.Rubanov paper "Method of Mathematical induction" (see chapter
9, http://www.ams.org/books/mawrld/007/). Giftness problems and staging of math
(and scientific) education are discoursed.


title: Signal Processing with Pulse Trains: An Algebraic Approach- Part I

abstract:
  Recently we have shown that it is possible to represent continuous amplitude,
continuous time, band limited signals with an error as small as desired using
pulse trains via the integrate and fire converter (IFC). The IFC is an ultra
low power converter and processing with pulse trains is compatible with the
trends in the silicon technology for very low supply voltages. This paper
presents the definition of addition in pulse trains created by the IFC using
exclusively timing information, and proofs that it constitutes an Abelian group
in the space of IFC pulse trains. We also show that pulse domain addition
corresponds to pointwise addition of analog signals.


title:
Learning Scene-specific Object Detectors Based on a
  Generative-Discriminative Model with Minimal Supervision

abstract:
  One object class may show large variations due to diverse illuminations,
backgrounds and camera viewpoints. Traditional object detection methods often
perform worse under unconstrained video environments. To address this problem,
many modern approaches model deep hierarchical appearance representations for
object detection. Most of these methods require a timeconsuming training
process on large manual labelling sample set. In this paper, the proposed
framework takes a remarkably different direction to resolve the multi-scene
detection problem in a bottom-up fashion. First, a scene-specific objector is
obtained from a fully autonomous learning process triggered by marking several
bounding boxes around the object in the first video frame via a mouse. Here the
human labeled training data or a generic detector are not needed. Second, this
learning process is conveniently replicated many times in different
surveillance scenes and results in particular detectors under various camera
viewpoints. Thus, the proposed framework can be employed in multi-scene object
detection applications with minimal supervision. Obviously, the initial
scene-specific detector, initialized by several bounding boxes, exhibits poor
detection performance and is difficult to improve with traditional online
learning algorithm. Consequently, we propose Generative-Discriminative model to
partition detection response space and assign each partition an individual
descriptor that progressively achieves high classification accuracy. A novel
online gradual optimized process is proposed to optimize the
Generative-Discriminative model and focus on the hard samples.Experimental
results on six video datasets show our approach achieves comparable performance
to robust supervised methods, and outperforms the state of the art
self-learning methods under varying imaging conditions.


title: An Introduction to MM Algorithms for Machine Learning and Statistical

abstract:
  MM (majorization--minimization) algorithms are an increasingly popular tool
for solving optimization problems in machine learning and statistical
estimation. This article introduces the MM algorithm framework in general and
via three popular example applications: Gaussian mixture regressions,
multinomial logistic regressions, and support vector machines. Specific
algorithms for the three examples are derived and numerical demonstrations are
presented. Theoretical and practical aspects of MM algorithm design are
discussed.


title: Signal Processing with Pulse Trains: An Algebraic Approach- Part II

abstract:
  The integrate and fire converter (IFC) enables an alternative to digital
signal processing. IFC converts analog signal voltages into time between pulses
and it is possible to reconstruct the analog signal from the IFC pulses with an
error as small as required. In this paper, we present the definition of
multiplication in pulse trains created by the IFC based on time domain
operations and prove that it constitutes an Abelian group in the space of IFC
pulse trains. We also show that pulse domain multiplication corresponds to
pointwise multiplication of analog signals. It is further proved that pulse
domain multiplication is distributive over pulse domain addition and hence it
forms a field in the space of IFC pulse trains, which is an important property
for linear signal processing.


title: User characterization for online social networks

abstract:
  Online social network analysis has attracted great attention with a vast
number of users sharing information and availability of APIs that help to crawl
online social network data. In this paper, we study the research studies that
are helpful for user characterization as online users may not always reveal
their true identity or attributes. We especially focused on user attribute
determination such as gender, age, etc.; user behavior analysis such as motives
for deception; mental models that are indicators of user behavior; user
categorization such as bots vs. humans; and entity matching on different social
networks. We believe our summary of analysis of user characterization will
provide important insights to researchers and better services to online users.


title: Observational properties of rigidly rotating dust configurations

abstract:
  We study the observational properties of a class of exact solutions of
Einstein's field equations describing stationary, axially symmetric, rigidly
rotating dust (i.e. non interacting particles). We ask the question whether
such solutions can describe astrophysical rotating dark matter clouds near the
center of galaxies and we probe the possibility that they may constitute an
alternative to supermassive black holes at the center of galaxies. We show that
light emission from accretion disks made of ordinary baryonic matter in this
space-time has several differences with respect to the emission of light from
similar accretion disks around black holes. The shape of the iron K$\alpha$
line in the reflection spectrum of accretion disks can potentially distinguish
this class of solution from the Kerr metric, but this may not be possible with
current X-ray missions.


title:
Polyakov line actions from SU(3) lattice gauge theory with dynamical
  fermions via relative weights

abstract:
  We extract an effective Polyakov line action from an underlying SU(3) lattice
gauge theory with dynamical fermions via the relative weights method. The
center-symmetry breaking terms in the effective theory are fit to a form
suggested by effective action of heavy-dense quarks, and the effective action
is solved at finite chemical potential by a mean field approach. We show
results for a small sample of lattice couplings, lattice actions, and lattice
extensions in the time direction. We find in some instances that the long-range
couplings in the effective action are very important to the phase structure,
and that these couplings are responsible for long-lived metastable states in
the effective theory. Only one of these states corresponds to the underlying
lattice gauge theory.


title: On approximations via convolution-defined mixture models

abstract:
  An often-cited fact regarding mixing or mixture distributions is that their
density functions are able to approximate the density function of any unknown
distribution to arbitrary degrees of accuracy, provided that the mixing or
mixture distribution is sufficiently complex. This fact is often not made
concrete. We investigate and review theorems that provide approximation bounds
for mixing distributions. Connections between the approximation bounds of
mixing distributions and estimation bounds for the maximum likelihood estimator
of finite mixtures of location- scale distributions are reviewed.


title:
On the structure of Selmer and Shafarevich-Tate groups of higher weight
  modular forms

abstract:
  Under a non-torsion assumption on Heegner points, results of Kolyvagin
describe the structure of Shafarevich-Tate groups of elliptic curves. In this
paper we prove analogous results for ($p$-primary) Shafarevich-Tate groups
associated with higher weight modular forms over imaginary quadratic fields
satisfying a "Heegner hypothesis". More precisely, we show that the structure
of Shafarevich-Tate groups is controlled by cohomology classes built out of
Nekov\'a\v{r}'s Heegner cycles on Kuga-Sato varieties. As an application of our
main theorem, we improve on a result of Besser giving a bound on the order of
these groups. As a second contribution, we prove a result on the structure of
($p$-primary) Selmer groups of modular forms in the sense of Bloch--Kato.


title: X-ray burst induced spectral variability in 4U 1728-34

abstract:
  Aims. INTEGRAL has been monitoring the Galactic center region for more than a
decade. Over this time INTEGRAL has detected hundreds of type-I X-ray bursts
from the neutron star low-mass X-ray binary 4U 1728-34, a.k.a. "the slow
burster". Our aim is to study the connection between the persistent X-ray
spectra and the X-ray burst spectra in a broad spectral range. Methods. We
performed spectral modeling of the persistent emission and the X-ray burst
emission of 4U 1728-34 using data from the INTEGRAL JEM-X and IBIS/ISGRI
instruments. Results. We constructed a hardness intensity diagram to track
spectral state variations. In the soft state the energy spectra are
characterized by two thermal components - likely from the accretion disc and
the boundary/spreading layer - together with a weak hard X-ray tail that we
detect in 4U 1728-34 for the first time in the 40 to 80 keV range. In the hard
state the source is detected up to 200 keV and the spectrum can be described by
a thermal Comptonization model plus an additional component: either a powerlaw
tail or reflection. By stacking 123 X-ray bursts in the hard state, we detect
emission up to 80 keV during the X-ray bursts. We find that during the bursts
the emission above 40 keV decreases by a factor of about three with respect to
the persistent emission level. Conclusions. Our results suggest that the
enhanced X-ray burst emission changes the spectral properties of the accretion
disc in the hard state. The likely cause is an X-ray burst induced cooling of
the electrons in the inner hot flow near the neutron star.


title: A Review on Algorithms for Constraint-based Causal Discovery

abstract:
  Causal discovery studies the problem of mining causal relationships between
variables from data, which is of primary interest in science. During the past
decades, significant amount of progresses have been made toward this
fundamental data mining paradigm. Recent years, as the availability of abundant
large-sized and complex observational data, the constrain-based approaches have
gradually attracted a lot of interest and have been widely applied to many
diverse real-world problems due to the fast running speed and easy generalizing
to the problem of causal insufficiency. In this paper, we aim to review the
constraint-based causal discovery algorithms. Firstly, we discuss the learning
paradigm of the constraint-based approaches. Secondly and primarily, the
state-of-the-art constraint-based casual inference algorithms are surveyed with
the detailed analysis. Thirdly, several related open-source software packages
and benchmark data repositories are briefly summarized. As a conclusion, some
open problems in constraint-based causal discovery are outlined for future
research.


title:
On the one-way specification property and large deviations for
  non-transitive systems

abstract:
  We introduce a weaker form of the specification property, called "one-way
specification property", and give several examples of non-transitive systems
satisfying this property. As an application, we show that the
$(-\beta)$-transformation satisfies a level-2 large deviation principle with
the Lebesgue measure and the rate function is the free energy under the
condition that $\beta>1$ is a Yrrap number, that is, the orbit of $1$ under the
$(-\beta)$-transformation is eventually periodic.


title:
Kernel regression, minimax rates and effective dimensionality: beyond
  the regular case

abstract:
  We investigate if kernel regularization methods can achieve minimax
convergence rates over a source condition regularity assumption for the target
function. These questions have been considered in past literature, but only
under specific assumptions about the decay, typically polynomial, of the
spectrum of the the kernel mapping covariance operator. In the perspective of
distribution-free results, we investigate this issue under much weaker
assumption on the eigenvalue decay, allowing for more complex behavior that can
reflect different structure of the data at different scales.


title: Many Faces of Boussinesq Approximations

abstract:
  The \emph{equations of Boussinesq approximation} (EBA) for an incompressible
and inhomogeneous in density fluid are analyzed from a viewpoint of the
asymptotic theory. A systematic scaling shows that there is an infinite number
of related asymptotic models. We have divided them into three classes: `poor',
`reasonable' and `good' Boussinesq approximations. Each model can be
characterized by two parameters $q$ and $k$, where $q =1, 2, 3, \dots$ and
$k=0, \pm 1, \pm 2,\dots$. Parameter $q$ is related to the `quality' of
approximation, while $k$ gives us an infinite set of possible scales of
velocity, time, viscosity, \emph{etc.} Increasing $q$ improves the quality of a
model, but narrows the limits of its applicability. Parameter $k$ allows us to
vary the scales of time, velocity and viscosity and gives us the possibility to
consider any initial and boundary conditions. In general, we discover and
classify a rich variety of possibilities and restrictions, which are hidden
behind the routine use of the Boussinesq approximation. The paper is devoted to
the multiplicity of scalings and related restrictions. We do not study any
particular solutions and particular failures of EBA.


title: Dual Teaching: A Practical Semi-supervised Wrapper Method

abstract:
  Semi-supervised wrapper methods are concerned with building effective
supervised classifiers from partially labeled data. Though previous works have
succeeded in some fields, it is still difficult to apply semi-supervised
wrapper methods to practice because the assumptions those methods rely on tend
to be unrealistic in practice. For practical use, this paper proposes a novel
semi-supervised wrapper method, Dual Teaching, whose assumptions are easy to
set up. Dual Teaching adopts two external classifiers to estimate the false
positives and false negatives of the base learner. Only if the recall of every
external classifier is greater than zero and the sum of the precision is
greater than one, Dual Teaching will train a base learner from partially
labeled data as effectively as the fully-labeled-data-trained classifier. The
effectiveness of Dual Teaching is proved in both theory and practice.


title:
Efficient Proofs of Retrievability with Public Verifiability for Dynamic
  Cloud Storage

abstract:
  Cloud service providers offer various facilities to their clients. The
clients with limited resources opt for some of these facilities. They can
outsource their bulk data to the cloud server. The cloud server maintains these
data in lieu of monetary benefits. However, a malicious cloud server might
delete some of these data to save some space and offer this extra amount of
storage to another client. Therefore, the client might not retrieve her file
(or some portions of it) as often as needed. Proofs of retrievability (POR)
provide an assurance to the client that the server is actually storing all of
her data appropriately and they can be retrieved at any point of time. In a
dynamic POR scheme, the client can update her data after she uploads them to
the cloud server. Moreover, in publicly verifiable POR schemes, the client can
delegate her auditing task to some third party specialized for this purpose. In
this work, we exploit the homomorphic hashing technique to design a publicly
verifiable dynamic POR scheme that is more efficient (in terms of bandwidth
required between the client and the server) than the "state-of-the-art"
publicly verifiable dynamic POR scheme. We also analyze security and
performance of our scheme.


title:
The Exceptional Flare of Mrk 501 in 2014: Combined Observations with
  H.E.S.S. and FACT

abstract:
  The BL Lac type object Mrk 501 was observed at very high energies (E > 100
GeV) in 2014 with the upgraded H.E.S.S. (High Energy Stereoscopic System) phase
2 array. The data collected with the central 28m telescope allow for a broader
energy range extending to lower energies when compared to the one obtained with
the four small telescopes alone. A strong flaring event with a flux level
comparable to the 1997 historical maximum has been detected as a consequence of
target of opportunity observations triggered by alerts from the FACT
collaboration. The First G-APD Cherenkov Telescope (FACT) is continuously
monitoring bright blazars at TeV energies providing important pre- and
post-flare information. For the first time, the data and lightcurves from
H.E.S.S. and FACT are compared. These contemporaneous observations allow for a
better characterization of the source emission. In a multiwavelength context,
more precise correlation studies between VHE and lower energies are possible
thanks to the dense sampling of the FACT observations. The hard intrinsic
spectrum detected by H.E.S.S. during the flare allows the derivation of strong
constraints on the scale of Lorentz invariance violation via the non-detection
of EBL opacity modifications and from time-of-flight studies.


title:
Simultaneous longitudinal and transverse oscillation in an active
  filament

abstract:
  We report on the co-existence of longitudinal and transverse oscillations in
an active filament. On March 15$^{th}$ 2013, a M1.1 class flare was observed in
the active region AR 11692. A CME was found to be associated with the flare.
{The CME generated a shock wave that triggered the oscillations in a nearby
filament}, situated at the south-west of the active region as observed from
National Solar Observatory (NSO)\textit{Global Oscillation Network Group}(GONG)
H$\alpha$ images. In this work we report the longitudinal oscillations in the
two ends of the filament, co-existing with the transverse oscillations. We
propose a scenario in which {an} incoming shock wave hits the filament
obliquely and triggers both longitudinal and transverse oscillations. Using the
observed parameters, we estimate the lower limit of the magnetic field
strength. We use simple pendulum model with gravity as the restoring force to
estimate the radius of curvature. We also calculate the mass accretion rate
which causes the filament motions to damp quite fast.


title: Homogeneous G\"odel-type solutions in hybrid metric-Palatini gravity

abstract:
  [Abridged] If gravitation is to be described by a hybrid metric-Palatini
$f(\mathcal{R})$ gravity theory there are a number of issues that ought to be
examined in its context, including the question as to whether its equations
allow homogeneous G\"odel-type solutions, which necessarily leads to violation
of causality. Here, to look further into the potentialities and difficulties of
$f(\mathcal{R})$ theories, we examine whether they admit G\"odel-type solutions
for well-motivated matter source. We first show that under certain conditions
on the matter sources the problem of finding out space-time homogeneous
solutions in $f(\mathcal{R})$ theories reduces to the problem of determining
solutions of Einstein's field equations with a cosmological constant. Employing
this far-reaching result, we determine a general G\"odel-type whose matter
source is a combination of a scalar with an electromagnetic field plus a
perfect fluid. This general G\"odel-type solution contains special solutions in
which the essential parameter $m^2$ can be $m^{2} > 0$, $m=0$, and $m^{2} < 0$,
covering thus all classes of homogeneous G\"odel-type spacetimes. This general
solution also contains all previously known solution as special cases. The bare
existence of these G\"odel-type solutions makes apparent that hybrid
metric-Palatini gravity does not remedy causal anomaly in the form of closed
timelike curves that are permitted in general relativity.


title: Squeezed states of light and their applications in laser interferometers

abstract:
  According to quantum theory the interactions between physical systems are
quantized. As a direct consequence, measurement sensitivities are fundamentally
limited by quantization noise, or just `quantum noise' in short. Furthermore,
Heisenberg's Uncertainty Principle demands measurement back-action for some
observables of a system if they are measured repeatedly. In both respects,
squeezed states are of high interest since they show a `squeezed' uncertainty,
which can be used to improve the sensitivity of measurement devices beyond the
usual quantum noise limits including those impacted by quantum back-action
noise. Squeezed states of light can be produced with nonlinear optics, and a
large variety of proof-of-principle experiments were performed in past decades.
As an actual application, squeezed light has now been used for several years to
improve the measurement sensitivity of GEO600 -- a laser interferometer built
for the detection of gravitational waves. Given this success, squeezed light is
likely to significantly contribute to the new field of gravitational-wave
astronomy. This Review revisits the concept of squeezed states and two-mode
squeezed states of light, with a focus on experimental observations. The
distinct properties of squeezed states displayed in quadrature phase-space as
well as in the photon number representation are described. The role of the
light's quantum noise in laser interferometers is summarized and the actual
application of squeezed states in these measurement devices is reviewed.


title:
Comparison of algorithms for solving the sign problem in the O(3) model
  in 1+1 dimensions at finite chemical potential

abstract:
  We study three possible ways to circumvent the sign problem in the O(3)
nonlinear sigma model in 1+1 dimensions. We compare the results of the worm
algorithm to complex Langevin and multiparameter reweighting. Using the worm
algorithm, the thermodynamics of the model is investigated, and continuum
results are shown for the pressure at different $\mu/T$ values in the range
$0-4$. By performing $T=0$ simulations using the worm algorithm the Silver
Blaze phenomenon is reproduced. Regarding the complex Langevin, we test various
implementations of discretizing the complex Langevin equation. We found that
the exponentialized Euler discretization of the Langevin equation gives wrong
results for the action and the density at low $T/m$. By performing continuum
extrapolation we found that this discrepancy does not disappear and depends
slightly on temperature. The discretization with spherical coordinates perform
similarly at low $\mu/T$, but goes wrong also at some higher temperatures at
high $\mu/T$. However, a third discretization that uses a constraining force to
achieve the $\phi^2 = 1$ condition gives correct results for the action, but
wrong results for the density at low $\mu/T$.


title: A Boltzmann approach to mean-field sparse feedback control

abstract:
  We study the synthesis of optimal control policies for large-scale
multi-agent systems. The optimal control design induces a parsimonious control
intervention by means of l-1, sparsity-promoting control penalizations. We
study instantaneous and infinite horizon sparse optimal feedback controllers.
In order to circumvent the dimensionality issues associated to the control of
large-scale agent-based models, we follow a Boltzmann approach. We generate
(sub)optimal controls signals for the kinetic limit of the multi-agent
dynamics, by sampling of the optimal solution of the associated two-agent
dynamics. Numerical experiments assess the performance of the proposed sparse
design.


title: Weak value beyond conditional expectation value of the pointer readings

abstract:
  It is argued that a weak value of an observable is a robust property of a
single pre- and post-selected quantum system rather than a statistical
property. During an infinitesimal time a system with a given weak value affects
other systems as if it were in an eigenstate with eigenvalue equal to the weak
value. This differs significantly from the action of a system pre-selected only
and possessing a numerically equal expectation value. The weak value has a
physical meaning beyond a conditional average of a pointer in the weak
measurement procedure. The difference between the weak value and the
expectation value has been demonstrated on the example of photon polarization.
In addition, the weak values for systems pre- and post-selected in mixed states
are considered.


title: On McDiarmid's inequality for Hamming distance

abstract:
  We improve the rate function of McDiarmid's inequality for Hamming distance.
In particular, applying our result to the separately Lipschitz functions of
independent random variables, we also refine the convergence rate function of
McDiarmid's inequality around a median. Moreover, a non-uniform bound for the
distance between the medians and the mean is also given. We also give some
extensions of McDiarmid's inequalities to the case of nonnegative functionals
of dependent random variables.


title:
A Further Step Towards an Understanding of the Tournament Equilibrium
  Set

abstract:
  We study some problems pertaining to the tournament equilibrium set (TEQ for
short). A tournament $H$ is a TEQ-retentive tournament if there is a tournament
$T$ which has a minimal TEQ-retentive set $R$ such that $T[R]$ is isomorphic to
$H$. We study TEQ-retentive tournaments and achieve many significant results.
In particular, we prove that there are no TEQ-retentive tournaments of size 4,
only 2 non-isomorphic TEQ-retentive tournaments of sizes 5 and 6, respectively,
and 26 non-isomorphic TEQ-retentive tournaments of size 7. For three
tournaments $H_1, H_2$ and $T$, we say $T$ is a $(H_1,H_2)$-TEQ-retentive
tournament if $T$ has two minimal TEQ-retentive sets $R_1$ and $R_2$ such that
$T[R_1]$ and $T[R_2]$ are isomorphic to $H_1$ and $H_2$, respectively. We show
that there are no $(H_1,H_2)$-retentive tournaments for $H_1$ and $H_2$ being
small tournaments. Our results imply that Schwartz's Conjecture holds in all
tournaments of size at most 14. Finally, we study Schwartz's Conjecture in
several classes of tournaments. To achieve these results, we study the relation
between (directed) domination graphs of tournaments and TEQ-retentive sets, and
derive a number of properties on minimal TEQ-retentive sets.


title:
Eigenstate Thermalization and Spontaneous Symmetry Breaking in the
  One-Dimensional Transverse-Field Ising Model with Power-Law Interactions

abstract:
  We study eigenstate thermalization and related signatures of quantum chaos in
the one-dimensional ferromagnetic transverse-field Ising model with power-law
interactions. The presence of long-range interactions allows for a
finite-temperature phase transition despite the one-dimensional geometry of the
model. Unlike previous studies of eigenstate thermalization in non-disordered
systems with finite temperature phase transitions, our model possesses
sufficiently many energy eigenstates below the critical energy density to allow
us to make a definitive statement about the presence of eigenstate
thermalization and chaotic level statistics in the broken-symmetry phase.


title: Riemannian Tensor Completion with Side Information

abstract:
  By restricting the iterate on a nonlinear manifold, the recently proposed
Riemannian optimization methods prove to be both efficient and effective in low
rank tensor completion problems. However, existing methods fail to exploit the
easily accessible side information, due to their format mismatch. Consequently,
there is still room for improvement in such methods. To fill the gap, in this
paper, a novel Riemannian model is proposed to organically integrate the
original model and the side information by overcoming their inconsistency. For
this particular model, an efficient Riemannian conjugate gradient descent
solver is devised based on a new metric that captures the curvature of the
objective.Numerical experiments suggest that our solver is more accurate than
the state-of-the-art without compromising the efficiency.