title:
Projective measurement of energy on an ensemble of qubits with unknown
  frequencies

abstract:
  In projective measurements of energy, a target system is projected to an
eigenstate of the system Hamiltonian, and the measurement outcomes provide the
information of corresponding eigen-energies. Recently, it has been shown that
such a measurement can be in principle realized without detailed knowledge of
the Hamiltonian by using probe qubits. However, in the previous approach for
the energy measurement, the necessary size of the dimension for the probe
increases as we increase the dimension of the target system, and also
individual addresibility of every qubit is required, which may not be possible
for many experimental settings with large systems. Here, we show that a single
probe qubit is sufficient to perform such a projective measurement of energy if
the target system is composed of non-interacting qubits whose resonant
frequencies are unknown. Moreover, our scheme requires only global
manipulations where every qubit is subjected to the same control fields. These
results indicate the feasibility of our energy projection protocols.


title: The Complexity of Shelflisting

abstract:
  Optimal shelflisting invites profit maximization to become sensitive to the
ways in which purchasing decisions are order-dependent. We study the
computational complexity of the corresponding product arrangement problem when
consumers are either rational maximizers, use a satisficing procedure, or apply
successive choice. The complexity results we report are shown to crucially
depend on the size of the top cycle in consumers' preferences over products and
on the direction in which alternatives on the shelf are encountered.


title:
Statistical properties of a free-electron laser revealed by the Hanbury
  Brown and Twiss interferometry

abstract:
  We present a comprehensive experimental analysis of statistical properties of
the self-amplified spontaneous emission (SASE) free-electron laser (FEL) FLASH
at DESY in Hamburg by means of Hanbury Brown and Twiss (HBT) interferometry.
The experiments were performed at the FEL wavelengths of 5.5 nm, 13.4 nm, and
20.8 nm. We determined the 2-nd order intensity correlation function for all
wavelengths and different operation conditions of FLASH. In all experiments a
high degree of spatial coherence (above 50%) was obtained. Our analysis
performed in spatial and spectral domains provided us with the independent
measurements of an average pulse duration of the FEL that were below 60 fs. To
explain complicated behaviour of the 2-nd order intensity correlation function
we developed advanced theoretical model that includes the presence of multiple
beams and external positional jitter of the FEL pulses. By this analysis we
determined that in most experiments several beams were present in radiating
field and in one of the experiments external positional jitter was about 25% of
the beam size. We envision that methods developed in our study will be used
widely for analysis and diagnostics of the FEL radiation.


title:
Check of a new non-perturbative mechanism for elementary fermion mass
  generation

abstract:
  We consider a field theoretical model where a SU(2) fermion doublet,
subjected to non-Abelian gauge interactions, is also coupled to a complex
scalar field doublet via a Yukawa and an irrelevant Wilson-like term. Despite
the presence of these two chiral breaking operators in the Lagrangian, an exact
symmetry acting on fermions and scalars prevents perturbative mass corrections.
In the phase where fermions are massless (Wigner phase) the Yukawa coupling can
be tuned to a critical value at which chiral transformations acting on fermions
only become a symmetry of the theory (up to cutoff effects). In the
Nambu-Goldstone phase of the critical theory a fermion mass term of dynamical
origin is expected to arise in the Ward identities of the purely fermionic
chiral transformations. Such a non-perturbative mechanism of dynamical mass
generation can provide a "natural" (\`a la 't Hooft) alternative to the Higgs
mechanism adopted in the Standard Model. Here we lay down the theoretical
framework necessary to demonstrate the existence of this mechanism by means of
lattice simulations.


title:
Lagrangian submanifolds of the nearly K\"ahler $\mathbb{S}^3 \times
  \mathbb{S}^3$ from minimal surfaces in $\mathbb{S}^3$

abstract:
  We study non-totally geodesic Lagrangian submanifolds of the nearly K\"ahler
$\mathbb{S}^3 \times \mathbb{S}^3$ for which the projection on the first
component is nowhere of maximal rank. We show that this property can be
expressed in terms of the so called angle functions and that such Lagrangian
submanifolds are closely related to minimal surfaces in $\mathbb{S}^3$. Indeed,
starting from an arbitrary minimal surface, we can construct locally a large
family of such Lagrangian immersions, including one exceptional example.


title:
Optimized clothes segmentation to boost gender classification in
  unconstrained scenarios

abstract:
  Several applications require demographic information of ordinary people in
unconstrained scenarios. This is not a trivial task due to significant human
appearance variations. In this work, we introduce trixels for clustering image
regions, enumerating their advantages compared to superpixels. The classical
GrabCut algorithm is later modified to segment trixels instead of pixels in an
unsupervised context. Combining with face detection lead us to a clothes
segmentation approach close to real time. The study uses the challenging Pascal
VOC dataset for segmentation evaluation experiments. A final experiment
analyzes the fusion of clothes features with state-of-the-art gender
classifiers in ClothesDB, revealing a significant performance improvement in
gender classification.


title: Graded Division Algebras over the Field of Real Numbers

abstract:
  We give a full classification, up to equivalence, of finite-dimensional
graded division algebras over the field of real numbers. The grading group is
any abelian group.


title:
Detecting Koszulness and related homological properties from the algebra
  structure of Koszul homology

abstract:
  Let $k$ be a field and $R$ a standard graded $k$-algebra. We denote by
$\operatorname{H}^R$ the homology algebra of the Koszul complex on a minimal
set of generators of the irrelevant ideal of $R$. We discuss the relationship
between the multiplicative structure of $\operatorname{H}^R$ and the property
that $R$ is a Koszul algebra. More generally, we work in the setting of local
rings and we show that certain conditions on the multiplicative structure of
Koszul homology imply strong homological properties, such as existence of
certain Golod homomorphisms, leading to explicit computations of Poincar\'e
series. As an application, we show that the Poincar\'e series of all finitely
generated modules over a stretched Cohen-Macaulay local ring are rational,
sharing a common denominator.


title: Concepts and Criteria for Blind Quantum Source Separation

abstract:
  Blind Source Separation (BSS) is an active domain of Classical Information
Processing. The development of Quantum Information Processing has made possible
the appearance of Blind Quantum Source Separation (BQSS). This article
discusses some consequences of the existence of the entanglement phenomenon,
and of the probabilistic aspect of quantum measurements, upon BQSS solutions.
It focuses on a pair of spins initially separately prepared in a pure state,
and then with an undesired coupling between these spins. An unentanglement
criterion is established for the state of an arbitrary qubit pair, expressed
first with probability amplitudes and secondly with probabilities. It is
stressed that the concept of statistical independence of the sources, widely
used in classical BSS, should be used with care in BQSS, and possibly replaced
by some disentanglement principle. It is shown that the coefficients of the
development of any qubit pair pure state, over the states of the standard
basis, can be expressed with the probabilities of results in the measurements
of well-chosen spin components.


title: Almost sure invariance principle for random piecewise expanding maps

abstract:
  We prove a fiberwise almost sure invariance principle for random piecewise
expanding transformations in one and higher dimensions using recent
developments on martingale techniques.


title:
High-Resolution Structure and Intermolecular Interactions between L-type
  Straight Flagellar Filaments

abstract:
  Bacterial mobility is powered by rotation of helical flagellar filaments
driven by rotary motors. Flagellin isolated from {\it Salmonella Typhimurium}
SJW1660 strain, which differs by a point mutation from the wild-type strain,
assembles into straight filaments in which flagellin monomers are arranged into
left-handed helix. Using small-angle X-ray scattering (SAXS) and osmotic stress
methods, we investigated the high-resolution structure of SJW1660 flagellar
filaments as well as intermolecular forces that govern their assembly into
dense hexagonal bundle. The scattering data were fitted to high-resolution
models, which took into account the atomic structure of the flagellin subunits.
The analysis revealed the exact helical arrangement and the super-helical twist
of the flagellin subunits within the filaments. Under osmotic stress the
filaments formed $2D$ hexagonal bundles. Monte-Carlo simulations and continuum
theories were used to analyze the scattering data from hexagonal arrays,
revealing how bulk modulus, as well as how the deflection length depends on the
applied osmotic stress. Scattering data from aligned flagellar bundles
confirmed the predicated structure-factor scattering peak line-shape.
Quantitative analysis of the measured equation of state of the bundles revealed
the contributions of the electrostatic, hydration, and elastic interactions to
the intermolecular interactions associated with bundling of straight
semi-flexible flagellar filaments.}%1 {Insert Received for publication Date and
in final form Date.


title: On derived Hall numbers for tame quivers

abstract:
  In the present paper we study the derived Hall algebra for the bounded
derived category of the nilpotent representations of a tame quiver over a
finite field. We show that for any three given objects in the bounded derived
category, the associated derived Hall numbers are given by a rational function
in the cardinalities of ground fields.


title:
Confinement, NonAbelian monopoles, and 2D CP(N-1) model on the
  worldsheet of finite-length strings

abstract:
  Quark confinement is proposed to be a dual Meissner effect of nonAbelian
kind. Important hints come from physics of strongly-coupled
infrared-fixed-point theories in N=2 supersymmetric QCD, which turn into
confining vacua under a small relevant perturbation. The quest for the
semiclassical origin of the nonAbelian monopoles, ubiquitous as the infrared
degrees of freedom in supersymmetric gauge theories, motivates us to study the
quantum dynamics of 2D CP(N-1)model defined on a finite-width worldstrip, with
various boundary conditions. The model is found to possess a unique phase
("confinement phase"), independent of the length of the string, showing the
quantum persistence of the nonAbelian monopole.


title:
Ground states of nonlinear fractional Schr\"odinger equation involving
  critical growth

abstract:
  In this paper, we are concerned with the ground state solutions of nonlinear
fractional Schr\"odinger equation involving critical growth. Without
Ambrosetti-Rabinowitz condition and monotonicity condition on the nonlinearity,
we get the existence of ground state solutions of such equation when the
potential $V(x)$ is not a constant and not radial.


title: Subgroups of Quantum Groups

abstract:
  We investigate the notion of a subgroup of a quantum group. We suggest a
general definition, which takes into account the work that has been done for
quantum homogeneous spaces. We further restrict our attention to reductive
subgroups, where some faithful flatness conditions apply. Furthermore, we
proceed with a categorical approach to the problem of finding quantum
subgroups. We translate all existing results into the language of module and
monoidal categories and give another characterization of the notion of a
quantum subgroup.


title: Schwinger pairs production in a soft-wall model

abstract:
  The Schwinger pairs production rate is calculated numerically in the
soft-wall model with the help of a simpler method in determining the
soft-wall's position beyond which probe strings connecting the Schwinger pairs
do not fall into. Behaviours of the production rate in both the upper critical
region and the middle linear part are studied carefully. The latter exhibits
interesting new features un-noted previously. All results are presented in
comparisons with hard-wall models.


title:
Multi-Language Identification Using Convolutional Recurrent Neural
  Network

abstract:
  Language Identification, being an important aspect of Automatic Speaker
Recognition has had many changes and new approaches to ameliorate performance
over the last decade. We compare the performance of using audio spectrum in the
log scale and using Polyphonic sound sequences from raw audio samples to train
the neural network and to classify speech as either English or Spanish. To
achieve this, we use the novel approach of using a Convolutional Recurrent
Neural Network using Long Short Term Memory (LSTM) or a Gated Recurrent Unit
(GRU) for forward propagation of the neural network. Our hypothesis is that the
performance of using polyphonic sound sequence as features and both LSTM and
GRU as the gating mechanisms for the neural network outperform the traditional
MFCC features using a unidirectional Deep Neural Network.


title:
Unravelling the components of a multi-thermal coronal loop using
  magnetohydrodynamic seismology

abstract:
  Coronal loops, constituting the basic building blocks of the active Sun,
serve as primary targets to help understand the mechanisms responsible for
maintaining multi-million Kelvin temperatures in the solar and stellar coronae.
Despite significant advances in observations and theory, our knowledge on the
fundamental properties of these structures is limited. Here, we present
unprecedented observations of accelerating slow magnetoacoustic waves along a
coronal loop that show differential propagation speeds in two distinct
temperature channels, revealing the multi-stranded and multi-thermal nature of
the loop. Utilizing the observed speeds and employing nonlinear force-free
magnetic field extrapolations, we derive the actual temperature variation along
the loop in both channels, and thus are able to resolve two individual
components of the multi-thermal loop for the first time. The obtained positive
temperature gradients indicate uniform heating along the loop, rather than
isolated footpoint heating.


title: Trust-based Secure Routing in Software-defined Vehicular Ad Hoc Networks

abstract:
  With the rising interest of expedient, safe, and high-efficient
transportation, vehicular ad hoc networks (VANETs) have turned into a critical
technology in smart transportation systems. Because of the high mobility of
nodes, VANETs are vulnerable to security attacks. In this paper, we propose a
novel framework of software-defined VANETs with trust management. Specifically,
we separate the forwarding plane in VANETs from the control plane, which is
responsible for the control functionality, such as routing protocols and trust
management in VANETs. Using the on-demand distance vector routing (TAODV)
protocol as an example, we present a routing protocol named software-defined
trust based ad hoc on-demand distance vector routing (SD-TAODV). Simulation
results are presented to show the effectiveness of the proposed
software-defined VANETs with trust management.


title: Anomalous resistivity upturn in epitaxial L21-Co2MnAl films

abstract:
  We report the controllable growth and the intriguing transport behavior of
high-spin-polarization epitaxial L21-Co2MnAl films, which exhibit a
low-temperature (T) resistivity upturn with pronounced T1/2 dependence, close
relevance to structural disorder, and robust independence of magnetic fields.
The resistivity upturn turns out to be qualitatively contradictory to weak
localization, particle-particle channel electron-electron interaction (EEI),
and orbital two-channel Kondo effect, leaving a three-dimensional particle-hole
channel EEI the most likely physical source. Our result highlights a
considerable tunability of the structural and electronic disorder of magnetic
films by varying growth temperature, affording unprecedented insights into the
spin polarization and the resistivity upturn.


title: On super-strong Wilf equivalence classes of permutations

abstract:
  Super-strong (elsewhere referred to as strong) Wilf equivalence is a type of
Wilf equivalence on words that was introduced by Kitaev et al. in 2009. We
provide a necessary and sufficient condition for two permutations in $n$
letters to be super-strongly Wilf equivalent, using distances between letters
within a permutation. Furthermore, we give a characterization of such
equivalence classes via two-colored binary trees. This allows us to prove, in
the case of super-strong Wilf equivalence, the conjecture stated in (Kitaev et
al., 2009) that the cardinality of each Wilf equivalence class is a power of 2.


title:
Development of a Bonner Sphere Neutron Spectrometer from a Commercial
  Neutron Dosimeter

abstract:
  Bonner Spheres have been used widely for the measurement of neutron spectra
with neutron energies ranged from thermal up to at least 20 MeV. A Bonner
Sphere neutron spectrometer (BSS) was developed by extending a Berthold LB 6411
neutron-dose-rate meter. The BSS consists of a $^{3}$He thermal-neutron
detector with integrated electronics, a set of eight polyethylene spherical
shells and two optional lead shells of various sizes. The response matrix of
the BSS was calculated with GEANT4 Monte Carlo simulation. The BSS had a
calibration uncertainty of $\pm 8.6\%$ and a detector background rate of $(1.57
\pm 0.04) \times 10^{-3}$ s$^{-1}$. A spectral unfolding code NSUGA was
developed. The NSUGA code utilizes genetic algorithms and has been shown to
perform well in the absence of a priori information.


title:
Robustness of ergodic properties of nonautonomous piecewise expanding
  maps

abstract:
  Recently, there has been an increasing interest on nonautonomous composition
of perturbed hyperbolic systems: composing perturbations of a given hyperbolic
map $F$ results in statistical behaviour close to that of $F$. We show this
fact in the case of piecewise regular expanding maps. In particular, we impose
conditions on perturbations of this class of maps that include situations
slightly more general than what has been considered so far, and prove that
these are stochastically stable in the usual sense. We then prove that the
evolution of a given distribution of mass under composition of time dependent
perturbations (arbitrarily - rather than randomly - chosen at each step) close
to a given map $F$ remains close to the invariant mass distribution of $F$.
Moreover, for almost every point, Birkhoff averages along trajectories do not
fluctuate wildly. This result complements recent results on memory loss for
nonautonomous dynamical systems.


title:
Machine to Machine (M2M) Communications in Virtualized Vehicular Ad Hoc
  Networks

abstract:
  With the growing interest in the use of internet of things (IoT),
machine-to-machine (M2M) communications have become an important networking
paradigm. In this paper, with recent advances in wireless network
virtualization (WNV), we propose a novel framework for M2M communications in
vehicular ad-hoc networks (VANETs) with WNV. In the proposed framework,
according to different applications and quality of service (QoS) requirements
of vehicles, a hypervisor enables the virtualization of the physical vehicular
network, which is abstracted and sliced into multiple virtual networks.
Moreover, the process of resource blocks (RBs) selection and random access in
each virtual vehicular network is formulated as a partially observable Markov
decision process (POMDP), which can achieve the maximum reward about
transmission capacity. The optimal policy for RBs selection is derived by
virtue of a dynamic programming approach. Extensive simulation results with
different system parameters are presented to show the performance improvement
of the proposed scheme.


title:
Polyatomic gases with dynamic pressure: Maximum entropy principle and
  shock structure

abstract:
  This paper is concerned with the analysis of polyatomic gases within the
framework of kinetic theory. Internal degrees of freedom are modeled using a
single continuous variable corresponding to the molecular internal energy.
Non-equilibrium velocity distribution function, compatible with macroscopic
field variables, is constructed using the maximum entropy principle. A proper
collision cross section is constructed which obeys the micro-reversibility
requirement. The source term and entropy production rate are determined in the
form which generalizes the results obtained within the framework of extended
thermodynamics. They can be adapted to appropriate physical situations due to
the presence of parameters. They are also compared with the results obtained
using BGK approximation. For the proposed model the shock structure problem is
thoroughly analyzed.


title:
A molecular dynamics approach to dissipative relativistic hydrodynamics:
  propagation of fluctuations

abstract:
  Relativistic generalization of hydrodynamic theory has attracted much
attention from a theoretical point of view. However, it has many important
practical applications in high energy as well as astrophysical contexts.
Despite various attempts to formulate relativistic hydrodynamics, no definitive
consensus has been achieved. In this work, we propose to test the predictions
of four types of \emph{first-order} hydrodynamic theories for non-perfect
fluids in the light of numerically exact molecular dynamics simulations of a
fully relativistic particle system in the low density regime. In this regard,
we study the propagation of density, velocity and heat fluctuations in a wide
range of temperatures using extensive simulations and compare them to the
corresponding analytic expressions we obtain for each of the proposed theories.
As expected in the low temperature classical regime all theories give the same
results consistent with the numerics. In the high temperature extremely
relativistic regime, not all considered theories are distinguishable from one
another. However, in the intermediate regime, a meaningful distinction exists
in the predictions of various theories considered here. We find that the
predictions of the recent formulation due to Tsumura-Kunihiro-Ohnishi are more
consistent with our numerical results than the traditional theories due to
Meixner, modified Eckart and modified Marle-Stewart.


title:
Bed load proppant transport during slickwater hydraulic fracturing:
  insights from comparisons between published laboratory data and correlations
  for sediment and pipeline slurry transport

abstract:
  Bed load transport is the movement of particles along the top of a bed
through rolling, saltation, and suspension created by turbulent lift above the
bed surface. In recent years, there has been a resurgence of interest in the
idea that bed load transport is significant for proppant transport during
hydraulic fracturing. However, scaling arguments suggest that bed load
transport is only dominant in the laboratory and is negligible at the field
scale. I review laboratory experiments that have been used to develop concepts
of bed load transport in hydraulic fracturing. I also review the scaling
arguments and laboratory results that have been used to argue that viscous
drag, not bed load transport, is dominant at the field scale. I compare
literature correlations for fluvial sediment transport and for pipeline slurry
transport with published laboratory data on proppant transport in slot flow.
The comparisons indicate that fluvial transport correlations are suitable for
predicting the rate of sediment erosion due to flow of proppant-free fluid over
a bed. The pipeline slurry correlations are suitable for predicting the ability
of proppant that is already in suspension to flow in bed transport without
settling, but only if the aspect ratio of the flowing region in the slot is
close to unity. This can occur at the laboratory scale, but not in the field.
The comparison indicates that at low rates of proppant flow, the equilibrium
bed height in a laboratory proppant transport experiment can be predicted from
pipeline slurry correlations. However, as the volumetric flow rate and the
aspect ratio of the flowing region in the slot increase, the applicability of
the pipeline slurry correlations breaks down. Laboratory experiments using
higher volumetric flow rate indicate that bed load transport rates are too low
to be significant at the field scale, even if the flow velocity is very high.


title: Leveraging Video Descriptions to Learn Video Question Answering

abstract:
  We propose a scalable approach to learn video-based question answering (QA):
answer a "free-form natural language question" about a video content. Our
approach automatically harvests a large number of videos and descriptions
freely available online. Then, a large number of candidate QA pairs are
automatically generated from descriptions rather than manually annotated. Next,
we use these candidate QA pairs to train a number of video-based QA methods
extended fromMN (Sukhbaatar et al. 2015), VQA (Antol et al. 2015), SA (Yao et
al. 2015), SS (Venugopalan et al. 2015). In order to handle non-perfect
candidate QA pairs, we propose a self-paced learning procedure to iteratively
identify them and mitigate their effects in training. Finally, we evaluate
performance on manually generated video-based QA pairs. The results show that
our self-paced learning procedure is effective, and the extended SS model
outperforms various baselines.


title: Timestamps for Partial Replication

abstract:
  Maintaining causal consistency in distributed shared memory systems using
vector timestamps has received a lot of attention from both theoretical and
practical prospective. However, most of the previous literature focuses on full
replication where each data is stored in all replicas, which may not be
scalable due to the increasing amount of data. In this report, we investigate
how to achieve causal consistency in partial replicated systems, where each
replica may store different set of data. We propose an algorithm that tracks
causal dependencies via vector timestamp in client-server model for partial
replication. The cost of our algorithm in terms of timestamps size varies as a
function of the manner in which the replicas share data, and the set of
replicas accessed by each client. We also establish a connection between our
algorithm with the previous work on full replication.


title: Sparsey: Event Recognition via Deep Hierarchical Spare Distributed Codes

abstract:
  Visual cortex's hierarchical, multi-level organization is captured in many
biologically inspired computational vision models, the general idea being that
progressively larger scale, more complex spatiotemporal features are
represented in progressively higher areas. However, most earlier models use
localist representations (codes) in each representational field, which we
equate with the cortical macrocolumn (mac), at each level. In localism, each
represented feature/event (item) is coded by a single unit. Our model, Sparsey,
is also hierarchical but crucially, uses sparse distributed coding (SDC) in
every mac in all levels. In SDC, each represented item is coded by a small
subset of the mac's units. SDCs of different items can overlap and the size of
overlap between items can represent their similarity. The difference between
localism and SDC is crucial because SDC allows the two essential operations of
associative memory, storing a new item and retrieving the best-matching stored
item, to be done in fixed time for the life of the model. Since the model's
core algorithm, which does both storage and retrieval (inference), makes a
single pass over all macs on each time step, the overall model's
storage/retrieval operation is also fixed-time, a criterion we consider
essential for scalability to huge datasets. A 2010 paper described a
nonhierarchical version of this model in the context of purely spatial pattern
processing. Here, we elaborate a fully hierarchical model (arbitrary numbers of
levels and macs per level), describing novel model principles like progressive
critical periods, dynamic modulation of principal cells' activation functions
based on a mac-level familiarity measure, representation of multiple
simultaneously active hypotheses, a novel method of time warp invariant
recognition, and we report results showing learning/recognition of
spatiotemporal patterns.


title:
Probing Dy3+ magnetic moments in multiferroic perovskite DyMnO3 by
  optical spectroscopy

abstract:
  We present a detailed temperature-dependent spectroscopic study of DyMnO3
single crystals with distorted perovskite structure. Energies of 36
crystal-field levels of Dy3+ in paramagnetic DyMnO3 were determined. The Dy3+
ground Kramers doublet does not split at T_N^Mn = 39 K and splits below Tlock =
18 K. The splitting grows fast at temperatures near T_N^Dy = 6.5 K and reaches
{\Delta}0 = 11 cm-1 at 4 K. Using the experimental temperature dependence
{\Delta}0(T), we calculate the dysprosium magnetic moment mDy(T) and the
dysprosium contribution into specific heat and magnetic susceptibility.
Analysing all the experimental data, we conclude that the Dy-Mn interaction is
of the Dzyaloshinskii-Moriya type.


title:
Transverse Momentum Distribution in Heavy Ion Collision using q-Weibull
  Formalism

abstract:
  We have implemented the Tsallis q-statistics in the Weibull model of particle
production known as the q-Weibull distribution to describe the
transverse-momentum (pT ) distribution of the charged hadrons at mid-rapidity
measured at RHIC and LHC energies. The model describes the data remarkably well
for the entire pT range measured in nucleus-nucleus and nucleon-nucleon
collisions. The proposed distribution is based on the non-extensive Tsallis
q-statistics which replaces the usual thermal equilibrium assumption of
hydrodynamical models. The parameters of the distribution can be related to the
various aspects of complex dynamics associated with such collision process.


title: Mixed Data and Classification of Transit Stops

abstract:
  An analysis of the characteristics and behavior of individual bus stops can
reveal clusters of similar stops, which can be of use in making routing and
scheduling decisions, as well as determining what facilities to provide at each
stop. This paper provides an exploratory analysis, including several possible
clustering results, of a dataset provided by the Regional Transit Service of
Rochester, NY. The dataset describes ridership on public buses, recording the
time, location, and number of entering and exiting passengers each time a bus
stops. A description of the overall behavior of bus ridership is followed by a
stop-level analysis. We compare multiple measures of stop similarity, based on
location, route information, and ridership volume over time.


title: Big Bounce Genesis and Possible Experimental Tests -- A Brief Review

abstract:
  We review the recent status of big bounce genesis as a new possibility of
using dark matter particle's mass and interaction cross section to test the
existence of a bounce universe at the early stage of evolution in our currently
observed universe. To study the dark matter production and evolution inside the
bounce universe, called big bounce genesis for short, we propose a model
independent approach. We shall present the motivation for proposing big bounce
as well the model independent predictions which can be tested by dark matter
direct searches. A positive finding shall have profound impact on our
understanding of the early universe physics.


title: Models of dielectric relaxation based on completely monotone functions

abstract:
  The relaxation properties of dielectric materials are described, in the
frequency domain, according to one of the several models proposed over the
years: Kohlrausch-Williams-Watts, Cole-Cole, Cole-Davidson, Havriliak-Negami
(with its modified version) and Excess wing model are among the most famous.
Their description in the time domain involves some mathematical functions whose
knowledge is of fundamental importance for a full understanding of the models.
In this work, we survey the main dielectric models and we illustrate the
corresponding time-domain functions. In particular, we stress the attention on
the completely monotone character of the relaxation and response functions. We
also provide a characterization of the models in terms of differential
operators of fractional order.

categories: math-ph cond-mat.mtrl-sci cond-mat.soft math.CV math.MP


title:
Aspects of the physical principles of the proton therapy with inclusion
  of nuclear interactions

abstract:
  The radiotherapy of malignant diseases has reached much progress during the
past decade. Thus, intensity modulated radiation therapy (IMRT) and VMAT
(Rapidarc) now belong to the standard modalities of tumor treatment with high
energy radiation in clinical practice. In recent time, the particle therapy
(protons and partially with heavy carbon ions) has reached an important
completion of these modalities with regard to some suitable applications. In
spite of this enrichment essential features need further research activities
and publications in this field: Nuclear reactions and the role of the released
neutrons, electron capture of positively charged nuclei at lower projectile
energies (e.g. in the environment of the Bragg peak and at the distal end of
the particle track), correct dose delivery in scanning methods by accounting
for the influence of the lateral scatter of beam-lets. Deconvolution methods
can help to overcome these problems, which already occur in radiotherapy of
very small photon beams [1 - 8].


title:
Mean-field models for non-Markovian epidemics on networks: from
  edge-based compartmental to pairwise models

abstract:
  This paper presents a novel extension of the edge-based compartmental model
for epidemics with arbitrary distributions of transmission and recovery times.
Using the message passing approach we also derive a new pairwise-like model for
epidemics with Markovian transmission and an arbitrary recovery period. The new
pairwise-like model allows one to formally prove that the message passing and
edge-based compartmental models are equivalent in the case of Markovian
transmission and arbitrary recovery processes. The edge-based and message
passing models are conjectured to also be equivalent for arbitrary transmission
processes; we show the first step of a full proof of this. The new
pairwise-like model encompasses many existing well-known models that can be
obtained by appropriate reductions. It is also amenable to a relatively
straightforward numerical implementation. We test the theoretical results by
comparing the numerical solutions of the various pairwise-like models to
results based on explicit stochastic network simulations.


title: Modified planar functions and their components

abstract:
  Zhou 2013 introduced modified planar functions to describe $(2^n,2^n,2^n,1)$
relative difference sets $R$ as a graph of a function on the finite field
$\F_{2^n}$, and pointed out that projections of $R$ are difference sets that
can be described by negabent or bent$_4$ functions, which are Boolean functions
given in multivariate form. Objective of this paper is to contribute to the
understanding of these component functions of modified planar functions. We
first completely describe a multivariate version of modified planar functions
in terms of their bent$_4$ components. In the second part we characterize the
component functions of (univariate) modified planar functions in terms of
appropriate generalizations of the Walsh-Hadamard transform, with respect to
which they have a flat spectrum. We hereby obtain a description of modified
planar functions by their components which is similar to that of the classical
planar functions in odd characteristic as a vectorial bent function.


title: The complete $1/N$ expansion of a SYK--like tensor model

abstract:
  A SYK--like model close to the colored tensor models has recently been
proposed \cite{Witten:2016iux}. Building on results obtained in tensor models
\cite{GurSch}, we discuss the complete $1/N$ expansion of the model. We detail
the two and four point functions at leading order. The leading order two point
function is a sum over melonic graphs, and the leading order relevant four
point functions are sums over dressed ladder diagrams. We then show that any
order in the $1/N$ series of the two point function can be written solely in
term of the leading order two and four point functions. The full $1/N$
expansion of arbitrary correlations can be obtained by similar methods.


title: 1.5 billion words Arabic Corpus

abstract:
  This study is an attempt to build a contemporary linguistic corpus for Arabic
language. The corpus produced, is a text corpus includes more than five million
newspaper articles. It contains over a billion and a half words in total, out
of which, there is about three million unique words. The data were collected
from newspaper articles in ten major news sources from eight Arabic countries,
over a period of fourteen years. The corpus was encoded with two types of
encoding, namely: UTF-8, and Windows CP-1256. Also it was marked with two
mark-up languages, namely: SGML, and XML.


title: Fair Public Decision Making

abstract:
  We generalize the classic problem of fairly allocating indivisible goods to
the problem of \emph{fair public decision making}, in which a decision must be
made on several social issues simultaneously, and, unlike the classic setting,
a decision can provide positive utility to multiple players. We extend the
popular fairness notion of proportionality (which is not guaranteeable) to our
more general setting, and introduce three novel relaxations ---
\emph{proportionality up to one issue, round robin share, and pessimistic
proportional share} --- that are also interesting in the classic goods
allocation setting. We show that the Maximum Nash Welfare solution, which is
known to satisfy appealing fairness properties in the classic setting,
satisfies or approximates all three relaxations in our framework. We also
provide polynomial time algorithms and hardness results for finding allocations
satisfying these axioms, with or without insisting on Pareto optimality.


title: Entropic Causal Inference

abstract:
  We consider the problem of identifying the causal direction between two
discrete random variables using observational data. Unlike previous work, we
keep the most general functional model but make an assumption on the unobserved
exogenous variable: Inspired by Occam's razor, we assume that the exogenous
variable is simple in the true causal direction. We quantify simplicity using
R\'enyi entropy. Our main result is that, under natural assumptions, if the
exogenous variable has low $H_0$ entropy (cardinality) in the true direction,
it must have high $H_0$ entropy in the wrong direction. We establish several
algorithmic hardness results about estimating the minimum entropy exogenous
variable. We show that the problem of finding the exogenous variable with
minimum entropy is equivalent to the problem of finding minimum joint entropy
given $n$ marginal distributions, also known as minimum entropy coupling
problem. We propose an efficient greedy algorithm for the minimum entropy
coupling problem, that for $n=2$ provably finds a local optimum. This gives a
greedy algorithm for finding the exogenous variable with minimum $H_1$ (Shannon
Entropy). Our greedy entropy-based causal inference algorithm has similar
performance to the state of the art additive noise models in real datasets. One
advantage of our approach is that we make no use of the values of random
variables but only their distributions. Our method can therefore be used for
causal inference for both ordinal and also categorical data, unlike additive
noise models.


title: B\"acklund transformations between four Lax-integrable 3D equations

abstract:
  We show that four Lax-integrable 3D differential equations are related via
B\"acklund transformations.


title:
The anatomy of the Orion B Giant Molecular Cloud: A local template for
  studies of nearby galaxies

abstract:
  We aim to develop the Orion B Giant Molecular Cloud (GMC) as a local template
for interpreting extra-galactic molecular line observations. We use the
wide-band receiver at the IRAM-30m to spatially and spectrally resolve the
Orion B GMC. The observations cover almost 1 square degree at 26" resolution
with a bandwidth of 32 GHz from 84 to 116 GHz in only two tunings. Among the
mapped spectral lines are the 12CO, 13CO, C18O, C17O, HCN, HNC, 12CN, CCH,
HCO+, N2H+ (1-0), and 12CS, 32SO, SiO, c-C3H2, CH3OH (2-1) transitions. We
introduce the molecular anatomy of the Orion B GMC, including relations between
line intensities and gas column density or far-UV radiation fields, and
correlations between selected line and line ratios. We also obtain a
dust-traced gas mass that is less than about one third the CO-traced mass,
using the standard Xco conversion factor. The presence of overluminous CO can
be traced back to the dependence of the CO intensity on UV illumination. In
fact, while most lines show some dependence on the UV radiation field, CN and
CCH are the most sensitive. Moreover dense cloud cores are almost exclusively
traced by N2H+. Other traditional high density tracers, such as HCN (1-0), are
also easily detected in extended translucent regions at a typical density of
about 500 H2 cm-3. In general, we find no straightforward relation between line
critical density and the fraction of the line luminosity coming from dense gas
regions. Our initial findings demonstrate that the relations between line
(ratio) intensities and environment in GMCs are more complicated than often
assumed. Sensitivity (i.e., the molecular column density), excitation, and
above all chemistry contribute to the observed line intensity distributions.
They must be considered together when developing the next generation of
extra-galactic molecular line diagnostics of mass, density, temperature and
radiation field.


title: Laser Pulsing in Linear Compton Scattering

abstract:
  Previous work on calculating energy spectra from Compton scattering events
has either neglected considering the pulsed structure of the incident laser
beam, or has calculated these effects in an approximate way subject to
criticism. In this paper, this problem has been reconsidered within a linear
plane wave model for the incident laser beam. By performing the proper Lorentz
transformation of the Klein-Nishina scattering cross section, a spectrum
calculation can be created which allows the electron beam energy spread and
emittance effects on the spectrum to be accurately calculated, essentially by
summing over the emission of each individual electron. Such an approach has the
obvious advantage that it is easily integrated with a particle distribution
generated by particle tracking, allowing precise calculations of spectra for
realistic particle distributions in collision. The method is used to predict
the energy spectrum of radiation passing through an aperture for the proposed
Old Dominion University inverse Compton source. Many of the results allow easy
scaling estimates to be made of the expected spectrum.


title:
Error correction with orbital angular momentum of multiple photons
  propagating in a turbulent atmosphere

abstract:
  Orbital angular momentum of photons is an intriguing system for the storage
and transmission of quantum information, but it is rapidly degraded by
atmospheric turbulence. Understanding the noise processes that affect photons
is essential if we desire to protect them. In this paper we use the
infinitesimal propagation equation of Roux to derive a discrete Lindblad
equation, and numerically study the form of the most relevant Lindblad
operators. We find that the dominant Lindblad operators are those that shift
the angular momentum by one unit. We explore possible schemes to protect
quantum information across multiple photons by concatenating a standard quantum
error-correcting code with an error-detecting code for orbital angular
momentum.


title:
Measurement of the t t-bar production cross section using events in the
  e mu final state in pp collisions at sqrt(s) = 13 TeV

abstract:
  The cross section of top quark-antiquark pair production in proton-proton
collisions at sqrt(s) = 13 TeV is measured by the CMS experiment at the LHC,
using data corresponding to an integrated luminosity of 2.2 inverse femtobarns.
The measurement is performed by analyzing events in which the final state
includes one electron, one muon, and two or more jets, at least one of which is
identified as originating from hadronization of a b quark. The measured cross
section is 815 +/- 9 (stat) +/- 38 (syst) +/- 19 (lumi) pb, in agreement with
the expectation from the standard model.


title: The Kato-Nakayama space as a transcendental root stack

abstract:
  We give a functorial description of the Kato-Nakayama space of a fine
saturated log analytic space that is similar in spirit to the functorial
description of root stacks. As a consequence we get a global description of the
comparison map constructed in arXiv:1511.00037 from the Kato-Nakayama space to
the (topological) infinite root stack.


title:
Thermal boundary resistance from transient nanocalorimetry: a multiscale
  modeling approach

abstract:
  The Thermal Boundary Resistance at the interface between a nanosized Al film
and an Al_{2}O_{3} substrate is investigated at an atomistic level. A room
temperature value of 1.4 m^{2}K/GW is found. The thermal dynamics occurring in
time-resolved thermo-reflectance experiments is then modelled via macro-physics
equations upon insertion of the materials parameters obtained from atomistic
simulations. Electrons and phonons non-equilibrium and spatio-temporal
temperatures inhomo- geneities are found to persist up to the nanosecond time
scale. These results question the validity of the commonly adopted lumped
thermal capacitance model in interpreting transient nanocalorimetry
experiments. The strategy adopted in the literature to extract the Thermal
Boundary Resistance from transient reflectivity traces is revised at the light
of the present findings. The results are of relevance beyond the specific
system, the physical picture being general and readily extendable to other
heterojunctions.


title:
ePSproc: Post-processing suite for ePolyScat electron-molecule
  scattering calculations

abstract:
  ePSproc provides codes for post-processing results from ePolyScat (ePS), a
suite of codes for the calculation of quantum scattering problems, developed
and released by Luchesse \& co-workers (Gianturco et al. 1994)(Natalense and
Lucchese 1999)(R. R. Lucchese and Gianturco 2016). ePS is a powerful
computational engine for solving scattering problems, but its inherent
complexity, combined with additional post-processing requirements, ranging from
simple visualizations to more complex processing involving further calculations
based on ePS outputs, present a significant barrier to use for most
researchers. ePSproc aims to lower this barrier by providing a range of
functions for reading, processing and plotting outputs from ePS. Since ePS
calculations are currently finding multiple applications in AMO physics (see
below), ePSproc is expected to have significant reuse potential in the
community, both as a basic tool-set for researchers beginning to use ePS, and
as a more advanced post-processing suite for those already using ePS. ePSproc
is currently written for Matlab/Octave, and distributed via Github:
https://github.com/phockett/ePSproc.


title:
Saturating The Bekenstein-Hawking Entropy Bound With Initial Data Sets
  For Gravitational Collapse

abstract:
  It is possible to find initial states for gravitational collapse whose
entropy approximately saturates the Bekenstein-Hawking entropy of the final
black hole. The prototypical example of such a state is that envisaged by Zurek
and Thorne, and also by Susskind: for a black hole of mass $\sim M$ , a number
$\sim M^2$ of quanta with energies of order $1/M$ are accreted on a timescale
of order $\sim M^3$, an approximate time-reverse of Hawking evaporation. There
is lore that all initial states which saturate the Bekenstein-Hawking entropy
must involve a formation timescale of this order, $M^3$ , and not the much
shorter dynamical timescale $M$ . Counterexamples to this lore have been found
by Sorkin, Wald and Zhang, and also by Hsu and Reeb, in the form of
semiclassical initial data sets. However the spacetimes that correspond to
these counterexamples possess white holes in the past, as well as black holes
in the future, which casts doubt on their physical relevance. We modify the
counterexamples to eliminate the white holes, yielding formation timescales of
order $M^2$ , and argue that the lore is unfounded.


title: Subderivative-subdifferential duality formula

abstract:
  We provide a formula linking the radial subderivative to other subderivatives
and subdifferentials for arbitrary extended real-valued lower semicontinuous
functions.


title:
Effects of Laser Pulse Heating of Copper Photocathodes on
  High-brightness Electron Beam Production at Blowout Regime

abstract:
  Producing high-brightness and high-charge (>100 pC) electron bunches at
blowout regime requires ultrashort laser pulses with high fluence. The effects
of laser pulse heating of the copper photocathode are analyzed in this paper.
The electron and lattice temperature is calculated using an improved
two-temperature model, and an extended Dowell-Schmerge model is employed to
calculate the thermal emittance and quantum efficiency. A time-dependent growth
of the thermal emittance and the quantum efficiency is observed. For a fixed
amount of charge, the projected thermal emittance increases with decreasing
laser radius, and this effect should be taken into account in laser
optimization at blowout regime. Moreover, laser damage threshold fluence is
simulated, showing that the maximum local fluence should be less than 40
mJ/cm^2 to prevent damage to the cathode.


title: Anyons in Geometric Models of Matter

abstract:
  We show that the "geometric models of matter" approach proposed by the first
author can be used to construct models of anyon quasiparticles with fractional
quantum numbers, using 4-dimensional edge-cone orbifold geometries with
orbifold singularities along embedded 2-dimensional surfaces. The anyon states
arise through the braid representation of surface braids wrapped around the
orbifold singularities, coming from multisections of the orbifold normal bundle
of the embedded surface. We show that the resulting braid representations can
give rise to a universal quantum computer.


title: A near-unity efficiency source of entangled guided waves

abstract:
  Surface phonon polaritons are hybrid modes of photons and optical phonons
that can propagate on the surface of a polar dielectric. In this work, we show
that the precise combination of confinement and bandwidth offered by surface
phonon polaritons allows for the ability to create highly efficient sources of
entangled light in the IR/THz. Specifically, phonon polaritons can cause
emitters to preferentially decay by the emission of pairs of surface phonon
polaritons, instead of the previously dominant single-photon emission. We show
that such two-photon emission processes can occur on nanosecond time-scales and
can be nearly two orders of magnitude faster than competing single-photon
transitions, as opposed to being as much as eight to ten orders of magnitude
slower in free space. Our results suggest a fundamentally new design strategy
for quantum light sources in the IR/THz: ones that prefer to emit a relatively
broad spectrum of entangled photons, potentially allowing for new sources of
both single and multiple photons.


title: Prognostics of Surgical Site Infections using Dynamic Health Data

abstract:
  Surgical Site Infection (SSI) is a national priority in healthcare research.
Much research attention has been attracted to develop better SSI risk
prediction models. However, most of the existing SSI risk prediction models are
built on static risk factors such as comorbidities and operative factors. In
this paper, we investigate the use of the dynamic wound data for SSI risk
prediction. There have been emerging mobile health (mHealth) tools that can
closely monitor the patients and generate continuous measurements of many
wound-related variables and other evolving clinical variables. Since existing
prediction models of SSI have quite limited capacity to utilize the evolving
clinical data, we develop the corresponding solution to equip these mHealth
tools with decision-making capabilities for SSI prediction with a seamless
assembly of several machine learning models to tackle the analytic challenges
arising from the spatial-temporal data. The basic idea is to exploit the
low-rank property of the spatial-temporal data via the bilinear formulation,
and further enhance it with automatic missing data imputation by the matrix
completion technique. We derive efficient optimization algorithms to implement
these models and demonstrate the superior performances of our new predictive
model on a real-world dataset of SSI, compared to a range of state-of-the-art
methods.


title:
Space-time Galerkin POD with application in optimal control of
  semi-linear parabolic partial differential equations

abstract:
  In the context of Galerkin discretizations of a partial differential equation
(PDE), the modes of the classical method of Proper Orthogonal Decomposition
(POD) can be interpreted as the ansatz and trial functions of a low-dimensional
Galerkin scheme. If one also considers a Galerkin method for the time
integration, one can similarly define a POD reduction of the temporal
component. This has been described earlier but not expanded upon -- probably
because the reduced time discretization globalizes time which is
computationally inefficient. However, in finite-time optimal control systems,
time \textit{is} a global variable and there is no disadvantage from using a
POD reduced Galerkin scheme in time. In this paper, we provide a newly
developed generalized theory for space-time Galerkin POD, prove its optimality
in the relevant function spaces, show its application for the optimal control
of nonlinear PDEs, and, by means of a numerical example with Burgers' equation,
discuss the competitiveness by comparing to standard approaches.


title:
GANS for Sequences of Discrete Elements with the Gumbel-softmax
  Distribution

abstract:
  Generative Adversarial Networks (GAN) have limitations when the goal is to
generate sequences of discrete elements. The reason for this is that samples
from a distribution on discrete objects such as the multinomial are not
differentiable with respect to the distribution parameters. This problem can be
avoided by using the Gumbel-softmax distribution, which is a continuous
approximation to a multinomial distribution parameterized in terms of the
softmax function. In this work, we evaluate the performance of GANs based on
recurrent neural networks with Gumbel-softmax output distributions in the task
of generating sequences of discrete elements.


title: Semi-automatic Simultaneous Interpreting Quality Evaluation

abstract:
  Increasing interpreting needs a more objective and automatic measurement. We
hold a basic idea that 'translating means translating meaning' in that we can
assessment interpretation quality by comparing the meaning of the interpreting
output with the source input. That is, a translation unit of a 'chunk' named
Frame which comes from frame semantics and its components named Frame Elements
(FEs) which comes from Frame Net are proposed to explore their matching rate
between target and source texts. A case study in this paper verifies the
usability of semi-automatic graded semantic-scoring measurement for human
simultaneous interpreting and shows how to use frame and FE matches to score.
Experiments results show that the semantic-scoring metrics have a significantly
correlation coefficient with human judgment.


title:
The Structure of the Test Function for Phenomenological Modelling of
  Eclipsing Binaries

abstract:
  The dependence of the test function on the phenomenological parameters used
in the "NAV" ("New Algol Variable") algorithm (Andronov, 2012Ap.....55..536A)
is studied. Due to a presence of local minima, the method of minimization
contains two steps: the "brute force" minimization at a grid in the 4D
parameter space, and further iterations using the differential corrections.
This method represents an effective approximation of the light curve using the
special pattern (shape) separately for the primary and secondary minima. The
application of the method to concrete stars is briefly reviewed.


title: Pseudo-time regularization for PDE with solution-dependent diffusion

abstract:
  This work unifies pseudo-time and inexact regularization techniques for
nonmonotone classes of partial differential equations, into a regularized
pseudo-time framework. Convergence of the residual at the predicted rate is
investigated through the idea of controlling the linearization error, and
regularization parameters are defined following this analysis, then assembled
in an adaptive algorithm. The main innovations of this paper include the
introduction of a Picard-like regularization term scaled by its cancellation
effect on the linearization error to stabilize the Newton-like iteration; an
updated analysis of the regularization parameters in terms of minimizing an
appropriate quantity; and, strategies to accelerate the algorithm into the
asymptotic regime. Numerical experiments demonstrate the method on an
anisotropic diffusion problem where the Jacobian is not continuously
differentiable, and a model problem with steep gradients and a thin diffusion
layer.


title:
A Calculus for Conformal Hypersurfaces and new higher Willmore energy
  functionals

abstract:
  The invariant theory for conformal hypersurfaces is studied by treating these
as the conformal infinity of a conformally compact manifold: For a given
conformal hypersurface embedding, a distinguished ambient metric is found
(within its conformal class) by solving a singular version of the Yamabe
problem. Using existence results for asymptotic solutions to this problem, we
develop the details of how to proliferate conformal hypersurface invariants. In
addition we show how to compute the the solution's asymptotics. We also develop
a calculus of conformal hypersurface invariant differential operators and in
particular, describe how to compute extrinsically coupled analogues of
conformal Laplacian powers. Our methods also enable the study of integrated
conformal hypersurface invariants and their functional variations. As a main
application we develop new higher dimensional analogues of the Willmore energy
for embedded surfaces. This complements recent progress on the existence and
construction of such functionals.


title: Scalar curvature and singular metrics

abstract:
  Let $M^n$, $n\ge3$, be a compact differentiable manifold with nonpositive
Yamabe invariant $\sigma(M)$. Suppose $g_0$ is a continuous metric with $V(M,
g_0)=1$, smooth outside a compact set $\Sigma$, and is in $W^{1,p}_{loc}$ for
some $p>n$. Suppose the scalar curvature of $g_0$ is at least $\sigma(M)$
outside $\Sigma$. We prove that $g_0$ is Einstein outside $\Sigma$ if the
codimension of $\Sigma$ is at least $2$. If in addition, $g_0$ is Lipschitz
then $g_0$ is smooth and Einstein after a change the smooth structure. If
$\Sigma$ is a compact embedded hypersurface, and $g_0$ is smooth up to $\Sigma$
from two sides of $\Sigma$, and if the difference of the mean curvatures along
$\Sigma$ at two sides of $\Sigma$ has a fixed appropriate sign. Then $g_0$ is
also Einstein outside $\Sigma$. For manifolds with dimension between $3$ and
$7$ without spin assumption, we obtain a positive mass theorem on an
asymptotically flat manifold for metrics with a compact singular set of
codimension at least $2$.


title: Lipschitz structure and minimal metrics on topological groups

abstract:
  We discuss the problem of deciding when a metrisable topological group $G$
has a canonically defined local Lipschitz geometry. This naturally leads to the
concept of minimal metrics on $G$, that we characterise intrinsically in terms
of a linear growth condition on powers of group elements.
  Combining this with work on the large scale geometry of topological groups,
we also identify the class of metrisable groups admitting a canonical global
Lipschitz geometry.
  In turn, minimal metrics connect with Hilbert's fifth problem for completely
metrisable groups and we show, assuming that the set of squares is sufficiently
rich, that every element of some identity neighbourhood belongs to a
$1$-parameter subgroup.


title: Out-of-Time-Order Correlation in Marginal Many-Body Localized Systems

abstract:
  We show that the out-of-time-order correlation (OTOC) $ \langle W(t)^\dagger
V(0)^\dagger W(t)V(0)\rangle$ in many-body localized (MBL) and marginal MBL
systems can be efficiently calculated by the spectrum bifurcation
renormalization group (SBRG). We find that in marginal MBL systems, the
scrambling time $t_\text{scr}$ follows a stretched exponential scaling with the
distance $d_{WV}$ between the operators $W$ and $V$:
$t_\text{scr}\sim\exp(\sqrt{d_{WV}/l_0})$, which demonstrates Sinai diffusion
of quantum information and the enhanced scrambling by the quantum criticality
in non-chaotic systems.


title: Not Only Horses Wear Blinkers: The Missing Perspectives in IS Research

abstract:
  When we devise a method to address a particular research question, we think
about many things, including the unit of study. But do we think about the
perspective from which we observe whatever it is that's within our field of
view? In the majority of mainstream IS research, one perspective dominates.
Organisations use IS and IT as a means of intervening into a context. And the
behaviour of the phenomena is mostly observed from the viewpoint of those
organisations. Is that viewpoint the only legitimate one for IS research to
adopt? Even if it is, are the clients' interests best served by IS research
that adopts that perspective alone? This paper identifies alternative
perspectives. It draws attention to negative consequences of wearing blinkers
to restrict our field of view, and to opportunities we can grasp by taking off
the blinkers. It proposes that these alternatives need to be defined as being
within the IS discipline rather than outside it.


title: Bihomogeneous symmetric functions

abstract:
  We consider two natural gradings on the space of symmetric functions: by
degree and by length. We introduce a differential operator $T$ that leaves the
components of this double grading invariant and exhibit a basis of
bihomogeneous symmetric functions in which this operator is triangular. This
allows us to compute the eigenvalues of $T$, which turn out to be non-negative
integers.


title: Contact activity and dynamics of the online elite

abstract:
  Humans interact through numerous channels to build and maintain social
connections: they meet face-to-face, initiate phone calls or send text
messages, and interact via social media. Although it is known that the network
of physical contacts, for example, is distinct from the network arising from
communication events via phone calls and instant messages, the extent to which
these networks differ is not clear. In fact, the network structure of these
channels shows large structural variations. Each network of interactions,
however, contains both central and peripheral individuals: central members are
characterized by higher connectivity and can reach a high fraction of the
network within a low number of connections, contrary to the nodes on the
periphery. Here we show that the various channels account for diverse
relationships between pairs of individuals and the corresponding interaction
patterns across channels differ to an extent that hinders the simple reduction
of social ties to a single layer. Furthemore, the origin and purpose of each
network also determine the role of their respective central members: highly
connected individuals in the person-to-person networks interact with their
environment in a regular manner, while members central in the social
communication networks display irregular behavior with respect to their
physical contacts and are more active through rare, social events. These
results suggest that due to the inherently different functions of communication
channels, each one favors different social behaviors and different strategies
for interacting with the environment. Our findings can facilitate the
understanding of the varying roles and impact individuals have on the
population, which can further shed light on the prediction and prevention of
epidemic outbreaks, or information propagation.


title: Symbolic Iterative Solution of Volterra Integral Equations

abstract:
  In this work we show how auxiliary variables can be used to give an efficient
method involving symbolic manipulation and Picard iteration for approximating
solutions of certain Volterra integral equations.


title: Transverse oscillations in a coronal loop triggered by a jet

abstract:
  We detect and analyse transverse oscillations in a coronal loop, lying at the
south east limb of the Sun as seen from the \textit{{Atmospheric Imaging
Assembly}} (AIA) onboard \textit{{Solar Dynamics Observatory}} (SDO). The jet
is believed to trigger transverse oscillations in the coronal loop. The jet
originates from a region close to the coronal loop on 19$^{\rm th}$ September
2014 at 02:01:35 UT. The length of the loop is estimated to be between
377-539~Mm. Only one complete oscillation is detected with an average period of
about $32\pm5$~min. Using MHD seismologic inversion techniques, we estimate the
magnetic field inside the coronal loop to be between $2.68 -4.5$~G. The
velocity of the hot and cool components of the jet is estimated to be
168~km~s$^{-1}$ and 43~km~s$^{-1}$, respectively. The energy density of the jet
is found to be greater than the energy density of the oscillating coronal loop.
Therefore, we conclude that the jet {triggered} transverse oscillations in the
coronal loop. To our knowledge, this is the first coronal loop seismology study
using the properties of a jet propagation {to trigger} oscillations.


title: Planet signatures in the chemical composition of Sun-like stars

abstract:
  There are two possible mechanisms to imprint planet signatures in the
chemical composition of Sun-like stars: i) dust condensation at the early
stages of planet formation, causing a depletion of refractory elements in the
gas accreted by the star in the late stages of its formation; ii) planet
engulfment, enriching the host star in lithium and refractory elements. We
discuss both planet signatures, the influence of galactic chemical evolution,
and the importance of binaries composed of stellar twins as laboratories to
verify abundance anomalies imprinted by planets.


title: Skein relations for tangle Floer homology

abstract:
  In a previous paper, V\'ertesi and the first author used grid-like Heegaard
diagrams to define tangle Floer homology, which associates to a tangle $T$ a
differential graded bimodule $\widetilde{\mathrm{CT}} (T)$. If $L$ is obtained
by gluing together $T_1, \dotsc, T_m$, then the knot Floer homology
$\hat{\mathrm{HFK}}(L)$ of $L$ can be recovered from $\widetilde{\mathrm{CT}}
(T_1), \dotsc, \widetilde{\mathrm{CT}} (T_m)$. In the present paper, we prove
combinatorially that tangle Floer homology satisfies unoriented and oriented
skein relations, generalizing the skein exact triangles for knot Floer
homology.


title:
Nonlinear Dirac equation solitary waves under a spinor force with
  different components

abstract:
  We consider the nonlinear Dirac (NLD) equation in 1+1 dimension with
scalar-scalar self-interaction in the presence of external forces as well as
damping of the form $\gamma^0 f(x,t) - i \mu \gamma^0 \Psi$, where both $f,
\{f_j = r_i e^{i K_j x} \}$ and $\Psi$ are two-component spinors. We develop an
approximate variational approach using collective coordinates (CC) for studying
the time dependent response of the solitary waves to these external forces. In
our previous paper we assumed $K_j=K, ~ j=1,2$ which allowed a transformation
to a simplifying coordinate system, and we also assumed the "small" component
of the external force was zero. Here we include the effects of the small
component and also the case $K_1 \neq K_2$ which dramatically modifies the
behavior of the solitary wave in the presence of these external forces.


title: Error Metrics for Learning Reliable Manifolds from Streaming Data

abstract:
  Spectral dimensionality reduction is frequently used to identify
low-dimensional structure in high-dimensional data. However, learning
manifolds, especially from the streaming data, is computationally and memory
expensive. In this paper, we argue that a stable manifold can be learned using
only a fraction of the stream, and the remaining stream can be mapped to the
manifold in a significantly less costly manner. Identifying the transition
point at which the manifold is stable is the key step. We present error metrics
that allow us to identify the transition point for a given stream by
quantitatively assessing the quality of a manifold learned using Isomap. We
further propose an efficient mapping algorithm, called S-Isomap, that can be
used to map new samples onto the stable manifold. We describe experiments on a
variety of data sets that show that the proposed approach is computationally
efficient without sacrificing accuracy.


title: Mathematical modeling of hysteresis loops in ferroelectric materials

abstract:
  In published papers, the Gibbs free energy of ferroelectric materials has
usually been quantified by the retention of 6th or 8th order polarization
terms. In this paper, a newly analytical model of Gibbs free energy, thereout,
a new model of polarization-electric field hysteresis loops in ferroelectric
materials has been derived mathematically. As a model validation, four patterns
of polarization-electric field hysteresis loops of ferroelectric materials have
been depicted by using the model. The calculated results indicated that the
self-similar model can characterize the various patterns of hysteresis loops in
ferroelectric materials through adjusting the external excitation or the
synthetically parameter (e.g., electric, temperature, and stress, etc.)
employed in the model.


title:
Low-rank and Adaptive Sparse Signal (LASSI) Models for Highly
  Accelerated Dynamic Imaging

abstract:
  Sparsity-based approaches have been popular in many applications in image
processing and imaging. Compressed sensing exploits the sparsity of images in a
transform domain or dictionary to improve image recovery from undersampled
measurements. In the context of inverse problems in dynamic imaging, recent
research has demonstrated the promise of sparsity and low-rank techniques. For
example, the patches of the underlying data are modeled as sparse in an
adaptive dictionary domain, and the resulting image and dictionary estimation
from undersampled measurements is called dictionary-blind compressed sensing,
or the dynamic image sequence is modeled as a sum of low-rank and sparse (in
some transform domain) components (L+S model) that are estimated from limited
measurements. In this work, we investigate a data-adaptive extension of the L+S
model, dubbed LASSI, where the temporal image sequence is decomposed into a
low-rank component and a component whose spatiotemporal (3D) patches are sparse
in some adaptive dictionary domain. We investigate various formulations and
efficient methods for jointly estimating the underlying dynamic signal
components and the spatiotemporal dictionary from limited measurements. We also
obtain efficient sparsity penalized dictionary-blind compressed sensing methods
as special cases of our LASSI approaches. Our numerical experiments demonstrate
the promising performance of LASSI schemes for dynamic magnetic resonance image
reconstruction from limited k-t space data compared to recent methods such as
k-t SLR and L+S, and compared to the proposed dictionary-blind compressed
sensing method.


title: The subalgebras of G2

abstract:
  We classify subalgebras of the complex simple Lie algebra of type G2 up to
conjugacy (by an inner automorphism).


title: On classification of extremal non-holomorphic conformal field theories

abstract:
  Rational chiral conformal field theories are organized according to their
genus, which consists of a modular tensor category $\mathcal{C}$ and a central
charge $c$. A long-term goal is to classify unitary rational conformal field
theories based on a classification of unitary modular tensor categories. We
conjecture that for any unitary modular tensor category $\mathcal{C}$, there
exists a unitary chiral conformal field theory $V$ so that its modular tensor
category $\mathcal{C}_V$ is $\mathcal{C}$. In this paper, we initiate a
mathematical program in and around this conjecture. We define a class of
extremal vertex operator algebras with minimal conformal dimensions as large as
possible for their central charge, and non-trivial representation theory. We
show that there are finitely many different characters of extremal vertex
operator algebras V possessing at most three different irreducible modules.
Moreover, we list all of the possible characters for such vertex operator
algebras with $c$ at most 48.


title:
Singular Hyperbolicity and sectional Lyapunov exponents of various
  orders

abstract:
  It is given notions of singular hyperbolicity and sectional Lyapunov
exponents of orders beyond the classical ones, namely, other dimensions besides
the dimension 2 and the full dimension of the central subbundle of the singular
hyperbolic set. It is obtained a characterization of dominated splittings,
partial and singular hyperbolicity in this broad sense, by using Lyapunov
exponents and the notion of infinitesimal Lyapunov functions. Furthermore, it
is given alternative requirements to obtain singular hyperbolicity. As an
application we obtain some results related to singular hyperbolic sets for
flows.


title:
An alternative formulation for exact scaling relations in hydrodynamic
  and magnetohydrodynamic turbulence

abstract:
  We propose an alternative formulation for the exact relations in
three-dimensional homogeneous turbulence using two-point statistics. Our
finding is illustrated with incompressible hydrodynamic, standard and Hall
magnetohydrodynamic turbulence. In this formulation, the cascade rate of an
inviscid invariant of turbulence can be expressed simply in terms of mixed
second-order structure functions. Besides the usual variables like the velocity
${\bf u}$, vorticity $\omega$, magnetic field ${\bf b}$ and the current ${\bf
j}$, the vectors ${\bf u } \times {\boldsymbol \omega}$, ${\bf u} \times {\bf
b}$ and ${\bf j} \times {\bf b}$ are also found to play a key role in the
turbulent cascades. The current methodology offers a simple algebraic form
which is specially interesting to study anisotropic space plasmas like the
solar wind, with in principle a faster statistical convergence than the
classical laws written in terms of third-order correlators.


title: Accelerated Stochastic ADMM with Variance Reduction

abstract:
  Alternating Direction Method of Multipliers (ADMM) is a popular method in
solving Machine Learning problems. Stochastic ADMM was firstly proposed in
order to reduce the per iteration computational complexity, which is more
suitable for big data problems. Recently, variance reduction techniques have
been integrated with stochastic ADMM in order to get a fast convergence rate,
such as SAG-ADMM and SVRG-ADMM,but the convergence is still suboptimal w.r.t
the smoothness constant. In this paper, we propose a new accelerated stochastic
ADMM algorithm with variance reduction, which enjoys a faster convergence than
all the other stochastic ADMM algorithms. We theoretically analyze its
convergence rate and show its dependence on the smoothness constant is optimal.
We also empirically validate its effectiveness and show its priority over other
stochastic ADMM algorithms.


title:
Resolving the Geometry of the Innermost Relativistic Jets in Active
  Galactic Nuclei

abstract:
  In the current paradigm, it is believed that the compact VLBI radio core of
radio-loud AGNs represents the innermost upstream regions of relativistic
outflows. These regions of AGN jets have generally been modeled by a conical
outflow with roughly constant opening angle and flow speed. Nonetheless, some
works suggest that a parabolic geometry would be more appropriate to fit the
high energy spectral energy distribution properties and it has been recently
found that, at least in some nearby radio-galaxies, the geometry of the
innermost regions of the jet is parabolic. We compile here multi-frequency core
sizes of archival data to investigate the typically unresolved upstream regions
of the jet geometry of a sample of 56 radio-loud AGNs. Data combined from the
sources considered here is not consistent with the classic picture of a conical
jet starting in the vicinity of the super-massive black hole (SMBH), and may
exclude a pure parabolic outflow solution, but rather suggest an intermediate
solution with quasi-parabolic streams, which are frequently seen in numerical
simulations. Inspection of the large opening angles near the SMBH and the range
of the Lorentz factors derived from our results support our analyses. Our
result suggests that the conical jet paradigm in AGNs needs to be re-examined
by mm/sub-mm VLBI observations.


abstract:
  Unsupervised learning with generative adversarial networks (GANs) has proven
hugely successful. Regular GANs hypothesize the discriminator as a classifier
with the sigmoid cross entropy loss function. However, we found that this loss
function may lead to the vanishing gradients problem during the learning
process. To overcome such a problem, we propose in this paper the Least Squares
Generative Adversarial Networks (LSGANs) which adopt the least squares loss
function for the discriminator. We show that minimizing the objective function
of LSGAN yields minimizing the Pearson $\chi^2$ divergence. There are two
benefits of LSGANs over regular GANs. First, LSGANs are able to generate higher
quality images than regular GANs. Second, LSGANs perform more stable during the
learning process. We evaluate LSGANs on five scene datasets and the
experimental results show that the images generated by LSGANs are of better
quality than the ones generated by regular GANs. We also conduct two comparison
experiments between LSGANs and regular GANs to illustrate the stability of
LSGANs.


title:
The Reasonable Effectiveness of Agent-Based Simulations in Evolutionary
  Game Theory

abstract:
  This is a Reply to comments published in Physics of Life Reviews, on our
article "Evolutionary game theory using agent-based methods" (Physics of Life
Reviews, 2016, arXiv:1404.0994).


title: Spectral action in Betti Geometric Langlands

abstract:
  Let $X$ be a smooth projective curve, $G$ a reductive group, and $Bun_G(X)$
the moduli of $G$-bundles on $X$. For each point of $X$, the Satake category
acts by Hecke modifications on sheaves on $Bun_G(X)$. We show that, for sheaves
with nilpotent singular support, the action is locally constant with respect to
the point of $X$. This equips sheaves with nilpotent singular support with a
module structure over perfect complexes on the Betti moduli $Loc_{G^\vee}(X)$
of dual group local systems. In particular, we establish the "automorphic to
Galois" direction in the Betti Geometric Langlands correspondence -- to each
indecomposable automorphic sheaf, we attach a dual group local system -- and
define the Betti version of V. Lafforgue's excursion operators.


title: Coloring Complexes and Combinatorial Hopf Monoids

abstract:
  We generalize the notion of coloring complex of a graph to linearized
combinatorial Hopf monoids. These are a generalization of the notion of
coloring complex of a graph. We determine when a combinatorial Hopf monoid has
such a construction, and discover some inequalities that are satisfied by the
quasisymmetric function invariants associated to the combinatorial Hopf monoid.
We show that the collection of all such coloring complexes forms a
combinatorial Hopf monoid, which is the terminal object in the category of
combinatorial Hopf monoids with convex characters. We also study several
examples of combinatorial Hopf monoids.


title:
Electrostatic Forces Mediate Fast Association of Calmodulin and the
  Intrinsically Disordered Regulatory Domain of Calcineurin

abstract:
  Intrinsically disordered proteins (IDPs) and proteins with intrinsically
disordered regions (IDRs) govern a daunting number of physiological processes.
For such proteins, molecular mechanisms governing their interactions with
proteins involved in signal transduction pathways remain unclear. Using the
folded, calcium-loaded calmodulin (CaM) interaction with the calcineurin
regulatory IDP as a prototype for IDP-mediated signal transduction events, we
uncover the interplay of IDP structure and electrostatic interactions in
determining the kinetics of protein-protein association. Using an array of
biophysical approaches including stopped-flow and computational simulation, we
quantify the relative contributions of electrostatic interactions and
conformational ensemble characteristics in determining association kinetics of
calmodulin (CaM) and the calcineurin regulatory domain (CaN RD). Our chief
findings are that CaM/CN RD association rates are strongly dependent on ionic
strength and that observed rates are largely determined by the
electrostatically-driven interaction strength between CaM and the narrow CaN RD
calmodulin recognition domain. These studies highlight a molecular mechanism of
controlling signal transduction kinetics that may be utilized in wide-ranging
signaling cascades that involve IDPs.


title:
Geometry and Dynamics of Gaussian Wave Packets and their Wigner
  Transforms

abstract:
  We find a relationship between the dynamics of the Gaussian wave packet and
the dynamics of the corresponding Gaussian Wigner function from the
Hamiltonian/symplectic point of view. The main result states that the momentum
map corresponding to the natural action of the symplectic group on the Siegel
upper half space yields the covariance matrix of the corresponding Gaussian
Wigner function. This fact, combined with Kostant's coadjoint orbit covering
theorem, establishes a symplectic/Poisson-geometric connection between the two
dynamics. The Hamiltonian formulation naturally gives rise to corrections to
the potential terms in the dynamics of both the wave packet and the Wigner
function, thereby resulting in slightly different sets of equations from the
conventional classical ones. We numerically investigate the effect of the
correction term and demonstrate that it improves the accuracy of the dynamics
as an approximation to the dynamics of expectation values of observables.


title:
Biderivations and commutative post-Lie algebra structure on the
  Schr\"odinger-Virasoro Lie algebra

abstract:
  In this paper, we characterize the biderivations of Schr\"odinger-Virasoro
Lie algebra. We get a classes of non-inner and non-skewsymmetric biderivations.
As application, we characterize the commutative post-Lie algebra structures on
Schr\"odinger-Virasoro Lie algebra.


title:
SuperCDMS SNOLAB Low-Mass Detectors: Ultra-Sensitive Phonon Calorimeters
  for a Sub-GeV Dark Matter Search

abstract:
  We present the technical design for the SuperCDMS high-voltage, low-mass dark
matter detectors, designed to be sensitive to dark matter down to 300 MeV/$c^2$
in mass and resolve individual electron-hole pairs from low-energy scattering
events in high-purity Ge and Si crystals. In this paper we discuss some of the
studies and technological improvements which have allowed us to design such a
sensitive detector, including advances in phonon sensor design and detector
simulation. With this design we expect to achieve better than 10 eV (5 eV)
phonon energy resolution in our Ge (Si) detectors, and recoil energy resolution
below 1eV by exploiting Luke-Neganov phonon generation of charges accelerated
in high fields.


title:
Cosmological model from the holographic equipartition law with a
  modified R\'{e}nyi entropy

abstract:
  Cosmological equations were recently derived by Padmanabhan from the
expansion of cosmic space due to the difference between the degrees of freedom
on the surface and in the bulk in a region of space. In this study, a modified
R\'{e}nyi entropy is applied to Padmanabhan's `holographic equipartition law',
by regarding the Bekenstein--Hawking entropy as a nonextensive Tsallis entropy
and using a logarithmic formula of the original R\'{e}nyi entropy.
Consequently, the acceleration equation including an extra driving term (such
as a time-varying cosmological term) can be derived in a homogeneous,
isotropic, and spatially flat universe. When a specific condition is
mathematically satisfied, the extra driving term is found to be constant-like
as if it is a cosmological constant. Interestingly, the order of the
constant-like term is naturally consistent with the order of the cosmological
constant measured by observations, because the specific condition constrains
the value of the constant-like term.


title: Charmed-Bottom Mesons from Lattice QCD

abstract:
  We present ground state spectra of mesons containing a charm and a bottom
quark. For the charm quark we use overlap valence quarks while a
non-relativistic formulation is utilized for the bottom quark on a background
of 2+1+1 flavors HISQ gauge configurations generated by the MILC collaboration.
The hyperfine splitting between $1S$ states of $B_c$ mesons is found to be
$56^{+4}_{-3}$ MeV. We also study the baryons containing only charm and bottom
quarks and predict their ground state masses. Results are obtained at three
lattice spacings.


title:
Universal scaling of the electronic and the elastic energies of small
  polarons revealed by high-throughput first-principles calculations

abstract:
  Formation of self-trapped holes (STH) in a comprehensive list of scintillator
materials, including halides and chalcogenides, are studied using an accurate
and computationally efficient first-principles method, the polaron
self-interaction correction (pSIC). The key characteristics of small hole
polarons, including their geometries, energies and degree of localization, are
found vastly different from halides to oxides to systems with open-shell
cations. Nevertheless, we find a universal linear relation between the energy
gap separating the bound hole level from the valence band maximum and the
elastic energy associated with the lattice displacement field that accompanies
the polaron.


title:
Fixed points of left reversible semigroup of isometry mappings in Banach
  spaces

abstract:
  In this paper, we prove the existence of a common fixed point in $C(K)$, the
Chebyshev center of K, for a left reversible semigroup of isometry mappings.
This existence result improves the results obtained by Lim et al. and Brodskii
and Milman.


title:
Batched Gaussian Process Bandit Optimization via Determinantal Point
  Processes

abstract:
  Gaussian Process bandit optimization has emerged as a powerful tool for
optimizing noisy black box functions. One example in machine learning is
hyper-parameter optimization where each evaluation of the target function
requires training a model which may involve days or even weeks of computation.
Most methods for this so-called "Bayesian optimization" only allow sequential
exploration of the parameter space. However, it is often desirable to propose
batches or sets of parameter values to explore simultaneously, especially when
there are large parallel processing facilities at our disposal. Batch methods
require modeling the interaction between the different evaluations in the
batch, which can be expensive in complex scenarios. In this paper, we propose a
new approach for parallelizing Bayesian optimization by modeling the diversity
of a batch via Determinantal point processes (DPPs) whose kernels are learned
automatically. This allows us to generalize a previous result as well as prove
better regret bounds based on DPP sampling. Our experiments on a variety of
synthetic and real-world robotics and hyper-parameter optimization tasks
indicate that our DPP-based methods, especially those based on DPP sampling,
outperform state-of-the-art methods.


title:
Extracting energy from non-equilibrium fluctuations without using
  information

abstract:
  Extracting energy from fluctuations has been an everlasting endeavor. An
important strategy is to use information-based operation, which allows energy
extraction even from thermal fluctuations. However, it remains unclear whether
a blind external operation, ignorant of such fluctuations, will also work.
Assuming such a small operation, we find that energy extraction requires a
negative response spectrum in a certain frequency region, which inevitably
requires an internal power source to maintain. Energy is then extracted by
operating the system at these frequencies. Negative response is intrinsic to
any system that adapts to a slow external operation, which could be realized
through integral feedback control. These are demonstrated through a solvable
model.


title: Time-varying return predictability in the Chinese stock market

abstract:
  China's stock market is the largest emerging market all over the world. It is
widely accepted that the Chinese stock market is far from efficiency and it
possesses possible linear and nonlinear dependence. We study the predictability
of returns in the Chinese stock market by employing the wild bootstrap
automatic variance ratio test and the generalized spectral test. We find that
the return predictability vary over time and significant return predictability
is observed around market turmoils. Our findings are consistent with the
Adaptive Markets Hypothesis and have practical implications for market
participants.


title:
Immediate price impact of a stock and its warrant: Power-law or
  logarithmic model?

abstract:
  Based on the order flow data of a stock and its warrant, the immediate price
impacts of market orders are estimated by two competitive models, the power-law
model (PL model) and the logarithmic model (LG model). We find that the PL
model is overwhelmingly superior to the LG model, regarding the robustness of
the estimated parameters and the accuracy of out-of-sample forecasting. We also
find that the price impacts of ask and bid orders are consistent with each
other for filled trades, since significant positive correlations are observed
between the model parameters of both types of orders. Our findings may provide
valuable insights for optimal trade execution.


title: Indication of Collective Flow and Transparency in p-p Collisions at LHC

abstract:
  The mid-rapidity transverse momentum spectra of hadrons and the available
rapidity distributions of the strange hadrons produced in p-p collisions at LHC
energy root(snn) = 0.9 TeV and root(snn)= 7.0 TeV have been studied using a
unified statistical thermal freeze-out model. The calculated results are found
to be in good agreement with the experimental data. The theoretical fits of the
transverse momentum spectra using the model calculations provide the thermal
freeze-out conditions in terms of the temperature and collective flow
parameters for different hadronic species. The study reveal the presence of
significant collective flow and a well defined temperature in the system thus
indicating the formation of a thermally equilibrated hydrodynamic system in p-p
collisions at LHC. Moreover, the fits to the available experimental rapidity
distributions data of strange hadrons show the effect of almost complete
transparency in p-p collisions at LHC. The transverse momentum distributions of
protons and Kaons produced in p-p collisions at root(snn) = 200 GeV and
root(snn)= 2.76 TeV have also been reproduced successfully. The model
incorporates longitudinal as well as a transverse hydrodynamic flow. The
contributions from heavier decay resonances have also been taken into account.
We have also imposed the criteria of exact strangeness conservation in the
system.


title:
A novel variable-separation method based on sparse representation for
  stochastic partial differential equations

abstract:
  In this paper, we propose a novel variable-separation (NVS) method for
generic multivariate functions. The idea of NVS is extended to to obtain the
solution in tensor product structure for stochastic partial differential
equations (SPDEs).
  Compared with many widely used variation-separation methods, NVS shares their
merits but has less computation complexity and better efficiency.
  NVS can be used to get the separated representation of the solution for SPDE
in a systematic enrichment manner.
  No iteration is performed at each enrichment step. This is a significant
improvement compared with proper generalized decomposition. Because the
stochastic functions of the separated representations obtained by NVS depend on
the previous terms, this impacts on the computation efficiency and brings great
challenge for numerical simulation for the problems in high stochastic
dimensional spaces.
  In order to overcome the difficulty, we propose an improved least angle
regression algorithm (ILARS) and a hierarchical sparse low rank tensor
approximation (HSLRTA) method based on sparse regularization. For ILARS, we
explicitly give the selection of the optimal regularization parameters at each
step based on least angle regression algorithm (LARS) for lasso problems such
that ILARS is much more efficient.
  HSLRTA hierarchically decomposes a high dimensional problem into some low
dimensional problems and brings an accurate approximation for the solution to
SPDEs in high dimensional stochastic spaces using limited computer resource.
  A few numerical examples are presented to illustrate the efficacy of the
proposed methods.


title: Infrared Radiation from Rough Surface

abstract:
  We consider generation of diffusive radiation by a charged particle passing
through a random stack of plates in the infrared region. Diffusive radiation
originates due to multiple scattering of pseudophotons on the plates. To
enhance the radiation intensity one needs to make the scattering more
effective. For this goal we suggest to use materials with negative dielectric
constant .


title: Unions of random walk and percolation on infinite graphs

abstract:
  We consider a random object that is associated with both random walks and
random media, specifically, the superposition of a configuration of subcritical
Bernoulli percolation on an infinite connected graph and the trace of the
simple random walk on the same graph. We investigate asymptotics for the number
of vertices of the enlargement of the trace of the walk until a fixed time,
when the time tends to infinity. This process is more highly self-interacting
than the range of random walk, which yields difficulties. We show a law of
large numbers on vertex-transitive transient graphs. We compare the process on
a vertex-transitive graph with the process on a finitely modified graph of the
original vertex-transitive graph and show their behaviors are similar. We show
that the process fluctuates almost surely on a certain non-vertex-transitive
graph. On the two-dimensional integer lattice, by investigating the size of the
boundary of the trace, we give an estimate for variances of the process
implying a law of large numbers. We give an example of a graph with unbounded
degrees on which the process behaves in a singular manner. As by-products, some
results for the range and the boundary, which will be of independent interest,
are obtained.


title: Finite quasi-quantum groups of diagonal type

abstract:
  The goal of the present paper is to classify an interesting class of
elementary quasi-Hopf algebras, or equivalently, finite-dimensional pointed
Majid algebras. By a Tannaka-Krein type duality, this determines a big class of
pointed finite tensor categories. Based on some interesting observations of
normalized 3-cocycles on finite abelian groups, we elucidate an explicit
connection between our objective pointed Majid algebras and finite-dimensional
pointed Hopf algebras over finite abelian groups. With a help of this
connection and the successful theory of diagonal Nichols algebras over abelian
groups, we provide a conceptual classification of finite-dimensional graded
pointed Majid algebras of diagonal type. Some efficient methods of construction
are also given.


title: Descent of Flatness and the Direct Summand Conjecture

abstract:
  In the central theorem of this article we prove the following: if $R$ is a
complete regular local ring and $B$ is the integral closure of $R$ in the
algebraic closure of the fraction field of $R$, then $\Hom_R(B, R) \neq 0$. Our
proof of this theorem does not involve almost mathematics and it works for all
characteristics. As consequences we derive the validity of a) descent of
flatness for integral extensions of Noetherian rings and b) direct summand
conjecture due to M. Hochster.


title: The weak Bruhat order for random walks on Coxeter groups

abstract:
  We show that for the simple random walk on a Coxeter group generated by the
Coxeter generators and identity, the likelihoods of being at any pair of states
respect the weak Bruhat order. That is, after any number of steps, the most
likely element is the identity, probabilities decrease along any geodesic from
the identity, and the least likely element is the longest element, if the group
is finite. The result remains true when different generators have different
probabilities, so long as the identity is at least as likely as any other.