title:
Achieving Selective Damage Interrogation and Sub-Wavelength Resolution
  in Thin Plates with Embedded Metamaterial Acoustic Lenses

abstract:
  In this study, we present an approach to ultrasonic beamforming and high
resolution identification of acoustic sources having critical implications for
structural health monitoring technology. The proposed concept is based on the
design of dynamically tailored structural elements via embedded acoustic
metamaterial lenses. This approach provides a completely new alternative to
conventional phased-array technology enabling the formation of steerable and
collimated (or focused) ultrasonic beams by exploiting a single transducer. The
ultrasonic beams can be steered by simply tuning the frequency of the
excitation. Also, the embedded lens can be designed to achieve sub-wavelength
resolution to incipient clustered damage.


title: Impact of local integrals of motion to metastable non-equilibrium states

abstract:
  We analyse the stationary behaviour of correlations in a strongly correlated
Bose gas out of equilibrium. The dynamics are triggered by a quench of the
interaction starting from the strongly interacting limit where the system is in
a perfect Mott state. Despite the complete integrability of our theoretical
description, we find seemingly thermal behaviour for the experimentally
measurable correlations at large interactions. Quite opposed, away from the
strongly interacting regime these correlation functions show highly non-thermal
stationary values. This behaviour is explained by overlaps of the integrals of
motion with the observable and the initial state in an effective thermal
ensemble. These results suggest that non-equilibrium Mazur equalities are an
efficient way to calculate short range correlations for arbitrary integrable
models.


title:
A Distributive Lattice Connected with Arithmetic Progressions of Length
  Three

abstract:
  Let $\mathcal{T}$ be a collection of 3-element subsets $S$ of $\{1,
\ldots,n\}$ with the property that if $i<j<k$ and $a<b<c$ are two 3-element
subsets in $S$, then there exists an integer sequence $x_1 < x_2 < \cdots <
x_n$ such that $x_i, x_j, x_k$ and $x_a, x_b, x_c$ are arithmetic progressions.
We determine the number of such collections $\mathcal{T}$ and the number of
them of maximum size. These results confirm two conjectures of Noam Elkies.


title:
Thin Sequences and Their Role in $H^p$ Theory, Model Spaces, and Uniform
  Algebras

abstract:
  In this paper we revisit some facts about thin interpolating sequences in the
unit disc from three perspectives: uniform algebras, model spaces, and $H^p$
spaces. We extend the notion of asymptotic interpolation to $H^p$ spaces, for
$1 \leq p \leq \infty$, providing several new ways to think about these
sequences.


title:
Formation and collimation of relativistic MHD jets - simulations and
  radio maps

abstract:
  We present results of magnetohydrodynamic (MHD) simulations of jet formation
and propagation, discussing a variety of astrophysical setups. In the first
approach we consider simulations of relativistic MHD jet formation, considering
jets launched from the surface of a Keplerian disk, demonstrating numerically -
for the first time - the self-collimating ability of relativistic MHD jets. We
obtain Lorentz factors up to about 10 while acquiring a high degree of
collimation of about 1 degree. We then present synchrotron maps calculated from
the intrinsic jet structure derived from the MHD jet formation simulation. We
finally present (non-relativistic) MHD simulations of jet lauching, treating
the transition between accretion and ejection. These setups include a physical
magnetic diffusivity which is essential for loading the accretion material onto
the outflow. We find relatively high mass fluxes in the outflow, of the order
of 20-40 % of the accretion rate.


title: Radio frequency spectroscopy of the attractive Hubbard model in a trap

abstract:
  Attractive interaction between fermions can lead to pairing and superfluidity
in an optical lattice. In contrast to the `continuum', on a lattice the trap
induced density variation can generate a non monotonic profile of the pairing
amplitude, and completely modify the spectral signatures of any possible
pseudogap phase. Using a tool that fully captures the inhomogeneity and strong
thermal fluctuations, we demonstrate how the crucial radio frequency signatures
of pairing are `inverted' in a trapped attractive fermion lattice compared to
the traditional continuum case. These features would be central in interpreting
any spectroscopic hint of fermion pairing and superfluidity.


title:
Transverse steady bifurcation of viscous shock solutions of a
  hyperbolic-parabolic model in a strip

abstract:
  In this article we derive rigorously a nonlinear, steady, bifurcation through
spectral bifurcation (i.e., eigenvalues of the linearized equation crossing the
imaginary axis) for a class of hyperbolic-parabolic model in a strip. This is
related to "cellular instabilities" occuring in detonation and MHD. Our results
extend to multiple dimensions the results of Franz Achleitner and Peter
Szmolyan (Saddle-node bifurcation of viscous profiles) on 1D steady bifurcation
of viscous shock profiles; en passant, changing to an appropriate moving
coordinate frame, we recover and somewhat sharpen results of Benjamin Texier
and Kevin Zumbrun (Galloping instability of viscous shock waves) on transverse
Hopf bifurcation, showing that the bifurcating time-periodic solution is in
fact a spatially periodic traveling wave. Our technique consists of a
Lyapunov-Schmidt type of reduction, which prepares the equations for the
application of other bifurcation techniques. For the reduction in transverse
modes, a general Fredholm Alternative-type result is derived, allowing us to
overcome the unboundedness of the domain and the lack of compact embeddings;
this result apply to general closed operators.


title: Identification of Employees Using RFID in IE-NTUA

abstract:
  During the last decade with the rapid increase in indoor wireless
communications, location-aware services have received a great deal of attention
for commercial, public-safety, and a military application, the greatest
challenge associated with indoor positioning methods is moving object data and
identification. Mobility tracking and localization are multifaceted problems,
which have been studied for a long time in different contexts. Many potential
applications in the domain of WSNs require such capabilities. The mobility
tracking needs inherent in many surveillance, security and logistic
applications. This paper presents the identification of employees in National
Technical University in Athens (IE-NTUA), when the employees access to a
certain area of the building (enters and leaves to/from the college), Radio
Frequency Identification (RFID) applied for identification by offering special
badges containing RFID-tags.


title:
Heuristics for Routing and Spiral Run-time Task Mapping in NoC-based
  Heterogeneous MPSOCs

abstract:
  This paper describes a new Spiral Dynamic Task Mapping heuristic for mapping
applications onto NoC-based Heterogeneous MPSoC. The heuristic proposed in this
paper attempts to map the tasks of an applications that are most related to
each other in spiral manner and to find the best possible path load that
minimizes the communication overhead. In this context, we have realized a
simulation environment for experimental evaluations to map applications with
varying number of tasks onto an 8x8 NoC-based Heterogeneous MPSoCs platform, we
demonstrate that the new mapping heuristics with the new modified dijkstra
routing algorithm proposed are capable of reducing the total execution time and
energy consumption of applications when compared to state-of the-art run-time
mapping heuristics reported in the literature.


title: Multi-Branch Matching Pursuit with applications to MIMO radar

abstract:
  We present an algorithm, dubbed Multi-Branch Matching Pursuit (MBMP), to
solve the sparse recovery problem over redundant dictionaries. MBMP combines
three different paradigms: being a greedy method, it performs iterative signal
support estimation; as a rank-aware method, it is able to exploit signal
subspace information when multiple snapshots are available; and, as its name
foretells, it leverages a multi-branch (i.e., tree-search) strategy that allows
us to trade-off hardware complexity (e.g. measurements) for computational
complexity. We derive a sufficient condition under which MBMP can recover a
sparse signal from noiseless measurements. This condition, named MB-coherence,
is met when the dictionary is sufficiently incoherent. It incorporates the
number of branches of MBMP and it requires fewer measurements than other
conditions (e.g. the Neuman ERC or the cumulative coherence). As such,
successful recovery with MBMP is guaranteed for dictionaries that do not
satisfy previously known conditions.


title: Structure-Aware Dynamic Scheduler for Parallel Machine Learning

abstract:
  Training large machine learning (ML) models with many variables or parameters
can take a long time if one employs sequential procedures even with stochastic
updates. A natural solution is to turn to distributed computing on a cluster;
however, naive, unstructured parallelization of ML algorithms does not usually
lead to a proportional speedup and can even result in divergence, because
dependencies between model elements can attenuate the computational gains from
parallelization and compromise correctness of inference. Recent efforts toward
this issue have benefited from exploiting the static, a priori block structures
residing in ML algorithms. In this paper, we take this path further by
exploring the dynamic block structures and workloads therein present during ML
program execution, which offers new opportunities for improving convergence,
correctness, and load balancing in distributed ML. We propose and showcase a
general-purpose scheduler, STRADS, for coordinating distributed updates in ML
algorithms, which harnesses the aforementioned opportunities in a systematic
way. We provide theoretical guarantees for our scheduler, and demonstrate its
efficacy versus static block structures on Lasso and Matrix Factorization.


title:
Electrostatic plasma instabilities driven by neutral gas flows in the
  solar chromosphere

abstract:
  We investigate electrostatic plasma instabilities of Farley-Buneman (FB) type
driven by quasi-stationary neutral gas flows in the solar chromosphere. The
role of these instabilities in the chromosphere is clarified. We find that the
destabilizing ion thermal effect is highly reduced by the Coulomb collisions
and can be ignored for the chromospheric FB-type instabilities. On the
contrary, the destabilizing electron thermal effect is important and causes a
significant reduction of the neutral drag velocity triggering the instability.
The resulting threshold velocity is found as function of chromospheric height.
Our results indicate that the FB type instabilities are still less efficient in
the global chromospheric heating than the Joule dissipation of the currents
driving these instabilities. This conclusion does not exclude the possibility
that the FB type instabilities develop in the places where the cross-field
currents overcome the threshold value and contribute to the heating locally.
Typical length-scales of plasma density fluctuations produced by these
instabilities are determined by the wavelengths of unstable modes, which are in
the range $10-10^2$ cm in the lower chromosphere, and $10^2-10^3$ cm in the
upper chromosphere. These results suggest that the decimetric radio waves
undergoing scattering (scintillations) by these plasma irregularities can serve
as a tool for remote probing of the solar chromosphere at different heights.


title:
On quantitative analysis of interband recombination dynamics: Theory and
  application to bulk ZnO

abstract:
  The issue of the quantitative analysis of time-resolved photoluminescence
experiments is addressed by developing and describing two approaches for
determination of unimolecular lifetime, bimolecular recombination coefficient,
and equilibrium free-carrier concentration, based on a quite general
second-order expression of the electron-hole recombination rate. Application to
the case of band-edge emission of ZnO single crystals is reported, evidencing
the signature of sub-nanosecond second-order recombination dynamics for optical
transitions close to the interband excitation edge. The resulting findings are
in good agreement with the model prediction and further confirm the presence,
formerly evidenced in literature by non-optical methods, of near-surface
conductive layers in ZnO crystals with sheet charge densities of about
3{\div}5*10^13 cm^-2


title:
Modes and Mode Volumes of Leaky Optical Cavities and Plasmonic
  Nanoresonators

abstract:
  Electromagnetic cavity modes in photonic and plasmonic resonators offer rich
and attractive regimes for tailoring the properties of light-matter
interactions. Yet there is a disturbing lack of a precise definition for what
constitutes a cavity mode, and as a result their mathematical properties remain
largely unspecified. The lack of a definition is evidenced in part by the
diverse nomenclature at use - "resonance", "leaky mode", "quasimode", to name
but a few - suggesting that the dissipative nature of cavity modes somehow
makes them different from other modes, but an explicit distinction is rarely
made. This perspective article aims to introduce the reader to some of the
subtleties and working definitions that can be rigorously applied when
describing the modal properties of leaky optical cavities and plasmonic
nanoresonators. We describe some recent development in the field, including
{calculation methods for quasinormal modes of both photonic and plasmonic
resonators and the concept of a generalized effective mode volume, and we}
illustrate the theory with several representative cavity structures from the
fields of photonic crystals and nanoplasmonics.


title: Consistency of Causal Inference under the Additive Noise Model

abstract:
  We analyze a family of methods for statistical causal inference from sample
under the so-called Additive Noise Model. While most work on the subject has
concentrated on establishing the soundness of the Additive Noise Model, the
statistical consistency of the resulting inference methods has received little
attention. We derive general conditions under which the given family of
inference methods consistently infers the causal direction in a nonparametric
setting.


title:
Investigation of the X-ray Emission of the Large Arcade Flare of 2 March
  1993

abstract:
  A large arcade flare of 2 March 1993 has been investigated using X-ray
observations recorded by the {\sl Yohkoh} and GOES satellites and the {\sl
Compton Gamma Ray Observatory}. We analyzed quasi-periodicity of the hard-X-ray
(HXR) pulses in the flare impulsive phase and found close similarity between
the quasi-periodic sequence of the pulses with that observed in another large
arcade flare of 2 November 1991. This similarity helped to explain the strong
HXR pulses which were recorded at the end of the impulsive phase, as due to an
inflow of dense plasma (coming from the chromospheric evaporation) into the
acceleration volume inside the cusp. In HXR images a high flaring loop was seen
with a triangular cusp structure at the top, where the electrons were
efficiently accelerated. The sequence of HXR images allowed us to investigate
complicated changes in the precipitation of the accelerated electrons toward
the flare footpoints. We have shown that all these impulsive-phase observations
can be easily explained in terms of the model of electron acceleration in
oscillating magnetic traps located within the cusp structure. Some soft-X-ray
(SXR) images were available for the late decay phase. They show a long arcade
of SXR loops. Important information about the evolution of the flare during the
slow decay phase is contained in the time variation of the temperature, $T(t)$,
and emission measure, EM$(t)$. This information is the following: i) weak
heating occurs during the slow decay phase and it slowly decreases; ii) the
decrease in the heating determines slow and smooth decrease in EM; iii) the
coupling between the heating and the amount of the hot plasma makes the flare
evolve along a sequence of quasi-steady states during the slow decay phase (QSS
evolution).


title: Quantum gases in optical lattices

abstract:
  The experimental realization of correlated quantum phases with ultracold
gases in optical lattices and their theoretical understanding has witnessed
remarkable progress during the last decade. In this review we introduce basic
concepts and tools to describe the many-body physics of quantum gases in
optical lattices. This includes the derivation of effective lattice
Hamiltonians from first principles and an overview of the emerging quantum
phases. Additionally, state-of-the-art numerical tools to quantitatively treat
bosons or fermions on different lattices are introduced.


title:
First results of the experiment to search for double beta decay of 106Cd
  with 106CdWO4 crystal scintillator in coincidence with four crystals HPGe
  detector

abstract:
  An experiment to search for double beta processes in 106Cd by using cadmium
tungstate crystal scintillator enriched in 106Cd (106CdWO4) in coincidence with
the four crystals HPGe detector GeMulti is in progress at the STELLA facility
of the Gran Sasso underground laboratory of INFN (Italy). The 106CdWO4
scintillator is viewed by a low-background photomultiplier tube through a lead
tungstate crystal light-guide produced from deeply purified archaeological lead
to suppress gamma quanta from the photomultiplier tube. Here we report the
first results of the experiment after 3233 hours of the data taking. A few new
improved limits on double beta processes in 106Cd are obtained, in particular
T1/2(2nuECb+) > 8.4e20 yr at 90% C.L.


title: Vertex-Detector R&D for CLIC

abstract:
  A detector concept based on hybrid planar pixel-detector technology is under
development for the CLIC vertex detector. It comprises fast, low-power and
small-pitch readout ASICs implemented in 65 nm CMOS technology (CLICpix)
coupled to ultra-thin sensors via low-mass interconnects. The power dissipation
of the readout chips is reduced by means of power pulsing, allowing for a
cooling system based on forced gas flow. In this paper the CLIC vertex-detector
requirements are reviewed and the current status of R&D on sensors, readout and
detector integration is presented.


title: Black hole binary remnant mass and spin: A new phenomenological formula

abstract:
  We perform a set of 38 numerical simulations of equal-mass BH binaries in a
configuration where the BH spins in the binary are equal in both magnitude and
direction, to study precession effects. We vary the initial direction of the
total spin S with respect to the orbital angular momentum L, covering the 2
dimensional space of orientation angles with 38 configurations consisting of 36
configurations distributed in the azimuthal angle phi and polar angle theta,
and two configurations on the poles. In all cases, we set the initial
dimensionless BH spins to 0.8. We observe that during the late-inspiral stage,
the total angular momentum of the system J remains within 5 deg of its original
direction, with the largest changes in direction occurring when the spins are
nearly counter-aligned with the orbital angular momentum. We also observe that
the angle between S and L is nearly conserved during the inspiral phase. These
two dynamical properties allow us to propose a new phenomenological formula for
the final mass and spin of merged BHs in terms of the individual masses and
spins of the progenitor binary at far separations. We determine coefficients of
this formula (in the equal-mass limit) using a least-squares fit to the results
of this new set of 38 runs, an additional set of five new configurations with
spins aligned/counteraligned with the orbital angular momentum, and over 100
recent simulations. We find that our formulas reproduce the remnant mass and
spin of these simulations to within a relative error of 2.5%. We discuss the
region of validity of this dynamical picture for precessing unequal-mass
binaries. Finally, we perform a statistical study to see the consequence of
this new formula for distributions of spin-magnitudes and remnant masses with
applications to BH-spin distributions and gravitational radiation in
cosmological scenarios involving several mergers.

categories: gr-qc astro-ph.CO astro-ph.GA astro-ph.HE


title: Making the cut: improved ranking and selection for large-scale inference

abstract:
  Identifying leading measurement units from a large collection is a common
inference task in various domains of large-scale inference. Testing approaches,
which measure evidence against a null hypothesis rather than effect magnitude,
tend to overpopulate lists of leading units with those associated with low
measurement error. By contrast, local maximum likelihood (ML) approaches tend
to favor units with high measurement error. Available Bayesian and empirical
Bayesian approaches rely on specialized loss functions that result in similar
deficiencies. We describe and evaluate a generic empirical Bayesian ranking
procedure that populates the list of top units in a way that maximizes the
expected overlap between the true and reported top lists for all list sizes.
The procedure relates unit-specific posterior upper tail probabilities with
their empirical distribution to yield a ranking variable. It discounts
high-variance units less than popular non-ML methods and thus achieves improved
operating characteristics in the models considered.


title:
HYPERDIRE: HYPERgeometric functions DIfferential REduction: MATHEMATICA
  based packages for differential reduction of generalized hypergeometric
  functions: $F_D$ and $F_S$ Horn-type hypergeometric functions of three
  variables

abstract:
  HYPERDIRE is a project devoted to the creation of a set of Mathematica based
programs for the differential reduction of hypergeometric functions. The
current version includes two parts: the first one, FdFunction, for
manipulations with Appell hypergeometric functions $F_D$ of $r$ variables; and
the second one, FsFunction, for manipulations with Lauricella-Saran
hypergeometric functions $F_S$ of three variables. Both functions are related
with one-loop Feynman diagrams.
  The published version includes also Chapter 5 with two theorems about
structure of coefficients of epsilon-expansion of the Horn-type hypergeometric
functions. As illustration, the first three coefficients of epsilon-expansion
for the Appell hypergeometric function FD of r-variables are explicitly
evaluated.


title: The discriminant power of RNA features for pre-miRNA recognition

abstract:
  Computational discovery of microRNAs (miRNA) is based on pre-determined sets
of features from miRNA precursors (pre-miRNA). These feature sets used by
current tools for pre-miRNA recognition differ in construction and dimension.
Some feature sets are composed of sequence-structure patterns commonly found in
pre-miRNAs, while others are a combination of more sophisticated RNA features.
Current tools achieve similar predictive performance even though the feature
sets used - and their computational cost - differ widely. In this work, we
analyze the discriminant power of seven feature sets, which are used in six
pre-miRNA prediction tools. The analysis is based on the classification
performance achieved with these feature sets for the training algorithms used
in these tools. We also evaluate feature discrimination through the F-score and
feature importance in the induction of random forests. More diverse feature
sets produce classifiers with significantly higher classification performance
compared to feature sets composed only of sequence-structure patterns. However,
small or non-significant differences were found among the estimated
classification performances of classifiers induced using sets with
diversification of features, despite the wide differences in their dimension.
Based on these results, we applied a feature selection method to reduce the
computational cost of computing the feature set, while maintaining discriminant
power. We obtained a lower-dimensional feature set, which achieved a
sensitivity of 90% and a specificity of 95%. Our feature set achieves a
sensitivity and specificity within 0.1% of the maximal values obtained with any
feature set while it is 34x faster to compute. Even compared to another feature
set, which is the computationally least expensive feature set of those from the
literature which perform within 0.1% of the maximal values, it is 34x faster to
compute.


title:
Semi-empirical calculation of quenching factors for scintillators: new
  results

abstract:
  New results of calculation of quenching factors for ions in scintillators in
semi-empirical approach described in [V.I. Tretyak, Astropart. Phys. 33 (2010)
40] are presented. In particular, they give additional arguments in favour of
hypothesis that quenching factors for different particles can be described with
the same Birks factor kB, if all the data were collected in the same conditions
and processed in the same way.


title:
The energy conservation law in hydrodynamics vs the pseudo-law of
  alternative energy. Comment on 'Alternative energy vs pseudoscience' and the
  papers cited and not cited therein

abstract:
  A series of papers in the ISJAEE Journal on 'dam-free hydroelectric power
station' concluded by paper: Zotyev, D. B., Alternative energy vs
pseudo-science, ISJAEE. 2013. 8(130). P.131-136, is reviewed and commented. A
comparison with the generally accepted energy conservation law in hydrodynamics
reveals a disappointingly low scientific level of the reviewed papers (both
pro- and contra- the dam-free concept), not excluding the published
peer-reviewer reports. In the present version we emphasize that the ISJAEE
journal published several papers, which neglect and reject the basic physical
concepts, such as the Bernoulli integral, the energy conservation law in
hydrodynamics, the wave function of photon and some others, with all these
rejected concepts being far beyond the scientific scope of the journal. Some
readers will be more concerned about the energy equation in hydrodynamics, in
its theoretical form or in the Bernoulli integral form as being more
traditional in technical hydromechanics. Some readers will be shocked with the
statement that a photon does not possess the wave function. Overall, in this
way or in that way, all readers will hardly stay unsurprised.


title:
Finite-volume and partial quenching effects in the magnetic
  polarizability of the neutron

abstract:
  There has been much progress in the experimental measurement of the electric
and magnetic polarizabilities of the nucleon. Similarly, lattice QCD
simulations have recently produced dynamical QCD results for the magnetic
polarizability of the neutron approaching the chiral regime. In order to
compare the lattice simulations with experiment, calculation of partial
quenching and finite-volume effects is required prior to an extrapolation in
quark mass to the physical point. These dependencies are described using chiral
effective field theory. Corrections to the partial quenching effects associated
with the sea-quark-loop electric charges are estimated by modelling corrections
to the pion cloud. These are compared to the uncorrected lattice results. In
addition, the behaviour of the finite-volume corrections as a function of pion
mass is explored. Box sizes of approximately 7 fm are required to achieve a
result within 5% of the infinite-volume result at the physical pion mass. A
variety of extrapolations are shown at different box sizes, providing a
benchmark to guide future lattice QCD calculations of the magnetic
polarizabilities. A relatively precise value for the physical magnetic
polarizability of the neutron is presented, beta_n = 1.93(11)stat(8)sys x 10^-4
fm^3, which is in agreement with current experimental results.


title:
Testing the disjunction hypothesis using Voronoi diagrams with
  applications to genetics

abstract:
  Testing of the disjunction hypothesis is appropriate when each gene or
location studied is associated with multiple $p$-values, each of which is of
individual interest. This can occur when more than one aspect of an underlying
process is measured. For example, cancer researchers may hope to detect genes
that are both differentially expressed on a transcriptomic level and show
evidence of copy number aberration. Currently used methods of $p$-value
combination for this setting are overly conservative, resulting in very low
power for detection. In this work, we introduce a method to test the
disjunction hypothesis by using cumulative areas from the Voronoi diagram of
two-dimensional vectors of $p$-values. Our method offers much improved power
over existing methods, even in challenging situations, while maintaining
appropriate error control. We apply the approach to data from two published
studies: the first aims to detect periodic genes of the organism
Schizosaccharomyces pombe, and the second aims to identify genes associated
with prostate cancer.


title: Unsupervised Feature Learning by Deep Sparse Coding

abstract:
  In this paper, we propose a new unsupervised feature learning framework,
namely Deep Sparse Coding (DeepSC), that extends sparse coding to a multi-layer
architecture for visual object recognition tasks. The main innovation of the
framework is that it connects the sparse-encoders from different layers by a
sparse-to-dense module. The sparse-to-dense module is a composition of a local
spatial pooling step and a low-dimensional embedding process, which takes
advantage of the spatial smoothness information in the image. As a result, the
new method is able to learn several levels of sparse representation of the
image which capture features at a variety of abstraction levels and
simultaneously preserve the spatial smoothness between the neighboring image
patches. Combining the feature representations from multiple layers, DeepSC
achieves the state-of-the-art performance on multiple object recognition tasks.


title: Steerable optical tweezers for ultracold atom studies

abstract:
  We report on the implementation of an optical tweezer system for controlled
transport of ultracold atoms along a narrow, static confinement channel. The
tweezer system is based on high-efficiency acousto-optical deflectors and
offers two-dimensional control over beam position. This opens up the
possibility for tracking the transport channel when shuttling atomic clouds
along the guide, forestalling atom spilling. Multiple clouds can be tracked
independently by time-shared tweezer beams addressing individual sites in the
channel. The deflectors are controlled using a multichannel direct digital
synthesizer, which receives instructions on a sub-microsecond time scale from a
field-programmable gate array. Using the tweezer system, we demonstrate
sequential binary splitting of an ultracold $\rm^{87}Rb$ cloud into $2^5$
clouds.


title: EXMOVES: Classifier-based Features for Scalable Action Recognition

abstract:
  This paper introduces EXMOVES, learned exemplar-based features for efficient
recognition of actions in videos. The entries in our descriptor are produced by
evaluating a set of movement classifiers over spatial-temporal volumes of the
input sequence. Each movement classifier is a simple exemplar-SVM trained on
low-level features, i.e., an SVM learned using a single annotated positive
space-time volume and a large number of unannotated videos.
  Our representation offers two main advantages. First, since our mid-level
features are learned from individual video exemplars, they require minimal
amount of supervision. Second, we show that simple linear classification models
trained on our global video descriptor yield action recognition accuracy
approaching the state-of-the-art but at orders of magnitude lower cost, since
at test-time no sliding window is necessary and linear models are efficient to
train and test. This enables scalable action recognition, i.e., efficient
classification of a large number of different actions even in large video
databases. We show the generality of our approach by building our mid-level
descriptors from two different low-level feature representations. The accuracy
and efficiency of the approach are demonstrated on several large-scale action
recognition benchmarks.


title: Energy Transport in Trapped Ion Chains

abstract:
  We experimentally study energy transport in chains of trapped ions. We use a
pulsed excitation scheme to rapidly add energy to the local motional mode of
one of the ions in the chain. Subsequent energy readout allows us to determine
how the excitation has propagated throughout the chain. We observe energy
revivals that persist for many cycles. We study the behavior with an increasing
number of ions of up to 37 in the chain, including a zig-zag configuration. The
experimental results agree well with the theory of normal mode evolution. The
described system provides an experimental toolbox for the study of
thermodynamics of closed systems and energy transport in both classical and
quantum regimes.


title: Compactness Results for Sequences of Approximate Biharmonic Maps

abstract:
  In this article, we prove energy quantization for approximate (intrinsic and
extrinsic) biharmonic maps into spheres where the approximate map is in $L \log
L$. Moreover, we demonstrate that if the $L\log L$ norm of the approximate maps
does not concentrate, the image of the bubbles are connected without necks.


title: Escape from the boundary in Markov population processes

abstract:
  Density dependent Markov population processes in large populations of size
$N$ were shown by Kurtz (1970, 1971) to be well approximated over finite time
intervals by the solution of the differential equations that describe their
average drift, and to exhibit stochastic fluctuations about this deterministic
solution on the scale $\sqrt N$ that can be approximated by a diffusion
process. Here, motivated by an example from evolutionary biology, we are
concerned with describing how such a process leaves an absorbing boundary.
Initially, one or more of the populations is of size much smaller than $N$, and
the length of time taken until all populations have sizes comparable to $N$
then becomes infinite as $N \to \infty$. Under suitable assumptions, we show
that in the early stages of development, up to the time when all populations
have sizes at least $N^{1-\alpha}$, for $1/3 < \alpha < 1$, the process can be
accurately approximated in total variation by a Markov branching process.
Thereafter, the process is well approximated by the deterministic solution
starting from the original initial point, but with a random time delay.
Analogous behaviour is also established for a Markov process approaching an
equilibrium on a boundary, where one or more of the populations become extinct.


title: Yet another application of marginals of multivariate Gibbs distributions

abstract:
  We give yet another example of the usefulness of working with marginals of
multivariate Gibbs distributions (Cerquetti, 2013) in deriving Bayesian
nonparametric estimators under Gibbs priors in species sampling problems. Here
in particular we substantially reduce length and complexity of the proofs in
Bacallado et al. (2013, Th. 1, and Th. 2) for looking backward probabilities
under incomplete information.


title:
Probing nuclear symmetry energy at high densities using pion, kaon, eta
  and photon productions in heavy-ion collisions

abstract:
  The high-density behavior of nuclear symmetry energy is among the most
uncertain properties of dense neutron-rich matter. Its accurate determination
has significant ramifications in understanding not only the reaction dynamics
of heavy-ion reactions especially those induced by radioactive beams but also
many interesting phenomena in astrophysics, such as the explosion mechanism of
supernova and the properties of neutron stars. The heavy-ion physics community
has devoted much effort during the last few years to constrain the high-density
symmetry using various probes. In particular, the pion-/pion+ ratio has been
most extensively studied both theoretically and experimentally. All models have
consistently predicted qualitatively that the pion-/pion+ ratio is a sensitive
probe of the high-density symmetry energy especially with beam energies near
the pion production threshold. However, the predicted values of the pion-/pion+
ratio are still quite model dependent mostly because of the complexity of
modeling pion production and reabsorption dynamics in heavy-ion collisions,
leading to currently still controversial conclusions regarding the high-density
behavior of nuclear symmetry energy from comparing various model calculations
with available experimental data. As more pion-/pion+ data become available and
a deeper understanding about the pion dynamics in heavy-ion reactions is
obtained, more penetrating probes, such as the kaon+/kaon0 ratio, eta meson and
high energy photons are also being investigated or planned at several
facilities. Here, we review some of our recent contributions to the community
effort of constraining the high-density behavior of nuclear symmetry energy in
heavy-ion collisions. In addition, the status of some worldwide experiments for
studying the high-density symmetry energy, including the HIRFL-CSR external
target experiment (CEE) are briefly introduced.


title: Hidden-Strangeness Partners of X(3872)

abstract:
  Decay properties of hidden-strangeness partners of X(3872) are studied in
tetra-quark pictures. As the results, it is seen that their decay properties
are strongly model dependent, and therefore, experimental studies of them will
select a realistic model.


title:
Convergence rate of weak Local Linearization schemes for stochastic
  differential equations with additive noise

abstract:
  There exists a diversity of weak Local Linearization (LL) schemes for the
integration of stochastic differential equations with additive noise, which
differ with respect to the algorithm that is employed in the numerical
implementation of the weak Local Linear discretizations. On the contrary to the
Local Linear discretization, the rate of convergence of the LL schemes has not
been considered up to now. In this work, a general theorem about this issue is
derived and further is applied to a number of specific schemes. As application,
the convergence rate of weak LL schemes for equations with jumps is also
presented.


title: The Bessel Period Functional on SO(5): The Nontempered Case

abstract:
  For automorphic representations in the nontempered cuspidal spectrum of
$\mathrm{SO}_5$, we prove the refined Gan-Gross-Prasad conjecture by
establishing a precise Bessel period formula, in which the square of the global
Bessel period is expressed as an Euler product of regularized local Bessel
period integrals of matrix coefficients.


title: Random Basketball Routing for ZigBee based Sensor Networks

abstract:
  Random basketball routing (BR) \cite {Hwang} is a simple protocol that
integrates MAC and multihop routing in a cross-layer optimized manner. Due to
its lightness and performance, BR would be quite suitable for sensor networks,
where communication nodes are usually simple devices. In this paper, we
describe how we implemented BR in a ZigBee-based (IEEE 802.15.4) sensor
network. In \cite{Hwang}, it is verified that BR takes advantages of dynamic
environments (in particular, node mobility), however, here we focus on how BR
works under static situations. For implementation purposes, we add some
features such as destination RSSI measuring and loop-free procedure, to the
original BR. With implemented testbed, we compare the performance of BR with
that of the simplified AODV with CSMA/CA. The result is that BR has merits in
terms of number of hops to traverse the network. Considering the simple
structure of BR and its possible energy-efficiency, we can conclude that BR can
be a good candidate for sensor networks both under dynamic- and static
environments.


title: Affine Stratification of $\mathcal A_4$

abstract:
  We construct an affine stratification for $\mathcal A_4(\mathbb C)$ of length
6, in the sense of Roth and Vakil, which gives us an upper bound of 6 for the
cohomological dimension of $\mathcal A_4(\mathbb C)$. We conjecture that in
general for arbitrary $g$ the cohomological dimension of $\mathcal A_g$ is
equal to $g(g-1)/2$.


title:
NGC 5824: a luminous outer halo globular cluster with an intrinsic
  abundance spread

abstract:
  We present a detailed study of the strengths of the calcium triplet
absorption lines in the spectra of a large sample of red giant members of the
luminous outer Galactic halo globular cluster NGC 5824. The spectra were
obtained with the FORS2 and GMOS-S multi-object spectrographs at the VLT and
the Gemini-S telescope, respectively. By comparing the line strengths of the
NGC 5824 stars with those for red giants in clusters with well established
abundances, we conclude that there is an intrinsic abundance dispersion in NGC
5824 characterized by an inter-quartile range in [Fe/H] of 0.10 dex and a total
range of ~0.3 dex. As for omega-Cen and M22, the abundance distribution shows a
steep rise on the metal-poor side and a shallower decline on the metal-rich
side. There is also some indication that the distribution is not unimodal with
perhaps 3 distinct abundance groupings present. NGC 5824 has a further unusual
characteristic: the outer surface density profile shows no signs of a tidal
cutoff. Instead the profile has a power-law distribution with cluster stars
detected to a radius exceeding 400 pc. We postulate that NGC 5824 may be the
remnant nuclear star cluster of a now disrupted dwarf galaxy accreted during
the formation of the Galaxy's halo. We further speculate that the presence of
an intrinsic [Fe/H] spread is the characteristic that distinguishes former
nuclear star clusters from other globular clusters.


title: Network Coded Rate Scheduling for Two-way Relay Networks

abstract:
  We investigate a scheduling scheme incorporating network coding and channel
varying information for the two-way relay networks. Our scheduler aims at
minimizing the time span needed to send all the data of each source of the
network. We consider three channel models, time invariant channels, time
varying channels with finite states and time varying Rayleigh fading channels.
We formulate the problem into a manageable optimization problem, and get a
closed form scheduler under time invariant channels and time varying channel
with finite channel states. For Rayleigh fading channels, we focus on the relay
node operation and propose heuristic power allocation algorithm resemblant to
water filling algorithm. By simulations, we find that even if the channel
fluctuates randomly, the average time span is minimized when the relay node
transmits/schedules network coded data as much as possible.


title: The High-z Quasar Hubble Diagram

abstract:
  Two recent discoveries have made it possible for us to begin using high-z
quasars as standard candles to construct a Hubble Diagram (HD) at z > 6. These
are (1) the recognition from reverberation mapping that a relationship exists
between the optical/UV luminosity and the distance of line-emitting gas from
the central ionizing source. Thus, together with a measurement of the velocity
of the line-emitting gas, e.g., via the width of BLR lines, such as Mg II, a
single observation can therefore in principle provide a determination of the
black hole's mass; and (2) the identification of quasar ULAS J1120+0641 at z =
7.085, which has significantly extended the redshift range of these sources,
providing essential leverage when fitting theoretical luminosity distances to
the data. In this paper, we use the observed fluxes and Mg II line-widths of
these sources to show that one may reasonably test the predicted high-z
distance versus redshift relationship, and we assemble a sample of 20 currently
available high-z quasars for this exercise. We find a good match between theory
and observations, suggesting that a more complete, high-quality survey may
indeed eventually produce an HD to complement the highly-detailed study already
underway (e.g., with Type Ia SNe, GRBs, and cosmic chronometers) at lower
redshifts. With the modest sample we have here, we show that the R_h=ct
Universe and LCDM both fit the data quite well, though the smaller number of
free parameters in the former produces a more favorable outcome when we
calculate likelihoods using the Akaike, Kullback, and Bayes Information
Criteria. These three statistical tools result in similar probabilities,
indicating that the R_h=ct Universe is more likely than LCDM to be correct, by
a ratio of about 85% to 15%.


title: Accelerated, Parallel and Proximal Coordinate Descent

abstract:
  We propose a new stochastic coordinate descent method for minimizing the sum
of convex functions each of which depends on a small number of coordinates
only. Our method (APPROX) is simultaneously Accelerated, Parallel and PROXimal;
this is the first time such a method is proposed. In the special case when the
number of processors is equal to the number of coordinates, the method
converges at the rate $2\bar{\omega}\bar{L} R^2/(k+1)^2 $, where $k$ is the
iteration counter, $\bar{\omega}$ is an average degree of separability of the
loss function, $\bar{L}$ is the average of Lipschitz constants associated with
the coordinates and individual functions in the sum, and $R$ is the distance of
the initial point from the minimizer. We show that the method can be
implemented without the need to perform full-dimensional vector operations,
which is the major bottleneck of existing accelerated coordinate descent
methods. The fact that the method depends on the average degree of
separability, and not on the maximum degree of separability, can be attributed
to the use of new safe large stepsizes, leading to improved expected separable
overapproximation (ESO). These are of independent interest and can be utilized
in all existing parallel stochastic coordinate descent algorithms based on the
concept of ESO.


title:
An Iterative Algorithm for Optimal Carrier Sensing Threshold in Random
  CSMA/CA Wireless Networks

abstract:
  We investigate the optimal carrier sensing threshold in random CSMA/CA
networks considering the effect of binary exponential backoff. We propose an
iterative algorithm for optimizing the carrier sensing threshold and hence
maximizing the area spectral efficiency. We verify that simulations are
consistent with our analytical results.


title:
SPLASH: The Southern Parkes Large-Area Survey in Hydroxyl - First
  Science from the Pilot Region

abstract:
  SPLASH (the Southern Parkes Large-Area Survey in Hydroxyl) is a sensitive,
unbiased and fully-sampled survey of the Southern Galactic Plane and Galactic
Centre in all four ground-state transitions of the hydroxyl (OH) radical. The
survey provides a deep census of 1612-, 1665-, 1667- and 1720-MHz OH absorption
and emission from the Galactic ISM, and is also an unbiased search for maser
sources in these transitions. We present here first results from the SPLASH
pilot region, which covers Galactic longitudes 334 to 344 degrees and latitudes
of -2 to +2 degrees. Diffuse OH is widely detected in all four transitions,
with optical depths that are always small (averaged over the Parkes beam), and
with departures from LTE common even in the 1665- and 1667-MHz main lines. To a
3$\sigma$ sensitivity of 30 mK, we find no evidence of OH envelopes extending
beyond the CO-bright regions of molecular cloud complexes, and conclude that
the similarity of the OH excitation temperature and the level of the continuum
background is at least partly responsible for this. We detect masers and maser
candidates in all four transitions, approximately 50 per cent of which are new
detections. This implies that SPLASH will produce a substantial increase in the
known population of ground-state OH masers in the Southern Galactic Plane.


title: Comment on Dark Matter Capture in Neutron Stars with Exotic Phases

abstract:
  In this short paper, we argue the issue on dark matter capture in neutron
stars. After summarizing the whole scenario and the introduction of previous
studies along this line, we propose some potentially important effects due to
the appearance of exotic phases such as neutron superfluidity, meson
condensation and quark superconductivity. Those effects might be sizable and
alter the previous results.


title:
The near threshold $\pi^- p \to \eta n$ reaction in an effective
  Lagrangian approach

abstract:
  The near threshold $\pi^- p \to \eta n$ reaction is studied within an
effective Lagrangian approach and the isobar model. By considering the
contributions from $s$- and $u$-channel nucleon pole and $N^{*}(1535)$
resonance, the total and differential cross sections of the $\pi^- p \to \eta
n$ reaction near threshold are calculated. Our theoretical results can fairly
reproduce the current experimental data. It is also shown that while the
center-of-mass energy lies in the range from the reaction threshold up to
$1.65$ GeV, $s$-channel $N^{*}(1535)$ resonance plays the dominant role. The
effect from nucleon pole is found to be small but the interference terms
between the $N^*(1535)$ resonance and the nucleon pole are significant. The
contributions from $t$-channel processes are negligible in the present
calculation.


title: Polarization Observables for Kaon Photoproduction from Polarized Protons

abstract:
  The search for undiscovered excited states of the nucleon continues to be a
focus of experiments at Jefferson Lab.Recent LQCD calculations have confirmed
long-standing quark-model predictions of many more states than have so far been
identified.A large effort for the N-star program has been launched using the
CLAS detector to provide the database that will allow nearly model-independent
partial wave analyses to be carried out in the search for such states.
Polarization observables play a crucial role in this effort, as they are
essential in disentangling overlapping resonant and non-resonant amplitudes. In
2010, double-polarization data were taken at JLab using circularly polarized
photons incident on a transversely polarized frozen-spin butanol target. Our
current analysis yields preliminary data of the T and F asymmetries for kaon
photoproduction final states, which are compared to predictions of recent
multipole analyses. This work is the first of its kind and will significantly
broaden the world database for these reactions.


title:
Transient first-order interference of two independent thermal light
  beams

abstract:
  By analyzing the first-order interference of two independent thermal light
beams with both classical and quantum theories, we conclude that it is
impossible to observe the transient first-order interference pattern by
superposing two independent thermal light beams even if the degeneracy
parameter of thermal light is much greater than one. The result suggests that
the classical model of thermal light field within the coherence time may not be
the same as the one of laser light field within the coherence time.


title:
A sharp scattering condition for focusing mass-subcritical nonlinear
  Schr\"odinger equation

abstract:
  This article is concerned with time global behavior of solutions to focusing
mass-subcritical nonlinear Schr\"odinger equation of power type with data in a
critical homogeneous weighted $L^2$ space. We give a sharp sufficient condition
for scattering by proving existence of a threshold solution which does not
scatter at least for one time direction and of which initial data attains
minimum value of a norm of the weighted $L^2$ space in all initial value of
non-scattering solution. Unlike in the mass-critical or -supercritical case,
ground state is not a threshold. This is an extension of previous author's
result to the case where the exponent of nonlinearity is below so-called
Strauss number. A main new ingredient is a stability estimate in a
Lorenz-modified-Bezov type spacetime norm.


title: Block Sampling under Strong Dependence

abstract:
  The paper considers the block sampling method for long-range dependent
processes. Our theory generalizes earlier ones by Hall, Jing and Lahiri (1998)
on functionals of Gaussian processes and Nordman and Lahiri (2005) on linear
processes. In particular, we allow nonlinear transforms of linear processes.
Under suitable conditions on physical dependence measures, we prove the
validity of the block sampling method. The problem of estimating the
self-similar index is also studied.


title: Schwarzschild scalar wigs: spectral analysis and late time behavior

abstract:
  Using the Green's function representation technique, the late time behavior
of localized scalar field distributions on Schwarzschild spacetimes is studied.
Assuming arbitrary initial data we perform a spectral analysis, computing the
amplitude of each excited quasi-bound mode without the necessity of performing
dynamical evolutions. The resulting superposition of modes is compared with a
traditional numerical evolution with excellent agreement; therefore, we have an
efficient way to determine final black hole wigs. The astrophysical relevance
of the quasi-bound modes is discussed in the context of scalar field dark
matter models and the axiverse.


title:
Effects of the spin-orbital coupling on the vacancy-induced magnetism on
  the honeycomb lattice

abstract:
  The local magnetism induced by vacancies in the presence of the spin-orbital
interaction is investigated based on the half-filled Kane-Mele-Hubbard model on
the honeycomb lattice. Using the self-consistent mean-field theory, we find
that the spin-orbital coupling will enhance the localization of the spin
moments near a single vacancy. We further study the magnetic structures along
the zigzag edges formed by a chain of vacancies. We find that the spin-orbital
coupling tends to suppress the counter-polarized ferrimagnetic order on the
upper and lower edges, because of the open of the spin-orbital gap. As a
result, in the case of the balance number of sublattices, it will suppress
completely this kind of ferrimagnetic order. But, for the imbalance case, a
ferrimagnetic order along both edges exists because additional zero modes will
not be affected by the spin-orbital coupling.


title:
Concentration behavior of standing waves for almost mass critical
  nonlinear Schr\"{o}dinger equations

abstract:
  We study the following nonlinear Schr\"{o}dinger equation $$ iu_t=-\Delta
u+V(x)u-a|u|^qu \quad (t,x)\in \mathbb{R}^1\times \mathbb{R}^2, $$ where $a>0,
\ q\in(0,2)$ and $V(x)$ is some type of trapping potentials. For any fixed
$a>a^*:= \|Q\|_2^2$, where $Q$ is the unique (up to translations) positive
radial solution of $\Delta u-u+u^3=0$ in $\mathbb{R}^2$, by directly using
constrained variational method and energy estimates we present a detailed
analysis of the concentration and symmetry breaking of the standing waves for
the above equation as $q\nearrow 2$.


title:
Second order theory of $(j,0)\oplus (0,j)$ single high spins as Lorentz
  tensors

abstract:
  We show that higher order differential equations and matrix spinor calculus
are completely avoidable in the description of pure high spin-$j$ Weinberg-Joos
states, $(j,0)\oplus (0,j)$. The case is made on the example of
$(3/2,0)\oplus(0,3/2)$, for the sake of concreteness and without loss of
generality. Namely, we use as a vehicle for the aforementioned covariant single
spin-$3/2$ description the antisymmetric tensor of second rank with Dirac
spinor components, $\Psi_{[\mu\nu]}=B_{[\mu\nu]}\otimes\psi$. The
$(3/2,0)\oplus(0,3/2)$ sector of interest is tracked down in two steps. First
we search for spin-$3/2$ by means of a covariant spin projector constructed
from the Casimir invariants of the Poincar\'e algebra, and then we identify the
wanted irreducible representation space by means of a momentum independent
(static) projector designed on the basis of the Casimir invariants of the
Lorentz algebra. The latter projectors unambiguously identify any irreducible
$so(1,3)$ subspace of any Lorentz tensor and without rising the order of the
differential equation. The method proposed correctly reproduces the
electromagnetic multipole moments earlier calculated for single spin-$3/2$
particles in treating it in the standard way as eight dimensional spinor. We
furthermore calculate Compton scattering off the pure spin-$3/2$ under
discussion, and show that the differential cross section satisfies unitarity in
forward direction for a gyromagnetic ratio of $g=2/3$. Suggesting possible
validity of Belinfante's conjecture for pure spin-states, while the natural
value of $g=2$ seems more likely to characterize the highest spins in the
Rarita-Schwinger representation spaces. The scheme straightforwardly extends to
any $(j,0)\oplus (0,j)$ Weinberg-Joos state and brings the advantage of
avoiding rectangular matrix couplings between states of different spins,
replacing them by simple Lorentz contractions.


title:
Stochastic heat engine with the consideration of inertial effects and
  shortcuts to adiabaticity

abstract:
  When a Brownian particle in contact with a heat bath at a constant
temperature is controlled by a time-dependent harmonic potential, its
distribution function can be rigorously derived from the Kramers equation with
the consideration of the inertial effect of the Brownian particle. Based on
this rigorous solution and the concept of shortcuts to adiabaticity, we
construct a stochastic heat engine by employing the time-dependent harmonic
potential to manipulate the Brownian particle to complete a thermodynamic
cycle. We find that the efficiency at maximum power of this stochastic heat
engine is equal to $1-\sqrt{T_c/T_h}$ where $T_c$ and $T_h$ are the
temperatures of the cold bath and the hot one in the thermodynamic cycle,
respectively.


title: Unsupervised Pretraining Encourages Moderate-Sparseness

abstract:
  It is well known that direct training of deep neural networks will generally
lead to poor results. A major progress in recent years is the invention of
various pretraining methods to initialize network parameters and it was shown
that such methods lead to good prediction performance. However, the reason for
the success of pretraining has not been fully understood, although it was
argued that regularization and better optimization play certain roles. This
paper provides another explanation for the effectiveness of pretraining, where
we show pretraining leads to a sparseness of hidden unit activation in the
resulting neural networks. The main reason is that the pretraining models can
be interpreted as an adaptive sparse coding. Compared to deep neural network
with sigmoid function, our experimental results on MNIST and Birdsong further
support this sparseness observation.


title:
Optimal parameter selection for unsupervised neural network using
  genetic algorithm

abstract:
  K-means Fast Learning Artificial Neural Network (K-FLANN) is an unsupervised
neural network requires two parameters: tolerance and vigilance. Best
Clustering results are feasible only by finest parameters specified to the
neural network. Selecting optimal values for these parameters is a major
problem. To solve this issue, Genetic Algorithm (GA) is used to determine
optimal parameters of K-FLANN for finding groups in multidimensional data.
K-FLANN is a simple topological network, in which output nodes grows
dynamically during the clustering process on receiving input patterns. Original
K-FLANN is enhanced to select winner unit out of the matched nodes so that
stable clusters are formed with in a less number of epochs. The experimental
results show that the GA is efficient in finding optimal values of parameters
from the large search space and is tested using artificial and synthetic data
sets.


title: Cosmological Magnetogenesis From Extra-dimensional Gauss Bonnet Gravity

abstract:
  Generation of primordial magnetic fields during inflation typically requires
the breaking of conformal invariance of the Electromagnetic action. In this
paper this has been achieved naturally in a higher dimensional cosmological
model with a Gauss-Bonnet term in the action. The evolution of the scale factor
of the extra dimension (whose dynamics is influenced by the Gauss-Bonnet term)
acts as the cause for the breaking of conformal invariance. Different cases
have been investigated, each of which is characterized by the number of higher
dimensions, the value of the Gauss-Bonnet parameter, and the cosmological
constant. Many of the scenarios considered are highly constrained by the
requirements that the cosmic evolution is stable, that the normal dimensions
expand and that there is no back reaction due to growing electric fields.
However there do exist scenarios which satisfy the above requirements and are
well suited for magnetogenesis. In particular, a scenario where the number of
extra dimensions $D=4$ and the cosmological constant is non-zero, turns out to
be best suited for generating primordial magnetic fields. It is shown that for
these values of parameters, a scale invariant magnetic field of the order of
$10^{-10}-10^{-9}$ $G$ can be produced. Even in these most favorable scenarios,
the higher dimensional space expands during inflation at the same rate as the
normal dimension. Hence if a mechanism could freeze the evolution of the higher
dimension, this seems to be a viable mechanism to produce acceptable primordial
magnetic fields.


title: Variation of the solar magnetic flux spectrum during solar cycle 23

abstract:
  By using the unique database of SOHO/MDI full disk magnetograms from 1996
September to 2011 January, covering the entire solar cycle 23, we analyze the
time-variability of the solar magnetic flux spectrum and study the properties
of extended minimum of cycle 23. We totally identify 11.5 million magnetic
structures. It has been revealed that magnetic features with different magnetic
fluxes exhibit different cycle behaviors. The magnetic features with flux
larger than $4.0 \times 10^{19}$ Mx, which cover solar active regions and
strong network features, show exactly the same variation as sunspots; However,
the remaining $82\%$ magnetic features which cover the majority of network
elements show anti-phase variation with sunspots. We select a riterion that the
monthly sunspot number is less than 20 to represent the Sun's low activity
status. Then we find the extended minimum of cycle 23 is characterized by the
long duration of low activity status, but the magnitude of magnetic flux in
this period is not lower than previous cycle. Both the duration of low activity
status and the minimum activity level defined by minimum sunspot number show a
century period approximately. The extended minimum of cycle 23 shows
similarities with solar cycle 11, which preceded the mini-maxima in later solar
cycles. This similarity is suggestive that the solar cycles following cycle 23
are likely to have low activity.


title:
Exploring Regional Development of Digital Humanities Research: A Case
  Study for Taiwan

abstract:
  This study analyzed references and source papers of the Proceedings of
2009-2012 International Conference of Digital Archives and Digital Humanities
(DADH), which was held annually in Taiwan. A total of 59 sources and 1,104
references were investigated, based on descriptive analysis and subject
analysis of library practices on cataloguing. Preliminary results showed
historical materials, events, bureaucracies, and people of Taiwan and China in
the Qing Dynasty were the major subjects in the tempo-spatial dimensions. The
subject-date figure depicted a long-low head and short-high tail curve, which
demonstrated both characteristics of research of humanities and application of
technology in digital humanities. The dates of publication of the references
spanned over 360 years, which shows a long time span in research materials. A
majority of the papers (61.41%) were single-authored, which is in line with the
common research practice in the humanities. Books published by general
publishers were the major type of references, and this was the same as that of
established humanities research. The next step of this study will focus on the
comparison of characteristics of both sources and references of international
journals with those reported in this article.


title:
Enhancing the three-dimensional electronic structure in 1111-type iron
  arsenide superconductors by H-substitution

abstract:
  The 1111-type iron arsenide hydride CaFe1-xCoxAsH was synthesized by
high-pressure solid-state reaction, and its electronic structure and
superconducting properties were investigated. Bulk superconductivity was
observed at x = 0.07-0.26. A maximum superconducting critical temperature Tcmax
of 23 K was observed at x = 0.07. These values are in agreement with those of
CaFe1-xCoxAsF. The calculated Fermi surface of CaFeAsH has a small
three-dimensional 3D hole pocket around the Gamma point. This is a result of
weak covalent bonding between the As 4p and H 1s orbitals. No such covalency
exists in CaFeAsF, because the energy level of the F 2p orbital is sufficiently
deep to inhibit overlap with the As 4p orbital. The similar superconducting
properties of CaFe1-xCoxAsH and CaFe1-xCoxAsF are explained on the nesting
scenario. The small 3D hole pocket of CaFe1-xCoxAsH does not significantly
contribute to electron excitation. These findings encourage exploration of
hydrogen-containing 1111-type iron-based materials with lower anisotropies and
higher Tc applicable to superconducting wires and tapes.


title:
Tunable non-equilibrium Luttinger liquid based on counter-propagating
  edge channels

abstract:
  We investigate energy transfer between counter-propagating quantum Hall edge
channels (ECs) in a two-dimensional electron system at filling factor \nu=1.
The ECs are separated by a thin impenetrable potential barrier and Coulomb
coupled, thereby constituting a quasi one-dimensional analogue of a spinless
Luttinger liquid (LL). We drive one, say hot, EC far from thermal equilibrium
and measure the energy transfer rate P into the second, cold, EC using a
quantum point contact as a bolometer. The dependence of P on the drive bias
indicates breakdown of the momentum conservation, whereas P is almost
independent on the length of the region where the ECs interact. Interpreting
our results in terms of plasmons (collective density excitations), we find that
the energy transfer between the ECs occurs via plasmon backscattering at the
boundaries of the LL. The backscattering probability is determined by the LL
interaction parameter and can be tuned by changing the width of the
electrostatic potential barrier between the ECs.


title:
A log-free zero-density estimate and small gaps in coefficients of
  $L$-functions

abstract:
  Let $L(s, \pi\times\pi^\prime)$ be the Rankin--Selberg $L$-function attached
to automorphic representations $\pi$ and $\pi^\prime$. Let $\tilde{\pi}$ and
$\tilde{\pi}^\prime$ denote the contragredient representations associated to
$\pi$ and $\pi^\prime$. Under the assumption of certain upper bounds for
coefficients of the logarithmic derivatives of $L(s, \pi\times\tilde{\pi})$ and
$L(s, \pi^\prime\times\tilde{\pi}^\prime)$, we prove a log-free zero-density
estimate for $L(s, \pi\times\pi^\prime)$ which generalises a result due to
Fogels in the context of Dirichlet $L$-functions. We then employ this log-free
estimate in studying the distribution of the Fourier coefficients of an
automorphic representation $\pi$. As an application we examine the
non-lacunarity of the Fourier coefficients $b_f(p)$ of a modular newform
$f(z)=\sum_{n=1}^{\infty} b_f(n) e^{{2\pi i n z}}$ of weight $k$, level $N$,
and character $\chi$. More precisely for $f(z)$ and a prime $p$, set
$j_f(p):=\max_{x;~x> p} J_{f} (p, x)$, where $J_{f} (p, x):=\#\{{\rm
prime}~q;~a_{\pi}(q)=0~{\rm for~all~}p<q\leq x\}.$ We prove that $j_f(p)\ll_{f,
\theta} p^\theta$ for some $0<\theta<1$.


title: The face-on disk of MAXI J1836-194

abstract:
  We present Very Large Telescope optical spectra of the black hole candidate
X-ray binary MAXI J1836-194 at the onset of its 2011 outburst. Although the
spectrum was taken at the beginning of the outburst and contains a significant
contribution from the optically-thin synchrotron emission that originates in
the radio jet, we find that the accretion disk was already large and bright.
Single-peaked, narrow H$\alpha$ and He II $\lambda$4686 lines imply the most
face-on accretion disk observed in a black hole low-mass X-ray binary to date,
with an inclination angle between 4$^{\circ}$ and 15$^{\circ}$, assuming a
black hole mass of between 5 M$_\odot$ and 12 M$_\odot$, for distances of
between 4 and 10 kpc. We use New Technology Telescope observations of the
system in quiescence to place strong upper limits on the mass and radius of the
donor star and the orbital period. The donor is a main sequence star with a
mass < 0.65 M$_{\odot}$ and a radius < 0.59 R$_{\odot}$ with an orbital period
of < 4.9 hours. From those values and Roche lobe geometry constraints we find
that the compact object must be >1.9 M$_{\odot}$ if the system is located 4 kpc
away and >7.0 M$_{\odot}$ at 10 kpc.


title:
The accretion-ejection coupling in the black hole candidate X-ray binary
  MAXI J1836-194

abstract:
  We present the results of our quasi-simultaneous radio, sub-mm, infrared,
optical and X-ray study of the Galactic black hole candidate X-ray binary MAXI
J1836-194 during its 2011 outburst. We consider the full multi-wavelength
spectral evolution of the outburst, investigating whether the evolution of the
jet spectral break (the transition between optically-thick and optically-thin
synchrotron emission) is caused by any specific properties of the accretion
flow. Our observations show that the break does not scale with the X-ray
luminosity or with the inner radius of the accretion disk, and is instead
likely to be set by much more complex processes. We find that the radius of the
acceleration zone at the base of the jet decreases from ~10$^6$ gravitational
radii during the hard intermediate state to ~10$^3$ gravitational radii as the
outburst fades (assuming a black hole mass of 8 M$_{\odot}$), demonstrating
that the electrons are accelerated on much larger scales than the radius of the
inner accretion disk and that the jet properties change significantly during
outburst. From our broadband modelling and high-resolution optical spectra, we
argue that early in the outburst, the high-energy synchrotron cooling break was
located in the optical band, between $\approx 3.2 \times 10^{14}$ Hz and $4.5
\times 10^{14}$ Hz. We calculate that the jet has a total radiative power of
$\approx 3.1 \times 10^{36}$ ergs s$^{-1}$, which is ~6% of the bolometric
radiative luminosity at this time. We discuss how this cooling break may evolve
during the outburst, and how that evolution dictates the total jet radiative
power. Assuming the source is a stellar-mass black hole with canonical state
transitions, from the measured flux and peak temperature of the disk component
we constrain the source distance to be 4-10 kpc.


title:
Lorentz space estimates for vector fields with divergence and curl in
  Hardy spaces

abstract:
  In this note, we establish the estimate on the Lorentz space $L(3/2,1)$ for
vector fields in bounded domains under the assumption that the normal or the
tangential component of the vector fields on the boundary vanishing. We prove
that the $L(3/2,1)$ norm of the vector field can be controlled by the norms of
its divergence and curl in the atomic Hardy spaces and the $L^1$ norm of the
vector field itself.


title:
Atmospheric Modelling for the Removal of Telluric Features from Infrared
  Planetary Spectra

abstract:
  The effects of telluric absorption on infrared spectra present a problem for
the observer. Strong molecular absorptions from species whose concentrations
vary with time can be particularly challenging to remove precisely. Yet
removing these effects is key to accurately determining the composition of many
astronomical objects, planetary atmospheres in particular. Here we present a
method for removing telluric effects based on a modelling approach. The method
relies only on observations usually made by the planetary astronomer, and so is
directly comparable with current techniques. We use the modelling approach to
process observations made of Jupiter, and Saturnian moon Titan and compare the
results with those of the standard telluric division technique, finding the
modelling approach to have distinct advantages even in conditions regarded as
ideal for telluric division.


title:
Self-truncated ionization injection and consequent monoenergetic
  electron bunches in laser wakefield acceleration

abstract:
  The ionization-induced injection in laser wakefield acceleration has been
recently demonstrated to be a promising injection scheme. However, the energy
spread controlling in this mechanism remains a challenge because continuous
injection in a mixed gas target is usually inevitable. Here we propose that by
use of certain initially unmatched laser pulses, the electron injection can be
constrained to the very front region of the mixed gas target, typically in a
length of a few hundreds micro meters determined by laser-driven bubble
deformation. Under some optimized conditions, the injection region is well
limited within $200\rm \mu m$ and the electron beam with central energy of 383
MeV, energy spread of 3.33% in FWHM, normalized emittance of 3.12 mm mrad and
charge of 14.58 pC can be obtained according to particle-in-cell simulations.
Both multi-dimensional simulations and theoretical analysis illustrate the
effectiveness of this scheme.


title:
Molecular dynamics simulations of cumulative helium bombardments on
  tungsten surfaces

abstract:
  Molecular dynamics (MD) simulations were performed to study the cumulative
bombardments of low-energy (60-200 eV) helium (He) atoms on tungsten (W)
surfaces. The behaviour of He and the response of the W surface were
investigated. The He incident energy and tungsten temperature play important
roles on the formation and growth of He clusters. The temperature can promote
the coalescence of He clusters and increase the size of the He clusters. A
stratification phenomenon of the He depth distribution has been observed. The
rupture of the He clusters and, at the same time, the escape and re-deposition
of the W atoms have been observed. During the formation of He clusters, the
interstitial W atoms are produced and evolve into bundles of <111> crowdions,
which would be constrained around the He clusters for a long time. However,
they will finally move onto the top surface along the <111> direction, which
results in stacking the W atoms on the surface. The complex combination effects
of the He clusters and the interstitial atoms result in the growth of the
surfaces.


title:
A Hidden Markov Model of atomic quantum jump dynamics in an optically
  probed cavity

abstract:
  We analyze the quantum jumps of an atom interacting with a cavity field. The
strong atom- field interaction makes the cavity transmission depend on the time
dependent atomic state, and we present a Hidden Markov Model description of the
atomic state dynamics which is conditioned in a Bayesian manner on the detected
signal. We suggest that small variations in the observed signal may be due to
spatial motion of the atom within the cavity, and we represent the atomic
system by a number of hidden states to account for both the small variations
and the internal state jump dynamics. In our theory, the atomic state is
determined in a Bayesian manner from the measurement data, and we present an
iterative protocol, which determines both the atomic state and the model
parameters. As a new element in the treatment of observed quantum systems, we
employ a Bayesian approach that conditions the atomic state at time t on the
data acquired both before and after t and we show that the state assignment by
this approach is more decisive than the usual conditional quantum states, based
on only earlier measurement data.


title: SU(2s+1) symmetry and nonlinear dynamic equations of spin s magnets

abstract:
  The article is devoted to the description of dynamics of magnets with
arbitrary spin on the basis of the Hamiltonian formalism. The relationship
between the magnetic ordering and Poisson bracket subalgebras of the magnetic
degrees of freedom for spin s=1/2; 1; 3/2 has been established. We have been
obtained non-linear dynamic equations without damping for normal and degenerate
non-equilibrium states of high-spin magnets with the properties of the SO(3),
SU(4), SU(2)$\times$SU(2), SU(3), SO(4), SO(5) symmetry of exchange
interaction. The connection between models of the magnetic exchange energy and
the Casimir invariants has been discussed.


title:
Steady 3D viscous compressible flows with adiabatic exponent $\gamma\in
  (1,\infty)$

abstract:
  The Navier-Stokes equations for compressible barotropic flow in the
stationary three dimensional case are considered. It is assumed that a fluid
occupies a bounded domain and satisfies the no-slip boundary condition. The
existence of a weak solution under the assumption that the adiabatic exponent
satisfies $\gamma>1$ is proved. These results cover the cases of monoatomic,
diatomic, and polyatomic gases.


title:
An Introduction to Socially Connected Machines: Characteristics and
  Applications

abstract:
  Due to the development of information and communication technologies, it is
difficult to handle the billions of connected machines. In this paper, to cope
with the problem, we introduce machine social networks, where they freely
follow each other and share common interests with their neighbors. We classify
characteristics and describe required functionalities of socially connected
machines. We also illustrate two examples; a twit-bot and maze scenario.


title:
Micrometer-Thin Crystalline-Silicon Solar Cells Integrating Numerically
  Optimized 2-D Photonic Crystals

abstract:
  A 2-D photonic crystal was integrated experimentally into a thin-film
crystalline-silicon solar cell of 1-{\mu}m thickness, after numerical
optimization maximizing light absorption in the active material. The photonic
crystal boosted the short-circuit current of the cell, but it also damaged its
open-circuit voltage and fill factor, which led to an overall decrease in
performances. Comparisons between modeled and actual optical behaviors of the
cell, and between ideal and actual morphologies, show the global robustness of
the nanostructure to experimental deviations, but its particular sensitivity to
the conformality of the top coatings and the spread in pattern dimensions,
which should not be neglected in the optical model. As for the electrical
behavior, the measured internal quantum efficiency shows the strong parasitic
absorptions from the transparent conductive oxide and from the back-reflector,
as well as the negative impact of the nanopattern on surface passivation. Our
exemplifying case, thus, illustrates and experimentally confirms two
recommendations for future integration of surface nanostructures for light
trapping purposes: 1) the necessity to optimize absorption not for the total
stack but for the single active material, and 2) the necessity to avoid damage
to the active material by pattern etching.


title: On the Lowey length of modules of finite projective dimension

abstract:
  Let $(A,\mathfrak{m})$ be a local Gorenstein local ring and let $M$ be an $A$
module of finite length and finite projective dimension. We prove that the
Lowey length of $M$ is greater than or equal to order of $A$. This generalizes
a result of Avramov, Buchweitz, Iyengar and Miller


title: Single and double changes of Entanglement

abstract:
  Entanglement behavior for different classes of two qubit systems passing
through a generalized amplitude damping channel is discussed. The phenomena of
sudden single, double changes and the sudden death of entanglement are reported
for correlated and non- correlated noise. It is shown that, for less entangled
states, these phenomena appear for small values of channel strength. The effect
of the channel can be frozen for these classes as one increases the channel
strength. Maximum entangled states are more fragile than partial entangled
states, where the entanglement decays very fast. However, one can not freeze
the effect of the noise channel for systems initially prepared in maximum
entangled states. The decay rate of entanglement for systems affected by
non-correlated noise is much larger than that affected by correlated noise.


title: Risk-Sensitive Control and an Abstract Collatz-Wielandt Formula

abstract:
  The "value" of infinite horizon risk-sensitive control is the principal
eigenvalue of a certain positive operator. This facilitates the use of Chang's
extension of the Collatz-Wielandt formula to derive a variational
characterization thereof. For the uncontrolled case, this reduces to the
Donsker-Varadhan functional.


title: Electron assisted $dd$ reactions in metals

abstract:
  The electron assisted low energy $dd$ reactions in deuterized metals are
investigated. It is shown that if a metal is irradiated with slow, free
deuterons then the $e+d+d\rightarrow e^{\prime }+p+t$ and $e+d+d\rightarrow
e^{\prime }+n+$ $^{3}He$\ electron assisted $dd$ processes will have measurable
probabilities even in the case of slow deuterons. The cross sections and the
yields in an irradiated sample are determined. The results are associated with
the so called anomalous screening effect. It is concluded that the electron
$dd$ processes have to be taken into account when evaluating the experimental
data of low energy fusion reactions in metals.


title:
Global solutions for a nonlocal Ginzberg-Landau equation and a nonlocal
  Fokker-Plank equation

abstract:
  This work is devoted to the study of a nonlocal Ginzberg-Landau equation by
the semigroup method and a nonlocal Fokker-Plank equation by the viscosity
vanishing method. For the nonlocal Ginzberg-Landau equation, there exists a
unique global solution in the set
$C^0(\mathbb{R}^+,\,H_0^{\frac{\alpha}{2}}(D))\cap
L_{loc}(\mathbb{R}^+,\,H_0^{\alpha}(D))$, for $\alpha\in (0,\,2)$. For the
nonlocal Fokker-Plank equation, the regularity of the solution is weaker than
that of the nonlocal Ginzberg-Landau equation due to the drift term.


title:
Generation of Coherent Extreme-Ultraviolet Radiation Carrying Orbital
  Angular Momentum

abstract:
  We propose an effective scheme for the generation of intense coherent extreme
ultraviolet light beams carrying orbital angular momentum (OAM). The light is
produced by a high-gain harmonic-generation free-electron laser (FEL), seeded
using a laser pulse with a transverse staircase-like phase pattern. During
amplification, diffraction and mode selection drive the radiation profile
towards a dominant OAM mode at saturation. With a seed laser at 260 nm,
gigawatt power levels are obtained at wavelengths approaching those of soft
x-rays. Compared to other proposed schemes to generate OAM with FELs, our
approach is robust, easier to implement, and can be integrated into already
existing FEL facilities without extensive modifications of the machine layout.


title: Higgs bundles on weighted projective lines and loop crystals

abstract:
  We consider the space of nilpotent Higgs bundles on a weighted projective
line, as a global analog of the nilpotent cone. We show that it is pure,
compute its dimension, and define geometric correspondences between irreducible
components. We prove it by constructing a loop analog of a cristal, in the
spirit of Kashiwara and Saito, for some corresponding loop Kac-Moody algebra.


title: Model selection in a sparse heterogeneous framework

abstract:
  We consider a Gaussian sequence space model $X_{\lambda}=f_{\lambda} +
\xi_{\lambda},$ where $\xi $ has a diagonal covariance matrix
$\Sigma=\diag(\sigma_\lambda ^2)$. We consider the situation where the
parameter vector $(f_{\lambda})$ is sparse. Our goal is to estimate the unknown
parameter by a model selection approach. The heterogenous case is much more
involved than the direct model. Indeed, there is no more symmetry inside the
stochastic process that one needs to control since each empirical coefficient
has its own variance. The problem and the penalty do not only depend on the
number of coefficients that one selects, but also on their position. This
appears also in the minimax bounds where the worst coefficients will go to the
larger variances. However, with a careful and explicit choice of the penalty we
are able to select the correct coefficients and get a sharp non-asymptotic
control of the risk of our procedure. Some simulation results are provided.


title: Gravitational wave from rotating neutron star

abstract:
  Using the nuclear equation of states for a large variety of relativistic and
non-relativistic force parameters, we calculate the static and rotating masses
and radii of neutron stars. From these equation of states, we also evaluate the
properties of rotating neutron stars, such as rotational and gravitational
frequencies, moment of inertia, quadrupole deformation parameter, rotational
ellipcity and gravitational wave strain amplitude. The estimated gravitational
wave strain amplitude of the star is found to be $\sim 10^{-23}$.


title: Fisher Information and the Fourth Moment Theorem

abstract:
  Using a representation of the score function by means of the divergence
operator we exhibit a sufficient condition, in terms of the negative moments of
the norm of the Malliavin derivative, under which convergence in Fisher
information to the standard Gaussian of sequences belonging to a given Wiener
chaos is actually equivalent to convergence of only the fourth moment. Thus,
our result may be considered as a further building block associated to the
recent but already rich literature dedicated to the Fourth Moment Theorem of
Nualart and Peccati. To illustrate the power of our approach we prove a local
limit theorem together with some rates of convergence for the normal
convergence of a standardized version of the quadratic variation of the
fractional Brownian motion.


title:
The scaling limit of uniform random plane maps, via the Ambj{\o}rn-Budd
  bijection

abstract:
  We prove that a uniform rooted plane map with n edges converges in
distribution after a suitable normalization to the Brownian map for the
Gromov-Hausdorff topology. A recent bijection due to Ambj{\o}rn and Budd allows
to derive this result by a direct coupling with a uniform random
quadrangulation with n faces.


title: Naked singularity explosion in higher-dimensional dust collapse

abstract:
  In the context of the large extra dimensions or TeV-scale gravity, it has
been argued that an effective naked singularity, called the visible border of
spacetime, would be generated by high-energy particle collisions. Motivated by
this interesting possibility, we investigate a particle creation by a naked
singularity in general dimensions, adopting a spherically symmetric
self-similar dust collapse as the simple model of a naked singularity
formation. The power and energy of the particle emission behave in two distinct
ways depending on a parameter in the model. In a generic case, the emission
power is proportional to the quadratic inverse of the remaining time to the
Cauchy horizon, which has been known for the four-dimensional case in the
literature. On the other hand, in a degenerate case the emission power is
proportional to the quartic inverse of the remaining time to the Cauchy
horizon, and depends on the total mass of a dust fluid in spite that the
central region of the collapse is scale-free due to the self-similarity. In the
both cases, within a test-field approximation the energy radiated before any
quantum gravitational effect dominates amounts to TeV. This suggests that a
backreaction is not ignorable in the TeV-scale gravity context, in contrast to
the similar phenomena in stellar collapse.


title:
Topology of surfaces for molecular Stark energy, alignment and
  orientation generated by combined permanent and induced electric dipole
  interactions

abstract:
  We show that combined permanent and induced electric dipole interactions of
polar and polarizable molecules with collinear electric fields lead to a sui
generis topology of the corresponding Stark energy surfaces and of other
observables - such as alignment and orientation cosines - in the plane spanned
by the permanent and induced dipole interaction parameters. We find that the
loci of the intersections of the surfaces can be traced analytically and that
the eigenstates as well as the number of their intersections can be
characterized by a single integer index. The value of the index, distinctive
for a particular ratio of the interaction parameters, brings out a close
kinship with the eigenproperties obtained previously for a class of Stark
states via the apparatus of supersymmetric quantum mechanics.

categories: physics.chem-ph physics.atm-clus physics.atom-ph quant-ph


title:
Competitive Learning with Feedforward Supervisory Signal for Pre-trained
  Multilayered Networks

abstract:
  We propose a novel learning method for multilayered neural networks which
uses feedforward supervisory signal and associates classification of a new
input with that of pre-trained input. The proposed method effectively uses rich
input information in the earlier layer for robust leaning and revising internal
representation in a multilayer neural network.


title: CKVul: evolving nebula and three curious background stars

abstract:
  We analyse the remnants of CK Vul (Nova Vul 1670) using optical imaging and
spectroscopy. The imaging, obtained between 1991 and 2010, spans 5.6% of the
life-time of the nebula. The flux of the nebula decreased during the last 2
decades. The central source still maintains the ionization of the innermost
part of the nebula, but recombination proceeds in more distant parts of the
nebula. Surprisingly, we discovered two stars located within 10 arcsec of the
expansion centre of the radio emission that are characterized by pronounced
long term variations and one star with high proper motion. The high proper
motion star is a foreground object, and the two variable stars are background
objects. The photometric variations of two variables are induced by a dusty
cloud ejected by CK Vul and passing through the line of sight to those stars.
The cloud leaves strong lithium absorption in the spectra of the stars. We
discuss the nature of the object in terms of recent observations.


title: Deep learning for neuroimaging: a validation study

abstract:
  Deep learning methods have recently made notable advances in the tasks of
classification and representation learning. These tasks are important for brain
imaging and neuroscience discovery, making the methods attractive for porting
to a neuroimager's toolbox. Success of these methods is, in part, explained by
the flexibility of deep learning models. However, this flexibility makes the
process of porting to new areas a difficult parameter optimization problem. In
this work we demonstrate our results (and feasible parameter ranges) in
application of deep learning methods to structural and functional brain imaging
data. We also describe a novel constraint-based approach to visualizing high
dimensional data. We use it to analyze the effect of parameter choices on data
transformations. Our results show that deep learning methods are able to learn
physiologically important representations and detect latent relations in
neuroimaging data.


title:
Oscillatory matrix model in Chern-Simons theory and Jacobi-theta
  determinantal point process

abstract:
  The partition function of the Chern-Simons theory on the three-sphere with
the unitary group $U(N)$ provides a one-matrix model. The corresponding
$N$-particle system can be mapped to the determinantal point process whose
correlation kernel is expressed by using the Stieltjes-Wigert orthogonal
polynomials. The matrix model and the point process are regarded as
$q$-extensions of the random matrix model in the Gaussian unitary ensemble and
its eigenvalue point process, respectively. We prove the convergence of the
$N$-particle system to an infinite-dimensional determinantal point process in
$N \to \infty$, in which the correlation kernel is expressed by Jacobi's theta
functions. We show that the matrix model obtained by this limit realizes the
oscillatory matrix model in Chern-Simons theory discussed by de Haro and Tierz.

categories: math-ph cond-mat.stat-mech hep-th math.MP math.PR nlin.SI


title:
Two-pion low-energy contribution to the muon $g-2$ with improved
  precision from analyticity and unitarity

abstract:
  The two-pion contribution from low energies to the muon magnetic moment
anomaly, although small, has a large relative uncertainty since in this region
the experimental data on the cross sections are neither sufficient nor precise
enough. It is therefore of interest to see whether the precision can be
improved by means of additional theoretical information on the pion
electromagnetic form factor, which controls the leading order contribution. In
the present paper we address this problem by exploiting analyticity and
unitarity of the form factor in a parametrization-free approach that uses the
phase in the elastic region, known with high precision from the Fermi-Watson
theorem and Roy equations for $\pi\pi$ elastic scattering as input. The
formalism also includes experimental measurements on the modulus in the region
0.65-0.70 GeV, taken from the most recent $e^+e^-\to \pi^+\pi^-$ experiments,
and recent measurements of the form factor on the spacelike axis. By combining
the results obtained with inputs from CMD2, SND, BABAR and KLOE, we make the
predictions $a_\mu^{\pi\pi, \LO}\,[2 m_\pi,\, 0.30 \gev]=(0.553 \pm 0.004)
\times 10^{-10}$ and $a_\mu^{\pi\pi, \LO}\,[0.30 \gev,\, 0.63 \gev]=(133. 083
\pm 0.837)\times 10^{-10}$. These are consistent with the other recent
determinations, and have slightly smaller errors.


title:
The $b$-adic tent transformation for quasi-Monte Carlo integration using
  digital nets

abstract:
  In this paper we investigate quasi-Monte Carlo (QMC) integration using
digital nets over $\mathbb{Z}_b$ in reproducing kernel Hilbert spaces. The tent
transformation, or the baker's transformation, was originally used for lattice
rules by Hickernell (2002) to achieve higher order convergence of the
integration error for smooth non-periodic integrands, and later, has been
successfully applied to digital nets over $\mathbb{Z}_2$ by Cristea et al.
(2007) and Goda (2014). The aim of this paper is to generalize the latter two
results to digital nets over $\mathbb{Z}_b$ for an arbitrary prime $b$. For
this purpose, we introduce the {\em $b$-adic tent transformation} for an
arbitrary positive integer $b$ greater than 1, which is a generalization of the
original (dyadic) tent transformation. Further, again for an arbitrary positive
integer $b$ greater than 1, we analyze the mean square worst-case error of QMC
rules using digital nets over $\mathbb{Z}_b$ which are randomly digitally
shifted and then folded using the $b$-adic tent transformation in reproducing
kernel Hilbert spaces. Using this result, for a prime $b$, we prove the
existence of good higher order polynomial lattice rules over $\mathbb{Z}_b$
among the smaller number of candidates as compared to the result by Dick and
Pillichshammer (2007), which achieve almost the optimal convergence rate of the
mean square worst-case error in unanchored Sobolev spaces of smoothness of
arbitrary high order.


title: Fast Training of Convolutional Networks through FFTs

abstract:
  Convolutional networks are one of the most widely employed architectures in
computer vision and machine learning. In order to leverage their ability to
learn complex functions, large amounts of data are required for training.
Training a large convolutional network to produce state-of-the-art results can
take weeks, even when using modern GPUs. Producing labels using a trained
network can also be costly when dealing with web-scale datasets. In this work,
we present a simple algorithm which accelerates training and inference by a
significant factor, and can yield improvements of over an order of magnitude
compared to existing state-of-the-art implementations. This is done by
computing convolutions as pointwise products in the Fourier domain while
reusing the same transformed feature map many times. The algorithm is
implemented on a GPU architecture and addresses a number of related challenges.


title: On injective resolutions of local cohomology modules

abstract:
  Let $K$ be a field of characteristic zero and let $R = K[X_1,\ldots,X_n]$.
Let $I$ be an ideal in $R$ and let $M = H^i_I(R)$ be the $i^{th}$-local
cohomology module of $R$ with respect to $I$.
  Let $c = \ injdim \ M$. We prove that if $P$ is a prime ideal in $R$ with
Bass number $\mu_c(P,M) > 0$ then $P$ is a maximal ideal in $R$.


title: Multi-GPU Training of ConvNets

abstract:
  In this work we evaluate different approaches to parallelize computation of
convolutional neural networks across several GPUs.


title:
Disks in a narrow channel jammed by gravity and centrifuge: profiles of
  pressure, mass density and entropy density

abstract:
  This work investigates jammed granular matter under conditions that produce
heterogeneous mass distributions on a mesoscopic scale. We consider a system of
identical disks that are confined to a narrow channel, open at one end and
closed off at the other end. The disks are jammed by the local pressure in a
gravitational field or centrifuge. All surfaces are hard and frictionless. We
calculate the profiles of pressure, mass density, and entropy density on a
mesoscopic length scale under the assumption that the jammed states are
produced by random agitations of uniform intensity along the channel. These
profiles exhibit trends and features governed by the balancing of
position-dependent forces and potential energies. The analysis employs a method
of configurational statistics that uses interlinking two-disk tiles as the
fundamental degrees of freedom. Configurational statistics weighs the
probabilities of tiles according to competing potential energies associated
with gravity and centrifugation. Amendments account for the effects of the
marginal stability of some tiles due to competing forces.