title:
Extra-Nuclear Starbursts: Young Luminous Hinge Clumps in Interacting
  Galaxies

abstract:
  Hinge clumps are luminous knots of star formation near the base of tidal
features in some interacting galaxies. We use archival Hubble Space Telescope
UV/optical/IR images and Chandra X-ray maps along with GALEX UV, Spitzer IR,
and ground-based optical/near-IR images to investigate the star forming
properties in a sample of 12 hinge clumps in five interacting galaxies. The
most extreme of these hinge clumps have star formation rates of 1 - 9
M(sun)/yr, comparable to or larger than the `overlap' region of intense star
formation between the two disks of the colliding galaxy system the Antennae. In
the HST images, we have found remarkably large (~70 pc) and luminous (M(I) ~
12.2 to -16.5) sources at the centers of these hinge clumps, sometimes embedded
in a linear ridge of fainter star clusters. We have found strong X-ray emission
from several of these hinge clumps. In most cases, this emission is
well-resolved with Chandra and has a thermal X-ray spectrum, thus it is likely
due to hot gas associated with the star formation. The ratio of the
extinction-corrected diffuse X-ray luminosity to the mechanical energy rate
(the X-ray production efficiency) for the hinge clumps is similar to that in
the Antennae galaxies, but higher than those for regions in the normal spiral
galaxy NGC 2403. Two of the hinge clumps have point-like X-ray emission much
brighter than expected for hot gas; these sources are likely `ultra-luminous
X-ray sources' (ULXs) due to accretion disks around black holes. The most
extreme of these sources, in Arp 240, has a hard X-ray spectrum and an absorbed
X-ray luminosity of ~2 X 10^41 erg/s; more than expected by single high mass
X-ray binaries (HMXBs), thus it may be either a collection of HMXBs or an
intermediate-mass black hole (>=80 M(sun)). [ abridged ]


title:
An interior penalty discontinuous Galerkin method for a class of
  monotone quasilinear elliptic problems

abstract:
  A family of interior penalty $hp$-discontinuous Galerkin methods is developed
and analyzed for the numerical solution of the quasilinear elliptic equation
$-\nabla{} \cdot (\mathbf{A}(\nabla{u}) \nabla{u} = f$ posed on the open
bounded domain $\Omega \subset \mathbb{R}^d$, $d \geq 2$. Subject to the
assumption that the map $\mathbf{v} \mapsto \mathbf{A}(\mathbf{v}) \mathbf{v}$,
$\mathbf{v} \in \mathbb{R}^d$, is Lipschitz continuous and strongly monotone,
it is proved that the proposed method is well-posed. \emph{A priori} error
estimates are presented of the error in the broken $H^1(\Omega)$-norm,
exhibiting precisely the same $h$-optimal and mildly $p$-suboptimal convergence
rates as obtained for the interior penalty approximation of linear elliptic
problems. \emph{A priori} estimates for linear functionals of the error and the
$L^2(\Omega)$-norm of the error are also established and shown to be
$h$-optimal for a particular member of the proposed family of methods. The
analysis is completed under fairly weak conditions on the approximation space,
allowing for non-affine and curved elements with multilevel hanging nodes. The
theoretical results are verified by numerical experiments.


title:
Optimal Random Access and Random Spectrum Sensing for an Energy
  Harvesting Cognitive Radio with and without Primary Feedback Leveraging

abstract:
  We consider a secondary user (SU) with energy harvesting capability. We
design access schemes for the SU which incorporate random spectrum sensing and
random access, and which make use of the primary automatic repeat request (ARQ)
feedback. We study two problem-formulations. In the first problem-formulation,
we characterize the stability region of the proposed schemes. The sensing and
access probabilities are obtained such that the secondary throughput is
maximized under the constraints that both the primary and secondary queues are
stable. Whereas in the second problem-formulation, the sensing and access
probabilities are obtained such that the secondary throughput is maximized
under the stability of the primary queue and that the primary queueing delay is
kept lower than a specified value needed to guarantee a certain quality of
service (QoS) for the primary user (PU). We consider spectrum sensing errors
and assume multipacket reception (MPR) capabilities. Numerical results show the
enhanced performance of our proposed systems.


title:
The effect of helium accretion efficiency on rates of Type Ia
  supernovae: double-detonations in accreting binaries

abstract:
  The double-detonation explosion scenario of Type Ia supernovae has gained
increased support from the SN Ia community as a viable progenitor model, making
it a promising candidate alongside the well-known single degenerate and double
degenerate scenarios. We present delay times of double-detonation SNe, in which
a sub-Chandrasekhar mass carbon-oxygen white dwarf accretes non-dynamically
from a helium-rich companion. One of the main uncertainties in quantifying SN
rates from double-detonations is the (assumed) retention efficiency of He-rich
matter. Therefore, we implement a new prescription for the treatment of
accretion/accumulation of He-rich matter on white dwarfs. In addition, we test
how the results change depending on which criteria are assumed to lead to a
detonation in the helium shell. In comparing the results to our standard case
(Ruiter et al. 2011), we find that regardless of the adopted He accretion
prescription, the SN rates are reduced by only 25% if low-mass He shells (<
0.05 Msun) are sufficient to trigger the detonations. If more massive (0.1
Msun) shells are needed, the rates decrease by 85% and the delay time
distribution is significantly changed in the new accretion model - only SNe
with prompt (< 500 Myr) delay times are produced. Since theoretical arguments
favour low-mass He shells for normal double-detonation SNe, we conclude that
the rates from double-detonations are likely to be high, and should not
critically depend on the adopted prescription for accretion of He.


title: On the complexity of computing the $k$-metric dimension of graphs

abstract:
  Given a connected graph $G=(V,E)$, a set $S\subseteq V$ is a $k$-metric
generator for $G$ if for any two different vertices $u,v\in V$, there exist at
least $k$ vertices $w_1,...,w_k\in S$ such that $d_G(u,w_i)\ne d_G(v,w_i)$ for
every $i\in \{1,...,k\}$. A metric generator of minimum cardinality is called a
$k$-metric basis and its cardinality the $k$-metric dimension of $G$. We study
some problems regarding the complexity of some $k$-metric dimension problems.
For instance, we show that the problem of computing the $k$-metric dimension of
graphs is $NP$-Complete. However, the problem is solved in linear time for the
particular case of trees.


title:
Comparison of some properties of star forming galaxies and active
  galactic nuclei (AGNs) between two BOSS galaxy samples of SDSS DR9

abstract:
  Using the LOWZ and CMASS samples of the ninth data release (DR9) from the
SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS), I investigate
properties of star forming galaxies and AGNs. The CMASS sample seriously
suffers from the radial selection effect, even within the redshift 0.44<z<0.6,
which will lead to statistical conclusions in the CMASS sample being less
likely robust. In the LOWZ sample, the fraction of star-forming galaxies is
nearly constant from the lowest density regime to the densest regime; the AGN
fraction is also insensitive to the local environment. In addition, I note that
in the LOWZ sample, stellar mass and stellar velocity dispersion distributions
of star forming galaxies and AGNs are nearly same.


title:
Environmental dependence of different colors in the CMASS sample of the
  SDSS DR9

abstract:
  In this study, I investigate the environmental dependence of galaxy colors in
the CMASS sample of the Sloan Digital Sky Survey Data Release 9 (SDSS DR9). To
decrease the radial selection effect, I divide the CMASS sample into subsamples
with a redshift binning size of 0.01 and analyze the environmental dependence
of the u-r, u-g, g-r, r-i and i-z colors for these subsamples in each redshift
bin. Statistical analysis shows that all the five colors weakly correlate with
the local environment, which may mean that the environmental processes
responsible for a galaxy's properties proceed slowly over cosmic time.


title: A note on $L^p$-norms of quasi-modes

abstract:
  In this note we show how improved $L^p$-estimates for certain types of
quasi-modes are naturally equaivalent to improved operator norms of spectral
projection operators associated to shrinking spectral intervals of the
appropriate scale. Using this, one can see that recent estimates that were
stated for eigenfunctions also hold for the appropriate types of quasi-modes.


title:
Optical control of cardiac cell excitability based on two-photon
  infrared absorption of AzoTAB

abstract:
  Recent studies of AzoTAB activity in excitable cell cultures have shown that
this substance is able to control excitability depending on isomer, cis or
trans, predominating in the cellular membrane. Control of isomerization can be
performed noninvasively by UV-visual radiation. At the same time it is
well-known that azobenezenes can be effectively transformed from one isomer
into another by two-photon absorption. Current work is devoted to the study of
trans-AzoTAB two-photon transformation in aqueous solution and inside primal
neonatal contractive rat cardiomyocytes. In accordance with results obtained
Azo-TAB can be used as a probe for two-photon optical control of cardiac
excitability.


title:
Distributed Iterative Detection Based on Reduced Message Passing for
  Networked MIMO Cellular Systems

abstract:
  This paper considers base station cooperation (BSC) strategies for the uplink
of a multi-user multi-cell high frequency reuse scenario where distributed
iterative detection (DID) schemes with soft/hard interference cancellation
algorithms are studied. The conventional distributed detection scheme exchanges
{soft symbol estimates} with all cooperating BSs. Since a large amount of
information needs to be shared via the backhaul, the exchange of hard bit
information is preferred, however a performance degradation is experienced. In
this paper, we consider a reduced message passing (RMP) technique in which each
BS generates a detection list with the probabilities for the desired symbol
that are sorted according to the calculated probability. The network then
selects the best {detection candidates} from the lists and conveys the index of
the constellation symbols (instead of double-precision values) among the
cooperating cells. The proposed DID-RMP achieves an inter-cell-interference
(ICI) suppression with low backhaul traffic overhead compared with {the
conventional soft bit exchange} and outperforms the previously reported
hard/soft information exchange algorithms.


title:
The impossibility of obfuscation with auxiliary input or a universal
  simulator

abstract:
  In this paper we show that the existence of general indistinguishability
obfuscators conjectured in a few recent works implies, somewhat
counterintuitively, strong impossibility results for virtual black box
obfuscation. In particular, we show that indistinguishability obfuscation for
all circuits implies:
  * The impossibility of average-case virtual black box obfuscation with
auxiliary input for any circuit family with super-polynomial pseudo-entropy.
Such circuit families include all pseudo-random function families, and all
families of encryption algorithms and randomized digital signatures that
generate their required coin flips pseudo-randomly. Impossibility holds even
when the auxiliary input depends only on the public circuit family, and not the
specific circuit in the family being obfuscated.
  * The impossibility of average-case virtual black box obfuscation with a
universal simulator (with or without any auxiliary input) for any circuit
family with super-polynomial pseudo-entropy.
  These bounds significantly strengthen the impossibility results of Goldwasser
and Kalai (STOC 2005).


title: Hyperkahler Sigma Model and Field Theory on Gibbons-Hawking Spaces

abstract:
  We describe a novel deformation of the 3-dimensional sigma model with
hyperk\"ahler target, which arises naturally from the compactification of a
4-dimensional $\mathcal{N}=2$ theory on a hyperk\"ahler circle bundle
(Gibbons-Hawking space). We derive the condition for which the deformed sigma
model preserves 4 out of the 8 supercharges. We also study the contribution
from a NUT center to the sigma model path integral, and find that supersymmetry
implies it is a holomorphic section of a certain holomorphic line bundle over
the hyperk\"ahler target. We study explicitly the case where the original
4-dimensional theory is pure $U(1)$ super Yang-Mills, and show that the
contribution from a NUT center in this case is simply the Jacobi theta
function.


title: A simplicial approach to effective divisors in $\overline{M}_{0,n}$

abstract:
  We study the Cox ring and monoid of effective divisor classes of
$\overline{M}_{0,n} = Bl\mathbb{P}^{n-3}$, over a ring R. We provide a
bijection between elements of the Cox ring, not divisible by any exceptional
divisor section, and pure-dimensional singular simplicial complexes on
{1,...,n-1} with nonzero weights in R satisfying a zero-tension condition. This
leads to a combinatorial criterion, satisfied by many triangulations of closed
manifolds, for a divisor class to be among the minimal generators for the
effective monoid. For classes obtained as the strict transform of quadrics, we
present a complete classification of minimal generators, generalizing to all n
the well-known Keel-Vermeire classes for n=6. We use this classification to
construct new divisors with interesting properties for all n > 6.


title: On Second Order Elliptic and Parabolic Equations of Mixed Type

abstract:
  It is known that solutions to second order uniformly elliptic and parabolic
equations, either in divergence or nondivergence (general) form, are H\"{o}lder
continuous and satisfy the interior Harnack inequality. We show that even in
the one-dimensional case ($x\in R^1$), these properties are not preserved for
equations of mixed divergence-nondivergence structure: for elliptic equations.
\begin{equation*}
  D_i(a^1_{ij}D_ju)+a^2_{ij}D_{ij}u=0, \end{equation*} and parabolic equations
\begin{equation*} p\partial_t u=D_i(a_{ij}D_ju), \end{equation*} where
$p=p(t,x)$ is a bounded strictly positive function. The H\"{o}lder continuity
and Harnack inequality are known if $p$ does not depend either on $t$ or on
$x$. We essentially use homogenization techniques in our construction.
Bibliography: 23 titles.


title: Hyperkahler metric and GMN ansatz on focus-focus fibrations

abstract:
  In this paper, we study hyperkahler metric and practice GMN's construction of
hyperkahler metric on focus-focus fibrations. We explicitly compute the
action-angel coordinates on the local model of focus-focus fibration, and show
its semi-global invariant should be harmonic to admit a compatible holomorphic
2-form. Then we study the canonical semi-flat metric on it. After the instanton
correction, finally we get a re-construction of the generalized Ooguri-Vafa
metric.


title: Gravitation and the noise needed in objective reduction models

abstract:
  I briefly recall intersections of my research interests with those of John
Bell. I then argue that the noise needed in theories of objective state vector
reduction most likely comes from a fluctuating complex part in the classical
spacetime metric, that is, state vector reduction is driven by {\it complex
number valued} "spacetime foam".


title: Sandpile models

abstract:
  This survey is an extended version of lectures given at the Cornell
Probability Summer School 2013. The fundamental facts about the Abelian
sandpile model on a finite graph and its connections to related models are
presented. We discuss exactly computable results via Majumdar and Dhar's
method. The main ideas of Priezzhev's computation of the height probabilities
in 2D are also presented, including explicit error estimates involved in
passing to the limit of the infinite lattice. We also discuss various questions
arising on infinite graphs, such as convergence to a sandpile measure, and
stabilizability of infinite configurations.


title:
Improving the Load Balance of MapReduce Operations based on the Key
  Distribution of Pairs

abstract:
  Load balance is important for MapReduce to reduce job duration, increase
parallel efficiency, etc. Previous work focuses on coarse-grained scheduling.
This study concerns fine-grained scheduling on MapReduce operations. Each
operation represents one invocation of the Map or Reduce function. Scheduling
MapReduce operations is difficult due to highly screwed operation loads, no
support to collect workload statistics, and high complexity of the scheduling
problem. So current implementations adopt simple strategies, leading to poor
load balance. To address these difficulties, we design an algorithm to schedule
operations based on the key distribution of intermediate pairs. The algorithm
involves a sub-program for selecting operations for task slots, and we name it
the Balanced Subset Sum (BSS) problem. We discuss properties of BSS and design
exact and approximation algorithms for it. To transparently incorporate these
algorithms into MapReduce, we design a communication mechanism to collect
statistics, and a pipeline within Reduce tasks to increase resource
utilization. To the best of our knowledge, this is the first work on scheduling
MapReduce workload at this fine-grained level. Experiments on PUMA [T+12]
benchmarks show consistent performance improvement. The job duration can be
reduced by up to 37%, compared with standard MapReduce.


title: Vacuum alignment and lattice artifacts: Wilson fermions

abstract:
  Confinement in asymptotically free gauge theories is accompanied by the
spontaneous breaking of the global flavor symmetry. If a subgroup of the flavor
symmetry group is coupled weakly to additional gauge fields, the vacuum state
tends to align such that the gauged subgroup is unbroken. Independently, a
lattice discretization of the continuum theory typically reduces the manifest
flavor symmetry, and, in addition, can give rise to new lattice-artifact phases
with spontaneously broken symmetries. Here, we study the interplay of these two
phenomena for Wilson fermions, using chiral lagrangian techniques. We consider
two examples: electromagnetic corrections to QCD, and a prototype
composite-Higgs model.


title: On Thompson's group T and algebraic K-theory

abstract:
  Using a theorem of L\"uck-Reich-Rognes-Varisco, we show that the Whitehead
group of Thompson's group T is infinitely generated, even when tensored with
the rationals. To this end we describe the structure of the centralizers and
normalizers of the finite cyclic subgroups of T, via a direct geometric
approach based on rotation numbers. This also leads to an explicit computation
of the source of the Farrell-Jones assembly map for the rationalized higher
algebraic K-theory of the integral group ring of T.


title:
The WiggleZ Dark Energy Survey: Improved Distance Measurements to z = 1
  with Reconstruction of the Baryonic Acoustic Feature

abstract:
  We present significant improvements in cosmic distance measurements from the
WiggleZ Dark Energy Survey, achieved by applying the reconstruction of the
baryonic acoustic feature technique. We show using both data and simulations
that the reconstruction technique can often be effective despite patchiness of
the survey, significant edge effects and shot-noise. We investigate three
redshift bins in the redshift range 0.2<$z$<1, and in all three find
improvement after reconstruction in the detection of the baryonic acoustic
feature and its usage as a standard ruler. We measure model independent
distance measures $D_{\mathrm V}(r_{\mathrm s}^\mathrm{fid}/r_{\mathrm s})$ of
1716 $\pm$ 83 Mpc, 2221 $\pm$ 101 Mpc, 2516 $\pm$ 86 Mpc (68% CL) at effective
redshifts z = 0.44, 0.6, 0.73, respectively, where $D_{\mathrm V}$ is the
volume-average-distance, and $r_{\mathrm s}$ is the sound horizon at the end of
the baryon drag epoch. These significantly improved 4.8, 4.5 and 3.4 percent
accuracy measurements are equivalent to those expected from surveys with up to
2.5 times the volume of WiggleZ. These measurements are fully consistent with
cosmologies allowed by the analyses of the Planck Collaboration and the Sloan
Digital Sky Survey.We provide the $D_{\mathrm V}(r_{\mathrm
s}^\mathrm{fid}/r_{\mathrm s})$ posterior probability distributions and their
covariances. When combining these measurements with temperature fluctuations
measurements of Planck, the polarization of WMAP9, and the 6dF Galaxy Survey
baryonic acoustic feature, we do not detect deviations from a flat LCDM model.
Assuming this model we constrain the current expansion rate to $H_0$ = 67.15
$\pm$ 0.98 kms$^{-1}$Mpc$^{-1}$. Allowing the equation of state of dark energy
to vary we obtain $w_\mathrm{DE}$ = -1.080 $\pm$ 0.135. When assuming a curved
LCDM model we obtain a curvature value of $\Omega_{\mathrm K}$ = -0.0043 $\pm$
0.0047.


title: Tight Bounds for Active Self-Assembly Using an Insertion Primitive

abstract:
  We prove two tight bounds on the behavior of a model of self-assembling
particles introduced by Dabby and Chen (SODA 2013), called insertion systems,
where monomers insert themselves into the middle of a growing linear polymer.
First, we prove that the expressive power of these systems is equal to
context-free grammars, answering a question posed by Dabby and Chen. Second, we
prove that systems of $k$ monomer types can deterministically construct
polymers of length $n = 2^{\Theta(k^{3/2})}$ in $O(\log^{5/3}(n))$ expected
time, and that this is optimal in both the number of monomer types and expected
time.


title: Gaussian bounds, strong ellipticity and uniqueness criteria

abstract:
  Let $h$ be a quadratic form with domain $W_0^{1,2}(\Ri^d)$ given by \[
h(\varphi)=\sum^d_{i,j=1}(\partial_i\varphi,c_{ij}\,\partial_j\varphi) \] where
$c_{ij}=c_{ji}$ are real-valued, locally bounded, measurable functions and
  $C=(c_{ij})\geq 0 $.
  If $C$ is strongly elliptic, i.e.\ if there exist $\lambda, \mu>0$ such that
$\lambda\,I\geq C\geq \mu \,I>0$, then $h$ is closable, the closure determines
a positive self-adjoint operator $H$ on $L_2(\Ri^d)$ which generates a
submarkovian semigroup $S$ with a positive distributional kernel~$K$ and the
kernel satisfies Gaussian upper and lower bounds. Moreover, $S$ is
conservative, i.e.\ $S_t\one=\one$ for all $t>0$. Our aim is to examine
converse statements.
  First we establish that $C$ is strongly elliptic if and only if $h$ is
closable, the semigroup $S$ is conservative and $K$ satisfies Gaussian bounds.
Secondly, we prove that if the coefficients are such that a Tikhonov growth
condition is satisfied then $S$ is conservative. Thus in this case strong
ellipticity of $C$ is equivalent to closability of $h$ together with Gaussian
bounds on $K$. Finally we consider coefficients $c_{ij}\in W^{1,\infty}_{\rm
loc}(\Ri^d)$. It follows that $h$ is closable and a growth condition of the
T\"acklind type is sufficient to establish the equivalence of strong
ellipticity of $C$ and Gaussian bounds on $K$.


title:
Quasi-Quantum Planes and Quasi-Quantum Groups of Dimension $p^3$ and
  $p^4$

abstract:
  The aim of this paper is to contribute more examples and classification
results of finite pointed quasi-quantum groups within the quiver framework
initiated in \cite{qha1, qha2}. The focus is put on finite dimensional graded
Majid algebras generated by group-like elements and two skew-primitive elements
which are mutually skew-commutative. Such quasi-quantum groups are associated
to quasi-quantum planes in the sense of nonassociative geomertry \cite{m1, m2}.
As an application, we obtain an explicit classification of graded pointed Majid
algebras with abelian coradical of dimension $p^3$ and $p^4$ for any prime
number $p.$


title: EigenGP: Gaussian Process Models with Adaptive Eigenfunctions

abstract:
  Gaussian processes (GPs) provide a nonparametric representation of functions.
However, classical GP inference suffers from high computational cost for big
data. In this paper, we propose a new Bayesian approach, EigenGP, that learns
both basis dictionary elements--eigenfunctions of a GP prior--and prior
precisions in a sparse finite model. It is well known that, among all
orthogonal basis functions, eigenfunctions can provide the most compact
representation. Unlike other sparse Bayesian finite models where the basis
function has a fixed form, our eigenfunctions live in a reproducing kernel
Hilbert space as a finite linear combination of kernel functions. We learn the
dictionary elements--eigenfunctions--and the prior precisions over these
elements as well as all the other hyperparameters from data by maximizing the
model marginal likelihood. We explore computational linear algebra to simplify
the gradient computation significantly. Our experimental results demonstrate
improved predictive performance of EigenGP over alternative sparse GP methods
as well as relevance vector machine.


title:
A novel determination of density, temperature and symmetry energy for
  nuclear multi-fragmentation through primary fragment yield reconstruction

abstract:
  For the first time primary hot isotope distributions are experimentally
reconstructed in intermediate heavy ion collisions and used with
antisymmetrized molecular dynamics (AMD) calculations to determine density,
temperature and symmetry energy coefficient in a self-consistent manner. A
kinematical focusing method is employed to reconstruct the primary hot fragment
yield distributions for multifragmentation events observed in the reaction
system $^{64}$Zn + $^{112}$Sn at 40 MeV/nucleon. The reconstructed yield
distributions are in good agreement with the primary isotope distributions of
AMD simulations. The experimentally extracted values of the symmetry energy
coefficient relative to the temperature, $a_{sym}/T$, are compared with those
of the AMD simulations with different density dependence of the symmetry energy
term. The calculated $a_{sym}/T$ values changes according to the different
interactions. By comparison of the experimental values of $a_{sym}/T$ with
those of calculations, the density of the source at fragment formation was
determined to be $\rho /\rho_{0} = (0.63 \pm 0.03 )$. Using this density, the
symmetry energy coefficient and the temperature are determined in a
self-consistent manner as $a_{sym} = (24.7 \pm 1.9) MeV$ and $T=(4.9 \pm 0.2)$
MeV


title:
Theoretical analysis of a Stochastic Approximation approach for
  computing Quasi-Stationary distributions

abstract:
  This paper studies a method, which has been proposed in the Physics
literature by [8, 7, 10], for estimating the quasi-stationary distribution. In
contrast to existing methods in eigenvector estimation, the method eliminates
the need for explicit transition matrix manipulation to extract the principal
eigenvector. Our paper analyzes the algorithm by casting it as a stochastic
approximation algorithm (Robbins-Monro) [23, 16]. In doing so, we prove its
convergence and obtain its rate of convergence. Based on this insight, we also
give an example where the rate of convergence is very slow. This problem can be
alleviated by using an improved version of the algorithm that is given in this
paper. Numerical experiments are described that demonstrate the effectiveness
of this improved method.


title: Progress on Light-Ion Fusion Reactions with Three-Nucleon Forces

abstract:
  The description of structural and dynamical properties of nuclei starting
from the fundamental interaction between nucleons has been a long-standing goal
in nuclear physics. The ab initio No-Core Shell Model combined with the
Resonating-Group Method (NCSM/RGM) is capable of addressing both structural and
reaction properties of light-nuclei. While promising results have already been
achieved starting from a two-body Hamiltonian, a truly realistic prediction of
nuclear observables requires the treatment of the three-nucleon interaction.
Using similarity-renormalization-group evolved two- and three-nucleon
interactions, we will present recent applications to n-4He scattering process
when accounting for the chiral two- plus three-nucleon interaction versus the
chiral two-nucleon interaction. We compare our results to phase shifts obtained
from R-matrix analysis of data up to 16 MeV neutron energy, below the d-3H
threshold.


title:
Quantitative Comparison Between Crowd Models for Evacuation Planning and
  Evaluation

abstract:
  Crowd simulation is rapidly becoming a standard tool for evacuation planning
and evaluation. However, the many crowd models in the literature are
structurally different, and few have been rigorously calibrated against
real-world egress data, especially in emergency situations. In this paper we
describe a procedure to quantitatively compare different crowd models or
between models and real-world data. We simulated three models: (1) the lattice
gas model, (2) the social force model, and (3) the RVO2 model, and obtained the
distributions of six observables: (1) evacuation time, (2) zoned evacuation
time, (3) passage density, (4) total distance traveled, (5) inconvenience, and
(6) flow rate. We then used the DISTATIS procedure to compute the compromise
matrix of statistical distances between the three models. Projecting the three
models onto the first two principal components of the compromise matrix, we
find the lattice gas and RVO2 models are similar in terms of the evacuation
time, passage density, and flow rates, whereas the social force and RVO2 models
are similar in terms of the total distance traveled. Most importantly, we find
that the zoned evacuation times of the three models to be very different from
each other. Thus we propose to use this variable, if it can be measured, as the
key test between different models, and also between models and the real world.
Finally, we compared the model flow rates against the flow rate of an emergency
evacuation during the May 2008 Sichuan earthquake, and found the social force
model agrees best with this real data.


title:
Experimental realization of photonic topological insulator in a uniaxial
  metacrystal waveguide

abstract:
  Achieving robust transport has attracted much attention in both electronic
and photonic systems. Time-reversal invariant photonic crystal can be employed
to realize backscattering-immune chiral state, but the chiral bandgap is
topologically trivial. Here, we designed and fabricated a metacrystal
comprising non-resonant meta-atoms sandwiched between two metallic plates and
the system exhibits topological phase transition as established by group
classification. The nontrivial bandgap was confirmed by experimentally measured
transmission spectra, calculated nonzero spin Chern number and Z2 index.
Gapless spin-filtered edge states were demonstrated experimentally by measuring
the magnitude and phase of the fields. The transpsort robustness of the edge
states were also observed when an obstacle is introduced near the edge.


title:
High energy particles with negative and positive energies in the
  vicinity of black holes

abstract:
  It is shown that the energy in the centre of mass frame of two colliding
particles in free fall at any point of the ergosphere of the rotating black
hole can grow without limit for fixed energy values of particles on infinity.
The effect takes place for large negative values of the angular momentum of one
of the particles. It occurs that the geodesics with negative energy in
equatorial plane of rotating black holes cannot originate or terminate inside
the ergosphere. Their length is always finite and this leads to conclusion that
they must originate and terminate inside the gravitational radius of the
ergosphere. The energy in the centre of mass frame of one particle falling into
the gravitational radius and the other arriving from the area inside it is
growing without limit on the horizon.


title:
Probing the metastability of protoneutron star with hyperon in
  core-collapse supernova

abstract:
  We investigate the role of hyperons in the dynamical collapse of a
non-rotating massive star to a black hole(BH) using one dimensional general
relativistic $GR1D$ code. We follow the dynamical formation and evolution of a
protoneutron star (PNS) to a black hole using various progenitor models,
adopting a hyperonic equation of state (EoS) generated by Shen et. al. We
compare the results with those of nuclear EoS by Shen et. al. and understand
the role of strange hyperons in the core collapse supernova. We discuss the
neutrino signals that may be used as a probe to core collapse. Further, an
exotic EoS can support a much lower maximum mass cold neutron star compared to
PNS. In this regard, we also study the metastability of PNS in the presence of
hyperon in the long-time evolution of the progenitors, relevant to supernova
SN1987A.


title:
Extended topological defects as sources and outlets of dislocations in
  spherical hexagonal crystals

abstract:
  Extended topological defects (ETDs) arising in spherical hexagonal crystals
due to their curvature are considered. These prevalent defects carry a unit
total topological charge and are surrounded by scalene pentagonal boundaries.
Topological peculiarities of reactions between ETDs and dislocations are
considered. Similarly to boundaries of the usual planar crystalline order the
ETDs emit and absorb the dislocations without preservation of their
dislocational charge. Dislocations located inside the ETD area lose it and the
enforced ETD decay can proceed in different ways without conservation of the
total Burgers vector of the dislocations emitted.


title:
Low temperature ordering in easy-axis $S=1$ kagome and triangular
  lattice antiferromagnets

abstract:
  A brief review is provided of earlier work on the low temperature phases of
$S=1$ kagome and triangular lattice antiferromagnets in which there is
sufficiently strongly single-ion anisotropy $D$ that dominates over the
antiferromagnetic exchange $J$.


title: Is $2k$-Conjecture valid for finite volume methods?

abstract:
  This paper is concerned with superconvergence properties of a class of finite
volume methods of arbitrary order over rectangular meshes. Our main result is
to prove {\it 2k-conjecture}: at each vertex of the underlying rectangular
mesh, the bi-$k$ degree finite volume solution approximates the exact solution
with an order
  $ O(h^{2k})$, where $h$ is the mesh size. As byproducts, superconvergence
properties for finite volume discretization errors at Lobatto and Gauss points
are also obtained. All theoretical findings are confirmed by numerical
experiments.


title: Microwave-driven Topological Resonant Excitations of Coupled Skyrmions

abstract:
  We study nonlinear dynamics of coupled Skyrmions and present a method for
manipulating topological resonant excitations by a dual-frequency microwave
field. Thiele's equation is extended by introducing a new effective mass
associated with time derivative of topological density. Two coupled resonant
modes endowed with the new effective mass are found in the coupled Skyrmions.
Polygon-like resonant excitations are observed and modulated when the two modes
are activated simultaneously by microwave field with commensurate frequency
ratio. Quasiperiodic behavior of excitations are related to an incommensurate
ratio. Numerical solutions based on the extended Thiele's equation for Skyrmion
under a dual-frequency field agree well with the micromagnetic simulation
results and clarify the importance of frequency value, frequency ratio of an
external field and the effective mass to the polygon-like dynamics of Skyrmion.
We also show the coupling between two Skyrmions can dominate their topological
resonant excitations.


title: Conformal symmetry of JIMWLK Evolution at NLO

abstract:
  We construct the Next to Leading Order JIMWLK Hamiltonian for high energy
evolution in ${\cal N}=4$ SUSY theory, and show that it possesses conformal
invariance, even though it is derived using sharp cutoff on rapidity variable.
The conformal transformation properties of Wilson lines are not quite the naive
ones, but at NLO acquire an additional anomalous piece. We construct explicitly
the inversion symmetry generator. We also show how to construct for every
operator $O$, including the Hamiltonian itself, its "conformal extension" $\cal
O$, such that it transforms under the inversion in the naive way.


title: Surprise(s) in magnets without net moments

abstract:
  We are all familiar with ferromagnetic and antiferromagnetic materials, in
which the localized ionic moments (in case of ionic insulators) or the
electronic spins (in case of metals) go into a long-range ordered state with a
net macroscopic moment (in case of ferromagnets) or a net macroscopic
sublattice magnetization (in case of antiferromagnets). However this behaviour
is far from ubiquitous even in ionic insulators with well-developed local
moments. Indeed, there are many ionic insulators in which the dominant
interactions between the local moments compete with each other, leading to a
cooperative paramagnetic state with no ordering of the moments down to the
lowest temperatures accessible to experiments. The physics of such magnets
without net moments has some interesting and surprising aspects, which are
touched upon in this brief review.


title: Generalization Bounds for Representative Domain Adaptation

abstract:
  In this paper, we propose a novel framework to analyze the theoretical
properties of the learning process for a representative type of domain
adaptation, which combines data from multiple sources and one target (or
briefly called representative domain adaptation). In particular, we use the
integral probability metric to measure the difference between the distributions
of two domains and meanwhile compare it with the H-divergence and the
discrepancy distance. We develop the Hoeffding-type, the Bennett-type and the
McDiarmid-type deviation inequalities for multiple domains respectively, and
then present the symmetrization inequality for representative domain
adaptation. Next, we use the derived inequalities to obtain the Hoeffding-type
and the Bennett-type generalization bounds respectively, both of which are
based on the uniform entropy number. Moreover, we present the generalization
bounds based on the Rademacher complexity. Finally, we analyze the asymptotic
convergence and the rate of convergence of the learning process for
representative domain adaptation. We discuss the factors that affect the
asymptotic behavior of the learning process and the numerical experiments
support our theoretical findings as well. Meanwhile, we give a comparison with
the existing results of domain adaptation and the classical results under the
same-distribution assumption.


title:
Giant zero field cooled spontaneous exchange bias effect in phase
  separated La1.5Sr0.5CoMnO6

abstract:
  We report a giant zero field cooled exchange bias (ZEB) effect (~0.65 T) in
La1.5Sr0.5CoMnO6 sample. Magnetic study has revealed a reentrant spin glass ~90
K, phase separation to spin glass and ferromagnetic phases below 50 K and
canted antiferromagnetic transition ~10 K. A small conventional exchange bias
(CEB) is established with the advent of spontaneous phase separation down to 10
K. Giant ZEB and enhanced CEB effects are found only below 10 K and are
attributed to the large unidirectional anisotropy at the interface of
isothermally field induced ferromagnetic phase and canted antiferromagnetic
background.


title:
On the cohomology and extensions of $n$-ary multiplicative Hom-Nambu-Lie
  superalgebras

abstract:
  In this paper, we discuss the representations of $n$-ary multiplicative
Hom-Nambu-Lie superalgebras as a generalization of the notion of
representations for $n$-ary multiplicative Hom-Nambu-Lie algebras. We also give
the cohomology of an $n$-ary multiplicative Hom-Nambu-Lie superalgebra and
obtain a relation between extensions of an $n$-ary multiplicative Hom-Nambu-Lie
superalgebra $\mathfrak{b}$ by an abelian one $\mathfrak{a}$ and
$Z^1(\mathfrak{b}, \mathfrak{a})_{\bar{0}}$. We also introduce the notion of
$T^*$-extensions of $n$-ary multiplicative Hom-Nambu-Lie superalgebras and
prove that every finite-dimensional nilpotent metric $n$-ary multiplicative
Hom-Nambu-Lie superalgebra $(\g,[\cdot,\cdots,\cdot]_{\g},\alpha,\langle
,\rangle_{\g})$ over an algebraically closed field of characteristic not 2 in
the case $\alpha$ is a surjection is isometric to a suitable $T^*$-extension.


title: Counting Terms in the Binary Lambda Calculus

abstract:
  In a paper entitled Binary lambda calculus and combinatory logic, John Tromp
presents a simple way of encoding lambda calculus terms as binary sequences. In
what follows, we study the numbers of binary strings of a given size that
represent lambda terms and derive results from their generating functions,
especially that the number of terms of size n grows roughly like 1.963447954^n.


title:
Thermally-assisted-occupation density functional theory with
  generalized-gradient approximations

abstract:
  We extend the recently proposed thermally-assisted-occupation density
functional theory (TAO-DFT) [J.-D. Chai, J. Chem. Phys. 136, 154104 (2012)] to
generalized-gradient approximation (GGA) exchange-correlation density
functionals. Relative to our previous TAO-LDA (i.e., the local density
approximation to TAO-DFT), the resulting TAO-GGAs are significantly superior
for a wide range of applications, such as thermochemistry, kinetics, and
reaction energies. For noncovalent interactions, TAO-GGAs with empirical
dispersion corrections are shown to yield excellent performance. Due to their
computational efficiency for systems with strong static correlation effects,
TAO-LDA and TAO-GGAs are applied to study the electronic properties (e.g., the
singlet-triplet energy gaps, vertical ionization potentials, vertical electron
affinities, fundamental gaps, and symmetrized von Neumann entropy) of acenes
with different number of linearly fused benzene rings (up to 100), which is
very challenging for conventional electronic structure methods. The ground
states of acenes are shown to be singlets for all the chain lengths studied
here. With the increase of acene length, the singlet-triplet energy gaps,
vertical ionization potentials, and fundamental gaps decrease monotonically,
while the vertical electron affinities and symmetrized von Neumann entropy
(i.e., a measure of polyradical character) increase monotonically.

categories: physics.chem-ph cond-mat.mtrl-sci cond-mat.str-el physics.atm-clus physics.comp-ph


title:
Electrolyte gate dependent high-frequency measurement of graphene
  field-effect transistor for sensing applications

abstract:
  We performed radiofrequency (RF) reflectometry measurements at 2.4 GHz on
electrolyte-gated graphene field-effect transistors (GFETs) utilizing a tunable
stub-matching circuit for impedance matching. We demonstrate that the gate
voltage dependent RF resistivity of graphene can be deduced even in the
presence of the electrolyte which is in direct contact with the graphene layer.
The RF resistivity is found to be consistent with its DC counterpart in the
full gate voltage range. Furthermore, in order to access the potential of
high-frequency sensing for applications, we demonstrate time-dependent gating
in solution with nanosecond time resolution.


title: A note on "A simple algorithm to search for all MCs in networks"

abstract:
  Recently, Yeh [Yeh, WC. (2006). A simple algorithm to search for all MCs in
networks. European Journal of Operational Research, 174, 1694{1705.] has
proposed a simple algorithm to find all the Minimal Cuts in an undirected
graph. However, the algorithm does not work properly. Here, using an example, a
defect of this algorithm is illustrated, and then the corresponding result is
shown to be incorrect. Moreover, a correct version of the algorithm is
established.


title:
Aging the Cu-doped Bi2Te3 crystals for the topological transport and its
  atomic tunneling-clustering dynamics

abstract:
  We report on the observation of the two-dimensional weak antilocalization in
(Cu0.1Bi0.9)2Te3.06 crystals relying on measurements of the magnetoresistance
in a tilted field. The dephasing analysis and scanning tunneling spectroscopy
corroborate the transport of the topological surface states (SS). The SSs
contribute 3.3% conductance in 30{\mu}m-thick material and become dominant in
the 100nm-thick flakes. Such optimized topological SS transport is achieved by
an intense aging process, when the bulk conductance is suppressed by four
orders of magnitude in the long period. Scanning tunneling microscopy reveals
that Cu atoms are initially inside the quintuple layers and migrate to the
layer gaps to form Cu clusters during the aging. In combination with
first-principles calculations, an atomic tunneling-clustering procedure across
a diffusion barrier of 0.57eV is proposed.


title: Fixing the Quantum Three-Point Function

abstract:
  We propose a new method for the computation of quantum three-point functions
for operators in su(2) sectors of N=4 super Yang-Mills theory. The method is
based on the existence of a unitary transformation relating inhomogeneous and
long-range spin chains. This transformation can be traced back to a combination
of boost operators and an inhomogeneous version of Baxter's corner transfer
matrix. We reproduce the existing results for the one-loop structure constants
in a simplified form and indicate how to use the method at higher loop orders.
Then we evaluate the one-loop structure constants in the quasiclassical limit
and compare them with the recent strong coupling computation.

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


title: Super-Sample Covariance in Simulations

abstract:
  Using separate universe simulations, we accurately quantify super-sample
covariance (SSC), the typically dominant sampling error for matter power
spectrum estimators in a finite volume, which arises from the presence of super
survey modes. By quantifying the power spectrum response to a background mode,
this approach automatically captures the separate effects of beat coupling in
the quasilinear regime, halo sample variance in the nonlinear regime and a new
dilation effect which changes scales in the power spectrum coherently across
the survey volume, including the baryon acoustic oscillation scale. It models
these effects at typically the few percent level or better with a handful of
small volume simulations for any survey geometry compared with directly using
many thousands of survey volumes in a suite of large volume simulations. The
stochasticity of the response is sufficiently small that in the quasilinear
regime, SSC can be alternately included by fitting the mean density in the
volume with these fixed templates in parameter estimation. We also test the
halo model prescription and find agreement typically at better than the 10%
level for the response.


title: Technical Notes on "A new approach to the d-MC problem"

abstract:
  System reliability is the probability of the maximum flow in a
stochastic-flow network from the source node to the sink node being more than a
demand level d. There are several approaches to compute system reliability
using upper boundary points, called d-MinCuts (d-MCs). Search for all the d-MCs
in a stochastic-flow network is an NP-hard problem. Here, a work proposed by
Yeh [Yeh WC. A new approach to the d-MC problem. Reliab Eng and Syst Saf 2002;
77(2): 201-206.] for determining all the d-MCs is investigated. Two results
(Lemma 3 and Theorem 5) are shown to be incorrect and their correct versions
are established. Also, the complexity result (Theorem 6) is shown to be
incorrect and the correct count is provided.


title:
Enhanced Sampling in Molecular Dynamics Using Metadynamics,
  Replica-Exchange, and Temperature-Acceleration

abstract:
  We review a selection of methods for performing enhanced sampling in
molecular dynamics simulations. We consider methods based on collective
variable biasing and on tempering, and offer both historical and contemporary
perspectives. In collective-variable biasing, we first discuss methods stemming
from thermodynamic integration that use mean force biasing, including the
adaptive biasing force algorithm and temperature acceleration. We then turn to
methods that use bias potentials, including umbrella sampling and metadynamics.
We next consider parallel tempering and replica-exchange methods. We conclude
with a brief presentation of some combination methods.


title:
On possible time singular points and eventual regularity of weak
  solutions to the fractional Navier-Stokes equations

abstract:
  In this paper, we intend to reveal how the fractional dissipation
$(-\Delta)^{\alpha}$ affects the regularity of weak solutions to the 3d
generalized Navier-Stokes equations. Precisely, it will be shown that the
$(5-4\alpha)/2\alpha$ dimensional Hausdorff measure of possible time singular
points of weak solutions on the interval $(0,\infty)$ is zero when
$5/6\le\alpha< 5/4$. To this end, the eventual regularity for the weak
solutions is firstly established in the same range of $\alpha$. It is worth
noting that when the dissipation index $\alpha$ varies from $5/6$ to $ 5/4$,
the corresponding Hausdorff dimension is from $1$ to $0$. Hence, it seems that
the Hausdorff dimension obtained is optimal. Our results rely on the fact that
the space $H^{\alpha}$ is the critical space or subcritical space to this
system when $\alpha\geq5/6$.


title: Grunwald- Wang Theorem, an Effective Version

abstract:
  The main purpose of this note is to establish an effective version of the
Grunwald--Wang Theorem, which asserts that given a family of local characters
$\chi^{v}$ of $K_{v}^{*}$ of exponent $m$ where $v \in S$ for a finite set $S$
of primes of $K$, there exists a global character $\chi$ of the idele class
group $C_{K}$ of exponent $m$ (unless some special case occurs, when it is $2
m$) whose component at $v$ is $\chi^{v}$. The effectiveness problem for this
theorem is to bound the norm $N (\chi)$ of the conductor of $\chi$ in terms of
$K$, $m$, $S$ and $N (\chi^{v})$.
  The Kummer case (when $K$ contains $\mu_{m}$) is easy since it is almost an
application of the Chinese Remainder Theorem. In this note, we solve this
problem completely in general case, and give three versions of bound, one is
with \GRH, and the other two are unconditional bounds.
  These effective results have some interesting applications in concrete
situations. To give a simple example, if we fix $p$ and $l$, one gets a good
least upper bound for $N$ such that $p$ is not an $l$--th power mod $N$. One
also gets the least upper bound for $N$ such that $l^{r} \mid \phi (N)$ and $p$
is not an $l$--th power mod $N$.
  Some part of this note is adopted (with some revision) from my unpublished
thesis (2001) (\cite{Wang2001}).


title: Multiplicity One Theorems, S-Version

abstract: We proved three theorems of $S$-version of the mulyiplicity one.


title:
Semileptonic decays $B_c^+\to D^{(*)}_{(s)}(l^+\nu,l^+l^-,\nu\bar\nu)$
  in the perturbative QCD approach

abstract:
  In this paper we study the semileptonic decays of $B_c^+\to
D^{(*)}_{(s)}(l^+\nu_l,l^+l^-,\nu\bar\nu)$ (here $l$ stands for $e$, $\mu$, or
$\tau$). After evaluating the $B_c^+ \to (D_{(s)},D^*_{(s)})$ transition form
factors $F_{0,+,T}(q^2)$ and $V(q^2), A_{0,1,2}(q^2), T_{1,2,3}(q^2)$ by
employing the perturbative QCD factorization approach, we calculate the
branching ratios for all these semileptonic decays. Our predictions for the
values of the $B_c^+ \to D_{(s)}$ and $B_c^+ \to D^*_{(s)}$ transition form
factors are consistent with those obtained by using other methods. The
branching ratios of the decay modes with $\bar\nu\nu$ are almost an order of
magnitude larger than the corresponding decays with $l^+l^-$ after the
summation over the three neutrino generations. The branching ratios for the
decays with $b\to d$ transitions are much smaller than those decays with the
$b\to s$ transitions, due to the Cabibbo-Kobayashi-Maskawa suppression. We
define ratios $R_D$ and $R_{D^*}$ for the branching ratios with the $\tau$
lepton versus $\mu$, $e$ lepton final states to cancel the uncertainties of the
form factors, which could possibly be tested in the near future.


title: Galaxy-wide outflows: cold gas and star formation at high speeds

abstract:
  Several active galaxies show strong evidence for fast ($v_{\rm out} \sim
1000~{\rm km\,s}^{-1}$) massive ($\dot{M} =$ several $\times 1000~\msun\,{\rm
yr}^{-1}$) gas outflows. Such outflows are expected on theoretical grounds once
the central supermassive black hole reaches the mass set by the $M - \sigma$
relation, and may be what makes galaxies become red and dead. Despite their
high velocities, which imply temperatures far above those necessary for
molecule dissociation, the outflows contain large amounts of molecular gas. To
understand this surprising result, we investigate the gas cooling and show that
the outflows cannot stably persist in high--temperature states. Instead the
outflowing gas forms a two--phase medium, with cold dense molecular clumps
mixed with hot tenuous gas, as observed. We also show that efficient cooling
leads to star formation, providing an observable outflow signature. The central
parts of the outflows can be intrinsically luminous gamma--ray sources,
provided that the central black hole is still strongly accreting. We note also
that these outflows can persist for $\sim 10^8$~yr after the central AGN has
turned off, so that many observed outflows (particularly with high speeds)
otherwise assumed to be driven by starbursts might also be of this type.


title:
Some field-theoretical aspects of two types of the Poincare group
  representations

abstract:
  The capabilities of some approaches to the relativistic description of
hadronic states with any rest spin are analysed. The key feature in the
Wigner's construction of irreducible representations of the Poincare group
which makes this construction fruitless in the particle physics is picked out.
A realization of unitary irreducible representations of the Poincare group of
the standard type, which yet have never been considered, is discussed. The
viability of the description of hadrons by the Poincare group representations
of the standard type in the space of the infinite-component ISFIR-class fields
is pointed out.


title:
Stationary configurations for the average distance functional and
  related problems

abstract:
  For a functional defined on the class of closed one-dimensional connected
subsets of ${\mathbb R}^n$ we consider the corresponding minimization problem
and we give suitable first order necessary conditions of optimality. The cases
studied here are the average distance functional arising in the mass
transportation theory, and the energy related to an elliptic PDE.


title:
Hybrid Approach to Face Recognition System using Principle component and
  Independent component with score based fusion process

abstract:
  Hybrid approach has a special status among Face Recognition Systems as they
combine different recognition approaches in an either serial or parallel to
overcome the shortcomings of individual methods. This paper explores the area
of Hybrid Face Recognition using score based strategy as a combiner/fusion
process. In proposed approach, the recognition system operates in two modes:
training and classification. Training mode involves normalization of the face
images (training set), extracting appropriate features using Principle
Component Analysis (PCA) and Independent Component Analysis (ICA). The
extracted features are then trained in parallel using Back-propagation neural
networks (BPNNs) to partition the feature space in to different face classes.
In classification mode, the trained PCA BPNN and ICA BPNN are fed with new face
image(s). The score based strategy which works as a combiner is applied to the
results of both PCA BPNN and ICA BPNN to classify given new face image(s)
according to face classes obtained during the training mode. The proposed
approach has been tested on ORL and other face databases; the experimented
results show that the proposed system has higher accuracy than face recognition
systems using single feature extractor.


title: Faster 3-Periodic Merging Networks

abstract:
  We consider the problem of merging two sorted sequences on a comparator
network that is used repeatedly, that is, if the output is not sorted, the
network is applied again using the output as input. The challenging task is to
construct such networks of small depth. The first constructions of merging
networks with a constant period were given by Kuty{\l}owski, Lory\'s and
Oesterdikhoff. They have given $3$-periodic network that merges two sorted
sequences of $N$ numbers in time $12\log N$ and a similar network of period $4$
that works in $5.67\log N$. We present a new family of such networks that are
based on Canfield and Williamson periodic sorter. Our $3$-periodic merging
networks work in time upper-bounded by $6\log N$. The construction can be
easily generalized to larger constant periods with decreasing running time, for
example, to $4$-periodic ones that work in time upper-bounded by $4\log N$.
Moreover, to obtain the facts we have introduced a new proof technique.


title: Equivariant lattice generators and Markov bases

abstract:
  It has been shown recently that monomial maps in a large class respecting the
action of the infinite symmetric group have, up to symmetry, finitely generated
kernels. We study the simplest nontrivial family in this class: the maps given
by a single monomial. Considering the corresponding lattice map, we explicitly
construct an equivariant lattice generating set, whose width (the number of
variables necessary to write it down) depends linearly on the width of the map.
This result is sharp and improves dramatically the previously known upper bound
as it does not depend on the degree of the image monomial. In the case of of
width two, we construct an explicit finite set of binomials generating the
toric ideal up to symmetry. Both width and degree of this generating set are
sharply bounded by linear functions in the exponents of the monomial.


title: Theory and Applications of Proper Scoring Rules

abstract:
  We give an overview of some uses of proper scoring rules in statistical
inference, including frequentist estimation theory and Bayesian model selection
with improper priors.


title: On rotational invariance of lattice Boltzmann schemes

abstract:
  We propose the derivation of acoustic-type isotropic partial differential
equations that are equivalent to linear lattice Boltzmann schemes with a
density scalar field and a momentum vector field as conserved moments. The
corresponding linear equivalent partial differential equations are generated
with a new "Berliner version" of the Taylor expansion method. The details of
the implementation are presented. These ideas are applied for the D2Q9, D2Q13,
D3Q19 and D3Q27 lattice Boltzmann schemes. Some limitations associated with
necessary stability conditions are also presented.


title:
On the Complexity of the Mis\`ere Version of Three Games Played on
  Graphs

abstract:
  We investigate the complexity of finding a winning strategy for the mis\`ere
version of three games played on graphs : two variants of the game
$\text{NimG}$, introduced by Stockmann in 2004 and the game $\text{Vertex
Geography}$ on both directed and undirected graphs. We show that on general
graphs those three games are $\text{PSPACE}$-Hard or Complete. For one
$\text{PSPACE}$-Hard variant of $\text{NimG}$, we find an algorithm to compute
an effective winning strategy in time $\mathcal{O}(\sqrt{|V(G)|}.|E(G)|)$ when
$G$ is a bipartite graph.


title: The Unified Surface Ricci Flow

abstract:
  Ricci flow deforms the Riemannian metric proportionally to the curvature,
such that the curvature evolves according to a heat diffusion process and
eventually becomes constant everywhere. Ricci flow has demonstrated its great
potential by solving various problems in many fields, which can be hardly
handled by alternative methods so far.
  This work introduces the unified theoretic framework for discrete Surface
Ricci Flow, including all common schemes: Thurston's Circle Packing, Tangential
Circle Packing, Inversive Distance Circle Packing and Discrete Yamabe.
Furthermore, this work also introduces a novel scheme, virtual radius circle
packing, under the unified framework. This work gives explicit geometric
interpretation to the discrete Ricci energy for all the schemes, and Hessian of
the discrete Ricci energy for schemes with Euclidean back ground geometry.
  The unified frame work deepen our understanding to the the discrete surface
Ricci flow theory, and inspired us to discover the new schemes, improved the
flexibility and robustness of the algorithms, greatly simplified the
implementation and improved the debugging efficiency. Experimental results
shows the unified surface Ricci flow algorithms can handle general surfaces
with different topologies, and is robust to meshes with different qualities,
and effective for solving real problems.


title: Effective Hamiltonians for fastly driven many-body lattice systems

abstract:
  We consider 1D lattices described by Hubbard or Bose-Hubbard models, in the
presence of periodic high-frequency perturbations, such as uniform ac force or
modulation of hopping coefficients. Effective Hamiltonians for interacting
particles are derived using an averaging method resembling classical canonical
perturbation theory. As is known, a high-frequency force may renormalize
hopping coefficients, causing interesting phenomena such as coherent
destruction of tunnelling and creation of artificial gauge fields. We find
explicitly additional corrections to the effective Hamiltonians due to
interactions, corresponding to non-trivial processes such as single-particle
density-dependent tunnelling, correlated pair hoppings, nearest neighbour
interactions, etc. Some of these processes arise also in multiband lattice
models, and are capable to give rise to a rich variety of quantum phases. The
apparent contradiction with other methods, e.g. Floquet-Magnus expansion, is
explained. The results may be useful for designing effective Hamiltonian models
in experiments with ultracold atoms, as well as in the field of ultrafast
nonequilibrium magnetism. An example of manipulating exchange interaction in a
Mott-Hubbard insulator is considered, where our corrections play an essential
role.


title: Torus manifolds and non-negative curvature

abstract:
  A torus manifold $M$ is a $2n$-dimensional orientable manifold with an
effective action of an $n$-dimensional torus such that $M^T\neq \emptyset$. In
this paper we discuss the classification of torus manifolds which admit an
invariant metric of non-negative curvature. If $M$ is a simply connected torus
manifold which admits such a metric, then $M$ is diffeomorphic to a quotient of
a free linear torus action on a product of spheres. We also classify rationally
elliptic torus manifolds $M$ with $H^{\text{odd}}(M;\mathbb{Z})=0$ up
homeomorphism.


title: Epitope profiling via mixture modeling of ranked data

abstract:
  We propose the use of probability models for ranked data as a useful
alternative to a quantitative data analysis to investigate the outcome of
bioassay experiments, when the preliminary choice of an appropriate
normalization method for the raw numerical responses is difficult or subject to
criticism. We review standard distance-based and multistage ranking models and
in this last context we propose an original generalization of the Plackett-Luce
model to account for the order of the ranking elicitation process. The
usefulness of the novel model is illustrated with its maximum likelihood
estimation for a real data set. Specifically, we address the heterogeneous
nature of experimental units via model-based clustering and detail the
necessary steps for a successful likelihood maximization through a hybrid
version of the Expectation-Maximization algorithm. The performance of the
mixture model using the new distribution as mixture components is compared with
those relative to alternative mixture models for random rankings. A discussion
on the interpretation of the identified clusters and a comparison with more
standard quantitative approaches are finally provided.


title:
Path-connectedness of the moduli spaces of metrics with positive
  isotropic curvature on four-manifolds

abstract:
  In this paper we prove the path connectedness of the moduli spaces of metrics
with positive isotropic curvature on certain compact four-dimensional
manifolds.


title: Wild solutions for 2D incompressible ideal flow with passive tracer

abstract:
  In Ann. Math., 170 (2009), 1417-1436, C. De Lellis and L. Sz\'ekelyhidi Jr.
constructed wild solutions of the incompressible Euler equations using a
reformulation of the Euler equations as a differential inclusion together with
convex integration. In this article we adapt their construction to the system
consisting of adding the transport of a passive scalar to the two-dimensional
incompressible Euler equations.


title: Almost-additivity of analytic capacity and Cauchy independent measures

abstract:
  We show that, given a family of discs centered at a chord-arc curve, the
analytic capacity of a union of arbitrary subsets of these discs (one subset in
each disc) is comparable with the sum of their analytic capacities. We show a
sort of converse to this geometric statement as well. However, we need that the
discs in question would be separated, and it is not clear whether the
separation condition is essential or not. We apply this result to find families
$\{\mu_j\}$ of measures in $\mathbb{C}$ with the following property. If the
Cauchy integral operators $\mathcal{C}_{\mu_j}$ from $L^2(\mu_j)$ to itself are
bounded uniformly in $j$, then $\mathcal{C}_\mu$, $\mu=\sum\mu_j$, is also
bounded from $L^2(\mu)$ to itself.


title:
Mass Accretion Processes in Young Stellar Objects: Role of Intense
  Flaring Activity

abstract:
  According to the magnetospheric accretion scenario, young low-mass stars are
surrounded by circumstellar disks which they interact with through accretion of
mass. The accretion builds up the star to its final mass and is also believed
to power the mass outflows, which may in turn have a significant role in
removing the excess angular momentum from the star-disk system. Although the
process of mass accretion is a critical aspect of star formation, some of its
mechanisms are still to be fully understood. On the other hand, strong flaring
activity is a common feature of young stellar objects (YSOs). In the Sun, such
events give rise to perturbations of the interplanetary medium. Similar but
more energetic phenomena occur in YSOs and may influence the circumstellar
environment. In fact, a recent study has shown that an intense flaring activity
close to the disk may strongly perturb the stability of circumstellar disks,
thus inducing mass accretion episodes (Orlando et al. 2011). Here we review the
main results obtained in the field and the future perspectives.


title: Inhomogeneous Long-Range Percolation for Real-Life Network Modeling

abstract:
  The study of random graphs has become very popular for real-life network
modeling such as social networks or financial networks. Inhomogeneous
long-range percolation (or scale-free percolation) on the lattice $\mathbb
Z^d$, $d\ge1$, is a particular attractive example of a random graph model
because it fulfills several stylized facts of real-life networks. For this
model various geometric properties such as the percolation behavior, the degree
distribution and graph distances have been analyzed. In the present paper we
complement the picture about graph distances. Moreover, we prove continuity of
the percolation probability in the phase transition point.


title: Effective Hamiltonians for fastly driven tight-binding chains

abstract:
  We consider a single particle tunnelling in a tight-binding model with
nearest-neighbour couplings, in the presence of a periodic high-frequency
force. An effective Hamiltonian for the particle is derived using an averaging
method resembling classical canonical perturbation theory. Three cases are
considered: uniform lattice with periodic and open boundary conditions, and
lattice with a parabolic potential. We find that in the latter case, interplay
of the potential and driving leads to appearence of the effective next-nearest
neighbour couplings. In the uniform case with periodic boundary conditions the
second- and third-order corrections to the averaged Hamiltonian are completely
absent, while in the case with open boundary conditions they have a very simple
form, found before in some particular cases by S.Longhi [Phys. Rev. B 77,
195326 (2008)]. These general results may found applications in designing
effective Hamiltonian models in experiments with ultracold atoms in optical
lattices, e.g. for simulating solid-state phenomena.


title: A gravity term from spontaneous symmetry breaking

abstract:
  In this model, the gravity term in the Lagrangean comes from spontaneous
symmetry breaking of an additional scalar quadruplet field $\Upsilon$. The
resulting gravitational field is approximate to one of the models of coframe
gravity with parameters $\rho_1 + 4 \rho_2 = 0$, $\rho_3 = 0$. This article
includes an exact solution of coframe gravity with model parameters $\rho_1
\neq 0$, $\rho_2$ any, $\rho_3 = 0$, which is Newtonian at infinity. An
iteration process is given to construct a solution for a given matter-radiation
stress-energy tensor.


title: Traffic congestion in interconnected complex networks

abstract:
  Traffic congestion in isolated complex networks has been investigated
extensively over the last decade. Coupled network models have recently been
developed to facilitate further understanding of real complex systems. Analysis
of traffic congestion in coupled complex networks, however, is still relatively
unexplored. In this paper, we try to explore the effect of interconnections on
traffic congestion in interconnected BA scale-free networks. We find that
assortative coupling can alleviate traffic congestion more readily than
disassortative and random coupling when the node processing capacity is
allocated based on node usage probability. Furthermore, the optimal coupling
probability can be found for assortative coupling. However, three types of
coupling preferences achieve similar traffic performance if all nodes share the
same processing capacity. We analyze interconnected Internet AS-level graphs of
South Korea and Japan and obtain similar results. Some practical suggestions
are presented to optimize such real-world interconnected networks accordingly.


title: Spatial patterns of competing random walkers

abstract:
  We review recent results obtained from simple individual-based models of
biological competition in which birth and death rates of an organism depend on
the presence of other competing organisms close to it. In addition the
individuals perform random walks of different types (Gaussian diffusion and
L\'{e}vy flights). We focus on how competition and random motions affect each
other, from which spatial instabilities and extinctions arise. Under suitable
conditions, competitive interactions lead to clustering of individuals and
periodic pattern formation. Random motion has a homogenizing effect and then
delays this clustering instability. When individuals from species differing in
their random walk characteristics are allowed to compete together, the ones
with a tendency to form narrower clusters get a competitive advantage over the
others. Mean-field deterministic equations are analyzed and compared with the
outcome of the individual-based simulations.


title: Explicit solutions of PDE via Vessiot theory and solvable structures

abstract:
  We consider the problem of computing the integrable sub-distributions of the
non-integrable Vessiot distribution of multi-dimensional second order partial
differential equations (PDEs). We use Vessiot theory and solvable structures to
find the largest integrable distributions contained in the Vessiot distribution
associated to second order PDEs. In particular, we show how the solvable
symmetry structure of the original PDE can be used to construct integrable
sub-distributions leading to group invariant solutions of the PDE in two and
more than two independent variables.


title: Topological Spin Texture in a Quantum Anomalous Hall Insulator

abstract:
  The quantum anomalous Hall (QAH) effect has been recently discovered in
experiment using thin-film topological insulator with ferromagnetic ordering
and strong spin-orbit coupling. Here we investigate the spin degree of freedom
of a QAH insulator and uncover a fundamental phenomenon that the edge states
exhibit topologically stable spin texture in the boundary when a chiral-like
symmetry is present. This result shows that edge states are chiral in both the
orbital and spin degrees of freedom, and the chiral edge spin texture
corresponds to the bulk topological states of the QAH insulator. We also study
the potential applications of the edge spin texture in designing
topological-state-based spin devices which might be applicable to future
spintronic technologies.


title: Deposition of thin silicon layers on transferred large area CVD graphene

abstract:
  Physical vapor deposition of Si onto transferred graphene is investigated. At
elevated temperatures, Si nucleates preferably on wrinkles and multilayer
graphene islands. In some cases, however, Si can be quasi-selectively grown
only on the monolayer graphene regions while the multilayer islands remain
uncovered. Experimental insights and ab initio calculations show that
variations in the removal efficiency of carbon residuals after the transfer
process can be responsible for this behavior. Low-temperature Si seed layer
results in improved wetting and enables homogeneous growth. This is an
important step towards realization of electronic devices in which graphene is
embedded between two Si layers.


title: Faster SVD-Truncated Least-Squares Regression

abstract:
  We develop a fast algorithm for computing the "SVD-truncated" regularized
solution to the least-squares problem: $ \min_{\x} \TNorm{\matA \x - \b}. $ Let
$\matA_k$ of rank $k$ be the best rank $k$ matrix computed via the SVD of
$\matA$. Then, the SVD-truncated regularized solution is: $ \x_k =
\pinv{\matA}_k \b. $ If $\matA$ is $m \times n$, then, it takes $O(m n
\min\{m,n\})$ time to compute $\x_k $ using the SVD of \math{\matA}. We give an
approximation algorithm for \math{\x_k} which constructs a rank-\math{k}
approximation $\tilde{\matA}_{k}$ and computes $ \tilde{\x}_{k} =
\pinv{\tilde\matA}_{k} \b$ in roughly $O(\nnz(\matA) k \log n)$ time. Our
algorithm uses a randomized variant of the subspace iteration. We show that,
with high probability: $ \TNorm{\matA \tilde{\x}_{k} - \b} \approx \TNorm{\matA
\x_k - \b}$ and $\TNorm{\x_k - \tilde\x_k} \approx 0. $


title:
Mean Value Theorems for L-functions over Prime Polynomials for the
  Rational Function Field

abstract:
  The first and second moments are established for the family of quadratic
Dirichlet $L$--functions over the rational function field at the central point
$s=\tfrac{1}{2}$ where the character $\chi$ is defined by the Legendre symbol
for polynomials over finite fields and runs over all monic irreducible
polynomials $P$ of a given odd degree. Asymptotic formulae are derived for
fixed finite fields when the degree of $P$ is large. The first moment obtained
here is the function field analogue of a result due to Jutila in the
number--field setting. The approach is based on classical analytical methods
and relies on the use of the analogue of the approximate functional equation
for these $L$--functions.


title: A possible definition of a {\it Realistic} Physics Theory

abstract:
  A definition of a {\it Realistic} Physics Theory is proposed based on the
idea that, at all time, the set of physical properties possessed (at that time)
by a system should unequivocally determine the probabilities of outcomes of all
possible measurements.


title: The extremely red L dwarf ULAS J222711$-$004547 - dominated by dust

abstract:
  We report the discovery of a peculiar L dwarf from the UKIDSS LAS, ULAS
J222711-004547. The very red infrared photometry (MKO J-K = 2.79$\pm$0.06, WISE
W1-W2 = 0.65$\pm$0.05) of ULAS J222711-004547 makes it one of the reddest brown
dwarfs discovered so far. We obtained a moderate resolution spectrum of this
target, and classify it as L7pec, confirming its very red nature. Comparison to
theoretical models suggests that the object could be a low-gravity L dwarf with
a solar or higher than solar metallicity. Nonetheless, the match of such fits
to the spectrum is rather poor and this and other peculiar red L dwarfs pose
new challenges for the modeling of ultracool atmospheres. We determined the
proper motion of ULAS J222711-004547 using the data available in the
literature, and we find that its kinematics do not suggest membership of any of
the known young associations. We show that applying a simple de-reddening curve
to its spectrum allows it to resemble the spectra of the L7 spectroscopic
standards. Given the negligible interstellar reddening of the field containing
our target, we conclude that the reddening of the spectrum is mostly due to an
excess of dust in the photosphere of the target. De-reddening the spectrum
using extinction curves for different dust species gives surprisingly good
results and suggests a characteristic grain size of $\sim$0.5 $\mu$m. We show
that by increasing the optical depth, the same extinction curves allow the
spectrum of ULAS J222711-004547 to resemble the spectra of unusually blue L
dwarfs and slightly metal-poor L dwarfs. Grains of similar size yield very good
fits when de-reddening other unusually red L dwarfs in the L5 to L7.5 range.
These results suggest that the diversity in near infrared colours and spectra
seen in late-L dwarfs could be due to differences in the optical thickness of
the dust cloud deck.


title: The Carbon Inventory in a Quiescent, Filamentary Molecular Cloud in G328

abstract:
  We present spectral line images of [CI] 809 GHz, CO J=1-0 115 GHz and HI 1.4
GHz line emission, and calculate the corresponding C, CO and H column
densities, for a sinuous, quiescent Giant Molecular Cloud about 5 kpc distant
along the l=328{\deg} sightline (hereafter G328) in our Galaxy. The [CI] data
comes from the High Elevation Antarctic Terahertz (HEAT) telescope, a new
facility on the summit of the Antarctic plateau where the precipitable water
vapor falls to the lowest values found on the surface of the Earth. The CO and
HI datasets come from the Mopra and Parkes/ATCA telescopes, respectively. We
identify a filamentary molecular cloud, ~75 x 5 pc long with mass ~4 x 10E4
Msun and a narrow velocity emission range of just 4 km/s. The morphology and
kinematics of this filament are similar in CO, [CI] and HI, though in the
latter appears as self-absorption. We calculate line fluxes and column
densities for the three emitting species, which are broadly consistent with a
PDR model for a GMC exposed to the average interstellar radiation field. The
[C/CO] abundance ratio averaged through the filament is found to be
approximately unity. The G328 filament is constrained to be cold (Tdust < 20K)
by the lack of far-IR emission, to show no clear signs of star formation, and
to only be mildly turbulent from the narrow line width. We suggest that it may
represent a GMC shortly after formation, or perhaps still be in the process of
formation.


title: Three-arc graphs: characterization and domination

abstract:
  An arc of a graph is an oriented edge and a 3-arc is a 4-tuple $(v,u,x,y)$ of
vertices such that both $(v,u,x)$ and $(u,x,y)$ are paths of length two. The
3-arc graph of a graph $G$ is defined to have vertices the arcs of $G$ such
that two arcs $uv, xy$ are adjacent if and only if $(v,u,x,y)$ is a 3-arc of
$G$. In this paper we give a characterization of 3-arc graphs and obtain sharp
upper bounds on the domination number of the 3-arc graph of a graph $G$ in
terms that of $G$.


title: Sub-20-Attosecond Timing Jitter Mode-Locked Fiber Lasers

abstract:
  We demonstrate 14.3-attosecond timing jitter [integrated from 10 kHz to 94
MHz offset frequency] optical pulse trains from 188-MHz repetition-rate
mode-locked Yb-fiber lasers. In order to minimize the timing jitter, we shorten
the non-gain fiber length to shorten the pulsewidth and reduce excessive
higher-order nonlinearity and nonlinear chirp in the fiber laser. The measured
jitter spectrum is limited by the amplified spontaneous emission limited
quantum noise in the 100 kHz - 1 MHz offset frequency range, while it was
limited by the relative intensity noise-converted jitter in the lower offset
frequency range. This intrinsically low timing jitter enables
sub-100-attosecond synchronization between the two mode-locked Yb-fiber lasers
over the full Nyquist frequency with a modest 10-kHz locking bandwidth. The
demonstrated performance is the lowest timing jitter measured from any
free-running mode-locked fiber lasers, comparable to the performance of the
lowest-jitter Ti:sapphire solid-state lasers.


title: The robust component structure of dense regular graphs and applications

abstract:
  In this paper, we study the large-scale structure of dense regular graphs.
This involves the notion of robust expansion, a recent concept which has
already been used successfully to settle several longstanding problems. Roughly
speaking, a graph is robustly expanding if it still expands after the deletion
of a small fraction of its vertices and edges. Our main result allows us to
harness the useful consequences of robust expansion even if the graph itself is
not a robust expander. It states that every dense regular graph can be
partitioned into `robust components', each of which is a robust expander or a
bipartite robust expander. We apply our result to obtain (amongst others) the
following. (i) We prove that whenever $\eps >0$, every sufficiently large
3-connected D-regular graph on n vertices with $D \geq (1/4 + \eps)n$ is
Hamiltonian. This asymptotically confirms the only remaining case of a
conjecture raised independently by Bollob\'as and H\"aggkvist in the 1970s.
(ii) We prove an asymptotically best possible result on the circumference of
dense regular graphs of given connectivity. The 2-connected case of this was
conjectured by Bondy and proved by Wei.


title: The dynamics of semigroups of transcendental entire functions II

abstract:
  We introduce the concept of escaping set for semigroups of transcendental
entire functions using Fatou-Julia theory. Several results of the escaping set
associated with the iteration of one transcendental entire function have been
extended to transcendental semigroups. We also investigate the properties of
escaping sets for conjugate semigroups and abelian transcendental semigroups.
Several classes of transcendental semigroups for which Eremenko's conjectures
hold have been provided.


abstract:
  In this paper we study Cartan subalgebras in general and special linear
algebras over a field of positive characteristic. We determined the conjugacy
classes of Cartan subalgebras under the general linear groups, and count the
explicit number of all Cartan subalgebras from its conjugacy when the base
field is an arbitrary finite field.


title:
Simulation of strong nonlinear waves with vectorial lattice Boltzmann
  schemes

abstract:
  We show that an hyperbolic system with a mathematical entropy can be
discretized with vectorial lattice Boltzmann schemes with the methodology of
kinetic representation of the dual entropy. We test this approach for the
shallow water equations in one and two space dimensions. We obtain interesting
results for a shock tube, reflection of a shock wave and unstationary
two-dimensional propagation. This contribution shows the ability of vectorial
lattice Boltzmann schemes to simulate strong nonlinear waves in unstationary
situations.


title: Sup*inf inequalities for scalar curvature equation in dimension 4 and 5

abstract:
  We give some estimates of type sup*inf for the prescribed scalar curvature
equation in dimension 4 and 5, under some condtion on the prescribed curvature.


title: The number of ends of critical branching random walks

abstract:
  We investigate the number of topological ends of the trace of branching
random walk (BRW) on a graph, giving a sufficient condition for the trace to
have infinitely many ends. We then describe some interesting examples of
non-symmetric BRWs with just one end.


title: Schur Complement Based Analysis of MIMO Zero-Forcing for Rician Fading

abstract:
  For multiple-input/multiple-output (MIMO) spatial multiplexing with
zero-forcing detection (ZF), signal-to-noise ratio (SNR) analysis for Rician
fading involves the cumbersome noncentral-Wishart distribution (NCWD) of the
transmit sample-correlation (Gramian) matrix. An \textsl{approximation} with a
\textsl{virtual} CWD previously yielded for the ZF SNR an approximate (virtual)
Gamma distribution. However, analytical conditions qualifying the accuracy of
the SNR-distribution approximation were unknown. Therefore, we have been
attempting to exactly characterize ZF SNR for Rician fading. Our previous
attempts succeeded only for the sole Rician-fading stream under
Rician--Rayleigh fading, by writing it as scalar Schur complement (SC) in the
Gramian. Herein, we pursue a more general, matrix-SC-based analysis to
characterize SNRs when several streams may undergo Rician fading. On one hand,
for full-Rician fading, the SC distribution is found to be exactly a CWD if and
only if a channel-mean--correlation \textsl{condition} holds. Interestingly,
this CWD then coincides with the \textsl{virtual} CWD ensuing from the
\textsl{approximation}. Thus, under the \textsl{condition}, the actual and
virtual SNR-distributions coincide. On the other hand, for Rician--Rayleigh
fading, the matrix-SC distribution is characterized in terms of determinant of
matrix with elementary-function entries, which also yields a new
characterization of the ZF SNR. Average error probability results validate our
analysis vs.~simulation.


title: A gluing formula for Reidemeister-Turaev torsion

abstract:
  We extend Turaev's theory of Euler structures and torsion invariants on
3-manifolds to the case of vector fields having generic behavior on the
boundary. This allows to easily define gluings of Euler structures and to
develop a completely general gluing formula for Reidemeister torsion of
3-manifolds. Lastly, we describe a combinatorial presentation of Euler
structures via stream-spines, as a tool to effectively compute torsion.


title: On Minimum Average Stretch Spanning Trees in Polygonal 2-trees

abstract:
  A spanning tree of an unweighted graph is a minimum average stretch spanning
tree if it minimizes the ratio of sum of the distances in the tree between the
end vertices of the graph edges and the number of graph edges. We consider the
problem of computing a minimum average stretch spanning tree in polygonal
2-trees, a super class of 2-connected outerplanar graphs. For a polygonal
2-tree on $n$ vertices, we present an algorithm to compute a minimum average
stretch spanning tree in $O(n \log n)$ time. This algorithm also finds a
minimum fundamental cycle basis in polygonal 2-trees.


title: A Memory of Majorana Fermions through Quantum Quench

abstract:
  We study the sudden quench of a one-dimensional p-wave superconductor through
its topological signature in the entanglement spectrum. The long-time evolution
of the system and its topological characterization depend on a pseudomagnetic
field ${\bs R}_{\mbox{\text eff}}(k)$, which connects both the initial and the
final Hamiltonians, hence exhibiting a memory effect. In particular, we explore
the robustness of the Majorana zero-mode associated with the entanglement cut
in the topologically nontrivial phase and identify the parameter space in which
the mode can survive in the infinite-time limit.


title: Flat minimal quantizations of Stackel systems and quantum separability

abstract:
  In this paper, we consider the problem of quantization of classical St\"ackel
systems and the problem of separability of related quantum Hamiltonians. First,
using the concept of St\"ackel transform, all considered systems are expressed
by flat coordinates of related Euclidean configuration space. Then, the
so-called flat minimal quantization procedure is applied in order to construct
an appropriate Hermitian operator in the respective Hilbert space. Finally, we
distinguish a class of St\"ackel systems which remains separable after any of
admissible flat minimal quantizations.


title:
A global minimization algorithm for Tikhonov functionals with sparsity
  constraints

abstract:
  In this paper we present a globally convergent algorithm for the computation
of a minimizer of the Tikhonov functional with sparsity promoting penalty term
for nonlinear forward operators in Banach space. The dual TIGRA method uses a
gradient descent iteration in the dual space at decreasing values of the
regularization parameter $\alpha_j$, where the approximation obtained with
$\alpha_j$ serves as the starting value for the dual iteration with parameter
$\alpha_{j+1}$. With the discrepancy principle as a global stopping rule the
method further yields an automatic parameter choice. We prove convergence of
the algorithm under suitable step-size selection and stopping rules and
illustrate our theoretic results with numerical experiments for the nonlinear
autoconvolution problem.


title:
Optical interference in view of the probability distribution of photon
  detection

abstract:
  We investigate interference of optical fields by examining the probability
distribution of photon detection. The usual description of interference
patterns in terms of superposition of classical mean fields with definite
phases is elucidated in quantum fashion. Especially, for interference of two
independent mixtures of number states with Poissonian or sub-Poissonian
statistics, despite lack of intrinsic phases, it is found that the joint
probability has a distinct peak manifold in the multi-dimensional space of the
detector outcomes, which is along the trajectory of the mean-field values as
the relative phase varies on the unit circle. Then, an interference pattern
should mostly appear in each shot of measurement as a point in the peak
manifold with a randomly chosen relative phase. On the other hand, for
super-Poissonian sources the mean-field description is likely invalidated with
rather broad probability distributions.


title:
UROP: A Simple, Near-Optimal Scheduling Policy for Energy Harvesting
  Sensors

abstract:
  This paper considers a single-hop wireless network where a central node (or
fusion center, FC) collects data from a set of m energy harvesting (EH) nodes
(e.g. nodes of a wireless sensor network). In each time slot, k of m nodes can
be scheduled by the FC for transmission over k orthogonal channels. FC has no
knowledge about EH processes and current battery states of nodes; however, it
knows outcomes of previous transmission attempts. The objective is to find a
low complexity scheduling policy that maximizes total throughput of the data
backlogged system using the harvested energy, for all types (uniform,
non-uniform, independent, correlated (i.e. Markovian), etc.) EH processes.
Energy is assumed to be stored losslessly in the nodes batteries, up to a
storage capacity (the infinite capacity case is also considered.) The problem
is treated in finite and infinite problem horizons. A low-complexity policy,
UROP (Uniformizing Random Ordered Policy) is proposed, whose near optimality is
shown. Numerical examples indicate that under a reasonable-sized battery
capacity, UROP uses the arriving energy with almost perfect efficiency. As the
problem is a restless multi-armed bandit (RMAB) problem with an average reward
criterion, UROP may have a wider application area than communication networks.


title:
Flavor dependence of chiral odd generalized parton distributions and the
  tensor charge from the analysis of combined $\pi^0$ and $\eta$ exclusive
  electroproduction data

abstract:
  Using a physically motivated parameterization based on the reggeized diquark
model we perform a flavor separation of the chiral-odd generalized parton
distributions obtained from both $\pi^0$ and $\eta$ exclusive
electroproduction. In our approach we exploit a connection between the
chiral-even and chiral-odd reduced helicity amplitudes using Parity
transformations that are relevant for a class of models that includes
two-component models. We compare our results for $\eta$ production to the
previously obtained $\pi^0$ results, and we make predictions for the transverse
single spin asymmetry components which will be measured within the Jefferson
Lab 12 GeV program.


title:
Single- and coupled-channel radial inverse scattering with
  supersymmetric transformations

abstract:
  The present status of the coupled-channel inverse-scattering method with
supersymmetric transformations is reviewed. We first revisit in a pedagogical
way the single-channel case, where the supersymmetric approach is shown to
provide a complete solution to the inverse-scattering problem. A special
emphasis is put on the differences between conservative and non-conservative
transformations. In particular, we show that for the zero initial potential, a
non-conservative transformation is always equivalent to a pair of conservative
transformations. These single-channel results are illustrated on the inversion
of the neutron-proton triplet eigenphase shifts for the S and D waves. We then
summarize and extend our previous works on the coupled-channel case and stress
remaining difficulties and open questions. We mostly concentrate on two-channel
examples to illustrate general principles while keeping mathematics as simple
as possible. In particular, we discuss the difference between the
equal-threshold and different-threshold problems. For equal thresholds,
conservative transformations can provide non-diagonal Jost and scattering
matrices. Iterations of such transformations are shown to lead to practical
algorithms for inversion. A convenient technique where the mixing parameter is
fitted independently of the eigenphases is developed with iterations of pairs
of conjugate transformations and applied to the neutron-proton triplet S-D
scattering matrix, for which exactly-solvable matrix potential models are
constructed. For different thresholds, conservative transformations do not seem
to be able to provide a non-trivial coupling between channels. In contrast, a
single non-conservative transformation can generate coupled-channel potentials
starting from the zero potential and is a promising first step towards a full
solution to the coupled-channel inverse problem with threshold differences.


title:
Surface roughness evolution in a solid-on-solid model of epitaxial
  growth

abstract:
  The paper presents results from kinetic Monte Carlo simulations of kinetic
surface roughening using an important and experimentally relevant model of
epitaxial growth -- the solid-on-solid model with Arrhenius dynamics. A
restriction on diffusing adatoms is included allowing hopping down only at
steps of height one monolayer in order to avoid possibly unrealistic events of
jumping from arbitrarily high steps. Simulation results and precise analytic
expressions representing the time evolution of surface roughness do not depend
on the substrate size and clearly put forward the conclusion that for any basic
set of parameters the model approaches in asymptotic limit the usual random
deposition process with growth exponent $\beta=1/2$. At high temperatures, it
is preceded by a long transient regime characterized by a smooth surface
covered with porous pillars and described by a power law with $\beta=3/4$.


title:
A Fibering Map Approach for a Laplacian System With Sign-Changing Weight
  Function

abstract:
  We prove the existence of at least two positive solutions for the Laplacian
system(E?)On a bounded region by using the Nehari manifold and the fibering
maps associated with the Euler functional for the system.


title:
Elementary approach to closed billiard trajectories in asymmetric normed
  spaces

abstract:
  We apply the technique of K\'aroly Bezdek and Daniel Bezdek to study billiard
trajectories in convex bodies, when the length is measured with a (possibly
asymmetric) norm. We prove a lower bound for the length of the shortest closed
billiard trajectory, related to the non-symmetric Mahler problem. With this
technique we are able to give short and elementary proofs to some known
results.


title: Selection Lemmas for various geometric objects

abstract:
  Selection lemmas are classical results in discrete geometry that have been
well studied and have applications in many geometric problems like weak epsilon
nets and slimming Delaunay triangulations. Selection lemma type results
typically show that there exists a point that is contained in many objects that
are induced (spanned) by an underlying point set.
  In the first selection lemma, we consider the set of all the objects induced
(spanned) by a point set $P$. This question has been widely explored for
simplices in $\mathbb{R}^d$, with tight bounds in $\mathbb{R}^2$. In our paper,
we prove first selection lemma for other classes of geometric objects. We also
consider the strong variant of this problem where we add the constraint that
the piercing point comes from $P$. We prove an exact result on the strong and
the weak variant of the first selection lemma for axis-parallel rectangles,
special subclasses of axis-parallel rectangles like quadrants and slabs, disks
(for centrally symmetric point sets). We also show non-trivial bounds on the
first selection lemma for axis-parallel boxes and hyperspheres in
$\mathbb{R}^d$.
  In the second selection lemma, we consider an arbitrary $m$ sized subset of
the set of all objects induced by $P$. We study this problem for axis-parallel
rectangles and show that there exists an point in the plane that is contained
in $\frac{m^3}{24n^4}$ rectangles. This is an improvement over the previous
bound by Smorodinsky and Sharir when $m$ is almost quadratic.