title: Long-Duration Gamma-Ray Burst Host Galaxies in Emission and Absorption

abstract:
  The galaxy population hosting long-duration GRBs provides a means to
constrain the progenitor and an opportunity to use these violent explosions to
characterize the nature of the high-redshift universe. Studies of GRB host
galaxies in emission reveal a population of star-forming galaxies with great
diversity, spanning a wide range of masses, metallicities, and redshifts.
However, as a population GRB hosts are significantly less massive and poorer in
metals than the hosts of other core-collapse transients, suggesting that GRB
production is only efficient at metallicities significantly below Solar. GRBs
may also prefer compact galaxies, and dense and/or central regions of galaxies,
more than other types of core-collapse explosion. Meanwhile, studies of hosts
in absorption against the luminous GRB optical afterglow provide a unique means
of unveiling properties of the ISM in even the faintest and most distant
galaxies; these observations are helping to constrain the chemical evolution of
galaxies and the properties of interstellar dust out to very high redshifts.
New ground- and space-based instrumentation, and the accumulation of larger and
more carefully-selected samples, are continually enhancing our view of the GRB
host population.


title: Distributed Nash Equilibrium Seeking by A Consensus Based Approach

abstract:
  In this paper, Nash equilibrium seeking among a network of players is
considered. Different from many existing works on Nash equilibrium seeking in
non-cooperative games, the players considered in this paper cannot directly
observe the actions of the players who are not their neighbors. Instead, the
players are supposed to be capable of communicating with each other via an
undirected and connected communication graph. By a synthesis of a
leader-following consensus protocol and the gradient play, a distributed Nash
equilibrium seeking strategy is proposed for the non-cooperative games.
Analytical analysis on the convergence of the players' actions to the Nash
equilibrium is conducted via Lyapunov stability analysis. For games with
non-quadratic payoffs, where multiple isolated Nash equilibria may coexist in
the game, a local convergence result is derived under certain conditions. Then,
a stronger condition is provided to derive a non-local convergence result for
the non-quadratic games. For quadratic games, it is shown that the proposed
seeking strategy enables the players' actions to converge to the Nash
equilibrium globally under the given conditions. Numerical examples are
provided to verify the effectiveness of the proposed seeking strategy.


title:
On free-stream preservation in stationary grids for arbitrary linear
  upwind schemes

abstract:
  In order to improve the application maturity of high-order difference
schemes, the free-stream preservation property, whose importance has been
widely recognized in recent years, has been developed into a focus of study..
In past literatures, only central schemes are considered to be suitable for
free-stream preservation. In this study, the methodology for arbitrary linear
schemes to achieve the property is investigated. First, derivations of grid
metric by Thomas, Lombard and Neier are reviewed, through which linear schemes
for the metric and unsplit flux could attain the property by the proof of
Vinokur and Yee firstly. In practical applications, flux splittings are usually
at presence and therefore the direct use of upwind schemes seems difficult to
fulfill free-stream preservation. To overcome the difficulty, two attempts are
made: firstly, a central-scheme-decomposition is worked out, through which a
central difference scheme is derived to approximate the first-order partial
derivative in metric evaluations; secondly, treatments are proposed for flux
splitting and a concrete example is presented. Through these two attempts, the
linear upwind node schemes can achieve the property. For half-node or mixed
type schemes, interpolations should be used to derive variables at half nodes.
As a result, a directionally consistent interpolation is proposed, which is
shown to be necessary in order to avoid violation of the metric identity and
free-stream preservation. Two numerical problems are also tested, i.e., the
free-stream and vortex preservation on wavy, largely randomized and triangular
grids. Numerical results validate aforementioned theoretical outcomes;
especially, simulations on the triangular grids indicate the methods discussed
in this study, which are typical algorithms on structured grids, has the
application potential for problems on unstructured meshes.


title: Querying Evolving Graphs with Portal

abstract:
  Graphs are used to represent a plethora of phenomena, from the Web and social
networks, to biological pathways, to semantic knowledge bases. Arguably the
most interesting and important questions one can ask about graphs have to do
with their evolution. Which Web pages are showing an increasing popularity
trend? How does influence propagate in social networks? How does knowledge
evolve?
  This paper proposes a logical model of an evolving graph called a TGraph,
which captures evolution of graph topology and of its vertex and edge
attributes. We present a compositional temporal graph algebra TGA, and show a
reduction of TGA to temporal relational algebra with graph-specific primitives.
We formally study the properties of TGA, and also show that it is sufficient to
concisely express a wide range of common use cases. We describe an
implementation of our model and algebra in Portal, built on top of Apache Spark
/ GraphX. We conduct extensive experiments on real datasets, and show that
Portal scales.


title: Tautological systems under the conifold transition on $G(2, 4)$

abstract:
  Via a natural degeneration of Grassmannian manifolds $G(k,n)$ to Gorenstein
toric Fano varieties $P(k,n)$ with conifold singularities, we suggest an
approach to study the relation between the tautological system on $G(k,n)$ and
the extended GKZ system on the small resolution $\hat{P}(k,n)$ of $P(k,n)$. We
carry out the simplest case $(k,n)=(2,4)$ to ensure its validity and show that
the extended GKZ system can be regarded as a tautological system on
$\hat{P}(2,4)$.


title: Recent work on chemical distance in critical percolation

abstract:
  In this note, we describe some of the progress recently made on questions
regarding the chemical distance in two-dimensional critical percolation by the
author, J. Hanson, and P. Sosoe [6, 7]. It is expected that the distance
between points in critical percolation clusters scales as $\|\cdot \|^{1+s}$,
where $\|\cdot \|$ is the Euclidean distance and $s>0$. First, we review
previous work of Aizenman-Burchard and Morrow-Zhang, which together establish a
version of $0 < s \leq 1/3$. The main results of our work are in the direction
of proving upper bounds on $s$, answering in [6] a question from '93 of
Kesten-Zhang on the ratio of the length of the shortest crossing of a box to
the length of the lowest crossing of a box. The paper [7] provides a
quantitative version of the result of [6], along with bounds on point-to-point
and point-to-set distances.


title:
Kernel Architecture of the Genetic Circuitry of the Arabidopsis
  Circadian System

abstract:
  A wide range of organisms features molecular machines, circadian clocks,
which generate endogenous oscillations with ~24 h periodicity and thereby
synchronize biological processes to diurnal environmental fluctuations.
Recently, it has become clear that plants harbor more complex gene regulatory
circuits within the core circadian clocks than other organisms, inspiring a
fundamental question: are all these regulatory interactions between clock genes
equally crucial for the establishment and maintenance of circadian rhythms? Our
mechanistic simulation for Arabidopsis thaliana demonstrates that at least half
of the total regulatory interactions must be present to express the circadian
molecular profiles observed in wild-type plants. A set of those essential
interactions is called herein a kernel of the circadian system. The kernel
structure unbiasedly reveals four interlocked negative feedback loops
contributing to circadian rhythms, and three feedback loops among them drive
the autonomous oscillation itself. Strikingly, the kernel structure, as well as
the whole clock circuitry, is overwhelmingly composed of inhibitory, rather
than activating, interactions between genes. We found that this tendency
underlies plant circadian molecular profiles which often exhibit
sharply-shaped, cuspidate waveforms. Through the generation of these cuspidate
profiles, inhibitory interactions may facilitate the global coordination of
temporally-distant clock events that are markedly peaked at very specific times
of day. Our systematic approach resulting in experimentally-testable
predictions provides insights into a design principle of biological clockwork,
with implications for synthetic biology.


title:
Arrested kinetics of the CO-I to FM-M transition and the phase separated
  glassy state in manganites: a Comment on Kundhikanjana et al PRL 115 (2015)
  265701 and Kundhikanjana et al arXiv:1306.3065v1 (2013)

abstract:
  This is a Comment on Kundhikanjana et al PRL 115 (2015) 265701 and the
earlier Kundhikanjana et al arXiv:1306.3065v1 (2013)


title: On a lower bound for sorting signed permutations by reversals

abstract:
  Computing the reversal distances of signed permutations is an important topic
in Bioinformatics. Recently, a new lower bound for the reversal distance was
obtained via the plane permutation framework. This lower bound appears
different from the existing lower bound obtained by Bafna and Pevzner through
breakpoint graphs. In this paper, we prove that the two lower bounds are equal.
Moreover, we confirm a related conjecture on skew-symmetric plane permutations,
which can be restated as follows: let $p=(0,-1,-2,\ldots -n,n,n-1,\ldots 1)$
and let
  $$
  \tilde{s}=(0,a_1,a_2,\ldots a_n,-a_n,-a_{n-1},\ldots -a_1)
  $$ be any long cycle on the set $\{-n,-n+1,\ldots 0,1,\ldots n\}$. Then, $n$
and $a_n$ are always in the same cycle of the product $p\tilde{s}$.
Furthermore, we show the new lower bound via plane permutations can be
interpreted as the topological genera of orientable surfaces associated to
signed permutations.


title:
Kinetic signatures of the region surrounding the X-line in asymmetric
  (magnetopause) reconnection

abstract:
  Kinetic particle-in-cell simulations are used to identify signatures of the
electron diffusion region (EDR) and its surroundings during asymmetric magnetic
reconnection. A "shoulder" in the sunward pointing normal electric field (EN >
0) at the reconnection magnetic field reversal is a good indicator of the EDR,
and is caused by magnetosheath electron meandering orbits in the vicinity of
the x-line. Earthward of the X-line, electrons accelerated by EN form strong
currents and crescent-shaped distribution functions in the plane perpendicular
to B. Just downstream of the X-line, parallel electric fields create
field-aligned crescent electron distribution functions. In the immediate
upstream magnetosheath, magnetic field strength, plasma density, and
perpendicular electron temperatures are lower than the asymptotic state. In the
magnetosphere inflow region, magnetosheath ions intrude resulting in an
Earthward pointing electric field and parallel heating of magnetospheric
particles. Many of the above properties persist with a guide field of at least
unity.


title: Spectral summation formula for GSp(4) and moments of spinor L-functions

abstract:
  We compute the first and second moment of the spinor L-function at the
central point of Siegel modular forms of large weight k with power saving error
term and give applications to non-vanishing.


title:
Robust entanglement between a movable mirror and atomic ensemble and
  entanglement transfer in coupled optomechanical system

abstract:
  We propose a scheme for the creation of robust entanglement between a movable
mirror and atomic ensemble at the macroscopic level in coupled optomechanical
system. In experimentally accessible parameter regimes, we show that critical
temperature of the bipartite continuous variable entanglement in our scheme can
be raised from previous 24 K [Vitali {\it et al.}, Phys. Rev. Lett.
\textbf{98}, 030405 (2007)] and 20 K [Genes {\it et al.}, Phys. Rev. A
\textbf{77}, 050307(R) (2008)] to 32 K. We also investigate the entanglement
transfer based on this coupled system. The scheme can be used for the
realization of quantum memories for continuous variable quantum information
processing and quantum-limited displacement measurements.


title: Portfolio Selection: The Power of Equal Weight

abstract:
  We empirically show the superiority of the equally weighted S\&P 500
portfolio over Sharpe's market capitalization weighted S\&P 500 portfolio. We
proceed to consider the MaxMedian rule, a non-proprietary rule designed for the
investor who wishes to do his/her own investing on a laptop with the purchase
of only 20 stocks. Rather surprisingly, over the 1958-2016 horizon, the
cumulative returns of MaxMedian beat those of the equally weighted S\&P 500
portfolio by a factor of 1.15.


title: Measurement of the Multiple-Muon Charge Ratio in the MINOS Far Detector

abstract:
  The charge ratio, $R_\mu = N_{\mu^+}/N_{\mu^-}$, for cosmogenic multiple-muon
events observed at an under- ground depth of 2070 mwe has been measured using
the magnetized MINOS Far Detector. The multiple-muon events, recorded nearly
continuously from August 2003 until April 2012, comprise two independent data
sets imaged with opposite magnetic field polarities, the comparison of which
allows the systematic uncertainties of the measurement to be minimized. The
multiple-muon charge ratio is determined to be $R_\mu = 1.104 \pm 0.006 {\rm
\,(stat.)} ^{+0.009}_{-0.010} {\rm \,(syst.)} $. This measurement complements
previous determinations of single-muon and multiple-muon charge ratios at
underground sites and serves to constrain models of cosmic ray interactions at
TeV energies.


title: Growth and homogeneity of matchbox manifolds

abstract:
  A matchbox manifold with one-dimensional leaves which has equicontinuous
holonomy dynamics must be a homogeneous space, and so must be homeomorphic to a
classical Vietoris solenoid. In this work, we consider the problem, what can be
said about a matchbox manifold with equicontinuous holonomy dynamics, and all
of whose leaves have at most polynomial growth type? We show that such a space
must have a finite covering for which the global holonomy group of its
foliation is nilpotent. As a consequence, we show that if the growth type of
the leaves is polynomial of degree at most 3, then there exists a finite
covering which is homogeneous. If the growth type of the leaves is polynomial
of degree at least 4, then there are additional obstructions to homogeneity,
which arise from the structure of nilpotent groups.


title:
Spectral narrowing and spin echo for localized carriers with
  heavy-tailed Levy distribution of hopping times

abstract:
  We study analytically the free induction decay and the spin echo decay
originating from the localized carriers moving between the sites which host
random magnetic fields. Due to disorder in the site positions and energies, the
on-site residence times, \tau, are widely spread according to the Levy
distribution. The power-law tail \propto \tau^{-1-\alpha} in the distribution
of waiting times does not affect the conventional spectral narrowing for \alpha
>2, but leads to a dramatic acceleration of the free induction decay in the
domain 2>\alpha >1. The next abrupt acceleration of the decay takes place as
the tail parameter, \alpha, becomes smaller than 1. In the latter domain the
decay does not follow a simple-exponent law. To capture the behavior of the
average spin in this domain, we solve the evolution equation for the average
spin using the approach different from the conventional approach based on the
Laplace transform. Unlike the free induction decay, the tail in the
distribution of the residence times leads to the slow decay of the spin echo.
The echo is dominated by realizations of the carrier motion for which the
number of sites, visited by the carrier, is minimal.


title: Proceedings Fourth Workshop on Synthesis

abstract:
  The SYNT workshop aims to bring together researchers interested in the broad
area of synthesis of computing systems. The goal is to foster the development
of frontier techniques in automating the development of computing system.
Contributions of interest include algorithms, complexity and decidability
analysis, as well as reproducible heuristics, implemented tools, and
experimental evaluation. Application domains include software, hardware,
embedded, and cyberphysical systems. Computation models include functional,
reactive, hybrid and timed systems. Identifying, formalizing, and evaluating
synthesis in particular application domains is encouraged.
  The fourth iteration of the workshop took place in San Francisco, CA, USA. It
was co-located with the 27th International Conference on Computer Aided
Verification. The workshop included five contributed talks and two invited
talks. In addition, it featured a special session about the Syntax-Guided
Synthesis Competition (SyGuS) and the SyntComp Synthesis competition.


title:
Forward Modelling of Propagating Slow Waves in Coronal Loops and Their
  Frequency-Dependent Damping

abstract:
  Propagating slow waves in coronal loops exhibit a damping which depends upon
the frequency of the waves. In this study we aim to investigate the
relationship of the damping length (L$_d$) with the frequency of the
propagating wave. We present a 3-D coronal loop model with uniform density and
temperature and investigate the frequency dependent damping mechanism for the
four chosen wave periods. We include the thermal conduction to damp the waves
as they propagate through the loop. The numerical model output has been forward
modelled to generate synthetic images of SDO/AIA 171 \r{A} and 193 \r{A}
channels. The use of forward modelling, which incorporates the atomic emission
properties into the intensity images, allows us to directly compare our results
with the real observations. The results show that the damping lengths vary
linearly with the periods. We also measure the contributions of the emission
properties on the damping lengths by using density values from the simulation.
In addition to that} we have also calculated the theoretical dependence of
L$_d$ with wave periods and showed that it is consistent with the results we
obtained from the numerical modelling and earlier observations.


title: Matrix Factorizations for Local F-Theory Models

abstract:
  I use matrix factorizations to describe branes at simple singularities as
they appear in elliptic fibrations of local F-theory models. Each node of the
corresponding Dynkin diagrams of the ADE-type singularities is associated with
one indecomposable matrix factorization which can be deformed into one or more
factorizations of lower rank. Branes with internal fluxes arise naturally as
bound states of the indecomposable factorizations. Describing branes in such a
way avoids the need to resolve singularities and encodes information which is
neglected in conventional F-theory treatments. This paper aims to show how
branes arising in local F-theory models around simple singularities can be
described in this framework.


title:
Strichartz estimates for the magnetic Schr\"odinger equation with
  potentials $V$ of critical decay

abstract:
  We study the Strichartz estimates for the magnetic Schr\"odinger equation in
dimension $n\geq3$. More specifically, for all Schr\"odinger admissible pairs
$(r,q)$, we establish the estimate
  $$
  \|e^{itH}f\|_{L^{q}_{t}(\mathbb{R}; L^{r}_{x}(\mathbb{R}^n))} \leq
C_{n,r,q,H} \|f\|_{L^2(\mathbb{R}^n)}
  $$ when the operator $H= -\Delta_A +V$ satisfies suitable conditions. In the
purely electric case $A\equiv0$, we extend the class of potentials $V$ to the
Fefferman-Phong class. In doing so, we apply a weighted estimate for the
Schr\"odinger equation developed by Ruiz and Vega. Moreover, for the endpoint
estimate of the magnetic case in $\mathbb{R}^3$, we investigate an equivalence
  $$
  \| H^{\frac{1}{4}} f \|_{L^r(\mathbb{R}^3)} \approx C_{H,r} \big\|
(-\Delta)^{\frac{1}{4}} f \big\|_{L^r(\mathbb{R}^3)}
  $$ and find sufficient conditions on $H$ and $r$ for which the equivalence
holds.


title:
The weakening of fermionization of one dimensional spinor Bose gases
  induced by spin-exchange interaction

abstract:
  We investigate the ground state density distributions of anti-ferromagnetic
spin-1 Bose gases in one dimensional harmonic potential in the full interacting
regimes. The ground state is obtained by diagonalizing the Hamiltonian in the
Hilbert space composed of the lowest eigenstates of noninteracting Bose gas and
spin components. The study reveals that in the situation of weak spin-dependent
interaction the total density profiles evolve from Gaussian-like distribution
to a Fermi-like shell structure of $N$ peaks with the increasing of
spin-independent interaction. While the increasing spin-exchange interaction
always weaken the fermionization of density distribution such that the total
density profiles show shell structure of less peaks and even show single peak
structure in the limit of strong spin-exchange interaction. The weakening of
fermionization results from the formation of composite atoms induced by
spin-exchange interaction. It is also shown that phase separation occurs for
the spinor Bose gas with weak spin-exchange interaction, meanwhile strong
spin-independent interaction.


title:
Analysis and improvement of Tian-Zhang-Li voting protocol based on
  controlled quantum teleportation

abstract:
  Recently Tian, Zhang and Li (TZL) have proposed a protocol for voting based
on controlled quantum teleportation (Int. J. Theor. Phys. DOI
10.1007/s10773-015-2868-8). We have critically analyzed the protocol and have
shown that it's neither efficient nor secure. Further, it is shown that in the
TZL protocol, the scrutineer Charlie does not have the required control over
the voting process. Apart from showing the limitations of TZL protocol, two
improved protocols for quantum voting along the line of TZL protocol are
proposed here. One of the proposed protocols is designed using a standard
scheme of controlled deterministic secure quantum communication, and the other
one is designed using the idea of quantum cryptographic switch which uses a
technique known as permutation of particles (PoP). A few possible alternative
approaches to accomplish the same task have also been discussed. Further, the
efficiencies of the proposed protocols are reported, and it is shown that the
proposed protocols are free from the limitations of the TZL protocol, and they
are more efficient than the TZL protocol.


title: Nuclear forensics using gamma-ray spectroscopy

abstract:
  Much of George Dracoulis's research career was devoted to utilizing gamma-ray
spectroscopy in fundamental studies in nuclear physics. This same technology is
useful in a wide range of applications in the area of nuclear forensics. Over
the past several years, our research group has made use of both high- and low-
resolution gamma ray spectrometers to: identify the first sample of plutonium
large enough to be weighed; determine the yield of the Trinity nuclear
explosion; measure fission fragment yields as a function of target nucleus and
neutron energy; and observe fallout in the U. S. from the Fukushima nuclear
reactor accident.


title:
Construction of interlaced polynomial lattice rules for infinitely
  differentiable functions

abstract:
  We study multivariate integration over the $s$-dimensional unit cube in a
weighted space of infinitely differentiable functions. It is known from a
recent result by Suzuki that there exists a good quasi-Monte Carlo (QMC) rule
which achieves a super-polynomial convergence of the worst-case error in this
function space, and moreover, that this convergence behavior is independent of
the dimension under a certain condition on the weights.
  In this paper we provide a constructive approach to finding a good QMC rule
achieving such a dimension-independent super-polynomial convergence of the
worst-case error. Specifically, we prove that interlaced polynomial lattice
rules, with an interlacing factor chosen properly depending on the number of
points $N$ and the weights, can be constructed using a fast
component-by-component algorithm in at most $O(sN(\log N)^2)$ arithmetic
operations to achieve a dimension-independent super-polynomial convergence. The
key idea for the proof of the worst-case error bound is to use a variant of
Jensen's inequality with a purposely-designed concave function.


title: Causal hydrodynamic fluctuation in Bjorken expansion

abstract:
  We investigate effects of causal hydrodynamic fluctuations in the
longitudinally expanding quark gluon plasma on final entropy distributions in
high-energy nuclear collisions.


title:
Gender, Productivity, and Prestige in Computer Science Faculty Hiring
  Networks

abstract:
  Women are dramatically underrepresented in computer science at all levels in
academia and account for just 15% of tenure-track faculty. Understanding the
causes of this gender imbalance would inform both policies intended to rectify
it and employment decisions by departments and individuals. Progress in this
direction, however, is complicated by the complexity and decentralized nature
of faculty hiring and the non-independence of hires. Using comprehensive data
on both hiring outcomes and scholarly productivity for 2659 tenure-track
faculty across 205 Ph.D.-granting departments in North America, we investigate
the multi-dimensional nature of gender inequality in computer science faculty
hiring through a network model of the hiring process. Overall, we find that
hiring outcomes are most directly affected by (i) the relative prestige between
hiring and placing institutions and (ii) the scholarly productivity of the
candidates. After including these, and other features, the addition of gender
did not significantly reduce modeling error. However, gender differences do
exist, e.g., in scholarly productivity, postdoctoral training rates, and in
career movements up the rankings of universities, suggesting that the effects
of gender are indirectly incorporated into hiring decisions through gender's
covariates. Furthermore, we find evidence that more highly ranked departments
recruit female faculty at higher than expected rates, which appears to inhibit
similar efforts by lower ranked departments. These findings illustrate the
subtle nature of gender inequality in faculty hiring networks and provide new
insights to the underrepresentation of women in computer science.


title:
S-parameter and vector decay constant in QCD with eight fundamental
  fermions

abstract:
  SU(3) gauge theory with eight massless fundamental fermions seems to be near
the conformal boundary, and is a candidate theory of walking technicolor. Along
the series of study by LatKMI collaboration using HISQ fermions, S-parameter
and vector decay constant, which provide important constraints in the model of
electroweak symmetry breaking, are calculated for this theory. Use of various
volumes allows a systematic investigation of finite volume effects. A strong
sensitivity of the S-parameter to the volume is found.


title: Phase constants in the Fock-Goncharov quantum cluster varieties

abstract:
  A cluster variety of Fock and Goncharov is a scheme constructed by gluing
split algebraic tori, called seed tori, via birational gluing maps called
mutations. In quantum theory, the ring of functions on seed tori are deformed
to non-commutative rings, represented as operators on Hilbert spaces. Mutations
are quantized to unitary maps between the Hilbert spaces intertwining the
representations. These unitary intertwiners are described using the quantum
dilogarithm function $\Phi^\hbar$. Algebraic relations among classical
mutations are satisfied by the intertwiners up to complex constants. The
present paper shows that these constants are $1$. So the mapping class group
representations resulting from the Chekhov-Fock-Goncharov quantum Teichm\"uller
theory are genuine, not projective. During the course, the hexagon and the
octagon operator identities for $\Phi^\hbar$ are derived.


title: A Unified Framework for Information Consumption Based on Markov Chains

abstract:
  This paper establishes a Markov chain model as a unified framework for
understanding information consumption processes in complex networks, with clear
implications to the Internet and big-data technologies. In particular, the
proposed model is the first one to address the formation mechanism of the
"trichotomy" in observed probability density functions from empirical data of
various social and technical networks. Both simulation and experimental results
demonstrate a good match of the proposed model with real datasets, showing its
superiority over the classical power-law models.


title:
Effect of the change in the interface structure of Pd(100)/SrTiO3 for
  quantum-well induced ferromagnetism

abstract:
  Pd(100) ultrathin films show ferromagnetism induced by the confinement of
electrons in the film, i.e., the quantum-well mechanism. In this study, we
investigate the effect of the change in the interface structure between a Pd
film and SrTiO3 substrate on quantum-well induced ferromagnetism using the
structural phase transition of SrTiO3. During repeated measurement of
temperature- dependent magnetization of the Pd/SrTiO3 system, cracks were
induced in the Pd overlayer near the interface region by the structural phase
transition of SrTiO3, thereby changing the film-thickness dependence of the
magnetic moment. This is explained by the concept that as the magnetic moment
in Pd(100) changed, so too did the thickness of the quantum-well. In addition,
we observed that the ferromagnetism in the Pd(100) disappeared with the
accumulation of cracks due to the repetition of the temperature cycle through
the phase-transition temperature. This suggests that lowering the crystallinity
of the interface structure by producing a large number of cracks has a negative
effect on quantum-well induced ferromagnetism.


title:
The existence of a measure-preserving bijection from a unit square to a
  unit segment

abstract:
  In this paper, we prove the existence of a measure-preserving bijection from
unit square to unit segment. This bijection is also called the probability
isomorphism between two probability spaces. Then we give a new proof of the
existence of the independent random variables on Borel probability space
$([0,1],\B([0,1]),\Lb)$ that their distribution functions are the given
distribution functions.


title:
A Novel Human Computer Interaction Platform based College Mathematical
  Education Methodology

abstract:
  This article proposes the analysis on novel human computer interaction (HCI)
platform based college mathematical education methodology. Above for the
application of virtual reality technology in teaching the problems in the
study, only through the organization focus on the professional and technical
personnel, and constantly improve researchers in development process of
professional knowledge, close to the actual needs of the teaching can we
achieve the satisfactory result. To obtain better education output, we combine
the Kinect to form the HCI based teaching environment. We firstly review the
latest HCI technique and principles of college math courses, then we introduce
basic components of the Kinect including the gesture segmentation, systematic
implementation and the primary characteristics of the platform. As the further
step, we implement the system with the re-write of script code to build up the
personalized HCI assisted education scenario. The verification and simulation
proves the feasibility of our method.


title:
Spectrum Sharing Between A Surveillance Radar and Secondary Wi-Fi
  Networks

abstract:
  Co-existence between unlicensed networks that share spectrum
spatio-temporally with terrestrial (e.g. Air Traffic Control) and shipborne
radars in 3-GHz band is attracting significant interest. Similar to every
primary-secondary coexistence scenario, interference from unlicensed devices to
a primary receiver must be within acceptable bounds. In this work, we formulate
the spectrum sharing problem between a pulsed, search radar (primary) and
802.11 WLAN as the secondary. We compute the protection region for such a
search radar for a) a single secondary user (initially) as well as b) a random
spatial distribution of multiple secondary users. Furthermore, we also analyze
the interference to the WiFi devices from the radar's transmissions to estimate
the impact on achievable WLAN throughput as a function of distance to the
primary radar.


title:
Local cluster-size statistics in the critical phase of bond percolation
  on the Cayley tree

abstract:
  We study bond percolation of the Cayley tree (CT) by focusing on the
probability distribution function (PDF) of a local variable, namely, the size
of the cluster including a selected vertex. Because the CT does not have a
dominant bulk region, which is free from the boundary effect, even in the
large-size limit, the phase of the system on it is not well defined. We herein
show that local observation is useful to define the phase of such a system in
association with the well-defined phase of the system on the Bethe lattice,
that is, an infinite regular tree without boundary. Above the percolation
threshold, the PDFs of the vertex at the center of the CT (the origin) and of
the vertices near the boundary of the CT (the leaves) have different forms,
which are also dissimilar to the PDF observed in the ordinary percolating phase
of a Euclidean lattice. The PDF for the origin of the CT is bimodal: a decaying
exponential function and a system-size-dependent asymmetric peak, which obeys a
finite-size-scaling law with a fractal exponent. These modes are respectively
related to the PDFs of the finite and infinite clusters in the nonuniqueness
phase of the Bethe lattice. On the other hand, the PDF for the leaf of the CT
is a decaying power function. This is similar to the PDF observed at a critical
point of a Euclidean lattice but is attributed to the nesting structure of the
CT around the boundary.


title:
Research on Information Security Enhancement Approaches and the
  Applications on HCI Systems

abstract:
  With rapid development of computer techniques, the human computer interaction
scenarios are becoming more and more frequent. The development history of the
human-computer interaction is from a person to adapt to the computer to the
computer and continually adapt to the rapid development. Facing the process of
human-computer interaction, information system daily operation to produce huge
amounts of data, how to ensure human-computer interaction interface clear,
generated data safe and reliable, has become a problem to be solved in the
world of information. To deal with the challenging, we propose the information
security enhancement approaches and the core applications on HCI systems.
Through reviewing the other state-of-the-art methods, we propose the data
encryption system to deal with the issues that uses mixed encryption system to
make full use of the symmetric cipher algorithm encryption speed and encryption
intensity is high while the encryption of large amounts of data efficiently.
Our method could enhance the general safety of the HCI system, the experimental
result verities the feasibility and general robustness of our approach.


title: Modelling social identification and helping in evacuation simulation

abstract:
  Social scientists have criticised computer models of pedestrian streams for
their treatment of psychological crowds as mere aggregations of individuals.
Indeed most models for evacuation dynamics use analogies from physics where
pedestrians are considered as particles. Although this ensures that the results
of the simulation match important physical phenomena, such as the deceleration
of the crowd with increasing density, social phenomena such as group processes
are ignored. In particular, people in a crowd have social identities and share
those social identities with the others in the crowd. The process of self
categorisation determines norms within the crowd and influences how people will
behave in evacuation situations. We formulate the application of social
identity in pedestrian simulation algorithmically. The goal is to examine
whether it is possible to carry over the psychological model to computer models
of pedestrian motion so that simulation results correspond to observations from
crowd psychology. That is, we quantify and formalise empirical research on and
verbal descriptions of the effect of group identity on behaviour. We use
uncertainty quantification to analyse the model's behaviour when we vary
crucial model parameters. In this first approach we restrict ourselves to a
specific scenario that was thoroughly investigated by crowd psychologists and
where some quantitative data is available: the bombing and subsequent
evacuation of a London underground tube carriage on July 7th 2005.


title:
X-ray Spectral Model of Reprocessing by Smooth and Clumpy Molecular Tori
  in Active Galactic Nuclei with the MONACO framework

abstract:
  We construct an X-ray spectral model of reprocessing by a torus in an active
galactic nucleus (AGN) with a Monte Carlo simulation framework MONACO. Two
torus geometries of smooth and clumpy cases are considered and compared. In
order to reproduce a Compton shoulder accurately, MONACO includes not only free
electron scattering but also bound electron scattering. Raman and Reyleigh
scattering are also treated, and scattering cross sections dependent on
chemical states of hydrogen and helium are included. Doppler broadening by
turbulence velocity can be implemented. Our model gives consistent results with
other available models, such as MYTorus, except for differences due to
different physical parameters and assumptions. We studied the dependence on
torus parameters for Compton shoulder, and found that a intensity ratio of
Compton shoulder to line core mainly depends on the column density, inclination
angle, and metal abundance. For instance, an increase of metal abundance makes
the Compton shoulder relatively weak. Also, shape of Compton shoulder depends
on the column density. Furthermore, these dependences become different between
smooth and clumpy cases. Then, we discuss the possibility of ASTRO-H SXS
spectroscopy of Compton shoulder in AGN reflection spectra.


title: Dynamics of spinor Bose-Einstein condensate subject to dissipation

abstract:
  We investigate the internal dynamics of the spinor Bose-Einstein Condensates
subject to dissipation by solving the Lindblad master equation. It is shown
that for the condensates without dissipation its dynamics always evolve along
specific orbital in the phase space of ($n_0$, $\theta$) and display three
kinds of dynamical properties including Josephson-like oscillation,
self-trapping-like oscillation and 'running phase'. In contrast, the
condensates subject to dissipation will not evolve along the specific dynamical
orbital. If component-1 and component-(-1) dissipate in different rates, the
magnetization $m$ will not conserve and the system transits between different
dynamical regions. The dynamical properties can be exhibited in the phase space
of ($n_0$, $\theta$, $m$).


title: The balancing effect in brain-machine interaction

abstract:
  The meta analysis of Intangible Brain Machine Interaction (IMMI) data with
random number generators is re-evaluated through the application of rigorous
and recognized mathematical tools. The current analysis shows that the
statistical average of the true RNG-IMMI data is not shifted from chance by
direct mental intervention, thus refuting the IMMI hypothesis. A facet of this
general statistical behavior of true RNG-IMMI data is the statistical balancing
of scores observed in IMMI tests where binary testing conditions are adopted.
The actual dynamics that had been supporting the elusive IMMI effect are shown
to be related to the psychology of experimenters. The implications of the
refutation of the IMMI hypothesis especially on associated phenomena are also
discussed.


title:
Planck constraints on scalar-tensor cosmology and the variation of the
  gravitational constant

abstract:
  Cosmological constraints on the scalar-tensor theory of gravity by analyzing
the angular power spectrum data of the cosmic microwave background (CMB)
obtained from the Planck 2015 results are presented. We consider the harmonic
attractor model, in which the scalar field has a harmonic potential with
curvature ($\beta$) in the Einstein frame and the theory relaxes toward the
Einstein gravity with time. Analyzing the {\it TT}, {\it EE}, {\it TE} and
lensing CMB data from Planck by the Markov chain Monte Carlo method, we find
that the present-day deviation from the Einstein gravity (${\alpha_0}^2$) is
constrained as ${\alpha_0}^2<2.5\times10^{-4-4.5\beta^2}\ (95.45\% {\rm\
C.L.})$ and ${\alpha_0}^2<6.3\times10^{-4-4.5\beta^2}\ (99.99\%\ {\rm C.L.})$
for $0<\beta<0.4$. The time variation of the effective gravitational constant
between the recombination and the present epochs is constrained as $G_{\rm
rec}/G_0<1.0056\ (95.45\% {\rm\ C.L.})$ and $G_{\rm rec}/G_0<1.0115\ (99.99
\%{\rm\ C.L.})$. We also find that the constraints are little affected by
extending to nonflat cosmological models because the diffusion damping effect
revealed by Planck breaks the degeneracy of the projection effect.


title:
Linear Time Interactive Certificates for the Minimal Polynomial and the
  Determinant of a Sparse Matrix

abstract:
  Computational problem certificates are additional data structures for each
output, which can be used by a-possibly randomized-verification algorithm that
proves the correctness of each output. In this paper, we give an algorithm that
computes a certificate for the minimal polynomial of sparse or structured nxn
matrices over an abstract field, of sufficiently large cardinality, whose Monte
Carlo verification complexity requires a single matrix-vector multiplication
and a linear number of extra field operations. We also propose a novel
preconditioner that ensures irreducibility of the characteristic polynomial of
the generically preconditioned matrix. This preconditioner takes linear time to
be applied and uses only two random entries. We then combine these two
techniques to give algorithms that compute certificates for the determinant,
and thus for the characteristic polynomial, whose Monte Carlo verification
complexity is therefore also linear.


title:
Classifying spaces of degenerating mixed Hodge structures, IV: The
  fundamental diagram

abstract:
  We complete the construction of the fundamental diagram of various partial
compactifications of the moduli spaces of mixed Hodge structures with polarized
graded quotients. The diagram includes the space of nilpotent orbits, the space
of SL(2)-orbits, and the space of Borel--Serre orbits. We give amplifications
of this fundamental diagram, and amplify the relations of these spaces. We
describe how this work is useful to understand asymptotic behaviors of
Beilinson regulators and of local height parings in degeneration. We discuss
"mild degenerations" in which regulators converge.


title: The Grail theorem prover: Type theory for syntax and semantics

abstract:
  As the name suggests, type-logical grammars are a grammar formalism based on
logic and type theory. From the prespective of grammar design, type-logical
grammars develop the syntactic and semantic aspects of linguistic phenomena
hand-in-hand, letting the desired semantics of an expression inform the
syntactic type and vice versa. Prototypical examples of the successful
application of type-logical grammars to the syntax-semantics interface include
coordination, quantifier scope and extraction.This chapter describes the Grail
theorem prover, a series of tools for designing and testing grammars in various
modern type-logical grammars which functions as a tool . All tools described in
this chapter are freely available.


title: Quantum interference in topological insulator Josephson junctions

abstract:
  Using non-equilibrium Green's functions, we studied numerically the transport
properties of a Josephson junction, superconductor-topological
insulator-superconductor hybrid system. Our numerical calculation shows first
that proximity-induced superconductivity is indeed observed in the edge states
of a topological insulator adjoining two superconducting leads and second that
the special characteristics of topological insulators endow the edge states
with an enhanced proximity effect with a superconductor but do not forbid the
bulk states to do the same. In a size-dependent analysis of the local current,
it was found that a few residual bulk states can lead to measurable resistance,
whereas because these bulk states spread over the whole sample, their
contribution to the interference pattern is insignificant when the sample size
is in the micrometer range. Based on these numerical results, it is concluded
that the apparent disappearance of residual bulk states in the superconducting
interference process as described in Ref. [\onlinecite{HartNautrePhys2014f}] is
just due to the effects of size: the contribution of the topological edge
states outweighs that of the residual bulk states.


title:
Boundary Variation Diminishing (BVD) reconstruction: a new approach to
  improve Godunov scheme

abstract:
  This paper presents a new approach, so-called boundary variation diminishing
(BVD), for reconstructions that minimize the discontinuities (jumps) at cell
interfaces in Godunov type schemes. It is motivated by the observation that
diminishing the jump at the cell boundary might effectively reduce the
dissipation in numerical flux. Different from the existing practices which seek
high-order polynomials within mesh cells while assuming discontinuities being
always at the cell interfaces, we proposed a new strategy that combines a
high-order polynomial-based interpolation and a jump-like reconstruction that
allows a discontinuity being partly represented within the mesh cell rather
than at the interface. It is shown that new schemes of high fidelity for both
continuous and discontinuous solutions can be devised by the BVD guideline with
properly-chosen candidate reconstruction schemes. Excellent numerical results
have been obtained for both scalar and Euler conservation laws with
substantially improved solution quality in comparison with the existing
methods. This work provides a simple and accurate alternative of great
practical significance to the current Godunov paradigm which overly pursues the
smoothness within mesh cell under the questionable premiss that discontinuities
only appear at cell interfaces.


title:
The growth of the vorticity gradient for the two-dimensional Euler flows
  on domains with corners

abstract:
  We consider the two-dimensional Euler equations in non-smooth domains with
corners. It is shown that if the angle of the corner $\theta$ is strictly less
than $\pi/2$, the Lipschitz estimate of the vorticity at the corner is at most
single exponential growth and the upper bound is sharp. %near the stagnation
point. For the corner with the larger angle $\pi/2 < \theta <2\pi$, $\theta
\neq \pi$, we construct an example of the vorticity which loses continuity
instantaneously. For the case $\theta \le \pi/2$, the vorticity remains
continuous inside the domain. We thus identify the threshold of the angle for
the vorticity maintaining the continuity. For the borderline angle
$\theta=\pi/2$, it is also shown that the growth rate of the Lipschitz constant
of the vorticity can be double exponential, which is the same as in
Kiselev-Sverak's result (Annals of Math., 2014).


title: Early Detection of Rogue Waves Using Compressive Sensing

abstract:
  We discuss the possible usage of the compressive sampling for the early
detection of rogue waves. One of the promising techniques for the early
detection of the oceanic rogue waves is to measure the triangular Fourier
spectra which begin to appear at the early stages of their development. For the
early detection of the rogue waves it is possible to treat such a spectrum as a
sparse signal since we would mainly be interested in the high amplitude
triangular region located at the central wavenumber. Therefore compressive
sampling can be a very efficient tool for the rogue wave early warning systems.
Compressed measurements can be acquired by remote sensing techniques such as
coherent SAR which measure the ocean surface envelope or by insitu techniques
such as spectra measuring tools mounted on a ship hull or bottom mounted
pressure gauges. By employing a numerical approach we show that triangular
Fourier spectra can be sensed by compressive measurements at the early stages
of the development of rogue waves such as those in the form of Peregrine and
Akhmediev-Peregrine solitons. Our results may lead to development of the early
warning hardware systems which use the compressive sampling thus the memory
requirements for those systems can be greatly reduced.

categories: physics.flu-dyn nlin.CD physics.ao-ph physics.optics


title:
Cooperative dynamics in coupled systems of fast and slow phase
  oscillators

abstract:
  We propose a coupled system of fast and slow phase oscillators. We observe
two-step transitions to quasi-periodic motions by direct numerical simulations
of this coupled oscillator system. A low-dimensional equation for order
parameters is derived using the Ott-Antonsen ansatz. The applicability of the
ansatz is checked by the comparison of numerical results of the coupled
oscillator system and the reduced low-dimensional equation. We investigate
further several interesting phenomena in which mutual interactions between the
fast and slow oscillators play an essential role. Fast oscillations appear
intermittently as a result of excitatory interactions with slow oscillators in
a certain parameter range. Slow oscillators experience an oscillator-death
phenomenon owing to their interaction with fast oscillators. This oscillator
death is explained as a result of saddle-node bifurcation in a simple phase
equation obtained using the temporal average of the fast oscillations. Finally
we show macroscopic synchronization of the order 1:m between the slow and fast
oscillators.


title: Relativistic Signatures at the Galactic Center

abstract:
  Studies of the inner few parsecs at the Galactic Centre provide evidence of a
supermassive black hole, associated with the unusual, variable radio and
infrared source Sgr A*.
  Our major aim is the study and analysis of the physical processes responsible
for the variable emission from the compact radio source Sgr A*. In order to
understand the physics behind the observed variability, we model the time
evolution of the flare emitting region by studying light curves and spectra of
emission originating at the surface of the accretion disk, close to the event
horizon, near the marginally stable orbit of a rotating black hole.
  Here we discuss the methods used in the analysis of the time-variable
spectral features and subsequently present preliminary modeling results.


title:
Non-divergence Parabolic Equations of Second Order with Critical Drift
  in Morrey Spaces

abstract:
  We consider uniformly parabolic equations and inequalities of second order in
the non-divergence form with drift
\[-u_{t}+Lu=-u_{t}+\sum_{ij}a_{ij}D_{ij}u+\sum b_{i}D_{i}u=0\,(\geq0,\,\leq0)\]
in some domain $\Omega\subset \mathbb{R}^{n+1}$.
  We prove a variant of Aleksandrov-Bakelman-Pucci-Krylov-Tso estimate with
$L^{p}$ norm of the inhomogeneous term for some number $p<n+1$. Based on it, we
derive the growth theorems and the interior Harnack inequality. In this paper,
we will only assume the drift $b$ is in certain Morrey spaces defined below
which are critical under the parabolic scaling but not necessarily to be
bounded. This is a continuation of the work in \cite{GC}.


title:
Boundedness of Hardy-type operators with a kernel: integral weighted
  conditions for the case $0<q<1\le p<\infty$

abstract:
  Let $U:[0,\infty)^2 \to [0,\infty)$ be a~measurable kernel satisfying:
  (i) $U(x,y)$ is nonincreasing in $x$ and nondecreasing in $y$;
  (ii) there exists a~constant $\theta>0$ such that $U(x,z) \le \theta\left(
U(x,y)+U(y,z) \right)$ for all $0\le x<y<z<\infty$;
  (iii) $U(0,y)>0$ for all $y>0$.
  Let $0<q<1< p <\infty$. We prove that the weighted inequality \[ \left(
\int_0^\infty \left( \int_0^t f(x)U(x,t) dx \right)^q w(t) dt \right)^\frac 1q
\le C \left( \int_0^\infty f^p(t)v(t)dt \right)^\frac 1p \] holds for all
nonnegative measurable functions $f$ on $(0,\infty)$ if and only if \[ \left(
\int_0^\infty \left( \int_t^\infty w(x)dx \right)^\frac{r}{p} w(t) \left(
\int_0^t U^{p'}(z,t)v^{1-p'}(z) dy \right)^\frac{r}{p'} dt \right)^\frac 1r
<\infty \] and \[ \left( \int_0^\infty \left( \int_t^\infty w(x) U^q(t,x) dx
\right)^\frac{r}{p} w(t) \sup_{z\in(0,t)} U^q(z,t)\left( \int_0^z v^{1-p'}(s)
ds \right)^\frac{r}{p'} dt \right)^\frac 1r <\infty, \] where
$p':=\frac{p}{p-1}$ and $r:=\frac{pq}{p-q}$. Analogous conditions for the case
$p=1$ and for the dual version of the inequality are also presented.


title:
Multiferroic properties of uniaxially compressed orthorhombic HoMnO3
  thin films

abstract:
  Multiferroic properties of orthorhombic HoMnO3 (Pbnm space group) are
significantly modified by epitaxial compressive strain along the a-axis. We are
able to focus on the effect of strain solely along the a-axis by using an YAlO3
(010) substrate, which has only a small lattice mismatch with HoMnO3 along the
other in-plane direction (the c-axis). Multiferroic properties of strained and
relaxed HoMnO3 thin films are compared with those reported for bulk, and are
found to differ widely. A relaxed film exhibits bulk-like properties such as a
ferroelectric transition temperature of 25 K and an incommensurate
antiferromagnetic order below 39 K, with an ordering wave vector of (0 qb 0)
with qb ~ 0.41 at 10 K. A strained film becomes ferroelectric already at 37.5 K
and has an incommensurate magnetic order with qb ~ 0.49 at 10 K.


title:
Radial excitations of non-static $J=0$ black holes in
  Einstein-Maxwell-Chern-Simons gravity

abstract:
  We study the generalization of the Kerr-Newmann black hole in 5D
Einstein-Maxwell-Chern-Simons theory with free Chern-Simons coupling parameter.
These black holes possess equal magnitude angular momenta and an event horizon
of spherical topology. We focus on the extremal case with zero temperature. We
find that, when the Chern-Simons coupling is greater than two times the
supergravity case, new branches of black holes are found which violate
uniqueness. In particular, a sequence of these black holes are non-static
radially excited solutions with vanishing angular momentum. They approach the
Reissner-Nordstr\"om solution as the excitation level increases.


title: Decorated Feynman Categories

abstract:
  In [KW14], the new concept of Feynman categories was introduced to simplify
the discussion of operad--like objects. In this present paper, we demonstrate
the usefulness of this approach, by introducing the concept of decorated
Feynman categories. The procedure takes a Feynman category $\mathfrak F$ and a
functor $\mathcal O$ to a monoidal category to produce a new Feynman category
${\mathfrak F}_{dec {\mathcal O}}$. This in one swat explains the existence of
non--sigma operads, non--sigma cyclic operads, and the non--sigma--modular
operads of Markl as well as all the usual candidates simply from the category
$\mathfrak G$, which is a full subcategory of the category of graphs of [BM08].
Moreover, we explain the appearance of terminal objects noted in [Mar15]. We
can then easily extend this for instance to the dihedral case. Furthermore, we
obtain graph complexes and all other known operadic type notions from
decorating and restricting the basic Feynman category $\mathfrak G$ of
aggregates of corollas. We additionally show that the construction is
functorial. There are further geometric and number theoretic applications,
which will follow in a separate preprint.


title:
Smooth coherent Kerr frequency combs generation with broadly tunable
  pump by higher order mode suppression

abstract:
  High-Q microresonator has been suggested a promising platform for optical
frequency comb generation, via dissipative soliton formation. To achieve a
higher Q and obtain the necessary anomalous dispersion, $Si_3N_4$
microresonators made of multi-mode waveguides were previously implemented.
However, coupling between different transverse mode families in the multi-mode
waveguides results in periodic disruption of dispersion and quality factor,
introducing perturbation to dissipative soliton formation and amplitude
modulation to the corresponding spectrum. Careful choice of pump wavelength to
avoid the mode crossing region is thus critical in conventional $Si_3N_4$
microresonators. Here, we report a novel design of $Si_3N_4$ microresonator
such that single mode operation, high quality factor, and anomalous dispersion
are attained simultaneously. The microresonator is consisted of uniform single
mode waveguides in the semi-circle region, to eliminate bending induced mode
coupling, and adiabatically tapered waveguides in the straight region, to avoid
excitation of higher order modes. The intrinsic Q of the microresonator reaches
$1.36 \times 10^6$ while the GVD remains to be anomalous at $-50 fs^2/mm$. We
demonstrate, with this novel microresonator, broadband phase-locked Kerr
frequency combs with flat and smooth spectra can be generated by pumping at any
resonances in the optical C-band.


title: Nonclassical Particle Transport in 1-D Random Periodic Media

abstract:
  We investigate the accuracy of the recently proposed nonclassical transport
equation. This equation contains an extra independent variable compared to the
classical transport equation (the path-length $s$), and models particle
transport taking place in homogenized random media in which a particle's
distance-to-collision is not exponentially distributed. To solve the
nonclassical equation one needs to know the $s$-dependent ensemble-averaged
total cross section, $\Sigma_t(\mu,s)$, or its corresponding path-length
distribution function, $p(\mu,s)$. We consider a 1-D spatially periodic system
consisting of alternating solid and void layers, randomly placed in the
$x$-axis. We obtain an analytical expression for $p(\mu,s)$ and use this result
to compute the corresponding $\Sigma_t(\mu,s)$. Then, we proceed to numerically
solve the nonclassical equation for different test problems in rod geometry;
that is, particles can move only in the directions $\mu=\pm 1$. To assess the
accuracy of these solutions, we produce "benchmark" results obtained by (i)
generating a large number of physical realizations of the system, (ii)
numerically solving the transport equation in each realization, and (iii)
ensemble-averaging the solutions over all physical realizations. We show that
the numerical results validate the nonclassical model; the solutions obtained
with the nonclassical equation accurately estimate the ensemble-averaged scalar
flux in this 1-D random periodic system, greatly outperforming the widely-used
atomic mix model in most problems.


title:
Bimodality emerges from transport model calculations of heavy ion
  collisions at intermediate energy

abstract:
  This work is a continuation of our effort [Phys. Rev. C 91, 034616 (2015)] to
examine if signatures of a phase transition can be extracted from transport
model calculations of heavy ion collisions at intermediate energy. A signature
of first order phase transition is the appearance of a bimodal distribution in
$P_m(k)$ in finite systems. Here P_m(k) is the probability that the maximum of
the multiplicity distribution occurs at mass number k. Using a well-known model
for event generation (BUU plus fluctuation), we do two cases of central
collision: mass 40 on mass 40 and mass 120 on mass 120. Bimodality is seen in
both the cases. The results are quite similar to those obtained in statistical
model calculations.
  An intriguing feature is seen. We observe that at the energy where bimodality
occurs. other phase transition like signatures appear. There are breaks in
certain first order derivatives. We then examine if such breaks appear in
standard Botzmann-Uehling-Uhlenbeck (BUU) calculations without fluctuations.
They do. The implication is interesting. If first order phase transition
occurs, it may be possible to recognise that from ordinary BUU calculation.
Probably the reason this was not seen already is because this aspect was not
investigated before.


title: Hyperbolic billiards on polytopes with contracting reflection laws

abstract:
  We study billiards on polytopes in $\Rr^d$ with contracting reflection laws,
i.e. non-standard reflection laws that contract the reflection angle towards
the normal. We prove that billiards on generic polytopes are uniformly
hyperbolic provided there exists a positive integer $k$ such that for any $k$
consecutive collisions, the corresponding normals of the faces of the polytope
where the collisions took place generate $\Rr^d$. As an application of our main
result we prove that billiards on generic polytopes are uniformly hyperbolic if
either the contracting reflection law is sufficiently close to the specular or
the polytope is obtuse. Finally, we study in detail the billiard on a family of
$3$-dimensional simplexes.


title: Learning a Deep Model for Human Action Recognition from Novel Viewpoints

abstract:
  Recognizing human actions from unknown and unseen (novel) views is a
challenging problem. We propose a Robust Non-Linear Knowledge Transfer Model
(R-NKTM) for human action recognition from novel views. The proposed R-NKTM is
a deep fully-connected neural network that transfers knowledge of human actions
from any unknown view to a shared high-level virtual view by finding a
non-linear virtual path that connects the views. The R-NKTM is learned from
dense trajectories of synthetic 3D human models fitted to real motion capture
data and generalizes to real videos of human actions. The strength of our
technique is that we learn a single R-NKTM for all actions and all viewpoints
for knowledge transfer of any real human action video without the need for
re-training or fine-tuning the model. Thus, R-NKTM can efficiently scale to
incorporate new action classes. R-NKTM is learned with dummy labels and does
not require knowledge of the camera viewpoint at any stage. Experiments on
three benchmark cross-view human action datasets show that our method
outperforms existing state-of-the-art.


title:
Tuning Pairwise Potential Can Control the Fragility of Glass-Forming
  Liquids: From Tetrahedral Network to Isotropic Soft Sphere Models

abstract:
  We perform molecular dynamics simulations for a silica glass former model
proposed by Coslovich and Pastore (CP) over a wide range of densities. The
density variation can be mapped onto the change of the potential depth between
Si and O interactions of the CP model. By reducing the potential depth (or
increasing the density), the anisotropic tetrahedral network structure observed
in the original CP model transforms into the isotropic structure with the
purely repulsive soft-sphere potential. Correspondingly, the temperature
dependence of the relaxation time exhibits the crossover from the Arrhenius to
the super-Arrhenius behavior. Being able to control the fragility over a wide
range by tuning the potential of a single model system helps us to bridge the
gap between the network and isotropic glass formers and to obtain the insight
into the underlying mechanism of the fragility. We study the relationship
between the fragility and dynamical properties such as the magnitude of the
Stokes-Einstein violation and the stretch exponent in the density correlation
function. We also demonstrate that the peak of the specific heat systematically
shifts as the density increases, hinting that the fragility is correlated with
the hidden thermodynamic anomalies of the system.


title: Algebra of 2D periodic operators with local and perpendicular defects

abstract:
  We show that 2D periodic operators with local and perpendicular defects form
an algebra. We provide an algorithm of finding spectrum for such operators.
While the continuous spectral components can be computed by simple algebraic
operations on some matrix-valued functions and few number of integrations, the
discrete part is much more complicated.


title:
Perceiving Mass in Mixed Reality through Pseudo-Haptic Rendering of
  Newton's Third Law

abstract:
  In mixed reality, real objects can be used to interact with virtual objects.
However, unlike in the real world, real objects do not encounter any opposite
reaction force when pushing against virtual objects. The lack of reaction force
during manipulation prevents users from perceiving the mass of virtual objects.
Although this could be addressed by equipping real objects with force-feedback
devices, such a solution remains complex and impractical.In this work, we
present a technique to produce an illusion of mass without any active
force-feedback mechanism. This is achieved by simulating the effects of this
reaction force in a purely visual way. A first study demonstrates that our
technique indeed allows users to differentiate light virtual objects from heavy
virtual objects. In addition, it shows that the illusion is immediately
effective, with no prior training. In a second study, we measure the lowest
mass difference (JND) that can be perceived with this technique. The
effectiveness and ease of implementation of our solution provides an
opportunity to enhance mixed reality interaction at no additional cost.


title:
Multiparty Quantum Key Agreement based on Quantum Secret Direct
  Communication with GHZ states

abstract:
  Quantum Key Agreement (QKA) signifies that two or more participants together
generate a key and QKA has to satisfy the following conditions: 1 Every
participant can change the key and the key is not decided by any participant
individually. 2 Only participants can know the key; nonparticipants cannot get
the key through illegal means. Because of the condition 1 of participating
together, it makes transport inefficient in the current mainstream protocols.
They use unicast to exchange messages one by one, so it will considerably limit
transmission efficiency and increase cost time spent. This study proposes a
protocol based on Multiparty Quantum Secret Direct Communication (MQSDC) with
multicast. In addition to satisfying the above conditions, it uses multicast to
not only achieve the effect and purpose of QKA, but also to defend against
internal and external attacks at the same time. In regard to resource
consumption, this study involves linear growth and is more efficient than other
mainstream protocols which employ exponential growth.


title:
Practical Non-Linear Energy Harvesting Model and Resource Allocation in
  SWIPT Systems

abstract:
  Simultaneous wireless information and power transfer (SWIPT) is a promising
solution for enabling long-life, and self-sustainable wireless networks. In
this thesis, we propose a practical non-linear energy harvesting (EH) model and
design a resource allocation algorithm for SWIPT systems. In particular, the
algorithm design is formulated as a non-convex optimization problem for the
maximization of the total harvested power at the EH receivers subject to
quality of service (QoS) constraints for the information decoding (ID)
receivers. To circumvent the non-convexity of the problem, we transform the
corresponding non-convex sum-of-ratios objective function into an equivalent
objective function in parametric subtractive form. Furthermore, we design a
computationally efficient iterative resource allocation algorithm to obtain the
globally optimal solution. Numerical results illustrate significant performance
gain in terms of average total harvested power for the proposed non-linear EH
receiver model, when compared to the traditional linear model.\


title:
Height, Graded Relative Hyperbolicity and Quasiconvexity {\it (with
  Corrigendum)}

abstract:
  We introduce the notions of geometric height and graded (geometric) relative
hyperbolicity in this paper. We use these to characterize quasiconvexity in
hyperbolic groups, relative quasiconvexity in relatively hyperbolic groups, and
convex cocompactness in mapping class groups and $Out(F_n)$.
  Corrigendum: there is an unfortunate mistake in the statement and the proof
of Proposition 5.1. This affects one direction of the implications of the main
theorem. A correction is given, that states that given a quasi-convex subgroup
of a hyperbolic (or relatively hyperbolic) group, the graded relative
hyperbolic structure holds with respect to saturations of I-fold intersections,
that are stabilizers of limit sets of I-fold intersections.


title: Evolved stars and the origin of abundance trends in planet hosts

abstract:
  Tentative evidence that the properties of evolved stars with planets may be
different from what we know for MS hosts has been recently reported. We aim to
test whether evolved stars with planets show any chemical peculiarity that
could be related to the planet formation process. We determine in a consistent
way the metallicity and individual abundances of a large sample of evolved
(subgiants and red giants) and MS stars with and without known planetary
companions. No differences in the <[X/Fe]> vs. condensation temperature (Tc)
slopes are found between the samples of planet and non-planet hosts when all
elements are considered. However, if the analysis is restricted to only
refractory elements, differences in the Tc-slopes between stars with and
without known planets are found. This result is found to be dependent on the
stellar evolutionary stage, as it holds for MS and subgiant stars, while there
seem to be no difference between planet and non-planet hosts among the sample
of giants. A search for correlations between the Tc-slope and the stellar
properties reveals significant correlations with the stellar mass and the
stellar age. The data also suggest that differences in terms of mass and age
between MS planet and non-planet hosts may be present. Our results are well
explained by radial mixing in the Galaxy. The sample of giant contains stars
more massive and younger than their MS counterparts. This leads to a sample of
stars possibly less contaminated by stars not born in the solar neighbourhood,
leading to no chemical differences between planet and non planet hosts. The
sample of MS stars may contain more stars from the outer disc (specially the
non-planet host sample) which might led to the differences observed in the
chemical trends.


title: Algorithms for Simultaneous Pad\'e Approximations

abstract:
  We describe how to solve simultaneous Pad\'e approximations over a power
series ring $K[[x]]$ for a field $K$ using $O~(n^{\omega - 1} d)$ operations in
$K$, where $d$ is the sought precision and $n$ is the number of power series to
approximate. We develop two algorithms using different approaches. Both
algorithms return a reduced sub-bases that generates the complete set of
solutions to the input approximations problem that satisfy the given degree
constraints. Our results are made possible by recent breakthroughs in fast
computations of minimal approximant bases and Hermite Pad\'e approximations.


title: Functions of degree 4e that are not APN infinitely often

abstract:
  We prove a necessary condition for some polynomials of degree 4e (e an odd
number) to be APN over F q n for large n, and we investigate the polynomials f
of degree 12.


title: Optical Observing Conditions at Delingha Station

abstract:
  SONG is a global ground based network of 1 meter telescopes for stellar
time-domain science, an international collaboration involving many countries
across the world. In order to enable a favourable duty cycle, the SONG network
plans to create a homogeneous distribution of 4 nodes in each of the northern
and southern hemispheres. A natural possibility was building one of the
northern nodes in East Asia, preferably on the Qinghai-Tibetan Plateau. During
the last decade, a great deal of effort has been invested in searching for high
a quality site for ground based astronomy in China, since this has been one of
the major concerns for the development of Chinese astronomy. A number of sites
on the plateau have been in operation for many years, but most of them are used
only for radio astronomy, as well as small optical telescopes for applied
astronomy. Several potential sites for large optical instruments have been
identified by the plateau site survey, but as yet none of them have been
adequately quantitatively characterised. Here we present results from a
detailed multi-year study of the Delingha site, which was eventually selected
for the SONG-China node. We also describe the site monitoring system that will
allow an isolated SONG and 50BiN node to operate safely in an automated mode.


title:
A Tale of Two Consequences: Intended and Unintended Outcomes of the
  Japan TOPIX Tick Size Changes

abstract:
  We look at the effect of the tick size changes on the TOPIX 100 index names
made by the Tokyo Stock Exchange on Jan-14-2014 and Jul-22-2104. The intended
consequence of the change is price improvement and shorter time to execution.
We look at security level metrics that include the spread, trading volume,
number of trades and the size of trades to establish whether this goal is
accomplished. An unintended effect might be the reduction in execution sizes,
which would then mean that institutions with large orders would have greater
difficulty in sourcing liquidity. We look at a sample of real orders to see if
the execution costs have gone up across the orders since the implementation of
this change.
  We study the mechanisms that affect how securities are traded on an exchange,
before delving into the specifics of the TSE tick size events. Some of the
topics we explore are: The Venue Menu and How to Increase Revenue; To Automate
or Not to Automate; Microstructure under the Microscope; The Price of
Connections to High (and Faraway) Places; Speed Thrills but Kills; Pick a Size
for the Perfect Tick; TSE Tick Size Experiments, Then and Now; Sergey Bubka and
the Regulators; Bird`s Eye View; Deep Dive; Possibilities for a Deeper Dive;
Does Tick Size Matter? Tick Size Does Matter!


title: Stress relaxation, dynamics and plasticity of transient polymer networks

abstract:
  We propose a theoretical framework for dealing with a transient polymer
network undergoing small deformations, based on the rate of breaking and
re-forming of network crosslinks and the evolving elastic reference state. In
this framework, the characteristics of the deformed transient network at
microscopic and macroscopic scales are naturally unified. Microscopically, the
breakage rate of the crosslinks is affected by the local force acting on the
chain. Macroscopically, we use the classical continuum model for rubber
elasticity to describe the structure of the deformation energy, whose reference
state is defined dynamically according to when crosslinks are broken and
formed. With this, the constitutive relation can be obtained. We study three
applications of the theory in uniaxial stretching geometry: for the stress
relaxation after an instantaneous step strain is imposed, for the stress
overshoot and subsequent decay in the plastic regime when a strain ramp is
applied, and for the cycle of stretching and release. We compare the model
predictions with experimental data on stress relaxation and stress overshoot in
physically bonded thermoplastic elastomers and in vitrimer networks.


title: On Physical Web models

abstract:
  The Physical Web is a generic term describes interconnection of physical
objects and web. The Physical Web lets present physical objects in a web. There
are different ways to do that and we will discuss them in our paper. Usually,
the web presentation for a physical object could be implemented with the help
of mobile devices. The basic idea behind the Physical Web is to navigate and
control physical objects in the world surrounding mobile devices with the help
of web technologies. Of course, there are different ways to identify and
enumerate physical objects. In this paper, we describe the existing models as
well as related challenges. In our analysis, we will target objects enumeration
and navigation as well as data retrieving and programming for the Physical Web.


title: The first decade of RR Lyrae space photometric observations

abstract:
  Space-based photometric telescopes stirred up stellar astrophysics in the
last decade, and RR Lyrae stars have not been an exception from that either.
The long, quasi-continuous, high-precision data from MOST, CoRoT and Kepler
revealed a wealth of new insights about this well-known variable class. One of
the most surprising mysteries turned out to be the apparent omnipresence of a
common additional mode in all RRd and RRc stars. Moreover, fundamental-mode
stars seem to populate two distinct classes, one of which is characterized by
the presence of additional modes and/or modulation, and another limited to
strict single-mode pulsation. The presence of additional modes and multiple
modulations in RRab stars allowed us to construct Petersen diagrams for these
parameters: while the pulsation modes show clear structures according to period
ratios, there seems to be no relation between the modulation periods
themselves.


title:
The Giant Impact Simulations with Density Independent Smoothed Particle
  Hydrodynamics

abstract:
  At present, the giant impact (GI) is the most widely accepted model for the
origin of the Moon. Most of the numerical simulations of GI have been carried
out with the smoothed particle hydrodynamics (SPH) method. Recently, however,
it has been pointed out that standard formulation of SPH (SSPH) has
difficulties in the treatment of a contact discontinuity such as a core-mantle
boundary and a free surface such as a planetary surface. This difficulty comes
from the assumption of differentiability of density in SSPH. We have developed
an alternative formulation of SPH, density independent SPH (DISPH), which is
based on differentiability of pressure instead of density to solve the problem
of a contact discontinuity. In this paper, we report the results of the GI
simulations with DISPH and compare them with those obtained with SSPH. We found
that the disk properties, such as mass and angular momentum produced by DISPH
is different from that of SSPH. In general, the disks formed by DISPH are more
compact: while formation of a smaller mass moon for low-oblique impacts is
expected with DISPH, inhibition of ejection would promote formation of a larger
mass moon for high-oblique impacts. Since only the improvement of core-mantle
boundary significantly affects the properties of circumplanetary disks
generated by GI and DISPH has not been significantly improved from SSPH for a
free surface, we should be very careful when some conclusions are drawn from
the numerical simulations for GI. And it is necessary to develop the numerical
hydrodynamical scheme for GI that can properly treat the free surface as well
as the contact discontinuity.


title:
A sufficient condition for tail asymptotics of SIR distribution in
  downlink cellular networks

abstract:
  We consider the spatial stochastic model of single-tier downlink cellular
networks, where the wireless base stations are deployed according to a general
stationary point process on the Euclidean plane with general i.i.d. propagation
effects. Recently, Ganti & Haenggi (2016) consider the same general cellular
network model and, as one of many significant results, derive the tail
asymptotics of the signal-to-interference ratio (SIR) distribution. However,
they do not mention any conditions under which the result holds. In this paper,
we compensate their result for the lack of the condition and expose a
sufficient condition for the asymptotic result to be valid. We further
illustrate some examples satisfying such a sufficient condition and indicate
the corresponding asymptotic results for the example models. We give also a
simple counterexample violating the sufficient condition.


title: Diagonals of separately continuous multi-valued mappings

abstract:
  We solve a problem on a construction of a separately continuous mapping with
the given diagonal, which is the pointwise limit of a sequence of continuous
mappings valued in an equiconnected space. We construct an example of a
closed-valued separately continuous mapping $f:[0,1]^2\to \mathbb R$ with an
everywhere discontinuous diagonal. The example shows that the results on the
joint continuity point set of compact-valued separately continuous mappings can
not be generalized to the case of closed-valued mappings.


title:
The discovery and characterisation of binary central stars in planetary
  nebulae

abstract:
  Close binary central stars of planetary nebulae are key in constraining the
poorly-understood common-envelope phase of evolution, which in turn is critical
in understanding the formation of a wide-range of astrophysical phenomena
(including cataclysmic variables, low-mass X-ray binaries and supernovae type
Ia). Here, I present the results of our on-going, targeted search for
close-binaries in planetary nebulae which has led to the discovery of more than
10 new central binaries in just the last few years (almost the same as the
total discovered during the 1980s and 1990s together). This success has been
rooted in the targeted selection of objects for study, based on morphological
features deemed typical of binarity, as well as novel observing strategies
(including the employment of narrow-band filters for photometry to minimise
nebular contamination), both of which are discussed. These new discoveries,
coupled with the painstaking characterisation of both newly discovered systems
and those from the literature, mean that we are now in a position to begin to
probe the physics of the common-envelope phase.


title:
Riesz Transform Characterization and Fefferman-Stein Decomposition of
  Triebel-Lizorkin Spaces

abstract:
  Let $D\in\mathbb{N}$, $q\in[2,\infty)$ and $(\mathbb{R}^D,|\cdot|,dx)$ be the
Euclidean space equipped with the $D$-dimensional Lebesgue measure. In this
article, via an auxiliary function space $\mathrm{WE}^{1,\,q}(\mathbb R^D)$
defined via wavelet expansions, the authors establish the Riesz transform
characterization of Triebel-Lizorkin spaces $\dot{F}^0_{1,\,q}(\mathbb{R}^D)$.
As a consequence, the authors obtain the Fefferman-Stein decomposition of
Triebel-Lizorkin spaces $\dot{F}^0_{\infty,\,q'}(\mathbb{R}^D)$. Finally, the
authors give an explicit example to show that $\dot{F}^0_{1,\,q}(\mathbb{R}^D)$
is strictly contained in $\mathrm{WE}^{1,\,q}(\mathbb{R}^D)$ and, by duality,
$\mathrm{WE}^{\infty,\,q'}(\mathbb{R}^D)$ is strictly contained in
$\dot{F}^0_{\infty,\,q'}(\mathbb{R}^D)$. Although all results when $D=1$ were
obtained by C.-C. Lin et al. [Michigan Math. J. 62 (2013), 691-703], as was
pointed out by C.-C. Lin et al., the approach used in the case $D=1$ can not be
applied to the case $D\ge2$, which needs some new skills.


title: On the p-adic stability of the FGLM algorithm

abstract:
  Nowadays, many strategies to solve polynomial systems use the computation of
a Gr{\"o}bner basis for the graded reverse lexicographical ordering, followed
by a change of ordering algorithm to obtain a Gr{\"o}bner basis for the
lexicographical ordering. The change of ordering algorithm is crucial for these
strategies. We study the p-adic stability of the main change of ordering
algorithm, FGLM. We show that FGLM is stable and give explicit upper bound on
the loss of precision occuring in its execution. The variant of FGLM designed
to pass from the grevlex ordering to a Gr{\"o}bner basis in shape position is
also stable. Our study relies on the application of Smith Normal Form
computations for linear algebra.


title: GTOC8: Results and Methods of ESA Advanced Concepts Team and JAXA-ISAS

abstract:
  We consider the interplanetary trajectory design problem posed by the 8th
edition of the Global Trajectory Optimization Competition and present the
end-to-end strategy developed by the team ACT-ISAS (a collaboration between the
European Space Agency's Advanced Concepts Team and JAXA's Institute of Space
and Astronautical Science). The resulting interplanetary trajectory won 1st
place in the competition, achieving a final mission value of $J=146.33$ [Mkm].
Several new algorithms were developed in this context but have an interest that
go beyond the particular problem considered, thus, they are discussed in some
detail. These include the Moon-targeting technique, allowing one to target a
Moon encounter from a low Earth orbit; the 1-$k$ and 2-$k$ fly-by targeting
techniques, enabling one to design resonant fly-bys while ensuring a targeted
future formation plane% is acquired at some point after the manoeuvre ; the
distributed low-thrust targeting technique, admitting one to control the
spacecraft formation plane at 1,000,000 [km]; and the low-thrust optimization
technique, permitting one to enforce the formation plane's orientations as path
constraints.

categories: physics.space-ph astro-ph.IM cs.DS cs.SY


title: Free Vibrations of Axisymmetric Shells: Parabolic and Elliptic cases

abstract:
  Approximate eigenpairs (quasimodes) of axisymmetric thin elastic domains with
laterally clamped boundary conditions (Lam{\'e} system) are determined by an
asymptotic analysis as the thickness ($2\varepsilon$) tends to zero. The
departing point is the Koiter shell model that we reduce by asymptotic analysis
to a scalar modelthat depends on two parameters: the angular frequency $k$ and
the half-thickness $\varepsilon$. Optimizing $k$ for each chosen $\varepsilon$,
we find power laws for $k$ in function of $\varepsilon$ that provide the
smallest eigenvalues of the scalar reductions.Corresponding eigenpairs generate
quasimodes for the 3D Lam{\'e} system by means of several reconstruction
operators, including boundary layer terms. Numerical experiments demonstrate
that in many cases the constructed eigenpair corresponds to the first eigenpair
of the Lam{\'e} system.Geometrical conditions are necessary to this approach:
The Gaussian curvature has to be nonnegative and the azimuthal curvature has to
dominate the meridian curvature in any point of the midsurface. In this case,
the first eigenvector admits progressively larger oscillation in the angular
variable as $\varepsilon$ tends to $0$. Its angular frequency exhibits a power
law relationof the form $k=\gamma \varepsilon^{-\beta}$ with $\beta=\frac14$ in
the parabolic case (cylinders and trimmed cones), and the various $\beta$s
$\frac25$, $\frac37$, and $\frac13$ in the elliptic case.For these cases where
the mathematical analysis is applicable, numerical examples that illustrate the
theoretical results are presented.


title: Induced Gravity from Curvature Density Preserving Diffeomorphisms

abstract:
  We construct not only an induced gravity model with the restricted
diffeomorphisms, that is, transverse diffeomorphisms which preserves the
curvature density, but also that with the full diffeomorphisms. By solving the
equations of motion, it turns out that these models produce Einstein's
equations with a certain Newton's constant in addition to the constraint for
the curvature density. In the limit of the infinite Newton constant, the models
give rise to induced gravity. Moreover, we discuss cosmological solutions on
the basis of the gravitational models at hand.


title:
Spin textures on general surfaces of the correlated topological
  insulator SmB6

abstract:
  Employing the $\mathbf{k}\cdot\mathbf{p}$ expansion for a family of
tight-binding models for SmB$_6$, we analytically compute topological surface
states on a generic $(lmn)$ surface. We show how the Dirac-cone spin structure
depends on model ingredients and on the angle $\theta$ between the surface
normal and the main crystal axes. We apply the general theory to $(001)$,
$(110)$, $(111)$, and $(210)$ surfaces, for which we provide concrete
predictions for the spin pattern of surface states which we also compare with
tight-binding results. As shown in previous work, the spin pattern on a $(001)$
surface can be related to the value of mirror Chern numbers, and we explore the
possibility of topological phase transitions between states with different
mirror Chern numbers and the associated change of the spin structure of surface
states. Such transitions may be accessed by varying either the hybridization
term in the Hamiltonian or the crystal-field splitting of the low-energy $f$
multiplets, and we compute corresponding phase diagrams.


title: An analytic comparison of regularization methods for Gaussian Processes

abstract:
  Gaussian Processes (GPs) are a popular approach to predict the output of a
parameterized experiment. They have many applications in the field of Computer
Experiments, in particular to perform sensitivity analysis, adaptive design of
experiments and global optimization. Nearly all of the applications of GPs
require the inversion of a covariance matrix that, in practice, is often
ill-conditioned. Regularization methodologies are then employed with
consequences on the GPs that need to be better understood.The two principal
methods to deal with ill-conditioned covariance matrices are i) pseudoinverse
and ii) adding a positive constant to the diagonal (the so-called nugget
regularization).The first part of this paper provides an algebraic comparison
of PI and nugget regularizations. Redundant points, responsible for covariance
matrix singularity, are defined. It is proven that pseudoinverse
regularization, contrarily to nugget regularization, averages the output values
and makes the variance zero at redundant points. However, pseudoinverse and
nugget regularizations become equivalent as the nugget value vanishes. A
measure for data-model discrepancy is proposed which serves for choosing a
regularization technique.In the second part of the paper, a distribution-wise
GP is introduced that interpolates Gaussian distributions instead of data
points. Distribution-wise GP can be seen as an improved regularization method
for GPs.


title: Short loops in surfaces with a circle boundary component

abstract:
  It is a classical theorem of Loewner that the systole of a Riemannian torus
can be bounded in terms of its area. We answer a question of a similar flavor
of Robert Young showing that if $T$ is a Riemannian 2-torus with boundary in
$\mathbb R ^n$, such that the boundary curve is a standard unit circle, then
the length of the shortest non-contractible loop in $T$ is bounded in terms of
the area of $T$.


title: Infinite-horizon problems under periodicity constraint

abstract:
  We study so{\`u}e infinite-horizon optimization problems on spaces of
periodic functions for non periodic Lagrangians. The main strategy relies on
the reduction to finite horizon thanks in the introduction of an avering
operator.We then provide existence results and necessary optimality conditions
in which the corresponding averaged Lagrangian appears.


title: Dynamic Model Averaging for Bayesian Quantile Regression

abstract:
  We propose a general dynamic model averaging (DMA) approach based on
Markov-Chain Monte Carlo for the sequential combination and estimation of
quantile regression models with time-varying parameters. The efficiency and the
effectiveness of the proposed DMA approach and the MCMC algorithm are shown
through simulation studies and applications to macro-economics and finance.


title: The universal algebra generated by a power partial isometry

abstract:
  A power partial isometry (PPI) is an element $v$ of a $C^*$-algebra with the
property that every power $v^n$ is a partial isometry. The goal of this paper
is to identify the universal $C^*$-algebra generated by a PPI with (a slight
modification of) the algebra of the finite sections method for Toeplitz
operators with continuous generating function, as first described by Albrecht
B\"ottcher and Bernd Silbermann in 1983.


title:
The Electronics and Data Acquisition System for the PandaX-I Dark Matter
  Experiment

abstract:
  We describe the electronics and data acquisition system used in the first
phase of the PandaX experiment -- a 120 kg dual-phase liquid xenon dark matter
direct detection experiment in the China Jin-Ping Underground Laboratory. This
system utilized 180 channels of commercial flash ADC waveform digitizers. This
system achieved low trigger threshold ($<$1 keV electron-equivalent energy) and
low deadtime data acquistion during the entire experimental run.


title:
Temporal interactions facilitate endemicity in the
  susceptible-infected-susceptible epidemic model

abstract:
  Data of physical contacts and face-to-face communications suggest temporally
varying networks as the media on which infections take place among humans and
animals. Epidemic processes on temporal networks are complicated by complexity
of both network structure and temporal dimensions. Theoretical approaches are
much needed for identifying key factors that affect dynamics of epidemics. In
particular, what factors make some temporal networks stronger media of
infection than other temporal networks is under debate. We develop a theory to
understand the susceptible-infected-susceptible epidemic model on arbitrary
temporal networks, where each contact is used for a finite duration. We show
that temporality of networks lessens the epidemic threshold such that
infections persist more easily in temporal networks than in their static
counterparts. We further show that the Lie commutator bracket of the adjacency
matrices at different times is a key determinant of the epidemic threshold in
temporal networks. The effect of temporality on the epidemic threshold, which
depends on a data set, is approximately predicted by the magnitude of a
commutator norm.


title: On the security of the Algebraic Eraser tag authentication protocol

abstract:
  The Algebraic Eraser has been gaining prominence as SecureRF, the company
commercializing the algorithm, increases its marketing reach. The scheme is
claimed to be well-suited to IoT applications but a lack of detail in available
documentation has hampered peer-review. Recently more details of the system
have emerged after a tag authentication protocol built using the Algebraic
Eraser was proposed for standardization in ISO/IEC SC31 and SecureRF provided
an open public description of the protocol. In this paper we describe a range
of attacks on this protocol that include very efficient and practical tag
impersonation as well as partial, and total, tag secret key recovery. Most of
these results have been practically verified, they contrast with the 80-bit
security that is claimed for the protocol, and they emphasize the importance of
independent public review for any cryptographic proposal.


title: Self-Assembly of Magnetic Spheres in Strong Homogeneous Magnetic Field

abstract:
  The self-assembly in two dimensions of spherical magnets in strong magnetic
field is addressed theoretically. %% It is shown that the attraction and
assembly of parallel magnetic chains is the result of a delicate interplay of
dipole-dipole interactions and short ranged excluded volume correlations. %%
Minimal energy structures are obtained by numerical optimization procedure as
well as analytical considerations. For a small number of constitutive magnets
$N_{\rm tot}\leq26$, a straight chain is found to be stable. In the regime of
larger $N_{\rm tot}\geq27$, the magnets form \textit{two touching} chains with
equally long tails at both ends. We succeed to identify the transition from
\textit{two} to \textit{three} touching chains at $N_{\rm tot}=129$.


title: The phonon-coupling model for Skyrme forces

abstract:
  A short review on the self-consistent RPA based on a energy-density
functional of the Skyrme type is given. We also present an extension of the RPA
where the coupling of phonons to the single-particle states is considered.
Within this approach we present numerical results which are compared with data.
The self-consistent approach is compared with the Landau-Migdal theory. Here we
derive from the self-consistent $ph$ interaction, the Landau-Migdal parameters
as well as their density dependence. In the Appendix a new derivation of the
reduced matrix elements of the $ph$ interaction is presented.


title: Nef divisors for moduli spaces of complexes with compact support

abstract:
  In [BM14b], the first author and Macr\`i constructed a family of nef divisors
on any moduli space of Bridgeland-stable objects on a smooth projective variety
X. In this article, we extend this construction to the setting of any separated
scheme Y of finite type over a field, where we consider moduli spaces of
Bridgeland-stable objects on Y with compact support. We also show that the nef
divisor is compatible with the polarising ample line bundle coming from the GIT
construction of the moduli space in the special case when Y admits a tilting
bundle and the stability condition arises from a \theta-stability condition for
the endomorphism algebra.
  Our main tool generalises the work of Abramovich--Polishchuk [AP06] and
Polishchuk [Pol07]: given a t-structure on the derived category D_c(Y) on Y of
objects with compact support and a base scheme S, we construct a constant
family of t-structures on a category of objects on YxS with compact support
relative to S.


title: Neutrino oscillations and the seesaw origin of neutrino mass

abstract:
  The historical discovery of neutrino oscillations using solar and atmospheric
neutrinos, and subsequent accelerator and reactor studies, has brought neutrino
physics to the precision era. We note that CP effects in oscillation phenomena
could be difficult to extract in the presence of unitarity violation. As a
result upcoming dedicated leptonic CP violation studies should take into
account the non-unitarity of the lepton mixing matrix. Restricting
non-unitarity will shed light on the seesaw scale, and thereby guide us towards
the new physics responsible for neutrino mass generation.