title: Various probes of Dirac matter: from graphene to topological insulators

abstract:
  Graphene, the atomic-thin layer of carbon atoms, was first isolated on an
insulating substrate in 2004 by two groups in Manchester University [1, 2] and
Columbia [3]. Those milestone experiments established the Dirac nature of the
charge carriers in graphene. The same year, C.L. Kane and E.G. Mele predicted
that intrinsic spin-orbit coupling in graphene, if strong enough, would lead to
a novel state of electronic matter called the Quantum Spin Hall (QSH) state [4,
5]. The QSH state is characterized by conducting gapless edge states
circulating around an insulating bulk. Those edge states are protected from
moderate disorder and interactions by a new topological invariant of the Z_2
nature. While the strength of spin-orbit coupling is too weak in graphene, it
was soon predicted [6] and verified by transport experiments [7, 8] that the
QSH state is realized in HgTe/CdTe quantum wells. In this manuscript, I will
summarize some selected aspects of this huge field of research focused on Dirac
matter including graphene and topological insulators. By Dirac matter, we have
in mind various systems whose excitations obey a relativistic Dirac-like
equation instead of the non relativistic Schrodinger equation. This report is
mainly focused on the 2D topological insulators using graphene as a guideline.
In chapter 1, the semimetallic character of graphene is derived and the
symmetry protection of the Dirac points is discussed while chapters 2 and 3 are
devoted to Chern insulators and QSH insulators respectively.


title:
How Do We Find Early Adopters Who Will Guide a Resource Constrained
  Network Towards a Desired Distribution of Behaviors?

abstract:
  We identify influential early adopters that achieve a target behavior
distribution for a resource constrained social network with multiple costly
behaviors. This problem is important for applications ranging from collective
behavior change to corporate viral marketing campaigns. In this paper, we
propose a model of diffusion of multiple behaviors when individual participants
have resource constraints. Individuals adopt the set of behaviors that maximize
their utility subject to available resources. We show that the problem of
influence maximization for multiple behaviors is NP-complete. Thus we propose
heuristics, which are based on node degree and expected immediate adoption, to
select early adopters. We evaluate the effectiveness under three metrics:
unique number of participants, total number of active behaviors and network
resource utilization. We also propose heuristics to distribute the behaviors
amongst the early adopters to achieve a target distribution in the population.
We test our approach on synthetic and real-world topologies with excellent
results. Our heuristics produce 15-51\% increase in resource utilization over
the na\"ive approach.


title: Hyperspherical Parameterization of Unitary Matrices

abstract:
  Unitary operators are essential to quantum mechanics, however for discrete
systems larger than a qubit, it is difficult to express them in a
self-contained way. This report presents just such a description, providing a
compact, useful parameterization, with examples of physical applications.


title: A characterization of toric varieties in characteristic p

abstract:
  If $X$ is a smooth toric variety over an algebraically closed field of
positive characteristic and $L$ is an invertible sheaf on $X$, it is known that
$F_* L$, the push-forward of $L$ along the Frobenius morphism of $X$, is a
direct sum of invertible sheaves. We show that this property characterizes
smooth projective toric varieties.


title: Probing Dust Settling in Proto-planetary Disks with ALMA

abstract:
  Investigating the dynamical evolution of dust grains in proto-planetary disks
is a key issue to understand how planets should form. We identify under which
conditions dust settling can be constrained by high angular resolution
observations at mm wavelengths, and which observational strategies are suited
for such studies. Exploring a large range of models, we generate synthetic
images of disks with different degrees of dust settling, and simulate high
angular resolution (~ 0.05-0.3") ALMA observations of these synthetic disks.
The resulting data sets are then analyzed blindly with homogeneous disk models
(where dust and gas are totally mixed) and the derived disk parameters are used
as tracers of the settling factor. Our dust disks are partially resolved by
ALMA and present some specific behaviors on radial and mainly vertical
directions, which can be used to quantify the level of settling. We find out
that an angular resolution better than or equal to ~ 0.1" (using 2.3 km
baselines at 0.8mm) allows us to constrain the dust scale height and flaring
index with sufficient precision to unambiguously distinguish between settled
and non-settled disks, provided the inclination is close enough to edge-on (i
>= 75{\deg}). Ignoring dust settling and assuming hydrostatic equilibrium when
analyzing such disks affects the derived dust temperature and the radial
dependency of the dust emissivity index. The surface density distribution can
also be severely biased at the highest inclinations. However, the derived dust
properties remain largely unaffected if the disk scale height is fitted
separately. ALMA has the potential to test some of the dust settling
mechanisms, but for real disks, deviations from ideal geometry (warps, spiral
waves) may provide an ultimate limit on the dust settling detection.


title: Simulating Resilience in Transaction-Oriented Networks

abstract:
  The power of networks manifests itself in a highly non-linear amplification
of a number of effects, and their weakness - in propagation of cascading
failures. The potential systemic risk effects can be either exacerbated or
mitigated, depending on the resilience characteristics of the network. The
goals of this paper are to study some characteristics of network amplification
and resilience. We simulate random Erdos-Renyi networks and measure
amplification by varying node capacity, transaction volume, and expected
failure rates. We discover that network throughput scales almost quadratically
with respect to the node capacity and that the effects of excessive network
load and random and irreparable node faults are equivalent and almost perfectly
anticorrelated. This knowledge can be used by capacity planners to determine
optimal reliability requirements that maximize the optimal operational regions.


title:
Parameter Estimation in Two-type Continuous-state Branching Processes
  with Immigration

abstract:
  We study the estimation of two-type continuous-state branching processes with
immigration (CBI-processes). The ergodicity of the processes is proved. We also
establish the strong consistency and central limit theorems of the conditional
least squares estimators and the weighted conditional least squares estimators
of the drift and diffusion coefficients based on low frequency observations.


title:
Genetic Algorithm with a Local Search Strategy for Discovering
  Communities in Complex Networks

abstract:
  In order to further improve the performance of current genetic algorithms
aiming at discovering communities, a local search based genetic algorithm GALS
is here proposed. The core of GALS is a local search based mutation technique.
In order to overcome the drawbacks of traditional mutation methods, the paper
develops the concept of marginal gene and then the local monotonicity of
modularity function Q is deduced from each nodes local view. Based on these two
elements, a new mutation method combined with a local search strategy is
presented. GALS has been evaluated on both synthetic benchmarks and several
real networks, and compared with some presently competing algorithms.
Experimental results show that GALS is highly effective and efficient for
discovering community structure.


title:
Ant Colony Optimization with a New Random Walk Model for Community
  Detection in Complex Networks

abstract:
  Detecting communities from complex networks has recently triggered great
interest. Aiming at this problem, a new ant colony optimization strategy
building on the Markov random walks theory, which is named as MACO, is proposed
in this paper. The framework of ant colony optimization is taken as the basic
framework in this algorithm. In each iteration, a Markov random walk model is
employed as heuristic rule; all of the ants local solutions are aggregated to a
global one through an idea of clustering ensemble, which then will be used to
update a pheromone matrix. The strategy relies on the progressive strengthening
of within-community links and the weakening of between-community links.
Gradually this converges to a solution where the underlying community structure
of the complex network will become clearly visible. The proposed MACO has been
evaluated both on synthetic benchmarks and on some real-world networks, and
compared with some present competing algorithms. Experimental result has shown
that MACO is highly effective for discovering communities.


title: Point-form dynamics of quasistable states

abstract:
  We present a field theoretical model of point-form dynamics which exhibits
resonance scattering. In particular, we construct point-form Poincar\'e
generators explicitly from field operators and show that in the vector spaces
for the in-states and out-states (endowed with certain analyticity and
topological properties suggested by the structure of the $S$-matrix) these
operators integrate to furnish differentiable representations of the causal
Poincar\'e semigroup, the semidirect product of the semigroup of spacetime
translations into the forward lightcone and the group of Lorentz
transformations. We also show that there exists a class of \emph{irreducible}
representations of the Poincar\'e semigroup defined by a complex mass and a
half-integer spin. The complex mass characterizing the representation naturally
appears in the construction as the square root of the pole position of the
propagator. These representations provide a description of resonances in the
same vein as Wigner's unitary irreducible representations of the Poincar\'e
group provide a description of stable particles.


title: Fast Complex Network Clustering Algorithm Using Agents

abstract:
  Recently, the sizes of networks are always very huge, and they take on
distributed nature. Aiming at this kind of network clustering problem, in the
sight of local view, this paper proposes a fast network clustering algorithm in
which each node is regarded as an agent, and each agent tries to maximize its
local function in order to optimize network modularity defined by function Q,
rather than optimize function Q from the global view as traditional methods.
Both the efficiency and effectiveness of this algorithm are tested against
computer-generated and real-world networks. Experimental result shows that this
algorithm not only has the ability of clustering large-scale networks, but also
can attain very good clustering quality compared with the existing algorithms.
Furthermore, the parameters of this algorithm are analyzed.


title: A Diffusion Process on Riemannian Manifold for Visual Tracking

abstract:
  Robust visual tracking for long video sequences is a research area that has
many important applications. The main challenges include how the target image
can be modeled and how this model can be updated. In this paper, we model the
target using a covariance descriptor, as this descriptor is robust to problems
such as pixel-pixel misalignment, pose and illumination changes, that commonly
occur in visual tracking. We model the changes in the template using a
generative process. We introduce a new dynamical model for the template update
using a random walk on the Riemannian manifold where the covariance descriptors
lie in. This is done using log-transformed space of the manifold to free the
constraints imposed inherently by positive semidefinite matrices. Modeling
template variations and poses kinetics together in the state space enables us
to jointly quantify the uncertainties relating to the kinematic states and the
template in a principled way. Finally, the sequential inference of the
posterior distribution of the kinematic states and the template is done using a
particle filter. Our results shows that this principled approach can be robust
to changes in illumination, poses and spatial affine transformation. In the
experiments, our method outperformed the current state-of-the-art algorithm -
the incremental Principal Component Analysis method, particularly when a target
underwent fast poses changes and also maintained a comparable performance in
stable target tracking cases.


title: Antibaryonic dark matter

abstract:
  Assuming existence of (very) heavy fourth generation of quarks and antiquarks
we argue that antibaryon composed of the three heavy antiquarks can be light,
stable and invisible, hence a good candidate for the Dark matter particle. Such
opportunity allows to keep the baryon number conservation for the generation of
the visible baryon asymmetry. The dark matter particles traveling through the
ordinary matter will annihilate with nucleons inducing
proton(neutron)-decay-like events with ~5GeV energy release in outcoming
particles.


title: Holomorphic Blocks for 3d Non-abelian Partition Functions

abstract:
  The most recent studies on the supersymmetric localization reveal many
non-trivial features of supersymmetric field theories in diverse dimensions,
and 3d gauge theory provides a typical example. It was conjectured that the
index and the partition function of a 3d N=2 theory are constructed from a
single component: the holomorphic block. We prove this conjecture for
non-abelian gauge theories by computing exactly the 3d partition functions and
holomorphic blocks.


title: Poisson cohomology of two Fano threefolds

abstract:
  We study the variety of Poisson structures and compute Poisson cohomology for
two families of Fano threefolds - smooth cubic threefolds and the del Pezzo
quintic threefold. Along the way we reobtain by a different method earlier
results of Loray, Pereira and Touzet in the special case we are considering.


title: On the spectral hardening at ~> 300 keV in solar flares

abstract:
  It has been noted for a long time that the spectra of observed continuum
emissions in many solar flares are consistent with double power laws with a
hardening at energies $\sim > $ 300 keV. It is now largely believed that at
least in electron-dominated events the hardening in photon spectrum reflects an
intrinsic hardening in the source electron spectrum. In this paper, we point
out that a power law spectrum of electron with a hardening at high energies can
be explained by diffusive shock acceleration of electrons at a termination
shock with a finite width. Our suggestion is based on an early analytical work
by Drury et al., where the steady state transport equation at a shock with a
tanh profile was solved for a $p$-independent diffusion coefficient. Numerical
simulations with a $p$-dependent diffusion coefficient show hardenings in the
accelerated electron spectrum which are comparable with observations. One
necessary condition for our proposed scenario to work is that high energy
electrons resonate with the inertial range of the MHD turbulence and low energy
electrons resonate with the dissipation range of the MHD turbulence at the
acceleration site, and the spectrum of the dissipation range $\sim k^{-2.7}$. A
$\sim k^{-2.7}$ dissipation range spectrum is consistent with recent solar wind
observations.


title:
Elimination of extremal index zeroes from generic paths of closed
  1-forms

abstract:
  Let $\alpha$ be a Morse closed $1$-form of a smooth $n$-dimensional manifold
$M$. The zeroes of $\alpha$ of index $0$ or $n$ are called \emph{centers}. It
is known that every non-vanishing de Rham cohomology class $u$ contains a Morse
representative without centers. The result of this paper is the one-parameter
analogue of the last statement: every generic path $ (\alpha_t)_{t\in [0,1]}$
of closed $1$-forms in a fixed class $u\neq 0$ such that $\alpha_0, \alpha_1$
have no centers, can be modified relatively to its extremities to another such
path $ (\beta_t)_{t\in [0,1]}$ having no center at all.


title:
Heart Disease Prediction System using Associative Classification and
  Genetic Algorithm

abstract:
  Associative classification is a recent and rewarding technique which
integrates association rule mining and classification to a model for prediction
and achieves maximum accuracy. Associative classifiers are especially fit to
applications where maximum accuracy is desired to a model for prediction. There
are many domains such as medical where the maximum accuracy of the model is
desired. Heart disease is a single largest cause of death in developed
countries and one of the main contributors to disease burden in developing
countries. Mortality data from the registrar general of India shows that heart
disease are a major cause of death in India, and in Andhra Pradesh coronary
heart disease cause about 30%of deaths in rural areas. Hence there is a need to
develop a decision support system for predicting heart disease of a patient. In
this paper we propose efficient associative classification algorithm using
genetic approach for heart disease prediction. The main motivation for using
genetic algorithm in the discovery of high level prediction rules is that the
discovered rules are highly comprehensible, having high predictive accuracy and
of high interestingness values. Experimental Results show that most of the
classifier rules help in the best prediction of heart disease which even helps
doctors in their diagnosis decisions.


title:
Effects of the density-dependent weak form factors on the neutrino
  reaction via neutral current for the nucleon in nuclear medium and $^{12}$C

abstract:
  The nucleon form factors in free space are usually thought to be modified
when a nucleon is bound in a nucleus or immersed in a nuclear medium. We
investigate effects of the density-dependent axial and weak-vector form factors
on the electro-neutrino ($\nu_e$) and anti-electro-neutrino $({\bar \nu_e})$
reactions via neutral current (NC) for a nucleon in nuclear medium or $^{12}$C.
For the density-dependent form factors, we exploit the quark-meson-coupling
(QMC) model, and apply them to the $\nu_e$ and ${\bar \nu_e}$ induced reactions
by NC. About 12% decrease of the total cross section by $\nu_e$ reaction on the
nucleon is obtained at normal density, $\rho = \rho_0 \sim 0.15 {fm}^{-3} $, as
well as about 18% reduction of total ${\nu}_e$ cross section on $^{12}$C, by
the modification of the weak form factors of the bound nucleon.
  However, similarly to the charged current reaction, effects of the nucleon
property change in the ${\bar \nu}_e$ reaction reduce significantly the cross
sections about 30% for the nucleon in matter and $^{12}$C cases. Such a large
asymmetry in the ${\bar \nu}_e$ cross sections is addressed to originate from
the different helicities of ${\bar \nu}_e$ and ${\nu}_e$.


title: Spin-Transfer Torques in Helimagnets

abstract:
  We theoretically investigate current-induced magnetization dynamics in
chiral-lattice helimagnets. Spin-orbit coupling in non-centrosymmetric crystals
induces a reactive spin-transfer torque that has not been previously
considered. We demonstrate how the torque is governed by the crystal symmetry
and acts as an effective magnetic field along the current direction in cubic
B20-type crystals. The effects of the new torque are computed for
current-induced dynamics of spin-spirals and the Doppler shift of spin waves.
In current-induced spin-spiral motion, the new torque tilts the spiral
structure. The spin waves of the spiral structure are initially displaced by
the new torque, while the dispersion relation is unaffected.


title: Compass and Kitaev models -- Theory and Physical Motivations

abstract:
  Compass models are theories of matter in which the couplings between the
internal spin (or other relevant field) components are inherently spatially
(typically, direction) dependent. Compass-type interactions appear in diverse
physical systems including Mott insulators with orbital degrees of freedom
(where interactions sensitively depend on the spatial orientation of the
orbitals involved), the low energy effective theories of frustrated quantum
magnets, systems with strong spin-orbit couplings (such as the iridates),
vacancy centers, and cold atomic gases. Kitaev's models, in particular the
compass variant on the honeycomb lattice, realize basic notions of topological
quantum computing. The fundamental inter-dependence between internal (spin,
orbital, or other) and external (i.e., spatial) degrees of freedom which
underlies compass models generally leads to very rich behaviors including the
frustration of (semi-)classical ordered states on non-frustrated lattices and
to enhanced quantum effects prompting, in certain cases, the appearance of zero
temperature quantum spin liquids. As a consequence of these frustrations, new
types of symmetries and their associated degeneracies may appear. These
intermediate symmetries lie midway between the extremes of global symmetries
and local gauge symmetries and lead to effective dimensional reductions. We
review compass models in a unified manner, paying close attention to exact
consequences of these symmetries, and to thermal and quantum fluctuations that
stabilize orders via order out of disorder effects. We review non-trivial
statistics and the appearance of topological quantum orders in compass systems
in which, by virtue of their intermediate symmetry standard orders do not
arise. This is complemented by a survey of numerical results. Where appropriate
theoretical and experimental results are compared.

categories: cond-mat.str-el cond-mat.quant-gas cond-mat.stat-mech math-ph math.MP quant-ph


title: Evidence for a cosmological effect in \gamma-ray spectra of BL Lacs

abstract:
  We update the list of GeV-TeV extragalactic \gamma-ray sources using the
2-year catalog from the Fermi-LAT and recent results ground-based \gamma-ray
telescopes. Breaks in the spectra between the high energy (100 MeV <E< 300 GeV)
and the very high energy (E> 200 GeV) ranges, and their dependence on distance,
are discussed in the context of absorption on the extragalactic background
light (EBL). We calculate the size of the expected break using a model for the
EBL and compare it to the data taking into account systematic uncertainties in
the measurements. We develop a novel Bayeasian model to describe this dataset
and use it to constrain two simple models for the EBL-induced breaks.


title: Weak production of strange particles off the nucleon

abstract:
  The strange particle production off the nucleon induced by neutrinos and
antineutrinos is investigated at low and intermediate energies. We develop a
microscopic model based on the SU(3) chiral Lagrangian. The studied mechanisms
are the main source of single kaon production for (anti)neutrino energies up to
1.5 GeV. Using this model we have also studied the associated production of
kaons and hyperons. The cross sections are large enough to be measured by
experiments such as MINER$\nu$A, T2K and NO$\nu$A.


title: Strongly exponential symmetric spaces

abstract:
  We study the exponential map of connected symmetric spaces and characterize,
in terms of midpoints and of infinitesimal conditions, when it is a
diffeomorphism, generalizing the Dixmier-Saito theorem for solvable Lie groups.
We then give a geometric characterization of the (strongly) exponential
solvable symmetric spaces as those spaces for which every triangle admits a
unique double triangle. This work is motivated by Weinstein's quantization by
groupoids program applied to symmetric spaces.


title: STC: Semantic Taxonomical Clustering for Service Category Learning

abstract:
  Service discovery is one of the key problems that has been widely researched
in the area of Service Oriented Architecture (SOA) based systems. Service
category learning is a technique for efficiently facilitating service
discovery. Most approaches for service category learning are based on suitable
similarity distance measures using thresholds. Threshold selection is
essentially difficult and often leads to unsatisfactory accuracy. In this
paper, we have proposed a self-organizing based clustering algorithm called
Semantic Taxonomical Clustering (STC) for taxonomically organizing services
with self-organizing information and knowledge. We have tested the STC
algorithm on both randomly generated data and the standard OWL-S TC dataset. We
have observed promising results both in terms of classification accuracy and
runtime performance compared to existing approaches.


title: A-dependence of weak nuclear structure functions

abstract:
  Effect of nuclear medium on the weak structure functions $F_2^A(x,Q^2)$ and
$F_3^A(x,Q^2)$ have been studied using charged current (anti)neutrino deep
inelastic scattering on various nuclear targets. Relativistic nuclear spectral
function which incorporate Fermi motion, binding and nucleon correlations are
used for the calculations. We also consider the pion and rho meson cloud
contributions calculated from a microscopic model for meson-nucleus
self-energies. Using these structure functions, $F_i^A/F_i^{proton}$ and
$F_i^A/F_i^{deuteron}$(i=2,3, A=$^{12}C$, $^{16}O$, $CH$ and $H_{2}O$) are
obtained.


title:
Determination of $sin^{2}\theta_W$ using $\nu(\bar\nu)$-Nucleus
  scattering

abstract:
  We have studied nonisoscalarity and medium effects in the extraction of weak
mixing angle using Paschos and Wolfenstein relation in the iron nucleus.
Paschos and Wolfenstein(PW) relation is valid for an isoscalar target. We have
modified the PW relation for nonisoscalar target as well as incorporated the
medium effects like Pauli blocking, Fermi motion, nuclear binding energy and
pion rho cloud contributions. In our calculations we have used the relativistic
nuclear spectral function which includes nucleon correlations. Finally local
density approximation is applied to translate the numerical results to the
finite nuclei. We have studied the dependence of $sin^{2}\theta_W$ on Bjorken
variables $x$ and $y$, four momentum transfer square ($Q^2$), energy of the
neutrino and antineutrino, and effect of excess neutrons over protons in the
nuclear target.


title: DLOLIS-A: Description Logic based Text Ontology Learning

abstract:
  Ontology Learning has been the subject of intensive study for the past
decade. Researchers in this field have been motivated by the possibility of
automatically building a knowledge base on top of text documents so as to
support reasoning based knowledge extraction. While most works in this field
have been primarily statistical (known as light-weight Ontology Learning) not
much attempt has been made in axiomatic Ontology Learning (called heavy-weight
Ontology Learning) from Natural Language text documents. Heavy-weight Ontology
Learning supports more precise formal logic-based reasoning when compared to
statistical ontology learning. In this paper we have proposed a sound Ontology
Learning tool DLOL_(IS-A) that maps English language IS-A sentences into their
equivalent Description Logic (DL) expressions in order to automatically
generate a consistent pair of T-box and A-box thereby forming both regular
(definitional form) and generalized (axiomatic form) DL ontology. The current
scope of the paper is strictly limited to IS-A sentences that exclude the
possible structures of: (i) implicative IS-A sentences, and (ii) "Wh" IS-A
questions. Other linguistic nuances that arise out of pragmatics and epistemic
of IS-A sentences are beyond the scope of this present work. We have adopted
Gold Standard based Ontology Learning evaluation on chosen IS-A rich Wikipedia
documents.


title:
Finite element approximations of the stochastic mean curvature flow of
  planar curves of graphs

abstract:
  This paper develops and analyzes a semi-discrete and a fully discrete finite
element method for a one-dimensional quasilinear parabolic stochastic partial
differential equation (SPDE) which describes the stochastic mean curvature flow
for planar curves of graphs. To circumvent the difficulty caused by the low
spatial regularity of the SPDE solution, a regularization procedure is first
proposed to approximate the SPDE, and an error estimate for the regularized
problem is derived. A semi-discrete finite element method, and a space-time
fully discrete method are then proposed to approximate the solution of the
regularized SPDE problem. Strong convergence with rates are established for
both, semi- and fully discrete methods. Computational experiments are provided
to study the interplay of the geometric evolution and gradient type-noises.


title:
New solvable problems in the dynamics of a rigid body about a fixed
  point in a potential field

abstract:
  We determine the general form of the potential of the problem of motion of a
rigid body about a fixed point, which allows the angular velocity to remain
permanently in a principal plane of inertia of the body. Explicit solution of
the problem of motion is reduced to inversion of a single integral. A
several-parameter generalization of the classical case due to Bobylev and
Steklov is found. Special cases solvable in elliptic and ultraelliptic
functions of time are discussed.


title:
Europium s-process signature at close-to-solar metallicity in stardust
  SiC grains from AGB stars

abstract:
  Individual mainstream stardust silicon carbide (SiC) grains and a
SiC-enriched bulk sample from the Murchison carbonaceous meteorite have been
analyzed by the Sensitive High Resolution Ion Microprobe - Reverse Geometry
(SHRIMP-RG) for Eu isotopes. The mainstream grains are believed to have
condensed in the outflows of 1.5 to 3 Msun carbon-rich asymptotic giant branch
(AGB) stars with close-to-solar metallicity. The 151Eu fractions [fr(151Eu) =
151Eu/(151Eu+153Eu)] derived from our measurements are compared with previous
astronomical observations of carbon-enhanced metal-poor (CEMP) stars enriched
in elements made by slow neutron captures (the s-process). Despite the
difference in metallicity between the parent stars of the grains and the
metal-poor stars, the fr(151Eu) values derived from our measurements agree well
with fr(151Eu) values derived from astronomical observations. We have also
compared the SiC data with theoretical predictions of the evolution of Eu
isotopic ratios in the envelope of AGB stars. Because of the low Eu abundances
in the SiC grains, the fr(151Eu) values derived from our measurements show
large uncertainties, being in most cases larger than the difference between
solar and predicted fr(151Eu) values. The SiC aggregate yields a fr(151Eu)
value within the range observed in the single grains and provides a more
precise result (fr(151Eu) = 0.54 +/- 0.03, 95 percent conf.), but is
approximately 12 percent higher than current s-process predictions. The AGB
models can match the SiC data if we use an improved formalism to evaluate the
contribution of excited nuclear states in the calculation of the 151Sm(n,g)
stellar reaction rate.


title:
Comment on the "Create Dirac Cones in Your Favorite Materials", by
  Chia-Hui Lin and Wei Ku (arXiv:1303.4822)

abstract:
  Recently a paper by Lin and Ku \cite{lin} was posted, where the authors
propose a very interesting idea to engineer the Dirac points in material which
originally did not have such points by inducing a CDW state through
introduction of impurities like vacancy, substitution, or intercalation. In
this comment we would like to explain the appearance of the Dirac points in
such engineered structures by symmetry arguments.


title: On Transshipment Games with Identical Newsvendors

abstract:
  In a transshipment game, supply chain agents cooperate to transship surplus
products. This note studies the effect of size of transshipment coalitions on
the optimal production/order quantities. It characterizes these quantities for
transshipment games with identical newsvendors and normally distributed market
demands. It also gives a closed form formula for equal allocation in their
cores.


title: Polarization properties of 'slow' light

abstract:
  The propagation of the arbitrarily polarized pulse of the weak probe field
through the resonant medium of Lambda-type three-level atoms with degenerate
levels adiabatically driven by the coherent coupling field is considered. It is
shown that such pulse is decomposed in the medium into two orthogonally
polarized dark-state polaritons propagating with different group velocities.
The expressions for the polarizations and group velocities of these two
polaritons are obtained. The dependence of these polarizations and group
velocities on the values of the angular momenta of resonant levels, on the
polarization of the coupling field and on the initial atomic state is studied.


title:
Great antipodal sets of complex Grassmannian manifolds as designs with
  the smallest cardinalities

abstract:
  The aim of this paper is a characterization of great antipodal sets of
complex Grassmannian manifolds as certain designs with the smallest
cardinalities.


title: Habitability and Multistability in Earth-like Planets

abstract:
  We explore the potential multistability of the climate for a planet around
the habitable zone. We focus on conditions reminiscent to those of the Earth
system, but our investigation aims at presenting a general methodology for
dealing with exoplanets. We provide a thorough analysis of the non-equilibrium
thermodynamical properties of the climate system and explore, using a a
flexible climate model, how such properties depend on the energy input of the
parent star, on the infrared atmospheric opacity, and on the rotation rate. It
is possible to reproduce the multi-stability properties reminiscent of the
paleoclimatologically relevant snowball (SB) - warm (W) conditions. We then
study the thermodynamics of the W and SB states, clarifying the role of the
hydrological cycle in shaping the irreversibility and the efficiency of the W
states, and emphasizing the extreme diversity of the SB states, where dry
conditions are realized. Thermodynamics provides the clue for studying the
tipping points of the system and leads us to constructing parametrizations
where the main thermodynamic properties are expressed as functions of the
emission temperature of the planet only. Such functions are rather robust with
respect to changing the rotation rate of the planet from the current
terrestrial one to half of it. We then explore the dynamical range of slowy
rotating and phase locked planets. There is a critical rotation rate below
which the multi-stability properties are lost. Such critical rotation rate
corresponds roughly to the phase lock 2:1 condition. Therefore, if an
Earth-like planet is 1:1 phase locked with respect to the parent star, only one
climatic state would be compatible with a given set of astronomical and
astrophysical parameters. These results have relevance for the general theory
of planetary circulation and for the definition of necessary and sufficient
conditions for habitability.


title: The Two Paradigms of Software Design

abstract:
  The dominant view of design in information systems and software engineering,
the Rational Design Paradigm, views software development as a methodical,
plan-centered, approximately rational process of optimizing a design candidate
for known constraints and objectives. This paper synthesizes an Alternative
Design Paradigm, which views software development as an amethodical,
improvisational, emotional process of simultaneously framing the problem and
building artifacts to address it. These conflicting paradigms are
manifestations of a deeper philosophical conflict between rationalism and
empiricism. The paper clarifies the nature, components and assumptions of each
paradigm and explores the implications of the paradigmatic conflict for
research, practice and education.


title:
Three-body bound states in atomic mixtures with resonant p-wave
  interaction

abstract:
  We employ the Born-Oppenheimer approximation to find the effective potential
in a three-body system consisting of a light particle and two heavy ones when
the heavy-light short-range interaction potential has a resonance corresponding
to a non-zero orbital angular momentum. In the case of an exact resonance in
the p-wave scattering amplitude, the effective potential is attractive and
long-range, namely it decreases as the third power of the inter-atomic
distance. Moreover, we show that the range and power of the potential, as well
as the number of bound states are determined by the mass ratio of the particles
and the parameters of the heavy-light short-range potential.


title: Boolean sets, skew Boolean algebras and a non-commutative Stone duality

abstract:
  We describe right-hand skew Boolean algebras in terms of a class of
presheaves of sets over Boolean algebras called Boolean sets, and prove a
duality theorem between Boolean sets and etale spaces over Boolean spaces.


title: An analytical proof for the stability of Heimburg-Jackson pulses

abstract:
  This paper studies analytically the stability of solitary waves in a
generalized Boussinesq equation with quadratic-cubic nonlinearity. For general
values of two parameters a and b determining the system, unstable waves may
occur. If however, as in a situation for which this Boussinesq equation was
recently proposed as a model for pulse propagation in nerves, (a,b) belongs to
a certain natural regime, then all possible waves are stable.


title: Exact simulation of the GHZ distribution

abstract:
  John Bell has shown that the correlations entailed by quantum mechanics
cannot be reproduced by a classical process involving non-communicating
parties. But can they be simulated with the help of bounded communication? This
problem has been studied for more than two decades and it is now well
understood in the case of bipartite entanglement. However, the issue was still
widely open for multipartite entanglement, even for the simplest case, which is
the tripartite Greenberger-Horne-Zeilinger (GHZ) state. We give an exact
simulation of arbitrary independent von Neumann measurements on general
n-partite GHZ states. Our protocol requires O(n^2) bits of expected
communication between the parties, and O(n log n) expected time is sufficient
to carry it out in parallel. Furthermore, we need only an expectation of O(n)
independent unbiased random bits, with no need for the generation of continuous
real random variables nor prior shared random variables. In the case of
equatorial measurements, we improve on the prior art with a protocol that needs
only O(n log n) bits of communication and O(log^2 n) parallel time. At the cost
of a slight increase in the number of bits communicated, these tasks can be
accomplished with a constant expected number of rounds.


title: Geofence and Network Proximity

abstract:
  Many of modern location-based services are often based on an area or place as
opposed to an accurate determination of the precise location. Geo-fencing
approach is based on the observation that users move from one place to another
and then stay at that place for a while. These places can be, for example,
commercial properties, homes, office centers and so on. As per geo-fencing
approach they could be described (defined) as some geographic areas bounded by
polygons. It assumes users simply move from fence to fence and stay inside
fences for a while. In this article we replace geo-based boundaries with
network proximity rules. This new approach let us effectively deploy location
based services indoor and provide a significant energy saving for mobile
devices comparing with the traditional methods.


title:
Quasimodes and a Lower Bound on the Uniform Energy Decay Rate for
  Kerr-AdS Spacetimes

abstract:
  We construct quasimodes for the Klein-Gordon equation on the black hole
exterior of Kerr-Anti-de Sitter (Kerr-AdS) spacetimes. Such quasi-modes are
associated with time-periodic approximate solutions of the Klein Gordon
equation and provide natural candidates to probe the decay of solutions on
these backgrounds. They are constructed as the solutions of a semi-classical
non-linear eigenvalue problem arising after separation of variables, with the
(inverse of the) angular momentum playing the role of the semi-classical
parameter. Our construction results in exponentially small errors in the
semi-classical parameter. This implies that general solutions to the Klein
Gordon equation on Kerr-AdS cannot decay faster than logarithmically. The
latter result completes previous work by the authors, where a logarithmic decay
rate was established as an upper bound.


title:
Condensation and Intermittency in an Open Boundary
  Aggregation-Fragmentation Model

abstract:
  We study real space condensation in aggregation-fragmentation models where
the total mass is not conserved, as in phenomena like cloud formation and
intracellular trafficking. We study the scaling properties of the system with
influx and outflux of mass at the boundaries using numerical simulations,
supplemented by analytical results in the absence of fragmentation. The system
is found to undergo a phase transition to an unusual condensate phase,
characterized by strong intermittency and giant fluctuations of the total mass.
A related phase transition also occurs for biased movement of large masses, but
with some crucial differences which we highlight.


title:
Closed flux tubes in higher representations and their string description
  in D=2+1 SU(N) gauge theories

abstract:
  We calculate, numerically, the low-lying spectrum of closed confining flux
tubes that carry flux in different representations of SU(N). We do so for SU(6)
at beta=171, where the calculated low-energy physics is very close to the
continuum limit and, in many respects, also close to N=infinity. We focus on
the adjoint, 84, 120, k=2A,2S and k=3A,3M,3S representations and provide
evidence that the corresponding flux tubes, albeit mostly unstable, do in fact
exist. We observe that the ground state of a flux tube with momentum along its
axis appears to be well defined in all cases and is well described by the
Nambu-Goto free string spectrum, all the way down to very small lengths, just
as it is for flux tubes carrying fundamental flux. Excited states, however,
typically show very much larger deviations from Nambu-Goto than the
corresponding excitations of fundamental flux tubes and, indeed, cannot be
extracted in many cases. We discuss whether what we are seeing here are
separate stringy and massive modes or simply large corrections to energy levels
that will become string-like at larger lengths.


title:
Effect of Receive Spatial Diversity on the Degrees of Freedom Region in
  Multi-Cell Random Beamforming

abstract:
  The random beamforming (RBF) scheme, jointly applied with multi-user
diversity based scheduling, is able to achieve virtually interference-free
downlink transmissions with only partial channel state information (CSI)
available at the transmitter. However, the impact of receive spatial diversity
on the rate performance of RBF is not fully characterized yet even in a
single-cell setup. In this paper, we study a multi-cell multiple-input
multiple-output (MIMO) broadcast system with RBF applied at each base station
(BS) and either the minimum-mean-square-error (MMSE), matched filter (MF), or
antenna selection (AS) based spatial receiver employed at each mobile terminal.
We investigate the effect of different spatial diversity receivers on the
achievable sum-rate of multi-cell RBF systems subject to both the intra- and
inter-cell interferences. We first derive closed-form expressions for the
distributions of the receiver signal-to-interference-plus-noise ratio (SINR)
with different spatial diversity techniques, based on which we compare their
rate performances at finite signal-to-noise ratios (SNRs). We then investigate
the asymptotically high-SNR regime and for a tractable analysis assume that the
number of users in each cell scales in a certain order with the per-cell SNR as
SNR goes to infinity. Under this setup, we characterize the degrees of freedom
(DoF) region for multi-cell RBF systems with different types of spatial
receivers, which consists of all the achievable DoF tuples for the individual
sum-rate of all the cells. The DoF region analysis provides a succinct
characterization of the interplays among the receive spatial diversity,
multiuser diversity, spatial multiplexing gain, inter-/intra-cell
interferences, and BSs' collaborative transmission.


title: Perfectoid Spaces: A survey

abstract:
  This paper, written in relation to the Current Developments in Mathematics
2012 Conference, discusses the recent papers on perfectoid spaces. Apart from
giving an introduction to their content, it includes some open questions, as
well as complements to the results of the previous papers.


title:
Observation of a charged charmoniumlike structure in e+e- to pi+pi-J/psi
  at \sqrt{s}=4.26 GeV

abstract:
  We study the process e+e- to pi+pi-J/psi at a center-of-mass energy of 4.260
GeV using a 525 pb^{-1} data sample collected with the BESIII detector
operating at the Beijing Electron Positron Collider. The Born cross section is
measured to be (62.9\pm 1.9\pm 3.7) pb, consistent with the production of the
Y(4260). We observe a structure at around 3.9 GeV/c^2 in the \pi^\pm J/psi mass
spectrum, which we refer to as the Z_c(3900). If interpreted as a new particle,
it is unusual in that it carries an electric charge and couples to charmonium.
A fit to the \pi^\pm J/psi invariant mass spectrum, neglecting interference,
results in a mass of (3899.0\pm 3.6\pm 4.9) MeV/c^2 and a width of (46\pm 10\pm
20) MeV. Its production ratio is measured to be R=\frac{\sigma(e+e- to \pi^\pm
Z_c(3900)^\mp to pi+pi-J/psi))} {\sigma(e+e- to pi+pi-J/psi)}=(21.5\pm 3.3\pm
7.5)%. In all measurements the first errors are statistical and the second are
systematic.


title:
High Quality Requirement Engineering and Applying Priority Based Tools
  for QoS Standardization in Web Service Architecture

abstract:
  Even though there are more development to improving the Quality of Service
and requirement engineering in web services yet there is a big scarcity for its
related standardization in day to day progress leading to vast needs in its
area. Also in web service environment it always has been a big challenge to
raise the standard of Quality of Service in requirement engineering analysis.


title: Weak $\eta$ production off the nucleon

abstract:
  The weak $\eta$-meson production off the nucleon induced by (anti)neutrinos
is studied at low and intermediate energies, the range of interest for several
ongoing and future neutrino experiments. We consider Born diagrams and the
excitation of $N^\ast (1535)S_{11}$ and $N^\ast(1650)S_{11}$ resonances. The
vector part of the N-$S_{11}$ transition form factors has been obtained from
the MAID helicity amplitudes while the poorly known axial part is constrained
with the help of the partial conservation of the axial current (PCAC) and
assuming the pion-pole dominance of the pseudoscalar form factor.


title:
Application of the Monte-Carlo refractive index matching (MCRIM)
  technique to the determination of the absolute light yield of a calcium
  molybdate scintillator

abstract:
  The use of 40Ca100MoO in experimental searches for neutrinoless double beta
decay (0{\nu}DBD) relies on knowledge of fundamental scintillation properties
of the material. In this work we determine the absolute light yield of calcium
molybdate using Monte-Carlo refractive index matching technique (MCRIM). The
MCRIM technique is a combination of experiment and simulations that allows the
absolute light yield of scintillators to be determined by taking into account
effects of refraction, scattering and absorption in the material. The light
collection efficiency of the scintillator-detector assembly was simulated using
the ZEMAX ray-tracing software. By tuning the optical parameters of the
scintillation crystal, a model was derived that gives good agreement with the
experimental results. It is shown that the light collection efficiency of
scintillators increases with transmittance and scattering due to an enhanced
probability for photons to escape the crystal volume. Using MCRIM, the absolute
light yield for the 40Ca100MoO4 scintillator was found to be 7.5+-1.2 ph/keV at
room temperature. Comparative measurements using a CaWO4 scintillator as a
reference show good agreement with this result. In that way, the study
demonstrated the potential of the MCRIM technique as a tool for quantitative
characterization of scintillation materials.


title: Size and structure of an epistatic space

abstract:
  We provide quantitative estimates on the size and the structure of the
epistatic space defined in the main article, "Dynamical Correlations in the
escape strategy of Influenza A virus", EPL 101 68003.


title: Review on new physics in heavy flavors: B-meson sector

abstract:
  A brief review of theoretical aspects of new-physics searches in flavor
physics is given. Special attention is thereby devoted to B_s mixing and the
interplay of high- and low-p_T observations.


title:
Tunable frequency-stabilization of UV laser using a Hallow-Cathode Lamp
  of atomic thallium

abstract:
  A frequency-stabilized ultraviolet laser system, locked to the thallium
resonant transition of 377.5 nm, was demonstrated using a novel bichromatic
spectroscopy technique for tuning the zero-crossing laser-lock point. The
atomic thallium system is a promising candidate in atomic parity violation and
permanent electric dipole moment experiments, and its 377.5 nm 6P1/2->7S1/2
transition is important for thallium laser cooling and trapping experiment. The
pressure shift, owing to the high pressure buffer gas of the hollow-cathode
lamp, was observed using an atomic beam resonance as reference. Such a shift
was corrected by adjusting the peak ratio of the two Doppler-free saturation
profiles resulted from two pumping beams with a 130 MHz frequency difference.
The resulted frequency stability of the ultraviolet laser is ?0.5 MHz at 0.1
sec integration time. This scheme is compact and versatile for stabilizing UV
laser systems, which acquire a sub-MHz stability and frequency tunability.


title:
Effective Characterizations of Simple Fragments of Temporal Logic Using
  Carton--Michel Automata

abstract:
  We present a framework for obtaining effective characterizations of simple
fragments of future temporal logic (LTL) with the natural numbers as time
domain. The framework is based on a form of strongly unambiguous automata, also
known as prophetic automata or complete unambiguous B\"uchi automata and
referred to as Carton-Michel automata in this paper. These automata enjoy
strong structural properties, in particular, they separate the "finitary
fraction" of a regular language of infinite words from its "infinitary
fraction" in a natural fashion. Within our framework, we provide
characterizations of several natural fragments of temporal logic, where, in
some cases, no effective characterization had been known previously, and give
lower and upper bounds for their computational complexity.


title: Every conformal class contains a metric of bounded geometry

abstract:
  We show that on every manifold, every conformal class of semi-Riemannian
metrics contains a metric $g$ such that each $k$-th-order covariant derivative
of the Riemann tensor of $g$ has bounded absolute value $a_k$. This result is
new also in the Riemannian case, where one can arrange in addition that $g$ is
complete with injectivity and convexity radius greater than 1. One can even
make the radii rapidly increasing and the functions $a_k$ rapidly decreasing at
infinity. We prove generalizations to foliated manifolds, where curvature,
second fundamental form and injectivity radius of the leaves can be controlled
similarly. Moreover, we explain a general principle that can be used to obtain
analogous results for Riemannian manifolds equipped with arbitrary other
additional geometric structures instead of foliations.


title: A Faster Algorithm for Computing Motorcycle Graphs

abstract:
  We present a new algorithm for computing motorcycle graphs that runs in
O(n^(4/3+e)) time for any e>0, improving on all previously known algorithms.
The main application of this result is to computing the straight skeleton of a
polygon. It allows us to compute the straight skeleton of a non-degenerate
polygon with h holes in O(n.sqrt(h+1)log^2(n)+n^(4/3+e)) expected time. If all
input coordinates are O(log n)-bit rational numbers, we can compute the
straight skeleton of a (possibly degenerate) polygon with h holes in
O(n.sqrt(h+1)log^3(n)) expected time.
  In particular, it means that we can compute the straight skeleton of a simple
polygon in O(n.log^3(n)) expected time if all input coordinates are O(\log
n)-bit rationals, while all previously known algorithms have worst-case running
time larger than n^(3/2).


title:
Recovery of Paley-Wiener functions using scattered translates of regular
  interpolators

abstract:
  It has been shown that Paley-Wiener functions may be recovered from their
values on a complete interpolating sequence. This paper explores the same
phenomenon, and gives a sufficient condition on a function $\phi(x)$, called an
interpolator, so that scattered translates of this function may be used to
interpolate and recover any given Paley-Wiener function.


title: SYNTAGMA. A Linguistic Approach to Parsing

abstract:
  SYNTAGMA is a rule-based parsing system, structured on two levels: a general
parsing engine and a language specific grammar. The parsing engine is a
language independent program, while grammar and language specific rules and
resources are given as text files, consisting in a list of constituent
structuresand a lexical database with word sense related features and
constraints. Since its theoretical background is principally Tesniere's
Elements de syntaxe, SYNTAGMA's grammar emphasizes the role of argument
structure (valency) in constraint satisfaction, and allows also horizontal
bounds, for instance treating coordination. Notions such as Pro, traces, empty
categories are derived from Generative Grammar and some solutions are close to
Government&Binding Theory, although they are the result of an autonomous
research. These properties allow SYNTAGMA to manage complex syntactic
configurations and well known weak points in parsing engineering. An important
resource is the semantic network, which is used in disambiguation tasks.
Parsing process follows a bottom-up, rule driven strategy. Its behavior can be
controlled and fine-tuned.


title: Paper-and-pencil cosmological calculator

abstract:
  The paper-and-pencil calculator is a cosmological nomogram which allows to
find relations between redshift, distance, age of the Universe, physical and
angular sizes, luminosity and apparent magnitude for the standard cosmological
model with parameters from the Planck mission.


title: Auxiliary superfields in N=1 supersymmetric self-dual electrodynamics

abstract:
  We construct the general formulation of N=1 supersymmetric self-dual abelian
gauge theory involving auxiliary chiral spinor superfields. Self-duality in
this context is just U(N) invariance of the nonlinear interaction of the
auxiliary superfields. Focusing on the U(1) case, we present the most general
form of the U(1) invariant auxiliary interaction, consider a few instructive
examples and show how to generate self-dual N=1 models with higher derivatives
in this approach.


title: Cheeger constants and $L^2$-Betti numbers

abstract:
  We prove the existence of positive lower bounds on the Cheeger constants of
manifolds of the form $X/\Gamma$ where $X$ is a contractible Riemannian
manifold and $\Gamma<\Isom(X)$ is a discrete subgroup, typically with infinite
co-volume. The existence depends on the $L^2$-Betti numbers of $\Gamma$, its
subgroups and of a uniform lattice of $\Isom(X)$. As an application, we show
the existence of a uniform positive lower bound on the Cheeger constant of any
manifold of the form $\H^4/\Gamma$ where $\H^4$ is real hyperbolic 4-space and
$\Gamma<\Isom(\H^4)$ is discrete and isomorphic to a subgroup of the
fundamental group of a complete finite-volume hyperbolic 3-manifold. Via
Patterson-Sullivan theory, this implies the existence of a uniform positive
upper bound on the Hausdorff dimension of the conical limit set of such a
$\Gamma$ when $\Gamma$ is geometrically finite. Another application shows the
existence of a uniform positive lower bound on the zero-th eigenvalue of the
Laplacian of $\H^n/\Gamma$ over all discrete free groups $\Gamma<\Isom(\H^n)$
whenever $n\ge 4$ is even (the bound depends on $n$). This extends results of
Phillips-Sarnak and Doyle who obtained such bounds for $n\ge 3$ when $\Gamma$
is a finitely generated Schottky group.


title: L\'evy processes in storage and inventory problems

abstract:
  In this paper we consider storage and inventory systems. Our aim is to apply
and review main results of the fluctuation theory of stochastic processes in
the context of storage and inventory modeling. We describe systems where the
inflow is due to a L\'evy process and the outflow is linear and conversely
systems where the inflow is linear and the outflow is due to a L\'evy process.
For such systems we investigate the process of a storage (inventory) level. We
give formulas for the probability that the storage level exceeds a certain
value. This probability is crucial in the management of storage and inventory
systems.


title: A catalog of matchstick graphs

abstract:
  Classification of planar unit-distance graphs with up to 9 edges, by
homeomorphism and isomorphism classes. With exactly nine edges, there are 633
nonisomorphic connected matchstick graphs, of which 196 are topologically
distinct from each other. Increasing edges' number, their quantities rise more
than exponentially, in a still unclear way.


title: Time varying networks and the weakness of strong ties

abstract:
  In most social and information systems the activity of agents generates
rapidly evolving time-varying networks. The temporal variation in networks'
connectivity patterns and the ongoing dynamic processes are usually coupled in
ways that still challenge our mathematical or computational modelling. Here we
analyse a mobile call dataset and find a simple statistical law that
characterize the temporal evolution of users' egocentric networks. We encode
this observation in a reinforcement process defining a time-varying network
model that exhibits the emergence of strong and weak ties. We study the effect
of time-varying and heterogeneous interactions on the classic rumour spreading
model in both synthetic, and real-world networks. We observe that strong ties
severely inhibit information diffusion by confining the spreading process among
agents with recurrent communication patterns. This provides the
counterintuitive evidence that strong ties may have a negative role in the
spreading of information across networks.


title:
Blackbody emission from light interacting with an effective moving
  dispersive medium

abstract:
  Intense laser pulses excite a nonlinear polarisation response that may create
an effective flowing medium and, under appropriate conditions, a blocking
horizon for light. Here we analyse in detail the interaction of light with such
laser-induced flowing media, fully accounting for the medium dispersion
properties. An analytical model based on a first Born-approximation is found to
be in excellent agreement with numerical simulations based on Maxwell's
equations and shows that when a blocking horizon is formed, the stimulated
medium scatters light with a blackbody emission spectrum. Based on these
results, diamond is proposed as a promising candidate medium for future studies
of Hawking emission from artificial, dispersive horizons.


title:
Noise-induced topological transformations of vortex solitons in optical
  fibers filled with a cold atomic gas

abstract:
  We consider the influence of optical and temperature-dependent atomic
fluctuations on the formation and propagation of optical vortex solitons in
dense media realized as hollow-core optical fibers filled with a cold atomic
gas in presence of optical pumping. We show different perturbation-induced
scenaria of complete destruction and smooth transformations of the topological
characteristics of localized optical structures in hollow-core fiber. The
maximum levels of optical and atomic fluctuations at which the soliton regime
can be maintained has been determined. The estimates for these levels show an
opportunity to observe the optical vortex solitions in the core-filling gas of
the fiber for temperatures smaller than the critical temperature for
Bose-Einstein condensate.

categories: nlin.PS cond-mat.quant-gas physics.atom-ph physics.optics


title: Projective modules for the symmetric group and Young's seminormal form

abstract:
  We study the representation theory of the symmetric group $S_n$ in positive
characteristic $p$. Using features of the LLT-algorithm we give a conjectural
description of the projective cover $P(\lambda)$ of the simple module
$D(\lambda)$ where $\lambda$ is a $p$-restricted partition such that all
ladders of the corresponding ladder partition are of order less than $p$.
Inspired by the recent theory of Khovanov-Lauda-Rouquier algebras we explain an
algorithm that allows us to verify this conjectural description for $n \leq
15$, at least.


title: Random attractor associated with the quasi-geostrophic equation

abstract:
  We study the long time behavior of the solutions to the 2D stochastic
quasi-geostrophic equation on $\mathbb{T}^2$ driven by additive noise and real
linear multiplicative noise in the subcritical case (i.e. $\alpha>1/2$) by
proving the existence of a random attractor. The key point for the proof is the
exponential decay of the $L^p$-norm and a boot-strapping argument. The upper
semicontinuity of random attractors is also established. Moreover, if the
viscosity constant is large enough, the system has a trivial random attractor.


title: Log-periodic critical amplitudes: a perturbative approach

abstract:
  Log-periodic amplitudes appear in the critical behavior of a large class of
systems, in particular when a discrete scale invariance is present. Here we
show how to compute these critical amplitudes perturbatively when they
originate from a renormalization map which is close to a monomial. In this
case, the log-periodic amplitudes of the subdominant corrections to the leading
critical behavior can also be calculated.


title:
Odd-Even Embedding Scheme Based Modified Reversible Watermarking
  Technique using Blueprint

abstract:
  Digital watermarking is a technique of information adding or information
hiding in order to identify the owner of the data in multimedia content. It
seems that a signal or digital image can permanently embed over another digital
data providing a good way to protect intellectual property from illegal
replication. The cover data that is transmitted through the internet hides the
watermark in a computer aided assertion method such that it becomes
undetectable. Finally it stands as a hindrance over many operations without
harming the embedded host document. Unfortunately, many owners of the digital
materials such as images, text, audio and video are reluctant to the spreading
of their documents on the web or other networked environment, because the ease
of duplicating digital materials facilitates copyright violation. Digital media
distribution occurs through various channels. The cover data may or may not
hold any relation with the watermark information. In the last two decades, a
considerable amount of research has been done on the digital watermarking of
multimedia files such as audio, video, images and text. Different type of
watermarking algorithms has been proposed by the researchers to achieve high
level of security and authenticity. In our proposed method, a modified
reversible watermarking technique is introduced, which employs a blueprint
generation of original image based on odd-even embedding methodology to yield
large data hiding capacity, security as well as high watermarked quality. The
experimental results demonstrate that, no matter how much secret data is
embedded, the watermarked quality is about 51dB in this proposed scheme.


title: On the Jeffreys-Lindley's paradox

abstract:
  This paper discusses the dual interpretation of the Jeffreys--Lindley's
paradox associated with Bayesian posterior probabilities and Bayes factors,
both as a differentiation between frequentist and Bayesian statistics and as a
pointer to the difficulty of using improper priors while testing. We stress the
considerable impact of this paradox on the foundations of both classical and
Bayesian statistics. While assessing existing resolutions of the paradox, we
focus on a critical viewpoint of the paradox discussed by Spanos (2013) in
Philosophy of Science.


title: Automorphisms of Cayley graphs generated by transposition sets

abstract:
  Let $S$ be a set of transpositions such that the girth of the transposition
graph of $S$ is at least 5. It is shown that the automorphism group of the
Cayley graph of the permutation group $H$ generated by $S$ is the semidirect
product $R(H) \rtimes \Aut(H,S)$, where $R(H)$ is the right regular
representation of $H$ and $\Aut(H,S)$ is the set of automorphisms of $H$ that
fixes $S$ setwise. Furthermore, if the connected components of the
transposition graph of $S$ are isomorphic to each other, then $\Aut(H,S)$ is
isomorphic to the automorphism group of the line graph of the transposition
graph of $S$. This result is a common generalization of previous results by
Feng, Ganesan, Harary, Mirafzal, and Zhang and Huang. As another special case,
we obtain the automorphism group of the extended cube graph that was proposed
as a topology for interconnection networks.


title:
Self-energy effects in electronic Raman spectra of doped cuprates due to
  magnetic fluctuations

abstract:
  We present results for magnetic excitations in doped copper oxides using the
random phase approximation and itinerant electrons. In the [1,0] direction the
observed excitations resemble dispersive quasi-particles both in the normal and
superconducting state similar as in recent resonant inelastic X-ray scattering
(RIXS) experiments. In the [1,1] direction the excitations form, except for the
critical region near the antiferromagnetic wave vector ${\bf Q}=(\pi,\pi)$,
only very broad continua. Using the obtained spin propagators we calculate
electron self-energies and their effects on electronic Raman spectra. We show
that the recently observed additional peak at about twice the pair breaking in
B$_{1g}$ symmetry below T$_c$ in HgBa$_2$CuO$_{4+\delta}$ can be explained as a
self-energy effect where a broken Cooper pair and a magnetic excitation appear
as final states. The absence of this peak in B$_{2g}$ symmetry, which probes
mainly electrons near the nodal direction, is explained by their small
self-energies compared to those in the antinodal direction.


title: On Learnability, Complexity and Stability

abstract:
  We consider the fundamental question of learnability of a hypotheses class in
the supervised learning setting and in the general learning setting introduced
by Vladimir Vapnik. We survey classic results characterizing learnability in
term of suitable notions of complexity, as well as more recent results that
establish the connection between learnability and stability of a learning
algorithm.


title:
Conductivity in the Heisenberg chain with next to nearest neighbor
  interaction

abstract:
  We consider a spin chain given by the XXZ model with a weak next to nearest
neighbor perturbation which breaks its exact integrability. We prove that such
system has an ideal metallic behavior (infinite conductivity), by rigorously
establishing strict lower bounds on the zero temperature Drude weight which are
strictly positive. The proof is based on Exact Renormalization Group methods
allowing to prove the convergence of the expansions and to fully take into
account the irrelevant terms, which play an essential role in ensuring the
correct lattice symmetries. We also prove that the Drude weight verifies the
same parameter-free relations as in the absence of the integrability breaking
perturbation.


title: SPDEs with $\alpha$-stable L\'evy noise: a random field approach

abstract:
  This article is dedicated to the study of an SPDE of the form
$$Lu(t,x)=\sigma(u(t,x))\dot{Z}(t,x) \quad t>0, x \in \cO$$ with zero initial
conditions and Dirichlet boundary conditions, where $\sigma$ is a Lipschitz
function, $L$ is a second-order pseudo-differential operator, $\cO$ is a
bounded domain in $\bR^d$, and $\dot{Z}$ is an $\alpha$-stable L\'evy noise
with $\alpha \in (0,2)$, $\alpha\not=1$ and possibly non-symmetric tails. To
give a meaning to the concept of solution, we develop a theory of stochastic
integration with respect to $Z$, by generalizing the method of Gin\'e and
Marcus (1983) to higher dimensions and non-symmetric tails. The idea is to
first solve the equation with "truncated" noise $\dot{Z}_{K}$ (obtained by
removing from $Z$ the jumps which exceed a fixed value $K$), yielding a
solution $u_{K}$, and then show that the solutions $u_L,L>K$ coincide on the
event $t \leq \tau_{K}$, for some stopping times $\tau_K \uparrow \infty$ a.s.
A similar idea was used in Peszat and Zabczyk (2007) in the setting of
Hilbert-space valued processes. A major step is to show that the stochastic
integral with respect to $Z_{K}$ satisfies a $p$-th moment inequality, for $p
\in (\alpha,1)$ if $\alpha<1$, and $p \in (\alpha,2)$ if $\alpha>1$. This
inequality plays the same role as the Burkholder-Davis-Gundy inequality in the
theory of integration with respect to continuous martingales.


title:
Nucleon form factors and moments of generalized parton distributions
  using $N_f=2+1+1$ twisted mass fermions

abstract:
  We present results on the axial and the electromagnetic form factors of the
nucleon, as well as, on the first moments of the nucleon generalized parton
distributions using maximally twisted mass fermions. We analyze two N_f=2+1+1
ensembles having pion masses of 210 MeV and 354 MeV at two values of the
lattice spacing. The lattice scale is determined using the nucleon mass
computed on a total of 18 N_f=2+1+1 ensembles generated at three values of the
lattice spacing, $a$. The renormalization constants are evaluated
non-perturbatively with a perturbative subtraction of ${\cal O}(a^2)$-terms.
The moments of the generalized parton distributions are given in the $\bar{\rm
MS}$ scheme at a scale of $ \mu=2$ GeV. We compare with recent results obtained
using different discretization schemes. The implications on the spin content of
the nucleon are also discussed.


title:
Effect of Unfolding on the Spectral Statistics of Adjacency Matrices of
  Complex Networks

abstract:
  Random matrix theory is finding an increasing number of applications in the
context of information theory and communication systems, especially in studying
the properties of complex networks. Such properties include short-term and
long-term correlation. We study the spectral fluctuations of the adjacency of
networks using random-matrix theory. We consider the influence of the spectral
unfolding, which is a necessary procedure to remove the secular properties of
the spectrum, on different spectral statistics. We find that, while the spacing
distribution of the eigenvalues shows little sensitivity to the unfolding
method used, the spectral rigidity has greater sensitivity to unfolding.


title: Quantum Geometry in the Lab

abstract:
  Standard particle theory is based on quantized matter embedded in a classical
geometry. Here, a complementary model is proposed, based on classical matter --
massive bodies, without quantum properties -- embedded in a quantum geometry.
It does not describe elementary particles, but may be a better, fully
consistent quantum description for position states in laboratory-scale systems.
Gravitational theory suggests that the geometrical quantum system has an
information density of about one qubit per Planck length squared. If so, the
model here predicts that the quantum uncertainty of geometry creates a new form
of noise in the position of massive bodies, detectable by interferometers.


title:
Weighted tent spaces with Whitney averages: factorization, interpolation
  and duality

abstract:
  In this paper, we introduce a new scale of tent spaces which covers, the
(weighted) tent spaces of Coifman-Meyer-Stein and of
Hofmann-Mayboroda-McIntosh, and some other tent spaces considered by Dahlberg,
Kenig-Pipher and Auscher-Axelsson in elliptic equations. The strong
factorizations within our tent spaces, with applications to quasi-Banach
complex interpolation and to multiplier-duality theory, are established. This
way, we unify and extend the corresponding results obtained by
Coifman-Meyer-Stein, Cohn-Verbitsky and Hyt\"onen-Ros\'en.


title: A Numerical Approach to Scalar Nonlocal Conservation Laws

abstract:
  We address the study of a class of 1D nonlocal conservation laws from a
numerical point of view. First, we present an algorithm to numerically
integrate them and prove its convergence. Then, we use this algorithm to
investigate various analytical properties, obtaining evidence that usual
properties of standard conservation laws fail in the nonlocal setting.
Moreover, on the basis of our numerical integrations, we are lead to conjecture
the convergence of the nonlocal equation to the local ones, although no
analytical results are, to our knowledge, available in this context.


title:
Efficient Reinforcement Learning for High Dimensional Linear Quadratic
  Systems

abstract:
  We study the problem of adaptive control of a high dimensional linear
quadratic (LQ) system. Previous work established the asymptotic convergence to
an optimal controller for various adaptive control schemes. More recently, for
the average cost LQ problem, a regret bound of ${O}(\sqrt{T})$ was shown, apart
form logarithmic factors. However, this bound scales exponentially with $p$,
the dimension of the state space. In this work we consider the case where the
matrices describing the dynamic of the LQ system are sparse and their
dimensions are large. We present an adaptive control scheme that achieves a
regret bound of ${O}(p \sqrt{T})$, apart from logarithmic factors. In
particular, our algorithm has an average cost of $(1+\eps)$ times the optimum
cost after $T = \polylog(p) O(1/\eps^2)$. This is in comparison to previous
work on the dense dynamics where the algorithm requires time that scales
exponentially with dimension in order to achieve regret of $\eps$ times the
optimal cost.
  We believe that our result has prominent applications in the emerging area of
computational advertising, in particular targeted online advertising and
advertising in social networks.


title:
Space-Time Domain Decomposition Methods for Diffusion Problems in Mixed
  Formulations

abstract:
  This paper is concerned with global-in-time, nonoverlapping domain
decomposition methods for the mixed formulation of the diffusion problem. Two
approaches are considered: one uses the time-dependent Steklov-Poincar\'e
operator and the other uses Optimized Schwarz Waveform Relaxation (OSWR) based
on Robin transmission conditions. For each method, a mixed formulation of an
interface problem on the space-time interfaces between subdomains is derived,
and different time grids are employed to adapt to different time scales in the
subdomains. Demonstrations of the well-posedness of the subdomain problems
involved in each method and a convergence proof of the OSWR algorithm are given
for the mixed formulation. Numerical results for 2D problems with strong
heterogeneities are presented to illustrate the performance of the two methods.


title:
Efficient Stochastic Simulation of Chemical Kinetics Networks using a
  Weighted Ensemble of Trajectories

abstract:
  We apply the "weighted ensemble" (WE) simulation strategy, previously
employed in the context of molecular dynamics simulations, to a series of
systems-biology models that range in complexity from one-dimensional to a
system with 354 species and 3680 reactions. WE is relatively easy to implement,
does not require extensive hand-tuning of parameters, does not depend on the
details of the simulation algorithm, and can facilitate the simulation of
extremely rare events.
  For the coupled stochastic reaction systems we study, WE is able to produce
accurate and efficient approximations of the joint probability distribution for
all chemical species for all time t. WE is also able to efficiently extract
mean first passage times for the systems, via the construction of a
steady-state condition with feedback. In all cases studied here, WE results
agree with independent calculations, but significantly enhance the precision
with which rare or slow processes can be characterized. Speedups over
"brute-force" in sampling rare events via the Gillespie direct Stochastic
Simulation Algorithm range from ~10^12 to ~10^20 for rare states in a
distribution, and ~10^2 to ~10^4 for finding mean first passage times.

categories: q-bio.MN physics.bio-ph physics.chem-ph q-bio.QM


title:
The Chemical Evolution of Star-Forming Galaxies Over the Last 11 Billion
  Years

abstract:
  We calculate the stellar mass-metallicity relation at five epochs ranging to
z~2.3. We quantify evolution in the shape of the mass-metallicity relation as a
function of redshift; the mass-metallicity relation flattens at late times.
There is an empirical upper limit to the gas-phase oxygen abundance in
star-forming galaxies that is independent of redshift. From examination of the
mass-metallicity relation and its observed scatter we show that the flattening
at late times is a consequence of evolution in the stellar mass where galaxies
enrich to this empirical upper metallicity limit; there is also evolution in
the fraction of galaxies at a fixed stellar mass that enrich to this limit. The
stellar mass where metallicities begin to saturate is ~0.7 dex smaller in the
local universe than it is at z~0.8.


title: Reinforcement Ranking

abstract:
  We introduce a new framework for web page ranking -- reinforcement ranking --
that improves the stability and accuracy of Page Rank while eliminating the
need for computing the stationary distribution of random walks. Instead of
relying on teleportation to ensure a well defined Markov chain, we develop a
reverse-time reinforcement learning framework that determines web page
authority based on the solution of a reverse Bellman equation. In particular,
for a given reward function and surfing policy we recover a well defined
authority score from a reverse-time perspective: looking back from a web page,
what is the total incoming discounted reward brought by the surfer from the
page's predecessors? This results in a novel form of reverse-time
dynamic-programming/reinforcement-learning problem that achieves several
advantages over Page Rank based methods: First, stochasticity, ergodicity, and
irreducibility of the underlying Markov chain is no longer required for
well-posedness. Second, the method is less sensitive to graph topology and more
stable in the presence of dangling pages. Third, not only does the reverse
Bellman iteration yield a more efficient power iteration, it allows for faster
updating in the presence of graph changes. Finally, our experiments demonstrate
improvements in ranking quality.


title:
Star-forming galaxies in low-redshift clusters: Effects of environment
  on the concentration of star formation

abstract:
  We attempt to determine the dominant processes acting on star-forming disk
galaxies as a result of the cluster environment by studying the normalised
rates and radial distributions of star formation in galaxies within
low-redshift clusters. We develop indicators of different processes based on
the radial concentrations of R-band and H alpha light within each of the
galaxies studied. The tests are applied to galaxies in each of 3 environments -
cluster, supercluster (outside the cluster virial radius) and field. We develop
new diagnostic diagrams combining star-formation rate and spatial distribution
information to differentiate between stripping of outer disk gas, general gas
depletion, nuclear starbursts and galaxy-wide enhancement of star formation.
Hubble type classifications of cluster galaxies are found to correlate only
weakly with their concentration indices, whereas this correlation is strong for
non-cluster populations of disk galaxies. We identify a population of
early-type disk galaxies in the cluster population with both enhanced and
centrally-concentrated star formation compared to their field counterparts. The
enhanced cluster galaxies frequently show evidence of disturbance. A small but
non-negligible population of cluster galaxies with truncation of star formation
in their outer disks is also found.


title:
Continuous counterparts of Poisson and binomial distributions and their
  properties

abstract:
  On the basis of integral representations of Poisson and binomial distribution
functions via complete and incomplete Euler \Gamma- and B-functions, we
introduce and discuss continuous counterparts of the Poisson and binomial
distributions. The former turns out to be closely related to classical Volterra
functions as well. Under usual conditions, we also prove that the sequence of
continuous binomial distributions converges weakly to the continuous Poisson
one. At the end, we discuss a relationship between the continuous Poisson
distribution and the \Gamma-process.


title: Well separated spherical designs

abstract:
  For each $N\ge C_dt^d$ we prove the existence of a well separated spherical
$t$-design in the sphere $S^d$ consisting of $N$ points, where $C_d$ is a
constant depending only on $d$.


title: Equidistribution for meromorphic maps with dominant topological degree

abstract:
  Let f be a meromorphic self-map on a compact Kaehler manifold whose
topological degree is strictly larger than the other dynamical degrees. We show
that repelling periodic points are equidistributed with respect to the
equilibrium measure of f. We also describe the exceptional set of points whose
backward orbits are not equidistributed.


title:
Hausdorff dimension of divergent diagonal geodesics on product of finite
  volume hyperbolic spaces

abstract:
  In this article, we consider the product space of several non-compact finite
volume hyperbolic spaces, $V_1, V_2, \dots , V_k$ of dimension $n$. Let
$\mathrm{T}^1(V_i)$ denote the unit tangent bundle of $V_i$ for each $i=1,\dots
, k$, then for every $(v_1, \dots , v_k) \in \mathrm{T}^1 (V_1) \times \cdots
\times \mathrm{T}^1 (V_k)$, the diagonal geodesic flow $g_t$ is defined by $g_t
(v_1, \dots , v_k) = (g_t v_1, \dots , g_t v_k)$. And we define
$$\mathfrak{D}_k =\left\{ (v_1, \dots, v_k) \in \mathrm{T}^1 (V_1) \times
\cdots \times \mathrm{T}^1 (V_k): g_t(v_1, \dots, v_k) \text{ divergent, as }
t\rightarrow \infty\right\}. $$
  We will prove that the Hausdorff dimension of $\mathfrak{D}_k$ is equal to
$k(2n-1) - \frac{n-1}{2}$. This extends the result of Yitwah Cheung
~\cite{Cheung1}.


title: Non-symmetrizable quantum groups: defining ideals and specialization

abstract:
  Two generating sets of the defining ideal of a Nichols algebra of diagonal
type are proposed, which are then applied to study the bar involution and the
specialization problem of quantum groups associated to non-symmetrizable
generalized Cartan matrices.


title:
The all-loop integrable spin-chain for strings on AdS_3 x S^3 x T^4: the
  massive sector

abstract:
  We bootstrap the all-loop dynamic S-matrix for the homogeneous psu(1,1|2)^2
spin-chain believed to correspond to the discretization of the massive modes of
string theory on AdS_3 x S^3 x T^4. The S-matrix is the tensor product of two
copies of the su(1|1)^2 invariant S-matrix constructed recently for the
d(2,1;alpha)^2 chain, and depends on two antisymmetric dressing phases. We
write down the crossing equations that these phases have to satisfy.
Furthermore, we present the corresponding Bethe Ansatz, which differs from the
one previously conjectured, and discuss how our construction matches several
recent perturbative calculations.


title: The Thompson-Lyons transfer lemma for fusion systems

abstract:
  In this note, a generalization of the Thompson transfer lemma and its various
extensions, most recently due to Lyons, is proven in the context of saturated
fusion systems. A strengthening of Alperin's fusion theorem is also given in
this setting, following Alperin's own "up and down" fusion.


title: Inflation and deformation of conformal field theory

abstract:
  It has recently been suggested that a strongly coupled phase of inflation may
be described holographically in terms of a weakly coupled quantum field theory
(QFT). Here, we explore the possibility that the wave function of an
inflationary universe may be given by the partition function of a boundary QFT.
We consider the case when the field theory is a small deformation of a
conformal field theory (CFT), by the addition of a relevant operator O, and
calculate the primordial spectrum predicted in the corresponding holographic
inflation scenario. Using the Ward-Takahashi identity associated with Weyl
rescalings, we derive a simple relation between correlators of the curvature
perturbation and correlators of the deformation operator O at the boundary.
This is done without specifying the bulk theory of gravitation, so that the
result would also apply to cases where the bulk dynamics is strongly coupled.
We comment on the validity of the Suyama-Yamaguchi inequality, relating the
bi-spectrum and tri-spectrum of the curvature perturbation.


title: A characterization of the 2-fusion system of L_4(q)

abstract:
  We study a saturated fusion system F on a finite 2-group S having a Baumann
component based on a dihedral 2-group. Assuming F is 2-perfect with no
nontrivial normal 2-subgroups, and the centralizer of the component is a cyclic
2-group, it is shown that F is uniquely determined as the 2-fusion system of
L_4(q_1) for some q_1 = 3 (mod 4). This should be viewed as a contribution to a
program recently outlined by M. Aschbacher for the classification of simple
fusion systems at the prime 2. The corresponding problem in the component-type
portion of the classification of finite simple groups (the L_2(q), A_7 standard
form problem) was one of the last to be completed, and was ultimately only
resolved in an inductive context with heavy artillery. Thanks primarily to
requiring the component to be Baumann, our main arguments by contrast require
only 2-fusion analysis and transfer. We deduce a companion result in the
category of groups.


title: Complete r-partite graphs determined by their domination polynomial

abstract:
  The domination polynomial of a graph is the polynomial whose coefficients
count the number of dominating sets of each cardinality. A recent question asks
which graphs are uniquely determined (up to isomorphism) by their domination
polynomial. In this paper, we completely describe the complete r-partite graphs
which are; in the bipartite case, this settles in the affirmative a conjecture
of Aalipour, Akbari and Ebrahimi.


title: Scale-dependent bias from multiple-field inflation

abstract:
  We provide a formula for the scaling behaviour of the inflationary bispectrum
in the 'squeezed' limit where one momentum becomes much smaller than the other
two. This determines the scaling of the halo bias at low wavenumber and will be
an important observable for the next generation of galaxy surveys. Our formula
allows it to be predicted for the first time for a generic inflationary model
with multiple light, canonically-normalized scalar fields.


title: Generalizing k-means for an arbitrary distance matrix

abstract:
  The original k-means clustering method works only if the exact vectors
representing the data points are known. Therefore calculating the distances
from the centroids needs vector operations, since the average of abstract data
points is undefined. Existing algorithms can be extended for those cases when
the sole input is the distance matrix, and the exact representing vectors are
unknown. This extension may be named relational k-means after a notation for a
similar algorithm invented for fuzzy clustering. A method is then proposed for
generalizing k-means for scenarios when the data points have absolutely no
connection with a Euclidean space.


title: On the syzygies of reducible curves

abstract:
  A theorem of Green says that a line bundle of degree at least $2g+1+p$ on a
smooth curve $X$ of genus $g$ has property $N_p$. We prove a similar conclusion
for certain singular, reducible curves $X$ under suitable degree bounds over
all irreducible components of $X$.


title:
Stabilizers of quadratic points on the Bruhat-Tits tree of SL(2) over
  finite extensions of Q2

abstract:
  For F, a finite extension of Q2, and E a quadratic extension of F, I compute
the stabilizer in SL(2,F} of a point in the Bruhat-Tits tree of SL(2,E).


title: Synthetic Gauge Field with Highly Magnetic Lanthanide Atoms

abstract:
  We present a scheme for generating a synthetic magnetic field and spin-orbit
coupling via Raman coupling in highly magnetic lanthanide atoms such as
dysprosium. Employing these atoms offer several advantages for realizing
strongly correlated states and exotic spinor phases. The large spin and narrow
optical transitions of these atoms allow the generation of synthetic magnetic
fields an order of magnitude larger than those in the alkalis, but with
considerable reduction of the heating rate for equal Raman coupling. The
effective hamiltonian of these systems differs from that of the alkalis' by an
additional nematic coupling term, which leads to a phase transition in the
dressed states as detuning varies. For \text{high-spin} condensates, spin-orbit
coupling leads to a spatially periodic structure, which is described in
Majorana representation by a set of points moving periodically on a unit
sphere. We name this a "Majorana spinor helix" in analogy to the persistent
spin-1/2 helix observed in electronic systems.


title:
Commutator estimates in Besov-Morrey spaces with applications to the
  well-posedness of the Euler equations and ideal MHD system

abstract:
  We develop commutator estimates in the framework of Besov-Morrey spaces,
which are modeled on Besov spaces and the underlying norm is of Morrey space
rather than the usual $L^{p}$ space. As direct applications of commutator
estimates, we establish the local well-posedness and blow-up criterion of
solutions in Besov-Morrey spaces for the incompressible Euler equations and
ideal MHD system. Main analysis tools are the Littlewood-Paley decomposition
and Bony's para-product formula.


title:
Resistive transition in frustrated Josephson-junction arrays on a
  honeycomb lattice

abstract:
  We use driven Monte Carlo dynamics to study the resistive behavior of
superconducting Josephson junction arrays on a honeycomb lattice in a magnetic
field corresponding to $f$ flux quantum per plaquette. While for $f=1/3$ the
onset of zero resistance is found at nonzero temperature, for $f=1/2$ the
results are consistent with a transition scenario where the critical
temperature vanishes and the linear resistivity shows thermally activated
behavior. We determine the thermal critical exponent of the zero-temperature
transition for $f=1/2$, from a dynamic scaling analysis of the nonlinear
resistivity. The resistive behavior agrees with recent results obtained for the
phase-coherence transition from correlation length calculations and with
experimental observations on ultra-thin superconducting films with a triangular
pattern of nanoholes.


title: On the Possibility of Quantum Informational Structural Realism

abstract:
  In The Philosophy of Information (2011 book), Luciano Floridi presents an
ontological theory of Being qua Being, which he calls "Informational Structural
Realism", a theory which applies, he says, to every possible world. He
identifies primordial information ("dedomena") as the foundation of any
structure in any possible world. The present essay examines Floridi's defense
of that theory, as well as his refutation of "Digital Ontology" (which some
people might confuse with his own). Then, using Floridi's ontology as a
starting point, the present essay adds quantum features to dedomena, yielding
an ontological theory for our own universe, Quantum Informational Structural
Realism, which provides a metaphysical interpretation of key quantum phenomena,
and diminishes the "weirdness" or "spookiness" of quantum mechanics. Key Words:
digital ontology, dedomena, structural realism, quantum information, primordial
qubit


title: Relaxation limit in larger Besov spaces for compressible Euler equations

abstract:
  The work is devoted to the relaxation limit in larger Besov spaces for
compressible Euler equations, which contains previous results in Sobolev spaces
and Besov spaces with critical regularity. Such an extension depends on a
revision of commutator estimates and an elementary fact which indicates the
connection between homogeneous and inhomogeneous Chemin-Lerner spaces.


title:
Ultrabroadband nonreciprocal transverse energy flow of light in linear
  passive photonic circuits

abstract:
  Using a technique, analogous to coherent population trapping in an atomic
system, we propose schemes to create transverse light propagation violating
left-right symmetry in a photonic circuit consisting of three coupled
waveguides. The frequency windows for the symmetry breaking of the left-right
energy flow span over 80 nm. Our proposed system only uses linear passive
optical materials and is easy to integrate on a chip.


title: A Search for the Rare Decays B --> pi l+l- and B0 --> eta l+l-

abstract:
  We present the results of a search for the rare flavor-changing
neutral-current decays B --> pi l+l- (pi=pi+/-, pi0 and l = e,mu) and B0 -->
eta l+l- using a sample of e+e- --> Y(4S) BB decays decays corresponding to 428
fb^-1 of integrated luminosity collected by the BABAR detector. No significant
signal is observed, and we set an upper limit on the isospin and lepton-flavor
averaged branching fraction of BF(B --> pi l+l-) < 7.0 x 10^-8 and a
lepton-flavor averaged upper limit of BF(B0 --> eta l+l-) < 9.2 x 10^-8, both
at the 90% confidence level. We also report 90% confidence level branching
fraction upper limits for the individual modes B+ --> pi+ e+e-, B0 --> pi0
e+e-, B+ --> pi+ mu+mu-, B0 --> pi0 mu+mu-, B0 --> eta e+e-, and B0 --> eta
mu+mu-.


title:
The inverse function theorem and the resolution of the Jacobian
  conjecture in free analysis

abstract:
  We establish an invertibility criterion for free polynomials and free
functions evaluated on some tuples of matrices. We show that if the derivative
is nonsingular on some domain closed with respect to direct sums and
similarity, the function must be invertible. Thus, as a corollary, we establish
the Jacobian conjecture in this context. Furthermore, our result holds for
commutative polynomials evaluated on tuples of commuting matrices.


title:
Are the Snapshot Difference Quotients Needed in the Proper Orthogonal
  Decomposition?

abstract:
  This paper presents a theoretical and numerical investigation of the
following practical question: Should the time difference quotients of the
snapshots be used to generate the proper orthogonal decomposition basis
functions? The answer to this question is important, since some published
numerical studies use the time difference quotients, whereas other numerical
studies do not. The criterion used in this paper to answer this question is the
rate of convergence of the error of the reduced order model with respect to the
number of proper orthogonal decomposition basis functions. Two cases are
considered: the no_DQ case, in which the snapshot difference quotients are not
used, and the DQ case, in which the snapshot difference quotients are used. The
error estimates suggest that the convergence rates in the $C^0(L^2)$-norm and
in the $C^0(H^1)$-norm are optimal for the DQ case, but suboptimal for the
no_DQ case. The convergence rates in the $L^2(H^1)$-norm are optimal for both
the DQ case and the no_DQ case. Numerical tests are conducted on the heat
equation and on the Burgers equation. The numerical results support the
conclusions drawn from the theoretical error estimates. Overall, the
theoretical and numerical results strongly suggest that, in order to achieve
optimal pointwise in time rates of convergence with respect to the number of
proper orthogonal decomposition basis functions, one should use the snapshot
difference quotients.


title: Curve neighborhoods of Schubert varieties

abstract:
  A previous result of the authors with Chaput and Perrin states that the union
of all rational curves of fixed degree passing through a Schubert variety in a
homogeneous space G/P is again a Schubert variety. In this paper we identify
this Schubert variety explicitly in terms of the Hecke product of Weyl group
elements. We apply our result to give an explicit formula for any two-point
Gromov-Witten invariant as well as a new proof of the quantum Chevalley formula
and its equivariant generalization. We also recover a formula for the minimal
degree of a rational curve between two given points in a cominuscule variety.


title: Tilting and Refined Donaldson-Thomas Invariants

abstract:
  We study tilting for the heart A of the canonical t-structure of the
finite-dimensional derived category of the Ginzburg algebra for a quiver with
potential (Q,W). We give conditions on that the stable objects for a central
charge on A define a sequence of simple tilts from A to A[-1]. On that
conditions the refined Donaldson-Thomas invariant associated to (Q,W) is
independent of the chosen central charge.


title:
Widely tunable single photon source with high purity at telecom
  wavelength

abstract:
  We theoretically and experimentally investigate the spectral tunability and
purity of photon pairs generated from spontaneous parametric down conversion in
periodically poled $\mathrm{KTiOPO_4}$ crystal with group-velocity matching
condition. The numerical simulation predicts that the purity of joint spectral
intensity ($P_{JSI}$) and the purity of joint spectral amplitude ($P_{JSA}$)
can be kept higher than 0.98 and 0.81, respectively, when the wavelength is
tuned from 1460 nm to 1675 nm, which covers the S-, C-, L-, and U-band in
telecommunication wavelengths. We also directly measured the joint spectral
intensity at 1565 nm, 1584 nm and 1565 nm, yielding $P_{JSI}$ of 0.989, 0.983
and 0.958, respectively. Such a photon source is useful for quantum information
and communication systems.