title: Asymptotic properties of extremal K\"ahler metrics of Poincar\'e type

abstract:
  Consider a compact K\"ahler manifold X with a simple normal crossing divisor
D, and define Poincar\'e type metrics on X\D as K\"ahler metrics on X\D with
cusp singularities along D. We prove that the existence of a constant scalar
curvature (resp. an extremal) Poincar\'e type K\"ahler metric on X\D implies
the existence of a constant scalar curvature (resp. an extremal) K\"ahler
metric, possibly of Poincar\'e type, on every component of D. We also show that
when the divisor is smooth, the constant scalar curvature/extremal metric on
X\D is asymptotically a product near the divisor.


title:
Mean field approximation for biased diffusion on Japanese inter-firm
  trading network

abstract:
  By analysing the financial data of firms across Japan, a nonlinear power law
with an exponent of 1.3 was observed between the number of business partners
(i.e. the degree of the inter-firm trading network) and sales. In a previous
study using numerical simulations, we found that this scaling can be explained
by both the money-transport model, where a firm (i.e. customer) distributes
money to its out-edges (suppliers) in proportion to the in-degree of
destinations, and by the correlations among the Japanese inter-firm trading
network. However, in this previous study, we could not specifically identify
what types of structure properties (or correlations) of the network determine
the 1.3 exponent. In the present study, we more clearly elucidate the
relationship between this nonlinear scaling and the network structure by
applying mean-field approximation of the diffusion in a complex network to this
money-transport model. Using theoretical analysis, we obtained the mean-field
solution of the model and found that, in the case of the Japanese firms, the
scaling exponent of 1.3 can be determined from the power law of the average
degree of the nearest neighbours of the network with an exponent of -0.7.


title:
Spaces with labelled partitions and isometric affine actions on Banach
  spaces

abstract:
  We define the structure of spaces with labelled partitions which generalizes
the structure of spaces with measured walls and study the link between actions
by automorphisms on spaces with labelled partitions and isometric affine
actions on Banach spaces, and more particularly, on $L^p$ spaces. We build
natural spaces with labelled partitions for the action of various contructions
of groups, namely: direct sum; semi-direct product; wreath product and
amalgamated free product. We apply this to prove that the wreath product of a
group with property $PL^p$ by a group with Haagerup property has property
$PL^p$ and the amalgamated free product over finite subgroups of groups with
property $PL^p$ has property $PL^p$.


title: Topological conjugacy of constant length substitution dynamical systems

abstract:
  Primitive constant length substitutions generate minimal symbolic dynamical
systems. In this article we present an algorithm which can produce the list of
injective substitutions of the same length that generate topologically
conjugate systems.
  We show that each conjugacy class contains infinitely substitutions which are
not injective. As examples, the Toeplitz conjugacy class contains three
injective substitutions (two on two symbols and one on three symbols), and the
length two Thue-Morse conjugacy class contains twelve substitutions, among
which are two on six symbols. Together, they constitute a list of all primitive
substitutions of length two with infinite minimal systems which are factors of
the Thue-Morse system.


title:
A simple mathematical approach to optimize the structure of
  reaction-diffusion physicochemical systems

abstract:
  The calculation of optimal structures in reaction-diffusion models is of
great importance in many physicochemical systems. We propose here a simple
method to monitor the number of interphases for long times by using a boundary
flux condition as a control. We consider as an illustration a 1-D Allen-Cahn
equation with Neumann boundary conditions. Numerical examples are given and
perspectives for the application of this approach to electrochemical systems
are discussed.


title: Note on Poincar\'e type K\"ahler metrics and Futaki characters

abstract:
  A Poincar\'e type K\"ahler metric on the complement X\D of a simple normal
crossing divisor D, in a compact K\"ahler manifold X, is a K\"ahler metric on
X\D with cusp singularity along D. We relate the Futaki character for
holomorphic vector fields parallel to the divisor, defined for any fixed
Poincar\'e type K\"ahler class, to the classical Futaki character for the
relative smooth class. As an application we express a numerical obstruction to
the existence of extremal Poincar\'e type K\"ahler metrics, in terms of mean
scalar curvatures and Futaki characters.


title: Twin paradox with macroscopic clocks in superconducting circuits

abstract:
  We propose an implementation of a twin paradox scenario in superconducting
circuits, with velocities as large as a few percent of the speed of light.
Ultrafast modulation of the boundary conditions for the electromagnetic field
in a microwave cavity simulates a clock moving at relativistic speeds. Since
our cavity has a finite length, the setup allows us to investigate the role of
clock size as well as interesting quantum effects on time dilation. In
particular, our theoretical results show that the time dilation increases for
larger cavity lengths and is shifted due to quantum particle creation.


title:
Boundedness of Functions on Product Spaces by Sums of Functions on the
  Factors

abstract:
  We investigate sufficient conditions for real-valued functions on product
spaces to be bounded from above by sums or products of functions which depend
only on points in the respective factors.


title: System Analysis And Design For Multimedia Retrieval Systems

abstract:
  Due to the extensive use of information technology and the recent
developments in multimedia systems, the amount of multimedia data available to
users has increased exponentially. Video is an example of multimedia data as it
contains several kinds of data such as text, image, meta-data, visual and
audio. Content based video retrieval is an approach for facilitating the
searching and browsing of large multimedia collections over WWW. In order to
create an effective video retrieval system, visual perception must be taken
into account. We conjectured that a technique which employs multiple features
for indexing and retrieval would be more effective in the discrimination and
search tasks of videos. In order to validate this, content based indexing and
retrieval systems were implemented using color histogram, Texture feature
(GLCM), edge density and motion..


title: General Standby Component Allocation in Series and Parallel Systems

abstract:
  Optimum lifetime of a series (resp. parallel) system with general standby
component(s) always depends on allocation strategy of standby component(s) into
the system. Here, we discuss three different models of one or more standby
compo- nents. In each model, we compare different series (resp. parallel)
systems (which are formed through different allocation strategies of standby
component(s)) with respect to the usual stochastic and the stochastic
precedence orders.


title: Computing nullity and kernel vectors using NF-package: Counterexamples

abstract:
  A computational technique for calculating nullity vectors and kernel vectors,
using the new Finsler package, is introduced. As an application, three
interesting counterexamples are given. The first counterexample shows that the
two distributions $\mathrm{Ker}_R$ and $\N_R$ do not coincide. The second shows
that the nullity distribution $\N_{P^\circ}$ is not completely integrable. The
third shows that the nullity distribution $\N_\mathfrak{R}$ is not a
sub-distribution of the nullity distribution $\N_{R^\circ}$.


title: Minimal zeros of copositive matrices

abstract:
  Let $A$ be an element of the copositive cone ${\cal C}_n$. A zero $u$ of $A$
is a nonzero nonnegative vector such that $u^TAu = 0$. The support of $u$ is
the index set $\mbox{supp}u \subset \{1,\dots,n\}$ corresponding to the
positive entries of $u$. A zero $u$ of $A$ is called minimal if there does not
exist another zero $v$ of $A$ such that its support $\mbox{supp}v$ is a strict
subset of $\mbox{supp}u$. We investigate the properties of minimal zeros of
copositive matrices and their supports. Special attention is devoted to
copositive matrices which are irreducible with respect to the cone $S_+(n)$ of
positive semi-definite matrices, i.e., matrices which cannot be written as a
sum of a copositive and a nonzero positive semi-definite matrix. We give a
necessary and sufficient condition for irreducibility of a matrix $A$ with
respect to $S_+(n)$ in terms of its minimal zeros. A similar condition is given
for the irreducibility with respect to the cone ${\cal N}_n$ of entry-wise
nonnegative matrices. For $n = 5$ matrices which are irreducible with respect
to both $S_+(5)$ and ${\cal N}_5$ are extremal. For $n = 6$ a list of candidate
combinations of supports of minimal zeros which an exceptional extremal matrix
can have is provided.


title: Magnetic quantum ratchet effect in Si-MOSFETs

abstract:
  We report on the observation of magnetic quantum ratchet effect in
metal-oxide-semiconductor field-effect-transistors on silicon surface
(Si-MOSFETs). We show that the excitation of an unbiased transistor by ac
electric field of terahertz radiation at normal incidence leads to a direct
electric current between the source and drain contacts if the transistor is
subjected to an in-plane magnetic field. The current rises linearly with the
magnetic field strength and quadratically with the ac electric field amplitude.
It depends on the polarization state of the ac field and can be induced by both
linearly and circularly polarized radiation. We present the quasi-classical and
quantum theories of the observed effect and show that the current originates
from the Lorentz force acting upon carriers in asymmetric inversion channels of
the transistors.


title:
A new measurement method of electrode gains for orthogonal symmetric
  type beam position monitor

abstract:
  The new beam position monitor (BPM) system of the injector at the upgrade
project of Hefei Light Source (HLS II) has 19 stripline beam position monitors.
Most consist of four orthogonal symmetric stripline electrodes. The differences
in electronic gain and mismachining tolerance can cause the change of the beam
response of the BPM electrodes. This variation will couple the two measured
horizontal positions in order to bring the measuring error. To alleviate this
effect, a new technique to measure the relative response of the four electrodes
has been developed. It is irrelevant to the beam charge and the related
coefficient can be theoretical calculated. The effect of electrodes coupling on
this technique is analyzed. The calibration data is used to fit the gain for
all 19 injector beam position monitors. The results show the standard deviation
of the distribution of measured gains is about 5%.


title: Audit Maturity Model

abstract:
  Today it is crucial for organizations to pay even greater attention on
quality management as the importance of this function in achieving ultimate
business objectives is increasingly becoming clearer. Importance of the Quality
Management Function in achieving basic need by ensuring compliance with
Capability Maturity Model Integrated or International Organization for
Standardization is a basic demand from business nowadays. However, Quality
Management Function and its processes need to be made much more mature to
prevent delivery outages and to achieve business excellence through their
review and auditing capability. Many organizations now face challenges in
determining the maturity of the Quality Management group along with the service
offered by them and the right way to elevate the maturity of the same. The
objective of this whitepaper is to propose a new model, the Audit Maturity
Model which will provide organizations with a measure of their maturity in
quality management in the perspective of auditing, along with recommendations
for preventing delivery outage, and identifying risk to achieve business
excellence. This will enable organizations to assess Quality Management
maturity higher than basic hygiene and will also help them to identify gaps and
to take corrective actions for achieving higher maturity levels. Hence the
objective is to envisage a new auditing model as a part of organisation quality
management function which can be a guide for them to achieve higher level of
maturity and ultimately help to achieve delivery and business excellence.


title: Chromatic Number Via Turan Number

abstract:
  A Kneser representation KG(H) for a graph G is a bijective assignment of
hyperedges of a hypergraph H to the vertices of G such that two vertices of G
are adjacent if and only if the corresponding hyperedges are disjoint. In this
paper, we introduce a colored version of the Turan number and use that to
determine the chromatic number of some families of graphs in terms of the
generalized Turan number of graphs. In particular, we determine the chromatic
number of every Kneser multigraph KG(H), where the vertex set of H is the edge
set of a multigraph G such that the multiplicity of each edge is greater than 1
and a hyperedge in H corresponds to a subgraph of G isomorphic to some graph in
a fixed prescribed family of simple graphs.


title: Progress on soft gluon exponentiation and long-distance singularities

abstract:
  I review the recent progress in studying long-distance singularities in
gauge-theory scattering amplitudes in terms of Wilson lines. The non-Abelian
exponentiation theorem, which has been recently generalised to the case of
multi-leg amplitudes, states that diagrams exponentiate such that the colour
factors in the exponent are fully connected. After a brief review of the
diagrammatic approach to soft gluon exponentiation, I sketch the method we used
to prove the theorem and illustrate how connected colour factors emerge in the
exponent in webs that are formed by sets of multiple-gluon-exchange diagrams.
In the second part of the talk I report on recent progress in evaluating the
corresponding integrals, where a major simplification is achieved upon
formulating the calculation in terms of subtracted webs. I argue that the
contributions of all multiple-gluon-exchange diagrams to the soft anomalous
dimension take the form of products of specific polylogarithmic functions, each
depending on a single cusp angle.


title: Hadron Polarizabilities

abstract:
  Electromagnetic polarizabilities describe the response of a system to the
application of an external quasi-static electric or magnetic field. In this
article experimental and theoretical work addressing the polarizabilities of
the light hadrons is examined.


title: Cycle theory of relative correspondences

abstract:
  We establish a theory of complexes of relative correspondences. The theory
generalizes the known theory of complexes of correspondences of smooth
projective varieties. It will be applied in the sequel of this paper to the
construction of the triangulated category of motives over a base variety.


title:
Diverse forms of $\sigma$ bonding in two-dimensional Si allotropes:
  Nematic orbitals in the $MoS_2$ structure

abstract:
  The interplay of $sp^2$- and $sp^3$-type bonding defines silicon allotropes
in two- and three-dimensional forms. A novel two-dimensional phase bearing
structural resembleance to a single MoS$_2$ layer is found to possess a lower
total energy than low-buckled silicene and to be stable in terms of its phonon
dispersion relations. A new set of cigar-shaped, nematic orbitals originating
from the Si $sp^2$ orbitals realizes bonding with a 6-fold coordination of the
inner Si atoms of the layer. The identification of these nematic orbitals
advocates diverse Si bonding configurations different from those of C atoms.


title:
Constant Mean Curvature Foliations of $3$-Dimensional Twisted Product
  Spacetimes

abstract:
  For $2+1$ spacetime dimensions, we derive sufficient conditions for the
twisting function in a twisted product spacetime, such that there is a global
foliation by spacelike CMC surfaces.


title: Quasi DG categories and mixed motivic sheaves

abstract:
  We introduce the notion of a quasi DG category, generalizing that of a DG
category. To a quasi DG category satisfying certain additional conditions, we
associate another quasi DG category, the quasi DG category of $C$-diagrams. We
then show the homotopy category of the quasi DG category of $C$-diagrams has
the structure of a triangulated category. This procedure is then applied to
produce a triangulated category of mixed motives over a base variety.


title:
Low regularity local well-posedness for the Chern-Simons-Higgs system in
  temporal gauge

abstract:
  The Cauchy problem for the Chern-Simons-Higgs system in the (2+1)-dimensional
Minkowski space in temporal gauge is locally well-posed for low regularity
initial data improving a result of Huh. The proof uses the bilinear space-time
estimates in wave-Sobolev spaces by d'Ancona, Foschi and Selberg and takes
advantage of a null condition.


title:
Effects of homogenous broadening on the Rabi splitting in micropillar
  cavities with strong light-matter interaction

abstract:
  We solve the low-energy part of the spectrum of a model that describes a
cavity mode strongly coupled to an exciton, and both modes coupled to continua
of bosonic excitations which give rise to homogeneous broadenig. The spectral
density of the cavity modes in the low-energy manifold agrees with measured
photoluminiscense spectra. We suggest fitting these spectra with a sum of two
asymmetric Lorentzians.


title:
Spatial distribution of Spontaneous Parametric Down-Converted Photons
  for higher order Optical Vortices

abstract:
  We make a source of entangled photons (SEP) using spontaneous parametric
down-conversion (SPDC) in a non-linear crystal and study the spatial
distribution of photon pairs obtained through the down-conversion of different
modes of light including higher order vortices. We observe that for the
Gaussian pump, the thickness of the SPDC ring varies linearly with the radius
of pump beam. However, in case of vortex carrying beams, two concentric SPDC
rings are formed for beams above a critical radius. The full width at half
maximum (FWHM) of SPDC rings increase with increase in the order of optical
vortex beams. The presence of a critical beam width for the vortices as well as
the observed FWHM of the SPDC rings are supported with our numerical results.


title:
About transmission of thermal light through the surface of a body into
  the vacuum

abstract:
  The problem of the change of photon distribution of thermal light passing
through the body surface into the vacuum is discussed. It is shown that the
usual assumption that each photon passes through the boundary totally
independent of others contradicts the expression for the fluctuation of thermal
light found by A. Einstein.


title: Transformation Double Categories Associated to 2-Group Actions

abstract:
  Transformation groupoids associated to group actions capture the interplay
between global and local symmetries of structures described in set-theoretic
terms. This paper examines the analogous situation for structures described in
category-theoretic terms, where symmetry is expressed as the action of a
2-group G (equivalently, a categorical group) on a category C. It describes the
construction of a transformation groupoid in diagrammatic terms, and considers
this construction internal to Cat, the category of categories. The result is a
double category C//G which describes the local symmetries of C. We define this
and describe some of its structure, with the adjoint action of G on itself as a
guiding example.


title: Floer trajectories and stabilizing divisors

abstract:
  We incorporate pearly Floer trajectories into the transversality scheme for
pseudoholomorphic maps introduced by Cieliebak-Mohnke. By choosing generic
domain-dependent almost complex structures we obtain zero and one-dimensional
moduli spaces with the structure of cell complexes with rational fundamental
classes. This gives a definition of Floer cohomology over Novikov rings via
stabilizing divisors for compact symplectic manifolds with rational symplectic
classes and Lagrangians that are fixed point sets of anti-symplectic
involutions satisfying certain Maslov index conditions, in particular,
Hamiltonian Floer cohomology.


title:
The two-body hadronic decays of $B_c$ meson in the perturbative QCD
  approach: A short review

abstract:
  Along with the running of Large Hadron Collider (LHC) located at CERN in
November 2009, a large number of data samples of $B_c$ meson have been
collected and some hadronic $B_c$ decay modes have been measured by the LHC
experiments. In view of the special and important roles of $B_c$ meson decays
playing in the heavy flavor sector, we here give a short review on the status
of two body hadronic decays $B_c \to M_1 M_2$ at both experimental and
theoretical aspects. For the theoretical progresses, specifically, we will show
lots of theoretical studies on two body hadronic $B_c$ decays involving
pseudoscalar, vector, scalar, axial-vector, even tensor meson(s) in the final
states by employing the perturbative QCD (pQCD) factorization approach. We will
present a general analysis about the two-body hadronic decays of the heavy
$B_c$ meson and also provide some expectations for the future developments.


title: The Higgs data and the Decoupling Limit

abstract:
  The Higgs data analyzed by the ATLAS and CMS Collaborations suggest that the
scalar state discovered in 2012 is a Standard Model (SM)--like Higgs boson.
Nevertheless, there is still significant room for Higgs physics beyond the
Standard Model. Many approaches to electroweak symmetry breaking possess a
decoupling limit in which the properties of the lightest CP-even Higgs scalar
approach those of the SM Higgs boson. In some cases, an apparent SM-like Higgs
signal can also arise in a regime that may not be governed by the decoupling
limit. One such scenario can be realized if the observed Higgs signal is a
result of two unresolved nearly-mass-degenerate scalar states. The general
two-Higgs doublet model provides a useful framework for studying the decoupling
limit and possible departures from SM-like Higgs behavior. The implications for
current and future Higgs data are briefly considered.


title:
The Minimum Number of Rotations About Two Axes for Constructing an
  Arbitrary Fixed Rotation

abstract:
  For any pair of three-dimensional real unit vectors $\hat{m}$ and $\hat{n}$
with $|\hat{m}^{\rm T} \hat{n}| < 1$ and any rotation $U$, let
$N_{\hat{m},\hat{n}}(U)$ denote the least value of a positive integer $k$ such
that $U$ can be decomposed into a product of $k$ rotations about either
$\hat{m}$ or $\hat{n}$. This work gives the number $N_{\hat{m},\hat{n}}(U)$ as
a function of $U$. Here a rotation means an element $D$ of the special
orthogonal group ${\rm SO}(3)$ or an element of the special unitary group ${\rm
SU}(2)$ that corresponds to $D$. Decompositions of $U$ attaining the minimum
number $N_{\hat{m},\hat{n}}(U)$ are also given explicitly.


title: Spectral and asymptotic properties of Grover walks on crystal lattice

abstract:
  We propose a twisted Szegedy walk for estimating the limit behavior of a
discrete-time quantum walk on a crystal lattice, an infinite abelian covering
graph, whose notion was introduced by [14]. First, we show that the spectrum of
the twisted Szegedy walk on the quotient graph can be expressed by mapping the
spectrum of a twisted random walk onto the unit circle. Secondly, we show that
the spatial Fourier transform of the twisted Szegedy walk on a finite graph
with appropriate parameters becomes the Grover walk on its infinite abelian
covering graph. Finally, as an application, we show that if the Betti number of
the quotient graph is strictly greater than one, then localization is ensured
with some appropriated initial state. We also compute the limit density
function for the Grover walk on $\mathbb{Z}^d$ with flip flop shift, which
implies the coexistence of linear spreading and localization. We partially
obtain the abstractive shape of the limit density function: the support is
within the $d$-dimensional sphere of radius $1/\sqrt{d}$, and $2^d$ singular
points reside on the sphere's surface.


title:
Anhamonic finite temperature effects on the Raman and Infrared spectra
  to determine the crystal structure phase III of solid molecular hydrogen

abstract:
  We present theoretical calculations of the Raman and IR spectra, as well as
electronic properties at zero and finite temperature to elucidate the crystal
structure of phase III of solid molecular hydrogen. We find that anharmonic
finite temperature are particularly important and qualitatively influences the
main conclusions. While P6$_3$/m is the most likely candidate for phase III at
the nuclear ground state, at finite temperature the C2/c structure appears to
be more suitable.

categories: cond-mat.mtrl-sci cond-mat.other cond-mat.supr-con physics.chem-ph physics.comp-ph


title:
Star-galaxy separation strategies for WISE-2MASS all-sky infrared galaxy
  catalogs

abstract:
  We combine photometric information of the WISE and 2MASS all-sky infrared
databases, and demonstrate how to produce clean and complete galaxy catalogs
for future analyses. Adding 2MASS colors to WISE photometry improves
star-galaxy separation efficiency substantially at the expense of loosing a
small fraction of the galaxies. We find that 93% of the WISE objects within
W1<15.2 mag have a 2MASS match, and that a class of supervised machine learning
algorithms, Support Vector Machines (SVM), are efficient classifiers of objects
in our multicolor data set. We constructed a training set from the SDSS
PhotoObj table with known star-galaxy separation, and determined redshift
distribution of our sample from the GAMA spectroscopic survey. Varying the
combination of photometric parameters input into our algorithm we show that W1
- J is a simple and effective star-galaxy separator, capable of producing
results comparable to the multi-dimensional SVM classification. We present a
detailed description of our star-galaxy separation methods, and characterize
the robustness of our tools in terms of contamination, completeness, and
accuracy. We explore systematics of the full sky WISE-2MASS galaxy map, such as
contamination from Moon glow. We show that the homogeneity of the full sky
galaxy map is improved by an additional J<16.5 mag flux limit. The all-sky
galaxy catalog we present in this paper covers 21,200 sq. degrees with dusty
regions masked out, and has an estimated stellar contamination of 1.2% and
completeness of 70.1% among 2.4 million galaxies with $z_{med}= 0.14$.
WISE-2MASS galaxy maps with well controlled stellar contamination will be
useful for spatial statistical analyses, including cross correlations with
other cosmological random fields, such as the Cosmic Microwave Background. The
same techniques also yield a statistically controlled sample of stars as well.


title: Large Aperiodic Semigroups

abstract:
  The syntactic complexity of a regular language is the size of its syntactic
semigroup. This semigroup is isomorphic to the transition semigroup of the
minimal deterministic finite automaton accepting the language, that is, to the
semigroup generated by transformations induced by non-empty words on the set of
states of the automaton. In this paper we search for the largest syntactic
semigroup of a star-free language having $n$ left quotients; equivalently, we
look for the largest transition semigroup of an aperiodic finite automaton with
$n$ states.
  We introduce two new aperiodic transition semigroups. The first is generated
by transformations that change only one state; we call such transformations and
resulting semigroups unitary. In particular, we study complete unitary
semigroups which have a special structure, and we show that each maximal
unitary semigroup is complete. For $n \ge 4$ there exists a complete unitary
semigroup that is larger than any aperiodic semigroup known to date.
  We then present even larger aperiodic semigroups, generated by
transformations that map a non-empty subset of states to a single state; we
call such transformations and semigroups semiconstant. In particular, we
examine semiconstant tree semigroups which have a structure based on full
binary trees. The semiconstant tree semigroups are at present the best
candidates for largest aperiodic semigroups.
  We also prove that $2^n-1$ is an upper bound on the state complexity of
reversal of star-free languages, and resolve an open problem about a special
case of state complexity of concatenation of star-free languages.


title:
The p-H symmetry breaking in dissociative ionization of H2 due to the
  molecular ion interaction with the ejected electron

abstract:
  We propose a novel mechanism of electron localization and molecular symmetry
breaking in dissociative photoionization of the H$_2$ molecule. The Coulomb
field of the ejected electron can induce transition of the remaining H$_2^+$
ion from the gerade $^2\Sigma_g^1(1s\sigma_g)$ to the ungerade
$^2\Sigma_u^1(2p\sigma_u)$ electronic state when the nuclei in a bound
vibrational state are near the outer turning point. The superposition of this
process with a direct transition to vibrational continuum should produce a
non-gerade ionic state which results in observed asymmetry in the $p$-H
ejection relative to the electron ejection direction at a small kinetic energy
release.


title:
Speeding-Up Convergence via Sequential Subspace Optimization: Current
  State and Future Directions

abstract:
  This is an overview paper written in style of research proposal. In recent
years we introduced a general framework for large-scale unconstrained
optimization -- Sequential Subspace Optimization (SESOP) and demonstrated its
usefulness for sparsity-based signal/image denoising, deconvolution,
compressive sensing, computed tomography, diffraction imaging, support vector
machines. We explored its combination with Parallel Coordinate Descent and
Separable Surrogate Function methods, obtaining state of the art results in
above-mentioned areas. There are several methods, that are faster than plain
SESOP under specific conditions: Trust region Newton method - for problems with
easily invertible Hessian matrix; Truncated Newton method - when fast
multiplication by Hessian is available; Stochastic optimization methods - for
problems with large stochastic-type data; Multigrid methods - for problems with
nested multilevel structure. Each of these methods can be further improved by
merge with SESOP. One can also accelerate Augmented Lagrangian method for
constrained optimization problems and Alternating Direction Method of
Multipliers for problems with separable objective function and non-separable
constraints.


title: Stochastic Desertification

abstract:
  The process of desertification is usually modeled as a first order
transition, where a change of an external parameter (e.g. precipitation) leads
to a catastrophic bifurcation followed by an ecological regime shift. However,
vegetation elements like shrubs and trees undergo a stochastic birth-death
process with an absorbing state; such a process supports a second order
continuous transition with no hysteresis. We present a numerical study of a
minimal model that supports bistability and catastrophic shift on spatial
domain with demographic noise and an absorbing state. When the external
parameter varies adiabatically the transition is continuous and the front
velocity renormalizes to zero at the extinction transition. Below the
transition one may identify three modes of desertification: accumulation of
local catastrophes, desert invasion and global collapse. A catastrophic regime
shift occurs as a dynamical hysteresis, when the pace of environmental
variations is too fast. We present some empirical evidence, suggesting that the
mid-holocene desertification of the Sahara was, indeed, continuous.


title: Mass and radius formulas for low-mass neutron stars

abstract:
  Neutron stars, produced at the death of massive stars, are often regarded as
giant neutron-rich nuclei. This picture is especially relevant for low-mass
(below about solar mass) neutron stars, where non-nucleonic components are not
expected to occur. Due to the saturation property of nucleonic matter, leading
to the celebrated liquid-drop picture of atomic nuclei, empirical nuclear
masses and radii can be approximately expressed as function of atomic mass
number. It is, however, not straightforward to express masses and radii of
neutron stars even in the low-mass range where the structure is determined by a
balance between the pressure of neutron-rich nucleonic matter and the gravity.
Such expressions would be of great use given possible simultaneous mass and
radius measurements. Here we successfully construct theoretical formulas for
the masses and radii of low-mass neutron stars from various models that are
consistent with empirical masses and radii of stable nuclei. In this process,
we discover a new equation-of-state parameter that characterizes the structure
of low-mass neutron stars. This parameter, which plays a key role in connecting
the mass-radius relation of the laboratory nuclei to that of the celestial
objects, could be constrained from future observations of low-mass neutron
stars.


title: Categories of diagrams with irreversible moves

abstract:
  We work with a generalization of knot theory, in which one diagram is
reachable from another via a finite sequence of moves if a fixed condition,
regarding the existence of certain morphisms in an associated category, is
satisfied for every move of the sequence. This conditional setting leads to a
possibility of irreversible moves, terminal states, and to using functors more
general than the ones used as knot invariants. Our main focus is the category
of diagrams with binary relations on the set of arcs, indicating which arc can
move over another arc. We define homology of binary relations, and merge it
with quandle homology, to obtain the homology for partial quandles with binary
relations. This last homology can be used to analyze link diagrams with binary
relations on the set of components.


title: Fast Algorithm for Partial Covers in Words

abstract:
  A factor $u$ of a word $w$ is a cover of $w$ if every position in $w$ lies
within some occurrence of $u$ in $w$. A word $w$ covered by $u$ thus
generalizes the idea of a repetition, that is, a word composed of exact
concatenations of $u$. In this article we introduce a new notion of
$\alpha$-partial cover, which can be viewed as a relaxed variant of cover, that
is, a factor covering at least $\alpha$ positions in $w$. We develop a data
structure of $O(n)$ size (where $n=|w|$) that can be constructed in $O(n\log
n)$ time which we apply to compute all shortest $\alpha$-partial covers for a
given $\alpha$. We also employ it for an $O(n\log n)$-time algorithm computing
a shortest $\alpha$-partial cover for each $\alpha=1,2,\ldots,n$.


title: Periodic thermodynamics of isolated systems

abstract:
  The nature of the behaviour of an isolated many-body quantum system
periodically driven in time has been an open question since the beginning of
quantum mechanics. After an initial transient, such a system is known to
synchronize with the driving; in contrast to the non-driven case, no
fundamental principle has been proposed for constructing the resulting
non-equilibrium state. Here, we analytically show that, for a class of
integrable systems, the relevant ensemble is constructed by maximizing an
appropriately defined entropy subject to constraints, which we explicitly
identify. This result constitutes a generalisation of the concepts of
equilibrium statistical mechanics to a class of far-from-equilibrium-systems,
up to now mainly accessible using ad-hoc methods.


title:
Orthogonal invariant sets of the diffusion tensor and the development of
  a curvilinear set suitable for low-anisotropy tissues

abstract:
  We develop a curvilinear invariant set of the diffusion tensor which may be
applied to Diffusion Tensor Imaging measurements on tissues and porous media.
This new set is an alternative to the more common invariants such as fractional
anisotropy and the diffusion mode. The alternative invariant set possesses a
different structure to the other known invariant sets; the second and third
members of the curvilinear set measure the degree of orthotropy and
oblateness/prolateness, respectively. The proposed advantage of these
invariants is that they may work well in situations of low diffusion anisotropy
and isotropy, as is often observed in tissues such as cartilage.
  We also explore the other orthogonal invariant sets in terms of their
geometry in relation to eigenvalue space; a cylindrical set, a spherical set
(including fractional anisotropy and the mode), and a log-Euclidean set. These
three sets have a common structure. The first invariant measures the magnitude
of the diffusion, the second and third invariants capture aspects of the
anisotropy; the magnitude of the anisotropy and the shape of the diffusion
ellipsoid (the manner in which the anisotropy is realised). We also show a
simple method to prove the orthogonality of the invariants within a set.


title: Medical Image Fusion: A survey of the state of the art

abstract:
  Medical image fusion is the process of registering and combining multiple
images from single or multiple imaging modalities to improve the imaging
quality and reduce randomness and redundancy in order to increase the clinical
applicability of medical images for diagnosis and assessment of medical
problems. Multi-modal medical image fusion algorithms and devices have shown
notable achievements in improving clinical accuracy of decisions based on
medical images. This review article provides a factual listing of methods and
summarizes the broad scientific challenges faced in the field of medical image
fusion. We characterize the medical image fusion research based on (1) the
widely used image fusion methods, (2) imaging modalities, and (3) imaging of
organs that are under study. This review concludes that even though there
exists several open ended technological and scientific challenges, the fusion
of medical images has proved to be useful for advancing the clinical
reliability of using medical imaging for medical diagnostics and analysis, and
is a scientific discipline that has the potential to significantly grow in the
coming years.


title: Causality Violation and Nonlinear Quantum Mechanics

abstract:
  It is currently unknown whether the laws of physics permit time travel into
the past. While general relativity indicates the theoretical possibility of
causality violation, it is now widely accepted that a theory of quantum gravity
must play an essential role in such cases. As a striking example, the logical
paradoxes usually associated with causality violation can be resolved by
quantum effects. We ask whether the explicit construction of a theory that
allows causality violation might in turn teach us something about quantum
gravity. Taking the toy model of Deutsch as a starting point, in Part I we
argue that, despite being a nonlinear modification of quantum mechanics, the
model does not imply superluminal signalling and its predictions can be
operationally verified by experimenters within an appropriate ontological
setting. In Part II we show that the model can be directly applied to scalar
quantum fields, provided the fields are sent back in time by an amount much
larger than the coherence time of the wavepackets. We propose a generalisation
of the model that lifts this constraint and recovers the predictions of
standard quantum field theory when the size of the temporal jump is much
smaller than the coherence time of the wavepackets. Finally, we discuss an
extension of the model to ordinary gravitational time dilation. The resulting
model generalises and extends earlier work on the topic and can be tested
experimentally using current technology.


title: Efficient inference and simulation for elliptical Pareto processes

abstract:
  Recent advances in extreme value theory have established $\ell$-Pareto
processes as the natural limits for extreme events defined in terms of
exceedances of a risk functional. Here we provide methods for the practical
modelling of data based on a tractable yet flexible dependence model. We
introduce the class of elliptical $\ell$-Pareto processes, which arise as the
limit of threshold exceedances of certain elliptical processes characterized by
a correlation function and a shape parameter. An efficient inference method
based on maximizing a full likelihood with partial censoring is developed.
Novel procedures for exact conditional and unconditional simulation are
proposed. These ideas are illustrated using precipitation extremes in
Switzerland.


title:
Extremal Hypergraphs for Ryser's Conjecture: Connectedness of Line
  Graphs of Bipartite Graphs

abstract:
  In this paper we consider a natural extremal graph theoretic problem of
topological sort, concerning the minimization of the (topological)
connectedness of the independence complex of graphs in terms of its dimension.
We observe that the lower bound $\frac{\dim(\mathcal{I}(G))}{2} - 2$ on the
connectedness of the independence complex $\mathcal{I}(G)$ of line graphs of
bipartite graphs $G$ is tight. In our main theorem we characterize the extremal
examples. Our proof of this characterization is based on topological machinery.
  Our motivation for studying this problem comes from a classical conjecture of
Ryser. Ryser's Conjecture states that any $r$-partite $r$-uniform hypergraph
has a vertex cover of size at most $(r - 1)$-times the size of the largest
matching. For $r = 2$, the conjecture is simply K\"onig's Theorem. It has also
been proven for $r = 3$ by Aharoni using a beautiful topological argument. In a
separate paper we characterize the extremal examples for the $3$-uniform case
of Ryser's Conjecture (i.e., Aharoni's Theorem), and in particular resolve an
old conjecture of Lov\'asz for the case of Ryser-extremal $3$-graphs.
  Our main result in this paper will provide us with valuable structural
information for that characterization. Its proof is based on the observation
that link graphs of Ryser-extremal $3$-uniform hypergraphs are exactly the
bipartite graphs we study here.


title:
Interface induced manipulation of perpendicular exchange bias in
  Pt/Co/(Pt, Cr)/CoO thin films

abstract:
  Perpendicular exchange bias has been manipulated by changing ferromagnetic
film thickness and spacer layer in Pt/Co/(Pt, Cr)/CoO thin films. The exchange
bias characteristics, blocking temperature, magnetization of thin films
strongly depend on the spacer layer (Pt, Cr) between ferromagnetic and
antiferromagnetic layers. While Pt/Co/Pt/CoO thin films show perpendicular
exchange bias, Pt/Co/Cr/CoO has easy magnetization axis in the film plane. We
have also observed very small hysteretic behavior from the hard axis
magnetization curve of Pt/Co/Cr/CoO film. This can be attributed to
misalignment of the sample or small perpendicular contribution from Pt/Co
bottom interface. We have also investigated the temperature and spacer layer
dependent exchange bias properties of the samples by VSM magnetometry. We
observed higher HEB and HC for the thicker Co layer in the Pt/Co/Pt/CoO sample.
In addition, onset of exchange bias effect starts at much lower temperatures
for Pt/Co/Cr/CoO thin film. This clearly shows that Cr spacer layer not only
removes the perpendicular exchange bias, but also reduces the exchange
interaction between Co and CoO and thus lowers the blocking temperature.


title: Extremal Hypergraphs for Ryser's Conjecture: Home-Base Hypergraphs

abstract:
  Ryser's Conjecture states that any $r$-partite $r$-uniform hypergraph has a
vertex cover of size at most $r - 1$ times the size of the largest matching.
For $r = 2$, the conjecture is simply K\"onig's Theorem and every bipartite
graph is a witness for its tightness. The conjecture has also been proven for
$r = 3$ by Aharoni using topological methods, but the proof does not give
information on the extremal $3$-uniform hypergraphs. Our goal in this paper is
to characterize those hypergraphs which are tight for Aharoni's Theorem.
  Our proof of this characterization is also based on topological machinery,
particularly utilizing results on the (topological) connectedness of the
independence complex of the line graph of the link graphs of $3$-uniform
Ryser-extremal hypergraphs, developed in a separate paper. The current paper
contains the second, structural hypergraph-theoretic part of the argument,
where we use the information on the line graph of the link graphs to nail down
the elements of a structure we call \emph{home-base hypergraph}. While there is
a single minimal home-base hypergraph with matching number $k$ for every
positive integer $k \in \mathbb{N}$, home-base hypergraphs with matching number
$k$ are far from being unique. There are infinitely many of them and each of
them is composed of $k$ copies of two different kinds of basic structures,
whose hyperedges can intersect in various restricted, but intricate ways.
  Our characterization also proves an old and wide open strengthening of
Ryser's Conjecture, due to Lov\'asz, for the $3$-uniform extremal case, that
is, for hypergraphs with $\tau = 2 \nu$.


title: Dissociation of Quarkonium in a Complex Potential

abstract:
  We have studied the quasi-free dissociation of quarkonia through a complex
potential which is obtained by correcting both the perturbative and
nonperturbative terms of the $Q \bar Q$ potential at T=0 through the dielectric
function in real-time formalism. The presence of confining nonperturbative term
even above the transition temperature makes the real-part of the potential more
stronger and thus makes the quarkonia more bound and also enhances the
(magnitude) imaginary-part which, in turn contributes more to the thermal
width, compared to the medium-contribution of the perturbative term alone.
These cumulative observations result the quarkonia to dissociate at higher
temperatures. Finally we extend our calculation to a medium, exhibiting local
momentum anisotropy, by calculating the leading anisotropic corrections to the
propagators in Keldysh representation. The presence of anisotropy makes the
real-part of the potential stronger but the imaginary-part is weakened
slightly. However, since the medium corrections to the imaginary-part is a
small perturbation to the vacuum part, overall the anisotropy makes the
dissociation temperatures higher, compared to isotropic medium.


title:
Normal zeta functions of the Heisenberg groups over number rings I - the
  unramified case

abstract:
  Let $K$ be a number field with ring of integers $\mathcal{O}_K$. We compute
explicitly the local factors of the normal zeta functions of the Heisenberg
groups $H(\mathcal{O}_K)$ that are indexed by rational primes which are
unramified in $K$. We show that these local zeta functions satisfy functional
equations upon the inversion of the prime.


title: Separating a Voronoi Diagram via Local Search

abstract:
  Given a set $\mathsf{P}$ of $n$ points in $\mathbb{R}^d$, we show how to
insert a set $\mathsf{X}$ of $O( n^{1-1/d} )$ additional points, such that
$\mathsf{P}$ can be broken into two sets $\mathsf{P}_1$ and $\mathsf{P}_2$, of
roughly equal size, such that in the Voronoi diagram $\mathcal{V}( \mathsf{P}
\cup \mathsf{X} )$, the cells of $\mathsf{P}_1$ do not touch the cells of
$\mathsf{P}_2$; that is, $\mathsf{X}$ separates $\mathsf{P}_1$ from
$\mathsf{P}_2$ in the Voronoi diagram.
  Given such a partition $(\mathsf{P}_1,\mathsf{P}_2)$ of $\mathsf{P}$, we
present approximation algorithms to compute the minimum size separator
realizing this partition.
  Finally, we present a simple local search algorithm that is a PTAS for
geometric hitting set of fat objects (which can also be used to approximate the
optimal Voronoi partition).


title: Multiple photon detection and the localization of light energy

abstract:
  It is shown that probabilities of photon detection can be found on the basis
of consideration of the phase space sells filling for an ideal photon gas,
which led Bose to the derivation of the Planks law. These probabilities are
directly connected to photon localization properties consistent with the
entropy of a dilute photon gas found by Einstein.


title:
A clock containing a massive object in a superposition of states; what
  makes Penrosian wavefunction collapse tick?

abstract:
  Penrose has been advocating the view that the collapse of the wave function
is rooted in the incompatibility between general relativity and quantum
mechanics. On the basis of conceptual analysis, he arrived at an estimate for
the collapse time. To better understand his estimate, in this paper we present
a thought experiment, which singles out the role of time-dilations in massive
superpositions. First we investigate the behavior of a hypothetical clock
containing a component which can be in a superposition of states. The clock
contains a massive object, whose only purpose is to introduce a curvature of
space time into the problem. We find that a state of this massive object with a
smaller radius, but with the same mass, experiences a larger time dilation.
Considering a coherent superposition of the large and small object, introduces
an ambiguity in the definition of a common time for both states. We assert that
this time ambiguity can be thought to affect the time evolution of a state in
different ways and that the relative phase difference between these different
interpretations can be calculated. We postulate that the wave function collapse
will occur when this phase difference becomes of order unity. An absolute
energy scale enters this equation and we recover Penrose's estimate for the
collapse time by equating the absolute energy scale to the rest mass of the
object.


title:
Automorphism tower problem and semigroup of endomorphisms for free
  Burnside groups

abstract:
  We have proved that the group of all inner automorphisms of the free Burnside
group $B(m,n)$ is the unique normal subgroup in $Aut(B(m,n))$ among all its
subgroups, which are isomorphic to free Burnside group $B(s,n)$ of some rank
$s$ for all odd $n\ge1003$ and $m>1$. It follows that the group of
automorphisms $Aut(B(m,n))$ of the free Burnside group $B(m,n)$ is complete for
odd $n\ge1003$, that is it has a trivial center and any automorphism of
$Aut(B(m,n))$ is inner. Thus, for groups $B(m,n)$ is solved the automorphism
tower problem and is showed that it is as short as the automorphism tower of
the absolutely free groups. Moreover, proved that every automorphism of
$End(B(m,n))$ is a conjugation by an element of $Aut(B(m,n))$.


title: Scaling analysis of negative differential thermal resistance

abstract:
  Negative differential thermal resistance (NDTR) can be generated for any
one-dimensional heat flow with a temperature-dependent thermal conductivity. In
a system-independent scaling analysis, the general condition for the occurrence
of NDTR is found to be an inequality with three scaling exponents:
$n_{1}n_{2}<-(1+n_{3})$, where $n_{1}\in(-\infty,+\infty)$ describes a
particular way of varying the temperature difference, and $n_{2}$ and $n_{3}$
describe, respectively, the dependence of the thermal conductivity on an
average temperature and on the temperature difference. For cases with a
temperature-dependent thermal conductivity, i.e. $n_{2}\neq0$, NDTR can
\emph{always} be generated with a suitable choice of $n_{1}$ such that this
inequality is satisfied. The results explain the illusory absence of a NDTR
regime in certain lattices and predict new ways of generating NDTR, where such
predictions have been verified numerically. The analysis will provide insights
for a designing of thermal devices, and for a manipulation of heat flow in
experimental systems, such as nanotubes.


title: Combinatorial duality of Hilbert schemes of points in the affine plane

abstract:
  The Hilbert scheme of $n$ points in the affine plane contains the open
subscheme parametrizing $n$ distinct points in the affine plane, and the closed
subscheme parametrizing ideals of codimension $n$ supported at the origin of
the affine plane. Both schemes admit Bia{\l}ynicki-Birula decompositions into
moduli spaces of ideals with prescribed lexicographic Gr\"obner deformations.
We show that both decompositions are stratifications in the sense that the
closure of each stratum is a union of certain other strata. We show that the
corresponding two partial orderings on the set of of monomial ideals are dual
to each other.


title: Decision Making under Uncertainty: A Quasimetric Approach

abstract:
  We propose a new approach for solving a class of discrete decision making
problems under uncertainty with positive cost. This issue concerns multiple and
diverse fields such as engineering, economics, artificial intelligence,
cognitive science and many others. Basically, an agent has to choose a single
or series of actions from a set of options, without knowing for sure their
consequences. Schematically, two main approaches have been followed: either the
agent learns which option is the correct one to choose in a given situation by
trial and error, or the agent already has some knowledge on the possible
consequences of his decisions; this knowledge being generally expressed as a
conditional probability distribution. In the latter case, several optimal or
suboptimal methods have been proposed to exploit this uncertain knowledge in
various contexts. In this work, we propose following a different approach,
based on the geometric intuition of distance. More precisely, we define a goal
independent quasimetric structure on the state space, taking into account both
cost function and transition probability. We then compare precision and
computation time with classical approaches.


title:
Painlev\'{e}-Gullstrand-type coordinates for the five-dimensional
  Myers-Perry black hole

abstract:
  The Painleve-Gullstrand coordinates provide a convenient framework for
presenting the Schwarzschild geometry because of their flat constant-time
hypersurfaces, and the fact that they are free of coordinate singularities
outside r=0. Generalizations of Painleve-Gullstrand coordinates suitable for
the Kerr geometry have been presented by Doran and Natario. These coordinate
systems feature a time coordinate identical to the proper time of
zero-angular-momentum observers that are dropped from infinity. Here, the
methods of Doran and Natario are extended to the five-dimensional rotating
black hole found by Myers and Perry. The result is a new formulation of the
Myers-Perry metric. The properties and physical significance of these new
coordinates are discussed.


title:
On inverse scattering at high energies for the multidimensional
  relativistic Newton equation in a long range electromagnetic field

abstract:
  We define scattering data for the relativistic Newton equation in an electric
field $-\nabla V\in C^1(\R^n,\R^n)$, $n\ge 2$, and in a magnetic field $B\in
C^1(\R^n,A_n(\R))$ that decay at infinity like $r^{-\alpha-1}$ for some
$\alpha\in (0,1]$, where $A_n(\R)$ is the space of $n\times n$ antisymmetric
matrices. We provide estimates on the scattering solutions and on the
scattering data and we prove, in particular, that the scattering data at high
energies uniquely determine the short range part of $(\nabla V,B)$ up to the
knowledge of the long range tail of $(\nabla V,B)$. The Born approximation at
fixed energy of the scattering data is also considered. We then change the
definition of the scattering data to study their behavior in other asymptotic
regimes. This work generalizes [Jollivet, 2007] where a short range
electromagnetic field was considered.


title:
Short-range disorder effects on electronic transport in 2D semiconductor
  structures

abstract:
  We study theoretically the relative importance of short-range disorder in
determining the low-temperature 2D mobility in GaAs-based structures with
respect to Coulomb disorder which is known to be the dominant disorder in
semiconductor systems. We give results for unscreened and screened short-range
disorder effects on 2D mobility in quantum wells and heterostructures,
comparing with the results for Coulomb disorder and finding that the asymptotic
high-density mobility is always limited by short-range disorder which, in
general, becomes effectively stronger with increasing `carrier density' in
contrast to Coulomb disorder. We also predict an intriguing re-entrant
metal-insulator transition at very high carrier densities in Si-MOSFETs driven
by the short-range disorder associated with surface roughness scattering.


title:
Measurements of mechanical thermal noise and energy dissipation in
  optical dielectric coatings

abstract:
  In recent years an increasing number of devices and experiments are shown to
be limited by mechanical thermal noise. In particular sub-Hertz laser frequency
stabilization and gravitational wave detectors, that are able to measure
fluctuations of 1E-18 m/rtHz or less, are being limited by thermal noise in the
dielectric coatings deposited on mirrors. In this paper we present a new
measurement of thermal noise in low absorption dielectric coatings deposited on
micro-cantilevers and we compare it with the results obtained from the
mechanical loss measurements. The coating thermal noise is measured on the
widest range of frequencies with the highest signal to noise ratio ever
achieved. In addition we present a novel technique to deduce the coating
mechanical losses from the measurement of the mechanical quality factor which
does not rely on the knowledge of the coating and substrate Young moduli. The
dielectric coatings are deposited by ion beam sputtering. The results presented
here give a frequency independent loss angle of (4.70 $\pm$ 0.2)x1E-4 with a
Young's modulus of 118 GPa for annealed tantala from 10 Hz to 20 kHz. For
as-deposited silica, a weak frequency dependence (~ f^{-0.025}) is observed in
this frequency range, with a Young's modulus of 70 GPa and an internal damping
of (6.0 $\pm$ 0.3)x1E-4 at 16 kHz, but this value decreases by one order of
magnitude after annealing and the frequency dependence disappears.

categories: physics.ins-det astro-ph.IM cond-mat.mtrl-sci cond-mat.stat-mech physics.optics


title:
Application of Hierarchical Matrix Techniques To The Homogenization of
  Composite Materials

abstract:
  In this paper, we study numerical homogenization methods based on integral
equations. Our work is motivated by materials such as concrete, modeled as
composites structured as randomly distributed inclusions imbedded in a matrix.
We investigate two integral reformulations of the corrector problem to be
solved, namely the equivalent inclusion method based on the Lippmann-Schwinger
equation, and a method based on boundary integral equations. The fully
populated matrices obtained by the discretization of the integral operators are
successfully dealt with using the H-matrix format.


title: An Existence Result for Hierarchical Stackelberg v/s Stackelberg Games

abstract:
  In Stackelberg v/s Stackelberg games a collection of leaders compete in a
Nash game constrained by the equilibrium conditions of another Nash game
amongst the followers. The resulting equilibrium problems are plagued by the
nonuniqueness of follower equilibria and nonconvexity of leader problems
whereby the problem of providing sufficient conditions for existence of global
or even local equilibria remains largely open. Indeed available existence
statements are restrictive and model specific. In this paper, we present what
is possibly the first general existence result for equilibria for this class of
games. Importantly, we impose no single-valuedness assumption on the
equilibrium of the follower-level game. Specifically, under the assumption that
the objectives of the leaders admit a quasi-potential function, a concept we
introduce in this paper, the global and local minimizers of a suitably defined
optimization problem are shown to be the global and local equilibria of the
game. In effect existence of equilibria can be guaranteed by the solvability of
an optimization problem, which holds under mild and verifiable conditions. We
motivate quasi- potential games through an application in communication
networks.


title: Observation and control of shock waves in individual nanoplasmas

abstract:
  In a novel experiment that images the momentum distribution of individual,
isolated 100-nm-scale plasmas, we make the first experimental observation of
shock waves in nanoplasmas. We demonstrate that the introduction of a heating
pulse prior to the main laser pulse increases the intensity of the shock wave,
producing a strong burst of quasi-monochromatic ions with an energy spread of
less than 15%. Numerical hydrodynamic calculations confirm the appearance of
accelerating shock waves, and provide a mechanism for the generation and
control of these shock waves. This observation of distinct shock waves in dense
plasmas enables the control, study, and exploitation of nanoscale shock
phenomena with tabletop-scale lasers.


title: Comparison of Simulations of Convective Flows

abstract:
  We show that a single particle distribution for the D2Q13 lattice Boltzmann
scheme can simulate coupled effects involving advection and diffusion of
velocity and temperature. We consider various test cases: non-linear waves with
periodic boundary conditions, a test case with buoyancy, propagation of
transverse waves, Couette and Poiseuille flows. We test various boundary
conditions and propose to mix bounce-back and anti-bounce-back numerical
boundary conditions to take into account velocity and temperature Dirichlet
conditions. We present also first results for the de Vahl Davis heated cavity.
Our results are compared with the coupled D2Q9-D2Q5 lattice Boltzmann approach
for the Boussinesq system and with an elementary finite differences solver for
the compressible Navier-Stokes equations.


title: On the Limits of Depth Reduction at Depth 3 Over Small Finite Fields

abstract:
  Recently, Gupta et.al. [GKKS2013] proved that over Q any $n^{O(1)}$-variate
and $n$-degree polynomial in VP can also be computed by a depth three
$\Sigma\Pi\Sigma$ circuit of size $2^{O(\sqrt{n}\log^{3/2}n)}$. Over fixed-size
finite fields, Grigoriev and Karpinski proved that any $\Sigma\Pi\Sigma$
circuit that computes $Det_n$ (or $Perm_n$) must be of size $2^{\Omega(n)}$
[GK1998]. In this paper, we prove that over fixed-size finite fields, any
$\Sigma\Pi\Sigma$ circuit for computing the iterated matrix multiplication
polynomial of $n$ generic matrices of size $n\times n$, must be of size
$2^{\Omega(n\log n)}$. The importance of this result is that over fixed-size
fields there is no depth reduction technique that can be used to compute all
the $n^{O(1)}$-variate and $n$-degree polynomials in VP by depth 3 circuits of
size $2^{o(n\log n)}$. The result [GK1998] can only rule out such a possibility
for depth 3 circuits of size $2^{o(n)}$.
  We also give an example of an explicit polynomial ($NW_{n,\epsilon}(X)$) in
VNP (not known to be in VP), for which any $\Sigma\Pi\Sigma$ circuit computing
it (over fixed-size fields) must be of size $2^{\Omega(n\log n)}$. The
polynomial we consider is constructed from the combinatorial design. An
interesting feature of this result is that we get the first examples of two
polynomials (one in VP and one in VNP) such that they have provably stronger
circuit size lower bounds than Permanent in a reasonably strong model of
computation.
  Next, we prove that any depth 4
$\Sigma\Pi^{[O(\sqrt{n})]}\Sigma\Pi^{[\sqrt{n}]}$ circuit computing
$NW_{n,\epsilon}(X)$ (over any field) must be of size $2^{\Omega(\sqrt{n}\log
n)}$. To the best of our knowledge, the polynomial $NW_{n,\epsilon}(X)$ is the
first example of an explicit polynomial in VNP such that it requires
$2^{\Omega(\sqrt{n}\log n)}$ size depth four circuits, but no known matching
upper bound.


title: The DFLU flux for systems of conservation laws

abstract:
  The DFLU numerical flux was introduced in order to solve hyperbolic scalar
conservation laws with a flux function discontinuous in space. We show how this
flux can be used to solve certain class of systems of conservation laws such as
systems modeling polymer flooding in oil reservoir engineering. Furthermore,
these results are extended to the case where the flux function is discontinuous
in the space variable. Such a situation arises for example while dealing with
oil reservoirs which are heterogeneous. Numerical experiments are presented to
illustrate the efficiency of this new scheme compared to other standard schemes
like upstream mobility, Lax-Friedrichs and Force schemes.


title:
Reasoning and Improving on Software Resilience against Unanticipated
  Exceptions

abstract:
  In software, there are the errors anticipated at specification and design
time, those encountered at development and testing time, and those that happen
in production mode yet never anticipated. In this paper, we aim at reasoning on
the ability of software to correctly handle unanticipated exceptions. We
propose an algorithm, called short-circuit testing, which injects exceptions
during test suite execution so as to simulate unanticipated errors. This
algorithm collects data that is used as input for verifying two formal
exception contracts that capture two resilience properties. Our evaluation on 9
test suites, with 78% line coverage in average, analyzes 241 executed catch
blocks, shows that 101 of them expose resilience properties and that 84 can be
transformed to be more resilient.


title: Pointwise convergence of the Lloyd algorithm in higher dimension

abstract:
  We establish the pointwise convergence of the iterative Lloyd algorithm, also
known as $k$-means algorithm, when the quadratic quantization error of the
starting grid (with size $N\ge 2$) is lower than the minimal quantization error
with respect to the input distribution is lower at level $N-1$. Such a protocol
is known as the splitting method and allows for convergence even when the input
distribution has an unbounded support. We also show under very light assumption
that the resulting limiting grid still has full size $N$. These results are
obtained without continuity assumption on the input distribution. A variant of
the procedure taking advantage of the asymptotic of the optimal quantizer
radius is proposed which always guarantees the boundedness of the iterated
grids.


title:
Mathematical analysis of a discrete fracture model coupling Darcy flow
  in the matrix with Darcy-Forchheimer flow in the fracture

abstract:
  We consider a model for flow in a porous medium with a fracture in which the
flow in the fracture is governed by the Darcy-Forchheimer law while that in the
surrounding matrix is governed by Darcy's law. We give an appropriate mixed,
variational formulation and show existence and uniqueness of the solution. To
show existence we give an analogous formulation for the model in which the
Darcy-Forchheimer law is the governing equation throughout the domain. We show
existence and uniqueness of the solution and show that the solution for the
model with Darcy's law in the matrix is the weak limit of solutions of the
model with the Darcy-Forchheimer law in the entire domain when the Forchheimer
coefficient in the matrix tends toward zero.


title:
Non-Ising Character of a Ferroelectric Wall Arises from a Flexoelectric
  Effect

abstract:
  Using the classic ferroelectric BaTiO$_3$ as an example, we show that the 180
degree ferroelectric domain wall, long considered to be of Ising-type and
charge neural, contains both Bloch and Neel type polarization components, and
is thus charged. The bound charge density at the wall may reach as high as
10$^6$~10$^7$ Cm$^{-3}$. It is demonstrated that the flexoelectric effect
arising from stress inhomogeneity is responsible for the additional Bloch and
Neel polarization components. The magnitudes of these additional components are
determined by the competing depolarization and flexoelectric fields.


title:
Finite size scaling of conformal theories in the presence of a
  near-marginal operator

abstract:
  The slowly evolving gauge coupling of gauge-fermion systems near the
conformal window makes numerical investigations of these models challenging. We
consider finite size scaling and show that this often used technique leads to
inconsistent results if the leading order scaling corrections are neglected.
When the corrections are included the results become consistent not only
between different operators but even when data obtained at different gauge
couplings or with different lattice actions are combined. Our results indicate
that the SU(3) 12-fermion system is conformal with mass anomalous dimension
$\gamma_m=0.235(15)$.


title: Unitary Equivalence of Quantum Walks

abstract:
  A simple coined quantum walk in one dimension can be characterized by a
$SU(2)$ operator with three parameters which represents the coin toss. However,
different such coin toss operators lead to equivalent dynamics of the quantum
walker. In this manuscript we present the unitary equivalence classes of
quantum walks and show that all the nonequivalent quantum walks can be
distinguished by a single parameter. Moreover, we argue that the electric
quantum walks are equivalent to quantum walks with time dependent coin toss
operator.


title:
A New Hybrid Framework to Efficiently Model Lines of Sight to
  Gravitational Lenses

abstract:
  In strong gravitational lens systems, the light bending is usually dominated
by one main galaxy, but may be affected by other mass along the line of sight
(LOS). Shear and convergence can be used to approximate the contributions from
less significant perturbers (e.g. those that are projected far from the lens or
have a small mass), but higher order effects need to be included for objects
that are closer or more massive. We develop a framework for multiplane lensing
that can handle an arbitrary combination of tidal planes treated with shear and
convergence and planes treated exactly (i.e., including higher order terms).
This framework addresses all of the traditional lensing observables including
image positions, fluxes, and time delays to facilitate lens modelling that
includes the non-linear effects due to mass along the LOS. It balances accuracy
(accounting for higher-order terms when necessary) with efficiency (compressing
all other LOS effects into a set of matrices that can be calculated up front
and cached for lens modelling). We identify a generalized multiplane mass sheet
degeneracy, in which the effective shear and convergence are sums over the
lensing planes with specific, redshift-dependent weighting factors.


title:
Whittaker-Fourier coefficients of cusp forms on $\widetilde{Sp}_n$:
  reduction to a local statement

abstract:
  In a previous paper we formulated an analogue of the Ichino-Ikeda conjectures
for Whittaker-Fourier coefficients of cusp forms on quasi-split groups, as well
as the metaplectic group of arbitrary rank. In this paper we reduce the
conjecture for the metaplectic group to a local conjectural identity. We
motivate this conjecture by giving a heuristic argument for the case
$\widetilde{SL}_2$. In a subsequent paper we will prove the local identity in
the $p$-adic case.


title: UHECR Composition Models

abstract:
  In light of the increasingly heavy UHECR composition at the highest energies,
as observed by the Pierre Auger Observatory, the implications of these results
on the actual source composition and spectra are investigated. Depending on the
maximum energy of the particles accelerated, sources producing hard spectra
and/or containing a considerably enhanced heavy component appear a necessary
requirement. Consideration is made of two archetypal models compatible with
these results. The secondary signatures expected , following the propagation of
the nuclear species from source to Earth, are determined for these two example
cases. Finally, the effect introduced by the presence of nG extragalactic
magnetic fields in collaboration with a large (80 Mpc) distance to the nearest
source is discussed.


title: Sixsoid: A new paradigm for $k$-coverage in 3D Wireless Sensor Networks

abstract:
  Coverage in 3D wireless sensor network (WSN) is always a very critical issue
to deal with. Coming up with good coverage models implies more energy efficient
networks. $K$-coverage is one model that ensures that every point in a given 3D
Field of Interest (FoI) is guaranteed to be covered by $k$ sensors. When it
comes to 3D, coming up with a deployment of sensors that gurantees $k$-coverage
becomes much more complicated than in 2D. The basic idea is to come up with a
geometrical shape that is guaranteed to be $k$-covered by taking a specific
arrangement of sensors, and then fill the FoI will non-overlapping copies of
this shape. In this work, we propose a new shape for the 3D scenario which we
call a \textbf{Devilsoid}. Prior to this work, the shape which was proposed for
coverage in 3D was the so called \textbf{Reuleaux Tetrahedron}. Our
construction is motivated from a construction that can be applied to the 2D
version of the problem \cite{MS} in which it imples better guarantees over the
\textbf{Reuleaux Triangle}. Our contribution in this paper is twofold, firstly
we show how Devilsoid gurantees more coverage volume over Reuleaux Tetrahedron,
secondly we show how Devilsoid also guarantees simpler and more pragmatic
deployment strategy for 3D wireless sensor networks. In this paper, we show the
constuction of Devilsoid, calculate its volume and discuss its effect on the
$k$-coverage in WSN.


title: Sparse Recovery with Very Sparse Compressed Counting

abstract:
  Compressed sensing (sparse signal recovery) often encounters nonnegative data
(e.g., images). Recently we developed the methodology of using (dense)
Compressed Counting for recovering nonnegative K-sparse signals. In this paper,
we adopt very sparse Compressed Counting for nonnegative signal recovery. Our
design matrix is sampled from a maximally-skewed p-stable distribution (0<p<1),
and we sparsify the design matrix so that on average (1-g)-fraction of the
entries become zero. The idea is related to very sparse stable random
projections (Li et al 2006 and Li 2007), the prior work for estimating summary
statistics of the data.
  In our theoretical analysis, we show that, when p->0, it suffices to use M=
K/(1-exp(-gK) log N measurements, so that all coordinates can be recovered in
one scan of the coordinates. If g = 1 (i.e., dense design), then M = K log N.
If g= 1/K or 2/K (i.e., very sparse design), then M = 1.58K log N or M = 1.16K
log N. This means the design matrix can be indeed very sparse at only a minor
inflation of the sample complexity.
  Interestingly, as p->1, the required number of measurements is essentially M
= 2.7K log N, provided g= 1/K. It turns out that this result is a general
worst-case bound.


title: Optimal Control with Noisy Time

abstract:
  This paper examines stochastic optimal control problems in which the state is
perfectly known, but the controller's measure of time is a stochastic process
derived from a strictly increasing L\'evy process. We provide dynamic
programming results for continuous-time finite-horizon control and specialize
these results to solve a noisy-time variant of the linear quadratic regulator
problem and a portfolio optimization problem with random trade activity rates.
For the linear quadratic case, the optimal controller is linear and can be
computed from a generalization of the classical Riccati differential equation.


title: Explicit Euclidean Embeddings in Permutation Invariant Normed Spaces

abstract:
  Let $(X,\left\Vert \cdot \right\Vert )$ be a real normed space of dimension
$N\in \mathbb{N}$ with a basis $(e_{i})_{1}^{N}$ such that the norm is
invariant under coordinate permutations. Assume for simplicity that the basis
constant is at most $2$. Consider any $n\in \mathbb{N}$ and $0<\varepsilon
<1/4$ such that $n\leq c(\log \varepsilon ^{-1})^{-1}\log N$. We provide an
explicit construction of a matrix that generates a $(1+\varepsilon )$ embedding
of $\ell _{2}^{n}$ into $X$.


title:
Higher order closed-form model for isotropic hyperelastic spherical
  shell (3D solid)

abstract:
  Higher order closed-form formulation for Neo-Hookean shell is presented. New
solution for natural frequency of free vibration of a hemisphere is derived.


title: The number of twists with large torsion of an elliptic curve

abstract:
  For an elliptic curve $E/\Q$, we determine the maximum number of twists
$E^d/\Q$ it can have such that $E^d(\Q)_{tors}\supsetneq E(\Q)[2]$. We use
these results to determine the number of distinct quadratic fields $K$ such
that $E(K)_{tors}\supsetneq E(\Q)_{tors}$. The answer depends on $E(\Q)_{tors}$
and we give the best possible bound for all the possible cases.


title:
Fate of separate chiral transitions at finite $\mu_I$ under the
  influence of mismatched vector interactions

abstract:
  The flavor-mixing induced by the mismatched vector-isoscalar and
vector-isovector interactions at finite baryon chemical potential $\mu$ and
isospin chemical potential $\mu_I$ is demonstrated in the Nambu-Jona-Lasinio
(NJL) type model of QCD. The influence of this non-anomaly flavor-mixing on the
possible separate chiral transitions at nonzero $\mu_I$ is studied under the
assumption of the effective restoration of the $U(1)_A$ symmetry. We find that
for the weak isospin asymmetry, the two separate phase boundaries found
previously can be converted into one only if the vector-isovector coupling
$g_v^v$ is significantly stronger than the vector-isoscalar one $g_v^s$ without
the axial anomaly. When the weak Kabayashi-Maskawa-'t Hooft (KMT) interaction
is included, we find that the separation of the chiral transition with two
critical endpoints for the relatively strong isospin asymmetry can still be
removed owning to the vector interactions. In this case, it is not the vector
coupling difference but the strength of $g_v^v$ which is crucial for the only
phase boundary. We also point out that, in the NJL-type model with mismatched
vector interactions, the recently proposed equivalence for chiral transitions
at finite $\mu$ and $\mu_I$ does not hold even at the mean field approximation.


title: Urban Mobility Scaling: Lessons from `Little Data'

abstract:
  Recent mobility scaling research, using new data sources, often relies on
aggregated data alone. Hence, these studies face difficulties characterizing
the influence of factors such as transportation mode on mobility patterns. This
paper attempts to complement this research by looking at a category-rich
mobility data set. In order to shed light on the impact of categories, as a
case study, we use conventionally collected German mobility data. In contrast
to `check-in'-based data, our results are not biased by Euclidean distance
approximations. In our analysis, we show that aggregation can hide crucial
differences between trip length distributions, when subdivided by categories.
For example, we see that on an urban scale (0 to ~15 km), walking, versus
driving, exhibits a highly different scaling exponent, thus universality class.
Moreover, mode share and trip length are responsive to day-of-week and
time-of-day. For example, in Germany, although driving is relatively less
frequent on Sundays than on Wednesdays, trips seem to be longer. In addition,
our work may shed new light on the debate between distance-based and
intervening-opportunity mechanisms affecting mobility patterns, since mode may
be chosen both according to trip length and urban form.

categories: physics.soc-ph cs.CY cs.SI physics.data-an stat.AP


title: Mislin's theorem for fusion systems via Mackey functors

abstract:
  We state and prove a fusion system version of Mislin's theorem
\cite{Mislin1990} on cohomology and control of fusion, following Symonds's
proof \cite{Symonds2004} of Mislin's theorem using Mackey functors.


title: Go-With-The-Winner: Client-Side Server Selection for Content Delivery

abstract:
  Content delivery networks deliver much of the web and video content in the
world by deploying a large distributed network of servers. We model and analyze
a simple paradigm for client-side server selection that is commonly used in
practice where each user independently measures the performance of a set of
candidate servers and selects the one that performs the best. For web (resp.,
video) delivery, we propose and analyze a simple algorithm where each user
randomly chooses two or more candidate servers and selects the server that
provided the best hit rate (resp., bit rate). We prove that the algorithm
converges quickly to an optimal state where all users receive the best hit rate
(resp., bit rate), with high probability. We also show that if each user chose
just one random server instead of two, some users receive a hit rate (resp.,
bit rate) that tends to zero. We simulate our algorithm and evaluate its
performance with varying choices of parameters, system load, and content
popularity.


title:
Local rings of embedding codepth at most 3 have only trivial
  semidualizing complexes

abstract:
  We prove that a local ring $R$ of embedding codepth at most 3 has at most two
semidualizing complexes up to shift-isomorphism, namely, $R$ itself and a
dualizing $R$-complex if one exists.


title:
Feature Augmentation via Nonparametrics and Selection (FANS) in High
  Dimensional Classification

abstract:
  We propose a high dimensional classification method that involves
nonparametric feature augmentation. Knowing that marginal density ratios are
the most powerful univariate classifiers, we use the ratio estimates to
transform the original feature measurements. Subsequently, penalized logistic
regression is invoked, taking as input the newly transformed or augmented
features. This procedure trains models equipped with local complexity and
global simplicity, thereby avoiding the curse of dimensionality while creating
a flexible nonlinear decision boundary. The resulting method is called Feature
Augmentation via Nonparametrics and Selection (FANS). We motivate FANS by
generalizing the Naive Bayes model, writing the log ratio of joint densities as
a linear combination of those of marginal densities. It is related to
generalized additive models, but has better interpretability and computability.
Risk bounds are developed for FANS. In numerical analysis, FANS is compared
with competing methods, so as to provide a guideline on its best application
domain. Real data analysis demonstrates that FANS performs very competitively
on benchmark email spam and gene expression data sets. Moreover, FANS is
implemented by an extremely fast algorithm through parallel computing.


title: Data-Driven Robust Optimization

abstract:
  The last decade witnessed an explosion in the availability of data for
operations research applications. Motivated by this growing availability, we
propose a novel schema for utilizing data to design uncertainty sets for robust
optimization using statistical hypothesis tests. The approach is flexible and
widely applicable, and robust optimization problems built from our new sets are
computationally tractable, both theoretically and practically. Furthermore,
optimal solutions to these problems enjoy a strong, finite-sample probabilistic
guarantee. \edit{We describe concrete procedures for choosing an appropriate
set for a given application and applying our approach to multiple uncertain
constraints. Computational evidence in portfolio management and queuing confirm
that our data-driven sets significantly outperform traditional robust
optimization techniques whenever data is available.


title:
Measurement of the total cross section of uranium-uranium collisions at
  $\sqrt{s_{NN}}=192.8$ GeV

abstract:
  Heavy ion cross sections totaling several hundred barns have been calculated
previously for the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron
Collider (LHC). These total cross sections are more than an order of magnitude
larger than the geometric ion-ion cross sections primarily due to Bound-Free
Pair Production (BFPP) and Electro-Magnetic Dissociation (EMD). Apart from a
general interest in verifying the calculations experimentally, an accurate
prediction of the losses created in the heavy ion collisions is of practical
interest for the LHC, where some collision products are lost in cryogenically
cooled magnets and have the potential to quench these magnets. In the 2012 RHIC
run uranium ions collided with each other at $\sqrt{s_{NN}} = 192.8$ GeV with
nearly all beam losses due to collisions. This allows for the measurement of
the total cross section, which agrees with the calculated cross section within
the experimental error.


title:
Band Allocation for Cognitive Radios with Buffered Primary and Secondary
  Users

abstract:
  In this paper, we study band allocation of $\mathcal{M}_s$ buffered secondary
users (SUs) to $\mathcal{M}_p$ orthogonal primary licensed bands, where each
primary band is assigned to one primary user (PU). Each SU is assigned to one
of the available primary bands with a certain probability designed to satisfy
some specified quality of service (QoS) requirements for the SUs. In the
proposed system, only one SU is assigned to a particular band. The optimization
problem used to obtain the stability region's envelope (closure) is shown to be
a linear program. We compare the stability region of the proposed system with
that of a system where each SU chooses a band randomly with some assignment
probability. We also compare with a fixed (deterministic) assignment system,
where only one SU is assigned to one of the primary bands all the time. We
prove the advantage of the proposed system over the other systems.


title: Black brane solutions governed by fluxbrane polynomials

abstract:
  A family of composite black brane solutions in the model with scalar fields
and fields of forms is presented. The metric of any solution is defined on a
manifold which contains a product of several Ricci-flat "internal" spaces. The
solutions are governed by moduli functions H_s (s = 1, ..., m) obeying
non-linear differential equations with certain boundary conditions imposed.
These master equations are equivalent to Toda-like equations and depend upon
the non-degenerate (m x m) matrix A. It was conjectured earlier that the
functions H_s should be polynomials if A is a Cartan matrix for some semisimple
finite-dimensional Lie algebra (of rank m). It is shown that the solutions to
master equations may be found by using so-called fluxbrane polynomials which
can be calculated (in principle) for any semisimple finite-dimensional Lie
algebra. Examples of dilatonic charged black hole (0-brane) solutions related
to Lie algebras A_1, A_2, C_2 and G_2 are considered.


title: Dark Matter in Light of LUX

abstract:
  The landscape of dark matter direct detection has been profoundly altered by
the slew of recent experiments. While some have claimed signals consistent with
dark matter, others have seen few, if any, events consistent with dark matter.
The results of the putative detections are often incompatible with each other
in the context of naive spin-independent scattering, as well as with the null
results. In particular, in light of the conflicts between the DM interpretation
of the three events recently reported by the CDMS-Si experiment and the first
results of the LUX experiment, there is a strong need to revisit the
assumptions that go into the DM interpretations of both signals and limits. We
attempt to reexamine a number of particle physics, astrophysics and
experimental uncertainties. Specifically, we examine exothermic scattering,
isospin-dependent couplings, modified halo models through astrophysics
independent techniques, and variations in the assumptions about the
scintillation light in liquid Xenon. We find that only a highly tuned
isospin-dependent scenario remains as a viable explanation of the claimed
detections, unless the scintillation properties of LXe are dramatically
different from the assumptions used by the LUX experiment.


title: Extreme nesting in the conformal loop ensemble

abstract:
  The conformal loop ensemble $\operatorname {CLE}_{\kappa}$ with parameter
$8/3<\kappa<8$ is the canonical conformally invariant measure on countably
infinite collections of noncrossing loops in a simply connected domain. Given
$\kappa$ and $\nu$, we compute the almost-sure Hausdorff dimension of the set
of points $z$ for which the number of CLE loops surrounding the disk of radius
$\varepsilon$ centered at $z$ has asymptotic growth $\nu\log (1/\varepsilon )$
as $\varepsilon \to0$. By extending these results to a setting in which the
loops are given i.i.d. weights, we give a CLE-based treatment of the extremes
of the Gaussian free field.


title: The conformal loop ensemble nesting field

abstract:
  The conformal loop ensemble CLE$_\kappa$ with parameter $8/3 < \kappa < 8$ is
the canonical conformally invariant measure on countably infinite collections
of non-crossing loops in a simply connected domain. We show that the number of
loops surrounding an $\varepsilon$-ball (a random function of $z$ and
$\varepsilon$) minus its expectation converges almost surely as $\varepsilon\to
0$ to a random conformally invariant limit in the space of distributions, which
we call the nesting field. We generalize this result by assigning i.i.d.
weights to the loops, and we treat an alternate notion of convergence to the
nesting field in the case where the weight distribution has mean zero. We also
establish estimates for moments of the number of CLE loops surrounding two
given points.


title:
Hall and Seebeck coefficients from bi-directional charge density wave
  state in high-$T_c$ cuprates

abstract:
  The recent discovery of an incipient charge density wave (CDW) instability
competing with superconductivity in a class of high temperature cuprate
superconductors has brought the role of charge order in the cuprate phase
diagram under renewed focus. Here we take a mean field (Q = 2pi/3,2pi/3)
bi-axial CDW state and calculate the Fermi surface topology and the resulting
Hall and Seebeck coefficients as a function of temperature and hole doping. We
show that, in the appropriate doping ranges where the low temperature state (in
the absence of superconductivity) is a bi-directional CDW, the Fermi surface
consists of electron pockets, resulting in the Hall and Seebeck coefficients
becoming negative at low temperatures as seen in experiments.


title: Trees in Random Sparse Graphs with a Given Degree Sequence

abstract:
  Let $\mathbb{G}^{D}$ be the set of graphs $G(V,\, E)$ with
$\left|V\right|=n$, and the degree sequence equal to $D=(d_{1},\,
d_{2},\,\dots,\, d_{n})$. In addition, for $\frac{1}{2}<a<1$, we define the set
of graphs with an almost given degree sequence $D$ as follows, \[
\mathbb{G}_{a}^{D}:=\cup\,\mathbb{G}^{\bar{D}}, \] where the union is over all
degree sequences $\bar{D}$ such that, for $1\leq i\leq n$, we have
$\left|d_{i}-\bar{d}_{i}\right|<d_{i}^{a}$.
  Now, if we chose random graphs $\mathcal{G}_{\mathbf{g}}\left(D\right)$ and
$\mathcal{G}_{\mathbf{a}}\left(D\right)$ uniformly out of the sets
$\mathbb{G}^{D}$ and $\mathbb{G}_{a}^{D}$, respectively, what do they look
like? This has been studied when $\mathcal{G}_{\mathbf{g}}\left(D\right)$ is a
dense graph, i.e. $\left|E\right|=\Theta(n^{2})$, in the sense of graphons, or
when $\mathcal{G}_{\mathbf{g}}\left(D\right)$ is very sparse, i.e.
$d_{n}^{2}=o(\left|E\right|)$. In the case of sparse graphs with an almost
given degree sequence, we investigate this question, and give the finite tree
subgraph structure of $\mathcal{G}_{\mathbf{a}}\left(D\right)$ under some mild
conditions. For the random graph $\mathcal{G}_{\mathbf{g}}\left(D\right)$ with
a given degree sequence, we re-derive the finite tree structure in dense and
very sparse cases to give a continuous picture.
  Moreover, for a pair of vectors
$\left(D_{1},D_{2}\right)\in\mathbb{Z}^{n_{1}}\times\mathbb{Z}^{n_{2}}$, we let
$\mathcal{G}_{\mathbf{b}}\left(D_{1},D_{2}\right)$ be the random bipartite
graph that is chosen uniformly out of the set $\mathbb{G}^{D_{1},D_{2}}$, where
$\mathbb{G}^{D_{1},D_{2}}$ is the set of all bipartite graphs with the degree
sequence $\left(D_{1},D_{2}\right)$. We are able to show the result for
$\mathcal{G}_{\mathbf{b}}\left(D_{1},D_{2}\right)$ without any further
conditions.


title: Invisible Z' and dark matter: LHC vs LUX constraints

abstract:
  We consider a simple, yet generic scenario in which a new heavy $Z'$ gauge
boson couples both to SM fermions and to dark matter. In this framework we
confront the best LHC limits on an extra gauge boson $Z'$ to the constraints on
couplings to dark matter from direct detection experiments. In particular we
show that the LHC searches for resonant production of dileptons and the recent
exclusion limits obtained by the LUX collaboration give complementary
constraints. Together, they impose strong bounds on the invisible branching
ratio and exclude a large part of the parameter space for generic $Z'$ models.
Our study encompasses many possible $Z'$ models, including SSM, $E_6$-inspired
or B-L scenario.


title:
Coupled multiphysics, barrier localization, and critical radius effects
  in embedded nanowire superlattices

abstract:
  The new contribution of this paper is to develop a cylindrical representation
of an already known multiphysics model for embedded nanowire superlattices
(NWSLs) of wurtzite structure that includes a coupled, strain dependent 8-band
$\mathbf{k\cdot p}$ Hamiltonian in cylindrical coordinates and investigate the
influence of coupled piezo-electromechanical effects on the barrier
localization and critical radius in such NWSLs. The coupled
piezo-electromechanical model for semiconductor materials takes into account
the strain, piezoelectric effects and spontaneous polarization. Based on the
developed 3D model, the band structures of electrons (holes) obtained from
results of modeling in Cartesian coordinates are in good agreement with those
values obtained from our earlier developed 2D model in cylindrical coordinates.
Several parameters such as lattice mismatch, piezo-electric fields, valence and
conduction band offsets at the heterojunction of $\mathrm{Al_xGa_{1-x}N/GaN}$
supperlattice can be varied as a function of the Al mole fraction. When the
band offsets at the heterojunction of $\mathrm{Al_xGa_{1-x}N/GaN}$ are very
small and the influence of the piezo-electromechanical effects can be
minimized, then the barrier material can no longer be treated as an infinite
potential well. In this situation, it is possible to visualize the penetration
of the Bloch wave function into the barrier material that provides an
estimation of critical radii of NWSLs. In this case, the NWSLs can act as
inversion layers. Finally, we investigate the influence of symmetry of the
square and cylindrical NWSLs on the band structures of electrons in the
conduction band.


title: Unbalanced Allocations

abstract:
  We consider the unbalanced allocation of $m$ balls into $n$ bins by a
randomized algorithm using the "power of two choices". For each ball, we select
a set of bins at random, then place the ball in the fullest bin within the set.
Applications of this generic algorithm range from cost minimization to
condensed matter physics. In this paper, we analyze the distribution of the bin
loads produced by this algorithm, considering, for example, largest and
smallest loads, loads of subsets of the bins, and the likelihood of bins having
equal loads.


title:
Linear-Time Algorithms for Finding Tucker Submatrices and
  Lekkerkerker-Boland Subgraphs

abstract:
  Lekkerkerker and Boland characterized the minimal forbidden induced subgraphs
for the class of interval graphs. We give a linear-time algorithm to find one
in any graph that is not an interval graph. Tucker characterized the minimal
forbidden submatrices of binary matrices that do not have the consecutive-ones
property. We give a linear-time algorithm to find one in any binary matrix that
does not have the consecutive-ones property.


title:
Local index theory for certain Fourier integral operators on Lie
  groupoids

abstract:
  We develop a local index theory for Fourier-integral operators associated to
non-proper and non-isometric actions of Lie groupoids on smooth submersions. To
such action is associated a short exact sequence of algebras, relating genuine
Fourier-integral operators to their non-commutative symbol. We then compute the
connecting map induced by this extension on periodic cyclic cohomology. When
cyclic cohomology is localized at appropriate isotropic submanifolds of the
groupoid in question, we find that the connecting map is expressed in terms of
an explicit Wodzicki-type residue formula, which involves the jets of
non-commutative symbols at the fixed-point set of the action.


title:
Nonuniform growth and topological defects in the shaping of elastic
  sheets

abstract:
  Programming the non-uniform growth of a responsive polymer gel has emerged as
a powerful tool to shape sheets into prescribed three dimensional shapes. We
demonstrate that shapes with zero Gaussian curvature, except at singularities,
produced by the growth-induced buckling of a thin elastic sheet are the same as
those produced by the Volterra construction of topological defects in which
edges of an intrinsically flat surface are identified. With this connection, we
study the problem of choosing an optimal pattern of growth for a prescribed
developable surface, finding a fundamental trade-off between optimal design and
the accuracy of the resulting shape which can be quantified by the length along
which an edge should be identified.


title: Tuning Magnetic Properties Polycrystalline of PtCo Alloys Films with Pt

abstract:
  We experimentally investigated disordered PtxCo1-x (here x: 0.4, 0.5 and 0.6)
alloy thin films magnetic properties which depended on Pt content. The magnetic
properties of PtCo films were described with two effects, one of them is the
hybridization between Co 3d and Pt 5d energy levels and it causes Pt magnetic
polarization. The second one is the high spin orbit coupling constant of Pt
which increases the ratio of magnetic orbital moment to spin moment. We
investigated magnetic properties considering these effects by vibrating sample
magnetometer (VSM) and ferromagnetic resonance (FMR) techniques.