title:
Lifting Group Actions, Equivariant Towers and Subgroups of
  Non-positively Curved Groups

abstract:
  If $\mathcal C$ is a class of complexes closed under taking full subcomplexes
and covers and $\mathcal G$ is the class of groups admitting proper and
cocompact actions on one-connected complexes in $\mathcal C$, then $\mathcal G$
is closed under taking finitely presented subgroups. As a consequence the
following classes of groups are closed under taking finitely presented
subgroups: groups acting geometrically on regular $CAT(0)$ simplicial complexes
of dimension $3$, $k$-systolic groups for $k\geq 6$, and groups acting
geometrically on $2$-dimensional negatively curved complexes. We also show that
there is a finite non-positively curved cubical $3$-complex which is not
homotopy equivalent to a finite non-positively curved regular simplicial
$3$-complex. We included other applications to relatively hyperbolic groups and
diagramatically reducible groups. The main result is obtained by developing a
notion of equivariant towers which is of independent interest.


title:
From Design to Implementation: an Automated, Credible Autocoding Chain
  for Control Systems

abstract:
  This article describes a fully automated, credible autocoding chain for
control systems. The framework generates code, along with guarantees of high
level functional properties which can be independently verified. It relies on
domain specific knowledge and fomal methods of analysis to address a context of
heightened safety requirements for critical embedded systems and
ever-increasing costs of verification and validation. The platform strives to
bridge the semantic gap between domain expert and code verification expert.
First, a graphical dataflow language is extended with annotation symbols
enabling the control engineer to express high level properties of its control
law within the framework of a familiar language. An existing autocoder is
enhanced to both generate the code implementing the initial design, but also to
carry high level properties down to annotations at the level of the code.
Finally, using customized code analysis tools, certificates are generated which
guarantee the correctness of the annotations with respect to the code, and can
be verified using existing static analysis tools. Only a subset of properties
and controllers are handled at this point.


title:
Structure controllability of complex network based on preferential
  matching

abstract:
  Minimum driver node sets (MDSs) play an important role in studying the
structural controllability of complex networks. Recent research has shown that
MDSs tend to avoid high-degree nodes. However, this observation is based on the
analysis of a small number of MDSs, because enumerating all of the MDSs of a
network is a #P problem. Therefore, past research has not been sufficient to
arrive at a convincing conclusion. In this paper, first, we propose a
preferential matching algorithm to find MDSs that have a specific degree
property. Then, we show that the MDSs obtained by preferential matching can be
composed of high- and medium-degree nodes. Moreover, the experimental results
also show that the average degree of the MDSs of some networks tends to be
greater than that of the overall network, even when the MDSs are obtained using
previous research method. Further analysis shows that whether the driver nodes
tend to be high-degree nodes or not is closely related to the edge direction of
the network.


title:
CRPropa 3.0 - a Public Framework for Propagating UHE Cosmic Rays through
  Galactic and Extragalactic Space

abstract:
  The interpretation of experimental data of ultra-high energy cosmic rays
(UHECRs) above 10^17 eV is still under controversial debate. The development
and improvement of numerical tools to propagate UHECRs in galactic and
extragalactic space is a crucial ingredient to interpret data and to draw
conclusions on astrophysical parameters. In this contribution the next major
release of the publicly available code CRPropa (3.0) is presented. It reflects
a complete redesign of the code structure to facilitate high performance
computing and comprises new physical features such as an interface for galactic
propagation using lensing techniques and inclusion of cosmological effects in a
three-dimensional environment. The performance is benchmarked and first
applications are presented.


title:
An Analytic Bolometric Light Curve Model of Interaction-Powered
  Supernovae and its Application to Type IIn Supernovae

abstract:
  We present an analytic model for bolometric light curves which are powered by
the interaction between supernova ejecta and a dense circumstellar medium. This
model is aimed at modeling Type IIn supernovae to determine the properties of
their supernova ejecta and circumstellar medium. Our model is not restricted to
the case of steady mass loss and can be applied broadly. We only consider the
case in which the optical depth of the unshocked circumstellar medium is not
high enough to affect the light curves. We derive the luminosity evolution
based on an analytic solution for the evolution of a dense shell created by the
interaction. We compare our model bolometric light curves to observed
bolometric light curves of three Type IIn supernovae (2005ip, 2006jd, 2010jl)
and show that our model can constrain their supernova ejecta and circumstellar
medium properties. Our analytic model is supported by numerical light curves
from the same initial conditions.


title: Non-Collision singularities in the Planar two-Center-two-Body problem

abstract:
  In this paper, we study a model of simplified four-body problem called planar
two-center-two-body problem. In the plane, we have two fixed centers
$Q_1=(-\chi,0)$, $Q_2=(0,0)$ of masses 1, and two moving bodies $Q_3$ and $Q_4$
of masses $\mu\ll 1$. They interact via Newtonian potential. $Q_3$ is captured
by $Q_2$, and $Q_4$ travels back and forth between two centers. Based on a
model of Gerver, we prove that there is a Cantor set of initial conditions
which lead to solutions of the Hamiltonian system whose velocities are
accelerated to infinity within finite time avoiding all early collisions. We
consider this model as a simplified model for the planar four-body problem case
of the Painlev\'{e} conjecture.


title: An extremal problem for characteristic functions

abstract:
  Suppose $E$ is a subset of the unit circle $\mathbb{T}$ and $H^\infty\subset
L^\infty$ is the Hardy subalgebra. We examine the problem of finding the
distance from the characteristic function of $E$ to $z^nH^\infty$. This admits
an alternate description as a dual extremal problem. Precise solutions are
given in several important cases. The techniques used involve the theory of
Toeplitz and Hankel operators as well as the construction of certain conformal
mappings.


title: Pionic Dark Matter

abstract:
  We study a phenomenological model where the lightest dark matter (DM)
particles are the pseudo-Goldstone excitations associated with a spontaneously
broken symmetry, and transforming linearly with respect to an unbroken group H.
For definiteness we take H = SU(N) and assume the Goldstone particles are
bosons; in parallel with QCD, we refer to these particles as dark-matter pions.
This scenario is in contrast to the common assumption that DM fields transform
linearly under the full symmetry of the model. We illustrate the formalism by
treating in detail the case of H = SU(2), in particular we calculate all the
interactions relevant for the Boltzmann equations, which we solve numerically;
we also derive approximate analytic solutions and show their consistency with
the numerical results. We then compare the results with the constraints derived
from the cold DM and direct detection experiments and derive the corresponding
restrictions on the model parameters.


title:
Scaling of spin Hall angle in 3d, 4d and 5d metals from Y3Fe5O12/metal
  spin pumping

abstract:
  Pure spin currents generated by spin pumping in ferromagnet/nonmagnet (FM/NM)
bilayers produce inverse spin Hall effect (ISHE) voltages in the NM, from which
spin pumping and transport characteristics of the NM can be extracted. Due to
its exceptionally low damping, Y3Fe5O12 (YIG) is an important and widely used
FM for microwave devices and ferromagnetic resonance (FMR) spin pumping. Here
we report systematic investigation of spin pumping from 20-nm thick YIG thin
films to a series of 3d, 4d and 5d normal metals (Cu, Ag, Ta, W, Pt and Au)
with various spin-orbit coupling strengths. From enhanced Gilbert damping
obtained from the frequency dependence of FMR linewidths and ISHE signals, the
spin Hall angles and YIG/NM interfacial spin mixing conductances are
quantitatively determined for these metals. The spin Hall angles largely vary
as the fourth power of the atomic number, corroborating the dominant role of
spin-orbit coupling across a broad range in the inverse spin Hall effect.


title:
Trapping effect of periodic structures on the thermodynamic properties
  of Fermi and Bose gases

abstract:
  We report the thermodynamic properties of Bose and Fermi ideal gases immersed
in periodic structures such as penetrable multilayers or multitubes simulated
by one (planes) or two perpendicular (tubes) external Dirac comb potentials,
while the particles are allowed to move freely in the remaining directions.
Although the bosonic chemical potential is a constant for $T < T_c$, a non
decreasing with temperature anomalous behavior of the fermionic chemical
potential is confirmed and monitored as the tube bundle goes from 2D to 1D when
the wall impenetrability overcomes a critical value. In the specific heat
curves dimensional crossovers are very noticeable at high temperatures for both
gases, where the system behavior goes from 3D to 2D and latter to 1D as the
wall impenetrability is increased.


title: Long-term X-ray emission from Swift J1644+57

abstract:
  The X-ray emission from Swift J1644+57 is not steadily decreasing instead it
shows multiple pulses with declining amplitudes. We model the pulses as reverse
shocks from collisions between the late ejected shells and the externally
shocked material, which is decelerated while sweeping the ambient medium. The
peak of each pulse is taken as the maximum emission of each reverse shock. With
a proper set of parameters, the envelope of peaks in the light curve as well as
the spectrum can be modelled nicely.


title: Hadronic and hybrid stars subject to density dependent magnetic fields

abstract:
  In this work we present a study of magnetars composed of hadronic and quark
matter, under the influence of strong magnetic fields. We present our results
for hadronic matter taking into account the effects that the inclusion of
anomalous magnetic moment corrections may cause on the equations of state
(EOS). Particle abundances are also presented and discussed. Additionally, the
case of hybrid stars under the influence of strong magnetic fields is
considered. We study the structure of hybrid stars based on the Maxwell
condition (without a mixed phase), where the hadron phase is described by the
non-linear Walecka model (NLW) and the quark phase by the Nambu-Jona-Lasinio
model (NJL). The EOS and the mass-radius relation for each case are calculated
and discussed. We show that the recently observed high mass neutron stars can
be described by both hadronic and hybrid equations of state subject to strong
magnetic fields.


title:
Trace ideal criteria for embeddings and composition operators on model
  spaces

abstract:
  Let $K_\theta$ be a model space generated by an inner function $\theta$. We
study the Schatten class membership of embeddings $I : K_\theta \to L^2(\mu)$,
$\mu$ a positive measure, and of composition operators $C_\phi:K_\theta\to
H^2(\mathbb D)$ with a holomprphic function $\phi:\mathbb D\rightarrow \mathbb
D$. In the case of one-component inner functions $\theta$ we show that the
problem can be reduced to the study of natural extensions of $I$ and $C_\phi$
to the Hardy-Smirnov space $E^2(D)$ in some domain $D\supset \mathbb D$. In
particular, we obtain a characterization of Schatten membership of $C_\phi$ in
terms of Nevanlinna counting function. By example this characterization does
not hold true for general $\phi$.


title: Formation of the Smectic-B Crystal from a Simple Monatomic Liquid

abstract:
  We report a molecular dynamics simulation demonstrating that the Smectic B
crystalline phase (Cr-B), commonly observed in mesogenic systems of anisotropic
molecules, can be formed by a system of identical particles interacting via a
spherically symmetric potential. The Cr-B phase forms as a result of a first
order transition from an isotropic liquid phase upon isochoric cooling at
appropriate number density. Its structure, determined by the design of the pair
potential corresponds to Cr-B structure formed by elongated particles with the
aspect ratio 1.8. The diffraction pattern, and the real-space structure
inspection demonstrate dominance of the ABC-type of axial layer stacking. This
result opens a general possibility of producing smectic phases using isotropic
interparticle interaction both in simulations and in colloidal systems.


title: Long range interactions of ytterbium in mixed quantum gases

abstract:
  We present methods for accurate evaluation of van der Waals coefficients of
dimers with excited atoms that have a strong decay channel. We calculate C_6
coefficients for the Yb-Yb 1S_0+ 3P_{0,1}, 3P_0+3P_0 and Yb-Rb 3P_1+5s, 1S_0+
5p_{1/2} dimers and C_8 coefficients for the Yb-Yb 1S_0+1S_0, 1S_0+3P_1 and
Yb-Rb 1S_0+5s dimers. We evaluate uncertainties of all properties.

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


title:
Collective excitations of an imbalanced fermion gas in a 1D optical
  lattice

abstract:
  The collective excitations that minimize the Helmholtz free energy of a
population-imbalanced mixture of a $^{6}$Li gas loaded in a quasi
one-dimensional optical lattice are obtained. These excitations reveal a
rotonic branch after solving the Bethe-Salpeter equation under a generalized
random phase approximation based on a single-band Hubbard Hamiltonian. The
phase diagram describing stability regions of Fulde-Farrell-Larkin-Ovchinnikov
and Sarma phases is also analyzed.


title: Long range interaction coefficients for ytterbium dimers

abstract:
  We evaluate the electric-dipole and electric-quadrupole static and dynamic
polarizabilities for the 6s^2 ^1S_0, 6s6p ^3P_0, and 6s6p ^3P_1 states and
estimate their uncertainties. A methodology is developed for an accurate
evaluation of the van der Waals coefficients of dimers involving excited state
atoms with strong decay channel to the ground state. This method is used for
evaluation of the long range interaction coefficients of particular
experimental interest, including the C_6 coefficients for the Yb-Yb
^1S_0+^3P_{0,1} and ^3P_0+^3P_0 dimers and C_8 coefficients for the ^1S_0+^1S_0
and ^1S_0+^3P_1 dimers.


title:
Intrinsic Colors, Temperatures, and Bolometric Corrections of Pre-Main
  Sequence Stars

abstract:
  We present an analysis of the intrinsic colors and temperatures of 5-30 Myr
old pre-main sequence (pre-MS) stars using the F0 through M9 type members of
nearby, negligibly reddened groups: Eta Cha cluster, TW Hydra Association, Beta
Pic Moving Group, and Tucana-Horologium Association. To check the consistency
of spectral types from the literature, we estimate new spectral types for 52
nearby pre-MS stars with spectral types F3 through M4 using optical spectra
taken with the SMARTS 1.5-m telescope. Combining these new types with published
spectral types, and photometry from the literature (Johnson-Cousins BVIc, 2MASS
JHKs and WISE W1, W2, W3, and W4), we derive a new empirical spectral
type-color sequence for 5-30 Myr old pre-MS stars. Colors for pre-MS stars
match dwarf colors for some spectral types and colors, but for other spectral
types and colors, deviations can exceed 0.3 mag. We estimate effective
temperatures (Teff) and bolometric corrections (BCs) for our pre-MS star sample
through comparing their photometry to synthetic photometry generated using the
BT-Settl grid of model atmosphere spectra. We derive a new Teff and BC scale
for pre-MS stars, which should be a more appropriate match for T Tauri stars
than often-adopted dwarf star scales. While our new Teff scale for pre-MS stars
is within ~100 K of dwarfs at a given spectral type for stars <G5, for G5
through K6, the pre-MS stars are ~250 K cooler than their main sequence
counterparts. Lastly, we present (1) a modern Teff, optical/IR color, and
bolometric correction sequence for O9V-M9V MS stars based on an extensive
literature survey, (2) a revised Q-method relation for dereddening UBV
photometry of OB-type stars, and (3) introduce two candidate spectral standard
stars as representatives of spectral types K8V and K9V.


title: Comparison principle, stochastic completeness and half-space theorems

abstract:
  We present a criterion for the stochastic completeness of a submanifold in
terms of its distance to a hypersurface in the ambient space. This relies in a
suitable version of the Hessian comparison theorem. In the sequel we apply a
comparison principle with geometric barriers for establishing mean curvature
estimates for stochastically complete submanifolds in Riemannian products,
Riemannian submersions and wedges. These estimates are applied for obtaining
both horizontal and vertical half-space theorems for submanifolds in
$\mathbb{H}^n \times \mathbb{R}^\ell$.


title:
Interaction effects on topological phase transitions via numerically
  exact quantum Monte Carlo calculations

abstract:
  We theoretically study topological phase transitions in four generalized
versions of the Kane-Mele-Hubbard model with up to $2\times 18^2$ sites. All
models are free of the fermion-sign problem allowing numerically exact quantum
Monte Carlo (QMC) calculations to be performed to extremely low temperatures.
We numerically compute the $\mathbb{Z}_2$ invariant and spin Chern number
$C_\sigma$ directly from the zero-frequency single-particle Green's functions,
and study the topological phase transitions driven by the tight-binding
parameters at different on-site interaction strengths. The $\mathbb{Z}_2$
invariant and spin Chern number, which are complementary to each another,
characterize the topological phases and identify the critical points of
topological phase transitions. Although the numerically determined phase
boundaries are nearly identical for different system sizes, we find strong
system-size dependence of the spin Chern number, where quantized values are
only expected upon approaching the thermodynamic limit. For the Hubbard models
we considered, the QMC results show that correlation effects lead to shifts in
the phase boundaries relative to those in the non-interacting limit, without
any spontaneously symmetry breaking. The interaction-induced shift is
non-perturbative in the interactions and cannot be captured within a "simple"
self-consistent calculation either, such as Hartree-Fock. Furthermore, our QMC
calculations suggest that quantum fluctuations from interactions stabilize
topological phases in systems where the one-body terms preserve the $D_3$
symmetry of the lattice, and destabilize topological phases when the one-body
terms break the $D_3$ symmetry.


title: Construction of f(R) Gravity Models

abstract:
  In this paper, we study how to construct f(R) gravity models. Cosmological
observations and local gravity tests imply that a viable f(R) model should be
very close to the LCDM model. We create procedures to construct viable
LCDM-like f(R) models, and present multiple models of three types. The
connections between some of these models are discussed. We also study the
cosmological evolution of the LCDM-like f(R) gravity. Exact numerical
integration can generate accurate cosmological evolution, but the numerical
simulation in the early-universe stage is slow due to the oscillations of the
field phi(= f') near the minimum of the effective potential. To avoid this
problem, we take the minimum of the effective potential as an approximate
solution for phi, and obtain the cosmological evolution. This approximate
method describes the cosmological evolution well except in the late universe.
Therefore, we use the approximate method in the early-universe evolution, and
use the exact method in the late-universe one.


title: On IEEE 802.11: Wireless LAN Technology

abstract:
  Network technologies are traditionally based on wireline solutions. But the
introduction of the IEEE 802.11 standards have made a huge impact on the market
such that laptops, PCs, printers, cellphones, and VoIP phones, MP3 players in
our homes, in offices and even in public areas have incorporated the wireless
LAN technology. Wireless broadband technologies nowadays provide unlimited
broadband access to users which were previously offered only to wireline users.
In this paper, we review and summarize one of the emerging wireless broadband
technology i.e. IEEE 802.11,which is a set of physical layer standard for
implementing wireless local area network computer communication in the
2.4,3.6,5 and 60GHz frequency band. They fix technology issues or add
functionality which is expected to be required by future applications. Though
some of the earlier versions of these technologies are obsolete (such as
HiperLAN) now but still we have included them in this review for the sake of
completeness.


title:
Statistical Inferences Using Large Estimated Covariances for Panel Data
  and Factor Models

abstract:
  While most of the convergence results in the literature on high dimensional
covariance matrix are concerned about the accuracy of estimating the covariance
matrix (and precision matrix), relatively less is known about the effect of
estimating large covariances on statistical inferences. We study two important
models: factor analysis and panel data model with interactive effects, and
focus on the statistical inference and estimation efficiency of structural
parameters based on large covariance estimators. For efficient estimation, both
models call for a weighted principle components (WPC), which relies on a high
dimensional weight matrix. This paper derives an efficient and feasible WPC
using the covariance matrix estimator of Fan et al. (2013). However, we
demonstrate that existing results on large covariance estimation based on
absolute convergence are not suitable for statistical inferences of the
structural parameters. What is needed is some weighted consistency and the
associated rate of convergence, which are obtained in this paper. Finally, the
proposed method is applied to the US divorce rate data. We find that the
efficient WPC identifies the significant effects of divorce-law reforms on the
divorce rate, and it provides more accurate estimation and tighter confidence
intervals than existing methods.


title: On the origin of GeV emission in gamma-ray bursts

abstract:
  The most common progenitors of gamma-ray bursts (GRBs) are massive stars with
strong stellar winds. We show that the GRB blast wave in the wind should emit a
bright GeV flash. It is produced by inverse Compton cooling of the thermal
plasma behind the forward shock wave. The main part of the flash is shaped by
scattering of the prompt MeV radiation (emitted at smaller radii) which streams
through the external blast wave. The inverse-Compton flash is bright due to the
huge e+- enrichment of the external medium. At late times, the blast wave
switches to normal synchrotron-self-Compton cooling. The mechanism is
demonstrated by a detailed transfer simulation. The observed prompt MeV
radiation is taken as an input of the simulation; we use GRB 080916C as an
example. The result reproduces the GeV flash observed by the Fermi telescope.
It explains the delayed onset, the steep rise, the peak flux, the time of the
peak, the long smooth decline, and the spectral slope of GeV emission. The wind
density required to reproduce all these features is typical of Wolf-Rayet
stars. Our simulation predicts strong TeV emission 1 min after the burst
trigger; then a cutoff in the observed high-energy spectrum is expected from
absorption by extragalactic background light. In addition, a bright optical
counterpart of the GeV flash is predicted for plausible values of the magnetic
field; such a double (optical+GeV) flash has been observed in GRB 130427A.


title:
Far-Ultraviolet Observations of the Spica Nebula and the Interaction
  Zone

abstract:
  We report the analysis results of far ultraviolet (FUV) observations, made
for a broad region around $\alpha$ Vir (Spica) including the interaction zone
of Loop I and the Local Bubble. The whole region was optically thin and a
general correlation was seen between the FUV continuum intensity and the dust
extinction, except in the neighborhood of the bright central star, indicating
the dust scattering nature of the FUV continuum. We performed Monte-Carlo
radiative transfer simulations to obtain the optical parameters related to the
dust scattering as well as the geometrical structure of the region. The albedo
and asymmetry factor were found to be 0.38$\pm$0.06 and 0.46$\pm$0.06,
respectively, in good agreement with the Milky Way dust grain models. The
distance to and the thickness of the interaction zone were estimated to be
70$^{+4}_{-8}$ pc and 40$^{+8}_{-10}$ pc, respectively. The diffuse FUV
continuum in the northern region above Spica was mostly the result of
scattering of the starlight from Spica, while that in the southern region was
mainly due to the background stars. The \ion{C}{4} $\lambda\lambda$1548, 1551
emission was found throughout the whole region, in contrast to the \ion{Si}{2}*
$\lambda$1532 emission which was bright only within the \ion{H}{2} region. This
indicates that the \ion{C}{4} line arises mostly at the shell boundaries of the
bubbles, with a larger portion likely from the Loop I than from the Local
Bubble side, whereas the \ion{Si}{2}* line is from the photoionized Spica
nebula.


title:
A direct solver with O(N) complexity for variable coefficient elliptic
  PDEs discretized via a high-order composite spectral collocation method

abstract:
  A numerical method for solving elliptic PDEs with variable coefficients on
two-dimensional domains is presented. The method is based on high-order
composite spectral approximations and is designed for problems with smooth
solutions. The resulting system of linear equations is solved using a direct
(as opposed to iterative) solver that has optimal O(N) complexity for all
stages of the computation when applied to problems with non-oscillatory
solutions such as the Laplace and the Stokes equations. Numerical examples
demonstrate that the scheme is capable of computing solutions with relative
accuracy of $10^{-10}$ or better, even for challenging problems such as highly
oscillatory Helmholtz problems and convection-dominated convection diffusion
equations. In terms of speed, it is demonstrated that a problem with a
non-oscillatory solution that was discretized using $10^{8}$ nodes was solved
in 115 minutes on a personal work-station with two quad-core 3.3GHz CPUs. Since
the solver is direct, and the "solution operator" fits in RAM, any solves
beyond the first are very fast. In the example with $10^{8}$ unknowns, solves
require only 30 seconds.


title:
Hierarchical interpolative factorization for elliptic operators:
  integral equations

abstract:
  This paper introduces the hierarchical interpolative factorization for
integral equations (HIF-IE) associated with elliptic problems in two and three
dimensions. This factorization takes the form of an approximate generalized LU
decomposition that permits the efficient application of the discretized
operator and its inverse. HIF-IE is based on the recursive skeletonization
algorithm but incorporates a novel combination of two key features: (1) a
matrix factorization framework for sparsifying structured dense matrices and
(2) a recursive dimensional reduction strategy to decrease the cost. Thus,
higher-dimensional problems are effectively mapped to one dimension, and we
conjecture that constructing, applying, and inverting the factorization all
have linear or quasilinear complexity. Numerical experiments support this claim
and further demonstrate the performance of our algorithm as a generalized fast
multipole method, direct solver, and preconditioner. HIF-IE is compatible with
geometric adaptivity and can handle both boundary and volume problems. MATLAB
codes are freely available.


title: Counting using Hall Algebras III. Quivers with Potentials

abstract:
  For a quiver with potential, we can associate a vanishing cycle to each
representation space. If there is a nice torus action on the potential, the
vanishing cycles can be expressed in terms of truncated Jacobian algebras. We
study how these vanishing cycles change under the mutation of
Derksen-Weyman-Zelevinsky. The wall-crossing formula leads to a
categorification of quantum cluster algebras under some assumption. This is a
special case of A. Efimov's result, but our approach is more concrete and
down-to-earth. We also obtain a counting formula relating the representation
Grassmannians under sink-source reflections.


title: Bayesian Quantile Regression for Partially Linear Additive Models

abstract:
  In this article, we develop a semiparametric Bayesian estimation and model
selection approach for partially linear additive models in conditional quantile
regression. The asymmetric Laplace distribution provides a mechanism for
Bayesian inferences of quantile regression models based on the check loss. The
advantage of this new method is that nonlinear, linear and zero function
components can be separated automatically and simultaneously during model
fitting without the need of pre-specification or parameter tuning. This is
achieved by spike-and-slab priors using two sets of indicator variables. For
posterior inferences, we design an effective partially collapsed Gibbs sampler.
Simulation studies are used to illustrate our algorithm. The proposed approach
is further illustrated by applications to two real data sets.


title:
Text Categorization via Similarity Search: An Efficient and Effective
  Novel Algorithm

abstract:
  We present a supervised learning algorithm for text categorization which has
brought the team of authors the 2nd place in the text categorization division
of the 2012 Cybersecurity Data Mining Competition (CDMC'2012) and a 3rd prize
overall. The algorithm is quite different from existing approaches in that it
is based on similarity search in the metric space of measure distributions on
the dictionary. At the preprocessing stage, given a labeled learning sample of
texts, we associate to every class label (document category) a point in the
space of question. Unlike it is usual in clustering, this point is not a
centroid of the category but rather an outlier, a uniform measure distribution
on a selection of domain-specific words. At the execution stage, an unlabeled
text is assigned a text category as defined by the closest labeled neighbour to
the point representing the frequency distribution of the words in the text. The
algorithm is both effective and efficient, as further confirmed by experiments
on the Reuters 21578 dataset.


title: Fock-Sobolev spaces of fractional order

abstract:
  For the full range of index $0<p\leq\infty$, real weight $\alpha$ and real
Sobolev order $s$, two types of weighted Fock-Sobolev spaces over $\mathbb
C^n$, $F^p_{\alpha, s}$ and $\widetilde F^p_{\alpha,s}$, are introduced through
fractional differentiation and through fractional integration, respectively. We
show that they are the same with equivalent norms and, furthermore, that they
are identified with the weighted Fock space $F^p_{\alpha-sp,0}$ for the full
range of parameters. So, the study on the weighted Fock-Sobolev spaces is
reduced to that on the weighted Fock spaces. We describe explicitly the
reproducing kernels for the weighted Fock spaces and then establish the
boundedness of integral operators induced by the reproducing kernels. We also
identify dual spaces, obtain complex interpolation result and characterize
Carleson measures.


title:
Copper Replaces Tin: A Copper based Gelling Catalyst for Poly-Urethane
  from Discarded Motherboard

abstract:
  A discarded motherboard based eco-friendly copper catalyst has been
programmed to replace the industrially used tin based catalyst DBTDL. The
catalyst has been characterized by UV-Vis spectroscopy, FT-IR and TEM. Using
the catalyst reaction conditions is optimized and under the optimized
condition, both polyurethane and polyurethane foam are prepared, thus proving
the generality of the catalyst to be used in industries. A possible mechanism
has also been proposed.


title: Index Coding Problem with Side Information Repositories

abstract:
  To tackle the expected enormous increase in mobile video traffic in cellular
networks, an architecture involving a base station along with caching femto
stations (referred to as helpers), storing popular files near users, has been
proposed [1]. The primary benefit of caching is the enormous increase in
downloading rate when a popular file is available at helpers near a user
requesting that file. In this work, we explore a secondary benefit of caching
in this architecture through the lens of index coding. We assume a system with
n users and constant number of caching helpers. Only helpers store files, i.e.
have side information. We investigate the following scenario: Each user
requests a distinct file that is not found in the set of helpers nearby. Users
are served coded packets (through an index code) by an omniscient base station.
Every user decodes its desired packet from the coded packets and the side
information packets from helpers nearby. We assume that users can obtain any
file stored in their neighboring helpers without incurring transmission costs.
With respect to the index code employed, we investigate two achievable schemes:
1) XOR coloring based on coloring of the side information graph associated with
the problem and 2)Vector XOR coloring based on fractional coloring of the side
information graph. We show that the general problem reduces to a canonical
problem where every user is connected to exactly one helper under some
topological constraints. For the canonical problem, with constant number of
helpers (k), we show that the complexity of computing the best XOR/vector XOR
coloring schemes are polynomial in the number of users n. The result exploits a
special complete bi-partite structure that the side information graphs exhibit
for any finite k.


title: Seeding ice growth at ambient conditions using nano graphene oxide

abstract:
  Water wetting on a hydrophobic surface at ambient conditions is disallowed by
the nonpolar nature of the surface and high vapor pressure of water. However,
the presence of sub-millimeter sized hydrophilic patches allows the waxy wings
of desert beetles to become wettable by morning mist. Here, we show that a
sprinkle of graphene oxide nanoflakes (nanoGOs) is effective in condensing
water nanodroplets and seeding ice epitaxy on graphite at ambient conditions.
By controlling relative humidity and nanoGO density, we are able to study the
formation of a complete ice wetting layer on a time scale of 20 hours. This
presents an unprecedented opportunity to visualize ice nucleation and growth in
real time using non-contact atomic force microscopy. The stages of
crystallization, as proposed by Ostwald in 1897, is fully unfolded at a
microscopic level for the first time. We obtain real-time imaging of sequential
phase transition from amorphous ice to a transient cubic ice Ic stage and
finally to the stable hexagonal ice Ih. Most interestingly, we discover that
ice nucleation and growth can be influenced by modifying the functional groups
of nanoGO, and by intermolecular hydrogen-bonding between nanoGOs. This affords
a strategy to control heterogenous ice nucleation and snow crystal formation.


title: Error Rate Bounds in Crowdsourcing Models

abstract:
  Crowdsourcing is an effective tool for human-powered computation on many
tasks challenging for computers. In this paper, we provide finite-sample
exponential bounds on the error rate (in probability and in expectation) of
hyperplane binary labeling rules under the Dawid-Skene crowdsourcing model. The
bounds can be applied to analyze many common prediction methods, including the
majority voting and weighted majority voting. These bound results could be
useful for controlling the error rate and designing better algorithms. We show
that the oracle Maximum A Posterior (MAP) rule approximately optimizes our
upper bound on the mean error rate for any hyperplane binary labeling rule, and
propose a simple data-driven weighted majority voting (WMV) rule (called
one-step WMV) that attempts to approximate the oracle MAP and has a provable
theoretical guarantee on the error rate. Moreover, we use simulated and real
data to demonstrate that the data-driven EM-MAP rule is a good approximation to
the oracle MAP rule, and to demonstrate that the mean error rate of the
data-driven EM-MAP rule is also bounded by the mean error rate bound of the
oracle MAP rule with estimated parameters plugging into the bound.


title: Kondo effect in f-electron superlattices

abstract:
  We demonstrate the importance of the Kondo effect in artificially created
{\it f}-electron superlattices. We show that the Kondo effect does not only
change the density of states of the {\it f}-electron layers, but is also the
cause of pronounced resonances at the Fermi energy in the density of states of
the non-interacting layers in the superlattice, which are between the {\it
f}-electron layers. Remarkably, these resonances strongly depend on the
structure of the superlattice; due to interference, the density of states at
the Fermi energy can be strongly enhanced or even shows no changes at all.
Furthermore, we show that by inserting the Kondo lattice layer into a
three-dimensional (3D) metal, the gap of the Kondo insulating state changes
from a full gap to a pseudo gap with quadratically vanishing spectral weight
around the Fermi energy. Due to the formation of the Kondo insulating state in
the {\it f}-electron layer, the superlattice becomes strongly anisotropic below
the Kondo temperature. We prove this by calculating the in-plane and
out-of-plane conductivity of the superlattice.


title: Efficiency of Entanglement Concentration by Photon Subtraction

abstract:
  We introduce a measure of efficiency for the photon subtraction protocol
aimed at entanglement concentration on a single copy of bipartite continuous
variable state. We then show that iterating the protocol does not lead to
higher efficiency than a single application. In order to overcome this limit we
present an adaptive version of the protocol able to greatly enhance its
efficiency.


title:
All finitely generated Kleinian groups of small Hausdorff dimension are
  classical Schottky groups

abstract:
  This is the second part of the works on Hausdorff dimensions of Schottky
groups. It has been conjectured that the Hausdorff dimensions of nonclassical
Schottky groups are strictly bounded from below. In this second part of our
works we provide a resolution of this conjecture, we prove that there exists a
universal positive number $\lambda>0$, such that any finitely-generated
non-elementary Kleinian groups with limit set of Hausdorff dimension $<\lambda$
are classical Schottky groups. We will generalize our previous technologies
given in \cite{HS} to prove our general result. Our result can be consider as a
converse to \cite{Doyle}.


title:
Dependence of Residual Rotation Measure (RRM) on Intervening MgII
  Absorbers at Cosmic Distances

abstract:
  We investigate the dependence of residual rotation measure (RRM) on
intervening absorption systems at cosmic distances by using a large sample of
539 SDSS quasars in conjunction with the available rotation measure catalog at
around 21cm wavelength. We found an excess extragalactic contribution in
standard deviation of observed RRM of about 8.11+/-4.83 Rad/m^2 in our sample
with intervening MgII absorber as compare to the sample without MgII absorber.
Our results suggest that intervening absorbers could contribute to the
enhancement of RRM at around 21cm wavelength, as was found earlier for RM
measurements at around 6cm wavelength.


title:
Convergence of an iterative algorithm for Teichm\"uller maps via
  generalized harmonic maps

abstract:
  Finding surface mappings with least distortion arises from many applications
in various fields. Extremal Teichm\"uller maps are surface mappings with least
conformality distortion. The existence and uniqueness of the extremal
Teichm\"uller map between Riemann surfaces of finite type are theoretically
guaranteed [1]. Recently, a simple iterative algorithm for computing the
Teichm\"uller maps between connected Riemann surfaces with given boundary
value was proposed in [11]. Numerical results was reported in the paper to show
the effectiveness of the algorithm. The method was successfully applied to
landmark-matching registration. The purpose of this paper is to prove the
iterative algorithm proposed in [11] indeed converges.


title:
The Contrastive analysis of observation data between HLS and DSQ water
  tube clinometers in Jingxian seismicstation

abstract:
  A set of HLS was installed in JingXian seismicstation for the tidal
correction of observations from HLS. Harmonic analysis of the data recorded by
HLS and DSQ water tube clinometers in JingXian seismicstation and contrastive
analysis of the results are completed. The tilt tide can be well reflected in
the data of the both instruments and the results are both reliable. The reasons
of the difference between the results are analyzed. The tilt tidal factor is
related with with the type of observation instruments with different damping
constant. Besides, the relations between the frequency response of the
instrument and the tidal factor are discussed in this paper. The current
research establishs a foundation for HLS to be applied in micron-level
precision alignment of particle accelerator in the future.


title: Electrically Modulated Wetting of Drops on Soft Dielectric Films

abstract:
  The inter-connection between the elasticity of a dielectric film and the
wetting of a sessile drop on the same, under an applied electrical voltage,
remains unaddressed. Here, we report the electrowetting-on-dielectric (EWOD)
behaviour of sessile drops on dielectric elastomer films of varying
elasticities- from an apparently rigid dielectric film to a soft, deformable
dielectric film. Our results reveal that the elasticity of the underlying
dielectric film provides an additional control over the droplet electrowetting
behaviour, which may be best addressed from free energy based consideration,
leading to a modification of the classical Lippman-Young paradigm. We also
provide an explanation on the displacement profiles for the deformation of the
soft dielectric surface, due to the interfacial electro-elastocapillary
interaction triggered by the electrowetted sessile droplet. These results can
be of profound importance in various emerging applications, ranging from the
development of soft liquid lenses to drug delivery.


title:
Non-axisymmetric vertical shear and convective instabilities as a
  mechanism of angular momentum transport

abstract:
  Discs with a rotation profile depending on radius and height are subject to
an axisymmetric linear instability, the vertical shear instability. Here we
show that non-axisymmetric perturbations, while eventually stabilized, can
sustain huge exponential amplifications with growth rate close to the
axisymmetric one. Transient growths are therefore to all effects genuine
instabilities. The ensuing angular momentum transport is positive. These
growths occur when the product of the radial times the vertical wavenumbers
(both evolving with time) is positive for a positive local vertical shear, or
negative for a negative local vertical shear.
  We studied, as well, the interaction of these vertical shear induced growths
with a convective instability. The asymptotic behaviour depends on the relative
strength of the axisymmetric vertical shear (s_v) and convective (s_c) growth
rates. For s_v > s_c we observed the same type of behaviour described above -
large growths occur with asymptotic stabilization. When s_c > s_v the system is
asymptotically unstable, with a growth rate which can be slightly enhanced with
respect to s_c. The most interesting feature is the sign of the angular
momentum transport. This is always positive in the phase in which the vertical
shear driven transients growths occur, even in the case s_c > s_v . Thermal
diffusion has a stabilizing influence on the convective instability, specially
for short wavelengths.


title: Metrology with entangled coherent states - a quantum scaling paradox

abstract:
  There has been much interest in developing phase estimation schemes which
beat the so-called Heisenberg limit, i.e., for which the phase resolution
scales better than 1/n, where n is a measure of resources such as the average
photon number or the number of atomic qubits. In particular, a number of
nonlinear schemes have been proposed for which the resolution appears to scale
as 1/n^k or even exp(-n), based on optimising the quantum Cramer-Rao bound.
Such schemes include the use of entangled coherent states. However, it may be
shown that the average root mean square errors of the proposed schemes
(averaged over any prior distribution of phase shifts), cannot beat the
Heisenberg limit, and that simple estimation schemes based on entangled
coherent states cannot scale better than 1/n^{1/4}. This paradox is related to
the role of 'bias' in Cramer-Rao bounds, and is only partially ameliorated via
iterative implementations of the proposed schemes. The results are based on new
information-theoretic bounds for the average information gain and error of any
phase estimation scheme, and generalise to estimates of shifts generated by any
operator having discrete eigenvalues.


title: The threshold for collapsibility in random complexes

abstract:
  In this paper we determine the threshold for collapsibility in the
probabilistic model $X_d(n,p)$ of $d$-dimensional simplicial complexes. A lower
bound for this threshold $p=\frac{c_d}{n}$ was established in \cite{ALLM}. Here
we show that this is indeed the correct threshold. Namely, for every $c>c_d$, a
complex drawn from $X_d(n,\frac{c}{n})$ is asymptotically almost surely not
collapsible.


title: Gaussian field theory for the Brownian motion of a solvated particle

abstract:
  An alternative derivation of Brownian motion is presented. Instead of
supplementing the linearized Navier-Stokes equation with a fluctuating force,
we directly assume a Gaussian action functional for solvent velocity
fluctuations. Solvating a particle amounts to expelling the solvent and
prescribing a boundary condition to the solvent on the interface that is shared
with the solute. We study the dynamical effects of this boundary condition on
the solvent and derive explicit expressions for the solvent mean flow and
velocity correlations. Moreover, we show that the probability to observe
solvent velocity fluctuations that are compatible with the boundary condition
reproduces random Brownian motion of the solvated particle. We explicitly
calculate the translational and rotational diffusion coefficients of a
spherical particle using the presented formalism.


title: Gauss-Markov processes on Hilbert spaces

abstract:
  K. It\^{o} characterised in \cite{ito} zero-mean stationary Gauss
Markov-processes evolving on a class of infinite-dimensional spaces. In this
work we extend the work of It\^{o} in the case of Hilbert spaces: Gauss-Markov
families that are time-homogenous are identified as solutions to linear
stochastic differential equations with singular coefficients. Choosing an
appropriate locally convex topology on the space of weakly sequentially
continuous functions we also characterize the transition semigroup, the
generator and its core thus providing an infinite-dimensional extension of the
classical result of Courr\`ege \cite{courrege} in the case of Gauss-Markov
semigroups.


title: Studies on some singular potentials in quantum mechanics

abstract:
  A simple methodology is suggested for the efficient calculation of certain
central potentials having singularities. The generalized pseudospectral method
used in this work facilitates {\em nonuniform} and optimal spatial
discretization. Applications have been made to calculate the energies,
densities and expectation values for two singular potentials of physical
interest, {\em viz.,} (i) the harmonic potential plus inverse quartic and
sextic perturbation and (ii) the Coulomb potential with a linear and quadratic
term for a broad range of parameters. The first 10 states belonging to a
maximum of $\ell=8$ and 5 for (i) and (ii) have been computed with good
accuracy and compared with the most accurate available literature data. The
calculated results are in excellent agreement, especially in the light of the
difficulties encountered in these potentials. Some new states are reported here
for the first time. This offers a general and efficient scheme for calculating
these and other similar potentials of physical and mathematical interest in
quantum mechanics accurately.


title: Multicoloring of cannonball graphs

abstract:
  The frequency allocation problem that appeared in the design of cellular
telephone networks can be regarded as a multicoloring problem on a weighted
hexagonal graph, which opened some still interesting mathematical problems. We
generalize the multicoloring problem into higher dimension and present the
first \jz{approximation} algorithms for multicoloring of so called cannonball
graphs.


title: Steinberg groups as amalgams

abstract:
  For any root system and any commutative ring we give a relatively simple
presentation of a group related to its Steinberg group St. This includes the
case of infinite root systems used in Kac-Moody theory, for which the Steinberg
group was defined by Tits and Morita-Rehmann. In most cases our group equals
St, giving a presentation with many advantages over the usual presentation of
St. This equality holds for all spherical root systems, all irreducible affine
root systems of rank>2, and all 3-spherical root systems. When the coefficient
ring satisfies a minor condition, the last condition can be relaxed to
2-sphericity.
  Our presentation is defined in terms of the Dynkin diagram rather than the
full root system. It is concrete, with no implicit coefficients or signs. It
makes manifest the exceptional diagram automorphisms in characteristics 2 and
3, and their generalizations to Kac-Moody groups. And it is a Curtis-Tits style
presentation: it is the direct limit of the groups coming from 1- and 2-node
subdiagrams of the Dynkin diagram. Over non-fields this description as a direct
limit is new and surprising. Our main application is that many Steinberg and
Kac-Moody groups over finitely-generated rings are finitely presented.


title: BGP Security in Partial Deployment: Is the Juice Worth the Squeeze?

abstract:
  As the rollout of secure route origin authentication with the RPKI slowly
gains traction among network operators, there is a push to standardize secure
path validation for BGP (i.e., S*BGP: S-BGP, soBGP, BGPSEC, etc.). Origin
authentication already does much to improve routing security. Moreover, the
transition to S*BGP is expected to be long and slow, with S*BGP coexisting in
"partial deployment" alongside BGP for a long time. We therefore use
theoretical and experimental approach to study the security benefits provided
by partially-deployed S*BGP, vis-a-vis those already provided by origin
authentication. Because routing policies have a profound impact on routing
security, we use a survey of 100 network operators to find the policies that
are likely to be most popular during partial S*BGP deployment. We find that
S*BGP provides only meagre benefits over origin authentication when these
popular policies are used. We also study the security benefits of other routing
policies, provide prescriptive guidelines for partially-deployed S*BGP, and
show how interactions between S*BGP and BGP can introduce new vulnerabilities
into the routing system.


title:
Singularity Structure of N=2 Supersymmetric Yang-Mills Theories: A
  Review

abstract:
  In this review, we consider the case where electrons, magnetic monopoles, and
dyons become massless. Here we consider the ${\cal N} = 2$ supersymmetric
Yang-Mills (SYM) theories with classical gauge groups with a rank r, SU(r+1),
SO(2r), Sp(2r), and SO(2r+1). which are studied by Riemann surfaces called
Seiberg-Witten curves. We discuss physical singularity associated with massless
particles, which can be studied by geometric singularity of vanishing 1-cycles
in Riemann surfaces in hyperelliptic form. We pay particular attention to the
cases where mutually non-local states become massless (Argyres-Douglas
theories), which corresponds to Riemann surfaces degenerating into cusps. We
discuss non-trivial topology on the moduli space of the theory, which is
reflected as monodromy associated to vanishing 1-cycles. We observe how dyon
charges get changed as we move around and through singularity in moduli space.


title: Charge ordering transition in GdBaCo2O5: evidence of reentrant behavior

abstract:
  We present a detailed study on the charge ordering (CO) transition in
GdBaCo2O5 system by combining high resolution synchrotron powder/single crystal
diffraction with electron paramagnetic resonance (EPR) experiments as a
function of temperature. We found a second order structural phase transition at
TCO=247 K (Pmmm to Pmma) associated with the onset of long range CO. At Tmin =
1.2TCO, the EPR linewidth rapidly broadens providing evidence of spin
fluctuations due to magnetic interactions between Gd3+ ions and
antiferromagnetic couplings of Co2+/Co3+ sublattices. This likely indicates
that, analogously to manganites, the long-range antiferromagnetic order in
GdBaCo2O5 sets in at TCO. Pair distribution function (PDF) analysis of
diffraction data revealed signatures of structural inhomogeneities at low
temperature. By comparing the average and local bond valences, we found that
above TCO the local structure is consistent with a fully random occupation of
Co2+ and Co3+ in a 1:1 ratio and with a complete charge ordering below TCO.
Below T = 100 K the charge localization is partially melted at the local scale,
suggesting a reentrant behavior of CO. This result is supported by the
weakening of superstructure reflections and the temperature evolution of EPR
linewidth that is consistent with paramagnetic (PM) reentrant behavior reported
in the GdBaCo2O5.5 parent compound.


title:
Doping a correlated band insulator: A new route to half metallic
  behaviour

abstract:
  We demonstrate in a simple model the surprising result that turning on an
on-site Coulomb interaction U in a doped band insulator leads to the formation
of a half-metallic state. In the undoped system, we show that increasing U
leads to a first order transition between a paramagnetic, band insulator and an
antiferomagnetic Mott insulator at a finite value U_{AF}. Upon doping, the
system exhibits half metallic ferrimagnetism over a wide range of doping and
interaction strengths on either side of U_{AF}. Our results, based on dynamical
mean field theory, suggest a novel route to half-metallic behavior and provide
motivation for experiments on new materials for spintronics.


title: Scalar Spin of Elementary Fermions

abstract:
  We show that, using the experimentally observed values of CKM and PMNS mixing
matrices, all known elementary fermions can be assigned a new quantum number,
the scalar spin, in a unique way. This is achieved without introduction of new
degrees of freedom. The assignment implies that tau-neutrino should be an
anti-Dirac spinor, while mu-tau leptons and charm-top, strange-bottom quarks
form Dirac-anti-Dirac scalar spin doublets. The electron and its neutrino
remain as originally described by Dirac.


title: PT Symmetry via Electromagnetically Induced Transparency

abstract:
  We propose a scheme to realize parity-time (PT) symmetry via
electromagnetically induced transparency (EIT). The system we consider is an
ensemble of cold four-level atoms with an EIT core. We show that the
cross-phase modulation contributed by an assisted field, the optical lattice
potential provided by a far-detuned laser field, and the optical gain resulted
from an incoherent pumping can be used to construct a PT-symmetric complex
optical potential for probe field propagation in a controllable way. Comparing
with previous study, the present scheme uses only a single atomic species and
hence is easy for the physical realization of PT-symmetric Hamiltonian via
atomic coherence.


title:
Ranking on Arbitrary Graphs: Rematch via Continuous LP with Monotone and
  Boundary Condition Constraints

abstract:
  Motivated by online advertisement and exchange settings, greedy randomized
algorithms for the maximum matching problem have been studied, in which the
algorithm makes (random) decisions that are essentially oblivious to the input
graph. Any greedy algorithm can achieve performance ratio 0.5, which is the
expected number of matched nodes to the number of nodes in a maximum matching.
  Since Aronson, Dyer, Frieze and Suen proved that the Modified Randomized
Greedy (MRG) algorithm achieves performance ratio 0.5 + \epsilon (where
\epsilon = frac{1}{400000}) on arbitrary graphs in the mid-nineties, no further
attempts in the literature have been made to improve this theoretical ratio for
arbitrary graphs until two papers were published in FOCS 2012. Poloczek and
Szegedy also analyzed the MRG algorithm to give ratio 0.5039, while Goel and
Tripathi used experimental techniques to analyze the Ranking algorithm to give
ratio 0.56. However, we could not reproduce the experimental results of Goel
and Tripathi.
  In this paper, we revisit the Ranking algorithm using the LP framework.
Special care is given to analyze the structural properties of the Ranking
algorithm in order to derive the LP constraints, of which one known as the
\emph{boundary} constraint requires totally new analysis and is crucial to the
success of our LP.
  We use continuous LP relaxation to analyze the limiting behavior as the
finite LP grows. Of particular interest are new duality and complementary
slackness characterizations that can handle the monotone and the boundary
constraints in continuous LP. We believe our work achieves the currently best
theoretical performance ratio of \frac{2(5-\sqrt{7})}{9} \approx 0.523 on
arbitrary graphs. Moreover, experiments suggest that Ranking cannot perform
better than 0.724 in general.


title: Correlation Distance and Bounds for Mutual Information

abstract:
  The correlation distance quantifies the statistical independence of two
classical or quantum systems, via the distance from their joint state to the
product of the marginal states. Tight lower bounds are given for the mutual
information between pairs of two-valued classical variables and quantum qubits,
in terms of the corresponding classical and quantum correlation distances.
These bounds are stronger than the Pinsker inequality (and refinements thereof)
for relative entropy. The classical lower bound may be used to quantify
properties of statistical models that violate Bell inequalities. Entangled
qubits can have a lower mutual information than can any two-valued classical
variables having the same correlation distance. The qubit correlation distance
also provides a direct entanglement criterion, related to the spin covariance
matrix. Connections of results with classically-correlated quantum states are
briefly discussed.


title:
Absence of helical surface states in bulk semimetals with broken
  inversion symmetry

abstract:
  Whereas the concept of topological band-structures was developed originally
for insulators with a bulk bandgap, it has become increasingly clear that the
prime consequences of a non-trivial topology -- spin-momentum locking of
surface states -- can also be encountered in gapless systems. Concentrating on
the paradigmatic example of mercury chalcogenides HgX (X = Te, Se, S), we show
that the existence of helical semimetals, i.e. semimetals with topological
surface states, critically depends on the presence of crystal inversion
symmetry. An infinitesimally small broken inversion symmetry (BIS) renders the
helical semimetallic state unstable. The BIS is also very important in the
fully gapped regime, renormalizing the surface Dirac cones in an anisotropic
manner. As a consequence the handedness of the Dirac cones can be flipped by a
biaxial stress field.


title: From Classical to Quantum Glasses with Ultracold Polar Molecules

abstract:
  The dynamics of a bilayer system of ultracold dipolar molecules exhibits
classical and quantum glassy behavior, characterized by long tails in the
relaxation time and dynamical heterogeneity. In the proposed setup, quantum
fluctuations are of the order of thermal fluctuations and the degree of
frustration can tuned by the interlayer distance. We present experimental
accessible order parameters based on marker molecules, distinguished by
properly chosen internal levels, and find quantum features of dynamical
heterogeneity.


title:
Kinetic Data Structures for the Semi-Yao Graph and All Nearest Neighbors
  in R^d

abstract:
  This paper presents a simple kinetic data structure for maintaining all the
nearest neighbors of a set of $n$ moving points in $\mathbb{R}^d$, where the
trajectory of each point is an algebraic function of at most constant degree
$s$. The approach is based on maintaining the edges of the Semi-Yao graph, a
sparse graph whose edge set includes the pairs of nearest neighbors as a
subset.
  Our kinetic data structure (KDS) for maintaining all the nearest neighbors is
deterministic. It processes $O(n^2\beta_{2s+2}^2(n)\log n)$ events with a total
cost of $O(n^2\beta_{2s+2}(n)\log^{d+1} n)$. Here, $\beta_s(n)$ is an extremely
slow-growing function. The best previous KDS for all the nearest neighbors in $
\mathbb{R}^d$ is by Agarwal, Kaplan, and Sharir (TALG 2008). It is a randomized
result. Our structure and analysis are simpler than theirs. Also, we improve
their result by a factor of $\log^d n$ in the number of events and by a $\log
n$ factor in the total cost.
  This paper generalizes and improves the 2013 work of Rahmati, King and
Whitesides (SoCG 2013) on maintaining the Semi-Yao graph in $\mathbb{R}^2$; its
new technique provides the first KDS for the Semi-Yao graph in $\mathbb{R}^d$.
Our KDS is local in the worst case, meaning that only a constant number of
events is associated with any one point at any time.
  For maintaining all the nearest neighbors, neither our KDS nor the KDS by
Agarwal~\etal~is local, and furthermore, each event in our KDS and in their KDS
is handled in polylogarithmic time in an amortized sense.
  Finally, in this paper, we also give a KDS for maintenance of all the
$(1+\epsilon)$-nearest neighbors which is local and each event can be handled
in a polylogarithmic worst-case time.


title: Coherence Factors Beyond the BCS Result

abstract:
  The dynamics of BCS (Bardeen-Cooper-Schrieffer) superconductors is fairly
well understood due to the availability of a mean field solution for the
pairing Hamiltonian, a solution which gives the quantum state of superconductor
as a state of almost-free fermions interacting only with a condensate. As a
result, transition probabilities may be computed, and expressed in terms of
matrix elements of electron creation and annihilation operators between
approximate eigenstates. These matrix elements are also called 'coherent
factors'. Mean-field theory is however not sufficient to describe all
eigenstates of a superconductor, a deficiency which is hardly important in (or
very close) to equilibrium, but one that becomes relevant in certain out of
equilibrium situations. We report here on a computation of matrix elements
(coherence factors) for the pairing Hamiltonian between any 'two-arc'
eigenstates in the thermodynamic limit.


title: Modular generalized Springer correspondence I: the general linear group

abstract:
  We define a generalized Springer correspondence for the group GL(n) over any
field. We also determine the cuspidal pairs, and compute the correspondence
explicitly. Finally we define a stratification of the category of equivariant
perverse sheaves on the nilpotent cone of GL(n) satisfying the `recollement'
properties, and with subquotients equivalent to categories of representations
of a product of symmetric groups.


title:
Topological aspects in the photonic crystal analog of single-particle
  transport in quantum Hall systems

abstract:
  We present a perturbative approach to derive the semiclassical equations of
motion for the two-dimensional electron dynamics under the simultaneous
presence of static electric and magnetic fields, where the quantized Hall
conductance is known to be directly related to the topological properties of
translationally invariant magnetic Bloch bands. In close analogy to this
approach, we develop a perturbative theory of two-dimensional photonic
transport in gyrotropic photonic crystals to mimic the physics of quantum Hall
systems. We show that a suitable permittivity grading of a gyrotropic photonic
crystal is able to simulate the simultaneous presence of analog electric and
magnetic field forces for photons, and we rigorously derive the
topology-related term in the equation for the electromagnetic energy velocity
that is formally equivalent to the electronic case. A possible experimental
configuration is proposed to observe a bulk photonic analog to the quantum Hall
physics in graded gyromagnetic photonic crystals.


title: Applications of repeat degree on coverings of neighborhoods

abstract:
  In covering based rough sets, the neighborhood of an element is the
intersection of all the covering blocks containing the element. All the
neighborhoods form a new covering called a covering of neighborhoods. In the
course of studying under what condition a covering of neighborhoods is a
partition, the concept of repeat degree is proposed, with the help of which the
issue is addressed. This paper studies further the application of repeat degree
on coverings of neighborhoods. First, we investigate under what condition a
covering of neighborhoods is the reduct of the covering inducing it. As a
preparation for addressing this issue, we give a necessary and sufficient
condition for a subset of a set family to be the reduct of the set family. Then
we study under what condition two coverings induce a same relation and a same
covering of neighborhoods. Finally, we give the method of calculating the
covering according to repeat degree.


title: Making Octants Colorful and Related Covering Decomposition Problems

abstract:
  We give new positive results on the long-standing open problem of geometric
covering decomposition for homothetic polygons. In particular, we prove that
for any positive integer k, every finite set of points in R^3 can be colored
with k colors so that every translate of the negative octant containing at
least k^6 points contains at least one of each color. The best previously known
bound was doubly exponential in k. This yields, among other corollaries, the
first polynomial bound for the decomposability of multiple coverings by
homothetic triangles. We also investigate related decomposition problems
involving intervals appearing on a line. We prove that no algorithm can
dynamically maintain a decomposition of a multiple covering by intervals under
insertion of new intervals, even in a semi-online model, in which some coloring
decisions can be delayed. This implies that a wide range of sweeping plane
algorithms cannot guarantee any bound even for special cases of the octant
problem.


title:
Electric dipole response of 208Pb from proton inelastic scattering:
  constraints on neutron skin thickness and symmetry energy

abstract:
  The electric dipole (E1) response of 208Pb has been precisely determined by
measuring Coulomb excitation induced by proton scattering at very forward
angles. The electric dipole polarizability, defined as inverse energy-weighted
sum rule of the E1 strength, has been extracted as 20.1+-0.6 fm^3. The data can
be used to constrain the neutron skin thickness of 208Pb to
0.168(+-0.009)_expt(+-0.013)_theo(+-0.021)_est fm, where the subscript "expt"
refers to the experimental uncertainty, "theor" to the theoretical confidence
band and "est" to the uncertainty associated with the estimation of the
symmetry energy at the saturation density. In addition, a constraint band has
been extracted in the plane of the symmetry energy (J) and its slope parameter
(L) at the saturation density.


title: Minimal Castelnuovo-Mumford regularity for a given Hilbert polynomial

abstract:
  Let $K$ be an algebraically closed field of null characteristic and $p(z)$ a
Hilbert polynomial. We look for the minimal Castelnuovo-Mumford regularity
$m_{p(z)}$ of closed subschemes of projective spaces over $K$ with Hilbert
polynomial $p(z)$. Experimental evidences led us to consider the idea that
$m_{p(z)}$ could be achieved by schemes having a suitable minimal Hilbert
function. We give a constructive proof of this fact. Moreover, we are able to
compute the minimal Castelnuovo-Mumford regularity $m_p(z)^{\varrho}$ of
schemes with Hilbert polynomial $p(z)$ and given regularity $\varrho$ of the
Hilbert function, and also the minimal Castelnuovo-Mumford regularity $m_u$ of
schemes with Hilbert function $u$. These results find applications in the study
of Hilbert schemes. They are obtained by means of minimal Hilbert functions and
of two new constructive methods which are based on the notion of
growth-height-lexicographic Borel set and called ideal graft and extended
lifting.


title: Unique expansion matroids and union minimal matroids

abstract:
  The expansion axiom of matroids requires only the existence of some kind of
independent sets, not the uniqueness of them. This causes that the base
families of some matroids can be reduced while the unions of the base families
of these matroids remain unchanged. In this paper, we define unique expansion
matroids in which the expansion axiom has some extent uniqueness; we define
union minimal matroids in which the base families have some extent minimality.
Some properties of them and the relationship between them are studied. First,
we propose the concepts of secondary base and forming base family. Secondly, we
propose the concept of unique expansion matroid, and prove that a matroid is a
unique expansion matroid if and only if its forming base family is a partition.
Thirdly, we propose the concept of union minimal matroid, and prove that unique
expansion matroids are union minimal matroids. Finally, we extend the concept
of unique expansion matroid to unique exchange matroid and prove that both
unique expansion matroids and their dual matroids are unique exchange matroids.


title:
Photodetachment as destruction mechanism for CN- and C3N- anions in
  circumstellar envelopes

abstract:
  Absolute photodetachment cross sections of two anions of astrophysical
importance CN- and C3N- were measured to be (1.18 +- (0.03)_stat (0.17)_sys) *
10^-17 cm^2 and (1.43 +- (0.14)_stat (0.37)_sys) * 10^-17 cm^2 respectively at
the ultraviolet wavelength of 266 nm (4.66 eV). These relatively large values
of the cross sections imply that photodetachment can play a major role in the
destruction mechanisms of these anions particularly in photon-dominated
regions. We have therefore carried out model calculations using the newly
measured cross sections to investigate the abundance of these molecular anions
in the cirumstellar envelope of the carbon-rich star IRC+10216. The model
predicts the relative importance of the various mechanisms of formation and
destruction of these species in different regions of the envelope. UV
photodetachment was found to be the major destruction mechanism for both CN-
and C3N- anions in those regions of the envelope, where they occur in peak
abundance. It was also found that photodetachment plays a crucial role in the
degradation of these anions throughout the circumstellar envelope.


title: Torsion-free $G_{2(2)}^*$-structures with full holonomy on nilmanifolds

abstract:
  We study the existence of invariant metrics with holonomy $G_{2(2)}^* \subset
SO(4,3)$ on compact nilmanifolds, i.e. on compact quotients of nilpotent Lie
groups by discrete subgroups. We prove that, up to isomorphism, there exists
only one indecomposable nilpotent Lie algebra admitting a torsion-free
$G_{2(2)}^*$-structure such that the center is definite with respect to the
induced inner product. In particular, we show that the associated compact
nilmanifold admits a 3-parameter family of invariant metrics with full holonomy
$G_{2(2)}^*$.


title:
Transmission properties of one dimensional metal and left-handed
  gratings

abstract:
  We provide rigorous numerical calculations (using the rigorous coupled-wave
analysis) of transmission spectra of various metallic and metamaterial
one-dimensional gratings and identify plasmonic resonances responsible for
enhanced transmission. We argue that the most important mechanism which
influences the resonant transmission is the coupling of incident
electromagnetic wave with two plasmonic waves: lengthwise plasmons, which
propagates along the grating, and crosswise plasmons excited in air gaps.


title: On cluster points of alternating projections

abstract:
  Suppose that $A$ and $B$ are closed subsets of a Euclidean space such that
$A\cap B\neq\varnothing$, and we aim to find a point in this intersection with
the help of the sequences $(a_n)_\nnn$ and $(b_n)_\nnn$ generated by the
\emph{method of alternating projections}. It is well known that if $A$ and $B$
are convex, then $(a_n)_\nnn$ and $(b_n)_\nnn$ converge to some point in $A\cap
B$. The situation in the nonconvex case is much more delicate. In 1990,
Combettes and Trussell presented a dichotomy result that guarantees either
convergence to a point in the intersection or a nondegenerate compact continuum
as the set of cluster points.
  In this note, we construct two sets in the Euclidean plane illustrating the
continuum case. The sets $A$ and $B$ can be chosen as countably infinite unions
of closed convex sets. In contrast, we also show that such behaviour is
impossible for finite unions.


title: Capturing Hiproofs in HOL Light

abstract:
  Hierarchical proof trees (hiproofs for short) add structure to ordinary proof
trees, by allowing portions of trees to be hierarchically nested. The
additional structure can be used to abstract away from details, or to label
particular portions to explain their purpose. In this paper we present two
complementary methods for capturing hiproofs in HOL Light, along with a tool to
produce web-based visualisations. The first method uses tactic recording, by
modifying tactics to record their arguments and construct a hierarchical tree;
this allows a tactic proof script to be modified. The second method uses proof
recording, which extends the HOL Light kernel to record hierachical proof trees
alongside theorems. This method is less invasive, but requires care to manage
the size of the recorded objects. We have implemented both methods, resulting
in two systems: Tactician and HipCam.


title: The Properties of Bertrand Curves In Dual Space

abstract:
  In this study, we investigate Bertrand curves in three dimensional dual space
D3 and we obtain the characterizations of these curves in dual space D3. Also
we show that involutes of a curve constitute Bertrand pair curves.


title:
Optimisation dans la d\'etection de communaut\'es recouvrantes et
  \'equilibre de Nash

abstract:
  Community detection in graphs has been the subject of many algorithms. Recent
methods want to optimize a modularity function which shows a maximum of
relationships within communities and found a minimum of inter-community
relations. these algorithms are applied to unipartite, multipartite and
directed graphs. However, given the NP-completeness of the problem, these
algorithms are heuristics that do not guarantee an optimum. In this paper we
introduce an algorithm which, based on an approximate solution obtained through
a efficient detection algorithm, modifie it to achieve a local optimum based on
a function. this reassignment function is a potential function and therefore
the computed optimum is a Nash equilibrium. We supplement our method with an
overlap function that allows to have simultaneously the two detection modes.
Several experiments show the interest of our approach.


title: Ruled Weingarten Surfaces Related to Dual Spherical Curves

abstract:
  We study ruled surfaces in R3 which are obtained from dual spher- ical
indicatrix curves of dual Frenet vector fields. We find the Gaussian and mean
curvatures of the ruled surfaces and give some results of being Wein- garten
surface.


title: Reliable SPICE Simulations of Memristors, Memcapacitors and Meminductors

abstract:
  Memory circuit elements, namely memristive, memcapacitive and meminductive
systems, are gaining considerable attention due to their ubiquity and use in
diverse areas of science and technology. Their modeling within the most widely
used environment, SPICE, is thus critical to make substantial progress in the
design and analysis of complex circuits. Here, we present a collection of
models of different memory circuit elements and provide a methodology for their
accurate and reliable modeling in the SPICE environment. We also provide codes
of these models written in the most popular SPICE versions (PSpice, LTspice,
HSPICE) for the benefit of the reader. We expect this to be of great value to
the growing community of scientists interested in the wide range of
applications of memory circuit elements.


title: Functional Graphs of Polynomials over Finite Fields

abstract:
  Given a function $f$ in a finite field ${\mathbb F}_q$ of $q$ elements, we
define the functional graph of $f$ as a directed graph on $q$ nodes labelled by
the elements of ${\mathbb F}_q$ where there is an edge from $u$ to $v$ if and
only if $f(u) = v$. We obtain some theoretic estimates on the number of
non-isomorphic graphs generated by all polynomials of a given degree. We then
develop a simple and practical algorithm to test the isomorphism of quadratic
polynomials that has linear memory and time complexities. Furthermore, we
extend this isomorphism testing algorithm to the general case of functional
graphs, and prove that, while its time complexity increases only slightly, its
memory complexity remains linear. We exploit this algorithm to provide an upper
bound on the number of functional graphs corresponding to polynomials of degree
$d$ over ${\mathbb F}_q$. Finally, we present some numerical results and
compare function graphs of quadratic polynomials with those generated by random
maps and pose interesting new problems.


title: Deformations of Polyhedra and Polygons by the Unitary Group

abstract:
  We introduce the set of framed convex polyhedra with N faces as the
symplectic quotient C^2N//SU(2). A framed polyhedron is then parametrized by N
spinors living in C^2 satisfying suitable closure constraints and defines a
usual convex polyhedron plus a phase for each face. We show that there is an
action of the unitary group U(N) on this phase space, which changes the shape
of faces and allows to map any polyhedron onto any other with the same total
area. This realizes the isomorphism of the space of framed polyhedra with the
Grassmannian space U(N)/SU(2)*U(N-2). We show how to write averages and
correlations of geometrical observables over the ensemble of polyhedra as
polynomial integrals over U(N) and we use the Itzykson-Zuber formula from
matrix models as the generating function for them. In the quantum case, a
canonical quantization of the framed polyhedron phase space leads to the
Hilbert space of SU(2) intertwiners. The individual face areas are quantized as
half-integers (spins) and the Hilbert spaces for fixed total area form
irreducible representations of U(N). We define coherent intertwiner states
peaked on classical framed polyhedra and transforming consistently under U(N)
transformations. The U(N) character formula can be considered as an extension
of the Itzykson-Zuber to the quantum level and generates the traces of all
polynomial observables over the Hilbert space of intertwiners. We finally show
that classical (convex) polygons can be described in a similar fashion trading
U(N) for O(N). We conclude with a discussion of the possible (deformation)
dynamics that one can define on the space of polygons or polyhedra. This work
is a priori useful in the context of discrete geometry but it should also be
relevant to (loop) quantum gravity in 2+1 and 3+1 dimensions when the quantum
geometry is defined in terms of gluing of (quantized) polygons and polyhedra.


title: The Helix Relation Between Two Curves

abstract:
  In this study, we give the relation of being general helix and slant helix of
two curves by using the equation between them. Also we find some results and
express the characterizations of these curves.


title: SN 2011fe: A Laboratory for Testing Models of Type Ia Supernovae

abstract:
  SN 2011fe is the nearest supernova of Type Ia (SN Ia) discovered in the
modern multi-wavelength telescope era, and it also represents the earliest
discovery of a SN Ia to date. As a normal SN Ia, SN 2011fe provides an
excellent opportunity to decipher long-standing puzzles about the nature of SNe
Ia. In this review, we summarize the extensive suite of panchromatic data on SN
2011fe, and gather interpretations of these data to answer four key questions:
1) What explodes in a SN Ia? 2) How does it explode? 3) What is the progenitor
of SN 2011fe? and 4) How accurate are SNe Ia as standardizeable candles? Most
aspects of SN 2011fe are consistent with the canonical picture of a massive CO
white dwarf undergoing a deflagration-to-detonation transition. However, there
is minimal evidence for a non-degenerate companion star, so SN 2011fe may have
marked the merger of two white dwarfs.


title:
An overlooked brown dwarf neighbour (T7.5 at d~5pc) of the Sun and two
  additional T dwarfs at about 10pc

abstract:
  Although many new brown dwarf (BD) neighbours have recently been discovered
thanks to new sky surveys in the mid- and near-infrared (MIR, NIR), their
numbers are still more than five times lower than those of stars in the same
volume. Our aim is to detect and classify new BDs to eventually complete their
census in the immediate Solar neighbourhood. We combined multi-epoch data from
sky surveys at different wavelengths to detect BD neighbours of the Sun by
their high proper motion (HPM). We concentrated at relatively bright MIR
(w2<13.5) BD candidates from WISE expected to be so close to the Sun that they
may also be seen in older NIR (2MASS, DENIS) or even red optical (SDSS i- and
z-band, SSS I-band) surveys. With low-resolution NIR spectroscopy we classified
the new BDs and estimated their distances and velocities. We have discovered
the HPM (pm~470mas/yr) T7.5 dwarf, WISE J0521+1025, which is at d=5.0+-1.3pc
from the Sun the nearest known T dwarf in the northern sky, and two early-T
dwarfs, WISE J0457-0207 (T2) and WISE J2030+0749 (T1.5), with proper motions of
~120 and ~670mas/yr and distances of 12.5+-3.1pc and 10.5+-2.6pc, respectively.
The last one was independently discovered and also classified as a T1.5 dwarf
by Mace and coworkers. All three show thin disk kinematics. They may have been
overlooked in the past owing to overlapping images and because of problems with
matching objects between different surveys and measuring their proper motions.


title:
The Photodetector Plane of the 4m Davies Cotton Small Size Telescope for
  the Cherenkov Telescope Array

abstract:
  Photomultipliers (PMTs) are currently adopted for the photodetector plane of
Imaging Atmospheric Cherenkov Telescopes (IACTs). Even though PMT quantum
efficiency has improved impressively in the recent years, one of the main
limitation for their application in the gamma-astronomy field - the
impossibility to operate with moon light - still remains. As a matter of fact,
the light excess would lead to significant and faster camera ageing. Solid
state detectors, in particular Geiger-mode avalanche photo-diodes (G-APDs)
represent a valuable alternative solution to overcome this limitation as
demonstrated in the field by the FACT experiment (The First G- APD Cherenkov
Telescope). They can be regarded as a more promising long term approach, which
can be easily adopted for the new generation of cameras and for the Cherenkov
Telescope Array (CTA). We describe here the Photo-Detector Plane (PDP) of the
camera for the 4 m Davies Cotton CTA Small Size Telescopes, for which large
area G-APD coupled to non-imaging light concentrators are planned. The PDP
includes 1296 photosensors, the biasing and pre-amplification stages, the
control electronics as well as the mechanical support and the water- tight
enclosure. We developed with Hamamatsu a new large area hexagonal shaped G-APD
with an area of 93.6 mm^2. This G-APD is divided into 4 channels which will be
summed after the pre-amplification stage to maintain an acceptable time
characteristic of the signal. The characterization of this device for 50 um and
100 um micro-cell sizes will be discussed and compared to other non-custom
photodetectors.


title: The technique of in-place associative sorting

abstract:
  In the first place, a novel, yet straightforward in-place integer
value-sorting algorithm is presented. It sorts in linear time using constant
amount of additional memory for storing counters and indices beside the input
array. The technique is inspired from the principal idea behind one of the
ordinal theories of "serial order in behavior" and explained by the analogy
with the three main stages in the formation and retrieval of memory in
cognitive neuroscience: (i) practicing, (ii) storage and (iii) retrieval. It is
further improved in terms of time complexity as well as specialized for
distinct integers, though still improper for rank-sorting.
  Afterwards, another novel, yet straightforward technique is introduced which
makes this efficient value-sorting technique proper for rank-sorting. Hence,
given an array of n elements each have an integer key, the technique sorts the
elements according to their integer keys in linear time using only constant
amount of additional memory. The devised technique is very practical and
efficient outperforming bucket sort, distribution counting sort and address
calculation sort family of algorithms making it attractive in almost every case
even when space is not a critical resource.


title: Revised Group Sunspot Number for 1640, 1652, and 1741

abstract:
  Some studies have shown that our knowledge on solar activity in the years
1640, 1652, and 1741 can be improved. In this contribution, we revise the
annual group sunspot numbers for these years from original observations. For
the years 1640, 1652 and 1741, we have obtained the corrected values 15.2, 1.8,
and 27.3, respectively (instead of the original values 15.0, 4.0, and 57.7).


title: DIGIT: Herschel and Spitzer spectro-imaging of SMM3 and SMM4 in Serpens

abstract:
  We report on spectro-imaging observations employing Spitzer IRS and Herschel
PACS, aiming to constrain the physical conditions around SMM3 and SMM4 in
Serpens. The combined power of both instruments provides an almost complete
wavelength coverage between 5 and 200 micron at an angular resolution of 10".
We detect line emission from all major molecular (H2, CO, H2O and OH) and many
atomic ([OI], [CII], [FeII], [SiII] and [SI]) coolants. Line emission tends to
peak at distances of 10 - 20" from the protostellar sources, at positions of
known outflow shocks. The only exception is [CII] which likely traces a PDR
excited from the neighboring source SMM6. Excitation analysis indicates that H2
and CO originate from gas at two distinct rotational temperatures of 300 K and
1000 K, while H2O and OH emission corresponds to rotational temperatures of 100
- 200 K. The morphological and physical association between CO and H2 suggests
a common excitation mechanism which allows direct comparisons between the two
molecules. The CO/H2 abundance ratio varies from 10^-5 in the warm gas up to
10^-4 in the hotter regions. The occurrence of J-shocks is suggested by the
strong atomic/ionic (except for [CII]) emission as well as a number of line
ratio diagnostics. Both C- and J-shocks can account for the observed molecular
emission, however J-shocks are strongly advocated by the atomic emission and
provide simpler and more homogeneous solutions for CO and H2. C-shocks describe
better the emission from H2O and OH. The variations in the CO/H2 abundance
ratio for gas at different temperatures can be interpreted by their reformation
rates in dissociative J-type shocks, or the simultaneous influence of both C
and J shocks.


title:
Composability of partially entanglement breaking channels via
  entanglement assisted local operations and classical communication

abstract:
  We consider composability of quantum channels from a limited amount of
entanglement via local operations and classical communication (LOCC). We show
that any $k$-partially entanglement breaking channel can be composed from an
entangled state with Schmidt number of $k$ via one-way LOCC. From the
entanglement assisted construction we can reach an alternative definition of
partially entanglement breaking channels.


title:
A function on the the set of isomorphism classes in the stable category
  of maximal Cohen-Macaulay modules over a Gorenstein ring: with applications
  to Liason theory

abstract:
  Let $(A,\m)$ be a Gorenstein local ring of dimension $d \geq 1$. Let
$\CMS(A)$ be the stable category of maximal \CM \ $A$-modules and let
$\ICMS(A)$ denote the set of isomorphism classes in $\CMS(A)$. We define a
function $\xi \colon \ICMS(A) \rt \ZZ$ which behaves well with respect to exact
triangles in $\CMS(A)$. We then apply this to (Gorenstein) liason theory. We
prove that if $\dim A \geq 2$ and $A$ is not regular then the even liason
classes of $\m^n; n\geq 1$ is an infinite set. We also prove that if $A$ is an
complete equi-characteristic simple singularity with $A/\m$ uncountable then
for each $m \geq 1$ the set $\mathcal{C}_m = \{I \mid I \ \text{is a codim 2
CM-ideal with} \ e_0(A/I) \leq m \}$ is contained in finitely many even liason
classes $L_1,\ldots,L_r$ (here $r$ may depend on $m$).


title: On the question of diameter bounds in Ricci flow

abstract:
  A question about Ricci flow is when the diameters of the manifold under the
evolving metrics stay finite and bounded away from 0.
  Topping \cite{T:1} addresses the question with an upper bound that depends on
the $L^{(n-1)/2}$ bound of the scalar curvature, volume and a local version of
Perelman's $\nu$ invariant. Here $n$ is the dimension. His result is sharp when
Perelman's F entropy is positive. In this note, we give a direct proof that for
all compact manifolds, the diameter bound depends just on the $L^{(n-1)/2}$
bound of the scalar curvature, volume and the Sobolev constants (or positive
Yamabe constant). This bound seems directly computable in large time for some
Ricci flows. In addition, since the result in its most general form is
independent of Ricci flow, further applications may be possible.
  A generally sharp lower bound for the diameters is also given, which depends
only on the initial metric, time and $L^\infty$ bound of the scalar curvature.
These results imply that, in finite time, the Ricci flow can neither turn the
diameter to infinity nor zero, unless the scalar curvature blows up.


title:
The derivation of continuum limits of neuronal networks with
  gap-junction couplings

abstract:
  We consider an idealized network, formed by N neurons individually described
by the FitzHugh-Nagumo equations and connected by electrical synapses. The
limit for N to infinity of the resulting discrete model is thoroughly
investigated, with the aim of identifying a model for a continuum of neurons
having an equivalent behaviour. Two strategies for passing to the limit are
analysed: i) a more conventional approach, based on a fixed nearest-neighbour
connection topology accompanied by a suitable scaling of the diffusion
coefficients; ii) a new approach, in which the number of connections to any
given neuron varies with N according to a precise law, which simultaneously
guarantees the non-triviality of the limit and the locality of neuronal
interactions. Both approaches yield in the limit a pde-based model, in which
the distribution of action potential obeys a nonlinear
reaction-convection-diffusion equation; convection accounts for the possible
lack of symmetry in the connection topology. Several convergence issues are
discussed, both theoretically and numerically.


title: Current Leads for Superconducting Magnets of ADS Injector I

abstract:
  In ADS Injector I, there are six superconducting magnets in each cryomodule.
Each superconducting magnet contains a solenoid magnet, a horizontal dipole
corrector (HDC) and a vertical dipole corrector (VDC). Six current leads will
be required for powering the electrical circuits, from room temperature to the
2.1K liquid helium bath. Two leads carry 100A current for the solenoid magnet
while the other four carry 12A for the HDC and the VDC. This paper presents the
principle for current lead optimization, which includes the cooling methods,
the choice of material and structure, and the issues for current lead
integration as well.


title: Energy levels and radiative rates for transitions in Ti X

abstract:
  We report calculations of energy levels, radiative rates, oscillator
strengths and line strengths for transitions among the lowest 345 levels of Ti
X. These include 146 levels of the $n \le$ 3 configurations and 86 of 3s$^2
4\ell$, 3s$^2 5\ell$ and 3s3p4$\ell$, plus some of the 3s$^2 6\ell$, 3p$^2
4\ell$ and 3s3p5$\ell$ levels. The general-purpose relativistic atomic
structure package ({\sc grasp}) and flexible atomic code ({\sc fac}) are
adopted for the calculations. Radiative rates, oscillator strengths and line
strengths are provided for all electric dipole (E1), magnetic dipole (M1),
electric quadrupole (E2) and magnetic quadrupole (M2) transitions among the 345
levels, although calculations have been performed for a much larger number of
levels. Comparisons are made with existing results and the accuracy of the data
is assessed. Additionally, lifetimes for all 345 levels are listed. Extensive
comparisons of lifetimes are made for the lowest 40 levels, for which
discrepancies with recent theoretical work are up to 30%. Discrepancies in
lifetimes are even larger, up to a factor of four, for higher excited levels.
Furthermore, the effect of large CI is found to be insignificant for both the
energies and lifetimes for the lowest 40 levels of Ti X which belong to the
3s$^2$3p, 3s3p$^2$, 3s$^2$3d, 3p$^3$ and 3s3p3d configurations. However, the
contribution of CI is more appreciable for the energy levels and radiative
rates among higher excited levels. Our listed energy levels are estimated to be
accurate to better than 1% (within 0.1 Ryd), whereas results for other
parameters are probably accurate to better than 20%.


title:
Time-resolved multicolour photometry of bright B-type variable stars in
  Scorpius

abstract:
  The first two of a total of six nano-satellites that will constitute the
BRITE-Constellation space photometry mission have recently been launched
successfully. In preparation for this project, we carried out time-resolved
colour photometry in a field that is an excellent candidate for BRITE
measurements from space. We acquired 117 h of Stromgren uvy data during 19
nights. Our targets comprised the Beta Cephei stars Kappa and Lambda Sco, the
eclipsing binary Mu 1 Sco, and the variable super/hypergiant Zeta 1 Sco. For
Kappa Sco, a photometric mode identification in combination with results from
the spectroscopic literature suggests a dominant (l, m) = (1, -1) Beta
Cephei-type pulsation mode of the primary star. The longer period of the star
may be a rotational variation or a g-mode pulsation. For Lambda Sco, we recover
the known dominant Beta Cephei pulsation, a longer-period variation, and
observed part of an eclipse. Lack of ultraviolet data precludes mode
identification for this star. We noticed that the spectroscopic orbital
ephemeris of the closer pair in this triple system is inconsistent with eclipse
timings and propose a refined value for the orbital period of the closer pair
of 5.95189 +/- 0.00003 d. We also argue that the components of the Lambda Sco
system are some 30% more massive than previously thought. The binary light
curve solution of Mu 1 Sco requires inclusion of the irradiation effect to
explain the u light curve, and the system could show additional low amplitude
variations on top of the orbital light changes. Zeta 1 Sco shows long-term
variability on a time scale of at least two weeks that we prefer to interpret
in terms of a variable wind or strange mode pulsations.


title: Simultaneous Dual-Species Matter-Wave Accelerometer

abstract:
  We report the realization of a matter-wave interferometer based on Raman
transitions which simultaneously interrogates two different atomic species
($^{87}$Rb and $^{85}$Rb). The simultaneous aspect of our experiment presents
encouraging preliminary results for future dual-species atom interferometry
projects and seems very promising by taking advantage of a differential
acceleration measurement. Indeed the resolution of our differential
accelerometer remains lower than $3.9\times 10^{-8}g$ even with vibration
levels up to $1\times10^{-3}g$ thanks to common-mode vibration noise rejection
. An atom based test of the Weak Equivalence Principle has also been carried
out leading to a differential free fall measurement between both isotopes of
$\Delta g/g = (1.2 \pm 3.2)\times10^{-7}$.


title: An Efficient Multiplication Algorithm Using Nikhilam Method

abstract:
  Multiplication is one of the most important operation in computer arithmetic.
Many integer operations such as squaring, division and computing reciprocal
require same order of time as multiplication whereas some other operations such
as computing GCD and residue operation require at most a factor of $\log n$
time more than multiplication. We propose an integer multiplication algorithm
using Nikhilam method of Vedic mathematics which can be used to multiply two
binary numbers efficiently.